LED-curable offset ink containing an aluminum additive

Abstract

One or more acrylates in which 25 to 85% of at least one acrylate is pentaacrylate or hexaacrylate; 0 to 20% of one or more photoinitiators; 5 to 60% of one or more rosin-modified polyester resins having a molecular weight of 5,000 to 35,000 daltons; 0.2 to 5% of one or more aluminum additives; 0.1 to 5% of one or more polymerization stabilizers; and 0 to 50% of a colorant. An LED-curable lithographic ink containing these components.

Description

Technical Field

[0001] The present invention relates to LED-curable printing inks or varnish compositions suitable for offset printing. In particular, the present invention relates to LED-curable varnishes and inks applied by offset printing that contain aluminum additives.

[0002] The inks and varnishes of the present invention can be cured with LED light and require less energy, making them more sustainable than traditional UV-curable inks and varnishes.

[0003] Furthermore, the present invention relates to printed matter that includes or is derived from the ink or varnish compositions according to the present invention, which are suitable for graphic and packaging applications.

Background Art

[0004] The curing of UV-LED light lamps is increasing in use because this technology offers various advantages such as energy savings; a longer lifespan than conventional UV bulbs; and a safe, mercury-free product. Furthermore, UV-LED bulbs do not generate ozone, in contrast to typical mercury UV bulbs that have been the state of the art in UV technology for many years.

[0005] Therefore, in the graphic arts sector, printing presses are increasingly being equipped or re-equipped with compact UV-LED dryers. Prior art LED dryers typically emit LED light with a peak wavelength of 365 - 405 nm.

[0006] For example, LED offset inks that can be printed on a sheet-fed or web-fed printing press equipped with an LED dryer are prior art. They combine the above-mentioned advantages of LED drying (i.e., LED curing) with a sustainable (A-free, i.e., solvent-free) application and rapid drying (high productivity) compared to solvent-based inks or inks based on vegetable or mineral oils.

[0007] However, like UV inks, UV-LED inks often exhibit insufficient lithographic printing performance when compared to conventional inks based on vegetable or mineral oils. One reason for this behavior is due to the high polarity of acrylates with respect to oils, which makes UV-LED inks more polar and can thereby have an adverse effect on the lithographic printing process and dampening water interactions.

[0008] Another drawback of UV-LED technology can also be poor surface curing caused by oxygen inhibition. Oxygen inhibition refers to the fact that oxygen as a radical can readily react with the radicals formed by photoinitiators or radicals on monomers or growing polymer chains and can render them inactive, usually as peroxide derivatives. This can result in insufficient drying on the ink or coating surface where oxygen is dominant. This is particularly a problem with commercially available long-wavelength UV-LED dryers that emit at 365 - 405 nm, as they lack the shorter wavelengths that are very useful for good surface curing and activation of photoinitiator radicals at or near the surface.

[0009] This is often counteracted by using highly reactive polyfunctional monomers such as dipentaerythritol hexaacrylate because the polymerization rate is more favorable than the oxygen inhibition process.

[0010] However, the extensive use of polyfunctional monomers (such as dipentaerythritol hexaacrylate) that impart a high crosslink density often imparts brittleness to the ink and can have an adverse effect on adhesion. Furthermore, such acrylate monomers can also cause poor printing performance.

[0011] To impart better lithographic properties to UV inks and reduce brittleness, rosin resins that have been successfully used in conventional inks can also be used in UV inks, provided that they exhibit sufficient solubility in acrylates, such as described in, for example, U.S. Patent No. 5,212,213 or U.S. Patent No. 7,232,861 and European Patent No. 3433711.

[0012] U.S. Patent No. 5,212,213 refers to the use of fully fumarated rosin and / or fully maleated rosin to provide a higher softening point and enable the production of 100% solid resins. In this invention, due to high temperatures or long dissolution times, there is a higher risk of polymerization during the ink or varnish making process, and thus the temperature is maintained as low as possible while still remaining above the threshold for dissolving the rosin in the acrylate.

[0013] U.S. Patent No. 7,232,851 refers to electron beam and / or UV curable lithographic ink compositions and printing methods that generally use only rosin soluble in acrylate, but this invention requires a rosin that also exhibits good solubility in highly functional acrylates, such as dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate, which are particularly suitable for use in LED inks. Specifically, the rosin used in this invention exhibits good solubility in pentaacrylates and hexaacrylates, such as dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate. As discussed in more detail below, the solubility in these penta- and hexa-functional acrylates is achieved without using high temperatures (i.e., temperatures above 135°C).

[0014] Another issue related to the press performance of UV and LED inks is so-called misting. During the printing process, small ink droplets in the form of mist, caused by the strong centrifugal force of rapidly rotating rollers and the limited cohesive force of the ink, escape from the rapidly operating rollers, contaminate the printing press, and result in frequent large-scale cleaning operations and production stoppages. Typical means for reducing misting are to increase the solid content of the ink by adding fillers or to increase the pigment addition.

[0015] However, high solids often result in adverse effects such as accumulation of ink on rollers and plates caused by aggregation of particles due to the high solids.

[0016] European Patent No. 3434711 mentions the use of rosin esters in energy-curable (EC) inks. Neither LEDs nor aluminum additives are mentioned, nor is the improvement of misting by aluminum additives.

Summary of the Invention

[0017] The object of the present application is to provide an LED-curable offset ink that shows a low tendency to mist in an offset printing press while maintaining excellent press performance and LED drying characteristics.

[0018] The citation or identification of any document in the present application is not an admission that it represents prior art with respect to the present invention.

Brief Description of the Drawings

[0019]

Figure 1

Embodiments for Carrying Out the Invention

[0020] The present invention is further illustrated by, for example, the following sets of embodiments and combinations of embodiments resulting from the dependencies and cross-references shown. In particular, in each example where the scope of an embodiment is mentioned, for example, in the context of terms such as "any one of Methods of Embodiments 1 - 5", all embodiments within this scope are intended to be explicitly disclosed to those skilled in the art, that is, it should be noted that the language of this term should be understood by those skilled in the art as being synonymous with "any one of Methods of Embodiments 1, 2, 3, 4, and 5".

[0021] The present invention relates to one or more acrylates in which 25 to 85% of at least one acrylate is pentaacrylate or hexaacrylate; 0 to 20% of one or more photoinitiators; 5 to 60% of one or more rosin-modified polyester resins having a molecular weight of 5,000 to 35,000 daltons; 0.2 to 5% of one or more aluminum additives; 0.1 to 5% of one or more polymerization stabilizers; 0 to 50% of a colorant and provides a printing ink or varnish composition containing the same.

[0022] The ink or varnish composition according to the present invention is suitable for curing by UV-LED irradiation.

[0023] In one aspect, the present invention relates to one or more acrylates in which 25 to 85% of at least one acrylate is pentaacrylate or hexaacrylate; 0 to 20% of one or more photoinitiators; 5 to 60% of one or more rosin-modified polyester resins having a molecular weight of 5,000 to 35,000 daltons; 0.2 to 5% of one or more aluminum additives; 0.1 to 5% of one or more polymerization stabilizers and provides a varnish composition containing the same.

[0024] In another aspect, the present invention provides an ink composition comprising the varnish of the invention and 0 to 50% of a colorant (preferably 5 to 40% of a colorant). Advantageously, an LED-curable ink containing an aluminum-modified acrylate varnish exhibits excellent lithographic printing performance and a much lower misting tendency while maintaining and even exceeding the performance in a printing press and showing excellent LED curing characteristics.

[0025] The ink is suitable for printing on any substrate for lithography, such as graphic paper, wrapping paper, and packaging applications on cardboard and foil.

[0026] Preferably, the LED-curable ink or varnish of the invention comprises the following materials: 25 to 85% of one or more acrylates, wherein at least one acrylate is pentaacrylate or hexaacrylate; 0.5 to 20% of a photoinitiator; 5 to 60% of a rosin-modified polyester resin having a molecular weight of 5,000 to 35,000 daltons; 0.2 to 5% of an aluminum additive; 0.1 to 5% of a polymerization stabilizer; 0 to 50% of a colorant and.

[0027] Acrylate The (meth)acrylic acid (i.e., (meth)acrylate) monomers suitable for use in the present invention include, in one embodiment, esters of acrylic acid or methacrylic acid having a defined structure.

[0028] A non-limiting list of examples of (meth)acrylate monomers suitable for use in the present invention includes n-octyl acrylate, isooctyl acrylate, n-decyl acrylate, lauryl acrylate, stearyl acrylate, ethylene glycol diacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, dipropylene glycol diacrylate, neopentyl glycol diacrylate, ethoxylated neopentyl glycol diacrylate, propoxylated neopentyl glycol diacrylate, tripropylene glycol diacrylate, bisphenol A diacrylate, ethoxylated bisphenol A diacrylate, bisphenol A diglycidyl ether diacrylate, ethoxylated bisphenol A diacrylate, poly(ethylene) glycol diacrylate, trimethylolpropane triacrylate, ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, propoxylated glycerin triacrylate, ditrimethylolpropane tetraacrylate, pentaerythritol triacrylate, ethoxylated pentaerythritol triacrylate, propoxylated pentaerythritol tetraacrylate, ethoxylated pentaerythritol tetraacrylate, ditrimethylolpropane tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate or mixtures thereof.

[0029] In one embodiment, the LED-curable varnish or ink of the present invention comprises alkoxylated trimethylolpropane triacrylate, pentaerythritol tetraacrylate, alkoxylated pentaerythritol tetraacrylate, ditrimethylolpropane tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, alkoxylated dipentaerythritol hexaacrylate or mixtures thereof.

[0030] In one embodiment, the ink of the present invention may further contain an acrylate oligomer. In one embodiment, the ink of the present invention contains, for example, epoxy acrylate, polyester acrylate, acrylated polyurethane, fatty acid-modified polyester acrylate, acrylated polyether, etc. in order to impart rheology, pigment wetting, transfer, gloss, chemical resistance and other film properties, and has a number average molecular weight of about 400 to 5,000 daltons and an acrylate functionality of 2 or more. It may further contain an acrylated oligomer.

[0031] Preferably, the ink or varnish composition of the present invention contains pentaacrylate or hexaacrylate and at least one other acrylate selected from those described herein. More preferably, the ink or varnish composition of the present invention contains hexaacrylate and at least one other acrylate selected from those described herein.

[0032] Preferably, the ink or varnish composition of the present invention contains dipentaerythritol pentaacrylate or dipentaerythritol hexaacrylate and at least one other acrylate selected from those described herein. More preferably, the ink or varnish composition of the present invention contains dipentaerythritol hexaacrylate and at least one other acrylate selected from those described herein.

[0033] Preferably, the ink or varnish composition of the present invention comprises a hexaacrylate and at least one other acrylate selected from alkoxylated trimethylolpropane triacrylate, pentaerythritol tetraacrylate, alkoxylated pentaerythritol tetraacrylate, ditrimethylolpropane tetraacrylate, dipentaerythritol pentaacrylate, or a mixture thereof. More preferably, the ink or varnish composition of the present invention comprises a dipentaerythritol hexaacrylate and at least one other acrylate selected from alkoxylated trimethylolpropane triacrylate, pentaerythritol tetraacrylate, alkoxylated pentaerythritol tetraacrylate, ditrimethylolpropane tetraacrylate, dipentaerythritol pentaacrylate, alkoxylated dipentaerythritol hexaacrylate, or a mixture thereof.

[0034] Preferably, the ink or varnish composition of the present invention comprises one or more acrylates in which 30 to 70% of at least one acrylate is a pentaacrylate or a hexaacrylate.

[0035] Preferably, the ink or varnish of the present invention comprises 25 to 60% of a pentaacrylate or a hexaacrylate.

[0036] Photoinitiator The radiation-curable ink of the present invention contains a photoinitiator that absorbs in the UVA region of 320 to 400 nm, such as substituted benzophenone, aminoalkylphenone, acylphosphine oxide, and thioxanthone, for example, 4-thiophenylbenzophenone, 4,4'-bis(diethylamino)-benzophenone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one, 2-methyl-1-[4-(methoxythio)-phenyl]-2-morpholinopropan-2-one, diphenylacylphenylphosphine oxide, diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, 2,4,6-trimethylbenzoylethoxyphenylphosphine oxide, ketocoumarin, 2-isopropylthioxanthone, 4-isopropylthioxanthone, 2,4-dimethylthioxanthone, or a mixture thereof.

[0037] Preferably, the ink or varnish composition of the present invention contains one or more photoinitiators selected from phosphine oxide, acetophenone (including aminoacetophenone), aminobenzoate, thioxanthone, and combinations thereof.

[0038] In the case of inks designed for food packaging, preferably, the migrating low molecular weight monomer photoinitiator is minimized or, more preferably, completely replaced with an oligomeric or polymeric photoinitiator such as Omnipol TX, a trademark of IGM resin.

[0039] Preferably, the ink or varnish composition according to the present invention contains 0.5 to 20% of one or more photoinitiators, more preferably 3 to 18% of one or more photoinitiators, and even more preferably 5 to 15% of one or more photoinitiators.

[0040] rosin resin For example, rosin resins such as maleic acid-modified rosin esters or phenolic modified rosin resins are widely used as printing ink vehicles in flexographic inks and gravure inks. Maleic acid-modified rosin esters often exhibit good pigment wetting, gloss retention, color retention, and adhesion, and usually show better solubility in acrylates than phenolic modified rosin esters. Rosin esters can be synthesized from commercially available rosins such as gum rosin, wood rosin, or tall oil rosin, and difunctional acids such as maleic acid, fumaric acid, itaconic acid, in addition to trifunctional or tetrafunctional hydroxy compounds such as glycerin, trimethylolpropane, pentaerythritol. Esters of rosin are commercially available and can be prepared as described in the "Printing Ink Manual", 5th Edition, Blueprint, London. For example, the preparation of maleated rosin esters is specifically described in Example 1 of U.S. Patent Application Publication No. 2007232786. Typically, modified rosin esters are prepared by heating a commercially available rosin (e.g., gum rosin) with a difunctional acid (e.g., maleic acid) and a hydroxy compound (e.g., pentaerythritol) until the desired acid value (also called acid number) is obtained.

[0041] However, while rosin esters are known in the art, the rosin resins for use in the present application must be soluble not only in acrylate in general, but also in highly functional acrylates particularly suitable for use in LED inks such as dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate. As used herein, a rosin resin has good solubility in the highly functional acrylate (particularly dipentaerythritol pentaacrylate or dipentaerythritol hexaacrylate) when a 30 wt% (preferably 40 wt%, even more preferably 50 wt%) solution of the rosin resin in the highly functional acrylate shows no visible precipitation at room temperature (i.e., 20 °C). This can be achieved, for example, by appropriate selection of acids such as maleic acid or maleic anhydride or cyclohexenedicarboxylic dianhydride or methylcyclohexenedicarboxylic dianhydride that provide better solubility, and polyols such as glycerin and trimethylolpropane, and by limiting the molecular weight and softening point. To limit the molecular weight and provide excellent solubility in acrylate, a monofunctional acid such as benzoic acid, methyl benzoic acid, tert-butyl benzoic acid, naphthoic acid or a fatty acid such as linoleic acid can be added to the reaction mixture to control the condensation reaction and the molecular weight.

[0042] Preferably, the rosin resin used in the present invention is derived from i) gum rosin, wood rosin or tall oil rosin; ii) one or more difunctional acids or anhydrides; iii) one or more monofunctional, difunctional, trifunctional or tetrafunctional polyols; and iv) one or more monofunctional acids.

[0043] Preferably, the difunctional acid or anhydride is selected from maleic acid, maleic anhydride, cyclohexenedicarboxylic dianhydride or methylcyclohexenedicarboxylic dianhydride. More preferably, the difunctional acid or anhydride is selected from cyclohexenedicarboxylic dianhydride or methylcyclohexenedicarboxylic dianhydride.

[0044] Preferably, the one or more monofunctional, difunctional, trifunctional or tetrafunctional polyols are selected from glycerin or trimethylolpropane.

[0045] Preferably, the one or more monofunctional acids are selected from benzoic acid, methylbenzoic acid, tert-butylbenzoic acid, naphthoic acid and linoleic acid. More preferably, the one or more monofunctional acids are selected from benzoic acid, methylbenzoic acid and tert-butylbenzoic acid. Even more preferably, the one or more monofunctional acids are benzoic acid.

[0046] Preferably, the rosin resin used in the present invention is derived from i) gum rosin, wood rosin or tall oil rosin; ii) one or more difunctional acids or anhydrides; iii) one or more monofunctional, difunctional, trifunctional or tetrafunctional polyols; and iv) one or more monofunctional acids selected from benzoic acid, methylbenzoic acid, tert-butylbenzoic acid, naphthoic acid and linoleic acid. More preferably, the rosin resin used in the present invention is derived from i) gum rosin, wood rosin or tall oil rosin; ii) one or more difunctional acids or anhydrides; iii) one or more monofunctional, difunctional, trifunctional or tetrafunctional polyols; and iv) one or more monofunctional acids selected from benzoic acid, methylbenzoic acid and tert-butylbenzoic acid.

[0047] Preferably, the rosin resin used in the present invention is derived from i) gum rosin, wood rosin or tall oil rosin; ii) one or more bifunctional acids or anhydrides selected from maleic acid, maleic anhydride, cyclohexenedicarboxylic dianhydride or methylcyclohexenedicarboxylic dianhydride; iii) one or more monofunctional, bifunctional, trifunctional or tetrafunctional polyols; and iv) one or more monofunctional acids selected from benzoic acid, methylbenzoic acid, tert-butylbenzoic acid, naphthoic acid and linoleic acid. More preferably, the rosin resin used in the present invention is derived from i) gum rosin, wood rosin or tall oil rosin; ii) one or more bifunctional acids or anhydrides selected from cyclohexenedicarboxylic dianhydride or methylcyclohexenedicarboxylic dianhydride; iii) one or more monofunctional, bifunctional, trifunctional or tetrafunctional polyols; and iv) one or more monofunctional acids selected from benzoic acid, methylbenzoic acid and tert-butylbenzoic acid.

[0048] Preferably, the rosin resin used in the present invention is derived from i) gum rosin, wood rosin or tall oil rosin; ii) one or more bifunctional acids or anhydrides selected from cyclohexenedicarboxylic dianhydride or methylcyclohexenedicarboxylic dianhydride; iii) one or more monofunctional, bifunctional, trifunctional or tetrafunctional polyols selected from glycerin or trimethylolpropane; and iv) one or more monofunctional acids selected from benzoic acid, methylbenzoic acid and tert-butylbenzoic acid.

[0049] Furthermore, in order to provide a hydrophobic / hydrophilic balance for the lithographic (offset) printing process, the rosin resin shall have some polar acid groups in addition to nonpolar (hydrophobic) rosin units. Typically, a rosin resin with an acid value of 5 to 50 mg KOH / g (preferably an acid value of 10 to 30 mg KOH / g) is suitable. More preferably, the rosin resin has an acid value of 12 to 25 mg KOH / g.

[0050] Furthermore, the softening point of the rosin resin is important. The dropping point is the temperature at which the first drop of the molten substance precipitates from a standardized cup with a specified orifice under controlled test conditions in the furnace. This can be measured using an automated device such as the DP70 manufactured by Mettler Toledo. The temperature range in which the ink or varnish of the invention can be prepared is limited due to the risk of acrylate polymerization at higher temperatures. If the rosin ester has a higher softening point, for example, above 135°C, it is very difficult or takes a very long time to dissolve in acrylate below 100°C. Unlike non-polymer materials, polymers do not dissolve instantaneously, and dissolution is controlled by the relaxation of polymer chains. This means that the polymer must first swell before it can dissolve, which is more difficult below the softening point (Koening et al., "A review of polymer dissolution", Vol. 28, No. 8, August 2003, pp. 1223 - 1270).

[0051] As a result, due to high temperatures or long dissolution times, the risk of polymerization during ink or varnish preparation increases. Preferably, the softening point of the rosin resin is in the range of 70 - 135°C or 85 - 110°C.

[0052] Before use, the compatibility of the rosin resin should be tested to confirm that it has sufficient solubility to prepare the ink or varnish. Typically, the solubility of the rosin resin should be such that a stable ink or varnish is possible in dipentaerythritol pentaacrylate or dipentaerythritol hexaacrylate at a concentration of more than 30 wt% or more than 40%. Stability indicates no resin precipitation at lower storage temperatures and no ink polymerization or varnish polymerization at higher storage temperatures.

[0053] Preferably, the ink or varnish composition of the present invention contains 5 - 50%, preferably 10 - 40%, of the rosin resin.

[0054] Surprisingly, the rosin resin used in the present invention is soluble in pentaacrylate monomers and hexaacrylate monomers (e.g., dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate) without using high temperatures (i.e., temperatures above 135°C). Preferably, the rosin resin is soluble in pentaacrylate monomers and hexaacrylate monomers (e.g., dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate) at 120°C or lower, preferably 100°C or lower.

[0055] Preferably, the rosin resin has a molecular weight of 8,000 to 35,000 Daltons, preferably 10,000 to 35,000 Daltons.

[0056] Rosin resins suitable for this application that exhibit good solubility in dipentaerythritol pentaacrylate or dipentaerythritol hexaacrylate typically have a molecular weight of 5000 - 35000 or 5000 - 30000 Daltons, as measured by size exclusion chromatography; a softening point of 70 - 135°C or 85 - 110°C; and an acid value of 5 - 50 mg KOH / g, 10 - 30 mg KOH / g, or 12 - 25 mg KOH / g. Preferably, the rosin resin has a molecular weight of 5000 - 35000 Daltons, a softening point of 85 - 110°C, and an acid value of 10 - 30 mg KOH / g. More preferably, the rosin resin has a molecular weight of 5000 - 35000 Daltons, a softening point of 85 - 110°C, and an acid value of 12 - 25 mg KOH / g.

[0057] The rosin resin used in the present invention typically has an ethanol number of more than 4 g / 10 g. For example, the rosin resin used in the present invention typically has an ethanol number of 4 - 10 g / 10 g. As understood in the art, the ethanol number (EN) provides a measure of the resin's resistance to ethanol and thus provides an indication of the resin's polarity.

[0058] Aluminum additive Aluminum additives suitable for this application are aluminum alkoxides, aluminum chelates or aluminum carboxylates. Suitable aluminum alkoxides include aluminum monopropoxide, aluminum dipropoxide or aluminum tripropoxide, aluminum monoisopropoxide, aluminum diisopropoxide or aluminum triisopropoxide, aluminum monobutyrate, aluminum dibutyrate or aluminum tributyrate, aluminum monoisobutyrate, aluminum diisobutyrate or aluminum triisobutyrate, or blends thereof. Suitable aluminum chelates include aluminum monoethylacetoacetate chelate with diisopropylate, aluminum diketates and aluminum trichelates with alkyl acetoacetate or alkyl diketone, or blends thereof. Suitable aluminum carboxylates include aluminum carboxylates selected from the group consisting of aluminum triacetate esters or aluminum tripropionate esters and blends thereof.

[0059] Preferably, the aluminum additive is an aluminum chelate. More preferably, the aluminum additive is selected from aluminum monoethylacetoacetate chelate with diisopropylate; aluminum diketates and aluminum trichelates with alkyl acetoacetate or alkyl diketone, and blends thereof.

[0060] Preferably, the aluminum additive is diisopropoxide ethyl acetoacetate (CAS No. 14782-75-3).

[0061] Most of these aluminum additives are commercially available. For better handling of the moisture-sensitive additives (e.g., diisopropylate chelate which can be called alcoholate), and to avoid hydrolysis and disintegration, the aluminum additives can be pre-dissolved in a small amount in an inert solvent such as sunflower oil. Therefore, in a preferred embodiment of the present invention, the aluminum additive is an aluminum alkoxide, aluminum chelate or aluminum carboxylate in an inert solvent. When the aluminum additive is in an inert solvent (such as sunflower oil), the weight ratio of the aluminum additive to the inert solvent is 1:1.

[0062] Suitable inert solvents include mineral oils and vegetable oils such as sunflower oil. Preferably, the inert solvent is sunflower oil.

[0063] Preferably, the aluminum additive is present in sunflower oil at a weight ratio of 1:1.

[0064] Preferably, the aluminum additive is an aluminum chelate in an inert solvent. More preferably, the aluminum additive is an aluminum monoethylacetoacetate chelate with diisopropylate in an inert solvent; an aluminum diketone chelate and an aluminum trichelate with alkyl acetoacetate, alkyl diketone, or a blend thereof.

[0065] Preferably, the aluminum additive is an aluminum chelate in sunflower oil. More preferably, the aluminum additive is an aluminum monoethylacetoacetate chelate with diisopropylate in sunflower oil; an aluminum diketone chelate and an aluminum trichelate with alkyl acetoacetate, alkyl diketone, or a blend thereof.

[0066] Preferably, the aluminum additive is diisopropoxide ethyl acetoacetate in an inert solvent. More preferably, the aluminum additive is diisopropoxide ethyl acetoacetate in sunflower oil.

[0067] In the present application, the aluminum additive can react with hydroxyl groups, carboxyl groups and amine groups in the ink or varnish during the production of the ink or varnish at a high temperature of 80 to 120 °C, which has a positive effect on the rheology of the ink produced therefrom, particularly on the structure or so-called body (viscosity at a low shear rate, i.e., D = 2 1 / s), and affects the cohesion of the ink.

[0068] In the present invention, the aluminum additive is present at 0.2 to 5% of the ink or varnish composition. Preferably, the aluminum additive is present at 0.5 to 5%, more preferably 0.5 to 3% of the ink or varnish composition.

[0069] Preferably, the ink or varnish composition of the present invention contains 0.2 to 5% of the aluminum additive in an inert solvent such as sunflower oil. Preferably, the aluminum additive and the inert solvent are in a weight ratio of 1:1 such that the composition contains 0.1 to 2.5% of the aluminum additive and 0.1 to 2.5% of the inert solvent.

[0070] Polymerization stabilizer (also referred to as polymerization inhibitor in this specification) The ink of the present invention may further contain a stabilizer to ensure good shelf life. Examples of such polymerization inhibitors include nitroso stabilizers such as nitroso-phenylhydroxylamine; phenolic stabilizers such as hydroquinone (HQ), methyl ether hydroquinone (MEHQ), butylhydroxytoluene (BHT) and 2,6-di-tert-butyl-N,N-dimethylamino-p-cresol, phenothiazine stabilizers and nitroso-phenylhydroxylamine stabilizers as well as stabilizers based on copper thiocarbamate and zinc thiocarbamate. This component is useful as a varnish and an ink and, due to the long wavelength absorbing photoinitiator suitable for LED drying, also absorbs visible light and is prone to cause premature polymerization.

[0071] Preferably, the ink or varnish composition contains 0.5 to 5% of one or more polymerization stabilizers.

[0072] Varnish Preparation The varnish of the present invention is prepared, for example, by adding liquid components and stabilizers to a stirring kettle, heating to 80 to 120°C, and then adding solid rosin resin and optional other solid additives. Once the rosin resin is dissolved, an aluminum additive is added, the mixture is stirred at a predetermined time and temperature, filtered, and then can be used to prepare an LED-curable ink. The varnish is characterized by the viscosities at high and low shear rates (D = 50 1 / s and D = 2 1 / s, respectively) measured with a rheometer, and can be further characterized by a vibration experiment to determine the storage modulus, loss modulus, and the ratio of the storage modulus to the loss modulus (tan delta) representing the viscous and elastic parts of the varnish. The lower the tan delta, the higher the reactivity with the aluminum additive. Usually, 0.5 to 5.0% by weight of the aluminum additive is added according to the desired viscosity and rheology of the varnish.

[0073] Preferably, the varnish composition of the present invention has a viscosity of 40 to 150 Pa·s at 23°C and a shear rate D = 50 1 / s, more preferably 60 to 100 Pa·s at 23°C and a shear rate D = 50 1 / s, and even more preferably 60 to 80 Pa·s at 23°C and a shear rate D = 50 1 / s.

[0074] The ink of the invention of the present application can be produced by a two-step process, for example, by preparing a premix and pulverizing it. The premix is prepared by charging the varnish of the invention and further monomers into a stirring kettle, starting the stirring, and then adding solid components such as colorants, fillers and further additives. During mixing, the temperature rises to 40 to 70 °C and the temperature of the mixture is maintained until all the pigments are wetted. Then, the premix is transferred to a grinding process (for example, a three-roll mill or a bead mill) and ground until the desired fineness of grind, measured by a grindometer (for example, an NPIRI gauge), is achieved.

[0075] Colorant The ink of the present invention may also contain one or more colorants in the form of dyes or pigments dispersed therein. Pigments suitable for use in the present invention include conventional organic or inorganic pigments.Representative pigments can be selected from the group consisting of, for example, Pigment Yellow 1, Pigment Yellow 3, Pigment Yellow 12, Pigment Yellow 13, Pigment Yellow 14, Pigment Yellow 17, Pigment Yellow 63, Pigment Yellow 65, Pigment Yellow 73, Pigment Yellow 74, Pigment Yellow 75, Pigment Yellow 83, Pigment Yellow 97, Pigment Yellow 98, Pigment Yellow 106, Pigment Yellow 111, Pigment Yellow 114, Pigment Yellow 121, Pigment Yellow 126, Pigment Yellow 127, Pigment Yellow 136, Pigment Yellow 138, Pigment Yellow 139, Pigment Yellow 174, Pigment Yellow 176, Pigment Yellow 188, Pigment Yellow 194, Pigment Orange 5, Pigment Orange 13, Pigment Orange 16, Pigment Orange 34, Pigment Orange 36, Pigment Orange 61, Pigment Orange 62, Pigment Orange 64, Pigment Red 2, Pigment Red 9, Pigment Red 14, Pigment Red 17, Pigment Red 22, Pigment Red 23, Pigment Red 37, Pigment Red 38, Pigment Red 41, Pigment Red 42, Pigment Red 48:2, Pigment Red 53:1, Pigment Red 57:1, Pigment Red 81:1, Pigment Red 112, Pigment Red 122, Pigment Red 170, Pigment Red 184, Pigment Red 210, Pigment Red 238, Pigment Red 266, Pigment Blue 15, Pigment Blue 15:1, Pigment Blue 15:2, Pigment Blue 15:3, Pigment Blue 15:4, Pigment Blue 61, Pigment Green 7, Pigment Green 36, Pigment Violet 1, Pigment Violet 19, Pigment Violet 23, Pigment Black 7, anatase or rutile modified titanium dioxide, zinc oxide, barium sulfate, zinc sulfide, lithopone or calcium carbonate.

[0076] Preferably, the ink composition according to the present invention contains 5 to 40% of one or more colorants, more preferably 10 to 30% of one or more colorants.

[0077] Additive The LED-curable ink of the present invention may further contain additives typically used in the present invention to modify the flow, surface tension, gloss, flow, pigment wetting and abrasion resistance of the cured coating or printed ink. Such additives contained in the ink or varnish are typically surfactants, waxes (e.g., PE waxes), storage life stabilizers, etc., and combinations thereof. These additives can function as leveling agents, storage life stabilizers, wetting agents, slip agents, fluidizing agents, dispersants and degassing agents. In some embodiments, the additives include fluorocarbon surfactants, silicones and organic polymer surfactants. Examples include the Tegorad product line (Tegorad is a trademark and is a commercial product of Tego Chemie, Essen, Germany) and the Solsperse product line (Solsperse is a trademark and is a commercial product of the Lubrizol Company).

[0078] The LED-curable ink of the present invention may further contain extenders typically used in the art such as clay, talc (e.g., micronized talc), calcium carbonate, magnesium carbonate or silica to adjust water uptake and color strength. The ink of the present invention may further contain additives for modifying properties such as the surface tension, gloss, flow, pigment wetting and abrasion resistance of the printed ink.

[0079] Preferably, the ink or varnish composition of the present invention contains 5% by weight or less of vegetable oil and / or mineral oil. More preferably, the ink or varnish composition of the present invention contains 3% by weight or less, even more preferably 1.5% by weight or less of vegetable oil and / or mineral oil.

[0080] Unless otherwise specified, "vegetable oil" and "mineral oil" refer to non-functionalized oils. That is, unless the vegetable oil is described as being functionalized (e.g., acrylated epoxidized vegetable oil), the term "vegetable oil" refers to an oil derived from the seeds or other parts of fruits that have not been functionalized (e.g., by a chemical reaction) to include moieties that can participate in the polymerization process. Similarly, the term "mineral oil" refers to a petroleum hydrocarbon oil that has not been functionalized (e.g., by a chemical reaction) to include moieties that can participate in the polymerization process.

[0081] Preferably, the ink or varnish composition of the present invention contains 5% by weight or less of a vegetable oil selected from soybean oil, linseed oil, castor oil, or a combination thereof. More preferably, the ink or varnish composition of the present invention contains 3% by weight or less, and even more preferably 1.5% by weight or less, of a vegetable oil selected from soybean oil, linseed oil, castor oil, or a combination thereof.

[0082] Preferably, the ink or varnish composition of the present invention contains 5% by weight or less of mineral oil. More preferably, the ink or varnish composition of the present invention contains 3% by weight or less, and even more preferably 1.5% by weight or less, of mineral oil.

[0083] Preferably, the ink or varnish composition of the present invention contains 15% by weight or less of an organic solvent typically used in UV-curable ink compositions. For example, the ink of the varnish composition of the present invention contains 15% by weight or less of an alcohol solvent such as methanol, ethanol, propanol, isopropyl alcohol, butanol, ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, glycerin, or a combination thereof.

[0084] Typically, the ink of the present invention is measured with a commercially available cone-plate rheometer such as the Physika RCS 300 manufactured by Anton Paar of Germany, which is a typical stress rheometer and widely used in quality control and research and development, and exhibits a viscosity of about 5 to 100 Pa·s at 23°C and a shear rate D = 50 1 / s. Preferably, the viscosity of the ink is about 40 to 60 Pa·s at a temperature of 23°C and a shear rate D = 50 1 / s.

[0085] Typical values of the ink flow (tilted plate flow) are about 3 to 15 cm after 15 minutes, measured with a tilted aluminum plate using 1 cc of ink.

[0086] Preferably, the ink of the present invention exhibits a tack of 200 to 450 units measured using the "Tack-o-Scope" device (model 2001) manufactured by IGT testing systems of the Netherlands, which is known to those skilled in the art. More preferably, the tack is about 230 to 350 units. Darker colors usually have a higher adjusted tack.

[0087] The radiation-curable ink of the present invention can be cured by LED light. The wavelength of the applied LED irradiation can be in the range of about 200 to 500 nm or about 320 to 400 nm. Preferably, the LED energy is in the range of about 30 to 1000 mJ / cm 2 or in the range of about 50 to 500 mJ / cm 2 The values are measured with a calibrated radiometer having a good response in the relevant UVA region, such as the Powerpuck II manufactured by EIT. Furthermore, the LED source can be appropriately selected according to the absorption spectrum of the radiation-curable composition. Furthermore, the ink of the present invention can be cured under inert conditions or as an ink laminated with a plastic foil.

[0088] In another embodiment, the photoinitiator can be removed and the varnishes and inks of the present invention can be cured by electron beam radiation (EB) (i.e., the ink or varnish composition contains 0% photoinitiator). Commercially, EB dryers are available, for example, from Energy Science, Inc., Wilmington, Massachusetts, USA, or from Advanced Electron Beams Inc. (AEB), Wilmington, Massachusetts, USA. The absorbed energy, also known as the dose, is measured in units of kilograys (kGy), where 1 kGy is equal to 1,000 joules per kilogram. Typically, for complete curing, the electron beam dose must be in the range of 10 kGy to about 40 kGy. In the radiation-curable compositions of the present invention, a radiation dose of 20 - 30 kGy at an oxygen level of less than 200 ppm is usually sufficient to obtain a dry solvent-resistant ink.

[0089] Unless otherwise specified, all percentages (%) are by weight.

[0090] Substrate The substrate to be printed can be composed of any typical substrate material such as paper, plastic, metal, and composite materials.

[0091] Test method Molecular weight Typically, the molecular weight can be measured by techniques known in the art such as gel permeation chromatography. For example, molecular weight determination can be performed in a Hewlett-Packard 1050 series HPLC system equipped with two GPC Ultrastyragel columns (5 μm mixed, 300 mm × 19 mm, Waters Millipore Corporation, Milford, Massachusetts, USA) of 103 Å and 104 Å, using THF as the mobile phase. The molecular weight can be calculated by comparison with polystyrene standards. Those skilled in the art will understand that this definition of molecular weight typically applies to polymeric materials that have a molecular weight distribution. Usually, unless otherwise specified, the reported molecular weight (or average molecular weight) is the weight average molecular weight (Mw).

[0092] Acid value of rosin resin Weigh 0.2 - 1.0 g of the sample into a clean 50 ml Erlenmeyer flask. Dissolve the sample in acetone (10 - 20 ml). Carefully check whether all the sample materials have dissolved. Add 3 - 5 drops of 1% alcoholic phenolphthalein solution. More indicator solution may be required for the colored solution. Titrate with standardized 0.1 N alcoholic potassium hydroxide (KOH) to the first pink color that persists for 15 seconds. Record the number of ml of the KOH solution used. Calculation:

Number

[0093] Softening point of rosin resin Mettler dropping softening point (MDSP): The softening point can be measured using an automated softening point detector DP70 manufactured by Mettler Toledo. Alternatively, the softening point is determined by the Durand method: Place 3 grams of rosin resin in a 17×50 mm test tube and heat to melt the resin. After cooling the resin to room temperature, add 50.0 g of mercury to the tube and insert a thermometer into the mercury. Heat the tube in a bath at a rate of approximately 2 °C / min. The temperature (°C) at which the resin first appears on the surface of the mercury is taken as the softening point.

[0094] Number of ethanol Unless otherwise specified, the ethanol number can be measured by weighing 10 g of the test resin in an Erlenmeyer flask. Next, the resin is dissolved in 50 g of toluene at a high temperature of 80 °C or lower. Once the resin is completely dissolved, the solution is cooled to room temperature (23 °C), and the Erlenmeyer flask is weighed to obtain "Weight 1" in grams. Place the Erlenmeyer flask on a single white piece of paper with text on it. Then, while stirring, add ethanol dropwise to the Erlenmeyer flask at room temperature until the solution becomes turbid and the text on the paper can no longer be seen. When the text can no longer be seen, stop the titration and weigh the Erlenmeyer flask again to obtain "Weight 2" in grams. Next, calculate the ethanol number by subtracting "Weight 1" from "Weight 2" and quote it as g / 10 g (i.e., grams of ethanol per 10 grams of resin).

[0095] Fineness of Ink Grind Ensure that the grind gauge (25 μm / 0 - 10 NIPRI) is clean and dust-free and must be wiped with a cloth soaked in solvent before starting the test. Apply the paint to both channels at the 25 μm mark. Ensure that the color sample contains no skin or larger particles. The grind gauge block should be placed on a flat surface that does not slide underground. Place the doctor blade vertically with both hands on the grind gauge block, perpendicular to the grind gauge block. Then, slowly pull the paint down to the end of the grind gauge. Press the blade against the grind gauge so that the left and right inks are almost completely removed. Record the μm reading of the grind gauge where at least 4 scratches made by larger ink particles appear.

[0096] Viscosity Unless otherwise specified, the viscosities of the varnish and ink were measured using a Physika 300 cone-plate rheometer manufactured by Anton Parr GmbH at a shear rate D = 2 to 100 1 / s. Record the viscosity values (Pa·s) at shear rates D = 2 1 / s (low shear) and D = 50 (high shear). Unless otherwise specified, the viscosity was measured at a shear rate D = 50 1 / s and 23°C.

[0097] Tack Tack is measured using a calibrated "Tack-o-Scope" instrument (model 2001) manufactured by IGT Testing Systems of the Netherlands. Place 1 ml of ink on an EPDM rubber dispensing roller at 30°C and dispense it for 90 seconds at a roller speed of 50 rpm, then for 30 seconds at 300 rpm. Then obtain the tack value at a roller speed of 150 rpm.

[0098] Ink flow Flow is measured using a vertically placed aluminum plate with 1 ml of ink placed on it. Record the distance (cm) that the ink has flowed down the plate after 15 minutes.

[0099] Press performance and verification of the ink of the invention To further verify the press performance and printing performance of the ink of the invention against the comparative ink, the ink was printed on a "Man Roland 700" 4-color sheet offset UV printing press equipped with two LED dryers (output: 17W / cm at a wavelength of 385 - 395nm) manufactured by AMS. The printing test format (driving force of the printing plate) is a multicolor design with various images, reflecting the possible problems in offset printing (e.g., high ink coverage, low ink coverage, gray shades, color strength, sharp printing, etc.). The special images used are provided by FOGRA, a research institution for graphic arts in Munich, Germany. The target optical densities are black = 1.75; cyan = 1.40; magenta = 1.40; yellow = 1.30. For the printing test, graphic paper Arto Magic Gloss with a basis weight of 130 g / m 2 ) was selected. 2

[0100] The press performance is evaluated by the printer using a scoring system. 100 points means excellent performance. For each printing problem that occurs during printing, the printer subtracts points. Finally, all the remaining points are totaled to obtain the final score. The tests include LED drying performance, print quality, and performance during printing, which are detailed below.

[0101] Test and evaluate the drying characteristics, solvent resistance, permanganate contamination, and ink back transfer of the LED ink.

[0102] Solvent resistance Solvent resistance is evaluated by rubbing the cured print with a wet cotton swab soaked in isopropanol on the ink until the ink layer is rubbed off. The more friction required to rub off the ink, the better the solvent resistance and curing, and the higher the score. This test stops at 100 rubs to show that a nearly complete curing result gives 100 points. The worst score is the solvent resistance for 0 - 5 rubs, and 20 points are subtracted from 100 for each color.

[0103] Potassium permanganate staining Place a drop of potassium permanganate aqueous solution (5%) on the selected color area on the printed and LED - dried substrate for 5 seconds. Then wipe off the droplet and measure the optical density of the remaining stain. The darker the color (density) of the stain, the more uncured residual double bonds are present in the dried color. No stain means no points are deducted, and if the optical density of the formed spot exceeds 0.25, 25 points are deducted from 100.

[0104] Back - transfer resistance After LED drying, place the counter - paper on the printing surface and apply 10 tons / cm in the printing press 2Press it. Then, take out the paper and inspect for ink back transfer on the counter paper. Ink back transfer without any is regarded as excellent, and ink back transfer exceeding 0.2 optical density is regarded as a bad result. If there is no ink back transfer, the score is not deducted, and the worst score is the back transfer density exceeding 0.2, and 20 points per ink will be deducted from 100. Table 1 shows more detailed back transfer scoring.

Table 1

[0105] Regarding the quality of printing, evaluate the rub resistance and gloss.

[0106] Rub resistance Place the ink printed matter on a "Southland" friction tester and rub the surface with counter paper for a specified period. Visually inspect the amount of ink rubbed off and give scores by comparison from excellent to worst. The less the ink damage and the amount of ink rubbed off, the higher the score. The results are evaluated from 0 (best) to 10 (worst). 0 or 1 means no score deduction, and 10 means -20 points per ink from 100. Table 2 shows more detailed rub resistance scoring.

Table 2

[0107] Gloss Gloss is measured at 60° with a BYK Micro Glossmeter. The higher the gloss, the better the score. One gloss unit of the glossmeter is equal to one score. The average of all four process colors is recorded.

[0108] Evaluate the ink performance during printing by ink duct flow, mixing, and overall lithographic printing performance.

[0109] Duct flow The duct flow is evaluated based on how well the ink can exit the ink duct without additional forced agitation. If the ink does not exit the ink duct properly, the transfer via the ink roller system may be slowed or interrupted. The ink duct flow is evaluated by comparison on a scale of 0 (best) to 5 (worst) by a printer skilled in the art. The better the ink duct flow, the higher the score. In the case of excellent flow from the ink duct, the score is not deducted from 100, and in the case of worse flow, 22 points are deducted from 100 for each ink. Table 3 shows more detailed duct flow scoring.

Table 3

[0110] Misting Misting can be a serious problem during a printing job as it contaminates the printing press and results in frequent production stops for cleaning the press. Furthermore, when small acrylate mist droplets enter the air, this can also cause health hazards. Even though printing settings and roller diameter can play a role, the chemical properties of the ink are considered an important factor. Misting is determined by placing a blank paper substrate in close proximity to the selected roller, and the ink mist originating from the roller is deposited on the blank paper over a specified time. Then, the papers with the attached ink mist are visually compared or measured with a densitometer to determine the amount of ink on the paper. The less ink mist deposited on the paper, the better the "misting" performance and the higher the score. Misting is evaluated on a scale of 0 (best) (meaning no score deduction) to 5 (worst) (-20 points are deducted from 100 for each color). Table 4 shows more detailed misting scoring.

Table 4

[0111] Offset printing performance The overall lithographic performance is evaluated by the main requirements and printing problems that can occur in a sheet-fed offset printing press, such as, for example, ink / water balance, background soiling, picking, soiling by another color, over-emulsification, ink in the dampening train, flaming, ink piling, etc., as described below. These problems are known to those skilled in the art, and a score based on a comparison score and the procedure described later is given. Finally, the scores of the individual scoring results related to lithography are summed to obtain the overall lithographic performance score. Below, the individual requirements of lithographic performance are described.

[0112] Ink / water balance The goal is to print the offset ink with the minimum amount of dampening water while the printing plate is still moving freely. The ink / water balance is also described by the expression "water width". This is specified by the maximum possible range of the ink and water settings during printing under which the ink still flows stably. The ink / water balance is evaluated by the printer from 0 to 5, where 0 (best) means no score deduction, and 5 (worst) means a 20-point deduction per color from 100.

[0113] Background soiling Background soiling is the inability of the dampening water to keep the non-image areas of the lithographic plate clean. Background soiling is evaluated by the printer from 0 to 5, where 0 (best) means no background soiling and no score deduction, and 5 (worst) means a 20-point deduction per color from 100.

[0114] Picking Picking means that the ink peels off the fibers from the paper substrate or peels off the paper coating. Picking is evaluated by the printer from 0 to 5, where 0 (best) means no picking and no score deduction, and 5 (worst) means a 20-point deduction per color from 100.

[0115] Soiling by another color The ink may be contaminated by another ink during the printing test, which may cause a detectable color shift on the printed matter due to a shift in the colorimetric analysis data. The stain is evaluated by the printer on a scale of 0 to 5, where 0 (best) indicates no stain and there is no point deduction, and 5 (worst) indicates a 20-point deduction per color from 100.

[0116] Overemulsification If the ink absorbs too much water, it may produce a fur-like ink coating formed on the ink train roller. Overemulsification is evaluated by the printer on a scale of 0 to 5, where 0 (best) indicates no overemulsification and there is no point deduction, and 5 (worst) indicates a 20-point deduction per color from 100.

[0117] Ink in the damping train The ink is detected visually in the damping train and evaluated by the printer on a scale of 0 to 5, where 0 (best) indicates no ink in the damping train and there is no point deduction, and 5 (worst) indicates a 20-point deduction per color from 100.

[0118] Framing Framing refers to the ink being visually visible outside and around the intended printing area. Framing is evaluated by the printer on a scale of 0 to 5, where 0 (best) indicates no framing and there is no point deduction, and 5 (worst) indicates a 20-point deduction per color from 100.

[0119] Ink piling The ink may accumulate in areas of the rollers, blankets, and plates, causing dry accumulation of the ink. Piling is evaluated by the printer on a scale of 0 to 5, where 0 (best) indicates no piling and there is no point deduction, and 5 (worst) indicates a 20-point deduction per color from 100.

[0120] As described above, the scoring points of each test result are summed to obtain the overall final score. For better visual understanding, the individual results can be shown in a spider diagram.

[0121] As shown in FIG. 1, the spider chart illustrates the ink performance scores of Examples 2A to 5A of the invention versus the comparative examples. The actual score numbers are also shown in the examples.

[0122] The present invention is further illustrated by the following numbered paragraphs.

[0123] 1. One or more acrylates of 1.25 to 85% and; 0 to 20% of one or more photoinitiators and; 5 to 60% of one or more rosin-modified polyester resins and; 0.2 to 5% of one or more aluminum additives and; 0.1 to 5% of one or more polymerization stabilizers and; 0 to 50% of a colorant and a printing ink or varnish composition containing the same.

[0124] 2. The composition according to paragraph 1, which is curable by UV-LED irradiation.

[0125] 3. The composition according to paragraph 1 or 2, containing 0.5 to 20% of one or more photoinitiators.

[0126] 4. The composition according to paragraph 1, wherein the photoinitiator is removed and the composition can be cured by electron beam irradiation.

[0127] 5. The composition according to the above paragraphs, which is an offset printing ink or varnish.

[0128] 6. The composition according to any of the above paragraphs, wherein at least one of the photoinitiators is selected from the group consisting of thioxanthone, acylphosphine oxide, aminobenzophenone, aminoalkylphenone, ketocoumarin or mixtures thereof.

[0129] 7. The composition according to any of the preceding paragraphs, wherein the aluminum additive is selected from the group consisting of aluminum alkoxides, aluminum chelates, aluminum carboxylates, or blends thereof.

[0130] 8. The composition according to paragraph 7, wherein the aluminum additive is an aluminum alkoxide selected from the group consisting of aluminum monopropoxide, aluminum dipropoxide, or aluminum tripropoxide; aluminum monoisopropoxide, aluminum diisopropoxide, or aluminum triisopropoxide; aluminum monobutyrate, aluminum dibutyrate, or aluminum tributyrate; aluminum monoisobutyrate, aluminum diisobutyrate, or aluminum triisobutyrate, and blends thereof.

[0131] 9. The composition according to paragraph 7, wherein the aluminum additive is an aluminum chelate selected from the group consisting of aluminum monoethylacetoacetate chelate with diisopropylate; aluminum diketates and aluminum trichelates with alkyl acetoacetates or alkyl diketones, and blends thereof.

[0132] 10. The composition according to paragraph 7, wherein the aluminum additive is an aluminum carboxylate selected from the group consisting of aluminum triacetate ester or aluminum tripropionate ester, and blends thereof.

[0133] 11. The composition according to any one of paragraphs 1 to 7 or 9, wherein the aluminum additive is aluminum diisopropoxide ethyl acetoacetate.

[0134] 12. The composition according to any of the preceding paragraphs, wherein the rosin-modified polyester resin is derived from a source selected from the group consisting of gum rosin, tall oil rosin, monofunctional, difunctional, trifunctional or tetrafunctional polyols, monofunctional, difunctional, trifunctional or tetrafunctional acids or anhydrides, and blends thereof.

[0135] 13. The composition according to any one of paragraphs 1 to 11, wherein the rosin-modified polyester resin is derived from a source selected from the group consisting of gum rosin, maleic anhydride, fumaric acid, glycerin, pentaerythritol and blends thereof.

[0136] 14. The composition according to any one of paragraphs 1 to 11, wherein the rosin-modified polyester resin is derived from a source selected from the group consisting of tetrahydrophthalic anhydride, glycerin, aromatic monofunctional acids, monofunctional alcohols and blends thereof.

[0137] 15. The composition according to any of the preceding paragraphs, wherein the rosin-modified polyester resin exhibits a molecular weight of 2,000 to 100,000 Daltons.

[0138] 16. The composition according to any of the preceding paragraphs, wherein the rosin-modified polyester resin has an acid value of 5 to 50 mg KOH / g.

[0139] 17. The composition according to any of the preceding paragraphs, wherein the softening point of the rosin is in the range of 70 to 135 °C or 85 to 110 °C.

[0140] 18. An LED-curable offset ink or coating composition that is the composition according to any one or more of paragraphs 1 to 17, or contains this.

[0141] 19. The composition according to paragraph 18, containing one or more colorants.

[0142] A composition according to paragraph 18 or 19, comprising 20.25 to 85% of the varnish described in any one or more of paragraphs 1 to 17.

[0143] 21. A composition according to any of the preceding paragraphs, showing an improvement of 5% or more in ink and press performance scores compared to a comparative example without an aluminum additive.

[0144] 22. A composition according to any of the preceding paragraphs, showing an improvement of 10% or more in ink and press performance scores compared to a comparative example without an aluminum additive.

[0145] 23. A composition according to any of the preceding paragraphs, showing an improvement of 15% or more in ink and press performance scores compared to a comparative example without an aluminum additive.

[0146] 24. A printed article comprising the composition according to any one or more of paragraphs 1 to 23.

[0147] 25. A method for preparing a printed matter, applying a composition according to any one or more of paragraphs 1 to 23 to a substrate by offset printing; curing the composition by UV-LED or electron beam and a method comprising.

[0148] The present invention has been described in detail including its various embodiments. However, it will be understood by those skilled in the art that, in view of the present disclosure, modifications and / or improvements of the present invention can be made within the scope and spirit of the present invention.

Examples

[0149] The present invention is further illustrated by the following non-limiting examples for further explaining the present invention, and these examples are not intended to limit the scope of the present invention and should not be construed as such.

[0150] Rosin solubility Before preparing the varnishes and ink compositions of the invention, the solubilities of various rosin resins were determined. As can be seen from the data in Table 5 below, rosin resins having molecular weights of 50,000 daltons and 40,000 daltons are soluble in di-trimethylolpropane tetraacrylate (DiTMTPA), but not soluble in dipentaerythritol hexaacrylate (DPHA). Rosin is soluble in dipentaerythritol hexaacrylate, which is a hexa-functional acrylate, only when the molecular weight is reduced. [Table 5]

[0151] The inks and comparative inks of the invention of this application were prepared in a two-step process by making a premix at 40 - 60 °C as described, and then grinding with a three-roll mill until an appropriate pigment particle size (less than 10 μm for bulk particles) was achieved. After the grinding was completed, the inks were ready for printing. The inks of the invention and the comparative inks exhibit a viscosity of 40 - 60 Pa·s, a gradient plate flow of 3 - 15 cm, and a tack of 230 - 330 units. [Table 6]

[0152] The varnish of Comparative Example 1B exhibits a viscosity of about 65 Pa·s and shows nearly Newtonian behavior, while the varnish of Example 1A of the invention has a slightly higher viscosity of about 75 Pa·s and has a higher viscosity at low shear rates ("more structured"). [Table 7] [Table 8] [Table 9]

Table 10

[0153] Table 11 shows a summary of the performance scores of Examples 2A - 5A of the invention versus Comparative Examples 2B - 5B.

Table 11

[0154] Table 11 clearly shows that the aluminum additive improves the overall performance (especially the offset printing performance) of the inks of the invention and reduces misting (higher score) compared to the comparative inks. In the examples, the aluminum additive is incorporated into the varnish, but it is understood that aluminum can be equally easily added directly to the ink itself.

[0155] For better visual understanding, the individual results can be shown in a spider diagram. The spider diagram shows the ink performance scores of Examples 2A - 5A of the invention versus Comparative Examples 2B - 5B.

[0156] In the spider diagram of Figure 1, it can be clearly observed that the four - color ink set of the invention containing the aluminum additive (outer curve shape) covers more plot space than the comparative ink set (inner curve shape), which means that it is a better - functioning ink with respect to misting, offset printing performance, and ink drying, especially as evaluated by the solvent resistance and back - transfer tests.

[0157] The present invention has been described in detail including its various embodiments. However, it will be understood by those skilled in the art that, in view of the present disclosure, modifications and / or improvements of the present invention that fall within the scope and spirit of the present invention can be made.

Claims

1. 25 to 85% of one or more acrylates, wherein at least one acrylate is a pentaacrylate or a hexaacrylate; 0 to 20% of one or more photoinitiators; 5 to 60% of one or more rosin-modified polyester resins having a molecular weight of 5,000 to 35,000 daltons; 0.2 to 5% of one or more aluminum additives; 0.1 to 5% of one or more polymerization stabilizers; 0 to 50% of a colorant and a printing ink or varnish composition containing the same.

2. The composition according to claim 1, wherein the rosin-modified polyester resin has an acid value of 10 to 30 mgKOH / g.

3. The composition according to claim 1 or 2, wherein the rosin-modified polyester resin has a softening point of 85 to 110°C.

4. The composition according to any one of claims 1 to 3, wherein the rosin-modified polyester resin has a molecular weight of 5,000 to 35,000 daltons, an acid value of 10 to 30 mgKOH / g, and a softening point of 85 to 110°C.

5. The composition according to any one of claims 1 to 4, containing 5% or less of vegetable oil and / or mineral oil.

6. The composition according to any one of claims 1 to 5, wherein at least one acrylate is a pentaacrylate.

7. The composition according to claim 6, wherein the pentaacrylate is dipentaerythritol pentaacrylate.

8. The composition according to any one of claims 1 to 5, wherein at least one acrylate is a hexaacrylate.

9. The composition according to claim 8, wherein the hexaacrylate is dipentaerythritol hexaacrylate.

10. The composition according to any one of claims 1 to 9, which is curable by UV-LED irradiation.

11. The composition according to any one of claims 1 to 10, comprising 0.5 to 20% of one or more photoinitiators.

12. The composition according to any one of claims 1 to 10, which contains 0% of a photoinitiator (i.e., the composition does not contain a photoinitiator) and is curable by electron beam irradiation.

13. The composition according to claim 12, which is an offset printing ink or varnish.

14. The composition according to any one of claims 1 to 11 or 13, wherein at least one of the photoinitiators is selected from the group consisting of thioxanthone, acylphosphine oxide, aminobenzophenone, aminoalkylphenone, ketocoumarin, or a mixture thereof.

15. The composition according to any one of claims 1 to 14, wherein the aluminum additive is selected from the group consisting of aluminum alkoxide, aluminum chelate, aluminum carboxylate, or a blend thereof.

16. The aluminum additive is (a) aluminum monopropyloxide, aluminum dipropyloxide, or aluminum tripropyloxide; aluminum monoisopropyloxide, aluminum diisopropyloxide, or aluminum triisopropyloxide; aluminum monobutyrate, aluminum dibutyrate, or aluminum tributyrate; aluminum monoisobutyrate, aluminum diisobutyrate, or aluminum triisobutyrate, and aluminum alkoxides selected from the group consisting of blends thereof; (b) an aluminum mono-ethylacetoacetate chelate with diisopropylate; an aluminum chelate selected from the group consisting of aluminum diketates and aluminum trichelates with alkyl acetoacetates or alkyl diketones, and blends thereof; or (c) an aluminum carboxylate selected from the group consisting of aluminum triacetate esters or aluminum tripropionate esters, and blends thereof The composition according to claim 15, which is as described above. **Claim 17** The composition according to any one of claims 1 to 16, wherein the aluminum additive is aluminum diisopropoxide ethylacetoacetate. **Claim 18** The composition according to any one of claims 1 to 17, wherein the aluminum additive is in an inert solvent, and the inert solvent is selected from mineral oil or vegetable oil. **Claim 19** The composition according to claim 18, wherein the inert solvent is sunflower oil. **Claim 20** The composition according to claim 19, wherein the aluminum additive is aluminum diisopropoxide ethylacetoacetate in sunflower oil. **Claim 21** The rosin-modified polyester resin is (a) a source selected from the group consisting of gum rosin, tall oil rosin, monofunctional, bifunctional, trifunctional or tetrafunctional polyols, monofunctional, bifunctional, trifunctional or tetrafunctional acids or anhydrides, and blends thereof; (b) a source selected from the group consisting of gum rosin, maleic anhydride, fumaric acid, glycerin, pentaerythritol, and blends thereof; or (c) a source selected from the group consisting of tetrahydrophthalic anhydride, glycerin, aromatic monofunctional acids, monofunctional alcohols, and blends thereof The composition according to any one of claims 1 to 20, which is derived from the above. Claim 22 The rosin-modified polyester resin is i) gum rosin, wood rosin or tall oil rosin; ii) one or more bifunctional acids or anhydrides selected from maleic acid, maleic anhydride, cyclohexenedicarboxylic dianhydride or methylcyclohexenedicarboxylic dianhydride; iii) one or more monofunctional, bifunctional, trifunctional or tetrafunctional polyols selected from glycerin or trimethylolpropane; and iv) derived from one or more monofunctional acids selected from benzoic acid, methylbenzoic acid, tert-butylbenzoic acid, naphthoic acid and linoleic acid, The composition according to any one of claims 1 to 21. Claim 23 The rosin-modified polyester resin is i) gum rosin or tall oil rosin; ii) one or more bifunctional acids or anhydrides selected from cyclohexenedicarboxylic dianhydride or methylcyclohexenedicarboxylic dianhydride; iii) one or more monofunctional, bifunctional, trifunctional or tetrafunctional polyols selected from glycerin or trimethylolpropane; and iv) derived from one or more monofunctional acids selected from benzoic acid, methylbenzoic acid, tert-butylbenzoic acid, naphthoic acid and linoleic acid, The composition according to claim 22. Claim 24 The rosin-modified polyester resin is i) gum rosin or tall oil rosin; ii) one or more bifunctional acids or anhydrides selected from cyclohexenedicarboxylic dianhydride or methylcyclohexenedicarboxylic dianhydride; iii) one or more monofunctional, bifunctional, trifunctional or tetrafunctional polyols selected from glycerin or trimethylolpropane; and iv) derived from benzoic acid, The composition according to claim 22 or 23. Claim 25 (a) The rosin-modified polyester resin exhibits a molecular weight of 8,000 to 35,000 daltons; and / or (b) The rosin-modified polyester resin has an acid value of 12 to 25 mg KOH / g, The composition according to any one of claims 1 to 24.

26. The composition according to any one of claims 1 to 25, wherein the rosin-modified polyester has an ethanol number of more than 4 g / 10 g, preferably an ethanol number of 4 to 10 g / 10 g.

27. An LED-curable offset ink or coating composition which is or contains the varnish composition according to any one or more of claims 1 to 26.

28. The ink or coating composition according to claim 27, comprising 5 to 40% of one or more colorants.

29. The ink or coating composition according to claim 27 or 28, comprising 25 to 85% of the composition according to any one or more of claims 1 to 26.

30. The composition according to any one of claims 1 to 29, showing an improvement of 5% or more in ink and press performance scores as compared with a comparative example not containing an aluminum additive, preferably showing an improvement of 10% or more in ink and press performance scores as compared with a comparative example not containing an aluminum additive, and more preferably showing an improvement of 15% or more in ink and press performance scores as compared with a comparative example not containing an aluminum additive.

31. A printed article comprising the composition according to any one or more of claims 1 to 30.

32. A method for preparing a printed matter, applying the composition according to any one or more of claims 1 to 30 to a substrate by offset printing; curing the composition by UV-LED or an electron beam and a method comprising the above.

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