JP3119282B2 - UV-curable printing ink composition - 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 composition, and more particularly to an ultraviolet-curable printing ink composition for screen printing.

[0002]

2. Description of the Related Art In recent years, UV curable printing inks for screen printing inks are superior to solvent-based inks in terms of occupational safety and health, environmental pollution, fire prevention, etc. because they do not contain solvents. In addition, they are widely used because they are made to react by electromagnetic waves called ultraviolet rays, so that the reaction efficiency is high and the printing productivity is improved. Conventional UV-curable printing inks are disclosed in JP-B-54-15473 and JP-A-63-1.
No. 17023, JP-A-2-202563, JP-A-3-220218, and the like.

[0003]

However, these known ultraviolet curable printing inks have satisfactory curability and adhere to the material, but the cured film is too hard or
Despite its flexibility, it is inadequately adhered, so it can be overprinted and post-processed on the printing material (drawing, bending, etc. of the material)
Had a problem. An object of the present invention is to provide an ultraviolet-curable printing ink that solves these various problems.

[0004]

According to the present invention, there is provided an ink which achieves the above object by a composition wherein the polyurethane acrylate oligomer is a polycaprolactone-based urethane acrylate oligomer and contains vinylcaprolactam and phenoxyethyl acrylate as essential components. I can make it. That is, in this UV-curable composition, a photopolymerization initiator, a pigment, a matting agent, an additive capable of adjusting printability, and the like are added to form an ink. It is possible.

The polyurethane acrylate oligomer used in the present invention is a polycaprolactone-based urethane acrylate oligomer, which can be synthesized by reacting a polycaprolactone-based polyol with an organic polyisocyanate and hydroxyacrylate.

The polycaprolactone-based polyol which can be used in the present invention is not particularly limited, but is a compound having two hydroxyl groups and preferably has a number average molecular weight of 850 to 2,000. It is easily available. Further, in order to obtain the polycaprolactone-based urethane acrylate oligomer of the present invention, other polyol compounds such as polytetramethylene ether glycol, polyethylene glycol, ethylene glycol, diethylene glycol, and 1.4-butane are used in addition to the starting material polycaprolactone-based polyol. Various known polyols such as diol and 1.6-hexanediol can be used alone or in a mixture of more than one in an arbitrary ratio.

The organic polyisocyanate which can be used in the present invention preferably has two isocyanate groups. For example, known organic polyisocyanates such as isophorone diisocyanate, hexamethylene diisocyanate, 4.4'-dicyclohexylmethane diisocyanate and trimethylhexamethylene diisocyanate. It is a non-yellowing type. The hydroxy acrylate that can be used in the present invention includes 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, caprolactone-modified 2-hydroxyethyl acrylate, and the like.

The polycaprolactone-based urethane acrylate oligomer can be synthesized by the reaction of the above-mentioned polycaprolactone-based polyol, an organic polyisocyanate and hydroxyacrylate. The synthesis method is based on a known conventional catalyst, temperature, time and the like. By first reacting a caprolactone-based polyol with an organic polyisocyanate, a polyurethane prepolymer containing -NCO groups at both ends is produced, and finally reacted with hydroxyacrylate to obtain a polycaprolactone-based urethane acrylate oligomer. .

The number average molecular weight of the polycaprolactone-based urethane acrylate oligomer that can be used in the present invention is as follows:
2,500 to 10,000 are preferred. When the number average molecular weight is 2,500 or less, the cured film becomes hard when formed into a printing ink composition, and when the number average molecular weight is 10,000 or more, the curing speed is reduced. In addition, polycaprolactones that can be used in the present invention
Urethane acrylates include polyurethanes with other structures.
Tanacrylate oligomers such as polyester-based urethane
Tan acrylate oligomer, polyether urethane
An acrylate oligomer or the like can be arbitrarily mixed and used,
Furthermore, epoxy acrylate oligomer, polyester
Mix and use oligomers etc. for the purpose of improving film properties
I can do it. In the present invention, the photopolymerizable monomer to be combined with the polycaprolactone-based urethane acrylate oligomer as described above is vinylcaprolactam and phenoxyethyl acrylate as essential components (hereinafter referred to as a vehicle component). Based on 100 parts by weight of the caprolactone-based urethane acrylate oligomer, vinyl caprolactam is 5 to 100 parts by weight, preferably 10 to 80 parts by weight, and phenoxyethyl acrylate is 80 to 250 parts by weight, preferably 100 to 250 parts by weight.
It is 200 parts by weight. Also, vinylcaprolactam and phenoxyethyl acrylate can be easily obtained industrially.

Further, in the present invention, in addition to vinylcaprolactam and phenoxyethyl acrylate, a photopolymerizable monofunctional monomer, bifunctional monomer and the like can be added as long as the object of the present invention is not reduced. As monofunctional monomers, for example, acryloyl morpholine,
Ethyl carbitol acrylate, isobornyl acrylate, NN-dimethyl acrylamide, dicyclopentenyl acrylate, 2-ethylhexyl acrylate, and the like. As the bifunctional monomer, 1.6-hexanediol diacrylate, tetraethylene glycol diacrylate, Neopentyl glycol diacrylate, bisphenol A or hydrogenated bisphenol A type alkylene oxide adduct diacrylate, tripropylene glycol diacrylate and the like can be mentioned. These photopolymerizable monofunctional monomers and bifunctional monomers can be used in an amount of 0 to 20 parts by weight based on the vehicle component of the present invention.

The photopolymerization initiator used in the present invention can be selected from the following known compounds. For example, benzophenones, benzyl dimethyl ketal, 1-hydroxycyclohexyl phenyl ketone, carbonyl compounds such as methylbenzoyl formate, thioxanthones,
2.4.6-Trimethylbenzoyldiphenylphosphine oxide and other phosphorus compounds, 2-methyl-1- [4
-(Methylthio) phenyl] -2-morpholinopropane-1 and the like. These compounds can be used by combining one or more of these compounds, and are known from the viewpoint of promoting photopolymerization. Sensitizers can also be added. As the sensitizer, for example, amine compounds such as triethanolamine and P-dimethylaminobenzoic acid isoamyl ester are useful, and the addition amount of the sensitizer of the photopolymerization initiator is based on the vehicle component of the present invention. 2-10
% By weight is preferred.

In the present invention, when an ultraviolet-curable printing ink is obtained using the vehicle component, the pigment used is:
In general, commercially available inorganic coloring pigments, organic coloring pigments, organic extenders, inorganic matting powder pigments, organic matting powder pigments, and the like are available. The pigment is used for the purpose of the ink, for example,
It is composed of one or more compounds depending on the purpose of matting or the like. The mixing ratio of the pigment is determined within a range that does not inhibit the ultraviolet curing and does not lower the object of the present invention, and is preferably used in an amount of 1 to 100 parts by weight based on the vehicle component.

Among the ultraviolet-curable printing inks of the present invention, defoaming agents, leveling agents, pigment wetting agents, dispersants, flow regulators which are generally commercialized for the purpose of adjusting the ink and printability. , A thermal polymerization inhibitor, an oxidation polymerization inhibitor, and the like. The material of the material to which the ultraviolet-curable printing ink composition of the present invention is applied is a plastic, and particularly has excellent adhesion to polycarbonate plates and films, PVC films and stickers, acrylic plates, treated PET, painted metals, and the like. doing.

[0014]

EXAMPLES The present invention will be described below in detail with reference to examples, but the present invention is not limited to these examples. The present invention will be described based on specific examples (A, B, C) in which the number average molecular weight of the polycaprolactone-based urethane acrylate oligomer used in the present invention is changed. Further, the results of a property test in which the polyester-based urethane acrylate oligomer (D) and the polyether-based urethane oligomer (E) are compared with the polycaprolactone-based urethane acrylate oligomer of the present invention will be described below.

[0015] Formulation examples, comparative compounding agents, and characteristic tests of white ink, black ink, and blue ink prepared with the ultraviolet-curable printing ink composition of the present invention are shown. (Sample: polyurethane acrylate oligomer) A: Polycaprolactone urethane acrylate oligomer having a number average molecular weight of about 5,000 B: Polycaprolactone urethane acrylate oligomer having a number average molecular weight of about 3,500 C: Polycaprolactone urethane acrylate oligomer having a number average molecular weight of about 8,000 D : Polyester urethane acrylate oligomer having a number average molecular weight of about 3,500 E: Polyether urethane acrylate oligomer having a number average molecular weight of about 10,000 [Formulation Examples] Formulation Examples 1 to 3 and 6 show examples of white ink formulation. Formulation Examples 4, 5, 7 to 10 show comparative formulation examples of white ink. Formulation Examples 11 to 13 and 16 show formulation examples of black ink. Formulation Examples 14, 15 and 17 to 20 show comparative formulation examples of black ink. Formulation Example 21 shows a formulation example of the blue ink. [Remarks] Irgacure 651 ... A product name manufactured by Nippon Bagagii Co., Ltd.
Chemical name is benzyl dimethyl ketal lucirin TPO ... trade name of BASF, chemical name is 2.
4.6-Trimethylbenzoyldiphenylphosphine oxide

[0016]

[Table 1-1]

[0017]

[Table 1-2]

[0018]

[Table 1-3]

[0019]

[Table 1-4]

[0020]

[Table 1-5]

Formulation Example 1 15 parts by weight of a polycaprolactone-based urethane acrylate oligomer having a number average molecular weight of about 5,000 synthesized by a reaction of a polycaprolactone-based polyol, an organic polyisocyanate, and hydroxyacrylate as an oligomer, and vinylcaprolactam as a photopolymerizable monomer 5 parts by weight
1. 25 parts by weight of phenoxyethyl acrylate, 4 parts by weight of benzyldimethyl ketal as a photopolymerization initiator (trade name: Irgacure 651, manufactured by Nippon Bagaigie Co., Ltd.)
4.6-trimethylbenzoyldiphenylphosphine oxide 1 part by weight (manufactured by BASF, trade name Lucilin TPO), 1 part by weight of a silicone-based antifoaming agent as an antifoaming agent,
2 parts by weight of an acrylic leveling dispersant as an additive,
An ultraviolet curable white ink composition for printing was obtained at a mixing ratio of 50 parts by weight of a pigment containing titanium oxide as a main component.
(Formulation Example 1)

Formulation Example 2 15 parts by weight of a polycaprolactone-based urethane acrylate oligomer having a number average molecular weight of about 3,500 synthesized by the reaction of a polycaprolactone-based polyol, an organic polyisocyanate and hydroxyacrylate as an oligomer, and vinylcaprolactam as a photopolymerizable monomer 5 parts by weight
1. 25 parts by weight of phenoxyethyl acrylate, 4 parts by weight of benzyldimethyl ketal as a photopolymerization initiator (trade name: Irgacure 651, manufactured by Nippon Bagaigie Co., Ltd.)
4.6-trimethylbenzoyldiphenylphosphine oxide 1 part by weight (manufactured by BASF, trade name Lucilin TPO), 1 part by weight of a silicone-based antifoaming agent as an antifoaming agent,
2 parts by weight of an acrylic leveling dispersant as an additive,
An ultraviolet curable white ink composition for printing was obtained at a mixing ratio of 50 parts by weight of a pigment containing titanium oxide as a main component.
(Formulation Example 2)

Formulation Example 3 15 parts by weight of a polycaprolactone-based urethane acrylate oligomer having a number average molecular weight of about 8,000 synthesized by a reaction of a polycaprolactone-based polyol, an organic polyisocyanate and hydroxyacrylate as an oligomer, and vinylcaprolactam as a photopolymerizable monomer 10 parts by weight
And 20 parts by weight of phenoxyethyl acrylate, 4 parts by weight of benzyl dimethyl ketal as a photopolymerization initiator (manufactured by Nippon Bagaigy Co., Ltd., trade name: Irgacure 651) and 2.
4.6-trimethylbenzoyldiphenylphosphine oxide 1 part by weight (manufactured by BASF, trade name Lucilin TPO), 1 part by weight of a silicone-based antifoaming agent as an antifoaming agent,
2 parts by weight of an acrylic leveling dispersant as an additive,
An ultraviolet curable white ink composition for printing was obtained at a mixing ratio of 50 parts by weight of a pigment containing titanium oxide as a main component.
(Formulation Example 3)

Formulation Example 4 As an oligomer, 15 parts by weight of a polycaprolactone-based urethane acrylate oligomer having a number average molecular weight of about 5,000 synthesized by a reaction of a polycaprolactone-based polyol, an organic polyisocyanate and hydroxyacrylate, and 15 parts by weight of a vinylcaprolactam as a photopolymerizable monomer 5 parts by weight
Phenoxyethyl acrylate, 20 parts by weight of phenoxyethyl acrylate, 5 parts by weight of isobornyl acrylate, 4 parts by weight of benzyldimethyl ketal as a photopolymerization initiator (trade name: Irgacure 651, manufactured by Nippon Bagaigie Co., Ltd.) and 2.4.6-trimethyl Benzoyldiphenylphosphine oxide 1
% By weight (manufactured by BASF, trade name Lucilin TPO), 1% by weight of a silicone-based antifoaming agent as an antifoaming agent, 2% by weight of an acrylic leveling dispersant as an additive, and titanium oxide as a main component as a pigment An ultraviolet curable white ink composition for printing was obtained at a blending ratio of 50 parts by weight of the pigment. (Formulation Example 6)

Formulation Example 5 22% by weight of a polycaprolactone-based urethane acrylate oligomer having a number average molecular weight of about 5,000 synthesized by a reaction of a polycaprolactone-based polyol, an organic polyisocyanate and hydroxyacrylate as an oligomer, and vinylcaprolactam as a photopolymerizable monomer 12 parts by weight
1. 26 parts by weight of phenoxyethyl acrylate, 4 parts by weight of benzyldimethyl ketal as a photopolymerization initiator (manufactured by Nippon Bagaigy Co., Ltd., trade name: Irgacure 651).
4.6-trimethylbenzoyldiphenylphosphine oxide 1 part by weight (manufactured by BASF, trade name Lucilin TPO), 1 part by weight of a silicone-based antifoaming agent as an antifoaming agent,
2 parts by weight of an acrylic leveling dispersant as an additive,
An ultraviolet-curable black ink composition for printing was obtained at a compounding ratio of 35 parts by weight of a pigment mainly composed of carbon iron oxide or the like as a pigment. (Formulation Example 11)

Formulation Example 6 22 parts by weight of a polycaprolactone-based urethane acrylate oligomer having a number average molecular weight of about 3,500 synthesized by a reaction of a polycaprolactone-based polyol, an organic polyisocyanate and hydroxyacrylate as an oligomer, and vinylcaprolactam as a photopolymerizable monomer 12 parts by weight
1. 26 parts by weight of phenoxyethyl acrylate, 4 parts by weight of benzyldimethyl ketal as a photopolymerization initiator (trade name: Irgacure 651, manufactured by Nippon Bagaigie Co., Ltd.)
4.6-trimethylbenzoyldiphenylphosphine oxide 1 part by weight (manufactured by BASF, trade name Lucilin TPO), 1 part by weight of a silicone-based antifoaming agent as an antifoaming agent,
2 parts by weight of an acrylic leveling dispersant as an additive,
An ultraviolet-curable black ink composition for printing was obtained at a compounding ratio of 35 parts by weight of a pigment mainly composed of carbon iron oxide or the like as a pigment. (Formulation Example 12)

Formulation Example 7 22 parts by weight of a polycaprolactone-based urethane acrylate oligomer having a number average molecular weight of about 8,000 synthesized by a reaction of a polycaprolactone-based polyol, an organic polyisocyanate and hydroxyacrylate as an oligomer, and vinylcaprolactam as a photopolymerizable monomer 15 parts by weight
And 23 parts by weight of phenoxyethyl acrylate, 4 parts by weight of benzyl dimethyl ketal as a photopolymerization initiator (Irgacure 651 manufactured by Nippon Bagaigie Co., Ltd.) and 2.
4.6-trimethylbenzoyldiphenylphosphine oxide 1 part by weight (manufactured by BASF, trade name Lucilin TPO), 1 part by weight of a silicone-based antifoaming agent as an antifoaming agent,
2 parts by weight of an acrylic leveling dispersant as an additive,
An ultraviolet-curable black ink composition for printing was obtained at a compounding ratio of 35 parts by weight of a pigment mainly composed of carbon iron oxide or the like as a pigment. (Formulation Example 13)

Formulation Example 8 22 parts by weight of a polycaprolactone-based urethane acrylate oligomer having a number average molecular weight of about 5,000 synthesized by the reaction of a polycaprolactone-based polyol, an organic polyisocyanate and hydroxyacrylate as an oligomer, and vinylcaprolactam as a photopolymerizable monomer 12 parts by weight
And 20 parts by weight of phenoxyethyl acrylate, 6 parts by weight of isobornyl acrylate, 4 parts by weight of benzyldimethyl ketal as a photopolymerization initiator (trade name Irgacure 651 manufactured by Nippon Bagaigie Co., Ltd.) and 2.4.6-trimethyl Benzoyldiphenylphosphine oxide 1
% By weight (manufactured by BASF, trade name: Luciline TPO) 1% by weight of a silicone-based antifoaming agent as an antifoaming agent, 2% by weight of an acrylic leveling dispersant as an additive, and carbon iron oxide as a pigment as a main component An ultraviolet curable black ink composition for printing was obtained at a blending ratio of 35 parts by weight of the pigment. (Formulation Example 16)

Formulation Example 9 25 parts by weight of a polycaprolactone-based urethane acrylate oligomer having a number average molecular weight of about 5,000 synthesized by a reaction of a polycaprolactone-based polyol, an organic polyisocyanate, and hydroxyacrylate as an oligomer, and vinylcaprolactam as a photopolymerizable monomer 15 parts by weight
And phenoxyethyl acrylate 30% by weight, benzyldimethyl ketal 5% by weight as a photopolymerization initiator (Irgacure 651 manufactured by Nippon Bagaigy Co., Ltd.), 1 part by weight of a silicone-based antifoaming agent as an antifoaming agent, additives As a result, a blue ink composition for ultraviolet curable printing was obtained with a blending ratio of 2 parts by weight of an acrylic leveling dispersant and 25 parts by weight of a pigment such as an organic extender or an organic coloring pigment as a pigment.
(Formulation Example 21)

A sample prepared by printing the white ink composition, the black ink composition, and the blue ink composition for ultraviolet-curing printing obtained in Formulation Examples 1 to 9 on a 0.5 mm-thick transparent polycarbonate substrate and curing the same was used. Table 2 shows the results of the adhesion test and the curability test. The test performed was a test 1 in which the cellophane tape was peeled off as Test 1, and the conveyor speed was 4 m / min, 6 m / mi.
The relationship between the number of times of overprinting and the relationship between the adhesiveness and the curability for four types of n, 8 m / min and 10 m / min is shown.
At any conveyor speed, good adhesiveness is obtained between 1 and 5 times of overprinting, and the film thickness can be increased by multiple times of overprinting. (Corresponding to the adhesive ◎ mark which is an item of the property test in Tables 1-1 to 1-5)

Further, as an adhesion test 2, a hot water resistance test (immersion in hot water at 40 ° C. for 24 hours) showed no peeling of the coating film. As a test 3 of adhesiveness, a thermal cycle test (cooling and heating was repeatedly performed in an atmosphere of −30 ° C. to + 80 ° C. with a cycle of 2 hours for 160 hours in an atmosphere of -30 ° C. to + 80 ° C.) was performed. I didn't see it at all. As a test 4 of the adhesiveness, a high-temperature and high-humidity test (leaving in an atmosphere of 60 ° C. and 90% RH for 200 hours) was performed. As a result, as shown in Table 2, the coating film did not peel off due to overprinting. . The printing and curing conditions for performing the adhesion test are as follows.

Printing plate used Polyester screen mesh # 305 Emulsion film thickness 8 μm Irradiation conditions Lamp height 110 mm Peak intensity 1.63 W / cm ² Integrated light intensity of lamp 0.77 J / cm ²

[0033]

[Table 2]

A pencil hardness test was performed on the printed and cured ultraviolet-curable white ink composition, black ink composition and blue ink composition of Formulation Examples 1 to 9 to find that the coating film of the present invention was obtained. Shows that the hardness according to the pencil scratch test shown in JIS K5400 is F, indicating that the coating film formed into a thick film by screen printing is sufficiently cured. (Corresponds to the ◎ mark of curability, which is an item of the property test in Tables 1-1 to 1-5)

In the impact resistance test, a 500 g weight was dropped from a height of 50 cm using a DuPont impact tester, and no cracks or cracks were observed.

Next, multicolor overprinting was carried out using the UV-curable ink compositions of the respective colors of white, black, red, blue, green, orange and overcoat obtained in Formulation Examples 1 to 9 and the like. Table 3 shows the results obtained by performing the peeling test on the scotch tape in order to confirm the curing and adhesion. Table 3
Indicates the case where the integrated light amount of the irradiation lamp is 1.05 J / cm ² ,
Excellent adhesiveness and curability were obtained in all processes, and all of the white, black, red, blue, green, and orange coating layers of the UV-curable printing ink composition were good without stickiness. Was.

[0037]

[Table 3]

Formulation Example 1, Formulation Example 2, Formulation Example 3, Formulation Example 6, Formulation Example 11, Formulation Example 12, Formulation Example 13, Formulation Example 16, Formulation Example 2
Each of the ink compositions (Formulation Examples 1 to 9) was printed on a 1 mm-thick polycarbonate substrate under the same conditions as those shown in Table 3.
The cured product was bent.

As bending conditions for checking the bending resistance, two bending processing conditions were set as shown in FIG. 1 and FIG. In Fig. 1, 45 ° is based on the plane printed and cured on the surface of a 1mm thick polycarbonate substrate.
The bending radius R1 of the corner surface of the substrate due to the bending is about 1.5 mm. Further, in FIG. 2, a 90 ° bending process is performed with reference to a plane printed and cured on the surface of a 1 mm-thick polycarbonate substrate, and the bending radius dimension R2 of the corner surface of the substrate due to the bending process is about 1.5 mm. . As a result of performing two bending tests of the 45 ° bending process and the 90 ° bending process, no abnormality was found in the coating portions of the ink compositions of Formulation Examples 1 to 9, and the film had excellent elongation characteristics. Therefore, it is also useful for punching after printing.

In terms of post-processability, each of the ink compositions of Formulation Examples 1 to 9 was printed and cured on a polycarbonate substrate having a thickness of 1 mm under the same conditions as shown in Table 3 and drawn.

As the aperture conditions, two aperture conditions were set as shown in FIGS. In Fig. 3, drawing is performed in the shape of a dish. The upper and lower molds are pressed and pressed without heating, the width of the inclined surface is 9mm, the height of the drawn surface is 3mm, and the inclination angle of the inclined surface is 18.4 °. And
(Aperture A) Also, in FIG. 4, the flat portion of the substrate is trapezoidally drawn, and the upper and lower molds are pressed down without heating, and the width of the inclined surfaces on both sides is reduced to 2 mm. The height is 2 mm and the inclination angle of each inclined surface is 45 °. (Aperture B)

The coating portions of the respective ink compositions in the above-mentioned Formulation Examples 1 to 9 and the like did not show any abnormalities such as cracks or peeling even after the post-processing under the drawing conditions of FIGS. 3 and 4. .

Further, the above-mentioned hot water resistance test, cooling / heating cycle test, and high-temperature / high-humidity test were performed on Formulation Examples 1 to 9 and the like in which the bending and drawing were performed. Table 1-1 and Table 1
-3, Formulation Example 1 (Formulation Example 1), Formulation Example 5 (Formulation Example 11), and Formulation Example 9 (Formulation Example) indicated by ◎ in the post-processability of Table 1-5.
21) was raised. Formulation Example 2 (Formulation Example 2), Formulation Example 3 (Formulation Example 3), Formulation Example 4 (Formulation Example 6), Formulation Example 6
In Formulation Example 12, Formulation Example 7 (Formulation Example 13), and Formulation Example 8 (Formulation Example 16), in the drawing process, in the setting of the condition of the drawing B, 1 to 2 sheets of each 10 samples Some cracks were very small. (Table 1-1, Table 1
-2, indicated by a circle B in Table B in Tables 1-3 and 1-4)

In the drawing process of the drawing B, the upper and lower molds were drawn while being heated, and as a result of each of the above Formulation Examples 2, 3, 4, 6, 7, and 8, which were marked with a circle. No cracks occurred.

Also, Formulation Example 4 in Table 1-1 and Table 1-2
5, 7, 8, 9, and 10 show comparative examples of white ink. In the above-mentioned example 4 (comparative example), 15 parts by weight of a polyester-based urethane acrylate oligomer having a number average molecular weight of about 3,500 was used. Although it is compounded as an oligomer, although the adhesiveness and curability by overprinting are satisfied to some extent (curability ○, adhesiveness ○), peeling of the coating film is observed at 90 ° bending, and drawing is performed. Cracking and peeling are recognized by the drawing B of the processing. (Bending 90 ° in Table 1-1 ×, Aperture B ×)

Formulation Example 5 (Comparative Formulation Example) and Formulation Example 7
In Comparative Formulation Example, similarly to Formulation Example 4 (Comparative Formulation Example), peeling of the coating film was observed in the post-processability especially at the bending angle of 90 °, and the coating film was cracked even in the drawing B of the drawing process. Alternatively, peeling was observed. (Bending 90 ° × in Table 1-1 and Table 1-2, Aperture B ×)

In Formulation Example 8 (Comparative Formulation Example),
In the overprint printing, when performing overprinting on 6 or more layers, a phenomenon of delamination is observed in the coating film, and cracks and peeling are observed in the coating film at bending of 45 ° and bending of 90 ° in the post-processability, Also in the drawing A and the drawing B of the drawing process, peeling was observed in the coating film portion. (Adhesion of Table 1-1 △, all about post-processability ×)

In Formulation Example 9 (Comparative Formulation Example),
Although no abnormality was observed in the coating film portion during the post-processing, in particular, as a result of a cooling / heating cycle test, fine cracks were found at the corners of the substrate due to bending and drawing. (All of the post-processing properties in Table 1-2 are △)

In Formulation Example 10 (Comparative Formulation Example), peeling of the coating film from the substrate was observed in the adhesiveness, delamination between the coating films was also observed, and overprinting was also performed on the curable surface. Sometimes stickiness was observed. (Table 1
-2 Adhesion ×, curability △, and post-processability are all ×)

Formulations 14 and 1 in Tables 1-3 and 1-4
5, 17, 18, 19 and 20 show comparative examples of the black ink, respectively. The above-mentioned formulation examples 14 (comparative formulation examples), 15 (comparative formulation examples) and 17 (comparative formulation examples) Shows almost the same characteristics in the characteristic test. Although the adhesiveness and the curability during overprinting are almost satisfactory without stickiness of each coating layer (curable ○, adhesive ○), the post-processability At a bending of 90 ° in the bending process, fine cracks were observed in the coating film portion, and in the drawing B in the drawing process, cracks and partial peeling were also observed in the coating film portion. (Tables 1-3 and 1
-4 bending 90 ° ×, aperture B ×)

In Formulation Example 18 (Comparative Formulation Example), when overprinting is performed for five or more layers, delamination tends to occur between the coating films, and peeling of the coating film is observed over the entire post-processability. Can be (Adhesion of Table 1-4 △, all about post-processability ×)

In Formulation Example 19 (Comparative Formulation Example), there was no stickiness in the adhesiveness and curability, and the adhesion between the coating layers was almost good (curability ，, adhesion ○), and post-processability was also high. No cracks or other phenomena were observed in the coating film, but fine cracks were observed at the bent parts and corners of the board due to bending and drawing, especially when the thermal cycle test and the high-temperature and high-humidity test were performed. . (All in Table 1-4 for post-processability)

In Formulation Example 20 (Comparative Formulation Example), with regard to the curability, stickiness was observed at the time of overprinting, and peeling of the coating film portion from the substrate was also observed on the adhesive surface. Competitor delamination was also observed. (Curability in Table 1-4, Adhesion ×, Post-workability are all ×)

[0054]

As described above, the polyurethane acrylate oligomer is a polycaprolactone-based urethane acrylate oligomer as the ultraviolet-curable printing ink composition of the present invention, and contains vinylcaprolactam and phenoxyethyl acrylate as essential components, so that it adheres to the material. It excels in properties and flexibility of the cured film, can prevent delamination of the cured film after overprinting in the printing operation, and can solve the problems of cracking and peeling due to post-processing (drawing and bending). .

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part showing a reference example of a 45 ° bending process of the present invention.

FIG. 2 is a sectional view of a main part showing a reference example of 90 ° bending processing of the present invention.

FIGS. 3A and 3B are a perspective view of a main part and a sectional view of the main part showing a reference example of drawing according to the present invention.

FIGS. 4A and 4B are a cutaway perspective view of a main part and a cross-sectional view of a main part showing a reference example of drawing according to the present invention.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-4-323275 (JP, A) JP-A-3-220218 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C09D 11/00-11/20

Claims (1)

(57) [Claims] 1. An ultraviolet-curable printing ink composition, wherein the polyurethane acrylate oligomer is a polycaprolactone-based urethane acrylate oligomer, and contains vinylcaprolactam and phenoxyethyl acrylate as essential components.