JP7188540B1 - Ultraviolet Laser Print Media, Prints, and Artifacts - Google Patents

Abstract

An object of the present invention is to provide a medium for ultraviolet laser printing, which has excellent visibility of an image printed by ultraviolet laser printing and excellent printability. Furthermore, the present invention provides a printed matter using the ultraviolet laser printing medium, and a processed product using the ultraviolet laser printing medium or the printed matter. [Means for Solving Problem] A base material and a printed layer containing titanium oxide laminated adjacent to the base material, wherein the outermost layer of an ultraviolet laser-printed surface is a layer containing a resin, and the outermost layer is a layer containing a resin. A medium for ultraviolet laser printing, the surface of which has an arithmetic surface roughness (Ra) of 0.3 μm or more and 6.0 μm or less. [Selection figure] None

Description

The present invention relates to ultraviolet laser print media, prints, and artifacts.

2. Description of the Related Art Conventionally, labeling or inkjet printing has been performed in order to display dates such as manufacturing dates and shipping dates, and variable information such as bar codes, on packages such as containers in which items are stored.
In addition, a method of printing by laser light irradiation has also been proposed. For example, Patent Document 1 discloses that clear printing can be performed at high speed by laser light irradiation, and that the printed part has excellent resistance to various lasers. Laminate for laser printing manufactured by coating white ink, black ink and overprint varnish (OP varnish) on the aluminum-deposited surface of aluminum-deposited paper for the purpose of providing a laminate for printing and its printed body. is disclosed.
In addition, Patent Document 2 discloses that, for the purpose of providing a technology that generates relatively little heat and is preferably applicable to laser marking of packaging materials, first titanium oxide particles having an average particle diameter of 150 nm or less are included, and ultraviolet rays An ink composition is disclosed that is used to form a laser marking layer that changes color upon irradiation with a laser.

JP-A-9-123607 JP 2020-75943 A

As means for printing on the surface of packages, labels, adhesive tapes, etc., there is a method in which ink is applied directly to the surface of packages using a thermal printer or an ink jet printer, and these methods are currently widely used. However, consumables such as ink ribbons for thermal printers and ink for inkjet printers are expensive, and printing a large amount of variable information requires high running costs. In addition, failure to replace these consumables may result in printing failure. In addition, offset printing using UV curable ink is also used to directly print fluctuation information on the package, but the surface of the package is dirty and the thickness of the package is uneven. may occur.
In the method described in Patent Document 1, although it is possible to increase the speed, the upper layer that easily absorbs the laser light is removed by irradiating the CO ₂ laser light to expose the lower layer, resulting in a difference in color between the upper layer and the lower layer. Since this is a technology that forms characters that can be seen from the outside, the upper layer is limited to materials that easily absorb laser light, while the lower layer is limited to materials that do not absorb laser light easily and have a color contrast with the upper layer. be done. That is, a carbon black-based material (black) that easily absorbs laser light is the upper layer, and a titanium oxide-based material (white) is the lower layer. Poor visibility.
In the method described in Patent Document 2, although printing is possible by laser irradiation, the reduction in visibility due to reflected light is not considered.

SUMMARY OF THE INVENTION An object of the present invention is to provide a medium for ultraviolet laser printing which is excellent in the visibility of characters, figures and other images printed by ultraviolet laser printing, and which is excellent in printability. Another object of the present invention is to provide a printed matter using the ultraviolet laser printing medium, and a processed product using the ultraviolet laser printing medium or the printed matter.

The present inventors have found that the arithmetic surface roughness (Ra) of the outermost layer of an ultraviolet laser printing medium having a printing layer containing titanium oxide on a base material and a layer containing a resin as the outermost layer is determined to be a specific value. The present inventors have found that the visibility of the printed image is excellent by setting the range, and have completed the present invention. The present invention relates to the following <1> to <9>.
<1> A substrate and a printed layer containing titanium oxide laminated adjacent to the substrate, the outermost layer of the ultraviolet laser-printed surface is a layer containing a resin, and the surface of the outermost layer A medium for ultraviolet laser printing, which has an arithmetic surface roughness (Ra) of 0.3 μm or more and 6.0 μm or less.
<2> The medium for ultraviolet laser printing according to <1>, wherein the content of titanium oxide in the print layer is 0.04 g/m ² or more and 10.0 g/m ² or less.
<3> The medium for ultraviolet laser printing according to <1> or <2>, wherein the base material has an air permeability of 50,000 seconds or less.
<4> The medium for ultraviolet laser printing according to any one of <1> to <3>, wherein the print layer is a laminate layer containing titanium oxide or a coating layer containing titanium oxide.
<5> The medium for ultraviolet laser printing according to any one of <1> to <4>, wherein the printed layer has a thickness of 1.0 μm or more and 60 μm or less.
<6> The medium for ultraviolet laser printing according to any one of <1> to <5>, wherein the print layer is a layer containing the resin.
<7> The medium for ultraviolet laser printing according to any one of <1> to <5>, having a protective layer on the print layer, wherein the protective layer is a layer containing the resin.
<8> A printed material obtained from the ultraviolet laser printing medium according to any one of <1> to <7>, wherein the printed layer contains discolored titanium oxide at least in part. A printed matter having a printed area, wherein the ratio of the Raman intensity derived from titanium oxide in the printed area to the Raman intensity derived from titanium oxide in the non-printed area is 0.70 or less.
<9> A processed product using the ultraviolet laser printing medium according to any one of <1> to <7> or the printed matter according to <8>.

ADVANTAGE OF THE INVENTION According to this invention, the medium for ultraviolet laser printing which is excellent in the visibility of the image printed by ultraviolet laser printing, such as a character, a figure, etc., and is also excellent in printability is provided. Further, according to the present invention, there are provided printed matter using the ultraviolet laser printing medium, and processed products using the ultraviolet laser printing medium or printed matter.

BRIEF DESCRIPTION OF THE DRAWINGS It is a cross-sectional schematic diagram which shows one implementation of the medium for ultraviolet laser printing of this embodiment. It is a cross-sectional schematic diagram which shows other one Embodiment of the medium for ultraviolet laser printing of this embodiment.

[Media for UV laser printing]
The ultraviolet laser printing medium of the present embodiment (hereinafter also simply referred to as "printing medium") has a substrate and a titanium oxide-containing printing layer laminated adjacent to the substrate, The outermost layer of the laser-printed surface is a layer containing a resin, and the surface arithmetic surface roughness (Ra) of the outermost layer is 0.3 μm or more and 6.0 μm or less.
According to the present embodiment, there is provided an ultraviolet laser printing medium which is excellent in the visibility of characters, figures and other images printed by ultraviolet laser printing, and which is excellent in printability. The term "excellent in printability" means that the unevenness of ink application is suppressed and the finish is good.
Although the detailed reason why the above effect is obtained is unknown, part of it is considered as follows. In the present invention, a printed layer having titanium oxide is laminated on a substrate and adjacent to the substrate. By having a printed layer containing titanium oxide on the base material, the titanium oxide in the printed layer changes color upon irradiation with an ultraviolet laser, making it possible to print. The discoloration of the titanium oxide is caused by the ion valence of the titanium oxide contained in the printed layer changing from tetravalent to trivalent, causing oxygen defects, thereby changing from white to black, thereby becoming visible. It is thought that It is considered that the ionic valence of titanium oxide changes when it is irradiated with light energy corresponding to the bandgap of titanium oxide. Although the bandgap of titanium oxide differs depending on the crystal system, it is generally about 3.0 to 3.2 eV, and the corresponding light wavelength is 420 nm or less. Therefore, even if a laser beam with a wavelength exceeding 420 nm (eg, 532 nm, 1064 nm, 10600 nm) is used, it is difficult to perform printing due to the ion valence change of titanium oxide as in the present invention.

A printed matter can be obtained by discoloring titanium oxide by irradiation with an ultraviolet laser. On the other hand, the discolored titanium oxide is light gray, and when the outermost surface of the medium for ultraviolet laser printing is a layer containing a resin, if the layer containing the resin is smooth, it has a gloss, so the reflected light It has been found that there is a problem that the visibility is inferior due to the overlap of In the present invention, by setting the arithmetic surface roughness (Ra) of the surface of the resin-containing layer, which is the outermost layer, to 0.3 μm or more, it is believed that the reflection of light is suppressed and the visibility of the image is improved. be done.
Further, when the printing medium is used for packaging, etc., gravure printing or the like may be applied. By setting the arithmetic mean roughness (Ra) to 6.0 μm or less, the printing surface is not excessively roughened, and it is considered that the printing aptitude for printing such as gravure printing is excellent.
The present invention will be described in more detail below.

The ultraviolet laser printing medium of this embodiment will be described with reference to the drawings.
FIG. 1 is a schematic cross-sectional view showing one embodiment of the medium for ultraviolet laser printing of the present embodiment. The ultraviolet laser printing medium 100 shown in FIG. 1 has a substrate 10 and a print layer 20 containing titanium oxide laminated adjacent to the substrate 10 . In the medium for ultraviolet laser printing shown in FIG. 1, the printed layer 20 is a resin-containing layer that constitutes the outermost layer of the ultraviolet laser printing surface.
FIG. 2 is a schematic cross-sectional view showing another embodiment of the ultraviolet laser printing medium of this embodiment. The ultraviolet laser printing medium 100 shown in FIG. 2 has a substrate 10 , a printing layer 20 containing titanium oxide laminated adjacent to the substrate 10 , and a protective layer 30 . In the ultraviolet laser printing medium shown in FIG. 2 , a protective layer 30 is laminated on the printing layer 20 . In the ultraviolet laser printing medium shown in FIG. 2, the protective layer 30 is a resin-containing layer constituting the outermost layer of the ultraviolet laser printing surface. Preferably, the protective layer 30 does not substantially contain titanium oxide.
The medium for ultraviolet laser printing has a printed layer on the substrate, and the printed layer may be formed on at least one side of the substrate, and may be formed on both sides. It is preferable to have Moreover, although the paper base material may have the printing layer on the entire surface, it may have the printing layer only on a partial area (portion) where printing is desired.

<Base material>
In the present embodiment, the substrate is not particularly limited as long as it is a substrate on which a printed layer can be provided. Just do it.
Among these, from the viewpoint of easy formation of the coating layer, oxygen generated during printing with an ultraviolet laser or water vapor generated by volatilization of moisture in the printing medium by the ultraviolet laser is easily released from the substrate side. From the viewpoint, it is more preferably at least one selected from paper, nonwoven fabric and cloth, more preferably at least one selected from paper and nonwoven fabric, and still more preferably paper. When the substrate is paper, the substrate is also called a paper substrate.
In addition, for example, the paper substrate may be a coated paper in which a coating layer is provided on the paper, and the coating layer may be provided on the printing layer side of the paper substrate, or on the opposite side. , and is not particularly limited.

(Paper substrate)
Examples of the raw pulp that constitutes the paper substrate include wood pulp, non-wood pulp, and deinked pulp. The wood pulp is not particularly limited. SP), dissolving pulp (DP), soda pulp (AP), chemical pulp such as oxygen bleached kraft pulp (OKP), semi-chemical pulp (SCP), semi-chemical pulp such as chemigroundwood pulp (CGP), groundwood pulp ( GP), thermomechanical pulp (TMP), chemithermomechanical pulp (CTMP) and other mechanical pulps. Examples of non-wood pulp include, but are not limited to, cotton pulp such as cotton linter and cotton lint, and non-wood pulp such as hemp, straw, bamboo and bagasse. The deinked pulp is not particularly limited, but examples thereof include deinked pulp made from waste paper. The raw material pulp may be used singly or in combination of two or more. Organic synthetic fibers such as polyamide fibers and polyester fibers, regenerated fibers such as polynosic fibers, and inorganic fibers such as glass fibers, ceramic fibers, and carbon fibers may be mixed with the raw material pulp.
The raw material pulp is preferably wood pulp or deinked pulp from the viewpoint of availability. Among wood pulps, raw material pulp is preferably chemical pulp, more preferably kraft pulp, and still more preferably hardwood kraft pulp such as eucalyptus and acacia, and pine and cedar pulp, from the viewpoint of texture uniformity. One or more selected from softwood kraft pulp such as, more preferably one or more selected from hardwood bleached kraft pulp (LBKP) and softwood bleached kraft pulp (NBKP), particularly preferably LBKP .

A paper base material is obtained by paper-making a pulp slurry to which an internal additive is added as necessary.
In addition to the pulp described above, the paper base material includes fillers, sizing agents, dry strength agents, wet strength agents (e.g., polyamide polyamine epichlorohydrin), retention aids (e.g., aluminum sulfate), Known internal additives for papermaking such as drainage improvers, pH adjusters, softeners, antistatic agents, antifoaming agents, dyes and pigments can be added as necessary.
Examples of fillers include kaolin, talc, titanium oxide, heavy calcium carbonate, light calcium carbonate, calcium sulfite, gypsum, calcined kaolin, white carbon, amorphous silica, delaminated kaolin, diatomaceous earth, magnesium carbonate, hydroxide Aluminum, calcium hydroxide, magnesium hydroxide, zinc hydroxide and the like can be exemplified.
Examples of sizing agents include rosin-based, alkylketene dimer-based, alkenyl succinic anhydride-based, styrene-acrylic, higher fatty acid-based, and petroleum resin-based sizing agents.

In the papermaking of the paper substrate, a known wet paper machine such as a fourdrinier paper machine, a gap former paper machine, a cylinder paper machine, a short mesh paper machine, etc. may be appropriately selected and used. can be done. Next, the paper layer formed by the paper machine is conveyed by felt and dried by a dryer. A multi-stage cylinder dryer may be used as a pre-dryer before drying.

Further, the paper base material obtained as described above may be subjected to a surface treatment using a calendar to make the thickness and profile uniform, thereby improving the printability. For calendering, a known calendering machine can be appropriately selected and used.

The paper substrate may be appropriately selected and used from conventionally known paper substrates such as liner base paper, kraft paper, woodfree paper, and coated paper.
Moreover, the paper base material may be a single layer or a multi-layer, or may have a multi-layer structure with different pulp compositions.

The Canadian standard freeness (CSF) of the wood pulp used for the paper substrate is preferably 150 mL or more, more preferably 300 mL or more, from the viewpoint of obtaining the strength and smoothness required for the paper substrate. More preferably 400 mL or more, and preferably 800 mL or less, more preferably 750 mL or less, and even more preferably 700 mL or less.
Here, CSF is the Canadian standard freeness according to JIS P 8121-2:2012.

The basis weight of the paper substrate is preferably 30 g/m ² or more, more preferably 40 g/m ² or more, still more preferably 50 g/m 2 or more, from the viewpoint of strength as a printing medium and ease of processing as a package. ² or more, more preferably 60 g/m ² or more, and preferably 700 g/m ² or less, more preferably 500 g/m ² or less, still more preferably 350 g/m ² or less.
The basis weight is measured by the method specified in JIS P 8124:2011.

The thickness of the paper substrate is not particularly limited, but is preferably 30 µm or more, more preferably 50 µm or more, still more preferably 70 µm or more, and still more preferably from the viewpoint of strength as a printing medium and ease of processing as a package. is 80 μm or more, and preferably 900 μm or less, more preferably 700 μm or less, and even more preferably 500 μm or less.
The thickness of the paper substrate can be measured by the method described in JIS P 8118:2014.

The density of the paper substrate is not particularly limited, but it is preferably 0.50 g/cm ³ or more, more preferably 0.60 g/cm ³ or more, from the viewpoint of strength as a printing medium and ease of processing as a package. , more preferably 0.65 g/cm ³ or more, and preferably 1.20 g/cm ³ or less, more preferably 1.00 g/cm ³ or less, still more preferably 0.90 g/cm ³ or less.
The density of the paper substrate is calculated from the basis weight and paper thickness of the paper substrate described above.

(cloth, non-woven fabric)
When the base material is cloth or non-woven fabric, raw materials that constitute the cloth and non-woven fabric include natural fibers such as cotton, hemp, cellulose fiber, and wool; synthetic fibers such as polycarbonate, polyetherimide, polyester, polyurethane, and polyamide ( nylon), etc.; rayon, acetate, etc., which are regenerated fibers, are exemplified.

From the viewpoint of improving the smoothness after printing, the air permeability of the substrate is preferably 50,000 seconds or less, more preferably 30,000 seconds or less, and still more preferably 15,000 seconds or less. Not limited.
When the titanium oxide is irradiated with the ultraviolet laser, oxygen and moisture contained in the titanium oxide are volatilized to generate water vapor as the titanium oxide is reduced. By setting the air permeability of the base material to 50,000 seconds or less, the generated oxygen and water vapor permeate the base material side, thereby suppressing the occurrence of unevenness on the surface of the printed material, which is preferable.
The air permeability of the substrate is measured by the method described in Examples.

<Print layer>
Ultraviolet laser print media have a print layer containing titanium oxide laminated adjacent to a substrate. The printed layer may be provided by lamination or coating, and is not particularly limited. The printed layer is preferably a laminate layer containing titanium oxide or a coating layer containing titanium oxide.

The content of titanium oxide in the printing layer is preferable from the viewpoint of obtaining sufficient printing density and from the viewpoint of suppressing light reflection on the surface of the printing medium by increasing the content of titanium oxide having a high refractive index. is 0.04 g/m ² or more, more preferably 0.1 g/m ² or more, still more preferably 0.2 g/m ² or more, still more preferably 0.3 g/m ² or more, particularly preferably 0.5 g/m 2 or more m ² or more, and the printing density peaks out, from the viewpoint of suppressing the cost increase due to containing more titanium oxide than necessary, from the viewpoint of the ease of forming the printed layer, and by increasing the content of titanium oxide , from the viewpoint of suppressing a decrease in printing density due to smoke generation during ultraviolet laser irradiation, it is preferably 10.0 g/m ² or less, more preferably 5.0 g/m ² or less, and still more preferably 3.0 g/m ² . It is below.

The thickness of the printing layer is preferably 1.0 μm or more, more preferably 1.5 μm or more, and still more preferably 3.0 μm or more, from the viewpoint of increasing the printing density. From the viewpoint of suppressing , and the viewpoint of improving smoothness after printing, the thickness is preferably 60 µm or less, more preferably 45 µm or less, and still more preferably 30 µm or less.
When the thickness of the printed layer is 1.0 μm or more, the absorption of the laser light occurs in the entire thickness direction during irradiation with the ultraviolet laser, so that the printing density is increased and an image with excellent visibility can be obtained, which is preferable. Also, if the print layer is too thick, the oxygen generated by the reduction of titanium oxide due to the irradiation of the ultraviolet laser and the water vapor generated by volatilization of water in the print medium will be difficult to escape from the print layer. , unevenness tends to occur in the printed matter. It is preferable that the thickness of the printed layer is 60 μm or less because the occurrence of the unevenness is suppressed.
The thickness of the print layer is measured from a cross-sectional electron microscope (SEM) image of the print medium.

The print layer preferably contains a thermoplastic resin in addition to titanium oxide.
(Titanium oxide)
When the print layer is provided by coating, titanium oxide is preferably contained in a coating liquid and applied, and the coating liquid is more preferably an aqueous coating liquid.
On the other hand, when titanium oxide is provided by lamination, it is preferably contained in the laminated film.

Titanium oxide contained in the printed layer is represented by the composition formula TiO ₂ and is also called titanium dioxide or titania.
Any titanium oxide may have a crystalline structure or may be amorphous, and may be at least one selected from rutile-type titanium oxide, anatase-type titanium oxide, brookite-type titanium oxide, and amorphous titanium oxide. From the viewpoint of availability and stability, it is more preferably at least one selected from rutile-type titanium oxide and anatase-type titanium oxide, and rutile-type titanium oxide is even more preferable.
The crystal form of titanium oxide can be determined by a known method, specifically by Raman spectrum, XRD pattern analysis, and the like. For example, when identifying from the Raman spectrum, in general, the rutile type has peaks at 447±10 cm ⁻¹ and 609±10 cm ⁻¹ , and the anatase type has peaks at 395±10 cm ⁻¹ and 516±10 cm. A peak is confirmed at ⁻¹ , 637±10 cm ⁻¹ .
Titanium oxide may be used individually by 1 type, and may use 2 or more types together.

The shape of titanium oxide is not particularly limited, and may be any shape such as irregular, spherical, rod-like, and needle-like.
When the titanium oxide is amorphous or spherical, the particle size of the titanium oxide is not particularly limited, but from the viewpoint of obtaining a printing medium with excellent surface smoothness, it is preferably 0.01 μm or more, more preferably 0.10 μm or more, and further preferably 0.10 μm or more. It is preferably 0.15 μm or more, and is preferably 20.0 μm or less, more preferably 10.0 μm or less, even more preferably 5.0 μm or less, even more preferably 3.0 μm or less, and particularly preferably 1.0 μm or less. is.
The particle size of titanium oxide in the printed layer was obtained from a scanning electron microscope (SEM, S5200, manufactured by Hitachi High-Tech Co., Ltd., etc.) obtained by burning the printing medium or printed material in a muffle furnace at 525°C. It is calculated from the SEM image obtained.
The ash sample to be subjected to the scanning electron microscope was dispersed in ethanol for 5 minutes with an ultrasonic homogenizer (manufactured by Yamato Scientific Co., Ltd., LUH150, etc.) with an output of 50 W to obtain a 0.01% by mass slurry. After casting 0.1 mL onto a dish and drying at 60° C., an aluminum dish was cut into an appropriate size for SEM. Adjacent particles that can be clearly distinguished from each other are visually selected, and the major axis of one particle is defined as the particle diameter. At this time, if the primary particles and the secondary particles in the agglomerated state are mixed but can be clearly distinguished, each of them is counted as one particle, and the average diameter of 100 randomly selected particles is taken as the particle diameter. do. The magnification during SEM image observation may be appropriately selected according to the particle size of the titanium oxide, but is preferably about 20000 times. When particles other than titanium oxide are contained, particles containing titanium element are measured using an energy dispersive X-ray analyzer (EMAX, manufactured by HORIBA, Ltd.) attached to the SEM.
When the substrate contains titanium oxide, an ash sample is prepared by transferring the printed layer to a transparent adhesive tape (309SN manufactured by 3M Co., Ltd., etc.) that does not contain titanium oxide or inorganic pigments. Specifically, the pressure-sensitive adhesive tape is applied to the upper layer of the printed layer using a tape pressure bonding roller (manufactured by Yasuda Seiki Seisakusho Co., Ltd., No. 349, etc.) having a roller mass of 2 kg. After that, the tape is immersed in a copper ethylenediamine solution for cellulose viscosity measurement (manufactured by Merck & Co., etc.) for 24 hours, and then the adhesive tape including the printed layer is thoroughly washed with deionized water. The pressure-sensitive adhesive tape containing the obtained printed layer is wiped off and dried in a drier at 60° C. for 1 hour. Then, it is burned in a muffle furnace at 525° C. to prepare ash used for particle size measurement, and the particle size is measured by the same method as above.
The average particle size of titanium oxide particles used as a raw material can be obtained as a median size measured by a laser diffraction/scattering particle size distribution analyzer (manufactured by Horiba, Ltd., LA-300, etc.). Measurement conditions are preferably as follows. The average particle size obtained from a laser diffraction/scattering particle size distribution meter may deviate from the particle size calculated from a scanning electron micrograph by about ±50%.
Dispersion medium: deionized water,
measured particle refractive index: 2.75-0.01i,
Solvent refractive index: 1.333,
Built-in ultrasonic irradiation (30W): 3 minutes,
Circulation speed: 3

When the titanium oxide is acicular, the major diameter of the titanium oxide is not particularly limited, but from the viewpoint of obtaining a printing medium with excellent surface smoothness, it is preferably 0.1 μm or more, more preferably 0.5 μm or more, It is more preferably 1.5 μm or more, and preferably 50.0 μm or less, more preferably 30.0 μm or less, still more preferably 15.0 μm or less. In addition, the minor axis is preferably 0.01 μm or more, more preferably 0.03 μm or more, still more preferably 0.05 μm or more, and preferably 3.0 μm or less, more preferably 1.5 μm or less, and still more preferably is 1.0 μm or less. Further, when the titanium oxide is acicular, the aspect ratio (major axis/minor axis) is preferably 5 or more, more preferably 10 or more, still more preferably 15 or more, and preferably 300 or less, more preferably It is 100 or less, more preferably 30 or less.
The major axis and minor axis of titanium oxide contained in the printed layer were determined by treating the ash obtained by burning the printing medium or printed matter in a muffle furnace in the same manner as described above, and using a scanning electron microscope (SEM, manufactured by Hitachi High-Tech Co., Ltd.). , S5200, etc.). A powder to be tested for scanning electron microscopy is obtained in the same manner as described above.
In addition, the major axis and minor axis of titanium oxide used as a raw material can also be measured from an SEM image obtained from a scanning electron microscope.
When the substrate contains titanium oxide, an ash sample is prepared by transferring the printed layer to a transparent adhesive tape (309SN, manufactured by 3M Co., Ltd., etc.) that does not contain titanium oxide or inorganic pigments. Specifically, the pressure-sensitive adhesive tape is applied to the upper layer of the printed layer using a tape pressure bonding roller (manufactured by Yasuda Seiki Seisakusho Co., Ltd., No. 349, etc.) having a roller mass of 2 kg. After that, the tape is immersed in a copper ethylenediamine solution for cellulose viscosity measurement (manufactured by Merck & Co., etc.) for 24 hours, and then the adhesive tape including the printed layer is thoroughly washed with deionized water. The pressure-sensitive adhesive tape containing the obtained printed layer is wiped off and dried in a drier at 60° C. for 1 hour. After that, it is burned in a muffle furnace at 525° C. to prepare ash used for particle size measurement, and the major axis and minor axis are measured by the same method as above.
The particle size, major axis and minor axis of titanium oxide are measured by the method described in Examples. Note that the values of the particle size, major axis, and minor axis of the titanium oxide used as the raw material may be used.

(Thermoplastic resin)
A thermoplastic resin used in the printing layer functions as a binder.
The thermoplastic resin of the printed layer is not particularly limited, but when the printed layer is provided by coating, that is, when the printed layer is a coating layer, it is preferable to apply it as an aqueous coating liquid. A dilutable thermoplastic resin is preferred.
Examples of water-dilutable resins include water-soluble, emulsion-type, and dispersion-type resins.
The water-dilutable thermoplastic resin may be either a natural resin or a synthetic resin. resins, styrene-butadiene-based resins, vinyl chloride-based resins, and polyolefin-based resins.
More specifically, acrylic resins include acrylic resins obtained by copolymerizing (meth)acrylic acid and its alkyl ester or styrene as monomer components, ethylene-(meth)acrylic acid copolymers, styrene- Acrylic acid-maleic acid resins are exemplified. Examples of maleic acid-based resins include styrene-maleic acid resins.
Among these, starch derivatives, casein, shellac, polyvinyl alcohol and its derivatives, acrylic resins, styrene-butadiene resins, and maleic acid resins are used from the viewpoint of the stability of the coating liquid and the solvent resistance of the coating layer. At least one selected from is preferable, and at least one selected from starch derivatives, polyvinyl alcohol, polyvinyl alcohol derivatives, acrylic resins, styrene-butadiene-based resins, and maleic acid-based resins is more preferable, starch derivatives, polyvinyl alcohol, At least one selected from polyvinyl alcohol derivatives, acrylic resins, and styrene-butadiene-based resins is more preferred, and at least one selected from polyvinyl alcohols, polyvinyl alcohol derivatives, acrylic resins, and styrene-butadiene-based resins is more preferred. preferable.
These resins may be used individually by 1 type, and may use 2 or more types together.
When using an organic solvent-based coating liquid, it is preferable to use known thermoplastic resins such as cellulose resins, polyurethane resins, acrylic resins, and vinyl chloride copolymer resins.

The content of the thermoplastic resin is not particularly limited, and may be appropriately selected according to the type of thermoplastic resin, the content of titanium oxide in the coating liquid, the content of inorganic pigments described later, etc. For example, the coating liquid of the solid content, preferably 5% by mass or more, more preferably 10% by mass or more, still more preferably 15% by mass or more, and preferably 99% by mass or less, more preferably 98% by mass or less.

The coating liquid is preferably an aqueous coating liquid, and the aqueous medium used includes water or a mixture of water and a water-miscible solvent.
Water-miscible solvents include lower alcohols, polyhydric alcohols, and their alkyl ethers or esters. Specifically, lower alcohols such as methyl alcohol, ethyl alcohol, normal propyl alcohol and isopropyl alcohol, polyhydric alcohols such as ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol and glycerin, ethylene glycol monomethyl ether, ethylene Glycol monoethyl ether, ethylene glycol monoacetate, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monoacetate, diethylene glycol monomethyl ether, dipropylene glycol monomethyl ether and the like.
In the case of an organic solvent-based coating liquid, aromatic organic solvents such as toluene and xylene, ethyl acetate, n-propyl acetate, isobutyl acetate, ester-based organic solvents, and ketone-based organic solvents such as methyl ethyl ketone and methyl isobutyl ketone. , methanol, ethanol, isopropanol, n-butanol and other alcohol-based organic solvents, and methylcyclohexane and other hydrocarbon-based solvents.

The solid content concentration of the coating liquid is not particularly limited, but from the viewpoint of obtaining a desired thickness of the coating layer, the viewpoint of making the coating liquid a viscosity that facilitates coating, and the viewpoint of easiness of drying, it is preferably 10% by mass. Above, more preferably 20% by mass or more, still more preferably 30% by mass or more, and preferably 80% by mass or less, more preferably 70% by mass or less, still more preferably 65% by mass or less.

When the printed layer is provided by lamination, that is, when the printed layer is a laminated layer, it is preferable to laminate a film containing titanium oxide on the substrate.
The thermoplastic resin that constitutes the laminate layer is not particularly limited as long as it can be processed into a film by encapsulating titanium oxide, and may be appropriately selected from known thermoplastic resins. Specifically, polyester resins such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyvinyl chloride, polyvinylidene chloride, polybutene, polybutadiene, ethylene-vinyl acetate copolymer, polyethylene, polypropylene, ethylene-propylene copolymer Polyolefin resins such as coalescence and polymethylpentene; polycarbonate; polyurethane; polyamide; polyacrylonitrile;
Among them, the resin constituting the laminate layer can be used for general purposes, has a high ultraviolet transmittance, and is capable of discoloring titanium oxide to the inside of the laminate layer. It preferably contains polyolefins such as ethylene-propylene copolymers, polyesters such as polyethylene terephthalate, polybutylene terephthalate, polylactic acid, and polybutylene succinate, and includes polyethylene, polypropylene, ethylene-propylene copolymers, polyethylene terephthalate, and polylactic acid. , and polybutylene succinate, more preferably at least one selected from the group consisting of polyethylene, polypropylene, ethylene-propylene copolymer, polyethylene terephthalate, polylactic acid, and polybutylene succinate It is more preferable that it is at least one selected from The resin constituting the laminate layer is more preferably polyolefin, and more preferably at least one selected from the group consisting of polyethylene and polypropylene. Polyethylene (PE) is roughly classified into linear low density polyethylene (LLDPE), low density polyethylene (LDPE), medium density polyethylene (MDPE), and high density polyethylene (HDPE). Among these, low-density polyethylene (LDPE) is preferred because of its excellent extrusion lamination properties.
As the resin constituting the laminate layer, it is preferable to use polyester, which is a biodegradable resin, in terms of reducing the environmental load. Examples thereof include polylactic acid and polybutylene succinate.
These resins may be used individually by 1 type, and may use 2 or more types together.

The content of the thermoplastic resin in the laminate layer is preferably 20.0% by mass or more, more preferably 30.0% by mass or more, from the viewpoint of improving printability and suppressing smoke generation during ultraviolet laser irradiation. It is more preferably 50.0% by mass or more, and preferably 99.9% by mass or less, more preferably 99.0% by mass or less, still more preferably 98.0% by mass or less, and even more preferably 97.0% by mass. % by mass or less.

The printed layer may contain other components in addition to the titanium oxide and thermoplastic resin described above.
Examples of other components include inorganic pigments other than titanium oxide. Inorganic pigments include kaolin, talc, calcium carbonate, calcium sulfite, gypsum, calcined kaolin, white carbon, amorphous silica, delaminated kaolin, diatomaceous earth, magnesium carbonate, aluminum hydroxide, calcium hydroxide, magnesium hydroxide, Zinc oxide, zinc hydroxide and the like are exemplified, and among these, kaolin and calcium carbonate are preferred from the viewpoint of improving printability and availability.
Calcium carbonate may be heavy calcium carbonate or light calcium carbonate, and is not particularly limited, but heavy calcium carbonate is preferred.
By containing an inorganic pigment other than titanium oxide, printability is improved, scattering of titanium oxide is suppressed during ultraviolet laser irradiation, a printed matter with high print density is obtained, and smoking is also suppressed, which is preferable. In particular, when the printed layer is a coating layer, it is preferable to contain an inorganic pigment also from the viewpoint of improving the whiteness of the printed layer.

The shape of the inorganic pigment is not particularly limited, and may be any shape such as amorphous, spherical, rod-like, and needle-like.
When the printed layer contains an inorganic pigment, the content of the inorganic pigment in the printed layer is preferably 5% by mass or more, more preferably 10% by mass, from the viewpoint of improving printability and obtaining a printed matter with high print density. % by mass or more, more preferably 30% by mass or more, and preferably 90% by mass or less, more preferably 85% by mass or less, and even more preferably 80% by mass or less.
The inorganic pigments other than titanium oxide may be used singly or in combination of two or more. When two or more kinds are used in combination, the total content of the inorganic pigments excluding titanium oxide is preferably the above content.

In the print medium of the present embodiment, in addition to the components described above, other components may be added to the print layer within a range that does not impair the effects of the present invention, such as antistatic agents and antiblocking agents. , antioxidants, antifoaming agents, film forming agents, pigment dispersants, viscosity modifiers and the like.

[Coating liquid]
When the print layer is provided by coating, the coating liquid is obtained by mixing the above various materials with an aqueous medium. Prior to mixing with the aqueous medium, titanium oxide, thermoplastic resin, water, and if necessary, water-miscible solvent, pigment dispersant, pigment dispersant resin, etc. are mixed and kneaded, and water is further added. , a water-miscible solvent, if desired, and the remainder of the given ingredients may be added and mixed.
The coating liquid can be obtained by mixing and dispersing the above components with a high-speed stirrer such as a homomixer or a lab mixer, or a disperser such as a three-roll mill or a bead mill.

The method of applying the coating liquid is not particularly limited, and may be applied to the substrate by flexographic printing, inkjet printing, gravure printing, screen printing, pad printing, spray coating, or the like.

[Laminate layer (film)]
The film constituting the laminate layer is prepared by preparing a raw material composition by melt-kneading at least titanium oxide and a thermoplastic resin, and if necessary, materials such as inorganic pigments. Obtained by stretching.
In preparing the raw material composition, a masterbatch containing titanium oxide or inorganic pigment at a high concentration may be prepared and then mixed with the resin.
Moreover, the materials that have been uniformly mixed in advance may be charged into the molding machine, or the materials may be mixed in a hopper or a kneader integrated with the molding machine.
A method for forming a film may be appropriately selected from conventionally known methods, such as a melt extrusion method, a melt casting method, a calendering method, and the like.

The substrate and film may be attached via an adhesive layer, or preferably laminated.
The adhesive layer is not particularly limited, and may be appropriately selected from known adhesive layers and used. Specifically, the adhesive layer disclosed in JP-A-2012-57112 is exemplified.
Specific examples of lamination processing include laminating a paper substrate and a laminate layer by a heat lamination method, a dry lamination method, a wet lamination method, an extrusion lamination method, or the like.
Among these methods, the extrusion lamination method is preferable from the viewpoint of the manufacturing process because it does not require a step of attaching the laminate layer and the paper substrate.

<Protective layer>
From the viewpoint of improving waterproofness and antifouling properties, the printing medium of the present embodiment may have a protective layer as a layer containing a resin on the substrate and the printing layer to improve printing density. From this point of view, when the printed layer is a coating layer, it is preferable to have a protective layer. In this case, the configuration shown in FIG. 2 is used.
The thermoplastic resin used for the protective layer is not particularly limited as long as it can be laminated on the printing layer, and may be appropriately selected from known thermoplastic resins.
Specifically, polyester resins such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polylactic acid, and polybutylene succinate, polyvinyl chloride, polyvinylidene chloride, polybutene, polybutadiene, ethylene-vinyl acetate copolymer, Polyolefin resins such as polyethylene, polypropylene, ethylene-propylene copolymer, polymethylpentene; polycarbonate; polyurethane; polyamide; polyacrylonitrile; Polyolefins such as copolymers, polyesters such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polylactic acid and polybutylene succinate are preferred, and polyethylene, polypropylene, polyethylene terephthalate, polylactic acid and polybutylene succinate are more preferred. , polyethylene, and polypropylene are more preferred, and polyethylene is even more preferred.
In addition to the above materials, biomass resins and biodegradable resins may be used as resins.
These resins may be used individually by 1 type, and may use 2 or more types together.
Among the above thermoplastic resins, polyethylene is preferred because of its excellent extrusion lamination properties and barrier properties.
Polyethylene (PE) is roughly classified into linear low density polyethylene (LLDPE), low density polyethylene (LDPE), medium density polyethylene (MDPE), and high density polyethylene (HDPE). Among these, low-density polyethylene (LDPE) is preferred because of its excellent extrusion lamination properties.
The laminate layer may be produced by appropriately selecting from conventionally known production methods, for example, from melt extrusion, melt casting, calendering, and the like.

The total light transmittance of the protective layer is preferably 40% or more, more preferably 60% or more, still more preferably 80% or more, and even more preferably 90% or more, and the upper limit is not particularly limited. 100% or less.
Total light transmittance is measured according to JIS K 7361-1:1997.

Although the thickness of the protective layer is not particularly limited, it is preferably 5 μm or more, more preferably 10 μm or more, and still more preferably 15 μm or more from the viewpoint of obtaining clear printing and handling properties of the printing medium and printed matter, and , preferably 300 μm or less, more preferably 100 μm or less, still more preferably 50 μm or less.

[Layer containing resin]
In the printing medium of the present embodiment, the outermost surface of the ultraviolet laser-printed surface is a layer containing a resin, and the surface arithmetic mean roughness (Ra) of the outermost layer of the ultraviolet laser-printed surface is 0.3 μm or more and 6.0 μm. It is below.
The layer containing the resin may be a printed layer or a protective layer as described above, and is not particularly limited.
When the arithmetic mean roughness (Ra) is 0.3 μm or more, the reflection of light on the laser-printed surface is suppressed, and the visibility of the image is improved, which is preferable. Further, when the arithmetic mean roughness (Ra) is 6.0 μm or less, the printability is excellent, which is preferable.
The arithmetic mean roughness (Ra) of the surface of the outermost layer of the ultraviolet laser-printed surface is preferably 0.4 μm or more, more preferably 0.5 μm or more, still more preferably 0.6 μm or more, from the above-mentioned viewpoints, and , preferably 5.5 μm or less, more preferably 4.5 μm or less, still more preferably 3.5 μm or less, even more preferably 2.5 μm or less, and particularly preferably 1.5 μm or less.
The arithmetic mean roughness (Ra) can be adjusted by selecting the smoothness of the roller surface when the surface of the resin-containing layer is calendered with a cooling roll or the like.
The arithmetic mean roughness (Ra) is measured by the method described in Examples.

[Printed matter and method for producing printed matter]
The method for producing a printed matter according to the present embodiment includes the step of irradiating the above-described ultraviolet laser printing medium with an ultraviolet laser to change the color of the irradiated area for printing.
Further, the printed matter of the present embodiment is a printed matter obtained from the ultraviolet laser printing medium described above, and has a printed area having discolored titanium oxide in at least a part thereof. The ratio of the Raman intensity derived from titanium oxide in the printed region to the Raman intensity derived from titanium oxide in the non-printed region is preferably 0.70 or less. Further, the printed region having discolored titanium oxide is a region containing titanium oxide discolored by irradiation with an ultraviolet laser, and is an ultraviolet laser irradiated region, that is, a printed region.
Examples of the printing medium used in the printed matter and the printed matter manufacturing method of the present embodiment include the above-mentioned printing media, and the preferred range is also the same. Further, in the printed matter and the method for producing the printed matter of the present embodiment, at least the ultraviolet laser irradiation region may have a printed layer on the base material, and the printed layer may not be provided in the region where printing is not performed. good.

It is preferable to irradiate the ultraviolet laser so that the ratio of the Raman intensity derived from titanium oxide in the printed region to the Raman intensity derived from titanium oxide in the non-printed region is 0.70 or less. That is, in the printed matter of the present embodiment, the ratio of the Raman intensity derived from titanium oxide in the printed region to the Raman intensity derived from titanium oxide in the non-printed region is preferably 0.70 or less.
In the printed matter, the printed region means a region (portion) containing discolored titanium oxide in the printable region, and is a region (portion) printed with an ultraviolet laser. A non-printing area means a non-printing area (portion) in the printable area. In addition, the printable area is the entire area containing titanium oxide, including the area that can be printed with an ultraviolet laser and the printable area that has been printed with an ultraviolet laser, if any, in an ultraviolet laser printing medium or printed matter. and the non-printable area means an area other than the printable area in the ultraviolet laser printing medium or printed matter.
The ratio of the Raman intensity derived from titanium oxide in the printed region to the Raman intensity derived from titanium oxide in the non-printed region (Raman intensity in the printed region/Raman intensity in the non-printed region) is 0.70 or less. Printing is preferred. By setting the ratio of Raman intensities within the above range, a printed matter with excellent visibility can be obtained.
When rutile-type titanium oxide is used as titanium oxide, the Raman intensity ratio (Raman intensity in printed area/Raman intensity in non-printed area) is 447±10 cm ⁻ as Raman intensity derived from titanium oxide. Contrast the maximum Raman intensity in the wavenumber range of ¹ . When anatase-type titanium oxide is used as titanium oxide, the maximum Raman intensity in the wavenumber range of 516±10 cm ⁻¹ is compared as the Raman intensity derived from titanium oxide.
When rutile-type titanium oxide and anatase-type titanium oxide coexist, Raman intensity derived from rutile-type titanium oxide is used for comparison.

The printed material of the present embodiment preferably has a white non-printing area and a black printing area.
The non-printing area preferably has a brightness of No. 10 in the Munsell color system, that is, white. On the other hand, the printed area is preferably No. 0 to No. 8, more preferably No. 0 to No. 6, and even more preferably No. 0 to No. 4 in the Munsell color system.
In order to obtain the colors in the above Munsell color system, characteristics such as the thickness of the printing layer in the printing medium, the content of titanium oxide, and the irradiation conditions of the ultraviolet laser (e.g., average output, repetition frequency, wavelength, etc.) are appropriately adjusted. Adjusting is preferred.

<Irradiation conditions of ultraviolet laser>
The wavelength of the ultraviolet laser is preferably 370 nm or less, more preferably 365 nm or less, still more preferably 360 nm or less, and preferably 260 nm or more, more preferably 340 nm or more, from the viewpoint of improving the visibility of the printed area. More preferably, it is 350 nm or more.

The average output of the ultraviolet laser is preferably 0.3 W or more, more preferably 0.8 W or more, still more preferably 1.2 W or more, and even more preferably 1.8 W or more, from the viewpoint of improving the visibility of the printed area. And, from the viewpoint of economy, it is preferably 30 W or less, more preferably 25 W or less, still more preferably 20 W or less, even more preferably 15 W or less, still more preferably 10 W or less, and even more preferably 6 W or less.

The repetition frequency (frequency) of the ultraviolet laser is preferably 10 kHz or higher, more preferably 20 kHz or higher, still more preferably 30 kHz or higher, and preferably 100 kHz or lower, more preferably 100 kHz or higher, from the viewpoint of improving the visibility of the printed area. is 80 kHz or less, more preferably 60 kHz or less.

The spot diameter of the ultraviolet laser is preferably 10 μm or more, more preferably 20 μm or more, still more preferably 30 μm or more, and preferably 300 μm or less, more preferably 300 μm or less, from the viewpoint of obtaining a clear image and from the viewpoint of printability. It is 240 μm or less, more preferably 180 μm or less, further preferably 120 μm or less.

The scan speed of the ultraviolet laser is preferably 500 mm/sec or more, more preferably 1000 mm/sec or more, still more preferably 2000 mm/sec or more, and preferably 7000 mm/sec, from the viewpoint of high-speed printing and visibility of the printed area. sec or less, more preferably 6000 mm/sec or less, and even more preferably 5000 mm/sec or less.

The line pitch of the ultraviolet laser is preferably 10 μm or more, more preferably 20 μm or more, still more preferably 30 μm or more, and preferably 300 μm or less, from the viewpoint of obtaining a clear image and the availability of the device. It is more preferably 250 μm or less, still more preferably 200 μm or less.

<Aspect of method for manufacturing printed matter>
The printed matter manufacturing method of the present embodiment can be performed in various ways.
Various aspects to which the method for producing printed matter according to the present embodiment can be applied are illustrated below, but the method for producing printed matter according to the present embodiment is not limited to the following aspects. Although the information to be printed is not particularly limited, it is preferably variable information.
It is preferable that the printed matter manufacturing method of the present embodiment be performed in-line.
(1) Direct printing on the package The first embodiment of the method for producing printed matter of the present embodiment is a method for printing information on the package having the printing medium of the present embodiment. It has a process of printing directly on packages that are moving or intermittently stopped with an ultraviolet laser.
In the method for producing a printed matter of the first embodiment, a predetermined amount of titanium oxide is contained, a package is produced from the printing medium of the present embodiment, and printing is performed directly with an ultraviolet laser. At least the outermost layer of the package should be made of the printing medium of the present embodiment.
Examples of packaging bodies include food containers, and it is preferable to print directly on the side surface or the back surface of the packaging body with an ultraviolet laser.

(2) Printing on a Label A second embodiment of the printed matter manufacturing method of the present embodiment is a method of printing information on a label having a print medium of the present embodiment. It is sufficient that the printing medium constituting the printing surface of the label is made of the printing medium of the present embodiment.
The printed label is preferably applied to the package using a labeling machine. Various labeling devices have been proposed as labeling devices.
As a first labeling apparatus, a roll of label sheet is applied with an adhesive and then adhered to an article. More specifically, a cutting means for cutting a roll of label sheets into a predetermined length sheet by sheet, and a label sheet holder coated with an adhesive is used to hold the label sheets cut by the cutting means. Adhesive conveying means for receiving and adhering adhesive to the back surface of the label sheet, and pasting means for receiving the label sheet (label) to which adhesive is applied from the pasting conveying means and pasting it onto an article such as a container. As for the roll labeler, there is exemplified a roll labeler in which a rotary conveying means having a label holding surface on the outer surface is provided between the cutting means and the pasting conveying means.
In addition, a cutting means for cutting the roll-shaped label sheet one by one to a predetermined length, a delivery roll for transferring to the pasting roll, and a gluing roll for applying glue to the label sheet held by the pasting roll. Examples include a roll labeler having a roll labeler and an embodiment in which the delivery roll is not required.
The ultraviolet laser irradiation is preferably performed before cutting the roll-shaped label sheet into a predetermined length, or after cutting and before delivery to the next roll or the like. According to the mode of the roll labeler, the front side or the back side of the label sheet wound in a roll shape becomes the front side or the back side when attached to the package, so irradiation with an ultraviolet laser is performed accordingly.

A second labeling machine uses adhesive label rolls as labels.
When using an adhesive label roll with a release paper, for example, a release paper separation means for separating the adhesive label and the release paper, a delivery roll for receiving the adhesive label from which the release paper has been separated, and the adhesive label from the delivery roll A sticking device having a sticking roll that sticks to an article (package) by suction is exemplified. Irradiation with an ultraviolet laser is preferably carried out before the release paper is separated, or after the release paper is separated and before it is borne on the sticking roll.
In addition, it has a mechanism for setting an adhesive label roll with release paper, separating the adhesive label and the release paper, having a mechanism for attaching the label immediately after separation, and separating the release paper from the set adhesive label roll. An apparatus for printing with an ultraviolet laser is exemplified. The sticking method of the adhesive label described above is also called flow sticking.
Furthermore, it has a mechanism for setting an adhesive label roll with a release paper, separating the release paper from the adhesive label, and a mechanism for attaching the adhesive label to the article (package), and the mechanism for attaching is a syringe system. , air jet, or robot arm type labeling devices are exemplified. Irradiation with an ultraviolet laser is preferably performed until the release paper is separated from the set adhesive label roll with the release paper.

A linerless adhesive label may be used as the label. A linerless adhesive label is a label without release paper, and compared to the case of using an adhesive label roll with release paper, there are more labels per roll, and there is no release paper, so it is cheaper. have.
A label applying device using a linerless adhesive label includes a mechanism for setting a linerless label roll, a cutting mechanism for cutting the linerless label one by one, and the cut linerless label on an article (package). An apparatus having a sticking mechanism for sticking, wherein the sticking mechanism is a cylinder system or a robot arm system is exemplified. It is preferable that the printing by the irradiation of the ultraviolet laser is performed between the mechanism for setting the linerless label roll and the cutting mechanism, or while the cut linerless label is sent to the applying mechanism.

The third labeling device prints with an ultraviolet laser after the printing medium of the present embodiment is pasted on an article (packaging body).
As for the label application method, reference is made to the first and second devices described above.

(3) Printing on Adhesive Tape A third embodiment of the printed matter manufacturing method of the present embodiment is a mode in which the printing medium of the present embodiment is an adhesive tape.
That is, the method for producing a printed matter of the third embodiment has a step of attaching an adhesive tape made from the printing medium of the present embodiment to an article (package), and before the attaching step, or After the affixing step, there is a step of printing with an ultraviolet laser.
Also, a printing device in which a printing device using an ultraviolet laser is incorporated in a cardboard sealing machine may be used. Specifically, it has a mechanism for setting the adhesive tape winding, a conveyor for transporting the cardboard, a mechanism for folding the flap of the cardboard, and a mechanism for applying the adhesive tape to seal the cardboard. It has a mechanism for printing on the adhesive tape with an ultraviolet laser during or after the application.

The printed matter and the method for producing the printed matter of the present embodiment are not limited to the above-described aspects, and can be applied to various uses that require printing.

<Processed products using printing media and printed matter>
The ultraviolet laser printing medium of the present embodiment can be printed on by irradiating it with an ultraviolet laser, and can be used for various purposes.
The ultraviolet laser printing medium of the present embodiment and printed matter obtained by printing on the printing medium with an ultraviolet laser are used by being processed into various processed products.
Examples of the processed product using the ultraviolet laser printing medium of the present embodiment and printed matter obtained by printing on the printing medium with an ultraviolet laser include packages, labels, and adhesive tapes. It is also preferable to use the printing medium and printed material of the present embodiment by directly molding them into a package.
Examples of packaging include outer boxes; liquid containers for beverages such as milk cartons and paper cups (preferably liquid paper containers for beverages); food containers such as food trays and food cups (bowl-shaped); Examples of labels include label sheets, adhesive labels, and adhesive sheets, and examples of adhesive tapes include adhesive tapes and craft tapes.
By irradiating the surface of the package with an ultraviolet laser, it is possible to print characters, figures, and other images such as dates, barcodes, and various information related to the contents (contents, raw material names, contents amount, manufacturer name). is.

The characteristics of the present invention will be described more specifically below with reference to examples and comparative examples. The materials, amounts used, proportions, treatment details, treatment procedures, etc. shown in the following examples can be changed as appropriate without departing from the gist of the present invention. Therefore, the scope of the present invention should not be construed to be limited by the specific examples shown below. In the following examples, "%" and "parts" mean "% by mass" and "parts by mass" unless otherwise specified.

[Example 1]
(Manufacturing method of masterbatch)
In accordance with Japanese Patent Application Laid-Open No. 2015-96568, it was produced by the following procedure.
PE resin (polyethylene resin (LDPE), manufactured by Japan Polyethylene Co., Ltd., LC522) 60 parts and titanium oxide (manufactured by Ishihara Sangyo Co., Ltd., trade name R-780, rutile type titanium oxide, amorphous, average particle size 0.24 μm ( After mixing 40 parts with a tumbler mixer (manufactured by Eisin Co., Ltd., TM-65S) at 45 rpm for 1 hour, a twin-screw extruder (manufactured by Japan Steel Works, Ltd., TEX30XCT, L / D = 42) at a screw rotation speed of 250 rpm and a cylinder temperature of 200°C, extruded into strands, cooled in a water tank, and then pelletized using a pelletizer with an average shaft diameter of 2.0 mm and an average shaft length of 3.0 mm. A masterbatch was obtained by pelletizing into 0 mm columns.

(Lamination method)
The masterbatch and the PE resin were put into a single-screw extruder (manufactured by Toyo Seiki Seisakusho Co., Ltd., 50C150) so that the concentration of titanium oxide was the value shown in Table 1, and corona-treated paper (manufactured by Oji Materia Co., Ltd.) , OK ball, 310 g/m ² , thickness 386 μm, air permeability 13,500 seconds), the thickness of the resin-containing layer, which is the printed layer, is as shown in Table 1. It was quenched while being sandwiched between cooling rolls (manufactured by Kure Chrome Kogyo Co., Ltd., KRH120-2, line roughness Ra=0.4 μm) adjusted to 20° C. to obtain a printing medium having a laminate layer. The PE resin was melted at 320°C.

[Example 2]
A printing medium was obtained in the same manner as in Example 1, except that the cooling roll was changed to KRH120-3 manufactured by Kure Chrome Kogyo Co., Ltd., and the line roughness Ra was changed to 0.6 μm.

[Example 3]
A printing medium was obtained in the same manner as in Example 1, except that the cooling roll was changed to SKR80-4 manufactured by Kure Chrome Kogyo Co., Ltd. and line roughness Ra=2.9 μm.

[Example 4]
A printing medium was obtained in the same manner as in Example 1, except that the cooling roll was changed to a matte Duc manufactured by Kure Chrome Kogyo Co., Ltd. with a line roughness Ra of 5.0 μm.

[Examples 5 to 9]
A print medium was obtained in the same manner as in Example 2, except that the concentration of titanium oxide in the print layer was changed as shown in Table 1.

[Example 10]
A printing medium was obtained in the same manner as in Example 2, except that the PE resin in the laminate was changed to PP resin (polypropylene resin, PH943B manufactured by SunAllomer Co., Ltd.). The PE resin was changed to the PP resin in the same manner for the masterbatch. The PP resin was melted at 380°C.

[Example 11]
The procedure was the same as in Example 2, except that the rutile-type titanium oxide was changed to anatase-type titanium oxide (manufactured by Ishihara Sangyo Co., Ltd., A-100, average particle size: 0.15 μm (catalog value), shape: amorphous). to obtain a print medium.

[Example 12]
A printing medium was obtained in the same manner as in Example 2, except that a protective layer was provided.
(Method of providing protective layer)
A transparent resin (manufactured by Japan Polyethylene Co., Ltd., low-density polyethylene (LDPE), product name: LC522) is put into a single-screw extruder (manufactured by Toyo Seiki Seisakusho Co., Ltd., 50C150), and the thickness of the resin is 20 μm on the printed layer. After melting and laminating so that the A printing medium having a protective layer was obtained. Note that the melting was performed at 320°C.
The total light transmittance of the protective layer was 88.0%.

[Examples 13 to 15]
A printing medium was obtained in the same manner as in Example 2, except that the thickness of the printing layer was changed.

[Example 16]
A printing medium was obtained in the same manner as in Example 2, except that the base material was changed to the following paper base material.
(Manufacturing method of paper substrate)
15 parts of NBKP (bleached softwood kraft pulp) and 85 parts of LBKP (bleached broadleaf kraft pulp) are mixed and beaten so that the defibering freeness (CSF: Canadian standard freeness) is 500 mL to obtain a pulp slurry. rice field. To 100 parts of the pulp of the obtained pulp slurry, 0.55 parts (solid content conversion) of an amphoteric polyacrylamide-based paper strength agent (manufactured by Arakawa Chemical Industries, Ltd., Polystrone PS1260) as an internal paper strength agent. , As an internal sizing agent, 1.45 parts of rosin sizing agent (Size Pine N-771, manufactured by Arakawa Chemical Industries, Ltd.) (converted to solid content) and 2.5 parts of aluminum sulfate (converted to solid content) were added, and the surface layer was Five layers of paper stock were prepared for the outer layer, the outer layer, the middle layer, the inner layer, and the back layer. Using this stock, paper was made using a five-layer twin wire paper machine with a set basis weight of 60 g/m ² for all five layers. During the papermaking process ^, 0.7 g/ ^{m 2} of polyvinyl alcohol was applied by a size press and smoothed by a calender. A 400 second paper base was obtained.

[Example 17]
A printing medium was obtained in the same manner as in Example 16, except that a PE resin layer was provided on the opposite side of the printing medium prepared in Example 16 on which the printing layer was provided.
(PE resin layer)
A transparent resin (manufactured by Japan Polyethylene Co., Ltd., low-density polyethylene (LDPE), product name: LC522) is put into a single-screw extruder (manufactured by Toyo Seiki Seisakusho Co., Ltd., 50C150), and the printed layer is laminated on the opposite side of the paper. , After melt lamination so that the thickness of the resin is 20 μm, it is rapidly cooled while being sandwiched between cooling rolls (manufactured by Kure Chrome Industry Co., Ltd., KRH120-3, line roughness Ra = 0.6 μm) whose temperature is adjusted to 20 ° C. Thus, a printing medium having a resin layer on the opposite side of the paper substrate to which the printing layer was provided was obtained. The melting was performed at 320°C.

[Example 18]
(Method for preparing coating liquid)
Titanium oxide (manufactured by Ishihara Sangyo Co., Ltd., trade name R-780, rutile type titanium oxide, average particle size 0.24 μm (catalog value), irregular shape) 60 parts, ion-exchanged water 40 parts Mixed, poly as a dispersant 0.08 part of sodium acrylate was added to prepare a pigment dispersion using a Cowles dissolver. 18.1 parts of the pigment dispersion and 588 parts of a binder (Chemipearl S300, solid content 35%, manufactured by Mitsui Chemicals, Inc.) were mixed using a Cowles dissolver to give a solid content concentration of 36% and a titanium oxide concentration in the solid content of 5. % coating solution was prepared.

(Coating method)
Using an air knife coater, the prepared coating liquid was applied to a paper substrate (Oji Materia Co., Ltd., OK ball, 310 g/m ² , thickness 386 μm) so that the dry mass was 20 g/m ² . It is dried by passing through a drying zone set at 20°C, and rapidly cooled while being sandwiched between cooling rolls (manufactured by Kure Chrome Kogyo Co., Ltd., KRH120-2, line roughness Ra = 0.4 μm) whose temperature is adjusted to 20°C. , to produce print media.

[Example 19]
A printing medium was obtained in the same manner as in Example 18, except that the coating amount of the coating liquid was changed so as to have the thickness shown in the table.

[Example 20]
A printing medium was obtained in the same manner as in Example 2, except that the substrate was changed to a dry pulp nonwoven fabric (manufactured by Oji Kinocloth Co., Ltd., Kinocloth, basis weight: 40 g/m ² , thickness: 150 µm, air permeability: 1 second). .

[Comparative Example 1]
A printing medium was obtained in the same manner as in Example 1, except that the cooling roll was changed to a matte roll manufactured by Kure Chrome Kogyo Co., Ltd., and the line roughness Ra was 6.0 μm.

[Comparative Example 2]
A printing medium was obtained in the same manner as in Example 1, except that the cooling roll was changed to a 0.2S super mirror manufactured by Kure Chrome Kogyo Co., Ltd. and a line roughness Ra of 0.012 μm.

[Example 21]
(Method for preparing coating liquid)
As a solid content, titanium oxide (Ishihara Sangyo Co., Ltd., R-780, rutile type titanium oxide, average particle size 0.24 μm (catalog value), amorphous) 6.25 parts, calcium carbonate (Fimatec Co., Ltd., FMT -90, heavy calcium carbonate, average particle size 1.15 μm (catalog value)) 43.75 parts, kaolin (manufactured by Tiele, KAOFINE 90, average particle size 0.21 μm (catalog value)) 50 parts are mixed and dispersed. After 0.08 parts of sodium polyacrylate was added as an agent, deionized water was added to adjust the solid content concentration to 67.5%, and then a pigment dispersion was prepared using a Cowles dissolver.
Next, 16 parts of styrene-butadiene latex (Styronal ES7902 manufactured by BASF) was added as a solid content to 100 parts of the above pigment dispersion, and diluted with deionized water so that the solid content was 60%. Then, they were mixed using a Cowles dissolver to prepare a coating solution containing 5% titanium oxide, 35% calcium carbonate, 40% kaolin, and 20% styrene-butadiene latex as solids.

(Coating method)
The prepared coating solution is applied to the paper base material prepared in Example 16 so that the dry mass becomes 20 g/m ² using a blade coater, passed through a drying zone set at 130° C., and dried. A sheet substrate was obtained.

(Method of providing protective layer)
A transparent resin (manufactured by Japan Polyethylene Co., Ltd., low-density polyethylene (LDPE), product name: LC522) is put into a single-screw extruder (manufactured by Toyo Seiki Seisakusho Co., Ltd., 50C150), and the coating provided on the paper base material After melt-lamination on the layer so that the resin has a thickness of 15 μm, it is quickly cooled to 20° C. with a cooling roll (manufactured by Kure Chrome Industry Co., Ltd., KRH120-2, line roughness Ra = 0.4 μm). It was quenched while being sandwiched to obtain a printing medium having a protective layer on the coating layer. Note that the melting was performed at 320°C.

[Example 22]
A printing medium was obtained in the same manner as in Example 21, except that the cooling roll used when applying the protective layer was KRH120-3 manufactured by Kure Chrome Kogyo Co., Ltd., and the line roughness Ra was changed to 0.6 μm.

[Example 23]
A printing medium was obtained in the same manner as in Example 21, except that the cooling roll used when providing the protective layer was changed to matte Duc manufactured by Kure Chrome Kogyo Co., Ltd. and line roughness Ra=5.0 μm.

[Example 24]
(Method for preparing coating liquid)
A coating solution containing 1% titanium oxide, 39% calcium carbonate, 40% kaolin, and 20% styrene-butadiene latex as solids was prepared, and the coating amount was 10 g/m ² . A print medium was obtained in the same manner as in Example 22.

[Example 25]
(Method for preparing coating liquid)
A coating solution containing 15% titanium oxide, 25% calcium carbonate, 40% kaolin, and 20% styrene-butadiene latex as solids was prepared, and the coating amount was 20 g/m ² . A print medium was obtained in the same manner as in Example 22.

[Example 26]
(Method of providing protective layer)
A printing medium was obtained in the same manner as in Example 22, except that the protective layer was provided so that the thickness of the protective layer was 6 μm.

[Example 27]
(Method of providing protective layer)
A printing medium was obtained in the same manner as in Example 22, except that the protective layer was provided so that the thickness of the protective layer was 20 μm.

[Example 28]
(Method of providing protective layer)
A print medium was obtained in the same manner as in Example 22, except that the protective layer was provided so that the thickness of the protective layer was 50 μm.

[Example 29]
(Method of providing protective layer)
A print medium was obtained in the same manner as in Example 22, except that the protective layer was provided so that the thickness of the protective layer was 200 μm.

[Example 30]
(Method of providing protective layer)
A printing medium was obtained in the same manner as in Example 22, except that the resin used for the protective layer was changed to PP (polypropylene, manufactured by SunAllomer Co., Ltd., PH943B) and the melting temperature was changed to 380°C.

[Example 31]
(Method of applying printed layer)
Aqueous white ink for flexo (manufactured by Sakata Inx Co., Ltd., NP10 White SN-15 SP-3 PR-809, solid content concentration 68%, titanium oxide concentration in solid content 75%), medium (Sakata Inx Co., Ltd.) , NP10 PP-F, solid content 25.0%, titanium oxide concentration 0% in solid content) Diluted with 1768 parts, solid content concentration 27.3%, titanium oxide concentration 10% in solid content Coating A liquid was prepared. Thereafter, printing was performed on a cardboard liner (Oji Materia Co., Ltd., OFK-EM, grammage: 170 g/m ² , thickness: 200 μm) using a 150 line/inch anilox roll with a center drum type flexo printing machine. In order to secure the coating amount, printing was performed twice under the same conditions. The coating amount after drying was 2.0 g/m ² and the coating amount of titanium oxide was 0.2 g/m ² .
(Method of providing protective layer)
Thereafter, a protective layer was provided in the same manner as in Example 22 to obtain a printing medium.

[Example 32]
(Method of applying printed layer)
100 parts of water-based white ink for flexo (manufactured by Sakata Inx Co., Ltd., NP10 White SN-15 SP-3 PR-809, titanium oxide concentration 75% in solid content), medium (manufactured by Sakata Inx Co., Ltd., NP10 PP-F, solid 25.0% solid content, 0% titanium oxide concentration in the solid content) was diluted with 136 parts to prepare a coating liquid with a solid content concentration of 43.2% and a titanium oxide concentration of 50% in solid content. A 150 line/inch anilox roll was used on a center drum type flexo printing machine to print on a cardboard liner (OFK-EM manufactured by Oji Materia Co., Ltd., basis weight 170 g/m ² ).
The coating amount after drying was 2.5 g/m ² and the coating amount of titanium oxide was 1.3 g/m ² .
(Method of providing protective layer)
Thereafter, a protective layer was provided in the same manner as in Example 22 to obtain a printing medium.

[Example 33]
(Method of applying printed layer)
A gravure printing solvent-based white ink (Gratone PCN, manufactured by Sakata Inks Co., Ltd., titanium oxide concentration of 60% in solid content) was applied to the paper base prepared in Example 16 using a gravure roll with a plate depth of 200 μm with a gravure printing machine. printed on the material. The coating amount after drying was 4 g/m ² and the coating amount of titanium oxide was 2.4 g/m ² .
(Method of providing protective layer)
Thereafter, a protective layer was provided in the same manner as in Example 22 to obtain a printing medium.

[Example 34]
OK Ball, 310 g/m ² , thickness 386 μm, air permeability 13,500 seconds, manufactured by Oji Materia Co., Ltd., was used as the paper base material, except that the printed layer was applied to the coat layer side of the paper base material. A printing medium was obtained in the same manner as in Example 22.

[Example 35]
A printing medium was obtained in the same manner as in Example 22, except that OK Frace Pro, 310 g/m ² , thickness 350 μm, and air permeability 47,000, manufactured by Oji Materia Co., Ltd., was used as the paper substrate.

[Example 36]
(Method for preparing coating liquid)
A coating liquid containing 10% titanium oxide, 30% calcium carbonate, 40% kaolin, and 20% styrene-butadiene latex as solids was prepared. Thereafter, a printing medium was obtained in the same manner as in Example 22, except that drying and coating were carried out so that the coating amount was 48 g/m ² .

[Example 37]
A print medium was obtained in the same manner as in Example 31, except that the titanium oxide was diluted with a medium (NP10 PP-F manufactured by Sakata Inx Co., Ltd.) so that the solid content concentration of titanium oxide was 2%.

[Comparative Example 3]
A printing medium was obtained in the same manner as in Example 21, except that the cooling roll was changed to 0.2S Super Mirror manufactured by Kure Chrome Kogyo Co., Ltd. and line roughness Ra=0.012 μm.

[Comparative Example 4]
A printing medium was obtained in the same manner as in Example 21, except that the cooling roll was changed to a matte roll manufactured by Kure Chrome Kogyo Co., Ltd. with a line roughness Ra of 6.0 μm.

[Measurement and Evaluation]
The following measurements and evaluations were performed on the obtained medium for ultraviolet laser printing.
[Arithmetic mean roughness]
The printing media obtained in Examples and Comparative Examples were cut into a size of 50 mm×50 mm to obtain a test piece.
Using a digital microscope (manufactured by KEYENCE CORPORATION, model number: VHX8000), a depth-stacked image of the test piece was obtained. A depth stacking image is an image obtained by moving the focal length to obtain a plurality of images, extracting the in-focus portion from each image, and constructing one image. Focus stacking images were acquired using the live focus stacking function installed in the digital microscope.
After that, using the line roughness (Ra) measurement function, the arithmetic average roughness Ra was calculated from the obtained micrograph.
The following conditions were used in line roughness measurement mode.
・Magnification at the time of micrograph acquisition: 700 times ・Setting of profile line: A profile line was arbitrarily selected between two points in the obtained photograph, and the profile line was set so that the evaluation length was 383 μm.
・Measurement type: Roughness ・Cutoff value: λs = None ・Cutoff value: λc = None ・Double Gaussian filter: OFF
· Correction of the extreme effect: Yes Five arbitrary points on the test piece were measured in the same manner, and the average value of the measured arithmetic average roughness Ra was adopted.

[Air Permeability]
(Preparation of test piece)
1. When the Printed Layer is a Laminate Layer A trigger point for peeling was created with a cutter, and the laminate layer, which is the printed layer, was peeled from the paper while pulling the trigger point by hand. After that, it was cut into 60 mm squares and used as test pieces.
When peeling the laminate layer from the paper, if the surface of the paper is pulled by the laminate layer and torn, use a grinding device (manufactured by Sagawa Seisakusho Co., Ltd., grindstone dimensions φ 50.8 mm × 12.7 mm) to remove the laminate layer. After removing the chisel, it was cut into a 60 mm square to obtain a test piece.

2. When the printed layer is the coating layer 2-1. When a non-printable area is included in the print medium In the non-printable area, create a notch with a cutter to trigger peeling. peeled off from the paper.
After that, it was cut into 60 mm squares and used as test pieces.
When peeling the protective layer from the paper, if the surface of the paper is pulled by the protective layer and torn, use a grinding device (manufactured by Sagawa Seisakusho Co., Ltd., grindstone dimensions φ 50.8 mm × 12.7 mm) to remove the protective layer. After removing the chisel, it was cut into a 60 mm square to obtain a test piece.
2-2. When the printing medium does not include a non-printable area: A cut was made at the triggering site for peeling with a cutter, and the protective layer was peeled off from the paper while pulling the triggering site by hand. After that, only the printed layer, which is the coating layer, was removed using the grinding machine, and cut into 60 mm squares to obtain test pieces.
When peeling the protective layer from the paper, if the surface of the paper is pulled by the protective layer and torn, after removing the protective layer and the coating layer (printing layer) using the grinding device, cut into 60 mm squares. It was cut into test pieces.

(Measurement of air permeability)
Air permeability was measured by the Oken type tester method described in JIS P 8117. Apparatus: Digital type Oken type air permeability/smoothness tester (manufactured by Asahi Seiko Co., Ltd., EYBO)
Nozzle: For measuring high air permeability 5 randomly selected locations were used for measurement, and the average value of the 5 measurements was taken as the measured value.
The air permeability was measured from the surface on which the printed layer was provided.

[Amount of titanium oxide]
1. When the printed layer is a laminate layer <Pretreatment>
A pretreatment was performed to separate the laminate layer, which is the printed layer, from the substrate. A printable region cut out to an appropriate size was immersed in a copper ethylenediamine solution for measuring cellulose viscosity (manufactured by Merck) for 3 hours, then the laminate layer was peeled off from the paper substrate and thoroughly washed with deionized water. . After that, the moisture on the laminate layer was wiped off and dried in a drier at 60° C. for 1 hour to obtain a laminate layer to be tested for measurement.
Moreover, the cut test piece was cut out so that the area could be calculated, and the calculated area was applied to the below-mentioned formula.
<Preparation of test piece>
The pretreated laminate layer was cut into a suitable size to obtain a sample (test piece), and the cut area and weight were recorded.
<Dissolution of test piece>
A mixed solvent of nitric acid: hydrofluoric acid = 50:5 (% by volume) and a test piece were put into a Teflon (registered trademark) container of an autoclave device (CEM Japan, MARS5), and autoclaved at 210 ° C. for 120 minutes. , dissolved the specimen. The mass of the test piece may be changed as appropriate, and when the test piece remains undissolved, the ratio of nitric acid and hydrofluoric acid, the treatment temperature, the treatment time, etc. may be changed as appropriate.
After dissolving the test piece, the volume was accurately adjusted using ultrapure water. If undissolved matter remains, the ratio of nitric acid and hydrofluoric acid may be changed.

<Measurement of amount of titanium oxide in solution>
(1) ICP apparatus and measurement conditions are as follows.
ICP device: ICP-OEC device (manufactured by Rigaku Corporation, CIROS1-20)
Measurement condition:
・Carrier gas: argon gas ・Argon gas flow rate 0.9 L/min
・Plasma gas flow rate 14L/min
・Plasma output 1400W
・Pump speed: 2
・Measurement wavelength Ti: 334.941 nm
(2) Preparation of calibration curve A general-purpose mixed standard solution (SPEX, XSTC-622B) is accurately measured so as to have the following concentrations, and is subjected to measurement under the above measurement conditions, corresponding to the emission wavelength of titanium atoms. The intensity at 334.941 nm was measured.
・ Concentration for calibration curve creation: 0 ppm, 0.01 ppm, 0.05 ppm, 0.1 ppm, 0.5 ppm, 1.0 ppm, 3.0 ppm, 5.0 ppm
(3) Measurement of Titanium Oxide Content in Dissolved Solution The solution in which the test piece was dissolved was diluted with ultrapure water so as to fall within the above calibration curve, and was subjected to ICP measurement.
(4) Titanium oxide content calculation method The titanium oxide content was calculated by the following formula. Incidentally, the molecular weight of titanium oxide÷the molecular weight of titanium≈1.669.
Titanium oxide content (g/m ² ) = ICP measurement concentration (ppm) x dilution factor x constant volume (L) x 1.669 x 1000/area (m ² )

2. When the printed layer is the coating layer 2-1. When the non-printable area is included in the print medium <Preparation of test piece>
A printable region and a non-printable region (region where no coating layer is provided) of the printing medium were cut out to an appropriate size to obtain a sample (test piece), and the cut out area was recorded.
<Dissolution of test piece>
A mixed solvent of nitric acid: hydrofluoric acid = 50: 5 (% by volume) and a test piece were put into a Teflon (registered trademark) container of an autoclave device (CEM Japan, MARS5), and autoclaved at 210 ° C. for 120 minutes. , dissolved the specimen. The area of the test piece may be changed as appropriate, and when the test piece remains undissolved, the ratio of nitric acid and hydrofluoric acid, the treatment temperature, the treatment time, etc. may be changed as appropriate.
After dissolving the test piece, the volume was accurately adjusted using ultrapure water.

<Measurement of amount of titanium oxide in solution>
(1) ICP apparatus and measurement conditions are as follows.
ICP device: ICP-OEC device (manufactured by Rigaku Corporation, CIROS1-20)
Measurement condition:
・Carrier gas: argon gas ・Argon gas flow rate 0.9 L/min
・Plasma gas flow rate 14L/min
・Plasma output 1400W
・Pump speed: 2
・Measurement wavelength Ti: 334.941 nm
(2) Preparation of calibration curve A general-purpose mixed standard solution (SPEX, XSTC-622B) is accurately measured so as to have the following concentrations, and is subjected to measurement under the above measurement conditions, corresponding to the emission wavelength of titanium atoms. The intensity at 334.941 nm was measured.
・ Concentration for calibration curve creation: 0 ppm, 0.01 ppm, 0.05 ppm, 0.1 ppm, 0.5 ppm, 1.0 ppm, 3.0 ppm, 5.0 ppm
(3) Measurement of Titanium Oxide Content in Dissolved Solution The solution in which the test piece was dissolved was diluted with ultrapure water so as to fall within the above calibration curve, and was subjected to ICP measurement.
(4) Titanium oxide content calculation method The titanium oxide content was calculated by the following formula. Incidentally, the molecular weight of titanium oxide÷the molecular weight of titanium≈1.669.
Titanium oxide content (g/m ² ) = ICP measurement concentration (ppm) x dilution factor x constant volume (L) x 1.669 x 1000/area (m ² )
The content of titanium oxide in the coating layer was obtained by subtracting the content of titanium oxide in the non-printable region from the content of titanium oxide in the printable region.

2-2. When the non-printable area is not included in the print medium <Preparation of test piece>
Two sheets of printing medium were cut into appropriate sizes, and the cut area was recorded.
One of the cut test pieces was used as a reference sample by scraping off the protective layer and the coating layer using a grinder (made by Sagawa Seisakusho Co., Ltd., whetstone dimensions φ50.8×12.7 mm).
The cross section was appropriately observed using an electron microscope so as not to excessively scrape off.
<Subsequent processing>
2-1. , and the difference in titanium oxide content between the two sheets was taken as the titanium oxide content of the coating layer.

[Thickness of printed layer and protective layer]
The thickness of the resin layer was measured from image data obtained from a scanning electron microscope.
(1) Preparation of Measurement Sample A sample was embedded in a photocurable resin (D-800, manufactured by Toagosei Co., Ltd.), and a section of the print medium was taken out with an ultramicrotome. A diamond knife was used for cutting, and cutting was performed at room temperature.
The cut section was subjected to gold vapor deposition to a thickness of about 20 nm and tested for measurement with a scanning electron microscope.
(2) Measuring device and conditions Measuring device: S-3600 (manufactured by Hitachi High-Tech Co., Ltd.)
Measurement conditions: magnification of 2000 times The type of scanning microscope is not limited to the above, but a device that displays a scale bar is used. If the printed layer or protective layer is thin, select an appropriate magnification to acquire the image data.
(3) Measurement method Using an energy dispersive X-ray spectrometer attached to the scanning electron microscope, after confirming that the printed layer to be observed contained titanium element, image data was acquired at a magnification of 2000. After printing the obtained image data on a printing medium, the thickness of the target printing layer (the length of the boundary from the boundary with other layers) was measured with a ruler, and the thickness of the actual printing layer was compared with the scale bar. Thickness was measured. Acquire image data of 5 randomly selected locations from one measurement sample, measure the thickness of the thickest and thinnest locations of the printed layer from the image data of one location, and calculate the average of 10 locations as the coating layer. The thickness of
Moreover, in the case of having a protective layer on the printed layer, the thickness of the protective layer was measured by the same method.

[Total light transmittance of protective layer]
(Preparation of test piece)
A pretreatment was performed to separate the protective layer. Only the depth of the protective layer of the printable area cut to a suitable size was cut with a single-bladed utility knife. Next, starting from the cut, the protective layer was manually peeled off and separated. When inorganic pigments or pulp fibers adhered to the obtained protective layer, it was immersed in a copper ethylenediamine solution for cellulose viscosity measurement (manufactured by Merck & Co.) for 3 hours and then thoroughly washed with deionized water. After that, the moisture on the protective layer was wiped off and dried in a drier at 60° C. for 1 hour to obtain a protective layer to be tested for measurement. If the protective layer can be separated by immersion in a copper ethylenediamine solution, the manual separation step using a cutter knife may be omitted.
After that, the total light transmittance of the protective layer was measured according to JIS K 7361-1:1997.

[Evaluation of visibility (gloss)]
The ultraviolet laser printing media obtained in Examples and Comparative Examples were cut into MD: 60 mm×CD: 110 mm to obtain test pieces. Character strings (1) and (2) were printed on the test piece using an ultraviolet laser irradiation machine (manufactured by Keyence Corporation, model number: MD-U1020C) under the following conditions.
・Wavelength: 355 nm
・Output: 80% (2.5W at 100% output)
・Frequency: 40 kHz
・Spot diameter: 40 μm (at the time of focusing)
・Spot variable: 40
・Paint interval: 0.04mm
・Scan speed: 3000mm/sec
・Character string (1): A to Z in MSP Gothic (26 characters, height 3mm, width 66.8mm)
・ Character string (2): MSP Gothic (13 characters, height 3 mm, width 64.7 mm)
A horizontally long LED light (manufactured by Panasonic Corporation, SQ-LC520) was used as a light source, and characters on a test piece tilted at 45° with respect to the light source were read and evaluated according to the following criteria.
A: The printing is visible in black and the content of the printing is easily visible. B: The printing is dark gray and the content of the printing is also easily visible. C: The printing is visible in light white. , The printed content can be visually recognized D: The printed content is visible in pale white, and it takes time to visually recognize the printed content If the printed matter is glossy, the LED light will be reflected, making it difficult to see the printed content.

[Print Density]
The ultraviolet laser printing media obtained in the examples and comparative examples were cut into MD: 50 mm×CD: 50 mm to obtain test pieces. A 10 mm × 10 mm square was printed on the surface of the test piece using an ultraviolet laser irradiation machine (manufactured by Keyence Corporation, model number: MD-U1020C).
The following conditions were used for printing.
・Wavelength: 355 nm
・Output: 80% (2.5W at 100% output)
・Frequency: 40 kHz
・Spot diameter: 40 μm (at the time of focusing)
・Spot variable: 40
・Paint interval: 0.04mm
・Scan speed: 3000mm/sec
Using a printed square of 10 mm, the density of the printed area was measured with a Macbeth densitometer and evaluated according to the following criteria.
A: measured value is 0.40 or more B: measured value is 0.30 or more and less than 0.40 C: measured value is 0.20 or more and less than 0.30 D: measured value is less than 0.20 In addition, measured value is 0 When the measured value is 0.40 or more, the image density of the print is high and is easily visible, and when the measured value is 0.30 or more and less than 0.40, the image density of the print is slightly low, but the printed content can be visually recognized. . Also, when the measured value is 0.20 or more and less than 0.30, the image density of the print is low, but the printed content is somehow visible, and when the measured value is less than 0.20, the image density of the print is Too thin to see printed content.

[Printability]
The ultraviolet laser printing media obtained in Examples and Comparative Examples were cut into MD: 40 mm×CD: 400 mm. The cut sample was solid printed under the following conditions using a gravure printing suitability tester (manufactured by Kumagai Riki Kogyo Co., Ltd.).
(Printing conditions)
・Ink: Safe WH process black (manufactured by DIC)
• Viscosity: 18 seconds using a Zahn viscometer (type 417 No. 3). If it exceeds 18 seconds, dilute with a mixed solvent of (water/isopropanol=3:7).
・Printing pressure: 30 kg/cm ²
・Speed: 60m/min
(evaluation)
The printed finish was visually observed and judged according to the following criteria.
A: There is no uneven ink application, and the printing finish is good.
B: There is almost no uneven ink application, and there is no practical problem.
C: Slightly uneven ink application, but no practical problem.
D: There is a large amount of ink application unevenness, which poses a practical problem and is extremely inferior in quality.

[Smoothness after printing]
The ultraviolet laser printing media obtained in Examples and Comparative Examples were cut into MD: 50 mm×CD: 100 mm. The characters "2021 (font: Arial, width: 9 mm, height 3 mm)" were printed on the surface of the cut sample using an ultraviolet laser irradiation machine (manufactured by Keyence Corporation, model number: MD-U1020C).
The following conditions were used for printing.
・Wavelength: 355 nm
・Output: 80% (2.5W at 100% output)
・Frequency: 40 kHz
・Spot diameter: 40 μm (at the time of focusing)
・Spot variable: 40
・Paint interval: 0.04mm
・Scan speed: 3000mm/sec
(evaluation)
Using a surface roughness meter (manufactured by Keyence Corporation, model number: VR-3000), the difference in height between the non-printing area and the printing area was measured and judged according to the following criteria. The following conditions were used for the measurement.
・Observation magnification: 12 times ・Region designation as reference plane setting: continuous region (extraction method: plane, tolerance level: 4, degree of expansion/contraction: 3)
・Surface shape correction: waviness removal (correction strength 5)
・Measurement type: line roughness ・Cutoff value: λs = none ・Cutoff value: λc = none 30 μm or more and less than 45 μm D: Height difference is 45 μm or more

[Raman intensity ratio]
<Preparation of test piece>
A print sample similar to that prepared in [Print Density] was obtained.

<Measurement conditions>
The measurement conditions for the Raman intensity ratio are as follows, but if the printed matter is damaged by the laser used for measurement, or if the fluorescence is strong, etc., the following measurement conditions such as laser output and irradiation time should be adjusted accordingly. can be changed. However, values measured under the same conditions are used for the Raman intensities of the printed area and the non-printed area.
・Apparatus: inVia Raman microscope QUONTOR manufactured by Renishaw
・Excitation laser: 532 nm
・Laser power: 50mW (at 100% output)
・Laser output: 5%
・Measurement mode: confocal mode ・Irradiation time: 2.0 sec
・Number of accumulated times: 10 times ・Laser spot diameter: 2.5 μm
・Objective lens: 20x

<Measurement method>
Measurement was performed by the following method.
(1) A standard sample (single crystal silicon, manufactured by Renishaw) was used to calibrate the Raman shift position (520.5 cm ⁻¹ of single crystal silicon).
(2) A sheet-like sample was placed on a sample table. Pressers were installed as necessary to keep the sheet flat.
(3) Observation was performed by adjusting the focus with the device (setting the simulated laser so that the focus was the smallest). When measuring the printed area, the blackest part that can be visually confirmed was measured so that it was positioned at the center of the guide displayed at the time of measurement. When measuring the non-printing area, the measurement was performed with a distance of 300 μm or more from the printing area.

As shown in Table 1, it has a substrate and a printed layer containing titanium oxide laminated adjacent to the substrate, the outermost layer of the ultraviolet laser printed surface is a resin layer, and the outermost layer By directly printing a printing medium having an arithmetic surface roughness (Ra) of 0.3 μm or more and 6.0 μm or less with an ultraviolet laser, a printed matter having excellent visibility and excellent printability was obtained. .
On the other hand, the printing media of Comparative Examples 2 and 3, in which the arithmetic surface roughness (Ra) of the surface of the outermost layer was less than 0.3 μm, were highly glossy and did not provide sufficient visibility. Moreover, the print media of Comparative Examples 1 and 4, in which the arithmetic surface roughness (Ra) of the surface of the outermost layer exceeded 6.0 μm, were inferior in printability.

The medium for ultraviolet laser printing of the present invention can provide a printed matter with excellent visibility by discoloring titanium oxide when irradiated with an ultraviolet laser, and further has excellent printability. The medium for ultraviolet laser printing and the printed material of the present invention are suitably applied to processed products such as packages, labels, and adhesive tapes on which variable information such as dates and bar codes are printed. Furthermore, the method for producing printed matter of the present invention is suitably applied to printing variable information on packages, labels, adhesive tapes, and the like.

100 printing medium 10 substrate 20 printing layer 30 protective layer

Claims (9)

Having a base material and a printed layer containing titanium oxide laminated adjacent to the base material,
The base material is a paper base material,
The base material has an air permeability of 30,000 seconds or less,
The outermost layer of the ultraviolet laser printed surface is a layer containing a resin,
The arithmetic surface roughness (Ra) of the surface of the outermost layer is 0.3 μm or more and 6.0 μm or less.
Medium for UV laser printing. The medium for ultraviolet laser printing according to claim 1, wherein the content of titanium oxide in the print layer is 0.04 g/ ^m2 or more and 10.0 g/ ^m2 or less. 3. The medium for ultraviolet laser printing according to claim 1 , wherein the air permeability of said substrate is 15,000 seconds or less. The ultraviolet laser printing medium according to any one of claims 1 to 3 , wherein the printing layer is a laminate layer containing titanium oxide or a coating layer containing titanium oxide. The ultraviolet laser printing medium according to any one of claims 1 to 4 , wherein the print layer has a thickness of 1.0 µm or more and 60 µm or less. 6. The medium for ultraviolet laser printing according to claim 1 , wherein said print layer is a layer containing said resin. Having a protective layer on the printed layer,
The medium for ultraviolet laser printing according to any one of claims 1 to 5 , wherein the protective layer is a layer containing the resin. A printed matter obtained from the ultraviolet laser printing medium according to any one of claims 1 to 7 ,
The printed layer has, at least in part, a printed region containing discolored titanium oxide,
The ratio of the Raman intensity derived from titanium oxide in the printed region to the Raman intensity derived from titanium oxide in the non-printed region is 0.70 or less.
printed matter. A processed product using the ultraviolet laser printing medium according to any one of claims 1 to 7 or the printed matter according to claim 8 .

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