COATING RESIN COMPOSITION AND COATING FILM COMPRISING CURED ARTICLE THEREOF AS COATING LAYER

Abstract

The present invention relates to a coating resin composition comprising a siloxane resin chemically bonded by compounds including an alkoxy silane containing epoxy or acrylic in the chemical structure; a dialkoxysilane of a silane D structure; or a trialkoxy silane of a silane T structure, and to a coating film comprising a cured article of the resin composition as a coating layer.

Claims

1. A resin composition for coating comprising a siloxane resin obtained through a chemical bond of compounds comprising: an alkoxysilane represented by the following Formula 1; an alkoxysilane represented by the following Formula 2, and a diol represented by the following Formula 4,
R.sup.1.sub.nSi(OR.sup.2).sub.4-n   <Formula 1> wherein R.sup.1 is a glycidoxypropylene group, R.sup.2 is a methyl group, and n is 1,
R.sup.3Si (OR.sup.4).sub.3   <Formula 2> wherein R.sup.3 and R.sup.4 each independently represent a C1 to C4 linear or branched alkyl group,
HO(CH.sub.2).sub.nOH   <Formula 4> wherein n is an integer of 1 to 10, and wherein the alkoxysilane represented by Formula 2 is present in a molar ratio (%) of 10 to 100 moles with respect to a total of 100 moles of the alkoxysilane represented by Formula 1, and the diol represented by the Formula 4 is incorporated in a polymerization of the siloxane resin, and a linear structure of the diol is introduced into polymer chains of the siloxane resin.

2. The resin composition for coating according to claim 1, wherein the diol is present in a molar ratio (%) of 10 to 150 moles with respect to a total of 100 moles of the alkoxysilane represented by Formula 1.

3. The resin composition for coating according to claim 1, wherein the alkoxysilane represented by Formula 1 comprises at least one selected from 3-glycidoxypropyl trimethoxysilane, 3-glycidoxypropyl triethoxysilane, 3-glycidoxypropyl tripropoxysilane, 3-methacryloxypropyl trimethoxysilane, 3-methacryloxypropyl triethoxysilane, 3-acryloxypropyl trimethoxysilane, 3-acryloxypropyl triethoxysilane, 3-acryloxypropyl tripropoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane and 2-(3,4-epoxycyclohexyl)ethyltripropoxysilane.

4. The resin composition for coating according to claim 1, wherein the siloxane resin has a weight average molecular weight of 1,000 to 10,000 and a molecular weight distribution of 1.2 to 2.7.

5. The resin composition for coating according to claim 1, further comprising least one additive selected from the group consisting of an organic solvent, a photoinitiator, a thermal initiator, an antioxidant, a leveling agent and a coating aid.

6. A coating film comprising: a base film; and a coating layer laminated on at least one surface of the base film and comprising a cured product of the resin composition for coating according to claim 1.

7. The coating film according to claim 6, wherein the coating film has a surface hardness in a direction in which the coating layer is formed, measured in accordance with ASTM D3363, of 5H or more.

8. The resin composition for coating according to claim 1, wherein the siloxane resin is obtained through a chemical bond of compounds further comprising an alkoxysilane represented by Formula 3:
R.sup.5.sub.2Si (OR.sup.6).sub.2   <Formula 3> wherein R.sup.5 and R.sup.6 each independently represent a C1 to C4 linear or branched alkyl group.

9. The resin composition for coating according to claim 1, wherein the alkoxysilanes represented by Formula 2 and Formula 3 are present in a molar ratio (%) of 10 to 100 moles with respect to a total of 100 moles of the alkoxysilane represented by Formula 1.

10. The resin composition for coating according to claim 2, wherein the molar ratio of the alkoxysilane represented by Formula 2 and the alkoxysilane represented by Formula 3 is 1:0.1 to 1:10.

Description

EXAMPLE 1

[0050] KBM-403 (Shin-Etsu Chemical Co., Ltd.), TEMS (Sigma-Aldrich Corporation) and distilled water were mixed at a ratio of 414 g:134 g:67 g (1.75 mol:0.75 mol:3.75 mol), the resulting mixture was injected into a 1,000 mL double-jacket reactor, a sodium hydroxide solution (NaOH 0.1 g in H.sub.2O 1g) was added as a catalyst, and the mixture was stirred at 200 RPM with a mechanical stirrer at 90° C. for 8 hours using a thermostat. Then, the resulting mixture was diluted with 2-butanone to realize a solid content of 50 wt %, and was then filtered through a 0.45 μm Teflon filter to obtain a siloxane resin. The molecular weight of the resin was measured using GPC, and the result showed that the resin had a number average molecular weight of 4,527, a weight average molecular weight of 6,280, and a polydispersity index (PDI, Mw/Mn) of 1.38.

[0051] Next, 3 parts by weight of IRGACURE 250 (BASF Corporation), which is a photoinitiator, with respect to 100 parts by weight of the siloxane resin, was added to the siloxane resin diluted in the solvent to finally obtain a resin composition for coating.

[0052] This composition was coated on the polyimide surface using a bar, dried at 80° C. for 20 minutes and then exposed to an ultraviolet lamp having a wavelength of 315 nm for 30 seconds to prepare a coating film with a thickness of 10 μm.

EXAMPLE 2

[0053] KBM-403 (Shin-Etsu Chemical Co., Ltd.), DMDMS (Sigma-Aldrich Corporation) and distilled water were mixed at a ratio of 414 g:90 g:60 g (1.75 mol:0.75 mol:3.375 mol), the resulting mixture was injected into a 1,000 mL double-jacket reactor, a sodium hydroxide solution (NaOH 0.1 g in H.sub.2O 1 g) was added as a catalyst, and the mixture was stirred at 200 RPM with a mechanical stirrer at 90° C. for 8 hours using a thermostat. Then, the resulting mixture was diluted with 2-butanone to realize a solid content of 50 wt %, and was then filtered through a 0.45 μm Teflon filter to obtain a siloxane resin. The molecular weight of the resin was measured using GPC, and the result showed that the resin had a number average molecular weight of 3,216, a weight average molecular weight of 5,323, and a polydispersity index (PDI, Mw/Mn) of 1.65. Next, a resin composition for coating was prepared in the same manner as in Example 1, and a polyimide film was coated therewith to prepare a coating film with a thickness of 10 μm.

EXAMPLE 3

[0054] KBM-403 (Shin-Etsu Chemical Co., Ltd.), TEMS (Sigma-Aldrich Corporation) and distilled water were mixed at a ratio of 537 g:41.4 g:67.5 g (2.27 mol:0.23 mol:3.75 mol), the resulting mixture was injected into a 1,000 mL double-jacket reactor, a sodium hydroxide solution (NaOH 0.1 g in H.sub.2O 1 g) was added as a catalyst, and the mixture was stirred at 200 RPM with a mechanical stirrer at 90° C. for 8 hours using a thermostat. Then, the resulting mixture was diluted with 2-butanone to realize a solid content of 50 wt %, and was then filtered through a 0.45 μm Teflon filter to obtain a siloxane resin. The molecular weight of the resin was measured using GPC, and the result showed that the resin had a number average molecular weight of 5,897, a weight average molecular weight of 8,721, and a polydispersity index (PDI, Mw/Mn) of 1.47. Next, a resin composition for coating was prepared in the same manner as in Example 1 and a polyimide film was coated therewith to prepare a coating film with a thickness of 10 μm.

EXAMPLE 4

[0055] KBM-503 (Shin-Etsu Chemical Co., Ltd.), TEMS (Sigma-Aldrich Corporation) and distilled water were mixed at a ratio of 435 g:134 g:67 g (1.75 mol:0.75 mol:3.75 mol), the resulting mixture was injected into a 1,000 mL double-jacket reactor, a sodium hydroxide solution (NaOH 0.1 g in H.sub.2O 1 g) was added as a catalyst, and the mixture was stirred at 200 RPM with a mechanical stirrer at 90° C. for 8 hours using a thermostat. Then, the resulting mixture was diluted with 2-butanone to realize a solid content of 50 wt %, and was then filtered through a 0.45 μm Teflon filter to obtain a siloxane resin. The molecular weight of the resin was measured using GPC, and the result showed that the resin had a number average molecular weight of 4,383, a weight average molecular weight of 6,671, and a polydispersity index (PDI, Mw/Mn) of 1.52. Next, a resin composition for coating was prepared in the same manner as in Example 1, and a polyimide film was coated therewith to prepare a coating film with a thickness of 10 μm.

EXAMPLE 5

[0056] KBM-503 (Shin-Etsu Chemical Co., Ltd.), DMDMS (Sigma-Aldrich Corporation) and distilled water were mixed at a ratio of 435 g:90 g:61 g (1.75 mol:0.75 mol:3.375 mol), the resulting mixture was injected into a 1,000 mL double-jacket reactor, and a sodium hydroxide solution (NaOH 0.1 g in H.sub.2O 1 g) was added as a catalyst, and the mixture was stirred at 200 RPM with a mechanical stirrer at 90° C. for 8 hours using a thermostat. Then, the resulting mixture was diluted with 2-butanone to realize a solid content of 50 wt %, and was then filtered through a 0.45 μm Teflon filter to obtain a siloxane resin. The molecular weight of the resin was measured using GPC, and the result showed that the resin had a number average molecular weight of 3,317, a weight average molecular weight of 5,681, and a polydispersity index (PDI, Mw/Mn) of 1.71. Next, a resin composition for coating was prepared in the same manner as in Example 1, and a polyimide film was coated therewith to prepare a coating film with a thickness of 10 μm.

EXAMPLE 6

[0057] KBM-403 (Shin-Etsu Chemical Co., Ltd.), TEMS (Sigma-Aldrich Corporation), ethylene glycol (Sigma-Aldrich Corporation) and distilled water were mixed at a ratio of 414 g:134 g:116 g:34 g (1.75 mol:0.75 mol:1.875 mol:1.875 mol), the resulting mixture was injected into a 1,000 mL double-jacket reactor, and a sodium hydroxide solution (NaOH 0.1 g in H.sub.2O 1 g) was added as a catalyst and the mixture was stirred at 200 RPM with a mechanical stirrer at 90° C. for 8 hours using a thermostat. Then, the resulting mixture was diluted with 2-butanone to realize a solid content of 50 wt %, and was then filtered through a 0.45 μm Teflon filter to obtain a siloxane resin. The molecular weight of the resin was measured using GPC, and the result showed that the resin had a number average molecular weight of 1,139, a weight average molecular weight of 2,131, and a polydispersity index (PDI, Mw/Mn) of 1.87. Next, a resin composition for coating was prepared in the same manner as in Example 1, and a polyimide film was coated therewith to prepare a coating film with a thickness of 10 μm.

EXAMPLE 7

[0058] KBM-403 (Shin-Etsu Chemical Co., Ltd.), DMDMS (Sigma-Aldrich Corporation), ethylene glycol (Sigma-Aldrich Corporation) and distilled water were mixed at a ratio of 414 g:90 g:104 g:30g (1.75 mol:0.75 mol:1.688 mol:1.688 mol), the resulting mixture was injected into a 1,000 mL double-jacket reactor, a sodium hydroxide solution (NaOH 0.1 g in H.sub.2O 1g) was added as a catalyst, and the mixture was stirred at 200 RPM with a mechanical stirrer at 90° C. for 8 hours using a thermostat. Then, the resulting mixture was diluted with 2-butanone to realize a solid content of 50 wt %, and was then filtered through a 0.45 μm Teflon filter to obtain a siloxane resin. The molecular weight of the resin was measured using GPC, and the result showed that the resin had a number average molecular weight of 1,039, a weight average molecular weight of 1, 721, and a polydispersity index (PDI, Mw/Mn) of 1.65. Next, a resin composition for coating was prepared in the same manner as in Example 1, and a polyimide film was coated therewith to prepare a coating film with a thickness of 10 μm.

EXAMPLE 8

[0059] KBM-503 (Shin-Etsu Chemical Co., Ltd.), TEMS (Sigma-Aldrich Corporation), ethylene glycol (Sigma-Aldrich Corporation) and distilled water were mixed at a ratio of 435 g:134 g:116 g:34 g (1.75 mol:0.75 mol:1.875 mol:1.875 mol), the resulting mixture was injected into a 1,000 mL double-jacket reactor, a sodium hydroxide solution (NaOH 0.1 g in H.sub.2O 1g) was added as a catalyst and the mixture was stirred at 200 RPM with a mechanical stirrer at 90° C. for 8 hours using a thermostat. Then, the resulting mixture was diluted with 2-butanone to realize a solid content of 50 wt %, and was then filtered through a 0.45 μm Teflon filter to obtain a siloxane resin. The molecular weight of the resin was measured using GPC, and the result showed that the resin had a number average molecular weight of 1,213, a weight average molecular weight of 2,407, and a polydispersity index (PDI, Mw/Mn) of 1.98. Next, a resin composition for coating was prepared in the same manner as in Example 1, and a polyimide film was coated therewith to prepare a coating film with a thickness of 10 μm.

EXAMPLE 9

[0060] KBM-503 (Shin-Etsu Chemical Co., Ltd.), DMDMS (Sigma-Aldrich Corporation), ethylene glycol (Sigma-Aldrich Corporation) and distilled water were mixed at a ratio of 435 g:90 g:104 g:30 g (1.75 mol:0.75 mol:1.688 mol:1.688 mol), the resulting mixture was injected into a 1,000 mL double-jacket reactor, a sodium hydroxide solution (NaOH 0.1 g in H.sub.2O 1 g) was added as a catalyst, and the mixture was stirred at 200 RPM with a mechanical stirrer at 90° C. for 8 hours using a thermostat. Then, the resulting mixture was diluted with 2-butanone to realize a solid content of 50 wt %, and was then filtered through a 0.45 μm Teflon filter to obtain a siloxane resin. The molecular weight of the resin was measured using GPC, and the result showed that the resin had a number average molecular weight of 1,079, a weight average molecular weight of 2,016, and a polydispersity index (PDI, Mw/Mn) of 1.86. Next, a resin composition for coating was prepared in the same manner as in Example 1, and a polyimide film was coated therewith to prepare a coating film with a thickness of 10 μm.

EXAMPLE 10

[0061] KBM-403 (Shin-Etsu Chemical Co., Ltd.), TEMS (Sigma-Aldrich Corporation), DMDMS (Sigma-Aldrich Corporation) and distilled water were mixed at a ratio of 414 g:67 g:45 g:64 g (1.75 mol:0.375 mol:0.375 mol:3.56 mol), the resulting mixture was injected into a 1,000 mL double-jacket reactor, a sodium hydroxide solution (NaOH 0.1 g in H.sub.2O 1 g) was added as a catalyst, and the mixture was stirred at 200 RPM with a mechanical stirrer at 90° C. for 8 hours using a thermostat. Then, the resulting mixture was diluted with 2-butanone to realize a solid content of 50 wt %, and was then filtered through a 0.45 μm Teflon filter to obtain a siloxane resin. The molecular weight of the resin was measured using GPC, and the result showed that the resin had a number average molecular weight of 3,863, a weight average molecular weight of 6,528, and a polydispersity index (PDI, Mw/Mn) of 1.69. Next, a resin composition for coating was prepared in the same manner as in Example 1, and a polyimide film was coated therewith to prepare a coating film with a thickness of 10 μm.

EXAMPLE 11

[0062] KBM-403 (Shin-Etsu Chemical Co., Ltd.), TEMS (Sigma-Aldrich Corporation), DMDMS (Sigma-Aldrich Corporation), and distilled water were mixed at a ratio of 414 g:89 g:30 g:65 g (1.75 mol:0.5 mol:0.25 mol:3.625 mol), the resulting mixture was injected into a 1,000 mL double-jacket reactor, a sodium hydroxide solution (NaOH 0.1 g in H.sub.2O 1 g) was added as a catalyst, and the mixture was stirred at 200 RPM with a mechanical stirrer at 90° C. for 8 hours using a thermostat. Then, the resulting mixture was diluted with 2-butanone to realize a solid content of 50 wt %, and was then filtered through a 0.45 μm Teflon filter to obtain a siloxane resin. The molecular weight of the resin was measured using GPC, and the result showed that the resin had a number average molecular weight of 4,174, a weight average molecular weight of 7,054, and a polydispersity index (PDI, Mw/Mn) of 1.69. Next, a resin composition for coating was prepared in the same manner as in Example 1, and a polyimide film was coated therewith to prepare a coating film with a thickness of 10 μm.

EXAMPLE 12

[0063] KBM-403 (Shin-Etsu Chemical Co., Ltd.), TEMS (Sigma-Aldrich Corporation), DMDMS (Sigma-Aldrich Corporation), ethylene glycol (Sigma-Aldrich Corporation) and distilled water were mixed at a ratio of 414 g:67 g:45 g:110 g: 32 g (1.75 mol:0.375 mol:0.375 mol:1.78 mol:1.78 mol), the resulting mixture was injected into a 1,000 mL double-jacket reactor, a sodium hydroxide solution (NaOH 0.1 g in H.sub.2O 1 g) was added as a catalyst, and the mixture was stirred at 200 RPM with a mechanical stirrer at 90° C. for 8 hours using a thermostat. Then, the resulting mixture was diluted with 2-butanone to realize a solid content of 50 wt %, and was then filtered through a 0.45 μm Teflon filter to obtain a siloxane resin. The molecular weight of the resin was measured using GPC, and the result showed that the resin had a number average molecular weight of 1,119, a weight average molecular weight of 1,835, and a polydispersity index (PDI, Mw/Mn) of 1.64. Next, a resin composition for coating was prepared in the same manner as in Example 1, and a polyimide film was coated therewith to prepare a coating film with a thickness of 10 μm.

EXAMPLE 13

[0064] The process was performed in the same manner as in Example 11, except that KBM-403 (Shin-Etsu Chemical Co., Ltd.), TEMS (Sigma-Aldrich Corporation), DMDMS (Sigma-Aldrich Corporation) and distilled water were mixed at a ratio of 414 g:12 g:82 g:61 g (1.75 mol:0.068 mol : 0.682 mol:3.409 mol).

EXAMPLE 14

[0065] The process was performed in the same manner as in Example 9, except that KBM-503 (Shin-Etsu Chemical Co., Ltd.), DMDMS (Sigma-Aldrich Corporation), ethylene glycol (Sigma-Aldrich Corporation) and distilled water were mixed at a ratio of 435 g:90 g:10.8 g:57.6 g (1.75 mol : 0.75 mol:0.175 mol:3.2 mol).

COMPARATIVE EXAMPLE 1

[0066] KBM-403 (Shin-Etsu Chemical Co., Ltd.) and distilled water were mixed at a ratio of 591 g:67.5 g (2.50 mol : 3.75 mol), the resulting mixture was injected into a 1,000 mL double-jacket reactor, a sodium hydroxide solution (NaOH 0.1 g in H.sub.2O 1g) was added as a catalyst, and the mixture was stirred at 200 RPM with a mechanical stirrer at 90° C. for 8 hours using a thermostat. Then, the resulting mixture was diluted with 2-butanone to realize a solid content of 50 wt %, and was then filtered through a 0.45 μm Teflon filter to obtain a siloxane resin. The molecular weight of the resin was measured using GPC, and the result showed that the resin had a number average molecular weight of 5,136, a weight average molecular weight of 16,486, and a polydispersity index (PDI, Mw/Mn) of 3.21. Next, a resin composition for coating was prepared in the same manner as in Example 1, and a polyimide film was coated therewith to prepare a coating film with a thickness of 10 μm.

COMPARATIVE EXAMPLE 2

[0067] KBM-503 (Shin-Etsu Chemical Co., Ltd.) and distilled water were mixed at a ratio of 621 g:67.5 g (2.50 mol : 3.75 mol), the resulting mixture was injected into a 1,000 mL double-jacket reactor, a sodium hydroxide solution (NaOH 0.1 g in H.sub.2O 1 g) was added as a catalyst, and the mixture was stirred at 200 RPM with a mechanical stirrer at 90° C. for 8 hours using a thermostat. Then, the resulting mixture was diluted with 2-butanone to realize a solid content of 50 wt %, and was then filtered through a 0.45 μm Teflon filter to obtain a siloxane resin. The molecular weight of the resin was measured using GPC, and the result showed that the resin had a number average molecular weight of 4,927, a weight average molecular weight of 16,456, and a polydispersity index (PDI, Mw/Mn) of 3.34. Next, a resin composition for coating was prepared in the same manner as in Example 1, and a polyimide film was coated therewith to prepare a coating film with a thickness of 10 μm.

COMPARATIVE EXAMPLE 3

[0068] KBM-403 (Shin-Etsu Chemical Co., Ltd.), TEOS (Sigma-Aldrich Corporation) and distilled water were mixed at a ratio of 414 g:156 g:74 g (1.75 mol:0.75 mol:4.125 mol), the resulting mixture was injected into a 1,000 mL double-jacket reactor, a sodium hydroxide solution (NaOH 0.1 g in H.sub.2O 1 g) was added as a catalyst, and the mixture was stirred at 200 RPM with a mechanical stirrer at 90° C. for 8 hours using a thermostat. Then, the resulting mixture was diluted with 2-butanone to realize a solid content of 50 wt %, and was then filtered through a 0.45 μm Teflon filter to obtain a siloxane resin. The molecular weight of the resin was measured using GPC, and the result showed that the resin had a number average molecular weight of 3,339, a weight average molecular weight of 21,370, and a polydispersity index (PDI, Mw/Mn) of 6.4. Next, a resin composition for coating was prepared in the same manner as in Example 1, and a polyimide film was coated therewith to prepare a coating film with a thickness of 10 μm.

MEASUREMENT EXAMPLE

[0069] The physical properties of the prepared coating films of Examples and Comparative examples were evaluated in accordance with the following methods, and the results are shown in Table 1 below.

[0070] (1) Surface hardness: pencil hardness was measured at a rate of 180 ram/min under a load of 1 kgf in accordance with ASTM D3363 using a pencil hardness tester manufactured by IMOTO (Japan).

[0071] (2) Curl: when a sample was cut into a square having a size of 100 mm×100 mm and placed on a flat plane, the maximum distance from the bottom to the edge was measured.

[0072] (3) Scratch resistance: A film cut into a rectangle 20 cm×5 cm in size was fixed using an adhesive tape (3M) such that a coating surface faced upwards, and whether or not scratching occurred was observed when a rod wrapped with #0000 (LIBERON) nonwoven fabric was reciprocated on the flat plane 10 times at 45 rpm under a load of 1.5 kgf. The case where scratching occurred was determined to be “NG”, and the case where no scratching occurred was determined to be “good”.

[0073] (4) Bending property (bendability): the final films prepared in accordance with Examples and Comparative Examples were cut into rectangles having a size of 50 mm×100 mm. Silver was deposited to about 100 nm on the upper surface of the coating layer to form a silver nano thin film, the point at which conductivity was lost was detected while simultaneously monitoring conductivity and decreasing the radius of curvature of the final films by 0.1R from 20R (R=mm) using a radial mode of a bending tester (JIRBT-620-2, Juniltech), and the detected point was taken as “bending property (crack)”.

[0074] (5) Transmittance and haze: The final films produced in accordance with Examples and Comparative Examples were cut into squares having a size of 50 mm×50 mm, and the transmittance and haze thereof were measured five times in accordance with ASTM D1003 using a haze meter (Model: HM-150) manufactured by MURAKAMI Co., and the average of the five values was calculated.

TABLE-US-00001 TABLE 1 Bending Trans- Surface Curl Scratch property mittance Haze hardness (mm) resistance (R) (%) (%) Ex. 1 5H 0 Good 1.9 91.5 1.0 Ex. 2 5H 0 Good 1.5 91.5 1.0 Ex. 3 5H 0 Good 3.0 91.5 1.0 Ex. 4 5H 5 Good 2.2 91.5 1.0 Ex. 5 5H 3 Good 2.0 91.5 1.0 Ex. 6 5H 0 Good 1.3 91.5 1.0 Ex. 7 5H 0 Good 1.2 91.5 1.0 Ex. 8 5H 5 Good 1.6 91.5 1.0 Ex. 9 5H 5 Good 1.4 91.5 1.0 Ex. 10 5H 0 Good 1.7 91.5 1.0 Ex. 11 5H 0 Good 1.8 91.5 1.0 Ex. 12 5H 0 Good 1.1 91.5 1.0 Ex. 13 5H 0 Good 1.5 91.5 1.0 Ex. 14 5H 4 Good 1.8 91.5 1.0 Comp. Ex. 1 4H 50 NG 3.5 91.5 1.0 Comp. Ex. 2 5H 110 Good 5.1 91.5 1.0 Comp. Ex. 3 5H 90 Good 3.8 91.5 1.0

[0075] As can be seen from Table 1, Comparative Examples 1 to 3, in which an alkoxysilane having a T structure or an alkoxysilane having a D-structure is not used for the synthesis of a siloxane resin, have a radius of curvature (R) higher than 3.0 mm, thus exhibiting significantly lowered flexibility or considerably low curling properties compared to Examples 1 to 14.

[0076] In particular, when comparing Comparative Example 1 using KBM-403 including an epoxy reactive group with Example 3 using KBM-403 in the same amount, it can be seen that Example 3 containing an alkoxysilane having a D structure exhibits improved hardness, curling property, and bending property compared to Comparative Example 1.

[0077] In addition, when comparing Comparative Example 2 using KBM-503, containing an acrylic reactive group, with Examples 4, 5, 8, 9 and 14, containing an alkoxysilane or diol, it can be seen that Examples 4, 5, 8, 9 and 14 have better pencil hardness, curling property, scratch resistance and flexibility.

[0078] In addition, among Examples, Examples 2, 5, 7 and 9, containing an alkoxysilane having a D structure, have better flexibility than Examples 1, 4, 6 and 8, containing an alkoxysilane having a T structure.

[0079] In addition, among Examples, Examples 1, 2, 6 and 7 using KBM-403 containing an epoxy reactive group have better curl and bending properties than Examples 4, 5, 8 and 9 using KBM-503 containing an acrylic reactive group.

[0080] In addition, among Examples, Examples 6 to 9 and 12 containing a diol have a better bending property than Examples containing no diol.

[0081] As can be seen from Examples described above, the resin composition for coating according to the present disclosure is capable of securing flexibility of the molecular bond and thus maximizing curling property and flexibility during curing without deterioration in surface hardness by introducing dialkoxysilane, having a silane D structure, and trialkoxysilane, having a silane T structure, into the synthesis of the siloxane resin.

INDUSTRIAL APPLICABILITY

[0082] The present disclosure is applicable to a transparent polymer film that can be extensively utilized as a core material in the fields of optical, transparent and flexible displays.