Composition for forming self-healing coating layer, coating layer and coating film

1. A composition for forming a self-healing coating layer, comprising:

a reversible covalent compound containing a (thio)urea functional group comprising one or more sterically hindered (thio)urea bonds and a (meth)acrylate-based or vinyl-based functional group bonded to the (thio)urea functional group;

an inorganic compound in which a (meth)acrylate-based functional group or a vinyl-based functional group is bonded through a (thio)urea functional group comprising a sterically hindered urea bond;

a photoinitiator; and

an organic solvent.

2. The composition for forming a self-healing coating layer according to claim 1 , wherein, in the sterically hindered (thio)urea bond, at least one nitrogen atom is substituted by a bulky functional group selected from the group consisting of a C2-C30 linear or branched alkyl group, a C2-C30 linear or branched alkenyl group, a C4-C30 cycloalkyl group, a C6-C30 aryl group, a heteroalkyl group, a cycloheteralkyl group, and a heteroaryl group.

3. The composition for forming a self-healing coating layer according to claim 1 , wherein the reversible covalent compound comprises a compound of the following Chemical Formula 1:

in the Chemical Formula 1,

L is an n-valent functional group derived from aliphatic, alicyclic or aromatic compounds;

n denotes the number of substitution of L, and is an integer of 1 to 20;

X is oxygen or sulfur;

Y is a direct bond, a C1-C30 linear or branched alkylene group, a C2-C30 linear or branched alkenylene group, a C4-C30 cycloalkylene group, a C6-C30 arylene group;

Z is a (meth)acrylate group or vinyl group;

R 1 is a bulky group selected from the group consisting of a C2-C30 linear or branched alkyl group, a C2-C30 linear or branched alkenyl group, a C4-C30 cycloalkyl group, a C6-C30 aryl group, a heteroalkyl group, a cycloheteralkyl group, and a heteroaryl group.

4. The composition for forming a self-healing coating layer according to claim 3 , wherein L is a 2 to 10 valent functional group derived from a C1-C20 linear or branched alkane, a C4-C20 cycloalkane, or a C6-C20 arene.

5. The composition for forming a self-healing coating layer according to claim 1 , further comprising one or more kinds of compounds selected from the group consisting of (meth)acrylate-based monomers, vinyl-based monomers and multifunctional (meth)acrylate-based compounds.

6. The composition for forming a self-healing coating layer according to claim 5 , wherein the multifunctional (meth)acrylate-based compound is one or more selected from the group consisting of multifunctional urethane acrylate, 9-ethyleneglycol diacrylate(9-EGDA), bisphenol A epoxy acrylate, polyether triacrylate, pentaerythritol tri/tetraacrylate(PETA), dipentaerythritol hexa-acrylate(DPHA), trimethylolpropane triacrylate(TMPTA) and hexamethylene diacrylate(HDDA).

7. The composition for forming a self-healing coating layer according to claim 5 , wherein the weight ratio of the reversible covalent compound to the total weight of the reversible covalent compound and one or more compounds selected from the group consisting of (meth)acrylate-based monomers, vinyl-based monomers and multifunctional (meth)acylate-based compounds is 5 wt % to 95 wt %.

8. The composition for forming a self-healing coating layer according to claim 1 , further comprising one or more polymer resins selected from the group consisting of urethane (meth)acrylate resin and hydroxyalkyl (meth)acrylate resin.

9. The composition for forming a self-healing coating layer according to claim 1 , wherein the photoinitiator comprises one or more compounds selected from the group consisting of an acetophenone-based compound, a biimidazole-based compound, a triazine-based compound and an oxime-based compound.

10. The composition for forming a self-healing coating layer according to claim 1 , further comprising inorganic filler.

11. The composition for forming a self-healing coating layer according to claim 1 , wherein the inorganic compound in which a (meth)acrylate-based functional group or a vinyl-based functional group is bonded through a (thio)urea functional group comprising a sterically hindered urea bond, comprises a silicon-based compound in which a (meth)acrylate-based functional group or a vinyl-based functional group is bonded through a (thio)urea functional group comprising a sterically hindered urea bond.

12. The composition for forming a self-healing coating layer according to claim 1 , wherein the inorganic compound in which a (meth)acrylate-based functional group or a vinyl-based functional group is bonded through a (thio)urea functional group comprising a sterically hindered urea bond, comprises a compound of the following Chemical Formula 2:

in the Chemical Formula 2,

X is oxygen or sulfur;

L and Y are respectively a direct bond, a C1-C30 linear or branched alkylene group, a C2-C30 linear or branched alkenylene group, a C4-C30 cycloalkylene group, a C6-C30 arylene group;

Z is a (meth)acrylate group or a vinyl group;

R 1 is a bulky group selected from the group consisting of a C2-C30 linear or branched alkyl group, a C2-C30 linear or branched alkenyl group, a C4-C30 cycloalkyl group, a C6-C30 aryl group, a heteroalkyl group, a cycloheteralkyl group, and a heteroaryl group;

R 2 is a C1-C10 linear or branched alkyl group, or a C1-C10 linear or branched alkoxy group;

p is an integer of 1 to 4, and p+q is 4.

13. A coating film comprising the cured product of the coating composition of claim 1 .

14. A coating film comprising:

a polymer resin in which a (meth)acrylate-based or vinyl-based main chain forms a cross link through a (thio)urea functional group comprising one or more sterically hindered (thio)urea bonds; and

an inorganic compound in which a (meth)acrylate-based functional group or a vinyl-based functional group is bonded through a (thio)urea functional group comprising a sterically hindered urea bond, dispersed in the polymer resin.

15. The coating film according to claim 14 , wherein the polymer resin further comprises polyurethane, urethane (meth)acrylate resin and hydroxyalkyl (meth)acrylate resin.

16. The coating film according to claim 14 , further comprising inorganic filler dispersed in the polymer resin.