JPH04323275A - Composition for printing ink and cured material thereof - Google Patents

Abstract

PURPOSE:To obtain a composition for printing ink having excellent stability of liquid composition and high curing rate and little in discoloration of cured material, containing a polyurethane (meth)acrylate and N-vinyl-epsilon-caprolactam. CONSTITUTION:The objective composition suitable for ultraviolet-curing type screen printing ink comprising (A) a polyurethane (meth)acrylate obtained by reacting a polyol compound with an organic diisocyanate and a hydroxyl group- containing (meth)acrylic acid ester until isocyanate group is exhausted, (B) N-vinyl-epsilon-caprolactam and optionally (C) phenylglycidyl ether acrylate, a photopolymerization initiator, etc.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing ink composition particularly suitable for use as an ultraviolet curable screen printing ink and a cured product thereof.

0002

[Prior Art] Photocurable compositions containing polyurethane acrylate are known, for example, from JP-A-48-25095 and JP-A-48-25095.
-133491, No. 57-83562, and the like. Moreover, the proportion of these materials used in printing inks and coating agents is increasing.

0003

[Problems to be Solved by the Invention] Since polyurethane acrylate has a high viscosity, it is necessary to dilute it with a low-viscosity monomer before use. Currently, N-vinyl pyrrolidone is often used as a diluent due to problems in adhesion to various base materials (eg, polyvinyl chloride, polycarbonate, polymethacrylic resin, etc.). By using N-vinyl pyrrolidone, it is possible to create printing inks, coatings, etc. with excellent curability and adhesion, but compositions containing N-vinyl pyrrolidone tend to thicken over time. It may turn into a gel or become colored. In addition, the cured product is colored, which is a problem especially in the case of compositions containing white pigments (titanium oxide, etc.).

0004

[Means for Solving the Problems] In order to solve the above-mentioned problems, the inventors of the present invention have made extensive research and have developed a printing ink that has good liquid composition stability, fast curing speed, and less coloring of the cured product. The present invention has been completed by successfully providing a composition for That is, the present invention relates to a printing ink composition characterized by containing polyurethane (meth)acrylate and N-vinyl-ε-caprolactam, and a cured product of the printing ink composition according to item 1. be.

The polyurethane (meth)acrylate used in the present invention can be obtained by reacting a polyol compound, an organic diisocyanate, and a (meth)acrylic acid ester having a hydroxyl group until the polyurethane (meth)acrylate contains substantially no NCO groups. Typical polyol compounds include ethylene glycol, propylene glycol, 1,3-butylene glycol, neopentyl glycol, cyclohexanedimethanol, tricyclodecane dimethylol, 1,4-butanediol, and 1,6- Polyols such as hexanediol and trimethylolpropane,
polypropylene glycol, polyethylene glycol,
Polyether polyols such as polytetramethylene glycol, propylene glycol-modified polytetramethylene glycol, trimethylolpropane polyethoxy, trimethylolpropane polypropoxy, the above polyols or polyether polyols, or the above polyols containing ε-
A compound to which caprolactone or valerolactone is added is used as the alcohol component, and one acid component is a dibasic acid such as adipic acid, sebacic acid, azelaic acid, dodecanedicarboxylic acid, phthalic acid, tetraphthalic acid, hexahydrophthalic acid, etc. and anhydrides thereof, and polycarbonate polyols containing the above-mentioned polyols, polyether polyols, and polyester polyols as alcohol components. Typical organic diisocyanates include aromatic diisocyanates such as tolylene diisocyanate and 4,4'-diphenylmethane diisocyanate, alicyclic diisocyanates such as isophorone diisocyanate and 4,4'-dicyclohexylmethane diisocyanate, and hexamethylene diisocyanate. , 2,2'-trimethylhexamethylene diisocyanate and other aliphatic diisocyanates. The ratio of the polyol compound and the organic diisocyanate used in the urethanization reaction is preferably 1.1 to 2.0 chemical equivalents of the NCO group of the organic diisocyanate per 1 chemical equivalent of the OH group of the polyol compound. Particularly preferred is 1.5 to 2.0 chemical equivalents. This urethanization reaction can be carried out in procedures known to those skilled in the art. The reaction temperature of this urethanization reaction is usually room temperature to 100°C, preferably 50 to 100°C.
The temperature is 80°C. Then, in the (meth)acrylation reaction, the OH of the (meth)acrylic acid ester having a hydroxyl group is The group preferably has a chemical equivalent of 0.9 to 1.5,
Particular preference is given to using 1.0 to 1.1 chemical equivalents. Representative examples of (meth)acrylic acid esters having a hydroxyl group include β-hydroxyethyl (meth)acrylate, β-hydroxypropyl (meth)acrylate, and ε-caprolactone-β-hydroxyethyl (meth)acrylate.
Examples include acrylate, pentaerythritol triacrylate, dipentaerythritol pentaacrylate, and the like. For this reaction, 50 to 2000 p was added to the reaction mixture to prevent gelation due to radical polymerization during the reaction.
It is preferable to add a polymerization inhibitor such as pm hydroquinone, hydroquinone monomethyl ether, P-methoxyphenol, and P-benzoquinone. Further, the reaction temperature of this acrylation reaction is usually room temperature to 100°C, preferably 50 to 80°C. The reaction between NCO groups and OH groups proceeds without a catalyst, but for example, tertiary amines such as triethylamine, organometallic compounds such as dibutyltin dilaurylate and dibutyltin diacetate, or tin chlorides, etc. Conventional catalysts may also be used. Further, 0.5 of the OH group of the (meth)acrylic acid ester having the hydroxyl group per 1 chemical equivalent of the NCO group of the organic diisocyanate.
For one chemical equivalent of the NCO group of the reactant with the chemical equivalent,
The OH group of the polyol compound is preferably 0.5 to 1
Polyurethane (meth)acrylate obtained by reacting with a chemical equivalent can also be used.

Preferred polyurethane (meth)acrylates include polyether polyurethane acrylate and polyester polyurethane acrylate. The amount of polyurethane (meth)acrylate used is 10 to 8 of the printing ink composition (excluding pigments and fillers).
0% by weight is preferred, particularly preferably 20-70% by weight.

[0007] N-vinyl-ε-caprolactam used in the present invention is easily available on the market. N-
The amount of vinyl-ε-caprolactam used is preferably 5 to 60% by weight, particularly preferably 10 to 50% by weight of the printing ink composition (excluding pigments and fillers).

In the printing ink composition of the present invention, various known ethylenically unsaturated compounds can be used as components other than polyurethane (meth)acrylate and N-vinyl-ε-caprolactam. Typical examples of ethylenically unsaturated compounds include tetrahydrofurfuryl acrylate, carbitol acrylate, phenoxyethyl acrylate, isobornyl acrylate, and hydrogenated dicyclopentadiene acrylate (manufactured by Hitachi Chemical Co., Ltd., FA-51).
3A), tricyclodecane dimethylol diacrylate, hydroxypivalate neopentyl glycol diacrylate, trimethylolpropane triacrylate,
Polyethylene glycol diacrylate, phenylglycidine ether acrylate, 1,6-hexanediol acrylate, glycerin monoacrylate, epoxy acrylate (e.g. bisphenol A epoxy resin acrylate, bisphenol F epoxy resin acrylate, bisphenol A urethane-modified epoxy resin) acrylate, etc.), polyester acrylate (e.g., ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol,
, 5-pentanediol, 1,6-hexanediol and other diol components and acrylates of polyester diols consisting of dibasic acids such as succinic acid, adipic acid, phthalic acid, hexahydrophthalic acid, and tetrahydrophthalic acid; Acrylate of lactone-modified polyester diol consisting of dibasic acid and ε-caprolactone or valerolactone), polycarbonate acrylate (
For example, acrylates of polycarbonate diol containing 1,6-hexanediol as a diol component, etc.) can be mentioned.

Particularly preferred ethylenically unsaturated compounds include, for example, phenylglycidyl ether acrylate, phenoxyethyl acrylate, hydrogenated dicyclopentadiene acrylate, and tetrahydrofurfuryl acrylate. The above-mentioned ethylenically unsaturated compounds may be used alone or in combination of two or more compounds in any proportion as required.

[0010] The amount of the ethylenically unsaturated compound used in the printing ink composition (excluding pigments and fillers) is 0 to 50%.
% by weight is preferred, and 20-40% by weight is particularly preferred. These ethylenically unsaturated compounds are easily available on the market. The cured product of the printing ink composition of the present invention can be obtained by irradiating and curing with ultraviolet rays or electron beams in a conventional manner. For example, in the case of curing with ultraviolet rays, it is preferable to use a photopolymerization initiator in combination. The photopolymerization initiator may be any known photopolymerization initiator, but it is required to have good storage stability after blending. Examples of such photopolymerization initiators include benzoin alkyl ethers such as benzoin ethyl ether, benzoin isobutyl ether, and benzoin isopropyl ether;
Acetophenone series such as 2,2-diethoxyacetophenone and 4'-phenoxy-2,2-dichloroacetophenone, 2-hydroxy-2-methylpropiophenone,
4'-isopropyl-2-hydroxy-2-methylpropiophenone, 4'-dodecyl-2-hydroxy-2-
Propiophenone series such as methylpropiophenone, benzyl dimethyl ketal, 1-hydroxycyclohexylphenyl ketone (manufactured by Ciba Geigy, Irgacure 184), anthraquinone series such as 2-ethylanthraquinone, 2-chloroanthraquinone, etc. ,
Examples include thioxanthone photopolymerization initiators. Particularly preferred examples include benzyl methyl ketal, 1-hydroxycyclohexylphenyl ketone, and diethyl thioxanthone. These photoinitiators are
One kind or two or more kinds may be mixed and used in any proportion.

The amount used is usually 0 to 10% by weight, preferably 3 to 7% by weight of the printing ink composition (excluding pigments and fillers). The printing ink composition of the present invention can be obtained by mixing and dissolving polyurethane (meth)acrylate, N-vinyl-ε-caprolactam, and, if necessary, the ethylenically unsaturated compound and photopolymerization initiator. can. The printing ink composition of the present invention may contain non-reactive resins, pigments, and various other fillers and additives, if desired. Non-reactive resins include polyester resins, alkyd resins, phenolic resins,
Polyurethane, polybutadiene, polystyrene, poly(
Examples include meth)acrylate polymers and epoxy resins. The fillers and additives include talc, aluminum oxide, barium sulfate, silane coupling agents, leveling agents, antifoaming agents, antioxidants, light stabilizers,
Examples include polymerization inhibitors. When the printing ink composition of the present invention is used as an ultraviolet curable screen printing ink, a screen printing method is suitable as the printing method. It is printed on a substrate (for example, polycarbonate, polyvinyl chloride, etc.) to a thickness of 10 to 30 microns by screen printing, and then cured by irradiation with ultraviolet light. When the printing ink composition of the present invention is cured with an electron beam, it is not necessary to add the photopolymerization initiator described above.

0012

[Examples] The present invention will be specifically explained below using examples. In addition, parts in the synthesis examples and examples are parts by weight. Synthesis of polyurethane (meth)acrylate

Synthesis Example 1 In a 2-liter reactor equipped with a stirrer, a temperature controller, a thermometer, and a condenser, 230 parts of polyester diol (a polyester diol with a molecular weight of 480 produced from neopentyl glycol and adipic acid) and polytetra Methylene glycol (manufactured by Hodogaya Chemical Co., Ltd., PTG-500p,
244.8 parts (molecular weight: about 2000) and 200 parts of isophorone diisocyanate were charged, and after raising the temperature, the reaction was carried out at 75°C for 10 hours.Then, the reaction solution was cooled to 60°C, and 68.7 parts of 2-hydroxyethyl acrylate and 0.0 parts of methoquinone were added. 37 parts and 0.14 parts of di-n-butyltin dilaurate were added, and after raising the temperature, the reaction was carried out at 75 to 80°C. The reaction was continued upon completion as indicated by less than about 0.1% free isocyanate groups. The product has the following properties. Viscosity 1510 Poise (
60℃)

Synthesis Example 2 Into the same reactor as in Synthesis Example 1, 430.9 parts of polypropylene glycol (manufactured by Sanyo Kasei Co., Ltd., SANNIX PP-2000, molecular weight 2000) and 427 parts of polytetramethylene glycol (molecular weight 2000) were added. , 187.7 parts of tricyclodecane dimethylol and 620.4 parts of isophorone diisocyanate were charged, and after raising the temperature, they were reacted at 80°C for 10 hours.Then, the reaction solution was cooled to 60°C, and 334 parts of 2-hydroxyethyl acrylate and methoquinone were charged. 1.0 parts and 0.4 parts of di-n-butyltin dilaurate were added, and after raising the temperature, the reaction was carried out at 75 to 80°C. The reaction was continued until completion as indicated by less than about 0.1% free isocyanate groups. The product has the following properties. Viscosity (60℃) 6600pois
e

Synthesis Example 3 In the same reactor as in Synthesis Example 1, polyester diol (composed of neopentyl glycol and adipic acid with a molecular weight of 48
0 polyester diol) 384 parts, propylene glycol modified polytetramethylene glycol (manufactured by Hodogaya Chemical Co., Ltd., PPTG-2000, molecular weight 2000) 4
00 parts and Coronate 2094 (diisocyanate compound manufactured by Nippon Polyurethane Co., Ltd., hydrogenated bisphenol A1
864 parts of a reaction product (NCO%: 14.6%) of 2 moles of hexamethylene diisocyanate and 2 moles of hexamethylene diisocyanate were charged, and after raising the temperature, the reaction was carried out at 80°C for 10 hours.Then, the reaction solution was cooled to 60°C, and 2-hydroxy 176.4 parts of ethyl acrylate and 0.9 parts of methoquinone were charged, and the temperature was raised to 75-80°C.
The reaction was carried out. The reaction was continued until completion as indicated by less than about 0.1% free isocyanate groups. The product has the following properties. Viscosity (60℃) 6800pois
e

Printing ink composition Example 1 28 parts of polyurethane acrylate obtained in Synthesis Example 1, N-
Vinyl-ε-caprolactam 28 parts, phenylglycidine ether acrylate 14 parts, Irgacure 184
(manufactured by Ciba Geigy Co., Ltd., photopolymerization initiator) 2 parts, diethylthioxanthone (manufactured by Nippon Kayaku Co., Ltd., KAYACU)
RE, DETX, photopolymerization initiator) 1 part, N,N-dimethylaminobenzoic acid ethyl ester (Nippon Kayaku Co., Ltd.)
KAYACURE EPA, Co., Ltd., 2 parts of photopolymerization accelerator), 0.035 parts of methoquinone (polymerization inhibitor), and 30 parts of titanium dioxide (white pigment) were mixed and kneaded with three rolls to prepare the printing ink of the present invention. Composition A was obtained. Table 1 shows the properties of the liquid composition and cured product.

Example 2 35 parts of polyurethane acrylate obtained in Synthesis Example 2, N-
Vinyl-ε-caprolactam 35 parts, Irgacure 1
84, 2 parts of diethylthioxanthone, 2 parts of N,N-dimethylaminobenzoic acid ethyl ester, 0.035 parts of methoquinone (polymerization inhibitor) and 30 parts of titanium dioxide were mixed, kneaded with three rolls, and A printing ink composition B of the invention was obtained. Table 1 shows the properties of the liquid composition and cured product.

Example 3 28 parts of polyurethane acrylate obtained in Synthesis Example 3, N-
21 parts of vinyl-ε-caprolactone, 7 parts of tetrahydrofurfuryl acrylate, hydrogenated dicyclopentadiene acrylate (manufactured by Hitachi Chemical Co., Ltd., FA-513A) 14
1 part, Irgacure 184, 2 parts, 1 part of diethylthioxanthone, 2 parts of N,N-dimethylaminobenzoic acid ethyl ester, 0.035 part of methoquinone (polymerization inhibitor) and 30 parts of titanium dioxide were mixed, and mixed with three rolls. By kneading, a composition C for printing ink of the present invention was obtained. Table 1 shows the properties of the liquid composition and cured product.

Example 4 21 parts of polyurethane acrylate obtained in Synthesis Example 1, N-
21 parts of vinyl-ε-caprolactam, 14 parts of phenyl glycidyl ether acrylate, 14 parts of phenoxyethyl acrylate, 2 parts of Irgacure 184, 1 part of diethylthioxanthone, 2 parts of N,N-dimethylaminobenzoic acid ethyl ester, methquinone (polymerization inhibitor) 0.03
5 parts of titanium dioxide and 30 parts of titanium dioxide were mixed and kneaded using three rolls to obtain a printing composition D of the present invention. Table 1 shows the properties of the liquid composition and cured product.

Example 5 In the printing ink composition of Example 1, 2 parts of Irgacure 184, 1 part of diethylthioxanthone, N,N-
Printing ink composition E was prepared in the same manner as in Example 1 except for 2 parts of dimethylaminobenzoic acid ethyl ester. Table 1 shows the properties of the liquid composition and cured product.

Comparative Example 1 A printing ink composition F was obtained in the same manner as in Example 1 except that N-vinylpyrrolidone was used instead of N-vinyl-ε-caprolactam. Table 1 shows the properties of the liquid composition and cured product.

Comparative Example 2 The formulation of Example 2 except that N-vinylprolidone was used instead of N-vinyl-ε-caprolactam.
Printing ink composition G was obtained in the same manner. Table 1 shows the properties of the liquid composition and cured product.

[0023]
Table 1
Printing ink composition A
B C D E
FG curability (mj/cm2)
270 405 540
405 5 mega 405 270


Rat stainability ○
○ ○ ○ ○
× ×Adhesion
○ ○ ○
○ ○ ○ ○Stability of liquid Gelation Gelation Gelation
Gelation Gelation Gelation Gelation
I'm doing it. I'm doing it. I'm doing it. I'm doing it. I'm doing it.
No No No No
do not have

The printing ink compositions of curability A, B, C, D, F and G in Table 1 above were printed on a 1 mm thick polycarbonate resin using a screen (thickness 15 μm), and then 8 cm below the light source with high pressure mercury lamps (lamp output 2 kW) arranged in parallel.
It was cured by irradiation at the position (conveyor speed 5 m/min). The irradiation amount (mj/cm2) until curing was determined. Composition E was printed on a 1 mm thick polycarbonate resin using a screen (thickness: 15 μm), and then irradiated with an electron beam using an electron beam irradiation device (175 KeV), and the irradiation amount until curing ( Megarat) was sought.

Colorability: The printed matter cured by the above method was
The degree of coloring of the printed surface after being left at 0° C. for 24 hours was observed. ○─── There is almost no discoloration. △────Slightly discolored. ×─── Significant discoloration. Adhesion: Cross-cut the print cured using the above method.
A Sellotape peel test was conducted. ○─── No peeling or cracking occurs at all. △────There is a slight chip in the eye. ×─── Peeling and chipping of the eyes occurred. Liquid stability: Put 100g of printing ink compositions A, B, C, D, E, and F into a brown 100ml polybottle,
The mixture was left at 70°C, and after 30 days, the presence or absence of gelation was observed.

[0026]

Effects of the Invention The printing ink composition of the present invention is particularly suitable for ultraviolet curable screen printing inks, which have good liquid composition stability, fast curing speed, and little discoloration of the cured product.

Claims (2)

[Claims] Claim 1: Polyurethane (meth)acrylate and N-
A printing ink composition containing vinyl-ε-caprolactam. 2. A cured product of the printing ink composition according to claim 1.