KR101078059B1 - Flexible substrate - Google Patents

Abstract

The present invention relates to a flexible substrate, and more particularly, by curing the primer layer by EB, there is no environmental pollution because the solvent is not used, the curing time is not long, and the manufacturing time can be shortened. By incorporating into a phthalate resin, the present invention relates to a flexible substrate having excellent dimensional stability and low moisture permeability. To this end, the flexible substrate according to the present invention is coated on the biaxially stretched base film and 0.2 to 10wt% of nanodiamond powder in polyethylene naphthalate resin and the biaxially stretched base film, and cured by EB (E-Beam) irradiation. It is characterized in that it comprises an adhesive layer coated with a cationic polymerization-based adhesive is made and the inorganic barrier layer deposited on the adhesive layer.

Description

Flexible Substrate {FLEXIBLE SUBSTRATE}

The present invention relates to a flexible substrate, and more particularly, by curing the primer layer by EB, there is no environmental pollution because the solvent is not used, the curing time is not long, and the manufacturing time can be shortened. By incorporating into a phthalate resin, the present invention relates to a flexible substrate having excellent dimensional stability and low moisture permeability.

In general, flexible displays are lighter, thinner, and larger in size than conventional CRT displays, and thus commercialization is being accelerated. In addition, the flexible display is very advantageous in terms of cost reduction because it has a roll-to-roll process because of its inherent physical properties, and thus it is expected to be widely used for various purposes in the future. It is a material.

However, the substrate must be used by the user to withstand high temperatures in the process of forming transistors and requires dimensional stability before and after device formation, but polymer organic substrates have a temperature range of use, especially when exposed to high temperatures for extended periods of time due to polymer properties. The change is severe.

Accordingly, polyethylene naphthalate, which is relatively excellent in dimensional stability and capable of producing roll-to-roll, is used as a base film. At this time, by incorporating the nanodiamond powder into the polyethylene naphthalate resin, the coefficient of thermal expansion is further improved without impairing the transparency, and the barrier layer is deposited with the improvement of the dimensional stability to lower the moisture transmittance. In addition, a primer layer is coated to increase the adhesion between the base film and the barrier layer, and a conventional method uses a conventional solvent type thermosetting or UV curing adhesive (application number JP2005-041193, JP2004-058548).

However, in the present invention, after applying the primer layer (cationic polymerization-based adhesive), the primer layer is cured with EB immediately after barrier deposition. Energy cost of EB is lower than that of existing thermosetting and UV curing (application number JP2005-041193, JP2004-058548) (thermosetting: UV curing: EB curing = 40 ~ 200: 3 ~ 30: 1) , Manufacturing method and application development, TRC R & D Library, p.34

Japanese Patent Application No. 2005-041193 Japanese Patent Application No. 2004-058548

 Manufacturing Method and Application of Photocurable Material, TRC R & D Library, p34

The present invention has been made to solve the above problems, the object of the present invention is to reduce the environmental pollution, the curing time is not long because the solvent is not used, it is possible to shorten the manufacturing time, excellent dimensional stability and moisture permeability It is to provide a low flexible substrate.

These and other objects and advantages of the present invention will become more apparent from the following description of a preferred embodiment thereof.

The object is a biaxially stretched base film in which 0.2-10 wt% of nanodiamond powder is mixed with polyethylene naphthalate resin, and a cationic polymerization which is coated on the biaxially stretched base film and cured by EB (E-Beam) irradiation. It is achieved by a flexible substrate comprising an adhesive layer coated with a system adhesive and an inorganic barrier layer deposited on the adhesive layer.

Here, the curing by EB (E-Beam) irradiation of the adhesive layer is characterized in that it is made immediately after the deposition of the inorganic barrier layer.

Preferably, the size of the nano diamond powder is characterized in that 1 ~ 100nm.

Preferably, the inorganic barrier layer is a single material or at least one of Al, Si, Mg, Ti, Sn, In, Cr or Ni transparent inorganic oxide film, transparent inorganic oxide and nitride film, transparent inorganic nitride film or transparent metal film It is characterized by the mixture of the above.

Preferably, the flexible substrate has a coefficient of linear thermal expansion of 10 ppm / ° C. or less and a water transmittance of 0.1 g / m 2 · day or less.

Preferably, the biaxially stretched base film is characterized in that it further comprises an additive such as a dispersion enhancer for the dispersion of the nanodiamond powder.

Preferably, the flexible substrate is used as a flexible substrate for an E-paper, a flexible substrate for an OLED, or a flexible substrate for a solar cell.

According to the present invention, by curing the primer layer by EB, there is no environmental pollution because the solvent is not used, the curing time is not long, the production time can be shortened, and the dimensional stability is achieved by incorporating the nanodiamond powder into the polyethylene naphthalate resin. It has excellent effects and low moisture permeability.

Hereinafter, the present invention will be described in detail with reference to embodiments and drawings of the present invention. These examples are only presented by way of example only to more specifically describe the present invention, it will be apparent to those skilled in the art that the scope of the present invention is not limited by these examples. .

The flexible substrate according to the present invention is coated on the biaxially stretched base film and 0.2 to 10wt% of nanodiamond powder in polyethylene naphthalate resin, and coated on the biaxially stretched base film, the curing is made by EB (E-Beam) irradiation And an adhesive layer coated with a cationic polymerization adhesive, and a single unit or a multilayer unit repeating layer of an inorganic barrier layer deposited on the adhesive layer.

In addition, curing by the EB (E-Beam) irradiation of the adhesive layer is characterized in that it is made immediately after the deposition of the inorganic barrier layer.

The polyethylene naphthalate resin according to the present invention is 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid or 2,7-naphthalenedicarboxylic acid, preferably 2,6-naphthalenedicar It can be obtained by a process consisting of esterification or transesterification and polymerization reaction of condensing an acid, or a lower alkyl (6 or less carbon atoms) diester and ethylene glycol, and the base film by serial or simultaneous biaxial stretching. Get Here, when the resin is formed, in some cases, a solid phase polymerization step is performed to increase the IV (intrinsic viscosity). In addition, polyethylene naphthalate may copolymerize or blend at least one or more of terephthalic acid, phthalic acid, isophthalic acid, and / or their derivatives, that is, lower alkyl diester derivatives, for cost reduction. At this time, in the polymerization step, the nanodiamond powder is mixed with 0.2 to 10 wt% of dispersion based on the solid content of naphthalene dicarboxylic acid or a derivative thereof to polymerize. In some cases, it is also possible to make a masterbatch chip and mix the chip during the extrusion process of the film. In addition, the size of the nanodiamond powder is preferably 1 ~ 100nm. Nanodiamond powder has the effect of improving the dimensional stability of the substrate, while the diamond does not impair transparency at nano size. In this case, when the amount of the mixture is less than 0.2 wt%, the effect of dimensional stability is not observed. On the contrary, when the amount of the mixture is more than 10 wt%, the amount of the mixture is large, the rigidity is large and easily broken. In addition, when the size of the nanodiamond powder is less than 1 nm, the production of the nano diamond powder is difficult, and when the size of the nano diamond powder exceeds 100 nm, the permeability is lowered and the adhesion with the substrate is preferably in the above range. In some cases, when the nanodiamond powder dispersion is added, it is also possible to add an additive such as a dispersion enhancer to improve dispersion. In addition, in order to improve the adhesion with the substrate, the nanodiamond powder may be pretreated to coat the adhesion improving agent.

In the case of cationic polymerization-based adhesives cured in EB according to the present invention, cationic polymerization-based monomers and oligomers are themes, and specifically, epoxy-glycidyl ethers, alicyclic epoxys, oxetanes, and vinyl ethers. The system may be mixed or single selected. Cationic polymerization-based adhesives are particularly advantageous in that the thin film can be cured and the curing shrinkage is small. As a coating method, general wet coating is possible in a solventless type or a solvent type. It is preferable that the cationic polymerization-based adhesive is made of EB curing immediately after barrier layer deposition. During EB curing, E-Beam has a deeper depth of irradiation in the thickness direction than heat curing or UV curing, and thus the curing speed is high even after curing. This is because solvent resistance can be used. In addition, unlike UV curing, it has the advantage that no separate photopolymerization initiator is required. However, when hardening is complete according to an after cure operation, you may use a thermal polymerization initiator together. The electron beam acceleration voltage of EB irradiation is 30 kV-500 kV, and 50-300 kV is preferable. In the case where the electron beam acceleration voltage is less than 30 kV, there is a fear that the transmission shortage of the electron beam may occur when the thickness of the composition is thick.

In the barrier layer according to the present invention, at least one of one of Al, Si, Mg, Ti, Sn, In, Cr, Ni, a transparent inorganic oxide film, a transparent inorganic nitride film, a transparent inorganic oxide / nitride film, and a transparent metal film It is formed by depositing in a mixture of the above. Particularly preferably, it is selected from one or more of an oxide film of aluminum, silicon, a nitride film, or an acid-nitride film. Suitable formation methods here include deposition by chemical vapor deposition (CVD), plasma enhanced chemical vapor deposition (PECVD), atmospheric pressure chemical vapor deposition (APCVD), physical vapor deposition (PVD), and sputtering deposition.

As described above, the flexible substrate formed according to the embodiment of the present invention is characterized in that its linear thermal expansion coefficient (KS M3060) is 10 ppm / ° C. or lower at a temperature of -30 ° C. to 30 ° C., and a moisture transmittance (JIS K 7126B). It is 0.1 g / m <2> * day or less.

Hereinafter, the configuration and effects of the present invention will be described in more detail through examples, comparative examples, and polymer property analysis experiments.

Example 1

Into dimethyl-2,6-naphthalene dicarboxylate and ethylene glycol, 0.05 wt% manganese acetate tetrahydrate based on the transesterification catalyst solids and 0.05 wt% GeO ₂ on the solids basis were added as polymerization catalysts, and the average particle size was 50 nm. After adding 2wt% of the nanodiamond powder based on solids, the transesterification reaction was completed, and about 0.05wt% of the phosphorus-based heat stabilizer was added to the solids based on the solids before the polymerization reaction to obtain a polymerization chip. Next, the sheet produced by extruding the polymerized chip using a twin screw extruder was biaxially stretched to obtain a substrate film having a thickness of 100 μm.

Polyethylene naphthalate by bar coating a mixture of oxetane-based monomer (TOGOSEI, OXT-101, 20wt%) with a general epoxy-based monomer (UCC UVR-6110) as an EB (E-Beam) curable adhesive on the base film (PEN) After coating on the base film and dried at room temperature.

Next, the barrier layer was raised to a thickness of 100 nm by sputtering using a Si target, and then cured by being exposed to an EB device with an acceleration voltage of 150 kV for 0.5 second.

The coefficient of linear thermal expansion of the thus prepared flexible substrate was 9 ppm / 占 폚, and the water transmittance was 0.073 g / m 2 · day. Also, when the presence of a warrior, nothing was transferred.

[Example 2]

A flexible substrate was prepared in the same manner as in Example 1 except that 5 wt% of the nanodiamond powder was used.

The coefficient of linear thermal expansion of the thus prepared flexible substrate was 7 ppm / 占 폚, and the water transmittance was 0.072 g / m 2 · day. When the presence of a warrior, nothing was transferred.

Example 3

A flexible substrate was manufactured in the same manner as in Example 1, except that the barrier layer was raised with a thickness of about 100 nm of aluminum oxide by a sputtering method.

The linear thermal expansion coefficient of the thus produced flexible substrate was 8 ppm / 占 폚, and the water transmittance was 0.080 g / m 2 · day. When the presence of a warrior, nothing was transferred.

Example 4

On the PEN substrate film prepared in Example 1, a flexible substrate was manufactured in the same manner as in Example 1 except that the unit was formed three times to form an adhesive layer and a barrier layer.

The linear thermal expansion coefficient of the thus produced flexible substrate was 5 ppm / 占 폚, and the water transmittance was 0.007 g / m 2 · day. When the presence of a warrior, nothing was transferred.

Comparative Example 1

A flexible substrate was manufactured in the same manner as in Example 1, except that nano diamond powder was not mixed in the preparation of the PEN film.

The linear thermal expansion coefficient of the thus produced flexible substrate was 13 ppm / 占 폚, and the water transmittance was 0.091 g / m 2 · day. When the presence of a warrior, nothing was transferred.

Comparative Example 2

Use 5 wt% of the curing agent in difunctional epoxy resin (diglycidyl ether of bisphenol A, DGEBA) as an adhesive, and do not use EB curing when drying the adhesive layer after adhesive coating and barrier deposition. A flexible substrate was prepared in the same manner as in Example 1, except that 5 seconds was dried at 1500 rpm and 175 ° C. for 5 seconds.

The flexible substrate thus produced had a silicon oxide layer deposited on the front of the tape when the transfer was confirmed.

Comparative Example 3

In the same manner as in Example 1, only the PEN base film was made, and the adhesive layer and the barrier layer were not raised.

The coefficient of linear thermal expansion of the thus produced flexible substrate was 15 ppm / 占 폚, and the water transmittance was 1.5 g / m 2 · day.

The numerical value measured in the said Example and the comparative example used the following measuring method.

[How to measure]

1. The coefficient of linear expansion coefficient is measured according to KS M3060.

2. Moisture permeability is based on the method specified by JIS K 7126B using MOCON equipment.

3. To determine the degree of adhesion of the coating layer, attach the Nitto 31B tape, rub 3 times in the same direction with a 3 kg roll, and then remove the Nitto 31B tape again and visually check that the barrier layer has been transferred to the tape adhesive side.

division Example
One Example
2 Example
3 Example
4 Comparative example
One Comparative example
2 Comparative example
3 Nano diamond mixing O O O O X O O Nano Diamond Content (wt%) 2 5 2 2 - 2 2 Adhesive coating method EB hardening EB hardening EB hardening EB hardening EB hardening Thermosetting - Barrier layer
material Oxidation
silicon Oxidation
silicon Aluminum oxide Oxidation
silicon Oxidation
silicon Oxidation
silicon - Coefficient of thermal expansion
(ppm / ℃) 9 7 8 5 13 - 15 Moisture permeability
(g / ㎡day) 0.073 0.072 0.080 0.007 0.091 - 1.5 Transcription X X X X X O -

In Example 1, Example 2, and Comparative Example 1 in Table 1, it can be seen that the coefficient of linear thermal expansion decreases as the content of the nanodiamond powder increases, and in the case of Example 1 and Comparative Example 3, the barrier layer It can be seen that the moisture permeability is remarkably decreased by applying. In addition, in Example 1 and Comparative Example 2, in the case of thermal curing, even if the heat exposure time is 15 seconds (LTE-S manufactured by MATHIS (SWITZERLAND), 150 ℃, 1500rpm), it can be seen that the transfer is easily transferred during the evaluation of the presence of transcription In the case of EB hardening, it can be seen that the adhesive was cured only by exposure of 0.5 seconds.

The flexible substrate according to the present invention may be used as a flexible substrate for E-paper, a flexible substrate for OLED, or a flexible substrate for solar cell having a low moisture permeability.

Claims (7)

In the flexible substrate,
Biaxially stretched base film which mixed 0.2-10 wt% of nanodiamond powder in polyethylene naphthalate resin,
An adhesive layer coated on the biaxially stretched base film and coated with a cationic polymerization-based adhesive that is cured by EB (E-Beam) irradiation;
A flexible substrate, characterized in that it comprises an inorganic barrier layer deposited on the adhesive layer. The method of claim 1,
The hardening by EB (E-Beam) irradiation of the said adhesive bond layer is carried out immediately after the deposition of the said inorganic barrier layer, The flexible board | substrate. The method of claim 1,
The nano-diamond powder has a size of 1 to 100 nm, the flexible substrate. The method of claim 1,
The inorganic barrier layer is a single material or a mixture of at least one of Al, Si, Mg, Ti, Sn, In, Cr, or Ni transparent inorganic oxide film, transparent inorganic oxide / nitride film, transparent inorganic nitride film, or transparent metal film. A flexible substrate, characterized in that. delete The method of claim 1,
The biaxially stretched base film further comprises an additive such as a dispersion enhancer for the dispersion of the nanodiamond powder, the flexible substrate. The method according to any one of claims 1 to 4,
The flexible substrate is a flexible substrate, characterized in that used as a flexible substrate for E-paper, a flexible substrate for OLED or a flexible substrate for solar cells.