KR102315000B1 - Hard coating film and image display device using the same - Google Patents

Abstract

The present invention provides a hard coating film comprising a hard coating layer on at least one surface of a substrate, wherein the substrate is a polyimide-based substrate having a glass transition temperature (Tg) of 230° C. or higher, and the Martens hardness of the hard coating layer is 150 to 250N/mm ² , and the elongation of the hard coating film is 8% or more, and relates to a hard coating film excellent in pencil hardness, scratch resistance and flex resistance.

Description

Hard coating film and image display device including the same

The present invention relates to a hard coating film and an image display device including the same.

As a protective film for image display devices such as displays, monitors, and touch panels, hard coating properties (scratch resistance), antistatic properties (prevention of dust adhesion, prevention of disorder of orientation due to charging of liquid crystals), antireflection properties (improving visibility) , anti-glare, anti-fouling (prevention of fingerprint adhesion), and the like optical laminates are known, among them, a hard coating film having a hard coating for protecting the surface of the image display device is widely used.

In addition, in recent years, flexible displays that can maintain display performance as they are even when bent like paper by using flexible materials such as plastics instead of the existing inflexible glass substrates are rapidly emerging as next-generation display devices. There is a need for development of a hard coating film having high abrasion resistance and excellent flexibility.

In this regard, Korean Patent Registration No. 10-1573973 discloses that in an optical laminate in which at least a hard coat layer is formed on a light-transmitting substrate, the hard coat layer is a polyfunctional (meth)acrylate-based UV-curable resin, ultraviolet light. The composition for a hard coat layer comprising an absorber and a photopolymerization initiator is cured by UV irradiation, and the hard coat layer has a Martens hardness of 230 to 320N/mm ² on the surface opposite to the light-transmissive substrate, and An optical laminate having a Martens hardness of 160 to 250 N/mm ^{2 on the light-transmissive substrate side is described.}

In addition, Korean Patent Application Laid-Open No. 10-2009-0044089 discloses a hard coating composition comprising a urethane acrylate oligomer having a molecular weight of 500 to less than 10,000, a polyfunctional acrylate monomer, and silica.

However, since the above patents do not recognize any method for improving the flexible characteristics to which repetitive stress is applied, it is difficult to apply them to the recently requested flexible image display device.

Republic of Korea Patent No. 10-1573973 (2015.12.02, Dainippon Insatsu Co., Ltd.) Republic of Korea Patent Publication No. 10-2009-0044089 (2009.05.07, Kumho Petrochemical Co., Ltd.)

An object of the present invention is to provide a hard coating film excellent in pencil hardness and scratch resistance and also excellent in bending resistance and an image display device including the same in order to solve the above problems.

The hard coating film of the present invention for achieving the above object includes a hard coating layer on at least one surface of a substrate, and the substrate is a polyimide-based substrate having a glass transition temperature (Tg) of 230° C. or higher, and the martens of the hard coating layer The hardness is 150 to 250N/mm ² , and the elongation of the hard coating film is 8% or more.

In addition, the window of the present invention is characterized in that it comprises the above-described hard coating film.

In addition, the window laminate of the present invention is characterized in that it includes the above-described window.

In addition, the image display device of the present invention is characterized in that it includes the above-described window laminate.

The hard coating film according to the present invention has excellent pencil hardness and scratch resistance, and also has excellent bending resistance.

In addition, the window of the present invention has the same advantages as described above by including the hard coating film of the present invention.

In addition, the window laminate of the present invention has the same advantages as described above by including the window of the present invention.

In addition, the image display apparatus of the present invention has the same advantages as described above by including the window of the present invention.

In the present invention, when a member is said to be located "on" another member, this includes not only a case in which a member is in contact with another member but also a case in which another member is present between the two members.

In the present invention, when a part "includes" a certain component, this means that other components may be further included rather than excluding other components unless otherwise stated.

Hereinafter, the present invention will be described in more detail.

< hard coating Film>

The hard coating film according to an aspect of the present invention includes a hard coating layer on at least one surface of a substrate, and the substrate is a polyimide-based substrate having a glass transition temperature (Tg) of 230° C. or higher, and the Martens hardness of the hard coating layer is 150 to 250N/mm ² , and the elongation of the hard coating film is characterized in that it is 8% or more, and more specifically, the elongation may be 8 to 20%. As such, the hard coating film of the present invention has the advantage of excellent pencil hardness and scratch resistance by adjusting the martens hardness of the hard coating layer within the above range, and by including the polyimide-based substrate and the hard coating layer together, the elongation of the hard coating film is reduced By adjusting within the above range, bending resistance is also improved, so that it is advantageously applied to a flexible image display device.

polyimide base material

The hard coating film according to an embodiment of the present invention includes a polyimide-based substrate having a glass transition temperature of 230° C. or higher, and thus, when used with a hard coating layer satisfying the Martens hardness presented in the present invention, the elongation of the entire hard coating film It can be improved to 8% or more, and transparency is also excellent.

According to one embodiment of the present invention, the polyimide-based substrate is copolymerized with an amine-based compound including an aromatic ring and a fluorine element in a molecule and an anhydride, so that bending resistance can be further improved, and the characteristic yellow color of polyimide There is an advantage in that transparency can also be further improved by lowering the degree.

According to one embodiment of the present invention, the polyimide-based substrate may have a transmittance of 89% or more and a yellowness of 2.0 or less at a wavelength of 550 nm.

The amine-based compound including an aromatic ring and a fluorine element in the molecule may be used without particular limitation as long as it is used in the art, for example, it may be one or more of compounds selected from the group consisting of the following Chemical Formulas 1 to 6.

[Formula 1]

[Formula 2]

[Formula 3]

[Formula 4]

[Formula 5]

[Formula 6]

The anhydride may be used without particular limitation as long as it is used for preparing a polyimide-based substrate in the art, but the following Chemical Formulas 7 to At least one selected from the group consisting of compounds represented by 18 may be preferably used.

In particular, according to one embodiment of the present invention, the anhydride may include an aromatic ring and a fluorine element together, for example, may be a compound represented by Chemical Formula 7, in which case transparency and glass transition temperature may be further improved. there is an advantage

[Formula 7]

[Formula 8]

[Formula 9]

[Formula 10]

[Formula 11]

[Formula 12]

[Formula 13]

[Formula 14]

[Formula 15]

[Formula 16]

[Formula 17]

[Formula 18]

hard coating layer

The hard coating film according to an embodiment of the present invention includes a hard coating layer on at least one surface of the above-described substrate, and ^{by adjusting the Martens hardness of the hard coating layer to 150 to 250N/mm 2} , pencil hardness and scratch resistance are excellent and , When used with the above-described polyimide-based substrate, it is possible to control the elongation of the hard coating film to 8% or more, and if it is less than the Martens hardness range, pencil hardness and scratch resistance may be reduced, and exceeding the above range In this case, the hardness of the entire hard coating film may be reduced despite being used together with the polyimide-based substrate of the present invention due to high hardness.

According to one embodiment of the present invention, the hard coating layer may include a cured product of the hard coating composition, the hard coating composition is a light-transmitting resin (A), a photoinitiator (B), a solvent (C) and an additive (D) It may be to include one or more selected from the group consisting of.

light transmittance Resin (A)

According to an embodiment of the present invention, the light-transmitting resin (A) may mean a photo-curable resin, and the photo-curable resin may include a photo-curable (meth)acrylate oligomer or monomer.

As the photocurable (meth)acrylate oligomer, epoxy (meth)acrylate, urethane (meth)acrylate, etc. are commonly used, and urethane (meth)acrylate may be more preferable. Urethane (meth)acrylate can be prepared in the presence of a catalyst in the presence of a compound having a polyfunctional (meth)acrylate and an isocyanate group having a hydroxyl group in the molecule. Specific examples of the (meth)acrylate having a hydroxyl group in the molecule include 2-hydroxyethyl (meth)acrylate, 2-hydroxyisopropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, capro At least one selected from the group consisting of lactone ring-opened hydroxyacrylate, a pentaerythritol tri/tetra (meth) acrylate mixture, and a dipentaerythritol penta/hexa (meth) acrylate mixture may be selected. In addition, specific examples of the compound having an isocyanate group include 1,4-diisocyanatobutane, 1,6-diisocyanatohexane, 1,8-diisocyanatooctane, 1,12-diisocyanatododecane, 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, tetramethylxylene-1, 3-diisocyanate, 1-chloromethyl-2,4-diisocyanate, 4,4'-methylenebis(2,6-dimethylphenylisocyanate), 4,4'-oxybis(phenylisocyanate), hexamethylenediisocyanate At least one selected from the group consisting of trifunctional isocyanate derived from, and trimethanol adduct toluene diisocyanate.

The monomer is a commonly used photocurable functional group having an unsaturated group such as a (meth)acryloyl group, a vinyl group, a styryl group, and an allyl group in a molecule, and among them, a (meth)acryloyl group is more preferable.

The monomer having the (meth) acryloyl group is specifically exemplified by neopentyl glycol acrylate, 1,6-hexanediol (meth) acrylate, propylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, Dipropylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, trimethylolethane tri(meth)acrylate, 1 ,2,4-cyclohexanetetra(meth)acrylate, pentaglycerol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, pentaerythritol tri(meth)acrylate, ethoxylated pentaerythritol triacrylate , dipentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, ethoxylated dipentaerythritol hexaacrylic rate, Tripentaerythritol tri (meth) acrylate, tripentaerythritol hexatri (meth) acrylate, bis (2-hydroxyethyl) isocyanurate di (meth) acrylate, hydroxyethyl (meth) acrylate, hydride Roxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, isooctyl (meth) acrylate, iso-dexyl (meth) acrylate, stearyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylic One or more types may be selected from the group consisting of late, phenoxyethyl (meth) acrylate, and isoborneol (meth) acrylate.

The above-mentioned photocurable (meth)acrylate oligomer or monomer may be used alone or in combination of two or more.

According to an embodiment of the present invention, the light-transmitting resin (A) may include the resin (A-1) in which the molar mass (g/mol) divided by the number of functional groups is 100 to 500. At this time, the light-transmitting resin (A) is a resin other than the resin (A-1) (A-2), that is, a resin (A-2) in which the molar mass divided by the number of functional groups is out of the range of 100 to 500; and the resin (A-1); may be included together.

As the number of functional groups of the light-transmitting resin increases, the number of cross-linking points that can be cross-linked increases when the number of functional groups increases, and durability such as hardness and scratch resistance can be improved. As the number of functional groups of the light-transmitting resin decreases, the elongation may be improved, thereby improving flex resistance, but when photopolymerized, the number of cross-linking points that can be cross-linked decreases, so durability such as hardness and scratch resistance may also be reduced.

Therefore, when the light-transmitting resin (A) of the present invention includes the resin (A-1) that satisfies the above-mentioned conditions, the Martens hardness of the hard coating layer prepared using the same and the elongation of the hard coating film are required in the present invention. There is an advantage that it is possible to adjust the range, which has the advantage that it is possible to manufacture a hard coating film excellent in pencil hardness, scratch resistance, elongation and bending resistance.

In addition, according to an embodiment of the present invention, the content of the resin (A-1) in which the value obtained by dividing the molar mass by the number of functional groups is 100 to 500 is 40 parts by weight based on 100 parts by weight of the total solid content in the hard coating composition including the same to 80 parts by weight, and when the content of the resin (A-1) is included within the above range, the Martens hardness of the hard coating layer prepared with the hard coating composition including the same and the elongation of the hard coating film are within the scope of the present invention. By adjusting the inside, there is an advantage in that it is possible to prepare a hard coating film having excellent pencil hardness, scratch resistance, elongation and bending resistance.

According to an embodiment of the present invention, the content of the light-transmitting resin (A) may be included in an amount of 1 to 80 parts by weight based on 100 parts by weight of the total hard coating composition including the same. When the content of the light-transmitting resin (A) is included in the above range, there is an advantage that can prevent the occurrence of curl (curl) of the hard coating layer manufactured using the same.

photoinitiator (B)

In the present invention, the photoinitiator (B) is not particularly limited, and may be used without limitation as long as it is used in the art. Specifically, one or more selected from the group consisting of hydroxy ketones, amino ketones, hydrogen recycler photoinitiators, and combinations thereof may be used, and more specifically, 2-methyl-1-[4-(methylthio)phenyl ]2-morpholinepropanone-1, diphenylketone, benzyldimethylketal, 2-hydroxy-2-methyl-1-phenyl-1-one, 4-hydroxycyclophenylketone, 2,2-dimethoxy- 2-phenyl-acetophenone, anthraquinone, fluorene, triphenylamine, carbazole, 3-methylacetophenone, 4-chnoloacetophenone, 4,4-dimethoxyacetophenone, 4,4-diaminobenzophenone , 1-hydroxycyclohexylphenyl ketone, benzophenone, diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide and at least one selected from the group consisting of a combination thereof may be used, but is limited thereto no.

The content of the photoinitiator (B) is not particularly limited in the present invention, but may be included in an amount of 0.1 to 10 parts by weight, specifically 1 to 5 parts by weight, based on 100 parts by weight of the total hard coating composition including the same. When the content of the photoinitiator (B) is included within the above range, even if the curing rate of the hard coating composition is shortened, the occurrence probability of non-curing is reduced, thereby preventing deterioration of mechanical properties and suppressing the occurrence of cracks. there is an advantage

Solvent (C)

In the present invention, the solvent (C) is not particularly limited, and any solvent used in the art may be used without any particular limitation. Specifically, alcohol (methanol, ethanol, isopropanol, butanol, methyl cellulose, ethyl solvorb, etc.), ketone (methyl ethyl ketone, methyl butyl ketone, methyl isobutyl ketone, diethyl ketone, dipropyl ketone, cyclo hexanone), hexane (hexane, heptane, octane, etc.), benzene-based (benzene, toluene, xylene, etc.), but is not limited thereto.

The content of the solvent (C) is not particularly limited in the present invention, but may be included in an amount of 10 to 95 parts by weight based on 100 parts by weight of the total composition for forming a hard coating layer including the same. When the solvent (C) is included within the above range, it is possible to improve workability by appropriately adjusting the viscosity, and there is an advantage that can shorten the curing time.

Additive (D)

The additive (D) is not particularly limited in the present invention, but may include, for example, inorganic oxide fine particles, a leveling agent, and the like.

The inorganic oxide fine particles are uniformly formed in the coating film to improve mechanical properties such as abrasion resistance, scratch resistance, and pencil hardness.

The inorganic oxide fine particles may have a particle size of 100 nm or less, and in this case, it is possible to prevent aggregation in the composition to form a uniform coating film, thereby preventing deterioration of mechanical properties.

The inorganic oxide fine particles may include, for example, silicon oxide (silica), titanium oxide, aluminum oxide, zinc oxide, tin oxide, zirconium oxide, and the like, but is not limited thereto.

The leveling agent may include, but is not limited to, a silicone-based leveling agent, a fluorine-based leveling agent, and an acrylic-based leveling agent. When the leveling agent is included together as described above, there is an advantage that smoothness and coatability can be imparted when forming a coating film.

The hard coating film according to an aspect of the present invention includes a hard coating layer on at least one surface of a substrate, and the substrate is a polyimide-based substrate having a glass transition temperature (Tg) of 230° C. or higher, and the Martens hardness of the hard coating layer is 150 to 250N/mm ² , and the elongation of the hard coating film is characterized in that it is 8% or more, and more specifically, the elongation may be 8 to 20%. As such, the hard coating film of the present invention has the advantage of excellent pencil hardness and scratch resistance by adjusting the martens hardness of the hard coating layer within the above range, and by including the polyimide-based substrate and the hard coating layer together, the elongation of the hard coating film is reduced By adjusting within the above range, bending resistance is also improved, so that it is advantageously applied to a flexible image display device.

< window >

Another aspect of the present invention is a window provided with the above-described hard coating film.

The window is not particularly limited, but specifically a display such as LCD, OLED, LED, FED, various mobile communication terminals using the same, a touch panel of a smart phone or tablet PC, or a use or functionality to replace a cover glass such as electronic paper It can be used as a layer.

The window has an advantage of being flexible by having the hard coating film of the present invention having an elongation of 8% or more.

< window laminate >

Another aspect of the present invention is a window laminate including the above-described window, specifically, at least one selected from the group consisting of a polarizing layer and a touch sensor layer on at least one surface of the window provided with the hard coating film of the present invention. It relates to a window laminate further comprising. In addition, if necessary, the window may include a polarizing layer or a touch sensor layer having a protective film disposed therebetween with an adhesive layer therebetween.

In addition, a colored non-display area or a bezel part printed to surround the edge of the window may be provided on one surface of the window, and the non-display area or the bezel part may be made of a metal layer or an organic material layer, and may be in the form of a single layer or a multi-layer, respectively. have. In addition, a polarizing layer may be bonded to one surface of the window directly or with an adhesive layer interposed therebetween. For example, the polarizing layer may extend continuously over the non-display area or the bezel portion, and a conventional polarizing plate including a polyvinyl alcohol-based polarizer and a protective film attached to at least one surface of the polyvinyl alcohol-based polarizer. can be Another example of the polarizing layer may include a liquid crystal layer including a liquid crystal compound, and may further include an alignment layer for imparting alignment to the liquid crystal layer.

At least one retardation film may be formed on the polarizing layer, and a touch sensor layer may be disposed on the polarizing layer directly or with the retardation film interposed therebetween. The touch sensor layer may be formed by forming different electrode layers on at least one surface of the base film, and when formed on one surface, a separate insulating layer may be disposed between the different electrode layers.

<Image display device>

Another aspect of the present invention relates to an image display device including the above-described window as an image display device, the image display device including the window laminate provided with the hard coating film of the present invention.

The image display device is not particularly limited, but for example, a liquid crystal display device (LCD), a field emission display device (FED), a plasma display device (PDP), an organic light emitting device (OLED), a flexible display device, etc. can

In particular, the hard coating film of the present invention has excellent bending resistance by adjusting the elongation to 8% or more, and thus has a more advantageous advantage when applied to a flexible image display device.

Hereinafter, preferred examples are presented to help the understanding of the present invention, but the following examples are only illustrative of the present invention, and it will be apparent to those skilled in the art that various changes and modifications are possible within the scope and spirit of the present invention. , it is natural that such variations and modifications fall within the scope of the appended claims. In the following Examples and Comparative Examples, "%" and "part" indicating the content are by weight unless otherwise specified.

manufacturing example One: hard coating Preparation of the composition

manufacturing example 1-1.

40 parts by weight 6-functional urethane acrylate (Miwon Specialty Chemical, MIRAMER 620D, molar mass/functional group = 383), 10 parts by weight polyfunctional acrylate (Miwon Specialty Chemical, MIRAMER SP1106, molar mass/functional group = 543), 47 parts by weight Methyl ethyl ketone, 2.7 parts by weight 1-hydroxycyclohexylphenyl ketone, and 0.3 parts by weight silicone-based additive (BYK, BYK-UV3570) were mixed using a stirrer and filtered using a PP filter to prepare a hard coating composition did.

manufacturing example 1-2.

30 parts by weight 6-functional urethane acrylate (Miwon Specialty Chemical, MIRAMER 620D, molar mass/functional group = 383), 20 parts by weight polyfunctional acrylate (Miwon Specialty Chemical, MIRAMER SP1106, molar mass/functional group = 543), 47 parts by weight Methyl ethyl ketone, 2.7 parts by weight 1-hydroxycyclohexylphenyl ketone, and 0.3 parts by weight silicone-based additive (BYK, BYK-UV3570) were mixed using a stirrer and filtered using a PP filter to prepare a hard coating composition did.

manufacturing example 1-3.

20 parts by weight 6-functional urethane acrylate (Miwon Specialty Chemical, MIRAMER 620D, molar mass/functional group = 383), 30 parts by weight polyfunctional acrylate (Miwon Specialty Chemical, MIRAMER SP1106, molar mass/functional group = 543), 47 parts by weight Methyl ethyl ketone, 2.7 parts by weight 1-hydroxycyclohexylphenyl ketone, and 0.3 parts by weight silicone-based additive (BYK, BYK-UV3570) were mixed using a stirrer and filtered using a PP filter to prepare a hard coating composition did.

manufacturing example 1-4.

30 parts by weight 6-functional urethane acrylate (Miwon Specialty Chemicals, MIRAMER 620D, molar mass/functional group = 383), 20 parts by weight ethoxylated dipentaerythritol hexaacrylate (molar mass/functional group = 147), 47 parts by weight methyl Ethyl ketone, 2.7 parts by weight 1-hydroxycyclohexylphenyl ketone, and 0.3 parts by weight silicone-based additive (BYK, BYK-UV3570) were blended using a stirrer and filtered using a PP filter to prepare a hard coating composition. .

manufacturing example 1-5.

30 parts by weight 6-functional urethane acrylate (Miwon Specialty Chemicals, MIRAMER 620D, molar mass/functional group = 383), 20 parts by weight ethoxylated pentaerythritol triacrylate (molar mass/functional group = 147), 47 parts by weight methylethyl A ketone, 2.7 parts by weight 1-hydroxycyclohexylphenyl ketone, and 0.3 parts by weight of a silicone-based additive (BYK, BYK-UV3570) were blended using a stirrer and filtered using a PP filter to prepare a hard coating composition.

manufacturing example 1-6.

50 parts by weight of polyfunctional acrylate (Miwon Specialty Chemical, MIRAMER SP1106, molar mass/functional group = 543), 47 parts by weight of methyl ethyl ketone, 2.7 parts by weight of 1-hydroxycyclohexylphenyl ketone, 0.3 parts by weight of a silicone additive (BYK Corporation) , BYK-UV3570) was blended using a stirrer and filtered using a PP material filter to prepare a hard coating composition.

manufacturing example 1-7.

20 parts by weight pentaerythritol triacrylate, 30 parts by weight 20 nano silica sol (solid content 40%, methyl ethyl ketone dispersed sol), 47 parts by weight methyl ethyl ketone, 2.7 parts by weight 1-hydroxycyclohexyl phenyl ketone, 0.3 parts by weight A silicone-based additive (BYK, BYK-UV3570) was blended using a stirrer and filtered using a PP filter to prepare a hard coating composition.

manufacturing example 2: Preparation of polyimide substrate

manufacturing example 2-1: embodiment Preparation of polyimide substrates

2,2'-Bis-(3,4-Dicarboxyphenyl)hexafluoropropanedianhydride (6-FDA) and 2,2'-Bis(trifluoromethyl)benzidine (TFMB) were added in a 1:1 molar ratio and synthesized under dimethylacetamide (DMAc) solvent. A polyamic acid was prepared. The prepared polyamic acid was coated on a SUS plate so that the final thickness of the film was 80 μm, and then baked at a temperature of 300° C. under nitrogen purge to prepare a polyimide substrate.

manufacturing example 2-2: comparative example Preparation of polyimide substrates

A polyimide substrate was prepared in the same configuration and method except that m-xylylenediamine (m-XDA) was used instead of TFMB in Preparation Example 2-1.

Experimental example 1. Measurement of transmittance, yellowness and glass transition temperature of polyimide-based substrates

The transmittance, yellowness, and glass transition temperature of each polyimide-based substrate prepared in Preparation Example 2 were measured, and the results are shown in Table 1 below.

At this time, the transmittance was measured using a colorimeter (OSP-200, manufactured by Olympus), and the yellow index (YI) was evaluated using CM-3600d (Konica) equipment. In the yellowness evaluation, the measurement light source was D65, the viewing angle was 2°, and the measurement area was set to D1925 mode.

The glass transition temperature was measured using a differential scanning calorimeter.

Preparation 1-1 Preparation 1-2 Transmittance (550nm, %) 90.3 89.5 Yellowness (YI) 1.75 1.9 Glass transition temperature (Tg, ℃) 272 197

Referring to Table 1, in the case of the polyimide substrate satisfying the configuration of the present invention (Preparation Example 1-1), the transmittance is superior to that of the polyimide substrate (Preparation Example 1-2) that does not satisfy the configuration of the present invention. , it can be confirmed that the transparency is more excellent because the yellowness is low, and the glass transition temperature is high, and it can be confirmed that the flexible effect is also excellent.

Example and comparative example : hard coating manufacture of film

Example One.

After curing the hard coating composition of Preparation Example 1-1 on the polyimide substrate (PI, 80 μm) of Preparation Example 2-1, the coating was applied to a thickness of 10 μm, followed by solvent drying and UV accumulated light amount of 500 J/cm ² A hard coating film was prepared by irradiation.

Example 2.

A hard coating film was prepared in the same configuration and method as in Example 1 except that the hard coating composition of Preparation Example 1-2 was used instead of the hard coating composition of Preparation Example 1-1 in Example 1.

Example 3.

A hard coating film was prepared in the same configuration and method as in Example 1 except that the hard coating composition of Preparation Example 1-3 was used instead of the hard coating composition of Preparation Example 1-1 in Example 1.

Example 4.

A hard coating film was prepared in the same configuration and method as in Example 1 except that the hard coating composition of Preparation Example 1-4 was used instead of the hard coating composition of Preparation Example 1-1 in Example 1.

Example 5.

A hard coating film was prepared in the same configuration and method as in Example 1, except that the hard coating composition of Preparation Example 1-5 was used instead of the hard coating composition of Preparation Example 1-1 in Example 1.

comparative example One.

A hard coating film was prepared in the same configuration and method as in Example 1 except that the hard coating composition of Preparation Example 1-6 was used instead of the hard coating composition of Preparation Example 1-1 in Example 1.

comparative example 2.

A hard coating film was prepared in the same configuration and method as in Example 1 except that the hard coating composition of Preparation Example 1-7 was used instead of the hard coating composition of Preparation Example 1-1 in Example 1.

comparative example 3.

A hard coating film was prepared in the same configuration and method as in Example 1, except that in Example 1, a polymethyl methacrylate (PMMA) base having a thickness of 60 μm was used instead of a polyimide-based base material.

comparative example 4.

A hard coating film was prepared in the same configuration and method as in Example 1 except that in Example 1, a triacetyl cellulose (TAC) substrate having a thickness of 80 μm was used instead of a polyimide-based substrate.

comparative example 5.

A hard coating film was prepared in the same configuration and method as in Example 1, except that in Example 1, a cycloolefin polymer (COP) having a thickness of 80 μm was used instead of the polyimide-based substrate.

comparative example 6.

A hard coating film was prepared in the same configuration and method as in Example 1, except that the polyimide-based substrate of 2-2 was used instead of the polyimide-based substrate of Preparation Example 2-1 as the substrate in Example 1.

Experimental example 2. martens hardness measurement

After bonding the base film to the glass using a transparent adhesive so that the hard coating layer side of the hard coating film prepared in Examples 1 to 5 and Comparative Examples 1 to 6 goes upward, using a nanoindenter (Fischer) The surface hardness of the hard coating layer was measured with a small load of 1 mN, and the results are shown in Table 2 below.

Experimental example 3. elongation measurement

After cutting the hard coating film prepared in Examples 1 to 5 and Comparative Examples 1 to 6 to a size of 10 cm × 5 mm, when measuring the SS curve using UTM (Instron), the elongation at the point where the film is lowered is measured Therefore, the results are shown in Table 2 below.

Experimental example 4. Pencil hardness measurement

After fixing both ends of the base film with a tape on the glass so that the hard coating layer side of the hard coating film prepared in Examples 1 to 5 and Comparative Examples 1 to 6 goes upward, a pencil hardness tester (Seokbo Science Co., Ltd.) was used. Thus, the pencil hardness was measured with a load of 1 kg. The hardness at which scratches did not occur more than 4 times after evaluation with the same pencil 5 times was referred to as the pencil hardness, and the results are shown in Table 2 below.

Experimental example 5. scratch resistance Experiment

After bonding the base film to the glass using a transparent adhesive so that the hard coating layer side of the hard coating film prepared in Examples 1 to 5 and Comparative Examples 1 to 6 goes upward, 500 g / using steel wool (#0000) With ^{a load of cm 2,} the presence or absence of scratches by reciprocating friction 10 times was transmitted and reflected by a three-wavelength lamp and observed with the naked eye. At this time, scratch resistance was evaluated according to the following evaluation criteria, and the results are shown in Table 2 below.

<Evaluation criteria>

○: Recognized as less than 10 scratches

×: recognized as more than 10 scratches

Experimental example 6. Flexural Resistance Test

The film was repeatedly folded and unfolded 10,000 times with a radius of curvature of 1 mm so that the hard coating layer side of the hard coating film prepared in Examples 1 to 5 and Comparative Examples 1 to 6 was folded outward. was observed, and evaluated by the following evaluation criteria, and the results are shown in Table 2 below.

<Evaluation criteria>

○: No breakage

×: occurrence of breakage

Martens hardness (N/mm ² ) Elongation (%) pencil hardness scratch resistance Flexibility Example 1 232 9.4% 3H ○○ ○○ Example 2 215 10.8% 3H ○○ ○○ Example 3 183 14.2% 3H ○○ ○○ Example 4 202 11.5% 3H ○○ ○○ Example 5 190 13.5% 3H ○○ ○○ Comparative Example 1 132 15.6% 2H ×× ○○ Comparative Example 2 324 4.3% 4H ○○ ×× Comparative Example 3 219 4.2% 3H ○○ ×× Comparative Example 4 208 6.5% 3H ○○ ×× Comparative Example 5 205 3.8% 3H ○○ ×× Comparative Example 6 220 5.3% 3H ○○ ××

Referring to Table 2, Examples 1 to satisfying the Martens hardness of the hard coating layer presented in the present invention, and satisfying the elongation range of the hard coating film of the present invention by including the polyimide-based substrate presented in the present invention In the case of 5, it was confirmed that all of the pencil hardness, scratch resistance and bending resistance were superior to those of Comparative Examples 1 to 6, which did not satisfy any one of the configurations of the present invention.

Specifically, in the case of the hard coating film of Comparative Example 1 including a hard coating layer outside the range of the Martens hardness presented in the present invention, it was confirmed that the pencil hardness and scratch resistance were not good, and the Martens hardness presented in the present invention was In the case of Comparative Example 2, which exceeds the pencil hardness and scratch resistance, it was confirmed that, by not including the polyimide-based substrate presented in the present invention, the elongation did not satisfy the range of the present invention and the bending resistance was poor. . In addition, in the case of Comparative Examples 3 to 6 using a substrate other than the polyimide-based substrate presented in the present invention, it was confirmed that the elongation range did not satisfy the range of the present invention and thus the bending resistance was not good, and in particular, the glass transition temperature was In the case of Comparative Example 6 using a polyimide-based substrate that does not satisfy the scope of the present invention, it was confirmed that the flexible image display device was not easily applied due to poor bending resistance.

Claims (14)

In the hard coating film comprising a hard coating layer on at least one surface of the substrate,
The substrate is a polyimide-based substrate having a glass transition temperature (Tg) of 230° C. or higher,
Martens hardness of the hard coating layer is 150 to 250N / mm ² ,
The elongation of the hard coating film is 8% to 20%,
A hard coating film, characterized in that when repeatedly bent 10,000 times with a radius of curvature of 1 mm in a state composed of the polyimide-based substrate and the hard coating layer, breakage does not occur. According to claim 1,
The polyimide-based substrate is a copolymer of an amine-based compound and an anhydride, and the amine-based compound and the anhydride include an aromatic ring and a fluorine element, respectively. According to claim 1,
The polyimide-based substrate has a transmittance of 89% or more at a wavelength of 550 nm. According to claim 1,
The polyimide-based substrate is a hard coating film, characterized in that the yellowness (Yellow Index) is 2.0 or less. According to claim 1,
The hard coating layer is a hard coating film, characterized in that it comprises a cured product of the hard coating composition. 6. The method of claim 5,
The hard coating composition is a hard coating film, characterized in that it comprises at least one selected from the group consisting of a light-transmitting resin (A), a photoinitiator (B) and a solvent (C). 7. The method of claim 6,
The light-transmitting resin (A) is a hard coating film, characterized in that it comprises a resin (A-1) in which the molar mass divided by the number of functional groups is 100 to 500. 8. The method of claim 7,
The resin (A-1) is a hard coating film, characterized in that it is included in 40 to 80 parts by weight based on 100 parts by weight of the total solid content of the hard coating composition comprising the same. 7. The method of claim 6,
The light-transmitting resin (A) is a hard coating film, characterized in that it is included in an amount of 1 to 80 parts by weight based on 100 parts by weight of the total hard coating composition including the same. A window of an image display device provided with the hard coating film of any one of claims 1 to 9. A window laminate comprising the window of claim 10 . 12. The method of claim 11,
Window laminate, characterized in that it further comprises one or more selected from the group consisting of a polarizing layer and a touch sensor layer on at least one surface of the window. An image display device comprising the window laminate of claim 11 . 14. The method of claim 13,
The image display device is an image display device, characterized in that the flexible image display device.