KR20160082344A - Flexible orgaic light emitting diodes devices and Manufacturing method thereof - Google Patents

Abstract

The present invention relates to a flexible organic light emitting diode (OLED) device, and a manufacturing method thereof. More particularly, the flexible OLED device is an OLED substrate material which secures physical properties such as low voltage, high efficiency, and high color purity by adopting particular aramid, and a particular material as a planarization layer. The flexible OLED device comprises a substrate layer containing at least one type selected among a meta-aramid paper, a para-aramid paper, and a meta-para aramid paper.

Description

[0001] Flexible OLED device and manufacturing method thereof [0002]

The present invention relates to an OLED device, and more particularly, to a flexible OLED device in which an aramid paper is introduced into a substrate layer and a specific material is introduced into a planarization layer, and a method of manufacturing the same.

In recent years, interest and research on smart wear have been increasing. Smart apparel means functional clothing capable of embodying digital functions by combining electric and electronic materials while maintaining the properties of textiles and clothing, It has been developed for military use, and is currently undergoing research and investment to expand its application to the clothing and medical fields. For example, clothing electronics can be used to combine clothing with wearable computers.

In addition, with regard to display in recent years, development of a flexible display capable of folding, bending, and speaking is demanded because people desire a larger screen with ease of portability. Flat panel displays such as OLEDs and LCDs require an active matrix drive method for high resolution and low power operation. Inorganic thin film transistors, such as silicon currently used, have a high manufacturing temperature and break easily when bent or bent. There is a limit to apply.

As described above, in order to provide flexible electric and electronic products such as smart clothes and flexible displays, researches on organic thin film transistors (OTFTs) and OLED devices that can withstand bending or bending have been actively conducted .

As an organic thin film transistor (OTFT) or an organic light emitting diode (OLED) device, an organic semiconducting material is dissolved in a solvent to form a thin film by a variety of coating methods. Organic semiconductors that can not dissolve in a solvent and form a thin film by sublimating organic semiconductors by applying heat in a high vacuum device. The method that can apply the organic semiconductor thin film by the solution process has a lower manufacturing cost than the vacuum evaporation method and has recently been actively studied because it is possible to perform a roll to roll continuous process on a flexible substrate by various coating methods.

In the roll-to-roll process, the flexible organic thin film transistor can be mass-produced at a lower cost. However, for this purpose, it is necessary to use substrates such as plastic or stainless steel which can be rolled up to a temperature of 300 ° C. or less, or a material excellent in flexibility and electrical properties There is a problem in that it is necessary to introduce the system. Conventionally, films and fibers of PET materials have been introduced as substrates for organic thin film transistors and / or OLED devices. However, there is a limit in that heat resistance is insufficient.

U.S. Registration No. US 6,107,117 (published on August 22, 2000) Korea Open Patent KR 2012-0021023 (public date March 23, 2012)

DISCLOSURE OF THE INVENTION The inventors of the present invention have studied to solve the limit of heat resistance which is a problem of conventional flexible OLED devices. As a result, the present inventors have found that when the aramid paper is introduced as a substrate and the aramid paper is introduced for improving heat resistance, To provide a novel flexible OLED device capable of securing heat resistance and excellent electrical and optical characteristics by forming a two-layer planarization layer of a specific material in order to minimize and /

Disclosure of the Invention In order to solve the above-described problems, the present invention relates to a flexible OLED device, and more particularly, to a flexible OLED device comprising a substate layer containing at least one selected from the group consisting of meta-aramid paper, para-aramid paper and meta-para-aramid paper; And a planarization layer (not shown).

In one preferred embodiment of the present invention, the meta-aramid paper has an apparent density of 0.20 to 0.40 g / cm 3 and a thickness of 60 to 130 탆 measured according to ASTM D-828, Directional tensile strength of 25 N / cm or more, elongation in the MD direction of 5.0% or more, and tear strength in the MD direction measured according to TAPPI T414 of 0.95 N or more.

In one preferred embodiment of the present invention, the meta-aramid paper as the material of the base layer has a tear strength in the MD direction of 20 to 30 Nm 2 / kg when the thickness is 0.14 mm, The paper may have a basis weight of 35 to 50 g / m 2.

In one preferred embodiment of the present invention, the meta-aramid paper as a material of the base layer includes meta-aramid floc and meta-amide fibrids, and the floc and fibrids have an intrinsic viscosity (IV) of 1.5 to 2.0 .

As a preferred embodiment of the present invention, in the flexible OLED device of the present invention, the planarization layer has a single layer structure, such as PMF (polyamine-co-formaldehyde), poly (4-vinylphenol) glycol monomethyl ether acetate (PEGDMA), polypropylene glycol dimethacrylate (PPGDMA), polypropylene glycol diacrylate (PPGDA), poly diethylene glycol diacrylate (PDEGDA), POSS compounds represented by the following formula 2, and a polysilazane-based compound represented by the following general formula (1).

As a preferred embodiment of the present invention, the flattening layer of the flexible OLED device according to the present invention is a multi-layered structure including PMF, PVP, PGMEA, PEGDMA, PPGDMA, PPGDA, PDEGDA, POSS- A first planarization layer comprising at least one selected from a silazane-based compound and a polysilazane-based compound represented by the following formula (2); And a second planarization layer comprising a polymer represented by the following formula (3).

[Chemical Formula 1]

,

또는

이고, R¹, R³ 및 R⁴는 각각은 독립적인 것으로서, 탄소수 2 ~ 5의 알킬렌기이며, R²는 수소원자 또는 탄소수 1 ~ 5의 알킬기이고, X는 -NHR⁵이고, 상기 R⁵는 수소원자 또는 탄소수 1 ~ 5의 알킬기이며,In Formula 1, E is

,

or

And, R ^1, R ³ And Each of R ⁴ is independently an alkylene group having 2 to 5 carbon atoms, R ² is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, X is -NHR ⁵ , R ⁵ is a hydrogen atom, Lt; / RTI >

(2)

In Formula 2, R < ^{1 >} To R ⁹ Each independently represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, B is -NHR ¹⁰ , and R ¹⁰ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.

(3)

In the general formula (3), R &^lt; ¹ > Each R ⁸ is independently a hydrogen atom, a halogen atom, a carboxyl group, an amide group, -CF ₃ , -Si (OR) _m H _3-m , a formyl group or N is an rational number satisfying a weight average molecular weight of 50,000 to 200,000, and m is an integer of 0 to 3.

In one preferred embodiment of the present invention, the flexible OLED device of the present invention may have the base layer, the first planarization layer, and the second planarization layer stacked in order.

In one preferred embodiment of the present invention, the polysilazane as the material of the first planarizing layer is a polymer of a monomer represented by the following formula 4-1; A copolymer comprising a compound represented by the following formula (4-1) and a compound represented by the following formula (4-2); And a polymer represented by the following formula (4-3).

[Formula 4-1]

In Formula 4-1, R ¹ and R ² are each independently a hydrogen atom or an alkyl group having 1 to 3 carbon atoms,

[Formula 4-2]

In Formula 4-2, R ¹ is an alkyl group having 1 to 3 carbon atoms,

[Formula 4-3]

In Formula 4-3, R ¹ is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, R ² is an alkylene group having 2 to 5 carbon atoms, R ³ and R ⁴ are independently a hydrogen atom, An alkyl group having 1 to 3 carbon atoms or an alkoxy group having 1 to 3 carbon atoms, and R ⁵ is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.

In one preferred embodiment of the present invention, the polysilazane based compound may include a copolymer obtained by copolymerizing the monomer represented by Formula 4-1 and the monomer represented by Formula 4-2 at a molar ratio of 1: 2 to 6 have.

In one preferred embodiment of the present invention, the first planarization layer is formed of a dimethacrylate-based compound containing at least one selected from the group consisting of PEGDMA (Polyethylene glycol dimethacrylate) and PPGDMA (Polypropylene glycol dimethacrylate); And a mixture containing the POSS compound, the silazane and the polysilazane in a weight ratio of 1: 0.1 to 1.5.

In one preferred embodiment of the present invention, the first planarizing layer and the second planarizing layer may be formed to have a thickness ratio of 1: 0.1 to 100.

In a preferred embodiment of the present invention, the flexible OLED device of the present invention is characterized in that the substrate layer has an average thickness of 0.1 m to 150 m, and the planarization layer has an average thickness of 0.1 m to 10 m.

In a preferred embodiment of the present invention, in the flexible OLED device of the present invention, the planarization layer has a root mean square surface roughness (RMS) of 0.1 nm to 300 nm.

As a preferred embodiment of the present invention, the flexible OLED device of the present invention has a structure in which the base layer, the planarization layer, the anode layer, the hole injection-transport layer, the light emitting layer, the electron transport layer, the electron injection layer, .

In addition, as a preferred embodiment of the present invention, the flexible OLED device of the present invention may further include a capping layer between the anode layer and the hole injecting-transporting layer, and further includes a capping layer on the upper surface of the cathode layer It is possible.

In one preferred embodiment of the present invention, the light emitting layer includes a host and a dopant, and the host includes CBP (4,4'-Bis ( N- carbazolyl) -1,1'-biphenyl) Ir (ppy) ₃ ) (Tris [2-phenylpyridinato-C ² , N ] iridium (III)).

In one preferred embodiment of the present invention, the electron transport layer is made of TPBi ( N, N' -Di (1-naphthyl) -N, N'-diphenyl- (1,1'- And a control unit.

In one preferred embodiment of the present invention, the capping layer may include TAPC (Di- [4- (N, N-ditolyl-amino) -phenyl] cyclohexane.

In a preferred embodiment of the present invention, the flexible OLED device of the present invention has a current density of 0.1 to 0.2 mA / cm 2 and a luminance of 50 cd / m 2 when the voltage is 3.0 V to 6.0 V, M < 2 > to 100 cd / m < 2 >.

Further, as a preferred embodiment of the present invention, the flexible OLED device of the present invention has an external quantum efficiency (EQE) of 3% to 20% when the current density is 0.1 mA / cm 2 to 0.2 mA / . ≪ / RTI >

Further, as a preferred embodiment of the present invention, the flexible OLED device of the present invention can have a PL wavelength intensity of 4 to 95 (arb. Unit) when measuring an electroluminescence spectrum.

Another object of the present invention is to provide a method of manufacturing flexible OLED devices of various types described above, wherein a planarization layer is formed on one surface of a substrate of an aramid material, and then an OLED device is formed.

As a preferred embodiment of the present invention, the method for producing a flexible OLED device according to the present invention is a method for producing a flexible OLED device, which comprises applying a PMF, a PVP, or a polyvinylidene fluoride (PVP) on one side of a substrate of an aramid paper material containing at least one selected from meta-aramid paper, para- aramid paper and meta-para- , PGMEA, PEGDMA, EGDMA, PPGDA, a POSS compound represented by the following formula (1), a silazane represented by the following formula (2), and polysilazane are coated and dried to form a flattening layer ; And a step of sequentially depositing an anode layer, a cathode layer, a hole injecting-transporting layer, a light emitting layer, an electron transporting layer, an electron injecting layer, and a cathode layer on the upper surface of the planarizing layer to fabricate a flexible OLED device have.

[Chemical Formula 1]

,

또는

이고, R¹, R³ 및 R⁴는 각각은 독립적인 것으로서, 탄소수 2 ~ 5의 알킬렌기이며, R²는 수소원자 또는 탄소수 1 ~ 5의 알킬기이고, X는 -NHR⁵이고, 상기 R⁵는 수소원자 또는 탄소수 1 ~ 5의 알킬기이며,In Formula 1, E is

,

or

And, R ^1, R ³ And Each of R ⁴ is independently an alkylene group having 2 to 5 carbon atoms, R ² is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, X is -NHR ⁵ , R ⁵ is a hydrogen atom, Lt; / RTI >

(2)

In Formula 2, R < ^{1 >} To R ⁹ Each independently represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, B is -NHR ¹⁰ , and R ¹⁰ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.

In a preferred embodiment of the present invention, the step of forming the planarization layer comprises the steps of: forming a planarization layer on the substrate by depositing PMF, PVP, PGMEA, PEGDMA, PPGDMA, PPGDA, PDEGDA, a POSS compound represented by the following formula Coating and drying a first planarization resin comprising at least one selected from the group consisting of silazane and polysilazane to form a planarization layer; And forming a second planarization layer by coating and drying a second planarization resin comprising a polymer represented by the following formula (3) on the upper surface of the first planarization layer to form a planarization layer as a multi-layer structure .

(3)

In the general formula (3), R &^lt; ¹ > Each R ⁸ is independently a hydrogen atom, a halogen atom, a carboxyl group, an amide group, -CF ₃ , -Si (OR) _m H _3-m , a formyl group or N is an rational number satisfying a weight average molecular weight of 50,000 to 200,000, and m is an integer of 0 to 3.

In one preferred embodiment of the present invention, the aramid paper used as a base material is manufactured by performing a process that does not include a calendering process, wherein the aramid paper comprises a meta-aramid flock and a meta- (1) a wet-web; A second step of dewatering the wet paper; A third step of drying the dehydrated wet paper by a first hot air blow; A fourth step of drying the dried wet paper by secondary drying to produce paper; And a fifth step of tertiary drying the dried paper at 250 ° C to 320 ° C.

As a preferred embodiment of the present invention, in the production of the aramid paper, the first hot air drying may be performed by hot air drying at 195 ° C to 250 ° C.

As a preferred embodiment of the present invention, the secondary drying may be performed at 100 ° C to 150 ° C during the production of the aramid paper, and the tertiary drying may be performed for 10 seconds to 80 seconds.

As a preferred embodiment of the present invention, the method may further include compressing and dewatering the wet paper between the steps 2 and 3 or between the steps 3 and 4 at the time of producing the aramid paper.

The flexible OLED device of the present invention uses a substrate of an aramid paper material to secure flexibility and thus can provide a flexible OLED-based wearable display, a rollable display, a wearable lighting device, It is possible to prevent the degradation of the electrical and optical characteristics due to the introduction of the substrate of the aramid paper material by introducing a specific material into the planarizing layer. Therefore, a flexible OLED element having excellent electrical and optical characteristics and a device using the same can be provided .

Fig. 1 shows a schematic view of a process for producing an aramid paper in Preparation Example 1-1.
2 is a schematic view of a flexible OLED device of the present invention.
3 is an AFM measurement photograph of the RMS surface roughness of the planarization layer of the flexible OLED device of Example 1 performed in Experimental Example 1. FIG.
4 is an AFM measurement photograph of the RMS surface roughness of the planarizing layer of the flexible OLED device of Example 8 and Comparative Example 5 conducted in Experimental Example 1. [
FIG. 5 is a graph showing the electroluminescence spectra of the flexible OLED devices of Example 8 and Comparative Example 5 performed in Experimental Example 2. FIG.
6 is a graph showing electroluminescence spectra of flexible OLED devices of Examples 2, 6, Comparative Example 1, Comparative Example 3, and Comparative Example 4 conducted in Experimental Example 2. FIG.
7 is a graph showing the external quantum efficiency (EQE) measurement of the flexible OLED device of Example 8 and Comparative Example 5 performed in Experimental Example 3. FIG.
FIG. 8 is a graph of external quantum efficiency (EQE) measurement of Example 3, Comparative Example 1 and Comparative Example 4 performed in Experimental Example 3. FIG.
9 is a graph of luminance (cd / m ² ) measurement of Example 3, Comparative Example 1 and Comparative Example 4 conducted in Experimental Example 3. FIG.

The term "film" used in the present invention has a broad meaning including not only the film form commonly used in the art but also a sheet form and a coating form.

The term " C1 ", "C2 ", etc. used in the present invention means a carbon number. For example," C1 to C5 alkyl "means an alkyl group having 1 to 5 carbon atoms.

로 표현된 화학식에서, [R₁은 독립적으로 수소원자, 메틸기 또는 에틸기이며, a는 1 ~ 3이다.]라고 치환기에 대해 표현되어 있을 때, a가 3인 경우, 복수의 R¹, 즉 R¹ 치환기가 3개가 있고, 이들 복수 개의 R¹들 각각은 서로 같거나 다른 것으로서, R¹들 각각은 모두 수소원자, 메틸기 또는 에틸기일 수 있으며, 또는 R¹들 각각은 다른 것으로서, R¹ 중 하나는 수소원자, 다른 하나는 메틸기 및 또 다른 하나는 에틸기일 수 있음을 의미하는 것이다. 그리고, 상기 내용은 본 발명에서 표현된 치환기를 해석하는 일례로서, 다른 형태의 유사 치환기도 동일한 방법으로 해석되어야 할 것이다.In the present invention

A in the formula, expressed by [and R ₁ independently represent a hydrogen atom, a methyl group or an ethyl group, a is 1 to 3 a.] That when the representations of the substituent, and when a is 3, the plurality of R ^1, i.e., R ^One As there are three substituents, each of a plurality of R ¹ which are the same or different, R ¹ in each of both may be a hydrogen atom, methyl or ethyl, or R ¹ as each of the other, R ¹ One of Hydrogen atom, the other is a methyl group, and the other is an ethyl group. The above is an example of interpreting the substituent represented by the present invention, and other similar substituents should also be interpreted in the same way.

As used herein, the term "flock" refers to fibers of shorter length than staple fibers, the flock length is from about 0.5 mm to about 15 mm, the diameter is from 4 to 50 μm, 1 mm to 12 mm and a diameter of 8 to 40 탆. Aramid floc can be produced by cutting aramid fibers to short lengths without significant or optional fibrillization, such as those produced by the methods described in U.S. Patent Nos. 3,063,966, 3,133,138, 3,767,756 and 3,869,430 . In addition, the term "fibrids " as used herein means non-granular pulp or film-like particles, preferably the melting point or decomposition point thereof may exceed 320 ° C. The fibrids have an average length of 0.5 mm to 2 mm and an aspect ratio of 15: 1 to 50: 1. Including the use of a fibridation apparatus of the type disclosed in U.S. Patent No. 3,018,091, and any method in which the polymer solution is precipitated and sheared in a single step.

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

In the present invention, as a base layer, an aramid paper is introduced to enable the flexibility of an OLED element, and a specific material is used to prevent the electric characteristics of the OLED element from being degraded due to the surface roughness due to a base material layer of a paper substrate And is introduced into the planarizing layer.

The flexible OLED element of the present invention can introduce the substrate layer and the planarization layer into various types of flexible OLED elements. For example, the substrate layer 10, the single-layered planarization layer The anode layer 30, the hole injection-transport layer 40, the light-emitting layer 60, the electron transport layer 70, and the cathode layer 90 may be laminated, or alternatively, The planarization layer 20, the anode layer 30, the hole injection-transport layer 40, the light-emitting layer 60, the electron transport layer 40, and the electron transport layer 40, which are constituted by the substrate layer 10, the first planarization layer 21 and the second planarization layer 22, The transport layer 70 and the cathode layer 90 may be laminated. Alternatively, capping layers 50 and 50 'may be introduced between the hole injection-transport layer 40 and the light emitting layer 60 and / or the top surface of the cathode layer 90.

In the present invention, the base layer may include at least one aramid paper selected from the group consisting of meta-aramid paper, para-aramid paper and meta-para-aramid paper. Preferably, the meta-aramid paper may be used as a substrate layer material. The base layer preferably has an average thickness of 0.1 占 퐉 to 150 占 퐉, preferably 0.1 占 퐉 to 100 占 퐉, more preferably 0.2 占 퐉 to 80 占 퐉, wherein the average thickness of the base layer is 0.1 占 퐉 , There may be a problem that the paper tears. When the thickness exceeds 150 mu m, the flexibility of the OLED element may be deteriorated. Therefore, it is preferable that the thickness is within the above range.

When the meta-aramid paper is used as the substrate layer material, the meta-aramid paper preferably has a bulk density of 0.20 g / cm 3 to 0.40 g / cm 3 and a thickness of 60 μm to 130 탆, a tensile strength in the MD direction of 25 N / cm or more, preferably 25 N / cm to 35 N / cm, an elongation in the MD direction of 5.0% or more, preferably 5.0% to 10.0%, and a TAPPI T414 , A tear strength in the MD direction of 0.95 N or more, preferably 1.00 N to 1.20 N, can be used. Also, the meta-aramid paper has a tensile strength in the MD direction of 20 Nm 2 / kg to 30 Nm 2 / kg, preferably a non-drawn strength of 22 Nm 2 / kg to 28 Nm 2 / kg when the thickness is 0.14 mm And the meta-aramid paper may have a basis weight of 35 g / m2 to 50 g / m2, preferably 38 g / m2 to 45 g / m2. The meta-aramid paper includes meta-aramid floc and meta-amide fibrids, and the floc and fibrids have an intrinsic viscosity (IV) of 1.5 to 2.0.

A method for producing an aramid paper which is a base layer component will be described below.

More specifically, FIG. 1 is a process diagram for a method of manufacturing an aramid paper according to an embodiment of the present invention.

A first step of preparing a wet-web by inputting a feedstock containing aramid floc and amarylated fibrids; A second step of dewatering the wet paper; A third step of drying the dehydrated wet paper by a first hot air blow; A fourth step of secondary drying the dried wet paper; And 5 steps of drying the dried paper at a temperature of from 250 to 320 DEG C for three times to prepare an aramid paper.

In the step of preparing the wet paper, the aramid flock and the aramid fibrid may be prepared from meta-aramid floc and meta-aramid fibrids when preparing the meta-aramid paper. The amount of the meta-aramid flake may be 80 to 200 parts by weight based on 100 parts by weight of the meta-aramid flock.

Meta-aramid polymers suitable for use in meta-aramid fibrids and meta-aramid flocs may be polyamides in which at least 85% of the amide (-CO-NH-) linkages are attached directly to the two aromatic rings, , Up to 10% by weight of many other polymeric materials can be blended with the meta-aramid. As a specific example, a copolymer having 10% of diacid chloride replacing the diamine of the aramid may be used. And, the meta-aramid polymer may be a polymer of poly (metaphenylene isophthalamide), 4,4-diaminodiphenyl sulfone and / or 3,3-diaminodiphenyl sulfone, preferably poly Phenylene isophthalamide). ≪ / RTI >

On the other hand, the intrinsic viscosity (IV) of the meta-aramid polymer contained in the meta-aramid fibrids and the meta-aramid flocs is 1.5 to 2.0, which improves the physical properties of the paper in relation to the primary hot air drying, the secondary drying and the tertiary drying It is very advantageous. If the intrinsic viscosity (I.V) of the meta-aramid polymer is less than 1.5 or more than 2.0, the degree of improvement of physical properties will be remarkably deteriorated.

On the other hand, in step 1, a refiner can be manufactured by mixing aramid floc and aramid fibrids in water using a refiner (Refiner: 100). The aramid floc and fibrids may be 1 to 10% by weight based on the total groundbreaking composition, but are not limited thereto. The material passing through the defuzzifier 100 is conveyed to the wire part 210 through the head box 120. The gold net 210 is formed by a fourdrinier machine formed in endless form, a cylinder machine having a large cylindrical shape, an inclinable machine, and a net net formed up and down. And a gap former, which can be used without limitation in the present invention. Specifically, the material discharged from the head box 120 forms a wet web through the forming board 211 of the gold net.

Next, in step 2, the wet paper is dehydrated. The wet paper is fed by a plurality of rollers provided in the gold net 210, and the dehydration process is performed while passing through the dehydrating part 212. The dewatering unit may be achieved through a suction box, and the suction box may include a plurality of suction boxes. The suction box is installed so as to be in contact with the bottom of the net, and the dewatered water is discharged to the outside of the net.

Next, in step 3, the dehydrated wet paper is subjected to a primary hot air drying in a hot air drying unit 220. The above step 3 is performed in order to increase moisture removal of the wet paper web and minimize the thickness reduction of the wet paper web structure The physical properties such as bulk, air permeability and absorbency are improved as compared with the paper which is not subjected to this. The third step is advantageously performed at a temperature of 195 ° C to 250 ° C. If the hot air drying is performed outside the temperature range, the degree of property improvement may become insignificant. In addition, the third step must be accomplished through hot air drying. Examples of the hot air dryer include a through air dryer, a spooner, and the like. If a dryer other than hot air drying is used (for example, Cylinder Dryer, Yankee Dryer, Lab water drier, etc.), the moisture in the paper remains in the form of pockets, And the thickness of the wet paper is reduced as the wet paper is dried by the dry felt, and it may be difficult to achieve the object of the present invention even when the temperature condition is satisfied.

According to another preferred embodiment of the present invention, the method may further include compressing and dewatering the wet paper between the second and third steps or between the third and fourth steps in the compressing / dehydrating unit 230. In this case as well, the compression dehydration can be selectively carried out in the case where the density of the meta-aramid paper satisfies the low density range.

Next, as the fourth step, the hot-air dried wet paper is subjected to secondary drying in the secondary drying unit 240 to produce paper. This is to effectively remove moisture from wet paper pellets, and the drying temperature may be from 100 ° C to 150 ° C. If the drying temperature is less than 100 ° C, drying may not be performed as desired, and drying problems may occur. If the drying temperature exceeds 150 ° C, the moisture inside the wet paper filter may remain in the form of a pocket due to rapid drying. The drying time may be from 30 seconds to 600 seconds.

Next, in step 5, the hot air-dried paper is thirdly dried in a tertiary drying part 250 at 250 ° C to 320 ° C. Conventional aramid paper did not go through steps 3 and 5, but merely obtained a four-step drying process at 100 ° C to 150 ° C. As a result, it was confirmed that elongation and tear strength were remarkably improved compared to conventional aramid paper while keeping low density because calendering was not performed. Specifically, the tertiary drying is carried out at 250 ° C to 320 ° C, which is very advantageous in improving the physical properties. If the tertiary drying temperature is lower than 250 ° C or exceeds 320 ° C, it is difficult to satisfy desired properties. Meanwhile, the tertiary drying may be performed for 10 seconds to 80 seconds. If it is less than 10 seconds, it is difficult to achieve the desired purpose, and if it exceeds 80 seconds, the flexibility of the paper can be reduced, which may cause problems in workability of the product.

As described above, the planarization layer of the present invention is formed on the upper surface of the substrate layer, and has a single layer structure or a multi-layer structure as schematically shown in Fig. 2, in which the planarization layer 20 includes a first planarization layer 21, And a second planarization layer (22).

When the planarization layer 20 has a single-layer structure, the PMF (poly (4-vinylphenol), PGMEA (poly ethylene glycol dimethacrylate), PEGDMA (poly ethylene glycol dimethacrylate) (PPGDA), polyglycol dimethacrylate (PPGDA), poly (ethylene glycol diacrylate) (PPGDA), poly diethylene glycol diacrylate (PDEGDA) A planarizing layer can be formed using a resin mixed with two or more kinds of resins.

When the flattening layer is formed in a multi-layered structure, the first flattening layer may be formed of at least one of PMF, PVP, PGMEA, PEGDMA, PPGDMA, PPGDA, PDEGDA, a POSS compound represented by the following Chemical Formula 1, A compound and a polysilazane compound, preferably a dimethacrylate compound containing at least one selected from the group consisting of PEGDMA and EGDMA; And a mixture containing at least one selected from the POSS compound, the silazane compound and the polysilazane compound, and more preferably the dimethacrylate compound; And the above-mentioned mixture in a weight ratio of 1: 0.1 to 1.5, preferably 1: 0.2 to 1.2, more preferably 1: 0.5 to 1.2, is advantageous in terms of flexibility and heat resistance.

[Chemical Formula 1]

,

또는

이고, 바람직하게는

또는

이다. 그리고, 상기 R¹, R³ 및 R⁴ 각각은 독립적인 것으로서, 탄소수 2 ~ 5의 알킬렌기이며, 바람직하게는 탄소수 2 ~ 3의 알킬렌기이다. 또한, 상기 R²는 수소원자 또는 탄소수 1 ~ 5의 알킬기이고, 바람직하게는 탄소수 1 ~ 3의 알킬기, 더욱 바람직하게는 탄소수 1 ~ 2의 알킬기이다. 그리고, 상기 X는 -NHR⁵이고, 상기 R⁵는 수소원자 또는 탄소수 1 ~ 5의 알킬기이며, 바람직하게는 수소원자이다.In Formula 1, E is

,

or

, And preferably

or

to be. The above R ¹ and R ³ And Each R ⁴ is independently an alkylene group having 2 to 5 carbon atoms, preferably an alkylene group having 2 to 3 carbon atoms. R ² is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, preferably an alkyl group having 1 to 3 carbon atoms, more preferably an alkyl group having 1 to 2 carbon atoms. X is -NHR ⁵ , and R ⁵ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, preferably a hydrogen atom.

(2)

In Formula 2, R < ^{1 >} To R ⁹ Each independently represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, preferably a hydrogen atom. B is -NHR ¹⁰ , R ¹⁰ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and preferably R ¹⁰ is a hydrogen atom or an alkyl group having 1 to 2 carbon atoms.

The polysilazane compound may be a polymer of a monomer represented by the following formula (4-1); A copolymer comprising a compound represented by the following formula (4-1) and a compound represented by the following formula (4-2); And a polymer represented by the following formula (4-3), preferably a copolymer comprising a compound represented by the following formula (4-1) and a compound represented by the following formula (4-2) And more preferably a copolymer obtained by copolymerizing the monomer represented by Formula 4-1 and the monomer represented by Formula 4-2 at a molar ratio of 1: 2 to 6.

[Formula 4-1]

In Formula 4-1, R ¹ and R ² are each independently a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, preferably a hydrogen atom or an alkyl group having 1 carbon atom.

[Formula 4-2]

In the formula (4-2), R ¹ is an alkyl group having 1 to 3 carbon atoms, preferably an alkyl group having 1 carbon atom.

[Formula 4-3]

In Formula 4-3, R ¹ is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, preferably an alkyl group having 1 carbon atom. R ² is an alkylene group having 2 to 5 carbon atoms, preferably an alkylene group having 2 to 3 carbon atoms. R ³ and R ⁴ are independently a hydrogen atom, an alkyl group having 1 to 3 carbon atoms or an alkoxy group having 1 to 3 carbon atoms, preferably an alkoxy group having 1 to 3 carbon atoms. And R ⁵ is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, preferably an alkyl group having 1 carbon atom.

The planarization layer of the present invention may improve the surface roughness and improve the external quantum efficiency (EQE) by introducing a second planarization layer containing a specific material on the upper surface of the first planarization layer .

In the present invention, the second planarizing layer may include a polymer represented by the following formula (3).

(3)

In the general formula (3), R &^lt; ¹ > Each R ⁸ is independently a hydrogen atom, a halogen atom, a carboxyl group, an amide group, -CF ₃ , -Si (OR) _m H _3-m , a formyl group or An acyl group is preferable, and R &^lt; ¹ > to R &^lt; Each R < ⁸ > is independently a fluorine atom, a chlorine atom or a formyl group, more preferably R &^lt; Each R < ⁸ > is a fluorine atom. The polymer represented by the formula (3) is a rational number satisfying a weight average molecular weight of 50,000 to 200,000, preferably a rational number satisfying a weight average molecular weight of 70,000 to 150,000. M is an integer of 0 to 3, preferably an integer of 2 to 3, more preferably 3.

The planarization layer may have a total average thickness of 0.1 to 10 mu m, preferably an average thickness of 0.2 to 5 mu m, more preferably 0.2 to 1 mu m. If the total thickness of the planarization layer including the first planarization layer and the second planarization layer is less than 0.1 탆, the surface roughness may increase to affect the electrical characteristics of the OLED device. If the total thickness of the planarization layer is 10 탆 It is not necessary to increase the thickness.

In addition, in the planarizing layer, the first planarizing layer and the second planarizing layer may be formed to have a thickness ratio of 1: 0.1 to 10, wherein the second planarizing layer has a thickness ratio of 1: 0.1 If the thickness is too thin, the effect of reducing the surface roughness may be deteriorated. In order to form the second planarizing layer at a 1: 10 thickness ratio, the second planarizing layer is formed unnecessarily too thick. Layer and the second planarization layer.

In the case of forming a single planarization layer and / or a plurality of first planarization layers and a second planarization layer on the upper surface of the substrate layer as described above, in the present invention, the surface roughness of the planarization layer is 0.1 nm to 300 nm, Preferably from 1 nm to 100 nm, and more preferably from 2 nm to 50 nm.

As described above, the OLED device of the present invention includes a substrate layer 10, a single-layer planarization layer 20, an anode layer 30, a hole injection-transport layer 40, a light emitting layer 60, an electron transport layer 70, A cathode layer 90 and a planarization layer 20 preferably composed of a base layer 10, a first planarization layer 21 and a second planarization layer 22, a cathode layer 30 A hole injecting-transporting layer 40, a light emitting layer 60, an electron transporting layer 70, and a cathode layer 90 may be stacked.

Alternatively, capping layers 50 and 50 'may be introduced between the hole injection-transport layer 40 and the light emitting layer 60 and / or the top surface of the cathode layer 90.

The anode layer 30 may be made of a common electrode material used in the related art. For example, aluminum (Al) and / or silver (Ag) may be used as the anode layer 30 under high vacuum of 5 × 10 ^-6 torr or less. The anode layer can be formed by a vacuum thermal deposition method at a rate of Å / s to 5 Å / s.

The hole injecting and transporting layer 40 may be formed using a general material used in the related art. For example, molybdenum oxide (MoO ₃ ) and TAPC (Di- [4- (N, N-ditolyl -amino) -phenyl] cyclohexane was subjected to vacuum thermal deposition at a rate of 0.5 Å / s to 1 Å / s under a high vacuum of 5 × 10 ^-6 torr or less to deposit the hole injection- It can be formed with a thickness of 300 nm.

The light emitting layer 60 may be formed using a general material used in the related art. For example, CBP (4,4'-Bis ( N- carbazolyl) -1,1'-biphenyl ) And Ir (ppy) ₃ ) (Tris [2-phenylpyridinato-C ² , N ] iridium (III)) as a dopant at a high vacuum of 5 × 10 ^-6 torr or less at 0.5 Å / s to 1 Å / The light emitting layer can be formed to a thickness of 20 nm to 50 nm.

The electron transport layer 70 may also be formed using a general material used in the art. For example, TPBi ( N, N' -Di (1-naphthyl) -N, N'- diphenyl- 1,1'-biphenyl) -4,4'-diamine at a rate of 0.5 Å / s to 1 Å / s under high vacuum of 5 × 10 ^-6 torr or less to simultaneously form the electron transport layer at 20 to 80 nm Thickness.

Also, the cathode layer 90 may be formed using a general material used in the related art. For example, the cathode layer 90 may be formed using aluminum and / or silver (Ag) ^At a high vacuum of ^-6 torr or less, aluminum is thermally deposited at a rate of 2 A / s to 5 A / s to form an aluminum layer having a thickness of 1 to 5 nm, and silver is deposited on the upper surface of the aluminum layer at a rate of 2 A / s A silver (Ag) layer having a thickness of 10 to 20 nm may be formed at a rate of about 2.5 A / s to form a two-layered negative electrode layer.

Also, a resin including TAPC (Di- [4- (N, N-ditolyl-amino) -phenyl] cyclohexane is vacuum- deposited to form a hole between the hole injecting-transporting layer 40 and the light emitting layer 60 and / Capping layers 50 and 50 'are formed on the upper surface of the cathode layer 90 to adjust the optical resonance of the light emitting layer, that is, to match the refractive index with the internal organic layer, And the like.

Hereinafter, the present invention will be described in more detail with reference to the following examples. However, the following examples should not be construed as limiting the scope of the present invention, and should be construed to facilitate understanding of the present invention.

[ Example ]

Preparation Example  1-1: Aramid  Manufacture of paper

(Meta-aramid fibrid) dope (mA dope) having an intrinsic viscosity of 1.8 was prepared, and a meta-aramid fibrid with 150 ml of Canadian Standard Freeness was prepared using a fibril production apparatus. . The prepared fibrids were adjusted to a concentration of 0.8% using a double disk refiner to improve the processability of the wet nonwoven fabric and to improve the physical properties of the final product, thus adjusting the freeness of the fibrids to 80 ml.

On the other hand, after 2.0 denier fibers were produced by using the same polymer, floc was prepared by cutting the fiber length to 7 mm. The strength of the flock was 5.3 g / de and elongation was 35%.

Thereafter, the fibrids and flocs were mixed in water at a weight ratio of 6: 4, and the resultant mixture was added in an amount of 0.5 wt% with respect to water to prepare a ground.

The above-mentioned materials were put into the paper manufacturing apparatus of Fig. 1 to prepare wet paper pills. Thereafter, primary hot air drying was performed at 200 ° C for 30 seconds in a hot air dryer, and secondary drying was performed at 120 ° C for 60 seconds. Then, the paper was subjected to tertiary drying at 300 ° C for 20 seconds in a cylinder dryer, (Average thickness 60 占 퐉).

Preparation Example  1-2

A meta-aramid paper was prepared in the same manner as in Preparation Example 1-1 except that the temperature of the hot air dryer was 235 DEG C and the average thickness of the meta-aramid paper was 80 mu m.

Preparation Example  1-3

A meta-aramid paper (average thickness 60 탆) was prepared in the same manner as in Preparation Example 1-1, except that a meta-aramid having an intrinsic viscosity of 1.5 was used.

Preparation Example  1-4

A meta-aramid paper was prepared in the same manner as in Preparation Example 1-1 except that a meta-aramid having an intrinsic viscosity of 2.0 was used and the average thickness of the meta-aramid paper was 80 μm.

Preparation Example  1-5

A meta-aramid paper was prepared in the same manner as in Preparation Example 1-1, except that the average thickness of the meta-aramid paper was 130 탆.

Example of comparison preparation  1-1

A meta-aramid paper was prepared in the same manner as in Preparation Example 1-1 except that the average thickness of the meta-aramid paper was 170 탆.

Example of comparison preparation  1-2

The average thickness of the meta-aramid paper was tried to be 0.07 mu m, but the paper broke and it was difficult to process.

Experimental Example  One : Aramid  Physical property measurement of paper

The properties of the aramid paper prepared in Preparation Examples 1-1 to 1-5 and Comparative Preparation Example 1-1 were measured as follows. The results are shown in Table 1 below.

(One) The tensile strength (N / cm ) And Elongation rate (%)

The tensile strength and elongation were measured according to ASTM D-828 for 24 hours under constant temperature and humidity conditions, and then the specimens were cut in the machine direction and subjected to MD (machine direction) load in a horizontal tensile strength meter. And elongation was measured by the length ratio of the specimen until the tensile failure.

(2) Phosphorus strength (N)

The tear strength was measured according to TAPPI T414 for 24 hours under constant temperature and humidity conditions. The sample was cut in the width direction and the tear strength in MD (machine direction) was measured in an Elmendorf tear strength tester.

(3) Intangible strength ( Nm ² / kg )

The non-inhaled strength was calculated by the following formula (1) using the measured basis weight and tear strength.

[Equation 1]

(Nm ² / kg) = [Tear strength (N) x 1000] / basis weight (g / m 2)

(4) Absorption amount

The amount of water absorption was measured by a Cobb tester having an area of 100 cm2 according to TAPPI T441. After the thermo-hygroscopic treatment, the weighed sample was loaded, and then 100 ml of water was poured into the tester. After 60 seconds, the unabsorbed water was discarded. After the water was removed, weighing was carried out and the amount of water absorption was calculated by the following equation (2).

&Quot; (2) "

(G / m 2) = (weight of final sample (g) - weight (g) of sample subjected to constant temperature and humidity treatment) × 100

division Basis weight
(g / m 2) thickness
(탆) surface
density
(g / cm2) MD Tensile Strength
(N / cm) MD elongation
(%) MD
Phosphorus strength
(N) MD
Non-invasive strength
(Nm ² / kg) Absorption
(g / m 2) Preparation Example 1-1 41.3 60 0.29 29.45 6.79 1.08 26.2 13.5 Preparation Example 1-2 41.6 80 0.30 29.59 7.26 1.07 25.8 13.5 Preparation Example 1-3 41.4 60 0.28 32.72 7.36 1.15 27.8 13.7 Preparation Example 1-4 42.0 80 0.28 31.03 7.14 1.13 26.9 14.1 Preparation Example 1-5 41.8 130 0.28 30.12 6.92 1.08 25.8 13.0 Comparative Preparation Example 1-1 42.0 170 0.40 36.12 7.62 1.33 28.8 16.0

Preparation Example  2 -1: Preparation of first planarization resin

96% by weight of a mixture of PEGDMA (poly ethylene glycol dimethacrylate) and a POSS compound (hybrid plastics) represented by the following formula 1-1 in a weight ratio of 1: 1 and 4% by weight of Darocur 1173 (Ciba specialty chemicals) % Were mixed, coated and UV-cured to prepare a solventless type first planarizing resin.

[Formula 1-1]

이고, R¹은 -CH₂CH₂-이고, R²는 메틸기이다.
In Formula 1, E is

, R ¹ is -CH ₂ CH ₂ -, and R ² is a methyl group.

Preparation Example  2 -2

0.1 weight ratio of PEGDMA (poly ethylene glycol dimethacrylate) and POSS compound represented by the following formula 1-2 was mixed and 98 weight% of the mixture and 2 weight% of Irgacure 250 (Ciba specialty chemicals) as a photoinitiator were mixed, Followed by UV curing to prepare a solventless type first planarizing resin.

 [Formula 1-2]

이고, R³는 -CH₂CH₂-이고, R⁴는 -CH₂-이다.
In Formula 1, E is

, R ³ is -CH ₂ CH ₂ -, and R ⁴ is -CH ₂ -.

Preparation Example  2-3

(Trade name: KION 1800) containing a compound represented by the following formula (4-1) and a compound represented by the formula (4-2) in a molar ratio of 0.8: 0.2 was prepared.

Then, PEGDMA and the polysilazane were mixed in a weight ratio of 1: 1, and 96% by weight of the mixture and 4% by weight of Darocur 1173 (Ciba specialty chemicals), a photoinitiator, were mixed and UV-cured after coating to form a first flattening resin .

[Formula 4-1]

In Formula 4-1, R ¹ is a methyl group, and R ² is a hydrogen atom.

[Formula 4-2]

In Formula 4-2, R ¹ is a methyl group.

Preparation Example  2-4

The mixture of 96% by weight of the mixture and 4% by weight of Darocur 1173 (Ciba Specialty Chemicals) as a photoinitiator was mixed with PPGDA (Polypropylene glycol diacrylate) and the POSS compound of Formula 1-1 at a weight ratio of 1: And cured to prepare a solventless type planarizing resin.

Example of comparison preparation  2-1

96 wt.% Of a trifunctional acid ester (CD9051 from SARTOMER) and 4 wt.% Of a photoinitiator Darocur 1173 (Ciba Specialty Chemicals) were mixed, coated and UV cured to prepare a solventless type of planarizing resin.

Example of comparison preparation  2-2

96% by weight of the POSS compound represented by formula 1-1 of Preparation Example 2-1 and 4% by weight of Darocur 1173 (Ciba Specialty Chemicals) as a photoinitiator were mixed, and the resultant was UV-cured to prepare a first planarization resin .

Example of comparison preparation  2-3

96% by weight of the polysilazane-based compound (trade name: KION 1800) and 4% by weight of Darocur 1173 (Ciba specialty chemicals) as a photoinitiator were prepared, coated and UV cured to prepare a first planarizing resin .

Preparation Example  3: Preparation of second planarizing resin

A second planarization resin was prepared by mixing a fluorocarbon solvent (CT-solv. 180, asahi glass) and a polymer represented by the following formula (3-1) in a volume ratio of 1: 0.5.

[Formula 3-1]

In the formula (3-1), R &^lt; ¹ > R ⁸ is a fluorine atom.

Example  One : Flexible OLED  Device fabrication (multi-layered Planarization layer )

The aramid paper prepared in Preparation Example 1-1 was fixed on the upper surface of the glass. Next, the first planarizing resin prepared in Preparative Example 2-1 was coated on the upper surface of the aramid paper and then UV-cured to form a first planarizing layer having an average thickness of 0.5 탆.

Next, the second planarizing resin prepared in Preparative Example 3 was spin-coated on the upper surface of the first planarizing layer under a condition of 2,000 rpm / 60 sec to form a second planarizing layer having an average thickness of 360 nm.

Subsequently, the anode of aluminum material was vacuum-deposited at a high speed of 3.4 Å / s to 3.5 Å / s under a vacuum of 5 × 10 ^-6 torr or less to form a 5 nm thick anode layer on the upper surface of the two planarization layers .

Next, molybdenum oxide (MoO ₃ ) and TAPC (Di- [4- (N, N-ditolyl-amino) -phenyl] cyclohexane) were added to the upper surface of the anode layer at a high vacuum of 5 × 10 ^-6 torr or less At a rate of 0.7 Å / s to 0.8 Å / s to form a hole injection-transport layer with a thickness of 150 nm.

Subsequently, CBP (4,4'-Bis ( N- carbazolyl) -1,1'-biphenyl) was added to the upper surface of the hole injection-transport layer under high vacuum of 5 × 10 ^-6 torr or less, ppy) ₃ (Tris [2-phenylpyridinato-C ² , N ] iridium (III)) were simultaneously thermally deposited at a rate of 0.7 Å / s to 0.8 Å / s to form a 30 nm thick light emitting layer.

Next, under high vacuum conditions of 5 × 10 ^-6 torr or less to the upper surface of the light-emitting layer, TPBi (N, N '-Di (1-naphthyl) - N, N' -diphenyl- (1,1'-biphenyl) -4,4'-diamine at a rate of 0.7 Å / s to 0.8 Å / s to form a 40 nm thick electron transport layer.

Next, the upper surface of the electron transport layer is thermally deposited at a rate of 0.7 Å / s to 0.8 Å / s using LiF (Lithium fluoride) under a high vacuum of 5 × 10 ^-6 torr or less to form a 1 nm thick An electron injection layer was formed.

Subsequently, aluminum (Al) was vacuum deposited at a high rate of 3.4 Å / s to 3.5 Å / s under a high vacuum of 5 × 10 ^-6 torr or less to form an aluminum layer with a thickness of 1 nm, Silver (Ag) at 2.2 Å / s to 2.4 Å / s to form an Ag layer with a thickness of 15 nm.

Next, on the upper surface of the cathode layer The capping layer having a thickness of 45 nm is formed by thermally depositing TAPC (Di- [4- (N, N-ditolyl-amino) -phenyl] cyclohexane at a rate of 0.7 Å / s to 0.8 Å / s, .

Example  2

A flexible OLED device was fabricated in the same manner as in Example 1 except that, in the formation of the first planarization layer, the first planarization resin of Preparation Example 2-1 (POSS planarization resin of Formula 1-1) The first planarization layer (POSS planarization resin of Higgs type 1-2) prepared in Example 1 was used to fabricate a flexible OLED device.

Example  3

A flexible OLED device was fabricated in the same manner as in Example 1 except that, in the formation of the first planarization layer, the first planarizing resin of Preparation Example 2-1 (POSS-based planarization resin of Formula 1-1) A first planarization layer was formed using the first planarization resin (polysilazane-based planarization resin) prepared in Example 3 to prepare a flexible OLED device.

Example  4 ~ Example  7

A flexible OLED device was manufactured in the same manner as in Example 1 except that the meta-aramid paper of Preparation Examples 1-2 to 1-5 was used instead of the meta-aramid paper of Preparation Example 1-1, OLED devices were respectively manufactured, and Examples 4 to 7 were carried out.

Example  8

In the same manner as in Example 1, A flexible OLED device was prepared. Instead of the preparation example 2-1, the planarizing resin of Preparation Example 2-4 was coated on the upper surface of the aramid paper and then UV-cured to form a single-layer flattening layer having an average thickness of 0.54 占 퐉.

A flexible OLED device was fabricated by forming a positive electrode layer, a positive hole transporting layer, an electron transporting layer, an electron injecting layer, a negative electrode layer and a capping layer on the upper surface of the planarization layer in the same manner as in Example 1.

Comparative Example  One

A flexible OLED device was manufactured in the same manner as in Example 1 except that a glass substrate was used as a substrate instead of a base material layer of a meta-aramid paper substrate and a planarization layer was not formed.

Comparative Example  2

A flexible OLED device was manufactured in the same manner as in Example 1 except that a flexible OLED device was manufactured using the meta-aramid paper of Comparative Preparation Example 1-1, which is not a meta-aramid paper of Preparation Example 1-1, And Comparative Example 2 was carried out.

Comparative Example  3

A flexible OLED device was manufactured in the same manner as in Example 1 except that a first planarizing layer was formed using the first planarizing resin prepared in Comparative Preparation Example 2-2 as a first flattening layer material to manufacture a flexible OLED device Respectively.

Comparative Example  4

A flexible OLED device was fabricated in the same manner as in Example 1 except that a first planarizing layer was formed using the first planarizing resin prepared in Comparative Preparation Example 2-3 as a first planarizing layer material to manufacture a flexible OLED device Respectively.

Comparative Example  5

A flexible OLED device was prepared in the same manner as in Example 8 except that the POSS compound of Formula 1-1 and the trifunctional acid ester material of Comparative Preparation Example 2-1 were mixed at a weight ratio of 1: A planarization layer having a single layer structure having an average thickness of 0.55 占 퐉 was formed using the mixed planarization resin to prepare a flexible OLED device.

Comparative Example  6

A flexible OLED device was manufactured in the same manner as in Example 8 except that a base layer having an average thickness of 60 占 퐉 was produced using a polyethylene terephthalate film (manufactured by Toray Chemical Co., Ltd.) as a base layer material, Transport layer, an electron transport layer, an electron injection layer, a cathode layer and a capping layer were formed on the first planarization layer, the second planarization layer, the anode layer, the hole transport layer, the electron transport layer, the electron injection layer, the cathode layer and the capping layer.

Comparative Example  7

A flexible OLED device was manufactured in the same manner as in Example 8, except that a base layer having an average thickness of 60 mu m was produced using a material in which a polyurethane film and a PET fabric (Toray chemical) were laminated as a substrate layer material, A flexible OLED device was fabricated by forming a first planarization layer, a second planarization layer, a cathode layer, a hole-transporting layer, an electron transport layer, an electron injection layer, a cathode layer and a capping layer on the upper surface of the substrate layer.

Comparative Example  8

A flexible OLED device was manufactured in the same manner as in Example 8 except that a base layer having an average thickness of 60 μm was formed using an aramid fabric (Toray chemical, ARAWIN) as a base layer material, Transport layer, an electron transport layer, an electron injection layer, a cathode layer and a capping layer were formed on the first planarization layer, the second planarization layer, the anode layer, the hole injection-transport layer, the electron transport layer, the electron injection layer, the cathode layer and the capping layer.

Experimental Example  One : Flexible OLED  Element Planarization layer RMS  Surface roughness measurement experiment

Since the surface roughness of the planarization layer affects the electrical characteristics of the OLED element, the lower the surface roughness, the less the electrical and electronic characteristics of the OLED element are adversely affected.

The RMS surface roughness (root mean square surface roughness) of the flexible OLED devices manufactured in Examples 1 to 3 was measured. The results are shown in Table 2 below.

The surface roughness of the planarization layer of the flexible OLED device manufactured in Examples 1 and 2 was measured by AFM (Atomic Force Microscope). The results are shown in FIG. 3 (Example 1) and FIG. 4 Respectively.

The RMS surface roughness was measured using an AFM (Park Systems, XE-100) instrument. The tip was 320 kHz and 42 N / m, and the measured images were imaged using the Gwyddion program.

division Rq,
RMS Surface roughness (nm) Base thickness
(탆) Example 1 0.64 60 Example 2 0.73 60 Example 3 0.58 60 Example 4 0.82 80 Example 5 0.76 60 Example 6 0.94 80 Example 7 1.05 130 Example 8 1.57 60 Comparative Example 1 0.50 60 Comparative Example 2 3.24 170 Comparative Example 3 8.3 60 Comparative Example 4 6.29 60 Comparative Example 5 11.4 60 Comparative Example 6 0.72 60 Comparative Example 7 97 60 Comparative Example 8 152 60

As shown in Table 2, it was confirmed that the surface roughness of RMS of Examples 1 to 8 was very small, ranging from 0.58 to 1.57 nm. On the other hand, Comparative Examples 2 to 5 and Comparative Example 7 It was confirmed that Comparative Example 8 had a very high surface roughness value.

Particularly, in Examples 1 to 3, the surface roughnesses were 0.64 nm, 0.73 nm, and 0.58 nm, respectively, and it was confirmed that the surface roughness was similar to that of Comparative Example 1 (0.50) Also, the surface roughness was similar or lower than that of Comparative Example 6 of the PET film material of the film material.

Through this, it was confirmed that the surface roughness can be greatly improved by forming a planarization layer with a specific material, even though a base material having a high surface roughness is used. In addition, It is possible to minimize the electrical influence that may be caused by the substrate layer and the planarization layer of the OLED element.

Experimental Example  2 : Flexible OLED  Element Field  Luminescence spectrum measurement

The electroluminescence spectra of the flexible OLED devices of Examples 1 to 8 and Comparative Examples 1 to 8 were measured with a spectroradiometer (Minolta CS-1000), and the results are shown in Table 3 below.

division wavelength
(nm) PL wavelength intensity
(arb.units) Example 1 538 95 Example 2 542 88 Example 3 543 75 Example 4 533 90 Example 5 541 93 Example 6 544 91 Example 7 537 89 Example 8 519 60 Comparative Example 1 532 100 Comparative Example 2 522 88 Comparative Example 3 548 6 Comparative Example 4 511 4 Comparative Example 5 513 71 Comparative Example 6 537 74 Comparative Example 7 545 68 Comparative Example 8 544 7

As shown in Table 3, it can be seen that Examples 1 to 8 have a generally high PL wavelength intensity as in Comparative Example 1 using an organic substrate. However, in the case of Comparative Examples 2 to 8, it was confirmed that the PL wavelength intensity was very low as compared with the Examples.

The measured graphs of Example 1, Example 3, Comparative Example 1, Comparative Example 7, and Comparative Example 8 are shown in FIG. 5, and measurement graphs of Example 8 and Comparative Example 5 are shown in FIG.

Referring to FIG. 5, it was confirmed that Examples 1 and 2 exhibited a high PL wavelength intensity as in Comparative Example 1 using a glass substrate. However, it was confirmed that Comparative Example 7 using a polyurethane film and a PET fabric base material and Comparative Example 8 using an aramid fabric showed a very low PL wavelength intensity.

6, Example 8 in which a flat layer of a single layer was formed of PPGDA and POSS showed a higher PL wavelength intensity of about 1.5 times as compared with Comparative Example 5 in which a flat layer of a single layer was formed of a trifunctional acid ester material Respectively.

Experimental Example  3: Flexible OLED  Evaluation of current-luminance-voltage characteristics of device

In order to evaluate the current-luminance-voltage characteristics of Examples 1 to 8 and Comparative Examples 1 to 8, a KEITHLEY 236 source / measure unit (SMU) and a calibrated Si photodiode (Hamamatsu S5227-1010BQ) was used to simultaneously measure current-luminance-voltage characteristics.

The current-luminance-voltage characteristics of the flexible OLED devices of Examples 1 to 8 and Comparative Examples 1 to 8 were measured in the same manner as above, and the results are shown in Table 2 below. The current density (mA / cm 2) and the luminance (cd / m 2) in Table 3 below were measured at a current density of 0.15 mA / cm 2 under a voltage of 4.9 V. The external quantum efficiency (EQE) Shows a value measured at a current density current density of 0.15 mA / cm < 2 >.

Referring to FIG. 9, the luminance value (cd / m 2) in Table 4 is 48 cd / A when the current density is 0.15 mA / cm 2 and the CE value is the current density When divided, the luminance of 96 cd / m 2 can be obtained.

division Luminance
(cd / m 2) EQE
(%) Example 1 96 cd / ㎡ 12.4% Example 2 70.6 cd / ㎡ 7.4% Example 3 58.3 cd / ㎡ 5.1% Example 4 69 cd / ㎡ 8.7% Example 5 71 cd / ㎡ 10.8% Example 6 69 cd / ㎡ 8.5% Example 7 66 cd / ㎡ 8.3% Example 8 72 cd / ㎡ 9.2% Comparative Example 1 100 cd / m 2 13% Comparative Example 2 38 cd / ㎡ 2.8% Comparative Example 3 45 cd / ㎡ 3.2% Comparative Example 4 43 cd / ㎡ 3.1% Comparative Example 5 56 cd / ㎡ 7.0% Comparative Example 6 75 cd / ㎡ 11.3% Comparative Example 7 13 cd / ㎡ 2.1% Comparative Example 8 8 cd / ㎡ 0.75%

As shown in Table 4, it can be seen that the present invention has a very high luminance of 58 cd / m < 2 > at a current density of 0.15 mA / cm < 2 & , It is confirmed that it has a very high external quantum efficiency of 5.0% or more. However, in Comparative Examples 2 to 4 and Comparative Examples 7 and 8, low luminance of less than 45 cd / m 2 and low external quantum efficiency of 3.5% or less were obtained.

Particularly, in the case of Example 1, brightness and EQE values almost similar to those of Comparative Example 1 which is a glass substrate were shown.

The measurement results for Example 8 and Comparative Example 5 are shown in FIG. 7. As shown in FIG. 7, as the current density increases, E.Q.E. The OLED element of Example 8 has an external quantum efficiency (E.Q.E.) which is about 1.8 to 2.0% higher than that of Comparative Example 5. [

The external quantum efficiency (E.Q.E) measurement graph of Example 1, Comparative Example 1, and Comparative Example 7 shown in FIG. 8 showed very similar E.Q.E measurement results for Comparative Example 1 and Example 1 using a glass substrate. However, in the case of Comparative Example 7, the value of E.Q.E of 0.5% or less is shown, and it is confirmed that the external quantum efficiency is very low.

The results of the luminance measurement of Example 1, Comparative Example 1, and Comparative Example 7 shown in FIG. 9 were similar to those of the external quantum efficiency of FIG. 8, But Comparative Example 7 showed very low measurement results.

Through the above-described examples and experimental examples, the flexible OLED device of the present invention uses a substrate of an aramid paper material to secure flexibility, and can be used as a flexible OLED-based wearable display, a rollable display, And a specific material can be introduced into the flattening layer to prevent degradation of the electrical and optical characteristics due to introduction of the substrate of the aramid paper material. Therefore, it is possible to provide a flexible OLED device having excellent electrical and optical characteristics, It can be confirmed that the device can be used.

10: base layer 20: planarization layer 21: first planarization layer
22: second planarization layer 30: anode layer 40: hole injection-transport layer
50, 50 ': capping layer 60: light emitting layer 70: electron transporting layer
80: electron injection layer 90: cathode layer 100:
120: head box 210: gold net 211: ground plywood
212: dehydrating section 220: hot air drying section 230: compression dehydration section
240: Secondary drying unit 250: Third drying unit

Claims (28)

A substate layer containing at least one selected from meta-aramid paper, para-aramid paper and meta-para-aramid paper;
And a planarization layer;
And an organic light emitting diode (OLED) element.
The method according to claim 1, wherein the meta-aramid paper has an apparent density of 0.20 to 0.40 g / cm 3 and a tensile strength in the MD direction of 25 N / cm 2 when measured according to ASTM D-828, , An elongation in the MD direction of not less than 5.0%, and a tear strength in the MD direction of not less than 0.95 N measured according to TAPPI T414.
The flexible OLED device according to claim 2, wherein the meta-aramid paper has a tear strength in the MD direction of 20 Nm 2 / kg to 30 Nm 2 / kg when the thickness is 0.14 mm.
The flexible OLED device according to claim 1, wherein the meta-aramid paper has a basis weight of 35 g / m2 to 50 g / m2.
The method according to claim 1,
Wherein the meta-aramid paper comprises meta-aramid floc and meta-amide fibrids,
Wherein the flock and the fibrids have an intrinsic viscosity (IV) of 1.5 to 2.0.
The method of claim 1, wherein the planarization layer has a single-layer structure,
Polypropylene glycol dimethacrylate (PPGDMA), polypropylene glycol dimethacrylate (PPGDA), polypropylene glycol dimethacrylate (PEGDMA), polypropylene glycol dimethacrylate (PVP) glycol diacrylate, PDEGDA (poly diethylene glycol diacrylate), a POSS compound represented by the following formula (1), a silazane compound represented by the following formula (2), and a polysilazane compound. device;
[Chemical Formula 1]

In Formula 1, E is

,

or

And, R ^1, R ³ And Each of R ⁴ is independently an alkylene group having 2 to 5 carbon atoms, R ² is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, X is -NHR ⁵ , R ⁵ is a hydrogen atom, Lt; / RTI >
(2)

In Formula 2, R < ^{1 >} To R ⁹ Each independently represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, B is -NHR ¹⁰ , and R ¹⁰ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.
The method of claim 1, wherein the planarization layer is a multi-layer structure,
Polypropylene glycol dimethacrylate (PPGDMA), polypropylene glycol dimethacrylate (PPGDA), polypropylene glycol dimethacrylate (PEGDMA), polypropylene glycol dimethacrylate (PVP) glycol diacrylate, PDEGDA (poly diethylene glycol diacrylate), a POSS compound represented by the following formula (1), a silazane compound represented by the following formula (2), and a polysilazane compound;
And a second planarization layer comprising a polymer represented by the following formula (3)
A flexible substrate, a substrate layer, a first planarizing layer and a second planarizing layer are stacked in this order;
(3)

In the general formula (3), R &^lt; ¹ > Each R ⁸ is independently a hydrogen atom, a halogen atom, a carboxyl group, an amide group, -CF ₃ , -Si (OR) _m H _3-m , a formyl group or N is an rational number satisfying a weight average molecular weight of 50,000 to 200,000, and m is an integer of 0 to 3.
8. The composition of claim 7, wherein the polysilazane-
A polymer of a monomer represented by the following formula 4-1;
A copolymer comprising a compound represented by the following formula (4-1) and a compound represented by the following formula (4-2); And
A flexible OLED device comprising: a polymer represented by the following formula (4-3);
[Formula 4-1]

In Formula 4-1, R ¹ and R ² are each independently a hydrogen atom or an alkyl group having 1 to 3 carbon atoms,
[Formula 4-2]

In Formula 4-2, R ¹ is an alkyl group having 1 to 3 carbon atoms,
[Formula 4-3]

In Formula 4-3, R ¹ is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, R ² is an alkylene group having 2 to 5 carbon atoms, R ³ and R ⁴ are independently a hydrogen atom, An alkyl group having 1 to 3 carbon atoms or an alkoxy group having 1 to 3 carbon atoms, and R ⁵ is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.
The flexible OLED device according to claim 8, wherein the copolymer is obtained by copolymerizing the monomer represented by the formula (4-1) and the monomer represented by the formula (4-2) at a molar ratio of 1: 2 to 6:
8. The method of claim 7, wherein the first planarization layer
A dimethacrylate-based compound containing at least one selected from PEGDMA and PPGDMA; And
And a mixture containing the POSS compound, the silazane, and the polysilazane at a weight ratio of 1: 0.1 to 1.5.
The flexible OLED element according to claim 1, wherein the substrate layer, the planarization layer, the anode layer, the hole injecting-transporting layer, the light emitting layer, the electron transporting layer, the electron injecting layer and the cathode layer are sequentially stacked.
12. The flexible OLED device according to claim 11, further comprising a capping layer between the anode layer and the hole injecting and transporting layer, and further comprising a capping layer on an upper surface of the cathode layer.
12. The flexible OLED device according to claim 11, wherein the hole injection-transport layer comprises molybdenum oxide (MoO ₃ ) and TAPC (Di- [N- (N-ditolyl-amino) -phenyl] cyclohexane) .
12. The organic electroluminescent device of claim 11, wherein the light emitting layer comprises a host and a dopant,
The host includes a CBP (4,4'-Bis (N -carbazolyl ) -1,1'-biphenyl), the dopant is _{Ir (ppy) 3) (Tris} [2-? Phenylpyridinato-C 2, N] iridium < RTI ID = 0.0 > (III). < / RTI >
12. The method of claim 11, wherein the electron transport layer TPBi (N, N '-Di ( 1-naphthyl) - N, N' -diphenyl- (1,1'-biphenyl) -4,4'-diamine) , including Wherein the flexible OLED device is a flexible OLED device.
13. The flexible OLED device of claim 12, wherein the capping layer comprises TAPC (Di- [4- (N, N-ditolyl-amino) -phenyl] cyclohexane.
The flexible OLED device according to claim 6, wherein the first planarizing layer and the second planarizing layer have a thickness ratio of 1: 0.1 to 10.
2. The flexible OLED device according to claim 1, wherein the substrate layer has an average thickness of 0.1 to 150 mu m, and the planarizing layer has an average thickness of 0.1 to 10 mu m.
The flexible OLED device according to claim 1, wherein the planarization layer has a root mean square surface roughness (RMS) of 0.1 nm to 300 nm.
19. A device according to any one of claims 1 to 19, characterized in that when the voltage is between 3.0V and 6.0V and the current density is between 0.1 and 0.2 mA / cm < 2 >, the luminance is between 50 and 100 cd / And a second electrode.
The flexible OLED device according to any one of claims 1 to 19, characterized in that the external quantum efficiency (EQE) is 3 to 20% when the current density is 0.1 to 0.2 mA / .
The flexible OLED device according to any one of claims 1 to 19, wherein the PL wavelength intensity is 4 to 95 (arb. Unit) when the electroluminescence spectrum is measured.
PVP, PGMEA, PEGDMA, PPGDMA, PPGDA, PDEGDA, POSS system represented by the following formula (1), or a mixture thereof, on one side of the substrate of an aramid paper material containing at least one selected from the group consisting of meta-aramid paper, para- aramid paper and meta-para- Coating and drying a first planarization resin comprising at least one compound selected from the group consisting of silazanes and polysilazanes represented by the following general formula (2) to form a planarization layer;
Depositing a positive electrode layer, a positive electrode layer, a positive hole injection-transport layer, a light emitting layer, an electron transport layer, an electron injection layer and a negative electrode layer on the top surface of the planarization layer in sequence;
[Chemical Formula 1]

In Formula 1, E is

,

or

And, R ^1, R ³ And Each of R ⁴ is independently an alkylene group having 2 to 5 carbon atoms, R ² is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, X is -NHR ⁵ , R ⁵ is a hydrogen atom, Lt; / RTI >
(2)

In Formula 2, R < ^{1 >} To R ⁹ Each independently represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, B is -NHR ¹⁰ , and R ¹⁰ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.
24. The method of claim 23, wherein forming the planarization layer further comprises:
(1) comprising at least one selected from the group consisting of PMF, PVP, PGMEA, PEGDMA, PPGDMA, PPGDA, PDEGDA, POSS compounds represented by the following formula (1), silazane represented by the following formula Coating and drying the planarization resin to form a planarization layer; And
And forming a second planarization layer by coating and drying a second planarization resin including a polymer represented by the following Formula 3 on the upper surface of the first planarization layer. :
(3)

In the general formula (3), R &^lt; ¹ > Each R ⁸ is independently a hydrogen atom, a halogen atom, a carboxyl group, an amide group, -CF ₃ , -Si (OR) _m H _3-m , a formyl group or N is an rational number satisfying a weight average molecular weight of 50,000 to 200,000, and m is an integer of 0 to 3.
24. The method of claim 23, wherein the aramid paper is produced by performing a process that does not include a calendaring process,
A step of preparing a wet-web by inputting a material containing meta-aramid floc and meta-amide fibrids;
A second step of dewatering the wet paper;
A third step of drying the dehydrated wet paper by a first hot air blow;
A fourth step of drying the dried wet paper by secondary drying to produce paper; And
And drying the dried paper at a temperature of 250 ° C to 320 ° C.
26. The method of claim 25, wherein the primary hot air drying is hot air drying at a temperature of 195 deg. C to 250 deg.
The method of claim 25, wherein the second drying is performed at 100 ° C to 150 ° C, and the third drying is performed for 10 seconds to 80 seconds.
26. The method of claim 25,
Further comprising the step of compressing and dewatering the wet paper between the steps 2 and 3 or between the steps 3 and 4. The method of claim 1,

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