JPH07126312A - Photoinitiator composition and coating composition - Google Patents

Abstract

PURPOSE:To obtain a photocopolymerizable initiator composition which is less odorous during and after printing and enables rapid cure to give a cured film having high hardness by using two specific compounds in combination. CONSTITUTION:This photoinitiator composition comprises 10-90wt.% either a compound represented by the formula CH2=CR1CO(C2H4O)nO-phi-CO-C(CH3)2OR2 (wherein R1 is H or methyl; R2 is H or CH2=CR1CO; phi is a p-phenylene group; and (n) is an integer of 1-5) or a polymer thereof and 90-10wt.% 2-methyl-l [4-(methylthio)phenyl]-2-morpholinopropanone-1. Incorporation of 1-10wt.% 4,4'-bis(di-lower-alkylamino)benzophenone into the composition enhances curability. This composition is added to a compound having a radical-polymerizable double bond, in an amount of 0.1-20wt.% based on the compound, to produce the objective coating composition.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to photoinitiator compositions and coating compositions that cure upon exposure to ultraviolet light.

[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.), etc. 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.

For the purpose of improving these, for example, a copolymerizable photoinitiator obtained by subjecting 4 (2hydroxyethoxy) -phenyl-2hydroxy-2-propylketone (Darocur 2959 etc.) to an esterification reaction with acrylic acid chloride is known. (Japanese Patent Laid-Open No. 62-81345). However, when these copolymerizable photoinitiators are used alone in the photocurable coating composition, the curability is not necessarily good. On the other hand, the printing speed of the printing press in the printing industry is currently 80m to 150m.
Since the printing is performed at a high speed of m / min, the photocurable coating composition is required to have an extremely fast curability under the present circumstances.

[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]

That is, the present invention is
(A) 10 to 90% by weight of a compound represented by the general formula (1) or a polymer of the compound CH ₂ = CR ₁ CO (C ₂ H ₄ O) _n O-φ-CO-C (CH ₃ ) _2- OR ₂
(1) (In the formula, R ₁ is H or a methyl group, R ₂ is H or CH ₂ ═CR ₁ CO group, φ is a paraphenylene group, and n is an integer of 1 to 5.) and (b) 2 -Methyl-1
[4- (methylthio) phenyl] -2 morpholinopropanone-1, 90 to 10% by weight of a photoinitiator composition. The present invention further relates to a photoinitiator composition further comprising (c) 4,4'-bis (dilower alkylamino) benzophenone in an amount of 1 to 10% by weight.

The present invention further relates to a coating composition comprising a photoinitiator composition in an amount of 0.1 to 20% by weight based on the radical-polymerizable double bond-containing compound.

The compound represented by the general formula (1) is 4
-(2-Acryloyloxyethoxy) -phenyl 2-
Hydroxy-2-propylketone (ZLI-Merck)
3331), 4- (2-methacryloyloxyethoxy) -phenyl 2-hydroxy-2 propyl ketone, 4
-Acryloyloxyphenyl 2-acryloyloxy-2 propyl ketone and 4-methacryloyloxyphenyl 2-methacryloyloxy-2-propyl ketone. Further, as the polymer of the compound represented by the general formula (I), those obtained by polymerizing 4- (2-methacryloyloxyethoxy) -phenyl 2-hydroxy-2propylketone, for example, Esacure manufactured by Fratelli Lamberty Co., Ltd. There is KIP.

In the initiator composition of the present invention, the component (b) 2-
Methyl-1 [4- (methylthio) pheni] -2morpholinopropanone-1 is Irgacure 90 from Ciba-Geigy.
Available as 7. . 4,4'-bis (di-lower alkylamino) of component (c) in the initiator composition of the present invention
Specific examples of benzophenone include 4,4'-bis (dimethylamino) benzophenone and 4,4'-bis (diethylamino) benzophenone, which are available as EAB manufactured by Hodogaya Chemical Co., Ltd.

In the present invention, the component (b) accounts for 10 to 90% by weight, preferably 30 to 70% by weight, in the initiator composition comprising the component (a). If the amount of the component (b) used is smaller than the above numerical value, the curing rate is lowered, which is not preferable, and conversely, if it is larger than the above numerical value, the effect just used cannot be recognized, which is not preferable. Also, (c)
When the components are used together in the range of 1 to 10% by weight in the initiator composition, the curability can be further improved.

The photocurable coating composition of the present invention can be obtained by blending a radical diluent resin or a resin having no radical polymerizability with a reactive diluent. The radical-polymerizable resin has a weight average molecular weight of about 5,000 to 100,000 and is a resin having a viscosity of 1,000 poise or a solid at room temperature. Examples of such resins include alkyd (meth) acrylate, polyester (meth) acrylate, epoxy (meth) acrylate, urethane-modified (meth) acrylate, and modified resins obtained by modifying these raw material resins with fatty acids, rosins, higher alcohols, and the like ( Examples thereof include (meth) acrylate. As the resin having no radical polymerizable property, a resin having a softening point of 30 ° C. or higher, preferably 70 ° C. to 120 ° C. is used. Examples of the resin having no radical polymerizability include polyester resin, epoxy ester resin, urethane resin and diallyl phthalate resin.

The reactive diluent to be added to the photocurable coating composition of the present invention can be used as long as it has a viscosity of 200 poise or less (25 ° C.), but it is mainly composed of 1 to 10 poise. preferable. The following reactive diluents can be used.
Alkyl (meth) acrylates such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, (meth) acrylates of alkylene oxide adducts of alkylphenols, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, etc. Monofunctional diluent.

Ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, butylene glycol di (meth) acrylate, etc. di, tri, tetra or poly. Alkylene glycol di (meth) acrylate,
Tetramethylolmethane tetra (meth) acrylate,
Trimethylolethane tri (meth) acrylate, ditrimethylolethane tritetra (meth) acrylate,
Trimethylolpropane tri (meth) acrylate, ditrimethylolpropane tetraacrylate, glycerin tri (meth) acrylate, diglycerin tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate and the alkylene oxide (meth) of the polyols constituting them. Acrylate etc.

Bisphenol A alkylene oxide di (meth) acrylate, bisphenol F alkylene oxide di (meth) acrylate, hydrogenated bisphenol A di (meth) acrylate, hydrogenated bisphenol F di (meth) acrylate, hydrogenated bisphenol A alkylene oxide addition Di (meth) acrylate, hydrogenated bisphenol F alkylene oxide adduct di (meth) acrylate. Polylactonate di (meth) acrylate of alkylene glycol such as polyethylene glycol and polypropylene glycol, glycerin, diglycene,
Trimethylolpropane, ditrimethylolpropane,
Multifunctional diluents such as polylactonate (meth) acrylates such as pentaerythritol and dipentaerythritol.

The reactive diluent in the photocurable coating composition is
50 to 300 parts by weight is added to 100 parts by weight of the resin. The photoinitiator composition is added in an amount of 0.1 to 20 parts by weight based on the radically polymerizable compound. The use of the coating composition as a printing ink composition adds a pigment to a composition consisting of a resin, a reactive diluent and a photoinitiator. As a method for dispersing the pigment, a triple roll, a ball mill or the like can be used. A plasticizer, a surfactant and a thermal polymerization inhibitor may be added depending on the use. Moreover, you may mix | blend the resin which does not have radical polymerizability of this invention. The composition obtained is
When a printing ink or pigment is not added, it can be mainly applied as a overcoat varnish on a paper or a metal substrate by a roll coater.

[0015]

EXAMPLES The present invention will be described below with reference to examples. In the examples, parts are parts by weight. After 69.9% of dipentaerythritol hexaacrylate and 0.1% of hydroquinone were charged and heated to 100 ° C., 30 parts of diacrylic phthalate resin (DT150, manufactured by Toto Kasei Co., Ltd.) was gradually charged and dissolved, and then pumped out. A varnish having a viscosity of 2100 poise (25 ° C.) was obtained.

Using this varnish, raw materials having the following formulation were kneaded to obtain a printing ink. Base ink Carbon black 10 parts Varnish 40 parts Dipentaerythritol hexaacrylate 30 parts Pentaerythritol tetraacrylate 10 parts Initiator 10 parts

The overcoat varnish was prepared by heating and melting the raw materials of the following formulation at 50 to 80 ° C. Base clear varnish 10 parts Pentaerythritol tetraacrylate 80 parts Initiator 10 parts

The initiators used are shown below. Examples 1-
8 is an example and Examples 9 to 17 are comparative examples. m: ZLI3331 (product name manufactured by Merck) n: Esacure KIP (product name manufactured by Frater Lamberty Co.) o: EAB (product name manufactured by Hodogaya Chemical Co., Ltd.) p: Irgacure 907 (product name manufactured by Ciba-Gaigi Co., Ltd.)

Table 1 ───────────────────────────────── Example 1 2 3 4 5 6 7 8 Base ink 90 90 90 90 90 90 90 Base clear 95 Initiator m 3 7 3 4.6 2.4 Initiator n 10 7 6.5 Initiator o 0.5 0.5 0.8 0.1 Initiator p 7 5 3 3 6.5 3 4.6 2.4 Odor 3.0 3.0 4.0 4.0 3.0 4.0 3.5 4.0 Curability 60 30 40 30 70 30 40 70 Pencil hardness 3H 2H ⁺ 2H ⁺ 2H ⁺ 3H 2H ⁺ 2H ⁺ 3H ───────────────────────── ──────────

Table 2 ────────────────────────────────── Example 9 10 11 12 13 14 15 16 Base ink 90 90 90 90 90 90 90 Base clear 95 Initiator m 10 5 5 n 10 5 o 10 5 5 5 p 10 5 Odor 4.0 3.0 − 2.0 4.0 3.0 3.0 4 Curability (m) 10 15 Uncured 35 20 25 25 10 Pencil hardness (H) 2H ⁺ 2H ⁺ − 2H ⁺ 2H ⁺ 2H ⁺ 2H ⁺ 2H ⁺ ───────────────────────────── ──────

Table 3 shows comparative examples of printing inks using different initiators. Table 3 ─────────────────────────────────── Example Initiator Odor Curable 18 o-Benzoyl methyl benzoate Esters 2--19 Benzophenone 15 m / min 20 Darocur 1173 1 10 m / min 21 Darocur 2959 2 10 m / min 22 Irgacure 184 2 10 m / min 23 Irgacure 651 2 10 m / min 24 Irgacure 907 2 35 m / min 25 thioxanthone 2 26 Diethylthioxanthone 2 15 m / min 27 Seikol PAA 2 ─ 28 Kayacure EPA 2 ─ 29 Cancure BMS 3 15 m / min ────────────────────────── ────────

The performance of the printing ink was evaluated as follows. (1) Curability: In the case of printing ink in each curable coating, the ink was 0.30 cc with RI tester (20 cm x 25 c with a simple printing machine commonly used in the printing ink industry)
m of paper is uniformly printed with 0.30 cc of ink), the overcoat varnish is applied with a bar coater # 3, UV irradiation (high pressure mercury lamp 120 W / cm1 lamp) is performed, and then touch dry drying is performed. The larger the number at the UV irradiation device conveyor speed (m / min), the better the curability. Note that-is 5
Indicates less than m / min. (2) Odor: Five printed panelists judged the odor relative to each other by packing a glass bottle into which a printed matter that had been cured under the same conditions as the curability was finely cut. It was rated as (poor) 1-5 (good). . (3) Pencil hardness: The pencil hardness of the printed matter cured under the same conditions as the curability.

[0023]

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.

Claims (3)

[Claims] 1. A compound represented by the general formula (1) or a polymer of said compound: 10 to 90% by weight CH ₂ = CR ₁ CO (C ₂ H ₄ O) _n O —φ-CO—C ( CH ₃ ) _2- OR ₂
(1) (In the formula, R ₁ is H or a methyl group, R ₂ is H or CH ₂ ═CR ₁ CO group, φ is a paraphenylene group, and n is an integer of 1 to 5.) and (b) 2 -Methyl-1
[4- (Methylthio) phenyl] -2morpholinopropanone-1, 90 to 10% by weight of a photoinitiator composition. 2. The photoinitiator composition according to claim 1, further comprising (c) 1 to 10% by weight of 4,4′-bis (dilower alkylamino) benzophenone. 3. The photoinitiator composition according to claim 1 or 2 is added to a radical-polymerizable double bond-containing compound in an amount of 0.1.
A coating composition containing about 20% by weight.