JPH06263812A - Copolymerizable photoinitiator composition and photo-curable coating composition - Google Patents

Abstract

PURPOSE:To obtain a title photoinitiator composition which emits less odor during and after printing and a photo-curable coating composition which gives a cured film having high hardness and retaining good curability for a long time. CONSTITUTION:The photoinitiator composition is a product of the reaction of a polyol with benzoylbenzoic acid and an alpha,beta-unsaturated monobasic acid and has a mol.wt. of 300-2,000. The coating composition contains this phtoinitiator composition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copolymerizable photoinitiator composition which is cured by ultraviolet irradiation and a photocurable coating composition containing the same.

[0002]

2. Description of the Related Art In recent years, research on photocurable coating compositions, in particular, curable coating compositions by ultraviolet rays has been vigorously carried out. Among them, printing inks, overcoat varnishes, paints, adhesives, photoresists, etc. It is being put to practical use in the field. These are photoinitiators, resins (including both radically polymerizable resins and non-radically polymerizable resins), radically polymerizable monomers, pigments (not included in overcoat varnish), additives, etc. Consists of. A commonly used photoinitiator is benzophenone such as methyl o-benzoylbenzoate, Darocur 11
73, Darocur 2959, Irgacure 184, Irgacure 907 (Irgacure and Darocur are trademarks of Ciba-Geigy), and the like, Irgacure 6
Benzoin-based compounds such as 51, or thioxanthone-based compounds, EA
B (manufactured by Hodogaya Chemical Co., Ltd.), SEICOL PAA (manufactured by Seiko Chemical Co., Ltd.), Kayakyu EPA (manufactured by Nippon Kayaku Co., Ltd.) and other hydrogen donation systems are used. Since these photoinitiators do not have copolymerizability with the photocurable coating composition, they are not incorporated into the cured film and partially volatilize, causing printing, coating site or printed matter, odor of the coated matter, printed matter, etc. Causes deterioration of film physical properties such as decrease in film hardness.

A photocurable resin composition obtained by reacting a carboxyl group-containing benzophenone derivative with a polyol compound or the like is known for the purpose of improving these properties (Japanese Patent Publication No. 58-58).
-050612, Japanese Patent Publication No. 58-050613). However, the above technique generally has a large molecular weight because of the resin composition crosslinked with a polybasic acid,
As a result of the decrease in the reaction initiation efficiency of the initiator, the curability of the curable coating composition deteriorates. Furthermore, the one reacted with a long-chain fatty acid has a problem that the initiator acts as a plasticizer and the cured film strength is deteriorated. On the other hand, at present, the printing speed of a printing machine in the printing industry is high-speed printing of 80 to 150 m / min, so that the photocurable coating composition is actually required to have extremely fast curability.

[0004]

DISCLOSURE OF THE INVENTION The present invention provides a photocopolymerizable initiator composition and a photocurable coating composition for the purpose of preventing the deterioration of the odor, the cured film hardness, and the curability of the printed matter and the printed matter. It is provided.

[0005]

The present invention provides a copolymerizable photoinitiator composition having a molecular weight of 300 to 2000 obtained by reacting a divalent or higher valent polyol compound with benzoylbenzoic acid and an α, β unsaturated monobasic acid. It relates to a photocurable coating composition containing the same. Examples of the divalent or higher valent polyol compound used in the present invention include dihydric polyol compounds such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, butylene glycol and hexanediol, and trimethylolethane. Examples thereof include trivalent polyol compounds such as trimethylolpropane and glycerin, tetravalent polyol compounds such as pentaerythritol and ditrimethylolpropane, and hexavalent polyol compounds such as dipentaerythritol.

As benzoylbenzoic acid, o-benzoylbenzoic acid can be preferably used. Examples of the α, β-unsaturated monobasic acid include acrylic acid, methacrylic acid, itaconic acid, sorbic acid and crotonic acid, but acrylic acid is preferred from the viewpoint of curability and storage stability. In order to synthesize the copolymerizable photoinitiator of the present invention, first, a reactor equipped with a stirrer is charged with a polyol compound and benzoylbenzoic acid, and a reflux solvent such as toluene or xylene is optionally added under a nitrogen stream from 170 ° C. The temperature is gradually raised to 220 ° C. and the acid value is set to 10 or less. When the acid value is difficult to drop, the temperature may be raised to 260 ° C. The reaction ratio between the polyol compound and benzoylbenzoic acid is 1 to 5 mol of benzoylbenzoic acid with respect to the number of OH groups (2 to 6) of the polyol compound, and the reaction product leaves one or more OH groups. Then, the solvent is removed at about 200 ° C.
Furthermore, a reaction solvent such as methyl isobutyl ketone, methyl ethyl ketone, or cyclohexane was charged at 90 ° C., and hydroquinone was added under air or a mixed airflow of air / nitrogen = 1/1.
After adding a polymerization inhibitor such as metquinone, a reaction catalyst such as α, β-unsaturated monobasic acid and p-toluenesulfonic acid, sulfuric acid is charged and the temperature is gradually raised from 80 ° C (α, β unsaturated monobasic acid). It is preferable to add the acid dropwise), and at 115 ° C., when the acid value becomes 15 or less, preferably 10 or less, the desolvation mechanism works. If necessary, the solvent may be removed after washing with water.

The molecular weight of the initiator composition is 300-200.
0, preferably 300 to 1000 is preferable. When the molecular weight is higher than the above value, the reaction initiation efficiency of the initiator decreases,
The curability of the curable coating composition will decrease. The photoinitiator composition of the present invention has a Kayacure EP for improving curability.
It may be used in combination with a hydrogen-donor photoinitiator such as A, EAB, or Seicol PAA. The combination ratio is such that the photoinitiator composition of the present invention and the hydrogen donor system photoinitiator are 0.1 / weight ratio.
Used between 1 and 0.1. You may use together with another photoinitiator. The photoinitiator composition of the present invention is used by being contained in the photocurable coating composition in an amount of 1 to 20% by weight.

In the present invention, alkyd (meth) acrylate, polyester (meth) acrylate, epoxy (meth) acrylate, urethane (meth) acrylate and the like are used as the radically polymerizable resin of the curable coating composition. Further, resins having no radical-polymerizable property can be used, and these resins have a softening point of 3
There are resins having a temperature of 0 ° C. or higher, preferably resins having a softening point of 70 to 120 ° C., and more specifically, polyester, epoxy ester, urethane, diallyl phthalate resin and the like.
Examples of the radically polymerizable monomer include (hydrogenated) bisphenol (A or F) alkylene oxide adduct di (meth) acrylate, neopentyl glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, glycerin (alkylene oxide). ) Any other commercially available monomer such as tri (meth) acrylate, tetramethylolmethane tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, (alkyl) phenol or polyvalent phenol alkylene oxide adduct (meth) acrylate is used. Can also be used.

The composition ratio of the resin and the radical-polymerizable monomer is in the range of 0 to 60% by weight for the resin and 10 to 95% by weight for the radical-polymerizable monomer. When the curable coating composition is a printing ink, the incometer is used. The tack value is 5 to 1
5 poise / 25 ° C, 0.1-1 for overcoat varnish
It is appropriately blended so as to be 00 poise / 25 ° C. Further, when used as a printing ink, 5 to 40% by weight of pigments such as benzi yellow, lake red, phthalocyanine blue and carbon black are used. If necessary, additives such as anti-wear agents are used.

[0010]

EXAMPLES Examples will be shown below. In the examples, “part” means “part by weight” and “%” means “% by weight”. Example 1 [Synthesis of Copolymerizable Photoinitiator Composition] Polyol and o-benzoylbenzoic acid (a polybasic acid of phthalic anhydride in the case of Comparative Example) were placed in a four-necked flask equipped with a stirrer.
Xylene is charged and reacted under reflux at 170 ° C. under a nitrogen stream. Thereafter, the temperature is gradually raised and the solvent is removed at 220 ° C. when the acid value becomes 10 or less. Then, the mixture was cooled, and a mixed solvent of methyl isobutyl ketone / cyclohexane and hydroquinone were added at 80 ° C., and α, β monobasic acid in which p-toluenesulfonic acid was dissolved was added dropwise while blowing air. After completion of the dropping, the temperature is gradually raised and at 115 ° C., when the acid value becomes 20 or less, the desolvation mechanism is started.

A photoinitiator composition was synthesized in the same manner as in Example 1 with the formulations shown in Table 1.

[0012]

[Table 1]

Example 2 [Preparation of curable coating composition] Varnish: dipentaerythritol hexaacrylate 6
9.9% and hydroquinone 0.1% were charged, the temperature was raised to 100 ° C., and then 30 parts of DT150 (Toyo Kasei Co., Ltd. diallyl phthalate resin) was gradually charged and dissolved and then pumped out. The viscosity was 2100 poise (25 ° C). Printing ink is prepared by kneading each raw material. Since the overcoat varnish contains no pigment, it is produced by heating and melting at 50 to 100 ° C. Table 2 shows the ink formulations of Comparative Examples and Examples and the cured film performance thereof.

[0014]

[Table 2]

Yellow Pigment LIONOL YELLOW SGR-H Toyo Ink Mfg. Co., Ltd. Yellow Pigment Monomer 1 Dipentaerythritol Hexaacrylate Monomer 2 Pentaerythritol Tetraacrylate Kayakyua EPA Nippon Kayaku Co., Ltd. UV Initiator MOBB Methylorthobenzoylbenzoate Printing The ink performance was evaluated as follows. (1) Curability: In the case of printing ink in each curable coating, the ink (Comparative Examples 1B to 3B and Examples 1B to 5B) was 0.30 cc by RI tester (generally used in the printing ink industry. Use a simple printing machine to print 20 cm x 25 cm paper.
15 cc of ink is evenly printed), the overcoat varnish (Comparative Example 4B, Example 6B) is coated with a bar coater # 3, and UV irradiation (high pressure mercury lamp 120 W /
(3 cm3 light) When the material is dried by touch and cured, the larger the number at the conveyor speed (m / min) of the UV irradiation device, the better the curability. (2) Odor: Printed matter cured under the same conditions as curability was finely cut and placed in a glass bottle, and five panelists judged the odor relatively. (Poor) 1-5 (Good)
And (3) Pencil hardness: The pencil hardness of the printed matter cured under the same conditions as the curability.

[0016]

The photocurable coating composition of the present invention has an odor,
Good coating hardness. Further, it has a feature that the curing speed is higher than that of the conventional curable coating composition.

Continuation of front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location G03F 7/028 // C08G 59/68 NLE 8416-4J

Claims (2)

[Claims] 1. A copolymerizable photoinitiator composition having a molecular weight of 300 to 2000, which is obtained by reacting a divalent or higher valent polyol compound with benzoylbenzoic acid and an α, β unsaturated monobasic acid. 2. A photocurable coating composition comprising the copolymerizable photoinitiator composition according to claim 1.