KR20160103681A - Foldable hard coating film and display device comprising thereof - Google Patents

Abstract

The present invention relates to a foldable hard coating film and a display device comprising the same and, more specifically, to a foldable hard coating film which is applied as a glass replacement or a high hardness film of a foldable display by simultaneously satisfying hardness and folding properties when using a display because of not generating a crack in the case of folding a film by reducing the thickness of a folding part; and to a display device comprising the same.

Description

[0001] The present invention relates to a foldable hard coating film and a display comprising the same,

The present invention relates to a foldable hard coat film having a hardness and scratch resistance, which can be folded without cracks, and a display having the same.

In the near future, mobile devices that can bend or fold beyond simple curved and fixed curved smartphones are expected to emerge in the market soon.

This is a product that adopts a flexible display format that is one step further than the currently commercialized curved display. Flexible display technology has evolved from folded curved to bentable bendable, foldable foldable, and finally rolled into rollable or size It is expected to evolve into a stretchable form that can be increased or decreased.

When the display is designed to be foldable, it can be used as a tablet when it is folded, and it can be used as a smartphone if it is folded. It can be used as a single product of different size. Devices can be doubled if they can be folded and carried.

Foldable display is a display that can be folded in half like a book or notebook, and various companies have proposed various technologies and patents.

Recently, Japanese Semiconductor Energy Laboratory (SEL), Advanced Film Device (AFD), and Nokia have proposed an OLED foldable display that can be folded in half or three times.

In addition, Apple has filed a three-sided wraparound display using a bent and wrapping AMOLED (U.S. Patent Application Publication No. 2013-0076612), and recently, an elliptical hollow tube including a cylindrical cylinder shape (hollow in the middle), a triangular or rectangular cross- And has filed a patent application for a transparent display with an empty center.

In addition, LG Display and Samsung Electronics also propose a display in which various sides are bent or folded to form a polygonal shape (Korean Patent Laid-Open Publication No. 2014-0032773, No. 2014-0119585, US Patent Publication No. 2015-0022436).

Normally, in the case of a display, a cover window made of a glass material is provided at the outermost side to protect the display. However, in the case of glass, it is not applicable to a foldable display, and a hard hard coating film having high hardness and abrasion resistance to replace glass is used.

In order to ensure hardness of the glass level, it is necessary to increase the thickness of the hard coat layer in the hard coat film. As the thickness of the hard coat layer increases, the surface hardness can be increased. However, the hard coat layer is hardened and shrunk, Crack (or cracking) or peeling of the coating layer tends to occur, so that it is not easy to apply it practically.

For example, Korean Patent Laid-Open Publication No. 2008-55698 mentions that hardness can be increased while presenting a multi-layered hard-coating optical film, but no countermeasure against cracks is presented at all.

Particularly, when a hard hard coating film is applied to a foldable display, it is contracted by compression in the folded inner region and stretched due to the tension on the outer side, resulting in a more serious crack in the folded region.

As a result, the production of a flexible hard coat film has been proposed. Korean Patent Laid-Open Publication No. 2014-0104175 proposes that a flexible hard coat film can be prepared by polymerizing an oligosiloxane containing an alicyclic epoxy group. This film can be applied to a curved display or the like by securing a certain degree of flexibility, but the degree of flexibility is insufficient for a folder-type display.

KOKAI Publication No. 2014-0033546 discloses that the unfolded region has a higher PMMA ratio than PnBA among PMMA (poly methyl methacrylate) and PnBA (PnBA) to have different hardnesses in the folded region and unfolded region And the cover window material, which includes the PMN and the PnBA ratio more than the PMMA, is presented.

Such a method can be said to prevent cracks in the folded region to some extent, but the materials in the folded region and the non-folded region are different from each other, and the manufacturing method thereof can be difficult.

Korean Patent Publication No. 2014-0033546

The present applicant has conducted various studies in order to produce a foldable hard hard coating film through a simple process using a conventional hard coating layer composition. As a result, it has been found that when the thickness of the hard coating layer in the folded region is controlled, , It can be manufactured without changing the material in the folded region and the non-folded region, and the obtained film has a high level of hardness and scratch resistance, and cracks do not occur even in a severe bending test.

Accordingly, it is an object of the present invention to provide a foldable hard coat film which is used as a hard hard coating film.

Another object of the present invention is to provide a use of the above-mentioned foldable hard coating film for a display.

In order to accomplish the above object, the present invention provides a foldable hard coating film on a base film on which a hard coating layer having a foldable portion and a non-folded portion are folded with respect to a folding line.

In this case, the folding line forms a straight line along the vertical or horizontal direction of the foldable hard coating film, and one or more folding lines are formed.

The folded portion of the hard coat layer is characterized by having a thickness ratio of 70% or less with respect to the vertical thickness of the unfolded portion.

The folded portion and the non-folded portion are connected by a gentle slope.

Such a foldable hard coat film is a high hardness hard coat film having a pencil hardness of 5H or more and is characterized by being applied to a foldable display.

The hard coating film according to the present invention is a high hardness, foldable hard coating film, which reduces the thickness at the folding portion, so that cracks do not occur when the film is folded, so that when the foldable display is used, high hardness, scratch resistance, .

1 is a cross-sectional view of a foldable hard coating film according to an embodiment of the present invention.
2 is a perspective view of a foldable hard coating film according to an embodiment of the present invention.
3 is a cross-sectional view of a hard coating layer according to an embodiment of the present invention.
4 is a perspective view showing folding of a foldable hard coating film according to an embodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail with reference to the drawings.

FIG. 1 is a sectional view of a foldable hard coating film according to an embodiment of the present invention, and FIG. 2 is a perspective view thereof.

Referring to Figs. 1 and 2, a hard coating film 10 includes a base film 1 and a hard coating layer 3 formed thereon.

The hard coating layer 3 is composed of a foldable portion 3a and a non-folded portion 3b that can be folded with respect to a folding line for folding (bending or folding) the foldable hard coating film 10.

At this time, a line A capable of being folded due to the folded portion 3a is realized. The line A is formed in a straight line in the vertical direction of the foldable hard coating film 10 as shown in FIG. The line A may be formed in the horizontal direction in addition to the vertical direction, and at least one or more of the lines A in the hard coat layer 3 may be formed. For example, the foldable hard coating film 10 can be folded once by the folded portion 3a formed along the line A in the vertical direction as shown in FIG. 2. When the foldable hard coating film 10 is formed by a plurality of folded portions, .

The folded portion 3a may be located at the center of the foldable hard coating film 10 as shown in FIG. For example, when the foldable hard coating film 10 has two folded portions 3a, folded portions 3a are located at three positions. The number and position of the folded portions 3a are not particularly limited in the present invention and can be varied depending on the field of application of the foldable hard coating film 10, so that there is no problem in practical use.

In particular, the foldable hard coating film 10 according to the present invention is a foldable film, which is capable of folding along a line by the folded portion 3a. In the case of the conventional hard coating film, cracks are generated at the time of folding several times. In the present invention, however, such problems can be originally prevented by making the thicknesses of the folded portions 3a and the unbended portions 3b different, have.

In other words, as shown in Figs. 1 and 2, in the present invention, the folded portion 3a should be formed to have a relatively thin thickness with respect to the non-folded portion 3b, Has a thickness ratio of 70% or less with respect to the vertical thickness of the folded portion 3b, and preferably has a thickness ratio of 50% or less. This can be expressed as: < EMI ID =

[Equation 1]

(In the above formula (1)

Ta is the average thickness of the folded portion 3a,

Tb is the average thickness of the unbended portion 3b)

Considering that the thickness of the non-folded portion 3b must satisfy a certain level or more in order to fulfill the role of the hard coat layer 3, the value of the folded portion 3a in the thickness ratio The lower the thickness of the folded portion 3a is, the more advantageous it is. If the thickness ratio exceeds the above range, the object of the present invention can not be achieved, but cracking may occur at the time of folding, so that it is preferable to adjust the thickness within the above range.

More specifically, when the normal thickness of the hard coat layer 3 is 10 to 200 占 퐉, the thickness of the unbended portion 3b is 10 to 200 占 퐉, and the thickness of the folded portion 3a is 0.05 to 140 占 퐉 have.

Particularly, even in this partial thickness adjustment, the folded portion 3a and the unfolded portion 3b maintain the same hard coating property as well as scratch resistance in the surface.

In addition, the folded portion 3a and the non-folded portion 3b of the hard coat layer 3 are preferably not visible due to the folded portion 3a when applied to a display or the like. In order to flexibly bend the folded portion 3a ) And the non-folded portion (3b) are connected by a gentle slope.

As a result, when the foldable hard coating film 10 is folded as shown in FIG. 4, the stress applied to the unbended portion 3b due to the folded portion 3a can be minimized.

The foldable hard coating film (10) according to the present invention is a hard hard coating film having a pencil hardness of 5H or more, 7H or more, or 9H or more under a load of 500g. The foldable hard coating film 10 has scratch resistance of 10 or less scratches when it is reciprocated 10 times by a load of 1 kg in a friction tester. In addition, the light transmittance may be 87.0% or more, or 90.0% or more, and the haze may be 2.0% or less, or 1.0% or less, or 0.5% or less.

In particular, due to the structure composed of the folded portion 3a and the non-folded portion 3b, cracks are not generated even under a bending test under a severe condition (a bending test of 200,000 times with a 5 mm mandrel).

As described above, the foldable hard coating film 10 includes the base film 1 and the hard coat layer 3, and their materials, thickness, and the like can satisfy the conditions as the hard hard coating film Either can be used.

The base film (1) can be any ordinary transparent base film, and is not particularly limited in the present invention.

Specifically, examples of the transparent substrate include cycloolefin-based derivatives having units of monomers including cycloolefins such as norbornene and polycyclic norbornene monomers, diacetylcellulose, triacetylcellulose, acetylcellulose butyrate, isobutylester cellulose, Polyvinyl alcohol, polyvinyl alcohol, polyvinyl alcohol, polyvinyl alcohol, polyvinyl alcohol, polyvinyl alcohol, polyvinyl alcohol, polyvinyl alcohol, polyvinyl alcohol, polyvinyl alcohol, polyvinylacetate, polyvinyl alcohol, Polyolefins such as polypropylene, polymethylpentene, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyvinyl acetal, polyether ketone, polyether ether ketone, polyethersulfone, polymethyl methacrylate, polyethylene terephthalate, polybutylene Terre De-rate, it is possible to use a polyethylene naphthalate, a polycarbonate, a polyurethane, may be used one selected from among epoxy, non-stretched uniaxially or biaxially stretched film. Of these, a polyimide film, a monoaxial or biaxially stretched polyester film preferably having excellent transparency and heat resistance, a cycloolefin-based derivative film excellent in transparency and heat resistance and capable of coping with the enlargement of the film, and a film having transparency and optical anisotropy A triacetylcellulose film can be suitably used.

The thickness of the base film 1 is not particularly limited, but may be 8 to 1000 탆, preferably 20 to 150 탆. If the thickness is less than the above range, the strength of the film is lowered and the workability is lowered. On the contrary, when the thickness is over the range, transparency is lowered or thickness is increased when the film is applied to a display.

The hard coat layer 3 is prepared by coating a composition for forming a hard coat layer and then curing it. The composition for forming the hard coat layer includes a light transmitting resin, an initiator, a solvent, and further additives.

The light transmitting resin is a photocurable (meth) acrylate oligomer.

The photocurable (meth) acrylate oligomer may be at least one selected from the group consisting of epoxy (meth) acrylate, urethane (meth) acrylate and polyester (meth) acrylate, (Meth) acrylate or a mixture of two kinds of polyester (meth) acrylates can be used.

The urethane (meth) acrylate can be prepared by reacting a compound having a polyfunctional (meth) acrylate having a hydroxyl group in the molecule and an isocyanate group in the presence of a catalyst according to a method known in the art.

Specific examples of the polyfunctional (meth) acrylate having a hydroxyl group in the molecule include 2-hydroxyethyl (meth) acrylate, 2-hydroxyisopropyl (meth) acrylate, 4-hydroxybutyl , A caprolactone ring-opening hydroxyacrylate, a mixture of pentaerythritol tri / tetra (meth) acrylate, and a mixture of dipentaerythritol penta / hexa (meth) acrylate.

Specific examples of the compound having an isocyanate group include 1,4-diisocyanatobutane, 1,6-diisocyanatohexane, 1,8-diisocyanatooctane, 1,12-diisocyanatododecane, Diisocyanato-2-methylpentane, trimethyl-1,6-diisocyanatohexane, 1,3-bis (isocyanatomethyl) cyclohexane, trans-1,4-cyclohexane diisocyanate, Diisocyanate, toluene-2,6-diisocyanate, xylene-1,4-diisocyanate, tetramethyl xylene-1, Diisocyanate, 1-chloromethyl-2,4-diisocyanate, 4,4'-methylenebis (2,6-dimethylphenyl isocyanate), 4,4'-oxybis (phenylisocyanate), hexamethylene diisocyanate , And trifunctional isocyanate derived from trimethane propanol adduct toluene diisocyanate And at least one selected from the group consisting of halides.

The polyester (meth) acrylate can be prepared by reacting a polyester polyol and acrylic acid according to methods known in the art.

The polyester (meth) acrylate may be, for example, a polyester acrylate, a polyester diacrylate, a polyester tetraacrylate, a polyester hexaacrylate, a polyester pentaerythritol triacrylate, a polyester pentaerythritol tetraacryl And polyester pentaerythritol hexaacrylate, but is not limited to these.

The coating composition for forming the hard coat layer according to an embodiment of the present invention can be used including a photocurable monomer.

Examples of the monomer include a monomer having an unsaturated group such as a (meth) acryloyl group, a vinyl group, a styryl group or an allyl group in the molecule as a photocurable functional group, A monomer having an acryloyl group can be used.

 Examples of the monomer having a (meth) acryloyl group include neopentyl glycol acrylate, 1,6-hexanediol (meth) acrylate, propylene glycol di (meth) acrylate, triethylene glycol di Acrylate, trimethylolpropane tri (meth) acrylate, trimethylol ethane tri (meth) acrylate, triethylene glycol di (meth) acrylate, dipropylene glycol di (Meth) acrylate, pentaerythritol tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol tri (meth) acrylate, Acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate (Meth) acrylate, tripentaerythritol hexa (meth) acrylate, bis (2-hydroxyethyl) isocyanurate di (meth) acrylate, hydroxyethyl (Meth) acrylate, stearyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, isobutyl (meth) acrylate, , Phenoxyethyl (meth) acrylate, and isobonol (meth) acrylate, but are not limited thereto.

In particular, the use of the photocurable monomer in the content of the (meth) acrylate in the mixture with the tetrafunctional polyester (meth) acrylate can be used to increase the workability and compatibility of the photocurable coating composition , And an equal level of characteristics can be obtained.

The light-curable (meth) acrylate oligomer and the monomers, which are the above-mentioned light-transmitting resins, may be used singly or in combination of two or more thereof.

Such a translucent resin affects the quality of the coating film and is used in the range of 1 to 80% by weight, preferably 5 to 50% by weight, within 100% by weight of the total coating composition for hard coat layer formation. If the content is less than the above range, it is difficult to form a hard coat layer having a sufficient hardness even if it is difficult to form a coating film. If the content of the hard coat layer exceeds the above range, shrinkage after curing of the hard coat layer So that it is properly adjusted within the above range.

The photoinitiator can be used without limitation as long as it is used in the technical field. Specifically, the photoinitiator may be at least one selected from the group consisting of hydroxy ketones, aminoketones, and an aromatic cyclic photoinitiator.

Examples of the photoinitiator include 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropanone-1, diphenyl ketone, benzyldimethyl ketal, 2- 4-hydroxycyclophenyl ketone, 2,2-dimethoxy-2-phenyl-acetophenone, anthraquinone, fluorene, triphenylamine, carbazole, 3-methylacetophenone, 4 4-diaminobenzophenone, 1-hydroxycyclohexyl phenyl ketone, benzophenone, and diphenyl (2,4,6-trimethylbenzoyl) phosphine And at least one selected from the group consisting of titanium oxide and titanium oxide.

The content of the photoinitiator is in the range of 0.1 to 10% by weight, preferably 1 to 5% by weight, based on 100% by weight of the coating composition for forming the hard coat layer of the present invention. If the content is less than the above range, the curing speed of the composition is slow and uncured and mechanical properties are deteriorated. On the contrary, when the content exceeds the above range, cracking may occur in the coating due to overcuring.

The solvent is not limited and can be used as long as it is known as a solvent for a coating layer forming composition in the technical field.

Examples of usable solvents include alcohols (methanol, ethanol, isopropanol, butanol, methylcellulose, ethylsulosorb, etc.), ketones (methyl ethyl ketone, methyl butyl ketone, methyl isobutyl ketone, diethyl ketone, Cyclohexanone and the like), an acetate type (ethyl acetate, propyl acetate, n-butyl acetate, tertiary butyl acetate, methyl cellosolve acetate, ethyl cellosolve acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, Hexane, heptane, and octane), benzene (benzene, toluene, xylene and the like), ether (diethylene glycol dimethyl ether (meth) acrylate, , Diethylene glycol diethyl ether, diethylene glycol dipropyl ether, diethylene glycol dibutyl ether, propyl Such as glycol monomethyl ether and the like) can be preferably used. The solvents exemplified above may be used alone or in combination of two or more.

The content of the solvent is 10 to 95% by weight within 100% by weight of the entire composition for forming a hard coat layer. If the content of the solvent is less than the above range, the viscosity of the composition tends to be high, resulting in deterioration in workability. On the other hand, if the content of the solvent exceeds the above range, the drying process takes a long time and the economical efficiency is low. .

In addition to the above-mentioned components, the composition for forming a hard coat layer may further include components commonly used in the art such as antireflective agents, fillers, antioxidants, UV absorbers, light stabilizers, thermal polymerization inhibitors, , A surfactant, an antioxidant lubricant, an antifouling agent, and the like.

For example, in the examples of the present invention, nano silica sol as a filler and BYK Chemicals as a leveling agent were used, and selection and content control of each additive can be appropriately selected by those skilled in the art Do.

The foldable hard coating film according to one embodiment of the present invention

(S1) a step of applying a composition for forming a hard coating layer on a base film, wherein the hard coating layer is applied with different thicknesses of folded portions and unfolded portions,

S2), < / RTI > and

S3) curing the dried coating to form a hard coating layer, which will be described in detail below.

First, in S1), a composition for forming a hard coat layer is applied on a base film.

The coating can be performed by a conventional coating method. For example, a coating process can be performed using a suitable method such as die coater, air knife, reverse roll, spray, blade, casting, gravure, microgravure or spin coating.

Coating is performed in consideration of the thickness of the hard coat layer after the final curing. At this time, the hard coating layer according to the present invention is composed of folded portions having different thicknesses and non-folded portions, and the coating process is controlled so that they can be connected to each other at a gentle slope.

For example, the embodiment of the present invention is divided into two unfolded regions and one folded region, and three stages of unfolded region coating -> folded region coating -> unfolded region coating, The thicknesses of the folded part and the non-folded part were differently coated.

As another example, it is possible to use an apparatus equipped with a nozzle having a different discharge amount so as to coat different thicknesses. That is, the area of the unbended area and the area of the folded part were selected, and the amount of the applied coating composition was controlled to be coated in a batch, thereby coating the folded part and the unbended part with different thicknesses.

One or more folding lines may be formed, and in order to form a plurality of folding lines, the thickness of the coating of the composition may be repeatedly adjusted to fit the folded portion and the non-folded portion in this step.

Next, the coating film coated in S1) is dried.

The drying is not particularly limited in the present invention, and a normal drying step can be performed. The volatiles are preferably evaporated at a temperature of 30 to 150 DEG C for 10 seconds to 2 hours, more preferably 30 seconds to 1 hour. Through such drying, the folded portion and the non-folded portion are connected to each other at a gentle slope.

Next, the coating film dried in S2) is cured to form a hard coating layer to produce a foldable hard coating film.

The curing can be photo curing or thermosetting, but preferably performs a UV curing process. The irradiation amount of UV light for curing is preferably about 0.01 to 10 J / cm 2, more preferably 0.1 to 2 J / cm 2.

The hard coat layer produced through the above steps has a thickness of 10 to 200 mu m at the non-folded portion. If the thickness is thinner than the above range, the hardness of the hard coat layer may not be sufficient. If it is thicker than the above thickness, cracks may occur during handling.

As mentioned above, the foldable hard coating film containing such a hard coating layer can be applied to a foldable display, which has recently been in the limelight because the thickness of the folded portion is reduced and cracks are not generated when the film is folded.

For example, the foldable hard coating film according to the present invention can be used as a substitute for a cover glass such as a display of LCD, OLED, LED, FED or various mobile communication terminals, a touch panel of a smart phone or a tablet PC, It can be used as a usable or functional layer.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention. Such variations and modifications are intended to be within the scope of the appended claims. In the following, "%" and "part" representing the content are on a mass basis unless otherwise specified.

Manufacturing example  One: Hardness Hard coating  Composition for forming

10 parts by weight of urethane acrylate (10-function, trade name, SC2153), 10 parts by weight of pentaerythritol triacrylate, 50 parts by weight of an organic acrylate having an average number of functional groups of 6.5 and 50 parts by weight of nano-silica sol (12 nm, ), 20 parts by weight of methyl ethyl ketone, 7 parts by weight of propylene glycol monomethyl ether, 2.5 parts by weight of a photoinitiator (Shibasai, I-184) and 0.5 parts by weight of a leveling agent (BYK Chemicals, BYK3570) Followed by filtration using a PP filter to prepare a composition for forming a hard hard coating layer.

Example  One: Foldable Hard coating  Production of film

A triacetylcellulose film (80 占 퐉) was selected as a base film and divided into three regions.

First, in one region, the hard coat hard coat layer composition prepared in Preparation Example 1 was coated on one side of a triacetyl cellulose film (80 占 퐉) in a width direction of 5 cm so as to have a coating layer thickness of 20 占 퐉. The thickness of the coating layer means the thickness after final curing.

Next, the coating thickness was continuously changed to 2 占 퐉 in the width direction so that the thickness of the coating layer was 5 占 퐉 in the two areas.

Next, a total of 12 cm length was coated by coating 5 cm in the width direction so that the thickness of the coating layer was 20 μm in the three regions.

Next, after drying at 100 DEG C for 1 minute, UV irradiation at 500 mJ / cm < ² > was performed to cure the film, thereby producing a hard-hardenable hard coat film having a surface thickness deviation.

Example  2: Foldable Hard coating  Production of film

The procedure of Example 1 was repeated except that the hardcoat hard-coated film was prepared by varying the thickness of the hardcoat layer.

The composition for forming a hard coat layer prepared in Preparation Example 1 was coated on one side of a triacetyl cellulose film (80 mu m) to a thickness of 5.5 m so as to have a coating layer thickness of 20 mu m.

Next, the coating thickness was changed continuously so that the thickness of the coating layer was 3 占 퐉, followed by 1 cm coating.

Next, the coating layer was coated to a thickness of 5.5 m to form a coating layer having a thickness of 20 m, followed by drying and curing as described in Example 1 to prepare a hard-coated, foldable hardcoat film.

Comparative Example 1: Hard coating  Production of film

The hard hard coating solution of Preparation Example 1 was coated on one side of a triacetyl cellulose film (80 占 퐉) so that the coating layer had a thickness of 20 占 퐉, and then a hard hard coating film was produced in the same manner as in Example 1 Respectively.

Experimental Example  One: Hard coating  Measurement and analysis of physical properties of film

The physical properties of the hard coating films prepared in Examples and Comparative Examples were measured as follows, and the results are shown in Table 1 below.

(1) Pencil Hardness: A pencil was set in a direction of 45 degrees under a load of 500 g, and the coating film was fixed on a glass so that the coated surface was directed to the side of the coated surface. After 5 evaluations with a pencil having each pencil hardness, The pencil hardness was indicated by the hardness which is not.

(2) Scratch resistance: The coating film was fixed to the glass with an adhesive, and the surface was reciprocated 10 times with a load of 1 kg using a steel wool (# 0000) having an area of 2 cm * 2 cm on the coated surface.

1: Less than 10 scratches

2: Less than 20 scratches

3: Less than 30 scratches

4: More than 30 scratches

(3) Bending test

The folded portion of the film was set on the rod having the diameter, and the coated surface was set inward. Then, the film was folded in half, and the bending operation was repeated 200,000 times. After the bending, it was confirmed whether or not a crack occurred in the folded portion of the film.

Unfolded pencil hardness Abrasion resistance Folding site bending test Example 1 8H One No crack after bending with diameter 5mm 200,000 times Example 2 8H One No crack after bending 2mm diameter 200mm bend Comparative Example 1 8H One Cracks after bending of 5mm diameter 200,000 times

Referring to Table 1, the hard coating films of Examples and Comparative Examples are excellent in pencil hardness and scratch resistance, indicating that they are hard hard coating films.

However, in the bending test, it was found that cracks were not generated in the hard coating films of Examples 1 and 2 in which folding portions existed, but cracks occurred in the hard coating film of Comparative Example 1.

The foldable hard coating film according to the present invention can be used as a hard hard coating composition in place of the glass of an apparatus such as various foldable displays or as various functional layers.

1: substrate film 3: hard coat layer
3a: folded portion 3b: non-folded portion
10: Foldable hard coating film

Claims (8)

A foldable hard coating film on which a hard coat layer having a foldable portion and a non-folded portion foldable on the basis of a folding line is formed on a base film. The foldable hard coating film according to claim 1, wherein the folding line forms a straight line along the vertical or horizontal direction of the hard coating film. The foldable hard coating film according to claim 1, wherein one or more fold lines are formed. The foldable hard coating film according to claim 1, wherein the thickness of the folded portion and the non-folded portion satisfy the following formula (1)
[Equation 1]

(In the above formula (1)
Ta is the average thickness of the folded portion,
Tb is the average thickness of the unfolded portion) The foldable hard coating film of claim 1, wherein the folded portion and the non-folded portion are connected by a gentle slope. The foldable hard coating film according to claim 1, wherein the hard coating film is a hard hard coating film having a pencil hardness of 5H or more. The foldable hard coating film according to claim 1, wherein the hard coating film is cracked in a 5 mm mandrel test for 200,000 fold flexing. A display comprising a foldable hard coating film according to any one of claims 1 to 7.

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