JPS6234278B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an ultraviolet curable printing ink, and particularly to an ultraviolet curable printing ink that can be suitably used in planographic printing. In recent years, pollution prevention has been achieved through the use of solvent-free printing inks.
This type of ink is being actively developed with the aim of improving productivity through rapid curing or improving the physical properties of the cured film. Various types of ultraviolet curable printing inks have been proposed so far, but if we evaluate them overall from a practical level, especially with respect to the various properties required for lithographic printing inks, we find that they are still insufficient. It's hard to say. That is, although relatively many conventional inks are satisfactory in terms of ultraviolet curing speed, most of them have several serious problems as described below. (1) Since the vehicle component is relatively hydrophilic and easily emulsified with dampening water, scumming is likely to occur. (2) Because it has poor solubility in petroleum-based solvents, a special cleaning solution is required when cleaning the printing press after printing. (3) Due to poor wetting with pigments, printed matter lacks gloss and the appearance of the pot during printing is poor. (4) Due to the high polarity of the entire system, it swells the blankets and rubber rollers of printing presses. (5) If it comes into contact with the skin of workers, it will irritate the skin and cause inflammation. (6) The cured film is too hard and lacks adhesion and flexibility. Therefore, the object of the present invention is to provide not only high-speed ultraviolet curing properties but also moisture emulsification resistance, ease of cleaning, low swelling of blankets and rubber rolls, non-inflammatory properties on the skin, high gloss, and high film physical properties. An object of the present invention is to provide an ultraviolet curable printing ink having the following properties. As a result of intensive research, the present inventors have completed the present invention by discovering that the following characteristic ink can achieve the above object. That is, the present invention provides (a) general formula [In the formula, R ₁ is a hydrogen atom or a methyl group; R ₂ is a hydrogen atom or a hydrocarbon group having 1 to 5 carbon atoms; R ₃ is a hydrocarbon group having 5 to 20 carbon atoms (however, Excluding phenyl groups substituted with or unsubstituted alkyl groups of numbers 1 to 10); m is a positive number of 0.5 to 2, and n is 1 to
It is a positive number of 2.5, and m+n=3. ] An ultraviolet curable vehicle prepared by mixing an addition-polymerizable unsaturated compound represented by (b) a solid resin soluble in the (a) addition-polymerizable unsaturated compound, and (c) a photopolymerization initiator as a vehicle. This invention relates to an ultraviolet curable printing ink as a main component. (a) Addition polymerizable unsaturated compound represented by the above general formula is, for example, an esterification of three raw materials: (meth)acrylic acid, a trimethylol-type trihydric alcohol having 5 to 9 carbon atoms, and an aliphatic carboxylic acid. It can be obtained by reaction. By changing the reaction ratio of the above raw materials, it is possible to obtain mixtures in which m and n in the general formula are variously changed. That is, mixtures of the following (a) to (d) in various ratios are obtained.

【formula】

【formula】

【formula】

[Formula] The mixing ratio of (a) to (d) is determined based on factors such as ultraviolet curability, solubility in the solid resin described below, swelling property in blankets and rubber rollers, and solubility in petroleum-based solvents commonly used as cleaning solvents. It is important to keep various properties well-balanced, and the m and n values defined in the above general formula are the numerical ranges of a desirable average mixed composition determined by taking these properties into consideration. Examples of trihydric alcohols used as raw materials for producing the addition-polymerizable unsaturated compound (a) include trimethylolethane, trimethylolpropane,
Examples of fatty acids include caprylic acid, pelargonic acid, undecanoic acid, lauric acid, tridecanoic acid, coconut oil fatty acid, soybean oil fatty acid, linseed oil fatty acid, linoleic acid, stearic acid, linolenic acid, and parinaline. acid,
Examples include arachidonic acid. In the present invention, a solid resin is used dissolved in the above-mentioned addition-polymerizable unsaturated compound, and such a solid resin generally has a softening point of 70 to 160°C, preferably 100 to 150°C, which dissolves in petroleum solvents. C. solid resins can be used, such as cyclic ketone resins, petroleum resins, aromatic hydrocarbon/formaldehyde resins, natural resin-modified phenolic resins, acrylic resins, diallyl phthalate resins, and the like. The cyclic ketone resin is a resin obtained by converting a cyclic ketone compound such as cyclohexanone, methylcyclohexanone, or acetophenone into a resin with an aldehyde compound such as formaldehyde. Hiratsu 80, 110H, 111, and 222 resins as well as Halon 80, sold by Honshu Kagaku Co., Ltd.
110 resins can be mentioned. The petroleum resin may be aliphatic, alicyclic, or aromatic, and commercially available products include, for example, "Neopolymer" sold by Nippon Petrochemical Co., Ltd. and "Neopolymer" sold by Toyo Soda Co., Ltd. Petkor”,
"Hi-Resin" sold by Toho Oil Co., Ltd.
Examples include resins sold by Mitsui Petrochemicals Co., Ltd. under trademarks such as "Petrozin" and "Tatsuku Ace." Aromatic hydrocarbon/formaldehyde resins include benzene, toluene, xylene,
Aromatic hydrocarbons such as ethylbenzene, isopropylbenzene, duurene and formaldehyde,
It is a resin obtained by addition condensation using a strong acid such as sulfuric acid as a catalyst, and xylene resin is particularly well known as a commercially available product, such as Mitsubishi Gas Chemical.
"Nicanor" sold by Matsushita Electric Works, Ltd.
Examples include resins with trademarks such as "National Xylene" sold by Co., Ltd. As the natural resin-modified phenolic resin, all those commonly used in oil-based inks of conventional products can be used, and for example, a resin sold by Dainippon Ink Chemical Co., Ltd. under the trademark "Betsukasite" can be used. Next, as the photopolymerization initiator used in the present invention, any initiator can be used as long as it is photoexcited when irradiated with actinic rays and easily causes a photopolymerization reaction. Examples include O-benzoylbenzoic acid methyl ester, thioxanthone, P-dimethylaminobenzaldehyde, P-dimethylaminoacetophenone, P-dimethylaminobenzoic acid isoamyl ester, 2-
Acilloin and derivatives thereof such as chlorothioxanthone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, decyl bromide and α-methylbenzoin; carbonyls such as 2-ethylanthraquinone, cyclohexanone and 9-fluorenone, etc. Compounds; diketones such as benzyl and diacetyl;
Organic sulfides such as diphenyl monosulfide, diphenyl disulfide, decyl phenyl sulfide and tetramethylthiuram monosulfide; acetophenone, benzophenone, phenyl-2-thienyl ketone, p-dimethylaminobenzophenone and Phenones such as P.P'-tetramethyldiaminobenzophenone;
Sulfonyl halides such as P-toluenesulfonyl chloride, 1-naphthalenesulfonyl chloride, 2-naphthalenesulfonyl chloride, 1,3-benzenedisulfonyl chloride, 2,4-dinitrobenzenesulfonyl bromide and P-acetamidobenzenesulfonyl chloride; Halogenated hydrocarbons such as carbon chloride, carbon tetrabromide, hexabromoethane, iodoform and 1,1,2,2-tetrabromoethane, etc.; also eosin, thionin, fluorescein, riboflavin and 3,6-diaminoacridine Examples include dyes such as. Such photopolymerization initiators can be used alone or in combination of two or more. The ultraviolet curable vehicle of the present invention is prepared by mixing 75 to 40 parts by weight of the addition polymerizable unsaturated compound (a), 20 to 50 parts by weight of the solid resin (b), and 2 to 20 parts by weight of a photopolymerization initiator. If more than 75 parts by weight of the compound of the above general formula is used, that is, less than 20 parts by weight of the solid resin, the viscosity of the printing ink will be too low and the photocurability will deteriorate, making it impractical. Moreover, when less than 40 parts by weight of the solid resin is used, that is, more than 50 parts by weight, the consistency of the printing ink is so high that it is generally difficult to print at room temperature. If the photopolymerization initiator is used in a small amount outside the scope of the present invention, it is not practical because the UV curability of the printing ink will be insufficient, and even if the photopolymerization initiator is used in a large amount outside the scope of the present invention, there is no problem. However, it is not economical because the printing ink is extremely expensive. If necessary, a known high-boiling point polymerizable monomer can be added to the UV-curable vehicle of the present invention to improve the curability, film performance, etc. A suitable amount is 30% or less, preferably 10% or less, based on the weight of . In addition to the UV-curable vehicle and color pigment of the present invention, the UV-curable printing ink of the present invention may contain polymerization inhibitors, plasticizers, fillers, solvents, and other auxiliary agents as necessary. . Next, the present invention will be specifically explained using Examples and Comparative Examples. Parts in the examples represent parts by weight. Example 1 134 parts (1 mol) of trimethylolpropane, 144 parts (1 mol) of caprylic acid, 3 parts of para-toluenesulfonic acid and 50 parts of toluene were placed in a reaction vessel and heated at 150°C for 3 hours in a nitrogen gas atmosphere. Stir to perform esterification reaction, then add 150 parts (2.08 mol) of acrylic acid, 3 parts of hydroquinone, and toluene.
120 parts of the mixture was added, and the mixture was heated and stirred at 120° C. for 6 hours while blowing air to carry out an esterification reaction. After washing the reaction solution with weak alkaline water and then water, a small amount of hydroquinone was added, and low-boiling substances were distilled off to obtain a pale yellow and transparent addition-polymerizable unsaturated compound (A). Next, 55 parts of this addition polymerizable unsaturated compound (A),
45 parts of "Nicanol HP-120" (xylene resin manufactured by Mitsubishi Gas Chemical Co., Ltd.) and 0.5 parts of hydroquinone were placed in a reaction container, and heated and stirred at 110°C for 1 hour while blowing air to form a viscous vehicle ( I got 1). Next, the formulation shown in Table 1 using this vehicle was thoroughly kneaded using three rolls to produce an ink. Example 2 Addition polymerizable unsaturated compound (A) described in Example 1
55 parts of Neopolymer 120 (petroleum resin manufactured by Nippon Petrochemicals Co., Ltd.) and 0.5 parts of hydroquinone were placed in a reaction vessel, and heated and stirred at 110°C for 1 hour while blowing air to form a viscous vehicle (2) at room temperature. Obtained. Next, the formulation shown in Table 1 using this vehicle was thoroughly milled in a three-roll mill to produce an ink. Example 3 Addition polymerizable unsaturated compound (A) described in Example 1
55 parts, Betsukasite-1110 (Dainippon Ink Chemical Co., Ltd.)
45 parts of natural resin-modified phenolic resin) and 0.5 part of hydroquinone were placed in a reaction vessel and stirred at 120°C for 1 hour while blowing air to obtain a vehicle (3) that was viscous at room temperature. Next, the formulation shown in Table 1 using this vehicle was thoroughly milled in a three-roll mill to produce an ink. Example 4 134 parts (1 mol) of trimethylolpropane, 284 parts (1 mol) of stearic acid, 3 parts of para-toluenesulfonic acid and 50 parts of toluene were placed in a reaction vessel, and esterification was carried out at 150°C for 4 hours in a nitrogen gas atmosphere. Then, 150 parts (2.08 moles) of acrylic acid, 3 parts of hydroquinone and 120 parts of toluene were added, and the esterification reaction was carried out at 120° C. for 10 hours while blowing air. After washing the reaction solution with weakly alkaline water and then water, a small amount of hydroquinone was added and low-boiling substances were distilled off to obtain a pale yellow and transparent addition-polymerizable unsaturated compound (B). Next, 60 parts of this addition polymerizable unsaturated compound (B), 40 parts of Nicanol HP-120 and 0.5 parts of hydroquinone
Place the sample in a reaction container and heat to 110°C while blowing air.
After heating and stirring at ℃ for 1 hour, the vehicle becomes viscous at room temperature (4)
I got it. Next, the formulation shown in Table 1 using this vehicle was sufficiently milled using three rolls to produce an ink. Example 5 Addition polymerizable unsaturated compound (B) described in Example 4
60 parts of Betucasite-1110, 40 parts of hydroquinone, and 0.5 parts of hydroquinone were placed in a reaction vessel, and heated and stirred at 110° C. for 1 hour while blowing air to obtain a vehicle (5). Next, the formulation shown in Table 1 using this vehicle was sufficiently milled using three rolls to produce an ink. Comparative Example 1 134 parts (11 mol) of trimethylolpropane, 72 parts (0.5 mol) of caprylic acid, 3 parts of para-toluenesulfonic acid and 50 parts of toluene were placed in a reaction vessel, and ester was heated at 150°C for 3 hours in a nitrogen gas atmosphere. reaction, then add 190 parts (2.64 mol) of acrylic acid, 3 parts of hydroquinone and 120 parts of toluene,
The esterification reaction was carried out at 120° C. for 7 hours while blowing air. After washing the reaction solution with weakly alkaline water and then water, a small amount of hydroquinone was added, and low-boiling substances were distilled off to obtain a pale yellow transparent polymerizable unsaturated compound (C) with a small amount of fatty acid modification. 55 parts of this addition polymerizable unsaturated compound (C), Nicanol HP-120 45
A vehicle (6) was obtained in the same manner as in Example 4 by adding 0.5 parts of hydroquinone and 0.5 parts of hydroquinone to a reaction vessel. Using this vehicle, the formulation shown in Table 1 was thoroughly kneaded using three rolls to produce an ink. Comparative Example 2 134 parts (1 mol) of trimethylolpropane, 360 parts (2.5 mol) of caprylic acid, 3 parts of para-toluenesulfonic acid, and 75 parts of toluene were charged in a nitrogen atmosphere.
Esterification reaction was carried out at 150°C for 4 hours, and then 38 parts (0.53 mol) of acrylic acid and 3 parts of hydroquinone were added.
150 parts of toluene were added thereto, and an esterification reaction was carried out at 120°C for 5 hours while blowing air. After washing the reaction solution with weakly alkaline water and then water, a small amount of hydroquinone was added and low-boiling substances were distilled off to obtain an addition polymerizable unsaturated compound (D) with a large amount of fatty acid modification. 60 parts of this addition-polymerizable unsaturated compound, 40 parts of Nicanol HP-120 and 0.5 parts of hydroquinone were placed in a reaction vessel, and vehicle (7) was added in the same manner as in Example 4.
I got it. The formulations in Table 1 using this vehicle were
The ink was produced by thorough kneading using this roll. Comparative Example 3 As an example of a product that is currently in practical use, the formulation shown in Table 1 uses Deitzkurite UE-8200 (an epoxy acrylate resin manufactured by Dainippon Ink and Chemicals Co., Ltd.) as a vehicle and trimethylolpropane triacrylate as a diluent. The ink was prepared by thoroughly kneading the mixture using three rolls.

[Table] Using the inks in each of the examples above, printing was performed using Roland Fabric RF01 printing, and evaluation tests were conducted on the following items. (1) Emulsification resistance The emulsification state of the ink on the kneading roller and ink drawing roller was observed and evaluated. (2) After printing 2,000 plates and blanks continuously, stop the printing machine,
The remaining state of ink on the plate and blanket was evaluated by touch. (3) Ease of cleaning with oil After printing was completed, the ink remaining on the mixing roller was sprinkled with kerosene, run dry, and then scraped off with a doctor to evaluate the degree of ease of cleaning. (4) Curing properties After spreading the ink on aluminum foil paper using an RI tester manufactured by Mei Seisakusho to a film thickness of 3 μm, the ink was transferred to a 25 cm total length equipped with a focusing reflector and output.
Light is irradiated by placing the lamp 15 cm below a 2kW single-tube high-pressure mercury lamp on a variable-speed conveyor that runs in a direction perpendicular to the long axis of the lamp. It was evaluated. (5) Gloss The gloss of the ink film was measured by spreading the ink on art paper with the above RI tester to a film thickness of 3 μm and completely curing it with the above ultraviolet irradiation device.
Gloss meter (digital variable angle photometer manufactured by Suga Test Instruments Co., Ltd.)
Measurements were made using a reflection angle of 60 degrees. (6) Blanket Swelling Ink was applied onto a synthetic rubber blanket S-5300 manufactured by Kinyosha Co., Ltd., and after leaving it in a dark place for one day and night, the ink was removed and the degree of swelling of the blanket was observed and evaluated. Table 2 lists the test results for each of the above items. The columns for printability and oil cleaning properties in the same table are as follows:
They are displayed according to the criteria of excellent 5, excellent 4, good 3, slightly poor 2, and poor 1.

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Claims (1)

[Claims] 1 (a) General formula [In the formula, R ₁ is a hydrogen atom or a methyl group; R ₂ is a hydrogen atom or a hydrocarbon group having 1 to 5 carbon atoms; R ₃ is a hydrocarbon group having 5 to 20 carbon atoms (however, (excluding phenyl groups substituted with or unsubstituted with an alkyl group of 1 to 10); m is a positive number of 0.5 to 2, n is a positive number of 1 to 2.5, and m+n=3. ] An ultraviolet curable vehicle prepared by mixing an addition polymerizable unsaturated compound represented by (b) a solid resin soluble in this (a) addition polymerizable unsaturated compound, and (c) a photopolymerization initiator. Ultraviolet curable printing ink whose main component is a vehicle. 2 (b) The solid resin is one or more selected from the group consisting of cyclic ketone resins, petroleum resins, aromatic hydrocarbon/formaldehyde resins, natural resin-modified phenolic resins, acrylic resins, acrylic resins, and diallyl phthalate resins. The ultraviolet curable printing ink according to claim 1, which is a solid resin. 3. (b) The ultraviolet curable printing ink according to claim 1, wherein the solid resin has a softening point in the range of 70 to 160°C. 4 The ultraviolet curable vehicle contains (a) 40 to 75 parts by weight of an addition polymerizable unsaturated compound and (b) 20 to 50 parts by weight of a solid resin.
(c) The ultraviolet curable printing ink according to claim 1, which is a mixed composition containing 2 to 20 parts by weight of a photopolymerization initiator.