KR20090023998A - Polarizer including carbon nano tube and preparing thereof - Google Patents

Abstract

A manufacturing method of polarized light device is provided to exclude multi-layer consisting of protective film and to reveal functionality as monolayer structure. A manufacturing method of polarized light device(100) comprises steps of: precipitating and filtering acid and carbon nanotube(130) at a weight ratio of 0.1:9.9 - 9.9:0.1 at room temperature for 10 minutes - 150 hours; washing filtered matter with distilled water several time, drying it and forming a plurality of carboxylate group, nitrate group and sulfoxide group; forming and extruding the plurality of carboxylate group, nitrate group and sulfoxide group at surface through the acid treatment with resin(110); and drawing extruded product.

Description

 Polarizer including carbon nanotube and manufacturing method thereof {Polarizer including carbon nano tube and preparing}

The present invention relates to a polarizer comprising a carbon nanotube and a method for manufacturing the same, in particular, easy to manufacture and mounting, as well as excellent polarization with an optical substrate due to its long-term reliability, and a method for manufacturing the same.

The polarizer has a function of transmitting and shielding light and has a switching function of light in a liquid crystal display (LCD), and thus may be regarded as a basic component. In addition to the field of application of this LCD, small devices such as electronic calculators and wristwatches of early development, recently, such as laptop personal computers, word processing, liquid crystal color projectors, in-vehicle navigation systems, liquid crystal televisions, personal phones, and indoor and outdoor measurement equipment. It spreads widely, there are few stains more than a conventional product, and the polarizer of a large area is calculated | required.

Conventional flat film was prepared by dyeing a polyvinyl alcohol (PVA) film polarizer 20 with iodine or dichroic dye as shown in Figure 1 and including a protective film 10 on one or both sides.

Recently, display apparatuses have been required to have improved visual characteristics, and accordingly, polarizers are required to have increased optical isotropy. It is important that the optical isotropy is small in retardation, expressed by the product of the birefringence and the thickness of the optical film.

Various attempts have been proposed as part of such an improvement effort. In Korean Patent Laid-Open No. 2004-0105583, dihydroxy compounds having a specific structural formula and dihydroxy compounds having a dimethanol structure, and carbonates from carboxylic acid diesters A polarizing sheet using a polycarbonate resin composition obtained by blending a polycarbonate resin obtained by bond formation and a polycarbonate resin obtained by carbonate bond formation from bisphenol A and carboxylic acid diester or phosgene has been proposed. The proposed technique relates to manufacturing a polarizing sheet by manufacturing a polycarbonate resin composition by a melt extrusion method and then attaching a known polarizing film to the polycarbonate resin. From the viewpoint of the polarizing film, the polycarbonate resin simply serves as a protective film. It is not much different from the conventional method.

In addition, Korean Patent Laid-Open No. 2006-0092737 discloses a carbon nanotube film chemically surface-treated to provide a carbon nanotube film having optical transparency in a visible light region as a patent on a film composed of carbon nanotubes and a method of manufacturing the same. A carbon nanotube bundle is deposited on a substrate using a Langmuir-Blodgett method to provide a uniform or patterned carbon nanotube film and a method of manufacturing the same. The carbon nanotubes manufactured as described above are very thin and uniform enough to be conductive and transparent, and the carbon nanotubes are oriented in one direction at a high density, but it is indicated that they can be used in electronic devices, sensors, displays, etc. In addition to being able to manufacture on a small scale in a very limited place, not only commercial production is impossible, but also the durability of the membrane is weak, making it difficult to secure reliability as a material.

 In addition, Korean Patent Laid-Open Publication No. 2007-0028304 uses a pigment composition for anisotropic dye films containing a pigment and a compound selected from the group consisting of an acidic group, a basic group and a neutral group and having at least two groups containing at least one basic group. The content about the formed anisotropic dye film and the polarizer using such a dye film is disclosed. However, the compound according to the present invention is water-soluble and can be processed only in an aqueous solution state, and thus has a disadvantage in that heat processing is not possible due to weak heat resistance as in the conventional polarizing film impregnated with iodine in an aqueous solution in polyvinyl alcohol resin. In addition, there is a problem in that the production cost is high by applying a pigment that is more expensive than the conventional polarizing film has a low productivity.

Therefore, it is possible to commercially produce a conventional large-scale extrusion kneader and stretching machine beyond the limitation of manufacturing on a small scale, and unlike a polarizing sheet manufactured by applying a polarizing film and a polycarbonate as a permanent protective film, There is a demand for a polarizer which is not necessary, and a technology for easily obtaining a polarizing film through melt extrusion through a water-soluble manufacturing process is eagerly desired.

SUMMARY OF THE INVENTION In order to solve the above problems, an object of the present invention is to provide a polarizer having excellent thermal stability and easy processability and a method of manufacturing the same.

It is another object of the present invention to provide a polarizer capable of expressing functionality as a single layer structure, excluding a multilayer structure made of a protective film, and a method of manufacturing the same.

In addition, another object of the present invention is to provide a polarizer having improved polarization and durability and improved productivity and a method of manufacturing the same.

In order to achieve the above object, the present invention provides a polarizer in which the weight ratio of carbon nanotubes and acids is set to 0.1: 9.9 to 9.9: 0.1 for 10 minutes to 150 hours at reflux or at room temperature, followed by filtration. Washing the filtrate with distilled water several times until the filtrate is neutral and dried to form a plurality of carboxylate groups, nitrate groups, or sulfoxide groups on the surface of the carbon nanotubes; Kneading and extruding carbon nanotubes formed with a plurality of carboxylate groups, nitrate groups, or sulfoxide groups on the surface through an acid treatment with a resin which may be a substrate during extrusion processing; And it provides a method of manufacturing a polarizer comprising the step of uniaxially stretching the extrudate.

In the present invention, the resin is a thermoplastic resin polycarbonate (PC), polyethylene terephthalate (PET), amorphous polyethylene terephthalate (APET), polypropylene terephthalate (PPT), polynaphthalene terephthalate (PEN), polyethylene tere Phthalate glycerol (PETG), polycyclohexylenedimethylene terephthalate (PCTG), modified triacetylcellulose (TAC), cycloolefin polymer (COP), cycloolefin copolymer (COC), dicyclopentadiene polymer (DCPD), Copolymer obtained by mixing at least one plastic resin such as cyclopentadiene polymer (CPD), polymethyl methacrylate (PMMA), polyimide (PI), polyarylate (PAR), silicone resin, fluorine resin, modified epoxy resin Or it provides the manufacturing method of the polarizer which is blended resin.

In the present invention, as the type of the acid, conventional acids such as sulfuric acid, hydrochloric acid and nitric acid can be used.

In another aspect, the present invention provides a method for producing a polarizer of the extrusion temperature is 150 ℃ to 350 ℃, preferably 180 ℃ to 320 ℃.

In another aspect, the present invention provides a method of manufacturing a polarizer further comprises a heat stabilizer, an antioxidant, a surfactant, a dye or a pigment in the resin mixture when kneading.

The present invention also provides a method of manufacturing a polarizer having the draw ratio of 2 to 8 times, preferably 4 to 6 times.

In addition, in the method of manufacturing a polarizer, 2g of carbon nanotubes are left in a mixed acid of nitric acid and sulfuric acid for 3 hours at room temperature, filtered through a filter, and several times with distilled water until the pH of the water exiting the filter is neutral. After washing, the carbon nanotubes were dried for 3 hours and acid-treated; 1g of the carbon nanotubes were put in a twin screw compression kneader with 1 kg of polycarbonate, and the chips were put in a single screw extruder and extruded at 300 ° C .; It provides a method of manufacturing a polarizer formed by stretching 2 to 8 times through a uniaxial stretching machine.

In another aspect, the present invention provides a polarizer comprising a carbon nanotube formed of a single layer, acid-treated on a substrate made of a uniaxially stretched polymer resin, a plurality of carboxylate groups, nitrate groups or sulfoxide groups introduced on the surface .

In the present invention, the resin is a thermoplastic resin polycarbonate (PC), polyethylene terephthalate (PET), amorphous polyethylene terephthalate (APET), polypropylene terephthalate (PPT), polynaphthalene terephthalate (PEN), polyethylene tere Phthalate glycerol (PETG), polycyclohexylenedimethylene terephthalate (PCTG), modified triacetylcellulose (TAC), cycloolefin polymer (COP), cycloolefin copolymer (COC), dicyclopentadiene polymer (DCPD), Copolymer obtained by mixing at least one plastic resin such as cyclopentadiene polymer (CPD), polymethyl methacrylate (PMMA), polyimide (PI), polyarylate (PAR), silicone resin, fluorine resin, modified epoxy resin Or a polarizer which is a blended resin.

In another aspect, the present invention provides a polarizer further comprises a heat stabilizer, an antioxidant, a surfactant, a dye or a pigment in the resin.

The present invention also provides a polarizer having the draw ratio of 2 to 8 times, preferably 4 to 6 times.

The present invention also provides a polarizer produced by the above method.

The present invention also provides a polarizer produced by the method or a polarizer in the form of a film or sheet.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. First, it should be noted that in the drawings, the same components or parts denote the same reference numerals as much as possible. In describing the present invention, detailed descriptions of related well-known functions or configurations are omitted in order not to obscure the subject matter of the present invention.

As used herein, the terms "about", "substantially", and the like, are used at, or in close proximity to, numerical values when manufacturing and material tolerances inherent in the meanings indicated are intended to aid the understanding of the invention. Accurate or absolute figures are used to assist in the prevention of unfair use by unscrupulous infringers.

Figure 2 shows a manufacturing process according to a preferred embodiment of the present invention, the present invention step S100 to obtain an acid treated carbon nanotubes; Putting the acid treated carbon nanotubes together with the molten plastic plastic in an extruder kneader and extrusion dispersing; It relates to a method comprising the step S300 to obtain a uniaxially stretched polarizing film by uniaxially stretching the extruded thermoplastic resin.

  Polarizer according to an embodiment of the present invention may be prepared by acid treatment of carbon nanotubes to introduce a carboxylate group to the tube, and kneaded with the polymer resin and extruded, followed by uniaxial stretching.

Specifically, the present invention will be described in detail by dividing step by step as follows.

Acid treatment step (S100)

The polarizer according to the present invention is acid treated with carbon nanotubes such that a large amount of carboxylate groups, nitrate groups or sulfate groups are present on the surface of the carbon nanotubes. Carbon nanotubes used in the present invention is not particularly limited to the kind, and may be prepared by arc discharge method, laser ablation method, high temperature filament plasma chemical vapor deposition method, microwave plasma chemical vapor deposition method, thermochemical vapor deposition method or pyrolysis method. have. However, since carbon nanotubes contain carbon by-products such as by-products such as amorphous carbon and fullerene and transition metals used as catalysts for growth of tubes, a separate purification step is required to remove them. Preferably, the carbon nanotubes are refluxed in distilled water at 100 ° C. for about 10 hours to 24 hours or left at room temperature, filtered, dried, washed with toluene, and by-products are removed. Thereafter, the obtained material is heated at about 470 ° C. for 20 to 30 minutes and washed with 5 to 7 moles of acid to remove all the by-products and obtain pure carbon nanotubes.

  Acid treatment can be carried out in strong acids refluxing carbon nanotubes. For example in solution of nitric acid, sulfuric acid or mixtures thereof.

  Specifically, the weight ratio of the carbon nanotubes and the acid is deposited at reflux or at room temperature for 10 minutes to 150 hours in a mixed acid solution of nitric acid and sulfuric acid of 0.1: 9.9 to 9.9: 0.1, and preferably 0.1 μm to 0.4 μm. After filtration with a polycarbonate filter of ㎛ and the filtrate is washed repeatedly with distilled water several times until the filtered water is neutral. The filtrate thus obtained is put in a vacuum dryer and dried for 1 to 24 hours to obtain an acid treated carbon nanotube. Carboxylation of carbon nanotubes in the present invention can be confirmed by Raman spectrum or the like.

Kneading, extrusion step (S200)

  Carbon nanotubes in which a plurality of carboxylate groups, nitrate groups, or sulfoxide groups are formed on the surface through acid treatment may be used as resins, for example, polycarbonate (PC), polyethylene terephthalate ( PET), Amorphous Polyethylene Terephthalate (APET), Polypropylene Terephthalate (PPT), Polynaphthalene Terephthalate (PEN), Polyethylene Terephthalate Glycerol (PETG), Polycyclohexylenedimethylene Terephthalate (PCTG), Modified Tree Acetylcellulose (TAC), cycloolefin polymer (COP), cycloolefin copolymer (COC), dicyclopentadiene polymer (DCPD), cyclopentadiene polymer (CPD), polymethyl methacrylate (PMMA), polyimide ( The same applies to copolymers or blended resins in which one or more plastic resins such as PI), polyarylate (PAR), silicone resins, fluororesins, and modified epoxy resins are mixed. The above carbon nanotubes can be applied.

  The device for uniformly mixing the acid treated carbon nanotubes and the above resin may use a conventional twin screw extrusion kneader, and the processing temperature should determine the optimum extrusion temperature according to the type of the resin. Usually 150 degreeC-350 degreeC, Preferably 180 degreeC-320 degreeC is suitable. When the temperature is 150 ° C. or less, the resin is not extruded due to the viscosity characteristic. At 350 ° C. or more, the resin is thermally decomposed to degrade performance.

Chips obtained by cutting the resin out through the extruder kneader into appropriate sizes are placed in a single screw extruder, or a twin screw extruder and a single screw extruder are continuously mounted to form a film or sheet having a uniform thickness.

Meanwhile, the kneading resin mixture may optionally further include other heat stabilizers, antioxidants, surfactants, pigments, pigments, and the like.

Uniaxial drawing step (S300)

  The compressed film or sheet is then stretched in the uniaxial direction using a uniaxial stretching machine. At this time, the stretching ratio is 2 to 8 times, preferably 4 to 6 times. If the draw ratio is 2 times or less, the polarization characteristics are not realized. If the draw ratio is 8 times or more, crease or crack occurs in the film, and the film is severely cut and cannot be used.

As described above, the polarizer and the method of manufacturing the same according to an embodiment of the present invention not only eliminates the inconvenience of using a large-scale facility for impregnating iodine on a polyvinyl alcohol (PVA) film, and after iodine impregnation. It is possible to form a single layer by improving the method of using triacetyl cellulose (TAC) as a permanent protective film has the advantage of very improved productivity.

In addition, the polarizer and the manufacturing method thereof according to the present invention has excellent thermal stability of the product while exhibiting polarization characteristics and fewer defects, and thus have excellent reliability.

Accordingly, the polarizer according to the present invention may be applied to liquid crystal display (LCD) and organic light emitting diode (OLED) optical filters, light shielding panels for automotive instrument panels, exterior light shielding panels for buildings, and decorative panels.

  Hereinafter, the present invention will be described in detail by way of examples.

Example 1

2g of carbon nanotubes (ILJIN CNT AP grade ^TM ) are left in a mixed acid of nitric acid and sulfuric acid at room temperature for 3 hours, filtered through a filter, and washed several times with distilled water until the pH of the water flowing through the filter is neutral. The obtained carbon nanotubes are dried in a vacuum oven for 3 hours to obtain acid treated carbon nanotubes. 1 g of the carbon nanotubes obtained above was put into a twin screw compression kneader with 1 kg of polycarbonate (LG Dow Polycarbonate CARIBRE 200) to prepare a black chip. The chip obtained here was placed in a uniaxial extruder, and the film was extruded at 300 ° C., and then stretched four times through a uniaxial stretching machine to prepare a 75 μm thick polarizing film.

Example 2

2g of carbon nanotubes (ILJIN CNT AP grade ^TM ) are left in a mixed acid of nitric acid and sulfuric acid at room temperature for 3 hours, filtered through a filter, and washed several times with distilled water until the pH of the water flowing through the filter is neutral. The obtained carbon nanotubes are dried in a vacuum oven for 3 hours to obtain acid treated carbon nanotubes. 1 g of the carbon nanotubes obtained above was put into a twin screw compression kneader with 1 kg of polycarbonate (LG Dow Polycarbonate CARIBRE 200) to prepare a black chip. The chip obtained here was placed in a uniaxial extruder, and the film was extruded at 280 ° C., and then stretched five times through a uniaxial stretching machine to prepare a 75 μm thick polarizing film.

Example 3

2g of carbon nanotubes (ILJIN CNT AP grade ^TM ) are left in a mixed acid of nitric acid and sulfuric acid at room temperature for 3 hours, filtered through a filter, and washed several times with distilled water until the pH of the water flowing through the filter is neutral. The obtained carbon nanotubes are dried in a vacuum oven for 3 hours to obtain acid treated carbon nanotubes. 2 g of carbon nanotubes obtained above were put into a twin screw compression kneader with 1 kg of polycarbonate (LG Dow Polycarbonate CARIBRE 200) to prepare a black chip. The chip obtained here was placed in a single screw extruder, and the film was extruded at 280 ° C., and then drawn six times through a single screw drawing machine to prepare a 75 μm-thick polarizing film.

Comparative Example 1

  Polyvinyl alcohol film having a thickness of 75 μm [Kuraray Co., Ltd.] Vinylon # 7500] of the product was stretched 5 times along the vertical axis to obtain a polarizing film substrate. The polyvinyl alcohol film was immersed in a 70 ° C. aqueous solution prepared with 5% by weight of glycerol, 15% by weight of iodine, and 80% by weight of deionized water while maintaining tension. This was washed with water for 20 seconds and dried at 50 ° C. to obtain a polarizing film.

Comparative Example 2

 Polyvinyl alcohol film having a thickness of 75 μm [Kuraray Co., Ltd.] Vinylon # 7500] of the product was stretched 5 times along the vertical axis to obtain a polarizing film substrate. The polyvinyl alcohol film was immersed in a 70 ° C. aqueous solution prepared with 5% by weight of glycerol, 15% by weight of azo dye (C.I. Direct Orange 39), and 80% by weight of deionized water while maintaining tension. This was washed with water for 20 seconds and dried at 50 ° C. to obtain a polarizing film.

Comparative Example 3

  Polyvinyl alcohol film having a thickness of 75 μm [Kuraray Co., Ltd.] Vinylon # 7500] of the product was stretched 5 times along the vertical axis to obtain a polarizing film substrate. The polyvinyl alcohol film was immersed in a 70 ° C. aqueous solution prepared with 5% by weight of glycerol, 15% by weight of azo dye (C.I. Direct Red 117), and 80% by weight of deionized water while maintaining tension. This was washed with water for 20 seconds and dried at 50 ° C. to obtain a polarizing film.

* Assessment Methods

1. Thermal reliability

  The degree of polarization at the absorption wavelength (λ = 610) of the polarizing films obtained in the above Examples and Comparative Examples was measured. The relationship between absorbance before and after leaving for 2400 hours under conditions of 100 ° C. is defined by the following equation.

ΔA (%) = ((A (2400) / A (0)) X 100

Here, the value of the absorbance in 0 hours is represented by A (0), and the absorbance after 2400 hours is represented by A (2400). Larger ΔA means better thermal reliability.

   2. Number of defects

  Observation was performed at the extinction position using a polarization microscope Nikon Optiphot-POL and using a 100-fold objective and a 10-fold eyepiece.

  (Circle) when there are no defects, (triangle | delta) when the number of defects is 1-3, and X when the number of defects is three or more.

Table 1 shows the results of Examples and Comparative Examples.

division Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Heat-resistant reliability 99.8% 99.5% 99.4 88.1% 85.7% 86.6% Defects ○ ○ ○ X △ △

The present invention described above is not limited to the above-described embodiment and the accompanying drawings, and various substitutions, modifications, and changes are possible within the scope without departing from the technical spirit of the present invention. It will be evident to those who have knowledge of.

1 is a cross-sectional view of a polarizer according to the prior art.

Figure 2 is a manufacturing process of the polarizer according to an embodiment of the present invention.

Figure 3 is a schematic cross-sectional view of a polarizer according to an embodiment of the present invention.

<Description of Major Symbols in Drawing>

100: polarizer 110: polymer resin

130: carbon nanotubes

Claims (12)

In the manufacturing method of a polarizer, The weight ratio of carbon nanotubes and acid was 0.1: 9.9 to 9.9: 0.1, and the mixture was deposited at reflux or room temperature for 10 minutes to 150 hours and filtered, and the filtrate was washed several times with distilled water until the filtered water became neutral. And then drying to form a plurality of carboxylate groups, nitrate groups, sulfoxide groups on the surface of the carbon nanotubes; Kneading and extruding carbon nanotubes formed with a plurality of carboxylate groups, nitrate groups, and sulfoxide groups on the surface through an acid treatment with a resin which may be used as a base material during extrusion; And A method of manufacturing a polarizer comprising the step of uniaxially stretching the extrudate. The method of claim 1, The resin is a thermoplastic resin polycarbonate (PC), polyethylene terephthalate (PET), amorphous polyethylene terephthalate (APET), polypropylene terephthalate (PPT), polynaphthalene terephthalate (PEN), polyethylene terephthalate glycerol (PETG) ), Polycyclohexylenedimethylene terephthalate (PCTG), modified triacetylcellulose (TAC), cycloolefin polymer (COP), cycloolefin copolymer (COC), dicyclopentadiene polymer (DCPD), cyclopentadiene polymer Copolymers or blended resins of one or more plastic resins such as (CPD), polymethyl methacrylate (PMMA), polyimide (PI), polyarylate (PAR), silicone resin, fluorine resin and epoxy resin. Method of manufacturing a polarizer. The method of claim 1, The extrusion temperature is 150 ℃ to 350 ℃, preferably 180 ℃ to 320 ℃ manufacturing method of the polarizer. The method of claim 1, The method of manufacturing a polarizer further comprises a heat stabilizer, an antioxidant, a surfactant, a dye or a pigment in the resin mixture when kneading. The method of claim 1, The draw ratio is 2 to 8 times, preferably 4 to 6 times the manufacturing method of the polarizer. In the manufacturing method of a polarizer, 2g of carbon nanotubes were left in a mixed acid of nitric acid and sulfuric acid at room temperature for 3 hours, filtered through a filter, washed several times with distilled water until the pH of the water exiting the filter was neutral, and then the carbon nanotubes were washed for 3 hours. Dried to acidic; 1g of the carbon nanotubes were put in a twin screw compression kneader with 1 kg of polycarbonate, and the chips were put in a single screw extruder and extruded at 300 ° C .; Method of manufacturing a polarizer formed by stretching 2 to 8 times through a uniaxial stretching machine. Formed in a single layer, A polarizer comprising a carbon nanotube in which a plurality of carboxylate groups, nitrate groups or sulfoxide groups are introduced to a surface by acid treatment to a substrate made of a uniaxially stretched polymer resin. The method of claim 7, wherein The resin is a thermoplastic resin polycarbonate (PC), polyethylene terephthalate (PET), amorphous polyethylene terephthalate (APET), polypropylene terephthalate (PPT), polynaphthalene terephthalate (PEN), polyethylene terephthalate glycerol (PETG) ), Polycyclohexylenedimethylene terephthalate (PCTG), modified triacetylcellulose (TAC), cycloolefin polymer (COP), cycloolefin copolymer (COC), dicyclopentadiene polymer (DCPD), cyclopentadiene polymer Copolymers or blended resins of one or more plastic resins such as (CPD), polymethyl methacrylate (PMMA), polyimide (PI), polyarylate (PAR), silicone resin, fluorine resin and epoxy resin. Polarizer. The method of claim 7, wherein The resin is a polarizer further comprises a heat stabilizer, antioxidant, surfactant, pigment or pigment. The method of claim 7, wherein The draw ratio is 2 to 8 times, preferably 4 to 6 times the polarizer. The polarizer manufactured by the method of any one of Claims 1-6. The polarizer produced by the method of any one of claims 1 to 6 or the polarizer of any one of claims 7 to 10 is a polarizer in the form of a film or sheet.

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