KR102293821B1 - Composition for making hard coating layer - Google Patents

Abstract

The present invention relates to a composition for forming a hard coating layer, and more particularly, a (meth)acrylate siloxane resin having a weight average molecular weight of 500 to 30,000 and a polydispersity index (PDI) of 2.0 to 4.0; A crosslinking agent comprising a (meth)acrylate-based compound; Colloidal silica comprising a (meth)acrylate group on the surface and having an average particle diameter of 1 to 200 nm; And by including a photoinitiator, it has remarkably improved hardness and relates to a composition for forming a hard coat layer capable of forming a hard coat layer having excellent flexibility.

Description

Composition for forming a hard coating layer {COMPOSITION FOR MAKING HARD COATING LAYER}

The present invention relates to a composition for forming a hard coat layer.

Recently, a thin display device using a flat panel display such as a liquid crystal display or an organic light emitting diode display has received great attention. In particular, these thin display devices are implemented in the form of a touch screen panel, and are characterized by portability to various wearable devices as well as smart phones and tablet PCs. It is widely used in various smart devices.

Such portable touch screen panel-based display devices have a window cover for display protection on the display panel to protect the display panel from scratches or external impact, and in most cases, tempered glass for display is used as the window cover. Tempered glass for display is thinner than general glass, but it has high strength and is strong against scratches.

However, tempered glass has a disadvantage that it is not suitable for reducing the weight of portable devices due to its heavy weight, and it is difficult to implement an unbreakable property because it is vulnerable to external shock, and it is not bent over a certain level and is bendable. It is not suitable as a flexible display material having a foldable function.

Recently, various studies have been conducted on optical plastic covers that have strength or scratch resistance corresponding to tempered glass while securing flexibility and impact resistance. In general, the optical transparent plastic cover material that has more flexibility than tempered glass is polyethylene terephthalate (PET), polyethersulfone (PES), polyethylene naphthalate (PEN), polyacrylate (PAR), polycarbonate (PC). , polyimide (PI), and polyaramid (PA). However, in the case of these polymer plastic substrates, compared to tempered glass used as a window cover for display protection, not only exhibit insufficient physical properties in terms of hardness and scratch resistance, but also insufficient impact resistance. Therefore, various attempts are being made to supplement the physical properties required by coating the composite resin composition on these plastic substrates.

In the case of a general hard coating, a composition consisting of a resin containing a photocurable functional group such as (metha)acrylate or epoxy, a curing agent or a curing catalyst and other additives is used, and in particular, In the case of a composite resin, it can be used as a display protection window with improved hardness and scratch resistance by coating it on an optical plastic base film.

However, in the case of general (meth)acrylate or epoxy high-functional group photocurable composite resin, it is difficult to realize high hardness corresponding to tempered glass, and curl phenomenon due to shrinkage occurs greatly during curing, and flexibility is also There is a disadvantage in that it is not sufficient as a protective window substrate for application to a flexible display.

Korean Patent Application Laid-Open No. 2013-74167 discloses a plastic substrate.

Korea Patent Publication No. 2013-74167

An object of the present invention is to provide a composition capable of forming a hard coating layer having significantly improved hardness.

In addition, an object of the present invention is to provide a composition capable of forming a hard coating layer having excellent flexibility.

In addition, an object of the present invention is to provide a hard coat film having the hard coat layer.

1. A (meth)acrylate siloxane resin having a weight average molecular weight of 500 to 30,000 and a polydispersity index (PDI) of 2.0 to 4.0;

(meth) a crosslinking agent containing an acrylate-based compound;

colloidal silica containing a (meth)acrylate group on the surface and having an average particle diameter of 1 to 200 nm;

And comprising a photoinitiator, a composition for forming a hard coating layer.

2. The composition for forming a hard coating layer according to the above 1, wherein the (meth)acrylate-based compound is a compound represented by the following Chemical Formula 1:

[Formula 1]

(Wherein, R is a linear, branched or cyclic aliphatic hydrocarbon having 3 to 50 carbon atoms or an aromatic hydrocarbon having 6 to 50 carbon atoms, and the aliphatic hydrocarbon or aromatic hydrocarbon is at least selected from the group consisting of N, O and S. may contain one heteroatom,

X is a linear, branched or cyclic aliphatic hydrocarbon having 2 to 80 carbon atoms or an aromatic hydrocarbon having 6 to 80 carbon atoms including 2 to 20 (meth)acrylate groups, wherein the aliphatic hydrocarbon or aromatic hydrocarbon is N, O and may include at least one hetero atom selected from the group consisting of S,

n is an integer from 1 to 10).

3. In the above 1, the (meth) acrylate-based compound is pentaerythritol triacrylate, pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate, pentaerythritol tetraacrylate dipentaerythritol pentaacrylate, dipenta At least one selected from the group consisting of erythritol hexaacrylate, dipentaerythritol pentamethacrylate, dipentaerythritol hexamethacrylate, phosphazene acrylate and phosphazene methacrylate, a composition for forming a hard coating layer.

4. The composition for forming a hard coating layer according to the above 1, wherein the colloidal silica containing a (meth)acrylate group on the surface is surface-treated with a functional group represented by the following formula (2):

[Formula 2]

(Wherein, A is a 2 to 6 straight-chain or branched alkylene group,

B is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms,

"*" is a bond).

5. The composition of the above 1, wherein the siloxane resin has a weight average molecular weight of 1,000 to 20,000.

6. The composition of the above 1, wherein the siloxane resin has a weight average molecular weight of 5,000 to 15,000.

7. The composition for forming a hard coating layer according to the above 1, wherein the siloxane resin is polymerized by including a monomer having an aryl group in an amount of 10% by weight or less based on the total weight of the monomer.

8. The composition for forming a hard coat layer according to the above 1, wherein the siloxane resin has a UV absorption spectrum peak having a maximum absorbance at a wavelength of 200 to 250 nm.

9. The composition for forming a hard coat layer according to the above 1, wherein the (meth)acrylate-based compound is included in an amount of 5 to 70% by weight of the total weight of the composition for forming a hard coat layer.

10. The composition for forming a hard coat layer according to the above 1, wherein the colloidal silica is included in an amount of 5 to 70% by weight of the total weight of the composition for forming a hard coat layer.

11. A hard coat film comprising a substrate having a hard coat layer formed of the composition for forming a hard coat layer of any one of claims 1 to 10 on at least one surface.

12. The hard coating film of the above 11, wherein the rate of change of the chromaticity b value before and after standing for 1,000 hours at 85° C. and 90% relative humidity condition of the hard coating layer is within 5%.

13. An image display device having the hard coating film of 11 above.

The composition of the present invention can form a hard coating layer having significantly improved hardness.

In addition, the composition of the present invention can form a hard coating layer having excellent flexibility. Accordingly, the hard coating film having a hard coating layer of the present invention can secure excellent flexibility without a separate curl suppression layer.

1 is a schematic cross-sectional view of a hard coat film having a hard coat layer formed of the composition for forming a hard coat layer of the present invention.
Figure 2 schematically shows an embodiment of performing a bending test on a hard coating film having a hard coating layer formed of the composition for forming a hard coating layer of the present invention.
Figure 3 schematically shows an embodiment of performing a bending test on a hard coating film having a hard coating layer formed of the composition for forming a hard coating layer of the present invention.

The present invention relates to a (meth)acrylate siloxane resin having a weight average molecular weight of 500 to 30,000 and a polydispersity index (PDI) of 2.0 to 4.0; (meth) a crosslinking agent containing an acrylate-based compound; colloidal silica containing a (meth)acrylate group on the surface and having an average particle diameter of 1 to 200 nm; And by including a photoinitiator, it has remarkably improved hardness and relates to a composition for forming a hard coat layer capable of forming a hard coat layer having excellent flexibility.

Hereinafter, the present invention will be described in detail.

<Composition for forming a hard coat layer>

The composition for forming a hard coat layer of the present invention includes a (meth)acrylate-based siloxane resin, a crosslinking agent, colloidal silica, and a photoinitiator.

( meta ) Acrylates siloxane profit

The (meth)acrylate siloxane resin of the present invention means a siloxane resin having a (meth)acrylate group, and the (meth)acrylate is an alicyclic (meth)acrylate group, an aliphatic (meth)acrylate group, an aromatic It may be a (meth)acrylate group or a mixture thereof, preferably silsesquioxane having (meth)acrylate.

The (meth)acrylate siloxane resin according to the present invention has a weight average molecular weight of 500 to 30,000, preferably 1,000 to 20,000, and more preferably 5,000 to 15,000 in terms of securing high hardness and fairness at the same time.

The polydispersity index (PDI) of the (meth)acrylate siloxane resin is 2.0 to 4.0. If the polydispersity index is less than 2.0, it is difficult to simultaneously satisfy both the hardness and ductility of the hard coating layer, and if it exceeds 4.0, the physical properties related to ductility are overexpressed.

The composition for forming a hard coat layer of the present invention can significantly improve hardness by using a (meth)acrylate siloxane resin having a weight average molecular weight and a polydispersity index in the specific range. In addition, flexibility is remarkably improved, and bending deformation can be suppressed.

The (meth)acrylate siloxane resin according to the present invention is prepared through hydrolysis and condensation reaction between an alkoxysilane having a (meth)acrylate group alone or an alkoxysilane having a (meth)acrylate group and a heterogeneous alkoxysilane in the presence of water can be

Schemes 1 to 3 below schematically show hydrolysis and condensation reactions of alkoxysilanes in the presence of water and a catalyst.

[Scheme 1]

[Scheme 2]

[Scheme 3]

In Schemes 1 to 3, R is a straight-chain or branched alkyl group having 1 to 7 carbon atoms, R' is a straight-chain or branched alkyl group having 1 to 20 carbon atoms including a (meth)acrylate group, and 3 to 8 carbon atoms. A cycloalkyl group, an alkenyl group having 3 to 20 carbon atoms, an alkynyl group having 2 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an acryl group, a methacryl group, a halogen group, an amino group, a mercapto group, an ether group, an ester group, a carbonyl group, It may include at least one functional group selected from the group consisting of a carboxyl group, a vinyl group, a nitro group, a sulfone group, and an alkyd group.

Scheme 1 above shows that the alkoxy group of the alkoxy silane as a starting material is hydrolyzed by water to form a hydroxyl group. As shown in Scheme 2 or Scheme 3, the hydroxyl group formed through this forms a siloxane bond through a condensation reaction between the hydroxyl groups or alkoxy groups of other silanes. Therefore, the weight average molecular weight and molecular weight distribution (PDI) of the finally formed siloxane compound can be controlled by controlling the reaction rate, and the reaction temperature, the amount, type, and solvent of the catalyst can be major factors.

A catalyst is used to prepare a (meth)acrylate siloxane resin having a weight average molecular weight of 500 to 30,000 and a polydispersity index of 2.0 to 4.0 using the above reaction formula. Examples of the usable catalyst include acid catalysts such as hydrochloric acid, acetic acid, hydrogen fluoride, nitric acid, sulfuric acid chlorosulfonic acid, iodic acid, and phyllophosphoric acid; base catalysts such as ammonia, potassium hydroxide, sodium hydroxide, barium hydroxide, imidazole, n-butylamine, di-n-butylamine, tri-n-butylamine, ammonium perchlorate, and tetramethyl-ammonium hydroxide; and ion exchange resins such as Amberite IRA-400 and IRA-67, and may also be selected from the group consisting of combinations thereof.

The amount of the catalyst is not particularly limited, but in the case of an acid catalyst and a base catalyst, about 0.0001 to about 0.01 parts by weight may be added based on about 100 parts by weight of the alkoxy silane, and in the case of an ion exchange resin, about 1 to about 100 parts by weight of the alkoxy silane to about 10 parts by weight may be added, but may not be limited thereto.

The hydrolysis and condensation reaction may be carried out by stirring at room temperature for about 12 hours to about 7 days, but in order to promote the reaction, stirring may be performed at about 60° C. to about 100° C. for about 2 hours to about 72 hours. , which may not be limited thereto.

As can be seen in Schemes 1 to 3, when the reaction occurs, alcohol and water, which are by-products, are generated. By removing these, a reverse reaction can be reduced and a forward reaction can be induced, thereby controlling the reaction rate. In addition, when the reaction is completed, alcohol and water remaining in the siloxane resin may be removed by applying a condition of about 60° C. to about 100° C. under reduced pressure for about 10 minutes to about 60 minutes, but may not be limited thereto.

The alkoxy silane having a (meth)acrylate group used in the preparation of a (meth)acrylate siloxane resin according to an embodiment of the present invention may be exemplified by the following Chemical Formula A.

[Formula A]

R ¹ _n Si(OR ² ) _4-n

(Wherein, R ¹ is a linear or branched alkyl group having 1 to 6 carbon atoms substituted with a (meth)acrylate cycloalkyl group having 3 to 6 carbon atoms or an oxiranyl group, and may be interrupted by oxygen,

R ² is a straight-chain or branched alkyl group having 1 to 7 carbon atoms,

n is an integer from 1 to 3).

The alkoxysilane represented by the above formula (A) is not particularly limited, and examples thereof include 3-(methacroyloxy)propyltrimethoxysilane and the like. These can be used individually or in mixture of 2 or more types.

In one embodiment of the present application, the (meth)acrylate siloxane resin may be prepared by using an alkoxysilane having a (meth)acrylate alone, but also, a valence between an alkoxysilane having a (meth)acrylate and a heterogeneous alkoxysilane It may be prepared through decomposition and condensation reaction, but may not be limited thereto.

The heterogeneous alkoxy silane may be used by selecting one or more types from the alkoxy silanes represented by the following formula (B):

[Formula B]

R ³ _m Si(OR ⁴ ) _4-m ;

(wherein, R ³ is an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 8 carbon atoms, an alkenyl group having 3 to 20 carbon atoms, an alkynyl group having 2 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an acrylic group, meta It may include at least one functional group selected from the group consisting of a kryl group, a halogen group, an amino group, a mercapto group, an ether group, an ester group, a carbonyl group, a carboxyl group, a vinyl group, a nitro group, a sulfone group and an alkyd group,

R ⁴ is a straight-chain or branched alkyl group having 1 to 7 carbon atoms, and m is an integer of 0 to 3).

The alkoxy silane represented by the formula (B) is not particularly limited, and for example, N-(3-acryloxy-2-hydroxypropyl)-3-aminopropyltrimethoxysilane, N-(3-acryloxy- 2-hydroxypropyl)-3-aminopropyltriethoxysilane, N-(3-acryloxy-2-hydroxypropyl)-3-aminopropyltripropoxysilane, 3-acryloxypropylmethylbis(trime Toxy)silane, 3-acryloxypropyltriethoxysilane, 3-acryloxypropyltripropoxysilane, 3-(meth)acryloxypropyltriethoxysilane, 3-(meth)acryloxypropyltripropoxysilane, etc. can be heard These can be used individually or in mixture of 2 or more types.

Preferably, the silsesquioxane resin according to the present invention may be polymerized by including a small amount of a monomer having an aryl group. For example, the monomer having an aryl group may be polymerized by including 10% by weight or less of the total weight of the monomer. If the content of the monomer having an aryl group is more than 10% by weight based on the total weight of the monomer, yellowing of the hard coating layer may occur.

The silsesquioxane resin according to the present invention may be polymerized without including a monomer having an aryl group in a small amount, and most preferably, a monomer having an aryl group in order to suppress yellowing.

In addition, the silsesquioxane resin may have a UV absorption spectrum peak exhibiting a maximum absorbance at a wavelength of 200 to 250 nm. When the maximum absorbance is shown at the above wavelength, yellowing of the hard coating layer prepared with the composition of the present invention can be minimized.

The content of the (meth)acrylate siloxane resin is not particularly limited, and for example, may be included in an amount of 5 to 70% by weight based on the total weight of the composition for forming a hard coat layer. When the content of the (meth)acrylate siloxane resin is within the above range, it is possible to form a hard coating layer exhibiting a hardness improvement effect and excellent flexural properties.

crosslinking agent

The crosslinking agent according to the present invention includes a (meth)acrylate-based compound, and is a component that promotes crosslinking to exhibit excellent hardness and flexibility.

The (meth)acrylate-based compound of the present invention refers to a compound including a (meth)acrylate group, and (meth)acrylate refers to an acrylate or a methacrylate.

The (meth)acrylate-based compound of the present invention is characterized in that it promotes a photocuring reaction and has excellent hardness by including a (meth)acrylate group in the molecule.

The (meth)acrylate-based compound is not particularly limited as long as it includes a (meth)acrylate group, and may include, for example, at least one of a (meth)acrylate monomer and a (meth)acrylate oligomer. As used herein, the term oligomer refers to a case in which the number of repeating units is 2 to 10 or less.

The (meth)acrylate monomer is not particularly limited as long as it does not deviate from the object of the present invention, and specifically, 2-ethylhexyl acrylate, octadecyl acrylate, isodecyl acrylate, and 2-phenoxyethyl acrylate , lauryl acrylate, stearyl acrylate, behenyl acrylate, tridecyl methacrylate, nonylphenolethoxylate monoacrylate, β-carboxyethyl acrylate, isobornyl acrylate, tetrahydrofurfuryl acrylate, tetrahydrofurfuryl methacrylate, 4-butylcyclohexyl acrylate, dicyclopentenyl acrylate, dicyclopentenyl oxyethyl acrylate, ethoxyethoxyethyl acrylate, ethoxylated monoacrylate, 1, 6-hexanediol diacrylate, triphenyl glycol diacrylate, butanediol diacrylate, 1,3-butylene glycol dimethacrylate, 1,6-hexanediol dimethacrylate, neopentyl glycol diacrylate, Ethylene glycol dimethacrylate, diethylene glycol diacrylate, diethylene glycol dimethacrylate, tetraethylene glycol, diacrylate, tetraethylene glycol dimethacrylate, triethylene glycol diacrylate, triethylene glycol dimethacrylate acrylate, polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, diphoropylene glycol diacrylate, ethoxylated neopentyl glycol diacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, Pentaerythritol triacrylate, pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate, pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, dipentaerythritol pentamethacrylate, dipenta Erythritol hexamethacrylate, phosphazene acrylate, phosphazene methacrylate, ethoxylated triacrylate, tris(2-hydroxyethyl)isocyanurate triacrylate, dipentaerythritol pentaacrylate, ditrimethyl Allpropane tetraacrylate, alcohol sylated tetraacrylate, etc. are mentioned. Preferably, pentaerythritol triacrylate, pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate, pentaerythritol tetraacrylate dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, dipentaerythritol pentamethacrylate rate, dipentaerythritol hexamethacrylate, phosphazene acrylate, phosphazene methacrylate, and the like. These can be used individually or in mixture of 2 or more types, respectively.

The (meth)acrylate oligomer is not particularly limited within the scope not departing from the object of the present invention, and specifically, polyester (meth)acrylate, urethane (meth)acrylate, epoxy (meth)acrylate, polyether (meth)acrylate etc. are mentioned. These can be used individually or in mixture of 2 or more types, respectively.

Since the (meth)acrylate-based compound preferably contains 6 to 15 (meth)acrylate groups in the molecule in order to have excellent hardness and flexural properties, an oligomer may be used in this aspect, and more preferably, urethane (meth) ) acrylates can be used.

Specific examples of the urethane (meth)acrylate may include a compound represented by the following formula (1).

[Formula 1]

(Wherein, R is a linear, branched or cyclic aliphatic hydrocarbon having 3 to 50 carbon atoms or an aromatic hydrocarbon having 6 to 50 carbon atoms, and the aliphatic hydrocarbon or aromatic hydrocarbon is at least selected from the group consisting of N, O and S. may contain one heteroatom,

X is a linear, branched or cyclic aliphatic hydrocarbon having 2 to 80 carbon atoms or an aromatic hydrocarbon having 6 to 80 carbon atoms including 2 to 20 (meth)acrylate groups, wherein the aliphatic hydrocarbon or aromatic hydrocarbon is N, O and may include at least one hetero atom selected from the group consisting of S,

n is an integer from 1 to 10).

The urethane (meth)acrylate has a lower viscosity than other oligomers having the same or similar molecular weight, and when photocuring by mixing with the (meth)acrylate-based monomer, it can maintain high hardness while reducing shrinkage of the film. Suitable for hard coating.

The (meth)acrylate oligomer is prepared by reacting a (meth)acrylate monomer containing a hydroxyl group with an organic compound having two or more isocyanate groups in a molecule.

The organic compound having two or more isocyanate groups in the molecule is, for example, 1,4-diisocyanatobutane, 1,6-diisocyanatohexane, 1,8-diisocyanatooctane, 1,12-diisocyanate. Decane, 1,5-diisocyanato-2-methylpentane, trimethyl-1,6-diisocyanatohexane, 1,3-bis(isocyanatomethyl)cyclohexane, trans-1,4-cyclohexenediisocyanate , 4,4'-methylenebis(cyclohexylisocyanate), isophorone diisocyanate, toluene-2,4-diisocyanate, toluene-2,6-diisocyanate, xylene-1,4-diisocyanate, tetramethylxyl Ren-1,3-diisocyanate, 1-chloromethyl-2,4-diisocyanate, 4,4'-methylenebis(2,6-dimethylphenylisocyanate), 4,4'-oxybis(phenylisocyanate), At least one kind may be selected from the group consisting of trifunctional isocyanate derived from hexamethylene diisocyanate, and trimethanol adduct toluene diisocyanate.

The (meth)acrylate monomer containing a hydroxyl group is, for example, 2-hydroxyethyl (meth)acrylate, 2-hydroxyisopropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, caprolactone. At least one selected from the group consisting of a ring-opening hydroxyacrylate, a pentaerythritol tri/tetra (meth) acrylate mixture, and a dipentaerythritol penta/hexa (meth) acrylate mixture may be selected.

In addition, the composition for forming a hard coat layer of the present invention includes the (meth)acrylate-based compound according to the present invention to have superior hardness and flexural properties without using a separate thermosetting agent.

The content of the crosslinking agent is not particularly limited, and for example, may be included in an amount of 5 to 70% by weight based on the total weight of the composition for forming a hard coat layer. When the content of the epoxy compound is within the above range, it is possible to further improve the curing efficiency of the composition to form a hard coating layer having excellent hardness and exhibiting excellent flexural properties.

colloidal silica

The composition for forming a hard coating layer of the present invention includes a (meth)acrylate group on the surface and colloidal silica having an average particle diameter of 1 to 200 nm, thereby significantly improving hardness while maintaining excellent transparency of the hard coating layer.

The colloidal silica according to the present invention includes a (meth)acrylate group on the surface to form a covalent bond with the (meth)acrylate group of the (meth)acrylate-based siloxane resin to be described later and the (meth)acrylate group of the colloidal silica, ( The bonding strength between the meth)acrylate-based siloxane resin and colloidal silica is strengthened to improve the hardness of the hard coating layer.

The colloidal silica according to the present invention can be used without particular limitation as long as it contains a (meth)acrylate group on the surface, for example, a colloidal solution in which colloidal silica is dispersed in a solvent, or fine powder colloidal silica that does not contain a dispersion solvent, etc. What surface-treated so that it may contain (meth)acrylate group is mentioned.

Examples of the solvent for dispersing colloidal silica include alcohols such as water, methanol, ethanol, isopropanol, and n-butanol; polyhydric alcohols and derivatives thereof such as ethylene glycol, ethylene glycol monoethyl ether, and propylene glycol monomethyl ether; ketones such as methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone; esters such as ethyl acetate and butyl acetate; non-polar solvents such as toluene and xylene; (meth)acrylates such as 2-hydroxybutyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate: and other organic solvents can be used. have.

The colloidal silica having a (meth)acrylate group on the surface of the present invention may be surface-treated with a functional group represented by the following Chemical Formula 2.

[Formula 2]

(Wherein, A is a 2 to 6 straight-chain or branched alkylene group,

B is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms,

"*" is a bond).

As a method of surface-treating colloidal silica to include a (meth)acrylate group on the silica surface, a known method may be used without any particular limitation, and examples thereof include a dry method and a wet method. The dry method is a method in which silica powder is stirred at high speed using a stirrer and uniformly dispersed with a treatment agent such as a coupling agent for treatment. The wet method is a method of processing by adding a processing agent such as a coupling agent to a slurry obtained by dispersing silica in a solvent and stirring.

More specifically, a method of surface-treating colloidal silica to include (meth)acrylate groups on the surface of the silica using a silane coupling agent containing (meth)acrylate groups on the surface thereof is exemplified.

The silane coupling agent can be used without particular limitation that it contains a (meth)acrylate group, for example, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-methacryl and oxypropyltriethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ-methacryloxypropyltris(methoxyethoxy)silane, and γ-acryloxypropyltrimethoxysilane.

These silane coupling agents can be used individually or in mixture of 2 or more types.

In addition, the colloidal silica according to the present invention has an average particle diameter of 1 to 200 nm, and by including such nano-sized silica particles, the transmittance is not affected, thereby improving the hardness while maintaining excellent transparency. If the average particle diameter is less than 1 nm, the hardness improvement effect is insignificant, and if it exceeds 200 nm, it may act as a foreign material of the hard coating layer. The average particle diameter of the colloidal silica may be preferably 1 to 100 nm, and more preferably 5 to 30 nm. In the above range, it is possible to prevent a decrease in transparency while having an excellent effect of improving hardness.

The content of colloidal silica according to the present invention is not particularly limited, and may be included, for example, in an amount of 5 to 70% by weight based on the total weight of the composition for forming a hard coat layer. When the content of colloidal silica is within the above range, it is possible to form a hard coating layer that exhibits a hardness improvement effect, maintains an appropriate viscosity, exhibits excellent coating properties, and exhibits excellent flexural properties.

photoinitiator

The composition for forming a hard coat layer of the present invention further comprises a photoinitiator.

The photoinitiator may be used without limitation as long as it can initiate photopolymerization of the (meth)acrylate siloxane resin and the (meth)acrylate-based compound, for example, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin Phosphorus isopropyl ether, benzoin-n-butyl ether, benzoin isobutyl ether, acetophenone, hydroxydimethylacetophenone, dimethylaminoacetophenone, dimethoxy-2-phenylacetophenone, 3-methylacetophenone, 2, 2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 4-chronolocetophenone, 4,4-dimethoxyacetophenone, 2-hydroxy-2-methyl-1 -Phenylpropan-1-one, 4-hydroxycyclophenylketone, 1-hydroxycyclohexylphenylketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-propane-1 -one, 4- (2-hydroxyethoxy) phenyl-2- (hydroxy-2-propyl) ketone, benzophenone, p-phenylbenzophenone, 4,4-diaminobenzophenone, 4,4'- Diethylaminobenzophenone, dichlorobenzophenone, anthraquinone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-t-butylanthraquinone, 2-aminoanthraquinone, 2-methylthioxanthone, 2-ethylthi Oxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, benzyldimethylketal, diphenylketonebenzyldimethylketal, acetophenonedimethylketal, p-dimethylaminobenzoic acid ester, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, fluorene, triphenylamine, carbazole, etc. are mentioned. These can be used individually or in mixture of 2 or more types.

The content of the photoinitiator is not particularly limited, and for example, may be included in an amount of 0.1 to 20% by weight of the total weight of the composition for forming a hard coating layer. When the content of the photoinitiator is within the above range, it is possible to maintain excellent curing efficiency of the composition and prevent deterioration of physical properties due to residual components after curing.

The composition for forming a hard coat layer of the present invention may further include a solvent.

The solvent according to the present invention is not particularly limited, and solvents known in the art may be used, for example, alcohol-based (methanol, ethanol, isopropanol, butanol, methyl cellulose, ethyl sol-sorb, etc.), ketone-based (methyl Ethyl ketone, methyl butyl ketone, methyl isobutyl ketone, diethyl ketone, dipropyl ketone, cyclohexanone, etc.), hexane type (hexane, heptane, octane, etc.), benzene type (benzene, toluene, xylene, etc.) can be used These can be used individually or in mixture of 2 or more types.

The content of the solvent according to the present invention is not particularly limited, and for example, may be included in an amount of 10 to 60% by weight of the total weight of the composition for forming a hard coat layer. When the content of the solvent is within the above range, it is possible to maintain an appropriate viscosity, so that the workability is excellent, the thickness control of the coating film is easy, and the process speed can be improved.

If necessary, the composition for forming a hard coat layer of the present invention may further include a lubricant to improve winding efficiency, blocking resistance, abrasion resistance, and scratch resistance.

The type of lubricant according to the present invention is not particularly limited, and examples thereof include waxes such as polyethylene wax, paraffin wax, synthetic wax or montan wax; synthetic resins such as silicone-based resins and fluorine-based resins; and the like. These can be used individually or in mixture of 2 or more types.

The content of the lubricant according to the present invention is not particularly limited, and for example, may be included in an amount of 0.1 to 5% by weight of the total weight of the composition for forming a hard coat layer. When the content is within the above range, while imparting excellent blocking resistance, friction resistance and scratch resistance, the transparency can also be excellently maintained.

In addition, if necessary, additives such as antioxidants, UV absorbers, light stabilizers, thermal polymerization inhibitors, leveling agents, surfactants, lubricants, and antifouling agents may be further included.

<Hard coating film>

In addition, the present invention provides a hard coating film 100 comprising a substrate 110 having a hard coating layer 120 formed of the composition for forming a hard coating layer on at least one surface.

The substrate 110 according to the present invention preferably has excellent transparency, mechanical strength, thermal stability, moisture shielding property, isotropy, etc., for example, a polyester-based resin such as polyethylene terephthalate, polyethylene isophthalate, and polybutylene terephthalate. ; Cellulose resins, such as a diacetyl cellulose and a triacetyl cellulose; polycarbonate-based resin; acrylic resins such as polymethyl (meth)acrylate and polyethyl (meth)acrylate; styrenic resins such as polystyrene acrylonitrile-styrene copolymer; polyolefin-based resins such as polyethylene, polypropylene, polyolefin-based resins having a cyclo-based or norbornene structure, and ethylenepropylene copolymers; polyimide-based resin; polyaramid-based resin; polyether sulfone-based resin; It may be a substrate made of a sulfone-based resin or the like. These resins can be used individually or in mixture of 2 or more types.

The thickness of the substrate 110 is not particularly limited, and may be, for example, 10 to 250 μm.

The hard coat layer 120 is formed by applying and curing the composition for forming the hard coat layer, and the application is performed by a known method such as a die coater, air knife, reverse roll, spray, blade, casting, gravure, spin coating, etc. can be

In the case of curing, the method is not particularly limited, and for example, photocuring or thermal curing may be performed alone, or thermal curing after photocuring, photocuring after thermal curing, or the like may be used.

The thickness of the hard coating layer 120 is not particularly limited, and may be, for example, 10 to 100 μm. When the thickness is within the above range, the curling phenomenon hardly occurs and the hard coating layer 120 having excellent hardness can be obtained.

The hard coating layer 120 according to the present invention is formed of the composition for forming the hard coating layer and has significantly improved hardness. The hardness may vary depending on the content, type, etc. of the individual compositions, but the pencil hardness may be 5H or more, and may be 9H or more at the maximum when each of the above-described compositions is used in combination in a desired amount.

In addition, the flexibility is remarkably improved, and the bending deformation is very small.

In addition, even when exposed to high temperature, high humidity conditions for a long time, it is possible to minimize the occurrence of yellowing. For example, the rate of change of the chromaticity b value before and after standing for 1,000 hours in a moist heat resistant condition of 85° C. and 90% relative humidity may be within 5%.

The hard coating film 100 of the present invention has a very high surface hardness and at the same time has a hard coating layer 120 having excellent flexibility, and is lighter than tempered glass and has excellent impact resistance. It can be used preferably.

In addition, the present invention provides an image display device having the hard coating film (100).

The hard coating film 100 may be used as an outermost window substrate of an image display device, and the image display device is a conventional liquid crystal display device, an electroluminescence display device, a plasma display device, a field emission display device, etc. Various image display devices. can

Hereinafter, examples will be given to describe the present invention in detail.

manufacturing example One. Silsesquioxane Synthesis of resins

3-(Metacroyloxy)propyltrimethoxysilane (MAPTMS, TCI) and water (H2O, Sigma-Aldrich) were mixed in a ratio of 24.85g: 2.70 g (0.1 mol: 0.15mol) to 250 mL 2 placed in a neck flask. Then, 2 g of Amberlyst IRA-400 (Cl) catalyst and 100 mL of MEK were added to the mixture, and the mixture was stirred at 25° C. for 24 hours. Thereafter, it was filtered using a 0.45 μm Teflon filter to obtain an acrylic siloxane resin. The molecular weight of the resin was measured using gel permeation chromatography (GPC).

manufacturing example 2. Silsesquioxane Synthesis of resins

3-(methacroyloxy)propyltrimethoxysilane (MAPTMS, TCI) and water (H2O, Sigma-Aldrich) were mixed in a ratio of 24.85g: 2.70 g (0.1 mol: 0.15mol) to 100 mL 2 placed in a neck flask. Then, 1 g of Amberlyst IRA-400 (Cl) catalyst and 50 mL of MEK were added to the mixture, and the mixture was stirred at 70° C. for 24 hours. Thereafter, it was filtered using a 0.45 μm Teflon filter to obtain an acrylic siloxane resin. The molecular weight of the resin was measured using gel permeation chromatography (GPC).

manufacturing example 3. Silsesquioxane Synthesis of resins

19.88g: 4.81g of 3-(methacroyloxy)propyltrimethoxysilane (MAPTMS, TCI), phenyltrimethoxysilane (PTMS, Sigma-Aldrich), and water (H2O, Sigma-Aldrich): 2.70 g (0.08 mol: 0.02 mol: 0.15 mol) was mixed in a ratio and put into a 250 mL 2 neck flask. Then, 1 g of Amberlyst IRA-400 (Cl) catalyst was added to the mixture and stirred at 70° C. for 24 hours. Thereafter, a siloxane resin was obtained by filtration using a 0.45 μm Teflon filter, and the molecular weight was measured using gel permeation chromatography (GPC).

manufacturing example 4. Silsesquioxane Synthesis of resins

14.91g: 9.62g of 3-(methacroyloxy)propyltrimethoxysilane (MAPTMS, TCI), phenyltrimethoxysilane (PTMS, Sigma-Aldrich), and water (H2O, Sigma-Aldrich): 2.70 g (0.06 mol: 0.04 mol: 0.15 mol) was mixed in a ratio and put in a 100 mL 2 neck flask. Then, 1 g of Amberlyst IRA-400 (Cl) catalyst and 50 mL of MEK were added to the mixture, and the mixture was stirred at 70° C. for 24 hours. Thereafter, it was filtered using a 0.45 μm Teflon filter to obtain an acrylic siloxane resin. The molecular weight of the resin was measured using gel permeation chromatography (GPC).

manufacturing example 5. Silsesquioxane Synthesis of resins

3-(Metacroyloxy)propyltrimethoxysilane (MAPTMS, TCI) and water (H2O, Sigma-Aldrich) were mixed in a ratio of 24.85g: 2.70 g (0.1 mol: 0.15mol) to 250 mL 2 placed in a neck flask. Then, 2 g of Amberlyst IRA-400 (Cl) catalyst and 100 mL of MEK were added to the mixture, and the mixture was stirred at 50° C. for 72 hours. Thereafter, it was filtered using a 0.45 μm Teflon filter to obtain an acrylic siloxane resin. The molecular weight of the resin was measured using gel permeation chromatography (GPC).

manufacturing example 6. Silsesquioxane Synthesis of resins

3-(Metacroyloxy)propyltrimethoxysilane (MAPTMS, TCI) and water (H2O, Sigma-Aldrich) were mixed in a ratio of 24.85g: 2.70 g (0.1 mol: 0.15mol) to 250 mL 2 placed in a neck flask. Then, 2 g of Amberlyst IRA-400 (Cl) catalyst and 100 mL of MEK were added to the mixture, and the mixture was stirred at 70° C. for 24 hours. Thereafter, it was filtered using a 0.45 μm Teflon filter to obtain an acrylic siloxane resin. The molecular weight of the resin was measured using gel permeation chromatography (GPC).

manufacturing example 7. ( meta ) Acrylates synthesis of compounds

88.26 parts by weight of 4,4'-dicyclohexyldiisocyanate (H ¹² -MDI, Bayer Corporation), 6.27 parts by weight of a dipentaerythritol penta/hexaacrylate mixture (KAYARAD, Nippon Kayaku Corporation), dibutyl tin die 4.97 parts by weight of laulate (FASCAT 4202, Akema) and 0.5 parts by weight of methoxyhydroquinone (HQMME, Eastman) were added at room temperature, and the reaction temperature was raised to 90° C. while stirring. After reacting at 90° C. for 12 hours, the reaction was terminated when the characteristic peak of isocyanate in the infrared spectral spectrum of 2260 cm ^{−1 completely disappeared.}

manufacturing example 8. ( meta ) Acrylates synthesis of compounds

Bisphenol A epoxy (YD128, Kukdo Chemical), 100 parts by weight, acrylic acid (Aldrich) 27 parts by weight, triphenylphosphine (TPP, Aldrich) 3 parts by weight, methoxy hydroquinone (HQMME, Eastman) 0.5 parts by weight It was added at room temperature, and the reaction temperature was raised to 120 °C while stirring. After reacting at 120° C. for 6 hours, the reaction was terminated when the epoxy characteristic peak (3.3 ppm) disappeared by NMR.

manufacturing example 9. Surface treatment of colloidal silica

90 wt% of MEK-ST (Nissan Chemical Industries, Ltd., organo silica sol (solid content 30%)) and 10 wt% of γ-methacryloxypropyltrimethoxysilane were added to a round-bottom flask equipped with a stirrer and cooling tube. It was stirred at room temperature for 6 hours to obtain colloidal silica having an average particle diameter of 12 nm containing (meth)acrylate on the surface.

division Mn Mw PDI (Mw/Mn) Equivalent ratio (%) Maximum UV absorption wavelength (nm) Preparation Example 1 650 1980 3.05 89 220nm Preparation 2 2300 5500 2.39 89 217nm Preparation 3 1771 5500 3.11 89 245nm Preparation 4 3250 7530 2.32 89 325nm Preparation 5 2590 10500 4.05 89 227nm Preparation 6 2804 5206 1.86 89 224nm

Example and comparative example

A composition for forming a hard coat layer having the composition and content shown in Table 2 was prepared.

division Siloxane resin photoinitiator crosslinking agent colloidal silica menstruum ingredient weight% ingredient weight% ingredient weight% ingredient weight% ingredient weight% Example 1 Preparation Example 1 20 A 5 B-1 20 C-1 30 D 25 Example 2 Preparation 2 20 A 5 B-1 20 C-1 30 D 25 Example 3 Preparation 3 20 A 5 B-1 20 C-1 30 D 25 Example 4 Preparation 4 20 A 5 B-1 20 C-1 30 D 25 Example 5 Preparation Example 1 20 A 5 B-2 20 C-1 30 D 25 Example 6 Preparation 2 20 A 5 B-2 20 C-1 30 D 25 Example 7 Preparation 2 8 A One B-1 75 C-1 8 D 8 Example 8 Preparation 2 8 A One B-1 8 C-1 75 D 8 Comparative Example 1 Preparation Example 1 20 A 5 B-3 20 C-1 30 D 25 Comparative Example 2 Preparation 2 20 A 5 B-1 20 C-2 30 D 25 Comparative Example 3 Preparation Example 1 20 A 5 - - C-1 30 D 25 Comparative Example 4 Preparation 2 20 A 5 B-1 20 - - D 25 Comparative Example 5 Preparation 5 20 A 5 B-1 20 C-1 30 D 25 Comparative Example 6 Preparation 6 20 A 5 B-1 20 C-1 30 D 25 A: 1-hydroxyhexylphenyl ketone
B-1: the compound of Preparation 7
B-2: the compound of Preparation 8
B-3: N-vinylpyrrolidine
C-1: colloidal silica of Preparation 9
C-2: Colloidal silica with an average particle diameter of 12 nm without surface treatment (Aelozil)
D: methyl ethyl ketone

Experimental example

The composition for forming the hard coating layer of Examples and Comparative Examples was applied to a 125um PET film (SKC) using a Meyer bar, cured at 100°C for 10 minutes, and UV-irradiated at 1J/cm2 using a high-pressure mercury lamp, followed by UV irradiation at 150°C for 10 minutes. After curing for minutes, a hard coating layer having a thickness of 50 μm was obtained.

(1) Measurement of pencil hardness

The hardness of the hard coating layer was measured using a pencil hardness meter according to JIS K5600.

(2) flexibility evaluation

As shown in FIG. 2, the hard coating film prepared in the experimental example was _{wound 180° on a cylinder with a bottom radius of R 1} so that the hard coating layer was on the inside, and then returned to the original position. _{The minimum R 1 in} which no flexural deformation was observed was recorded.

And, as shown in FIG. 3 , it was wound at 180° so that the hard coating layer came to the outside on the cylinder of the _{base radius R 2 , and after returning it to its original position, the minimum R 2 in} which no bending deformation was observed was recorded.

(3) UV absorption peak

The absorbance of each UV wavelength band of the silsesquioxane resin prepared in Preparation Example was measured using a UV-Vis spectrometer (Shimadzu).

(4) yellowing Whether the phenomenon occurs

Samples prepared in Examples and Comparative Examples were sampled in a size of 10 mm * 10 mm and left for 1,000 hours in a high-temperature, high-humidity chamber at 85 ° C. and 90% relative humidity. was measured using

division pencil hardness Flexibility (mm) Chromaticity b value change rate (%) R ₁ R ₂ Example 1 9H 8 15 1.8 Example 2 9H 7 15 1.7 Example 3 9H 11 20 4.5 Example 4 9H 15 23 4.9 Example 5 8H 5 12 4.2 Example 6 8H 6 11 4.4 Example 7 7H 13 22 2.1 Example 8 7H 12 24 2.2 Comparative Example 1 5H 10 17 3.8 Comparative Example 2 5H 21 40 2.0 Comparative Example 3 4H 31 51 2.3 Comparative Example 4 5H 16 32 3.1 Comparative Example 5 5H 18 31 2.5 Comparative Example 6 5H 32 63 2.3

Referring to Table 3, the hard coating film having a hard coating layer prepared from the compositions of Examples 1 to 8 exhibited excellent hardness and flexibility. In addition, it was confirmed that the yellowing phenomenon was minimized because the change rate of the chromaticity b value was small even after heat-and-moisture treatment.

However, the hard coating film having a hard coating layer prepared from the compositions of Comparative Examples 1 to 6 was significantly inferior in hardness or flexibility.

100: hard coating film 110: substrate
120: hard coating layer

Claims (13)

(meth)acrylate siloxane resin having a weight average molecular weight of 1,000 to 20,000 and a polydispersity index (PDI) of 2.0 to 4.0;
(meth) a crosslinking agent containing an acrylate-based compound;
colloidal silica containing a (meth)acrylate group on the surface and having an average particle diameter of 1 to 200 nm;
and a photoinitiator,
The (meth) acrylate-based compound is a compound represented by the following formula (1), a composition for forming a hard coating layer:
[Formula 1]

(Wherein, R is a linear, branched or cyclic aliphatic hydrocarbon having 3 to 50 carbon atoms or an aromatic hydrocarbon having 6 to 50 carbon atoms, and the aliphatic hydrocarbon or aromatic hydrocarbon is at least selected from the group consisting of N, O and S. may contain one heteroatom,
X is a linear, branched or cyclic aliphatic hydrocarbon having 2 to 80 carbon atoms or an aromatic hydrocarbon having 6 to 80 carbon atoms including 2 to 20 (meth)acrylate groups, wherein the aliphatic hydrocarbon or aromatic hydrocarbon is N, O and may include at least one hetero atom selected from the group consisting of S,
n is an integer from 1 to 10).
delete The method according to claim 1, wherein the (meth) acrylate-based compound is pentaerythritol triacrylate, pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate, pentaerythritol tetraacrylate dipentaerythritol pentaacrylate, dipentaerythritol hexa At least one selected from the group consisting of acrylate, dipentaerythritol pentamethacrylate, dipentaerythritol hexamethacrylate, phosphazene acrylate and phosphazene methacrylate, a composition for forming a hard coating layer.
The composition for forming a hard coating layer according to claim 1, wherein the colloidal silica having a (meth)acrylate group on the surface is surface-treated with a functional group represented by the following formula (2):
[Formula 2]

(Wherein, A is a 2 to 6 straight-chain or branched alkylene group,
B is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms,
"*" is a bond).
delete The composition of claim 1, wherein the siloxane resin has a weight average molecular weight of 5,000 to 15,000.
The composition for forming a hard coat layer according to claim 1, wherein the siloxane resin is polymerized by including a monomer having an aryl group in an amount of 10% by weight or less based on the total weight of the monomer.
The composition for forming a hard coating layer according to claim 1, wherein the siloxane resin has a UV absorption spectrum peak having a maximum absorbance at a wavelength of 200 to 250 nm.
The method according to claim 1, wherein the (meth) acrylate-based compound is included in 5 to 70% by weight of the total weight of the composition for forming a hard coat layer, the composition for forming a hard coat layer.
The composition for forming a hard coat layer according to claim 1, wherein the colloidal silica is included in an amount of 5 to 70% by weight of the total weight of the composition for forming a hard coat layer.
A hard coating film comprising a substrate having a hard coating layer formed of the composition for forming a hard coating layer of any one of claims 1, 3, 4, 6 to 10 on at least one surface.
The method according to claim 11, wherein the hard coating layer is 85 ℃, 90% relative humidity conditions, the change rate of the chromaticity b value before and after 1,000 hours of standing within 5%, the hard coating film.
An image display device having the hard coating film of claim 11 .

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