DE112006003400T5 - Apparatus and method for electrostatic spraying - Google Patents

Abstract

Device for electrostatic spraying with:
a plurality of spinning units, each of which has a plurality of nozzles arranged two-dimensionally to electrostatically spray a polymer solution containing a polymeric substance formed using a solvent as a liquid; and a first collector, the like is disposed opposite to the plurality of nozzles with an insulating layer therebetween, the polarity of the voltage applied to the first collector being different from the polarity of the voltage supplied to the nozzles, or the first collector grounded to ground potential,
a first voltage source for applying a predetermined high voltage to the nozzles, and
a collector section which is associated with the spinning units and which holds a collector track movable,
wherein the spinning unit is provided with a means for forming an air flow flowing in a direction substantially orthogonal to the direction of spray from the nozzles to the ...

Description

Technical area

The The present invention relates to a device for electrostatic Spraying and an electrostatic spraying process for electrostatically spraying a solution that contains a polymeric substance.

Technical background

The electrostatic spraying (electrospinning) is as below described executed; a polymeric substance known as the material is to be used as a coating, is mixed with a solvent to form a solution manufacture; the solution is in a container with a pointed end such as the needle point a syringe or a thin glass tube, and there will be a high voltage between the container and an object applied to which to spray the polymeric substance is. In the electrostatic spraying process, the polymeric Substance in the container is charged to charged charges polymeric substance is due to acting between the charges Repulsive forces in sprayed form from the tank top to the side, acting as a collector is designated and has a polarity that is different is that of the spray side (the side of the tip of the Container), or issued to the ground side, the Coulomb forces are used, and then on the collector side collected and laminated. The electrostatic Coating is a technique involving an electrostatic spray process is applied, and it is well known that the electrostatic Coating applied to vehicle bodies such as automobile bodies becomes. Electrostatic coating is not on the coating limited by vehicle bodies, but can be used for coating different types of products are applied. The present The invention relates to a device especially for electrostatic spraying an artificial polymeric substance formed as a material is, and refers in particular to a device without Difficulty nonwoven surface products (nonwovens, Composites) of fibers whose diameter is below 100 nanometers [nm] and which are referred to as nanofibers. Nonwoven sheet products produced in this way (Nonwovens, composites) have a wide range of applications, which also includes filters.

filter For example, you can also use the "merge method" be prepared, one of the methods for the production of conventional Fleeces. Filters made of fibers whose diameter several tens of microns, are mainly produced with such a conventional manufacturing method, and filters consisting of fibers with a diameter of several hundred Are formed the limit of what with the nanometer conventional methods can be produced. The manufacturing process, the can use an electrostatic spraying process, however, can Make nonwovens or composites of fibers which, as indicated above, thinner by one or two orders of magnitude are as those after the conventional manufacturing process, for example the "merger process" only one nozzle with a spray outlet opening used for electrostatic spraying, then you can only small filters of a few square centimeters can be made. Therefore, a structure in which only one nozzle with a Sprühaustrittöffnung is used in terms of mass production and on the Productivity not realistic. If filter with a Width of 100 cm or a corresponding size made by textile manufacturers and fabric manufacturers is it is necessary to use multiple nozzles, as it does for nonwoven products, ie nonwovens or composites, and films is the case with the conventional manufacturing process were manufactured.

Become uses multiple nozzles, but then the problem arises that the operation of electrostatic spraying due to the effects of disturbances, rejection phenomena and Like the charge becomes unstable and some or most of the several nozzles provided in some cases can not perform electrostatic spraying. It is therefore an object to have a stable electrostatic spraying process to allow using a plurality of nozzles, thus a device with multiple nozzles for electrostatic Spraying for a practical use and for Production of mass products is suitable.

In order to achieve the above object, a mechanism for suppressing the disturbance and repulsion charges, referred to as a charge distribution plate, is disclosed in US Pat Japanese Patent Application Laid-Open Publication No. 2002-201559 been proposed. However, the handling of the charge distribution plate is difficult because the position of the charge distribution plate for performing the electrostatic spraying operation must be changed depending on the applied voltage. In addition, when using a plurality of nozzles arranged in rows and columns, there is a problem that the ratio of the coating amount (amount of lamination) to the amount of spray, that is, the so-called collection efficiency, becomes lower when the charge distribution plate is used.

• Patentdokument 1: japanische Patentanmeldungs-Offenlegungsschrift Nr. 2002-201559
• Patentdokument 2: japanische Patentanmeldungs-Offenlegungsschrift Nr. H 8-153669 .

There is also a system in the Japanese Patent Application Publication No. H 8-153669 has been described in which electrodes are arranged on the nozzles and the mounting surface of an object, on which a material is sprayed, and in which a high voltage is applied between the two. In the system in which the electrodes are disposed on the nozzles and the installation surface and an electrostatic spray is performed on the object to which the material is sprayed as described above, the electrostatically sprayed material is laminated so as to cover the mounting surface, that is, the surface of the opposite electrode, and the efficiency of the electrostatic spraying operation gradually weakens. That is why it is with the manufacturing process, as in Japanese Patent Application Publication No. H 8-153669 is difficult to carry out electrostatic spraying with high precision for a long time, and the method is not suitable for mass production.

• Patent Document 1: Japanese Patent Application Laid-Open Publication No. 2002-201559
• Patent Document 2: Japanese Patent Application Laid-Open Publication No. H 8-153669 ,

Description of the invention

This by the invention solving problem

 charged and electrostatically sprayed material particles are attracted by a collector acting as a collector surface (Lamination) serves and charges a different Polarity, and then collected on the collector (laminated). Because the sprayed material particles are the same Polarity, they bump into each other of Coulomb's forces and are scattered and reach then the collector in a uniform state. If the material particles collect on the collector (to be laminated), their charges discharge into the collector. Even if the charges have been discharged, the collector must always be the height containing charges that are equivalent to the amount of charges of the material particles is because the polarity of the charges is different than that of the Charges of the material particles, or the collector must be grounded. The reason is that when the sprayed Material particles continuously attracted to the collector and on it be collected - in the case where the collector of the Charge amount of the material particles equivalent charge amount contains - the polarity of the collector charge of which the material particle is different, or if the Collector is grounded, no charges between the Sprühauspföffnungen the nozzles and the collector are accumulated. from that It follows that the material particles from the spray orifices evenly from the collector surface (Laminating) are attracted and an electrostatic Spraying is performed. If, however, increase the charges of the sprayed material particles, Charges accumulate between the spray outlet openings and the collector. Because the polarity of the as described above accumulated charges are the same as those of the still to be sprayed Particles of material collide according to Coulomb's Law off the charges and suppress the spraying from the spray orifice, leaving the Spray outlet openings of the nozzles no electrostatic spraying can take place. This phenomenon occurs in a similar way, whether it is a construction with one or more nozzles. The inventors of the present invention have experimented with devices for the electrostatic spraying performed once built with a nozzle and once with multiple nozzles were, and the inventors found that an electrostatic Spraying is stopped when the charge amount of the polymeric Material is increased by the applied voltage gradually is increased. However, since the amount of charge to be sprayed polymeric material in the electrostatic spraying apparatus with a nozzle is lower than in the device for electrostatic spraying with several nozzles, It is easier to use an electrostatic spray with a version of the device for electrostatic spraying with a nozzle.

Become multiple nozzles used to increase productivity increase, the amount of charge inevitably increases, the charges are repelled intensively, and in many cases will carry out an electrostatic spraying process prevented. Therefore, it is necessary to reduce the charge quantities more precisely, to lower the voltage to be applied. Will, however the voltage to be applied is lowered in this way, then occurs the problem is that the spray speed drops and the productivity decreases. In addition, the Repulsion forces between the charges required, so that at the spray outlet openings at the tips the nozzles a spraying arises. Becomes the charge amount reduced by the voltage to be applied is lowered are the repulsive forces required for spraying insufficient and the spraying process may be in some Cases are not carried out.

Thus, if electrostatic spraying is performed in the multi-nozzle configuration under the same conditions as the nozzle equipped configuration, for example the same voltage and spraying distance, then some or most of the multiple nozzles may not electrostatically spray in many cases To run. Therefore, the device for electrostatic spraying with multiple nozzles must be carried out An electrostatic spraying operation may have a particular configuration to allow electrostatic spraying to be performed as efficiently as with a single nozzle configuration.

at a conventional device for electrostatic spraying For example, the collector is parallel to the Sprühaustrittsöffnungen the multiple nozzles arranged, with the collector off a highly conductive material such as aluminum foil, so that Do not charge between the spray outlet openings and accumulate the collector, and / or the area of the Collector is designed as big as possible. But even with this kind of construction, the effect is in a certain way Degree limited and does not offer dramatic improvement. This kind of the structure thus offers no fundamental solution.

Furthermore offers the conventional device for electrostatic spraying only a low collection efficiency during the electrostatic spraying process and thus causes a problem that accumulation (lamination) only in designated local places not can be performed and that uncaught particles scattered around the device. The inventors are this kind of dispersion problem in the performance of electrostatic Spraying with a device noticed with a Acrylic cover or the like was provided. Such a problem, that means that the sprayed material particles do not (as Laminate) can be collected, of course caused a loss of material. In addition to this considered the health risks of the workers Be as large amounts of fibers of a few nanometers be scattered to several tens of nanometers in diameter.

Accordingly the present invention has the purpose of a device for electrostatic Spraying and a method of electrostatic spraying to provide an electrostatic spraying process perform stably when using a plurality of sprays, and who are able to mass produce products with high collection efficiency, excellent productivity, high accuracy and high security.

Means for releasing the problems

The Apparatus and method for electrostatic spraying according to the present invention are as follows described in order to solve various problems, those in the above-mentioned conventional devices occur for electrostatic spraying.

• eine Vielzahl von Spinneinheiten, von denen jede eine Vielzahl von Düsen aufweist, die zweidimensional angeordnet sind, um eine Polymerlösung, die eine polymere Substanz enthält und unter Verwendung eines Lösungsmittels als eine Flüssigkeit ausgebildet ist, elektrostatisch zu sprühen, und einen ersten Kollektor, der so angeordnet ist, dass er gegenüber der Vielzahl von Düsen mit einer dazwischenliegenden Isolierschicht angeordnet ist, wobei die Polarität der dem ersten Kollektor zugeführten Spannung sich von der Polarität der Spannung unterscheidet, die den Düsen zugeführt wird, oder der erste Kollektor an Massepotential geerdet ist,
• eine erste Spannungsquelle zum Anlegen einer vorbestimmten Hochspannung an die Düsen, und
• Kollektorabschnitte, die den Spinneinheiten zugeordnet sind und die eine Kollektorbahn bewegbar halten, wobei
• die Spinneinheit mit einem Mittel zur Bildung eines Luftstroms versehen ist, der in eine Richtung strömt, die im Wesentlichen orthogonal zu der Sprührichtung von den Düsen zu dem ersten Kollektor verläuft, um einen Luftstrom in Richtung der Kollektorbahn zu bilden. Die Vorrichtung zum elektrostatischen Sprühen gemäß der vorliegenden Erfindung, die wie oben beschrieben konfiguriert ist, kann elektrostatische Sprühvorgänge stabil und fortlaufend mit hoher Sammlungseffizienz ausführen.

The electrostatic spray apparatus according to the present invention comprises:

• a plurality of spinning units each having a plurality of nozzles arranged two-dimensionally to electrostatically spray a polymer solution containing a polymeric substance formed using a solvent as a liquid; and a first collector, the like is disposed opposite to the plurality of nozzles with an insulating layer therebetween, the polarity of the voltage applied to the first collector being different from the polarity of the voltage supplied to the nozzles, or the first collector grounded to ground potential,
• a first voltage source for applying a predetermined high voltage to the nozzles, and
• Collector sections which are associated with the spinning units and which hold a collector track movable, wherein
• the spinning unit is provided with means for forming an air flow which flows in a direction substantially orthogonal to the spraying direction from the nozzles to the first collector to form an air flow in the direction of the collector track. The electrostatic spray apparatus according to the present invention, which is configured as described above, can perform electrostatic spraying operations stably and continuously with high collection efficiency.

• Zuführen einer Polymerlösung, die eine polymere Substanz enthält und unter Verwendung eines Lösungsmittels als eine Flüssigkeit ausgebildet ist, an eine Vielzahl von zweidimensional angeordneten Düsen,
• Anlegen einer Hochspannung an die Düsen, um die Polymerlösung elektrostatisch aus den Düsen zu sprühen,
• Erzeugen eines Luftstroms, der in eine Richtung strömt, die im Wesentlichen orthogonal zu der Richtung des elektrostatischen Sprühens einer mit den Düsen ausgerüsteten Spinneinheit verläuft, und
• Zuführen des Luftstroms an die elektrostatisch gesprühte und aufgeladene polymere Substanz, so dass die polymere Substanz auf einer Kollektorbahn laminiert wird, die im Wesentlichen orthogonal zu der Richtung des Luftstroms angeordnet ist. Mit dem oben genannten Verfahren zum elektrostatischen Sprühen gemäß der vorliegenden Erfindung kann ein elektrostatischer Sprühvorgang stabil mit hoher Sammlungseffizienz ausgeführt werden.

The method of electrostatic spraying according to the present invention comprises the steps of

• Supplying a polymer solution containing a polymeric substance and formed using a solvent as a liquid to a plurality of two-dimensionally arranged nozzles,
• Applying a high voltage to the nozzles to electrostatically spray the polymer solution from the nozzles,
• Generating an air flow flowing in a direction substantially orthogonal to the direction of electrostatic spraying of a spinning unit equipped with the nozzles, and
• Supplying the air stream to the electrostatically sprayed and charged polymeric substance such that the polymeric substance is laminated on a collector track that is substantially orthogonal to the direction of the airflow. With the above-mentioned method of electrostatic spraying according to the present invention, electrostatic spraying can be performed stably with high collection efficiency.

Effect of the invention

The present invention can provide an apparatus and method for electrostatic spraying capable of producing mass products with high collection efficiency, excellent productivity and high accuracy, using a plurality of nozzles arranged two-dimensionally and serving as a spraying means.

Furthermore For example, the present invention may be an apparatus and a method to provide electrostatic spraying, which has a high Provide security because one during the electrostatic spraying process used organic solvent in a safe way can be recovered again.

Brief description of the drawings

1 Fig. 12 is a view schematically showing the structure of an electrostatic spray apparatus according to Embodiment 1 of the present invention;

2 Fig. 12 is a schematic sectional view showing a plurality of spinning units disposed on the channels of the electrostatic spray apparatus according to Embodiment 1;

3 FIG. 10 is a perspective view of the spinning unit of the electrostatic spray apparatus according to Embodiment 1; FIG.

4 FIG. 14 is a view of the installation surface of the spinning unit of the electrostatic spray apparatus according to Embodiment 1; FIG.

5 FIG. 12 is a view of the rear surface of the spinning unit of the electrostatic spray apparatus according to Embodiment 1; FIG.

6 FIG. 12 is a sectional view of a spray block and the surrounding area in the spinning unit of the electrostatic spray apparatus according to Embodiments 1 and. FIG

7 FIG. 10 is an exploded perspective view of the spray block and the surrounding area in the spinning unit of the electrostatic spray apparatus according to Embodiment 1. FIG.

Best way to execute the invention

It follows the detailed description of a preferred embodiment an apparatus and method for electrostatic spraying according to the present invention; this reference is made to the attached drawings.

Embodiment 1

1 FIG. 10 is a side view of the schematic configuration of an electrostatic spray apparatus according to the preferred embodiment 1 of the present invention. FIG. The electrostatic spray apparatus according to Embodiment 1 electrostatically sprays a solution containing a polymeric substance from nozzles to produce fibers thinner than 100 nanometers [nm], which are called nanofibers, and composites, nonwovens, made of nanofibers.

First, with reference to 1 the preparation of nanofiber nonwovens or nano-fiber composites by electrostatic spraying with the apparatus for electrostatic spraying according to Embodiment 1 of the present invention outlined. The production of nanofiber nonwovens requires a substrate that serves as the basis for the collection and lamination process of the nanofibers. A collector track 8th of an insulating resin, for example, polyethylene, is used as a substrate. This collector track 8th is from a supply spool 20 fed and from a take-up spool 21 over several intermediate roles 18 recorded, whose forwarding speed can be controlled. The electrostatic spray apparatus according to Embodiment 1 is constructed such that the forwarding speed of the collector path 8th depending on the thickness of the web, on the diameter and the material of the nanofibres, etc., in such a way that a wide range of transfer speeds, from several meters to several hundred meters per minute, is possible.

The collector track 8th serving as a substrate becomes in the area between feed coil 20 and take-up spool 21 over the majority of intermediate roles 18 transported. A plurality of spinning units 22 along the transport path is the collector track 8th arranged. The spinning units 22 are at the channels of collector sections 13 arranged the collector's belt 8th on which nanofibers are collected and laminated. While the collector track 8th the collector sections 13 happens inside, the nanofibers from the spinning units 22 on the collector track 8th laminated to a thickness of several hundred nanometers to several hundred micrometers.

As in 1 are shown are the spinning units 22 almost horizontal to the side surfaces of the channels of the collector sections 13 arranged and extending in the vertical or horizontal direction so that they are arranged orthogonally to the side surfaces; they are structured so that they are independent of each other. The number of too instal lierenden spinning units 22 can be chosen freely and depends on the production speed, the specifications etc. of a manufactured nanofiber structure. The apparatus for electrostatic spraying according to the embodiment 1 is constructed so that the number of spinning units to be installed 22 can be freely selected from a spinning unit to the maximum number of spinning units 22 in the collector section 13 can be arranged. Besides, it is possible if all spinning units 22 are installed to operate only freely selected spinning units, as the spinning units 22 are configured so that they can be operated independently. Therefore, from the electrostatic spray apparatus according to Embodiment 1, specific spinning units can be used 22 be removed for repair or maintenance without stopping production. In addition, if suddenly during the ongoing production of a fault on one of the spinning units 22 occurs, the production continues to run and it only need the spinning units involved in the disorder 22 to be stopped without taking the entire device out of service.

In addition, in the electrostatic spray apparatus according to Embodiment 1, it is not necessary that the spinning units 22 supplied materials are the same. Because each of the spinning units 22 with a material storage tank to be described later 15 (S. 2 ) is equipped to supply a material to the nozzles, it is possible different types of material to the respective spinning units 22 to guide and produce nonwovens or composites that consist of the different laminate materials. It is also possible to apply the same material to the respective spinning unit 22 to direct and the same material in the respective material storage tank 15 to maintain, and of course it is also possible always the same material to the respective spinning unit 22 to conduct by using a common feed tube with the appropriate spinning unit 22 is connected.

Next will be the construction and operation of the spinning units 22 in the electrostatic spray apparatus according to Embodiment 1.

2 FIG. 10 is a side sectional view of the configuration of the plurality of spinning units. FIG 22 in the collector section 13 are installed. 3 to 5 show the configuration of the spinning unit 22 ; 3 is a perspective view of the spinning unit 22 ; 4 is a front view of the front surface, the tion as installation area for the spinning unit 22 serves, and 5 is a rear view of the rear surface of the spinning unit 22 ,

As 2 shows is every spinning unit 22 with a stock tank 15 equipped to store a solution containing a polymeric substance, and the solution is removed from the stock tank 15 via a material supply pipe 14 to a plurality of nozzles 1 passed in the spinning unit 22 are provided. The majority of nozzles 1 is with a conductive plate 2 is integrally molded from a conductive material serving as a metal block, and the nozzles are arranged two-dimensionally in rows and columns (in a lattice-like pattern). In the electrostatic spray apparatus according to Embodiment 1, it is a function of the conductive plate 2 to serve as a solution tank for temporarily receiving the solution with the polymeric substance used as the material and the plurality of nozzles 1 is located on the lower side of the solution container. The described plurality of nozzles 1 and the conductive plate 2 make a spray block 30 which is used as a spray section.

A solution formed by mixing a polymeric substance such as polyurethane, which serves as the material of nanofibers, with a solvent such as toluene, becomes each of the material storage tanks 15 that are independent of each other on the corresponding spinning unit 22 are arranged, the conductive plate 2 of the spray block constructed as above 30 over the material supply pipe 14 fed.

Although the spray block 30 with the plurality of nozzles 1 and the conductive plate 2 In the apparatus for electrostatic spraying according to the embodiment 1 of a metal block, for example, made of aluminum or stainless steel, is integrally formed by pressing, it may also be produced by stamping. The nozzle 1 has a spray orifice of a predetermined diameter and is conically shaped to be tapered toward the lower end. In addition, the nozzle 1 designed so that its spray orifice with the solution container of the conductive plate 2 communicates.

The conductive plate 2 is configured such that a high voltage (for example, a high voltage between several kV to several tens of kV) therefrom from a first voltage source 40 is created and that its upper area where the nozzles 1 are not arranged, with an insulating cover 9 is covered by an insulating synthetic resin. With this insulating cover 9 the solution becomes in the solution tank of the conductive plate 2 protected against contamination by dust or the like. In addition, with the insulating cover 9 the spray block 30 in the spinning unit 22 opposite the housing 10 the spinning unit 22 isolated and protected.

On the entire lower surface inside the spinning unit 22 are an insulating layer 5 and a first collector formed of a thin metal plate 4 from above, in this order, so stacked that they are the nozzles 1 are opposite. In the electrostatic spray apparatus according to Embodiment 1, the first collector 4 although grounded, be configured to be supplied with a voltage whose polarity is different from that of the spray block 30 different.

6 is a sectional view of the spray section of the spinning unit 22 the apparatus for electrostatic spraying according to the embodiment 1, the spray block 30 , the insulating cover 9 for covering the spray block and so on. In addition to the spray block 30 and the insulating cover 9 are the material supply pipe 14 and the stock tank 15 present in the spray section. 7 is an exploded perspective view of the in 6 shown spray section.

The conductive plate 2 that with the several nozzles 1 is integrally formed, has the shape of a tray with recess. In its bottom surface portion, each of the plurality of nozzles 1 equipped with a conically shaped spray orifice which tapers towards the exit end, and the nozzles are arranged two-dimensionally linearly in rows and columns; in other words, the multiple nozzles 1 are arranged at the intersections of the grid-like pattern at equal intervals. The spray block 30 who the leading plate 2 and the plurality of nozzles 1 has been formed from a metal block by press working as described above. The solution containing the polymeric substance is present in the space of the recess of the tray section as a supply, that is, in the concave space in the conductive plate 2 and the solution is removed from the stock tank 15 over the material supply pipe 14 guided in a manner to the recessed tray section, that the amount of solution in the recessed tray section is kept constant. The majority of nozzles 1 is at the bottom surface of the conductive plate 2 arranged at equal intervals in the row and column direction. In the embodiment 1, 48 nozzles 1 in four rows and twelve columns on the conductive plate 2 educated; the conductive plate 2 measures 250 mm (width) × 500 mm (length) × 180 mm (height). The above-mentioned size of the conductive plate 2 and the number of nozzles 1 are merely examples and will depend on the specifications, the production rate, etc. of the product to be manufactured, the nozzles 1 applied voltage and the intensity of a substantially orthogonal to the spray direction of the nozzles 1 flowing airflow 17 suitably selected.

Generally speaking, a material that is easy to work and conduct, such as stainless steel, is the material of the spray block 30 to prefer. Is the inner diameter of the spray orifice of the nozzle 1 too small, there is a risk that the spray orifice will be blocked; On the other hand, if the inside diameter is too large, liquid may drip out. Therefore, the inner diameter is preferably in the range of 0.1 to 1.0 mm. The spray outlet opening of the nozzle 1 Serving through opening is created by precise drilling. During the pressing process, the nozzle becomes 1 shaped so as to have a height (distance between the end serving as a spray discharge port and the neck of the conical-shaped nozzle 1 ) of at least 5 mm in order to take advantage of the property of concentrating charges on tapered areas. The upper area of the spray block 30 with the conductive plate 2 and the nozzles formed as above 1 is with the insulating cover 9 covered by an insulating resin, and the spray block 30 and the insulating cover 9 are attached to each other.

The insulating cover 9 serves as a lid for covering the concave space contained in the conductive plate 2 is formed in a flat shell shape, and prevents in the way that from the material storage tank 15 over the material supply pipe 14 in the concave space in the conductive plate 2 Injected solution containing the polymeric substance is contaminated by contaminating substances, etc. In the concave space in the conductive plate 2 solution present as a supply flows into the integral at the bottom portion of the conductive plate 2 arranged nozzles 1 and is sprayed.

In the electrostatic spray apparatus according to Embodiment 1, since an organic solvent such as toluene is used to dissolve the polymeric substance, etc., it is preferable that the portions that come in contact with the solution be, for example, the insulating cover 9 , the material of the feed tube 14 and the stock tank 15 are made of corrosion-resistant synthetic resin materials, for example fluororesin resin, PE (polyethylene) and PP (polypropylene resin).

The solution containing the polymeric substance coming from the material storage tank 15 to the conductive plate 2 over the material supply pipe 14 is supplied to be uniform to the at the bottom surface of the concave space in the conductive plate 2 provided corresponding nozzle 1 directed. The solution level is constantly detected using a common level detector, so that all nozzles 1 are sufficiently filled with the solution, in the concave space in the conductive plate 2 a predetermined level is maintained and the solution is supplied when the level is below a level decreasing level.

As in 7 are shown in the insulating cover 9 an installation opening 12 in which the material supply pipe 14 is installed, and a concave portion formed in the solution container of the spray block 30 is fitted to hermetically seal the solution container. The material supply pipe 14 and the spray block 30 are configured to light off the insulating cover 9 are to be removed, so that there are structures that offer excellent maintainability, such as for cleaning.

The housing, which is the outer surface of the spinning unit 22 is made of a synthetic resin serving as an insulating material and having a rigidity, whereby it can bear its own weight; it is with a flange 11 equipped so that the housing on the channel of the collector section 13 is installed. The spinning unit 22 is constructed so that the flange 11 of the housing 10 bolted to the channel via bolts to allow easy removal. An opening that acts as an air inlet 6 is used and for forming an air flow is in the back surface of the housing 10 provided, that is, on the side, which is the flange 11 opposite. An electrical opposite the housing 10 isolated metal net 16 is at the air inlet opening 6 arranged. The metal net 16 is with a second voltage source 50 connected. A voltage lower than that of the above-mentioned first voltage source 40 supplied voltage and whose polarity is identical, is from the second voltage source 50 fed. The reference potential is the potential of the wall surface of the channel, which is the collector section 13 represents, and the reference potential of the first voltage source 40 and that of the second voltage source 50 is also the potential on the wall surface of the channel. In addition, the reference potential is generally the ground potential.

When from the first voltage source 40 a high voltage to the conductive plate 2 is applied, charges are generated by an electrostatic field. Since the charges have the property of concentrating on the tapered areas, they concentrate at the tip tips of the nozzles 1 , The to the conductive plate 2 The high voltage to be applied is determined depending on the material and the viscosity of the solution, the material and diameter of the nanofibers to be produced, the production environment (temperature and humidity), etc., ranging from several kV to several tens of kV. Since the charges as described above at the tips of the nozzles 1 concentrate, the surface tension ranges of the liquids at the tips of the nozzles 1 charged. So there are tiny charged particles 3 at the tips of the nozzles 1 from these tips of the nozzles 1 separated and as charged liquid droplets due to the strong electric field between the nozzles 1 and the first collector 4 sprayed, wherein the collector is arranged so that it passes through the insulating layer 5 separated from the nozzles 1 is arranged opposite. Since the sprayed charged liquid droplets have the same polarity, they repel each other due to the Coulomb forces acting between them, distribute evenly, and then move towards the first collector 4 dressed.

The distance between the tips of the nozzles 1 and the first collector is preferably in the range of about ten centimeters to several tens of centimeters. In Embodiment 1, the distance is set to 20 cm. The distance between the tips of the nozzles 1 and the first collector 4 is determined according to the specifications of the nanofibers to be produced, the value of the voltage to be applied, etc. The positions of first collector 4 , the insulating layer 5 and the nozzles 1 can therefore be designed relatively adjustable.

Because the sprayed liquid particles coming from the tips of the nozzles 1 are charged as described above and the charges are attracted by an electrode of the other polarity, the liquid particles to the first collector 4 attracted. While the charges are on their way towards the first collector 4 Because of the charge of the liquid particles, the liquid particles are broken up into tiny particles many times by electrostatic repulsion. When the liquid particles are divided into tiny particles in this way, the solvent used to dissolve the material evaporates and only the nanofiber material remains. The material is in the state of fibers called nanofibers, which have a diameter of a few nanometers to tens of nanometers.

Even if the solution containing the polymeric substance has transitioned to the state of nanofibers as described above, that is, even if the solution is transformed to the solid state, those of the nozzles remain 1 given charges and the nanofibers remain charged., In the spinning unit 22 The apparatus for electrostatic spraying according to Embodiment 1 is the insulating layer 5 between the nozzles 1 and the first collector 4 arranged, with a distance of several millimeters to the first collector 4 Has. The distance between the first collector 4 and the insulating layer 5 is within a range of a few millimeters to several tens of millimeters, taking into account the material as the polymeric substance, the size of the charges, etc. are selected. The insulating layer 5 is made of a dielectric material and has the shape of a thin layer of material or a thin plate.

The insulating layer 5 has the property of a dielectric material; in other words, it has the property of inducing electrical polarization through an external electric field, that is, the property of indicating induced polarity. Thus, when a high voltage is applied, the surface of the conductive plate is charged 2 , which serves as a metal block, and induces a polarization. In the state of induced polarization, the surface of the insulating layer has 5 , which are the spray orifices of the nozzles 1 opposite, the same polarity as the metal block. Since that from the spray orifices of the nozzles 1 sprayed and transformed into nanofibers material has the same polarity as the insulating layer 5 , the material comes off the charged insulating layer 5 from the Coulombic forces that "charges of the same polarity repel each other." It follows that the material transformed into nanofibers exists in a space of about ten centimeters to several tens of centimeters between the spray orifices of the nozzles 1 and the insulating layer 5 floats.

The second voltage source 50 is with the metal net 16 connected to the rear surface of the spinning unit 22 the device for electrostatic spraying according to Embodiment 1 is arranged; to the metal net 16 a voltage of several tens of volts to several hundred volts is applied. To the metal net 16 a voltage of the same polarity as that applied to the nozzles is applied 1 has applied voltage. On the other hand, a voltage of several volts to a second collector 7 created in the collector section 13 arranged so that it is the metal net 16 opposite, and the polarity of the voltage differs from that of the metal mesh 16 , The to the second collector 7 applied voltage is set depending on the material of the polymeric substance, the size of their charge, etc. in a range of several volts to several hundreds of volts or at ground potential serving as a reference potential. Suspended between the spray orifices of the nozzles 1 and the insulating layer 5 charged nanofibers are from the metal mesh 16 repelled with the same polarity as the nanofibers and due to Coulomb's forces to the second collector 7 drawn, which has the other polarity.

In addition, the electrostatic spray apparatus according to Embodiment 1 is constructed so that dry air passes through at the collector portion 13 installed metal net 16 the spinning unit 22 blown and in the direction of the second collector 7 in the channel of the collector section 13 is directed. The pressure in the channel of the collector section 13 is set lower than the atmospheric pressure of the environment, that is, there is a negative pressure, so that the nanofibers can be safely collected. In addition, the moisture content of the spinning unit 22 introduced dry air adjusted to 40% or less, so that in the spinning unit 22 Floating nanofibers are transferred to the dry state.

As described above, the electrostatic spray apparatus according to Embodiment 1 is constructed so as to have the nanofibers in the collector portion 13 This can be safely collected, that the pressure in the collector section 13 set to a negative pressure value that is the polarity of the second collector 7 adjusted so that they are different from the metal net 16 differs or is set to ground potential, and that dry air from the metal mesh 16 to the channel of the collector section 13 is supplied. The electrostatic spray apparatus according to Embodiment 1 is configured such that one fan for each spinning unit 22 is provided to supply dry indoor air (humidity 40% or less). However, the electrostatic spraying apparatus may also be constructed to provide a channel for supplying dry air at the desired moisture content from outside the apparatus.

In Embodiment 1, the metal net becomes 16 used to introduce dry air from the back surface of the spinning unit 22 in a way to allow that airflow 17 towards the collector section 13 is generated safely. Other components can also be used with this type of function. For example, it is also possible to use a conductive element having its structure through a plurality of through-holes in one of the housings 10 receives isolated metal plate.

The spinning unit 22 the electrostatic spray apparatus according to the embodiment 1 is with an air inlet opening 6 provided with a metal net structure serving as an air flow forming means. The air inlet opening 6 However, according to the present invention may also have a different structure than a metal mesh. For example, the air inlet opening 6 be constructed so that dry air, the pressure of which is to be adjusted, can be introduced from an air inlet opening at the end of the surface of the back of the spray block 30 is trained. In this case, the metal block in which the air inlet opening 6 is formed with the first voltage source 40 verbun and to the metal block is applied a voltage of the same polarity as the nozzles 1 to have. It follows that the air flow 17 from the air inlet opening 6 to the collector section 13 is generated in the space between the nozzles 1 and the insulating layer 5 lies so that the charged nanofibers from the air inlet 6 out to the second collector 7 be attracted to.

As described above, those in the spinning unit 22 floating nanofibers towards the collector section 13 guided and from the surface of the collector track 8th that go along the second collector 7 is transported, tightened, collected and laminated. It follows that a nanofiber molded polymeric web or composite can be made. The lower the transport speed of the collector track 8th The longer the time that is required is the collector track 8th the spinning unit 22 The larger the amount of nanofibers accumulated and laminated per unit area. As a result, it is possible to make the polymeric nonwoven fabric formed of nanofibers or the corresponding composite which is the product to be made thicker. In addition, the web or composite also gets thicker the more spinning units 22 at the collector section 13 are installed. It is thus possible to change the thickness of the nanofiber polymeric sheet by changing the number of spinning units installed 22 and / or by changing the transport speed of the collector track 8th to control.

Since those from the nozzles 1 sprayed nanofibers on the collector track 8th along the surface of the second collector 7 transported, collected and laminated, the charges of tiny charged particles accumulate 3 the nanofibers are not in the space between the spray orifices of the nozzles 1 and the insulating layer 5 made of dielectric material, but along the air flow 17 on the second collector 7 transfer. As a result, with the electrostatic spray apparatus according to Embodiment 1, the material is continuously discharged from the nozzles 1 sprayed, and it is thus possible to produce a desired non-woven or a corresponding composite.

The occurring in the above-mentioned conventional devices Problem, namely that charges between the Sprühaustrittsöffnungen and the collector accumulate accumulated charges repel and re-charged material particles are not can be sprayed out the nozzles, becomes with the use of the above-described device for electrostatic spraying solved according to the embodiment 1.

In the electrostatic spray apparatus according to Embodiment 1, dry air is introduced through the air inlet port 6 the spinning unit 22 at the collector section 13 is installed, inserted, and that in the collector section 13 prevailing pressure is lowered below that of the ambient air pressure, that is, there is negative pressure to collect the nanofibers. The speed of the supplied dry air may be low, about several centimeters per second; It should be set so that the nanofibers gently on the collector track 8th be collected and the air flow inside the spinning unit 22 not disturbed. A high air flow speed of several tens of centimeters per second is unfavorable because the already accumulated nanofibers are moved by the air pressure and additional static electricity is generated.

The structure for supplying dry air according to the embodiment 1 is not only used as a measure against scattering of the nanofibers, but also used to allow trapping of the organic solvent contained in the material solution. Since that in the execution 1 When the material used, a polymeric substance as described above, is used in the form of a solution, an organic solvent or the like is used as a solvent, and during production, a large amount of the organic solvent is consumed. In the conventional plants, trapping of the organic solvent which evaporates during the spraying process is not considered. Health hazards, fires, etc. that occur as a result of the evaporation of organic solvents, as well as health risks to people due to the dispersion of nanofibers are serious problems. In the electrostatic spray apparatus according to Embodiment 1, a recovery unit 19 at the upper end of the collector section 13 arranged so that the dry air containing the organic solvent or the like coming from the interior of the spinning units 22 through the collector section 13 flows, is captured. This recovery unit 19 is constructed so that a fan provided in a recovery apparatus (not shown) outside the electrostatic spraying apparatus is used to discharge the dry air.

Of the Process of collecting the nanofibers in the device for electrostatic Spraying according to the embodiment 1 will be described in more detail below.

Dry air with a moisture content of 40% or less is added to each spinning unit 22 over the air inlet opening 6 and via feeder Tel as tube and channel introduced, and the inside of the spinning unit 22 communicating collector section 13 prevailing pressure is with the help of the recovery unit 19 set to a negative pressure value. In this configuration, this is done in the spinning unit 22 Evaporated organic solvents, etc. are not discharged outside the device, but in the collector section 13 guided and using the recovery unit 19 collected. As described above, the electrostatic spray apparatus according to Embodiment 1 is constructed so that safe recovery of the evaporated organic solvent can be achieved without the solvent leaking outside of the apparatus. An exhaust fan according to Embodiment 1 is inside the recovery unit 19 as arranged in the case of a general purpose drafting chamber. The speed of the inside of the collector section 13 in the direction of the recovery unit 19 flowing air ranges from about a few centimeters per second up to 10 centimeters per second, and the pressure in the collector section 13 is set to a weak negative pressure, which is lower by about 0.02 kPa than the pressure in the spinning unit 22 ,

As described above, the electrostatic spray apparatus according to Embodiment 1 is configured such that the pressure within the recovery unit is set to a negative pressure such that the pressure within the collector portion 13 held in a manner at a negative pressure that the manufactured nanofibers on the collector track 8th within the collector section 13 be laminated and that in the spinning unit 22 Evaporated organic solvents, etc. through the channel of the collector section 13 is recovered.

In the electrostatic spray apparatus according to Embodiment 1, it is an important feature that the dry air from each spinning unit 22 to the channel of the collector section 13 to be led. However, the structure should definitely be such that the air flow within the spinning unit 22 mainly from the air inlet opening 6 to the collector track 8th is generated stable.

The electrostatic spray apparatus according to Embodiment 1 is provided with a control device capable of providing the respective spinning unit 22 operate independently, and which is designed so that they are the spinning units required according to a product to be manufactured 22 and only the selected spinning units 22 can operate.

As As described above, the device for electrostatic spraying According to the present invention stable electrostatic Spray processes using the plurality of nozzles run and the desired products in mass production produce.

Furthermore allows the device for electrostatic spraying according to the present invention as described above the mass production of nonwovens and composites formed from nanofibres and from filters of several nanometers [nm] to several tens Nanometers [nm] diameter. When using the device for electrostatic spraying according to the present invention Accordingly, filters made according to the invention may of course be understood meet the requirements for conventional filters and may be dust, bacteria, for example anthrax pathogens, eliminate that are not eliminated when using conventional filters could.

additionally have those with the device for electrostatic spraying produced according to the present invention Filter not only in terms of "elimination", but also with regard to "selection" an excellent effect. The fact that particles of several nanometers in diameter Captures that not only allows unwanted Substances are eliminated, but also nanoparticles taken out become. For example, when it comes to diamond abrasive grains and the like, then becomes the conventional grinding accuracy improved by two or more orders of magnitude, if only the abrasive grains of tens of nanometers [nm] diameter can be selected. Furthermore Can be used with the device for electrostatic spraying produced according to the present invention Filters can also be used for drug or drug separation. As stated above, the electrostatic spraying apparatus and method excellent according to the present invention Characteristics of "selection" on the nano-level.

About that In addition, those using the device for electrostatic spraying according to the present invention Invention products also in the regenerative Medicine for the production of "artificial biological Membranes "and the like are used, but is located Medicine is currently still in the research stage. It is to be expected that the present invention also in this specific field proves useful.

Industrial applicability

The electrostatic spraying apparatus according to the present invention performs an electrostatic spraying operation using egg a plurality of nozzles stable out; it is therefore useful for facilities intended for mass production.

Summary

A Apparatus for electrostatic spraying is designed that a variety of spinning units, each of which is a variety from two-dimensionally arranged nozzles to the electrostatic Spraying a polymeric solution, and a first collector, the plurality of nozzles, with a interposed insulating layer, at collector sections are installed to hold a moving collector track so an air flow orthogonal to the spray direction of the Nozzles to the first collector and to the collector layer in the spinning unit is formed.

1

jet

2

senior plate

3

charged particle

4

first collector

5

insulating

6

Air inlet opening

7

second collector

8th

collecting sheet

9

insulating

10

casing

11

flange

12

installation opening

13

collector section

14

material supply

15

Material storage tank

16

metal mesh

17

airflow

18

intermediate wheel

19

Recovery unit

20

feed spool

21

up spool

22

spinning unit

30

Spray block

40

first voltage source

50

second voltage source

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - JP 2002-201559 [0005, 0006]
• - JP 8-153669 [0006, 0006, 0006]

Claims (20)

Device for electrostatic spraying with: one Variety of spinning units, each of which has a variety of nozzles arranged two-dimensionally to form a polymer solution, containing a polymeric substance and using a solvent is formed as a liquid is to spray electrostatically, and a first collector, which is arranged so that it faces the plurality of Nozzles arranged with an intermediate insulating layer is, wherein the polarity of the voltage applied to the first collector is different from the polarity of the voltage, the is supplied to the nozzles, or the first collector grounded at ground potential, a first voltage source for applying a predetermined high voltage to the nozzles, and a collector section associated with the spinning units is and that keeps a collector track movable, in which the spinning unit provided with a means for forming an air flow that flows in a direction that is substantially orthogonal to the spray direction from the nozzles to the first one Collector runs to a flow of air in the direction of To form collector track. Device for electrostatic spraying after Claim 1, wherein: the means for forming an air flow a Air intake opening at a position opposite the installation surface of the spinning unit, the is installed on the collector section, as well as one at the air inlet opening provided conductive part, to which a voltage source with connected to the same polarity as the nozzles supplied voltage, second, conductive Collectors behind the collector track in the collector sections are arranged and the polarity of the second collector supplied voltage varies depending on the polarity of the Voltage that differs from the conductive part at the Air inlet port is supplied, or the second Collector is grounded to ground potential, and the collector track along the surfaces of the second collectors is performed. Device for electrostatic spraying after Claim 1, wherein: the spinning unit is a conductive Plate of conductive metal, which is integral with the nozzle is formed, wherein the polymer solution in the concave portion formed in the conductive plate is collected and that the polymer solution to the nozzles is supplied. Device for electrostatic spraying after Claim 1, wherein the spinning unit contains the following units: the first collector, which is arranged so that it the nozzles is opposite the insulating layer between the the nozzles and the first collector is arranged, and the Air intake opening on the surface opposite the Installation surface is formed on the collector section is installed to allow a flow of air towards the collector section to generate in a direction that is substantially orthogonal to the spray direction of the polymeric substance is located. Device for electrostatic spraying after Claim 1, further comprising: a supply reel on which the Collector web is wound up as a roll, and a take-up spool for receiving the collector track coming from the supply reel fed and moved within the collector section and on which the polymeric substance is laminated. Device for electrostatic spraying after Claim 2, wherein the plurality of spinning units each on the Collector section are installed on the collector track in a direction substantially orthogonal to the direction of the air flow is arranged, and the second collector of the collector section attracts the electrostatically sprayed polymeric substance, so that the polymeric substance is laminated on the collector web, to thereby form a polymeric sheet. Device for electrostatic spraying after Claim 1, wherein the pressure within the collector sections on a negative pressure is set which is lower than the ambient air pressure. Device for electrostatic spraying after Claim 1, wherein the collector sections each with a recovery unit equipped with the air contained in the spinning units flows to the solvent contained in the polymer solution regain. Device for electrostatic spraying after Claim 1, wherein the plurality of spinning units in the direction of movement the collector track are arranged sequentially continuously. Device for electrostatic spraying after Claim 1, wherein the height of the nozzle 5 mm or is more and the inner diameter of the spray orifice at the opening of the nozzle in the range of 0.1 to 1.0 mm. Device for electrostatic spraying after Claim 1, wherein the installed on the collector sections Spinning units are arranged detachably. Method for electrostatic spraying with the following steps: Supplying a polymer solution containing a polymeric substance and using a solvent as a liquid to a plurality of two-dimensionally arranged nozzles, applying a high voltage to the nozzles to electrostatically spray the polymer solution from the nozzles, generating an air stream flows in a direction substantially orthogonal to the direction of electrostatic spraying in each of the spinning units equipped with the nozzles, and supplying the air flow to the electrostatically sprayed and charged polymeric substance so that the polymeric substance is laminated on a collector web is arranged substantially orthogonal to the direction of the air flow. Method for electrostatic spraying after Claim 12, comprising the step of laminating the polymeric substance on the collector track by moving the electrostatically sprayed and charged polymeric substance in a direction orthogonal to the spraying direction of the nozzles by means of Coulomb shear Forces. Method for electrostatic spraying after Claim 12, wherein in the step of supplying the polymer solution, which contains the polymeric substance and the use a solvent is formed as a liquid is, to the large number of nozzles running the stock quantity monitored the polymer solution and the level of Polymer solution is kept constant. Method for electrostatic spraying after Claim 12, wherein the polarity of the first, opposite the collector arranged collector supplied voltage is different from the polarity of the voltage, the is supplied to the nozzles, or wherein the first Collector grounded at ground potential to attract forces for attracting charged and separated nozzles To produce liquid droplets that are electrostatic sprayed and formed into the smallest charged particles. Method for electrostatic spraying after Claim 12, wherein the polarity of the second collector, along the side of the collector track opposite the side is arranged, on which the polymeric substance is laminated, supplied voltage varies depending on the polarity of the Voltage is different, which fed to the nozzles or where the second collector is grounded to ground potential is to attract and attract attractions to attract the nozzle separate liquid droplets to generate electrostatically sprayed and to smallest be formed charged particles. Method for electrostatic spraying after Claim 12, comprising the step of recovering in the polymer solution contained solvent from the air streams the spinning units. Method for electrostatic spraying after Claim 12, comprising the step of laminating the polymeric substance on the same collector track by independent operation the plurality of spinning units having the nozzles. Method for electrostatic spraying after Claim 18, including the step of controlling the operating conditions the variety of spinning units depending on the specifications of a polymeric sheet to be produced. Method for electrostatic spraying after Claim 18, comprising the step of bringing another polymer Substance as a laminate on the collector web in at least one of the Variety of spinning units.