LED-curable offset ink containing aluminum additives

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 composition according to the present invention, which is 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 prior art for 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-described 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, UV-LED inks, like UV inks, often exhibit poor lithographic performance compared to conventional inks based on vegetable or mineral oils. One reason for this behavior is the high polarity of acrylates relative to oil, which makes UV-LED inks more polar, thereby potentially negatively impacting the lithographic process and dampening water interaction.

[0008] Another drawback of UV-LED technology can be poor surface curing due to oxygen inhibition. Oxygen inhibition refers to the fact that oxygen, as a biradical, readily reacts with the radicals formed by the photoinitiator or radicals on the monomer or growing polymer chain, inactivating them, usually as peroxide derivatives. This can result in insufficient drying on ink or coating surfaces where oxygen is dominant. This is particularly problematic with commercially available long-wavelength UV-LED light dryers that emit in the 365–405 nm range, as they lack shorter wavelengths that would be very helpful for good surface curing and activation of photoinitiator radicals on or near the surface.

[0009] This is often counteracted by using highly reactive polyfunctional monomers, such as dipentaerythritol hexaacrylate, because it is more favorable in terms of polymerization rate than oxygen-inhibited processes.

[0010] However, the widespread use of polyfunctional monomers (such as dipentaerythritol hexaacrylate) that impart high crosslinking density can often make inks brittle and negatively affect adhesion. Furthermore, such acrylate monomers can also cause poor print performance.

[0011] To impart better lithographic properties to UV inks and reduce brittleness, rosin resins, which have been successfully used in conventional inks, can also be used in UV inks, provided that they exhibit sufficient solubility in acrylate, 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, the risk of polymerization during the ink or varnish production process is higher due to high temperatures or long dissolution times, and therefore the temperature is kept as low as possible while still remaining above the threshold for dissolving the rosin in acrylate.

[0013] While U.S. Patent No. 7,232,851 generally refers to electron beam and / or UV-curable lithographic ink compositions and printing methods that simply use rosin soluble in acrylate, 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 pentaacrylate and hexaacrylate, for example, dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate. As will be discussed in more detail below, solubility in these pentafunctional and hexafunctional acrylates is achieved without the use of high temperatures (i.e., temperatures above 135°C).

[0014] Another challenge 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 escape from the rapidly moving rollers due to the strong centrifugal force of the rapidly rotating rollers and the limited cohesive force of the ink, contaminating the printing press and resulting in frequent large-scale cleaning and production stoppages. Typical means of reducing misting are to increase the solid content of the ink by adding fillers or to increase the pigment content.

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

[0016] European Patent No. 3434711 mentions the use of rosin esters in energy-curable (EC) inks. It does not mention LEDs, aluminum additives, or 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 has a low tendency to show misting in an offset printing press while maintaining excellent press performance and LED drying characteristics. Although this may overlap with other descriptions, the various aspects of the present invention are shown below. However, the present invention is not limited to the following. [1] 25-85% of one or more acrylates, at least one of which is pentaacrylate or hexaacrylate; With 0-20% of one or more photoinitiators; With 5-60% of one or more rosin-modified polyester resins having a molecular weight of 5,000-35,000 Daltons; With 0.2-5% of one or more aluminum additives; With 0.1-5% of one or more polymerization stabilizers; 0-50% coloring agent and A printing ink or varnish composition containing [the specified substance]. [2] The composition according to [1], wherein the rosin-modified polyester resin has an acid value of 10 to 30 mg KOH / g. [3] The composition according to [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 [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 mg KOH / g, and a softening point of 85 to 110°C. [5] A composition according to any one of [1] to [4], comprising 5% or less of vegetable oil and / or mineral oil. [6] The composition according to any one of [1] to [5], wherein at least one acrylate is a pentaacrylate. [7] The composition according to [6], wherein the pentaacrylate is dipentaerythritol pentaacrylate. [8] The composition according to any one of [1] to [5], wherein at least one acrylate is a hexaacrylate. [9] The composition according to [8], wherein the hexaacrylate is dipentaerythritol hexaacrylate.

[10] A composition according to any one of [1] to [9] that can be cured by UV-LED irradiation.

[11] A composition according to any one of [1] to

[10] , comprising 0.5 to 20% of one or more photoinitiators.

[12] A composition according to any one of [1] to

[10] , comprising 0% photoinitiator (i.e., the composition is photoinitiator-free), and curable by electron beam irradiation.

[13] The composition according to

[12] , which is an offset printing ink or varnish.

[14] The composition according to any one of [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 [1] to

[14] , wherein the aluminum additive is selected from the group consisting of aluminum alkoxides, aluminum chelates, aluminum carboxylates, or blends thereof.

[16] The aforementioned aluminum additive (a) Aluminum monopropoxylate, aluminum dipropoxylate, or aluminum trippropoxylate; aluminum monoisopropoxylate, aluminum diisopropoxylate, or aluminum triisopropoxylate; aluminum monobutylate, aluminum dibutylate, or aluminum tripylate; aluminum alkoxides selected from the group consisting of aluminum monoisobutylate, aluminum diisobutylate, or aluminum triisobutylate, and blends thereof; (b) Aluminum mono-ethyl acetate tochelate with diisopropylate; aluminum dichelates and aluminum trichelates with alkyl acetate or alkyl diketone, and blends thereof, selected from the group; or (c) Aluminum carboxylate selected from the group consisting of aluminum triacetate or aluminum trippropionate, and blends thereof. The composition described in

[15] .

[17] The composition according to any one of [1] to

[16] , wherein the aluminum additive is aluminum diisopropoxide ethyl acetacetate.

[18] The composition according to any one of [1] to

[17] , wherein the aluminum additive is in an inert solvent, and the inert solvent is selected from mineral oil or vegetable oil.

[19] The composition according to

[18] , wherein the inert solvent is sunflower oil.

[20] The composition according to

[19] , wherein the aluminum additive is aluminum diisopropoxide ethyl acetacetate in sunflower oil.

[21] The rosin-modified polyester resin is (a) Sources 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; (b) A source selected from the group consisting of gumrosin, maleic anhydride, fumaric acid, glycerin, pentaerythritol and blends thereof; or (c) Sources selected from the group consisting of tetrahydrophthalic anhydride, glycerin, aromatic monofunctional acids, monofunctional alcohols, and blends thereof. A composition derived from any one of [1] to

[20] .

[22] The composition according to any one of [1] to

[21] , wherein the rosin-modified polyester resin 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 acid dianhydride, or methylcyclohexenedicarboxylic acid 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, tert-butylbenzoic acid, naphthoic acid, and linoleic acid.

[23] The composition according to

[22] , wherein the rosin-modified polyester resin is derived from i) gum rosin or tall oil rosin; ii) one or more bifunctional acids or anhydrides selected from cyclohexenedicarboxylic acid dianhydrides or methylcyclohexenedicarboxylic acid dianhydrides; 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, tert-butylbenzoic acid, naphthoic acid and linoleic acid.

[24] The composition according to

[22] or

[23] , wherein the rosin-modified polyester resin is derived from i) gum rosin or tall oil rosin; ii) one or more bifunctional acids or anhydrides selected from cyclohexenedicarboxylic acid dianhydrides or methylcyclohexenedicarboxylic acid dianhydrides; iii) one or more monofunctional, bifunctional, trifunctional or tetrafunctional polyols selected from glycerin or trimethylolpropane; and iv) benzoic acid.

[25] (a) The rosin-modified polyester resin has 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, A composition according to any one of [1] to

[24] .

[26] The composition according to any one of [1] to

[25] , wherein the rosin-modified polyester has an ethanol content of more than 4 g / 10 g, preferably 4 to 10 g / 10 g.

[27] An LED-curable offset ink or coating composition comprising any or more of the varnish compositions described in [1] to

[26] .

[28] The ink or coating composition according to

[27] , comprising 5-40% of one or more colorants.

[29] The ink or coating composition according to

[27] or

[28] , comprising 25-85% of any or more of the compositions described in [1] to

[26] .

[30] A composition according to any one of [1] to

[29] that shows an improvement of 5% or more in ink and press performance scores compared to a comparative example that does not contain aluminum additives, preferably showing an improvement of 10% or more in ink and press performance scores compared to a comparative example that does not contain aluminum additives, and more preferably showing an improvement of 15% or more in ink and press performance scores compared to a comparative example that does not contain aluminum additives.

[31] A printed article comprising any or more of the compositions described in [1] to

[30] .

[32] A method for preparing printed materials, Applying one or more of the compositions described in [1] to

[30] to a substrate by offset printing; The composition is cured by a UV-LED or an electron beam. A method that includes this.

[0018] No reference or specification of any document in this application constitutes an acknowledgment that it represents prior art relating to the present invention. [Brief explanation of the drawing]

[0019] [Figure 1] This is a spider diagram comparing the invention's ink (containing aluminum additive, outer curved shape) with a comparative ink (not containing aluminum additive, inner curved shape). In particular, the spider diagram shows the ink performance scores for Examples 2A-5A of the invention versus Comparative Examples 2B-5B. [Modes for carrying out the invention]

[0020] The present invention is further described by the following set of embodiments and combinations of embodiments arising, for example, from dependencies and backreferences as shown. In particular, in each example in which the scope of an embodiment is referred to, in the context of terms such as “any one of Embodiments 1 to 5,” all embodiments within this scope are intended to be expressly disclosed to those skilled in the art, i.e., the wording of this term should be understood by those skilled in the art as synonymous with “any one of Embodiments 1, 2, 3, 4 and 5.”

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

[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 is 25-85% of one or more acrylates, at least one of which is pentaacrylate or hexaacrylate; With 0-20% of one or more photoinitiators; With 5-60% of one or more rosin-modified polyester resins having a molecular weight of 5,000-35,000 Daltons; With 0.2-5% of one or more aluminum additives; 0.1-5% of one or more polymerization stabilizers and The present invention provides a varnish composition containing the following:

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

[0025] The ink is suitable for any substrate on which lithographic printing is performed, such as printing on graphic paper, wrapping paper, and packaging applications on carton board and foil.

[0026] Preferably, the LED-curable ink or varnish of the invention is made of the following materials: 25-85% of one or more acrylates, at least one of which is pentaacrylate or hexaacrylate; 0.5-20% photoinitiator and; A rosin-modified polyester resin having a molecular weight of 5,000 to 35,000 Daltons, comprising 5-60%; With 0.2-5% aluminum additive; 0.1-5% polymerization stabilizer and; 0-50% coloring agent and Includes.

[0027] Acrylate In one embodiment, a (meth)acrylic acid (i.e., (meth)acrylate) monomer suitable for use in the present invention includes an ester of acrylic acid or methacrylic acid having the defined structure.

[0028] A non-limiting list of examples of (meth)acrylate monomers suitable for use in the present invention includes n-octyl acrylate, iso-octyl 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, ethoxy This includes sylated 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 a mixture 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 may further contain an acrylate oligomer having a number average molecular weight of about 400 to 5,000 daltons and an acrylate functionality of 2 or more, such as epoxy acrylate, polyester acrylate, acrylic polyurethane, fatty acid modified polyester acrylate, or acrylic polyether, to impart rheological, pigment wetting, transfer, gloss, chemical resistance, and other film properties.

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

[0032] Preferably, the ink or varnish composition of the present invention comprises 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 comprises 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 hexaacrylate and at least one other acrylate selected from alkoxylated trimethylolpropane triacrylate, pentaerythritol tetraacrylate, alkoxylated pentaerythritol tetraacrylate, ditrimethylolpropane tetraacrylate, dipentaerythritol pentaacrylate, or mixtures thereof. More preferably, the ink or varnish composition of the present invention comprises 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 mixtures thereof.

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

[0035] Preferably, the ink or varnish of the present invention contains 25-60% pentaacrylate or hexaacrylate.

[0036] Photoinitiator The radiation-curable ink of the present invention contains a photoinitiator that absorbs in the UVA region of 320-400 nm, such as substituted benzophenones, aminoalkylphenones, acylphosphine oxides and thioxanthones, 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 mixtures thereof.

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

[0038] For inks designed for food packaging, it is advantageous to minimize the number of migrating low molecular weight monomer photoinitiators, or, more advantageously, to completely replace them with oligomer or polymer photoinitiators such as Omnipol TX, a trademark of IGM Resin.

[0039] Preferably, the ink or varnish composition according to the present invention comprises 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 Rosin resins, such as maleic acid-modified rosin esters or phenol-modified rosin resins, are widely used as printing ink vehicles in flexographic and gravure inks. Maleic acid-modified rosin esters often exhibit good pigment wetting, gloss retention, color retention, and adhesion, and typically show better solubility in acrylate than phenol-modified rosin esters. Rosin esters can be synthesized from trifunctional or tetrafunctional hydroxy compounds such as glycerin, trimethylolpropane, and pentaerythritol, as well as commercially available rosins such as Chinese gum rosin, wood rosin, or tall oil rosin, and difunctional acids such as maleic acid, fumaric acid, and itaconic acid. Rosin esters are commercially available and can be prepared as described in the "Printing Inks 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 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, although rosin esters are known in the art, the rosin resin for use in this application must be soluble not only in acrylates in general, but also in highly functional acrylates particularly suitable for use in LED inks, such as dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate. When used herein, the rosin resin has good solubility in the highly functional acrylate (particularly dipentaerythritol pentaacrylate or dipentaerythritol hexaacrylate) such that a 30% by weight (preferably 40% by weight, more preferably 50% by weight) solution of the rosin resin in the highly functional acrylate does not show visible precipitation at room temperature (i.e., 20°C). This can be achieved, for example, by the appropriate selection of acids such as maleic acid or maleic anhydride or cyclohexenedicarboxylic acid dianhydride or methylcyclohexenedicarboxylic acid dianhydride, which provide better solubility, and polyols such as glycerin and trimethylolpropane, as well as by limiting the molecular weight and softening point. To limit the molecular weight and provide excellent solubility in acrylate, monofunctional acids such as benzoic acid, methylbenzoic acid, tert-butylbenzoic acid, naphthoic acid, or fatty acids such as linoleic acid can be added to the reaction mixture to control the condensation reaction and 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 bifunctional acids or anhydrides; iii) one or more monofunctional, bifunctional, 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 acid dianhydride, or methylcyclohexenedicarboxylic acid dianhydride. More preferably, the difunctional acid or anhydride is selected from cyclohexenedicarboxylic acid dianhydride or methylcyclohexenedicarboxylic acid dianhydride.

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

[0045] Preferably, one or more monofunctional acids are selected from benzoic acid, methylbenzoic acid, tert-butylbenzoic acid, naphthoic acid, and linoleic acid. More preferably, one or more monofunctional acids are selected from benzoic acid, methylbenzoic acid, and tert-butylbenzoic acid. Even more preferably, 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 acid dianhydride, or methylcyclohexenedicarboxylic acid 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 acid dianhydrides or methylcyclohexenedicarboxylic acid dianhydrides; 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 acid dianhydrides or methylcyclohexenedicarboxylic acid dianhydrides; 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 several polar acid groups in addition to non-polar (hydrophobic) rosin units. Typically, a rosin resin with an acid value of 5 to 50 mg KOH / g (preferably 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 molten material settles from a standardized cup with a specified orifice under controlled test conditions in a furnace. This can be measured using automated equipment such as the DP70 from Mettler Toledo. The temperature range in which the ink or varnish of the invention can be produced is limited by the risk of polymerization of acrylate at higher temperatures. If the rosin ester has a higher softening point, for example, above 135°C, dissolving it in acrylate below 100°C is extremely difficult or takes a very long time. Unlike non-polymeric materials, polymers do not dissolve instantaneously; dissolution is controlled by the unraveling 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, the risk of polymerization during ink or varnish preparation increases due to high temperatures or long dissolution times. Preferably, the softening point of the rosin resin is in the range of 70 to 135°C or 85 to 110°C.

[0052] Before use, the rosin resin should be tested for suitability to ensure it has sufficient solubility to produce an ink or varnish. Typically, the solubility of the rosin resin should be such that a stable ink or varnish can be produced in dipentaerythritol pentaacrylate or dipentaerythritol hexaacrylate at concentrations greater than 30% by weight or greater than 40%. Stability indicates the absence of resin precipitation at lower storage temperatures and the absence of ink or varnish polymerization at higher storage temperatures.

[0053] Preferably, the ink or varnish composition of the present invention contains 5 to 50%, preferably 10 to 40%, of 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 below, preferably 100°C or below.

[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 5,000 to 35,000 or 5,000 to 30,000 daltons, as measured by size exclusion chromatography; a softening point of 70 to 135°C or 85 to 110°C; and an acid value of 5 to 50 mg KOH / g, 10 to 30 mg KOH / g, or 12 to 25 mg KOH / g. Preferably, the rosin resin has a molecular weight of 5,000 to 35,000 daltons, a softening point of 85 to 110°C, and an acid value of 10 to 30 mg KOH / g. More preferably, the rosin resin has a molecular weight of 5,000 to 35,000 daltons, a softening point of 85 to 110°C, and an acid value of 12 to 25 mg KOH / g.

[0057] The rosin resins used in this invention typically have an ethanol number greater than 4 g / 10 g. For example, the rosin resins used in this invention typically have an ethanol number of 4 to 10 g / 10 g. As is understood in the art, the ethanol number (EN) provides a measure of the resin's resistance to ethanol and, therefore, provides an indicator of the resin's polarity.

[0058] Aluminum additives Suitable aluminum additives for this application are aluminum alkoxides, aluminum chelates, or aluminum carboxylates. Suitable aluminum alkoxides include aluminum monopropoxylate, aluminum dipropoxylate or aluminum trippropoxylate, aluminum monoisopropoxylate, aluminum diisopropoxylate or aluminum triisopropoxylate, aluminum monobutylate, aluminum dibutylate or aluminum tripylate, aluminum monoisobutylate, aluminum diisobutylate or aluminum triisobutylate, or blends thereof. Suitable aluminum chelates include aluminum monoethyl acetate chelate with diisopropylate, aluminum dichelate and aluminum trichelate with alkyl acetate or alkyl diketone, or blends thereof. Suitable aluminum carboxylates include aluminum carboxylates selected from the group consisting of aluminum triacetate or aluminum trippropionate and blends thereof.

[0059] Preferably, the aluminum additive is an aluminum chelate. More preferably, the aluminum additive is selected from aluminum monoethyl acetacetate chelate with diisopropylate; aluminum dichelate and aluminum trichelate with alkyl acetacetate or alkyl diketone; and blends thereof.

[0060] Preferably, the aluminum additive is diisopropoxide ethyl acetacetate (CAS number 14782-75-3).

[0061] Most of these aluminum additives are commercially available. For better handling of moisture-sensitive additives (e.g., diisopropylate chelates, which can be called alkoxides), and to avoid hydrolytic degradation, aluminum additives can be pre-dissolved in small amounts in an inert solvent, such as sunflower oil. Thus, 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 ratio of the aluminum additive to the inert solvent is 1:1 by weight.

[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 the sunflower oil in a 1:1 weight ratio.

[0064] Preferably, the aluminum additive is an aluminum chelate in an inert solvent. More preferably, the aluminum additive is an aluminum monoethyl acetate to chelate with a diisopropylate in an inert solvent; an aluminum dichelate and aluminum trichelate with an alkyl acetate, an 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 monoethyl acetate to chelate with diisopropylate in sunflower oil; an aluminum dichelate and aluminum trichelate with alkyl acetate, alkyl diketone, or a blend thereof.

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

[0067] In this application, aluminum additives can react with hydroxyl groups, carboxyl groups, and amine groups in inks or varnishes during ink or varnish production at high temperatures of 80-120°C, which positively affects the rheology of the ink produced therefrom, particularly its structure or so-called body (viscosity at low shear rates, i.e., D=2 1 / s), and influences the cohesive force of the ink.

[0068] In the present invention, the aluminum additive is present in an amount of 0.2 to 5% of the ink or varnish composition. Preferably, the aluminum additive is present in an amount of 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% aluminum additive in an inert solvent such as sunflower oil. Preferably, the aluminum additive and the inert solvent are in a 1:1 weight ratio so that the composition contains 0.1 to 2.5% aluminum additive and 0.1 to 2.5% inert solvent.

[0070] Polymerization stabilizers (also called polymerization inhibitors in this specification) The ink of the present invention may further contain stabilizers to ensure a good shelf life. Examples of such polymerization inhibitors include nitroso-based stabilizers such as nitroso-phenylhydroxylamine; phenol-based stabilizers such as hydroquinone (HQ), methyl etherhydroquinone (MEHQ), butylhydroxytoluene (BHT), and 2,6-di-tert-butyl-N,N-dimethylamino-p-cresol; phenothiazine stabilizers and nitroso-phenylhydroxylamine stabilizers; and stabilizers based on copper thiocarbamates and zinc thiocarbamates. These components are useful as varnishes and inks and, due to long-wavelength absorbing photoinitiators suitable for LED drying, also absorb visible light, making them prone to immature 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 and heating to 80-120°C, then adding a solid rosin resin and other optional solid additives. Once the rosin resin has dissolved, the aluminum additive is added, the mixture is stirred at a predetermined temperature for a predetermined time, filtered, and then used to prepare an LED-curable ink. The varnish is characterized by its viscosity at high and low shear rates (D=50 1 / s and D=2 1 / s, respectively) as measured by a rheometer, and can be further characterized by vibration experiments to determine the storage modulus, loss modulus, and the ratio of storage modulus to loss modulus (tan delta), which represent the viscous and elastic portions of the varnish. A lower tan delta indicates a higher degree of reactivity with the aluminum additive. Typically, 0.5-5.0 wt% of the aluminum additive is added, depending on 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 present invention can be produced in a two-step process, for example, by preparing a premix and then grinding it. The premix is ​​prepared by placing the varnish and further monomers of the invention into a stirring kettle, starting the stirring, and then adding solid components such as colorants, fillers, and further additives. During mixing, the temperature is raised to 40-70°C and the temperature of the mixture is maintained until all the pigments are wet. The premix is ​​then transferred to a grinding process (e.g., a three-roll mill or a bead mill) and ground until the desired fineness of the grind is achieved, as measured by a grindmeter (e.g., an NPIRI gauge).

[0075] Coloring agents 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 include, 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, and Pigment Yellow. Low 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 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 2 38, 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, and their anatase or rutile metamorphoses can be selected from the group of titanium dioxide, zinc oxide, barium sulfate, zinc sulfide, lithopone, or calcium carbonate.

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

[0077] additives The LED-curable inks of the present invention may further contain additives typically used in the present invention to modify the flow, surface tension, gloss, 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 wax), shelf life stabilizers, and combinations thereof. These additives can function as leveling agents, shelf life stabilizers, wetting agents, slip agents, flowing 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 commercially available from Tego Chemie in Essen, Germany) and the Solsperse product line (Solsperse is a trademark and is commercially available from Lubrizol Company).

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

[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 of vegetable oil and / or mineral oil, and 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 unfunctionalized oils. That is, unless it is stated that the vegetable oil is functionalized (e.g., acrylic or epoxidized vegetable oil), the term "vegetable oil" refers to oil derived from fruit seeds or other parts that have not been functionalized (e.g., by chemical reaction) to include parts that can participate in polymerization processes. Similarly, the term "mineral oil" refers to petroleum hydrocarbon oils that have not been functionalized (e.g., by chemical reaction) to include parts that can participate in polymerization processes.

[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 of mineral oil, and even more preferably 1.5% by weight or less.

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

[0085] Typical values ​​for ink flow (inclined plate flow) are approximately 3-15 cm after 15 minutes, measured on an inclined aluminum plate using 1 cc of ink.

[0086] Preferably, the inks of the present invention exhibit a tack of 200 to 450 units, as measured using a "Tack-O-Scope" instrument (Model 2001) manufactured by IGT Testing Systems of the Netherlands, which is known to those skilled in the art. More preferably, the tack is approximately 230 to 350 units. Darker colors are typically adjusted to have a higher tack.

[0087] The radiation-curable ink of the present invention can be cured by LED light. The wavelength of the applied LED irradiation may be in the range of about 200 to 500 nm or about 320 to 400 nm. Preferably, the LED energy is about 30 to 1000 mJ / cm². 2 Within the range of approximately 50-500 mJ / cm² 2 The values ​​are within the range. The values ​​are measured using a calibrated radiometer with a good response in the relevant UVA region, such as the Powerpuck II from EIT. Furthermore, the LED source can be appropriately selected depending on the absorption spectrum of the radiation-curable composition. In addition, the ink of the present invention can be cured under inert conditions or as an ink laminated on 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. in Wilmington, Massachusetts, USA, or from Advanced Electron Beams Inc. (AEB) in Wilmington, Massachusetts, USA. The absorbed energy, also known as dose, is measured in 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. For the radiation-curable compositions of the present invention, a radiation dose of 20 to 30 kGy at oxygen levels of less than 200 ppm is usually sufficient to obtain a dried, solvent-resistant ink.

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

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

[0091] Test method molecular weight Typically, molecular weight can be measured by techniques known in the art, such as gel permeation chromatography. For example, molecular weight determination can be performed using THF as the mobile phase in a Hewlett-Packard 1050 series HPLC system equipped with two GPC Ultrastyragel columns of 103 Å and 104 Å (5 μm mixed, 300 mm × 19 mm, Waters Millipore Corporation, Milford, Massachusetts, USA). The molecular weight can be calculated by comparison with a polystyrene standard. Those skilled in the art will understand that this definition of molecular weight typically applies to polymer 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 that all sample material has dissolved. Add 3–5 drops of 1% alcoholic phenolphthalein solution. More indicator solution may be required for a colored solution. Titrate with standardized 0.1 N alcoholic potassium hydroxide (KOH) until the first pink color persists for 15 seconds. Record the volume of KOH solution used in ml. Calculation:

number

[0093] Softening point of rosin resin Mettler Droplet Softening Point (MDSP): The softening point can be measured using the Mettler Toledo DP70 automated softening point detector. Alternatively, the softening point can be determined by the Durand method: 3 grams of rosin resin are placed in a 17 x 50 mm test tube and heated to melt the resin. After the resin has cooled to room temperature, 50.0 g of mercury is added to the tube, and a thermometer is inserted into the mercury. The tube is heated in the bath at a rate of approximately 2°C / min. The temperature (°C) at which the resin first appears above the surface of the mercury is defined as the softening point.

[0094] Number of ethanol Unless otherwise specified, the amount of ethanol can be measured by weighing 10 g of the test resin into an Erlenmeyer flask. The resin is then dissolved in 50 g of toluene at a 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. The Erlenmeyer flask is placed on a piece of white paper with writing on it. Ethanol is then added dropwise to the Erlenmeyer flask at room temperature, stirring until the solution becomes cloudy and the writing on the paper is no longer visible. Once the writing is no longer visible, the titration is stopped, and the Erlenmeyer flask is weighed again to obtain "Weight 2" in grams. The amount of ethanol is then calculated by subtracting "Weight 1" from "Weight 2" and cited as g / 10g (i.e., grams of ethanol per 10 grams of resin).

[0095] Ink grind fineness Ensure the grind gauge (25 μm / 0~10 NIPRI) is clean and dust-free, and wipe it with a solvent-soaked cloth before starting the test. Apply the paint to both channels at the 25 μm mark. Ensure the color sample does not contain any skin or larger particles. The grind gauge block should be placed on a flat, non-slip surface underground. Place the doctor blade vertically on the grind gauge block with both hands, perpendicular to the grind gauge block. Then slowly pull the paint down to the end of the grind gauge. The blade must be pressed against the grind gauge so that the ink on both sides is removed almost completely. Record the μm reading of the grind gauge when at least four scratches made by larger ink particles appear.

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

[0097] tack Tack is measured using a calibrated "Tack-O-Scope" instrument (Model 2001) manufactured by IGT Testing Systems of the Netherlands. 1 ml of ink is placed on an EPDM rubber dispensing roller at 30°C and dispensed at a roller speed of 50 rpm for 90 seconds, then at 300 rpm for 30 seconds. The tack value is then obtained at a roller speed of 150 rpm.

[0098] Ink flow The flow is measured using a vertically positioned aluminum plate with 1 ml of ink placed on top. After 15 minutes, the distance (cm) the ink has flowed down the plate is recorded.

[0099] Press performance and verification of the invention's ink To further demonstrate the press performance and printing performance of the inventive ink compared to the comparative ink, two AMS LED dryers were used (output: 17W / cm² at wavelengths of 385-395nm). 2 The ink was printed using a ManRoland 700 four-color sheet offset UV printing press equipped with [specific equipment / features]. The printing test format (printing plate power source) is a multi-color design with various images to reflect the challenges that can occur in offset printing (e.g., high ink coverage, low ink coverage, gray shading, color intensity, sharp printing, etc.). The special images used are provided by FOGRA, a research institute 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, 130g / m² was used. 2 We selected Arto Magic Gloss graphic paper, which has a basis weight of [weight not specified].

[0100] Press performance is evaluated by the printer using a scoring system. A score of 100 represents excellent performance. The printer deducts points for each printing problem that occurs during printing. Finally, all remaining points are totaled to obtain the final score. The test includes LED drying performance, print quality, and performance during printing, which are detailed below.

[0101] The drying characteristics, solvent resistance, permanganate contamination, and ink transfer to the back of the page of LED inks will be tested and evaluated.

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

[0103] Potassium permanganate staining Place one drop of potassium permanganate aqueous solution (5%) onto 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 stain (density), the more uncured residual double bonds are present in the dried color. No staining means no points are deducted, while an optical density of 0.25 or more in the formed spot will result in a deduction of 25 points from 100.

[0104] Resistance to ink bleed-through After LED drying, place the counter paper on the printing surface and print at 10 tons / cm² on the printing press. 2Press the paper. Then remove the paper and inspect it for ink bleed-through on the counter paper. No ink bleed-through is considered good, and ink bleed-through exceeding 0.2 optical density is considered a poor result. If there is no ink bleed-through, no points are deducted. The worst score is for a bleed-through density exceeding 0.2, for which 20 points will be deducted per ink from 100. A more detailed bleed-through scoring is shown in Table 1. [Table 1]

[0105] We will evaluate the print quality, specifically its abrasion resistance and gloss.

[0106] Friction resistance The ink-printed material is placed in a Sutherland abrasion tester, and the surface is rubbed with counter paper for a specified period. The amount of ink rubbed off is visually inspected and scored from excellent to worst. The less ink damage and the less ink rubbed off, the higher the score. The results are evaluated on a scale from 0 (best) to 10 (worst). 0 or 1 means no deduction in the score, and 10 means -20 points per ink out of 100. A more detailed abrasion resistance scoring is shown in Table 2. [Table 2]

[0107] gloss Glossiness is measured at 60° using a BYK Micro Glossmeter. Higher glossiness indicates a better score. One gloss unit on the glossmeter is equivalent to one score. The average of all four process colors is recorded.

[0108] Ink performance during printing is evaluated based on ink duct flow, misting, and overall lithographic printing performance.

[0109] Duct flow 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 through the ink roller system may be slowed or interrupted. Ink duct flow is evaluated by a printer skilled in the art on a scale from 0 (best) to 5 (worst). The better the ink duct flow, the higher the score. For good flow from the ink duct, the score is not deducted from 100, and for worse flow, 22 points are deducted from 100 for each ink. A more detailed duct flow scoring is shown in Table 3. [Table 3]

[0110] Missing Misting can be a serious problem during a print job, as it contaminates the printing press and leads to frequent production stoppages for cleaning. Furthermore, small droplets of acrylate mist entering the air can also be harmful to health. While print settings and roller diameter can play a role, the chemical properties of the ink are considered a crucial factor. Misting is determined by placing a blank paper substrate close to the selected rollers, allowing ink mist originating from the rollers to accumulate on the paper over a specified time. The amount of ink on the paper is then determined by visually comparing the amount of ink mist on the paper or by measuring it with a densitometer. The less ink mist accumulated on the paper, the better the "misting" performance and the higher the score. Misting is rated from 0 (best) (meaning no score deduction) to 5 (worst) (100 to -20 points deduction per color). A more detailed misting scoring is shown in Table 4. [Table 4]

[0111] Lithographic printing performance Overall lithographic performance is evaluated based on key requirements and printing problems that can occur in a sheet offset printing press, such as ink / water balance, background staining, picking, staining by other colors, over-emulsification, ink in the dampening train, framing, and ink piling, as described below. These problems are known to those skilled in the art and are scored based on comparative scoring and procedures described later. Finally, the scores of the individual scoring results related to lithography are totaled to obtain the overall lithographic performance score. The individual requirements of lithographic performance are described below.

[0112] Ink / Water Balance The goal is to print offset ink with the minimum amount of dampening solution while the printing plate is still moving freely. The ink / water balance is also described by the term "water width," which is defined by the maximum possible range of ink and water settings during printing, under which the ink still flows steadily. The ink / water balance is rated by the printer on a scale of 0 to 5, where 0 (best) means no deductions and 5 (worst) means a deduction of 20 points per color from 100.

[0113] Soil stains Background smudges occur when the dampening solution fails to keep the non-image areas of the lithographic plate clean. Background smudges are rated by the printer on a scale of 0 to 5, with 0 (best) indicating no background smudges and no penalty, and 5 (worst) indicating a penalty of 20 points per color out of 100.

[0114] picking Picking refers to the process where ink pulls fibers away from the paper substrate or peels off the paper coating. Picking is rated by the printer on a scale of 0 to 5, with 0 (best) being no picking and no penalty, and 5 (worst) being a penalty of 20 points per color out of a total of 100.

[0115] Stain from another color Ink can become contaminated by other inks during printing tests, which can cause a shift in colorimetric analysis data, resulting in a detectable hue shift on the printed material. Contamination is rated by the printer on a scale of 0 to 5, where 0 (best) means no contamination and no point deduction, and 5 (worst) means a deduction of 20 points per color from 100.

[0116] Excessive emulsification If the ink absorbs too much water, it may create a furry ink coating that forms on the ink train roller. Excess emulsification is rated by the printer on a scale of 0 to 5, where 0 (best) means no excess emulsification and no penalty, and 5 (worst) means a penalty of 20 points per color out of 100.

[0117] Ink inside the dampening train Ink is detected visually in the dampening train and evaluated by the printer on a scale of 0 to 5, where 0 (best) means no ink in the dampening train and no points are deducted, and 5 (worst) means a deduction of 20 points per color out of 100.

[0118] Framing Framing refers to the visible presence of ink outside and around the area intended for printing. Framing is rated by the printer on a scale of 0 to 5, where 0 (best) means no framing and no penalty, and 5 (worst) means a penalty of 20 points per color out of 100.

[0119] Inkpiling Ink can accumulate in the roller, blanket, and plate areas, potentially leading to dried ink buildup. Piling is rated by the printer on a scale of 0 to 5, where 0 (best) means no piling and no penalty, and 5 (worst) means a penalty of 20 points per color out of 100.

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

[0121] The spider diagram, as shown in Figure 1, illustrates the ink performance scores of Examples 2A-5A of the invention versus comparative examples. Actual scores are also shown as examples.

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

[0123] 1.25-85% of one or more types of acrylic; With 0-20% of one or more photoinitiators; 5-60% of one or more rosin-modified polyester resins; With 0.2-5% of one or more aluminum additives; With 0.1-5% of one or more polymerization stabilizers; 0-50% coloring agent and A printing ink or varnish composition containing [the specified substance].

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

[0125] 3. The composition according to paragraph 1 or 2, comprising 0.5-20% 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 described in the paragraph, which is an offset printing ink or varnish.

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

[0129] 7. The composition according to any of the 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 monopropoxylate, aluminum dipropoxylate or aluminum trippropoxylate; aluminum monoisopropoxylate, aluminum diisopropoxylate or aluminum triisopropoxylate; aluminum monobutylate, aluminum dibutylate or aluminum tripylate; aluminum monoisobutylate, aluminum diisobutylate or aluminum triisobutylate, 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 monoethyl acetacetate to chelate with diisopropylate; aluminum dichelates and aluminum trichelates with alkyl acetacetate or alkyl diketone; 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 or aluminum trippropionic acid, 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 acetacetate.

[0134] 12. The composition according to any of the 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 acid, monofunctional alcohol, and blends thereof.

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

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

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

[0140] 18. An LED-curable offset ink or coating composition comprising one or more of the compositions described in paragraphs 1 to 17.

[0141] 19.1 The composition according to paragraph 18, comprising one or more colorants.

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

[0143] 21. A composition according to any of the paragraphs, which shows an improvement of 5% or more in ink and press performance scores compared to a comparative example that does not contain aluminum additives.

[0144] 22. A composition according to any of the paragraphs, which shows an improvement of 10% or more in ink and press performance scores compared to a comparative example that does not contain aluminum additives.

[0145] 23. A composition according to any of the paragraphs, which shows an improvement of 15% or more in ink and press performance scores compared to a comparative example that does not contain aluminum additives.

[0146] 24. A printed article comprising one or more compositions described in any one of paragraphs 1 to 23.

[0147] 25. A method for preparing printed materials, Applying one or more of the compositions described in paragraphs 1 to 23 to a substrate by offset printing; Curing the composition with a UV-LED or electron beam A method that includes this.

[0148] The present invention has been described in detail, including its various embodiments. However, those skilled in the art will understand that, considering this disclosure, modifications and / or improvements to the present invention can be made that fall within the scope and spirit of the invention. [Examples]

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

[0150] Rosin solubility Before preparing the varnish and ink compositions of the invention, the solubility of various rosin resins was determined. As can be seen from the data in Table 5 below, rosin resins with molecular weights of 50,000 daltons and 40,000 daltons are soluble in di-trimethylolpropanetetraacrylate (DiTMTPA), but not in dipentaerythritol hexaacrylate (DPHA). Rosin is soluble in dipentaerythritol hexaacrylate, which is a hexafunctional acrylate, only when its molecular weight is reduced. [Table 5]

[0151] The ink of the present invention and the comparative ink were produced in a two-step process by preparing a premix at 40-60°C as described, and then grinding it in a three-roll mill until a suitable pigment particle size (less than 10 μm for bulk particles) was achieved. After grinding was complete, the ink was ready for printing. The ink of the invention and the comparative ink exhibit a viscosity of 40-60 Pa·s, a tilt plate flow of 3-15 cm, and a tack of 230-330 units. [Table 6]

[0152] Comparative Example 1B varnish exhibits a viscosity of approximately 65 Pa·s and shows nearly Newtonian behavior, whereas the varnish of Example 1A of the Invention has a slightly higher viscosity of approximately 75 Pa·s and exhibits higher viscosity at low shear rates ("more structural"). [Table 7] [Table 8] [Table 9] [Table 10]

[0153] Table 11 shows a summary of the performance scores for 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 (particularly lithographic performance) of the inventive ink and reduces misting (higher scores) compared to the comparative ink. In the example, the aluminum additive is incorporated into the varnish, but it is understood that aluminum can be added directly to the ink itself just as easily.

[0155] For better visual understanding, individual results can be shown in a spider diagram. The spider diagram shows the ink performance scores for 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 aluminum additives (outer curved shape) covers more figure space than the comparative ink set (inner curved shape), which means that it is an ink that performs better with respect to misting, lithographic performance and ink drying, particularly as evaluated by solvent resistance and transfer-backside tests.

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

Claims

1. 25-85% of one or more acrylates, at least one of which is pentaacrylate or hexaacrylate; With 0-20% of one or more photoinitiators; With 5-60% of one or more rosin-modified polyester resins having a molecular weight of 5,000-35,000 Daltons; With 0.2-5% of one or more aluminum additives; With 0.1-5% of one or more polymerization stabilizers; 0-50% coloring agent and Includes, The rosin-modified polyester resin is derived from i) gum rosin, wood rosin, or tall oil rosin; ii) one or more bifunctional acids or anhydrides; iii) one or more bifunctional, trifunctional, or tetrafunctional polyols; and iv) one or more monofunctional acids. The aluminum additive is selected from the group consisting of aluminum alkoxides, aluminum chelates, aluminum carboxylates, or blends thereof. The aforementioned aluminum additive (a) Aluminum monopropoxylate, aluminum dipropoxylate, or aluminum trippropoxylate; aluminum monoisopropoxylate, aluminum diisopropoxylate, or aluminum triisopropoxylate; aluminum monobutylate, aluminum dibutylate, or aluminum tripylate; aluminum alkoxides selected from the group consisting of aluminum monoisobutylate, aluminum diisobutylate, or aluminum triisobutylate, and blends thereof; (b) Aluminum mono-ethyl acetate chelate with diisopropylate; aluminum dichelates and aluminum trichelates with alkyl acetate or alkyl diketone, and blends thereof, selected from the group; or (c) an aluminum carboxylate selected from the group consisting of aluminum triacetate or aluminum trippropionate, and blends thereof. Printing ink or varnish composition.

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

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

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

5. The composition according to claim 1, comprising 5% or less of vegetable oil and / or mineral oil.

6. The composition according to claim 1, wherein at least one of the acrylates is a pentaacrylate.

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

8. The composition according to claim 1, wherein at least one of the acrylates is a hexaacrylate.

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

10. The composition according to claim 1, which is curable by UV-LED irradiation.

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

12. The composition according to claim 1, comprising 0% photoinitiator (i.e., the composition is photoinitiator-free) and curable by electron beam irradiation.

13. The composition according to claim 1, which is an offset printing ink or varnish.

14. The composition according to claim 1, 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 claim 1, wherein the aluminum additive is aluminum diisopropoxide ethyl acetacetate.

16. The composition according to claim 1, wherein the aluminum additive is in an inert solvent, and the inert solvent is selected from mineral oil or vegetable oil.

17. The composition according to claim 16, wherein the inert solvent is sunflower oil.

18. The composition according to claim 17, wherein the aluminum additive is aluminum diisopropoxide ethyl acetacetate in sunflower oil.

19. The composition according to claim 1, wherein the rosin-modified polyester resin 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 acid dianhydride, or methylcyclohexenedicarboxylic acid dianhydride; iii) one or more bifunctional, trifunctional, or tetrafunctional polyols selected from glycerin or trimethylolpropane; and iv) one or more monofunctional acids selected from benzoic acid, methylbenzoic acid, tert-butylbenzoic acid, naphthoic acid, and linoleic acid.

20. The composition according to claim 19, wherein the rosin-modified polyester resin is derived from i) gum rosin or tall oil rosin; ii) one or more bifunctional acids or anhydrides selected from cyclohexenedicarboxylic acid dianhydrides or methylcyclohexenedicarboxylic acid dianhydrides; iii) one or more bifunctional, trifunctional or tetrafunctional polyols selected from glycerin or trimethylolpropane; and iv) one or more monofunctional acids selected from benzoic acid, methylbenzoic acid, tert-butylbenzoic acid, naphthoic acid and linoleic acid.

21. The composition according to claim 19, wherein the rosin-modified polyester resin is derived from i) gum rosin or tall oil rosin; ii) one or more bifunctional acids or anhydrides selected from cyclohexenedicarboxylic acid dianhydrides or methylcyclohexenedicarboxylic acid dianhydrides; iii) one or more bifunctional, trifunctional or tetrafunctional polyols selected from glycerin or trimethylolpropane; and iv) benzoic acid.

22. (a) The rosin-modified polyester resin has 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 claim 1.

23. The composition according to claim 1, wherein the rosin-modified polyester resin has an ethanol content of more than 4 g / 10 g.

24. An LED-curable offset ink or coating composition comprising the varnish composition described in claim 1, or the same.

25. The ink or coating composition according to claim 24, comprising 5 to 40% of one or more colorants.

26. The ink or coating composition according to claim 24, comprising 25 to 85% of the composition according to any one of claims 1 to 23.

27. The composition according to claim 1, which shows an improvement of 5% or more in ink and press performance scores compared to a comparative example that does not contain aluminum additives.

28. A printed article comprising the composition according to any one of claims 1 to 25 or claim 27.

29. A method for preparing printed materials, Applying the composition according to any one of claims 1 to 25 or 27 to a substrate by offset printing; The composition is cured by a UV-LED or an electron beam. A method that includes this.

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