JP7163844B2 - Rosin-modified polyester resin for active energy ray-curable lithographic printing ink, active energy ray-curable lithographic printing ink, and printed matter - Google Patents

Description

TECHNICAL FIELD The present invention relates to a rosin-modified polyester resin for active energy ray-curable lithographic printing ink, an active energy ray-curable lithographic printing ink, and printed matter.

Lithographic printing ink is ink with a relatively high viscosity of 5 to 100 Pa·s. In the lithographic printing press mechanism, ink is supplied from the ink reservoir of the printing press to the image area of the plate via multiple rollers, and in lithographic printing using dampening water, dampening water is supplied to the non-image area. As a result, in dampening water-less lithographic printing, the non-image area is made of a silicon layer and repels ink to form an image.

Particularly in lithographic printing using dampening water, the emulsification balance between the ink and the dampening water is important, and an ink with moderate emulsifying properties and suitability for high-speed printing is desired. If the emulsified amount of the ink is too high, the ink easily adheres to non-printing areas, causing stains. Ink transfer to paper and ink transfer to paper deteriorate, making it difficult to print stably.

Furthermore, in recent years, there has been an increasing demand for manpower saving, labor saving, automation, and speeding up in printing, and in particular, printing speed has been increasing more and more. In addition, there is a demand for an ink that can stably produce high-quality printed matter for a long time without trouble under various printing conditions, and ink manufacturers have made various improvements.

On the other hand, the active energy ray-curable ink contains, as a constituent component, an unsaturated compound having active energy ray-curable properties such as an acrylic ester compound. Forms a tough film by dimensional cross-linking. Since it cures instantly, post-processing can be performed immediately after printing, so it is suitable for packaging packaging printing and form printing in the commercial field, which require a strong film to improve productivity and protect designs, and active energy rays. A curable ink is preferably used.

Active energy ray-curable ink generally comprises a binder resin, an active energy ray-curable compound such as an acrylic ester compound, a pigment, a radical polymerization initiator, and various additives.

Furthermore, active energy ray-curable lithographic printing inks are required to have high curability due to demands for energy saving and high printing speed. In order to improve the curability, there are a method of using a radical polymerization initiator with high photosensitivity, a method of increasing the blending amount of the radical polymerization initiator, a method of using an active energy ray-curable compound with a large number of functional groups, and a binder resin. A method of imparting an active energy ray-curable functional group is effective, and a method of using a radical polymerization initiator with high photosensitivity and a method of increasing the blending amount of the radical polymerization initiator are particularly effective. However, on the other hand, since radical polymerization initiators are concerned about their effects on the human body, the types and amounts that can be used are being limited, making it difficult to develop high curability with radical polymerization initiators.

Adding an active energy ray-curable functional group to the binder resin is also effective for improving curability. It is difficult to impart an active energy ray-curable functional group to .

For these reasons, it is effective to use active energy ray-curable compounds with a large number of functional groups in order to improve curability, but in general, polyfunctional active energy ray-curable compounds have large molecular weights. High viscosity. Furthermore, the compatibility with the binder resin is often poor, and the viscosity of the mixture of the binder resin and the active energy ray-curable compound increases significantly, resulting in the problem of poor printability when used in ink. put away.

Dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, and the like are used as polyfunctional active energy ray-curable compounds for improving curability, but these also tend to cause a significant increase in viscosity as described above. Therefore, it is important to select the binder resin when using it.

Active energy ray-curable lithographic printing inks are required to have printability such as emulsification suitability and scumming resistance in addition to curability. In order to develop printability, it is effective to use a binder resin, and in order to achieve both printability and curability, unsaturated polyester resins, epoxy acrylate resins, urethane acrylate resins, polyester acrylate resins, and rosin-modified polyester resins are used. etc. have been considered. For example, Patent Document 1 discloses a resin obtained by modifying a saturated polyester with an isocyanate group-containing urethane acrylate. However, since these resins have a highly linear structure, it is difficult to obtain sufficient ink viscoelasticity, and they tend to impair printability such as misting property and scumming resistance. Patent Document 2 discloses a resin obtained by reacting a hydroxyl-excess polyester compound containing a rosin derivative polycarboxylic acid as an essential component with acrylic acid or methacrylic acid, but the rosin derivative polycarboxylic acid is sufficiently specified. On the contrary, when the amount of residual conjugated double bonds is large, curing inhibition tends to occur, and the problem of insufficient curability and printed film strength tends to occur. Patent Document 3 discloses a polyester resin containing a polyvalent carboxylic acid obtained by an addition reaction of a resin acid and an α,β-unsaturated carboxylic acid. However, since there is a limit to the amount that can be incorporated into the ink, deterioration of fluidity and gloss has been a problem.

JP-A-2001-348516 JP-A-2-51516 JP 2010-070742 A

SUMMARY OF THE INVENTION An object of the present invention is to provide an active energy ray-curable lithographic printing ink that achieves both printability and print film strength, and printed matter thereof.

As a result of intensive studies to solve the above problems, a rosin-modified polyester resin containing a specific alkylene glycol as a constituent component and having a specific n-hexane tolerance value is used as a binder resin for active energy ray-curable lithographic printing inks. By doing so, the compatibility with the polyfunctional active energy ray-curable compound is improved, and it is possible to achieve both the fluidity and the curability of the ink, leading to the completion of the present invention.

That is, the present invention provides an active energy ray-curing reaction product of at least a resin acid (A), an α,β-unsaturated carboxylic acid or its acid anhydride (B), and a polyalkylene glycol compound (C). A rosin-modified polyester resin for type lithographic printing ink,
The average molecular weight of the polyalkylene glycol-based compound (C) is 135 or more,
The present invention relates to a rosin-modified polyester resin for active energy ray-curable lithographic printing ink, characterized by having an n-hexane tolerance value of 2.00 or less.

The present invention also relates to the above active energy ray-curable rosin-modified polyester resin for lithographic printing ink, characterized by having a weight average molecular weight of 5,000 to 200,000.

The present invention also relates to the above active energy ray-curable rosin-modified polyester resin for lithographic printing ink, characterized by having an acid value of 5 to 90 mgKOH/g.

The present invention also relates to an active energy ray-curable lithographic printing ink containing the above rosin-modified polyester resin for active energy ray-curable lithographic printing ink and an active energy ray-curable compound.

The present invention also relates to the active energy ray-curable lithographic printing ink, characterized by containing dipentaerythritol pentaacrylate and/or dipentaerythritol hexaacrylate as the active energy ray-curable compound.

The present invention also relates to a printed material obtained by printing the active energy ray-curable lithographic printing ink on a substrate and curing it with an active energy ray.

The rosin-modified polyester resin for active energy ray-curable lithographic printing ink of the present invention has improved compatibility with dipentaerythritol hexaacrylate, making it possible to suppress an increase in ink viscosity. As a result, by using the rosin-modified polyester resin of the present invention, it was possible to provide an active energy ray-curable lithographic printing ink that achieves both printability and curability.

The rosin-modified polyester resin of the present invention comprises at least a resin acid (A), an α,β-unsaturated carboxylic acid or its acid anhydride (B), and a polyalkylene glycol compound (C) having an average molecular weight of 135 or more. Configured.

<Resin acid (A)>
The resin acid (A) used to obtain the rosin-modified polyester resin of the present invention is not particularly limited as long as it is an organic acid that exists as a free or ester contained in a natural resin. Examples include abietic acid, neoabietic acid, d-pimaric acid, iso-d-pimaric acid, podocarpic acid, agatenedicarboxylic acid, dammalolic acid, cinnamic acid, p-oxycinnamic acid, etc. A combination of types may be used. It is preferable to use these resin acids (A) in the form of natural resins in terms of handling, such as gum rosin, wood rosin, tall oil rosin, copal and dammar. Furthermore, some of them can be disproportionated, dimerized, or hydrogenated, but considering the reactivity with α, β-unsaturated carboxylic acids, conjugated double bond-containing compounds such as abietic acid It is desirable to contain 50% by mass or more.

<α,β-unsaturated carboxylic acid or acid anhydride thereof (B)>
Examples of α,β-unsaturated carboxylic acids or acid anhydrides thereof (B) used to obtain the rosin-modified polyester resin of the present invention include acrylic acid, methacrylic acid, maleic acid, fumaric acid, citraconic acid, and itaconic acid. Acids, crotonic acid, isocrotonic acid, cinnamic acid, 2,4-hexadienoic acid and the like, and acid anhydrides thereof may be mentioned, and may be used singly or in combination. In view of reactivity with the resin acid (A), maleic acid or its acid anhydride is preferred.

<Polyalkylene glycol-based compound (C)>
The polyalkylene glycol compound (C) used to obtain the rosin-modified polyester resin in the present invention has a structure represented by [-O-(C _m H _2m O) _n -] in the molecule (m and n are , each independently representing an integer of 2 or more.) and one or more hydroxyl groups, and is characterized by having an average molecular weight of 135 or more.
The average molecular weight of the polyalkylene glycol-based compound (C) is preferably 150 or more, more preferably 180 or more.
Furthermore, the average molecular weight of the polyalkylene glycol-based compound (C) is preferably 20,000 or less, more preferably 12,000 or less, and particularly preferably 5,000 or less.

When the average molecular weight is 135 or more, the intramolecular distance between the resin acids (A) with high pigment adsorption property taken into the resin is appropriately separated, and the wettability of the rosin-modified polyester resin to the pigment is improved. Fluidity and printability are improved. Furthermore, by incorporating the polyalkylene glycol-based compound (C) into the resin, it becomes possible to control the polarity of the rosin-modified polyester resin, and the compatibility with dipentaerythritol hexaacrylate is improved.

Here, the average molecular weight of the polyalkylene glycol-based compound (C) is a value calculated from the hydroxyl value according to the following formula.

Average molecular weight = (56.1 × average number of functional groups × 1000) / hydroxyl value

As the hydroxyl value (mgKOH/g), a value obtained by measuring by a method conforming to JIS K1557 is used.

Here, poly in the polyalkylene glycol-based compound (C) means that two or more alkylene glycol units are bonded, for example, a dialkylene glycol in which two alkylene glycol units are bonded, or three Both trialkylene glycol and tetraalkylene glycol having four bonds are polyalkylene glycol compounds, and the number of bonds is not particularly limited as long as the average molecular weight is 135 or more.
These alkylene glycol-based compounds (C) can be used singly or in combination, and derivatives, random polymers and block polymers of alkylene glycols can also be used.

More specific examples of the polyalkylene glycol-based compound (C) of the present invention include polyalkylene glycols such as polyethylene glycol, polypropylene glycol, and polybutylene glycol,
Polyethylene glycol monomethyl ether, polypropylene glycol monomethyl ether, polybutylene glycol monomethyl ether, polyethylene glycol monoethyl ether, polypropylene glycol monoethyl ether, polybutylene glycol monoethyl ether, polyethylene glycol monohexyl ether, polypropylene glycol monohexyl ether, polybutylene glycol monohexyl ether, polyethylene glycol monocyclohexyl ether, polypropylene glycol monocyclohexyl ether, polybutylene glycol monocyclohexyl ether, polyethylene glycol monooctyl ether, polypropylene glycol monooctyl ether, polybutylene glycol monooctyl ether, polyethylene glycol monodecyl ether, polypropylene glycol monodecyl ether, polybutylene glycol monodecyl ether, polyethylene glycol monododecyl ether, polypropylene glycol monododecyl ether, polybutylene glycol monododecyl ether, polyethylene glycol monononadecyl ether, polypropylene glycol monononadecyl ether, polybutylene glycol monononadecyl polyalkylene glycol monoalkyl ethers such as ethers,
Polyalkylene glycol monobenzyl ethers such as polyethylene glycol monobenzyl ether, polypropylene glycol monobenzyl ether, polybutylene glycol monobenzyl ether,
Examples include polyalkylene glycol polyethers such as polyethylene glycol glyceryl ether, polypropylene glycol glyceryl ether, polybutylene glycol glyceryl ether, polyethylene glycol sorbitol, polypropylene glycol sorbitol, and polybutylene glycol sorbitol.

The amount of the polyalkylene glycol-based compound (C) used in the present invention is not particularly limited, but from the viewpoint of printability, the polyalkylene glycol-based compound (C) should be 0.0% of the total amount of the components constituting the rosin-modified polyester resin. It is preferably 5 to 50% by mass. When it is 0.5% by mass or more, the compatibility with dipentaerythritol hexaacrylate is improved, and when it is 50% by mass or less, appropriate emulsifying suitability can be exhibited. Further, the amount of the polyalkylene glycol compound (C) is more preferably 1 to 30% by mass, particularly preferably 1.5 to 25% by mass, of the total amount of components constituting the rosin-modified polyester resin. .

Furthermore, in order to obtain the rosin-modified polyester resin of the present invention, other components as described below may be used in combination. These components can be used for reaction control during synthesis and for adjustment of resin physical properties.

<Polyol (D)>
In order to obtain the rosin-modified polyester resin of the present invention, it is preferable to use a polyol (D) together. The polyol (D) of the present invention refers to a compound that has two or more hydroxyl groups in the molecule and is not included in the polyalkylene glycol-based compound (C) described above.
Examples of the polyol (D) include, but are not limited to, dihydric alcohols such as linear alkylene dihydric alcohols 1,2-ethanediol, 1,2-propanediol, 1,3-propanediol, 1 ,2-butanediol, 1,4-butanediol, 1,2-pentanediol, 1,5-pentanediol, 1,6-hexanediol, 1,2-hexanediol, 1,5-hexanediol, 2, 5-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,2-octanediol, 1,9-nonanediol, 1,2-decanediol, 1,10-decanediol, 1,12 -dodecanediol, 1,2-dodecanediol, 1,14-tetradecanediol, 1,2-tetradecanediol, 1,16-hexadecanediol, 1,2-hexadecanediol, etc.
Branched alkylene dihydric alcohols 2-methyl-2,4-pentanediol, 3-methyl-1,5-pentanediol, 2-methyl-2-propyl-1,3-propanediol, 2,4-dimethyl -2,4-pentanediol, 2,2-dimethyl-1,3-propanediol, 2,2,4-trimethyl-1,3-pentanediol, dimethyloloctane, 2-ethyl-1,3- hexanediol, 2,5-dimethyl-2,5-hexanediol, 2-methyl-1,8-octanediol, 2-butyl-2-ethyl-1,3-propanediol, 2,4-diethyl-1, 5-pentanediol and the like are
Cyclic alkylene dihydric alcohols 1,2-cyclohexanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, 1,2-cycloheptanediol, tricyclodecanedimethanol, hydrogenated bisphenol A, hydrogenated Bisphenol F, hydrogenated bisphenol S, hydrogenated catechol, hydrogenated resorcinol, hydrogenated hydroquinone and the like.
Diethylene glycol and dipropylene glycol, which are polyalkylene glycols having an average molecular weight of less than 135, also correspond to the polyol (D).

Trihydric or higher polyhydric alcohols include, for example, glycerin, trimethylolpropane, pentaerythritol, 1,2,6-hexanetriol, 3-methylpentane-1,3,5-triol, hydroxymethylhexanediol, and trimethylol. Linear, branched and cyclic polyhydric alcohols such as octane, diglycerin, ditrimethylolpropane, dipentaerythritol, sorbitol, inositol and tripentaerythritol. These polyols (D) can be used singly or in combination.

The amount of the polyol (D) to be used to obtain the rosin-modified polyester resin of the present invention is not particularly limited, but it is preferably 0 to 50% by mass based on the total amount of components constituting the rosin-modified polyester resin.

<Monbasic acid (E)>
In order to obtain the rosin-modified polyester resin of the present invention, it is also preferable to use a monobasic acid (E) in combination. The monobasic acid (E) of the present invention is not particularly limited as long as it is other than the resin acid (A) described above.
Monobasic acids (E) include, for example, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, undecylic acid, lauric acid, tridecylic acid, myristic acid, and pentadecylic acid. , palmitic acid, heptadecylic acid, stearic acid, nonadecanic acid, arachidic acid, saturated fatty acids such as behenic acid, isocrotonic acid, lindelic acid, thumeric acid, myristoleic acid, palmitoleic acid, undecyleic acid, oleic acid, elaidic acid, gadolein Unsaturated fatty acids such as acids, gondrenic acid, cetoleic acid, erucic acid, brassic acid, linoleic acid, linoleidic acid, linolenic acid, eleostearic acid, arachidonic acid, sardine acid, and nisinic acid, benzoic acid, methylbenzoic acid, Aromatic monobasic acids such as tert-butyl benzoic acid, naphthoic acid, orthobenzoyl benzoic acid, etc. can be mentioned, and they can be used singly or in combination.
From the viewpoint of fluidity, the monobasic acid (E) is preferably an aromatic monobasic acid such as benzoic acid, methylbenzoic acid, tertiarybutylbenzoic acid, naphthoic acid, and orthobenzoylbenzoic acid.

<Other polybasic acids or acid anhydrides thereof (F)>
In order to obtain the rosin-modified polyester resin of the present invention, other polybasic acid or its acid anhydride (F) may be used in combination. Other polybasic acids or their acid anhydrides (F) include, for example, oxalic acid, malonic acid, succinic acid, glutaric acid, pimelic acid, sebacic acid, azelaic acid, dodecenylsuccinic acid, pentadecenylsuccinic acid, and the like. alkenyl succinic acid, maleic acid, 1,2,3,6-tetrahydrophthalic acid, 3-methyl-1,2,3,6-tetrahydrophthalic acid, 4-methyl-1,2,3,6-tetrahydrophthalic acid , hexahydrophthalic acid, 3-methylhexahydrophthalic acid, 4-methylhexahydrophthalic acid, hymic acid, 3-methylhimic acid, 4-methylhimic acid, and anhydrides thereof. Furthermore, fatty acids of natural fats and oils, such as tung oil fatty acid, linseed oil fatty acid, soybean oil fatty acid, coconut oil fatty acid, (dehydrated) castor oil fatty acid, palm oil fatty acid, safflower oil fatty acid, cottonseed oil fatty acid, rice bran oil fatty acid, olive oil fatty acid Dimer acids such as rapeseed oil fatty acids can also be used. These can be used singly or in combination.

The n-hexane tolerance value of the rosin-modified polyester resin of the present invention is preferably 2.00 or less. The n-hexane tolerance value is an index for comparing resin polarities. A higher n-hexane tolerance value indicates a more hydrophobic resin, and a lower n-hexane tolerance value indicates a more hydrophilic resin. When the n-hexane tolerance value is 2.00 or less, the compatibility with dipentaerythritol pentaacrylate and/or dipentaerythritol hexaacrylate is good. The n-hexane tolerance value of the rosin-modified polyester resin of the present invention is preferably 0.50-2.00, more preferably 0.70-1.90. When the n-hexane tolerance value is 0.5 or more, over-emulsification is sufficiently suppressed, and printability is particularly good.

A method for measuring the n-hexane tolerance value will be described. First, a stirrer chip is placed in an Erlenmeyer flask, and about 3 g of resin and tetrahydrofuran in an amount twice the mass of the resin (6.00 g of tetrahydrofuran for 3.00 g of resin) are added. Next, the resin is dissolved in tetrahydrofuran by stirring with a stirrer to obtain a resin solution. After that, while stirring the obtained resin solution, n-hexane is added dropwise until the resin solution becomes cloudy. The n-hexane tolerance value is calculated according to the following formula from the mass of the dropped n-hexane.

n-hexane tolerance value = dropwise n-hexane mass (g) ÷ resin mass (g)

For example, if 3.60 g of n-hexane is added to 3.00 g of resin, the n-hexane tolerance value is 1.20. If the mass of tetrahydrofuran to be dissolved is not twice the mass of the resin, the n-hexane tolerance value will change significantly. Within this range, even if the mass of tetrahydrofuran fluctuates, there is no effect on the n-hexane tolerance value.

The method for obtaining the rosin-modified polyester resin of the present invention is not particularly limited, and it can be obtained by a general synthesis method. As a method for obtaining the rosin-modified polyester resin of the present invention, for example, first, a resin acid (A) is reacted with an α,β-unsaturated carboxylic acid or its acid anhydride (B), and then a polyalkylene glycol compound ( It can be obtained by reacting with C). The reaction between the resin acid (A) and the α,β-unsaturated carboxylic acid or its acid anhydride (B) consists of a conjugated double bond in the resin acid and a double bond in the α,β-unsaturated carboxylic acid. It is a Diels-Alder addition reaction with a bond, and the subsequent reaction with a polyalkylene glycol compound (C) is an esterification reaction between a carboxyl group and a hydroxyl group. The aforementioned polyol (D), monobasic acid (E), other polybasic acids or their acid anhydrides (F) can also be incorporated into the rosin-modified polyester resin by an esterification reaction.
Either the Diels-Alder addition reaction or the esterification reaction may be carried out first, and the reactions may proceed at the same time. Also, the order in which each component is added may be freely selected.

Since the addition reaction product of the resin acid (A) and α, β-unsaturated carboxylic acid or its acid anhydride (B) becomes a polyvalent carboxylic acid compound, esterification with the polyalkylene glycol compound (C) Polymerization becomes possible by reaction. In addition, the conjugated double bond in the resin acid, which acts as a hardening inhibitor when irradiated with active energy rays, disappears through an addition reaction, and the introduction of a polycyclic structure derived from the resin acid improves printability such as emulsification properties, high-speed printability, and curability. and film strength.

Conditions for the Diels-Alder reaction are not particularly limited and can be carried out according to a conventional method. The reaction temperature is preferably in the range of 80°C to 200°C, but can be determined in consideration of the boiling point and reactivity of the compound used. It may be carried out in the presence of a polymerization inhibitor, examples of which include hydroquinone, p-methoxyphenol, methylhydroquinone, methoxyhydroquinone, 2,6-di-t-butylphenol, 2,6-di-t-butyl-4- Hydroxytoluene, t-butylcatechol, 4-methoxy-1-naphthol, phenothiazine and the like.

Conditions for the esterification reaction are not particularly limited and can be carried out according to a conventional method. The reaction temperature is preferably in the range of 180°C to 300°C, but can be determined in consideration of the boiling point and reactivity of the compound used. Moreover, it is possible to use a catalyst as needed. Catalysts include organic sulfonic acids such as benzenesulfonic acid, p-toluenesulfonic acid, p-dodecylbenzenesulfonic acid, methanesulfonic acid and ethanesulfonic acid, mineral acids such as sulfuric acid and hydrochloric acid, trifluoromethylsulfuric acid and trifluoromethylacetic acid. etc. can be exemplified. Furthermore, metal complexes such as tetrabutyl zirconate and tetraisobutyl titanate, and metal salt catalysts such as magnesium oxide, magnesium hydroxide, magnesium acetate, calcium oxide, calcium hydroxide, calcium acetate, zinc oxide and zinc acetate can also be used. be. These catalysts are usually used in the range of 0.01 to 5% by mass based on the total resin composition. Hypophosphorous acid, triphenylphosphite, triphenylphosphate, triphenylphosphine and the like can be used together in order to suppress the coloring of the resin due to the use of the catalyst.

The above (A) to (C) and optionally (D) to (F) can be blended simultaneously or stepwise. For example, resin acid (A), α, β-unsaturated carboxylic acid or its acid anhydride (B), polyalkylene glycol compound (C), optionally polyol (D), monobasic acid (E), Other polybasic acids or their anhydrides (F) can be simultaneously blended and reacted, or resin acids (A) and α,β-unsaturated carboxylic acids or their acid anhydrides (B) are blended, reacted, then polyalkylene glycol-based compound (C), optionally polyol (D), monobasic acid (E), other polybasic acid or its acid anhydride (F) blended and reacted good too. When they are blended simultaneously, the reaction temperature may be adjusted so that the Diels-Alder addition reaction between the resin acid (A) and the α,β-unsaturated carboxylic acid or its acid anhydride (B) occurs first.

The amount of the α,β-unsaturated carboxylic acid or its acid anhydride (B) is preferably more than 15% by mass, more preferably 16 to 200% by mass, based on the total amount of the resin acid (A). . Within the above range, the curability and fluidity are excellent.

Furthermore, the monobasic acid (E) is preferably used in an amount of 1 to 50% by mass based on the total amount of components constituting the rosin-modified polyester resin. When it is 1% by mass or more, the risk of gelation during synthesis decreases, and when it is 50% by mass or less, it is easy to control the weight average molecular weight of the resin.

The rosin-modified polyester resin obtained by the above production method preferably has a polystyrene equivalent weight average molecular weight measured by gel permeation chromatography (GPC) of 5,000 to 200,000, more preferably 5,000 to 100, 000, more preferably 7,000 to 50,000. The acid value of the resin is preferably 5-90 mgKOH/g, more preferably 10-70 mgKOH/g. Moreover, the melting point of the resin is preferably 40° C. or higher. Within the above range, emulsification suitability, transferability, and curability when used as a printing ink are excellent.

<Active energy ray-curable lithographic printing ink>
The rosin-modified polyester resin of the present invention can be used to compose an active energy ray-curable lithographic printing ink.

The active energy ray-curable lithographic printing ink of the present invention contains the rosin-modified polyester resin of the present invention and an active energy ray-curable compound.

Furthermore, the active energy ray-curable lithographic printing ink of the present invention contains a pigment when used as a colored ink, but can be used as a clear ink or an overcoat varnish when no pigment is used. Therefore, the use of pigments is not limited.

The active energy ray-curable lithographic printing ink of the present invention contains 10 to 40% by mass of the rosin-modified polyester resin of the present invention, 30 to 75% by mass of the active energy ray-curable compound, and 0 to 40% by mass of a pigment. It is preferable to be Here, the rosin-modified polyester resin and the active energy ray-curable compound of the present invention may be prepared in advance in the form of varnish before use.

The active energy ray-curable compound in the present invention is a compound having an acrylic group in its molecule.

Specifically, monofunctional active energy ray-curable compounds such as 2-ethylhexyl acrylate, methoxydiethylene glycol acrylate, acryloylmorpholine,
Ethylene glycol diacrylate, polyethylene glycol diacrylate (n = 2-20), propylene glycol diacrylate, polypropylene glycol diacrylate (n = 2-20), alkylene (4-12 carbon atoms) glycol diacrylate, alkylene (carbon atoms 4-12) Glycol ethylene oxide adduct (2-20 mol) diacrylate, alkylene (4-12 carbon atoms) glycol propylene oxide adduct (2-20 mol) diacrylate, hydroxypivalyl hydroxypivalate diacrylate, tri Bifunctional activities such as cyclodecanedimethylol diacrylate, bisphenol A ethylene oxide adduct (2-20 mol) diacrylate, hydrogenated bisphenol A diacrylate, hydrogenated bisphenol A ethylene oxide adduct (2-20 mol) diacrylate, etc. energy ray curable compound,
Glycerin triacrylate, glycerin ethylene oxide adduct (3-30 mol) triacrylate, glycerin propylene oxide adduct (3-30 mol) triacrylate, trimethylolpropane triacrylate, trimethylolpropane ethylene oxide adduct (3-30 mol) ) trifunctional active energy ray-curable compounds such as triacrylates, trimethylolpropane propylene oxide adducts (3 to 30 mol) triacrylates,
Pentaerythritol tetraacrylate, pentaerythritol ethylene oxide adduct (4-40 mol) tetraacrylate, pentaerythritol propylene oxide adduct (4-40 mol) tetraacrylate, diglycerin tetraacrylate, ditrimethylolpropane tetraacrylate, ditrimethylolpropane ethylene tetrafunctional active energy ray-curable compounds such as oxide adduct (4 to 40 mol) tetraacrylate, ditrimethylolpropane propylene oxide adduct (4 to 40 mol) tetraacrylate,
Dipentaerythritol pentaacrylate, dipentaerythritol ethylene oxide adduct (5-50 mol) pentaacrylate, dipentaerythritol propylene oxide adduct (5-50 mol) pentaacrylate, dipentaerythritol hexaacrylate, dipentaerythritol ethylene oxide adduct product (6 to 60 mol) hexaacrylate, dipentaerythritol propylene oxide adduct (6 to 60 mol) polyfunctional active energy ray-curable compounds such as hexaacrylate,
and mixtures thereof.

The active energy ray-curable compound can be appropriately selected depending on the required physical properties of the cured film, and in addition to the compounds exemplified above, polyester acrylate, polyurethane acrylate, epoxy acrylate, etc. It is also possible to use an oligomer together.

From the viewpoint of curability, the active energy ray-curable compound preferably contains dipentaerythritol pentaacrylate and/or dipentaerythritol hexaacrylate.
The total content of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate is preferably 5 to 50% by mass, more preferably 10 to 45% by mass, in the total amount of the active energy ray-curable lithographic printing ink of the present invention. It is preferably contained in an amount of 15 to 40 mass %, more preferably.

When the rosin-modified polyester resin of the present invention and the active energy ray-curable compound are prepared in advance in the form of a varnish and used, the rosin-modified polyester resin of the present invention is added in an amount of 20 to 70% by mass, and the active energy ray-curable compound is used. It is preferable to adjust the type compound to contain 30 to 80% by mass. In addition to the above components, the varnish may further contain additives such as photopolymerization inhibitors, which will be described later. The varnish can be produced, for example, by mixing the above components under temperature conditions between room temperature and 160°C.

Pigments that can be used include inorganic pigments and organic pigments.
Examples of inorganic pigments include yellow lead, zinc yellow, Prussian blue, barium sulfate, cadmium red, titanium oxide, zinc white, red iron oxide, alumina white, calcium carbonate, ultramarine blue, carbon black, graphite, and aluminum powder.
Examples of organic pigments include soluble azo pigments such as β-naphthol, β-oxynaphthoic acid, β-oxynaphthoic allylide, acetoacetic allylide, pyrazolone, β-naphthol, β-oxynaphthoic acid Insoluble azo pigments such as arylide, allylide acetoacetate monoazo, allylide acetoacetate disazo, pyrazolone, copper phthalocyanine blue, halogenated (chlorinated or brominated) copper phthalocyanine blue, sulfonated copper phthalocyanine blue, metal-free phthalocyanine, etc. Phthalocyanine pigments, quinacridone pigments, dioxazine pigments, threne pigments (pyranthrone, anthanthrone, indanthrone, anthrapyrimidine, flavanthrone, thioindigo, anthraquinone, perinone, perylene, etc.), isoindolinone, metal complex, Various known and public pigments such as polycyclic pigments such as quinophthalone-based pigments and heterocyclic pigments can be used.

A photopolymerization initiator is preferably added to the active energy ray-curable lithographic printing ink of the present invention when ultraviolet rays are used. Photopolymerization initiators can be broadly classified into those that generate active species by cleaving bonds within molecules by light and those that generate active species by causing hydrogen abstraction reactions between molecules. In addition, when using an electron beam etc. as an active energy ray, a photoinitiator is unnecessary.

Examples of substances that generate active species by intramolecular bond cleavage by light include 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1, diethoxyacetophenone, 4-( 2-hydroxyethoxy)phenyl-(2-hydroxy-2-propyl)ketone, 2-methyl-2-morpholino(4-thiomethylphenyl)propan-1-one, 2-hydroxy-2-methyl-1-phenylpropane -1-one, 1-hydroxycyclohexylphenyl ketone, [4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propan-1-one, benzyldimethylketal, oligo{2-hydroxy- Acetophenones such as 2-methyl-1-[4-(1-methylvinyl)phenyl]propane}, 4-[(2-acryloyl)oxyethoxy]phenyl-2-hydroxy-2-propylketone, benzoin, benzoin isopropyl Ethers, benzoins such as benzoin isobutyl ether, mixtures of 1-hydroxycyclohexylphenyl ketone and benzophenone, (2,4,6-trimethylbenzoyl)diphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide and acylphosphine oxide, benzyl, methylphenylglyoxyester, and the like.

Examples of substances that generate active species by intermolecular hydrogen abstraction reactions include benzophenone, methyl o-benzoylbenzoate, 4-phenylbenzophenone, 4,4′-dichlorobenzophenone, hydroxybenzophenone, and 4-benzoyl-4. benzophenones such as '-methyl-diphenyl sulfide, acrylated benzophenone, 3,3',4,4'-tetra(t-butylperoxycarbonyl)benzophenone, 3,3'-dimethyl-4-methoxybenzophenone, 2- Thioxanthones such as isopropylthioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone and 2,4-dichlorothioxanthone; aminobenzophenones such as Michler's ketone and 4,4'-bisdiethylaminobenzophenone; 10-butyl-2- Chloroacridone, 2-ethylanthraquinone, 9,10-phenanthrenequinone, camphorquinone and the like.
One of these photopolymerization initiators may be used, or two or more of them may be used in combination, if necessary.

When the active energy ray-curable lithographic printing ink of the present invention is cured by irradiating it with ultraviolet rays, the ink can be cured only by adding a photopolymerization initiator. can also Examples of photosensitizers include triethanolamine, methyldiethanolamine, dimethylethanolamine, triisopropanolamine, methyl 4-dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate, and benzoic acid. Amines such as (2-dimethylamino)ethyl, (n-butoxy)ethyl 4-dimethylaminobenzoate, and 2-ethylhexyl 4-dimethylaminobenzoate.

When ultraviolet light is used as the active energy ray, the amount of the photopolymerization initiator is 0.01 to 15% by mass, preferably 0.05 to 10% by mass, in the printing ink. If the amount is less than 0.01% by mass, the curing reaction will not be sufficiently carried out, and if the amount exceeds 15% by mass, the thermal polymerization reaction will easily occur and the stability of the ink will be easily impaired, which is not preferable.

Moreover, a polymerization inhibitor can be added to the active energy ray-curable lithographic printing ink of the present invention.

Specific examples of photopolymerization inhibitors include (alkyl)phenol, hydroquinone, catechol, resorcinol, p-methoxyphenol, t-butylcatechol, t-butylhydroquinone, pyrogallol, 1,1-picrylhydrazyl, phenothiazine, p -benzoquinone, nitrosobenzene, 2,5-di-tert-butyl-p-benzoquinone, dithiobenzoyl disulfide, picric acid, cupferron, aluminum N-nitrosophenylhydroxylamine, tri-p-nitrophenylmethyl, N-(3- oxyanilino-1,3-dimethylbutylidene)aniline oxide, dibutyl cresol, cyclohexanone oxime cresol, guaiacol, o-isopropylphenol, butyraldoxime, methylethylketoxime, and cyclohexanone oxime. Although not particularly limited, one or more compounds selected from the group consisting of hydroquinone, p-methoxyphenol, t-butylhydroquinone, p-benzoquinone, and 2,5-di-tert-butyl-p-benzoquinone It is preferred to use
When adding a photopolymerization inhibitor, from the viewpoint of not inhibiting curability, the amount is preferably 3% by mass or less based on the total mass of the ink, and in the range of 0.01 to 1% by mass. It is even more preferred to use

Furthermore, the active energy ray-curable lithographic printing ink of the present invention may contain various additives such as anti-friction agents, anti-blocking agents, and slip agents.

The atmosphere for irradiating the active energy ray is preferably an atmosphere replaced with an inert gas such as nitrogen gas. Heat the active energy ray-curable composition layer with an infrared heater or the like before irradiating the active energy ray, or heat the active energy ray curable lithographic printing ink cured layer with an infrared heater or the like after irradiating the active energy ray. This is effective for finishing hardening quickly.

The active energy ray of the present invention refers to ultraviolet rays, electron beams, X-rays, α-rays, β-rays, γ-rays, microwaves, high-frequency waves, etc., but any energy species that can generate radical active species may be used. , visible light, infrared light, and laser light. Specifically, ultra-high pressure mercury lamps, high pressure mercury lamps, medium pressure mercury lamps, low pressure mercury lamps, metal halide lamps, xenon lamps, carbon arc lamps, helium/cadmium lasers, YAG lasers, excimer lasers, argon lasers, LEDs (light emitting diode), etc.

The active energy ray-curable lithographic printing ink of the present invention is prepared by mixing the above-described printing ink components at room temperature to 100°C with a kneader, a triple roll, an attritor, a sand mill, a gate mixer, or other kneading, mixing, and adjusting machine. Manufactured using When adding the rosin-modified polyester resin for producing ink, it may be added in the form of the rosin-modified polyester resin itself or in the form of a varnish.

The active energy ray-curable lithographic printing ink of the present invention is generally applied to lithographic offset printing using dampening water, but it is also suitably used for waterless lithographic printing that does not use dampening water. The active energy ray-curable lithographic printing ink of the present invention can be used for printed materials for forms, printed materials for various books, printed materials for packaging such as carton paper, various printed materials for plastics, printed materials for seals/labels, printed materials for art, printed materials for metal (art printed materials, Beverage can printed matter, food printed matter such as canned food, etc.). It may also be used as an overcoat varnish.

An example of the composition of the active energy ray-curable lithographic printing ink used in the present invention is as follows:
Resin 10-40% by mass
Active energy ray-curable compound 30 to 75% by mass
Pigment (organic pigment/inorganic pigment) 0-40% by mass
Photopolymerization initiator 0 to 15% by mass
Other components 1 to 15% by mass
is mentioned.

The base materials include uncoated paper such as woodfree paper, lightly coated paper, art paper, coated paper, lightweight coated paper, coated paper such as cast coated paper, white paperboard, paperboard such as ball coated paper, and synthetic paper. Examples include paper, aluminized paper, and plastic sheets such as polypropylene, polyethylene, polyethylene terephthalate, and polyvinyl chloride.

EXAMPLES Next, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples. In addition, "parts" in the present invention represent parts by mass, and "%" represents % by mass.

In the present invention, the weight average molecular weight was measured by Tosoh's gel permeation chromatography (HLC-8320). A calibration curve was prepared with standard polystyrene samples. Tetrahydrofuran was used as an eluent, and three columns of TSKgel Super HM-M (manufactured by Tosoh Corporation) were used. The measurement was performed at a flow rate of 0.6 ml/min, an injection volume of 10 µl, and a column temperature of 40°C.

In the present invention, the acid value was measured by the neutralization titration method. As a measuring method, 1 g of rosin-modified polyester resin was dissolved in 20 ml of tetrahydrofuran (THF). Thereafter, 3 ml of a 3% by mass phenolphthalein solution was added as an indicator, and neutralization titration was carried out with a 0.1 mol/l ethanolic potassium hydroxide solution. The unit is mgKOH/g.

In the present invention, the n-hexane tolerance value was measured by the following method. Specifically, a stirrer chip was placed in a 100 ml Erlenmeyer flask, 3.00 g of the obtained rosin-modified polyester resin and 6.00 g of tetrahydrofuran were added, and the resin solution was prepared by thoroughly stirring with a stirrer to dissolve the rosin-modified polyester resin in tetrahydrofuran. Obtained. Thereafter, n-hexane was added drop by drop while stirring was continued until the resin solution became cloudy (resin precipitated), and the n-hexane tolerance value was calculated according to the following formula from the mass of n-hexane added.

n-hexane tolerance value = dropwise n-hexane mass (g) ÷ resin mass (g)

In the present invention, the melting point of the resin was measured using a melting point measuring apparatus M-565 (manufactured by BUCHI). 10 mg of finely pulverized resin was densely packed in a capillary, and the temperature was raised from 25° C. to 150° C. at a rate of 2° C./min.

In the present invention, the progress of the Diels-Alder addition reaction was confirmed by gas chromatograph-mass spectrometry by the decrease in the detection peak of the α,β-unsaturated carboxylic acid or its acid anhydride (B).

A rosin-modified polyester resin and an active energy ray-curable lithographic printing ink composition were prepared according to the formulations shown below.

<Resin Synthesis Example for Examples> Synthesis of Resin A1 25 parts of gum rosin and 10 parts of maleic anhydride were charged in a stirrer, a reflux condenser with a water separator, and a four-necked flask with a thermometer, and the temperature was adjusted to 180 while blowing nitrogen gas. ℃ for 1 hour.
Then, 14.5 parts of benzoic acid, 0.5 parts of PEG#1000 (polyethylene glycol, average molecular weight: 1000, manufactured by NOF Corporation), 25 parts of glycerin, 25 parts of pentaerythritol, 0.5 parts of p-toluenesulfonic acid monohydrate. 03 parts were added, and dehydration condensation was carried out at 230°C for 14 hours to obtain Resin A1 having an acid value of 5 mgKOH/g, a polystyrene conversion weight average molecular weight (Mw) measured by GPC of 200,000, and a resin melting point of 90°C. The n-hexane tolerance value of Resin A1 was 2.00. Table 1 shows the results.

<Example of preparation of varnish for working examples> Preparation of varnish A1 40 parts of Resin A1 obtained in a four-necked flask equipped with a stirrer, a reflux condenser and a thermometer, 30 parts of dipentaerythritol pentaacrylate, and 29 parts of dipentaerythritol hexaacrylate. 8 parts and 0.2 parts of t-butylhydroquinone were mixed and heated and melted at 100° C. to obtain varnish A1.

<Evaluation of varnish fluidity>
The resulting varnish A1 was cooled to room temperature, and the viscosity was measured using a cone-plate sensor HAAKE RheoStress 6000 viscosity/viscoelasticity measuring device (manufactured by Thermo Fisher) according to the flow curve mode measurement method. From the viscosity at a shear rate of 100/s, the varnish fluidity was evaluated according to the following criteria.
○: Viscosity less than 600 Pa s △: Viscosity 600 Pa s or more, less than 900 Pa s ×: Viscosity 900 Pa s or more (or unmeasurable)
The available level is 0.
Table 2 shows the results.

<Example of Ink Preparation for Examples> Preparation of Ink A1 63 parts of the obtained varnish A1, 20 parts of Lionol Blue FG7330 (indigo pigment manufactured by Toyocolor Co., Ltd.), 13.9 parts of trimethylolpropane triacrylate, 4,4' - 1.5 parts of bis(diethylamino)benzophenone, 1.5 parts of 2-methyl-2-monophorino(4-thiomethylphenyl)propan-1-one, and 0.1 part of t-butylhydroquinone, at 40 ° C. The mixture was kneaded with a roll mill and adjusted with trimethylolpropane triacrylate so that the tack of the ink was 9-10 to obtain a lithographic printing ink A1.
The tack of the ink was measured with an incomometer manufactured by Toyo Seiki Co., Ltd. at a roll temperature of 30° C. and 400 rpm for 1 minute.

<Synthesis Example of Resins for Examples> Synthesis of Resins A2 to A13 Resins A2 to A13 were obtained with the composition shown in Table 1 in the same manner as for resin A1. Table 1 shows the results of acid value, Mw, melting point and n-hexane tolerance value.

<Example of Varnish Preparation for Working Examples> Preparation of Varnishes A2 to A16 Varnishes A2 to A16 were obtained with the composition shown in Table 2 in the same manner as in Varnish A1. Varnish fluidity results are shown in Table 2.

<Example of Ink Preparation for Examples> Preparation of Inks A2 to A16 Inks A2 to A16 having the formulation shown in Table 3 were obtained in the same manner as for Ink A1.

<Resin Synthesis Example for Comparative Example> Synthesis of Resin B1 25 parts of gum rosin and 7 parts of maleic anhydride were charged in a stirrer, a reflux condenser with a water separator, and a four-necked flask with a thermometer, and the mixture was stirred at 180°C while blowing nitrogen gas. ℃ for 1 hour.
Then, 40 parts of benzoic acid, 23 parts of pentaerythritol, and 0.1 part of p-toluenesulfonic acid monohydrate are added, and dehydration condensation is performed at 230° C. for 14 hours to give an acid value of 29 mgKOH/g, weight average in terms of polystyrene measured by GPC. A resin B1 having a molecular weight (Mw) of 23,000 and a resin melting point of 90° C. was obtained. Resin B1 had an n-hexane tolerance value of 2.20. Table 1 shows the results.

<Example of preparation of varnish for comparative example> Preparation of varnish B1 40 parts of Resin B1 obtained in a four-necked flask equipped with a stirrer, a reflux condenser and a thermometer, 10 parts of dipentaerythritol pentaacrylate, and 49 parts of dipentaerythritol hexaacrylate. 9 parts of t-butylhydroquinone and 0.1 part of t-butyl hydroquinone were mixed and heated and melted at 100° C. to obtain varnish B1. In addition, evaluation of varnish fluidity was performed in the same manner as for varnish A1. Table 2 shows the results.

<Example of Ink Preparation for Comparative Example> Preparation of Ink B1 63 parts of the obtained varnish B1, 20 parts of Lionol Blue FG7330 (an indigo pigment manufactured by Toyocolor Co., Ltd.), 13.9 parts of trimethylolpropane triacrylate, 4,4' - 1.5 parts of bis(diethylamino)benzophenone, 1.5 parts of 2-methyl-2-monophorino(4-thiomethylphenyl)propan-1-one, and 0.1 part of t-butylhydroquinone, at 40 ° C. The mixture was kneaded with a roll mill and adjusted with trimethylolpropane triacrylate so that the tack of the ink was 9 to 10 to obtain a lithographic printing ink B1.
The tack of the ink was measured with an incomometer manufactured by Toyo Seiki Co., Ltd. at a roll temperature of 30° C. and 400 rpm for 1 minute.

<Resin Synthesis Example for Comparative Example> Synthesis of Resins B2 to B6 Resins B2 to B6 were obtained with the composition shown in Table 1 in the same manner as for resin B1. Table 1 shows the results of acid value, Mw, melting point and n-hexane tolerance value.

<Example of Varnish Preparation for Comparative Example> Preparation of varnishes B2 to B6 Varnishes B2 to B6 were obtained with the composition shown in Table 2 in the same manner as in varnish B1. Varnish fluidity results are shown in Table 2.

<Example of Ink Preparation for Comparative Example> Preparation of Inks B2 to B6 Inks B2 to B6 having the formulation shown in Table 3 were obtained in the same manner as for Ink B1.

Varnish fluidity was good except for varnish B1, varnish B2 and varnish B6. It is believed that this is because the resins B1, B2, and B6 have inappropriate n-hexane tolerance values, resulting in poor compatibility between the resins and dipentaerythritol pentaacrylate and/or dipentaerythritol hexaacrylate. .

The lithographic printing inks obtained in Examples and Comparative Examples were evaluated for cured film physical properties and printability by the following methods.

<Stain resistance evaluation>
Planographic printing inks A1 to A16 and B1 to B6 were applied to 90 kg/ream of Mitsubishi Tokubishi art paper (manufactured by Mitsubishi Paper Mills) at 10,000 sheets/hour using Lithrone 226 (a sheet-fed printing machine manufactured by Komori Corporation). A printing test was performed on 20,000 sheets of each ink, and the state of solid inking and scumming on the printed matter were visually confirmed. The stain resistance was evaluated from the number of wasted sheets until the occurrence of scumming on printed matter at the start of printing. Evaluation criteria are shown below.
⊚: Less than 500 sheets of lost paper ◯: 1000 or more and less than 1500 sheets of wasted paper △: 1500 or more and less than 2000 of wasted paper ×: 2000 or more of wasted paper Usable level is ◯ or higher.
Tap water containing 1.5% Astromark III clear (manufactured by Toyo Ink Co., Ltd.) and 3% isopropyl alcohol was used as dampening water. Printing was done with a water dial value 2% higher than the lower width limit. Table 4 shows the results.

<Evaluation of physical properties of cured film>
Lithographic printing inks A1 to A16 and B1 to B6 were printed on Maricoat paper (coated cardboard manufactured by Hokuetsu Paper Co., Ltd.) using an RI tester (a simple color development device manufactured by Akira Seisakusho) at a coating amount of 1 g/m ² , An air-cooled metal halide lamp (manufactured by Toshiba Corporation) of 120 W/cm was used to irradiate ultraviolet rays at 60 m/min.

Curability, MEK resistance, abrasion resistance, and fluidity of printed materials after ultraviolet irradiation were evaluated. Each evaluation result is shown in Table 4.

The curability was evaluated by visual observation of the condition when the printed surface was rubbed with a cotton cloth, and evaluated on a 4-grade scale. Evaluation criteria are shown below. ◎: no change ○: some scratches were observed but no peeling was observed △: some (less than 50%) peeling was observed ×: some (50% or more) or all peeling The usable level seen is 0 or higher.

The MEK resistance was evaluated by visually observing the condition when the printed surface was rubbed 30 times with a cotton swab dipped in MEK and evaluated in 4 grades. Evaluation criteria are shown below.
◎: No change ○: Some dissolution was observed on the surface, but no peeling was observed △: Some (less than 50%) peeling was observed ×: Some (50% or more) or all The usable level at which peeling was observed is 0 or higher.

The abrasion resistance of the coating film is measured according to JIS-K5701-1, using a Gakushin type friction fastness tester (manufactured by Tester Sangyo Co., Ltd.), using high-quality paper as friction paper, and after 500 reciprocations with a load of 500 g, Changes in the friction surface were visually evaluated in four stages. Evaluation criteria are shown below.
◎: no change ○: some scratches were observed but no peeling was observed △: some (less than 50%) peeling was observed ×: some (50% or more) or all peeling The usable level seen is 0 or higher.

<Evaluation of liquidity>
Lithographic printing inks A1 to A16 and B1 to B6 were dripped on a slanted plate tilted at 60°, and the length of the ink flowed in 10 minutes was measured and evaluated on a 4-point scale. Evaluation criteria are shown below.
A: 30 mm or more ◯: 20 mm or more and 30 mm or less △: 10 mm or more and 20 mm or less ×: 10 mm or less Usable level is ◯ or more.

Examples 1 to 3, 7 to 10, and 12 to 16 showed particularly good antifouling properties. This is because the active energy ray-curable lithographic printing ink has a polarity suitable for printing because it is obtained from an appropriate amount of raw materials and uses a rosin-modified polyester resin with an appropriate n-hexane tolerance value. Conceivable.

As shown in Table 4, the curability was good except for Comparative Examples 3 and 4. However, in Comparative Example 3, α, β-unsaturated carboxylic acid or its acid anhydride (B) is not blended in the resin composition, and a Diels-Alder reaction skeleton with the resin acid (A) is not formed. Therefore, it is considered that a large amount of residual conjugated double bonds caused curing inhibition, resulting in poor curing. In Comparative Example 4, the resin acid (A) was not blended in the resin composition, and the rigidity of the resin was poor, and it is considered that poor curing occurred.

MEK resistance and abrasion resistance were particularly good in Examples 1 to 6 and 9 to 14, in which the molecular weight of the resin was large and the amount of dipentaerythritol pentaacrylate and/or dipentaerythritol hexaacrylate in the ink was large. It is considered that this is because the film strength is increased by increasing the molecular weight and by increasing the blending amount of dipentaerythritol pentaacrylate and/or dipentaerythritol hexaacrylate.

Fluidity was good except for Comparative Examples 1, 2 and 5, 6. In Comparative Examples 1, 2 and 6, the compatibility of the resin with dipentaerythritol pentaacrylate and/or dipentaerythritol hexaacrylate was poor due to the inappropriate n-hexane tolerance value of the resin, resulting in poor fluidity in varnishes and inks. is thought to have deteriorated. In Comparative Example 5, the n-hexane tolerance value of the resin was appropriate, so the fluidity of the varnish was good. considered to have deteriorated.

Claims (6)

An active energy ray-curable rosin for lithographic printing ink, which is a reaction product of at least a resin acid (A), an α,β-unsaturated carboxylic acid or its acid anhydride (B), and a polyalkylene glycol compound (C). A modified polyester resin,
The average molecular weight of the polyalkylene glycol-based compound (C) is 135 or more,
A rosin-modified polyester resin for active energy ray-curable lithographic printing ink, characterized by having an n-hexane tolerance value of 2.00 or less. 2. The active energy ray-curable rosin-modified polyester resin for lithographic printing ink according to claim 1, which has a weight average molecular weight of 5,000 to 200,000. 3. The rosin-modified polyester resin for active energy ray-curable lithographic printing ink according to claim 1, which has an acid value of 5 to 90 mgKOH/g. An active energy ray-curable lithographic printing ink comprising the rosin-modified polyester resin for an active energy ray-curable lithographic printing ink according to any one of claims 1 to 3 and an active energy ray-curable compound. 5. The active energy ray-curable lithographic printing ink according to claim 4, wherein the active energy ray-curable compound contains dipentaerythritol pentaacrylate and/or dipentaerythritol hexaacrylate. 6. A printed material obtained by printing the active energy ray-curable lithographic printing ink according to claim 4 or 5 on a substrate and curing it with an active energy ray.