JPH0222370A - Ultraviolet-curing ink composition - Google Patents

Abstract

PURPOSE:To provide the subject composition containing a specific poly(meth) acrylic acid eater, a compound containing ethylenic unsaturated group and a photo-polymerization initiator, having high rate of curing, giving a coating film having high hardness and useful as a printing ink. CONSTITUTION:The objective composition contains (A) a poly(meth) acrylic acid ester of tripentaerythritol and/or tetrapentaerythritol [preferably 80-100% of the OH group in the erythritol is esterified with (meth)acrylic acid], (B) a compound containing ethylenic unsaturated group and other than the component A (preferably epoxidized soybean oil, acrylic acid ester of a fatty acid- modified alkyd resin, etc.) and (C) a photo-polymerization initiator (preferably 2,4-diethylthioxanthone, benzyldimethyl ketal, etc.).

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an ultraviolet curable ink composition that can be suitably used as a printing ink.

(Prior Art) In recent years, the development of ultraviolet curable printing inks has been actively promoted for the purpose of preventing pollution by making printing inks solvent-free, improving productivity by rapid curing, or improving the physical properties of cured films.

(Problem to be solved by the invention) Ultraviolet curable printing ink is rapidly cured by irradiation with ultraviolet rays, and by taking advantage of its characteristics,
As the amount used increases, there is an increasing demand for improved productivity, and there is a demand for ink compositions with faster curing speeds.

(Means for Solving the Problems) As a result of intensive research, the present inventors have discovered the use of poly(meth)acrylic acid esters of tripentaerythritol and/or tetrapentaerythritol in order to improve the above-mentioned problems. As a result, they discovered an ultraviolet curable ink composition that has a fast curing speed, excellent print film hardness, and on-press stability, and completed the present invention. That is, the present invention provides tripentaerythritol and/or tetrapentaerythritol poly(meth)acrylic ester (
A), an ethylenically unsaturated group-containing compound (B) other than poly(meth)acrylic acid ester (A), and a photopolymerization initiator (
The present invention relates to an ultraviolet curable ink composition characterized by containing C).

Poly(meth)acrylic ester used in the present invention (
A) is tripentaerythritol and/or tetrapentaerythritol and (meth)acrylic acid disulfuric acid or P-
Preferably 70 to 15 in the presence of an esterification catalyst such as 1-luenesulfonic acid and a polymerization inhibitor such as hydroquinone.
It can be obtained by reacting at a temperature of 0°C.

Particularly preferred poly(meth)acrylic acid ester (A)
Examples include polyacrylic acid esters of tripentaerythritol and tetrapentaerythritol.

In addition, 50 to 100% of the O T-1 group contained in tripentaerythritol and/or tetrapentaerythritol
Particularly preferred is one in which 80 to 100% is esterified with (meth)acrylic acid.

In the present invention, an ethylenically unsaturated group-containing compound (B) is used. Specific examples of the ethylenically unsaturated group-containing compound (B) include epoxy resins such as bisphenol A type and phenol novolac type, epoxy resins such as epoxidized soybean oil, epoxidized rosin, and epoxidized polybutadiene, and acrylic acid. Epoxy acrylate II, which is a reaction product of epoxy acrylate II, urethane modified products of the above epoxy acrylates, ethylenically unsaturated group-containing resins such as acrylic esters of fatty acid-modified Alkit resins, or bisphenol A tetraethylene glycol diacrylate, bisphenol F polyethylene glycol diacrylate, tricyclodecane dimethyloldiacrylate, trimethylolpropane tripropoxy triacrylate, ditrimethylolpropane tetraacrylate, trimethylolpropane polyethoxy triacrylate, hydroxypivalic acid neopentyl glycol diacrylate, dipentaerythritol penta(or Examples include ethylenically unsaturated monomers such as xa)acrylate. Preferred ethylenically unsaturated group-containing compounds include epoxidized soybean oil, epoxy acrylates and urethane modified products such as epoxidized rosin, acrylic acid esters of fatty acid-modified alkyd resins, bisphenol A tetraethylene glycol diacrylate, and trimethylolpropane triacrylate. Propoxy triacrylate and the like can be mentioned.

Next, as the photopolymerization initiator (C) used in the present invention, for example, 2,4-diethylthioxanthone, isopropylthioxanthone, 2-chlorothioxanthone, benzophenone, benzyl dimethyl ketal, 1-hydroxycyclohexylphenyl Ketone, 2,4.6-
Trimethylbenzoyldiphenoylsulfine oxide, P-dimethylaminoacetophenone, 2-hydroxy-2=methyl-1-phenylpropan-1-one, methyl 〇-benzoylbenzoate, 2-ethylanthraquinone, P-dimethylaminobenzaldehyde, P-dimethylaminobenzophenone, P-dimethylaminobenzoic acid isoamyl ester, P-dimethylbenzoic acid ethyl ester, 2-methyl-1-(4-(methylthio)phenyl l-2-morpholino-propan-1-one, etc.) Such photopolymerization initiators can be used alone or in combination of two or more. Preferred photopolymerization initiators (C) include, for example, 2,4-diethylthioxanthone, benzyl dimethyl ketal, 2- Methyl-1-1
4-(methylthio)phenyl'5-2-morpholino-
Propan-1-one, benzophenone, methyl O-benzoylbenzoate, P-dimethylaminobenzoic acid ethyl ester, P-dimethylaminobenzoic acid isoamyl ester, etc. (meth)acrylic acid ester (A),
Preferably 10 to 70 parts by weight, particularly preferably 20 to 5 parts by weight
0 parts by weight and the ethylenically unsaturated group-containing compound (B), preferably 20 to 80 parts by weight, particularly preferably 30 to 80 parts by weight.
70 parts by weight and a photopolymerization initiator (C), preferably 0.5 parts by weight.
It is preferable to form a mixture in a proportion of 25 parts by weight, particularly preferably 2 to 20 parts by weight.

The ultraviolet curable composition of the present invention may optionally contain solid non-reactive resins, such as diallyl phthalate resin (Daiso Tsubu, manufactured by Osaka Soda Co., Ltd.), cyclic ketone resin (Hilac 80, manufactured by Hitachi Chemical Co., Ltd.). .110'), natural resin-modified phenolic resin, acrylic resin, etc. can be added to improve the performance of the cured film, but the amount added is 30% to the ultraviolet curable ink composition of the present invention.
The following are appropriate. The ultraviolet curable ink composition of the present invention is useful as a printing ink, but is also useful as a gloss coating for paper, a protective coating, a solder resist, and the like. In addition to the coloring pigment, the ultraviolet curable ink composition of the present invention may contain a polymerization inhibitor, a softening agent, a filler, a solvent, and other auxiliary agents, if necessary.

The ultraviolet curable ink composition of the present invention can be used in planographic printing (offset printing), letterpress printing, intaglio printing, screen printing,
It is printed on paper, plastic, metal, etc. by means such as sheet-fed printing, and then cured by irradiation with ultraviolet rays by a conventional method.

(Example) Next, the present invention will be specifically explained using Examples and Comparative Examples. Parts in Examples 0 represent parts by weight.

[Synthesis example of poly(meth)acrylic acid ester (A)]

Synthesis Example 1 100 parts of tripentaerythritol, 171 parts of acrylic acid
1 part, 2.0 parts of hydroquinone, 3.6 parts of sulfuric acid, and 300 parts of toluene were charged and heated, and the produced water was distilled together with the solvent and condensed. When 40 parts of water was produced in a separator, it was cooled to 0 reaction temperature. The reaction mixture, which was at 110-120°C, was dissolved in 1000 parts of toluene, neutralized with 20% NaOH aqueous solution, and then washed three times with 300 parts of 20% NaCl aqueous solution. The solvent was distilled off under reduced pressure to obtain 182 parts of liquid. This material has the following properties.

Viscosity (25℃) 19700 CPS acid value (m
gKOH/g) 0.03 Refractive index (25°C) 1.4913 Synthesis example 2 Mixture containing 57.3% tripentaerythritol and 25.6% tetrapentaerythritol (hydroxyl group content 3
3.6%) 100 parts, acrylic acid 171 parts, hydroquinone 2.0 parts, P-)luenesulfone 1120 parts, and toluene 300 parts were charged and heated. The produced water was distilled together with the solvent, condensed, and separated into water using a separator. It was cooled when 35.6 parts of was produced. The reaction temperature was 110-120°C. The reaction mixture was dissolved in 1000 parts of toluene and 20% NaOH
After neutralizing with an aqueous solution, it is washed three times with 300 parts of a 20% NaCl aqueous solution. The solvent was distilled off under reduced pressure to obtain 161 parts of a liquid. This material has the following properties.

Viscosity (25℃) 26500 CPS acid value (m
gKOH/g) 0.02 Refractive index (25°C> 1.4920 (Synthesis example of ethylenically unsaturated group-containing compound (B)) Synthesis example 3 Epoxidized soybean oil (manufactured by Adeka Argus Chemical Co., Ltd., 8DK CIZER0-130P, 246.7 parts of oxirane oxygen content 6.9%), 53.3 parts of acrylic acid, 1.1 parts of benzyltrimethylammonium chloride as an esterification catalyst, and 0.15 parts of methoxyphenol as a polymerization inhibitor. , the reaction temperature was 90°C and the acid value was 3.0.
The reaction was continued until below. The acid value of the reactant is 2
．． 1 (gKOH/g), viscosity is 16800CPS
(30°C), the appearance was a brown transparent liquid resin 0 Then, the above epoxidized soybean oil acrylic ester 30
70 parts by adding 14 parts of isophorone diisocyanate.
The reaction was carried out at ~80°C to obtain a modified boxylated soybean oil acrylic ester urethane.

Example 1 35 parts of polyacrylic ester obtained in Synthesis Example 1, 30 parts of epoxidized soybean oil acrylic ester urethane modified product obtained in Synthesis Example 3, bisphenol A tetraethylene glycol diacrylate (manufactured by Nippon Kashu Co., Ltd.) ,KAYARA
D PM-300) Part 5, Pridol.

20 parts of methyl 0-benzoylbenzoate (manufactured by Toyo Ink Co., Ltd., pigment), 10 parts of methyl 0-benzoylbenzoate (Daito Chemical Industry Co., Ltd. type, Daitocure OB, photopolymerization initiator), and 3 bottles of 0.1 part of methoxyphenol. The mixture was kneaded with a roll to obtain an ultraviolet curable ink composition A.

Example 2 30 parts of the polyacrylic ester obtained in Synthesis Example 2, 30 parts of the epoxidized soybean oil acrylic ester urethane modified product obtained in Synthesis Example 3, 10 parts of trimethylolpropane tripropoxytriacrylate, 20 parts of Bright Trend, and 0
-10 parts of methyl benzoyl benzoate and 0.1 part of methoxyphenol were kneaded using three rolls to obtain an ultraviolet curable ink composition B.

Comparative Example 1 In Example 2, polyacrylic acid ester 3 obtained in Synthesis Example 2
Ultraviolet curable ink composition C was obtained in the same manner as in Example 2, except that 0 part was changed to 30 parts of trimethylolpropane tripropoxy triacrylate.

[Ink performance evaluation method]

Curing type (curing time): 0.6 g of ink was tested using an Rr tester ((
After spreading the color onto carton paper using a 8011/cts metal halide lamp from a distance of 80°, the color was pressed onto art paper using an R1 tester, and the time required until the ink no longer adhered was applied. The irradiation time (seconds) is determined as the curing time.

Gloss of ring ink and emulsified ink: The gloss of the cured printed matter obtained above (original ink gloss) is evaluated by visual observation. In addition, after emulsifying 0.6 g of ink and dampening water using an R1 tester and draining the water, the color was spread on carton paper and cured under the same conditions as when measuring the gloss of the original ink. The gloss is similarly observed with the naked eye and evaluated according to the following criteria.

◎: Very good (The printed surface is smooth and very glossy.) Q: Good (The printed surface is glossy.) △: Between O and ×: Poor (The printed surface is not glossy.) , does not reflect even when exposed to light) Film hardness: In Example 1.2 and Comparative Example 1, 20 parts of Brightrend and 10 parts of methyl O-benzoylbenzoate were mixed with benzyl dimethyl ketal (manufactured by Ciba Geigy Co., Ltd., Irga). Cure 651) The same composition was prepared except that 3 parts were used, and the composition was coated on a hard PVC board using a bar coater to a film thickness of 10 μm, and hardened by irradiating ultraviolet rays under the following curing conditions.

80W/cm X 1 lamp, irradiation distance 8, irradiation time 1.
After 0 seconds, pencil hardness was measured based on JIS-5400.

Ultraviolet curable ink composition A B C Curing time (seconds) 0.2 0.2 0.8
Original ink gloss ◎ ◎ ○Emulsified ink gloss ◎ ◎ O Pencil hardness 5H5H
H [Effects of the Invention] The ultraviolet curable ink composition of the present invention has a fast curing speed and a high film hardness, and is suitable for printing ink.

Claims (1)

[Claims] Poly(meth)acrylic acid ester (A) of tripentaerythritol and/or tetrapentaerythritol, an ethylenically unsaturated group-containing compound (B) other than the poly(meth)acrylic acid ester (A), and a photopolymerization initiator (C) ) An ultraviolet curable ink composition comprising: