CN115948077A

CN115948077A - Ink composition

Info

Publication number: CN115948077A
Application number: CN202310078731.7A
Authority: CN
Inventors: 吴高峰; 龙芬; 吴伟才
Original assignee: Huizhou Foryou Optical Technology Co ltd
Current assignee: Huizhou Foryou Optical Technology Co ltd
Priority date: 2023-01-16
Filing date: 2023-01-16
Publication date: 2023-04-11
Anticipated expiration: 2043-01-16
Also published as: CN115948077B

Abstract

The present application provides an ink composition. The ink composition comprises an optically variable pigment and a connecting material, wherein the connecting material comprises photosensitive resin, an acrylic monomer and a photoinitiator, the surface of the optically variable pigment is subjected to oleophilic treatment by a treating agent, and the treating agent is set to ensure that the oil absorption of the optically variable pigment is 25g/100 g-75 g/100g. The surface of the optically variable pigment is treated, so that the formed ink composition has better transfer rate and high printing stability in offset printing, and the obtained printed pattern has obvious effect of color variation along with the angle.

Description

Ink composition

Technical Field

The application relates to the technical field of anti-counterfeiting, in particular to an ink composition.

Background

The ink with color-dependent performance is generally called photochromic ink, and the product printed by the photochromic ink (i.e. photochromic ink) generally has photochromic characteristic, i.e. shows different colors along with the change of the visual angle of human eyes when the user looks at the front or the side under sunlight. The light-variable characteristic has large color difference change and obvious characteristic, and can be identified without any instrument and equipment, so that light-variable ink is used for anti-counterfeiting of currency and valuable papers in many countries in the world.

The common printing technology of the optically variable ink is generally screen printing, compared with the screen printing technology, the UV offset printing is high in efficiency and environment-friendly, and the optically variable pigment is easy to transfer badly in the offset printing process due to the characteristics of the UV offset printing process and the platy characteristics of the optically variable pigment, so that the problem of uneven printing exists in the actual printing.

Disclosure of Invention

The application provides an ink composition to solve the problem that in the prior art, an optically variable pigment is easy to transfer badly in an offset printing process of optically variable ink, so that uneven printing exists in actual printing.

In order to solve the technical problem, the application adopts a technical scheme that: an ink composition is provided, which comprises an optically variable pigment and a binder, wherein the binder comprises a photosensitive resin, an acrylic monomer and a photoinitiator, wherein the surface of the optically variable pigment is subjected to oleophilic treatment by a treatment agent, and the treatment agent is set to make the oil absorption of the optically variable pigment to be 25g/100 g-75 g/100g.

Further, the treating agent is coated on the outer surface of the optically variable pigment, and the treating agent comprises at least one reactive group and at least one non-reactive group, wherein the reactive group comprises at least one of a silicon methoxy group, a silicon ethoxy bond, a hydroxyl group and a carboxyl group, and the non-reactive group comprises at least one of a pure alkyl group and a fluoro alkyl group.

Further, the treating agent includes at least one of an alkylsilane and a fluorosilane.

Further, the mass ratio of the binder to the optically variable pigment in the ink composition is less than 6.

Further, the particle diameter D of the optically variable pigment ₅₀ Is 0 to 30 microns.

Further, the photosensitive resin includes: the ink comprises rosin modified resin, polyester acrylic resin and a binder, wherein the binder further comprises a polymerization inhibitor, a filler and a dispersant, and the ink composition comprises the following components in percentage by weight: the mass percent of the optically variable pigment is as follows: 15-30% of rosin modified resin, by mass: 15-20% of polyester acrylic resin, by mass: 30-40% and the mass percentage of the acrylic monomer is as follows: 5-15% of photoinitiator by mass percent: 5-10% of polymerization inhibitor, and the mass percentage of the polymerization inhibitor is as follows: 0.1-1% and the filler comprises the following components in percentage by mass: 2-6% of dispersant, by mass: 1 to 5 percent.

Further, the rosin modified resin is a rosin modified polyester resin, and the functional group of the polyester acrylic resin is greater than or equal to 3.

Further, the acrylic monomer includes at least one of tripropylene glycol diacrylate, trimethylolpropane triacrylate, 1,6-hexanediol diacrylate, and propoxylated glycerol triacrylate.

Further, the photoinitiator comprises: 2,4,6 (trimethylbenzoyl) diphenylphosphine oxide, 3-methyl-4-phenylbenzophenone, 2-phenylbenzyl-2-dimethylamine-1- (4-morpholinebenzyl) butanone.

Further, the polymerization inhibitor comprises at least one of tris (N-nitroso-N-phenylhydroxylamine) aluminum salt, 4-hydroxy-2,2,6,6-tetramethylpiperidinyloxy radical and p-hydroxyanisole.

Further, the optically variable pigment includes at least one of an optically variable pigment, a pearlescent pigment and a liquid crystal pigment.

Further, the printing method of the ink composition is UV offset printing.

The beneficial effects of the embodiment of the application are that: in contrast to the prior art, the present application provides an ink composition comprising an optically variable pigment and a vehicle, wherein the surface of the optically variable pigment is subjected to an oleophilic treatment with a treating agent, the treating agent being set so that the oil absorption of the optically variable pigment is 25g/100g to 75g/100g. According to the UV offset printing ink composition, the optically variable pigment treated by the specific treating agent is combined with a proper ink formula, the obtained ink composition meets the requirement of offset printing, the ink composition has better transfer rate and high printing stability in UV offset printing, the obtained printed pattern has an obvious effect of changing color along with the angle, and the ink composition does not contain volatile organic solvents and is beneficial to environmental protection.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

FIG. 1 is a schematic representation of the content of optically variable pigments under a microscope for test specimen No. 1-4 in Table 2;

FIG. 2 is a schematic illustration of hue change formed from the data of Table 3;

FIG. 3 is a schematic diagram of the positive effect of one embodiment of the ink composition provided herein to produce a printed product;

FIG. 4 is a schematic side view of an embodiment of a printed matter obtained from the ink composition provided herein.

Detailed Description

The present application will now be described in detail with reference to specific embodiments thereof as illustrated in the accompanying drawings. These embodiments are not intended to limit the present application, and structural, methodological, or functional changes made by those skilled in the art according to these embodiments are included in the scope of the present application.

In addition, if there is a description of "first", "second", etc. in the embodiments of the present application, the description of "first", "second", etc. is for descriptive purposes only and is not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In addition, technical solutions between various embodiments may be combined with each other, but must be realized by a person skilled in the art, and when the technical solutions are contradictory or cannot be realized, such a combination should not be considered to exist, and is not within the protection scope of the present application.

The present application provides an ink composition in which the surface of an optically variable pigment that changes color with angle is treated to reduce the oil absorption of the optically variable pigment and promote the wettability and dispersibility of the optically variable pigment in the ink composition, thereby improving the transferability in offset printing applications; combining the surface treated optically variable pigment with a specific ink formula to prepare the ink composition meeting the offset printing requirement. The ink composition can be widely applied to package printing of cigarette packets, wine packets, cosmetics and the like. The ink composition will be described in detail below.

The ink composition comprises a binder and an optically variable pigment, wherein the binder comprises a photosensitive resin, an acrylic monomer and a photoinitiator.

In the ink composition of the present application, the optically variable pigment may be an optically variable pigment, and the optically variable pigment may be subjected to oleophilic treatment to reduce the interfacial tension of the optically variable pigment, specifically, the surface of the optically variable pigment is subjected to oleophilic treatment with a treating agent provided so that the oil absorbency of the optically variable pigment is 25g/100g to 75g/100g.

The optical variable pigment generally comprises a metal material and an inorganic oxide material, both of which have larger surface energy, and in addition, as known from the preparation process of the optical variable pigment thin film, a great amount of gaps or defects exist inside the optical variable pigment thin film during physical vapor deposition, so that the specific surface area of the pigment is large, and meanwhile, the optical variable pigment thin film also generates a great amount of sections in subsequent crushing processing. The above effects result in a large oil absorption of the optically variable pigment, which leads to poor dispersion and compatibility of the optically variable pigment in the ink, and is not favorable for use of the optically variable pigment in offset inks.

In the application, after the optically variable pigment is subjected to surface treatment by a proper treatment agent, the surface tension of the optically variable pigment can be reduced, macroscopically, the oil absorption of the optically variable pigment is reduced, and the oil absorption is reduced, so that the finally formed ink composition has lower viscosity, which is beneficial to subsequent printing transfer. In addition, the surface layer of the surface-treated optically variable pigment is an organic compound substance with certain polarity, and the connecting material or the monomer used in the ink composition is also an organic substance with certain polarity, so that the surface-treated optically variable pigment has better compatibility in the ink according to the principle of similarity and compatibility among materials, thereby being more beneficial to the stability and dispersion of the optically variable pigment. Therefore, the optically variable pigment treated by the specific treating agent is combined with a proper ink formula to prepare the UV (Ultraviolet ray) offset printing optically variable ink meeting the offset printing requirement.

Based on the principle, the realization of the optically variable pigment can be divided into two parts, namely the surface treatment of the optically variable pigment with the color change along with the angle and the ink formula technology. The surface treatment of the photochromic pigment and the ink formulation technique will be described separately below.

Known from the production mode of the optically variable pigment, the optically variable pigment film deposited by normal physical vapor deposition has larger grain diameter, cannot be suitable for ink printing, and needs to be broken to be applied in small grain diameter; in the commonly used optically variable pigments, the particle diameter D of the optically variable pigment is combined with the characteristics of offset printing application ₅₀ From 0 to 30 microns, preferably from 2 to 15 microns, most preferably from 3 to 6 microns. D ₅₀ The grain diameter corresponding to the cumulative volume percentage of the optically variable pigment reaching 50 percent, namely the volume distribution median grain diameter, wherein D ₅₀ The test is obtained by a laser particle size analyzer test method.

Optionally, the method for surface modification of optically variable pigments comprises: liquid phase coating methods and solid mixture methods. Preferably, the surface of the optically variable pigment may be modified by a liquid phase coating method to reduce the surface tension of the optically variable pigment.

The reduction of the oil absorption of the optically variable pigment can be achieved by reducing the specific surface area of the optically variable pigment or the surface tension of the optically variable pigment, but the present application is directed to the reduction of the specific surface tension of the optically variable pigment having a particle size, since the specific surface area of the optically variable pigment is substantially constant. The optically variable pigment with the optically variable color generally comprises a metal substance, an inorganic oxide substance or an inorganic substance, and the materials have higher polarity and higher surface tension, so that the surface of the optically variable pigment can be coated with a layer of organic matter to reduce the surface tension of the optically variable pigment and reduce the oil absorption of the optically variable pigment.

The oil absorption of the optically variable pigment with the color variation along with the angle after surface treatment is in the following range, and the optically variable pigment can be used for a subsequent offset printing optically variable ink system: the treating agent may be provided so that the oil absorption of the optically variable pigment is 25g/100g to 75g/100g. The larger the oil absorption of the optically variable pigment is, the higher the viscosity of the ink composition is, and the poorer the transferability is, and through practical verification, the oil absorption of the optically variable pigment is found to be 25g/100 g-75 g/100g, preferably 30g/100 g-50 g/100g, so that the formed offset ink has better transferability in application. Test methods for oil absorption reference is made to GB/T5211.15-2014 pigment and extender pigment general test methods part 15: method for measuring oil absorption.

Optionally, the treating agent is coated on the outer surface of the optically variable pigment, and the treating agent may comprise at least one reactive group and at least one non-reactive group, wherein the reactive group comprises at least one of a silicon methoxy group, a silicon ethoxy bond, a hydroxyl group and a carboxyl group, and the non-reactive group comprises at least one of a pure alkyl group and a fluoro alkyl group.

The treating agent includes at least one of an alkylsilane and a fluorine-containing silane. For example, satisfactory treatments may include: hexadecyl trimethoxy silane, dodecyl trimethoxy silane, cyclohexyl trimethoxy silane, perfluoro decyl triethoxy silane, dodecafluoro heptyl propyl methyl dimethoxy silane, perfluoro octyl triethoxy silane, perfluoro octyl trimethoxy silane, etc.

The general amount of the treating agent is 0-10% (relative to the amount of the optically variable pigment), preferably 0.1-6%, and most preferably 0.2-2%; if the dosage of the treating agent is too low, the surface of the optically variable pigment is not covered sufficiently, the surface tension cannot be effectively reduced, and the oil absorption cannot be effectively reduced; if the amount of the treating agent is too high, the treated optically variable pigment is agglomerated, which affects the dispersibility of the optically variable pigment in the ink composition, and the treatment cost is increased if the amount of the treating agent is too high.

In the ink composition, the mass ratio of the connecting material to the optically variable pigment is less than 6. The binder is other substances except the optically variable pigment in the ink composition, and for example, the binder includes a photosensitive resin, an acrylic monomer, a photoinitiator and the like. Optionally, the binder may further include a polymerization inhibitor, a filler, a dispersant, and the like.

Further, the photosensitive resin includes: rosin modified resins and polyester acrylic resins. The content of each component in the ink composition may be: the mass percent of the optically variable pigment is as follows: 15-30% of rosin modified resin, by mass: 15-20% of polyester acrylic resin, by mass: 30-40% and the mass percentage of the acrylic monomer is as follows: 5-15% of photoinitiator by mass percent: 5-10% of polymerization inhibitor, by mass: 0.1-1%, the mass percentage of the filler is as follows: 2-6% of dispersant, by mass: 1 to 5 percent.

The rosin modified resin can be rosin modified polyester resin, and the functional group of the polyester acrylic resin is greater than or equal to 3.

Further, the photoinitiator comprises: 2,4,6 (trimethylbenzoyl) diphenylphosphine oxide, 3-methyl-4-phenylbenzophenone, 2-phenylbenzyl-2-dimethylamine-1- (4-morpholinebenzylphenyl) butanone.

Further, the dispersant may be selected from BYK168 or lubotun brand wetting dispersant 24000, used alone or as a mixture of the two.

Further, the optically variable pigment includes at least one of an optically variable pigment, a pearlescent pigment (such as a pearlescent dragon), and a liquid crystal pigment.

The printing mode of the ink composition is UV offset printing. The ink layer is formed by printing the ink composition on the substrate, and the curing mode is UV curing.

In the ink composition, the wall material of the optically variable pigment can be subjected to oleophilic treatment to reduce the interfacial tension of the wall material, so that the UV binder can be spread on the wall material of the optically variable pigment unit to wet the optically variable pigment; in addition, by utilizing reasonable resin collocation and an ink process, the wetted optically variable pigment is uniformly dispersed in a resin system to form a stable spatial structure, thereby solving the technical problems of dispersion and wetting of the optically variable pigment in the shape of a color-variable flake along with the angle change. The ink composition provided by the application can be well transferred and transferred on a UV offset printing machine; the printing ink has good printing adaptability and stability, can be well transferred to a printing substrate to form a benign ink layer, and the printed ink layer has the effect of changing color along with the angle.

Therefore, the ink technology is combined with oleophylic treatment of the optically variable pigment surface with the angle-dependent color variation, the prepared UV offset printing angle-dependent color variation ink composition is good in transfer rate and high in UV curing speed in offset printing, and a printed image layer has an obvious angle-dependent color variation effect.

The preparation of the optically variable pigments and ink compositions of the present application will be exemplified by experiments below.

Example 1 pigment treatment

The preparation method comprises the following steps of (1) crushing WG (silver gray positive color, green side color) optically variable pigment film generated by physical vapor deposition to form optically variable pigment with optically variable color with particle size D50 of (8-10) microns, simultaneously naming the optically variable pigment sample with optically variable color as sample No. 1, dispersing the optically variable pigment with optically variable color No. 1 in a solvent to form a pigment mixture with solid content of 15%, heating to 60 ℃, adding 1.5% of perfluorodecyl triethoxysilane (relative to the amount of the optically variable pigment with optically variable color, the same below) serving as a treating agent, reacting for 6 hours, then carrying out solid-liquid separation, cleaning with the previous reaction solvent to remove the excess treating agent, and drying at 105 ℃ to obtain optically variable pigment sample No. 2 with optically variable color after surface treatment.

The oil absorption records of samples 1# and 2# tested by the method for measuring the oil absorption of GB/T5211.15-2014 are shown in the following table 1.

Example 2 pigment treatment

The preparation method comprises the following steps of (1) crushing a GR (positive color: green, side color: purplish red) optically variable pigment film generated by physical vapor deposition to form an optically variable pigment with the optically variable color with the particle size D50 of (5-6) microns, simultaneously naming a sample of the optically variable pigment with the optically variable color as a sample No. 3, dispersing the optically variable pigment with the optically variable color No. 3 in a solvent to form a pigment mixture with the solid content of 20%, heating to 75 ℃, adding a treating agent hexadecyl trimethoxy silane 3%, reacting for 2 hours, then carrying out solid-liquid separation, cleaning with the former reaction solvent to remove the redundant treating agent, and then drying at 105 ℃ to obtain a sample of the optically variable pigment with the optically variable color No. 4 after surface treatment.

The oil absorption records of samples 3# and 4# tested by the method for measuring the oil absorption of GB/T5211.15-2014 are shown in the following table 1.

The formula technology of the ink composition is as follows:

example 3

2 samples (sample # 1 and sample # 2) obtained in example one were added to base stock formulation 1 for test validation.

This example provides a UV curable offset printing goniochromatic ink composition, which has the following formulation (mass fraction): 20% of oleophylic optically variable pigment with angle-dependent color variation, 15% of UV rosin modified resin, 50% of UV polyester acrylic resin (EB 811), 4.4% of UV acrylic monomer, 7% of photoinitiator, 0.5% of filler (calcium carbonate), 1% of wax powder (polyethylene wax), 2% of dispersant (Lu Borun 24000) and 0.1% of polymerization inhibitor.

The preparation method comprises the following steps:

according to the total amount of the formula, 15% of UV rosin modified resin, 50% of UV polyester acrylic resin (EB 811), 4.4% of UV acrylic monomer (EM 2380), 7% of photoinitiator and 0.1% of polymerization inhibitor are sequentially added into a charging barrel of a high-speed dispersion machine, and are stirred for 30-60min at the rotating speed of 500-1000 r/min to obtain a mixture A.

According to the total amount of the formula, 20 percent of optically variable pigment with the color changing along with the angle, 0.5 percent of filler, 1 percent of wax powder and 2 percent of dispersant are sequentially added into the mixture A and uniformly stirred at a low speed by a high-speed dispersion machine, and then a grinding machine is used for grinding until the fineness reaches below 10 microns to prepare the UV curing offset printing optically variable ink composition.

It should be noted that: (1) When the optically variable pigment with the optically variable color of the flop added in the formula is sample No. 1 optically variable pigment obtained in example 1, the optically variable pigment is a sample No. 1 offset printing ink composition shown in Table 2; (2) When the optically variable pigment of optically variable color with flip-flop added to the formulation was sample 2# optically variable pigment obtained in example 1, it was sample number 2 offset ink composition in table 2.

Example 4

2 samples from example two (sample # 3 and sample # 4) were added to base stock formulation 2 for test validation.

This example provides a UV-curable offset printing ink with a flip-flop color, which has the following formulation (mass fraction): 20% of oleophylic-treated angle-dependent heterochromatic photochromic pigment, 13% of UV modified epoxy resin (B-151), 50% of UV polyester acrylic resin (Boxing B-536), 6% of UV acrylic monomer (EM 2380), 8% of photoinitiator, 1% of wax powder (polyethylene wax), 2% of dispersant (Lu Borun 24000) and 0.1% of inhibitor.

The preparation method comprises the following steps:

according to the total amount of the formula, 13% of UV modified epoxy resin, 50% of UV polyester acrylic resin (B-536), 6% of UV acrylic monomer (EM 2380), 8% of photoinitiator and 0.1% of polymerization inhibitor are sequentially added into a charging barrel of a high-speed dispersion machine, and are stirred for 30-60min at the rotating speed of 500-1000 r/min to obtain a mixture A.

According to the total amount of the formula, 20 percent of optically variable pigment with the color changing along with the angle, 1 percent of wax powder and 2 percent of dispersant are sequentially added into the mixture A and uniformly stirred at a low speed by a high-speed dispersion machine, and then a grinding machine is used for grinding until the fineness reaches below 10 micrometers to obtain the UV curing offset printing optically variable ink.

It should be noted that: (1) When the optically variable pigment with the optically variable color according to the angle is the sample No. 3 optically variable pigment obtained in example 2, the optically variable pigment is the sample No. 3 offset printing ink composition shown in Table 2; (2) When the optically variable pigment with optically variable color of the flop added to the formulation was sample No. 4 optically variable pigment obtained in example 2, it was sample No. 4 offset ink composition in Table 2.

Ink printability detection method: the test was carried out using an IGT C1 printability tester and a Heidelberg 7-color printer.

The test results of the above examples are as follows:

TABLE 1 oil absorption test results for the effect pigment samples

Serial number	Pigment sample	Oil absorption (g/100 g)	Remarks to note
				1	1#	64.85
2	2#	32.90	1# surface treatment
				3	3#	75.82
4	4#	39.25	Obtained by surface treatment of No. 3

TABLE 2 summary of the test results of the different matching methods for the effect pigment samples

Note: the offset ink transfer test was performed using an IGT C1 printability tester.

The results in tables 1 and 2 show that the ink compositions obtained from samples 2# and 4# after surface treatment have better transferability and printability when printed under the same formula, and the effect of the color variation of the printed pattern is better, while the samples 1# and 3# of pigments without surface treatment are relatively poorer.

Offset ink transfer comparison: the sample numbers 1-4 in Table 2 are shown in FIG. 1 for the amount of pigment flakes in the microscope.

And (3) sample tension light variation effect characterization: an adaptive test specimen of sample # 2 + formulation 1, an adaptive test specimen of sample # 4 + formulation 2 and a sample # 4 + formulation 2 are tested at different angles by a multi-angle tester (model: BYK data color), the hue value (ab) is as shown in the following table 3, and a hue change table formed according to the data of the table 3 is as shown in the figure 2.

TABLE 3 color phase values of various samples at different angles measured by multi-angle tester

The results show that:

(1) Compared with the oil absorption of samples No. 1 and No. 2, no. 3 and No. 4 in Table 1, the oil absorption value of the optically variable pigment with flip-flop color after the surface treatment by the treatment agent is obviously smaller, which indicates that the optically variable pigment with flip-flop color after the surface treatment is successfully modified.

(2) The printed swatches of the flexographic ink composition obtained in example 3 showed under microscope observations as (a) and (b) in fig. 1, wherein (a) in fig. 1 is a schematic under microscope of the printed swatches of the ink composition obtained in sample # 1 + formulation 1 and (b) in fig. 1 is a schematic under microscope of the printed swatches of the ink composition obtained in sample # 2 + formulation 1, the number of optically variable pigments in (b) being significantly greater than (a), indicating that the offset UV ink transfer performance of the non-surface treated pigment sample # 1 is significantly worse than the offset UV ink of the surface treated pigment sample # 2 under the same ink formulation. The same applies to the offset ink composition obtained in example 4, and as shown in fig. 1 (c) and (d), fig. 1 (c) is a schematic view under a microscope of a print sheet of the ink composition obtained in sample # 3 + formulation 2, and fig. 1 (d) is a schematic view under a microscope of a print sheet of the ink composition obtained in sample # 4 + formulation 2.

(3) The hue values of the samples in different observation angles in Table 3 show that the offset UV ink composition prepared by the optically variable pigment 2# or 4# with the optically variable color with the angle variation after surface treatment shows better effect of the optically variable color with the angle variation no matter on the test samples or on a machine for printing.

The UV offset printing flip-flop ink composition provided by the application has a good printing effect in a Heidelberg 7-color printing machine test, the front effect of a printed matter is shown in figure 3, and the side effect of the printed matter is shown in figure 4.

In summary, the ink composition provided by the application has good transfer rate and high printing stability in the use of UV offset printing, the obtained printed pattern has an obvious effect of changing color along with the angle, and the printed product does not contain volatile organic solvents, thereby being beneficial to environmental protection.

It should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art will be able to make the description as a whole, and the embodiments may be appropriately combined to form other embodiments as will be appreciated by those skilled in the art.

The above-listed detailed description is only a specific description of possible embodiments of the present application and is not intended to limit the scope of the present application, and equivalent embodiments or modifications made without departing from the technical spirit of the present application should be included in the scope of the present application.

Claims

1. An ink composition comprising an optically variable pigment and a vehicle, the vehicle comprising a photosensitive resin, an acrylic monomer and a photoinitiator, wherein the surface of the optically variable pigment is oleophilic-treated with a treating agent, the treating agent being provided so that the optically variable pigment has an oil absorption of 25g/100g to 75g/100g.

2. The ink composition as claimed in claim 1, wherein the treating agent is coated on the outer surface of the optically variable pigment, the treating agent comprises at least one reactive group and at least one non-reactive group,

wherein the reactive group comprises at least one of a silicon methoxy group, a silicon ethoxy bond, a hydroxyl group and a carboxyl group,

the non-reactive group includes at least one of a pure alkyl group and a fluoro alkyl group.

3. The ink composition of claim 2, wherein the treating agent comprises at least one of an alkylsilane and a fluorosilane.

4. The ink composition as claimed in claim 1, wherein the mass ratio of the binder to the optically variable pigment in the ink composition is less than 6.

5. The ink composition as claimed in claim 1, wherein the optically variable pigment has a particle size D ₅₀ Is 0 to 30 microns.

6. The ink composition according to claim 1, wherein the photosensitive resin comprises: rosin modified resin and polyester acrylic resin, the connecting material also comprises a polymerization inhibitor, a filling material and a dispersing agent,

wherein, in the ink composition: the optically variable pigment comprises the following components in percentage by mass: 15-30% of rosin modified resin, wherein the mass percentage of the rosin modified resin is as follows: 15-20% of polyester acrylic resin, wherein the mass percentage of the polyester acrylic resin is as follows: 30-40% of acrylic monomer, wherein the acrylic monomer comprises the following components in percentage by mass: 5-15% of photoinitiator, wherein the mass percent of the photoinitiator is as follows: 5-10% of polymerization inhibitor, wherein the polymerization inhibitor comprises the following components in percentage by mass: 0.1-1% of the filler, wherein the mass percentage of the filler is as follows: 2-6% of dispersant, wherein the mass percentage of the dispersant is as follows: 1 to 5 percent.

7. The ink composition according to claim 6, wherein the rosin-modified resin is a rosin-modified polyester resin, and the functional group of the polyester acrylic resin is 3 or more.

8. The ink composition of claim 1, wherein the acrylic monomer comprises at least one of tripropylene glycol diacrylate, trimethylolpropane triacrylate, 1,6-hexanediol diacrylate, and propoxylated glycerol triacrylate.

9. The ink composition of claim 1, wherein the photoinitiator comprises: 2,4,6 (trimethylbenzoyl) diphenylphosphine oxide, 3-methyl-4-phenylbenzophenone, 2-phenylbenzyl-2-dimethylamine-1- (4-morpholinebenzyl) butanone.

10. The ink composition of claim 6, wherein the polymerization inhibitor comprises at least one of tris (N-nitroso-N-phenylhydroxylamine) aluminum salt, 4-hydroxy-2,2,6,6-tetramethylpiperidine nitroxide and p-hydroxyanisole.

11. The ink composition of claim 1, wherein the optically variable pigment comprises at least one of an optically variable pigment, a pearlescent pigment, and a liquid crystal pigment.

12. The ink composition of claim 1, wherein the ink composition is printed by UV offset printing.