JP3012065B2 - UV curable printing ink - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultraviolet-curable printing ink, and more particularly to an ultraviolet-curable printing ink that can be suitably used in lithographic printing.

[0002]

2. Description of the Related Art In recent years, the development of printing ink has been concentrated on ultraviolet-curable printing ink in terms of improving the printing environment and improving productivity by rapid curing.

[0003]

Problems to be Solved by the Invention One of the raw materials of general ultraviolet-curable printing inks is an epoxy acrylate obtained by an addition reaction between an epoxy resin and (meth) acrylic acid. In
Alcoholic hydroxyl groups are generated. Therefore, when these compounds are used in a lithographic printing ink, they are easily emulsified by a fountain solution, and have a problem in printing workability. Further, there is a problem that the water resistance of the printed matter is inferior, and further, when these compounds are used in a solder resist ink, the electric insulation properties are deteriorated. Accordingly, an object of the present invention is to provide an ultraviolet-curable printing ink having not only high-speed ultraviolet curability, but also improved printing workability based on emulsification of dampening solution, and excellent water resistance and electrical insulation properties. It is in.

[0004]

The above object is achieved by the present invention described below. That is, the present invention is an ultraviolet-curable printing ink characterized in that it contains epoxyphenyl acrylate and / or epoxyalkyl acrylate represented by the following general formula as a main component of a vehicle and further contains a photopolymerization initiator.

Embedded image (R in the above formula represents an epoxy resin skeleton, and R ′ represents a phenyl group or an alkyl group which may have a substituent.)

[0005]

By using a specific epoxy phenyl acrylate and / or epoxy alkyl acrylate as a main component of the vehicle, it is possible to improve the printing workability based on emulsification of dampening water, as well as to have high-speed ultraviolet curing properties.
An ultraviolet curable printing ink having excellent water resistance and electrical insulation properties is provided.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Next, the present invention will be described in more detail with reference to preferred embodiments. The method for producing the compound of the general formula (I) used in the constitution of the ultraviolet-curable printing ink of the present invention can be produced based on a known method. For example, one mole of an epoxy component such as 2,2- (4-hydroxyphenyl) propanediglycidyl ether and two moles of a (meth) acrylate component such as phenyl (meth) acrylate are appropriately subjected to thermal polymerization inhibition. The compound of the general formula (I) is obtained by carrying out a heat reaction in the presence of the agent. Examples of the raw materials for producing the compound of the general formula (I) include an epoxy resin component, such as a bisphenol A epoxy resin, a bisphenol F epoxy resin, a bisphenol S epoxy resin, a phenol novolak epoxy resin, and a cresol novolak epoxy resin. And glycidylamino-type epoxy resins such as tetraglycidyldianodiphenylmethane and alicyclic epoxy resins. Examples of (meth) acrylate compounds to be reacted with these epoxy resins include P-nitrophenyl (meth) acrylate,
P-chlorophenyl (meth) acrylate, phenyl (meth) acrylate, P-methylphenyl (meth) acrylate, P-methoxyphenyl (meth) acrylate, methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, Known (meth) acrylates such as lauryl (meth) acrylate can be used. Particularly preferred is phenyl (meth) acrylate which may have a substituent. Known catalysts such as a quaternary ammonium salt, a quaternary phosphonium salt and a tertiary amine can be used as a catalyst for such a reaction. The reaction between the epoxy resin and the (meth) acrylate is preferably 5
At a temperature of 0 ° C to 150 ° C, more preferably 80 ° C to 130 ° C, usually 0.1 to 10 hours, preferably 0.5 to 10 hours.
The reaction may be performed for up to 5 hours.

Next, as the photopolymerization initiator in the ultraviolet-curable printing ink of the present invention, any one can be used as long as it initiates radical polymerization upon irradiation with ultraviolet rays. Specific examples thereof include benzoin and benzoin. Benzoin and benzoin alkyl ethers such as methyl ether, benzoin ethyl ether and benzoin propyl ether; acetophenones such as acetophenone, 2,2-dimethoxy-2-acetophenone, 2,2-diethoxy-2-acetophenone and 1,1-dichloroacetophenone , 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 1-
Anthraquinones such as chloroanthraquinone, 2,4
Thioxanthones such as dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone and 2,4-diisopropylthioxanthone, ketals such as acetophenone dimethylketal and benzyldimethylmethal, benzophenones such as benzophenone and xanthones However, such a photopolymerization initiator can be used in combination with one or more known photopolymerization accelerators such as benzoic acid or tertiary amine. And, as the usage amount of such a photopolymerization initiator,
For 100 parts by weight of the ultraviolet curable resin (I),
A ratio of 0.2 to 30 parts by weight, preferably 2 to 20 parts by weight is suitable.

The ultraviolet-curable vehicle (I) of the present invention comprises:
It is preferable to use 2 to 80 parts by weight, preferably 20 to 50 parts by weight of the total amount of the ink in the ink formulation. When the ultraviolet curable vehicle (I) is used in an amount of more than 80 parts by weight, the fluidity of the printing ink is lost and handling becomes difficult, which is not preferable. On the other hand, the use amount of the photopolymerization initiator is not practical because when used in a small amount outside the above range, the ultraviolet curability of the printing ink becomes insufficient.
In addition, although a large amount may be used outside the above range, a photopolymerization initiator not used at the time of exposure remains in the ink coating film, and there is a further economic problem. The ultraviolet-curable printing ink of the present invention includes a vehicle represented by the general formula (I),
In addition to the photopolymerization initiator and the coloring pigment, other monomers, oligomers, polymerization inhibitors, plasticizers, thickeners, and other auxiliaries can be used as needed.

[0009]

Next, the present invention will be described more specifically with reference to examples and comparative examples. In the following, "parts" and "%" are based on weight unless otherwise specified. Example 1 3.2 parts of tetrabutylammonium bromide (TBAB) as a catalyst were added to 37.2 parts of Epikote 828 (manufactured by Yuka Shell Co., Ltd., epoxy equivalent: 186) and 38.6 parts of P-nitrophenyl acrylate. Add 0.5 part of hydroquinone monomethyl ether (MQ) and add
The reaction was carried out at a temperature of 5 ° C. for 5 hours to obtain the desired epoxy P-nitrophenyl acrylate. This compound is designated as EA-1. EA-1 45 parts Fast Gemble-TGR (Dainippon Ink & Chemicals, Inc.) 20 parts Benzophenone 6 parts 4,4'-diethylaminobenzophenone 2 parts Hydroquinone monomethyl ether 0.1 parts Trimethylolpropane triacrylate 25 parts Polyethylene 1 part of wax 100.1 parts The above components were uniformly mixed to prepare an ultraviolet-curable printing ink of the present invention.

Example 2 3.2 parts of TBAB and 0.5 part of MQ were used as catalysts in 37.2 parts of Epicoat 828 (epoxy equivalent: 186, manufactured by Yuka Shell Co., Ltd.) and 36.4 parts of P-chlorophenyl acrylate. In addition, the mixture was reacted at 100 ° C. for 5 hours to obtain the desired epoxy P-nitrophenyl acrylate. This compound is referred to as EA-2. EA-2 45 parts Fast Gemble-TGR (manufactured by Dainippon Ink and Chemicals, Inc.) 20 parts Benzophenone 6 parts 4,4'-diethylaminobenzophenone 2 parts MQ 0.1 part Trimethylolpropane triacrylate 25 parts Polyethylene wax 2 Part 100.1 parts The above components were uniformly mixed to prepare an ultraviolet-curable printing ink of the present invention.

Example 3 To 37.2 parts of Epikote 828 and 29.6 parts of phenyl acrylate, 3.2 parts of TBAB as a catalyst and MQ
0.5 part was added and reacted at 100 ° C. for 5 hours to obtain the desired epoxyphenyl acrylate. This compound is referred to as EA-3. EA-3 45 parts Fast Gemble-TGR (manufactured by Dainippon Ink and Chemicals, Inc.) 20 parts Benzophenone 6 parts 4,4'-diethylaminobenzophenone 2 parts MQ 0.1 part Trimethylolpropane triacrylate 25 parts Polyethylene wax 2 Part 100.1 parts The above components were uniformly mixed to prepare an ultraviolet-curable printing ink of the present invention.

EXAMPLE 4 37.2 parts of Epikote 828 and 32.4 parts of P-methylphenyl acrylate were combined with TBAB 3.2 as a catalyst.
And 0.5 parts of MQ were added and reacted at 100 ° C. for 5 hours to obtain the desired epoxy P-methylphenyl acrylate. This compound is designated as EA-4. EA-4 45 parts Fast Gemble-TGR (manufactured by Dainippon Ink and Chemicals, Inc.) 20 parts Benzophenone 6 parts 4,4'-diethylaminobenzophenone 2 parts MQ 0.1 part Trimethylolpropane triacrylate 25 parts Polyethylene wax 2 Part 100.1 parts The above components were uniformly mixed to prepare an ultraviolet-curable printing ink of the present invention.

Comparative Example 1 Lipoxy SP1509 (manufactured by Showa Polymer Co., Ltd.) 50 parts Fast Gemble-TGR (manufactured by Dainippon Ink and Chemicals, Inc.) 20 parts Benzophenone 6 parts 4,4'-diethylaminobenzophenone 2 parts MQ 0.1 part Trimethylolpropane triacrylate 20 parts Polyethylene wax 2 parts 100.1 parts The above components were uniformly mixed to prepare an ultraviolet curable printing ink of a comparative example.

Using the inks in the above examples, Heidel KO
Printing was performed using an RD printer, and the following items were evaluated. (1) Emulsification resistance Evaluation was made by observing the emulsified state of the ink on the kneading roller and the ink retrieving roller and the piling of the ink forming roller. (2) Remaining plate-blanket After continuous printing of 2,000 sheets, the operation of the printing press was stopped, and the remaining state of the ink on the plate and the blanket was evaluated by finger touch. (3) Curability After the ink was colored on a Uto cardboard with a RI tester manufactured by Ming Co., Ltd. so that the thickness of the ink became 2 μm, this was mounted on a single-tube high-pressure mercury lamp with a total length of 25 cm and an output of 2 Kw equipped with a condensing reflector. Light was irradiated by placing and passing a 10 cm lower part on a variable traveling speed conveyor that travels in a direction perpendicular to the long axis of the lamp, and irradiated with light, and the conveyor speed required for touch drying was evaluated.

(4) Gloss With the RI tester, the ink film thickness on the art paper is 2 μm.
m, and the gloss of the ink film completely cured by the above-mentioned ultraviolet irradiation device was measured at a reflection angle of 60 ° using a gloss meter (Murakami Color Research Laboratory, gloss meter GM260 type). (5) Water resistance The above-mentioned RI tester is used to spread the color of the ink on the aluminum foil so that the film thickness becomes 2 μm, and the developed product completely cured by the ultraviolet irradiation device is placed in water at 25 ° C. Evaluation was made based on the peeling of the ink and the decrease in gloss. (6) Surface resistance In accordance with JIS-C2560, each ink spread on a glass plate with an RI tester has the normal insulation property and
The insulation properties after moisture absorption at 5 ° C. and 95% RH for 500 hours were indicated as 1 minute value at 500 V DC using “Hiresta” manufactured by Mitsubishi Yuka Corporation. (7) Tack (TV) Measured at 90 ° F. and 400 rpm with an incometer. (8) Dynamometer (DM value) Measured by a parallel plate viscometer at 25 ° C. for 5 minutes.
Table 1 below shows the test results for the above items.
Similarly, the columns of printability and water resistance are displayed according to the criteria of excellent 5, excellent 4, good 3, slightly poor 2, and poor 1.

[0016]

[Table 1]

[0017]

As is clear from the examples shown above, it is clear that the ultraviolet-curable printing ink of the present invention has remarkably excellent printability, curability, water resistance and electrical properties. .

Claims (3)

(57) [Claims] 1. An ultraviolet-curable printing ink comprising an epoxyphenyl acrylate and / or an epoxyalkyl acrylate represented by the following general formula as a main component of a vehicle and further containing a photopolymerization initiator. Embedded image (R in the above formula represents an epoxy resin skeleton, and R ′ represents a phenyl group or an alkyl group which may have a substituent.) 2. Epoxy phenyl acrylate and / or epoxy alkyl acrylate are used in an amount of 2 to 2 parts of the total amount of the ink.
The ultraviolet-curable printing ink according to claim 1, which contains 80% by weight. 3. The method of claim 1, wherein the photopolymerization initiator is epoxyphenyl acrylate and / or epoxyalkyl acrylate.
0.2 to 30 parts by weight per 0 parts by weight.
3. The ultraviolet-curable printing ink according to 2.