JP2008255132A - Active energy ray-curable ink printing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an active energy ray-curable ink composition comprising five colors of yellow, red, indigo blue, black and green and being excellent in color reproducibility of high chroma. <P>SOLUTION: This active energy ray-curing type ink composition using two, three or four of a yellow ink, a red ink, an indigo blue and a green ink, and a black ink is characterized in that the four colors of yellow, red, indigo blue and green comprise a combination of a yellow ink containing a disazoyellow-based compound as a pigment component, a red ink containing a metal lake compound of a rhodamine-based dye as a pigment component, an indigo blue ink containing a phthalocyanine-based compound as a pigment component, and a green ink containing a halogenated phthalocyanine-based compound as a pigment component. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an active energy ray curable ink composition comprising five colors of yellow, red, indigo, black, and green, and relates to an active energy ray curable ink composition excellent in high color reproducibility.

  The IT revolution that began in the 1990s has led the environment surrounding the printing site to the direction of digitalization. By this digitization, workflow of conventional printing methods (photographing, positive, scanning, data, design, EPS)・ Imposition, film, printing plate, printing) was a multi-stage process, but we succeeded in dramatically shortening the process with digital camera shooting, DTP, CTP, and printing. As a result, “RGB” conversion of the submitted data is being standardized, and the current situation is that the data to be handled is shifting to a wider color reproduction region.

  However, lithographic offset printing consisting of four process colors (CMYK) of yellow, red, indigo, and black, which is currently the mainstream, has a hue due to subtractive color mixing. In addition, the color reproduction area becomes narrower than that of RGB, and the difference in color reproducibility between digital data and printed matter has become a problem. In particular, when yellow ink, which is generally printed as the final color of printing, is opaque, it causes yellow fogging and has a large effect on each color of underprinting. Therefore, yellow ink must be as transparent as possible. Desirably, it is desirable to obtain secondary and tertiary colors without turbidity when overprinted with other colors.

As a means for solving this, in general lithographic offset printing, in Patent Document 1, a printing method using an ink set of 6 to 7 colors is established as a high-saturation printing system, and ink sets having respective specified hues are established. As printing methods to be used, six colors (hexachrome printing) in which orange and green are added to four process colors, seven colors (high fidelity printing) in which orange, green, and purple are added to four process colors have been established. In addition, as represented by hexachrome ink, there are also methods such as adding fluorescent pigments to some colors as a means of suppressing the turbidity of not only primary colors but also secondary and tertiary colors and expanding the color reproduction range. However, there are also disadvantages such as deterioration of printability (transfer defects, gloss reduction, etc.) and fading of printed matter due to insufficient light resistance. Furthermore, the number of ink colors used is 6 or 7, and an expensive multicolor printing machine with 6 or more printing cylinders is required. It is an indispensable condition, and it is limited to using this system due to huge capital investment and complicated color management to start a new one. In addition, similar attempts have recently been investigated for ultraviolet curable inks.
JP 2001-260516 A

  The present invention has been made in order to solve such problems in the prior art, and the problem is that the reproducible color rendering region (gamut) is superior to the ISO standard Japan color compliant ink. Active energy ray curable ink that can reproduce the color area closer to the color reproduction area of "RGB" by adding green ink to the four colors of yellow, red, indigo, and black and performing five-color printing. Is to provide.

  In general, in order to widen the color reproduction region, it is necessary to approximate the ideal spectral reflectance curve of each color.

  That is, the wavelength range in which a person recognizes color is 400 nm to 700 nm light (this wavelength is referred to as visible light), and the reflection spectrum of each ink is 100% for yellow ink in the wavelength range of 500 nm to 700 nm. The reflectance in the wavelength region of 400 nm to 500 nm is 0%, and the red ink has a reflectance of 100% in the wavelength region of 400 nm to 500 nm and 600 nm to 700 nm, and the reflectance in the wavelength region of 500 nm to 600 nm. It is 0%, and indigo ink is said to be ideal that the reflectance in the wavelength region of 400 nm to 600 nm is 100% and the reflectance in the wavelength region of 600 nm to 700 nm is 0% (ideal Is shown in FIG. 3).

  However, the reflection spectrum of yellow, red, indigo, and black ink compositions composed of four process colors currently used is far from the ideal reflection spectrum. Since there is unnecessary absorption in the part that must be completely reflected, a turbid component of the ink exists, and the color reproducibility is narrowed.

  That is, the present invention relates to an active energy ray-curable printing ink composition comprising five colors of yellow, red, indigo, black, and green, wherein four colors of yellow, red, indigo, and green are disazo yellow compounds as pigment components. A yellow ink, a red ink having a rhodamine dye metal lake compound as a pigment component, an indigo ink having a phthalocyanine compound as a pigment component, and a green ink having a halogenated phthalocyanine compound as a pigment component. The present invention relates to an active energy ray-curable ink composition.

  In addition, the present invention contains CI Pigment Yellow 12 or CI Pigment Yellow 13 as a disazo yellow-based compound in an amount of 1.20 to 2.5 on black ink having an L * value of 6.0 to 8.0. The present invention relates to the above-described yellow ink having transparency that does not exceed 12.0 when the L * value is overprinted in the range of 00.

  The present invention also relates to the above-mentioned red ink containing 15 to 30% of C.I. Pigment Red 81 or C.I. Pigment Violet 1 as a metal lake compound of a rhodamine dye.

The present invention also provides the indigo dye as described above, comprising 10 to 25% of CI Pigment Blue 15: 3 or CI Pigment Blue 15: 4 and 0.5 to 2.0% of CI Pigment Green 7 as the phthalocyanine compound. It relates to ink.
The present invention also provides C.I. as a halogenated phthalocyanine compound. I. Pigment green 7 or C.I. I. The present invention relates to the above green ink containing 15 to 30% of Pigment Green 36.

  By using the active energy ray curable ink composition provided by the present invention, it is expressed by 6 colors and 7 colors printing in which orange, green, purple, etc. are added in addition to the conventional yellow, red, indigo and black ink processes. It is possible to reproduce the RGB color reproduction area that has been made with five colors of yellow, red, indigo, black, and green. Further, in the present invention, since a fluorescent pigment is not used as a means for improving the color reproduction region of the printed material, a highly saturated printed material can be obtained without deteriorating printability, fading with time of the printed material, and the like.

  Next, the present invention will be described more specifically with reference to preferred embodiments.

  Next, the present invention will be described more specifically with reference to preferred embodiments.

  The present invention is a pigment dispersant such as an aluminum chelate, if necessary, containing a pigment, a synthetic resin, a photopolymerization initiator, a monomer having an ethylenically unsaturated double bond, and an oligomer having an ethylenically unsaturated double bond. , An active energy ray curable ink consisting of four colors, yellow, red, indigo and black, obtained by adding an auxiliary agent such as an anti-friction agent, and ISO standard Japan color standard paper such as Mitsubishi Paper ( Printed on "Tokuhishi Art Double Sided 46th Edition / 110kg" manufactured by Co., Ltd., and when yellow, red, and indigo were measured with a Gretag Macbeth D196 densitometer, the density value was 1.40 to 1.44 for yellow. When red is 1.52 to 1.56, indigo is 1.63 to 1.67, and green is indigo density within the range of 1.60 to 2.70 (reference density value) Chromaticity of L * a * b * color system for single color overprint, and C value is yellow ink, L *: 84 to 92, preferably 85 to 90, a *: -3 to -11, preferably -4 to -9, b *: 90 to 100, preferably 93 to 99 C: 92-100, red ink, L *: 48-55, preferably 49-54, a *: 77-85, preferably 78-83, b *: -14 to -20, preferably -16 to -20, C: 80 to 86, indigo ink, L *: 52 to 58, preferably 52 to 57, a *: -38 to -43, preferably -39 to -42, b *: -46 to- 54, preferably -47 to -52, C: 61 to 66, green ink L *: 50 to 65, preferably 50 to 62, a *: -70 to -85, preferably -70 to -82, b *: −3 to 5, preferably −3 to −3, C: 70 to 82, and further, red ink × yellow ink, L *: 50 to 55, a *: 6 9 to 74, b *: 54 to 59, C: 87 to 94, L *: 17 to 23, a *: 51 to 46, b *: −71 to −76 C: 85-91, indigo ink × green ink, L *: 33-43, a *: −58 to −73, b *: −15 to −30, C: 67 to 73, yellow ink × When green ink is overprinted, L *: 46 to 60, a *: −73 to −85, b *: 40 to 57, and C: 90 to 95.

  Furthermore, each of these (a) yellow, (b) red, and (c) indigo is related to an ink in which the reflection spectrum of the spectral reflection curve of the solid-colored 100% solid portion satisfies the following range conditions.

  (A) Yellow has a relative reflection intensity of 0 to 10% in the wavelength region of 400 nm to 480 nm and 80 to 100 in the wavelength region of 550 nm to 700 nm when the total reflection is 100% in the wavelength region of 400 nm to 700 nm. A yellow ink having a% reflection spectrum.

  (B) When the total reflection is 100% in the wavelength region of 400 nm to 700 nm, the maximum reflectivity in the wavelength region of 400 nm to 500 nm is 35% to 100%, and in the wavelength region of 500 nm to 560 nm. A red ink having a reflectance spectrum of 0 to 10%, a reflectance of 630 to 700 nm and a reflectance spectrum of 70 to 100%.

  (C) Indigo has a maximum reflectance of 50 to 100% in the wavelength region of 400 nm to 530 nm and a reflectance of 0 to 10 in the wavelength region of 400 nm to 530 nm when the total reflection is 100% in the wavelength region of 400 nm to 700 nm. An indigo ink having a reflection spectrum of%.

As a method for expressing the color reproduction area, an XYZ color system (CIE1931 color system), an X10Y10Z10 color system (CIE1964 color system), an L * a * b * color system (CIE1976), a Hunter Lab color system, Munsell color system, L * u * v * color system (CIE1976), and the like.
In the L * a * b * color system, “brightness” is expressed by L * as the degree of brightness that can be compared regardless of hue, and indicates that the color becomes brighter as L * increases and becomes darker as it decreases. .

  In addition, “hue” that differs depending on each color is indicated by a * and b * values, a * indicates a red (+) to green (−) direction, and b * indicates a yellow (+) to blue (−) direction, In each direction, the color becomes brighter as the absolute value increases, and the color becomes dull as it approaches 0. This makes it possible to digitize one color using L *, a *, and b *. In addition to “lightness” and “hue”, there is “saturation (C)” as a method for digitizing the degree of vividness, which can be obtained by the following calculation formula.

  Similarly, C shows that the color becomes brighter as the absolute value increases, and the color becomes dull as the value decreases.

  All color reproduction areas that can be represented by a single printed matter (including color spaces other than printed matter) are called color rendering regions (gamut). The simplest way to represent gamut is as follows: a * is the horizontal axis, b * vertical axis In the two-dimensional space, the solid color part (yellow, red, indigo) and the solid color overprinting part (yellow x red, red x indigo, indigo x yellow) total of 6 colors a * vs b *, It can be expressed by the plotted hexagonal area. The larger the gamut area, the wider the color reproduction area.

  Regarding the yellow ink used in the present invention, the L * value when overprinted in the density range of 1.40 to 2.00 on the black ink printed within the range of L * value of 12.0 to 14.0. If it has transparency that does not exceed 17, there is little influence on the underprinting ink when the secondary and tertiary colors are overprinted, and a good color reproduction region can be obtained. Furthermore, it is also possible to use C.I. Pigment Yellow 83 as a complementary color by adding 0.5 to 10%, preferably 2 to 5% of the above yellow pigment.

  Examples of red pigments used in the present invention include, but are not limited to, rhodamine-based dyes such as rhodamine B, rhodamine 3G and rhodamine 6G, molybdenum and tungsten metal lake compounds. Moreover, it is also possible to use C.I. Pigment Red 48: 1 as a complementary color by adding 0.01 to 0.10%, preferably 0.01 to 0.05% of the above red pigment.

  The copper phthalocyanine compound, which is a cyan pigment used in the present invention, is a substance exhibiting a crystal polymorphism (homogeneous heterocrystal), and α, β, γ, ε, π, τ, ρ, χ depending on the crystal structure. However, it is preferable to use the β type, which is excellent in crystal stability and dispersibility.

  In the present invention, a copper halide phthalocyanine compound in which a hydrogen atom on a benzene ring of a phthalocyanine molecule is substituted with a halogen compound is added to the copper phthalocyanine compound in an amount of 5 to 15%, more preferably 8 to 11%. It is possible to expand the color reproduction region of green and purple when overprinting with yellow and red ink without impairing the color reproduction region of indigo ink single color.

  Examples of the black pigment include carbon black such as C.I. Pigment Black 7.

  Examples of the green pigment include halogenated phthalocyanine compounds. The most commonly used is chlorinated copper phthalocyanine, and there are others that are brominated instead of chlorine, those that contain chlorine and bromine, and those that do not contain copper. Specifically, C.I. I. Pigment green 7 or C.I. I. It is preferable that the pigment green 36 is contained in an amount of 15 to 30%, preferably 16 to 25%, based on the total weight of the ink. Furthermore, these pigments may be used alone or in combination of two or more.

  Examples of the synthetic resin used in the present invention include polyvinyl chloride, poly (meth) acrylic acid ester, epoxy resin, polyester resin, polyurethane resin, cellulose derivatives (for example, ethyl cellulose, cellulose acetate, nitrocellulose), vinyl chloride-acetic acid. Examples include vinyl copolymers, polyamide resins, polyvinyl acetal resins, diallyl phthalate resins, alkyd resins, rosin-modified alkyd resins, petroleum resins, urea resins, and synthetic rubbers such as butadiene-acrylonitrile copolymers. These resins can be used alone or in combination of two or more thereof. In either case, a resin that is soluble in a monomer having an ethylenically unsaturated double bond is used.

In the present invention, the monomer refers to monofunctional or polyfunctional (meth) acrylates, and the viscosity of the ink composition can be adjusted by appropriately using these monomers. The oligomer used in the present invention is an alkyd acrylate. Epoxy acrylate, urethane-modified acrylate, etc. are used. One or more photopolymerization initiators can be appropriately added to the active energy ray-curable ink as a component that accelerates the curing action.

  As photopolymerization initiators, benzophenone, 4-methylbenzophenone, 4,4-diethylaminobenzophenone, diethylthioxanthone, 2-methyl-1- (4-methylthio) phenyl-2-morpholinopropan-1-one, 4-benzoyl -4′-methyldiphenyl sulfide, 1-chloro-4-propoxythioxanthone, isopropylthioxanthone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxy-cyclohexyl-phenyl ketone, bis-2, 6-dimethoxybenzoyl-2,4,4-trimethylpentylphosphine oxide, 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one, 2, 2-dimethyl-2-hydroxyacetate Enone, 2,2-dimethoxy-2-phenylacetophenone, 2,4,6-trimethylbenzyl-diphenylphosphine oxide, 2-benzyl-2-dimethylamino-1- (morpholinophenyl) -butan-1-one, etc. Is mentioned. A photo accelerator such as p-dimethylaminobenzoic acid ethyl ester or pentyl 4-dimethylaminobenzoate may be used in combination with the photopolymerization initiator.

  As auxiliary agents, for example, anti-friction agents, anti-blocking agents, slipping agents, anti-scratch agents, carnauba wax, wax, lanolin, montan wax, paraffin wax, microcrystalline wax and other natural waxes, Fischer-Trops wax Synthetic waxes such as polyethylene wax, polypropylene wax, polytetrafluoroethylene wax and polyamide wax, silicone additives, leveling agents, constitutions and the like can be used as appropriate.

  The active energy ray-curable ink in the present invention can be printed by a known printing method such as offset printing, letterpress printing, screen printing, and flexographic printing in the same manner as ordinary printing ink.

  Examples of the active energy ray used in the present invention include ultraviolet rays and electron beams. However, it need not be limited to this.

EXAMPLES Next, although an Example demonstrates this invention further in detail, the scope of the present invention is not limited to these description Example. In addition, the part of the following description represents a weight part and% represents weight%.
(Example of varnish production)
Example of Varnish Production 30 parts of Dap Tote DT170 (manufactured by Tohto Kasei Co., Ltd.) is added to 70 parts of DPHA (manufactured by Nippon Kayaku Co., Ltd.) heated to 90 ° C to 100 ° C and heated and dissolved at 90 ° C to 100 ° C for 1 hour. And got the varnish.
(Example of yellow ink)
As a pigment, C.I. I. Pigment Yellow 176 (manufactured by Permanent Yellow GRX86 Clariant) was kneaded using three rolls with a dispersion particle measuring machine (grind meter) at a blending ratio shown in Table 1 until it became 7.5 microns or less, and yellow ink 1 was obtained.

As a pigment, C.I. I. Pigment Yellow 13 (Zay-452, manufactured by Dainichi Seika Kogyo Co., Ltd.) was used and kneaded using three rolls at a blending ratio shown in Table 1 until it became 7.5 microns or less with a dispersed particle system measuring machine (grind meter). Meat was obtained and yellow ink 2 was obtained.
(Red ink example)
As a pigment, C.I. I. Pigment red 81 / C.I. I. Pigment White 21 (Fernal Rose Toner 170 manufactured by Arimoto Chemical Co., Ltd.), C.I. I. Pigment red 81 / C.I. I. Basic Red 12 (Pink MP-617 manufactured by Arimoto Chemical Co., Ltd.), C.I. I. Pigment Red 48: 1 (LIONOL RED 2BFG3300 manufactured by Toyo Ink Mfg. Co., Ltd.) was used, and three rolls were used until the mixture ratio shown in Table 1 was 7.5 microns or less with a dispersed particle system measuring machine (grind meter). Kneaded to obtain red ink 1.
(Example of indigo ink)
As a pigment, C.I. I. Pigment Blue 15: 3 (LIONOL BLUE FG7351 manufactured by Toyo Ink Co., Ltd.), C.I. I. Using Pigment Green 7 (LIONOL GREEN YS-2A manufactured by Toyo Ink Manufacturing Co., Ltd.), using three rolls until the blending ratio shown in Table 1 is 7.5 microns or less with a dispersed particle measuring machine (grind meter). The indigo ink 1 was obtained by kneading.
(Example of green ink)
As a pigment, C.I. I. Using Pigment Green 7 (LIONOL GREEN YS-2A manufactured by Toyo Ink Manufacturing Co., Ltd.), using three rolls until the blending ratio shown in Table 1 is 7.5 microns or less with a dispersed particle measuring machine (grind meter). The green ink 1 was obtained by kneading.
(Comparative example)
Here, FD Carton ACE colors, which are the most common UV curable inks, were used as comparative inks.

The transparency of yellow ink was evaluated by the following test method.
Yellow ink was overprinted at a density of 1.50 to 2.00 on black ink printed within an L * value of 6.0 to 8.0, and L * was measured. The results are shown in Table 3.

  The yellow ink of the example does not exceed 12.0 even if the density value is increased to 2.00, and it is difficult to affect the black ink of the underprint, and it can be said that L * is excellent in transparency. The smaller the value, the more black it is, and the larger the value, the whiter it is).

On the other hand, L * is high in the comparative example, and it can be seen that the black ink of the underprinted ink is hindered because the yellow ink of the overprinted is opaque.
(Print evaluation test)
About the ink of the said Example and a comparative example, under the following printing conditions, each solid density value of yellow, red, indigo, and green is yellow: 1.40-1.44, red: 1.52-1.56, Indigo: Printed within a range of 1.63-1.67, green: 1.90-1.94 (as indigo density), and the printed matter was evaluated. The black ink was a high-concentration type ultraviolet curable printing ink, and was printed within a density value range of 1.45 to 2.15.

Printing conditions Printing machine: Heidelberg Speedmaster Kikuzen 4-color machine (Heidelberg Japan Ltd.)
Paper: Tokishi Art Double Sided 110Kg (Mitsubishi Paper Co., Ltd.)
Dampening solution: Astro Mark 3 (Niken Chemical Research Co., Ltd.) 2.0% tap aqueous solution Printing speed: 10,000 sheets / hour Concentration: Monochromatic print (yellow, red, indigo, black, green) with Gretag Macbeth D196 ) Measure the density value of the solid part.

  The printed matter evaluation results are shown in FIG. 1 and FIG. In addition, Table 2 shows L * a * b * measurement values of the single-color solid portion and the overprint portion.

From these results, ISO standard Japan color standard paper, for example, “Special Rhibo Art Double Sided 46/110 kg” manufactured by Mitsubishi Paper Industries Co., Ltd., yellow, red, indigo and green density values, with yellow being 1.40. To 1.44, red is 1.52-1.56, indigo is 1.63-1.67, green: 1.90 to 1.94 (as indigo density). The color rendering area (gamut) of the printed matter obtained using this ink includes a color rendering area (gamut) obtained using general ISO standard Japan color compliant ink and general UV curable ink. Thus, it can be seen that since it has a wider area, it has a wider color reproduction region.

  The obtained spectral reflectance curve is shown in FIG. Compared to the conventional ink of the comparative example, the ink of the example is closer to the ideal spectral reflectance curve, and unnecessary absorption of the portion that must be completely reflected is reduced. Therefore, the turbidity component of the ink is reduced and the C value representing the color saturation is high (Table 2).

Therefore, according to the present invention, the color gamut of Japan color is included, and it is possible to reproduce a color reproduction region that could not be reproduced by the conventional ultraviolet curable ink, and a wider color rendering region can be expressed. An active energy ray-curable ink can be provided.

"It is the figure which showed the printed matter evaluation result (Example 1, comparative example)." "It is the figure which showed the printed matter evaluation result (Example 2, comparative example)." “It is a diagram showing the ideal spectral reflection curve (yellow, red, indigo).” “A diagram showing spectral reflection curves (yellow, red, indigo) obtained in Examples and Comparative Examples.”

Claims (6)

  Four colors of yellow, red, indigo, and green are used for printing active energy ray-curable inks using any two, three, or four of yellow ink, red ink, indigo ink, and green ink, and black ink. Is a yellow ink containing a disazo yellow compound as a pigment component, a red ink containing a rhodamine dye metal lake compound as a pigment component, an indigo ink containing a phthalocyanine compound as a pigment component, and a halogenated phthalocyanine compound as a pigment component. An active energy ray-curable ink composition comprising a combination with a green ink.   As a disazo yellow compound, CI pigment yellow 12 or CI pigment yellow 13 is contained in an amount of 5 to 20% and printed on black ink having an L * value of 6.0 to 8.0 in a density range of 1.40 to 2.00. 2. The yellow ink according to claim 1, wherein the yellow ink has transparency so that the L * value does not exceed 12.0.   2. The red ink according to claim 1, comprising 15 to 30% of C.I. Pigment Red 81 or C.I Pigment Violet 1 as a metal lake compound of a rhodamine dye.   The indigo ink according to claim 1, comprising 10 to 25% of C.I. Pigment Blue 15: 3 or C.I. Pigment Blue 15: 4 and 0.5 to 2.0% of C.I. Pigment Green 7 as a phthalocyanine compound.   2. The green ink according to claim 1, comprising 10 to 30% of C.I. Pigment Green 7 or C.I. Pigment Green 36 as the halogenated phthalocyanine compound. (A) Yellow, (b) Red, (c) In the reflection spectrum of the spectral reflection curve of the 100% solid color portion of each indigo,
(A) Yellow has a relative reflection intensity of 0 to 10% in the wavelength region of 400 nm to 480 nm and 80 to 100 in the wavelength region of 550 nm to 700 nm when the total reflection is 100% in the wavelength region of 400 nm to 700 nm. % Reflection spectrum,
(B) When the total reflection is 100% in the wavelength region of 400 nm to 700 nm, the maximum reflectivity in the wavelength region of 400 nm to 500 nm is 35% to 100%, and in the wavelength region of 500 nm to 560 nm. A reflectance of 0 to 10%, a reflectance of 630 nm to 700 nm, a reflectance spectrum of 70% to 100%,
(C) Indigo has a maximum reflectance of 50 to 100% in the wavelength region of 400 nm to 530 nm and a reflectance of 0 to 10 in the wavelength region of 400 nm to 530 nm when the total reflection is 100% in the wavelength region of 400 nm to 700 nm. The printing method according to claim 1, wherein each ink having a% reflection spectrum is used.