KR20210115357A - Solvent-free UV-curable black ink composition applicable to pad printing process - Google Patents

Abstract

The present invention relates to a solvent-free UV-curable black ink composition, a method for forming a bezel pattern using the same, a bezel pattern manufactured thereby, and a display substrate including the same. The black ink composition comprises: (A) a urethane acrylate oligomer; (B) a reactive monomer that is a mixture of two or more reactive monomers; (C) a photoreaction initiator; (D) black pigment; and (E) an additive. The UV-curable black ink composition according to the present invention has excellent light-shielding properties even with a thin thickness, thereby being capable of forming a pattern on a substrate only through UV curing after pad printing, wherein the pattern exhibits excellent light-shielding effect with a desired thin thickness and outstanding adhesion.

Description

Solvent-free UV-curable black ink composition applicable to pad printing process}

The present invention relates to a solvent-free UV curable black ink composition applicable to a pad printing process, a method for forming a bezel pattern using the same, a bezel pattern manufactured according to the method, and a display substrate including the same.

Recently, the display market is evolving into flexible products, curved products, and even foldable products. Most of these display devices require a bezel pattern that imparts color while the non-display area pattern of the panel is not visually recognized.

A technique of patterning a bezel pattern by a conventional inkjet or spray method has been attempted. However, if thermosetting type ink is used after pattern implementation, high temperature is required for curing or space for curing chamber is required in many cases. It is difficult to do, and in particular, when applied to a curved substrate, there may be difficulties in maintaining the shape, such as flowing down.

On the other hand, UV curable inks, which take a relatively short time to form a pattern due to a short curing time, have also been developed. However, the existing UV curable inks have low light-shielding properties, which causes problems in pattern recognition, and has a problem in that the adhesive strength is lower than that of thermosetting inks. .

Accordingly, there have been attempts to perform pad printing with an ultraviolet curable black ink composition.

For example, Korean Patent Application Laid-Open No. 10-2012-0080878 relates to a conductive ink composition, comprising at least one functional group from the group consisting of a hydroxyl group, a chloride group, a phenyl group, a butyral group, an acetal group, an acetate group, and a carboxyl group. binder resin; fine metal powder; hardener; and a conductive ink composition comprising a solvent and a method for preparing the same. The composition is remarkably excellent in pad printing process efficiency and productivity.

In addition, Korean Patent Laid-Open No. 10-2019-0071597 relates to an ultraviolet curable black ink composition for a foldable display, comprising: a black pigment; dispersant; epoxy compounds; oxetane compounds; light diffusing agent; photoinitiator; and an ultraviolet curable ink composition for forming a black bezel pattern including an organic solvent.

However, the existing composition is still in need of improvement in pad printing processability, light-shielding properties and adhesiveness.

US 10-2012-0080878 A US 10-2015-0051391 A US 10-2016-0147535 A US 10-2016-0046723 A US 10-2019-0071597 A

It is an object of the present invention to provide a solvent-free UV curable black ink composition that has excellent adhesion to a substrate, good scratch resistance, and excellent light blocking effect, which can be applied to a pad printing process for forming a bezel pattern for a display substrate.

The present invention provides a solvent-free ultraviolet curable black ink composition comprising the following components (A) to (E):

(A) 10 to 50% by weight of a urethane acrylate oligomer;

(B) 10 to 50% by weight of a reactive monomer that is a mixture of two or more reactive monomers;

(C) 0.1 to 10% by weight of a photoreaction initiator;

(D) 1 to 50% by weight of a black pigment; and

(E) 1 to 50% by weight of an additive.

The composition may be for a pad printing process.

The (A) urethane acrylate oligomer is a polyether polyol or polyester polyol and an aliphatic isocyanate, cyclic aliphatic isocyanate or aromatic isocyanate compound having two or more isocyanate groups in one molecule After reacting some isocyanate functional groups in the oligomer, the rest It may be formed by addition-reacting an unreacted isocyanate group with an acrylate monomer containing a hydroxyl group.

The reactive monomer (B) may be an acrylate monomer having one, two, or three or more functional groups.

The reactive monomer (B) may be a mixture of an acrylate monomer having one functional group and an acrylate monomer having two or three or more functional groups.

The content of the acrylate monomer having one functional group is preferably greater than the content of the acrylate monomer having two or three or more functional groups.

The ratio between the content of the acrylate monomer having one functional group and the content of the acrylate monomer having two or three or more functional groups is preferably 6 to 9: 1 to 4.

The (C) photoreaction initiator may be at least one selected from the group consisting of alpha-hydroxy-ketone, alpha-amino-ketone, benzyl dimethyl ketal, phosphine oxide, metallocene, and oxanthone. .

The (D) black pigment is selected from the group consisting of organic pigments, carbon black, inorganic black pigments, and mixtures thereof, and may have an average particle diameter in the range of 0.5 to 50 μm.

The (E) additive may be at least one dispersant selected from the group consisting of anionic, cationic, electrically neutral, nonionic, polyurethane, and polyacrylate.

In addition, the present invention includes the steps of pad-printing the black ink composition of the present invention on a substrate to form a bezel pattern; And it provides a method of forming a bezel pattern comprising the step of curing by irradiating ultraviolet rays to the bezel pattern.

The bezel pattern may have a thickness of 5.0 to 10.0 μm.

In addition, the present invention provides a bezel pattern manufactured by using the method for forming a bezel pattern of the present invention.

In addition, the present invention provides a display substrate including the bezel pattern of the present invention.

The ultraviolet curable black ink composition according to the present invention has excellent adhesion and coating properties to the substrate. In addition, the bezel pattern formed from the ultraviolet curable ink composition of the present invention has excellent pad processability and, at the same time, excellent physical properties such as light-shielding property, hardness, and adhesion.

Since the ultraviolet curable black ink composition of the present invention is a solvent-free type and does not use a solvent, it is possible to prevent environmental pollution due to volatilization and product contamination due to outgas.

Hereinafter, the solvent-free ultraviolet curable black ink composition prepared according to the present invention, a method of forming a bezel pattern using the same, a bezel pattern prepared according to the method, and a display substrate including the same will be described in detail according to embodiments. However, the present invention is not limited by this embodiment.

The composition of the present invention relates to a solvent-free ultraviolet curable black ink composition comprising the following components (A) to (E):

(A) 10 to 50% by weight of a urethane acrylate oligomer;

(B) 10 to 50% by weight of a reactive monomer that is a mixture of two or more reactive monomers;

(C) 0.1 to 10% by weight of a photoreaction initiator;

(D) 1 to 50% by weight of a black pigment; and

(E) 1 to 50% by weight of an additive.

[(A) component]

(A) The urethane acrylate oligomer is the most important component for determining the properties of UV-cured products. It is a compound of polyether polyol or polyester polyol and aliphatic isocyanate, cyclic aliphatic isocyanate or aromatic isocyanate compound having two or more isocyanate groups in one molecule. It may be formed by reacting some isocyanate functional groups in the oligomer, and then adding the remaining unreacted isocyanate groups with an acrylate monomer containing a hydroxyl group.

The polyether-based polyol or polyester-based polyol is a polyether-based polyol or polyester-based polyol having a functional group of 1,2 to 3, a hydroxyl value of 25 to 75 mg KOH/g, and a molecular weight of 1500 to 3100 g/mol. Can be used.

The polyether-based polyol is polyethylene glycol, polypropylene glycol, polybutylene glycol, polypentylene glycol, polytetramethylene glycol, polyhexamethylene glycol, polyheptamethylene glycol, polydecamethylene glycol and a group consisting of polyether-based diols. It may be at least one selected from

The polyester-based polyol is polyethylene adipate diol, polybutylene adipate diol, polyhexamethylene isophthalate adipate diol, 3-methyl-1,5-pentaneisophthalate diol, 3-methyl-1,5-pentane tere. phthalate diol, and a polycondensate of 1,6-hexanediol and dimer acid.

The oligomer of an aliphatic isocyanate, cyclic aliphatic isocyanate or aromatic isocyanate compound having two or more isocyanate groups in one molecule is, for example, isophorone diisocyanate, dicyclohexylmethane-4,4-diisocyanate, hexamethylene diisocyanate, 2,2-dimethylpentane diisocyanate, 2,2,4-trimethyl hexane diisocyanate, butene diisocyanate, 1,3-butadiene-1,4-diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, 1 aliphatic isocyanate-based compounds including ,6,11-undecatriisocyanate and the like; and bis(isocyanatoethyl)benzene, bis(isocyanatopropyl)benzene, bis(isocyanatobutyl)benzene, bis(isocyanatomethyl)naphthalene, bis(isocyanatomethyl)di Phenyl ether, phenylene diisocyanate, ethylphenylene diisocyanate, isopropylphenylene diisocyanate, dimethylphenylene diisocyanate, diethylphenylene diisocyanate, diisopropylphenylene diisocyanate, trimethylbenzene triisocyanate, benzene triisocyanate, biphenyl diisocyanate, 3,3-dimethoxybiphenyl-4,4-diisocyanate, hexahydrobenzenediisocyanate, hexahydrodiphenylmethane-4,4-diisocyanate, and mixtures thereof.

The hydroxyl group-containing acrylate monomer is 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate , 6-hydroxyhexyl (meth) acrylate, 1,4-cyclohexanedimethanol mono (meth) acrylate, 1-chloro-2-hydroxypropyl (meth) acrylate, diethylene glycol mono (meth) acrylic rate, 1,6-hexanediol mono (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, and the like.

The urethane acrylate oligomer is preferably used in an amount of 10 to 50% by weight based on 100% by weight of the black ink composition. If the content of the urethane acrylate oligomer is less than 10% by weight, the pad printing quality may deteriorate, and the same phenomenon may occur when it exceeds 50% by weight .

[(B) component]

The composition of the present invention comprises a reactive monomer that is a mixture of two or more reactive monomers.

The reactive monomer is an acrylate monomer capable of UV curing, and may be an acrylate monomer having one, two, or three or more functional groups.

As the acrylate monomer having one functional group, caprolactone acrylate, ortho-phenylphenol ethoxy acrylate, lauryl acrylate, isodecyl acrylate, tetrahydro furfuryl acrylate, 2-hydroxyethyl acrylate, At least one acrylate monomer having one functional group selected from the group consisting of 4-hydroxybutyl acrylate, 2-hydroxyethyl methacrylate and ethoxy ethoxy ethyl acrylate may be used, preferably iso It may be decyl acrylate, but is not limited thereto.

The acrylate monomer having the two functional groups is used for the purpose of controlling the viscosity of the ink and increasing the reactivity. 1,6-hexanediol diacrylate, 1,10-decanediol diacrylate, and tripropylene glycol diacrylic At least one acrylate monomer having two functional groups selected from the group consisting of lactate, dipropylene glycol diacrylate, triethylene glycol diacrylate and triclodecane dimethanol diacrylate may be used, but is not limited thereto. .

Trimethylolpropane triacrylate, trimethylolpropane (ethylene oxide) modified triacrylate, pentaerythritol triacrylate, trimethylolpropane (propylene oxide) modified triacrylate and tris ( 2-hydroxyethyl) one or more acrylate monomers having three or more functional groups selected from the group consisting of isocyanurate triacrylate may be used, preferably pentaerythritol triacrylate, but limited thereto it doesn't happen

The reactive monomer is preferably used in an amount of 10 to 50% by weight based on 100% by weight of the black ink composition. If the content of the reactive monomer is less than 10% by weight, pad printing quality may be deteriorated, and even if it exceeds 50% by weight, the same result may be exhibited.

Preferably, the reactive monomer may be a mixture of an acrylate monomer having one functional group and an acrylate monomer having two or three or more functional groups.

More preferably, the content of the acrylate monomer having one functional group may be greater than the content of the acrylate monomer having two or three or more functional groups. The ratio of the content of the acrylate monomer having one functional group to the content of the acrylate monomer having two or more functional groups is 6 to 9: 1 to 4, preferably 7 to 8: 2 to 3 have.

In one embodiment of the present invention, when the content of the acrylate monomer having one functional group is greater than the content of the acrylate monomer having two or three or more functional groups, the pad processability is excellent (see Table 1).

[(C) component]

The (C) photoreaction initiator functions to initiate a photopolymerization reaction by absorbing the energy of ultraviolet rays to generate radicals or cations, and has a great influence on the polymerization rate, curing depth, and the like.

As the photoreaction initiator, a polymerization initiator that is polymerized by absorbing energy from an ultraviolet light source can be generally used. Preferably, alpha-hydroxy-ketone-based, alpha-amino-ketone-based, benzyl dimethyl ketal-based, phosphine oxide-based, metallocene-based, oxanthone-based and the like may be used, and more preferably, alpha-amino-ketone-based. It can be used alone or in combination among the phosphine oxide system and the phosphine oxide system.

The photoreaction initiator is preferably used in an amount of 0.1 to 10% by weight based on 100% by weight of the black ink composition. If the content of the photoreaction initiator is less than 0.1 wt%, the photoreaction efficiency may be reduced, and if it exceeds 10 wt%, the photoreaction initiator may be used in excess and compatibility of the composition may be deteriorated.

[(D) component]

The (D) black pigment may be selected from the group consisting of organic pigments, carbon black, inorganic black, and mixtures thereof.

The organic pigment is phthalocyanine-based, azo-based, azomethine azo-based, azomethine-based, anthraquinone-based, perinone/perylene-based, indigo/thioindigo-based, dioxazine-based, quinacridone-based, isoindoline-based, isoindoli Non-based, diketopyrrolopyrrole-based, quinophthalone-based, indanthrene-based pigments, or the like, may be carbon black pigments.

In addition, the inorganic pigment may be an extender filler, a titanium oxide-based pigment, an iron oxide-based pigment, a spinel pigment, or the like.

Double organic pigments can be used alone or mixed to give black or a color close to black, or carbon black or black inorganic pigment can be used to represent black color.

In one embodiment of the present invention, carbon black was used.

The black pigment may have an average particle diameter in the range of 0.5 to 50 um, preferably in the range of 10 to 40 um.

The black pigment is preferably used in an amount of 1 to 50% by weight based on 100% by weight of the black ink composition. If the content of the black pigment is less than 1% by weight, light-shielding properties may be deteriorated, and if it is more than 50% by weight, the compatibility of the composition may be deteriorated due to excessive use of the black pigment.

[(E) component]

The additive (E) may be a dispersant used for dispersing and stabilizing the pigment of the ink composition.

The dispersant can be selected from a low molecular dispersant, a polymer dispersant, and a dispersant for water-based paints according to the characteristics of the pigment.

Anionic, cationic, electrically neutral, nonionic, etc. can be used as the low molecular dispersant, and as the polymer dispersant, polyurethane, polyacrylate, wetting and dispersing agents for water-based paints, etc. can be used. Among them, the pigment to be used and a suitable dispersant are selected and used.

In one embodiment of the present invention, the polymer dispersant was added in an amount adjusted according to the pigment concentration, either alone or by mixing.

The additive is preferably used in an amount of 1 to 50% by weight based on 100% by weight of the black ink composition. If the content of the additive is less than 1% by weight, the pigment dispersion and stabilization effect may not be sufficient, so light-shielding properties may be deteriorated. .

Since the ultraviolet curable black ink composition of the present invention is a solvent-free type and does not use a solvent, it is possible to prevent environmental pollution due to volatilization and product contamination due to outgas.

The ultraviolet curable black ink composition has excellent adhesion and coating properties to the substrate. In addition, the bezel pattern formed according to the present invention with the ultraviolet curable ink composition has excellent adhesion to the substrate. It can be seen that the solvent-free UV-curable black ink composition according to the present invention has excellent pad processability and excellent physical properties such as light-shielding property, hardness, and adhesion, as shown in a test to be described later (see Table 1).

The solvent-free UV-curable black ink composition according to the present invention spreads within a short time immediately after pad printing, exhibiting excellent coating film properties, and exhibiting excellent adhesive properties when cured. Therefore, when applying the solvent-free UV-curable black ink composition, it is preferable to install an UV lamp immediately behind the pad part to enable curing at the same time as pad printing.

The method for preparing the ultraviolet curable black ink composition of the present invention is as follows:

Add urethane acrylate oligomer (A), reactive monomer (B), black pigment (D) and additive (E) to a stirrer, and use a dispersion impeller at a temperature of 15 to 50° C. and a humidity of 60% or less at 1000 rpm or more After stirring at a uniform speed, the agitated material is dispersed using a mill disperser. The photoreaction initiator (C) is added to the dispersed mill base and stirred at a uniform speed of 1000 rpm or more using a dispersion impeller at a temperature of 15 to 50° C. and a humidity of 60% or less. If the reaction temperature is less than 15 ℃, the viscosity of the oligomer (a) rises, causing a problem in the process, and when the temperature exceeds 50 ℃, the photoreaction initiator (C) forms a radical to cause a curing reaction. When the reaction humidity exceeds 60%, the resulting composition generates bubbles during the subsequent printing process, and there is a problem in that a side reaction occurs in which unreacted materials react with moisture in the air. Also, if the stirring speed is less than 1,000 rpm Mixing may not work well.

In addition, the present invention includes the steps of pad-printing the black ink composition on a substrate to form a bezel pattern; And it provides a method of forming a bezel pattern comprising the step of curing by irradiating ultraviolet rays to the bezel pattern.

The ink composition of the present invention can be applied to the pad printing process. Pad printing is a printing technique in which a printed pattern is transferred through a soft pad such as silicone to perform printing on an object to be printed. It is a printing technique in which the transferred ink is transferred by contacting the printing object from the top of the printing object. Pad printing has advantages in that the printing process is simple, images can be easily printed on a curved 3-D surface, the printing speed is fast, and ink is used efficiently.

The bezel pattern may have a thickness of 5.0 to 10.0 μm. In one embodiment of the present invention, when the bezel pattern was 5.0 ㎛ thick, it was confirmed that the pad fairness and physical properties such as light blocking properties, hardness, adhesion, etc. were very excellent.

The UV curable black ink composition may have a curing dose of 1 to 10,000 mJ/cm 2 , preferably 3,000 to 5,000 mJ/cm 2 .

The ultraviolet curable black ink composition may be cured by absorbing radiation in a wavelength range of 250 nm to 450 nm, preferably 360 nm to 410 nm.

In addition, the present invention provides a bezel pattern manufactured by using the method for forming the bezel pattern.

The bezel pattern may have a surface hardness of 2H or more and an adhesive force of 5B or more.

In addition, the present invention provides a display substrate including the bezel pattern.

The display substrate includes a plasma display panel (PDP), a light emitting diode (LED), an organic light emitting diode (OLED), a liquid crystal display (LCD), and a thin film transistor. It may be used in any one of a liquid crystal display device (Thin Film Transistor-Liquid Crystal Display, LCD-TFT) and a cathode ray tube (CRT).

The present invention will be described in more detail through specific examples. The described embodiments are merely illustrative, and the scope of the present invention is not limited thereto. Contents not described herein will be omitted from descriptions that can be technically inferred by those skilled in the art.

<Preparation of UV-curable black ink composition>

Specific specifications of the components used in Examples and Comparative Examples are as follows.

1) Urethane acrylate oligomer: self-synthesis

2) Reactive monomer A: isodecyl acrylate

3) Reactive monomer B: pentaerythritol triacrylate

4) Photoreaction initiator A: alpha-amino-ketone type - I-907 BASF Corporation

5) Photoinitiator B: Phosphine Oxide type I-819 BASF Corporation

6) Black pigment: Special-BK-4A (carbon black, 25㎛) DEGUSSA

7) Additive A: BYK-410 (BYK Co., Ltd.)

8) Additive B: BYK-168 (BYK Co., Ltd.)

<Synthesis Example 1>

10 parts by weight of 2-butyl-2-ethyl-1,3-propanediol, poly(ethylene-co-butylene)diol [manufactured by Nippon Procurement Co., Ltd.] in a clean 4L glass reactor equipped with a stirrer, thermometer and cooling jacket , trade name: GI-2000, molecular weight about 2,500)] 65 parts by weight, 45 parts by weight of isobornyl acrylate as a diluent, and 25 parts by weight of isophorone diisocyanate were added, stirred well, and the temperature of the reactor was raised to 85° C., and then dibutyltin 0.02 parts by weight of dilaurate was added and reacted for 1 hour and 30 minutes.

Here, while maintaining the temperature at 85° C., 10 parts by weight of 2-hydroxyethyl (meth)acrylate and 0.2 parts by weight of itaconic acid were added, and the reaction was further allowed to proceed for 1 hour. After confirming that the isocyanate group disappeared by measuring the reactant by IR, the reaction was terminated to obtain a urethane acrylate oligomer compound having an ethylenically unsaturated double bond.

<Example 1>

40.0% by weight of the urethane acrylate oligomer compound obtained in Synthesis Example 1, 7.0% by weight of reactive monomer A, 3.0% by weight of reactive monomer B, 2.5% by weight of photoinitiator A, 2.5% by weight of photoinitiator B, 5.0% by weight of additive A , additive B 20.0% by weight, and black pigment 20.0% by weight were mixed well at room temperature to obtain an ultraviolet curable black ink composition.

<Example 2>

In Example 1, 45.0% by weight of the urethane acrylate oligomer compound, 8.0% by weight of reactive monomer A, and 2.0% by weight of reactive monomer B were used, and in the same formulation and method as in Example 1, except that additive A was not used. A curable black ink composition was obtained.

<Example 3>

An ultraviolet curable black ink composition was obtained in the same formulation and manner as in Example 1, except that 5.0 wt% of the photoreaction initiator A was used in Example 1 and the photoreaction initiator B was not used.

<Example 4>

An ultraviolet curable black ink composition was obtained in the same formulation and manner as in Example 1, except that in Example 1, photoreaction initiator A was not used and 5.0 wt% of photoreaction initiator B was used.

<Comparative Example 1>

An ultraviolet curable black ink composition was obtained in the same formulation and manner as in Example 1, except that 50.0 wt% of the urethane acrylate oligomer compound and the reactive monomer A and the reactive monomer B were not used in Example 1.

<Comparative Example 2>

An ultraviolet curable black ink composition was obtained in the same formulation and manner as in Example 1, except that 10.0 wt% of the reactive monomer A was used in Example 1 and that the reactive monomer B was not used.

<Comparative Example 3>

An ultraviolet curable black ink composition was obtained in the same formulation and manner as in Example 1, except that in Example 1, reactive monomer A was not used and 10.0 wt% of reactive monomer B was used.

<Comparative Example 4>

An ultraviolet curable black ink composition was obtained in the same formulation and manner as in Example 1, except that 5.0 wt% of reactive monomer A and 5.0 wt% of reactive monomer B were used in Example 1.

<Test Example> Evaluation of physical properties of black ink composition

1) Check corrosion plate and check PICK UP

After filling the ink cup of the pad ink corrosion plate with the ink prepared in Examples and Comparative Examples, the pad printing process was performed. As a result of the process, the ink filled in the ink cup of the etching plate is spaced apart from the recess of the pad. At this time, the presence or absence of ink residues on the etched plate except for the concave portion of the pad was checked. In addition, it was checked whether the desired shape and amount were accurately spaced apart from the concave portion of the pad, and the results are shown in Table 1 below.

2) Is there any residue on the pad?

After the ink spaced apart from the concave portion of the pad was applied to the substrate, it was checked whether ink residues remained on the pad. If the ink is completely separated from the base material, no ink residue remains on the pad, and if the thickness to be formed is too thick or if the ink is not completely separated from the pad due to the viscosity and TI properties of the ink, residual ink remains on the pad, This is because a uniform thickness may not be formed when pad printing is performed through the process.

3) optical density

A film was prepared by curing the ink applied to the substrate by irradiating ultraviolet rays. The optical density of the film was measured. The optical density can be used as an index indicating the light-shielding property of the film. During evaluation, the thickness of the film was adjusted to 5 μm.

4) Pencil hardness test

After fixing a pencil at a load of 0.5 kg and an angle of 45°, the surface of the film was scratched by pencil hardness to evaluate whether it was scratched with the naked eye.

5) Crosscut test

After pattern printing using the inks of Examples and Comparative Examples, a cross-cut test was performed to evaluate adhesion to the substrate after UV curing, and the results were evaluated as 0B to 5B. (Standard: ASTM D3002, D3359)

The results of Examples and Comparative Examples are summarized in Table 1 below.

As shown in the table above, urethane acrylate oligomer 10 to 50% by weight; 10 to 50% by weight of reactive monomer; 0.1 to 10% by weight of a photoreaction initiator; 1 to 50% by weight of black pigment; And the ink composition of the present invention comprising 1 to 50% by weight of the additive was excellent in physical properties such as pad processability, light-shielding property, hardness, and adhesion. In particular, when the content of the reactive monomer A (an acrylate monomer having one functional group) is greater than the content of the reactive monomer B (an acrylate monomer having three functional groups) (Examples 1 to 4), the content of the reactive monomer A and the reactive monomer It was confirmed that the pad fairness was excellent compared to the case where the content of B was the same (Comparative Example 4).

Claims (13)

A solvent-free UV curable black ink composition comprising the following components (A) to (E):
(A) 10 to 50% by weight of a urethane acrylate oligomer;
(B) 10 to 50% by weight of a reactive monomer;
(C) 0.1 to 10% by weight of a photoreaction initiator;
(D) 1 to 50% by weight of a black pigment; and
(E) 1 to 50% by weight of an additive. According to claim 1,
The composition is a composition for a pad printing process. According to claim 1,
The (A) urethane acrylate oligomer,
A polyether polyol or polyester polyol is reacted with some isocyanate functional groups in an oligomer of an aliphatic isocyanate, cyclic aliphatic isocyanate, or aromatic isocyanate compound having two or more isocyanate groups in one molecule, and then the remaining unreacted isocyanate groups are reacted with an acrylate monomer containing a hydroxyl group. A composition formed by addition reaction. According to claim 1,
The (B) reactive monomer is an acrylate monomer having one, two, or three or more functional groups. According to claim 1,
The (B) reactive monomer is a composition that is a mixture of an acrylate monomer having one functional group and an acrylate monomer having two or three or more functional groups. 6. The method of claim 5,
The content of the acrylate monomer having one functional group is greater than the content of the acrylate monomer having two or three or more functional groups. According to claim 1,
The (C) photoreaction initiator is at least one selected from the group consisting of alpha-hydroxy-ketone, alpha-amino-ketone, benzyl dimethyl ketal, phosphine oxide, metallocene, and oxanthone. composition. According to claim 1,
The (D) black pigment is selected from the group consisting of organic pigments, carbon black, inorganic black pigments, and mixtures thereof, and the average particle diameter is in the range of 0.5 to 50 um. According to claim 1,
The (E) additive is one or more dispersants selected from the group consisting of anionic, cationic, electrically neutral, nonionic, polyurethane-based and polyacrylate-based composition. forming a bezel pattern by pad-printing the black ink composition of claim 1 on a substrate; and
A method of forming a bezel pattern comprising the step of curing the bezel pattern by irradiating ultraviolet rays. 11. The method of claim 10,
The thickness of the bezel pattern is 5.0 to 10.0㎛ method of forming a bezel pattern. A bezel pattern manufactured using the method for forming the bezel pattern of claim 10 . A display substrate comprising the bezel pattern of claim 12 .