KR101284016B1 - Composition of Color Shifting Ink for Intaglio Printing - Google Patents

Abstract

The present invention relates to a color conversion ink composition for intaglio printing used in the production of various securities or security prints, and more particularly, to a color conversion ink composition for intaglio printing containing a color conversion pigment made of chromium and having a solvent content. By further including an alkyd-based varnish in which the solid content, molecular weight and the like are appropriately adjusted, it is possible to improve the overall physical properties of the color conversion ink composition for intaglio printing, and to improve the high-speed printing ability of the intaglio printing color conversion ink composition with little ink scattering. It is about.
The color conversion ink composition for intaglio printing according to the present invention has no ink scattering when printing at a high speed, and thus the high speed printing ability is good, and the effects of improving various physical properties such as variety of color conversion effects, chemical resistance, alkali resistance, and wear resistance at the same time It is expected that commercial applications in the field of authenticity of anti-counterfeiting and security documents are expected.

Description

Composition of Color Shifting Ink for Intaglio Printing

The present invention relates to a color conversion ink composition for intaglio printing used in the production of various securities or security prints, and more particularly, to a color conversion ink composition for intaglio printing containing a color conversion pigment made of chromium and having a solvent content. By further including an alkyd-based varnish in which the solid content, molecular weight and the like are appropriately adjusted, it is possible to improve the overall physical properties of the color conversion ink composition for intaglio printing, and to improve the high-speed printing ability of the intaglio printing color conversion ink composition with little ink scattering. It is about.

Intaglio printing is a method in which a plate-shaped line portion is recessed more than a non-line portion, so that ink is deposited on the recessed portion, and in particular, the intaglio printing sufficiently inks. It is a special printing method used for security printing products such as banknotes, checks, securities, bonds, stamps and ID cards because it can be used and print patterns appear as thin lines.

This intaglio printing features thick metal plates that can thicken the ink and can be imitated in general by sculpting the metal plates, which are widely used to produce precision and anti-counterfeiting printed products. It can print at high speed of more than 6000 sheets per hour.

On the other hand, intaglio inks used in the above-described intaglio printing generally have various characteristics as follows.

Since the ink layer transferred to the paper by the intaglio printing method is very thick, about 20 to 200 μm, the viscosity of the ink is relatively high, and it requires unusual viscoelasticity such as unusual tack change according to the roll transition of the ink. The ink-blotting system which is not seen at is being introduced. In the intaglio printing, the concave portion of the intaglio (main part) is filled with ink, and the ink on the part except the recess is wiped off with a wiping roller or doctor, and the ink on the wiping roller or doctor should be wiped off. At this time, it is necessary to wash the ink on the wiping roller or doctor with an alkaline aqueous solution. Therefore, the intaglio ink should have a property of being easily dispersed and washed in an alkaline wiping solution, unlike ordinary ink, and after drying and curing, it should no longer have such properties.

Since the intaglio printing is printed while rotating at a high speed, the intaglio ink is not to be scattered, and the ink must be made to transfer ink well on paper. In addition, the thickly transferred ink layer should be dried quickly so that there is no backing, so that the drying or setting of the ink should be good, and the curing of the ink should not occur during long-term storage or on a printing press, and is prepared by the intaglio ink printing. Printed materials generally require chemicals in circulation, chemical resistance to solvents, solvent resistance, and wear resistance that the ink layer does not easily fall off or break.

In addition, the intaglio printing can provide a depth of about 20 to 200 µm and a width of up to 2 mm in the metal sheet, so that special pigments having a relatively large particle size (0.5 to 100 µm), for example, pearl pigments, copper powder, and silver Powders, encapsulated pigments, metal deposition powders, acicular pigments, flaky pigments and the like by using the ink there is an advantage that can exhibit the effect of the pigment in the printed product. However, these special pigments are large and have a specific particle model, so it is very difficult to produce intaglio inks with good printability.

Looking at the related art related to the present invention, Korean Patent No. 0935381 discloses an ink composition and a printed material prepared by screen and gravure ink after passivation in order to reduce the corrosion of the pigment showing the color conversion function, and registered in Korea Patent No. 0633751 discloses an ink composition that complements color conversion effect and durability improvement by using a first pigment manufactured by a physical metal deposition method and a second pigment manufactured by a wet and chemical method, and registered in Korea. Patent 0649609 discloses intaglio ink compositions comprising pearl pigments, physical metal deposition pigments and chemically coated pigments that exhibit photovariable properties.

However, the ink composition of Korean Patent No. 0935381 has a disadvantage in that the entire surface of the reflective layer and the dielectric layer or the chemically exposed surface must be coated with a passivating agent, and the ink composition of Korean Patent No. 0633751 is intended to improve the durability of the pigment. There is a problem in that at least two kinds of expensive pigments have to be used, and the ink composition of Korean Patent No. 0649609 has a problem in that it is a pearl type pigment manufactured by a chemical wet method, which has a strong durability and low color conversion effect.

Therefore, the present inventors have made diligent efforts to solve the above problems, and as a result, the varnish contained in the color conversion ink composition for intaglio printing has a lower solvent content, a higher solid content, and further contains an alkyd-based varnish having a high molecular weight. When the reflective layer contains a color conversion pigment made of chromium, it was confirmed that the physical properties of the color conversion ink composition for intaglio printing were improved, the ink dispersion was small and the high speed printing aptitude was good, thus completing the present invention.

The main object of the present invention is to provide a color conversion ink composition for intaglio printing, which has good high-speed printing aptitude and can simultaneously improve and improve various physical properties such as variety of color conversion effects, chemical resistance, alkali resistance and wear resistance.

In order to achieve the above object, the present invention is a color conversion pigment; Urethane modified alkyd varnishes; First alkyd varnish; Second alkyd varnish; filler; additive; And a solvent, wherein the color conversion pigment is composed of a partial reflection layer, a dielectric layer, and a multilayer thin film of the reflection layer, and the reflection layer provides a color conversion ink composition for intaglio printing, wherein the reflection layer is chromium (Cr).

The color conversion ink composition for intaglio printing according to the present invention has no ink scattering when printing at a high speed, and thus has high speed printing aptitude, and can simultaneously improve various properties such as variety of color conversion effects, chemical resistance, alkali resistance, and wear resistance. Effective and expected commercial applications in the field of authenticity of anti-counterfeiting and security documents.

1 schematically shows a color conversion pigment structure of a color conversion ink composition for intaglio printing according to the present invention.
Figure 2 shows the color conversion effect of the color conversion ink composition for intaglio printing according to the present invention, (a) is a color seen from the front, (b) is a color seen from the side.
3 is an image measuring the durability of the color conversion ink composition for intaglio printing according to the present invention, (a) is the case of using the ink of Comparative Example 1, (b) is a color conversion ink composition for intaglio printing of the present invention If it is.
Figure 4 is an image measuring the color conversion effect of the color conversion ink composition for intaglio printing according to the present invention, (a) is a case using the color conversion ink composition for intaglio printing of the present invention, (b) is the ink of Comparative Example 3 This is the case.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In describing the present invention, detailed descriptions of related well-known functions or configurations are omitted in order not to obscure the subject matter of the present invention.

As used herein, the term 'color shifting effect' means that colors appear differently depending on an angle viewed by a material. In addition, although it is expressed as a two-color effect, an optically variable effect, etc., in the present invention, collectively referred to as a 'color shifting effect', a pigment having such a color conversion effect It is referred to as 'color conversion pigment'.

The present invention is a color conversion pigment; Urethane modified alkyd varnishes; First alkyd varnish; Second alkyd varnish; filler; additive; And a solvent, wherein the color conversion pigment comprises a partial reflection layer, a dielectric layer, and a multilayer thin film of the reflection layer, and the reflection layer relates to a color conversion ink composition for intaglio printing, wherein the reflection layer is chromium (Cr).

At this time, the intaglio printing color conversion ink composition 10 to 25% by weight of the color conversion pigment; 15-25 wt% of a urethane-modified alkyd varnish; 10-20% by weight of the first alkyd varnish; 5-10 wt% second alkyd varnish; Filler 7-17 wt%; Additive 1 to 19% by weight; And 5 to 8% by weight solvent.

When printing color conversion ink, the plate-shaped color conversion pigment should be evenly distributed in a certain direction so that the light incident on the ink layer can be reflected at the same angle to show an excellent color conversion effect. When added in less than 10% by weight of the composition, there is a problem that the color conversion pigment distribution density is too small to have a weak color conversion effect, when it exceeds 25% by weight, the pigment density in the ink is high, rather a constant dispersion of the pigment Since it becomes difficult, the color becomes dark or the angle of the reflected light is not constant, so there is a problem that the color change becomes unclear. In addition, when the urethane-modified alkyd varnish is mixed at less than 15% by weight, the durability of the ink is weak and the fluidity of the ink is deteriorated, and when it exceeds 25% by weight, printability problems such as scattering may occur. .

In addition, when the first alkyd varnish is added in less than 10% by weight to the color conversion ink composition for intaglio printing, there is a problem that the fluidity of the ink is lowered and ignorance (water dispersion) is not good, and when it exceeds 20% by weight, it is scattered. There is a printability problem, such as, the second alkyd varnish has a role of preventing the scattering, so if it is added less than 5% by weight has an adverse effect on the printability, there is a problem that the viscosity of the ink is higher than 10% by weight. On the other hand, when the filler is added less than 7% by weight, the viscosity of the ink may be lowered and the transition of the ink may be worse.On the contrary, when the filler is more than 17% by weight, it is difficult to control the rheology of the ink and excessive initial transition may occur during printing. It becomes possible.

In addition, when the additive is added in less than 1% by weight to the color conversion ink composition for intaglio printing, there is a problem that the drying and uncleaning of the printed matter may be bad and the backing occurs, when the ink exceeds 19% by weight is transferred during printing In the process, there is a possibility of drying or poor durability, if the solvent is added less than 5% by weight, the viscosity and the ink of the ink is too high, there is a problem that the transition of the ink is excessive, if it exceeds 8% by weight of the ink There is a problem of metastasis worsening.

In the present invention, the color conversion pigment is prepared in a multilayer structure in which the partial reflective layer, the dielectric layer and the reflective layer are laminated on the substrate in the order of the partial reflective layer / dielectric layer / reflective layer / dielectric layer / partial reflective layer by vacuum deposition, electron beam or sputtering, The multilayer thin film layer is separated from the substrate, and is a metal-deposited color conversion pigment prepared by grinding by particle. The partially reflective layer contains chromium, the dielectric layer contains silicon dioxide and the reflective layer contains chromium.

Intaglio printing ink compositions having the above-described composition ratio are usually prepared by mixing, stirring and grinding in a method of preparing an intaglio printing ink composition.

Conventional color conversion pigments have a drawback that the color conversion effect is sharply lowered by chemical reaction with acid and / or alkali during ink production, and because the color is sensitively changed according to the angle change, the recognition of the color may be small. In the case of the color conversion pigment, the durability of the pigment itself is improved by using chromium (Cr), which is relatively resistant to acids and alkalis, in the reflective layer, thereby improving the durability of the ink.

In addition, the color of the color conversion pigment according to the present invention can be adjusted according to the thickness change of the partial reflection layer / dielectric layer / reflection layer / dielectric layer / partial reflection layer of the multi-layer structure, the total thickness of the color conversion pigment is preferably 1,300nm. At this time, the color mainly changes according to the thickness change of the dielectric layer, and typical colors include gold / green, green / purple, green / blue, purple / green, etc. (front / side color), and a specific pigment or dye Mixing can change the color change to some extent. The particle size of the color conversion pigment can be adjusted according to the intended use, and typically has a size of about 5 to 30 μm and a particle thickness of about 1 μm for a printing ink.

In the present invention, the urethane-modified alkyd varnish, the first alkyd varnish and the second alkyd varnish are used for the purpose of a colorant. The urethane-modified alkyd varnish and the first alkyd varnish are acid value 30 to 35 in consideration of dispersibility, printability, ink film aptitude, durability, chemical resistance, dryness, etc. It is most preferable that the viscosity is 300-400poise (25 degreeC), the weight average molecular weights 20,000-25,000, and the 1st alkyd varnish has an acid value of 65-70, the viscosity 400-700poise (25 degreeC), and the weight average molecular weights 8,000-12,000. Most preferred.

In particular, the second alkyd varnish reduces the fatty acid content from 40 to 45% by weight to 25 to 35% by weight in order to improve ink scattering and printing aptitude generated when using a metal-deposited color conversion pigment. Reaction was carried out in an amount increased from 12 to 18% by weight to 15 to 25% by weight, and from 25 to 30% by weight to 32 to 42% by weight, and then aliphatic hydrocarbon solvent or glycol ether solvent to 5 to 10% by weight. By adding it, the solvent content is low, the solid content is high, and a high molecular weight alkyd varnish is prepared and used. At this time, the acid value of the second alkyd varnish is 45 to 60, the viscosity is 1,000 to 1,800 poise (25 ℃), the weight average molecular weight of 30,000 to 45,000 is most preferred. Thus, the second alkyd varnish can impart transferability suitable for high speed intaglio printing and can significantly reduce ink scattering.

In the present invention, the filler is silica, to control the rheological properties of the ink (viscosity, tack, etc.) and to control the transition of the ink during printing, preferably a fumed silica group consisting of a particle size of 10 ~ 30nm Is selected. Typical products include R-972 and R-812 by Evonik Degussa (Germany).

In the present invention, the additive includes at least one selected from the group consisting of wax, mixed desiccant and dispersant. The wax is added to improve the anti-backing effect, and carnauba wax, polytetrafluoroethylene (PTFE) wax, and mixed waxes thereof are used. In addition, the mixed desiccant is to improve the chemical durability of the printed matter by improving the internal drying of the ink, and a mixed desiccant containing a salt of Ca, Mn and Zr in an aliphatic petroleum solvent is used.

At this time, the additive may be added to adjust the physical properties of the ink to maintain the properties such as printability, dryness, durability, weather stability, abrasion, etc. to suit the intaglio printing, preferably the color conversion ink composition for intaglio printing At least one is selected from the group consisting of 2-7 wt% wax, 1-5 wt% mixed desiccant and 3-7 wt% dispersant, based on the total weight.

In the present invention, the solvent is for controlling the physical properties of the ink composition, using a glycol solvent, an aliphatic hydrocarbon type and a mixed solvent thereof, preferably a mixture of a glycol solvent and an aliphatic hydrocarbon solvent is used. . The glycol solvent may be used by mixing one or more selected from the group consisting of diethylene glycol monobutyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether, aliphatic hydrocarbon solvents gaseous stability and non-paper In order to improve aptitude, it is preferable to mix and use the solvent of the boiling point 190-210 degreeC, and / or the solvent of the boiling range 230-320 degreeC.

The color conversion ink composition for intaglio printing according to the present invention includes a high molecular weight second alkyd varnish to prevent ink scattering during high speed printing, improve printability, and at the same time contain chromium in the reflective layer of the color conversion pigment. Various physical properties such as variety of effects, chemical resistance, alkali resistance and wear resistance can be improved.

Hereinafter, the present invention will be described in more detail with reference to Examples. These examples are only for illustrating the present invention, and it will be apparent to those skilled in the art that the scope of the present invention is not interpreted to be limited by these examples.

[ Example  One]

To prepare a raw material to have a composition ratio of Table 1. At this time, the average particle size of the color conversion pigment was used 20㎛, the solvent used a high boiling point aliphatic hydrocarbon-based mixed solvent having a boiling point of 250 ℃.

division Composition ratio (wt%) Color conversion pigments 17 Urethane Modified Alkyd Varnish (weight average molecular weight 23,000) 23 First alkyd varnish (weight average molecular weight 10,000) 17 2nd alkyd varnish (weight average molecular weight 35,000) 8 Filler (R-972) 14 Wax (carnauba wax) 5 Mixed desiccant (cobalt, zirconium, calcium) 3 Dispersant (sodium dodecylbenzenesulfonate) 4 Solvent (butyl carbitol, aliphatic hydrocarbon) 9 Sum 100

[ Comparative example  One]

To prepare an ink composition in the same manner as in Example 1 after preparing the raw material to have a composition ratio of Table 2.

division Composition ratio (wt%) Color conversion pigments 17 Urethane Modified Alkyd Varnish (weight average molecular weight 23,000) 17 First alkyd varnish (weight average molecular weight 10,000) 23 2nd alkyd varnish (weight average molecular weight 35,000) 8 Filler (R-972) 14 Wax (carnauba wax) 5 Mixed desiccant (cobalt, zirconium, calcium) 3 Dispersant (sodium dodecylbenzenesulfonate) 4 Solvent (butyl carbitol, aliphatic hydrocarbon) 9 Sum 100

[ Comparative example  2]

To prepare a raw material to have a composition ratio of the following Table 3, an ink composition was prepared in the same manner as in Example 1.

division Composition ratio (wt%) Color conversion pigments 17 Urethane Modified Alkyd Varnish (weight average molecular weight 23,000) 26 First alkyd varnish (weight average molecular weight 10,000) 20 2nd alkyd varnish (weight average molecular weight 35,000) 2 Filler (R-972) 14 Wax (carnauba wax) 5 Mixed desiccant (cobalt, zirconium, calcium) 3 Dispersant (sodium dodecylbenzenesulfonate) 4 Solvent (butyl carbitol, aliphatic hydrocarbon) 9 Sum 100

[ Comparative example  3]

To prepare a raw material to have a composition ratio of Table 4 below to prepare an ink composition in the same manner as in Example 1.

division Composition ratio (wt%) Color conversion pigments 35 Urethane Modified Alkyd Varnish (weight average molecular weight 23,000) 17 First alkyd varnish (weight average molecular weight 10,000) 12 2nd alkyd varnish (weight average molecular weight 35,000) 5 Filler (R-972) 10 Wax (carnauba wax) 5 Mixed desiccant (cobalt, zirconium, calcium) 3 Dispersant (sodium dodecylbenzenesulfonate) 4 Solvent (butyl carbitol, aliphatic hydrocarbon) 9 Sum 100

[ Experimental Example  One]

The physical properties of the color conversion ink composition for intaglio printing prepared in the same composition as in the above embodiment are as follows. First, the test (Tack-O-Scope, test conditions: Laura temperature 40 ℃, Laura speed 50m / min, sample amount 1g ), The initial value / maximum value was 110-150 / 140-210, and the second drying time (at 25 ℃) ranged from 10-13 hours. Third, 0.8% caustic soda and 0.3% lot oil Good erosion was shown. Intaglio printing color conversion ink prepared from the intaglio printing color conversion ink composition prepared in Example 1 was printed at a speed of 8,000 sheets per hour by a high-speed intaglio printing machine (Super Orlof Intaglio, Switzerland, KBA GIORI Co., Ltd.). , Uncleanness, print sharpness, and paperless aptitude were good, and as shown in FIG. 2, the color conversion effect was also excellent.

In addition, the printed matter printed with the intaglio printing color conversion ink prepared in Example 1 and the printed matter printed with the ink prepared in Comparative Example 1 were immersed in 2% sodium hydroxide solution for 30 minutes to the alkaline solution of the printed matter. Durability was measured.

As a result, as shown in Figure 3, the printed matter printed with the color conversion ink for intaglio printing of Example 1 was found to maintain the color before the test was confirmed that the durability is excellent, while Comparative Example 1 was found to be inferior in durability.

On the other hand, Comparative Example 2, the ink of which the second alkyd varnish content was reduced in the ink formulation of Example 1, was found to have a lot of scattering during printing, resulting in poor printing aptitude, and Comparative Example 3 in which the color conversion pigment content was increased in Example 1 The color of the printed matter (FIG. 3B) printed with the ink of D was dark, and the color conversion effect was lower than that of the printed matter (FIG. 3A) printed with the ink of Example 1.

While the present invention has been particularly shown and described with reference to specific embodiments thereof, those skilled in the art will appreciate that such specific embodiments are merely preferred embodiments and that the scope of the present invention is not limited thereby. something to do. It is therefore intended that the scope of the invention be defined by the claims appended hereto and their equivalents.

Claims (7)

Color conversion pigments; Urethane modified alkyd varnishes; First alkyd varnish; Second alkyd varnish; filler; additive; And a solvent, wherein the color conversion pigment is composed of a multilayer thin film of a partial reflection layer, a dielectric layer, and a reflection layer, and is laminated in the order of a partial reflection layer / dielectric layer / reflection layer / dielectric layer / partial reflection layer, and the partial reflection layer and the reflection layer are chromium (Cr) and ,
The second alkyd varnish has an acid value of 45 to 60, a viscosity of 1,000 to 1,800 poise (25 ° C.), a weight average molecular weight of 30,000 to 45,000 physical properties of intaglio printing color conversion ink composition.
The color conversion ink composition of claim 1, wherein the color conversion ink composition comprises 10 to 25 wt% of a color conversion pigment; 15-25 wt% of a urethane-modified alkyd varnish; 10-20% by weight of the first alkyd varnish; 5-10 wt% second alkyd varnish; Filler 7-17 wt%; Additive 1 to 19% by weight; And Color conversion ink composition for intaglio printing, comprising a solvent 5 to 8% by weight.
The color conversion ink composition of claim 1, wherein the color conversion pigment is adjusted according to the thickness of the dielectric layer.
The color conversion ink composition for intaglio printing according to claim 1, wherein the urethane-modified alkyd varnish has an acid value of 30 to 35, a viscosity of 300 to 400 poise (25 ° C), and a weight average molecular weight of 20,000 to 25,000.
The color conversion ink composition of claim 1, wherein the first alkyd varnish has physical properties of an acid value of 65 to 70, a viscosity of 400 to 700 poise (25 ° C), and a weight average molecular weight of 8,000 to 12,000.
delete According to claim 1, wherein the additive is at least one in the group consisting of 2 to 7% by weight of wax, 1 to 5% by weight of mixed desiccant and 3 to 7% by weight of dispersant, based on the total weight of the color conversion ink composition for intaglio printing Color conversion ink composition for intaglio printing, characterized in that the selected.

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