TWI441776B - Fabrication method of electroconductive thin film of carbon nanotubes with excellent flexibility - Google Patents

Description

Method for manufacturing nanometer carbon tube conductive film with excellent flexibility

The present invention relates to a method for producing a conductive film, and more particularly to a method for producing a carbon nanotube conductive film having excellent flexibility.

With the wide application and development of LCD screens, the development of transparent conductive materials has been a hot research topic. The transparent conductive films used in displays and touch panels should have the following basic characteristics: (1) Light transmittance in the visible range Both high conductivity and (2) must be made into a smooth surface film and can withstand the plasma process environment, (3) easy to etch to form a predetermined pattern, (4) large area uniformity (5) low production cost, (6) non-toxic and capable of recycling. Indium tin oxide (ITO) has the characteristics of low film specific resistance and visible light transmittance of 80% to 90%, and has become the most important raw material source of transparent conductive film, but in ITO raw materials. Indium is a rare metal with limited production, resulting in unstable supply and high raw material costs. Therefore, the development of new alternative materials has become a major issue. In addition, the touch panel and the flexible panel which have been actively invested in the industry in recent years have disadvantages in that the ITO film is relatively soft and relatively durable in use and relatively low in reliability.

In view of the insufficient source of ITO and its application limit, nanocarbon tubes are a popular alternative material developed recently, mainly because of the excellent optical, electrical, magnetic and mechanical properties of nano carbon nanotube materials. Moreover, its macroscopic physical properties and chemical properties are directly related to the microscopic arrangement and quantity of the materials themselves, and can affect the applicable product end. At present, single-walled carbon nanotubes (single) that can be put into commercial application have been developed. -walled carbon nanotubes (referred to as SWNT) conductive film.

The single-walled carbon nanotube conductive film is mainly made by a filter method and a spray method. Among them, the filter method is to first synthesize SWNT by laser, pickle it with a high concentration of nitric acid solution, add it to a solvent containing a specific surfactant to form a carbon nanotube solution, and then filter it with a specific filter paper. The carbon nanotubes are parked on the surface of the filter paper to form a carbon nanotube membrane, and then the carbon nanotube membrane is attached to the transparent substrate, and the filter paper portion is removed by acetone, leaving only the carbon nanotubes. , a single-walled carbon nanotube conductive film ("Transparent, Conductive Carbon Nanotube Films", Z. Wu et., Science 2004, 305, 1273, "Effect of SOC12 Treatment on Electrical and Mechanical Properties of Single- Wall Carbon Nanotube Networks", U. Dettlaff-Weglikowska et., J. Am. Chem. Soc., 2005, 127, 5125-5131).

The method for preparing a single-walled carbon nanotube conductive film by spraying method is to add a predetermined amount of single-walled carbon nanotubes to a solvent containing a specific surfactant to form a carbon nanotube solution, and After centrifugation of the carbon nanotube solution, a 50% portion of the upper layer of the solution is sprayed onto a poly(ethylene terephthalate, abbreviated as PET) substrate having a surface temperature maintained at 100 ° C, and then A single-walled carbon nanotube conductive film ("Effect of Acid Treatment on Carbon Nanotube-Based Flexible Transparent Conducting Films", J. Am. Chem. Soc., 2007, 129) can be obtained by washing and drying with deionized water. , 7758-7759).

Although the academic and industry's active research and development, has developed a variety of transparent conductive films, and the manufacturing technology of single-walled carbon nanotube conductive film has also entered the stage of commercialization, and can replace the ITO film. Trends, but related process technology can not be successful in a short period of time, in response to future needs, and create more humane interface products and soft electronic products, with touch panels, flexible panels, transparent The process technology of liquid crystal displays, such as electrodes, will also change. Among them, the maturity of material technology will be a key element. Therefore, there is still a need to continuously develop different types of material technologies to provide more choices and application.

In addition to the continuous development of new, low-cost conductive film materials with transparency and conductivity, the development of flexible conductive films has received more and more attention due to the development trend of future touch panels and flexible panels. In order to achieve the standard for practical application, whether the conductive film can maintain stable resistance and conductivity after multiple deflections will become an urgent problem to be overcome, in order to improve the reliability of the conductive film after multiple deflections, in addition to In addition to developing new materials that can be applied, it is also necessary to actively improve the material properties to provide a conductive film with superior flexibility, thereby improving the quality of the final product.

Accordingly, it is an object of the present invention to provide a method for producing a highly flexible carbon nanotube conductive film which can maintain stable conductivity after repeated flexing.

Therefore, the method for producing the excellent flexible carbon nanotube conductive film of the present invention comprises the following steps:

(i) preparing a carbon nanotube solution, adding a predetermined amount of the carbon nanotube component to a predetermined amount of solvent to prepare a carbon nanotube solution having a viscosity value of 1 to 50 c.p, and the nanometer The carbon tube component has a plurality of multi-layered wall carbon nanotubes;

(ii) transparent flexible material coating, applying a transparent flexible material to a substrate sheet placed on a substrate, and rotating the substrate to make the flexible material on the substrate Forming a first cladding layer on the sheet;

(iii) atomizing, applying an ultrasonic atomization frequency to the carbon nanotube solution, atomizing the carbon nanotube solution into a plurality of atomized particles dispersed and carrying the carbon nanotubes, and providing Carrying a gas to transport the atomized particles along a predetermined path, wherein the atomized particles have a particle diameter of between 0.5 μm and 50 μm;

(iv) spin coating, directing the atomized particles onto the susceptor to which the first cladding layer has been applied, and rotating the susceptor to uniformly coat the atomized particles The first cladding layer further forms a conductive film combined with the first cladding layer.

The invention has the beneficial effects of: using the first coating layer made of flexible material on the substrate sheet, and then using the ultrasonic atomization and spin coating technology to make the carbon nanotubes The formed conductive film is coated and bonded to the first coating layer, so that the finally obtained conductive film can maintain a relatively stable conductivity after being subjected to multiple deflections, so that the invention can be manufactured with relatively high reliability. The advantage of a high-conductivity carbon nanotube conductive film with excellent flexibility.

The above and other technical contents, features and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments of the invention.

Referring to Figures 1 and 3, a first preferred embodiment of the method for producing an excellent flexible carbon nanotube conductive film of the present invention comprises the following steps: Step 101 is purification, which is respectively pickled with a high concentration hydrochloric acid solution. , precipitation washing and vacuum drying to purify a plurality of multi-walled carbon nanotubes in a carbon nanotube component, the main purpose of the purification treatment is to remove iron oxide and amorphous carbon in the carbon nanotube raw materials. The surface functional groups or the like are adhered or mixed with impurities in the carbon nanotube raw materials to improve the conductivity of the multilayered carbon nanotubes, thereby enabling the carbon nanotubes to exhibit better photoelectric properties.

Step 102 is to prepare a carbon nanotube solution 20, and add 1 part by weight of the carbon nanotube component and 1 part by weight of the surfactant component to 1000 to 1,000,000 parts by weight of the solvent respectively to prepare a viscosity value of 1 ~50c.p of carbon nanotube solution 20, and the carbon nanotube component has a plurality of multi-layered wall carbon nanotubes.

The surfactant component is for preventing the aggregation of the multi-walled nanotubes, and is a substance selected from the group consisting of a sulfated alcohol (ROSO ₃ ^- M ⁺ ) , alkylsulfonate (formula RSO ₃ ^- M ⁺ ), α-olefin sulfonate (alpha-olefinsulphonate, abbreviated as AOS, of the formula RCH=CH(CH ₂ ) _n -SO ₃ M) Quaternary ammonium salt ), ethylene oxide (also known as polyethylene glycol, polyoxyethylene, POE for short), polyoxyethylene alkyl ether (also known as fatty alcohol polyoxyethylene ether, ether alcohol, alcohol ethoxylate, referred to as AE, The formula is RO(CH ₂ CH ₂ O) _n H), and combinations thereof.

Preferably, the surfactant is a substance selected from the group consisting of sodium C ₄ ~ C ₁₈ linear alkyl sulfonate (formula RSO ₃ ^- Na ⁺ ), C ₄ ~ C ₁₈ straight Potassium alkane sulfonate (formula RSO ₃ ^- K ⁺ ), linear alkyl sodium sulfate of C ₄ ~ C ₁₈ (formula of ROSO ₃ ^- Na ⁺ ), linear alkyl group of C ₄ ~ C ₁₈ Potassium sulfate (formula of ROSO ₃ ^- K ⁺ ), sodium C ₄ ~ C ₁₈ linear alkylbenzene sulfonate (formula RC ₆ H ₄ SO ₃ ^- Na ⁺ ), linear chain of C ₄ ~ C ₁₈ Potassium alkylbenzene sulfonate (formula RC ₆ H ₄ SO ₃ ^- K ⁺ ), linear C ₄ -C ₁₈ linear alkyl benzene sulphate (formula: ROC ₆ H ₄ SO ₃ ^- Na ⁺ ), C ₄ to C ₁₈ linear alkyl benzene sulfate (formula: ROC ₆ H ₄ SO ₃ ^- K ⁺ ), C ₂ to C ₁₆ linear alkyl quaternary ammonium salt, α-olefin sulfonate (abbreviation is the AOS, the formula _{RCH = CH (CH 2) n} -SO 3 M, where, n = 14 ~ 16, and M is an alkali metal ion group), alkyl polyoxyethylene alkyl is a C ₂ ~ C ₁₆ of Ether (abbreviated as AE, the formula is RO(CH ₂ CH ₂ O) _n H, n=5~30), and combinations thereof. Thereby, a better dispersion effect can be achieved. In the present embodiment, sodium dodecyl sulfate (SDS) is selected as the surfactant.

Wherein the solvent is a liquid selected from the group consisting of water, ethanol, isopropanol and acetone. In the preparation, after adding the multi-layered wall carbon nanotube component and the surfactant to the solvent, the probe type ultrasonic oscillating disperser with a power of 750W can be used first (model: Sonics & Materials, Inc. "SONICS VCX750") The MWNT solution was applied at 20% power for 5 minutes and 30% power for 5 minutes to prevent the multi-walled nanotubes from collecting and being uniformly dispersed.

Step 103 is a transparent flexible material coating, and a transparent flexible material is applied to a substrate sheet 21 placed on a base 22, and the flexible material is rotated by rotating the base 22. A first cladding layer 30 is formed on the substrate sheet 21.

Preferably, the first cladding layer 30 is made of a flexible material selected from the group consisting of poly (vinyl alcohol, PVA for short) and polyacrylic acid (poly (poly) Acrylic acid), abbreviated as PAA), polyethylene (poly(ethylene glycol), PEG for short), poly(methyl methacrylate) (PMMA for short), and polycarbonate (polycarbonate, Referred to as PC). In the preferred embodiment, the first cladding layer 30 is made of polyvinyl alcohol.

Step 104 is atomization, applying an ultrasonic atomization frequency to the carbon nanotube solution 20, and atomizing the carbon nanotube solution 20 into a plurality of atomized particles 23 dispersed with the carbon nanotubes. And carrying a carrier gas 24 to transport the atomized particles 23 along a predetermined path. Wherein, the carbon nanotube solution 20 is contained in an atomization container 25, and the liquid level of the solution is maintained at a fixed height by a siphon tube 26, whereby the ultrasonic wave element 27 generating the ultrasonic frequency is generated. Constantly located at a fixed depth below the liquid surface to control the energy of the liquid level of the solution is fixed, and the particle size of the atomized particles 23 produced can be maintained consistently. Wherein, the siphon tube 26 is connected between the atomization container 25 and a liquid storage container 28, and the liquid storage container 28 is placed on a lifting seat 29 to be vertically displaced by being linked, and the mist can be controlled thereby. The liquid level in the container 25.

Preferably, the ultrasonic atomization frequency is 20 kHz to 2.45 MHz. In this embodiment, the ultrasonic atomization frequency of 1.65 MHz is used. The ultrasonic atomizer used in this embodiment is: Pro-Wave Electronic Corp M165D25, M165D20, and the particle size of the atomized particles is between 0.5 μm and 50 μm, and preferably between 2 μm and 7 μm. In this embodiment, it is super The sonic atomization frequency maintains the particle diameter of the atomized particles 21 substantially at about 3 μm.

In order to meet the required particle size, the frequency range of the ultrasonic wave can be estimated by the following formula to adjust to the required atomized particle size relatively quickly:

Where D is the particle size of the atomized particles, T is the surface tension coefficient (N/cm), ρ is the solution density (g/cm ³ ), f is the ultrasonic atomization frequency (Hz), and α is 0.34. Value. (Ultrasonics Volume 22, Issue 6, November 1984, Pages 259-260)

Preferably, the flow rate of the carrier gas 24 is from 1 L/min to 200 L/min. In the present embodiment, the flow rate of the carrier gas 24 is set to 22 L/min, and the carrier gas 24 is nitrogen.

Step 105 is spin coating, guiding the atomized particles 23 to the top of the susceptor 22 to which the first cladding layer 30 has been applied, and then rotating the susceptor 22 to make the atomized particles 23 The first coating layer 30 is uniformly applied to form a conductive film combined with the first cladding layer 30.

When the rotating cloth is rotated, the low speed, the medium speed and the high speed speed of the base 22 are adjusted, and the atomized particles 23 are respectively subjected to a wet spin coating, a preliminary film forming spin coating and at least one preliminary film forming and coating. A re-filming spin coating is applied once to form a conductive film on the first cladding layer 30. When the re-filming spin coating is performed, the susceptor is sequentially rotated through a cycle of a low speed, a medium speed, and a high speed, and the ratio of the low speed, the medium speed, and the high speed speed is 2 to 3: 3~6:8~40. In this embodiment, the low speed is preferably 300 r. pm to 450 rpm, and the medium speed is preferably controlled at 450 rpm to 900 rpm, and the high speed is preferably 1200 rpm to 6000 rpm. Pm.

Step 106 is hot pressing, applying a predetermined pressure to the substrate sheet 21 containing the conductive film and the first cladding layer 30 at a predetermined temperature, so that the conductive film is compacted and compacted, and the The carbon nanotube is pressed into the first cladding layer 30 to form a tight bond with the first cladding layer 30. By forming a dense and stable structure by hot pressing, and forming a tight connection between the multi-walled carbon nanotubes, the surface resistance of the conductive film is reduced, so that the conductive film can perform better. Conductivity.

Preferably, when hot pressing is performed, a pressure of 1 to 200 kg/cm ² is applied at a temperature of 50 ° C to 110 ° C for 30 seconds to 30 minutes, and in the present embodiment, 100 kg / is applied at a temperature of 90 ° C. The pressure of cm ² was hot pressed for 10 minutes. In order to surely remove the moisture content of the PVA, when the hot pressing temperature is set to 70 ° C, the hot pressing time is not less than 10 minutes, and the best is hot pressing at a temperature of 90 ° C for 10 minutes at a pressure of 100 kg / cm ² .

Step 107 is cleaning, the substrate sheet 21 having the conductive film and the first coating layer 30 is firstly placed in deionized water for 5 to 30 minutes, and soaked for 2 hours for water, repeated 5 times, and then soaked in ethanol 2 After an hour, a vacuum is applied at a temperature of 60 ° C, whereby the surfactant remaining in the conductive films can be removed to prevent the residual impurities from causing a decrease in the conductivity of the conductive films. After the cleaning is completed and dried, a finished product of the excellent flexible carbon nanotube conductive film bonded to the substrate sheet 21 can be obtained.

Referring to FIG. 2 and FIG. 3, a second preferred embodiment of the method for manufacturing an excellent flexible carbon nanotube conductive film of the present invention comprises the following steps: Step 301 is to purify the carbon nanotube component. The multilayered wall carbon nanotubes in the middle.

Step 302 is to prepare a carbon nanotube solution 20, and add 1 part by weight of the carbon nanotube component and 1 part by weight of the surfactant component to 1000 to 1,000,000 parts by weight of the solvent respectively to prepare a viscosity value of 1 ~50c.p carbon nanotube solution 20, the ratio of the carbon nanotube component, the surfactant to the solvent, and the types of surfactants and solvents available are the same as the steps of the first preferred embodiment 102 is the same, so it will not be described again.

Step 303 is a transparent flexible material coating, and a transparent flexible material is applied to a substrate sheet 21 placed on a base 22, and the flexible material is rotated by rotating the base 22. A first cladding layer 30 is formed on the substrate sheet 21.

Step 304 is atomization, applying an ultrasonic atomization frequency to the carbon nanotube solution 20, and atomizing the carbon nanotube solution 20 into a plurality of atomized particles 23 dispersed with the carbon nanotubes. And carrying a carrier gas 24 to transport the atomized particles 23 along a predetermined path.

Step 305 is spin coating, guiding the atomized particles 23 onto the susceptor 22 to which the first cladding layer 30 has been coated, and rotating the susceptor 22 to make the atomized particles 23 The first coating layer 30 is uniformly applied to form a conductive film combined with the first cladding layer 30.

Step 306 is hot pressing, applying a predetermined pressure to the substrate sheet 21 containing the conductive film and the first cladding layer 30 at a predetermined temperature, so that the conductive film is compacted and compacted, and the The carbon nanotube is pressed into the first cladding layer 30 to form a tight bond with the first cladding layer 30.

The contents of the steps 303 to 306, including the usable substances and the various manufacturing conditions or parameters, are the same as the steps 103 to 106 of the first preferred embodiment, and therefore will not be described again.

Step 307 is cleaning. The substrate sheet 21 having the conductive film and the first coating layer 30 is firstly placed in deionized water for 5 to 30 minutes, and soaked for 2 hours for water exchange, repeated 5 times, and then soaked in ethanol 2 After an hour, a vacuum is applied at a temperature of 60 ° C, whereby the surfactant remaining in the conductive films can be removed to prevent the residual impurities from causing a decrease in the conductivity of the conductive films. It should be added that before the cleaning step, a hot pressing is required to enhance the mechanical strength of the film and to avoid damage to the film during the cleaning process.

The main difference between the second preferred embodiment and the first preferred embodiment is that after the conductive film is formed on the first cladding layer 30 by spin coating, a second film is further formed on the conductive film. Covered layer.

Step 308 forms the second cladding layer by coating a transparent flexible material onto the conductive film to form the second cladding layer. Preferably, the second coating layer is made of a flexible material selected from the group consisting of polyvinyl alcohol, polyacrylic acid, polyethylene glycol, polymethyl methacrylate, and polycarbonate. ester. In the preferred embodiment, the second coating layer is made of polyvinyl alcohol.

Wherein, in order to maintain the predetermined conductivity of the prepared conductive film, the thickness of the second cladding layer is preferably less than 30 nm, whereby the CNT can still protrude from the surface of the second cladding layer, and the resistance can be avoided. The drama has risen. Therefore, the conditions of spin coating are to prepare a PVA having a molecular weight of 27,000 to 32,000 to a concentration of 50 mg/L, and the amount of each drop is 0.25 ml, which is controlled during the formation of the first and second coating layers. The susceptor was spin-coated at 500 r. pm, 30 s, 1000 rpm, 60 s, and 6000 r. pm, 180 s. The thickness of the first and second cladding layers formed by the PVA can be controlled by the length of the spin coating time. Usually, the thickness of the first cladding layer is greater than the thickness of the second cladding layer, so that the MWNT is hot in step 306. The pressing portion can partially sink therein to form a tight bond with the first cladding layer. The second cladding layer is primarily a protective function and does not impede the conductivity of the surface, so its thickness must be thin (less than 30 nm).

Step 309 is hot pressing, applying a predetermined pressure to the substrate 21 containing the conductive film, the first cladding layer 30 and the second cladding layer at a predetermined temperature, so that the conductive film is compacted and compacted. And pressing the first cladding layer 30 and the second cladding layer against the conductive film, so that the carbon nanotubes are tightly bonded to the first and second coating layers.

It is worth noting that in order to ensure that the CNT can protrude the surface of the second coating layer, after the hot pressing is completed, the surface of the conductive film is washed by ultrasonic waves and the surface of the conductive film is washed at a rotation speed of 3000 r. PVA.

Preferably, when hot pressing is performed, a pressure of 75 to 125 kg/cm ² is applied at a temperature of 60 ° C to 90 ° C for 30 minutes, and in the present embodiment, 100 kg / cm ² is applied at a temperature of 90 ° C. The pressure was hot pressed for 10 minutes. After the hot pressing is completed, a finished product of the excellent flexible carbon nanotube conductive film bonded to the substrate sheet 21 can be obtained.

<Specific example>

(1) Purification of 1 g of multi-layered wall carbon nanotubes (MWNT): first prepare 250 ml of 6 M concentrated hydrochloric acid solution, then put 1 g of MWNT into the hydrochloric acid solution, stir for 24 hours, and then continuously wash 6 times by precipitation. Then, reconstitute 250 ml of 6M hydrochloric acid, and then continue to purify MWNT by the above-mentioned pickling and washing, so that the MWNT is purified three times at a temperature of 80 ° C, 12 hours and a temperature of 250 ° C for 24 hours. It was vacuum dried and placed in a nitrogen oven to dry at a temperature of 400 °C.

(2) Configure 10mg/L MWNT aqueous solution: Put 10mg MWNT and 10mg SDS in 1L deionized water, first use the probe 750W ultrasonic shock diffuser (model: Sonics & Materials, Inc. SONICS VCX750") The MWNT solution was applied at 20% power for 5 minutes and 30% power for 5 minutes to prevent the multi-walled nanotubes from collecting and being uniformly dispersed.

(3) Transparent flexible material coating: A polyvinyl alcohol aqueous solution is coated on a substrate sheet placed on a spin base to form a first coating layer. The substrate sheet must be cleaned before coating, by cleaning the substrate sheet on the susceptor, (i) rinsing with deionized water at a speed of 300 r. pm for 30 seconds, and rotating at 500 rpm. 40 seconds, (ii) then wash with ethanol at 800r.pm for 60 seconds, 1200r.pm for 60 seconds, (iii) finally rotate at 4000r.pm for 120 seconds, and repeat the above (i ) The steps of ~(iii) are twice. The size of the substrate sheet was 4 cm x 4 cm.

Then, the first coating layer of polyvinyl alcohol can be coated, and a 50 mg/L aqueous solution of polyvinyl alcohol (molecular weight: 27000-32000) is prepared for use, and about 5 drops of a glass dropper of PVA is added to the solution. On the substrate sheet, by controlling the rotation speed of the substrate sheet, the PVA aqueous solution respectively has different effects on the substrate sheet. First, when the rotation speed is 450 r.pm for 30 seconds to 60 seconds, the PVA aqueous solution can be condensed in the center. Rotate at a speed of 600r.pm for 15 seconds to 30 seconds to make the PVA aqueous solution expand initially, rotate at 900r.pm for 30 seconds to 45 seconds to further extend, and rotate at a speed of 4500 r.pm for 90 seconds to 180 seconds. To form the first coating film, and then rotate at a speed of 6000 r. pm for more than 120 seconds to perform preliminary drying. Finally, the first coating layer formed on the substrate sheet is placed in the oven together with the substrate sheet. And baking at a temperature of 150 ° C for 3 hours, whereby the first coating layer can be recrystallized and stress relieved.

(4) Atomization: The ultrasonic vibration plate was placed at a depth of 3.0 cm below the liquid surface, and the temperature of the solution was maintained at 30 ° C, and an ultrasonic atomization frequency of 1.65 MHz was supplied to the carbon nanotube solution. The atomization rate of 25~30ml/hr can be achieved, and the atomized particle has a particle size of about 3μm. The carrier gas is fed into the gas pipe connected to the container containing the MWNT solution, and the flow rate of the carrier gas is 22L/ Min.

(5) spin coating: the carrier gas guides the atomized particles onto a susceptor of a spin coater, and the substrate sheet placed on the susceptor has been coated with the first cladding layer and The susceptor rotates synchronously, and the atomized particles are coated on the first cladding layer to form a conductive film combined with the first cladding layer.

Referring to Fig. 4, when the spin coating of the ultrasonic atomized particles is performed, the pretreatment by one wet spin coating and one preliminary film spin coating is repeated, and the recoating spin coating is repeated at least once. Among them, the rotational speed of the wet spin coating is 300r.pm and 450r.pm alternately, and the rotational speed of the preliminary film spin coating is increased from 450r.pm to 6000r.pm, and then enters again. Film formation spin coating. During the coating process, the susceptor is continuously rotated in a staged cycle as shown in FIG. 4, and the interval (I) represents the change in the rotational speed of the wet spin coating, and the interval (II) represents the preliminary film forming spin coating. The stepwise rotation speed change, the interval (III) is a stepwise rotation speed change of the re-filming rotary coating, thereby enabling the atomized particles to be uniformly applied to the surface of the first cladding layer, and The film thickness of the conductive film is controlled by the length of time of spin coating. In Figure 4, the different stages are represented by different letters, and the speed and time represented by them are organized as shown in Table 1. The time of each stage in Table 1 should not be limited, and can be adjusted according to actual needs.

The spin coating time is controlled from 10 minutes to 60 minutes to control the spin coating time to achieve the design of the multilayered wall carbon nanotube conductive film, which is mainly by adjusting c~ The time of f is used to adjust the thickness of the conductive film.

(6) Hot pressing: the temperature of the upper and lower stampers of a hot press is raised to 70 ° C, and the temperature is maintained for 1 hour, and the temperature fluctuation is controlled within ±0.25 ° C, and four pieces of 5 cm × 5 cm PET sheets are cut. And rinsing the PET sheets in a cleaning sequence of deionized water, ethanol, deionized water, acetone, deionized water, respectively, and clamping the first coating layer and the conductive layer in the manner of the above two pieces. The substrate sheet of the film was placed on top of the PET sheet by a stainless steel jig of 10 cm × 10 cm, placed between the upper and lower stampers of the hot press, and subjected to a pressure of 100 kg/cm ² for 30 minutes.

(7) Cleaning: The hot-pressed substrate sheet is cleaned in the manner described in the foregoing step 107, and a finished product of the excellent flexible carbon nanotube conductive film incorporating the first coating layer can be obtained.

Referring to FIG. 6 , a scanning electron microscope photograph is taken to illustrate that the first cladding layer is made of PVA, and the first cladding layer is used as a base, and the carbon nanotubes are coated thereon to form A microscopic enlarged view of the finished flexible film of the carbon nanotubes, which are respectively combined with the first cladding layer.

To produce the finished carbon nanotube conductive film as shown in the second preferred embodiment, the second coating is formed on the conductive film as described in the foregoing step 307 after (7) cleaning. After the layer is pressed and (6) is hot pressed to form the second cladding layer, the finished carbon nanotube conductive film of the PVA package can be prepared, as shown in FIG. A microscopic enlarged view of the finished conductive film formed by forming a first cladding layer, a carbon nanotube conductive film and a second cladding layer on the sheet, and showing the carbon nanotubes and the first and the first In the case where the two cladding layers are combined and partially protected by the second coating layer, the image of the carbon nanotube of FIG. 7 is obtained by forming the second coating layer on the carbon nanotube conductive film. Compared with Figure 6, it is relatively ambiguous.

<Flexibility test>

Referring to Fig. 5, the prepared substrate sheet in which the first cladding layer and the conductive film were bonded was cut into a test piece 41 of 1 cm × 2 cm, and the conductivity of the test piece 41 before being bent was measured. Next, the two opposite sides of the longer side of the test piece 41 are respectively fixed to a fixed holder 42 and a movable holder 43 spaced apart from the fixed holder 41, and the movable holder 43 is fixed toward the fixed holder 43 The holder 41 is displaced to the opposite side of the long side of the test piece 41 by a distance of 1 cm, and further displaced until the distance between the opposite sides of the long side of the test piece 41 is 0.5 cm, and the test piece 41 follows the activity. The movable seat 43 is flexed and bent, and the movable clamp 43 is displaced away from the fixed clamp 42 to return the test piece 41 to a flat state, and the bent piece of the test piece 41 is measured. The electric resistance repeats the above-described operation of bending the test piece 41, and the test piece 41 is again measured for the sheet resistance after returning to the straight state. The change in conductivity can be correspondingly reflected by the change in sheet resistance, and the more stable the sheet resistance value, the more stable the conductivity is.

The test results show that the sheet resistance of the test piece 41 is increased by 5% after the bending of 100 times, and the sheet resistance of the test piece 41 is increased by 10% after the bending of the test piece 41, and the sheet of the test piece 41 is bent 500 times. The resistance rises by 10%. Further, the step (3) in the above <Specific Example> is omitted, and a substrate sheet which is not coated with the first coating layer and has only the conductive film is prepared as a control group, and is cut into the test piece 41 as described above. With the same size, the conductivity of the conductive film substrate sheet of the control group was tested in the same manner after repeated bending, and the results showed that after 100 times of bending, the sheet resistance increased by 10%. After 250 times, the sheet resistance increased by 20%, and after 500 bends, the sheet resistance increased by 20%.

Among them, the test piece not containing the first coating layer of the PVA material is represented by CNT/PET, and the test piece containing the first coating layer is represented by PVA/CNT/PET, and the original piece before the flexural test is not performed. The electric resistance was: CNT/PET ≒ 100 Ω/□ (where □=cm ² , that is, Ω/□=Ω/cm ² ), and PVA/CNT/PET ≒ 150 Ω/□. Due to the previous several twists, the sheet resistance of CNT/PET and PVA/CNT/PET are unstable, which cannot be clearly compared. Therefore, CNT/PET and PVA/CNT/PET are separately used. After the test piece was bent 50 times to stabilize the sheet resistance (conductivity), it was officially entered into the flexural resistance test. The sheet resistance values after stabilization for 50 times were CNT/PET ≒ 3 K Ω / □ and PVA / CNT / PET ≒ 360 Ω / □, respectively.

(The number of flexings in the table below does not include the number of times of pre-bending 50 times.)

From the above results, it can be explained that the test piece coated with the PVA first coating layer can effectively reduce the rise ratio of the sheet resistance compared with the uncoated PVA layer, and can effectively reduce the decrease ratio of the conductivity. The flexural flexibility of the prepared conductive film is improved and has a relatively stable reliability.

<Light transmittance at 550 nm wavelength light>

Since the original light transmittance of PVA is as high as 95%/cm or more, if no bubbles and cracks are generated, when the thickness is 1 μm or less, the light transmittance may be higher than 99.9%, so the light transmittance of the conductive film is coated by PVA. There is no significant impact on the rate. The measurement result also shows that the substrate sheet combined with the first cladding layer and the conductive film has a light transmittance of 90% at 550 mm, and the substrate with the first and second cladding layers and the conductive film is bonded. The sheet has a light transmittance of 89% at 550 mm, which is compared with the light transmittance specification of 550 nm of 70% to 90% of the conductive film currently used in the industry, and shows the carbon nanotube conductive film produced by the manufacturing method of the present invention. Has value for practical use.

In summary, the method for producing a carbon nanotube conductive film having excellent flexibility of the present invention can attain the following effects and advantages, and thus achieve the object of the present invention:

1. The first cladding layer 30 of the flexible material is combined with the multi-layered wall carbon nanotubes, or the first cladding layer 30 of the flexible material is combined with the multi-layered wall carbon nanotubes The second coating layer enables the finished flexible conductive film to be finished, and the carbon nanotubes which pass through the conductive film exhibit excellent optical material properties such as light transmittance and conductivity, and can also be matched. The first cladding layer 30, or the first and second cladding layers, form a stronger structure and can exhibit better flexibility, so that the manufacturing method of the present invention can produce nano carbon with excellent flexibility. The conductive film is used to enhance the reliability and durability of related applications.

2. The carbon nanotube conductive film produced by the manufacturing method of the present invention has a transmittance and resistance value of light at a wavelength of 550 nm which still conforms to the specifications of a general conductive film, and indeed has practical value in commercial applications.

Third, by using the manufacturing method of the present invention, it is possible to produce a multilayer flexible carbon nanotube having a relatively low cost as a raw material, and to have excellent flexibility in a relatively easy process with respect to equipment which is relatively easy to obtain with respect to existing manufacturing techniques. The carbon nanotube conductive film product has the advantage of reducing the manufacturing cost.

The above is only the preferred embodiment of the present invention, and the scope of the invention is not limited thereto, that is, the simple equivalent changes and modifications made by the scope of the invention and the description of the invention are All remain within the scope of the invention patent.

20. . . Nano carbon tube solution

twenty one. . . Substrate sheet

twenty two. . . Pedestal

twenty three. . . Atomized particle

twenty four. . . Carrying gas

25. . . Atomizing container

26. . . siphon

27. . . Ultrasonic component

28. . . Liquid container

29. . . Lifting seat

30. . . First coating

41. . . Audition

42. . . Fixed clamp

43. . . Activity holder

1 is a flow chart showing a first preferred embodiment of a method for manufacturing a carbon nanotube conductive film having excellent flexibility according to the present invention;

2 is a flow chart showing a second preferred embodiment of a method for manufacturing a carbon nanotube conductive film having excellent flexibility according to the present invention;

Figure 3 is a schematic view showing the combination of the devices used in the first and second preferred embodiments;

Figure 4 is a schematic view showing the change of the rotational speed set at different times during the spin coating of the first and second preferred embodiments;

Figure 5 is a schematic view showing the process of conducting a flexural test on a conductive film test piece produced by the manufacturing method of the present invention;

Figure 6 is a scanning electron microscope photograph showing the case where the carbon nanotubes of the conductive film are bonded to the first cladding layer;

Fig. 7 is a scanning electron microscope photograph showing the case where the carbon nanotubes of the electroconductive thin film are combined with the first and second cladding layers.

Claims (30)

A method for manufacturing a carbon nanotube conductive film with excellent flexibility, comprising the steps of: (i) preparing a carbon nanotube solution, and adding a predetermined amount of carbon nanotube components to a predetermined amount of solvent. a carbon nanotube solution having a viscosity value of 1 to 50 c.p, and the carbon nanotube component has a plurality of multi-layered wall carbon nanotubes; (ii) a transparent flexible material coating to make a transparent The flexible material is applied to a substrate sheet placed on a base, and the flexible material is formed on the substrate sheet by rotating the base to form a first coating layer; (iii) atomizing, Applying an ultrasonic atomization frequency to the carbon nanotube solution, atomizing the carbon nanotube solution into a plurality of atomized particles dispersed and carrying the carbon nanotubes, and providing a carrier gas to enable the The atomized particles are transported along a predetermined path, wherein the atomized particles have a particle diameter of from 0.5 μm to 50 μm; and (iv) spin coating, the atomized particles are guided to have been coated with the first Above the pedestal of the coating layer, the atomized particles are evenly coated on the first coating layer by rotating the pedestal. Forming a conductive thin film in combination with the first cladding layer. The method for producing an excellent flexible carbon nanotube conductive film according to claim 1, wherein in the step (i), the solvent is a liquid selected from the group consisting of water, Ethanol, isopropanol and acetone. The method for producing an excellent flexible carbon nanotube conductive film according to claim 2, wherein in the step (ii), the first cladding layer is selected from the group consisting of Made of flexible material: polyvinyl alcohol, polyacrylic acid, polyethylene glycol, polymethyl methacrylate, and polycarbonate. The method for producing an excellent flexible carbon nanotube conductive film according to claim 3, wherein the flexible material for forming the first coating layer is polyvinyl alcohol. The method for producing an excellent flexible carbon nanotube conductive film according to claim 3, further comprising a step (a) after the step (iv), wherein the step (a) is hot pressing, Applying a predetermined pressure to the substrate containing the conductive film and the first cladding layer at a predetermined temperature for compacting and compacting the conductive film, and pressing the carbon nanotubes into the first The coating layer forms a tight bond with the first coating layer. The method for producing an excellent flexible carbon nanotube conductive film according to claim 5, wherein in the step (a), the temperature is applied at a temperature of 50 ° C to 110 ° C of 1 to 200 kg / cm. The pressure of ² is hot pressed for 30 seconds to 30 minutes. The method for producing an excellent flexible carbon nanotube conductive film according to claim 6, wherein in the step (a), the pressure is applied at a temperature of 90 ° C at a pressure of 100 kg/cm ² . Press for 10 minutes. The method for manufacturing an excellent flexible carbon nanotube conductive film according to claim 3, further comprising a step (b) after the step (iv), wherein the step (b) is forming a second In the coating layer, a transparent flexible material is coated on the conductive film to form the second coating layer. The method for producing an excellent flexible carbon nanotube conductive film according to claim 8, wherein in the step (b), the second coating layer is selected from the group consisting of Made of flexible material: polyvinyl alcohol, polyacrylic acid, polyethylene glycol, polymethyl methacrylate, and polycarbonate. The method for producing an excellent flexible carbon nanotube conductive film according to claim 9, wherein in the step (b), the flexible material of the second coating layer is a poly Vinyl alcohol. The method for manufacturing an excellent flexible carbon nanotube conductive film according to claim 9 further comprising a step (c) after the step (b), wherein the step (c) is hot pressing, Applying a predetermined pressure to the substrate containing the conductive film, the first cladding layer and the second cladding layer at a predetermined temperature for compacting and compacting the conductive film, and making the first and second The coating layer is pressed against the conductive film to form a tight bond between the carbon nanotubes and the first and second coating layers. The method for producing an excellent flexible carbon nanotube conductive film according to claim 11, wherein in the step (c), 75 to 125 kg/cm ² is applied at a temperature of 60 to 90 ° C. The pressure is hot pressed for 30 minutes. The method for producing an excellent flexible carbon nanotube conductive film according to claim 12, wherein in the step (c), the pressure is substantially 100 kg/cm ² at a temperature of 90 ° C. Hot pressing was carried out for 10 minutes. The method for producing an excellent flexible carbon nanotube conductive film according to claim 12, wherein in the step (i), the carbon nanotube solution further has a predetermined amount of a surfactant. The component, and the surfactant component is used to prevent aggregation of the multi-walled nanotubes in the carbon nanotube component. The method for producing an excellent flexible carbon nanotube conductive film according to claim 14, wherein the surfactant component is a substance selected from the group consisting of sulfate esters of alcohols. An alkyl sulfonate, an alpha olefin sulfonate, a fourth ammonium salt, an ethylene oxide system, a polyoxyethylene alkyl ether, and combinations thereof. The method for producing an excellent flexible carbon nanotube conductive film according to claim 15, wherein the surfactant component is a substance selected from the group consisting of C ₄ ~ C ₁₈ of the linear alkyl sulfonate, potassium linear alkyl sulfonate of C ₄ ~ C ₁₈ straight-chain alkyl sulfate of C ₄ ~ C ₁₈ straight-chain alkyl sulfate of C ₄ ~ C _18, C ₄ ~ C ₁₈ linear sodium alkylbenzene sulfonate, C ₄ ~ C ₁₈ linear alkyl benzene sulfonate, C ₄ ~ C ₁₈ linear alkyl sodium benzene sulfate, C ₄ ~ C ₁₈ linear alkylbenzene sulfate, C ₂ ~ C ₁₆ straight-chain alkyl group of quaternary ammonium salts, alpha] -olefin sulfonates, polyoxyethylene alkyl is a C ₂ ~ C ₁₆ alkyl ethers of, and etc. combination. The method for producing an excellent flexible carbon nanotube conductive film according to claim 16, wherein the surfactant component is selected from sodium dodecyl sulfate. The method for producing an excellent flexible carbon nanotube conductive film according to claim 16, wherein in the step (iii), the ultrasonic atomization frequency is 20 kHz to 2.45 MHz. The method for producing an excellent flexible carbon nanotube conductive film according to claim 18, wherein in the step (iii), the ultrasonic atomization frequency is 1.65 MHz. The method for producing a highly flexible carbon nanotube conductive film according to claim 18, wherein in the step (iii), the atomized particles have a particle diameter of 2 μm to 7 μm. The method for producing an excellent flexible carbon nanotube conductive film according to claim 20, wherein in the step (iii), the atomized particles have a particle diameter of substantially 3 μm. The method for producing an excellent flexible carbon nanotube conductive film according to claim 21, wherein in the step (iii), when the spin coating is performed, the susceptor is first wet-rotated. Coating and pre-processed spin coating pretreatment, and then performing at least one re-film spin coating, in the re-film spin coating, sequentially through a low speed, a medium speed and a high speed The cycle is rotated, and the ratio of the low speed, medium speed and high speed speed is 2~3:3~6:8~40. According to the manufacturing method of the excellent flexible carbon nanotube conductive film according to claim 22, in the step (iii), the low-speed rotation speed is 300 to 450 r. pm, and the medium-speed rotation speed is 450~900r.pm, and the high speed is 1200~6000r.pm. The method for producing an excellent flexible carbon nanotube conductive film according to claim 23, wherein in the step (iii), the rotational rotation of the wet spin coating is 300 r.pm and 450 r.pm. Several times, the number of revolutions of the preliminary film spin coating was increased from 450 r.pm to 6000 r.pm, and then re-filming was applied. The method for producing an excellent flexible carbon nanotube conductive film according to claim 24, wherein in the step (i), the carbon nanotube solution has 1 part by weight of a surfactant group. Parts, 1 part by weight of the carbon nanotube component, and 1000 to 1,000,000 parts by weight of a solvent. The method for manufacturing an excellent flexible carbon nanotube conductive film according to claim 25, further comprising a step (d) between the step (iv) and the step (b), the step (d) It is a cleaning to remove the surfactant remaining in the conductive film. The method for producing an excellent flexible carbon nanotube conductive film according to claim 26, wherein in the step (d), the substrate having the conductive film is first placed in deionized water. Rinse for 5 to 30 minutes, and soak for 2 hours for water change, repeat 5 times, then soak the ethanol for 2 hours, and then vacuum at temperature 60 ° C for 12 hours. The method for producing an excellent flexible carbon nanotube conductive film according to claim 27, wherein in the step (iii), the flow rate of the carrier gas is from 1 L/min to 200 L/min. The method for producing an excellent flexible carbon nanotube conductive film according to claim 28, wherein in the step (iii), the flow rate of the carrier gas is substantially 22 L/min. The method for producing an excellent flexible carbon nanotube conductive film according to claim 28, further comprising a step (e) before the step (i), wherein the step (e) is a purification of the multilayer wall The carbon nanotubes are respectively subjected to acid washing with a high concentration hydrochloric acid solution, water washing by a precipitation method, and vacuum drying to purify the multi-walled carbon nanotubes.