This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2016-221299, filed on Nov. 14, 2016, and the PCT Patent Application PCT/JP2017/032478, filed on Sep. 8, 2017; the entire contents of which are incorporated herein by reference.
An embodiment of the invention relates to an electrospinning apparatus.
There is an electrospinning apparatus that deposits a fine fiber on the surface of a member by electrospinning (also called electric field spinning, charge-induced spinning, etc.).
A nozzle head that includes multiple nozzles discharging a source material liquid is provided in the electrospinning apparatus. Also, an electrospinning apparatus including a nozzle head and a member having a band configuration has been proposed. The member and the nozzle head are provided to oppose each other. In the electrospinning apparatus that includes the member having the band configuration, the fiber is deposited on the surface of the member having the band configuration while moving the member having the band configuration. Thus, a deposited body that includes the fiber can be produced continuously; therefore, the productivity of the deposited body can be increased.
In such a case, the production amount of the deposited body per unit time or per unit surface area can be increased by increasing the number of nozzle heads. However, if the number of nozzle heads is simply increased, this may cause an enlargement of the electrospinning apparatus.
Therefore, it has been desirable to develop an electrospinning apparatus in which improvement of the productivity and better space conservation can be realized.
An electrospinning apparatus according to an embodiment is configured to deposit a fiber on a collector or a member. The electrospinning apparatus includes a first nozzle head provided on one side of the collector or the member, and a second nozzle head provided on the side opposite to the first nozzle head with the collector or the member interposed. The first nozzle head and the second nozzle head are at a section where the collector or the member moves in a direction tilted with respect to a horizontal direction.
Embodiments will now be illustrated with reference to the drawings. Similar components in the drawings are marked with the same reference numerals; and a detailed description is omitted as appropriate.
An electrospinning apparatus 1 that includes a so-called needle-type nozzle head will now be illustrated as an example. However, the configuration of the nozzle provided in the nozzle head is not limited to a needle-like configuration.
For example, the nozzle that is provided in the nozzle head may be a nozzle having a circular conic configuration, etc. In such a case, if a nozzle having a needle-like configuration is used, electric field concentration occurs easily at the vicinity of the outlet of the nozzle; therefore, the strength of the electric field generated between the nozzle and the collector becomes high. On the other hand, if a nozzle having a circular conic configuration is used, the mechanical strength of the nozzle can be increased. Also, because the tip of the nozzle having the circular conic configuration can be sharp, the strength of the electric field generated between the nozzle and the collector becomes high similarly to the nozzle having the needle-like configuration.
Further, the nozzle head may be a so-called blade-type nozzle head, etc. If a blade-type nozzle head is used, the mechanical strength can be increased; therefore, damage of the nozzle head when cleaning, etc., can be suppressed. Also, the cleaning of the nozzle head is easy. The configuration of the blade-type nozzle head is not particularly limited and may be, for example, a rectangular parallelepiped configuration or a circular arc-like configuration.
As shown in
The first nozzle head 2a is provided on one side of the collector 5. For example, the first nozzle head 2a is provided above the collector 5. The first nozzle head 2a opposes a first surface 5a of the collector 5.
The second nozzle head 2b is provided on the side opposite to the first nozzle head 2a with the collector 5 interposed. For example, the second nozzle head 2b is provided below the collector 5. The second nozzle head 2b opposes a second surface 5b of the collector 5 on the side opposite to the first surface 5a.
In the case of the components illustrated in
The first nozzle head 2a and the second nozzle head 2b include nozzles 20, connectors 21, and main parts 22.
The nozzle 20 has a needle-like configuration. A hole for discharging the source material liquid is provided in the interior of the nozzle 20. The hole for discharging the source material liquid communicates between the end portion of the nozzle 20 on the connector 21 side and the end portion (the tip) of the nozzle 20 on the collector 5 side. The opening of the hole for discharging the source material liquid on the collector 5 side is an outlet 20a.
Although the outer diameter dimension (in the case where the nozzle 20 has a cylindrical configuration, the diametrical dimension) of the nozzle 20 is not particularly limited, it is favorable for the outer diameter dimension to be small. If the outer diameter dimension is set to be small, electric field concentration occurs easily at the vicinity of the outlet 20a of the nozzle 20. If the electric field concentration occurs at the vicinity of the outlet 20a of the nozzle 20, the strength of the electric field generated between the nozzle 20 and the collector 5 can be increased compared to the case where the outer diameter dimension of the nozzle 20 is large. Therefore, the voltage that is applied by the power supply 5 can be set to be low compared to the case where the outer diameter dimension of the nozzle 20 is large. In other words, the drive voltage can be reduced compared to the case where the outer diameter dimension of the nozzle 20 is large. In such a case, for example, the outer diameter dimension of the nozzle 20 can be set to about 0.3 mm to 1.3 mm.
The dimension (in the case where the outlet 20a is a circle, the diametrical dimension) of the outlet 20a is not particularly limited. The dimension of the outlet 20a can be modified appropriately according to the cross-sectional dimension of a fiber 100 to be formed. For example, the dimension of the outlet 20a (the inner diameter dimension of the nozzle 20) can be set to about 0.1 mm to 1 mm.
The nozzle 20 is formed from a conductive material. It is favorable for the material of the nozzle 20 to be conductive and to have resistance to the source material liquid described below. For example, the nozzle 20 can be formed from stainless steel, etc.
The number of the nozzles 20 is not particularly limited and can be modified appropriately according to the size of the collector 5, etc. It is sufficient for at least one nozzle 20 to be provided.
In the case where multiple nozzles 20 are provided, the multiple nozzles 20 are provided to be arranged at a prescribed spacing. For example, the multiple nozzles 20 can be provided to be arranged in a direction orthogonal to a movement direction 50 of the collector 5. Also, the arrangement form of the multiple nozzles 20 is not particularly limited. For example, the multiple nozzles 20 also can be provided to be arranged in one column, can be provided to be arranged in multiple columns, can be provided to be arranged on a circumference or on concentric circles, or can be provided to be arranged in a staggered configuration or a matrix configuration.
The connector 21 is provided between the nozzle 20 and the main part 22. A hole for supplying the source material liquid from the main part 22 to the nozzle 20 is provided in the interior of the connector 21. The hole that is provided in the interior of the connector 21 communicates with the hole provided in the interior of the nozzle 20 and the space provided in the interior of the main part 22.
The connector 21 is formed from a conductive material. It is favorable for the material of the connector 21 to be conductive and to have resistance to the source material liquid. For example, the connector 21 can be formed from stainless steel, etc.
In the case where the voltage is directly applied to the nozzle 20, it is not always necessary for the connector 21 to be formed from a conductive material.
The connector 21 is not always necessary; and the nozzle 20 may be provided directly at the main part 22.
However, there are cases where the source material liquid that is discharged adheres to the end portion of the nozzle 20 on the outlet 20a side and to the vicinity of the end portion. Therefore, it is favorable to perform, as necessary or regularly, cleaning of the end portion of the nozzle 20 on the outlet 20a side and the vicinity of the end portion.
In such a case, the end portion of the nozzle 20 on the connector 21 side can be fixed to the connector 21; and the connector 21 can be provided detachably at the main part 22. For example, an external-thread screw can be provided in the end portion of the connector 21 on the main part 22 side; and an internal-thread tap can be provided in the side surface of the main part 22. Also, the connector 21 can be provided detachably at the main part 22 by using a luer taper (luer taper) (also called a luer adapter, a luer lock, a luer connector, a luer fit, etc.). For example, a female luer (female luer) can be provided on the main part 22 side of the connector 21; and a male luer (male luer) can be provided on the side surface of the main part 22. In other words, the connector 21 may be connected to the main part 22 by using a screw or a luer taper.
A space in which the source material liquid is stored is provided in the interior of the main part 22. Although the configuration of the main part 22 is not particularly limited, the main part 22 can have a rod configuration in the case where the multiple nozzles 20 are provided. For example, the main part 22 that has the rod configuration can extend in a direction orthogonal to the movement direction 50 of the collector 5. The main part 22 that has the rod configuration can be provided to be parallel to the first surface 5a or the second surface 5b of the collector 5.
Also, a supply port 22a is provided in the main part 22. The source material liquid that is supplied from the source material liquid supplier 3 is introduced to the interior of the main part 22 via the supply port 22a. The number and the arrangement positions of the supply ports 22a are not particularly limited. For example, the supply port 22a can be provided on the side opposite to the side where the nozzle 20 of the main part 22 is provided.
It is favorable for the material of the main part 22 to be conductive and to have resistance to the source material liquid. For example, the main part 22 can be formed from stainless steel, etc.
The source material liquid supplier 3 includes a container 31, a supplier 32, a source material liquid controller 33, and a pipe 34.
The container 31 stores the source material liquid. The container 31 is formed from a material having resistance to the source material liquid. For example, the container 31 can be formed from stainless steel, etc.
The source material liquid is a polymeric substance dissolved in a solvent.
The polymeric substance is not particularly limited and can be modified appropriately according to the material properties of the fiber 100 to be formed. The polymeric substance can be, for example, polypropylene, polyethylene, polystyrene, polyethylene terephthalate, polyvinyl chloride, polycarbonate, nylon, aramid, etc.
It is sufficient for the solvent to be able to dissolve the polymeric substance. The solvent can be modified appropriately according to the polymeric substance to be dissolved. The solvent can be, for example, methanol, ethanol, isopropyl alcohol, acetone, benzene, toluene, etc.
The polymeric substance and the solvent are not limited to those illustrated.
Also, the source material liquid can be produced from a solvent and one type of polymeric substance, or can be produced by mixing a solvent and multiple types of polymeric substances.
Also, the source material liquid that is supplied to the first nozzle head 2a and the source material liquid that is supplied to the second nozzle head 2b may be of the same type; or the source material liquid that is supplied to the first nozzle head 2a and the source material liquid that is supplied to the second nozzle head 2b may be of different types.
The source material liquid is caused to collect at the vicinity of the outlet 20a by surface tension. To this end, the viscosity of the source material liquid can be modified appropriately according to the dimension of the outlet 20a, etc. The viscosity of the source material liquid can be determined by performing experiments and/or simulations. Also, the viscosity of the source material liquid can be controlled by the mixture proportion of the solvent and the polymeric substance.
The supplier 32 supplies the source material liquid stored in the container 31 to the main part 22. The supplier 32 can be, for example, a pump having resistance to the source material liquid, etc. Also, for example, the supplier 32 may feed the source material liquid stored in the container 31 by supplying a gas to the container 31.
The source material liquid controller 33 controls the flow rate, the pressure, etc., of the source material liquid supplied to the main part 22 so that the source material liquid in the interior of the main part 22 is not pushed out from the outlet 20a when new source material liquid is supplied to the interior of the main part 22. In other words, the source material liquid is caused to collect at the vicinity of the outlet 20a by the surface tension. The control amount for the source material liquid controller 33 can be modified appropriately by the dimension of the outlet 20a, the viscosity of the source material liquid, etc. The control amount for the source material liquid controller 33 can be determined by performing experiments and/or simulations.
Also, the source material liquid controller 33 can be able to switch between the starting of the supply and the stopping of the supply of the source material liquid.
The supplier 32 and the source material liquid controller 33 are not always necessary. For example, if the container 31 is provided at a position that is higher than the position of the main part 22, the source material liquid can be supplied to the main part 22 by utilizing gravity. Then, the source material liquid that is in the interior of the main part 22 can be caused not to be pushed out from the outlet 20a when the new source material liquid is supplied to the interior of the main part 22 by appropriately setting the height position of the container 31. In such a case, the height position of the container 31 can be modified appropriately using the dimension of the outlet 20a, the viscosity of the source material liquid, etc. The height position of the container 31 can be determined by performing experiments and/or simulations.
The pipe 34 is provided between the container 31 and the supplier 32, between the supplier 32 and the source material liquid controller 33, and between the source material liquid controller 33 and the main part 22. The pipe 34 is used as a flow channel of the source material liquid. The pipe 34 is formed from a material having resistance to the source material liquid.
The power supply 4 applies the voltage to the nozzle 20 via the main part 22 and the connector 21. Not-illustrated terminals that are electrically connected to the nozzle 20 may be provided. In such a case, the power supply 4 applies the voltage to the nozzle 20 via the not-illustrated terminals. In other words, it is sufficient for the voltage to be able to be applied to the nozzle 20 from the power supply 4.
The polarity of the voltage (the drive voltage) applied to the nozzle 20 can be set to be positive or set to be negative. However, if a negative voltage is applied to the nozzle 20, irregular electric discharge occurs easily because electrons are discharged from the tip of the nozzle 20. Therefore, as shown in
The voltage that is applied to the nozzle 20 can be modified appropriately according to the type of the polymeric substance included in the source material liquid, the distance between the nozzle 20 and the collector 5, etc. For example, the power supply 4 can apply a voltage to the nozzle 20 so that the potential difference between the nozzle 20 and the collector 5 is 10 kV or more. In such a case, if a blade-type nozzle head is used, the voltage that is applied to the nozzle is about 70 kV. On the other hand, if a needle-type nozzle head such as that illustrated in
The power supply 4 can be, for example, a direct current-high voltage power supply. For example, the power supply 4 can output a direct current voltage of not less than 10 kV and not more than 100 kV.
The electrospinning apparatus 1 illustrated in
On the other hand, one each of the source material liquid supplier 3 and the power supply 4 can be provided respectively for the first nozzle head 2a and the second nozzle head 2b. Thus, the control of the supply amount of the source material liquid and/or the control of the applied voltage can be performed respectively for the first nozzle head 2a and the second nozzle head 2b. Therefore, the deposition amount of the fiber 100 at the first surface 5a of the collector 5 and the deposition amount of the fiber 100 at the second surface 5b of the collector 5 can be changed. For example, it is possible to simultaneously form deposited bodies 110 having different thicknesses.
The collector 5 is provided on the side of the nozzle 20 where the source material liquid is discharged. The collector 5 is grounded. A voltage of the reverse polarity of the voltage applied to the nozzle 20 may be applied to the collector 5. The collector 5 can be formed from a conductive material. It is favorable for the material of the collector 5 to be conductive and to have resistance to the source material liquid. The material of the collector 5 can be, for example, stainless steel, etc.
The collector 5 moves in a prescribed direction. The collector 5 illustrated in
Also, the collector 5 may be, for example, a plate-like body moved in the prescribed direction by an industrial robot, etc.
Also, the collector 5 may be, for example, a drum rotating in the prescribed direction.
Also, the collector 5 may be caused to circulate between a roller 51 and a roller 52 as a belt of a belt conveyor.
As shown in
Also, the circulating collector 5 can be multiply provided. In such a case, the multiple collectors 5 can be provided to be arranged in the horizontal direction and can be provided to be arranged in the vertical direction as shown in
Also, the collector 5 may be fed in one direction.
Also, the collector 5 that is fed from the roller 51 to the roller 52 can be multiply provided. In such a case, the multiple collectors 5 can be provided to be arranged in the horizontal direction, and can be provided to be arranged in the vertical direction as shown in
If the collector 5 is set to move in the prescribed direction, a continuous deposition operation is possible. Therefore, the production efficiency of the deposited body 110 made of the fiber 100 can be increased.
The deposited body 110 that is formed on the collector 5 is removed from the collector 5 by a worker. For example, the deposited body 110 is used in a nonwoven cloth, a filter, etc. The applications of the deposited body 110 are not limited to those illustrated.
Also, the collector 5 can be omitted. For example, the deposited body 110 that is made of the fiber 100 also can be directly formed on the surface of a member that is conductive. In such a case, it is sufficient for the member that is conductive to be grounded or for a voltage of the reverse polarity of the voltage applied to the nozzle 20 to be applied to the member that is conductive. Also, it is sufficient for the member that is conductive to be moved in the prescribed direction by using a conveyor, an industrial robot, etc. For example, the configuration of the member that is conductive is not particularly limited and may be a sheet configuration, may be a block configuration, or may be any configuration.
The member that is conductive may be fed in one direction, may be moved back and forth, or may be fed to circulate.
Also, the collector 5 or the member may not move.
The controller 6 controls the operations of the supplier 32, the source material liquid controller 33, the power supply 4, and the collector 5. The controller 6 can be, for example, a computer including a CPU (Central Processing Unit), memory, etc.
Here, in the case where the fibers 100 that are charged with the same polarity are deposited on the first surface 5a and the second surface 5b of the collector 5, there are cases where the fiber 100 deposited on the first surface 5a and the fiber 100 deposited on the second surface 5b repel each other at the vicinity of the end portion of the collector 5.
As shown in
In the electrospinning apparatus 1 described above, the second nozzle head 2b opposes the first nozzle head 2a with the collector 5 interposed. In other words, when viewed in plan, the second nozzle head 2b is provided at a position overlapping the first nozzle head 2a.
Conversely, in the electrospinning apparatus 1a according to the embodiment, the second nozzle head 2b is provided at a position that is separated from the first nozzle head 2a in the movement direction 50 of the collector 5. For example, the second nozzle head 2b is provided at a position that is shifted in the movement direction 50 of the collector 5 from the position where the first nozzle head 2a is provided. In other words, when viewed in plan, the second nozzle head 2b does not overlap the first nozzle head 2a. In such a case, a distance L between the first nozzle head 2a and the second nozzle head 2b can be set to be longer than the longer dimension of the dimension of the deposition region on the first surface 5a of the fiber 100 discharged from the first nozzle head 2a or the dimension of the deposition region on the second surface 5b of the fiber 100 discharged from the second nozzle head 2b. Thus, the repulsion between the fiber 100 deposited on the first surface 5a and the fiber 100 deposited on the second surface 5b at the vicinity of the end portions of the collector 5 can be suppressed. Therefore, the deposited body 110 can be formed on the entire region of the first surface 5a and the second surface 5b. Also, the fluctuation of the thickness and/or the width dimension of the deposited body 110 can be suppressed. Also, the utilization efficiency of the source material liquid can be increased; and the occurrence of the soiling due to the fibers 100 adhering to the interior of the electrospinning apparatus 1a can be suppressed.
When viewed in plan, the distance L is the distance between the first nozzle head 2a and the second nozzle head 2b.
As shown in
Also, in the case where a width dimension W (a dimension in a direction orthogonal to the movement direction 50) of the collector 5 is long, the multiple first nozzle heads 2a can be provided to be arranged in the width direction of the collector 5 as shown in
In such a case, there is a risk that the fibers 100 deposited on the first surface 5a may repel each other in the region between the first nozzle heads 2a if the multiple first nozzle heads 2a are provided to be proximal in the width direction of the collector 5. There is a risk that the fibers 100 deposited on the second surface 5b may repel each other in the region between the second nozzle heads 2b if the multiple second nozzle heads 2b are provided to be proximal in the width direction of the collector 5.
Therefore, one of the first nozzle heads 2a is provided at a position separated from an adjacent other first nozzle head 2a in a direction orthogonal to the movement direction 50 of the collector 5. In other words, the adjacent other first nozzle head 2a is provided at a position shifted in the direction orthogonal to the movement direction 50 of the collector 5. One of the second nozzle heads 2b is provided at a position separated from an adjacent second nozzle head 2b in the direction orthogonal to the movement direction 50 of the collector 5. In other words, the adjacent second nozzle head 2b is provided at a position shifted in the direction orthogonal to the movement direction 50 of the collector 5.
For example, as shown in
Also, to suppress the repulsion between the fiber 100 deposited on the first surface 5a and the fiber 100 deposited on the second surface 5b at the vicinity of the end portions of the collector 5, the multiple second nozzle heads 2b can be provided to not overlap the multiple first nozzle heads 2a when viewed in plan.
Also, in the case where the width dimension W of the collector 5 is short as shown in
The direction in which the second nozzle head 2b extends can be set to be parallel to the movement direction 50 of the collector 5. Also, the multiple second nozzle heads 2b can be provided to be arranged in the width direction of the collector 5. Also, to suppress the fibers 100 deposited on the second surface 5b repelling each other in the region between the second nozzle heads 2b, one of the second nozzle heads 2b is provided at a position separated from an adjacent second nozzle head 2b in the direction orthogonal to the movement direction 50 of the collector 5. In other words, the adjacent second nozzle head 2b is provided at a position shifted in the direction orthogonal to the movement direction 50 of the collector 5.
As shown in
An angle θb between the direction in which the second nozzle head 2b1 extends and the movement direction 50 of the collector 5 can be changed. In other words, the angle θb between the direction in which the second nozzle head 2b extends and the movement direction 50 of the collector 5 is changeable for the second nozzle head 2b.
For example, it is sufficient to provide one end portion of a shaft perpendicular to the first surface 5a of the collector 5 at the main part 22 of the first nozzle head 2a and to provide a holder that rotatably holds the shaft. It is sufficient to provide one end portion of a shaft perpendicular to the second surface 5b of the collector 5 at the main part 22 of the second nozzle head 2b and to provide a holder that rotatably holds the shaft.
Thus, by appropriately modifying the angle θa, the deposited bodies 110 that have different width dimensions in the first surface 5a can be formed easily. By appropriately modifying the angle θb, the deposited bodies 110 that have different width dimensions in the second surface 5b can be formed easily.
Also, collectors 5 that have different width dimensions W can be accommodated easily.
Effects of the electrospinning apparatuses 1 and 1a will now be described.
The source material liquid collects at the vicinity of the outlet 20a of the nozzle 20 due to surface tension.
The power supply 4 applies the voltage to the nozzle 20. Then, the source material liquid that is at the vicinity of the outlet 20a is charged with a prescribed polarity. In the case of the electrospinning apparatuses 1 and 1a illustrated in
An electric field is generated between the nozzle 20 and the collector 5 because the collector 5 is grounded. Then, when the electrostatic force acting along the lines of electric force becomes larger than the surface tension, the source material liquid that is at the vicinity of the outlet 20a is drawn out toward the collector 5 by the electrostatic force. The source material liquid that is drawn out is elongated; and the fiber 100 is formed by the volatilization of the solvent included in the source material liquid. The fiber 100 that is formed is deposited on the first surface 5a and the second surface 5b of the collector 5 to form the deposited body 110 on the first surface 5a and the second surface 5b.
Also, in the case of the electrospinning apparatus 1a, the repulsion between the fiber 100 deposited on the first surface 5a and the fiber 100 deposited on the second surface 5b at the vicinity of the end portions of the collector 5 can be suppressed. Therefore, the deposited body 110 can be formed on the entire region of the first surface 5a and the second surface 5b. Also, the fluctuation of the thickness and/or the width dimension of the deposited body 110 can be suppressed. Also, the utilization efficiency of the source material liquid can be increased; and the occurrence of soiling due to the fiber 100 adhering to the interior of the electrospinning apparatus 1a can be suppressed.
While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the invention. Moreover, above-mentioned embodiments can be combined mutually and can be carried out.
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Entry |
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Number | Date | Country | |
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20180202074 A1 | Jul 2018 | US |
Number | Date | Country | |
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Parent | PCT/JP2017/032478 | Sep 2017 | US |
Child | 15919503 | US |