KR100626090B1 - Valve type electrospray apparatus for preparing materials having nano-structure - Google Patents

Abstract

The present invention relates to an electrospray system for manufacturing nanostructures, comprising a shaft inside a cylinder of an electrospray to block the flow of a solution during the process, and at least one capillary tube for the stable and bulk spraying of the solution A multi-nozzle consisting of tubular needles is adopted, and has a valve type electrostatic spraying mechanism part having an inlet for supplying a solution and an air inlet for driving a shaft; A high voltage generator for imparting charge to the solution so that the injection solution can be atomized or refined; A precise feed control supply unit for quantitatively feeding and supplying a small solution; Disclosed is a valve type electrostatic spraying system including a pneumatic control unit for driving a shaft; an integrated unit for inducing spray fine particles to an object.

Electrostatic spraying, valve type electrostatic spraying, multi-nozzle, nano structure

Description

Valve type electrospray apparatus for preparing materials having nano-structure}

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a perspective view schematically showing the configuration of a valve type electrostatic spraying mechanism part including a multiple nozzle composed of a capillary tube type needle according to the present invention.

Figure 2 is a side view schematically showing the configuration of the electrostatic spray system of the present invention including a blade-type induction collector.

Figure 3 is a SEM photograph of the nano-grade microfibers prepared from the apparatus of the present invention

<Description of Main Reference Signs in Drawing>

11 Electrostatic sprayer cylinder cap 11a ... Air inlet 12 ... Cylinder body

13 Guide pin 14 ... Piston 15 ... Piston spring

16.Solution blocking shaft 17 ... Betach 17a ... Solution inlet

18.Solution chamber .. 19 .... High voltage application connection 20..Solution chamber cap

21.Multiple nozzles 22, 22a ... Capillary tube needle 31.Pneumatic control part

32.Electrostatic spraying mechanism part 33.Quantity feeding control part 34.

35 Multi-nozzle section 36 Winder 37 Unwinder

38 ... blade type induction collector section

The present invention relates to a valve type electrostatic spray device capable of producing organic and inorganic nanostructures. The present invention also relates to an electrospray system capable of spraying a large area on an object to be continuously transported.

In general, electrostatic spraying method is applied to powder coating, solvent and water-based coating, oil ring coating process because it can increase the adhesion efficiency of atomized particles to the workpiece by reducing the consumption by applying a charge to the particles by applying a high voltage.

In the conventional electrostatic spraying machine, a disk-type or bell-type electrostatic atomizing device atomized by high-speed rotational force (10,000-70,000 rpm) is suitable for mass coating and is widely used industrially. In addition, in powder coating, an electrostatic spray gun is used in which a needle electrode is installed at the center of the nozzle to apply a high voltage of 30kv or more, and an ionization zone is formed between the nozzle and the workpiece together with corona discharge.

However, the conventional electrostatic spraying method is difficult to spray a high viscosity solution such as a polymer solution because it is atomized by the rotational centrifugal force or air pressure. In addition, at the same time, it is difficult to produce fine particles having a small particle size of 10 μm or less because of atomizing and spraying a large amount, and there is a limitation in thinning the coating film.

Recently, with the emergence of nanotechnology, electrostatic spray technology is used to manufacture various structures such as nano-thick organic or inorganic fibers, porous membranes, and functional coatings.

For example, in order to improve biofunction, calcium phosphate (CaP) ceramic coatings on titanium implants ("Electrostatic spray deposition (ESD) of calcium phosphate coatings, an in vitro study with osteoblast-like cells" by MC Siebers, XFWalboomers , SCG Leeuwenburgh, JGC Wolke, and JA Jansen, Biomaterials 25 (2004) , 2019-2017], "Thin films of lithium manganese oxide spinel as cathode materials for secondary lithium batteries" by JL Shui et al. Electrochimica Acta 49 (2004) 2209-2213], TiO2 film coating ["Deposition mechanism and structural characterization of TiO ₂ films produced using ESAVD method" by Xianghui Hou and Kwang-Leong Choy, Surface and Coatings Technology , 180-181 (2004) , 15-19], TiO2 fibers ["Electrospun mesoporous titanium dioxide fibers" by Sudha Madhugiri, Bo Sun, Panagiotis G. Smirniotis, John P. Ferraris and Kenneth J. Balkus, Jr., Microporous and Mesoporous Materials, 69 (2004) , 77-83], Nano-Weighted Organic Fibers and Nanocomposites ["A review on polymer nanofibers by electrospinning and their applications in nanocomposites" by Zheng-Ming Huang, Y.-Z. Zhang, M. Kotaki and S. Ramakrishna, Composites Science and Technology, 63 (2003) , 2223-2253.

However, the electrostatic spraying method introduced in the above document is limited to industrial application since it only describes the basic device configuration.

On the other hand, U.S. Patent No. 4,323,525 discloses a method for producing a tubular article through the electrospinning method. However, since only one injection nozzle is constructed per syringe, it is not suitable for mass production.

As it is well known, a small amount of solution has to be injected from the nozzle in order to produce a nano-class object, so when the number of nozzles is small, there is a problem in coating a large area continuously. In addition, since electrostatic spraying uses high voltages of thousands to tens of thousands of volts, a kinematic means for controlling the solution is required when problems such as nozzle clogging or uneven spraying occur during the spraying process.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and the object of the present invention is to provide a valve type electrostatic spraying device which employs a spray nozzle composed of multiple capillary tube needles and controls the flow of a solution during a process. .

It is another object of the present invention to provide an electrostatic spraying system in which an induction collector is installed such that spray fine particles are uniformly sprayed to a target area of a large area continuously transported.

Valve type electrostatic spraying device according to the present invention to achieve the above object, the fluid inlet for supplying a solution; A shaft portion for controlling and blocking the flow of the solution transferred to the nozzle portion during the process; A diaphragm portion for preventing a solution inside the cylinder from being transferred to a portion other than the nozzle; An air inlet for operating the shaft downward; A high voltage application connection for charging the solution; It comprises a; multi-nozzle portion consisting of at least one capillary tube-shaped needle for the stable spray atomization or refinement of the solution.

In addition, the present invention includes a high voltage generator device for imparting charge to the solution so that the injection solution can be atomized or refined, including the mechanism of the valve-type electrostatic spray described above; A precise feed control supply unit for quantitatively feeding and supplying a small amount of solution; It is provided with an electrostatic spraying system including a pneumatic control unit for driving the shaft; an integrated unit for the induction of the atomized particles to the object.

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

First, Figure 1 is a cross-sectional view schematically showing the configuration of the valve type electrostatic spraying mechanism having a multi-nozzle of the present invention.

The valve-type electrostatic spraying device of the present invention includes a shaft 16 installed to operate up and down to block the flow of the solution; A cylinder cap 11 having an air inlet 11a for driving a shaft; Cylinder body 12; A guide pin 13 installed so that the central axis of the shaft is kept constant without deviation; A piston 14 integrally configured such that the shaft is driven up and down by the action of spring tension or pneumatic pressure; A piston spring 15 acting to recover the piston and shaft driven by external air pressure; A diaphragm portion 17 for preventing a solution inside the cylinder from flowing into a portion other than the nozzle; A solution chamber 18 which is a solution retention chamber having an inlet port 17a of the solution; An energizing connector 19 for applying charge to the solution by applying a high voltage; A chamber cap 20 installed between the solution chamber and the injection nozzle and having an opening to block flow of the solution by the operation of the shaft; It consists of a spray nozzle part 21 having a multi-needle 22 composed of at least one capillary tubular needle to enable mass spraying of the solution and stable spraying.

The electrostatic spray mechanism is operated by the following principle.

When the solution is supplied to the inlet 17a, the diaphragm 17 and the shaft 16 are lifted to the upper side while the tension of the spring 15 is overcome by the pressure of the solution, and the opening of the chamber cap 20 is opened. The feed solution in the chamber 18 is transferred to the nozzle unit 21 while being made. At this time, the shaft has a needle-shaped end to completely close the opening of the chamber cap 20 provided between the solution chamber portion 18 and the nozzle portion 21 to completely block the flow of the solution.

If a problem occurs during the process, the shaft end is driven downward to block the flow of the solution while the needle end of the shaft blocks the opening of the chamber cap. At this time, the driving of the shaft is made by the external air pressure 11a according to the operation of the pneumatic valve. The shaft is driven by the external air pressure which is greater than the spring tension, thereby blocking the opening of the chamber cap.

Although not shown as shown in Figure 1, the end of the shaft can be configured in a bundle if the opening of the chamber cap is large to transfer a large amount of solution.

The driving method of the shaft is configured to block the opening of the chamber cap while the shaft moves from top to bottom by external pneumatic action.

As another method of blocking the opening of the chamber cap, there is also a method in which the end of the bundle of the bunched shaft is positioned under the chamber cap to drive it from the bottom to the top. At this time, since the spring exerts a force to operate the shaft to the top, the bundle end located at the bottom of the chamber cap closes the opening of the chamber cap at the bottom. The transfer of the solution is carried out by opening the chamber cap opening by moving the agglomerated shaft which blocked the lower portion of the chamber cap by external pneumatic pressure. This method has the advantage of improving the cutting property of the solution at the tip (22) of the spray nozzle.

The diaphragm 17 provided in order to prevent leakage to the other part of a nozzle part maintains airtightness by the fluorine-type diaphragm system like Teflon. If the shaft diameter is small, a packing material such as Teflon is inserted into the shaft to maintain airtightness.

Charge to the solution is applied directly to the solution by inserting a conducting rod when using a non-conductive chamber. In the case of a metal chamber, the energizing connecting portion 19 is applied to the chamber. Since the energized connection portion uses a high voltage, it is preferable to be connected in a removable manner by pneumatic.

The voltage applied to the solution is 0.5kV to 100kV. Preferred applied voltage is 3kV to 60kV.

The solution transferred through the chamber cap is transferred to the nozzle unit 21 and discharged through the needles 22 and 22a. At this time, in order to manufacture a nano-class structure, the discharge amount per needle is preferably 0.2 to 50 µl / min.

The electrostatic spray nozzle consists of multiple needles in which the capillary tube-shaped needles 22 are arranged in a circle at least five or more. Three-row rectangular arrays are also possible. At this time, the diameter of the capillary tube is preferably 0.01 to 0.2 mm in inner diameter and 0.03 to 2 mm in outer diameter, and the length L is preferably 0.5 to 50 mm. More preferable inner diameter is 0.02-0.2 mm, and length is 10-40 mm. The shape of the capillary tube preferably has a flat or obliquely inclined shape with a rounded tip. The material of the capillary tube generally uses a metal, but if the inner diameter of the tube is 0.1 mm or less, it is preferable to use silica or ruby.

In order to spray a large area of the object to be transported, the spray nozzles, which consist of capillary tubular multi-needles, may be arranged in a single column in a row. At this time, the spray nozzle is composed of 1 to 50 rows. Preferably it consists of 1-20 rows. The distance between the spray nozzles is 2 to 30 mm. Preferable spacing is 2 to 10 mm.

The material of the chamber, the chamber cap, and the nozzle body in the mechanism part is acetal, polypropylene [poly (propylene); PP], polyethylene [poly (ethylene); PE], polytetrafluoroethylene (PTFE) fluorine-based polymer It is preferable to use engineering plastics having chemical resistance, such as poly (etheretherketon); PEEK, and polyamide [(poly) amide] polymer.

Figure 2 is a side view schematically showing the configuration of the electrostatic spray system of the present invention including an induction collector.

Although not shown, the solution of the solution storage part is quantitatively supplied to the electrostatic spraying mechanism part 32 by the metering feeder 33. The quantitative supply of the solution is done by a precision gear pump driven by a micro-stepping motor employing a microprocessor control method, by a gear pump driven by an AC or DC geared motor, or the solution stored in a small syringe is stored in a precision syringe pump. Precisely. At this time, the amount of the solution to be supplied is dependent on the number of spray needles.

The drive motors for driving the gear pump are insulated from each other by using an adapter of non-insulating material between the gear pump and the drive motor because the solution is energized at high voltage from hundreds to tens of thousands of volts.

The solution quantitatively supplied to the injection mechanism 32 may be blocked by the driving of the shaft included in the cylinder as needed during the process. At this time, the shaft drive is made by the injection air control unit 31. Inlet air is supplied from an air compressor, and its shut off supply control is made by operation of a pneumatic valve.

The solution in the cylinder chamber 18 is applied by an energization line connected from the high voltage generator 34 to have charge. At this time, the voltage strength of the DC power supply (DC) is preferably 0.5kV ~ 100kV.

The charge-containing solution is discharged through the nozzle through the multi-nozzle, and the discharged charge solution is atomized or refined by electrostatic repulsion.

When a large number of nozzles are required for mass spray coating the large-area object 39 continuously moving the atomized particles, the multiple nozzles 35 are arranged in rows, or one pack. It can consist of several packs of columns. At this time, the arrangement interval of the multiple nozzles configured in one pack depends on the strength of the applied voltage and the state of the solution. Spray pack spacing is 5 to 200 mm. Preferred spacing is 20 to 150 mm. Spray pack can be sprayed while reciprocating left and right for uniform coating on the object.

Although not shown in FIG. 2, when using a spray nozzle composed of multiple needles or a nozzle pack composed of a plurality of needles to guide the fine spray particles to a predetermined region, it is preferable to install the guide plate so that the spray particles do not deviate from both ends. .

The electrostatic spraying device of the fine particles depends on the state of the material of the object to be supplied and conveyed from the supply unit 37. The accumulation target material 39 of the chargeable liquid may be a nonwoven fabric, a film, paper, a fabric, a thin plastic sheet, or a glass sheet. Since these objects are non-metallic, it is preferable to carry out the pretreatment and conveying so that a fine particle may not bounce off an injection surface by the solution or the conductive solution, or the corona treatment which have the opposite polarity to the charging solution. In particular, sheets, films, and plastic materials without pores are transferred by conducting fluid or corona pretreatment.

When the object to be transported 39 is a large area having a porous structure such as nonwoven fabric, paper, web, and fabric, an induction integrated part 38 is installed at the bottom to induce electrosprayed fine particles as shown in FIG. do. In this case, the inductive integrated part may be grounded to have a polarity opposite to that of the charged particles, or may be applied with a voltage having a different polarity.

It is preferable that the shape of the induction integrated portion be sharply formed in a blade shape in order to increase the degree of integration of charged fine particles. As an alternative, the object may be sprayed directly onto the grounded roll.

As a material of the integrated portion, a metal plate having excellent conductivity is preferably used, and various kinds of conductive materials may be employed.

The blade-like integrated portion may be arranged in rows according to the speed of the object to be transferred.

The object in which the spray particles are accumulated is wound in the winding unit 36 after passing through a drying apparatus such as a UV dryer.

The sprayable solution using the valve type electrostatic spraying system of the present invention can vary from low viscosity sol to high viscosity polymer solution. In particular, sol containing TiO2, sol containing silver particles, polymer solution of PVDF [poly (vinylidenefluoride)] / dimethylacetamide (DMAc) / acetone, PAN [poly (acrylonitrile)] / solvent [DMF (dimethyl) -formamide), DMAc (dimethylacetamide), DMSO (dimethylsulfoxide) polymer solution, polyimide / DMAc polymer solution, poly (lactic acid) polymer, protein polymer solution, calcium phosphate solution, YSZ solution, alumina solution , Silica solution, pigment, dye solution, ink solution, ITO (indium tin oxide) sol, conductive polymer solution, organic-inorganic mixed polymer solution. At this time, the sol containing a less volatile solvent with less surface tension is easier to refine.

The fine particles produced from such a solution have organic-inorganic fine particles having a diameter of 100 to 5000 nm and a fibrous form. In addition, a porous organic-inorganic membrane having a pore size of 0.1 to 5 µm and a thickness of 0.05 to 10 µm could be prepared.

FIG. 3 shows electrostatic spraying from a solution in which 12 wt% of polyvinylidene fluoride (PVDF) is dissolved in a mixed solvent of acetone and dimethylacetamide (DMAc) with a weight ratio of 7: 3 using the valve type electrostatic spraying device of the present invention. It shows a SEM picture of the microfibers having a nanostructure prepared by. At this time, the number of needles arranged in a circle in the nozzle was 10, the inner diameter of the capillary tube-shaped needle was 0.1mm, the length was 6mm, the applied voltage intensity was 20kV.

According to the present invention, a valve-type electrostatic spraying mechanism having a multi-nozzle having a shaft capable of controlling the flow of the chargeable liquid during the process, and having at least several capillary tube-type needles ranging from low viscosity sol to high viscosity polymer solution It is effective in stably producing a large amount of atomizing or micronized particles.

In addition, the grounded blade-type induction collector is installed in the lower portion of the object to be transported, there is an effect that the electrostatic particles are uniformly sprayed on the large area of the object.

The valve type electrostatic spraying system of the present invention having such an advantage can be very useful for producing a porous membrane coating and a porous organic / inorganic membrane including nano-grade inorganic particles and microfibers.

Claims (4)

A solution inlet for supplying a solution; A shaft portion for controlling and blocking the flow of the solution transferred to the nozzle portion; Air inlets and springs for actuating the shaft; High voltage application connections for imparting charge to the solution; In the electrostatic spraying mechanism including the nozzle portion, when the solution is supplied to the solution inlet (17a), the tension of the spring 15 is overcome by the pressure of the solution to lift the shaft 16 to the top while the solution chamber 18 Opening of the chamber cap 20 provided between the nozzle and the injection nozzle 21 is opened, and the solution in the solution chamber 18 is transferred to the nozzle part 21, and if a problem occurs during the process, the tension of the spring 15 is greater than the tension of the spring 15. The shaft 16 is driven downward by the external air pressure 11a to block the opening of the chamber cap 20 to block the flow of the solution. Valve type electrostatic spraying mechanism according to Figure 1, characterized in that at least one capillary tube-shaped needle 22 is configured to be. The spray nozzle according to claim 1, wherein a capillary tube needle having a diameter of 0.01 to 1 mm, an outer diameter of 0.02 to 2 mm, and a length of 0.5 to 50 mm is multiplied at least several times in one nozzle in a circular or square shape. The electrostatic spraying device according to claim 1, wherein the voltage applied to the electrostatic spraying machine is 0.5 kV to 100 kV, and the discharge amount per needle is 0.2 to 50 µl / min. A valve type electrostatic spraying mechanism unit characterized in that the nozzle is composed of a multi-needle of claim 1 arranged in at least one row in one pack; High-voltage generator device for applying charge to the solution; A precise feed control supply unit for quantitatively feeding and supplying a small amount of solution; Pneumatic control unit for driving the shaft; Electrostatic spray system comprising; blade-type integrated unit installed in the lower portion of the transport object for the induction of spray fine particles to the object

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