KR20160081848A - Composition For Hard Coating and Hard Coating Film Including Cured Product Of The Same As The Coating Layer - Google Patents

Abstract

The present invention relates to a resin composition for hard coating and a hard coating film including a cured product thereof as a coating layer. The resin composition includes a siloxane resin formed by siloxane resin chemical bonds chemically bonded by compounds which include an alkoxy silane having an alicyclic epoxy group and alkoxy metal compounds, wherein the content of the alkoxy metal compounds is 0.2-5.0 mol% with respect to the total mole of the alkoxy silane and the alkoxy metal compounds.

Description

[0001] The present invention relates to a hard coating film comprising a resin composition for hard coating and a cured product thereof as a coating layer (Composition For Hard Coating and Hard Coating Film Including Cured Product of The Same As The Coating Layer)

The present invention relates to a resin composition for hard coating and a hard coating film comprising the same as a coating layer, and more particularly, to a resin composition for hard coating which exhibits excellent hardness without curling and a cured product thereof as a coating layer ≪ / RTI >

Transparent polymer films are widely used as core materials in the optical and transparent display industries, and are being replaced by glass in the display industry due to their light weight and ease of processing. However, it has low surface hardness compared with glass and has a disadvantage of abrasion resistance. For this purpose, high hardness coating, that is, hard coating technology, has been an important issue for improving the surface hardness of the polymer film.

The materials used for the hard coating are largely divided into organic, inorganic, and inorganic composite materials. Organic materials have the advantages of flexibility and moldability due to the characteristics of organic materials, but they have a disadvantage of low surface hardness. It has the advantages of hardness and transparency, but has the disadvantage of poor flexibility and moldability. As a result, organic and inorganic composite materials having both the merits of both materials are now in the spotlight and many studies have been carried out. However, the merits of both materials are insufficient yet.

On the other hand, there is a light or thermosetting coating agent as one of commonly used coating agents for hard coating. The photocurable coating agent can be cured in a short time and can be cured at room temperature, and is used as a surface protective coating for various plastic products. In order for such a coating to be usefully used for optical purposes, it should have good adhesion with a film along with hardness, and should not have a curl phenomenon or a rainbow phenomenon. In particular, the curl phenomenon can be a serious disadvantage in the roll-to-roll process, which is a mass production process, and is a particularly demanded property because it may cause problems in future durability even when it is provided as a product.

As a prior art related to optical or thermosetting coatings applied to optical products, Korean Patent Laid-Open Publication No. 2010-0041992 discloses a hard hard coating film composition comprising an ultraviolet curable polyurethane acrylate oligomer. The patent minimizes the curling phenomenon and prevents rainbow phenomenon due to optical interference, but has a low surface hardness limit as a hard coating film.

Korean Patent Laid-Open Publication No. 2011-001391 proposes a vinyl oligosiloxane hybrid composition containing a metal catalyst. The above-mentioned prior art has been reported to have a low shrinkage percentage due to a high proportion of an inorganic material as a composition of an inorganic network structure, and to have excellent optical properties and heat resistance. However, due to the high mineral content, the impact resistance can be disadvantageous and there is a limit of flexibility.

In addition, International Publication No. WO2013-187699 proposes a high hardness siloxane resin composition containing an alicyclic epoxy group, a process for producing the same, and an optical film comprising the cured product. Although the prior art has achieved a high hardness of 9 H, there is still a problem that the weatherability due to the use of a single monomer and the use of a cationic initiator may be a problem and curling may occur.

As described above, when the advantages of organic materials are emphasized, they have weaknesses in hardness and permeability, and when they emphasize advantages of inorganic materials, they have weaknesses such as flexibility. In addition, if the surface hardness of the hard coat layer is improved by forming a dense network between the organic materials, the shrinkage increases and curl and cracks are generated. As a result, adhesiveness is reduced and the coating layer may be detached. Therefore, the development of a high hardness coating material having no curl and ease of processing is also necessary for wider use of polymer films.

Accordingly, it is an object of the present invention to provide a resin composition for hard coating which is chemically bonded with an organic-inorganic composite and a metal element to secure a space in a molecular structure to suppress shrinkage while maintaining surface hardness and to prevent curling.

Further, it is an object of the present invention to provide a hard coating film which is coated with the above resin composition and has no curling and has a high surface hardness.

In order to solve the above problems, a first preferred embodiment of the present invention includes a siloxane resin chemically bonded by compounds comprising an alkoxysilane represented by Chemical Formula 1 and an alkoxy metal compound represented by Chemical Formula 2, Wherein the alkoxy metal compound is contained in an amount of 0.2 mol% to 5.0 mol% based on the total moles of the alkoxysilane and the alkoxy metal compound.

???????? R ¹ _n Si (OR ² ) _{4 -n} ????? (1)

M (OR < ³ &gt;) m

In the general formulas (1) and (2), R ¹ is a C ₁ to C ₃ alkyl group containing an alicyclic epoxy group, R ² is a linear or branched C ₁ to C ₄ alkyl group, and R ³ is a linear or branched C ₁ to C ₄ alkyl group. M is one or more metal elements selected from the group consisting of aluminum, titanium and zinc, n is an integer of 1 to 3, and m is an integer of 2 to 4.

In addition, a second preferred embodiment of the present invention relates to a substrate film; And a hard coating layer laminated on at least one surface of the base film and formed by curing the resin composition for hard coating of the first embodiment.

According to the present invention, it is possible to provide a resin composition for hard coating which is excellent in surface hardness while suppressing shrinkage and free from curling, and it is also possible to provide a hard coating film containing a coating layer free of curling and having high surface hardness Can be provided.

In particular, the resin composition for hard coating according to the present invention has an intermolecular space because the metal is chemically bonded to the molecule based on alicyclic epoxy, thereby minimizing shrinkage upon curing and securing excellent surface hardness, Can be effectively suppressed.

FIG. 1 is a reaction formula showing the synthesis mechanism of the siloxane resin contained in the resin composition for hard coating according to the sol-gel method of the present invention.

The present invention provides a resin composition for hard coating comprising a siloxane resin chemically bonded by alkoxy silane containing compounds having an alicyclic epoxy group and compounds containing an alkoxy metal compound.

In the present invention, the alkoxysilane may be represented by the following general formula (1). According to a more preferred embodiment of the present invention, the alkoxysilane represented by the following general formula (1) is a 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane , 2- (3,4-epoxycyclohexyl) ethyl triethoxysilane and 2- (3,4-epoxycyclohexyl) ethyltripropoxysilane.

???????? R ¹ _n Si (OR ² ) _{4 -n} ????? (1)

Wherein R ¹ is a linear C ₁ to C ₃ alkyl group containing an alicyclic epoxy group, R ² is a linear or branched C ₁ to C ₄ alkyl group, and n is an integer of 1 to 3.

More specifically, the alicyclic epoxy group contained in R ¹ of Formula 1 preferably has an alicyclic structure formed by C ₃ to C ₈ alicyclic alkyl groups. However, the C ₃ to C ₅ When cycloaliphatic be of may curling phenomenon caused by reducing intermolecular spacing, C ₇ to in the epoxy curing reaction can take place later, if the cycloaliphatic be of, improve the curing speed and the local characteristic aspects of the C ₈ C ₆ It is preferably an alicyclic epoxy group, but the present invention is not necessarily limited thereto.

In the present invention, the epoxy-based monomer represented by the above formula (1) has a low curing shrinkage ratio, which is very significant from the standpoint of suppressing curling and ensuring excellent surface hardness. If the formula (1) is an acrylic monomer, it can exhibit a fast curing rate and a high hardness, but the contraction ratio is high and the curling probability can be increased. When the monomer of formula (1) is an isocyanate-based monomer, the flexibility is high due to its high modulus of elasticity, and thus the curling probability is low, but it can exhibit low surface hardness.

On the other hand, according to the present invention, the compound of formula (1) is an epoxy-based monomer, which has a high surface hardness relative to an isocyanate group and a curing shrinkage ratio lower than that of an acrylic group. In particular, since the compound of formula (1) of the present invention is an alicyclic epoxy-based monomer, securing the intermolecular space when cured is more advantageous than the linear epoxy-based monomer, the resin composition for hard coating of the present invention suppresses hardening shrinkage, .

However, since curling due to curing shrinkage is an inevitable phenomenon, the present invention provides a siloxane resin chemically bonded with a compound containing both an alkoxy silane and an alkoxy metal compound represented by the following formula (2) . That is, since the structure in which the alkoxysilane and the alkoxy metal compound are combined in the molecular structure is included, the intermolecular space can be further secured by the metal element, so that the hard coating resin composition of the present invention minimizes the hardening shrinkage, It can be dramatically reduced.

M (OR < ³ &gt;) m

In the general formula (2), R ³ is a linear or branched C ₁ to C ₄ alkyl group, M is at least one metal element selected from the group consisting of aluminum, titanium and zinc, and m is an integer of 2 to 4.

In the present invention, the alkoxy metal compound is contained in an amount of 0.2 mol% to 5.0 mol% based on the total molar amount of the alkoxysilane and the alkoxy metal compound, which is preferable in terms of ease of processing and curl generation effectively . When the alkoxy metal compound is contained in an amount of less than 0.2 mol%, the curling inhibition effect may be insignificant. When the reaction temperature is lowered or the polymerization is stopped within a short time, addition of up to 5.0 mol% of the metal compound is possible. However, when it is contained in an amount exceeding 5.0 mol%, the gelation rapidly proceeds, and the viscosity of the resin is likely to rise at a high rate, and the processability may be significantly lowered due to the strong solvent resistance, May not be large. It is more preferable that the alkoxy metal compound is contained in an amount of 0.2 mol% to 3.0 mol%.

Hereinafter, the chemical reaction between the alkoxysilane and the alkoxy metal compound of the present invention will be described in more detail with reference to FIG.

FIG. 1 is a schematic representation of the reaction mechanism by the Sol-Gel method during the chemical reaction between the alkoxysilane and the metal compound. The entire siloxane resin can be formed by repeating the Route 1 or Route 2 reaction.

In the present invention, the siloxane resin forming reaction may proceed at room temperature, but may be stirred at 50 ° C to 120 ° C for 1 hour to 120 hours to promote the reaction. As a catalyst for carrying out the hydrolysis and condensation reaction during the reaction, an acid catalyst such as hydrochloric acid, acetic acid, hydrogen fluoride, nitric acid, and sulfuric acid iodic acid, a base such as ammonia, potassium hydroxide, sodium hydroxide, barium hydroxide, imidazole A catalyst, and an amberite may be used. These catalysts may be used alone or in combination. The amount of the catalyst is not particularly limited, but 0.0001 to about 10 parts by weight based on 100 parts by weight of the siloxane resin may be added.

When the hydrolysis and condensation reaction proceeds, alcohol as a by-product is produced. By eliminating it, the reverse reaction can be reduced and the reaction can proceed more quickly, and the reaction rate can be controlled through the reaction. After completion of the reaction, the by-product can be removed by decompression and heating.

The siloxane resin synthesized by the condensation reaction can control the viscosity and the curing rate by the monomers added during the reaction, thereby providing an optimal resin composition suitable for the application. In addition, the siloxane resin obtained through the above-mentioned reaction can prevent the curling due to curing shrinkage because intermolecular space is secured during crosslinking, and it is possible to realize high surface hardness by crosslinking and metal elements.

According to a preferred embodiment of the present invention, the resin composition for hard coating may further include an initiator for the polymerization of the siloxane resin. For example, a photopolymerization initiator such as an organic metal salt and a thermal polymerization initiator such as an amine or imidazole Can be used. In this case, the amount of the initiator to be added is not particularly limited, but about 0.01 to 10 parts by weight may be added to about 100 parts by weight of the siloxane resin.

In addition, the resin composition for hard coating of the present invention may further include an organic solvent for controlling the viscosity of the siloxane resin to facilitate workability and adjusting the thickness of the coating film. The amount of the organic solvent to be added is not particularly limited and examples of usable organic solvents include ketones such as acetone, methyl ethyl ketone, methyl butyl ketone and cyclohexanone, cellosolves such as methyl cellosolve and butyl cellosolve, Or alcohols such as ethers such as ethyl ether and dioxane, isobutyl alcohol, isopropyl alcohol, butanol and methanol, halogenated hydrocarbons such as dichloromethane, chloroform and trichlorethylene, and halogenated hydrocarbons such as n-hexane, And solvents composed of hydrocarbons and the like.

In one embodiment of the present invention, the siloxane resin may further include an antioxidant to suppress the oxidation reaction resulting from the polymerization reaction. The siloxane resin may further include a leveling agent or a coating aid, no.

The siloxane resin of the present invention may have a weight average molecular weight of 5,000 to 22,000 and a polydispersity index (PDI) of 1.5 to 3.1. In the present invention, the molecular weight and molecular weight distribution (PDI, Mw / Mn) were determined by polystyrene conversion weight average molecular weight (Mw) and number average molecular weight (Mn) by gel permeation chromatography (GPC) . More specifically, 20 μl of the solution was dissolved in tetrahydrofuran so as to have a concentration of 1% of the polymer to be measured, and the solution was introduced at a flow rate of 1.0 mL / min and analyzed at 30 ° C. In addition, two columns of Waters Styragel HR3 were connected in series, and the detector was measured at 40 占 폚 using an RI detector (Waters, 2414). Further, the measured weight average molecular weight was divided by the number average molecular weight to calculate PDI (molecular weight distribution diagram).

The present invention relates to a base film; And a hard coating layer formed on at least one side of the base film and formed by curing the resin composition for hard coating. The hard coating film of the present invention may have a surface hardness of 5H to 9H according to the ASTM D3363 measurement standard in the direction in which the coating layer is formed.

In the present invention, it is possible to further perform a process of making the surface uniform by a separate heat treatment before photopolymerization or thermal polymerization curing. Such additional heat treatment can further improve the hardness of the hard coating layer. In this case, in the case of photopolymerization, the heat treatment may be performed at a temperature of 40 ° C or more and about 200 ° C or less for 2 minutes to 60 minutes depending on the substrate, and in the case of thermal polymerization, But it is not limited thereto. Further, since the photo-polymerization heat treatment is 50mJ / cm ² or more 20,000mJ / cm ² or less, more preferably 200mJ / cm ² more than 5,000mJ / cm ² It may be advantageous in terms of ensuring sufficient hardness and further suppressing yellowing.

Examples of the method of applying the hard coating resin composition to a substrate include spraying, dip coating, spin coating, die coating, comma coating, screen coating, inkjet printing, pad printing, knife coating, kiss coating, bar coating and gravure coating The thickness of the hard coating layer formed of the hard coating resin composition can be easily controlled according to the kind of the base material and the application. In the present invention, it is 2 to 60 탆, preferably 10 to 30 탆 It is possible to secure both the hardness and the bendability of the hard coating film at a thickness of 占 퐉.

Although not limited thereto, in the present invention, the base film may be a polyethylene sulfonate (PES) film, a polyethylene terephthalate (PET) film, a polycarbonate (PC) film, a polymethylmethacrylate (PMMA) film, , Manufactured by BF Goodrich Co., USA) and a polyimide (PI) film may be laminated alone or in combination of two or more thereof.

In addition, the resin composition for hard coating of the present invention may be applied to inorganic substrates such as glass, quartz, glass wafers, and silicon wafers to form hard coating layers, depending on the purpose.

Example

Hereinafter, the present invention will be described in more detail with reference to Examples. These examples are for the purpose of illustrating the present invention more specifically, and the present invention is not limited thereto.

Example  One. Photocuring  coating Cured goods  Produce

After adding 227.96 mL of KBM-303 (Shinetsu), 2.96 mL of Titanium isopropoxide (Sigma-Aldrich) and 27.02 mL of H ₂ O into a 500 mL flask, 0.2 g of sodium hydroxide was added as a catalyst, Stir for 24 hours. Thereafter, the solution was filtered using a 0.45-μm Teflon filter to obtain a titanyl-covalently bonded siloxane resin. The molecular weight of the resin was measured by using a GPC, it was confirmed to be having a number average molecular weight of 20146 and a weight average molecular weight, and 2.78 polydispersity index (PDI, M _w / M _n) value of a 7245.

Next, 3 parts by weight of IRGACURE 250 (BASF) as a photoinitiator was added to 100 parts by weight of the resin, and then coated on the surface of the colorless polyimide with different thicknesses of 10, 20 and 30 μm. And exposed to light for curing. Thus, a hard hardened coating cured product was prepared.

Example  2. Heat curing  coating Cured goods  Produce

2 parts by weight of 2-ethyl-4-methylimidazole (Sigma-Aldrich) was added as a thermal polymerization initiator instead of the photoinitiator to 100 parts by weight of the resin after the siloxane resin was obtained in the same manner as in Example 1 to obtain a colorless polyimide surface Coated at different thicknesses of 10, 20 and 30 μm. This was heat-treated at a temperature of 120 ° C for 4 hours to prepare a hard-coated cured product.

Example  3. Aluminum alkoxide  adding

1.62 g of aluminum ethoxide (Sigma-Aldrich) was added instead of 2.96 mL of titanium isopropoxide to prepare a siloxane resin having a number average molecular weight of 7027, a weight average molecular weight of 21325 and a polydispersity index of 3.03. A resin was prepared and coated to prepare a coating cured product.

Example  4th Zinc alkoxide  adding

Except that 1.27 g of Zinc methoxide (Sigma-Aldrich) was added instead of 2.96 mL of Titanium isopropoxide to prepare a siloxane resin having a number average molecular weight of 7312, a weight average molecular weight of 20072 and a polydispersity index of 2.74. A resin was prepared and coated to prepare a coating cured product.

Example  5. Titanium alkoxide  Content change 0.1 mol% )

Except that 0.30 mL of Titanium isopropoxide (Sigma-Aldrich) was added to prepare a siloxane resin having a number average molecular weight of 7592, a weight average molecular weight of 20324 and a polydispersity index of 2.67. To prepare a coating cured product.

Example  6. Titanium alkoxide  ratio change 0.5 mol% )

1.48 mL of Titanium isopropoxide (Sigma-Aldrich) was added to prepare a resin in the same manner as in Example 1, except that a siloxane resin having a number average molecular weight of 6985, a weight average molecular weight of 19952, and a polydispersity index of 2.85 was prepared. To prepare a coating cured product.

Example  7. Titanium alkoxide  ratio change 1.5 mol% )

4.44 mL of Titanium isopropoxide (Sigma-Aldrich) was added to prepare a resin in the same manner as in Example 1, except that a siloxane resin having a number average molecular weight of 7428, a weight average molecular weight of 20523, and a polydispersity index of 2.76 was prepared. To prepare a coating cured product.

Example  8. Titanium alkoxide  ratio change 1.8 mol% )

Except that 5.33 mL of titanium isopropoxide (Sigma-Aldrich) was added to prepare a siloxane resin having a number average molecular weight of 7790, a weight average molecular weight of 21338, and a polydispersity index of 2.74. To prepare a coating cured product.

Example  9. Titanium alkoxide  ratio change 2.0 mol% ) And reaction time adjustment

A siloxane resin having a number average molecular weight of 3438 and a weight average molecular weight of 5151 and a polydispersity index of 1.5 was obtained in the same manner as in Example 1 except that 5.92 mL of titanium isopropoxide (Sigma-Aldrich) was added and the reaction time was changed to 5 hours , And coated to prepare a coated cured product.

Example  10. Titanium alkoxide  ratio change 5.0 mol% ) And reaction time adjustment

A siloxane resin having a number average molecular weight of 2654 and a weight average molecular weight of 5600 and a polydispersity index of 2.1 was obtained in the same manner as in Example 1 except that 14.80 mL of titanium isopropoxide (Sigma-Aldrich) was added and the reaction time was changed to 2 hours , And coated to prepare a coated cured product.

Comparative Example  One. Photocuring  coating Cured goods

A siloxane resin having a number average molecular weight of 5395, a weight average molecular weight of 15116 and a polydispersity index of 2.80 was obtained in the same manner as in Example 1 except that titanium isopropoxide was not added. Thereafter, the coating was cured under the same conditions as in Example 1 to prepare a coated cured product coated with the siloxane resin obtained in Comparative Example 1.

Comparative Example  2. Heat curing  coating Cured goods

A coating cured product was prepared using the same resin as in Comparative Example 1, but using the same thermosetting coating method as in Example 2.

Comparative Example  3. Titanium alkoxide  ratio change 5.5 mol% ) And reaction time adjustment

A resin was prepared and coated on a film in the same manner as in Example 1 except that 16.28 mL of Titanium isopropoxide (Sigma-Aldrich) was added and the reaction time was controlled to be less than 1 hour. However, it was difficult to control the gelation of the resin Accordingly, the solubility in an organic solvent was abruptly lowered so that it was not suitable for coating.

Subsequently, the properties of the above-mentioned Examples 1 to 10 and Comparative Examples 1 and 2 were evaluated by the following methods, except for Comparative Example 3 which is not suitable for coating, and the results are shown in Table 1 below.

(1) Surface hardness: The pencil hardness was measured at a rate of 180 mm / min under a load of 750 gf according to ASTM D3363 using a pencil hardness tester manufactured by IMOTO, Japan.

(2) Curl generation: When the coated film was cut into a plane of 30 cm x 21 cm, the one side of each corner was measured as the maximum distance from the plane.

(3) Chemical resistance: A 1 cm X 1 cm film cut on a slide glass was fixed with an adhesive tape (3M) so that its coated side was facing up, and then immersed in an aqueous solution of 0.05% acetone, NMP and KOH for 12 hours. And if it does not occur, it is judged to be good and it is reflected in Table 1 below.

Alkoxy metal
content Surface hardness curl Chemical resistance 10um 20um 30um 10um 20um 30um 10um 20um 30um Example 1 1 mol% 7H 8H 9H 0cm 0cm 0.5cm Good Good Good Example 2 1 mol% 5H 6H 6H 0cm 0cm 0cm Good Good Good Example 3 1 mol% 7H 8H 8H 0cm 0cm 0.7cm Good Good Good Example 4 1 mol% 7H 8H 8H 0cm 0cm 0.6cm Good Good Good Example 5 0.1 mol% 6H 7H 7H 1cm 1.5cm 2.0cm Good Good Good Example 6 0.5 mol% 6H 7H 8H 0.7cm 1.0cm 1.8cm Good Good Good Example 7 1.5 mol% 7H 8H 9H 0cm 0cm 0.5cm Good Good Good Example 8 1.8 mol% 7H 8H 9H 0cm 0cm 0.5cm Good Good Good Example 9 2 mol% 7H 8H 9H 0cm 0cm 0.5cm Good Good Good Example 10 5 mol% 7H 8H 9H 0cm 0cm 0.8cm Good Good Good Comparative Example 1 - 5H 5H 6H 2cm 3cm 5cm Good Good Good Comparative Example 2 - 2H 3H 3H 0cm 0cm 0cm Good Good Good Comparative Example 3 5.5 mol% Decrease in coating property

According to the measurement results of the surface hardness according to the thickness, it was confirmed that the surface hardness and the curl characteristic of Examples 1 to 10 in which alkoxy metal was added were significantly improved as compared with Comparative Examples 1 and 2, The curing by photocuring (Example 1) was found to be more advantageous for surface hardness. On the other hand, it was confirmed that no curling occurs even at a thickness of 30 탆 at the time of thermal curing, and that the thermal curing can be more advantageous in terms of suppressing curling.

Further, by comparing the curl characteristics of Examples 5 to 10, it was confirmed that when the addition amount of the alkoxy metal is further increased, the intermolecular distance in the molecular structure is secured and the curl characteristic can be further improved. However, at the time when the alkoxy metal content was 2 mol% or more (Examples 9 and 10), it was possible to suppress the surface hardness and curl formation by reducing the reaction time, but in the case of Comparative Example 3 exceeding 5.0 mol% If the reaction is stopped before the gelation is proceeded, sufficient reaction can not be performed, or if the reaction time is minimized in consideration of sufficient reaction, the progress of gelation can not be suppressed and the viscosity of the resin is rapidly increased. I could confirm.

Claims (6)

A siloxane resin chemically bonded by compounds comprising an alkoxysilane represented by the following formula (1) and an alkoxy metal compound represented by the following formula (2)
Wherein the alkoxy metal compound is contained in an amount of 0.2 mol% to 5.0 mol% based on the total moles of the alkoxysilane and the alkoxy metal compound.
???????? R ¹ _n Si (OR ² ) _4-n ?????
M (OR < ³ &gt;) m
Wherein R ¹ is a linear C ₁ to C ₃ alkyl group containing an alicyclic epoxy group, R ² is a linear or branched C ₁ to C ₄ alkyl group, and R ³ is a linear or branched C ₁ to C ₄ alkyl group. M is one or more metal elements selected from the group consisting of aluminum, titanium and zinc, n is an integer of 1 to 3, and m is an integer of 2 to 4.
The resin composition for hard coating according to claim 1, wherein the siloxane resin has a weight average molecular weight of 5,000 to 22,000 and a polydispersion index (PDI) of 1.5 to 3.1.
The method of claim 1, wherein the alkoxysilane is selected from the group consisting of 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltriethoxysilane and 2- -Epoxycyclohexyl) ethyltripropoxysilane. &Lt; / RTI &gt;
The hard coating resin composition according to claim 1, wherein the resin composition for hard coating further comprises at least one additive selected from the group consisting of an organic solvent, a photoinitiator, a thermal initiator, an antioxidant, a leveling agent, Composition.
A hard coating film comprising a base film and a hard coat layer formed by curing at least one surface of the base film with the resin composition for hard coating according to any one of claims 1 to 4.
6. The hard coating film according to claim 5, wherein the hard coating film has a surface hardness in a direction in which a coating layer is formed is from 5H to 9H according to ASTM D3363 measurement standard.

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