WO2014196733A1

WO2014196733A1 - Method of manufacturing carbon nanotube polarizing film and carbon nanotube polarizing film thereby

Info

Publication number: WO2014196733A1
Application number: PCT/KR2014/003353
Authority: WO
Inventors: 이승희; 임영진; 박혜령
Original assignee: 전북대학교 산학협력단
Priority date: 2013-06-04
Filing date: 2014-04-17
Publication date: 2014-12-11
Also published as: KR102028209B1; KR20140142453A

Abstract

The present invention relates to manufacturing a polarizing film. More particularly, the present invention relates to a method of manufacturing a polarizing film by making a carbon nanotube cluster as a film through a simple process, the method comprising the steps of: mixing and applying a carbon nanotube cluster and a polymeric material on a substrate; providing an electric field or a magnetic field to the substrate, on which the mixture is applied, to elongate the carbon nanotube cluster in a certain direction; and providing heat or light to cure the polymeric material.

Description

【Specification】

[Name of invention]

Manufacturing method of carbon nanotube polarizing film and carbon nanotube polarizing film thereby

The present invention relates to a method for producing a carbon nanotube polarizing film, applying an electric or magnetic field to a composition in which a carbon nanotube cluster and a polymerizable material are mixed, and carbon nanotube polarization film-forming a stretched and aligned carbon nanotube cluster It relates to a method for producing a film.

Background Art

Recently, LCD displays, which have the upper hand in flat panel displays, are being threatened in the display market due to the rapid growth of organic light emitting displays. Accordingly, the required image quality characteristics are also increasing, and researches for improving the characteristics of conventional liquid crystal modes, backlights, and polarizers have been conducted for the sake of this need. The polarizing film is a mechanism having a function of transmitting and shielding light, and in the LCD, the polarizing film is a basic component because it functions to switch light. In addition to the LCD, the polarizing film is applied to small devices such as electronic calculators and wristwatches in the early stages of development, and recently, laptop personal computers, word processes, liquid crystal color projectors, car navigation systems, liquid crystal televisions, personal phones, and indoors. It is extensive in other measuring instruments.

Conventional polarizing film is made of a polyvinyl alcohol (PVA) film polarizer is dyed with iodine or dichroic dye and is prepared in a structure including a protective film on one or both sides.

However, since the polarizer uses a method of attaching a product in the form of a film to the outside of the liquid crystal device, it is difficult to control the process and causes a defect, thereby lowering the production yield and inevitably increasing the cost. In addition, the conventional attachment type polarizing plate has a disadvantage in that the intensity of the polarized light is fixed by stretching the film.

Korean Patent Laid-Open Publication No. 2006-0092737 relates to a film composed of carbon nanotubes and a method of manufacturing the same, and provides a carbon nanotube film having optical transparency in the visible light region. A carbon nanotube bundle is deposited on a substrate using a Tangmuir-Blodgett method to disclose a uniform or patterned carbon nanotube film and a method of manufacturing the same. The patent document describes that carbon nanotubes prepared by the above method are extremely thin and uniform enough to have conductivity and transparent, and can be used in electronic devices, sensors, displays, etc. because the carbon nanotubes are oriented in one direction at a high density. It is done. However, the above technology has no choice but to manufacture on a small scale in very limited places. However, not only commercial production is possible, but also the durability of the film is weak, and it is difficult to secure reliability as a material.

On the other hand, the present invention is the first in the world to announce the property that the cluster of carbon nanotubes is stretched (expanded) more than four times when the electric field is applied to the carbon nanotubes dispersed in the liquid crystal in the form of a cluster, and restored for the first time when the electric field is turned off. Nano Letters August issue).

The present invention intends to utilize the electrical properties of the newly identified carbon nanotubes in the production of polarizing film.

[Detailed Description of the Invention]

[Technical problem]

It is an object of the present invention to provide a method for producing a polarizing film having a polymerizable composition layer in which carbon or notube clusters are aligned and elongated only by a simplified process using an electric or magnetic field.

Technical Solution

In order to achieve the above object, the present invention

Mixing and applying carbon nanotube clusters and polymerizable materials onto a substrate; Stretching the carbon nanotube clusters in a predetermined direction by providing an electric or magnetic field to the substrate coated with the mixture; and

It relates to a method for producing a carbon nano-leuze polarizing film comprising the step of providing heat or light to cure the polymerizable material.

In another aspect, the present invention is a carbon nanotube polarizing film prepared by the above method, wherein the polarizing film is carbon nanotubes including a carbon nanotube crust fixed to the binder is stretched in one direction with a binder cured polymerizable material Relates to tube polarizing film.

In another aspect, the present invention relates to a liquid crystal display device in which the carbon nanotube polarizing film is coated on or inside the liquid crystal display device.

Advantageous Effects

The present invention can solve problems such as occurrence of defects due to dust or the like caused by mounting a polarizing plate of a film type using a conventional adhesive because it is mounted on the inside or outside of the liquid crystal display.

In addition, the present invention, unlike the conventional stretch type polarizing plate can control the polarization of light by using an electric or magnetic field can realize a very fast process speed, it is possible to build a more simplified process line and thus the cost is reduced have. In addition, since the polarizing material of the present invention is an inorganic material, compared with the conventional polarizing plate, the temperature limitability is improved to 150 ^° C. or more, thereby providing a polarizing plate capable of expanding the operating temperature range of the display.

The polarizing film manufacturing method of the present invention may change the transmittance or intensity of the polarized light by adjusting the length (width) of the carbon nano-lube cluster with the intensity of the electric field.

Therefore, widespread commercialization is expected in the future. ^'

[Brief Description of Drawings]

FIG. 1 is a schematic diagram of a device for forming a polarizing film using a polymerizable liquid crystal composition in which carbon nanotube clusters aligned and elongated by an electric field are mixed according to a first embodiment of the present invention.

2 shows a schematic view of an electric field generating device according to a first embodiment of the present invention when the substrate is in the form of a sheet.

FIG. 3 illustrates an electric field distribution diagram generated when voltage is alternately applied in the electric field generator of FIG. 2.

Figure 4 shows a schematic diagram of a polarizing film manufacturing process when the substrate is in the form of a sheet (sheet).

5 shows a schematic view of the completed polarizing film.

<25>

[Form for implementation of invention]

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In general, the nomenclature used herein and the experimental methods described below are well known and commonly used in the art.

In accordance with one aspect of the present invention, a method of manufacturing a carbon nanotube polarizing film of the present invention includes the steps of: mixing and applying a carbon nanotube cluster and a polymerizable material on a substrate; Stretching the carbon nanotube clusters in a predetermined direction by providing an electric or magnetic field to the substrate coated with the mixture; And providing heat or light to cure the polymerizable material.

In the present invention, first, a carbon nanotube cluster and a polymerizable material are mixed and applied onto a substrate.

The polymerizable material may be a polymer that is cured by heat or ultraviolet rays or a monomer thereof. More specifically, the polymerizable substance is tri acetyl cellulose (Tri acetyl). cellulose; TAC), Polyacryl Group, Polyolefin (Po), Polycarbonate (PC), Polyethylene Telephthalate (PET), Polypropylene (PP), Polyethylene (PE) ) And monomers thereof.

In the present invention, the polymerizable material may be a polymerizable liquid crystal material. The polymerizable liquid crystal material is a liquid crystalline monomer having a polymerizable group by irradiation with light such as heat or ultraviolet rays. Unlike the liquid crystal whose phase changes with temperature, the polymerizable liquid crystal material is solid phase. When the phase change no longer occurs, it refers to a material mainly used for optical films. For example, the liquid crystalline monomer having a polymerizable group exhibits a liquid crystal phase including a mesogen group capable of exhibiting liquid crystallinity and a terminal group capable of photopolymerization, and a monomer molecule capable of photopolymerization by a photoinitiator reacting to ultraviolet rays. Can be. As mesogen, a calamitic mesogen expressing a nematic liquid crystal phase or a discotic mesogen in a dish form capable of expressing a discotic liquid crystal phase may be used. As the polymerizable end group, an acryl group, a methacryl group, a vinyl ether group or an epoxide group, which are generally easy to be radically polymerized, may be used. The liquid crystalline monomer may be used in combination with a polymerizable mesogen compound having two or more polymerizable functional groups, for example, a general male to semi-male compound and / or a non-polar to polar compound to increase crosslinking of the polymer. The alignment profile can be changed by changing their composition ratio.

<3i> Examples of the liquid crystalline monomers include RM257, EHA, and RMS-013C.

Trimethylopropane triacrylate may be used as the photoinitiator.

The mixture represents a composition in which carbon nanotubes are mixed with the polymerizable material or the polymerizable liquid crystal material as the polymerizable composition. For example, the polymerizable composition may include carbon nanotubes and a solvent in the polymerizable material. In addition, the polymerizable composition may include carbon nanotubes and a solvent in the polymerizable liquid crystal material. The solvent is removed during the curing process.

<34> Carbon nanotubes that can be used in the present invention is a single-walled carbon nanotubes

SWCNTC Single-Walled Carbon Nano Tube (DWCNT), Double-Walled Carbon Nano Tube (DWCNT), Thin Multi-walled Carbon Nano Tube (tD) Thin Multi Walled Carbon Nano Tube (CNT) and Multi-walled Carbon Nanotube 丽 CNT (Multi) Walled Carbon Nano Tube) can be used.

<35> Carbon nanotubes have good elasticity and have good bending characteristics, but the carbon nanotubes have a small extension of about 10% depending on voltage. However, carbon nanotubes are clogged in the polymerizable liquid crystal composition. When present in a ster form, the carbon nanotube cluster may be stretched more than four times with an electroactive constant of 70 (V / um) or more.

In the present invention, it is intended to apply to the polarizing film by using the electrical properties of the carbon nanotube cluster.

The carbon nanotube cluster may be formed by dispersing the carbon nanotube in the polymerizable (liquid crystal) composition. When a small amount of carbon nanotubes are dispersed in the polymerizable composition, a polymerizable (liquid crystal) composition, for example, a liquid crystal molecule, is fixed on the surface of the carbon nanotubes by electrostatic attraction and thus the interaction between the carbon nanotubes (electrostatic Attraction), but as the content of carbon nanotubes increases, the interaction between them increases, making dispersion difficult, and further, coarsening occurs between the carbon nanotubes.

As used herein, the term “carbon nanotube cluster” refers to an aggregate in which carbon nanotubes are aggregated and bundled together by attractive forces.

The term 'stretching' used in the present invention refers to a phenomenon in which carbon nanotube clusters, which are aggregated and bundled together when the electric field is applied to the carbon nanotube cluster, are loosened in the direction of the electric field and are stretched thin and long. Indicates.

The carbon nanotube cluster may be prepared by dispersing the carbon nanotube in a polymerizable (liquid crystal) composition in an amount of 1 to 50 wt%, preferably 1 to 10 wt%, and more preferably 1 to 5 ¾. When the carbon nanotubes are less than 1 wt%, clusters may be formed in the polymerizable (liquid crystal) composition, but may not be used for the polarizing film of the present invention.

This is because the content of the carbon nano-lube cluster should be lwt% or more in order to completely block the incident light.

In addition, when the carbon nanotube cluster is more than 50wt%, some areas may be aligned and stretched when the carbon nanotube cluster is applied, but there is a problem that the alignment and stretching are not performed.

The polymerizable composition may include 0.001-5 parts by weight of a photoinitiator based on 100 parts by weight of the polymerizable material or the polymerizable liquid crystal material. A photoinitiator is a substance that absorbs energy from ultraviolet rays and initiates polymerization reaction. Although it depends on the kind, the photoinitiator plays a role of initiating photopolymerization in which the monomers, oligomers, and free radicals are added to the polymer material after curing by adding the amount of the monomers, oligomers, and free groups necessary for photopolymerization. do. The mixing ratio of photoinitiator shows a lot of difference depending on the application and equipment. Generally, the mixing ratio is about 0.1-5%. <44>

Next, the present invention includes stretching the carbon nanotube clusters in a predetermined direction by providing an electric field or a magnetic field to the engine to which the complex is applied.

In the present invention, an electric or magnetic field is used to align and stretch carbon or notube clusters mixed in the polymerizable material.

1 is a schematic diagram of an apparatus for forming a polarizing film using a polymerizable composition in which carbon nanotube clusters aligned and elongated by an electric field are mixed according to a first embodiment of the present invention.

As shown in FIG. 1, an electric field generating apparatus 100 is installed on an upper portion of a substrate 300 on which a polymerizable composition 200 on which carbon nanotube clusters are mixed is applied, and a polymerizable carbon nanotube cluster is mixed. A horizontal electric field can be applied to the composition. In this case, the carbon nanotube clusters may be stretched by aligning the carbon nanotube clusters controlled to a certain size by a horizontal electric field above a threshold voltage in one direction and applying a horizontal electric field higher than the applied voltage.

The transmittance of light may be controlled by the intensity of the electric or magnetic field applied to the polymerizable composition. The strength of the applied electric field or magnetic field may be greater than or equal to the threshold electrode field of the carbon nanotube cluster and less than the breaking electric field, and preferably greater than the threshold electric field or less than the maximum electric field.

Threshold electric field, which is a term used in the present invention, refers to an electric field in which a cluster of clusters starts to increase when a voltage is applied to the carbon or notube cluster in a fluid. The rupture electric field represents an electric field in which carbon nanotube bulsters increase in proportion as the voltage is continuously increased, but the carbon nanotube cluster breaks at any moment.

The maximum electric field is an electric field in which the length of the carbon nanotube cluster is maximum. The maximum electric field exhibits a lower value than the breaking electric field, that is, the cluster is no longer stretched even after the maximum electric field is applied, and the carbon nanotube cluster is destroyed when the maximum electric field is raised.

The threshold electric field, the breaking electric field and the maximum electric field may have different values depending on the type, content, and type of polymerizable material of the carbon nanotubes. For example, in the case of carbon nanotube clusters formed by dispersing double-walled carbon nanotubes in a polymerizable liquid crystal material at lwt¾ concentration, the threshold electric field may be about 1.5 V / im, and the maximum electric field may be 6 V // im.

In the polarizing film manufactured according to the present invention, the transmittance of light becomes maximum when the intensity of the applied electric field is in the vicinity of the maximum electric field or the breaking electric field, and almost transmits the light in the threshold electric field. Can not be exceeded. That is, by adjusting the length (width) of the carbon nanotube cluster by the intensity of the electric field can be changed the transmittance or intensity of the polarized light.

On the other hand, since the applied horizontal electric field is a force field formed by the distribution and movement of + charges and-charges, there is a difference in the properties of fluxes that determine the direction and the strength of the field, which are almost similar. Although the embodiments and drawings of the present invention have been described based on the electric field, since the electric field and the magnetic field are generated in mutually orthogonal directions, and have similar properties, the application of the embodiment and description of the electric field to the magnetic field is polymerization. It will be apparent to those skilled in the art in view of the fact that the orientation of the composition is in the orthogonal direction relative to the electric field in the case of a magnetic field.

The method of manufacturing a polarizing film according to the present invention may be applied to a roll-to-roll process, and in this case, the substrate may be characterized as having a long film form. The long film form means a continuous film having a constant width, and means a continuous film that can be supplied in the form wound with. Film is continuous in roll-to-roll process

Since they move in a constant manner, it can be seen that a constant electric or magnetic field is applied to the entire film regardless of the intensity distribution of the electric or magnetic field.

When the manufacturing method of the polarizing film according to the present invention is applied to a sheet-shaped substrate, there is a problem in that an electric field or a magnetic field does not occur in the portion directly above the electrode or the magnet of the electric field or the magnetic field generating device. Therefore, when the substrate is in the form of a sheet, it is preferable to repeat the generation of electric or magnetic fields.

2 shows a schematic diagram of an electric field generating device according to a first embodiment of the present invention when the substrate is in the form of a sheet. When the electrodes of the electric field generating device are alternately connected as shown in FIG. 2, the carbon nanotube clusters corresponding to the portions in which the electric field is not generated directly on the electrode 102 are aligned and elongated to polymerize the polymerizable liquid crystal composition to form a film. can do.

FIG. 3 is an electric field distribution diagram generated when voltage is alternately applied in the electric field generator of FIG. 2. As shown in FIG. 3, a horizontal electric field 400 generated by alternately applying a voltage to the electric field generator of FIG. 2 is a substrate coated with a polymerizable liquid crystal composition in which carbon or notube clusters located under the electric field generator are mixed. It is evenly distributed over the entire area, so that carbon nanotube clusters can be aligned and stretched over the whole area.

An apparatus for generating an electric or magnetic field may be located above or below the substrate.

<61> Next, the present invention includes a curing step. The curing step is to provide heat or light to the mixture to cure the polymerizable material. By the curing step, the polymer material is cured while polymer polymerization occurs. The polymerizable material is cured to form a binder of the film, and carbon nanotube clusters are fixed by the binder to maintain an elongated state.

Figure 4 shows a schematic diagram of the manufacturing process of the polarizing film when the substrate is in the form of a sheet (sheet). The electric field generating device is manufactured by forming a pattern electrode on a substrate. In addition, the polymerizable liquid crystal composition in which carbon nanotubes are mixed is coated on a substrate for a polarizing film. The electric field generating device is positioned on the upper or lower portion of the substrate coated with the polymerizable liquid crystal composition in which carbon nanotubes are mixed, and then horizontal electric fields are alternately applied to align and extend the carbon nanotube clusters mixed in the polymerizable liquid crystal composition. . The polarizing film is prepared by curing ultraviolet ray irradiation or heat to the polymerizable liquid crystal composition layer in which the entire carbon nanotube clusters are evenly aligned and elongated, and curing the polymerizable liquid crystal composition layer in which the carbon nanotube clusters are mixed.

5 shows a schematic view of the completed polarizing film. As shown in FIG. 5, the carbon nanotube clusters are evenly aligned and stretched in all regions in one direction by an applied horizontal electric field, and the polymerizable liquid crystal composition is integrated and aligned and stretched in one direction. It is fixed and filmed.

The substrate usable in the present invention is preferably a substrate having optical transparency of 8 or more, and includes polyether sulfone (PES), polylide (Pl), cyclo olefin polymer (C0P), polyethylene terephthalate (PEK), and tri acetyl cellulose (TAC). , PC (poly carbonate) and glass may be selected from the group consisting of. The defined materials are materials generally available in the art, and are not fixed conditions for materials that can be easily changed and used by those skilled in the art.

In the present invention, the coating of the polymerizable liquid crystal composition in which the carbon nanotube clusters are mixed may include spin, comma, gravure, dip, slot die, and silk. It can be carried out by applying a known coating process such as a screen (silk screen), inkjet printing (inkjet printing). Curing conditions vary depending on the properties of the polymerizable liquid crystal material.

The carbon nanotube polarizing film prepared according to the present invention includes a carbon nanotube cluster fixed by curing the polymerizable material to form a binder of the film and extending in one direction.

As described above, the polarizing film is burnt at an intensity of an electric or magnetic field. The length (width) of the sonanotube clusters can be adjusted to change the transmittance or intensity of the polarized light.

In addition, since the polarizing film of the present invention can control the polarization of light by using an electric field or a magnetic field, unlike the conventionally stretched polarizing plate, it is possible to realize a very high process speed and a more simplified process line construction. Therefore, the cost is reduced.

In addition, the polarizing film of the present invention, since the polarizing material is an inorganic material, the temperature limitability is improved to 150 ^° C or more compared with the conventional polarizing plate, thereby extending the operating temperature range of the display.

The present invention relates to a liquid crystal display device in which the polarizing film is coated inside or outside. Therefore, the liquid crystal display device of the present invention can prevent the generation of a defective rate due to dust or the like, compared to a film type polarizing plate using a conventional adhesive.

<72>

All simple modifications and variations of the present invention fall within the scope of the present invention, and the specific scope of the present invention will be apparent from the appended claims. Industrial Applicability

The present invention can be used in the liquid crystal display device manufacturing industry.

<75>

Claims

[Range of request]

[Claim 1]

Mixing and applying carbon nanotube clusters and the polymerizable material onto the substrate; Stretching the carbon nanotube clusters in a predetermined direction by providing an electric or magnetic field to the substrate coated with the mixture; and

A method of producing a carbon nanotube polarizing film comprising the step of providing heat or light to cure the polymerizable material.

[Claim 21]

The method of claim 1, wherein the polymerizable material is a liquid crystal compound having an acryl group, a vinyl ether group, or an epoxide functional group.

[Claim 3]

The method of manufacturing a carbon nanotube polarizing film of claim 1, wherein the polymerizable material is a polymer that is cured by heat or ultraviolet rays or monomers thereof.

[Claim 4]

The method of claim 3, wherein the polymer is a triacetyl cellulose (TAC), a polyacryl group (Polyacryl group), polyolefine (PO), polycarbonate (PC), polyethylene terephthalate (Polyethylene Telephthalate; PET), polypropylene (Polypropylene; PP), polyethylene (Polyethylene, PE) and a method for producing a carbon nanotube polarizing film, characterized in that selected from monomers thereof.

[Claim 5]

The method of claim 1, wherein the device for generating an electric or magnetic field is located on the upper or lower portion of the substrate.

[Claim 6]

The method of claim 1, wherein the strength of the electric field or the magnetic field provided to the mixture is less than a threshold electrode field of the carbon nanotube cluster.

[Claim 7]

The method of claim 1, wherein the substrate is in the form of a long film.

[Claim 81]

The carbon of claim 1, wherein the substrate is in the form of a sheet. Method for Producing Nanotube Polarizing Film.

[Claim 9]

The method of claim 1, wherein the carbon nanotubes are contained in the mixture in an amount of 1 to 50%.

[Claim 10]

The method of claim 6, wherein when the substrate is in the form of a sheet, a method for producing a carbon nanotube polarizing film, characterized in that the electric device or the magnetic field generating device is alternately connected.

[Claim 11]

11. A carbon nanoleuze polarizing film prepared according to any one of claims 1 to 10, wherein the polarizing film is a binder in which a polymerizable material is cured, and a carbon nanotube crust drawn in one direction and fixed to the binder. Carbon nanotube polarizing film comprising a.

[Claim 12]

A liquid crystal display device comprising the carbon nanotube polarizing film formed by any one of claims 1 to 10, wherein the polarizing film is formed by being coated inside or outside the liquid crystal display device.