UV-curable ink composition, method for producing bezel pattern of display substrate using same, and bezel pattern produced thereby

Abstract

The present invention relates to a UV-curable ink composition, a method for producing a bezel pattern of a display substrate using same, and a bezel pattern produced thereby, the UV-curable ink composition comprising a colorant, an epoxy compound, an oxetane compound, a photopolymerization initiator, and a surfactant comprising a polar functional group, wherein the content ratio of the epoxy compound to the oxetane compound is 1:0.5-1:6, an adhesion to a glass substrate after curing is 4B or higher according to the ASTM D3359 standard, a contact angle to the glass substrate is less than 10, and an adhesion with a substrate coated with an adhesive layer after curing is 100-5,000 gf/25 mm.

Claims

1. A UV-curable ink composition for forming a bezel pattern comprising a colorant, an epoxy compound, an oxetane compound, a photopolymerization initiator, a surfactant comprising a polar functional group, and an adhesion promoter, wherein a content ratio of the epoxy compound to the oxetane compound is 1:2.58 to 1:6, an adhesive force to a glass base material after curing is 4B or higher according to the ASTM D3359 standard, a contact angle with respect to a glass base material is less than 10, and an upper portion attaching force after curing is 100 to 5,000 gf/25 mm, and wherein the adhesion promoter is one or more silane-based compounds selected from the group consisting of amino silane-based compounds, alkoxy silane-based compounds, epoxy silane-based compounds, aminophenyl silane-based compounds, amino silane-based compounds, mercapto silane-based compounds, and vinyl silane-based compounds.

2. The UV-curable ink composition of claim 1, further comprising one or more selected from the group consisting of a colorant, and a photosensitizer.

3. The UV-curable composition of claim 1, wherein the surfactant comprising the polar functional group comprises one functional group selected from the group consisting of a carboxyl group, a hydroxy group, a phosphoric acid group, and a sulfonic acid group.

4. The UV-curable composition of claim 3, wherein the surfactant is a polymer-type or oligomer-type fluorine-based surfactant, and the surfactant is not dissolved in a solvent having a solubility parameter value of less than 15 (MPa).sup.0.5, is not dissolved in an amount of 0.1 wt % or more in a solvent having a solubility parameter value of 45 (MPa).sup.0.5 or more, and is dissolved in an amount of 1 wt % or more in a solvent having a solubility parameter value of 15 to 21 (MPa).sup.0.5 and shows no phase separation.

5. The UV-curable composition of claim 4, wherein the solvent having a solubility parameter value of less than 15 (MPa).sup.0.5 is hexane, the solvent having a solubility parameter value of 45 (MPa).sup.0.5 or more is water, and the solvent having a solubility parameter value of 15 to 21 (MPa).sup.0.5 is propylene glycol monomethyl ether (PGME) or toluene.

6. The UV-curable composition of claim 3, wherein the surfactant is a surfactant comprising a reactive hydroxy group as a silicone-based additive.

7. The UV-curable composition of claim 3, wherein the surfactant is a non-silicone-based surfactant which does not comprise a fluorine component.

8. The UV-curable composition of claim 3, wherein the surfactant comprising the polar functional group is comprised in an amount of 0.1 to 5.0 wt % with respect to a total weight of the UV-curable ink composition.

9. The UV-curable composition of claim 1, wherein the oxetane compound comprises an oxetane compound having one oxetane ring and an oxetane compound having two oxetane rings.

10. The UV-curable composition of claim 9, wherein a content ratio of the oxetane compound having one oxetane ring to the oxetane compound having two oxetane rings is 1:16 to 1:3.

11. The UV-curable composition of claim 1, wherein a content of the epoxy compound is 5 to 50 wt % with respect to the total weight of the UV-curable ink composition.

12. The UV-curable composition of claim 1, wherein a content of the oxetane compound is 15 to 75 wt % with respect to the total weight of the UV-curable ink composition.

13. The UV-curable composition of claim 1, wherein the photopolymerization initiator is an iodonium salt or a sulfonium salt.

14. The UV-curable composition of claim 1, wherein a content of the photopolymerization initiator is 1 to 15 wt % with respect to the total weight of the UV-curable ink composition.

15. The UV-curable composition of claim 1, wherein a content of the colorant is 1 to 15 wt % with respect to the total weight of the UV-curable ink composition.

16. The UV-curable composition of claim 2, wherein a content of the colorant is 0 to 30 wt % with respect to the total weight of the UV-curable ink composition.

17. The UV-curable composition of claim 2, wherein the photosensitizer is comprised in an amount of 1 to 200 parts by weight with respect to 100 parts by weight of the photopolymerization initiator.

18. The UV-curable composition of claim 1, wherein the adhesion promoter is comprised in an amount of 0.1 to 15 wt % with respect to the total weight of the UV-curable ink composition.

19. The UV-curable composition of claim 1, wherein a dose for curing the UV-curable ink composition is 1 to 10,000 mJ/cm.sup.2.

20. The UV-curable composition of claim 1, wherein the UV-curable ink composition has a viscosity of 1 cp to 50 cp at 25 C.

21. The UV-curable composition of claim 1, wherein the UV-curable ink composition has a taper angle of 0 to 30 after being cured.

22. The UV-curable composition of claim 1, wherein the UV-curable ink composition is for forming a bezel pattern.

23. A method for producing a bezel pattern for a display substrate, comprising: a) forming a bezel pattern on a substrate by using the UV-curable ink composition of claim 1; and b) curing the bezel pattern.

24. The method of claim 23, wherein the method of forming the bezel pattern on the substrate in Step a) is a method selected from an inkjet printing, a gravure coating, and a reverse offset coating.

25. A bezel pattern for a display substrate, which is formed on a substrate by curing the UV-curable ink composition of claim 1.

Description

EXAMPLES

(1) The compositions for forming a bezel pattern in Examples 1 to 4 and Comparative Examples 1 to 2 were prepared by mixing the compositions as in the following Table 1 and stirring the compositions for 3 hours.

(2) TABLE-US-00001 TABLE 1 Polymer- ization Adhesion Colorant Epoxy Oxetane initiator Surfactant promoter A B C D E F Example 1 A1: 3 B1: 15 C1: 77 D1: 3 E1: 1 F1: 1 2 A1: 3 B1: 15 C1: 77.5 D1: 3 E2: 0.5 F1: 1 3 A1: 5 B1: 25 C1: 64.5 D1: 3 E3: 1.5 F2: 1 4 A1: 3 B1: 15 C1: 77 D1: 3 E4: 1 F3: 1 Compar- ative Example 1 A1: 3 B1: 15 C1: 78 D1: 3 F3: 1 2 A1: 3 B1: 15 C1: 73 D1: 3 E5: 5 F3: 1 A1: Carbon black B1: Celloxide 2021P (Daicel Corp.) C1: ARON OXETANE 221 (Toagosei Co., Ltd.) D1: SP-150 (Asahi Denka) E1: RS-75 (DIC) E2: BYK-388 (BYK Chemie) E3: F-484 (DIC) E4: BYK-3441 (BYK Chemie) E5: BYK-330 (BYK Chemie) F1: 2-(3,4-epoxycyclohexyl)ethyltrimethoxy silane F2: 3-methacryloxypropyl triethoxysilane F3: 3-methacryloxyoctyl trimethoxysilane

Manufacture of Bezel Pattern

(3) The compositions prepared in Examples 1 to 4 and Comparative Examples 1 and 2 were cured on a cleaned LCD glass base material, and then were coated by the inkjet coating method so as to have a thickness of 2 m after the compositions were cured. Bezel patterns were formed by irradiating ultraviolet rays on the coating layer under the following conditions within 1 minute after the coating in order to prevent foreign substances from being attached and curing the compositions. As a UV ray irradiation device, a high-pressure mercury lamp having a wide ultraviolet ray emission wavelength region, or the like was used. After a UV ray of 1,000 mJ/cm.sup.2 was irradiated, latex gloves were worn in order to determine whether the bezel pattern was cured, and then the indentation and tack sense were observed by pressing the bezel pattern.

Manufacture of Display Device Using Bezel Pattern

(4) A bezel pattern was formed on the upper surface of the display panel (hereinafter, referred to as the panel) by the method in Preparation Example 1, and as an upper base material, an NRT polarization film manufactured by LG Chem., which used an acrylic adhesive layer, was attached thereto. After the attachment, the surroundings thereof were capped by a sealant in order to prevent moisture and foreign substance from being incorporated into the gap between the polarization film and the pattern.

: Viscosity

(5) For the compositions prepared in Examples 1 to 4 and Comparative Examples 1 and 2, viscosities were measured. As a viscosity measurement apparatus, DV-III+ manufactured by Brookfield Industries, Inc. was used.

: Measurement of Curing Sensitivity

(6) In order to measure the curing sensitivity of the bezel pattern manufactured according to Preparation Example 1, latex gloves were worn at the time point when 5 minutes elapsed after the irradiation of UV rays, and then the state of the surface was confirmed by pressing the bezel pattern.

(7) : The bezel pattern was not sticky, and completely cured

(8) : The bezel pattern was cured, but was sticky

(9) x: The bezel pattern was insufficiently cured, and as result, unreacted residues were spotted

: Evaluation of Spreadability

(10) The compositions prepared in Examples 1 to 4 and Comparative Examples 1 and 2 were applied on a cleaned LCD glass base material, and then the contact angles were measured.

: Evaluation of Attaching Force Between Film/Bezel Pattern

(11) A polarization film having a width of 25 mm and a length of 50 to 100 mm in size, on which an adhesive layer was applied, was attached to a bezel pattern at normal temperature by using a roll laminator. A 180 peel test was carried out and the results of measuring a peel strength when the film was peeled off from the bezel are shown in the following Table 2.

: Cross-Hatch Adhesion Force

(12) According to the ASTM D3359 standard which is a cross-cut test standard of the bezel pattern manufactured in Preparation Example 1, a cross-cut test was performed. Before the cross-cut test was performed, a heat treatment may be performed at a temperature of 60 C. for 1 minute in order to facilitate the reaction of the adhesion promoter according to the samples. Specifically, on a test sample, 11 lines were each scratched at an interval of 1 mm in the cross and machine directions to form 100 square lattices having a length and breadth of 1 mm each. And then, a CT-24 adhesive tap manufactured by Nichiban Co., Ltd. was attached to the cut surface, and then at the time of detaching the tape, the state of the surface which was falling apart together was measured to evaluate the state according to the following standard.

Evaluation Standard of Cross-Hatch Adhesive Force

(13) 5B: Case where no surface fell apart

(14) 4B: Case where the area of the fallen surface was within 5% compared to the total surface

(15) 3B: Case where the area of the fallen surface was 5 to 15% compared to the total surface

(16) 2B: Case where the area of the fallen surface was 15 to 35% compared to the total surface

(17) 1B: Case where the area of the fallen surface was 35 to 65% compared to the total surface

(18) 0B: Case where almost all the surface was fallen apart

(19) TABLE-US-00002 TABLE 2 Whether cured or not Spread- Upper 5 minutes ability portion Adhesion after UV Contact attaching force irradiation, angle force (at 5 O: tack-free O: <10 peel test minutes) Example Viscosity : Tack sense : 10 to 30 (Nichiban Cross Conditions (cP) X: Unreacted X: >30 tape) cut test 1 16 O O 500~1500 4B 2 16 O O 1500~2500 4B 3 24 O O 500~1000 4B 4 16 O O 1000~1500 4B Compar- ative Example 1 16 O X 10~200 4B 2 15 O O 10~50 4B

(20) As a result of the experiments, the ink compositions in Examples 1 to 4 in which a surfactant comprising a polar functional group was used exhibited low contact angles and high upper portion attaching forces, whereas there are problems in that the ink compositions in Comparative Examples 1 and 2, in which a surfactant comprising no polar functional group was used, exhibited high contact angle and had low upper portion attaching force, respectively.