Glass Substrate Multilayer Structure, a Method for Manufacturing the Same, and a Display Panel Including the Same

Abstract

Provided are a glass substrate multilayer structure including a glass substrate; a polyimide-based shatter-proof layer formed on one surface of the glass substrate; and a hard coating layer formed on the polyimide-based shatter-proof layer. The polyimide-based shatter-proof layer has a thickness of 5 to 50 μm, the hard coating layer has a thickness of 5 to 20 μm, and the glass substrate multilayer structure has a retardation in a thickness direction (R.sub.th) of 200 nm or less. A method for manufacturing the glass substrate multilayer structure, and a display panel including the glass substrate multilayer structure are also provided.

Claims

1. A glass substrate multilayer structure comprising: a glass substrate; a polyimide-based shatter-proof layer formed on one surface of the glass substrate; and a hard coating layer formed on the polyimide-based shatter-proof layer, wherein the polyimide-based shatter-proof layer has a thickness of 5 to 50 μm, the hard coating layer has a thickness of 5 to 20 μm, and the glass substrate multilayer structure has a retardation in a thickness direction (R.sub.th) of 200 nm or less.

2. The glass substrate multilayer structure of claim 1, wherein the polyimide-based shatter-proof layer comprises a polyimide polymer comprising a unit derived from an aromatic diamine and an aromatic dianhydride.

3. The glass substrate multilayer structure of claim 1, wherein the polyimide-based shatter-proof layer further comprises a polyfunctional (meth)acrylic crosslinked polymer.

4. The glass substrate multilayer structure of claim 1, wherein the hard coating layer comprises a unit derived from a condensate of alkoxysilane having an epoxy group.

5. The glass substrate multilayer structure of claim 4, wherein the condensate of alkoxysilane having an epoxy group is a silsesquioxane resin having an epoxy group.

6. The glass substrate multilayer structure of claim 4, wherein the hard coating layer further comprises a unit derived from a crosslinking agent having a polyfunctional epoxy group.

7. The glass substrate multilayer structure of claim 1, wherein the glass substrate has a thickness of 100 to 1000 μm.

8. The glass substrate multilayer structure of claim 1, wherein the glass substrate multilayer structure has a flame retardant grade of V-0 as evaluated in accordance with a UL-94 VB flame retardant specification.

9. The glass substrate multilayer structure of claim 1, wherein a surface of the hard coating layer of the glass substrate multilayer structure has a surface hardness in accordance with ASTM D3363 of 4 H or more.

10. A method for manufacturing a glass substrate multilayer structure, the method comprising the steps of: applying a shatter-proof layer forming composition on one surface of a glass substrate and curing the composition to form a polyimide-based shatter-proof layer; and applying a hard coating layer forming composition on the polyimide-based shatter-proof layer and curing the composition to form a hard coating layer, wherein the polyimide-based shatter-proof layer has a thickness of 5 to 50 μm, the hard coating layer has a thickness of 5 to 20 μm, and the glass substrate multilayer structure has a retardation in a thickness direction (R.sub.th) of 200 nm or less thereof.

11. The method for manufacturing a glass substrate multilayer structure of claim 10, wherein the shatter-proof layer forming composition comprises a polyimide polymer comprising a unit derived from an aromatic diamine and an aromatic dianhydride.

12. The method for manufacturing a glass substrate multilayer structure of claim 10, wherein the shatter-proof layer forming composition further comprises a compound having a polyfunctional (meth)acryl group.

13. The method for manufacturing a glass substrate multilayer structure of claim 10, wherein the hard coating layer forming composition comprises a condensate of alkoxysilane having an epoxy group.

14. The method for manufacturing a glass substrate multilayer structure of claim 13, wherein the condensate of alkoxysilane having an epoxy group is a silsesquioxane resin having an epoxy group.

15. The method for manufacturing a glass substrate multilayer structure of claim 13, wherein the hard coating layer forming composition further comprises a crosslinking agent having a polyfunctional epoxy group.

16. The method for manufacturing a glass substrate multilayer structure of claim 10, wherein the glass substrate multilayer structure has a flame retardant grade of V-0 as evaluated in accordance with a UL-94 VB flame retardant specification.

17. The method for manufacturing a glass substrate multilayer structure of claim 10, wherein a surface of the hard coating layer of the glass substrate multilayer structure has a surface hardness in accordance with ASTM D3363 of 4 H or more.

18. A display panel comprising the glass substrate multilayer structure according to claim 1.

Description

PREPARATION EXAMPLE 1

(Preparation of Shatter-Proof Layer Forming Composition)

[0173] An agitator in which a nitrogen stream flowed was filled with 267 g of N,N-dimethylpropionamide (DMPA), and 39 g of 2,2′-Bis(trifluoromethyl)benzidine (TFMB) was dissolved therein while the temperature of the reactor was maintained at 25° C. 50 g of ethylene glycol bis-anhydro trimellitate (TMEG100) was added to the TFMB solution at the same temperature, and polymerization was performed while stirring was performed for 48 hours. Finally, dimethylpropaneamide (DMPA) was added so that the solid content concentration was 20 wt %, thereby preparing a polyamic acid solution which was a precursor of the shatter-proof layer forming composition.

[0174] To the polyimide-based resin solution, an organic additive (dipentaerythritol hexaacrylate (DPHA), 50%) was added so that it was 15 wt % with respect to the solid content to prepare the shatter-proof layer forming composition.

COMPARATIVE PREPARATION EXAMPLE 1

(Preparation of Shatter-Proof Layer Forming Composition)

[0175] 61.9 mg of a Grubbs catalyst and 10 ml of methylene chloride (MC) were added to a reactor under a nitrogen atmosphere, stirring was performed for 12 hours, 0.8 g of dicyclopentadiene dissolved in 10 ml of methylene chloride (MC) was added to the reactor, and the reaction was performed at room temperature for 2 hours.

[0176] After the reaction was finished, the reaction solution was transferred to a high-pressure reactor, 100 ml of MC, 0.014 ml of triethylamine, and 0.01 ml of MeOH were added to the reaction solution, hydrogen gas (H.sub.2 (g)) at a pressure of 100 psi was added, the temperature was raised up to 60° C., and stirring was performed for 12 hours, thereby preparing a shatter-proof layer forming composition.

PREPARATION EXAMPLE 2

Preparation of Hard Coating Layer Forming Composition)

[0177] 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane (ECTMS, TCI) and water were mixed at a ratio of 24.64 g: 2.70 g (0.1 mol: 0.15 mol) to prepare a reaction solution and the reaction solution was added to a 250 mL 2-neck flask. 0.1 mL of a tetramethylammonium hydroxide catalyst (Aldrich) and 100 mL of tetrahydrofuran (Aldrich) were added to the mixture and stirring was performed at 25° C. for 36 hours.

[0178] Thereafter, layer separation was performed and a product layer was extracted with methylene chloride (Aldrich), moisture was removed from the extract with magnesium sulfate (Aldrich), and the solvent was dried under vacuum to obtain an epoxy siloxane-based resin.

[0179] 30 g of the epoxy siloxane-based resin as prepared above, g of (3′,4′-epoxycyclohexyl)methyl 3,4-epoxycyclohexanecarboxylate and 5 g of bis[(3,4-epoxycyclohexyl)methyl] adipate as a crosslinking agent, 0.5 g of (4-methylphenyl)[4-(2-methylpropyl)phenyl]iodoniumhexafluorophosphate as a photoinitiator, and 54.5 g of methyl ethyl ketone were mixed, thereby preparing a hard coating layer forming composition.

<Manufacture of Glass Substrate Multilayer Structure>

EXAMPLE 1

[0180] On one surface of a glass substrate having a thickness of 700 μm, the shatter-proof layer forming composition prepared in Preparation Example 1 was applied using a doctor blade, and the composition was dried at 80° C. for 10 minutes and at 230° C. for 10 minutes under a nitrogen atmosphere, thereby forming a shatter-proof layer having a thickness of 5 μm. Then, on the shatter-proof layer, the hard coating layer forming composition prepared in Preparation Example 2 was applied using a #10 Mayer bar, and dried at 60° C. for 3 minutes. Thereafter, UV rays were irradiated at 1 J/cm.sup.2 using a high pressure metal lamp, and curing was performed at 150° C. for 10 minutes, thereby manufacturing a glass substrate multilayer structure having a hard coating layer having a thickness of 10 μm formed thereon. The results are listed in Table 1.

EXAMPLE 2

[0181] A glass substrate multilayer structure was manufactured in the same manner as in Example 1, except that the thickness of the shatter-proof layer was 11 μm. The results are listed in Table 1.

EXAMPLE 3

[0182] A glass substrate multilayer structure was manufactured in the same manner as in Example 1, except that the thickness of the shatter-proof layer was 20 μm. The results are listed in Table 1.

EXAMPLE 4

[0183] A glass substrate multilayer structure was manufactured in the same manner as in Example 1, except that the thickness of the shatter-proof layer was 50 μm. The results are listed in Table 1.

COMPARATIVE EXAMPLE 1

[0184] A glass substrate multilayer structure was manufactured in the same manner as in Example 2, except that the shatter-proof layer was formed using the shatter-proof layer forming composition prepared in Comparative Preparation Example 1, instead of using the shatter-proof layer forming composition prepared in Preparation Example 1. The results are listed in Table 1.

COMPARATIVE EXAMPLE 2

[0185] A glass substrate multilayer structure was manufactured in the same manner as in Example 1, except that the thickness of the shatter-proof layer was 4 μm. The results are listed in Table 1.

COMPARATIVE EXAMPLE 3

[0186] A glass substrate multilayer structure was manufactured in the same manner as in Example 1, except that the thickness of the shatter-proof layer was 60 μm. The results are listed in Table 1.

COMPARATIVE EXAMPLE 4

[0187] A glass substrate multilayer structure was manufactured in the same manner as in Example 1, except that the thickness of the hard coating layer was 100 μm and the thickness of the shatter-proof layer was 11 μm. The results are listed in Table 1.

COMPARATIVE EXAMPLE 5

[0188] A glass substrate multilayer structure was manufactured in the same manner as in Example 1, except that the thickness of the shatter-proof layer was 11 μm and the thickness of the hard coating layer was 1 μm. The results are listed in Table 1.

TABLE-US-00001 TABLE 2 Thickness of Thickness of Flame Light Yellow shatter-proof hard coating Ren Rainbow retardant Surface Shattering transmittance index layer (μm) layer (μm) (nm) phenomenon grade hardness resistance (%) (YI) Example 1 5 10 10 OK V-0 6H OK 90.8 1.1 Example 2 11 10 20 OK V-0 5H OK 90.6 1.4 Example 3 20 10 36 OK V-0 5H OK 90.9 1.6 Example 4 50 10 79 OK V-0 4H OK 90.9 2.0 Comparative 11 10 10 OK V-3 3H OK 89.8 1.5 Example 1 Comparative 4 10 39 OK V-0 3H NG 91.0 1.3 Example 2 Comparative 60 10 90 NG V-0 4B OK 89.6 2.3 Example 3 Comparative 11 100 201 NG V-0 5H NG 90.5 1.5 Example 4 Comparative 11 1 109 OK V-0 6B OK 90.8 1.9 Example 5

[0189] Referring to Table 1 above, it was confirmed that the glass substrate multilayer structures of Examples 1 to 4 had excellent photoisotropy, had no rainbow phenomenon to be observed so that visibility was very good, and had a flame retardant grade of V-0 as evaluated in accordance with the UL-94 VB flame retardant specification so that flammability resistance was very good.

[0190] In addition, it was confirmed that the glass substrate multilayer structures of Examples 1 to 4 had no breakage even when a steel ball (weight: 500 g) was dropped from a height of 300 m, so that it had very good shattering resistance, and had a very good surface hardness of 4 H or more, and also had excellent optical properties such as light transmittance and yellow index (YI).

[0191] However, in Comparative Examples 1 to 5, the scope of thickness and the retardation values were out of the range described above, and thus, the physical properties satisfying no rainbow phenomenon occurrence and excellent visibility were not shown. In addition, it was confirmed that the glass substrate multilayer structure of Comparative Example 1 to which a COP film was applied as a shatter-proof layer had a flame retardant grade of V-3 as evaluated in accordance with the UL-94 VB flame retardant specification, so that flammability resistance was significantly lowered, and its surface hardness was deteriorated.

[0192] Accordingly, the glass substrate multilayer structures of Examples 1 to 4 included a polyimide-based shatter-proof layer having a thickness of 5 to 50 μm formed on one surface of a glass substrate and a hard coating layer having a thickness of 5 to 20 μm formed on the polyimide-based shatter-proof layer, and had a retardation in the thickness direction (R.sub.th) of 200 nm or less, thereby improving a shattering phenomenon when the glass substrate is broken, securing users' safety since it is not easily burned by fire, significantly improving visibility with excellent photoisotropy, and having excellent surface properties and optical properties.

[0193] A glass substrate multilayer structure, which may secure excellent surface hardness, shattering resistance to external impact, and flammability resistance, does not cause a rainbow phenomenon, and has optical properties such as visibility, transparency, light transmittance, and yellow index, even with a thin shatter-proof layer provided, may be provided.

[0194] In addition, a method for manufacturing a glass substrate multilayer structure having the physical properties described above may be provided.

[0195] Hereinabove, although the present disclosure has been described by specified matters and specific exemplary embodiments, they have been provided only for assisting in the entire understanding of the present disclosure. Therefore, the present disclosure is not by the specific matters limited to the exemplary embodiments. Various modifications and changes may be made by those skilled in the art to which the present disclosure pertains from this description.

[0196] Therefore, the spirit of the present disclosure should not be limited to the above-described exemplary embodiments, and the following claims as well as all modified equally or equivalently to the claims are intended to fall within the scope and spirit of the invention.