KR102346783B1 - Cover window plate and image display device having the same - Google Patents

Abstract

The present invention relates to a cover window substrate, and more particularly, by providing an organic-inorganic hybrid hard coating layer on at least one surface of a polymer base film and having a pencil hardness of 4H or more under a load of 1 kg, the substrate under severe conditions of high temperature and high humidity It relates to a cover window substrate having excellent durability and optical properties when applied to a product by significantly reducing the occurrence of warpage, and having excellent anti-finger performance on the surface, and an image display device having the same.

Description

COVER WINDOW PLATE AND IMAGE DISPLAY DEVICE HAVING THE SAME

The present invention relates to a cover window substrate and an image display device having the same, and to a cover window substrate in which warpage of the substrate is minimized even under conditions of high temperature and high humidity.

Recently, various 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 shocks, 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.

In recent years, various studies have been conducted on optical plastic covers having strength or scratch resistance corresponding to tempered glass while securing flexibility and impact resistance. In general, as for the optical transparent plastic cover material, which has more flexibility than tempered glass, 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 required physical properties 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 the 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 curling 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 cover window substrate capable of realizing high hardness while being a non-glass product.

An object of the present invention is to provide a cover window substrate that minimizes warpage even under severe conditions of high temperature and high humidity.

Another object of the present invention is to provide an image display device including the cover window substrate.

1. A cover window substrate comprising an organic-inorganic hybrid hard coating layer on at least one surface of the polymer-based film, and having a pencil hardness of 4H or more under a load of 1 kg.

2. The cover window substrate according to 1 above, wherein the pencil hardness under a load of 1 kg is 6H or more.

3. In the above 1, the hard coating layer is nano silica, vinyltrimethoxysilane, vinyltriethoxysilane, glycidoxypropylmethyldimethoxysilane, epoxycyclohexylethyltrimethoxysilane, glycidoxypropyltrimethyl A cover window substrate comprising at least one inorganic compound selected from the group consisting of oxysilane, glycidoxypropyltriethoxysilane, methacryloxypropyltrimethoxysilane and methacryloxypropyltriethoxysilane.

4. The cover window substrate according to the above 3, wherein the hard coat layer is made of a composition for forming a hard coat layer further comprising a polymerizable compound, a polymerization initiator, and a solvent.

5. The cover window substrate according to the above 3, wherein the inorganic compound is included in an amount of 100 to 260 parts by weight based on 100 parts by weight of the polymerizable compound.

6. In the above 3, the polymerizable compound is perfluoroalkyl acrylate, hydroxyethyl (meth) acrylate, hexanediol diacrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) ) acrylate, ethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, tripropylene glycol diacrylate, trimethylolpropane trioxyethyl (meth)acrylate, tricyclodecanedi At least one selected from the group consisting of methanol diacrylate and dipentaerythritol hexa(meth)acrylate), the substrate of the cover window.

7. The cover window substrate according to the above 1, wherein the water contact angle of the hard coating layer is 80° to 120°.

8. The cover window substrate according to 1 above, wherein the hard coating layer has a thickness of 10 to 40 μm.

9. The cover window substrate according to the above 1, wherein the polymer base film is heat-treated under the conditions of a heat deflection temperature (HDT) of the polymer ± 20 ° C or a glass transition temperature (Tg) ± 20 ° C.

10. The cover window substrate according to 1 above, wherein the polymer base film is heat-treated at 90° C. to 110° C. for 120 minutes to 240 minutes.

11. The cover window substrate according to the above 10, wherein the polymer base film is cooled at 25° C. to 60° C. for 1 minute to 15 minutes after the heat treatment.

12. The cover window substrate according to 11 above, wherein the polymer-based film is further cooled at a lower temperature than the cooling step after the cooling.

13. The above 1, wherein the polymer base film is polymethyl (meth) acrylate (PMMA), polycarbonate (PC), polyethylene terephthalate (PET), polyimide (PI), polyamide (PA), cycloolefin A cover window substrate comprising at least one from the group consisting of a polymer (COP), a cycloolefin copolymer (COC), a PMMA/PC copolymer, and a PMMA/PC/PMMA copolymer.

14. The cover window substrate according to the above 1, wherein the thickness of the polymer base film is 0.2 to 1.0 mm.

15. The cover window substrate of 1 above, further comprising a non-display light blocking layer on the other surface of the surface on which the hard coating layer of the polymer base film is formed.

16. The cover window substrate according to the above 15, further comprising a protective film on both sides, respectively.

17. The cover window substrate according to the above 16, wherein the shrinkage ratio of the protective film on the upper surface is 100 ppm or less, and the shrinkage ratio of the protective film on the lower surface is 100 ppm or more under the conditions of 60°C and 90%RH.

18. The cover window substrate according to the above 16, wherein under the conditions of 85°C and 85%RH, the shrinkage ratio of the protective film on the upper surface is 100 ppm or less, and the shrinkage ratio of the protective film on the lower surface is 100 ppm or more.

19. In the above 1, after leaving the substrate at 60 ℃, RH90%, the amount of warpage measured at room temperature (25 ℃) with the hard coating layer facing upward is -1.0mm (reverse curl) to +1.0mm (normal curl) phosphorus, cover window substrate.

20. In the above 1, after leaving the substrate at 85 ℃, RH85%, the amount of warpage measured at room temperature (25 ℃) with the hard coating layer facing upward is -1.0mm (reverse curl) to +1.0mm (normal curl) phosphorus, cover window substrate.

21. An image display device comprising the cover window substrate of any one of 1 to 20 above.

The cover window substrate of the present invention can realize high hardness even though it is a non-glass polymer product, so it is suitable for realizing the weight reduction of the product, and the manufacturing cost is also low, so that it is very economical.

The cover window substrate of the present invention remarkably reduces the occurrence of warpage of the substrate under severe conditions of high temperature and high humidity, thereby exhibiting excellent durability and optical properties when applied to products.

The cover window substrate of the present invention has excellent anti-fingerprint performance on the surface even without a separate anti-fingerprint layer.

1 shows a criterion for measuring the occurrence of warpage in the present invention.

The present invention relates to a cover window substrate, and more particularly, by including an organic-inorganic hybrid hard coating layer on at least one surface of a polymer base film and having a pencil hardness of 4H or more under a load of 1 kg, the substrate under severe conditions of high temperature and high humidity It relates to a cover window substrate having excellent durability and optical properties when applied to a product by significantly reducing the occurrence of warpage, and having excellent anti-finger performance on the surface, and an image display device having the same.

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

In the case of manufacturing the cover window substrate based on the polymer base film, a hard coating layer may be formed on the surface of the film in terms of strength improvement. However, due to the inherent shrinkage rate of the polymer constituting the base film and the stress remaining due to thermal change during the manufacture of the base film, there is a problem in that each layer is lifted under the harsh conditions of high temperature and high humidity. As a result, the durability of the product is lowered, and there is a problem of lowering the visibility of the image to be implemented.

Accordingly, the present invention solves the above problem by forming an organic-inorganic hybrid hard coating layer having a specific strength value on the surface of the polymer substrate film, thereby remarkably reducing the warpage under high temperature and high humidity conditions, and in addition, by the hard coating layer Anti-finger properties of the surface can also be implemented.

The cover window substrate 10 according to the present invention includes a polymer base film and an organic-inorganic hybrid hard coating layer.

The organic-inorganic hybrid hard coating layer is formed on at least one surface of the polymer base film to exhibit a pencil hardness of 4H or more under a load of 1 kg on the surface of the substrate.

The present inventors have derived that the pencil hardness under a load of 1 kg suitable for a cover window substrate is 4H or more, and in the case of a substrate based on a conventional polymer film, it does not satisfy the pencil hardness of 4H or more under the above conditions.

The cover window substrate according to the present invention includes an organic-inorganic hybrid hard coating layer, so that the pencil hardness under 1 kg load can be implemented to be 4H or more.

When the pencil hardness of the substrate is less than 4H, the cover substrate does not provide sufficient strength, and when the pencil hardness under 1 kg load is 6H or more, the above-described effect can be further improved.

The organic-inorganic hybrid hard coating layer according to the present invention is formed by combining an organic compound and an inorganic compound, and the pencil hardness of the hard coating layer is implemented by controlling the type of organic-inorganic compound used, the mixing ratio, the process conditions when forming the coating layer, etc. can be

The organic-inorganic hybrid hard coating layer may be formed by applying a composition for forming an organic-inorganic hybrid coating layer further comprising a polymerizable compound, a polymerization initiator, and a solvent in addition to an inorganic compound on a polymer base film.

The type of inorganic compound usable in the present invention is not particularly limited, but for example, nano silica, vinyltrimethoxysilane, vinyltriethoxysilane, glycidoxypropylmethyldimethoxysilane, epoxycyclohexylethyltrimethoxy silane, glycidoxypropyltrimethoxysilane, glycidoxypropyltriethoxysilane, methacryloxypropyltrimethoxysilane, methacryloxypropyltriethoxysilane, etc. can be used. In particular, vinyltrimethoxysilane, vinyltriethoxysilane, methacryloxypropyltrimethoxysilane, and methacryloxypropyltriethoxysilane are preferable, and these may be used alone or in combination of two or more.

The content of the inorganic compound is not particularly limited, but, for example, may be included in an amount of 100 to 260 parts by weight based on 100 parts by weight of the polymerizable compound. It is mixed to improve the compressibility of the entire structure, so that the coating thickness can be thinned, the adhesion with the polymer base film can be improved, and the flatness and high hardness of the coating layer can be realized. Accordingly, it is determined that warpage can be minimized under conditions of high temperature and high humidity, excellent durability can be realized even when forming a curved surface, and fingerprint resistance of the surface can be improved.

In addition, the inorganic compound may be preferably included in an amount of 120 to 260 parts by weight, and in this case, the effect of strengthening the hardness may be further improved.

The kind of polymerizable compound that can be used in the present invention is not particularly limited, but may be polymerized including an acrylate-based monomer, and specifically, the acrylate-based monomer is perfluoroalkyl acrylate, hydroxyethyl (meth) Acrylate, hexanediol diacrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, ethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate , tripropylene glycol diacrylate, trimethylol propane trioxyethyl (meth) acrylate, tricyclodecane dimethanol diacrylate, and dipentaerythritol hexa(meth) acrylate, and these are singly or Two or more types may be mixed and used.

In addition, as the polymerizable compound, it is preferable to use a fluorine-based binder resin in terms of improving anti-fingerprint properties, and, for example, it is more preferable to use a polymerized resin including perfluoroalkyl acrylate.

The kind of polymerization initiator that can be used in the present invention is not particularly limited, but for example, an acetophenone-based compound, a benzophenone-based compound, a triazine-based compound, a biimidazole-based compound, a thioxanthone-based compound, or an oxime ester-based compound. At least one compound selected from the group consisting of may be used, and preferably, an oxime ester-based compound is used.

Specific examples of the acetophenone-based compound include diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzyldimethyl ketal, 2-hydroxy-1-[4-(2) -Hydroxyethoxy)phenyl]-2-methylpropan-1-one, 1-hydroxycyclohexylphenylketone, 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropane-1- One, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butan-1-one, 2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propane -1-one, 2-(4-methylbenzyl)-2-(dimethylamino)-1-(4-morpholinophenyl)butan-1-one, and the like.

Specific examples of the benzophenone-based compound include benzophenone, methyl o-benzoylbenzoate, 4-phenylbenzophenone, 4-benzoyl-4'-methyldiphenylsulfide, 3,3',4,4'-tetra (tert-butylperoxycarbonyl)benzophenone, 2,4,6-trimethylbenzophenone, etc. are mentioned.

Specific examples of the triazine-based compound include 2,4-bis(trichloromethyl)-6-(4-methoxyphenyl)-1,3,5-triazine, 2,4-bis(trichloromethyl) -6- (4-methoxynaphthyl) -1,3,5-triazine, 2,4-bis (trichloromethyl) -6-piperonyl-1,3,5-triazine, 2,4 -Bis(trichloromethyl)-6-(4-methoxystyryl)-1,3,5-triazine, 2,4-bis(trichloromethyl)-6-[2-(5-methylfuran- 2-yl)ethenyl]-1,3,5-triazine, 2,4-bis(trichloromethyl)-6-[2-(furan-2-yl)ethenyl]-1,3,5- Triazine, 2,4-bis(trichloromethyl)-6-[2-(4-diethylamino-2-methylphenyl)ethenyl]-1,3,5-triazine, 2,4-bis(trichloro and romethyl)-6-[2-(3,4-dimethoxyphenyl)ethenyl]-1,3,5-triazine.

Specific examples of the biimidazole-based compound include 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenylbiimidazole, 2,2'-bis(2, 3-dichlorophenyl)-4,4',5,5'-tetraphenylbiimidazole, 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetra(alkoxyphenyl) Biimidazole, 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetra(trialkoxyphenyl)biimidazole, 2,2-bis(2,6-dichlorophenyl) -4,4'5,5'-tetraphenyl-1,2'-biimidazole or an imidazole compound in which the phenyl group at the 4,4',5,5' position is substituted with a carboalkoxy group; and preferably 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenylbiimidazole, 2,2'-bis(2,3-dichlorophenyl)-4 ,4',5,5'-tetraphenylbiimidazole, 2,2-bis(2,6-dichlorophenyl)-4,4'5,5'-tetraphenyl-1,2'-biimidazole, etc. can be heard

Specific examples of the thioxanthone-based compound include 2-isopropylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone, 1-chloro-4-propoxythioxanthone and the like.

Specific examples of the oxime ester compound include: o-ethoxycarbonyl-α-oxyimino-1-phenylpropan-1-one, 1,2-octadione,-1-(4-phenylthio)phenyl; -2-(o-benzoyloxime), ethanone,-1-(9-ethyl)-6-(2-methylbenzoyl-3-yl)-,1-(o-acetyloxime), and the like; Commercially available products include CGI-124 (Shiba Geigisa), CGI-224 (Ciba Geigisa), Irgacure OXE-01 (BASF), Irgacure OXE-02 (BASF), N-1919 (Adeka), NCI-831 ( Adecas), etc.

In addition, the photopolymerization initiator (C) may further include a photopolymerization initiation adjuvant in order to improve the sensitivity of the photosensitive resin composition of the present invention. The photosensitive resin composition according to the present invention contains a photopolymerization initiation adjuvant, thereby further increasing the sensitivity and improving productivity.

The kind of solvent that can be used in the present invention is not particularly limited, but for example, ethylene glycol monoalkyl ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether and ethylene glycol monobutyl ether; diethylene glycol dialkyl ethers such as diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol ethyl methyl ether, diethylene glycol dipropyl ether, and diethylene glycol dibutyl ether; ethylene glycol alkyl ether acetates such as methyl cellosolve acetate, ethyl cellosolve acetate, ethylene glycol monobutyl ether acetate, and ethylene glycol monoethyl ether acetate; alkylene glycol alkyl ether acetates such as propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, methoxybutyl acetate, and methoxypentyl acetate; propylene glycol monoalkyl ethers such as propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, and propylene glycol monobutyl ether; propylene glycol dialkyl ethers such as propylene glycol dimethyl ether, propylene glycol diethyl ether, propylene glycol ethyl methyl ether, propylene glycol dipropyl ether, propylene glycol propyl methyl ether, and propylene glycol ethyl propyl ether; propylene glycol alkyl ether propionates such as propylene glycol methyl ether propionate, propylene glycol ethyl ether propionate, propylene glycol propyl ether propionate, and propylene glycol butyl ether propionate; butyldiol monoalkyl ethers such as methoxybutyl alcohol, ethoxybutyl alcohol, propoxybutyl alcohol and butoxybutyl alcohol; butanediol monoalkyl ether acetates such as methoxybutyl acetate, ethoxybutyl acetate, propoxybutyl acetate, and butoxybutyl acetate; butanediol monoalkyl ether propionates such as methoxybutyl propionate, ethoxybutyl propionate, propoxybutyl propionate and butoxybutyl propionate; dipropylene glycol dialkyl ethers such as dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether, and dipropylene glycol methyl ethyl ether; aromatic hydrocarbons such as benzene, toluene, xylene, and mesitylene; ketones such as methyl ethyl ketone, acetone, methyl amyl ketone, methyl isobutyl ketone and cyclohexanone; alcohols such as ethanol, propanol, butanol, hexanol, cyclohexanol, ethylene glycol, and glycerin; Methyl acetate, ethyl acetate, propyl acetate, butyl acetate, ethyl 2-hydroxypropionate, methyl 2-hydroxy-2-methylpropionate, ethyl 2-hydroxy-2-methylpropionate, methyl hydroxyacetate, ethyl hydroxyacetate , butyl hydroxyacetate, methyl lactate, ethyl lactate, propyl lactate, butyl lactate, methyl 3-hydroxypropionate, ethyl 3-hydroxypropionate, propyl 3-hydroxypropionate, butyl 3-hydroxypropionate, 2-hydroxy -3-methylbutanoate, methyl methoxyacetate, ethyl methoxyacetate, propyl methoxyacetate, butyl methoxyacetate, methyl ethoxyacetate, ethyl ethoxyacetate, propyl ethoxyacetate, butyl ethoxyacetate, propoxy Methyl acetate, ethyl propoxy acetate, propyl propoxy acetate, butyl propoxy acetate, methyl butoxy acetate, ethyl butoxy acetate, propyl butoxy acetate, butyl butoxy acetate, methyl 2-methoxypropionate, 2-methoxypropionic acid Ethyl, 2-methoxypropyl propionate, 2-methoxybutyl propionate, 2-ethoxypropionate methyl, 2-ethoxypropionate ethyl, 2-ethoxypropionate propyl, 2-ethoxypropionate butyl, 2-butoxypropionate methyl , 2-butoxypropionate ethyl, 2-butoxypropionate propyl, 2-butoxypropionate butyl, 3-methoxymethylpropionate, 3-methoxyethylpropionate, 3-methoxypropylpropionate, 3-methoxybutylpropionate, 3-methyl ethoxypropionate, 3-ethyl ethoxypropionate, 3-ethoxypropionate propyl, 3-ethoxypropionate butyl, 3-propoxypropionate methyl, 3-propoxypropionate ethyl, 3-propoxypropionate propyl, 3 -esters, such as butyl propoxy propionate, 3-butoxy propionate methyl, 3-butoxy propionate ethyl, 3-butoxy propionate propyl, 3-butoxy propionate butyl; cyclic ethers such as tetrahydrofuran and pyran; Cyclic esters, such as (gamma)-butyrolactone, etc. are mentioned. The solvents illustrated here can be used individually or in mixture of 2 or more types, respectively.

Esters such as alkylene glycol alkyl ether acetates, ketones, butanediol alkyl ether acetates, butanediol monoalkyl ethers, 3-ethoxy ethyl propionate, 3-methoxy methyl propionate, etc. may be preferably used, more preferably propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, cyclohexanone, methoxybutyl acetate, methoxybutanol, 3-ethoxypropionate ethyl, 3-methoxypropionic acid methyl and the like can be used.

The hard coat layer may be formed by applying the composition for forming an organic-inorganic hybrid hard coat layer comprising the above-mentioned components to the polymer base film, and the application method is not particularly limited, for example, a die coater, an air knife, a reverse It may be carried out by a known method such as roll, spray, blade, casting, gravure, spin coating, and the like.

After the coating process, a curing process may be further performed, and the curing method is not particularly limited, and for example, photocuring or thermal curing alone, or thermal curing after photocuring, photocuring after thermal curing, etc. method can be done.

When the curing process proceeds to a photocuring process after thermal curing, the thermal curing may be performed at 60 to 90° C. for 60 seconds to 300 seconds, and the photocuring is performed using light in a region of 320 to 400 nm with an amount of 400 to 700 mJ/cm ² It can be carried out by controlling the curing time.

The water contact angle of the organic-inorganic hybrid hard coating layer according to the present invention may be 80° to 120°, preferably 100° to 120°. When the water contact angle within the above range is satisfied, the anti-fingerprint property of the surface is improved, thereby further improving the visibility of the image to be implemented.

The thickness of the organic-inorganic hybrid hard coating layer according to the present invention is not particularly limited, but may be, for example, 10 to 40 μm, preferably 15 to 30 μm. When the thickness in the above range is satisfied, the effect of improving the pencil hardness can be realized.

The polymer substrate film according to the present invention serves as a substrate on which the organic-inorganic hybrid hard coating layer is formed, and as long as it has an appropriate strength to facilitate the formation of the hard coating layer, the type thereof is not particularly limited.

Specific examples of the material of the polymer base film usable in the present invention include polymethyl (meth) acrylate (PMMA), polycarbonate (PC), polyethylene terephthalate (PET), polyimide (PI), polyamide ( PA), cycloolefin polymer (COP), cycloolefin copolymer (COC), PMMA/PC copolymer, and PMMA/PC/PMMA copolymer, etc., preferably polymethyl (meth)acrylate (PMMA) can be used

The thickness of the polymer base film according to the present invention is not particularly limited, but may be, for example, 0.2 mm to 1.0 mm, and when the thickness range is satisfied, an effect of satisfying a high hardness of 4H or more can be realized.

The method of forming the polymer base film according to the present invention is not particularly limited, but may be formed by extruding the above-described polymer material under specific temperature and pressure conditions.

More specifically, the extrusion process may be performed by dissolving the polymer material under a temperature equal to or higher than the melting point of the polymer material and then discharging it through an extrusion die at a predetermined pressure, and a plate-shaped polymer base film like the base film of the present invention. When forming, it may be carried out in a process of winding the extruded polymer material while stretching it with a predetermined tension or more.

On the other hand, during the stretching process, the polymer is rapidly cooled, and in this process, residual stress is generated inside the film. There is a difference between the roughness and the denseness of the tissue.

As such, when residual stress is present in the film, phenomena such as warpage due to distortion, shrinkage and expansion may occur during additional thermal processing, and there is a problem in that it is easy to peel from the additional laminate on the upper part.

The polymer base film according to the present invention may be one that has been subjected to additional heat treatment after manufacturing, and specifically, it may be heat-treated under the conditions of a heat deflection temperature (HDT) of the polymer ±20°C or a glass transition temperature (Tg) ±20°C. In the present invention, ±20°C is a concept including -20°C to +20°C at the reference point (heat deflection temperature (HDT) or glass transition temperature (Tg) of the polymer).

In this case, the residual stress generated during the manufacturing process may be relieved to compensate for the problem of durability deterioration occurring during additional thermal processing.

The heat treatment process of the polymer base film may be performed at 90° C. to 110° C. for 60 minutes to 240 minutes, and when performed under the above conditions, residual stress can be effectively relieved.

The polymer base film according to the present invention may be cooled at 25° C. to 60° C. for 1 minute to 15 minutes after the heat treatment process, and in this case, the effect of resolving residual stress can be further improved.

In addition, the polymer base film according to the present invention may be further cooled after the cooling step at a temperature lower than the temperature of the cooling step, and in this case, the above-described effect can be further improved.

The cover window substrate according to the present invention may further include a non-display light blocking layer on the other surface of the surface on which the hard coating layer of the polymer base film is formed.

In the present invention, "front" means the viewer side of the image display device based on the member, and "rear" means the other side of the viewer side.

The light blocking layer of the non-display part according to the present invention serves to hide the part to be covered in the image display device and visually beautify it, and its material and shape are not particularly limited, but for example, it is formed in a concave-convex structure and has a three-dimensional structure. It may include a three-dimensional pattern that can implement , specific examples, it may include a pattern such as an IR sensor, a camera opening, a home key hole, a speaker hole, an icon.

In addition, the non-conductive wave pattern includes a colorant, an alkali-soluble resin, a polymerizable compound, a polymerization initiator, a solvent, and the like, and may be formed of a photolithography-capable composition for forming a non-conductive color pattern, and each component is used in the art. As long as it is commonly used, it may be used without particular limitation.

As the colorant, any colorant known in the art may be used without particular limitation. The type of the colorant is not particularly limited in order to realize the color required by the user, for example, white, red, green, blue dyes and pigments; dyes and pigments such as yellow, orange, violet and brown for toning; Carbon black etc. are mentioned. These can be used individually or in mixture of 2 or more types.

The colorant may further include metal powder, white pigment, fluorescent pigment, and the like, if necessary.

The pigment may be an inorganic pigment or an organic pigment.

The kind of inorganic pigment is not specifically limited, For example, barium sulfate, lead sulfate, titanium oxide, yellow lead, bengal, chromium oxide, carbon black, etc. are mentioned.

The type of organic pigment is not particularly limited, and for example, various pigments having CI (color index) numbers commonly used in the art may be mentioned, and these may be used alone or in combination of two or more. .

The cover window substrate according to the present invention may further include a protective film on both sides to prevent external defects such as surface scratches during the delivery process of the substrate after manufacturing, and the protective film may be removed when applied to the final product. have.

The protective film according to the present invention may be one in which the protective film is disposed on both sides of the substrate, that is, on the upper part of the polymer base film provided with the hard coating layer and on the lower part of the non-display part light blocking layer, respectively.

The protective film according to the present invention is not particularly limited as long as it has excellent transparency, mechanical strength, thermal stability, moisture shielding property, isotropy, etc. For example, a polyester film such as polyethylene terephthalate, polyethylene isophthalate, and polybutylene terephthalate ; Cellulose films, such as diacetyl cellulose and triacetyl cellulose; polycarbonate film; Acrylic films, such as polymethyl (meth)acrylate and polyethyl (meth)acrylate; styrenic films such as polystyrene and acrylonitrile-styrene copolymer; polyolefin-based films such as polyethylene, polypropylene, polyolefin having a cyclo-based or norbornene structure, and an ethylenepropylene copolymer; polyimide-based film; polyethersulfone-based film; A conventional film such as a sulfone-based film may be used, but is not limited thereto.

In the present invention, the shrinkage rate of the protective film on the upper surface (protective film on the upper part of the polymer substrate film) at 60°C and 90% RH may be 100 ppm or less, and the protective film on the lower surface (the lower part of the light blocking layer of the non-display part) (protective film) under the conditions of 60°C and 90%RH, the shrinkage rate may be 100ppm or more. The conditions of 60° C. and 90% RH mean that it is stable at high temperature and high humidity, and when the shrinkage rate described above is satisfied in this condition, by bonding both sides of the cover plastic, the occurrence of warpage of the substrate can be minimized.

In addition, in the present invention, the shrinkage rate of the protective film on the upper surface (protective film on the upper part of the polymer substrate film) at 85 ℃ and 85% RH may be 100 ppm or less, and the protective film on the lower surface (of the non-display part light blocking layer) Under the conditions of 85 ℃ and 85% RH of the lower protective film), the shrinkage rate may be 100 ppm or more. The conditions of 85 ℃ and 85% RH mean that stability under more severe conditions compared to 60 ℃ and 90% RH was evaluated, and when the shrinkage rate described above is satisfied in this condition, by bonding both sides of the cover plastic, The occurrence of warpage can be minimized.

In addition, the peeling force of the protective film of the upper surface may be 10 to 100N/25mm, the peeling force of the lower protective film may be 100 to 300N/25mm. In this case, by bonding both surfaces of the cover plastic, it is possible to minimize the occurrence of warpage of the substrate.

The cover window substrate according to the present invention including the above configuration can significantly reduce the occurrence of warpage under high temperature and high humidity conditions. For example, after leaving the substrate at 60°C and RH90%, the hard coating layer faces upward The amount of deflection measured at room temperature (25° C.) may be -1.0 mm (reverse curl) to +1.0 mm (normal curl), preferably -0.5 to +0.5 mm.

After leaving the substrate at 85°C, RH85%, the amount of warpage measured at room temperature (25°C) with the hard coating layer facing upward may be -1.0mm (reverse curl) to +1.0mm (static curl), preferably It may be -0.5 to +0.5 mm.

In the present invention, the occurrence of warpage means a case in which lifting (h1) occurs at the tip of the substrate under high temperature and high humidity conditions or lifting (h2) occurs inside the substrate, and the amount of warpage is after input to high temperature and high humidity conditions. , refers to the maximum height of the part that floats without being in close contact with the floor when the cover window substrate is placed on a flat surface under room temperature (25° C.) conditions (see FIG. 4).

More specifically, the amount of warpage can be expressed by measuring after making the hard coating layer go upward. When the amount of warpage is +, it means bending toward the hard coating layer (Junkal), and when the amount of warpage is -, it means bending toward the light-shielding side ( reverse curl).

<Image display device>

The present invention relates to an image display device including the cover window substrate. The image display device of the present invention may further include a configuration known in the art in addition to the above configuration.

Hereinafter, preferred embodiments are presented to help the understanding of the present invention, but these examples are merely illustrative of the present invention and do not limit the appended claims, and are within the scope and spirit of the present invention. It is obvious to those skilled in the art that various changes and modifications are possible, and it is natural that such variations and modifications fall within the scope of the appended claims.

Example and comparative example

Example One

<Production of polymer base film>

The polymethyl methacrylate film was heated at 100° C. for 120 minutes, cooled at 60° C. for 10 minutes, and subjected to step-by-step heat treatment of cooling at room temperature (25° C.) to prepare a polymer base film (A-1).

<Manufacture of cover window substrate>

After applying the composition for organic-inorganic hybrid hard coating having the components and compositions shown in Table 1 on one side of the heat-treated polymer base film, drying at 90 ° C. for 90 seconds, and light in the ultraviolet wavelength range of 315 and 365 nm to 600 mJ By curing, a hard coating layer having a final thickness of 30 μm was formed.

Next, a non-display light blocking layer was formed on the other surface of the polymer base film on which the hard coating layer was formed, and then dried at 80° C. for 60 minutes.

Thereafter, a PET base film having a peel force of 80N/25mm and a shrinkage rate of 60ppm under the conditions of 60°C and 90%RH on the upper part of the polymer base film (the side on which the hard coating layer is formed) is bonded using an acrylic adhesive, and the polymer A PET base film having a peeling force of 200N/25mm and a shrinkage rate of 150ppm under conditions of 60°C and 90%RH was bonded to the lower portion of the base film (on the non-display part light-shielding layer formation side) using an acrylic adhesive.

After bonding, a cover window substrate was manufactured by cutting the cell unit of a predetermined size at a speed of 100 mm/sec using a _{400 W CO 2 laser.}

Example 2

A cover window substrate was manufactured in the same manner as in Example 1, except that the thickness of the hard coating layer was formed to be 20 μm.

Example 3

A cover window substrate was manufactured in the same manner as in Example 1, except that the thickness of the hard coating layer was formed to be 10 μm.

Example 4

A cover window substrate was prepared in the same manner as in Example 1, except that the polymer substrate film (A-2), which was heat-treated at 80° C., was used.

Example 5

A substrate for a cover window was manufactured in the same manner as in Example 1, except that the polymer substrate film (A-3) heat-treated at 110° C. was used.

Example 6

A substrate for a cover window was prepared in the same manner as in Example 1, except that a polymer base film (A-4) that was not subjected to heat treatment was used.

Example 7 to 14 and comparative example 1 to 3

A substrate of a cover window was prepared in the same manner as in Example 1, except that the components and contents shown in Table 1 were used in preparing the hybrid coating layer.

division surface
Hardness write
film
(A) Hard coating layer thickness (㎛) Composition for forming a hard coat layer (component/comprising?c) inorganic compound
(B/wt%) polymeric compound
(C/wt%) polymerization initiator
(D/wt%) menstruum
(E/wt%) Example 1 9H A-1 30 B-1/34 C-1/16 D-1/6 E-1/ balance Example 2 7H A-1 20 B-1/34 C-1/16 D-1/6 E-1/ balance Example 3 5H A-1 10 B-1/34 C-1/16 D-1/6 E-1/ balance Example 4 9H A-2 30 B-1/34 C-1/16 D-1/6 E-1/ balance Example 5 9H A-3 30 B-1/34 C-1/16 D-1/6 E-1/ balance Example 6 9H A-4 30 B-1/34 C-1/16 D-1/6 E-1/ balance Example 7 7H A-1 30 B-1/28 C-1/22 D-1/6 E-1/ balance Example 8 9H A-1 30 B-1/36 C-1/14 D-1/6 E-1/ balance Example 9 6H A-1 30 B-1/19.5 C-1/30.5 D-1/6 E-1/ balance Example 10 9H A-1 30 B-1/37.5 C-1/12.5 D-1/6 E-1/ balance Example 11 9H A-1 30 B-2/34 C-1/16 D-1/6 E-1/ balance Example 12 9H A-1 30 B-3/34 C-1/16 D-1/6 E-1/ balance Example 13 9H A-1 30 B-1/34 C-1/17.5 D-1/6 E-1/ balance Example 14 9H A-1 30 B-1/34 C-1/18 D-1/6 E-1/ balance Comparative Example 1 3H A-1 30 B-1/18 C-1/32 D-1/6 E-1/ balance Comparative Example 2 3H A-1 30 B-1/16 C-1/34 D-1/6 E-1/ balance Comparative Example 3 3H A-1 30 B-1/14 C-1/36 D-1/6 E-1/ balance
A: Polymer base film
A-1: Polymethyl (meth)acrylate film heat-treated at 100°C
A-2: Polymethyl (meth)acrylate film heat-treated at 80°C
A-3: Polymethyl (meth)acrylate film heat-treated at 110°C
A-4: Polymethyl (meth)acrylate film that has not undergone a separate heat treatment

B: inorganic compound
B-1: Nanosilicasol:vinyltrimethoxysilane 67 weight ratio: 23 weight ratio
B-2: Nanosilicasol:bis(triethoxysilylpropyl)tetrasulfide 67 weight ratio: 23 weight ratio
B-3: Nanosilicasol: N-(3-acryloxy-2-hydroxypropyl)-3-aminopropyltrimethoxysilane 67 weight ratio: 23 weight ratio

C: polymerizable compound
C-1: Hydroxyethyl (meth) acrylate: Perfluoroalkyl acrylate 94 weight ratio: 6 weight ratio

D: polymerization initiator
D-1:Igracure184:Igracure2959 50 weight ratio: 50 weight ratio

E: solvent
E-1: PGMEA

For the surface hardness, according to JIS5400 for the hard coating layer, pencil hardness under a load of 1 kg was measured using a pencil manufactured by Mitsubishi.

experimental method

(1) Warpage occurrence evaluation ( amount of deflection )

After leaving the cover window substrates prepared according to Examples and Comparative Examples at 60° C. and RH90% for 48 hours, the hard coating layer was placed facing up, and at room temperature (25° C.), the largest of the floating parts without being in close contact with the flat bottom surface. The height was measured (refer to FIG. 1), and the results are shown in Table 2 below.

In the case of +, it means bending to the hard coating layer (positive curl), and in the case of -, it means bending toward the light-shielding side (reverse curl).

(2) anti-fingerprint evaluation

After dropping water droplets on the surface of the cover window substrate prepared according to Examples and Comparative Examples, the angle (water contact angle) between the surface and the water droplet was measured, and is shown in Table 2 below.

When the angle is within the range of 100° to 120°, excellent anti-fingerprint properties can be implemented, and most preferably, when the angle is 110° to 120°, the anti-fingerprint property is excellent.

(3) Impact resistance evaluation

The cover window substrates manufactured according to Examples and Comparative Examples were fixed on a jig with a hole of 50 mm in the center, and a 130 g iron bead was dropped from a predetermined height to measure the maximum height at which deformation, cracking, etc. occurred in appearance, The results are shown in Table 2 below.

(4) Durability evaluation

The surface of the cover window substrates prepared according to Examples and Comparative Examples were visually checked for scratches, cracks, and deformations using a 3-wavelength lamp, respectively. The length was measured, and the results are shown in Table 2 below.

If the long side length of the yellow zone of the cut surface is less than 80㎛, the visibility of the edge part is excellent, and if it is 80㎛ or more, the yellow part in the edge part may cause a problem to be recognized.

division amount of deflection anti-fingerprint impact resistance adhesion crack curved part flat part Example 1 +0.5 110° 25cm 100
/100 None None Example 2 +0.5 110° 25cm 100
/100 None None Example 3 +0.5 110° 24cm 100
/100 None None Example 4 +0.7 110° 25cm 100
/100 None None Example 5 +0.4 110° 25cm 100
/100 None None Example 6 +1.0 110° 25cm 100
/100 None None Example 7 +0.7 110° 25cm 100
/100 None None Example 8 -0.2 110° 25cm 90
/100 None None Example 9 +1.2 110° 25cm 100
/100 None None Example 10 -0.5 110° 25cm 80
/100 None None Example 11 +0.8 110° 25cm 70
/100 None None Example 12 +0.9 110° 25cm 60
/100 None None Example 13 +0.5 112° 25cm 100
/100 None None Example 14 +0.5 115° 25cm 100
/100 None None Comparative Example 1 +1.5 110° 22cm 100
/100 None None Comparative Example 2 +1.7 110° 22cm 100
/100 None None Comparative Example 3 +2.1 110° 22cm 100
/100 None None

As can be seen from Table 2, in the case of an embodiment having a hard coating layer according to the present invention, it can be confirmed that a product having a hardness of 6H or more and a warpage of +0.5mm can be produced.

However, in the case of Example 4, where the heat treatment temperature of the polymer substrate film was rather low, the warpage was slightly increased, and in the case of Example 5 where the heat treatment temperature was somewhat high, the haze was slightly increased, and the polymer substrate film without heat treatment was used. In the case of Example 6, it can be seen that the occurrence of warpage is increased compared to the other examples due to residual stress.

In Comparative Examples 1 to 3, which deviates from the hardness value according to the present invention, it was confirmed that the occurrence of warpage was significantly increased compared to Examples, and the impact resistance tablet was significantly lowered. In particular, as the content of the inorganic compound decreased compared to the polymerizable compound (Comparative Example 1 < Comparative Example 2 < Comparative Example 3), it was confirmed that the amount of warpage further increased.

Claims (21)

Including an organic-inorganic hybrid hard coating layer on at least one surface of the polymer base film,
The hard coating layer,
nano silica; and
Vinyltrimethoxysilane, vinyltriethoxysilane, glycidoxypropylmethyldimethoxysilane, epoxycyclohexylethyltrimethoxysilane, glycidoxypropyltrimethoxysilane, glycidoxypropyltriethoxysilane, methacryl It contains at least one inorganic compound selected from the group consisting of hydroxypropyltrimethoxysilane and methacryloxypropyltriethoxysilane,
A cover window substrate having a pencil hardness of 4H or higher under a load of 1 kg.
The cover window substrate according to claim 1, wherein the pencil hardness under a load of 1 kg is 6H or more.
delete The cover window substrate of claim 1 , wherein the hard coat layer is made of a composition for forming a hard coat layer further comprising a polymerizable compound, a polymerization initiator, and a solvent.
The cover window substrate of claim 4 , wherein the inorganic compound is included in an amount of 100 to 260 parts by weight based on 100 parts by weight of the polymerizable compound.
The method according to claim 4, wherein the polymerizable compound is perfluoroalkyl acrylate, hydroxyethyl (meth) acrylate, hexanediol diacrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylic Rate, ethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, tripropylene glycol diacrylate, trimethylolpropane trioxyethyl (meth)acrylate, tricyclodecane dimethanol di At least one selected from the group consisting of acrylate and dipentaerythritol hexa(meth)acrylate), the cover window substrate.
The cover window substrate of claim 1 , wherein the water contact angle of the hard coating layer is 80° to 120°.
The method according to claim 1, The thickness of the hard coating layer is 10 to 40㎛, the cover window substrate.
polymer base film; and
Including an organic-inorganic hybrid hard coating layer formed on at least one surface of the polymer base film,
The polymer base film is heat-treated under the conditions of ± 20 ° C. or glass transition temperature (Tg) ± 20 ° C of the heat deflection temperature (HDT) of the polymer,
A cover window substrate having a pencil hardness of 4H or higher under a load of 1 kg.
polymer base film; and
Including an organic-inorganic hybrid hard coating layer formed on at least one surface of the polymer base film,
The polymer base film is heat-treated at 90° C. to 110° C. for 120 minutes to 240 minutes,
A cover window substrate having a pencil hardness of 4H or higher under a load of 1 kg.
The cover window substrate of claim 10 , wherein the polymer base film is cooled at 25° C. to 60° C. for 1 minute to 15 minutes after the heat treatment.
The cover window substrate of claim 11 , wherein the polymer-based film is further cooled at a lower temperature than the cooling step after the cooling.
The method according to claim 1, wherein the polymer base film is polymethyl (meth) acrylate (PMMA), polycarbonate (PC), polyethylene terephthalate (PET), polyimide (PI), polyamide (PA), cycloolefin polymer ( COP), a cycloolefin copolymer (COC), a cover window substrate comprising at least one from the group consisting of PMMA / PC copolymer and PMMA / PC / PMMA copolymer.
The method according to claim 1, The thickness of the polymer base film is 0.2 to 1.0mm, the cover window substrate.
The cover window substrate of claim 1, further comprising a non-display light blocking layer on the other surface of the surface on which the hard coating layer of the polymer base film is formed.
The cover window substrate of claim 15 , further comprising a protective film on both surfaces.
An organic-inorganic hybrid hard coating layer formed on at least one surface of the polymer base film; and
It includes a protective film formed on both sides of the polymer base film, respectively,
Under the conditions of 60° C. and 90% RH, the shrinkage rate of the protective film on the upper surface of the polymer base film is 100 ppm or less, and the shrinkage rate of the protective film on the lower surface is 100 ppm or more,
A cover window substrate having a pencil hardness of 4H or higher under a load of 1 kg.
The cover window substrate of claim 17 , wherein under the conditions of 85° C. and 85% RH, the shrinkage ratio of the protective film on the upper surface is 100 ppm or less, and the shrinkage ratio of the protective film on the lower surface is 100 ppm or more.
The method according to claim 1, After leaving the substrate at 60 ℃, RH90%, the amount of warpage measured at room temperature (25 ℃) with the hard coating layer facing upward is -1.0mm (reverse curl) to +1.0mm (normal curl), cover window substrate.
The method according to claim 1, After leaving the substrate at 85 ℃, RH85%, the amount of warpage measured at room temperature (25 ℃) with the hard coating layer facing upward is -1.0mm (reverse curl) to +1.0mm (normal curl), cover window substrate.
An image display device comprising the cover window substrate according to any one of claims 1 to 2 and 4 to 20.

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