JPS591317B2 - UV curing printing ink - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ultraviolet curable printing ink that is rapidly cured and dried by irradiation with ultraviolet rays. A polyisocyanate compound having two or more isocyanate groups: acid group: isocyanate group = 1:
Reaction product obtained by reacting at a molar ratio of 1.6 to 3 [
Acid group: Epoxy group ■1:
A UV-polymerizable unsaturated compound obtained by reacting the reaction product [■] at a molar ratio of 0.8 to 1.2 (provided that at least one of the organic acid residues in the compound is unsaturated) It is a monobasic acid residue.

) [■] at least 20% by weight (provided that it is obtained by reacting the reaction product of a vegetable oil fatty acid and a diisocyanate compound with the reaction product of acrylic acid or methacrylic acid or a mixture thereof and an epoxy resin) (excluding varnishes containing at least 50% by weight of UV-polymerizable unsaturated compounds). Traditionally, printing in lithographic offset printing, letterpress printing, etc. involves drying through the penetration of drying oils, semi-drying oils, high-boiling solvents, resins, etc., and dry printing through oxidative polymerization by adding oxidative polymerization catalysts and absorbing oxygen in the air. Since printing ink using an ink vehicle is used, it takes a long time to dry, from several minutes to several hours, especially when the printing substrate has a non-absorbent surface such as an aluminum foil metal plate or a plastic film. For products, it takes an extremely long drying time of several hours to more than 10 hours because there is no set drying due to penetration, which causes "backing".
In order to prevent drying and drying, it is necessary to apply large amounts of spray powder, perform ``slatting'', and further ``ventilate'' to accelerate drying.

In addition, in heat set type off-wheel printing and metal plate printing,
A heat drying oven requires a lot of space, equipment costs, and energy. Furthermore, most of the heat-set types cause many problems such as air pollution and environmental hygiene because they diffuse solvents into the atmosphere. The present invention has been made in order to improve the various drawbacks that occur when using such conventionally known printing inks, and it does not require the use of large amounts of organic solvents, and it does not require the use of a heat drying oven, which requires high equipment costs and costs. The object of the present invention is to provide an ultraviolet curable printing ink that can be dried extremely easily and quickly by ultraviolet irradiation without the use of ultraviolet rays.

Among various compositions that can be cured by ultraviolet irradiation, those whose main components are esters of unsaturated monobasic acids such as acrylic esters or methacrylic esters have a fast curing speed. The reaction product of an unsaturated monobasic acid such as methacrylic acid and an epoxy resin has a fast curing speed even in air and has excellent storage stability. An ultraviolet curable printing ink containing a mixture of monomers as a main component has also been proposed (Japanese Patent Laid-Open No. 49-21205).

However, although such printing inks have excellent drying properties, they generally have poor affinity with pigments, and are unable to maintain appropriate consistency such as viscosity, elasticity, and fluidity as inks.
Printed matter also has the disadvantage of lacking gloss, and it is difficult to dissolve in the hydrocarbon-based cleaning solvents traditionally used in printing operations, so ketone-based, aromatic-based, and ester-based solvents have to be used. However, these solvents also have the disadvantage that conventional printing equipment cannot be used as is because they damage the rubber rollers, blankets, and even the printed areas of the offset plate.

Furthermore, the reaction product of the unsaturated monobasic acid and epoxy resin has a free hydroxyl group in its molecule, so it is highly emulsified by water, and in printing that uses water, such as offset printing, there is a problem of "water loss". '', and other failures such as ``poor transfer'' and ``staining'' occurred, making it unsuitable as a vehicle for printing ink. Another object of the present invention is to improve the drawbacks of such conventionally known ultraviolet curable printing inks and to provide them with sufficient properties as printing inks. For this purpose, the present inventors first developed an ultraviolet polymerization method obtained by reacting a reaction product of a vegetable oil fatty acid and a diisocyanate compound with a reaction product of acrylic acid or methacrylic acid or a mixture thereof and an epoxy resin. Developed an ultraviolet curable printing ink whose main component is a varnish containing at least 50% by weight of sexually unsaturated compounds, and applied for a patent (1973).
4-22124 and Japanese Patent Application No. 10033/1984), but as a result of further studies, the present invention was completed. That is, the present invention combines an unsaturated monobasic acid, a higher fatty acid having 8 or more carbon atoms, or a mixture thereof and a polyisocyanate compound having two or more isocyanate groups in the molecule in a ratio of acid group to isocyanate group in a ratio of 1:1. .6~
A reaction product [1] obtained by reacting at a molar ratio of 3,
An unsaturated monobasic acid, a higher fatty acid having 8 or more carbon atoms, or a mixture thereof and an epoxy compound having two or more epoxy groups in the molecule, acid group: epoxy group -1:0.8~
A UV-polymerizable unsaturated compound obtained by reacting the reaction product [ ] with a molar ratio of 1.2 (provided that at least one of the organic acid residues in the compound is an unsaturated monobasic acid residue) It is.

) [] containing at least 20% by weight (However, ultraviolet rays obtained by reacting a reaction product of a vegetable oil fatty acid and a diisocyanate compound with a reaction product of acrylic acid or methacrylic acid or a mixture thereof and an epoxy resin) (excluding varnishes containing at least 50% by weight of polymerizable unsaturated compounds) is an ultraviolet curable printing ink whose main component is UV curable printing ink. The ultraviolet polymerizable unsaturated compound [] in the present invention does not necessarily have to be a single compound, and may be a mixture of various reaction products, and in the present invention, these [1] and [] All reaction products obtained by the reaction are collectively called ultraviolet polymerizable unsaturated compounds. In such ultraviolet ray polymerizable unsaturated compounds, a compound represented by the following general formula usually exists as a main reaction product.

[In the formula, R is an unsaturated monobasic acid residue, a higher fatty acid residue having 8 or more carbon atoms, or a mixture thereof; It is never a fatty acid residue.

k is a hydrogen atom or a methyl group. Z is a hydrogen atom or 1CONH-Y-(-NHCOR)l, 1-1
Although it is an integer of ~4, all Z contained in one molecule are not hydrogen atoms. Here, Y represents a polyisocyanate compound skeleton. m represents an integer of 2 to 12, and X represents an epoxy compound skeleton. ] Here, as the epoxy compound skeleton X, the above-mentioned ones are exemplified. In addition, examples of the polyisocyanate compound skeleton Y include those having layers.

In the present invention, the reaction product [1] is reacted with the free hydroxyl group of the reaction product [] and the reaction product [1] is reacted with the reaction product [1].
] By bonding the isocyanate groups with urethane, free hydroxyl groups are reduced and water resistance in printing is improved. It is effective to introduce higher fatty acid residues into a part of the molecule.

The reaction product obtained in this way has a UV-polymerizable unsaturated group in its molecule, so it cures quickly when exposed to UV rays, and also has excellent dispersibility with pigments, extender pigments, etc. In addition to the characteristics such as a large amount of organic solvent being mixed in, there is no need for forced thermal drying, so there is no problem with solvent volatilization, and ordinary hydrocarbon solvents can be used for cleaning after treatment as usual. It has excellent characteristics such as The configuration of the present invention will be explained in detail below.

Examples of the reaction product [1] used in the present invention include hydrofuric acid, nonanoic acid, lauric acid, palmitic acid,
stearic acid, oleic acid, linoleic acid, linolenic acid,
Eleostearic acid, and higher fatty acids with 8 or more carbon atoms such as fatty acids obtained from animal and vegetable oils and fats such as linseed oil, tung oil, dehydrated castor oil, soybean oil, safflower oil, perilla oil, beef tallow, etc., or acrylic acid, Unsaturated monobasic acids such as methacrylic acid and crotonic acid or mixtures thereof and tolylene diisocyanate, xylylene diisocyanate, lysine diisocyanate, hexamethylene diisocyanate, diphenylmethane diisocyanate, dimer acid diisocyanate A polyisocyanate having two or more isocyanate groups in the molecule, such as, is preferably used in a ratio such that the molar ratio of acid groups to isocyanate groups is 1:1.6 to 3.
A tertiary amine compound such as triethylamine as a catalyst under mild conditions of 70°C or less at a ratio of 2 to 2.4,
Using an organic metal compound or metal salt, etc., if necessary, an appropriate organic solvent such as acetone, ethers, benzene, toluene, tetrahydrofuran, trimethylolpropane triacrylate or methacrylate, tri- or tetraacrylate of pentaerythritol, or methacrylate, diethylene glycol diacrylate or methacrylate, oil fatty acid modified trimethylolpropane acrylate or methacrylate,
Examples include those reacted in the presence of polymerizable monomers such as styrene and divinylbenzene. Examples of reaction products [] include epichlorohydrin or methyl epichlorohydrin and bisphenol A1 resorcinol, aniline, oxybenzoic acid, m-hydrosacyaniline, o-cresol novolak, glycols, polyhydric alcohols, and halogenated phenols. One or more di- or triglycidyl-type epoxy compounds synthesized by reaction with the above-mentioned unsaturated monobasic acids or higher fatty acids having 8 or more carbon atoms, or mixtures thereof, are combined into an epoxy group and an acid. The molar ratio of the groups is preferably 1:0.8 to 1.2, preferably 1:
Hydroquinone, 2-methylhydroquinone, hydroquinone monomethyl ether, and catalysts such as triethylamine, triethanolamine, hexamethylphosphoramide, p-toluenesulfonic acid, and tetramethylammonium chloride at a temperature of 80°C to 150°C at a ratio of 1 to 1. Examples include those obtained by adding and reacting a thermal polymerization inhibitor such as p-benzoquinone. And the ultraviolet polymerizable unsaturated compound referred to in the present invention is the reaction product [1] obtained in this way.
It is easily synthesized by reacting and [] at a temperature usually below 70° C. in the presence of the above-mentioned appropriate organic solvent or polymerizable monomer, if necessary. At this time, reaction products [1] and [] must be selected so that at least one of them contains an unsaturated monobasic acid residue. Further, the reaction ratio between the reaction products [1] and [] can be freely changed depending on the purpose and use of the UV-polymerizable unsaturated compound to be produced. In this case, although it is not necessarily necessary to react all of the remaining hydroxyl groups of the reaction product [], it is generally not preferable to leave free isocyanate groups of the reaction product [1]. This is because the isocyanate group easily reacts with moisture in the air, water during printing, etc., resulting in gelation and coagulation. The ultraviolet curable varnish used in the ultraviolet curable printing ink of the present invention may contain the ultraviolet ray polymerizable unsaturated compound obtained in this manner alone or, if necessary, trimethylolpropane triacrylate or methacrylate as a viscosity modifier. , pentaerythritol tri- or tetraacrylate or methacrylate, diethylene glycol diacrylate or methacrylate, neopentyl glycol diacrylate or methacrylate, anolyl fatty acid-modified trimethylolpropane diacrylate or methacrylate, styrene, -divinylbenzene, etc. body, and the reaction product []
It is made by adding UV-polymerizable resins such as unsaturated epoxy ester resins and unsaturated epoxy ester resins. Furthermore, if necessary, conventionally used vegetable oils and their polymerized oils, rosin-modified phenolic resins, rosin-modified ester resins, various modified alkyd resins, p-tolutensulfonic acid amide formalin resins,
It is made by adding and using various petroleum resins, etc. At this time, it is necessary that the UV-curable varnish contains 20% by weight or more of the UV-polymerizable unsaturated compound and the content of non-polymerizable resins is limited to 30% by weight or less. The ultraviolet curable printing ink referred to in the present invention includes organic pigments, inorganic pigments, extender pigments and
It is obtained by adding dyes and mixing and kneading.

It is desirable that the temperature at this time does not exceed 60°C. In addition,
At this time, as ultraviolet polymerization initiators, benzoin polymerization initiators such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzophenone polymerization initiators such as benzophenone, Michler's ketone, β-naphthalenesulfonyl chloride, p-chlorobenzene, etc. Halogenated sulfonyl polymerization initiators such as sulfonyl, quinone polymerization initiators, ketone polymerization initiators,
and a mixture thereof in an amount of 1 to 15 weight percent in the ink. In addition, if the varnish contains drying oil, semi-drying oil, or these fatty acids, use a type of kendryer made of metal stones such as lead, manganese, cobalt, nickel, and cerium, which are conventionally used as oxidative polymerization catalysts. Each component can be added depending on the amount. Further, when the printing material has an absorbent surface such as paper, there is no problem in using conventionally used high-boiling hydrocarbon solvents in the ink at a concentration of up to 5% by weight for viscosity adjustment. Further, by adding waxes, plasticizers, curing accelerators, etc., it is possible to make ultraviolet curable printing inks according to the intended use. The present invention will be explained in detail below using synthesis examples and examples. Synthesis example 1 Sumieboxy ELA- in a 500TILe4 flask
128 (manufactured by Sumitomo Chemical, epoxy resin obtained by the reaction of bisphenol A and epichlorohydrin, epoxy equivalent: 184 to 194), 0.65 mol of 2-methylhydroquinone, and 1.3 mol of acrylic acid were sequentially charged. , stir thoroughly.

Furthermore, 1.77 g of triethylamine is added, and the temperature is raised to 110° C. while being careful not to generate heat. Stirring was continued at this temperature for about 4 hours, and when the acid value reached 7 or less, the reaction was terminated and the temperature reached about 6
0°C and quenched again, 2-methylhydroquinone 0.066
y, trimethylolpropane triacrylate 1337
was added and diluted. A slightly yellow, transparent liquid with a viscosity of Z6 to Z7 (Cardner viscometer: 25°C) was obtained. This is called compound (a). Next, in a 500 m 14 flask equipped with a cooling tube, a thermometer, and a dropping load, trimethylolpropane triacrylate 1937 and p-benzoquinone 0.
19y, and stir.

Furthermore, tolylene diisocyanate (80% 2.4 isomer)
, 2.6 isomer (20%) and 0.437 mole of triethylamine were added and heated with stirring to give a solution of about 30%
Bring to 45°C in minutes. 0.5 Lunatsuku O-A (manufactured by Kao Soap Co., Ltd., oleic acid) was mixed in advance while maintaining this temperature.
0.867 mol of triethylamine is added dropwise over a period of about 2 hours. Thereafter, the temperature was kept at 50°C and stirring was continued for about 1 to 2 hours, and the reaction was terminated when the free isocyanate groups reached 6%, and the mixture was immediately cooled to 25°C. Internal temperature is 25
When the temperature reaches 0.degree. C., 225 fi of the contents remain, and 0.2 f of the above compound (a) 200y1p-benzoquinone is added, and the mixture is sufficiently stirred and mixed. Thereafter, the temperature was gradually raised to 50° C., and the reaction was carried out at the same temperature for about 30 minutes. Dibutyltin diacetate was added as a catalyst in an amount of 0.15% based on the total amount, and the same amount was further added after 30 minutes. Continue at this temperature for about 2 to 3
Stirring was continued for a period of time, and the reaction was terminated when free isocyanate became 0.3% or less. A light brown transparent liquid with a viscosity of Z7 was obtained. This is referred to as an ultraviolet polymerizable unsaturated compound (A). Synthesis Example 2 The same operation as in Synthesis Example 1 was carried out except that 2-methylhydroquinone was replaced with p-benzoquinone, and trimethylolpropane triacrylate was taken out as it was without addition and dilution.

A pale yellow transparent highly viscous liquid was obtained. This is a compound (b)
shall be. Synthesis Example 1280.3 mol of Sumiepoxy ELA and Denacol EX-810 (
(Ethylene glycol type epoxy resin manufactured by Nagase Sangyo Co., Ltd.)
0.7 mol, 2-methylhydroquinone 0.21t1 acrylic acid 2 mol, tetramethylammonium chloride 2.1
f was charged, the reaction was carried out in the same manner as in Synthesis Example 1 (a), and the reaction was terminated when the acid value became 13 or less.
Rapidly cool to 0°C and add 0.09y of 2-methylhydroquinone.
, trimethylolfuropane triacrylate 181f was added and diluted.

A pale brown, transparent liquid with a viscosity of W-X was obtained. This is referred to as compound (c). Next, the same procedure as in Synthesis Example 1 was performed except that 137f of trimethylolpropane triacrylate, 0.14f of p-benzoquinone, 0.31y of triethylamine were used, and Lunatsuk was used instead of Lunatsuk O-A (oleic acid manufactured by Kao Soap Co., Ltd.). 8-95 (Kikifurylic acid manufactured by Kao Soap Co., Ltd.) 0.5 mol, triethylamine 0.6
The same operation was carried out except that 27 was used, and when the free isocyanate group reached 9%, the reaction was set as the end point, and immediately 25
Cool to ℃.

When the internal temperature has cooled to 25°C, the contents 2507 remain, and the above compound [250f] and p-benzoquinone 0
．． Inject 25 tons. Thereafter, the same operations as in Synthesis Example 1 were performed to obtain a light brown transparent liquid with a viscosity of Z6 to Z7. This is referred to as UV-polymerizable unsaturated compound B).

Synthesis Example 4 The same reaction was carried out except that 0.5 mol of n-nonanoic acid was used in place of Lunac 8-95 in Synthesis Example 3 to obtain a pale brown transparent liquid with a viscosity of Z6 to Z7.

This is referred to as an ultraviolet polymerizable unsaturated compound (q). Synthesis example 5
Sumiepoxy ELA-1280 in 114 Tulo flask.
Synthesis Example 1 The same procedure as in the synthesis of compound (a) was carried out, and the reaction was terminated when the acid value became 7 or less, cooled to about 60°C, and 2-methylhydroquinone 0.1y1 trimethylolpropane triacrylate 206y was added and diluted.

A light brown transparent liquid with a viscosity of Z5 to Z6 was obtained. This is referred to as compound (d). Next, perform the same procedure as in Synthesis Example 1 except that trimethylolpropane triacrylate 1637, p-benzoquinone 0.167, and triethylamine 0.36f1 are used, and in place of Lunatsuk O-A (oleic acid manufactured by Kao Soap Co., Ltd.). Anneal oil fatty acid 0.5 mol,
The same operation is carried out except that 0.727% of triethylamine is used, and the reaction is terminated when the free isocyanate group reaches 7%, and the reaction is immediately cooled to 25°C.

When the internal temperature has cooled to 25°C, 250 t of the contents remain and 250 y of the above compound (d) is added. Charge 0.257 g of p-benzoquinone. Thereafter, the same operations as in Synthesis Example 1 were performed to obtain a light brown transparent liquid with a viscosity of Z6 to Z7.
This is referred to as an ultraviolet polymerizable unsaturated compound O.

Synthesis Example 6 Trimethylolpropane triacrylate 170y, . p-benzoquinone 0.27
, 0.5 mol of tolylene diisocyanate and 0.357 mol of triethylamine were used.
The same operation was carried out except that 0.2 mole of acrylic acid and 0.77 mole of triethyl were used.
Cool to ℃. When the internal temperature reaches 25℃, the contents are 270℃.
Remaining y, add the compound 2507 and 0.25y of p-benzoquinone. Thereafter, the same operations as in Synthesis Example 1 were performed to obtain a light brown transparent liquid with a viscosity of Z6 to Z7.

This is referred to as UV-polymerizable unsaturated compound D. Synthesis example 7
0.84 mol of acetone 365f1 hexamethylene diisocyanate is charged into a 1e4 flask equipped with a cooling tube, a thermometer, and a dropping load, and heated with stirring to reach 45° C. in about 30 minutes.

Pre-mixed flaxseed oil fatty acid 0.8 while maintaining temperature
2y of triethylamine is added dropwise over a period of about 2 hours. Thereafter, stirring is continued for about 1 to 2 hours at the same temperature, and when the free isocyanate reaches 5.5%, the reaction is terminated, and the mixture is immediately cooled to 25°C. When the internal temperature reaches 25°C, leave 340t of the contents and add the compound (mouth) 2.
007 and 0.27 p-benzoquinone were added and stirred and mixed thoroughly. After that, perform the same operation as in Synthesis Example 1,
The reaction was terminated when the free isocyanate content became 0.3% or less, and trimethylolpropane triacrylate 2477 and p-benzoquinone 0.2y were added and diluted. Next, the volatile content contained in this compound was removed under reduced pressure until it became 3% or less. A light brown transparent liquid with a viscosity of Z6 to Z7 was obtained. This is referred to as UV-polymerizable unsaturated compound D.

Synthesis example 8 5 with cooling pipe, thermometer, and drip load installed
Acetone 277f1 Tolylene diisocyanate 0.42 mol, Triethylamine 0.
Prepare 46f and heat while stirring to reach 45℃ in about 30 minutes.
Make it.

While maintaining this temperature, pre-mixed Lunatsk O-A (
0.4 mol of oleic acid (manufactured by Kao Soap Co., Ltd.) and 0.69 t of triethylamine were added dropwise over a period of about 2 hours. After that, the same reaction as in Synthesis Example 1 was carried out, and the free isocyanate group was
The reaction was terminated when the temperature reached %, and the reaction was immediately cooled to 25°C. When the internal temperature reaches 25°C, leave 215 tons of the contents and add 100 tons of the above-mentioned compound pastry. Add 0.1 t of P-benzoquinone and stir and mix thoroughly. After that, the same operation as in Synthesis Example 1 was performed, and the free isocyanate was reduced to 0.
The reaction was terminated when the concentration reached 3% or less, and 0.03y of trimethylolpropane triacrylate (54f12-methylhydroquinone) was added to dilute it. Next, the volatile content contained in this compound was removed under reduced pressure until it became 3% or less. A pale yellow transparent liquid with a viscosity of Z7 was obtained. This is referred to as UV-polymerizable unsaturated compound Q.

Varnish synthesis example 1 UV polymerizable unsaturated compound A2OO7
A UV-curable varnish (H) having a viscosity of Z6 to Z7 is obtained by mixing 150f of compound varnish obtained in Synthesis Example 1.

Varnish synthesis example 2 UV polymerizable unsaturated compound 0300y
and the compound 50y obtained in Synthesis Example 2 to obtain an ultraviolet curable varnish (1) having a viscosity of Z7'.

Varnish Synthesis Example 3 A UV-curable varnish (J) having a viscosity of Z7 is obtained by mixing the UV-polymerizable unsaturated compound D25O7 and 100 t of the compound (B) obtained in Synthesis Example 2.

Varnish synthesis example 4 Ultraviolet polymerizable unsaturated compound Q2OO7 and compound (a) 150'It obtained in synthesis example 1 were mixed to give a viscosity of Z6 to Z.
, to obtain an ultraviolet curable varnish (K).

Varnish compound 5 UV polymerizable unsaturated compound 51707
and p-toluenesulfonic acid amide formalin resin 80f
and trimethylolpropane triacrylate 1007 to obtain an ultraviolet curable odor having a viscosity of Z7.

Varnish Synthesis Example 6 A UV-curable varnish with a viscosity of Z6+ is prepared by mixing the UV-polymerizable unsaturated compound P24Of and the compound obtained in Synthesis Example 2) 40f1 trimethylolpropane triacrylate 40y1 bentaerythritol tri- or tetraacrylate 40t. get.

Example 1 UV-polymerizable unsaturated compound (A) obtained in Synthesis Example 1 and UV-curable varnish (11, (1), ( .J),
Pigments are added to (5), (D, and (to), respectively, and thoroughly mixed and kneaded using three rolls at 60°C or lower, and a mixture of Michler's ketone, benzophenone, or benzoin methyl ether is added as an ultraviolet polymerization initiator. were further mixed to create ultraviolet curable printing inks Taki 1 to Taki 7.

The names and blending ratios of the compounds are as shown in Table-1. Furthermore, using each ink, printing was performed using a PS plate under normal printing conditions using an offset sheet-fed one-color machine (model name: Pearl, manufactured by Color Metal Co., Ltd.), and a linked ultraviolet irradiation device (oak The printing suitability and ultraviolet curing performance were compared using two ozone-less type high-pressure mercury lamps manufactured by the company.

Claims (1)

[Claims] 1. An unsaturated basic acid, a higher fatty acid having 8 or more carbon atoms, or a mixture thereof and a polyisocyanate compound having two or more isocyanate groups in the molecule as acid group: isocyanate group= A reaction product [I] obtained by reacting at a molar ratio of 1:1.6 to 3, an unsaturated basic acid or a higher fatty acid having 8 or more carbon atoms, or a mixture thereof, and two or more epoxy groups in the molecule. An ultraviolet polymerizable unsaturated compound obtained by reacting a reaction product [II] with an epoxy compound having At least one of the organic acid residues in the compound is an unsaturated basic acid residue.) A varnish containing at least 20% by weight of [III] (however, a reaction product of a vegetable oil fatty acid and a diisocyanate compound and an acrylic Excluding varnishes containing at least 50% by weight of ultraviolet polymerizable unsaturated compounds obtained by reacting acid, methacrylic acid, or a mixture thereof with a reaction product of an epoxy resin. UV-curable printing ink.