KR102049972B1 - Coating composite and display device comprising the same - Google Patents

Abstract

The coating composition according to an embodiment of the present invention includes a block copolymer in which a first block and a second block are polymerized, and the first block includes a hydrophobic group including any one selected from a fluoro group, an alkyl group, and a cycloalkyl group. And the second block includes a functional group for curing including any one selected from epoxy, acrylic or silicone.

Description

COATING COMPOSITE AND DISPLAY DEVICE COMPRISING THE SAME}

The present invention relates to a coating composition and a display device including the same, and more particularly, to a coating composition having excellent waterproofness and adhesion and a display device including the same.

Recently, with the development of various portable electronic devices such as mobile phones, PDAs, and notebook computers, the demand for light and thin flat panel display devices can be gradually increased. Liquid crystal display (LCD), plasma display panel (PDP), organic light emitting diode (OLED), etc. are being actively researched as such flat panel display devices. BACKGROUND ART Liquid crystal display devices, which are easy to drive and easily implement high image quality, have been in the spotlight.

The liquid crystal display includes a TFT array substrate having a thin film transistor (TFT) array as a switching element, and a color filter substrate having a color filter for converting a light source of a backlight into colors of R, G, and B. It includes a liquid crystal panel is bonded to each other. In order to drive the liquid crystal panel, electrical signals such as driving of a printed circuit board, a power signal, and the like are applied to a pad part provided on one side of the liquid crystal panel.

The liquid crystal display device is composed of high-precision electrical elements such as the above-described thin film transistor, but when the external moisture penetrates, there is a problem that the electrical characteristics of the electrical elements are lowered and the lifespan is shortened.

In particular, the liquid crystal display device is formed by applying a sealant such as a sealant along the edges of the TFT array substrate and the color filter substrate to bond the TFT array substrate and the color filter substrate. However, such a liquid crystal display cannot prevent external moisture from penetrating the sealing material. In particular, in the pad portion exposed to the outside, moisture penetrates directly into the metal pad and is very vulnerable to oxidation of the metal.

Therefore, a desiccant such as tuffy is applied to a region where external moisture can penetrate the liquid crystal display. However, the conventional desiccant has a problem in that corrosion occurs at the electrode part of the pad part under a high temperature / high humidity condition of 85% and a temperature of 85 ° C. Accordingly, there is an increasing demand for a desiccant that can prevent moisture from penetrating the liquid crystal display device, and in particular, prevent corrosion of the pad portion.

The present invention provides a coating composition having excellent waterproofness and adhesion and a display device including the same.

In order to achieve the above object, the coating composition according to an embodiment of the present invention includes a block copolymer in which the first block and the second block are polymerized, and the first block is a fluoro group, an alkyl group, or a cycloalkyl group. And a hydrophobic group including any one selected, and the second block includes a functional group for curing including any one selected from epoxy, acrylic, and silicone.

The first block or the second block may be formed independently of any one selected from the group consisting of acrylic resin, epoxy resin, siloxane resin, imide resin, urethane resin, ester, styrene resin and vinyl resin. have.

The block copolymer is included in an amount of 50 to 80 parts by weight based on 100 parts by weight of the coating composition.

The coating composition further includes an additive for increasing surface hydrophobicity, an adhesion promoter for increasing adhesion, and a polymerization initiator.

The additive includes a fluorine-based silane, the adhesion promoter includes a silane-based, zirconium-based, titanium-based or phosphorus-based coupling agent, the polymerization initiator includes a cationic initiator, a radical initiator or a photoinitiator.

The coating composition further includes a plurality of nanoparticles.

In addition, the display device according to an embodiment of the present invention includes a pad unit, a liquid crystal panel in which a TFT array substrate and a color filter substrate are bonded to each other, and a coating layer formed on at least one side of the liquid crystal panel and the pad unit, The coating layer is made of a coating composition, wherein the coating composition comprises a block copolymer in which a first block and a second block are polymerized, and the first block includes any one selected from a fluoro group, an alkyl group, or a cycloalkyl group. It includes a hydrophobic group, the second block includes a functional group for curing comprising any one selected from epoxy, acrylic or silicone.

The coating layer includes a plurality of nanoparticles.

Nanostructures are formed on the surface of the coating layer.

The coating composition prepared according to the embodiment of the present invention includes a block copolymer including a hydrophobic group and a curable functional group, thereby improving adhesion and improving waterproofness.

1 is a plan view illustrating a display device according to an exemplary embodiment of the present invention.
2 is a cross-sectional view taken along line II ′ of FIG. 1;
3 is an enlarged view illustrating an area A of FIG. 2 enlarged.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

An embodiment of the present invention relates to a coating composition for manufacturing a display device, and discloses manufacturing a coating composition using a block copolymer (BCP) in which different polymers are combined. Block copolymer refers to a material in which two or more chemically different polymers are bonded, that is, a unique type of polymer in which two or more different polymer chains are forcibly connected through chemical bonds.

Block copolymers have very long molecular rings, so their chemical and physical properties are unique compared to a single polymer or a single polymer, and because of their unique form of chemical bonding, they have uniform sizes and arrangements on the order of several tens of nanometers (nm). Self assembled structures in the form of spheres, cylinders, pillars, or lamellars may be formed.

The block copolymer constituting the coating composition of the present invention is copolymerized with the polymer of the first block having a hydrophobic group and the second block having a curable functional group for improving adhesion. Each of the first block and the second block is independently one selected from the group consisting of an acrylic resin, an epoxy resin, a siloxane resin, an imide resin, a urethane resin, an ester resin, a styrene resin, and a vinyl resin.

The first block includes a hydrophobic group including any one selected from a fluoro group, an alkyl group, and a cyclo alkyl group. Hydrophobic groups bonded to the first block impart hydrophobic properties to the surface of the coating composition to prevent penetration of moisture. The second block includes a functional group for curing including any one selected from epoxy, acrylic or silicone. The functional groups bonded to the second block serve to improve adhesion between the coating material and the coating composition and to cure the coating composition.

When the block copolymer of the present application is described as an example of copolymerization using siloxanes as the first block and the second block, for example, it may be represented by the following Chemical Formula 1.

[Formula 1]

In this case, the first block may be any one selected from a fluoro group, an alkyl group, or a cycloalkyl group is bonded to any one or more of R ₁ and R ₂ , the second block is an epoxy group, acrylic group to any one or more of R 3 and R 4 Or any one selected from silicon may be combined. In this case, m and n may be 1 to 10.

Such a block copolymer is prepared by polymerizing a first block and a second block. Here, the first block and the second block may be polymerized at a ratio of about 1: 1. In this case, when the content of the first block is large and the content of the second block is small, hydrophobicity may be improved, but adhesive strength may be lowered. In addition, when the content of the first block is small and the content of the second block is large, the adhesion may be improved but the hydrophobicity may be reduced. Therefore, the content of the first block and the second block needs to be properly adjusted to suit the purpose within the above range. The first block and the second block are polymerized through anionic polymerization or ring-opening polymerization.

The coating composition further includes an additive for increasing surface hydrophobicity, an adhesion promoter for increasing adhesion, and a polymerization initiator. The additive may be a fluorine-based silane, the adhesion promoter may be a silane, zirconium, titanium or phosphorus coupling agent, the polymerization initiator may be a cationic initiator, a radical initiator or a photoinitiator.

The coating composition further comprises a solvent, the solvent is methyl ethyl ketone, cyclohexanone, methyl isobutyl ketone, methyl cellosolve, ethyl cellosolve, tetrahydrofuran, dimethyl ether, propylene glycol dimethyl ether, propylene glycol di Any one selected from the group consisting of ethyl ether, propylene glycol ethyl methyl acetate, chloroform, methyl ether acetate, ethyl-3-ethoxypropionate, ethyl cellosolve acetate, and butyl acetate can be used.

The coating composition described above is prepared by mixing a block copolymer, an additive, an adhesion promoter and a polymerization initiator in a solvent. In this case, the block copolymer is included in 50 to 80 parts by weight based on 100 parts by weight of the total coating composition. Here, if the content of the block copolymer is 50 parts by weight or more based on 100 parts by weight of the total coating composition, it is possible to improve the hydrophobicity and adhesion of the coating composition, the content of the block copolymer is 80 parts by weight based on 100 parts by weight of the total coating composition If it is less than or equal, there is an advantage that the viscosity is high and the coating can be prevented from becoming difficult.

Meanwhile, the coating composition of the present invention may further include nanoparticles. The nanoparticles are intended to form a nanostructure in which the surface of the coating layer is uneven when the coating composition is later applied to form the coating layer. The reason for forming the nanostructure on the coating layer is to show the super water-repellent phenomenon seen in the lotus leaf pattern. The super water-repellent phenomenon seen in the lotus leaf pattern is related to the large and small protrusions present on the surface of the lotus leaf. The protrusion shape minimizes the contact surface area of the water droplets on the lotus leaf, causing the water droplets to form or roll down on the lotus leaf.

Porous silica nanoparticles may be used as the nanoparticles, and may be mixed with the coating composition in an amount of 1 to 20 parts by weight. When the coating composition is applied, nano-sized nanostructures are formed on the surface of the coating layer due to the nanoparticles.

Hereinafter, a display device using the coating composition according to an embodiment of the present invention described above will be described. 1 is a plan view illustrating a display device according to an exemplary embodiment of the present invention, FIG. 2 is a cross-sectional view taken along line II ′ of FIG. 1, and FIG. 3 is an enlarged view of region A of FIG. 2 enlarged. As an example of the display device, a liquid crystal display device will be described.

1 and 2, the liquid crystal display device 100 according to an exemplary embodiment of the present invention includes a liquid crystal panel 110 and a chip on film (COF) 150 connected to the liquid crystal panel 110. In more detail, the liquid crystal panel 110 includes a thin film transistor (TFT) array substrate 120 and a color filter substrate 130. Although not shown, a liquid crystal layer is formed between the TFT array substrate 120 and the color filter substrate 130.

The TFT array substrate 120 is formed such that data lines and gate lines (or scan lines) intersect each other on a lower glass substrate, and liquid crystal cells are formed in cell regions defined by the data lines and gate lines. Arranged in matrix form. The TFT formed at the intersection of the data lines and the gate lines transfers the data voltage supplied through the data lines to the pixel electrode of the liquid crystal cell in response to the scan pulse from the gate line. For this purpose, the gate electrode of the TFT is connected to the gate line, and the source electrode is connected to the data line. The drain electrode of the TFT is connected to the pixel electrode of the liquid crystal cell. The common voltage is supplied to the common electrode facing the pixel electrode.

The color filter substrate 130 includes a black matrix and a color filter formed on the upper glass substrate. The common electrode is formed on the upper glass substrate in a vertical electric field driving method such as twisted nematic (TN) mode and vertical alignment (VA) mode, and a horizontal electric field such as IPS (In Plane Switching) mode and FFS (Fringe Field Switching) mode. The driving method is formed on the lower glass substrate together with the pixel electrode. A polarizing plate is attached to each of the upper glass substrate and the lower glass substrate, and an alignment layer for setting the pre-tilt angle of the liquid crystal is formed. A spacer is formed between the upper glass substrate and the lower glass substrate of the liquid crystal panel 110 to maintain a cell gap of the liquid crystal layer. The liquid crystal mode of the liquid crystal panel 110 may be implemented in any liquid crystal mode as well as the above-described TN mode, VA mode, IPS mode, FFS mode.

The liquid crystal panel 110 includes a pad unit 140 to be connected to the COF 150. The pad unit 140 is formed with a plurality of pad electrodes connected from gate lines and data lines formed on the TFT array substrate 130, and a driving signal is inputted from the driving ICs 155 formed in the COF 150. And are exposed for transmission to data lines. The other side of the COF 150 is a printed circuit board (PCB) 160 is connected. The pad unit 140 may be connected to one side of the COF 150 to transmit a driving signal to the TFT array substrate 130.

On the other hand, the liquid crystal display device 100 of the present invention includes a coating layer 170 formed on at least one side 115 and the pad portion 140 of the liquid crystal panel 110. In more detail, the coating layer 170 is formed on at least one side 115 of the liquid crystal panel 110, where the side 115 of the liquid crystal panel 110 includes a TFT array substrate 120 and a color filter substrate 130. The outer surface of the bonded interface. 1 and 2, the coating layer 170 is formed on all sides 115 of the liquid crystal panel 110. However, the present invention is not limited thereto and may be formed on at least one side.

In addition, the coating layer 170 is formed on the pad portion 140 of the liquid crystal panel 110. The pad part 140 is a place where pad electrodes (not shown) are exposed to the outside and connected to the COF 150, which is the most vulnerable to external moisture penetration. Therefore, in the present invention, the coating layer 170 is formed on the pad part 140. Here, the coating layer 170 may cover at least the pad portion 140, and may be additionally applied to a part of the COF 150 connected to the pad portion 140.

The coating layer 170 may be formed of the above-described coating composition, it is applied by the dispensing method. After coating, the final curing is performed using a method such as UV curing, thermal curing or room temperature curing.

Meanwhile, referring to FIG. 3, the display device according to the exemplary embodiment may further include nanoparticles 175 in the coating layer 170. As described above, the nanoparticle 175 is for forming the nanostructure 180 on the surface of the coating layer 170, the nanostructure 180 generates a super water-repellent phenomenon such as lotus leaf effect. The nanostructure 180 is formed of nano-sized protrusions due to the plurality of nanoparticles 175 included in the coating layer 170.

The nanostructure 180 may be formed in a random shape. Alternatively, the nanostructure 180 may be formed in a regular shape using a mold or the like. In addition, the nanostructure 180 may be formed of a separate material, for example, a resin, in addition to including nanoparticles.

As described above, the display device according to an embodiment of the present invention additionally forms the nanostructure 180 on the coating layer 170, so that when the water droplets contact the coating layer 170, due to the lotus leaf effect of the water droplets The contact angle θ becomes large, and there is an advantage that the water resistance can be improved.

Hereinafter, the coating composition of the present invention will be described in detail in the following experimental examples. However, the following experimental examples are merely to illustrate the present invention is not limited to the following experimental examples.

Experimental Example 1

A siloxane resin is used as the first block and the second block, respectively, and a fluoro group is bonded to the siloxane of the first block, an epoxy group is bonded to the siloxane of the second block, and the first block and the second block are then subjected to an anionic polymerization reaction. To prepare a block copolymer represented by the formula (2). 50 parts by weight of block copolymer, 5 parts by weight of fluorine-based silane as an additive, 5 parts by weight of silane coupling agent as adhesion promoter, and 5 parts by weight of benzoyl peroxide as radical initiator as polymerization initiator PGMEA (propylene glycol monomethyl ether acetate) 35 parts by weight of the coating composition was prepared.

[Formula 2]

Experimental Example 2

10 parts by weight of silica particles were mixed with the coating composition prepared according to Experimental Example 1, to prepare a coating composition.

Comparative example

A tuffy composition made of a conventional urethane acrylate was prepared.

After coating the composition prepared according to the above Experimental Example 1, 2 and Comparative Example to a thickness of 0.3mm on a glass substrate to form a coating layer, by dropping the water droplets to measure the contact angle is shown in Table 1 below. Here, in the case of Experiment 1, the contact angle was measured three times for each region.

# Contact angle (°)
Experimental Example 1
One 90.2 2 87.0 3 94.8 Experimental Example 2 One 160.5 Comparative example One 65.5

Referring to Table 1, in the case of the comparative example of the conventional tuffy, the contact angle of the water droplets appeared about 65 degrees, it was confirmed that the coating layer prepared according to Experimental Example 1 of the present invention was increased to an average of about 90 degrees three times. Moreover, it was confirmed that the coating layer of Experimental Example 2, which further includes nanoparticles in the coating composition of Experimental Example 1, had a contact angle of about 160 degrees.

That is, the coating composition prepared according to an embodiment of the present invention includes a block copolymer including a hydrophobic group and a curable functional group, thereby improving adhesion and improving waterproofness.

Although the embodiments of the present invention have been described above with reference to the accompanying drawings, the technical configuration of the present invention described above may be modified in other specific forms by those skilled in the art to which the present invention pertains without changing its technical spirit or essential features. It will be appreciated that it may be practiced. Therefore, the embodiments described above are to be understood as illustrative and not restrictive in all aspects. In addition, the scope of the present invention is shown by the claims below, rather than the above detailed description. Also, it is to be construed that all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts are included in the scope of the present invention.

100: display device 110: liquid crystal panel
120: TFT array substrate 130: color filter substrate
140: pad portion 150: COF
160: printed circuit board 170: coating layer

Claims (9)

A liquid crystal panel including a pad part and having a TFT array substrate and a color filter substrate bonded thereto; And
At least one side of the liquid crystal panel and a coating layer formed on the pad portion,
The coating layer is made of a coating composition, wherein the coating composition comprises a block copolymer in which the first block and the second block are polymerized,
The first block includes a hydrophobic group including a fluoro group, the second block includes a functional group for curing including an epoxy group,
The first block and the second block are each independently made of a siloxane resin,
The coating composition further includes a fluorine-based silane as an additive for increasing surface hydrophobicity, a silane coupling agent as an adhesion promoter for increasing adhesion, and a radical initiator as a polymerization initiator.
delete According to claim 1,
The block copolymer is 50 to 80 parts by weight based on 100 parts by weight of the coating composition.
delete delete According to claim 1,
The coating composition further comprises a plurality of nanoparticles.
delete delete According to claim 1,
A display device in which a nanostructure is formed on a surface of the coating layer.

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