Optical laminate and image display device including the same

Abstract

To provide an optical laminate which is excellent in pencil hardness characteristics and can secure flex resistance, prevents cracking of a glass substrate by external impact while being excellent in process property because of causing no curl, and can prevent scattering of broken pieces of glass even when being broken.SOLUTION: There are provided an optical laminate which includes a glass substrate, a primer layer formed so as to cover the upper face and the side face of the glass substrate on the glass substrate, a substrate resin layer formed so as to cover the upper face and the side face of the primer layer on the primer layer, and a functional coating layer formed on the substrate resin layer, wherein the glass substrate is ultrathin glass having thickness of less than 100 μm, pencil hardness of the whole optical laminate is 2H or more, and a ratio of the total thickness of the primer layer, the substrate resin layer and the functional coating layer to the thickness of the glass substrate is controlled to a specific range; and an image display device including the same.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an optical laminate and an image display device including the same, and more specifically to an optical laminate of glass substrates that not only has excellent pencil hardness characteristics and can ensure flex resistance, and is easy to process because it does not curl, but also prevents the glass substrate from breaking due to external impact and, even if it does break, can prevent glass fragments from scattering, and an image display device including the same. [Background technology]

[0002] Recently, advances in display technology have led to the development of foldable displays, rollable displays, stretchable displays, etc. Accordingly, research into ultra-thin glass (UTG) with improved flexibility to protect these various types of displays is being actively conducted.

[0003] This type of ultra-thin glass is flexible and can be used in a variety of displays, so it requires excellent bending strength and surface roughness to improve display quality.

[0004] Generally, in order to reduce the possibility of scratches on the glass surface of the window glass when the display is in use and the possibility of breakage due to dropping during use, the strength of the window glass used in mobile displays is improved using ion exchange chemical strengthening.

[0005] For example, Korean Patent Publication No. 10-1999-0042313 discloses a method for strengthening display glass.

[0006] However, despite this chemical strengthening treatment, ultra-thin glass is still too thin, so a protective film is attached with a soft adhesive to prevent shattering, etc. However, this weakens the pencil hardness, causing problems such as leaving marks when using a pen.

[0007] Alternatively, when a resin coating layer is formed on the ultra-thin glass to prevent scattering or improve surface hardness, shrinkage stress caused by hardening of the coating layer can cause curling, resulting in a problem of reduced processability.

[0008] Furthermore, even if a coating layer is formed on the ultra-thin glass, the side surfaces cannot be protected, and if an external impact is applied to the side surfaces during the manufacturing process, the glass substrate is prone to cracking, causing glass fragments to scatter. Summary of the Invention [Problem to be solved by the invention]

[0009] An object of the present invention is to provide an optical laminate of a glass substrate that not only has excellent pencil hardness characteristics and can ensure flex resistance, and is easy to process because it does not curl, but also prevents the glass substrate from breaking due to external impact and, even if it does break, prevents glass fragments from scattering.

[0010] Another object of the present invention is to provide an image display device including the optical laminate. [Means for solving the problem]

[0011] On the other hand, the present invention Glass substrate, a primer layer formed on the glass substrate so as to cover the top and side surfaces of the glass substrate; a base resin layer formed on the primer layer so as to cover the top and side surfaces of the primer layer; and An optical laminate comprising a functional coating layer formed on the base resin layer, The glass substrate is an ultra-thin glass having a thickness of less than 100 μm, The pencil hardness of the entire optical laminate is 2H or more, An optical laminate that satisfies the following mathematical formula 1 is provided. [Mathematical formula 1] 0.1≦d2 / d1≦0.4 In the above formula, d1 is the thickness of the glass substrate, and d2 is the total thickness of the primer layer, the substrate resin layer, and the functional coating layer.

[0012] In one embodiment of the present invention, the primer layer may be formed to cover the entire surface of the glass substrate.

[0013] In one embodiment of the present invention, the base resin layer may be formed so as to cover the entire surface of the primer layer.

[0014] The optical laminate according to one embodiment of the present invention may have a total thickness of less than 120 μm.

[0015] In an embodiment of the present invention, the primer layer may be formed from a primer layer-forming composition including one or more resins selected from the group consisting of polyurethane resin and polyester resin.

[0016] In one embodiment of the present invention, the primer layer may be formed from a primer layer-forming composition including a water-based polyurethane resin and a stabilizer, and the stabilizer may include a primary heat stabilizer and a secondary heat stabilizer.

[0017] In one embodiment of the present invention, the primary heat stabilizer may be at least one selected from a phenol-based heat stabilizer and an amine-based heat stabilizer, and the secondary heat stabilizer may be at least one selected from a phosphorus-based heat stabilizer and a sulfur-based heat stabilizer.

[0018] In an embodiment of the present invention, the base resin layer may be formed from a composition for forming a base resin layer including at least one resin selected from the group consisting of a polyimide resin and a polyamide-imide resin.

[0019] In one embodiment of the present invention, the base resin layer may have an elastic modulus of 3.3 to 5.2 GPa.

[0020] In one embodiment of the present invention, the functional coating layer may be a hard coating layer.

[0021] In one embodiment of the present invention, the hard coating layer may be formed from a hard coating composition including a light-transmitting resin, a fluorine-based UV-curable functional group-containing compound, a photoinitiator, and a solvent.

[0022] On the other hand, the present invention provides an image display device including the optical laminate.

[0023] On the other hand, the present invention provides a window for a flexible display device including the optical laminate.

[0024] On the other hand, the present invention provides a polarizing plate including the optical laminate.

[0025] On the other hand, the present invention provides a touch sensor including the optical laminate.

[0026] On the other hand, the present invention provides a variable transmittance optical laminate including the optical laminate.

[0027] On the other hand, the present invention provides a smart window including the variable transmittance optical stack. [Effects of the Invention]

[0028] The optical laminate according to one embodiment of the present invention protects the sides of the glass substrate, preventing it from breaking due to external impact and preventing glass fragments from scattering even if it does break. Furthermore, the optical laminate according to the present invention has a structure in which a primer layer, a substrate resin layer, and a functional coating layer are sequentially laminated on an ultra-thin glass substrate such that the ratio of the total thickness of the primer layer, substrate resin layer, and functional coating layer to the thickness of the glass substrate is controlled within a specific range. This structure provides excellent pencil hardness and flex resistance, and is easy to process because it does not curl. In particular, the optical laminate according to one embodiment of the present invention has a pencil hardness of 2H or more, and does not leave marks when using a pen. [Brief explanation of the drawings]

[0029] [Figure 1] 1 is a schematic cross-sectional view of an optical laminate according to one embodiment of the present invention. [Figure 2] 1 is a schematic cross-sectional view of an optical laminate according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0030] The present invention will now be described in more detail.

[0031] One embodiment of the present invention comprises: Glass substrate, a primer layer formed on the glass substrate so as to cover the top and side surfaces of the glass substrate; a base resin layer formed on the primer layer so as to cover the upper and side surfaces of the primer layer; and An optical laminate comprising a functional coating layer formed on the base resin layer, The glass substrate is an ultra-thin glass having a thickness of less than 100 μm, The pencil hardness of the entire optical laminate is 2H or more, The optical laminate satisfies the following mathematical formula 1. [Mathematical formula 1] 0.1≦d2 / d1≦0.4 In the above formula, d1 is the thickness of the glass substrate, and d2 is the total thickness of the primer layer, the substrate resin layer, and the functional coating layer.

[0032] In the optical layered body according to one embodiment of the present invention, the value of d2 / d1 is 0.1 to 0.4, and preferably 0.1 or more and less than 0.3.

[0033] In the present invention, d1 is the thickness of the glass substrate, and d2 is the total thickness of the primer layer, the substrate resin layer, and the functional coating layer.

[0034] Specifically, in the case of a structure in which a primer layer is formed on a glass substrate so as to cover only the upper and side surfaces of the glass substrate, and a substrate resin layer is formed on the primer layer so as to cover only the upper and side surfaces of the primer layer, d2 is the total thickness of the primer layer, substrate resin layer, and functional coating layer present on the upper surface of the glass substrate.

[0035] In addition, in the case of a structure in which a primer layer is formed on a glass substrate so as to cover the entire surface of the glass substrate, and a substrate resin layer is formed on the primer layer so as to cover the entire surface of the primer layer, d2 is the sum of the total thickness of the primer layer, substrate resin layer, and functional coating layer present on the upper surface of the glass substrate and the total thickness of the primer layer and substrate resin layer present on the lower surface of the glass substrate.

[0036] If the value of d2 / d1 is less than 0.1, the hardness may be reduced to such an extent that the lower glass substrate may crack during pencil hardness measurement, and if the value of d2 / d1 is more than 0.4, the curling properties may be poor.

[0037] In an optical laminate according to one embodiment of the present invention, the pencil hardness of the entire optical laminate is 2H or more, preferably 4H or more.

[0038] The pencil hardness is measured by fixing the optical laminate with the functional coating layer facing up, and then repeatedly performing a pencil hardness test on the surface of the functional coating layer at a length of 1 cm under a load of 750 gf five times. If no visual abnormalities such as scratches are observed four or more times during the test, the hardness of the pencil used in the test is taken as the pencil hardness. For example, if five test operations are performed using a 2H pencil and no visual abnormalities are observed four or more times, the pencil hardness of the material is 2H or higher.

[0039] If the pencil hardness of the entire optical laminate is less than 2H, an indentation may remain when using a pen, and it may take a long time for the indentation to recover.

[0040] The optical laminate according to one embodiment of the present invention may have a total thickness of less than 120 μm, for example, 35 μm or more and less than 120 μm. If the total thickness of the optical laminate is 120 μm or more, it may be difficult to ensure bending resistance.

[0041] An optical laminate according to one embodiment of the present invention has a structure in which a primer layer is formed on a glass substrate so as to cover the upper and side surfaces of the glass substrate, and a substrate resin layer is formed on the primer layer so as to cover the upper and side surfaces of the primer layer. This structure prevents the glass substrate from breaking due to external impact, particularly external impact applied to the side surfaces of the glass substrate, and even if the glass substrate breaks, it can prevent glass fragments from scattering.

[0042] Furthermore, the optical laminate according to one embodiment of the present invention has a structure in which a primer layer, a substrate resin layer, and a functional coating layer are sequentially laminated on a glass substrate, which is an ultra-thin glass, such that the ratio of the total thickness of the primer layer, substrate resin layer, and functional coating layer to the thickness of the glass substrate is controlled within a specific range. This structure provides excellent pencil hardness and ensures bending resistance, and is easy to process because curling does not occur. In particular, the optical laminate according to one embodiment of the present invention has a pencil hardness of 2H or more, which means that no marks are left when using a pen. Furthermore, the optical laminate according to one embodiment of the present invention can ensure bending even with a curvature radius of 3 mm. Furthermore, the optical laminate according to one embodiment of the present invention exhibits antifouling properties, abrasion resistance, and chemical resistance.

[0043] 1 and 2 are cross-sectional views of the structure of an optical laminate according to one embodiment of the present invention.

[0044] Referring to FIG. 1, an optical laminate 100 according to one embodiment of the present invention includes a glass substrate 110, a primer layer 120, a substrate resin layer 130, and a functional coating layer 140, which are sequentially laminated, wherein the primer layer 120 is formed on the glass substrate 110 to cover the top and side surfaces of the glass substrate 110, and the substrate resin layer 130 is formed on the primer layer 120 to cover the top and side surfaces of the primer layer 120.

[0045] Referring to FIG. 2, an optical laminate 100 according to one embodiment of the present invention includes a glass substrate 110, a primer layer 120, a substrate resin layer 130, and a functional coating layer 140, which are sequentially laminated, with the primer layer 120 being formed to cover the entire surface of the glass substrate 110, and the substrate resin layer 130 being formed to cover the entire surface of the primer layer 120.

[0046] Each component of the optical laminate will be described in detail below.

[0047] The glass substrate 110 is made of ultra-thin glass (UTG) having a thickness of less than 100 μm. For example, the thickness of the glass substrate 110 is 10 μm or more and less than 100 μm, preferably 20 to 95 μm, and more preferably 30 to 90 μm.

[0048] If the thickness of the glass substrate is 100 μm or more, the bending resistance may decrease.

[0049] The ultra-thin glass may contain one or more selected from the group consisting of aluminoborosilicate, borosilicate, alkali lead silicate, soda lime, lithium aluminosilicate, and aluminosilicate, and preferably contains one or more selected from the group consisting of soda lime, lithium aluminosilicate, and aluminosilicate.

[0050] The ultra-thin glass is obtained by cutting a substrate into cells, and the cut surfaces, i.e., the side surfaces of the ultra-thin glass, may be vertical and free of bending, and may be polished to have a uniform side roughness. The polished ultra-thin glass may have an edge portion where the top surface and the side surface are connected by the polished portion. The edge portion may be inclined or curved.

[0051] The ultra-thin glass may be manufactured by the manufacturing method described below, but is not limited thereto.

[0052] The method for manufacturing the ultra-thin glass may include the steps of cutting an original glass sheet into cells; polishing the cut surfaces of the cells; etching the polished cells; and healing the polished cut surfaces of the cells.

[0053] Furthermore, the method for manufacturing ultra-thin glass may further include, after the healing step, a cleaning step; a chemical strengthening step; and / or a chemical polishing step.

[0054] The step of cutting the original glass into cells First, a plurality of cells are prepared by cutting an original glass plate into cells.

[0055] The step of cutting the original glass sheet into cells is a step for forming a shape according to the design of the device in which the original glass sheet is to be used, and may involve cutting the original glass sheet into a plurality of cells. This step may be performed without laminating the original glass sheet into a plurality of layers. This has the advantages of enabling tracking of cells in the event of a defect, simplifying the manufacturing process by omitting the lamination step, reducing the defect rate due to residue that may be generated during the lamination step, and allowing for flexible selection of the shape of the glass side surface.

[0056] The cutting step is not particularly limited as long as it can cut the original plate glass to form a plurality of cells. In one embodiment, the cutting step may be performed by using a diamond cutting wheel or a CNC cutter equipped with a laser to form a plurality of cells having a predetermined shape.

[0057] Polishing the cut surface of the unit cell Next, the method for manufacturing the ultra-thin glass includes a step of polishing the cut surfaces of the cells.

[0058] The polishing is preferably physical polishing, and most preferably physical polishing so that the cut surfaces of the cells are rounded. The cut surfaces of the cells refer to the side surfaces of the cells. In this case, the thickness of the cut cells may be the same as the thickness of the original plate glass.

[0059] The physical polishing includes physically polishing chipping on the cut surface after the cutting step and simultaneously processing the side surfaces of the cells into a desired shape, and the thickness of the cut cells may be the same as the thickness of the original glass sheet before cutting.

[0060] The polished cut surface, i.e., the side surface of the cell, may be gently rounded with a predetermined curvature from the viewpoint of stability, which reduces the possibility of breakage during subsequent processes.

[0061] The physical polishing step is not particularly limited as long as it can physically polish away chipping that occurs during cutting. In one embodiment, the physical polishing step may include a rough grinding step of grinding the cut surfaces of the cut cells using a chamfering tool of 400 mesh or less; a medium grinding step of grinding the cut surfaces of the cells that have undergone the rough grinding step using a chamfering tool of about 500 to 800 mesh; and a finish grinding step of grinding the cross sections of the cells that have undergone the medium grinding step using a chamfering tool of 1200 mesh or more.

[0062] Etching of the polished cell and healing step of the polished cut surface of the polished cell Then, the method may include etching the polished cell and healing the polished cut surface of the polished cell, which may include simultaneously performing etching the polished cell and healing the polished cut surface of the polished cell. The healed cut surface refers to the side surface of the final ultra-thin glass cell.

[0063] In the healing step, the polished cells may be etched without a protective material, such as a resin or film, to prevent impact on the glass during the process or to mask it against the etching solution.

[0064] The polished cell may be ultra-thinned by a chemical etching process, and the polished cut surface of the cell may be healed to obtain an ultra-thin glass in cell units.

[0065] Specifically, the polished cell etching step may include, but is not limited to, chemical etching, and the polished cell etching step may result in ultra-thinning of the cell.

[0066] The ultra-thinning refers to a process of thinning glass to a thickness of less than 100 μm.

[0067] The etching of the polished cells and the healing step of the polished cut surface of the polished cells may be performed separately, but it is more preferable from the viewpoint of process simplification that the healing step of the polished cell cut surface is performed simultaneously and in the same manner as the etching step of the polished cells.

[0068] When the etching and healing steps are performed simultaneously, thick cells can be ultra-thinned and the cut surfaces can be smoothly rounded. The healing step may be performed to improve the strength of the edges of the cut cells, and the healed cut surfaces may be smoother and more rounded than the polished cut surfaces. Defects such as chipping on the cut surfaces caused by physical polishing are removed by healing, and roughness is reduced, thereby preventing breakage due to bending. The rounded surfaces preferably have a gentle curve.

[0069] The chemical etching step may be performed by dipping the cell into an etching solution. In one embodiment, the chemical etching step may include one or more of: a cell jig fixing step of fixing the cell to a jig for handling the cell; a jig immersion step of immersing the jig in an etching solution bath filled with the etching solution so that the cell can be immersed in the etching solution; a chemical etching step of uniformly chemically etching the thickness and cut surface at a constant etching rate while the jig is immersed; a jig removal step of removing the jig from the etching solution bath when the chemical etching is completed; and a cell separation step of separating the chemically etched cell from the jig.

[0070] In addition to the immersion method in which the cells are completely immersed in the etching solution, side spray or top spray methods can be used to assist etching. Etching can also be performed using only the side spray or top spray method, without using the immersion method in which the cells are completely immersed in the etching solution. In this case, the glass is cut into cells, and the surface tension of the sprayed etching solution allows the etching solution to adhere to the surface of the glass cells, enabling both etching and side healing.

[0071] In the etching and healing steps, the etching and healing are performed while the glass cells are moved by upper and lower jigs, respectively, so that contact between the glass cells can be minimized.

[0072] In one or more embodiments, the etching solution may include one or more selected from the group consisting of hydrofluoric acid (HF), ammonium fluoride (NHF), ammonium hydrogen fluoride (NHHF), sodium fluoride (NaF), sodium hydrogen fluoride (NaHF), lithium fluoride (LiF), potassium fluoride (KF), calcium fluoride (CaF), and the like.

[0073] When the etching of the polished cells and the healing step of the polished cut surfaces of the polished cells are performed in separate steps, the cells may be etched by the chemical etching step as described above, and then a healing step of the polished cut surfaces of the polished cells may be further performed using the same method as the chemical etching step described above.

[0074] Cleaning, chemical strengthening and / or chemical polishing steps The method for manufacturing the ultra-thin glass may further include a cleaning step, a chemical strengthening step, and / or a chemical polishing step, and the cleaning step, the chemical strengthening step, and the chemical polishing step may be changed in order, added, or omitted as necessary.

[0075] The cleaning step may be for removing residual foreign matter or etching solution from a previous process. A commonly used cleaning process for removing residual foreign matter or etching solution may be used. In one embodiment, the cleaning process may be performed using a water cleaning solution. The cleaning process may be performed by spraying the water cleaning solution or by dipping the substrate in the water cleaning solution.

[0076] The washing liquid is not particularly limited as long as it can clean the surface of the ultra-thin glass. In one or more embodiments, it may be pure water (DI water) or an alkaline washing liquid containing potassium hydroxide (KOH) or sodium hydroxide (NaOH).

[0077] The chemical strengthening step strengthens the ultra-thin glass by immersing the ultra-thin glass in molten salt and exchanging alkali ions in the ultra-thin glass with alkali ions in the molten salt. In one embodiment, the chemical strengthening step may include a preheating step of gradually increasing the temperature of the ultra-thin glass; a chemical strengthening step of chemically strengthening the preheated ultra-thin glass by ion exchange; and a slow cooling step of the strengthened ultra-thin glass at room temperature.

[0078] The preheating step of gradually increasing the temperature of the ultra-thin glass may be performed to gradually increase the temperature before immersing the ultra-thin glass in the ion exchange solution in order to prevent breakage of the ultra-thin glass due to a sudden temperature change in the chemical strengthening step, which is performed at a high temperature of 350 to 500°C.

[0079] The chemical strengthening step is Na + Glass containing K + When exposed to a salt containing ions, the surface Na + and K. + The ion exchange proceeds inward, in this case Na in the ultra-thin glass structure. + K is placed in the position previously occupied by + Ions enter, Na+ than the ionic radius of + Since the ionic radius of the glass is large, a compressive force is generated around the network structure, which may strengthen the glass.

[0080] Chemical strengthening by K + The depth to which ions are exchanged is not particularly limited, but from the viewpoint of improving bending resistance, it may be a depth of 5% to 40% of the cell thickness, and specifically, it is preferably 10% to 35%, and more preferably 15% to 30%.

[0081] Furthermore, the targeted depth of chemical strengthening may vary depending on the thickness of the glass. For example, as shown in Table 1 below, the depth (thickness) of chemical strengthening may vary depending on the thickness of the glass.

[0082] [Table 1]

[0083] The ion exchange solution used for the chemical strengthening may be a commonly used ion exchange solution. In one embodiment, the ion exchange solution may contain potassium nitrate (KNO).

[0084] After the chemical strengthening process, a cooling step and a process for removing impurities may be further performed. The cooling and impurity removal processes may be conventional processes. In one embodiment, after the natural cooling process by contacting with the outside air, a washing process may be included to remove impurities, such as potassium nitrate.

[0085] The chemical polishing step involves polishing the ultra-thin glass with a chemical polishing solution. From the perspective of improving bending resistance, the thickness of the ultra-thin glass after chemical polishing may be polished to 80% or more and less than 100%, preferably 90% or more and less than 100%, of the thickness of the ultra-thin glass before chemical polishing.

[0086] The chemical polishing solution is not particularly limited as long as it is a solution commonly used in the process of polishing ultra-thin glass, and may include at least one of hydrofluoric acid (HF) and ammonium fluoride (NHF).

[0087] Furthermore, after the chemical polishing step, a cleaning step may be further carried out as necessary.

[0088] The primer layer 120 is formed to cover the upper and side surfaces of the glass substrate 110. Alternatively, the primer layer 120 is formed to cover the entire surface of the glass substrate 110.

[0089] The primer layer 120 serves to further improve the adhesion between the glass substrate 110 and the substrate resin layer 130 .

[0090] In one embodiment of the present invention, the primer layer 120 may be formed from a primer layer-forming composition including one or more resins selected from the group consisting of polyurethane resin and polyester resin, and preferably from a primer layer-forming composition including polyurethane resin.

[0091] In particular, the primer layer may include a water-based polyurethane resin and a stabilizer to prevent yellowing even under high temperature or ultraviolet light conditions and improve hardness and flex resistance, and the stabilizer may be formed from a primer layer-forming composition including a primary heat stabilizer and a secondary heat stabilizer.

[0092] The water-based polyurethane resin has the advantage of being superior in optical properties and adhesion compared to common solvent-based polyurethane resins.

[0093] The water-based polyurethane resin includes ionic resins and non-ionic resins. Non-ionic resins have good particle stability but are inferior to water-based polyurethane resins having ionic functional groups in mechanical properties such as film-forming ability and adhesive strength. Therefore, it is preferable to use water-based polyurethane resins having ionic functional groups in order to maintain mechanical properties.

[0094] The aqueous polyurethane resin may be prepared by a prepolymer process using polyester polyol, diisocyanate, and a chain extender as raw materials. Specifically, the aqueous polyurethane resin is synthesized by mixing polyester polyol and diisocyanate and reacting them at high temperature to prepare a prepolymer, adding the prepolymer to water under high-speed stirring to disperse it, and then adding a chain extender to polymerize the dispersed prepolymer to adjust the molecular weight.

[0095] In addition, when producing a water-based polyurethane resin having ionic functional groups, a dispersant (ionizing agent) is further added to a polyester polyol and a diisocyanate, and the mixture is reacted at high temperature to produce a hydrophilic prepolymer. Then, a neutralizing agent is added to neutralize the hydrophilic prepolymer, and the neutralized hydrophilic prepolymer is dispersed in water under high-speed stirring. A chain extender is then added to adjust the molecular weight through a polymerization reaction of the dispersed hydrophilic prepolymer, thereby synthesizing the water-based polyurethane resin.

[0096] Specifically, the water-based polyurethane resin uses polycaprolactone polyol, a type of polyester polyol, to overcome the drawback of being hydrolyzed by water, and has the advantage of being resistant to decomposition even at high temperatures and humidity, while the use of isophorone diisocyanate, an aliphatic diisocyanate, allows it to exhibit transparency compared to aromatic diisocyanates.

[0097] The aqueous polyurethane resin does not contain fluorine atoms, and therefore can maintain an appropriate surface energy and provide adhesion to the film. Furthermore, since the aqueous polyurethane resin does not contain sulfo groups, it can exhibit better optical properties by suppressing the generation of haze.

[0098] The number average molecular weight of the aqueous polyurethane resin may be 10,000 to 4,000,000, and preferably 20,000 to 2,000,000. When the number average molecular weight is within this range, stability in an aqueous dispersion state can be ensured, and the resin has excellent coating properties and good mechanical properties.

[0099] The aqueous polyurethane resin may be contained in an amount of 1 to 40 wt % based on 100 wt % of the total composition for forming a primer layer, but is not limited thereto. When the aqueous polyurethane resin is contained in this content range, excellent adhesion between the glass substrate and the substrate resin layer and coatability can be ensured.

[0100] The stabilizers include a primary heat stabilizer and a secondary heat stabilizer.

[0101] The stabilizer contains a combination of a primary heat stabilizer and a secondary heat stabilizer, which scavenges radicals generated by heat or UV light and inhibits further decomposition reactions, thereby preventing yellowing even under high temperature or UV light conditions.

[0102] Specifically, by using a combination of a primary heat stabilizer and a secondary heat stabilizer as the stabilizer, the film can maintain its transparency without yellowing even after high-temperature heat treatment at 100 to 250°C for 20 to 60 minutes.

[0103] Therefore, the primer layer 120 does not yellow even after high-temperature heat treatment performed when forming the base resin layer 130, which will be described later, and can maintain its transparency.

[0104] For example, after a laminate in which a primer layer 120 is formed on a glass substrate 110 is heat-treated at 100 to 250°C for 20 to 60 minutes, the yellow index (YI) of the laminate according to ASTM E313-73 may be less than 1.0.

[0105] The primary heat stabilizer acts to stabilize radicals by releasing hydrogen to prevent radical chain reactions when a polymer material reacts with oxygen due to heat or ultraviolet light, thereby preventing yellowing through its radical scavenging function.

[0106] The primary heat stabilizer may be at least one selected from the group consisting of phenol-based heat stabilizers and amine-based heat stabilizers.

[0107] Examples of the phenol-based heat stabilizer include 3,9-bis[2-[3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy]-1,1-dimethylethoxy]-2,4,8,10-tetraoxaspiro[5.5]undecane, pentaerythrityl-tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], 1,3,5-trimethyl-2,4,6-tris(3'5'-di-t-butyl-4-hydroxybenzyl)benzene, triethylene glycol-bis[3-(3-t-butyl-5-methyl-4-hydroxyphenyl)propionate], 4,4'-thiobis(6-t-butyl-3-methylphenol), tris-(3,5-di-t-butyl-4-hydroxybenzyl)-isocyanurate, ester, 1,3,5-tris(4-t-butyl-3-hydroxy-2,6-dimethylbenzyl)isocyanurate, 1,6-hexanediol-bis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], 2,2-thio-diethylenebis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], N,N'-hexamethylenebis(3,5-di-t-butyl-4-hydroxy-hydrocinnamic acid amide), 1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene, 2,4-bis[(octylthio)methyl]-O-cresol, 1,6-hexanediol-bis-[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], octadecyl Examples include 3-(3,5-di-tert-butyl-4-hydroxyphenol)propionate, 2,2'-methylenebis(4-methyl-6-t-butylphenol), 4,4'-butylidene-bis(3-methyl-6-t-butylphenol), 1,1,3-tris(2-methyl-4-hydroxy-5-t-butylphenyl)butane, 1,3,5-tris(4-hydroxybenzyl)benzene, and tetrakis[methylene-3-(3,5'-di-t-butyl-4'-hydroxyphenylpropionate)]methane.

[0108] Commercially available phenolic heat stabilizers include Irganox 1010 (manufactured by BASF), Sumilizer BBM-S (manufactured by Sumitomo Chemical Co., Ltd.), ADK STAB AO-80 (manufactured by Adeka Corporation), Sumilizer GP (manufactured by Sumitomo Chemical Co., Ltd.), and Irganox 1035 (manufactured by BASF).

[0109] Examples of the amine-based heat stabilizer include naphthylamine-based heat stabilizers such as 1-naphthylamine, phenyl-1-naphthylamine, p-octylphenyl-1-naphthylamine, p-nonylphenyl-1-naphthylamine, p-dodecylphenyl-1-naphthylamine, and phenyl-2-naphthylamine; N,N'-diisopropyl-p-phenylenediamine, N,N'-diisobutyl-p-phenylenediamine, N,N'-diphenyl-p-phenylenediamine, N,N'-di-β-naphthyl-p-phenylenediamine, N-phenyl-N'-isopropyl-p-phenylenediamine, N-cyclohexyl-N'-phenyl-p-phenylenediamine, N-1,3-dimethylbutyl-N'-phenyl-p-phenylenediamine, dioctyl-p-phenylenediamine, phenylhexyl-p-phenylenediamine, and phenyloctyl-p-phenylenediamine. phenylenediamine-based heat stabilizers such as; diphenylamine-based heat stabilizers such as dipyridylamine, diphenylamine, p,p'-di-n-butyldiphenylamine, p,p'-di-t-butyldiphenylamine, p,p'-di-t-pentyldiphenylamine, p,p'-dioctyldiphenylamine, p,p'-dinonyldiphenylamine, p,p'-didecyldiphenylamine, p,p'-didodecyldiphenylamine, p,p'-distyryldiphenylamine, p,p'-dimethoxydiphenylamine, 4,4'-bis(4-α,α-dimethylbenzoyl)diphenylamine, p-isopropoxydiphenylamine, and dipyridylamine; and phenothiazine-based heat stabilizers such as phenothiazine, N-methylphenothiazine, N-ethylphenothiazine, 3,7-dioctylphenothiazine, phenothiazine carboxylic acid ester, and phenoselenazine.

[0110] The secondary heat stabilizer reduces peroxides generated by radicals during the decomposition reaction, thereby suppressing the generation of peroxide radicals. When used together with the primary heat stabilizer, a synergistic effect is achieved, imparting high-temperature resistance and preventing coloration and yellowing.

[0111] The secondary heat stabilizer may be at least one selected from a phosphorus-based heat stabilizer and a sulfur-based heat stabilizer.

[0112] Examples of the phosphorus-based heat stabilizer include 3,9-bis(2,6-di-tert-butyl-4-methylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane, diisodecylpentaerythritol diphosphite, bis(2,4-di-t-butylphenyl)pentaerythritol diphosphite, 2,2'-methylenebis(4,6-di-t-butyl-1-phenyloxy)(2-ethylhexyloxy)phosphorus, 6-[3-(3 -t-butyl-4-hydroxy-5-methylphenyl)propoxy]-2,4,8,10-tetra-t-butyldibenz[d,f][1,3,2]dioxaphosphepine, triphenyl phosphite, diphenyl isodecyl phosphite, phenyl diisodecyl phosphite, 4,4'-butylidene-bis(3-methyl-6-t-butylphenylditridecyl) phosphite, octadecyl phosphite, tris(nonylphenyl) phosphite, 9,10-dihydro-9-o 10-(3,5-di-t-butyl-4-hydroxybenzyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10-(3,5-di-t-butyl-4-hydroxybenzyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10-decyloxy-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, tris(2,4-di-t-butylphenyl)phosphite, cyclic neopentanetetraylbis(2,4-di-t-butylphenyl)phosphite phosphate, cyclic neopentanetetraylbis(2,6-di-t-butylphenyl)phosphite, 2,2-methylenebis(4,6-di-t-butylphenyl)octylphosphite, tris(2,4-di-t-butylphenyl)phosphite, tetrakis(2,4-di-t-butylphenyl)[1,1-biphenyl]-4,4'-diylbisphosphonite, bis[2,4-bis(1,1-dimethylethyl)-6-methylphenyl]ethyl ester phosphonic acid, and the like.

[0113] Commercially available phosphorus-based heat stabilizers include ADK STAB 1178, ADK STAB TPP, ADK STAB 1500, ADK STAB 135A, and ADK STAB 517 manufactured by Adeka Corporation, Sumilizer GP manufactured by Sumitomo Chemical Co., Ltd., and Irganox 1035 manufactured by BASF.

[0114] Examples of the sulfur-based heat stabilizer include 2,2-bis({[3-(dodecylthio)propionyl]oxy}methyl)-1,3-propanediyl-bis[3-(dodecylthio)propionate], 2-mercaptobenzimidazole, dilauryl-3,3′-thiodipropionate, dimyristyl-3,3′-thiodipropionate, distearyl-3,3′-thiodipropionate, pentaerythrityl-tetrakis(3-laurylthiopropionate), and 2-mercaptobenzimidazole.

[0115] The stabilizer may be included in an amount of 0.1 to 10 wt % based on 100 wt % of the total composition for forming a primer layer, but is not limited thereto. When the stabilizer is included in this content range, it has the advantage of preventing the surface of the cured coating film from being decomposed by heat or ultraviolet light without reducing optical performance, and not affecting curability during thermal curing.

[0116] The primer layer-forming composition of the present invention may further contain a leveling agent.

[0117] The leveling agent is added to improve the smoothness and coatability of the coating film when the composition is applied, and may include one or more of a silicone-based leveling agent, a fluorine-based leveling agent, and an acrylic-based leveling agent.

[0118] Specific examples of the leveling agent include BYK-306, BYK-307, BYK-323, BYK-331, BYK-333, BYK-337, BYK-373, BYK-375, BYK-377, BYK-378, BYK-3530, BYK-3560, BYK-358N, and BYK-361N manufactured by BYK-Chemie, and TEGO Glide 410, TEGO Glide 411, TEGO Glide 415, TEGO Glide 420, TEGO Glide 432, TEGO Glide 435, TEGO Glide 440, TEGO Glide 450, TEGO Glide 455, TEGO Rad 2100, TEGO Rad 2200N, TEGO Rad 2250, and TEGO Rad 2300 manufactured by Degussa. 2300, TEGO Rad 2500, FC-4430 and FC-4432 manufactured by 3M may be used, but are not limited to these.

[0119] The leveling agent may be included in an amount of 0.01 to 1 wt % based on 100 wt % of the total composition for forming a primer layer, but is not limited thereto. When the leveling agent is included in the above content range, it has the advantage of maximizing the smoothness and coatability of the coating film and maintaining excellent hardness and flexibility.

[0120] The primer layer-forming composition of the present invention may further contain a solvent.

[0121] The solvent may be any solvent that can dissolve or disperse the above-mentioned components without any particular limitation.

[0122] Usable solvents include alcohols (methanol, ethanol, isopropanol, butanol, methyl cellosolve, ethyl cellosolve, etc.), ketones (methyl ethyl ketone, methyl butyl ketone, methyl isobutyl ketone, diethyl ketone, dipropyl ketone, cyclohexanone, etc.), acetates (ethyl acetate, propyl acetate, n-butyl acetate, tert-butyl acetate, methyl cellosolve acetate, ethyl cellosolve acetate, propylene glycol monomethyl ether acetate, propylene glycol Preferred solvents include glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, methoxybutyl acetate, methoxypentyl acetate, etc., hexanes (hexane, heptane, octane, etc.), benzenes (benzene, toluene, xylene, etc.), and ethers (diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dipropyl ether, diethylene glycol dibutyl ether, propylene glycol monomethyl ether, etc.). The solvents exemplified above may be used alone or in combination of two or more.

[0123] The solvent may be included as the remainder so that the total weight of the primer layer-forming composition is 100%. For example, the solvent may be used in an amount of 50 to 98% by weight based on 100% by weight of the total primer layer-forming composition. If the solvent content is less than this range, the viscosity will be high, making workability poor, and the thickness of the coating layer cannot be reduced, which may result in reduced flexibility. Conversely, if the solvent content exceeds this range, the desired coating thickness will not be achieved, and the coating liquid may run off during the drying process, contaminating the opposite side of the glass or film and causing spots.

[0124] The primer layer 120 may be formed by applying the above-described primer layer-forming composition onto the glass substrate 110 and curing it.

[0125] The coating may be carried out using a known method such as a slit coating method, a knife coating method, a spin coating method, a casting method, a microgravure coating method, a gravure coating method, a bar coating method, a roll coating method, a wire bar coating method, a dip coating method, a spray coating method, a screen printing method, a gravure printing method, a flexographic printing method, an offset printing method, an inkjet coating method, a dispenser printing method, a nozzle coating method, or a capillary coating method.

[0126] For example, the application of the primer layer-forming composition to the side surfaces of the glass substrate 110 may be performed by standing the glass substrate 110 and dipping all four side surfaces of the glass substrate 110 into the primer layer-forming composition by 3 mm or less, for example, about 1 mm. The application of the primer layer-forming composition to the upper and / or lower surfaces of the glass substrate 110 may be performed by slit coating the primer layer-forming composition onto the upper and / or lower surfaces of the glass substrate 110.

[0127] The curing may be performed by a thermal curing process of pre-bake and / or post-bake. The thermal curing process may be performed by a known method, and is preferably performed in an oven at 80 to 150°C for 1 to 5 minutes.

[0128] The primer layer may be formed by further adding a photo-curing oligomer and / or monomer and a photoinitiator to further proceed with the photo-curing process. In the case of photo-curing, after drying, the photo-curing dose is 300 to 1000 mJ / cm. 2 It is preferable to form the primer layer by irradiating the substrate with an integrated UV light amount of 1000 times or more.

[0129] The thickness of the primer layer may be 0.1 μm or more and less than 10 μm, preferably 0.1 to 2 μm. A primer layer thickness within this range is advantageous in terms of adhesion to the glass substrate. If the primer layer thickness is less than 0.1 μm, the base resin layer may penetrate into the primer layer when coated onto the primer layer, making it difficult to achieve adhesion. If the primer layer thickness is 10 μm or more, the optical performance may be reduced. When the primer layer is formed so as to cover the entire surface of the glass substrate, the thickness of the primer layer is the sum of the thicknesses of the primer layers present on the top and bottom surfaces of the glass substrate.

[0130] The base resin layer 130 is formed to cover the upper and side surfaces of the primer layer 120. Alternatively, the base resin layer 130 is formed to cover the entire surface of the primer layer 120.

[0131] The base resin layer 130 serves to support the functional coating layer 140, which will be described later, and also serves as a protective layer to prevent the glass substrate 110 from shattering. Furthermore, the base resin layer 130 serves to control the flex resistance, pencil hardness, and curl characteristics of the optical laminate.

[0132] In one embodiment of the present invention, the base resin layer may be formed from a composition for forming a base resin layer including one or more resins selected from the group consisting of a polyimide resin and a polyamide-imide resin, which has excellent durability against repeated bending, making it easier to apply to flexible displays, and can also ensure pencil hardness and curl properties.

[0133] In particular, the base resin layer may be formed from a base resin layer-forming composition containing a polyamideimide resin in terms of flex resistance, pencil hardness, and curling properties.

[0134] In particular, the elastic modulus of the base resin layer is controlled to be 3.3 to 5.2 GPa.

[0135] By controlling the modulus of elasticity of the base resin layer to 3.3 to 5.2 GPa, preferably 3.8 to 5.2 GPa, and more preferably 4.6 to 5.2 GPa, the bending resistance, pencil hardness, and curling properties of the optical laminate can be simultaneously ensured.

[0136] If the elastic modulus of the substrate resin layer exceeds 5.2 GPa, the shrinkage stress proportional to the product of the curl (strain rate) due to shrinkage that occurs when the substrate resin layer dries and the elastic modulus becomes large, and this shrinkage stress may affect the entire module even after lamination of the display module, increasing the tendency for curling toward the functional coating layer.On the other hand, if the elastic modulus is less than 3.3 GPa, the elastic modulus of the substrate resin layer itself is insufficient, reducing resistance to deformation due to external forces and recovery, thereby reducing the pencil hardness of the substrate resin layer itself, which may ultimately lead to a reduction in the pencil hardness of the entire optical laminate.

[0137] The elastic modulus is a value that indicates the rigidity of a material and is also called the modulus of elasticity. The elastic modulus is defined as the ratio of stress to strain in the elastic region, and can be determined from the slope of the linear elastic region in a stress-strain curve obtained by a tensile test on a test piece of the material.

[0138] Specifically, the modulus of elasticity of the substrate resin layer may be measured in tensile evaluation mode using a Universal Testing Machine (UTM). The substrate resin layer may be formed on glass without a primer layer, dried, and then peeled off to obtain only the substrate resin layer. The substrate resin layer thus obtained may be cut using a super cutter according to the JIS-K7139 bar-type standard to prepare a test piece for tensile evaluation, and the modulus of elasticity may be measured in tensile evaluation mode of the Universal Testing Machine at a tensile speed of 4 mm / min.

[0139] The elastic modulus of the base resin layer can be adjusted by controlling the type and molar ratio of repeating units constituting the resin, the weight average molecular weight of the resin, and the like.

[0140] The polyimide resin refers to a resin containing a repeating unit containing an imide group.

[0141] The polyimide resin can be produced by imidizing a polyamic acid obtained by polycondensation of a tetracarboxylic acid compound and a diamine compound. The imidization can be carried out chemically and / or thermally.

[0142] The tetracarboxylic acid compound refers to a tetracarboxylic acid or a tetracarboxylic acid derivative. Examples of the tetracarboxylic acid derivative include anhydrides of tetracarboxylic acids, preferably dianhydrides, and acid chlorides. Examples of the tetracarboxylic acid compound include aromatic tetracarboxylic acids and their anhydrides, preferably dianhydrides, and other aromatic tetracarboxylic acid compounds; and aliphatic tetracarboxylic acids and their anhydrides, preferably dianhydrides, and other aliphatic tetracarboxylic acid compounds. These tetracarboxylic acid compounds may be used alone or in combination of two or more.

[0143] Specific examples of the aromatic tetracarboxylic dianhydride include 4,4'-oxydiphthalic dianhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 2,2',3,3'-benzophenonetetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 2,2',3,3'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-diphenylsulfonetetracarboxylic dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride, 2,2-bis(2,3-dicarboxyphenyl)propane dianhydride, 2,2-bis(3,4-dicarboxyphenoxyphenyl)propane dianhydride, 4,4'-(hexafluoroisopropyl)phenyl 1,2-bis(2,3-dicarboxyphenyl)ethane dianhydride, 1,1-bis(2,3-dicarboxyphenyl)ethane dianhydride, 1,2-bis(3,4-dicarboxyphenyl)ethane dianhydride, 1,1-bis(3,4-dicarboxyphenyl)ethane dianhydride, bis(3,4-dicarboxyphenyl)methane dianhydride, bis(2,3-dicarboxyphenyl)methane dianhydride, 4,4'-(p-phenylenedioxy)diphthalic dianhydride, 4,4'-(m-phenylenedioxy)diphthalic dianhydride, 1,2,4,5-benzenetetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, and the like.

[0144] Examples of the aliphatic tetracarboxylic dianhydride include 1,2,4,5-cyclohexanetetracarboxylic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, dicyclohexyl-3,3',4,4'-tetracarboxylic dianhydride, 1,2,3,4-butanetetracarboxylic dianhydride, and 1,2,3,4-pentanetetracarboxylic dianhydride.

[0145] The diamine compound may be an aliphatic diamine and / or an aromatic diamine.

[0146] Examples of the aliphatic diamine include hexamethylenediamine, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, norbornanediamine, and 4,4'-diaminodicyclohexylmethane.

[0147] Examples of the aromatic diamine include p-phenylenediamine, m-phenylenediamine, 2,4-toluenediamine, m-xylylenediamine, p-xylylenediamine, 1,5-diaminonaphthalene, 2,6-diaminonaphthalene, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylpropane, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfone, 3,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, 1,4-bis(4-aminophenoxy)benzene, and 1,3-bis(4-aminophenoxy)benzene. , bis(4-(4-aminophenoxy)phenyl)sulfone, bis(4-(3-aminophenoxy)phenyl)sulfone, 2,2-bis(4-(4-aminophenoxy)phenyl)propane, 2,2-bis(4-(3-aminophenoxy)phenyl)propane, 2,2'-dimethylbenzidine, 2,2'-bis(trifluoromethyl)benzidine, 4,4'-bis(4-aminophenoxy)biphenyl, 9,9-bis(4-aminophenyl)fluorene, 9,9-bis(4-amino-3-methylphenyl)fluorene, 9,9-bis(4-amino-3-chlorophenyl)fluorene, 9,9-bis(4-amino-3-fluorophenyl)fluorene, and the like.

[0148] The molar ratio of the tetracarboxylic acid compound to the diamine compound may be adjusted so as to control the modulus of elasticity of the base resin layer within the above range.

[0149] The weight-average molecular weight (Mw) of the polyimide resin may be 100,000 to 1,000,000 in terms of standard polystyrene. When the weight-average molecular weight (Mw) of the polyimide resin is within this range, coating properties can be ensured when forming a coating film, and the optical laminate has preferable flex resistance, pencil hardness, and curl properties.

[0150] The polyamide-imide resin refers to a resin containing a repeating unit containing an imide group and a repeating unit containing an amide group.

[0151] The polyamide-imide resin may be prepared by imidizing a polyamic acid obtained by polycondensation of a tetracarboxylic acid compound, a dicarboxylic acid compound, and a diamine compound. The imidization may be carried out chemically and / or thermally.

[0152] The tetracarboxylic acid compound and diamine compound may be the same as those used in the production of the polyimide resin.

[0153] The dicarboxylic acid compound refers to a dicarboxylic acid or a dicarboxylic acid derivative, and examples of the dicarboxylic acid derivative include acid chlorides and esters of the dicarboxylic acid. The dicarboxylic acid compounds may be used alone or in combination of two or more.

[0154] Specific examples of the dicarboxylic acid compound include 2,5-thiopentanedicarboxylic acid, 1,3-cyclobutanedicarboxylic acid, 1,3-cyclopentanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 4,4'-oxybisbenzoic acid, terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 4,4'-biphenyldicarboxylic acid, 3,3'-biphenyldicarboxylic acid, terephthaloyl chloride (TPC), 4,4'-biphenyldicarbonyl chloride (BPDC), and 4,4'-oxybis(benzoyl chloride) (OBBC).

[0155] The molar ratio of the tetracarboxylic acid compound, dicarboxylic acid compound, and diamine compound may be adjusted so as to control the modulus of elasticity of the base resin layer within the above range.

[0156] The weight-average molecular weight (Mw) of the polyamide-imide resin may be 100,000 to 1,000,000 in terms of standard polystyrene. When the weight-average molecular weight (Mw) of the polyamide-imide resin is within this range, coating properties can be ensured when forming a coating film, and the optical laminate has favorable flex resistance, pencil hardness, and curl properties.

[0157] The composition for forming the base resin layer may further contain additives such as an ultraviolet absorber, inorganic particles, a surfactant, and an adhesion improver, as required.

[0158] The composition for forming a base resin layer of the present invention may further contain a solvent.

[0159] The solvent may be any solvent that can dissolve or disperse the above-mentioned components without any particular limitation.

[0160] Usable solvents include alcoholic solvents (methanol, ethanol, isopropanol, butanol, methyl cellosolve, ethyl cellosolve, etc.), nitrogen-containing organic solvents (N-methyl-2-pyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, hexamethylformamide, 1,3-dimethyl-2-imidazolidinone, etc.), dimethyl sulfoxide, γ-butyrolactone, etc. The solvents exemplified above may be used alone or in combination of two or more.

[0161] The solvent may be included as the remainder so that the total weight of the composition for forming a base resin layer is 100%. For example, the solvent may be used in an amount that can adjust the viscosity of the composition to a desired range and ensure coatability.

[0162] The base resin layer 130 may be formed by applying the above-described base resin layer-forming composition onto the primer layer 120 and curing it.

[0163] The coating may be carried out using a known method such as a slit coating method, a knife coating method, a spin coating method, a casting method, a microgravure coating method, a gravure coating method, a bar coating method, a roll coating method, a wire bar coating method, a dip coating method, a spray coating method, a screen printing method, a gravure printing method, a flexographic printing method, an offset printing method, an inkjet coating method, a dispenser printing method, a nozzle coating method, or a capillary coating method.

[0164] The application of the composition for forming a base resin layer to the side and upper surfaces of the primer layer 120 may be performed by applying the composition for forming a base resin layer so as to cover the upper surface of the primer layer 120. Because the primer layer 120 has excellent adhesion, the side and upper surfaces can be simultaneously applied by adjusting the application area to be large so as to cover the upper surface of the primer layer 120. To apply the composition to all of the side, upper, and lower surfaces of the primer layer 120, the side and upper surfaces are first applied as described above, and then the lower surface is applied.

[0165] The curing may be performed by a thermal curing process of pre-baking and / or post-baking. The thermal curing process may be performed by a known method, and may be performed using an oven.

[0166] The pre-baking is preferably carried out at a temperature of 140°C or less, and the post-baking is preferably carried out at a temperature of 200°C or more when the base resin is a polyimide resin, or at a temperature of 150°C or more when the base resin is a polyamideimide resin.

[0167] The thickness of the substrate resin layer may be 3 to 50 μm, preferably 5 to 30 μm, and more preferably 5 to 10 μm in terms of the pencil hardness of the optical laminate. If the thickness of the substrate resin layer is thinner than this range, the protective ability for the glass decreases, making the glass more likely to break during handling. If the thickness of the substrate resin layer is thicker than this range, curling during drying of the substrate resin layer may become a problem. When the substrate resin layer is formed so as to cover the entire surface of the primer layer, the thickness of the substrate resin layer is the sum of the thicknesses of the substrate resin layers present on the top and bottom surfaces of the glass substrate.

[0168] A functional coating layer 140 is formed on the base resin layer 130 .

[0169] The functional coating layer 140 improves surface hardness. It also exhibits antifouling properties, excellent abrasion resistance, and excellent elastic recovery, thereby providing excellent pen-pressure resistance. It also exhibits excellent durability, such as scratch resistance, chemical resistance, and flex resistance. Furthermore, the functional coating layer 140 controls the flex resistance and curl characteristics of the optical laminate.

[0170] The functional coating layer 140 may be a hard coating layer.

[0171] In one embodiment of the present invention, the hard coating layer may be formed from a hard coating composition including a light-transmitting resin, a fluorine-based UV-curable functional group-containing compound, a photoinitiator, and a solvent.

[0172] The light-transmitting resin is a photocurable resin, and the photocurable resin may include, but is not limited to, a photocurable (meth)acrylate oligomer and / or monomer.

[0173] The photocurable (meth)acrylate oligomer may be an epoxy (meth)acrylate, a urethane (meth)acrylate, a polyhedral oligomeric silsesquioxane (meth)acrylate, a dendritic (meth)acrylate, or the like, and is preferably at least one of a urethane (meth)acrylate and a dendritic (meth)acrylate.

[0174] The urethane (meth)acrylate may be produced by reacting a (meth)acrylate having a hydroxy group in the molecule with a compound having an isocyanate group in the presence of a catalyst. Specific examples of the (meth)acrylate having a hydroxy group in the molecule include 2-hydroxyethyl (meth)acrylate, 2-hydroxyisopropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, caprolactone ring-opened hydroxyacrylate, pentaerythritol tri(meth)acrylate, and dipentaerythritol penta(meth)acrylate. 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-cyclohexene diisocyanate, 4,4'-methylenebis(cyclohexyl isocyanate), isophorone diisocyanate, and the like. These include trifunctional isocyanates derived from 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), hexamethylene diisocyanate, and the trimethylolpropane adduct toluene diisocyanate.

[0175] The dendritic (meth)acrylate refers to a (meth)acrylate oligomer having a dendritic structure, and in this case, the "dendritic structure" refers to a shape in which monomers are polymerized while branching radially from one nucleus, spreading radially. The dendritic (meth)acrylate can be used without being limited thereto as long as it has the above-mentioned form.

[0176] As commercially available products of the dendritic (meth)acrylate, Miramer SP1106 manufactured by Miwon Co., Ltd., Viscoat 1000, Viscoat 1020, Viscoat 1080 manufactured by Osaka Organic Chemical Industry Co., Ltd., and the like may be used.

[0177] The monomer may be any commonly used monomer without any particular limitation, and is preferably a monomer having an unsaturated group such as a (meth)acryloyl group, a vinyl group, a styryl group, or an allyl group as a photocurable functional group in the molecule, and among these, a monomer having a (meth)acryloyl group is preferred.

[0178] Specific examples of the monomer having a (meth)acryloyl group may be at least one selected from the group consisting of neopentyl glycol acrylate, 1,6-hexanediol di(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-cyclohexane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, isooctyl (meth)acrylate, isodecyl (meth)acrylate, stearyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, phenoxyethyl (meth)acrylate, and isoborneol (meth)acrylate.

[0179] The photocurable (meth)acrylate oligomers and monomers exemplified above may be used either alone or in combination of two or more.

[0180] The light-transmitting resin may be contained in an amount of 1 to 80 wt % based on 100 wt % of the total hard coating composition. If the content of the light-transmitting resin is less than 1 wt %, it is difficult to achieve a sufficient improvement in hardness, and if it exceeds 80 wt %, there is a problem that curling becomes severe.

[0181] The fluorine-based UV-curable functional group-containing compound is a component that imparts antifouling properties, abrasion resistance, and chemical resistance. The fluorine-based UV-curable functional group-containing compound is not particularly limited as long as it contains fluorine and a UV-curable functional group and can chemically bond with the light-transmitting resin that forms the matrix of the hard coating layer.

[0182] The fluorine-based UV-curable functional group-containing compound may be at least one selected from the group consisting of perfluoroalkyl group-containing (meth)acrylates, perfluoropolyether group-containing (meth)acrylates, perfluoroaliphatic group-containing (meth)acrylates, and perfluoroaromatic group-containing (meth)acrylates. In this case, the compound has the advantage of exhibiting excellent antifouling properties and forming a chemical bond with the hard coating layer, thereby maintaining the antifouling properties for a long period of time even after repeated use, which is preferable.

[0183] The fluorine-based UV-curable functional group-containing compound preferably has 1 to 6 UV-curable functional groups.

[0184] Examples of the fluorine-based UV-curable functional group-containing compound include 2,2,2-trifluoroethyl acrylate, 2,2,3,3,3-pentafluoropropyl acrylate, 2-perfluorobutylethyl acrylate, 3-perfluorobutyl-2-hydroxypropyl acrylate, 2-perfluorohexylethyl acrylate, 3-perfluorohexyl-2-hydroxypropyl acrylate, 2-perfluorooctylethyl acrylate, 3-perfluorooctyl-2-hydroxypropyl acrylate, 2-perfluorodecylethyl acrylate, and 2-perfluoro-3-methylbutyl acrylate. ethyl acrylate, 3-perfluoro-3-methoxybutyl-2-hydroxypropyl acrylate, 2-perfluoro-5-methylhexylethyl acrylate, 3-perfluoro-5-methylhexyl-2-hydroxypropyl acrylate, 2-perfluoro-7-methyloctyl-2-hydroxypropyl acrylate, tetrafluoropropyl acrylate, octafluoropentyl acrylate, dodecafluoroheptyl acrylate, hexadecafluorononyl acrylate, hexafluorobutyl acrylate, 2,2,2-trifluoroethyl methacrylate, 2,2,3,3,3-Pentafluoropropyl methacrylate, 2-perfluorobutylethyl methacrylate, 3-perfluorobutyl-2-hydroxypropyl methacrylate, 2-perfluorooctylethyl methacrylate, 3-perfluorooctyl-2-hydroxypropyl methacrylate, 2-perfluorodecylethyl methacrylate, 2-perfluoro-3-methylbutylethyl methacrylate, 3-perfluoro-3-methylbutyl-2-hydroxypropyl methacrylate, 2-perfluoro-5-methylhexylethyl methacrylate, 3-perfluoro-5-methylhexyl Examples of perfluoro-2-hydroxypropyl methacrylate include 2-perfluoro-7-methyloctylethyl methacrylate, 3-perfluoro-6-methyloctyl methacrylate, tetrafluoropropyl methacrylate, octafluoropentyl methacrylate, octafluoropentyl methacrylate, dodecafluoroheptyl methacrylate, hexadecafluorononyl methacrylate, 1-trifluoromethyltrifluoroethyl methacrylate, hexafluorobutyl methacrylate, and triacryloyl-heptadecafluorononenyl-pentaerythritol.

[0185] Commercially available examples of the fluorine-based UV-curable functional group-containing compound include KY-1203 (manufactured by Shin-Etsu Silicones Co., Ltd.), OPTOOL DAC-HP (manufactured by Daikin Corporation), and UVAS-2003 (manufactured by Sooyang Chemtec Co., Ltd.).

[0186] The fluorine-based UV-curable functional group-containing compound may be included in the hard coating composition in an amount of more than 0.01% by weight and less than 10% by weight, based on 100% by weight of the total hard coating composition. When the fluorine-based UV-curable functional group-containing compound is included within this range, it is possible to impart excellent abrasion resistance and antifouling properties, which is preferable. If the content of the fluorine-based UV-curable functional group-containing compound is less than this range, it may be difficult to achieve sufficient abrasion resistance or antifouling properties, and if it is more than this range, hardness and / or scratch resistance may be reduced.

[0187] In one embodiment of the present invention, the photoinitiator is included to induce photocuring of the hard coating composition, and may include, for example, a photoradical initiator capable of forming radicals upon irradiation with light.

[0188] Examples of the photoinitiator include Type 1 initiators, which generate radicals by molecular decomposition due to differences in chemical structure or molecular bond energy, and Type 2 initiators, which induce hydrogen capture in the presence of tertiary amines.

[0189] For example, the Type 1 initiator may include acetophenones such as 4-phenoxydichloroacetophenone, 4-t-butyldichloroacetophenone, 4-t-butyltrichloroacetophenone, diethoxyacetophenone, 2-hydroxy-2-methyl-l-phenylpropan-1-one, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one, 1-(4-dodecylphenyl)-2-hydroxy-2-methylpropan-1-one, 4-(2-hydroxyethoxy)-phenyl(2-hydroxy-2-propyl)ketone, and 1-hydroxycyclohexylphenyl ketone; benzoins such as benzoin methyl ether, benzoin ethyl ether, and benzil dimethyl ketal; phosphine oxides; and titanocene compounds.

[0190] For example, Type 2 initiators include benzophenones such as benzophenone, benzoylbenzoic acid, benzoylbenzoic acid methyl ether, 4-phenylbenzophenone, hydroxybenzophenone, 4-benzol-4'-methyldiphenyl sulfide, and 3,3'-methyl-4-methoxybenzophenone; and thioxanthones such as thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, and isopropylthioxanthone.

[0191] The above-mentioned photoinitiators may be used alone or in combination of two or more. The Type 1 and Type 2 photoinitiators may be used alone or in combination.

[0192] The photoinitiator may be included in an amount of about 0.1 to 10 wt %, preferably about 1 to 5 wt %, based on 100 wt % of the total hard coating composition. If the photoinitiator content is less than 0.1 wt %, sufficient curing may not occur, and the mechanical properties and adhesion of the hard coating film or hard coating layer may not be ensured. Furthermore, if the photoinitiator content exceeds 10 wt %, poor adhesion, cracking, and curling may occur due to curing shrinkage.

[0193] The solvent may be any solvent known in the art that can dissolve or disperse the above-mentioned components, and is not particularly limited. The solvent also serves to provide time for the fluorine-based UV-curable functional group-containing compound to rise to the outermost surface of the coating layer due to the difference in surface tension during the process of applying the hard coating composition to a substrate and drying it.

[0194] Usable solvents include alcohols (methanol, ethyl alcohol, isopropanol, butanol, methyl cellosolve, ethyl cellosolve, etc.), ketones (methyl ethyl ketone, methyl butyl ketone, methyl isobutyl ketone, diethyl ketone, dipropyl ketone, cyclohexanone, etc.), acetates (ethyl acetate, propyl acetate, n-butyl acetate, t-butyl acetate, methyl cellosolve acetate, ethyl cellosolve acetate, propylene glycol monomethyl ether acetate, propylene glycol Preferred solvents that can be used include ethanol monoethyl ether acetate, propylene glycol monopropyl ether acetate, methoxybutyl acetate, methoxypentyl acetate, etc., hexanes (hexane, heptane, octane, etc.), benzenes (benzene, toluene, xylene, etc.), ethers (diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dipropyl ether, diethylene glycol dibutyl ether, propylene glycol monomethyl ether, etc.), etc. The solvents exemplified above can be used alone or in combination of two or more.

[0195] Preferably, a good solvent alone or a mixed solvent of a good solvent and a poor solvent is used as the solvent. The good solvent and the poor solvent may be appropriately selected depending on the material of the transparent film used as the substrate film.

[0196] The solvent may be included in an amount of 10 to 95 wt % based on 100 wt % of the total hard coating composition. If the solvent content is less than this range, the viscosity will be high, resulting in poor workability and insufficient swelling of the substrate. Conversely, if the solvent content exceeds this range, the drying process will take a long time, reducing economic efficiency, and the substrate film will swell severely, causing haze. Therefore, the solvent should be used appropriately within this range.

[0197] The hard coating composition may further comprise inorganic particles.

[0198] The inorganic particles may be inorganic nanoparticles, and are a component added to improve the elastic recovery rate of the hard coating layer.

[0199] Specifically, when the inorganic nanoparticles are contained in the hard coating composition, the mechanical properties can be further improved. More specifically, the inorganic nanoparticles are uniformly distributed in the coating film, which can improve mechanical properties such as pen indentation and pencil hardness.

[0200] The inorganic nanoparticles may have an average particle size of 1 to 100 nm, specifically 1 to 80 nm, and more specifically 5 to 50 nm. When the average particle size of the inorganic nanoparticles falls within this range, there is an advantage in that aggregation in the composition is prevented, thereby enabling the formation of a uniform coating film. Furthermore, the problem of deterioration in the optical and mechanical properties of the coating film can be prevented.

[0201] The inorganic nanoparticles may include, but are not limited to, one or more of the group consisting of Al2O3, SiO2, ZnO, ZrO2, BaTiO3, TiO2, Ta2O5, Ti3O5, ITO, IZO, ATO, ZnO-Al, Nb2O3, SnO, and MgO, and may include metal oxides commonly used in the art.

[0202] Specifically, the inorganic nanoparticles may be Al2O3, SiO2, and / or ZrO2. The inorganic nanoparticles may be directly produced or may be purchased from the market. In the case of commercially available products, they may be dispersed in an organic solvent at a concentration of 10 to 80 wt%.

[0203] The hard coating composition may further include a leveling agent to provide smoothness and coatability to the coating film when the composition is coated. The leveling agent may be selected from commercially available silicone-based leveling agents, fluorine-based leveling agents, and acrylic polymer-based leveling agents. For example, the leveling agent may be BYK-323, BYK-331, BYK-333, BYK-337, BYK-373, BYK-375, BYK-377, or BYK-378 manufactured by BYK-Chemie; TEGO Glide 410, TEGO Glide 411, TEGO Glide 415, TEGO Glide 420, TEGO Glide 432, TEGO Glide 435, TEGO Glide 440, TEGO Glide 450, TEGO Glide 455, TEGO Rad 2100, TEGO Rad 2200N, TEGO Rad 2250, TEGO Rad 2300, or TEGO Rad 2500 manufactured by 3M; or FC-4430 or FC-4432 manufactured by 3M. The leveling agent may be contained in the range of 0.1 to 1% by weight relative to 100% by weight of the entire hard coating composition.

[0204] In addition to the above-mentioned components, the hard coating composition may further contain components commonly used in the art, such as ultraviolet stabilizers, heat stabilizers, antioxidants, lubricants, and antifouling agents.

[0205] UV stabilizers are additives added to protect the surface of a cured coating film by blocking or absorbing UV light, which can cause decomposition, discoloration, and brittleness due to continued exposure to UV light. UV stabilizers are classified into absorbers, quenchers, and hindered amine light stabilizers (HALS) based on their mechanism of action. They are also classified into phenyl salicylate (absorber), benzophenone (absorber), benzotriazole (absorber), nickel derivatives (quencher), and radical scavengers based on their chemical structure. There are no particular restrictions on the UV stabilizer, as long as it does not significantly change the initial color of the coating film.

[0206] The heat stabilizer may be a polyphenol-based primary heat stabilizer, a phosphite-based secondary heat stabilizer, or a lactone-based secondary heat stabilizer, which are commercially available products and may be used alone or in combination.

[0207] The UV stabilizer and heat stabilizer may be used in an amount that does not affect the UV curability.

[0208] The hard coating layer can be formed by applying the hard coating composition onto the base resin layer, drying it, and then curing it with UV light.

[0209] The hard coating composition can be applied to the base resin layer (coating process) by appropriately using a known method such as a die coater, an air knife, a reverse roll, a spray, a blade, casting, gravure, microgravure, or spin coating.

[0210] After the hard coating composition is applied to the base resin layer, it is dried at a temperature of 30 to 150°C for 10 seconds to 1 hour, more specifically, for 30 seconds to 30 minutes to evaporate volatiles, and then cured by irradiating with UV light. The irradiation dose of the UV light is specifically about 0.01 to 10 J / cm. 2 More specifically, 0.1 to 2 J / cm 2 It may be.

[0211] The thickness of the hard coating layer formed may be specifically 1 to 10 μm, more specifically 3 to 10 μm. When the thickness of the hard coating layer falls within this range, excellent hardness, flex resistance, and curl properties can be obtained.

[0212] One embodiment of the present invention relates to an image display device including the above-described optical laminate. For example, the optical laminate of the present invention may be used as a window for an image display device, particularly a flexible display, a foldable display, a rollable display, or a stretchable display. In addition, the optical laminate of the present invention may be attached to a polarizing plate, a touch sensor, or the like.

[0213] The optical laminate according to one embodiment of the present invention may be used in reflective, transmissive, or semi-transmissive LCDs, or LCDs of various driving types such as TN, STN, OCB, HAN, VA, or IPS. The optical laminate according to one embodiment of the present invention may also be used in various image display devices such as plasma displays, field emission displays, organic EL displays, inorganic EL displays, and electronic paper.

[0214] One embodiment of the present invention relates to a variable transmittance optical laminate including the optical laminate described above.

[0215] The variable transmittance optical laminate has a laminated structure in which a polarizing plate and a liquid crystal layer are disposed inside, and transparent members are disposed on both sides of the polarizing plate and the liquid crystal layer to protect them. The variable transmittance optical laminate according to the present invention uses the above-mentioned optical laminate as the transparent member.

[0216] Furthermore, one embodiment of the present invention relates to a smart window including the variable transmittance optical stack.

[0217] The smart window may be applied to at least one of a front window, a rear window, a side window, a sunroof window, and an interior partition of an automobile, or may be applied to a window for a building. [Example]

[0218] The present invention will be described in more detail below with reference to examples, comparative examples, and experimental examples. However, it will be obvious to those skilled in the art that these examples, comparative examples, and experimental examples are merely for the purpose of illustrating the present invention, and that the scope of the present invention is not limited thereto.

[0219] Production Example 1: Production of primer layer-forming composition 22.67 wt% of water-based polyurethane (hereinafter referred to as PUD) (Akuarane 3410, manufactured by T&L, solids content 30 wt%), 77.08 wt% of ethyl alcohol, and 0.1 wt% of a silicone-based leveling agent (BYK-333, manufactured by BYK-Chemie) were diluted using a mixer, and 0.075 wt% of a primary stabilizer (STAB AO-80, manufactured by ADEKA Corporation) and 0.075 wt% of a secondary stabilizer (STAB 135A, manufactured by ADEKA Corporation) were further added and stirred to produce a composition for forming a primer layer.

[0220] Production Example 2-1: Production of composition for forming base resin layer Under a nitrogen gas atmosphere, 14.67 g (45.8 mmol) of 2,2'-bis(trifluoromethyl)benzidine (TFMB) and 233.3 g of N,N-dimethylacetamide (DMAc) with a water content of 200 ppm were added to a 1 L separable flask equipped with a stirring blade. TFMB was dissolved in the DMAc with stirring at room temperature. Next, 4.283 g (13.8 mmol) of 4,4'-oxydiphthalic dianhydride (OPDA) was added to the flask and stirred at room temperature for 16.5 hours. Next, 1.359 g (4.61 mmol) of 4,4'-oxybis(benzoyl chloride) (OBBC) and 5.609 g (27.6 mmol) of terephthaloyl chloride (TPC) were added to the flask and stirred at room temperature for 1 hour. Next, 4.937 g (48.35 mmol) of acetic anhydride and 1.501 g (16.12 mmol) of 4-picoline were added to the flask, and after stirring at room temperature for 30 minutes, the temperature was raised to 70° C. using an oil bath and stirring was continued for a further 3 hours to obtain a reaction liquid.

[0221] After the resulting reaction solution was cooled to room temperature, 360 g of methanol and 170 g of ion-exchanged water were added to obtain a polyamideimide precipitate. The precipitate was immersed in methanol for 12 hours, recovered by filtration, and washed with methanol. The precipitate was then dried under reduced pressure at 100°C to obtain a polyamideimide resin.

[0222] N,N-dimethylacetamide (DMAc) was added to the obtained polyamideimide resin so that the concentration became 15% by weight, thereby producing a composition for forming a base resin layer.

[0223] Production Example 2-2: Production of composition for forming base resin layer Under a nitrogen atmosphere, 45 g (140.5 mmol) of 2,2'-bis(trifluoromethyl)benzidine (TFMB) and 600.9 g of N,N-dimethylacetamide (DMAc) with a water content of 200 ppm were added to a 1 L separable flask equipped with a stirring blade. TFMB was dissolved in the DMAc with stirring at room temperature. Next, 4.14 g (14.1 mmol) of 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA) was added to the flask and stirred at room temperature for 2.5 hours. Then, 25.01 g (56.3 mmol) of 4,4'-(hexafluoroisopropylidene)diphthalic dianhydride (6FDA) was added and stirred at room temperature for 15 hours. Next, 4.15 g (14.1 mmol) of 4,4'-oxybis(benzoyl chloride) (OBBC) and 11.43 g (56.3 mmol) of terephthaloyl chloride (TPC) were added to the flask and stirred at room temperature for 1 hour. Next, 21.55 g (211.1 mmol) of acetic anhydride and 3.28 g (35.2 mmol) of 4-picoline were added to the flask and stirred at room temperature for 30 minutes. After that, the temperature was raised to 70 °C using an oil bath and stirred for an additional 3 hours to obtain a reaction solution.

[0224] After the resulting reaction solution was cooled to room temperature, 647 g of methanol and 180 g of ion-exchanged water were added to obtain a polyamideimide precipitate. The precipitate was immersed in methanol for 12 hours, recovered by filtration, and washed with methanol. The precipitate was then dried under reduced pressure at 100°C to obtain a polyamideimide resin.

[0225] N,N-dimethylacetamide (DMAc) was added to the obtained polyamideimide resin so that the concentration became 15% by weight, thereby producing a composition for forming a base resin layer.

[0226] Preparation Example 3: Preparation of hard coating composition 23 parts by weight of hexafunctional urethane acrylate (UA-306I, manufactured by Kyoeisha Chemical Co., Ltd.), 23 parts by weight of dendritic acrylate (Miramer SP1106, manufactured by Miwon Specialty Chemical Co., Ltd.), 50 parts by weight of methyl ethyl ketone, 3.5 parts by weight of 1-hydroxycyclohexyl phenyl ketone, and 0.5 parts by weight of a fluorine-based UV-curable functional group-containing compound (KY-1203, manufactured by Shin-Etsu Silicones Co., Ltd.) were mixed in a mixer and filtered using a PP filter to prepare a hard coating composition.

[0227] Manufacturing Example 4: Manufacturing of adhesive sheets A 1 L reactor was charged with a monomer mixture containing 40 wt % 2-ethylhexyl acrylate (2-EHA), 40 wt % isobornyl acrylate (IBOA), 10 wt % dihydrodicyclopentadienyl acrylate (DCPA), and 10 wt % 2-hydroxyethyl acrylate (2-HEA) adjusted to a solids content of 20 wt %, along with ethyl acetate (EA) as a solvent.

[0228] Nitrogen gas was purged for 1 hour to remove oxygen, and the temperature was maintained at 80° C. After the monomer mixture was uniformly mixed, 0.07 parts by weight of azobisisobutyronitrile (AIBN) was added as a reaction initiator and reacted for 8 hours to produce an acrylic random copolymer.

[0229] To 100 parts by weight of the acrylic random copolymer thus produced, 10 parts by weight of CL-467 (trimethylolpropane tris(2-methyl-1-aziridinepropionate), manufactured by MENADIONA) as a tackifier and 0.1 parts by weight of KBM-403 (3-glycidoxypropyltrimethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd.) as a silane coupling agent were added, and the mixture was stirred for 30 minutes to produce a pressure-sensitive adhesive composition.

[0230] The prepared pressure-sensitive adhesive composition was applied to a 75 μm release film coated with a silicone release agent so that the thickness after drying would be 25 μm, and after drying at 120° C. for 5 minutes, a 75 μm release film coated with a silicone release agent was laminated to prepare a pressure-sensitive adhesive sheet.

[0231] Examples 1 to 4 and Comparative Examples 1 to 3: Preparation of optical laminates An optical laminate was produced with a laminate structure as shown in FIG.

[0232] As the glass substrate, ultra-thin glass having the thickness shown in Table 2 below was prepared.

[0233] To perform dipping coating on the four sides of the ultra-thin glass, a water tank was filled with a certain amount of the primer layer-forming composition of Preparation Example 1. All four sides of the ultra-thin glass were dipped in the primer layer-forming composition of Preparation Example 1 by about 1 mm, and then immediately removed and dried in an oven at 120°C for 2 minutes to form a primer layer with a thickness shown in Table 2 below.

[0234] Next, a 25 μm heat-sensitive adhesive (CS2325NA4, manufactured by Nitta Corporation) was bonded to one surface of the ultra-thin glass, and this was again attached to a reinforcing glass that was larger than the glass substrate and had a thickness of 3T. Next, the primer layer-forming composition of Production Example 1 was applied to the other surface of the ultra-thin glass so that the thickness after drying was as shown in Table 2 below, and the composition was dried in an oven at 120° C. for 2 minutes to form a primer layer on the upper surface of the ultra-thin glass.

[0235] Next, the composition for forming the base resin layer of Manufacturing Example 2-1 was applied onto the primer layer using an applicator to cover the top and side surfaces of the primer layer, so that the thickness after drying would be the thickness shown in Table 2 below, and the composition was dried in an oven at 80°C for 1 hour and then in an oven at 210°C for 1 hour to form a base resin layer.

[0236] Next, the hard coating composition of Preparation Example 3 was applied to the upper surface of the base resin layer so that the thickness after drying was as shown in Table 2 below, and the applied hard coating composition was dried in an oven at 80°C for 2 minutes. Then, the applied hard coating composition was dried in a nitrogen atmosphere with a UV integrated light dose of 600 mJ / cm. 2 to form a functional coating layer.

[0237] The optical laminate was then placed on a -20°C plate for 5 minutes to reduce the adhesive strength of the heat-sensitive adhesive, and then peeled off from the reinforcing glass. The functional coating layer was then cut with a CO2 laser (LCP-C600, manufactured by Laser & Physics) at an output of 30% and a speed of 700 mm / s, offsetting 500 μm from the edge of the ultra-thin glass, to produce an optical laminate with a protected cross section.

[0238] [Table 2]

[0239] Example 5: Preparation of optical laminate An optical laminate was produced in the same manner as in Example 3, except that the composition for forming a base resin layer of Production Example 2-2 was used instead of the composition for forming a base resin layer of Production Example 2-1.

[0240] Example 6: Preparation of optical laminate An optical laminate was produced with a laminate structure as shown in FIG.

[0241] An ultra-thin glass substrate with a thickness of 90 μm was prepared.

[0242] To perform dipping coating on the four sides of the ultra-thin glass, a water tank was filled with a certain amount of the primer layer-forming composition of Preparation Example 1. All four sides of the ultra-thin glass were dipped in the primer layer-forming composition of Preparation Example 1 by about 1 mm, then immediately removed and dried in an oven at 120°C for 2 minutes to form a primer layer with a dry thickness of 0.5 μm.

[0243] Next, a 25 μm heat-sensitive adhesive (CS2325NA4, manufactured by Nitta Corporation) was bonded to one surface of the ultra-thin glass, and this was again attached to a reinforcing glass that was larger than the glass substrate and had a thickness of 3T. Next, the primer layer-forming composition of Production Example 1 was applied to the other surface of the ultra-thin glass so that the thickness after drying would be 0.5 μm, and this was dried in an oven at 120° C. for 2 minutes to form a primer layer on the upper surface of the ultra-thin glass.

[0244] Next, the composition for forming the base resin layer of Manufacturing Example 2 was applied onto the primer layer using an applicator to cover the top and side surfaces of the primer layer so that the thickness after drying would be 12 μm, and the composition was dried in an oven at 80°C for 1 hour and then in an oven at 210°C for 1 hour to form a base resin layer.

[0245] The optical laminate was then placed on a plate at -20°C for 5 minutes to reduce the adhesive strength of the heat-sensitive adhesive, and then peeled off from the reinforcing glass. The reinforcing glass was then attached to the base resin layer using the heat-sensitive adhesive.

[0246] Next, a primer layer was formed on the remaining surface of the ultra-thin glass in the same manner as above so that the thickness after drying would be 0.5 μm, and then a base resin layer was formed in sequence so that the thickness after drying would be 11.5 μm.

[0247] Next, the hard coating composition of Preparation Example 3 was applied to the substrate resin layer present on the upper surface of the ultra-thin glass so as to have a thickness of 5 μm after drying, and dried in an oven at 80° C. for 2 minutes. Then, the composition was dried in a nitrogen atmosphere with a UV integrated light dose of 600 mJ / cm 2 2 to form a functional coating layer.

[0248] Finally, the optical laminate was placed on a plate at -20°C for 5 minutes to reduce the adhesive strength of the heat-sensitive adhesive, and then peeled off from the reinforcing glass. Next, the functional coating layer was cut with a CO2 laser (LCP-C600, manufactured by Laser & Physics) at 30% power and a speed of 700 mm / s, offsetting 500 μm from the edge of the ultra-thin glass, to produce an optical laminate with a protected cross section.

[0249] Comparative Example 4: Preparation of optical laminate An ultra-thin glass substrate with a thickness of 90 μm was prepared.

[0250] The hard coating composition of Production Example 3 was applied to a 30 μm thick polyamideimide film (PAI, manufactured by Sumitomo Chemical Co., Ltd.) so that the thickness after drying would be 5 μm, and the coating was dried in an oven at 80° C. for 2 minutes. The coating was then dried in a nitrogen atmosphere with a UV integrated light dose of 600 mJ / cm 2 2 to form a functional coating layer.

[0251] Next, the release film of the pressure-sensitive adhesive sheet of Production Example 4 was peeled off, and the sheet was laminated using a laminator to the side of the polyamideimide film on which the functional coating layer was not formed. The functional coating film including the pressure-sensitive adhesive layer thus produced was cut with a super cutter to a size 1 mm larger than the size of the glass substrate, and the remaining release film was peeled off, and the film was laminated to one side of the glass substrate using a laminator to produce an optical laminate including a glass substrate.

[0252] Comparative Example 5: Preparation of optical laminate An ultra-thin glass substrate with a thickness of 90 μm was prepared.

[0253] The primer layer-forming composition of Production Example 1 was applied to one surface of the ultra-thin glass to a dried thickness of 0.5 μm, and dried in an oven at 120°C for 2 minutes to form a primer layer. Next, the base resin layer-forming composition of Production Example 2 was applied onto the primer layer using an applicator to a dried thickness of 20 μm, and dried in an oven at 80°C for 1 hour and then in an oven at 210°C for 1 hour to form a base resin layer. Next, the hard coating composition of Production Example 3 was applied onto the base resin layer to a dried thickness of 5 μm, and dried in an oven at 80°C for 2 minutes, and then dried in a nitrogen atmosphere with a UV integrated light dose of 600 mJ / cm. 2 A functional coating layer was formed by irradiating the glass substrate with light, and an optical laminate including the glass substrate was produced.

[0254] Experimental Example 1: The physical properties of the optical laminates produced in the examples and comparative examples were measured by the methods described below, and the results are shown in Tables 3 and 4. In addition, when d1 is the thickness of the glass substrate and d2 is the total thickness of the primer layer, substrate resin layer, and functional coating layer, the value of d2 / d1 was calculated and shown in Table 3. Furthermore, the total thickness of the optical laminate was also calculated and shown in Table 3.

[0255] (1) Elastic modulus of the base resin layer Each of the compositions for forming a base resin layer of Production Examples 2-1 and 2-2 was applied to a glass plate using an applicator so that the thickness after drying would be 20 μm. The coated film was then dried in an oven at 80° C. for 1 hour and then in an oven at 210° C. for 1 hour to form a base resin layer, which was then peeled off to obtain only the base resin layer. The base resin layer thus obtained was cut using a super cutter according to the JIS-K7139 bar-type standard to prepare test pieces for tensile evaluation. The elastic modulus (GPa) of the test pieces was measured using a universal testing machine in tensile evaluation mode at a tension speed of 4 mm / min.

[0256] (2) Pencil hardness After fixing the optical laminate with the hard coating layer facing up, the pencil hardness was measured under a load of 750 gf. The test was carried out five times with a 1 cm length using a pencil of the same hardness, and the hardness that was passed four or more times was recorded as the pencil hardness. In addition, when measuring the pencil hardness, if the glass substrate of the optical laminate did not break under a load of 750 gf, it was marked as "OK", and if it broke, it was marked as "NG".

[0257] (3) Flexibility A mandrel test was performed with a curvature radius of 3 mm so that the hard coating layer surface was bent inward, and the optical laminate was observed for fracture. The flex resistance was evaluated according to the following evaluation criteria. <Evaluation criteria> OK: No breakage of the optical laminate NG: Fracture of the optical laminate

[0258] (4) Curl characteristics An optical laminate measuring 10 cm x 10 cm was prepared and left at 25°C and 48% RH for 24 hours, after which the degree of lifting from the bottom of each corner was measured. The curl properties were evaluated according to the following evaluation criteria. <Evaluation criteria> OK: The average height of the squares is 3 mm or less NG: The average height of the squares rising is more than 3 mm

[0259] (5) Coating uniformity in the edge area The total thickness of the primer layer, substrate resin layer, and functional coating layer, excluding the glass substrate, was measured using a thickness gauge, and the coating uniformity (%) was calculated according to the following mathematical formula 2. The coating uniformity in the edge region was evaluated according to the following evaluation criteria. [Mathematical formula 2]

number

[0260] (6) Whether or not the sides are protected The side surface of the optical laminate was observed with an optical microscope to check for the presence or absence of a coating layer, and the result was evaluated according to the following evaluation criteria. <Evaluation criteria> ○: Coating layer on the side ×: No coating layer on the side

[0261] (7) Shatter prevention performance A 0.7 mm ballpoint pen (FX Zeta, manufactured by Monami Co., Ltd.) was allowed to freely drop from 10 cm above the optical laminate, impacting it into the edge region, which is an area within 3 mm from the edge of the glass substrate. The glass substrate was checked for damage and evaluated according to the following evaluation criteria. <Evaluation criteria> OK: There is no damage to the edge of the glass substrate, and even if it does break, the broken pieces (debris) are fixed to the substrate resin layer and functional coating layer and do not scatter. NG: The edge of the glass substrate is broken, and the resulting fragments (chips) are peeled off from the substrate resin layer and functional coating layer and scattered.

[0262] [Table 3]

[0263] [Table 4]

[0264] As can be seen from Table 3, the optical laminates of Examples 1 to 6, in which a primer layer, a substrate resin layer, and a functional coating layer were formed on an ultra-thin glass having a thickness of less than 100 μm according to the present invention such that the ratio of the total thickness (d2) of the primer layer, substrate resin layer, and functional coating layer to the thickness (d1) of the glass substrate, i.e., d2 / d1, was controlled to 0.1 to 0.4, were found to have excellent pencil hardness characteristics and to ensure bending resistance and curl characteristics.

[0265] In contrast, as seen in Table 3, the optical laminate of Comparative Example 1, in which the value of d2 / d1 was less than 0.1, showed such reduced hardness that the lower glass substrate cracked during pencil hardness measurement, and the optical laminate of Comparative Example 3, in which the value of d2 / d1 was more than 0.4, showed results in which pencil hardness, flex resistance, and curl properties could not be ensured simultaneously. Furthermore, the optical laminate of Comparative Example 2, in which the total thickness of the optical laminate was 120 μm or more, showed results in which flex resistance could not be ensured.

[0266] Furthermore, as can be seen from Table 4, the optical laminates of Examples 1 to 6, which have a structure in which a primer layer is formed on a glass substrate according to the present invention so as to cover the upper and side surfaces of the glass substrate, and a substrate resin layer is formed on the primer layer so as to cover the upper and side surfaces of the primer layer, have excellent coating uniformity in the edge region and protect the side surfaces of the glass substrate, thereby preventing the glass substrate from cracking due to external impact applied to the side surfaces, or preventing glass fragments from scattering even if the glass substrate is broken.

[0267] In contrast, as shown in Table 4, the optical laminate of Comparative Example 5, which has a structure in which a primer layer is formed only on the upper surface of the glass substrate and a substrate resin layer is formed only on the upper surface of the primer layer, showed poor coating uniformity in the edge region and the side surface of the glass substrate was not protected, resulting in the glass substrate cracking due to external impact applied to the side surface, and even causing glass fragments to fly when the glass substrate was cracked.

[0268] On the other hand, as can be seen from Tables 3 and 4, the optical laminate of Comparative Example 4, which has a structure in which a functional coating film is bonded to a glass substrate by an adhesive layer, does not protect the side surface of the glass substrate, and the overall thickness of the optical laminate is greater than 120 μm and has poor pencil hardness.

[0269] Although specific aspects of the present invention have been described in detail above, it will be apparent to those skilled in the art that such specific descriptions are merely preferred embodiments and are not intended to limit the scope of the present invention. Those skilled in the art will be able to make various applications and modifications within the scope of the present invention based on the above content.

[0270] Therefore, the true scope of the invention is to be defined by the following claims and their equivalents. [Explanation of symbols]

[0271] 110: Glass substrate 120: Primer layer 130: Base resin layer 140: Functional coating layer

Claims

1. Glass substrate, a primer layer formed on the glass substrate so as to cover the top and side surfaces of the glass substrate; a base resin layer formed on the primer layer so as to cover the upper and side surfaces of the primer layer; and An optical laminate comprising a functional coating layer formed on the base resin layer, The glass substrate is an ultra-thin glass having a thickness of less than 100 μm, The pencil hardness of the entire optical laminate is 2H or more, An optical laminate that satisfies the following mathematical formula 1. [Mathematical formula 1] 0.1≦d2 / d1≦0.4 In the above formula, d1 is the thickness of the glass substrate, and d2 is the total thickness of the primer layer, the substrate resin layer, and the functional coating layer.

2. The optical laminate according to claim 1 , wherein the primer layer is formed so as to cover the entire surface of the glass substrate.

3. The optical laminate according to claim 1 , wherein the base resin layer is formed so as to cover the entire surface of the primer layer.

4. The optical laminate according to claim 1 , having a total thickness of less than 120 μm.

5. The optical laminate according to claim 1 , wherein the primer layer comprises a water-based polyurethane resin and a stabilizer, and the stabilizer is formed from a primer layer-forming composition comprising a primary heat stabilizer and a secondary heat stabilizer.

6. 6. The optical laminate according to claim 5, wherein the primary heat stabilizer is at least one selected from a phenol-based heat stabilizer and an amine-based heat stabilizer, and the secondary heat stabilizer is at least one selected from a phosphorus-based heat stabilizer and a sulfur-based heat stabilizer.

7. The optical laminate according to claim 1 , wherein the base resin layer is formed from a composition for forming a base resin layer, the composition containing at least one resin selected from the group consisting of a polyimide resin and a polyamide-imide resin.

8. 2. The optical laminate according to claim 1, wherein the base resin layer has an elastic modulus of 3.3 to 5.2 GPa.

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