OPTICAL LAMINATE AND FLEXIBLE DISPLAY DEVICE INCLUDING THE SAME

Abstract

This invention relates to an optical laminate comprising: a hard coating layer comprising polysiloxane; a primer layer; and an anti-finger print layer comprising a fluorine-containing compound, and having specific change in water contact angle and specific change in coefficient of friction, before and after conducting friction test on the anti-finger print layer; and a flexible display device including the same.

Claims

1. An optical laminate comprising: a hard coating layer comprising polysiloxane; a primer layer; and an anti-finger print layer comprising a fluorine-containing compound, wherein a water contact angle on a surface of the anti-finger print layer is 100° or more, before and after 1000 times reciprocating abrasion of steel wool under load of 500 g on the surface of the anti-finger print layer, a change in the water contact angle of the surface of the anti-finger print layer is 10° or less, and before and after 1000 times reciprocating abrasion of steel wool under load of 500 g on the surface of the anti-finger print layer, a change in a coefficient of friction of the surface of the anti-finger print layer is 0.2 or less.

2. The optical laminate according to claim 1, wherein the polysiloxane comprises 70 mol % or more of a repeat unit comprising an epoxy group-containing functional group.

3. The optical laminate according to claim 2, wherein the epoxy group-containing functional group is at least one group selected from the group consisting of an alicyclic epoxy group and a functional group represented by Chemical Formula 1: ##STR00002## in the Chemical Formula 1, R.sub.a is a substituted or unsubstituted C1-6 alkylene group, a substituted or unsubstituted C2-20 alkenylene group, a substituted or unsubstituted C2-20 alkynylene group, —R.sub.b—CH═CH—COO-R.sub.c—, —R.sub.d—OCO—CH═CH—R.sub.e—, —R.sub.fOR.sub.g—, —R.sub.hCOOR.sub.i—, or —R.sub.jOCOR.sub.k—, and R.sub.b to R.sub.k are each independently, a single bond; or a substituted or unsubstituted C1-6 alkylene group.

4. The optical laminate according to claim 2, wherein the polysiloxane has an epoxy group-containing functional group equivalent of 3.0 to 6.3 mmol/g.

5. The optical laminate according to claim 1, wherein the polysiloxane has a weight average molecular weight of 1,000 to 50,000 g/mol, a number average molecular weight of 1,000 to 10,000 g/mol and a polydispersity index of 1.0 to 10.0.

6. The optical laminate according to claim 1, wherein the hard coating layer further comprises, based on 100 parts by weight of the polysiloxane, 20 to 80 parts by weight of an elastic polymer.

7. The optical laminate according to claim 6, wherein the elastic polymer comprises polycaprolactone polyol.

8. The optical laminate according to claim 1, wherein the primer layer comprises an organic silane compound having at least one organic functional group selected from the group consisting of an epoxy group, a (meth)acryloxy group, a mercapto group, an amino group, a vinyl group and a ureido group.

9. The optical laminate according to claim 8, wherein the organic silane compound comprises at least one silane compound selected from the group consisting of 2-(3,4-epoxycyclohexyl)-ethyltrimethoxysilane, 3-glycidoxypropyl trimethoxysilane, 3-glycidoxypropyl methyldiethoxysilane, 3-glycidoxypropyl triethoxysilane, glycidoxypropyl methyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyl methyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyl trimethoxysilane, N-2-(aminoethyl)-3-aminopropyl triethoxysilane, 3-aminopropyl trimethoxysilane, 3-aminopropyl triethoxysilane, 3-uriedo propyl trimethoxysilane, 3-uriedo propyl trialkoxysilane, vinyl trimethoxysilane, vinyl triethoxysilane, methacryloxy trimethoxysilane, methacryloxy triethoxysilane, N-phenyl-γ-aminopropyl trimethoxy silane, and mercaptopropyl trimethoxysilane.

10. The optical laminate according to claim 8, wherein the primer layer further comprises at least one organic silane compound selected from the group consisting of methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, propyltrimethoxysilane, propyltriethoxysilane, and methyltributoxysilane.

11. The optical laminate according to claim 1, wherein the fluorine-containing compound comprises at least one compound selected from the group consisting of a perfluoro polyether compound, an oxyperfluoroalkylene group-containing compound, a fluoro-modified silane compound, and a fluoroalkyl group-containing compound.

12. The optical laminate according to claim 1, wherein a thickness ratio of the primer layer and the anti-finger print layer is 1:0.01 to 10,000.

13. The optical laminate according to claim 1, wherein the hard coating layer, the primer layer and the anti-finger print layer are sequentially laminated, and the optical laminate further comprises a support base layer positioned on one side of the hard coating layer so as to be opposite to the primer layer.

14. The optical laminate according to claim 13, further comprising an adhesive layer positioned on one side of the support base layer so as to be opposite to the hard coating layer.

15. A flexible display device including the optical laminate according to claim 1.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0131] FIG. 1 schematically shows a method of evaluating dynamic bending property.

[0132] The invention will be explained in more detail in the following examples. However, these examples are presented only as the illustrations of the invention, and the scope of the invention is not limited thereby.

PREPARATION EXAMPLE

Preparation Example 1-1: Preparation of a Resin Composition for Forming an Anti-Finger print layer (AF-1)

[0133] 1 g of a perfluoro-modified silane compound (product name: KY-185, manufacturing company: Shinetsu, weight average molecular weight: 520), 0.01 g of water, and 100 g of a hydrofluoroether as a fluorine-based solvent (product name: HFE-7200, manufacturing company: Novec) were mixed to prepare a resin composition for forming an anti-finger print layer (AF-1).

Preparation Example 1-2: Preparation of a Resin Composition for Forming an Anti-Finger Print Layer (AF-2)

[0134] 0.1 g of perfluoropolyethylene urethane acrylate (product name: AD1700, manufacturing company: SOLVAY, weight average molecular weight: 3000) and 100 g of a hydrofluoroether as a fluorine-based solvent (product name: HFE-7200, manufacturing company: Novec) were mixed to prepare a resin composition for forming an anti-finger print layer (AF-2).

Preparation Example 1-3: Preparation of a Resin Composition for Forming an Anti-Finger Print Layer (AF-3)

[0135] 50 g of 3-methacryloxypropyl trimethoxysilane (product name KBM-503 manufacturing company: Shinetsu), 50 g of trimethoxyphenylsilane (product name: phenyltrimethoxysilane, manufacturing company: Aldrich, molecular weight: 198), 1 g of a photoinitiator (Irgacure 127), 400 g of a 2-butanone as an organic solvent and 2 g of perfluoropolyethylene polymethacrylate were mixed to prepare a resin composition for forming an anti-finger print layer (AF-3).

Preparation Example 1-4: Preparation of a Resin Composition for Forming an Anti-Finger Print Layer (AF-4)

[0136] 15 g of perfluoropolyethylene urethane acrylate (product name: AD1700, manufacturing company: SOLVAY), 0.7 g of N-2-(aminoethyl)-3-aminopropyl trimethoxysilane and 84.3 g of trifluorotoluene were mixed to prepare a resin composition for forming an anti-finger print layer (AF-4).

Preparation Example 2: Preparation of a Resin Composition for Forming a Primer Layer (P-1)

[0137] 1 g of N-2-(aminoethyl)-3-aminopropyl trimethoxysilane, 0.3 g of methyltrimethoxysilane, 100 g of ethanol and 20 g of t-amyl alcohol were mixed to prepare a resin composition for forming a primer layer (P-1).

Preparation Example 3-1: Preparation of a Resin Composition for Forming a Hard Coating Layer (H-1)

[0138] Into a 1000 mL 3-neck flask, 3-glycidoxypropyl trimethoxysilane (GPTMS, KBM-403™, Shinetsu) as a silane monomer, water and toluene were introduced, and stirred (ratio of GPTMS:watertoluene=4 mol:1 mol:3 mol). To the resulting mixed solution, a basic catalyst(TMAH) was added in the amount of 1 part by weight, based on 100 parts by weight of the silane monomers, and reacted at 100° C. for 2 hours to prepare polysiloxane comprising 100 mol % of glycidoxypropyl modified silicon(hereinafter, referred to as ‘GP’) (number average molecular weight: 2,000 g/mol, polydispersity index(PDI): 1.4, glycipropyl equivalent: 6.0 mmol/g).

[0139] 10 g of the polysiloxane, 3 g of bisphenol A diglycidylether (Merck), 4 g of polycaprolactone diol (Mn: 530, Merck) and 0.3 g of iodinium,(4-methylphenyl)[4-(2-methylpropyl)phenyl]-,hexafluorophosphate(1-), (IGM resins) as an initiator were mixed to prepare a resin composition for forming a hard coating layer (H-1).

Preparation Example 3-2: Preparation of a Resin Composition for Forming a Hard Coating Layer (H-2)

[0140] A resin composition for forming a hard coating layer (H-2) was prepared by the same method as Preparation Example 3-1, except that 8 g of polycaprolactone diol (Mn: 530, Merck) was used instead of 4 g of polycaprolactone diol (Mn: 530, Merck).

Preparation Example 3-3: Preparation of a Resin Composition for Forming a Hard Coating Layer (H-3)

[0141] A resin composition for forming a hard coating layer (H-3) was prepared by the same method as Preparation Example 3-1, except that 6 g of bisphenol A diglycidylether was used instead of 3 g of bisphenol A diglycidylether.

EXAMPLE

Example 1

[0142] As described in the following Table 1, the compositions respectively prepared in the Preparation Examples were sequentially coated and cured to prepare an optical laminate.

[0143] Specifically, on one side of a polyethyleneterephthalate(PET) substrate(support base layer) of 15 cm×20 cm, and thickness of 50 μm, the resin composition for forming a hard coating layer (H-1) prepared in Preparation Example 3 was coated, and then, irradiated by UV (irradiation amount: 400 mJ/cm.sup.2) using a UV lamp to photocure, thus forming the lower hard coating layer with a thickness of 80 μm, and on the opposite side of the PET substrate, the resin composition for forming a hard coating layer (H-1) prepared in Preparation Example 3 was coated, and irradiated by UV (irradiation amount: 400 mJ/cm.sup.2) using a UV lamp to photocure, thus forming the upper hard coating layer with a thickness of 80 μm.

[0144] And then, the upper hard coating layer was surface-treated with plasma, and then, the resin composition for forming a primer layer (P-1) prepared in Preparation Example 2 was coated, and then, photocured at 110° C. for 30 minutes to form a primer layer with a thickness of 30 nm. On the primer layer, the resin composition for forming an anti-finger print layer (AF-1) prepared in Preparation Example 1-1 was coated, and then, photocured at 110° C. for 30 minutes to form an anti-finger print layer with a thickness of 10 nm, thereby preparing an optical laminate.

Example 2

[0145] An optical laminate was prepared by the same method as Example 1, except that the resin composition for forming an anti-finger print layer (AF-2) prepared in Preparation Example 1-2 was used instead of the resin composition for forming an anti-finger print layer (AF-1) prepared in Preparation Example 1-1, and that the lower hard coating layer was not formed.

Example 3

[0146] An optical laminate was prepared by the same method as Example 1, except that the resin composition for forming an anti-finger print layer (AF-2) prepared in Preparation Example 1-2 was used instead of the resin composition for forming an anti-finger print layer (AF-1) prepared in Preparation Example 1-1.

Comparative Example 1

[0147] An optical laminate was prepared by the same method as Example 1, except that the resin composition for forming an anti-finger print layer (AF-2) prepared in Preparation Example 1-2 was used instead of the resin composition for forming an anti-finger print layer (AF-1) prepared in Preparation Example 1-1, and that the primer layer was not formed.

Comparative Example 2

[0148] On one side of a polyethyleneterephthalate(PET) substrate(support base layer) of 15 cm×20 cm, and thickness of 50 μm, the resin composition for forming a hard coating layer (H-1) prepared in Preparation Example 3 was coated, and then, irradiated by UV (irradiation amount: 400 mJ/cm.sup.2) using a UV lamp to photocure, thus forming the lower hard coating layer with a thickness of 80 μm, and on the opposite side of the PET substrate, the resin composition for forming an anti-finger print layer (AF-3) prepared in Preparation Example 1-3 was coated, and irradiated by UV (irradiation amount: 400 mJ/cm.sup.2) using a UV lamp to photocure, thus forming an anti-finger print layer with a thickness of 10 nm, thereby preparing an optical laminate.

Comparative Example 3

[0149] An optical laminate was prepared by the same method as Example 1, except that the resin composition for forming an anti-finger print layer (AF-4) prepared in Preparation Example 1-4 was used instead of the resin composition for forming an anti-finger print layer (AF-1) prepared in Preparation Example 1-1, and that the primer layer was not formed.

Comparative Example 4

[0150] An optical laminate was prepared by the same method as Example 1, except that the resin composition for forming a hard coating layer (H-2) prepared in Preparation Example 3-2 was used instead of the resin composition for forming a hard coating layer (H-1) prepared in Preparation Example 3-1.

Comparative Example 5

[0151] An optical laminate was prepared by the same method as Example 1, except that the resin composition for forming a hard coating layer (H-3) prepared in Preparation Example 3-3 was used instead of the resin composition for forming a hard coating layer (H-1) prepared in Preparation Example 3-1.

TABLE-US-00001 TABLE 1 Example Example Example Comparative Comparative Comparative Comparative Comparative 1 2 3 Example 1 Example 2 Example 3 Example 4 Example 5 Anti-finger Preparation Preparation Preparation Preparation — Preparation Preparation Preparation print layer Example 1-1 Example 1-2 Example 1-2 Example 1-2 Example 1-4 Example 1-1 Example 1-1 (AF-1) (AF-2) (AF-2) (AF-2) (AF-4) (AF-1) (AF-1) Primer layer Preparation Preparation Preparation — — — Preparation Preparation Example 2 Example 2 Example 2 Example 2 Example 2 (P-1) (P-1) (P-1) (P-1) (P-1) Upper hard Preparation Preparation Preparation Preparation Preparation Preparation Preparation Preparation coating layer Example 3-1 Example 3-1 Example 3-1 Example 3-1 Example 1-3 Example 3-1 Example 3-2 Example 3-3 (H-1) (H-1) (H-1) (H-1) (AF-3) (H-1) (H-2) (H-3) Support base PET PET PET PET PET PET PET PET layer Lower hard Preparation — Preparation Preparation Preparation Preparation Preparation Preparation coating layer Example 3-1 Example 3-1 Example 3-1 Example 3-1 Example 3-1 Example 3-2 Example 3-3 (H-1) (H-1) (H-1) (H-1) (H-1) (H-2) (H-3)

Experimental Example

[0152] For the optical laminates prepared in Examples and Comparative Examples, the properties were measured as follows, and the results were shown in the following Table 2.

1. Measurement of Water Contact Angle before and after Steel Wool Test

[0153] For each anti-finger print layer of Examples and Comparative Examples (in the case of Comparative Example 2, the upper hard coating layer), a water contact angle was measured using a contact angle analyzer (CAX-150). When measuring a contact angle, the size of one water drop was 3 , and in order to confirm the uniformity of coating, contact angles of 5 points were measured per one coated sample and then averaged, and the result was described in water contact angle before steel wool test in the following Table 2.

[0154] And then, after 1000 times reciprocating abrasion of steel wool(#0000) under load of 500 g on the surface of the anti-finger print layer, a water contact angle was measured for the surface of the anti-finger print layer by the same method as explained above, and the result was described in water contact angle after steel wool test in the following Table 2.

2. Measurement of Coefficient of Friction before and after Steel Wool Test

[0155] For each anti-finger print layer of Examples and Comparative Examples (in the case of Comparative Example 2, the upper hard coating layer), coefficient of static friction was measured according to ASTM D1894 using a friction tester (Toyoseiki, Model TR type), and the result was described in coefficient of friction before steel wool test in the following Table 2.

[0156] And then, after 1000 times reciprocating abrasion of steel wool (#0000) under load of 500 g on the surface of the anti-finger print layer, coefficient of static friction was measured according to ASTM D1894 for the surface of the anti-finger print layer, and the result was described in coefficient of friction after steel wool test in the following Table 2.

3. Evaluation of Scratch Resistance

[0157] After 1000 times reciprocating abrasion with steel wool(#0000) under load of 500 g on the surface of each anti-finger print layer of Examples and Comparative Examples (in the case of Comparative Example 2, the upper hard coating layer), it was confirmed with the naked eye whether or not scratch was generated, and it was judged as “O.K.” when scratch of 3 mm or less was generated, and as “N.G.” when scratch greater than 3 mm was generated.

4. Evaluation of Eraser Abrasion

[0158] After 1500 times reciprocating abrasion of Minoan eraser under load of 500 g on the surface of each anti-finger print layer of Examples and Comparative Examples (in the case of Comparative Example 2, the upper hard coating layer), it was confirmed with the naked eye whether or not the coating film was abraded (scratch, Haze), and it was judged as “O.K.” when there was no deformation, and as “N.G.” when abrasion deformation was generated.

5. Evaluation of Dynamic Bending Property

[0159] FIG. 1 schematically shows a method of evaluating dynamic bending property for the optical laminate according to one example of the invention.

[0160] The optical laminate was laser cut to a size of 80×140 mm so as to minimize fine cracks at the edge. On a measuring device, the laser cut film was put, and with the lower hard coating layer(in the case of Example 2, support base layer) being inside, and with a distance between folded parts (inner diameter of curvature) being 3 mm, continuous movement of folding both sides of the film at 90 degree to the bottom surface and unfolding was repeated 200,000 times at room temperature (film folding speed: one time per 1.5 seconds), and dynamic bending property was evaluated according to the following standard.

[0161] O.K.: No crack generated

[0162] N.G.: Crack generated

TABLE-US-00002 TABLE 2 Comparative Comparative Comparative Comparative Comparative Example 1 Example 2 Example 3 Example 1 Example 2 Example 3 Example 4 Example 5 Water contact Before steel 115° 115° 110° 110° 80° 112° 111° 111° angle wool evaluation After steel 107° 110° 103°  75° 65°  75° 103°  75° wool evaluation Coefficient Before steel   0.09   0.09   0.05   0.10   0.40   0.09   0.09   0.08 of friction wool evaluation After steel   0.24   0.22   0.18   0.41   0.70   0.45   0.25   0.40 wool evaluation Scratch resistance O.K. O.K. O.K. N.G. N.G. N.G. N.G. N.G. Eraser abrasion degree O.K. O.K. O.K. N.G. N.G. N.G. N.G. N.G. Dynamic bending property O.K. O.K. O.K. O.K. O.K. O.K. O.K. O.K.

[0163] According to Table 2, it was confirmed that since each optical laminate of Examples 1 to 3 sequentially comprise a hard coating layer, a primer layer and an anti-finger print layer, and before and after a steel wool test, has a change in a water contact angle of 10° or less, and a change in a coefficient of friction of 0.2 or less, it exhibits excellent scratch resistance and eraser abrasion, and exhibits dynamic bending property to such a degree that cracks are not generated even if continuous movement of folding and unfolding was repeated 200,000 times.

[0164] Meanwhile, it was confirmed that in the case of the optical laminates of Comparative Examples, since a primer layer is not included, or a hard coating layer having a composition different from the invention is used, adhesion between the upper hard coating layer and anti-finger print layer is weak, and thus, scratch resistance and abrasion resistance are inferior, and change in water contact angle and change in coefficient of friction before and after steel wool test are large.