Flexible plastic substrate and display device including same

1. A flexible plastic substrate comprising

a film comprising a poly(amide-imide) copolymer; and

a hard coating layer disposed on a first surface of the film,

wherein the hard coating layer comprises a crosslinked siloxane copolymer wherein the crosslinked siloxane copolymer comprises a cured product of a siloxane copolymer represented by at least one of Chemical Formula 1, Chemical Formula 2, or Chemical Formula 3:

(R 1 SiO 3/2 ) x (R 2 R 3 SiO 2/2 ) y   Chemical Formula 1

wherein, in Chemical Formula 1,

R 1 is a cross-linkable functional group or a hydrocarbyl group substituted with a cross-linkable functional group,

R 2 and R 3 are each independently hydrogen, a cross-linkable functional group, a hydrocarbyl group substituted with a cross-linkable functional group, a substituted or unsubstituted C1 to C20 alkyl group, or a substituted or unsubstituted C5 to C20 cycloalkyl group, provided that at least one of R 2 and R 3 is a substituted or unsubstituted C1 to C20 alkyl group, and

0<x<1, 0<y<1, and x+y=1,

(R 1 SiO 3/2 ) x (R 4 SiO 3/2 ) z   Chemical Formula 2

wherein, in Chemical Formula 2,

R 1 is a cross-linkable functional group or a hydrocarbyl group substituted with a cross-linkable functional group;

R 4 is an ultraviolet light absorbing functional group or a C1 to C20 hydrocarbyl group substituted with an ultraviolet light absorbing functional group; and

0<x<1, 0<z<1, and x+z=1,

(R 1 SiO 3/2 ) x (R 2 R 3 SiO 2/2 ) y (R 4 SiO 3/2 ) z   Chemical Formula 3

wherein in Chemical Formula 3,

R 1 is a cross-linkable functional group or a hydrocarbyl group substituted with a cross-linkable functional group;

R 2 and R 3 are each independently hydrogen, a cross-linkable functional group, a hydrocarbyl group substituted with a cross-linkable functional group, a substituted or unsubstituted C1 to C20 alkyl group, or a substituted or unsubstituted C5 to C20 cycloalkyl group, provided that at least one of R 2 and R 3 is a substituted or unsubstituted C1 to C20 alkyl group;

R 4 is an ultraviolet light absorbing functional group or a C1 to C20 hydrocarbyl group substituted with an ultraviolet light absorbing functional group; and

0<x<1, 0<y<1, 0<z<1, and x+y+z=1, and

wherein the flexible plastic substrate has

a pencil hardness of greater than or equal to 2H under a vertical load of 1 kilogram according to ASTM D3363,

a total light transmittance of greater than or equal to about 89% in a wavelength region of 350 nanometers to 750 nanometers.

2. The flexible plastic substrate of claim 1 , wherein the cross-linkable functional group is a (meth)acrylate group, an epoxy group, an oxetanyl group, or a combination thereof.

3. The flexible plastic substrate of claim 1 , wherein the ultraviolet light absorbing functional group is a substituted or unsubstituted benzotriazole group, a substituted or unsubstituted benzophenone group, a substituted or unsubstituted hydroxybenzophenone group, a substituted or unsubstituted triazine group, a substituted or unsubstituted salicylate group, a substituted or unsubstituted cyanoacrylate group, a substituted or unsubstituted oxanilide group, a substituted or unsubstituted hydroxyphenyltriazine group, a substituted or unsubstituted hydroxyphenylbenzotriazole group, a substituted or unsubstituted hydroxyphenylbenzophenone group, or a combination thereof.

4. The flexible plastic substrate of claim 1 , wherein the siloxane copolymer represented by Chemical Formula 1 is further represented by at least one of Chemical Formulae 1-1 to 1-9:

(EcSiO 3/2 ) x (EcMeSiO 2/2 ) y   Chemical Formula 1-1

(EcSiO 3/2 ) x ((Me) 2 SiO 2/2 ) y   Chemical Formula 1-2

(EcSiO 3/2 ) x (GpMeSiO 2/2 ) y   Chemical Formula 1-3

(GpSiO 3/2 ) x (EcMeSiO 2/2 ) y   Chemical Formula 1-4

(GpSiO 3/2 ) x ((Me) 2 SiO 2/2 ) y   Chemical Formula 1-5

(GpSiO 3/2 ) x (GpMeSiO 2/2 ) y   Chemical Formula 1-6

(OpSiO 3/2 ) x (EcMeSiO 2/2 ) y   Chemical Formula 1-7

(OpSiO 3/2 ) x ((Me) 2 SiO 2/2 ) y   Chemical Formula 1-8

(OpSiO 3/2 ) x (GpMeSiO 2/2 ) y   Chemical Formula 1-9

wherein, in Chemical Formulae 1-1 to 1-9, Ec is a (3,4-epoxycyclohexyl)ethyl group, Me is a methyl group, Gp is a 3-glycidoxypropyl group, Op is a 3-oxetanylpropyl group, 0<x<1, 0<y<1, and x+y=1.

5. The flexible plastic substrate of claim 1 , wherein the siloxane copolymer represented by Chemical Formula 2 is further represented by at least one of Chemical Formulae 2-1 to 2-12:

(EcSiO 3/2 ) x (R a SiO 3/2 ) z   Chemical Formula 2-1

(EcSiO 3/2 ) x (R b SiO 3/2 ) z   Chemical Formula 2-2

(EcSiO 3/2 ) x (R c SiO 3/2 ) z   Chemical Formula 2-3

(EcSiO 3/2 ) x (R d SiO 3/2 ) z   Chemical Formula 2-4

(GpSiO 3/2 ) x (R a SiO 3/2 ) z   Chemical Formula 2-5

(GpSiO 3/2 ) x (R b SiO 3/2 ) z   Chemical Formula 2-6

(GpSiO 3/2 ) x (R c SiO 3/2 ) z   Chemical Formula 2-7

(GpSiO 3/2 ) x (R d SiO 3/2 ) z   Chemical Formula 2-8

(OpSiO 3/2 ) x (R a SiO 3/2 ) z   Chemical Formula 2-9

(OpSiO 3/2 ) x (R b SiO 3/2 ) z   Chemical Formula 2-10

(OpSiO 3/2 ) x (R c SiO 3/2 ) z   Chemical Formula 2-11

(OpSiO 3/2 ) x (R d SiO 3/2 ) z   Chemical Formula 2-12

wherein, in Chemical Formulae 2-1 to 2-12, Ec is a (3,4-epoxycyclohexyl)ethyl group, Gp is a 3-glycidoxypropyl group, Op is a 3-oxetanylpropyl group, R a is represented by Chemical Formula i, R b is represented by Chemical Formula ii, R c is represented by Chemical Formula iii, R d is represented by Chemical Formula iv, 0<x<1, 0<z<1, and x+z=1:

wherein in Chemical Formula i to Chemical Formula iv, * indicates a linking point.

6. The flexible plastic substrate of claim 1 , wherein the siloxane copolymer represented by Chemical Formula 3 is further represented by at least one of Chemical Formulae 3-1 to 3-36:

(EcSiO 3/2 ) x (EcMeSiO 2/2 ) y (R a SiO 3/2 ) z   Chemical Formula 3-1

(EcSiO 3/2 ) x (EcMeSiO 2/2 ) y (R b SiO 3/2 ) z   Chemical Formula 3-2

(EcSiO 3/2 ) x (EcMeSiO 2/2 ) y (R c SiO 3/2 ) z   Chemical Formula 3-3

(EcSiO 3/2 ) x (EcMeSiO 2/2 ) y (R d SiO 3/2 ) z   Chemical Formula 3-4

(EcSiO 3/2 ) x ((Me) 2 SiO 2/2 ) y (R a SiO 3/2 ) z   Chemical Formula 3-5

(EcSiO 3/2 ) x ((Me) 2 SiO 2/2 ) y (R b SiO 3/2 ) z   Chemical Formula 3-6

(EcSiO 3/2 ) x ((Me) 2 SiO 2/2 ) y (R c SiO 3/2 ) z   Chemical Formula 3-7

(EcSiO 3/2 ) x ((Me) 2 SiO 2/2 ) y (R d SiO 3/2 ) z   Chemical Formula 3-8

(EcSiO 3/2 ) x (GpMeSiO 2/2 ) y (R a SiO 3/2 ) z   Chemical Formula 3-9

(EcSiO 3/2 ) x (GpMeSiO 2/2 ) y (R b SiO 3/2 ) z   Chemical Formula 3-10

(EcSiO 3/2 ) x (GpMeSiO 2/2 ) y (R c SiO 3/2 ) z   Chemical Formula 3-11

(EcSiO 3/2 ) x (GpMeSiO 2/2 ) y (R d SiO 3/2 ) z   Chemical Formula 3-12

(GpSiO 3/2 ) x (EcMeSiO 2/2 ) y (R a SiO 3/2 ) z   Chemical Formula 3-13

(GpSiO 3/2 ) x (EcMeSiO 2/2 ) y (R b SiO 3/2 ) z   Chemical Formula 3-14

(GpSiO 3/2 ) x (EcMeSiO 2/2 ) y (R c SiO 3/2 ) z   Chemical Formula 3-15

(GpSiO 3/2 ) x (EcMeSiO 2/2 ) y (R d SiO 3/2 ) z   Chemical Formula 3-16

(GpSiO 3/2 ) x ((Me) 2 SiO 2/2 ) y (R a SiO 3/2 ) z   Chemical Formula 3-17

(GpSiO 3/2 ) x ((Me) 2 SiO 2/2 ) y (R b SiO 3/2 ) z   Chemical Formula 3-18

(GpSiO 3/2 ) x ((Me) 2 SiO 2/2 ) y (R c SiO 3/2 ) z   Chemical Formula 3-19

(GpSiO 3/2 ) x ((Me) 2 SiO 2/2 ) y (R d SiO 3/2 ) z   Chemical Formula 3-20

(GpSiO 3/2 ) x (GpMeSiO 2/2 ) y (R a SiO 3/2 ) z   Chemical Formula 3-21

(GpSiO 3/2 ) x (GpMeSiO 2/2 ) y (R b SiO 3/2 ) z   Chemical Formula 3-22

(GpSiO 3/2 ) x (GpMeSiO 2/2 ) y (R c SiO 3/2 ) z   Chemical Formula 3-23

(GpSiO 3/2 ) x (GpMeSiO 2/2 ) y (R d SiO 3/2 ) z   Chemical Formula 3-24

(OpSiO 3/2 ) x (EcMeSiO 2/2 ) y (R a SiO 3/2 ) z   Chemical Formula 3-25

(OpSiO 3/2 ) x (EcMeSiO 2/2 ) y (R b SiO 3/2 ) z   Chemical Formula 3-26

(OpSiO 3/2 ) x (EcMeSiO 2/2 ) y (R c SiO 3/2 ) z   Chemical Formula 3-27

(OpSiO 3/2 ) x (EcMeSiO 2/2 ) y (R d SiO 3/2 ) z   Chemical Formula 3-28

(OpSiO 3/2 ) x ((Me) 2 SiO 2/2 ) y (R a SiO 3/2 ) z   Chemical Formula 3-29

(OpSiO 3/2 ) x ((Me) 2 SiO 2/2 ) y (R b SiO 3/2 ) z   Chemical Formula 3-30

(OpSiO 3/2 ) x ((Me) 2 SiO 2/2 ) y (R c SiO 3/2 ) z   Chemical Formula 3-31

(OpSiO 3/2 ) x ((Me) 2 SiO 2/2 ) y (R d SiO 3/2 ) z   Chemical Formula 3-32

(OpSiO 3/2 ) x (GpMeSiO 2/2 ) y (R a SiO 3/2 ) z   Chemical Formula 3-33

(OpSiO 3/2 ) x (GpMeSiO 2/2 ) y (R b SiO 3/2 ) z   Chemical Formula 3-34

(OpSiO 3/2 ) x (GpMeSiO 2/2 ) y (R c SiO 3/2 ) z   Chemical Formula 3-35

(OpSiO 3/2 ) x (GpMeSiO 2/2 ) y (R d SiO 3/2 ) z   Chemical Formula 3-36

wherein, in Chemical Formulae 3-1 to 3-36, Ec is a 3,4-epoxycyclohexylethyl group, Me is a methyl group, Gp is a 3-glycidoxypropyl group, Op is a 3-oxetanylpropyl group, R a is represented by Chemical Formula i, R b is represented by Chemical Formula ii, R c is represented by Chemical Formula iii, R d is represented by Chemical Formula iv, 0<x<1, 0<y<1, 0<z<1, and x+y+z=1:

wherein in Chemical Formula i to Chemical Formula iv, * indicates a linking point.

7. The flexible plastic substrate of claim 1 , wherein the hard coating layer further comprises a nanoparticle.

8. The flexible plastic substrate of claim 7 , wherein the nanoparticle comprises silica, titania, barium titanate, zirconia, barium sulfate, alumina, hafnium oxide, or a combination thereof.

9. The flexible plastic substrate of claim 1 , wherein the hard coating layer further comprises a colorant having a maximum visible absorption peak at a wavelength of greater than or equal to 570 nanometers.

10. The flexible plastic substrate of claim 1 , further comprising a rear coating layer disposed on a second surface of the film opposite from the first surface on which the hard coating layer is disposed.

11. The flexible plastic substrate of claim 10 , wherein the rear coating layer comprises a colorant having a maximum visible absorption peak at a wavelength of greater than or equal to 570 nanometers.

12. The flexible plastic substrate of claim 10 , wherein the rear coating layer comprises a (meth)acrylate polymer, a polycaprolactone, a urethane-(meth)acrylate copolymer, polyrotaxane, an epoxy resin, perfluoropolyether, a crosslinked or uncrosslinked siloxane copolymer, or a combination thereof.

13. The flexible plastic substrate of claim 10 , wherein a thickness of the rear coating layer ranges from about 30 nanometers to about 300 nanometers.

14. The flexible plastic substrate of claim 1 , wherein a thickness of the poly(amide-imide) copolymer film ranges from about 10 micrometers to about 200 micrometers.

15. The flexible plastic substrate of claim 1 , wherein a thickness of the hard coating layer ranges from about 5 micrometers to about 50 micrometers.

16. The plastic substrate of claim 1 , wherein the poly(amide-imide) copolymer is a product of a reaction between a tetracarboxylic acid dianhydride represented by Chemical Formula 6, a diamine represented by Chemical Formula 7, and a dicarboxylic acid derivative represented by Chemical Formula 9:

wherein, in Chemical Formula 6,

R 10 is a single bond, a substituted or unsubstituted C3 to C10 cycloalkylene group, a substituted or unsubstituted C6 to C15 arylene group, —O—, —S—, —C(═O)—, —CH(OH)—, —S(═O) 2 —, —Si(CH 3 ) 2 —, —(CH 2 ) p —, —(CF 2 ) q —, —C(C n H 2n+1 ) 2 —, —C(C n F 2n+1 ) 2 —, —(CH 2 ) p —C(C n H 2n+1 ) 2 —(CH 2 ) q —, —(CH 2 ) p —C(C n F 2n+1 ) 2 —(CH 2 ) q —, or —C(═O)NH—, wherein 1≤n≤10, 1≤p≤10, and 1≤q≤10,

R 11 and R 12 are each the same or different and are independently a halogen, a hydroxy group, a substituted or unsubstituted C1 to C10 aliphatic group, a substituted or unsubstituted C6 to C20 aryl group, a group of the formula —OR 201 wherein R 201 is a C1 to C10 aliphatic group, or a group of the formula —SiR 210 R 211 R 212 wherein R 210 , R 211 , and R 212 are each the same or different and are independently hydrogen or a C1 to C10 aliphatic group, and

n1 and n2 are each the same or different and are independently an integer of 0 to 3,

NH 2 —R 13 —NH 2   Chemical Formula 7

wherein, in Chemical Formula 7, R 13 is represented by Chemical Formula 8:

wherein, in Chemical Formula 8,

L is a single bond, —CONH—, -Ph-CONH-Ph-, or —NHCO-Ph-CONH—, wherein Ph is a substituted or unsubstituted phenylene group, each linked to adjacent groups in an ortho, meta, or para configuration, and * is a point linked to nitrogen of an amino group,

X 1 —CO—R 14 —CO—X 2   Chemical Formula 9

wherein, in Chemical Formula 9,

X 1 and X 2 are each independently the same or different halogen, and R 14 is a phenylene group or a biphenylene group.

17. The flexible plastic substrate of claim 16 , wherein the tetracarboxylic acid dianhydride represented by Chemical Formula 6 is further represented by at least one of Chemical Formula 10 and Chemical Formula 11, the diamine represented by Chemical Formula 7 is 2,2′-bis(trifluoromethyl)benzidine, and the dicarboxylic acid derivative represented by Chemical Formula 9 is terephthaloyl chloride:

wherein, in Chemical Formula 10 and Chemical Formula 11, R 11 , R 12 , n 1 , and n 2 are each the same as defined in Chemical Formula 6.

18. The flexible plastic substrate of claim 17 , wherein the poly(amide-imide) copolymer is a product of a reaction between 2,2′-bis(trifluoromethyl)benzidine, the tetracarboxylic acid dianhydride represented by at least one of Chemical Formula 10 and Chemical Formula 11, and terephthaloyl chloride in a mole ratio of 1:0.1 to 0.5:0.5 to 0.9.

19. A display device comprising the flexible plastic substrate of claim 1 .