Composition for coating comprising silsesquioxane polymer and flexible display film

Abstract

The present invention relates to a coating composition for a flexible display, a coating film prepared therefrom, and a display panel, the coating composition comprising a silsesquioxane polymer and capable of providing a thin film having excellent elongation and bending durability.

Description

Technical Field

[0001] The present invention relates to a coating composition containing a silsesquioxane polymer, a flexible display film including a coating coated with the above coating composition, and a display panel. Background Art

[0002] In recent years, the display market has been rapidly shifting from flat displays to flexible displays such as foldable and rollable ones. The transformation of flexible displays is rapidly advancing towards thinner, more flexible, and larger-sized display films, and recently related products have become a reality. In particular, in order to ensure the flexibility of the display, the thick glass material applied to the outermost layer is being replaced by thin film glass or plastic materials. Although thin film glass and plastic materials can increase the flexibility of the display, their surface physical properties are very fragile. Therefore, to overcome the surface physical property problems, the importance of coating materials has become increasingly prominent.

[0003] For the above reasons, there is currently an active research and development on coating materials that can meet the flexibility requirements of flexible displays and improve the surface physical properties to protect the surface of the display panel. The properties required for the outermost layer coating material of a flexible display include adhesion to the substrate, optical properties, flexibility, elongation, and film strength.

[0004] In Korean Patent Publication No. 10-2017-0122656, it is described that a coating is formed on an optical polyimide film by coating a mixture containing a silicon nitride compound, a thiol compound, a polyfunctional polyurethane (meth)acrylate containing cyclohexyl, a photoinitiator, inorganic nanoparticles, and a solvent, thereby improving the curling characteristics, hardness, and flexibility of the substrate. However, the above patent only describes the formation of a coating film by UV curing and does not describe the dispersion stability of the inorganic particles and the elongation after coating. Therefore, there may be problems such as poor stability of the composition, elongation after coating, and bending durability.

[0005] Therefore, there is an urgent need to develop a coating composition that can provide a coating having excellent elongation and bending durability while having optical properties and surface physical properties. Summary of the Invention

[0006] Problems to be Solved by the Invention

[0007] An object of the present invention is to provide a coating composition for a substrate for a flexible display, which has excellent elongation and bending durability in addition to having optical properties and surface physical properties.

[0008] Means for Solving the Problems

[0009] According to an embodiment of the present invention, there is provided a coating composition comprising: a silsesquioxane polymer comprising repeating units of the following Chemical Formula 1 and repeating units of the following Chemical Formula 2; and a linear polymer comprising a first reactive functional group reactive with the above silsesquioxane polymer:

[0010] [Chemical Formula 1]

[0011]

[0012] [Chemical Formula 2]

[0013]

[0014] In the above Chemical Formula 1 and Chemical Formula 2,

[0015] R1 is *-L1-R a , R2 is *-L2-R b , L1 and L2 each independently represent a direct bond, an alkylene group having 1 to 10 carbon atoms, an oxyalkylene group having 1 to 10 carbon atoms, or an alkyl ester having 1 to 10 carbon atoms, each L1, each L2, or L1 and L2 are the same or different, R a and R b are each independently a second reactive functional group, each R a , each R b or R a and R b are the same or different, R3 is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and n and m are each independently an integer from 1 to 100,000.

[0016] According to another aspect of the present invention, there is provided a coating film formed from the above silsesquioxane polymer and linear polymer.

[0017] According to still another aspect of the present invention, there is provided a flexible display film, which is a flexible display film including a substrate and a coating formed on the above substrate, and the above coating is formed from the above silsesquioxane polymer and linear polymer.

[0018] Advantages of the Invention

[0019] According to the present invention, when a coating composition prepared by mixing a silsesquioxane polymer and a linear-structured polymer having reactive functional groups is used, a coating having not only excellent optical properties and surface physical properties but also excellent elongation and bending durability can be formed. In particular, by introducing a predetermined compatibility functional group into the linear-structured polymer, the compatibility with the above silsesquioxane polymer is improved, and the adhesion to the substrate can also be imparted.

[0020] The composition of the present invention can be thermally cured or UV cured according to the initiator, and can exhibit excellent surface physical properties even without the additional addition of inorganic particles for improving surface physical properties such as hardness and scratch resistance. In addition, since the above inorganic particles are not contained, the stability of the composition can be improved.

[0021] As described above, the coating composition of the present invention has optical properties, surface physical properties, elongation, and bending durability, and thus can be applied as a coating on a substrate such as ultra-thin tempered glass (UTG), thereby providing a flexible display with excellent flexibility and bending properties. Detailed Description

[0022] Hereinafter, the present invention will be described in more detail, but this description is only for illustrative purposes and should not be construed as limiting the scope of the claims of the present invention.

[0023] In the present specification, "(sub)alkyl having 1 to 10 carbon atoms" means a straight-chain or branched-chain (sub)alkyl having 1 to 10 carbon atoms, and among them, the number of carbon atoms can be 1 to 6. Examples of the above (sub)alkyl include methyl(ene) group, ethyl(ene) group, n-propyl(ene) group, isopropyl(ene) group, n-butyl(ene) group, isobutyl(ene) group, and tert-butyl(ene) group.

[0024] In the present specification, "alkylene oxide having 1 to 10 carbon atoms" may refer to an alkylene having 1 to 10 carbon atoms connected to an ether represented by -O-, and among them, the definition of the alkylene having 1 to 10 carbon atoms is the same as described above.

[0025] In the present specification, "alkyl ester having 1 to 10 carbon atoms" may refer to an alkylene having 1 to 10 carbon atoms connected to an ester represented by -O-CO-, and among them, the definition of the alkylene having 1 to 10 carbon atoms is the same as described above.

[0026] In the present specification, "alkoxy having 1 to 20 carbon atoms" means a straight-chain or branched-chain alkoxy having 1 to 20 carbon atoms, and among them, the number of carbon atoms can be 1 to 15, 1 to 10, 1 to 6, or 1 to 3. Examples of the above alkoxy include methoxy, ethoxy, etc.

[0027] According to an embodiment of the present invention, the coating composition includes a silsesquioxane polymer including a repeating unit represented by the following Chemical Formula 1 and a repeating unit represented by the following Chemical Formula 2:

[0028] [Chemical Formula 1]

[0029]

[0030] [Chemical Formula 2]

[0031]

[0032] In the above Chemical Formula 1 and Chemical Formula 2, R1 is *-L1-R a , and R2 is *-L2-R b . In Chemical Formula 1, the above R1s may be the same or different. In addition, in Chemical Formula 2, the above R2s may also be the same or different.

[0033] The above L1 and L2 are each independently selected from the group consisting of a direct bond, an alkylene group having 1 to 10 carbon atoms, an oxyalkylene group having 1 to 10 carbon atoms, and an alkyl ester group having 1 to 10 carbon atoms. Each L1, each L2, or L1 and L2 may be the same or different. According to one embodiment, the above L1 and L2 are each independently selected from the group consisting of a direct bond, an alkylene group having 1 to 10 carbon atoms, and an oxyalkylene group having 1 to 10 carbon atoms. For example, the above L1 and L2 may be independently selected from the group consisting of a direct bond, a linear or branched alkylene group having 1 to 6 carbon atoms, and an oxyalkylene group having 1 to 6 carbon atoms.

[0034] The above R a and R b are each independently a second reactive functional group. Each R a , each R b or R a and R b may be the same or different. According to one embodiment, the above second reactive functional group may be an amino group, an acryloyl group, a methacryloyl group, a vinyl group, an epoxy group, or a thiol group. According to another embodiment, the above second reactive functional group may be an acryloyl group, a methacryloyl group, or an epoxy group. For example, R a and R b may be an epoxy group. According to one embodiment, the above R a and R b may be the same. According to one embodiment, the above second reactive functional group may be further substituted.

[0035] The above R3 is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. According to one embodiment, the above R3 may be a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. According to another embodiment, the above R3 may be a methyl group, an ethyl group, a n-propyl group, or an isopropyl group. By introducing the -OR3 group containing the above R3, the bonding strength and adhesion between the substrate and the composition can be improved. Especially in an organic substrate, covalent bonds can be formed with Si-OH and Si-O on the glass surface, thereby enhancing the bonding strength and adhesion to the substrate during coating.

[0036] Each of the above n and m is independently an integer from 1 to 100,000. The above n / m can be from 1 to 50. The adhesion property to the substrate can be adjusted by the ratio of n / m. The smaller the ratio of n / m, the better the adhesion to the substrate.

[0037] The repeating unit of the above Chemical Formula 1 and the repeating unit of the above Chemical Formula 2 can be arranged in a random or regular manner. According to one embodiment, the repeating unit of the above Chemical Formula 1 and the repeating unit of the above Chemical Formula 2 can be randomly arranged.

[0038] According to one embodiment, the silsesquioxane polymer containing the repeating unit of the above Chemical Formula 1 and the repeating unit of the above Chemical Formula 2 can be represented by the following chemical formula.

[0039]

[0040] In the above chemical formula, R1, R2 and R3 are the same as defined in Chemical Formulas 1 and 2, and R is a second reactive functional group, which can be, for example, an amino group, an acryloyl group, a methacryloyl group, a vinyl group, an epoxy group or a thiol group. According to one embodiment, the above R can be the same as R1 or R2, wherein R1 and R2 can be the same or different. For example, when R1 and R2 are the same, R, R1 and R2 can all be the same. When R1 and R2 are different, R can be the same as any one of R1 or R2, or a part of R is the same as R1 and the other part is the same as R2.

[0041] According to one embodiment of the present invention, the coating composition contains a linear polymer containing a first reactive functional group that can react with the above silsesquioxane polymer. By including a linear structural polymer that can react with the silsesquioxane polymer, the present invention can improve elongation, bending durability, etc.

[0042] According to one embodiment, the above linear polymer can be a non-siloxane polymer. That is, the above linear polymer may not contain a siloxane unit in the main chain, but may further contain an organosilicon substituent in the side chain as needed.

[0043] According to one embodiment, the first reactive functional group in the above linear polymer that can react with the above silsesquioxane polymer can be an amino group, an acryloyl group, a methacryloyl group, a vinyl group, an epoxy group or a thiol group. According to another embodiment, the first reactive functional group of the above linear polymer can be an acryloyl group, a methacryloyl group or an epoxy group. For example, the above reactive functional group can be an epoxy group.

[0044] According to one embodiment, the above linear polymer may further comprise a compatibility functional group. The above compatibility functional group may impart compatibility with the above silsesquioxane polymer. In addition, the above compatibility functional group may impart not only compatibility with the above silsesquioxane polymer but also compatibility with the substrate. Specifically, according to one embodiment, the above compatibility functional group may be a hydroxyl group or an alkoxy group having 1 to 20 carbon atoms. For example, a hydroxyl group, a methoxy group, an ethoxy group, a propoxy group, or a butoxy group. According to one embodiment, the above compatibility functional group may have a polarity similar to the reactive functional groups (R a 、R b ) of the above silsesquioxane polymer, and the compatibility may be further improved by the similarity of the polarities. At this time, those skilled in the art will be able to clearly judge whether the polarities of the respective functional groups are similar based on common technical knowledge. According to one embodiment, the compatibility functional group of the above linear polymer may be the same as or of the same type of structure as the -OR3 group in the following Chemical Formula 2.

[0045] According to one embodiment, the above linear polymer may be a linear polymer comprising a repeating unit represented by the following Chemical Formula 3 and a repeating unit represented by the following Chemical Formula 4:

[0046] [Chemical Formula 3]

[0047]

[0048] [Chemical Formula 4]

[0049]

[0050] In the above Chemical Formula 3 and Chemical Formula 4, L3 and L4 are each independently selected from the group consisting of a direct bond, an alkylene group having 1 to 10 carbon atoms, a ketone, an ester, an oxyalkylene group having 1 to 10 carbon atoms, and an alkyl ester having 1 to 10 carbon atoms. R4 is a compatibility functional group providing compatibility with the above silsesquioxene polymer. R6 is a first reactive functional group that can react with the above silsesquioxene polymer. R5 and R7 are each independently selected from the group consisting of hydrogen, deuterium, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, and a first reactive functional group that can react with the above silsesquioxane polymer. a is an integer of 0 or 1 to 100000, b is an integer of 1 to 100000, and a / b is 0 to 100.

[0051] According to one embodiment, the above L3 and L4 may each independently be a methylene group, an ethylene group, an ether, an ester, an oxymethylene group, or an oxyethylene group.

[0052] According to one embodiment, the above R4 may have a similar polarity to the above R1 in the above Chemical Formula 1. According to another embodiment, the above R4 may be the same as or of the same type of structure as -OR3 in the above Chemical Formula 2.

[0053] According to one embodiment, the above R4 may be *-L5-R8 or *-L6-SiR9R 10 R 11 , where the above L5 and L6 may each independently be selected from the group consisting of a direct bond, an alkylene group having 1 to 10 carbon atoms, an oxyalkylene group having 1 to 10 carbon atoms, and an alkyl ester having 1 to 10 carbon atoms, and the above R8, R9, R 10 and R 11 may each independently be a hydroxyl group or an alkoxy group having 1 to 10 carbon atoms. According to one embodiment, the above L5 and L6 may each independently be selected from the group consisting of a direct bond, an alkylene group having 1 to 10 carbon atoms, and an oxyalkylene group having 1 to 10 carbon atoms. For example, the above L5 and L6 may each independently be selected from the group consisting of a direct bond, a linear or branched alkylene group having 1 to 6 carbon atoms, and an oxyalkylene group having 1 to 6 carbon atoms. According to one embodiment, the above R8, R9, R 10 and R 11 may each independently be a hydroxyl group or an alkoxy group having 1 to 20 carbon atoms, such as a hydroxyl group, a methoxy group, an ethoxy group, a propoxy group, or a butoxy group.

[0054] According to one embodiment, the above first reactive functional group may be an amino group, an acryloyl group, a methacryloyl group, a vinyl group, an epoxy group, or a thiol group. According to another embodiment, the above R6 may be an acryloyl group, a methacryloyl group, or an epoxy group. For example, the above R6 may be an epoxy group.

[0055] According to one embodiment, the above R5 and R7 may each independently be hydrogen or an alkyl group having 1 to 10 carbon atoms; or hydrogen or an alkyl group having 1 to 6 carbon atoms. For example, they may be hydrogen, a methyl group, an ethyl group, a n-propyl group, an isopropyl group, etc.

[0056] According to one embodiment, the above a may be 0. According to another embodiment, the above a may be an integer from 1 to 100000.

[0057] According to one embodiment, a / b may be 0 because a is 0. According to another embodiment, a / b may be from 1 / 100 to 100. Specifically, a / b may be from 1 / 50 to 1, or from 1 to 50, or from 1 / 20 to 1, or from 1 to 20, or from 1 / 10 to 1 / 2. The compatibility with the silsesquioxane polymer can be adjusted by the ratio of a / b, so a / b can be appropriately adjusted as needed.

[0058] The repeating units of the above chemical formula 3 and the repeating units of the above chemical formula 4 may be arranged in a random or regular manner. According to one embodiment, the repeating units of the above chemical formula 3 and the repeating units of the above chemical formula 4 may be arranged randomly.

[0059] According to one embodiment, the weight ratio of the above silsesquioxane polymer and the above linear polymer may be from 10:1 to 1:10. Specifically, the above weight ratio may be from 10:1 to 1:1 or from 9:1 to 1:1. Specifically, the above weight ratio may be from 1:1 to 1:10 or from 1:1 to 1:9. As the proportion of the above linear polymer increases, the elongation, bending durability, etc. may be improved, but the physical properties such as hardness may be reduced. Therefore, the above ratio may be appropriately adjusted according to the characteristics required for the product.

[0060] According to one embodiment, in addition to the above silsesquioxane polymer and the above linear polymer, the above coating composition may further contain surface additives, initiators, solvents, etc.

[0061] According to one embodiment, the above coating composition may further contain an initiator. For the curing and post-reaction of the coating composition, as the above initiator, various types of initiators may be used according to the reactive functional groups of the silsesquioxane polymer and the linear polymer as the binder resin.

[0062] When introducing unsaturated hydrocarbons or the like into the second reactive functional group of the silsesquioxane polymer and the first reactive functional group of the linear polymer, a free radical initiator can be used. As the free radical initiator, trichloroacetophenone, diethoxyacetophenone, 1-phenyl-2-hydroxy-2-methylpropane-1-one, 1-hydroxycyclohexylphenyl ketone, 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropane-1-one, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, camphorquinone, etc. can be used. Photo radical initiators such as tert-butyl peroxymaleic acid, tert-butyl hydroperoxide, 2,4-dichlorobenzoyl peroxide, 1,1-di(t-butylperoxy)-3,3,5-trimethylcyclohexane, N-butyl-4,4'-di(tert-butylperoxy)valerate, and various mixtures thereof.

[0063] In addition, when the second reactive functional group of the silsesquioxane polymer and the first reactive functional group of the linear polymer contain epoxy or the like, as the (cationic) photopolymerization initiator, sulfonium such as triphenylsulfonium, diphenyl-4-(phenylthio)phenylsulfonium, etc.; iodonium such as diphenyliodonium, bis(dodecylphenyl)iodonium, etc.; diazonium such as benzenediazonium, etc.; 1-benzyl-2-cyanopyridinium, 1-(naphthylmethyl)-2-cyanopyridinium, etc. can be used. ammonium; (4-methylphenyl) [4- (2-methylpropyl) phenyl] - hexafluorophosphate iodonium, bis (4-t-butylphenyl) hexafluorophosphate iodonium, diphenyl hexafluorophosphate iodonium, diphenyl trifluoromethanesulfonium iodonium, triphenylsulfonium tetrafluoroborate, tri-p-tolylsulfonium hexafluorophosphate, tri-p-tolylsulfonium trifluoromethanesulfonate and (2,4-cyclopentadien-1-yl) [(1-methylethyl) phenyl] - iron (Fe) and other iron cations and BF4 - PF6 - 、SbF6 - etc. [BQ4] -Combinations of onium salts, where Q is a phenyl group substituted with at least two fluorine or trifluoromethyl groups.

[0064] In addition, as a thermal cationic initiator, various onium salts such as trifluorides, boron trifluoride ether complexes, boron trifluoride and other cationic or protonic acid catalysts, ammonium salts, phosphonium salts and sulfonium salts can be used without limitation, and methyltriphenylphosphonium bromide, ethyltriphenylphosphonium bromide, phenyltriphenylphosphonium bromide, etc. can also be used. The above initiators can also be added in various mixed forms and can also be used in combination with various radical initiators listed above.

[0065] In addition, according to the types of the second reactive functional groups of the above-mentioned silsesquioxane polymer and the first reactive functional groups of the linear polymer, ethylenediamine, triethylenetetramine, tetraethylenepentamine, 1,3-diaminopropane, dipropylenetriamine, 3-(2-aminoethyl)aminopropylamine, N,N'-bis(3-aminopropyl)ethylenediamine, 4,9-dioxadodecane-1,12-diamine, 4,7,10-trioxatridecane-1,13-diamine, hexamethylenediamine, 2-methylpentamethylenediamine, 1,3-bis(aminomethyl)cyclohexane, bis(4-aminocyclohexyl)methane, norbornenediamine, 1,2-diaminocyclohexane, etc. which are amine curing agents can also be used.

[0066] In addition, according to an embodiment of the present invention, the above coating composition may further contain a curing accelerator for promoting the above curing effect. The above curing accelerator can be triazine compounds such as aceto guanamine, benzo guanamine, 2,4-diamino-6-vinyl-s-triazine, etc., imidazole compounds such as imidazole, 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, vinylimidazole, 1-methylimidazole, etc., 1,5-diazabicyclo[4.3.0]nonene-5, 1,8-diazabicyclo[5.4.0]undecene-7, triphenylphosphine, diphenyl-p-tolylphosphine, tris(alkylphenyl)phosphine, tris(alkoxyphenyl)phosphine, ethyltriphenylphosphonium phosphate, tetrabutylphosphonium hydroxide, tetrabutylphosphonium acetate, tetrabutylphosphonium hydrogen difluoride, tetrabutylphosphonium dihydrogen trifluoride, etc. In addition, anhydride curing agents such as phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, maleic anhydride, tetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnorbornene anhydride, hydrogenated methylnorbornene anhydride, trialkyltetrahydrophthalic anhydride, dodecenylsuccinic anhydride, 2,4-diethylglutaric anhydride, etc. can also be widely used.

[0067] Further, according to an embodiment of the present invention, the coating composition may further contain a silicone additive or an acrylic additive as needed. Examples of the silicone additive include BYK-300, BYK-301, BYK-302, BYK-331, BYK-335, BYK-306, BYK-330, BYK-341, BYK-344, BYK-307, BYK-333, BYK-310, etc., and examples of the acrylic additive include BYK-340, BYK-350, BYK-352, BYK-354, BYK-355, BYK-356, BYK-358N, BYK-359, BYK-361N, BYK-380N, BYK-381, BYK-388, BYK-390, BYK-392, BYK-394, etc. By including the above silicone additive and acrylic additive, the flatness of the coating film surface can be further improved.

[0068] In addition, according to an embodiment of the present invention, the coating composition may further contain a solvent. The above solvent can make the coating operation easier by imparting and adjusting the fluidity of the coating composition and contribute to the uniform mixing of the overall composition. As the above solvent, alcohol solvents such as methanol, ethanol, isopropyl alcohol, butanol, Cellosolve (ethylene glycol monoethyl ether), lactate solvents, ketone solvents such as acetone, methyl isobutyl ethyl ketone, ethylene glycol solvents such as ethylene glycol, furan solvents such as tetrahydrofuran, and polar solvents such as dimethylformamide, dimethylacetamide, N-methyl-2-pyrrolidone can be used. In addition, various solvents such as hexane, cyclohexane, cyclohexanone, toluene, xylene, cresol, chloroform, dichlorobenzene, xylene, trimethylbenzene, pyridine, methylnaphthalene, nitromethane, acrylonitrile, dichloromethane, octadecylamine, aniline, dimethyl sulfoxide, benzyl alcohol can also be used, but are not limited thereto.

[0069] In addition, according to another embodiment of the present invention, a coating film formed of the above silsesquioxane polymer and the above linear polymer is provided. According to still another embodiment of the present invention, a method for preparing a coating film is provided, which includes the step of mixing the above silsesquioxane polymer and the above linear polymer. For the detailed description of the above silsesquioxane polymer and the above linear polymer, reference can be made to the foregoing content. The above coating film is formed by using the above silsesquioxane polymer and linear polymer according to the present invention, so that not only the optical properties or physical properties are improved, but also excellent properties may be exhibited in characteristics such as elongation and bending durability. In one example, the crack-strain value of the above coating film may be 4.0% or more. In another example, the number of bending times at which cracks occur in the bending performance evaluation of the above coating film may be 100,000 times or more. According to an embodiment, the above coating film can be used for flexible displays.

[0070] According to another embodiment of the present invention, a display panel is provided, which includes: a substrate; the coating film formed on one surface of the substrate; and a light-emitting element formed on the other surface of the substrate. For a detailed description of the coating film, reference may be made to the foregoing content. The substrate may be polyimide (PI), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polycarbonate (PC), or ultra-thin tempered glass (UTG), etc.

[0071] Hereinafter, in order to help understand the present invention, the present invention will be described in more detail with reference to preferred embodiments. The following embodiments are examples proposed for explaining the invention, and thus the protection scope of the present invention should not be limited thereto.

[0072] [Synthesis Example 1A: Synthesis of Silsesquioxane Polymer 1A]

[0073] (1) Preparation of Polymerization Catalyst

[0074] To adjust the alkalinity, a 25 wt% aqueous solution of tetramethylammonium and a 10% aqueous solution of potassium hydroxide were mixed to prepare a catalyst.

[0075] (2) Synthesis of Silsesquioxane Polymer 1A

[0076] In a dry flask equipped with a condenser and a stirrer, 10 g of distilled water and 100 g of methanol were mixed to prepare a solution, and then 23.63 g (0.1 mol) of 3-glycidoxypropyltrimethoxysilane was slowly added dropwise and stirred for 30 minutes. Subsequently, 5 g of a 0.36 wt% aqueous HCl solution was very slowly added dropwise to the above reaction solution to adjust the pH to acidic, and stirred for 1 hour to promote the hydrolysis reaction. At this time, the temperature was maintained at -4°C.

[0077] After that, 25 g of the separately prepared catalyst was added dropwise, the pH was adjusted to alkaline, and the temperature was raised to 45°C for a condensation reaction for 12 hours.

[0078] The silsesquioxane structure and solvent mixture obtained in the above reaction were extracted with distilled water to remove the catalyst and impurities. After confirming that the pH was neutral, the solvent was completely removed by a reduced-pressure vacuum method, and finally a silsesquioxane polymer (weight average molecular weight: 1800; in Chemical Formulas 1 and 2, n / m = 1) was obtained.

[0079] [Synthesis Example 1B: Synthesis of Silsesquioxane Polymer 1B]

[0080] Except that 23.63 g (0.1 mol) of 3-glycidoxypropyltrimethoxysilane was replaced with 24.84 g (0.1 mol) of 3-methacryloxypropyltrimethoxysilane, the silsesquioxane polymer (weight average molecular weight: 1,800; n / m = 1 in Chemical Formulas 1 and 2) was synthesized in the same manner as in Synthesis Example 1A.

[0081] [Synthesis Example 1C: Synthesis of Silsesquioxane Polymer 1C]

[0082] Except that 100 g of methanol was replaced with 70 g of methanol, the silsesquioxane polymer (weight average molecular weight: 2,500; n / m = 3 in Chemical Formulas 1 and 2) was synthesized in the same manner as in Synthesis Example 1A.

[0083] [Synthesis Example 1D: Synthesis of Silsesquioxane Polymer 1D]

[0084] Except that 100 g of methanol was replaced with 20 g of methanol, the silsesquioxane polymer (weight average molecular weight: 25,000; n / m = 70 in Chemical Formulas 1 and 2) was synthesized in the same manner as in Synthesis Example 1A.

[0085] [Synthesis Example 2A: Synthesis of Linear Polymer 2A]

[0086] 300 g of toluene, 300 g of acetonitrile, and 15 g of 2,2-azobis(2,4-dimethylvaleronitrile) were mixed to prepare a mixed solution, and then 24.84 g (0.1 mol) of 3-methacryloxypropyltrimethoxysilane and 127.94 g (0.9 mol) of glycidyl methacrylate were slowly added dropwise to the prepared mixed solution to prepare a reaction solution.

[0087] The above reaction solution was transferred to a dry flask equipped with a condenser and a stirrer, and nitrogen gas was introduced for nitrogen replacement. While stirring the reaction solution in the reactor, the internal temperature was raised to 70°C, and then a polymerization reaction was carried out for 12 hours.

[0088] The linear polymer and solvent mixture obtained from the above reaction were precipitated in a 1:1 mixed solution of water and ethanol, washed with the same mixed solution, and dried at 80 °C for 12 hours, thereby obtaining a linear polymer (weight-average molecular weight: 10,000; in Chemical Formulas 3 and 4, a:b = 1:9). In the above linear polymer, the ratio of the repeating unit containing a trimethoxy functional group (compatible functional group) to the repeating unit containing a glycidyl functional group (reactive functional group) is 1:9.

[0089] [Synthesis Example 2B: Synthesis of Linear Polymer 2B]

[0090] 300 g of toluene, 300 g of acetonitrile, and 15 g of 2,2-azobis(2,4-dimethylvaleronitrile) were mixed to prepare a mixed solution, and then 142.15 g (1 mol) of glycidyl methacrylate was slowly added dropwise to the prepared mixed solution to prepare a reaction solution.

[0091] The above reaction solution was transferred to a dry flask equipped with a condenser and a stirrer, and nitrogen was introduced for nitrogen replacement. While stirring the reaction solution in the reactor, the internal temperature was raised to 70 °C, and then a polymerization reaction was carried out for 12 hours.

[0092] The linear polymer and solvent mixture obtained from the above reaction were precipitated in a 1:1 mixed solution of water and ethanol, washed with the same mixed solution, and dried at 80 °C for 12 hours, thereby obtaining a linear polymer (weight-average molecular weight: 10,000; a = 0 in Chemical Formula 3) containing a repeating unit having a glycidyl functional group (reactive functional group).

[0093] [Synthesis Example 2C: Synthesis of Linear Polymer 2C]

[0094] 100 g of tetrahydrofuran and 10 g of IRGACURE 290 (BASF) were mixed to prepare a mixed solution, and 23.63 g (0.1 mol) of 3-glycidoxypropyltrimethoxysilane and 127.94 g (0.9 mol) of glycidyl methacrylate were slowly added dropwise to the prepared mixed solution to prepare a reaction solution.

[0095] Transfer the above reaction solution to a dry flask equipped with a condenser and a stirrer, and conduct nitrogen replacement. While stirring the reaction solution in the reactor, raise the internal temperature to 100 °C, then carry out the polymerization reaction for 6 hours. Subsequently, lower the temperature to 50 °C and continue stirring for 3 days. After that, cool the reactor to room temperature. Subsequently, remove tetrahydrofuran using a vacuum decompression device, thereby obtaining a linear polymer (weight average molecular weight: 20,000; in Chemical Formulas 3 and 4, a:b = 1:9) including repeating units having trimethoxy functional groups (compatible functional groups) and repeating units having methacrylate functional groups (reactive functional groups).

[0096] [Synthesis Example 2D: Synthesis of Linear Polymer 2D]

[0097] Mix 100 g of tetrahydrofuran and 10 g of IRGACURE 290 (BASF) to prepare a mixed solution, and then add dropwise 142.15 g (1 mol) of glycidyl methacrylate to the prepared mixed solution to prepare a reaction solution.

[0098] Transfer the above reaction solution to a dry flask equipped with a condenser and a stirrer, and conduct nitrogen replacement. While stirring the reaction solution in the reactor, raise the internal temperature to 100 °C, then carry out the polymerization reaction for 6 hours. Subsequently, lower the temperature to 50 °C and continue stirring for 3 days. After that, cool the reactor to room temperature. Subsequently, remove tetrahydrofuran using a vacuum decompression device, thereby obtaining a linear polymer (weight average molecular weight: 20,000; in Chemical Formula 3, a = 0) including repeating units having methacrylate functional groups (reactive functional groups).

[0099] [Synthesis Example 2E: Synthesis of Linear Polymer 2E]

[0100] Mix 150 g of toluene, 150 g of acetonitrile and 15 g of 2,2 - azobis(2,4 - dimethylvaleronitrile) to prepare a mixed solution, and then add dropwise 246.41 g (0.992 mol) of 3 - methacryloxypropyltrimethoxysilane and 1.14 g (0.008 mol) of glycidyl methacrylate to the prepared mixed solution to prepare a reaction solution.

[0101] Transfer the above reaction solution to a dry flask equipped with a condenser and a stirrer, and introduce nitrogen for nitrogen replacement. While stirring the reaction solution in the reactor, raise the internal temperature to 70 °C, then carry out the polymerization reaction for 12 hours.

[0102] The linear polymer and solvent mixture obtained from the above reaction were precipitated in a 1:1 mixed solution of water and ethanol, washed with the same mixed solution, and dried at 80 °C for 12 hours, thereby obtaining a linear polymer (weight-average molecular weight: 30,000; a:b = 120:1 in Chemical Formulas 3 and 4) containing repeating units with trimethoxy functional groups (compatible functional groups) and repeating units with glycidyl functional groups (reactive functional groups).

[0103] [Example 1] Silsesquioxane 1A + Linear Polymer 2A (7:3)

[0104] 35 g of the silsesquioxane oligomer obtained from the above Silsesquioxane Polymer Synthesis Example 1A and 15 g of the linear polymer obtained from the above Silsesquioxane Polymer Synthesis Example 2A were dissolved in methyl isobutyl ketone at 50 wt%, and 100 g of a composition was prepared. Then, 5 parts by weight of an ionic UV initiator IRGACURE-250 and 1 part by weight of BYK-302 as a silicone-based surface additive were added to 100 parts by weight of the prepared composition, and the mixture was stirred for 10 minutes to prepare a photocurable resin composition.

[0105] The prepared photocurable resin composition was coated on an 80-μm transparent polyimide film from Kolon Co., and the solvent was evaporated in a drying oven at 85 °C. Subsequently, UV was irradiated using a UV device at 1 J / cm 2 to obtain the final product.

[0106] [Example 2] Silsesquioxane 1A + Linear Polymer 2A (9:1)

[0107] 45 g of the silsesquioxane oligomer obtained from the above Silsesquioxane Polymer Synthesis Example 1A and 5 g of the linear polymer obtained from the above Linear Polymer Synthesis Example 2A were dissolved in methyl isobutyl ketone at 50 wt%, and 100 g of a composition was prepared. Then, 5 parts by weight of an ionic UV initiator IRGACURE-250 and 1 part by weight of BYK-302 as a silicone-based surface additive were added to 100 parts by weight of the prepared composition, and the mixture was stirred for 10 minutes to prepare a photocurable resin composition.

[0108] The prepared photocurable resin composition was coated on an 80-μm transparent polyimide film from Kolon Co., and the solvent was evaporated in a drying oven at 85 °C. Subsequently, UV was irradiated using a UV device at 1 J / cm 2 to obtain the final product.

[0109] [Example 3] Silsesquioxane 1A + Linear Polymer 2B (9:1)

[0110] 45 g of the silsesquioxane oligomer obtained in the above silsesquioxane polymer synthesis example 1A and 5 g of the linear polymer obtained in the above linear polymer synthesis example 2B were dissolved in methyl isobutyl ketone at 50 wt%, and 100 g of a composition was prepared. Then, 5 parts by weight of an ionic UV initiator IRGACURE-250 and 1 part by weight of BYK-302 as a silicone-based surface additive were added to 100 parts by weight of the prepared composition, and stirred for 10 minutes to prepare a photocurable resin composition.

[0111] The prepared photocurable resin composition was coated on an 80-μm transparent polyimide film from Kolon Industries, and the solvent was evaporated in a drying oven at 85°C. Subsequently, UV was irradiated using a UV device at 1 J / cm 2 to obtain the final product.

[0112] [Example 4] Silsesquioxane 1B + Linear Polymer 2C (7:3)

[0113] 35 g of the silsesquioxane oligomer obtained in the above silsesquioxane polymer synthesis example 1B and 15 g of the linear polymer obtained in the above linear polymer synthesis example 2C were dissolved in methyl isobutyl ketone at 50 wt%, and 100 g of a composition was prepared. Then, 5 parts by weight of 2,4,6-trimethylbenzoyldiphenyl-phosphineoxide as a radical-type UV initiator and 1 part by weight of BYK-359 as an acrylic additive were added to 100 parts by weight of the prepared composition, and stirred for 10 minutes to prepare a photocurable resin composition.

[0114] The prepared photocurable resin composition was coated on an 80-μm transparent polyimide film from Kolon Industries, and the solvent was evaporated in a drying oven at 85°C. Subsequently, UV was irradiated using a UV device at 1 J / cm 2 to obtain the final product.

[0115] [Example 5] Silsesquioxane 1B + Linear Polymer 2C (9:1)

[0116] 45 g of the silsesquioxane oligomer obtained in the above silsesquioxane polymer synthesis example 1B and 5 g of the linear polymer obtained in the above linear polymer synthesis example 2C were dissolved in methyl isobutyl ketone at 50 wt%, and 100 g of a composition was prepared. Then, 5 parts by weight of 2,4,6-trimethylbenzoyldiphenyl-phosphineoxide as a radical-type UV initiator and 1 part by weight of BYK-359 as an acrylic additive were added to 100 parts by weight of the prepared composition, and stirred for 10 minutes to prepare a photocurable resin composition.

[0117] The prepared photocurable resin composition was coated on an 80-μm transparent polyimide film from Kolon Corporation, and the solvent was evaporated in a drying oven at 85°C. Subsequently, UV was irradiated using a UV device at 1 J / cm 2 to obtain the final product.

[0118] [Example 6] Silsesquioxane 1B + Linear Polymer 2D (9:1)

[0119] 45 g of the silsesquioxane oligomer obtained from the above silsesquioxane polymer synthesis example 1B and 5 g of the linear polymer obtained from the above linear polymer synthesis example 2D were dissolved in methyl isobutyl ketone at 50 wt% to prepare 100 g of a composition. Then, 5 parts by weight of 2,4,6-trimethylbenzoyl diphenylphosphine oxide as a radical-type UV initiator and 1 part by weight of BYK-359 as an acrylic additive were added to 100 parts by weight of the prepared composition, and stirred for 10 minutes to prepare a photocurable resin composition.

[0120] The prepared photocurable resin composition was coated on an 80-μm transparent polyimide film from Kolon Corporation, and the solvent was evaporated in a drying oven at 85°C. Subsequently, UV was irradiated using a UV device at 1 J / cm 2 to obtain the final product.

[0121] [Example 7] Silsesquioxane 1A + Linear Polymer 2A (5:5)

[0122] 25 g of the silsesquioxane oligomer obtained from the above silsesquioxane polymer synthesis example 1A and 25 g of the linear polymer obtained from the above linear polymer synthesis example 2A were dissolved in methyl isobutyl ketone at 50 wt% to prepare 100 g of a composition. Then, 5 parts by weight of the ionic UV initiator IRGACURE-250 and 1 part by weight of BYK-302 as a silicone-based surface additive were added to 100 parts by weight of the prepared composition, and stirred for 10 minutes to prepare a photocurable resin composition.

[0123] The prepared photocurable resin composition was coated on an 80-μm transparent polyimide film from Kolon Corporation, and the solvent was evaporated in a drying oven at 85°C. Subsequently, UV was irradiated using a UV device at 1 J / cm 2 to obtain the final product.

[0124] [Example 8] Silsesquioxane 1C + Linear Polymer 2A (9:1)

[0125] Dissolve 45 g of the silsesquioxane oligomer obtained from the above silsesquioxane polymer synthesis example 1C and 5 g of the linear polymer obtained from the above linear polymer synthesis example 2A in methyl isobutyl ketone at 50 wt%, and prepare 100 g of a composition. Then, add 5 parts by weight of an ionic UV initiator IRGACURE-250 and 1 part by weight of BYK-302 as a silicone-based surface additive to 100 parts by weight of the prepared composition, and stir for 10 minutes to prepare a photocurable resin composition.

[0126] Coat the prepared photocurable resin composition on an 80-μm transparent polyimide film from Kolon Corporation, and evaporate the solvent in a drying oven at 85°C. Subsequently, irradiate with UV using a UV device at 1 J / cm 2 to obtain the final product.

[0127] [Example 9] Silsesquioxane 1D + Linear Polymer 2A (9:1)

[0128] Dissolve 45 g of the silsesquioxane oligomer obtained from the above silsesquioxane polymer synthesis example 1C and 5 g of the linear polymer obtained from the above linear polymer synthesis example 2A in methyl isobutyl ketone at 50 wt%, and prepare 100 g of a composition. Then, add 5 parts by weight of an ionic UV initiator IRGACURE-250 and 1 part by weight of BYK-302 as a silicone-based surface additive to 100 parts by weight of the prepared composition, and stir for 10 minutes to prepare a photocurable resin composition.

[0129] Coat the prepared photocurable resin composition on an 80-μm transparent polyimide film from Kolon Corporation, and evaporate the solvent in a drying oven at 85°C. Subsequently, irradiate with UV using a UV device at 1 J / cm 2 to obtain the final product.

[0130] [Comparative Example 1] Use of Silsesquioxane 1A Alone

[0131] Dissolve 50 g of the silsesquioxane oligomer obtained from the above silsesquioxane polymer synthesis example 1A in methyl isobutyl ketone at 50 wt%, and prepare 100 g of a composition. Then, add 5 parts by weight of an ionic UV initiator IRGACURE-250 and 1 part by weight of BYK-302 as a silicone-based surface additive to 100 parts by weight of the prepared composition, and stir for 10 minutes to prepare a photocurable resin composition.

[0132] Coat the prepared photocurable resin composition on an 80-μm transparent polyimide film from Kolon Corporation, and evaporate the solvent in a drying oven at 85°C. Subsequently, irradiate with UV using a UV device at 1 J / cm 2 to obtain the final product.

[0133] [Comparative Example 2] Silsesquioxane 1A + Nonlinear Polymer (Pentaerythritol Glycidyl Ether)

[0134] 45 g of the silsesquioxane oligomer obtained from the above silsesquioxane polymer synthesis example 1A and 5 g of pentaerythritol glycidyl ether were dissolved in methyl isobutyl ketone at 50% by weight to prepare 100 g of a composition. Then, 5 parts by weight of an ionic UV initiator IRGACURE-250 and 1 part by weight of BYK-302 as a silicone-based surface additive were added to 100 parts by weight of the prepared composition, and stirred for 10 minutes to prepare a photocurable resin composition.

[0135] The prepared photocurable resin composition was coated on an 80-μm transparent polyimide film from Kolon Corporation, and the solvent was evaporated in a drying oven at 85°C. Subsequently, UV was irradiated using a UV device at 1 J / cm 2 to obtain the final product.

[0136] [Comparative Example 3] Silsesquioxane 1A + PMMA Resin (9:1)

[0137] 45 g of the silsesquioxane oligomer obtained from the above silsesquioxane polymer synthesis example 1A and 5 g of IH830 (PMMA resin) from LG Corporation were dissolved in toluene at 50% by weight to prepare 100 g of a composition. Then, 5 parts by weight of an ionic UV initiator IRGACURE-250 and 1 part by weight of BYK-302 as a silicone-based surface additive were added to 100 parts by weight of the prepared composition, and stirred for 10 minutes to prepare a photocurable resin composition.

[0138] The prepared photocurable resin composition was coated on an 80-μm transparent polyimide film from Kolon Corporation, and the solvent was evaporated in a drying oven at 85°C. Subsequently, UV was irradiated using a UV device at 1 J / cm 2 to obtain the final product.

[0139] [Comparative Example 4] Caged Silsesquioxane + Linear Polymer 2A (9:1)

[0140] Dissolve 45 g of EP0409 from Hybrid Plastics (cage-structured silsesquioxane oligomer with only epoxy-reactive functional groups and no compatibility functional groups) and 5 g of the linear polymer obtained from the above linear polymer synthesis example 2A in methyl isobutyl ketone at 50 wt%, and prepare 100 g of a composition. Then, add 5 parts by weight of an ionic UV initiator IRGACURE-250 and 1 part by weight of BYK-302 as a silicone-based surface additive to 100 parts by weight of the prepared composition, and stir for 10 minutes to prepare a photocurable resin composition.

[0141] Coat the prepared photocurable resin composition on an 80-μm transparent polyimide film from Kolon Co., and evaporate the solvent in a drying oven at 85 °C. Subsequently, irradiate with UV using a UV device at 1 J / cm 2 to obtain the final product.

[0142] [Comparative Example 5] Cage-structured silsesquioxane + Linear polymer 2D (9:1)

[0143] Dissolve 45 g of MA0735 from Hybrid Plastics (cage-structured silsesquioxane oligomer with only epoxy-reactive functional groups and no compatibility functional groups) and 5 g of the linear polymer obtained from the above linear polymer synthesis example 2D in methyl isobutyl ketone at 50 wt%, and prepare 100 g of a composition. Then, add 5 parts by weight of 2,4,6-trimethylbenzoyl diphenylphosphine oxide as a radical-type UV initiator and 1 part by weight of BYK-359 as an acrylic additive to 100 parts by weight of the prepared composition, and stir for 10 minutes to prepare a photocurable resin composition.

[0144] Coat the prepared photocurable resin composition on an 80-μm transparent polyimide film from Kolon Co., and evaporate the solvent in a drying oven at 85 °C. Subsequently, irradiate with UV using a UV device at 1 J / cm 2 to obtain the final product.

[0145] [Experimental Example]

[0146] For the final products obtained from the above Examples 1 to 9 and Comparative Examples 1 to 5, measure the adhesion, pencil hardness, transmittance, haze, bending properties, and cracking strain respectively. The results are shown in Table 1 below.

[0147] - Adhesion evaluation:

[0148] According to JIS K5600-5-6 standard, use a cutting knife to cut into a grid pattern at 1 mm intervals to form 100 small grids. After sticking on the tape, tear it off in the 90° direction, and visually confirm whether the coating adheres to the tape and peels off from the substrate. Mark with the number of non-peeled ones out of 100 (e.g., mark as "number of non-peeled ones / 100", if all 100 are peeled off, mark as 100 / 100).

[0149] - Pencil hardness:

[0150] Evaluate according to JIS K5600-5-4 standard under a load of 750 g. The pencils used are Mitsubishi products. Each pencil hardness grade is tested 5 times. If there are more than 2 scratches, it is judged as defective. Mark in the form of "measured hardness / number of times without scratches / test times".

[0151] - Transmittance and haze:

[0152] Measure according to ISO 14782 standard using the COH-400 equipment of Nippon Denshoku Industries Co., Ltd. Each sample is measured 5 times and the average value is taken.

[0153] - Bending performance evaluation:

[0154] Use a bending tester manufactured by Cobotech (South Korea) to repeatedly bend the sample with a 1R value. Observe whether there are cracks every 1000 times within 10,000 times, and every 50,000 times above 10,000 times. If the sample is damaged or cracked, stop the measurement and record the measurement times.

[0155] - Cracking strain:

[0156] Install the prepared film in the universal testing machine of Instron Corporation, stretch it at a speed of 1 mm / min, measure the length of elongation when cracks occur, convert it into a percentage and record it.

[0157] Table 1

[0158]

[0159]

[0160] As can be seen from Table 1 above, compared with the case of using silsesquioxane alone (Comparative Example 1), as shown in the examples of the present invention, when used in combination with a linear polymer, the bending properties and cracking strain are improved. In addition, from Example 1 (ratio 7:3) and Example 2 (ratio 9:1), it can be confirmed that the higher the proportion of the linear polymer in the silsesquioxane polymer and the linear polymer, the more excellent the bending properties and cracking strain. However, as shown in Example 7 (ratio 5:5), when the proportion of the linear polymer is too high, physical properties such as hardness, transmittance, and haze may decrease. In addition, there is a difference between Example 1 and Example 3 in whether the linear polymer used has a compatible functional group. When using a linear polymer with a compatible functional group under the same conditions, the bending properties and cracking strain are further improved.

[0161] In addition, as can be seen from Comparative Examples 1 to 5, even when other polymers are mixed with silsesquioxane, in the case of mixing a non-linear polymer (Comparative Example 2), or in the case of mixing polymethyl methacrylate that does not have reactive functional groups and compatible functional groups at the same time (Comparative Example 3), or in the case of using a cage-structured silsesquioxane (Comparative Examples 4 and 5), it will instead cause a serious decline in all physical properties compared with the case of using silsesquioxane alone (Comparative Example 1).

[0162] Although the above has been described with reference to the preferred embodiments of the present invention, those skilled in the art can understand that the present invention can be variously modified and changed without departing from the spirit and scope of the present invention described in the appended claims.

Claims

1. A coating composition, characterized in that, Comprising: A silsesquioxane polymer comprising repeating units of the following Chemical Formula 1 and repeating units of the following Chemical Formula 2; and A linear polymer comprising a first reactive functional group that is reactive with the above silsesquioxane polymer, [Chemical Formula 1] [Chemical Formula 2] In the above Chemical Formula 1 and Chemical Formula 2, R1 is *-L1-R a , R2 is *-L2-R b , L1 and L2 each independently represent a direct bond, an alkylene group having 1 to 10 carbon atoms, an oxyalkylene group having 1 to 10 carbon atoms, or an alkyl ester group having 1 to 10 carbon atoms, Each L1, each L2, or L1 and L2 are the same or different, R a and R b each independently represents a second reactive functional group, Each R a 、each R b or R a and R b are the same or different, R3 is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, n and m are each independently an integer from 1 to 100,000.

2. The coating composition according to claim 1, characterized in that n / m is from 1 to 50.

3. The coating composition according to claim 1, characterized in that The above second reactive functional group is an amino group, an acryloyl group, a methacryloyl group, a vinyl group, an epoxy group, or a thiol group.

4. The coating composition according to claim 1, characterized in that The above L1 and L2 each independently are selected from the group consisting of a direct bond, an alkylene group having 1 to 6 carbon atoms, and an oxyalkylene group having 1 to 10 carbon atoms.

5. The coating composition according to claim 1, characterized in that The above first reactive functional group is an amino group, an acryloyl group, a methacryloyl group, a vinyl group, an epoxy group, or a thiol group.

6. The coating composition according to claim 1, characterized in that The above first reactive functional group is an acryloyl group, a methacryloyl group, or an epoxy group.

7. The coating composition according to claim 1, characterized in that The above linear polymer further comprises a compatibility functional group.

8. The coating composition according to claim 7, characterized in that The above compatibility functional group is a hydroxyl group or an alkoxy group having 1 to 20 carbon atoms.

9. The coating composition according to claim 1, characterized in that The above linear polymer comprises repeating units represented by the following Chemical Formula 3 and repeating units represented by the following Chemical Formula 4: [Chemical Formula 3] [Chemical Formula 4] In the above Chemical Formula 3 and Chemical Formula 4, L3 and L4 each independently are selected from the group consisting of a direct bond, an alkylene group having 1 to 10 carbon atoms, an ether, an ester, an oxyalkylene group having 1 to 10 carbon atoms, and an alkyl ester group having 1 to 10 carbon atoms, R4 is a compatibility functional group providing compatibility with the above silsesquioxane polymer, R6 is a first reactive functional group reactive with the above silsesquioxane polymer, R5 and R7 each independently are selected from the group consisting of hydrogen, deuterium, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, and a first reactive functional group reactive with the above silsesquioxane polymer, a is 0 or an integer from 1 to 100,000, b is an integer from 1 to 100,000, and a / b is from 0 to 100.

10. The coating composition according to claim 9, characterized in that The above-mentioned R4 and the above-mentioned R1 in Chemical Formula 1 have similar polarities.

11. The coating composition according to claim 9, wherein The above R4 is *-L5-R8 or *-L6-SiR9R 10 R 11 , wherein, the above-mentioned L5 and L6 are each independently a direct bond, an alkylene group having 1 to 10 carbon atoms, an oxyalkylene group having 1 to 10 carbon atoms, or an alkyl ester having 1 to 10 carbon atoms, R8, R9, and R 10 and R 11 are each independently a hydroxyl group or an alkoxy group having 1 to 10 carbon atoms.

12. The coating composition according to claim 9, wherein the above-mentioned first reactive functional group is an amino group, an acryloyl group, a methacryloyl group, a vinyl group, an epoxy group, or a thiol group.

13. The coating composition according to claim 9, wherein the above-mentioned R5 and R7 are each independently hydrogen or an alkyl group having 1 to 10 carbon atoms.

14. The coating composition according to claim 8, characterized in that The above-mentioned a is an integer from 1 to 100,000, and the above-mentioned a / b is from 1 / 100 to 100.

15. The coating composition according to claim 1, wherein the weight ratio of the above-mentioned silsesquioxane polymer to the above-mentioned linear polymer is from 10:1 to 1:

10.

16. A coating film, wherein it is formed from the silsesquioxane polymer according to claim 1 and the linear polymer according to claim 1.

17. The coating film according to claim 16, wherein the cracking strain value is 4.0% or more.

18. The coating film according to claim 16, wherein it is used for a flexible display.

19. A display panel, characterized in that, Comprising: a substrate; the coating film according to claim 16, formed on one surface of the above-mentioned substrate; and a light-emitting element, formed on the other surface of the above-mentioned substrate.

20. The display panel according to claim 19, wherein the above-mentioned substrate is polyimide, polyethylene terephthalate, polyethylene naphthalate, polycarbonate, or ultra-thin tempered glass.

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