KR101481214B1 - The flexible display substrate - Google Patents

Abstract

The flexible display substrate of the present invention comprises a glass fiber layer and a resin layer formed on both sides of the glass bead layer, wherein the resin layer comprises a cured product of a photosensitive resin composition comprising a cadmium binder resin, a polyfunctional monomer and a photoinitiator.

Description

[0001] The flexible display substrate [0002]

The present invention relates to a flexible display substrate.

In recent years, a plasma display panel (PDP), a liquid crystal display (LCD), an organic EL (Organic Light Emitting Diode), or the like, which is a flat panel display in a conventional CRT (Cathode Ray Tube) In particular, in the future, researches are being actively carried out in the world to realize such a flat panel display as a flexible display.

In such a flat panel display, a substrate is basically used as a glass substrate. In a typical flat panel display, a glass substrate is used as a most suitable material for a TFT (thin film transistor) because a high temperature heat treatment is required to form the TFT.

However, since the glass substrate has basically too rigid properties, it has poor flexibility and is not suitable as a substrate for a flexible display.

In comparison with glass substrates, flexible display substrates are excellent in weight, formability, non-destructiveness, and design. In particular, they can be manufactured by a roll-to-roll production method, However, there has not been developed a flexible display substrate of a plastic material suitable for commercialization yet.

In order for such a plastic substrate to be a substrate of a flexible display, basically excellent light transmittance is required, and a combination of properties such as thermal stability, chemical resistance and surface flatness are required in a complex manner. In particular, Coefficient of Thermal Expansion (CTE).

Examples of the prior art related to the flexible display substrate include a glass fiber layer (hereinafter referred to as " glass fiber layer ") such as International Patent Publication No. 2011-0124522 (published on October 13, 2011), US Published Patent 2011-0244182 (published October 10, 2011), European Patent No. 1,524,301 And a resin layer formed on both surfaces of the glass fiber layer, wherein the resin layer is a resin composition comprising a unit structure from an acrylic monomer and a unit structure compound from a fluorene monomer, and the resin layer is used as a film for a flexible substrate have.

DISCLOSURE OF THE INVENTION The present invention is to provide a flexible display substrate having excellent optical properties and excellent thermal stability.

The flexible display substrate of the present invention comprises a glass fiber layer and a resin layer formed on both sides of the glass fiber layer, wherein the resin layer comprises a cationic copolymer resin, a polyfunctional monomer and a photoinitiator represented by the following formula And a cured product.

≪ Formula 1 >

Wherein R 1 and R 3 are each a hydrogen atom or a methyl group, Y is a residue of a first acid anhydride, Z is a residue of a second acid anhydride, and the molar ratio of m: n is 100: 0 to 0: 100.

According to a preferred embodiment of the present invention, the photosensitive resin composition is a photosensitive resin composition comprising 0.1 to 99 parts by weight of a polyfunctional monomer and 0.01 to 20 parts by weight of a photoinitiator based on 100 parts by weight of the cadmium-based copolymer resin.

In another embodiment of the present invention, the thickness of the glass fiber layer is 20 to 300 mu m.

In another embodiment of the present invention, it is preferable that the glass fiber layer has a glass fiber layer in a woven form in which glass fibers having a diameter of 4 to 20 μm are aligned in one direction and crosswise crosswise the warp yarns and weft yarns in the transverse and longitudinal directions Do.

Another embodiment of the present invention is a display device including a plastic substrate for a flexible display as a lower substrate.

The present invention provides a flexible display substrate having excellent optical properties while having excellent thermal stability.

The flexible display substrate of the present invention is a plastic substrate in which a glass fiber layer made of glass fiber is impregnated with a photosensitive resin composition to form a photosensitive resin composition layer on both sides of a glass fiber layer in order to maintain excellent optical properties as well as excellent thermal stability, And then adjusting the thickness thereof appropriately, followed by UV curing to form a resin layer.

In this case, the glass fiber layer may be aligned in one direction with a glass fiber having a diameter of 4 to 20 um and may be formed to a thickness of 20 to 300 탆. Such a glass fiber layer has excellent thermal properties, is not water absorbent and has low hygroscopicity. Because of its chemical durability, it does not corrode, has a strong tensile strength, has a small elongation, and has great electrical insulation.

According to one embodiment of the present invention, the resin layer comprises (A) a binder resin; (B) a polyfunctional monomer; And (C) a photoinitiator.

The present invention will be described in more detail as follows.

(A) Binder resin

BACKGROUND ART [0002] Binder resins are widely used for photosensitive resin compositions in recent years and include a polymer compound that forms a photoresist phase by reaction with light upon exposure to light and a photopolymerizable monomer component that reacts with light upon exposure to form a photoresist image . Typical examples of the binder resin include a carcass binder resin, an acrylic binder resin, a novolac binder resin, and the like.

Cadmium binder resins have a high refractive index and are easy to match refractive index with a glass fiber layer. Although they have excellent heat resistance and electrical properties, they have a disadvantage in that their molecular weight control is limited.

Acrylic binders can control the molecular weight and acid value according to the polymerization method, so that it is easy to control the pattern flowability, and it is possible to synthesize a binder suitable for the application by introducing various monomers.

The novolak type binder is a primary resin produced by an acidic catalyst during the production process of a phenol resin, and is a high-planar high-hardness resin having a high hardness. When an alkaline substance is added, the novolak-based binder has an excellent electrical insulating property.

The resin layer of the flexible display substrate of the present invention includes a binder resin, and when the binder resin is included, the thermal stability of the substrate is improved. For example, at least one of a cadmium-based binder resin and an alkali-soluble acrylic-based binder resin, particularly a cadmium binder resin in view of improving flexibility.

In the present invention, as the binder constituting the photosensitive resin composition, a copolymer formed by copolymerization with a monomer may be used. In addition to the copolymer, a polymer compound formed by bonding an ethylenically unsaturated compound containing an epoxy group to the copolymer structure may be used together.

Examples of the binder resin according to the present invention include a resin compound having a polyfunctional group structure having an acrylate group in the main chain, which is referred to as a cadmium-based binder resin represented by the following formula (1).

≪ Formula 1 >

(Wherein R1 and R3 are hydrogen atoms or methyl groups, Y is a residue of a first acid anhydride, Z is a residue of a second acid anhydride, and m: n is 100: 0 to 0: 100.

In the compound represented by Formula 1, Y is at least one selected from maleic anhydride, succinic anhydride, cis-1,2,3,6-tetrahydrophthalic anhydride, Anhydride, 3,4,5,6-tetrahydrophthalic anhydride, phthalic anhydride, itaconic anhydride, 1,2,4-benzene, 1,2,4-benzeneetricarboxylic anhydride, methyl-tetrahydrophthalic anhydride, citraconic anhydride, 2,3-dimethylmaleic anhydride, 1-cyclopentene-1,2-dicarboxylic anhydride, cis (5-norbornene-endo-2,3-dicarboxylic anhydride, cis- -endo-2,3-dicarboxylic anhydride and 1,8-naphthalic anhydride, Will.

Further, in the compound represented by the above formula (1), Z represents 1,2,4,5-benzenetetracarboxylic dianhydride, 4,4'-biphthalic dianhydride (4,4 '-Biphthalic Dianhydride, 3,3', 4,4'-benzophenonetetracarboxylic dianhydride, pyromelitic dianhydride, 1,4 , 5,8-naphthalenetetracarboxylic dianhydride, 1,2,4,5-tetracarboxylic anhydride, methyl norbornene Methylnorbonene-2,3-dicarboxylic anhydride, 4,4 '- [2,2,2-trifluoro-1- (trifluoromethyl) ethylidene] diphthalic anhydride 4,4'- [2,2,2-Trifluoroethyl] Ethylidene] Diphthalic Anhydride, 4,4'-Oxydiphthalic Anhydride and Ethylene Glycol Bis (Anhydro Trimellitate) (Ethylene Glycol Bis (Anhydro Trimelitate)) ≪ / RTI >

The compound represented by the general formula (1) has a ratio of m: n, which is the molar ratio of the first acid anhydride and the second acid anhydride, of 100: 0 to 0: 100, preferably 100: 0 to 50:50, 100: 0 to 70:30, and even more preferably 0: 100 to 50: 50, is excellent in solubility with a polyfunctional monomer and an initiator, is easy to impregnate with a glass fiber layer, It is preferable in improving the characteristics. The refractive index of the resin layer is greatly improved to minimize the refractive index with respect to the glass fiber layer and thereby the reflectance at the interface between the glass fiber layer and the resin layer is reduced to improve the overall light transmittance of the substrate. In addition, it has a stable aromatic molecular structure, has a high glass transition temperature, and greatly improves thermal stability. In addition, it has excellent abrasion resistance, which reduces the frequency of scratches and has excellent chemical resistance, which is a great help in not causing physical property changes in the subsequent processes and device fabrication.

It is preferable that the binder resin is contained in an amount of 5 to 80% by weight of the total resin composition in order to improve heat resistance after film-forming.

The photosensitive resin composition according to the present invention may include a compound represented by the formula (1) as an example of the binder resin. The compound represented by the formula (1) can be obtained, for example, by the following process: (Meth) acrylic acid of formula (3) to synthesize a compound represented by the formula (4), and treating the resulting mixture with a first acid anhydride or a second acid anhydride at both terminals to give a multifunctional The epoxy acrylate represented by the general formula (5) is reacted to synthesize the compound of the general formula (1).

(2)

(3)

(Wherein R is a hydrogen atom or a methyl group)

≪ Formula 4 >

(Wherein R1 is a hydrogen atom or a methyl group)

≪ Formula 5 >

(Wherein R is a hydrogen atom or a methyl group)

(B) a polyfunctional monomer

Examples of the polyfunctional monomer serving to form a network by light include propylene glycol methacrylate, dipentaerythritol hexaacrylate, dipentaerythritol acrylate, neopentyl glycol diacrylate, 1,6 Hexanediol diacrylate, 1,6-hexanediol acrylate, tetraethylene glycol methacrylate, bisphenoxy ethyl alcohol diacrylate, trishydroxyethylisocyanurate trimethacrylate, trimethylpropane trimethacrylate Or a mixture of two or more selected from the group consisting of pentaerythritol tetramethacrylate, pentaerythritol tetramethacrylate, and dipentaerythritol hexamethacrylate.

Examples of the acrylic or methacrylic compound having two or more functional groups include bisphenol-A-diacrylate, bisphenol-S diacrylate, dicyclopentadienyl diacrylate ( dicyclopentadienyl diacrylate, pentaerythritol triacrylate, tris (2-hydroxyethyl) isocyanurate triacrylate, pentaerythritol tetraacrylate (pentaerythritol tetraacrylate) ), Bisphenol-A dimethacrylate, bisphenol-S dimethacrylate, dicyclopentadienyl dimethacrylate, pentaerythritol trimethacrylate, Pentaerythritol trimethacrylate, tris (2-hydroxyethyl) isocyanurate trimethacrylate (tris (2-hydroxyethyl ) isocyanurate trimethacrylate, and pentaerythritol tetramethacrylate may be used.

It goes without saying that an acrylate compound having a fluorene skeleton structure such as fluorene acrylate having a divalent functional group may also be used. Specific examples thereof include compounds having a fluorene skeleton structure represented by the following formula (6).

(6)

(Wherein R ₁ to R ₆ are the same or different and each is a hydrogen atom or a hydrocarbon group of 1 to 10 carbon atoms which is substituted or unsubstituted with a linking group containing oxygen, nitrogen, sulfur or silicon, or a polar group, a single bond or a divalent linking group A silane group and a halogen atom, and n is an integer of 1 to 20.)

 The hydrocarbon group having 1 to 10 carbon atoms may be any one selected from the group consisting of a methyl group, an ethyl group, a propyl group, and a combination thereof; A cyclopentyl group, a cyclohexyl group, and a combination thereof; An alkenyl group selected from the group consisting of a vinyl group, an aryl group, a propenyl group, and combinations thereof; , And the like.

The substituted or unsubstituted hydrocarbon group may be bonded to the ring structure directly or via a linking group as shown in Formula (1).

The linking group may be a bivalent hydrocarbon group having 1 to 10 carbon atoms, a linking group containing oxygen, nitrogen, sulfur or silicon such as a carbonyl group, an oxycarbonyl group, a sphone group, an ether bond, a thioether bond, A siloxane bond, and the like, or a linking group including a plurality of these groups.

The polar group includes a hydroxyl group, an alkoxy group having 1 to 10 carbon atoms, a carbonyloxy group, an alcoholic carbonyl group, a cyano group, an amide group, an imide group, an amino group, an acyl group, a sulfonyl group and a carboxyl group. More specifically, examples of the alkoxy group include a methoxy group and an ethoxy group. Examples of the carbonyloxy group include an alkylcarbonyloxy group such as an acetoxy group and a propionyloxy group, an ethoxycarbonyl group and the like. Is a primary amino group.

The divalent linking group in the aromatic group having a single bond or a divalent linking group is preferably an alkylene group having 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms, such as a methylene group, an ethylene group, a trimethylene group, an arylene group, An alkylene group, an oxyarylene group, an oxycarbonyl group, an iminocarbonyl group, a carbonyl group, an acetylene group, a ureylene group, a hetero atom such as sulfur or oxygen, and an amino group. It is also possible to combine two or more of these connecting units.

The aromatic group should include an aromatic group through such a linkage, which includes a monohydroxy leaving group of an aromatic compound.

Specific examples of the monovalent hydrogen deficiency include benzene, pentane, naphthalene, azulene, heptarene, biphenylene, indacene, acenaphthalene, phenanthrene, anthracene, fluoransenes, , Naphthacene, prazene, picene, perylene, phenaphene, pentacene, tetraphenylene, hexaphene, penascene, rubicene, coronene, trinaphthylene, heptapene, And one or more of the group consisting of thiophene, thianthrene, furan, pyran, isobenzofuran, chromene, xanthene, phenoxathiine, pyrrole, imidazole, pyrazole, The present invention relates to a method for producing a compound represented by the general formula (1) or a salt thereof, wherein the compound is selected from the group consisting of isothiazole, isooxazole, pyridine, pyridine, pyrimidine, pyridine, indolidine, isoindole, indole, indazole, purine, quinolidine, isoquinone, quinoline, Xylylene, cyinoline, pteridine, carbazole, betacarbonyl, phenanthyridine, acry It is preferable to have any one of heterocyclic compounds and substituents thereof selected from the group consisting of pyridine, pyrimidine, phenanthroline, phenadine, phenarazine, phenothiazine, prazine, phenoxy and combinations thereof .

The silane group may be any one selected from the group consisting of a trimethoxysilyl group, a triethoxysilyl group, and a combination thereof, or any one selected from the group consisting of a trimethylsilic group, a triethylsilyl group, It is preferably a triorganosiloxy group.

Examples of the halogen atom include fluorine, chlorine, bromine and the like.

As a specific example, the fluorene-based monomer forming the unit structure from the monomer of Formula 2 is not particularly limited and may be any fluorene skeleton-containing acrylate having two or more functional groups. Examples of the fluorene skeleton structure include 9,9-bis (4-hydroxyphenyl) fluorene, 9,9-bis (4-hydroxy-3-methylphenyl) fluorene, 9,9- 3-fluorophenyl) fluorene, 9,9-bis (4-hydroxy-3-bromophenyl) fluorene, 9,9-bis (4-hydroxy-3-methoxyphenyl) fluorene, 9,9-bis 3,5-dichlorophenyl) fluorene, and 9,9-bis (4-hydroxy-3,5-dibromophenyl) fluorene.

The content thereof is preferably 0.1 to 99 parts by weight based on 100 parts by weight of the compound represented by the formula (1), because the bonding force is enhanced by cross-linking due to UV-induced radical reaction of the photoinitiator, so that the film is preferable for film having transparency and flexibility.

(C) Photo initiator

The photoinitiator may be Irgacure 907, Irgacure 369, Irgacure OXOl, Irgacure 242, thioxanthone, 2,4-diethylthioxanthone, thioxanthone-4-sulfonic acid, benzophenone, 4,4'- Benzophenone, acetophenone, p-dimethylaminoacetophenone,?,? '- dimethoxyacetoxybenzophenone, 2,2'-dimethoxy-2-phenylacetophenone, p- 2-diethylamino-1- (4-morpholinophenyl) -butan-1-one, 2-hydroxy- (2-hydroxy-2-propyl) ketone, 1-hydroxycyclohexyl phenyl ketone, and other ketones ; Quinones such as anthraquinone and 1,4-naphthoquinone; Tri (trichloromethyl) -s-triazine, 1,3-bis (trichloromethyl) -5- (2- chlorophenyl) Halogen compounds such as phenylphenyl) -s-triazine, phenacyl chloride, tribromomethylphenylsulfone, and tris (trichloromethyl) -s-triazine; Peroxide such as di-t-butyl peroxide; Acylphosphine oxides such as 2,4,6-trimethylbenzoyldiphenylphosphine oxide and the like can be used. In the present invention, the photoinitiators may be used alone or in combination.

The photoinitiator is preferably included in an amount of 0.01 to 20 parts by weight based on 100 parts by weight of the compound represented by the formula (1).

If the content of the photoinitiator is less than 0.01 part by weight, the sensitivity is insufficient and the conversion of the acrylic polymerization is 80% or less, tackiness of the sticky monomer may remain, and it is difficult to have the basic optical properties of the film to be formed. If the content of the photoinitiator is more than 20 parts by weight, the light transmittance, haze, yellow index, and the like of the formed film tend to decrease.

In order to control the viscosity of the photosensitive resin composition, a diluent may be used. The content of the diluent is preferably 10 to 300 parts by weight based on 100 parts by weight of the compound represented by the formula (1).

As the diluent, the following materials may be used for preparing the composition or maintaining the viscosity. For example, alcohols such as methanol and ethanol, ethers such as tetrahydrofuran, diethylene glycol dimethyl ether and diethylene glycol diethyl ether, propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, propylene glycol propyl ether acetate, propylene glycol And propyleneglycol alkyl ether acetates such as butyl ether acetate. Among these diluents, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, propylene glycol methyl ether acetate, methyl ethyl ketone, cyclohexanone, 4-hydroxycyclohexanone and the like are preferable from the viewpoints of solubility, reactivity with each component, Hydroxy-2-methylpropionic acid, ethyl ester of 2-hydroxy-2-methylpropionic acid, ethyl ester of 2-hydroxypropionic acid, Methyl ester, ethyl ester, butyl ester of lactic acid, ethyl lactate, propyl lactate, methyl ester of butyl methoxyacetic acid, ethyl ester, propyl ester, butyl ester methyl ester, ethyl ester, propyl ester, butyl ester moiety of propoxyacetic acid Methyl esters, ethyl esters, Butyl ester 2-methoxypropionic acid methyl ester, ethyl ester, propyl ester, butyl ester methyl ester, 2-ethoxypropionic acid methyl ester, ethyl ester, propyl ester, butyl ester methyl ester of 2-butoxypropionic acid, ethyl ester , Propyl esters, butyl esters Methyl esters, ethyl esters, propyl esters, butyl esters of 3-methoxypropane Methyl esters, ethyl esters, propyl esters, butyl esters of 3-ethoxypropionic acid Methyl esters of 3-butoxypropionic acid, ethyl The use of esters such as esters, propyl esters and butyl esters is preferred.

The diluent may also be used in combination with a high boiling point diluent. As the high boiling point diluent that can be used, there can be mentioned, for example, N-methylformamide, N, N-dimethylformamide, N-methylacetamide, N, N-dimethylacetamide, N-methylpyrrolidone, dimethylsulfoxide, .

The diluent is contained in an amount of 10 to 300 parts by weight based on 100 parts by weight of the compound represented by the general formula (1). When the content of the diluent is within the above range, a smooth film can be formed.

In addition, surfactants, curing accelerators, antioxidants and the like may be further added for the purpose of expressing special functions.

Examples of the surfactant include fluorine and silicon surfactants such as FC-129, FC-170C and FC-430 of 3M, F- 172, F-173, F-183, F-470, F-475 and KP322, KP323, KP340 and KP341 of Shin-Etsu Silicones. Such a surfactant may be contained in an amount of 5 parts by weight or less, preferably 2 parts by weight or less, based on 100 parts by weight of the composition. When the content of the surfactant is more than 5 parts by weight, foaming occurs at the time of application, and such a problem is undesirable because it affects glass fiber impregnation and film-forming.

The resin composition of the present invention may contain a small amount of an antioxidant, an ultraviolet absorber, a dyeing pigment, and the like insofar as the properties such as transparency, solvent resistance and heat resistance are not impaired, if necessary.

Hereinafter, the production example of the present invention will be described.

Production Example 1 Production of a cationic binder resin represented by the formula (1)

In a 1 L four-necked flask, 232 g of bisphenol fluorene-type epoxy compound and 72 g of acrylic acid were mixed with propylene glycol methyl ether acetate (PGMEA) as a solvent, 4.56 g of triethylamine and 100 mg of hydroquinone were added and dissolved by heating at 100 占 폚. The solution was slowly heated in a cloudy state and completely dissolved at 100 ° C. When completely dissolved, the temperature was maintained at 90 ° C, and nitrogen injection was performed at a rate of 25 ml / min, which required 12 hours until the acid value reached the target. The acid value was measured, and heating and stirring were continued until it was less than 3.0 mg KOH / g. The mixture was cooled to room temperature to obtain a colorless transparent bisphenol fluorene-type epoxy acrylate.

32.57 g of 1,2,3,6-tetrahydrophthalic anhydride was added to 300 g of bisphenol fluorene-type epoxy acrylate thus obtained, and the mixture was gradually heated to react at 120 DEG C for 20 hours to obtain a cadmium compound represented by the formula (1).

≪ Preparation Example 2 > : Example of synthesis of acrylic binder resin

The components shown in the following Table 1 were placed in a 1000 ml four-necked flask, and stirred for 30 minutes while blowing nitrogen therein. Next, the temperature was gradually raised, reacted at 65 ° C for 4 hours, heated to 80 ° C and reacted for 2 hours to synthesize an acrylic binder resin. In Table 1, the unit is g.

Raw material composition Usage (g) MAA 21.81 MMA 109.09 KBM503 87.27 Initiator 21.81 PGMEA 560

(Note) MAA: methacrylic acid, MMA: methyl methacrylate

KBM503: 3- (methacryloxypropyl) trimethoxysilane, Shin-Etsu Chemical product

Initiator: Azobisisobutyronitrile

PGMEA: Propylene glycol monomethyl ether acetate

≪ Examples 1 to 4 and Comparative Example 1 >

The components and the contents (weight%) as shown in Table 2 below were mixed and stirred for 3 hours to prepare a photosensitive resin composition. Then, 4 to 20 um of glass fibers were aligned in one direction to a thickness of 40 to 150 탆 And the thickness of the resin layer on one surface of the glass fiber layer was adjusted to be 40 to 130 탆 by using a doctor blade by placing the glass fiber layer between the glass substrate and the release film Thereafter, UV curing was carried out to obtain a substrate.

Formula 1
compound
(Production Example 1) Acrylic compound
(Production Example 2) Fluorene acrylate having a divalent functional group Multifunctional
Monomer diluent Photoinitiator Comparative Example 1 - - 53 25 20 2 Example 1 53 - - 25 20 2 Example 2 35 - 18 25 20 2 Reference Example 3 - 53 - 25 20 2 Reference Example 4 35 - 18 25 20 2

≪ Example 1 >

53 parts by weight of the compound of Formula 1 obtained in Preparation Example 1, 25 parts by weight of neopentyl glycol diacrylate, 2 parts by weight of 1-hydroxycyclohexyl phenyl ketone (Irgacure 184, manufactured by Basf), 20 parts by weight of propylene glycol ethyl ether acetate Were mixed to prepare a resin layer composition before curing. The resin layer composition before curing was impregnated with glass fibers having a thickness of 100 mu m and sonicated for 30 minutes. Two release films were placed in two glass substrates, a glass fiber layer was spread out therefrom, the thickness of the resin layer was adjusted to 100 탆 by using a doctor blade, and the both sides were irradiated with UV light of about 10 J / cm 2 And the glass substrate and the release film were removed to obtain a substrate.

≪ Example 2 >

, 35 parts by weight of the compound of Formula 1 obtained in Preparation Example 1, 18 parts by weight of fluorene acrylate having a bivalent functional group (HR-6060, product of MIWON SPECIALTY CHEMICAL), 25 parts by weight of neopentyl glycol diacrylate, 2 parts by weight of cyclohexyl phenyl ketone (Irgacure 184, manufactured by Basf) and 20 parts by weight of propylene glycol ethyl ether acetate were further mixed to prepare a resin layer composition before curing. The resin layer composition before curing was impregnated with glass fibers having a thickness of 100 mu m and sonicated for 30 minutes. Two release films were placed in two glass substrates, a glass fiber layer was spread out therefrom, the thickness of the resin layer was adjusted to 100 탆 by using a doctor blade, and the both sides were irradiated with UV light of about 10 J / cm 2 And the glass substrate and the release film were removed to obtain a substrate.

≪ Reference Example 1 &

53 parts by weight of the acrylic compound obtained in Preparation Example 2, 25 parts by weight of neopentyl glycol diacrylate, 2 parts by weight of 1-hydroxycyclohexyl phenyl ketone (Irgacure 184, manufactured by Basf) and 20 parts by weight of propylene glycol ethyl ether acetate Followed by further mixing to prepare a resin layer composition before curing. The resin layer composition before curing was impregnated with glass fibers having a thickness of 100 mu m and sonicated for 30 minutes. Two release films were placed in two glass substrates, a glass fiber layer was spread out therefrom, the thickness of the resin layer was adjusted to 100 탆 by using a doctor blade, and the both sides were irradiated with UV light of about 10 J / cm 2 And the glass substrate and the release film were removed to obtain a substrate.

≪ Reference Example 2 &

, 35 parts by weight of the acrylic compound obtained from Preparation Example 2, 18 parts by weight of fluorene acrylate having a bivalent functional group (HR-6060, product of MIWON SPECIALTY CHEMICAL Co.), 25 parts by weight of neopentyl glycol diacrylate, 2 parts by weight of hexyl phenyl ketone (Irgacure 184, manufactured by Basf) and 20 parts by weight of propylene glycol ethyl ether acetate were further mixed to prepare a resin layer composition before curing. The resin layer composition before curing was impregnated with glass fibers having a thickness of 100 mu m and sonicated for 30 minutes. Two release films were placed in two glass substrates, a glass fiber layer was spread out therefrom, the thickness of the resin layer was adjusted to 100 탆 by using a doctor blade, and the both sides were irradiated with UV light of about 10 J / cm 2 And the glass substrate and the release film were removed to obtain a substrate.

≪ Comparative Example 1 &

A substrate was prepared in the same manner as in Example 1, except that 53 parts by weight of fluorene acrylate having a bivalent functional group (HR-6060, manufactured by MI WON SPECIALTY CHEMICAL Co.) instead of the compound represented by the formula (1) was used.

The results of evaluating the performance of Examples 1 to 2, Reference Examples 1 to 2 and Comparative Example 1 thus obtained are shown in Table 3 below, and the measurement method of each evaluation item is as follows.

<Haze measurement method>

Using a haze meter (model NDH2000, manufactured by Nippon Denshoku), the haze of the film is measured with a D65 light source in Method3.

<Measurement method of Y.I>

The yellow index of the film was measured using a UV-Vis spectrometer (CARY-100 model manufactured by Varian) using ASTM E313 measurement method.

<Analysis method of thermogravimetric analyzer>

Under N2 condition, the temperature was raised from room temperature to 300 ° C at a rate of 10 ° C / min, and a weight loss (%) occurring at 280 ° C for 1 hour was observed.

<How to check Flexibility>

If the film is broken or broken by bending the film, Flexibility is not indicated and it is expressed as x. If the state of the film is maintained even after ten rounds of bending work, Flexibility is indicated by o.

Haze (%) YI Thermogravimetric analysis (%) Flexibility Comparative Example 1 11 6.5 11 o Example 1 8 6.3 2 o Example 2 10 6.3 5 o Reference Example 1 22 6.4 4 x Reference Example 2 18 6.3 8 x

In the case of the cured product of the multifunctional monomers as in Comparative Example 1, the weight loss was 10% or more as a result of thermogravimetric analysis, but it was found that the contents of Examples 1 and 2 and Reference Examples 1 and 2 were reduced to 10% or less. From these results, it can be seen that when the thermogravimetric analysis is performed on the copolymer compound rather than the multifunctional monomer, the wt% loss is small.

On the other hand, when Examples 1 and 2 and Reference Examples 1 and 2 are compared, it can be seen that the cationic binder resin compound of Chemical Formula 1 improves the flexibility properties of the acrylic binder resin compound.

Claims (6)

A glass fiber layer and a resin layer formed on both sides of the glass fiber layer,
Wherein the resin layer comprises a cured product of a photosensitive composition comprising a cadmium-based copolymer resin represented by the following formula (1), a polyfunctional monomer and a photoinitiator.
&Lt; Formula 1 >

Wherein R 1 and R 3 are each a hydrogen atom or a methyl group, Y is a residue of a first acid anhydride, Z is a residue of a second acid anhydride, and the molar ratio of m: n is 100: 0 to 0: 100. The flexible display substrate according to claim 1, wherein the glass fiber layer has a glass fiber having a diameter of 4 to 20 um aligned in one direction and a thickness of 20 to 300 탆. The flexible display substrate of claim 1, wherein the photosensitive composition in the resin layer comprises from 0.1 to 99 parts by weight of a multifunctional monomer and from 0.01 to 20 parts by weight of a photoinitiator relative to 100 parts by weight of a cadmium-based copolymer resin. 4. The thermoplastic resin composition according to claim 3, wherein the polyfunctional monomer in the resin layer is selected from the group consisting of propylene glycol methacrylate, dipentaerythritol hexaacrylate, dipentaerythritol acrylate, neopentyl glycol diacrylate, 1,6- Diacrylate, 1,6-hexanediol acrylate, tetraethylene glycol methacrylate, bisphenoxy ethyl alcohol diacrylate, trishydroxyethylisocyanurate trimethacrylate, trimethylpropane trimethacrylate, penta Bisphenol-A-diacrylate, bisphenol-S diacrylate, dipentaerythritol tetramethacrylate, dipentaerythritol tetramethacrylate, pentaerythritol tetramethacrylate, S diacrylate, dicyclopentadienyl diacrylate, pentaerythritol triacrylate, but are not limited to, tris (2-hydroxyethyl) isocyanurate triacrylate, tris (2-hydroxyethyl) isocyanurate triacrylate, pentaerythritol tetraacrylate, bisphenol-A dimethacrylate, A dimethacrylate, bisphenol-S dimethacrylate, dicyclopentadienyl dimethacrylate, pentaerythritol trimethacrylate, tris (2-heptene) dimethacrylate, Wherein the flexible display substrate is at least one selected from the group consisting of tris (2-hydroxyethyl) isocyanurate trimethacrylate, pentaerythritol tetramethacrylate, and the like. The flexible display substrate according to claim 3, wherein the multifunctional monomer in the resin layer is selected from compounds represented by the following formula (6).
(6)

Herein, R ₁ to R ₆ are the same or different and each represents a hydrogen atom or a hydrocarbon group of 1 to 10 carbon atoms which is unsubstituted or substituted with a linking group containing oxygen, nitrogen, sulfur or silicon, or a polar group, a single bond or a divalent linking group The branch is selected from an aromatic group, a silane group, and a halogen atom; n is an integer of 1 to 20; The compound of claim 1, wherein Y is selected from the group consisting of maleic anhydride, succinic anhydride, cis-1,2,3,6-tetrahydrophthalic anhydride (cis-1,2 3,6-tetrahydrophthalic anhydride, 3,4,5,6-tetrahydrophthalic anhydride, phthalic anhydride, itaconic anhydride, 1, 1,2,4-benzenetricarboxylic anhydride, methyl-tetrahydrophthalic anhydride, citraconic anhydride, 2,3-dimethyl maleic anhydride, 2,3-dimethylmaleic anhydride, 1-cyclopentene-1,2-dicarboxylic anhydride, cis (5-norbornene-endo-2,3-dicarboxylic anhydride a first acid selected from cis-5-Norbonene-2,3-dicarboxylic anhydride and 1,8-naphthalic anhydride. A residue of an anhydride;
Z is selected from the group consisting of 1,2,4,5-benzene tetracarboxylic dianhydride, 4,4'-biphthalic dianhydride, ', 4,4'-benzophenonetetracarboxylic dianhydride, pyromelitic dianhydride, 1,4,5,8-naphthalenetetracarboxylic acid dianhydride, Water (1,4,5,8-Naphthalenetetracarboxylic Dianhydride), 1,2,4,5-tetracarboxylic anhydride (1,2,4,5-Tetracarboxylic Anhydride), methylnorbornene-2,3-dicarboxylic acid anhydride Methylnorbonene-2,3-dicarboxylic anhydride, 4,4 '- [2,2,2-trifluoro-1- (trifluoromethyl) ethylidene] diphthalic anhydride (4,4' - [2,2 , 2-Trifluoro-1- (Trifluoromethyl) Ethylidene] Diphthalic Anhydride, 4,4'-Oxydiphthalic Anhydride and Ethylene Glycol Bis (Anhydro Trimellitate) AnhydroTrimelitate)) &lt; / RTI &gt; Flexible display substrate, characterized in that.