JP5475646B2 - Electrospinning apparatus, fiber structure manufacturing method, and electrospun fiber structure - Google Patents

Description

The present invention relates to a fibrous structure, and a process and apparatus for manufacturing the same. In particular, the present invention relates to methods and systems for electrospinning fiber structures, for example products such as nanofiber structures and their use. The invention also relates to the field of wound dressings. In particular, the present invention relates to a method and system for controlling the amount of liquid near the surface, such as applied to a wound dressing. The invention also applies to the dental field. In particular, the present invention relates to a method, production and system for application to tooth bleaching.

Nanofiber structures can be used in a variety of fields such as clothing, filters, medicine and protection. There is a strong interest in nanofiber structures based on high porosity for absorption, immobilization and encapsulation of chemicals, solvents, solutions, melts and liquids. High absorption is preferred in many applications, and an absorbency of about 5 ml / cm 2 is desirable. For the same application, a large nanofiber structure is preferred. A uniform thickness is good across the entire structure to ensure absorption across the structure. Furthermore, the application of nanofiber structures in filters requires a strong structure. The nanofiber structure is manufactured using an electrospinning apparatus. A typical device is shown in FIG. 1, which comprises a power source 1, an anesthetic pump 2 and a syringe 3 that constitutes a pump containing a polymer solution 4. The pump delivers the polymer solution to the tip of the metal needle 5. The needle is placed on a spinneret 6, which comprises an upper 7 and a lower 8 conductive plate. An electric field can be applied to the upper and lower plates to push the polymer solution from the needle tip to the surface of the lower component. The generated electric field creates a force in the polymer solution that exceeds the cohesive forces that hold the polymer solutions together. As a result of the cohesive force compensation by the electric field, a jet is blown out of the polymer solution, thereby forming nano-order fibers and finally collected on the lower plate. A typical dimension of the deposited structure is a circular surface having a diameter of about 10-15 cm. Therefore, in the case of a single nozzle system, a wide surface area required for many applications can be obtained economically inexpensively.

US 2002/0175449 discloses an apparatus and method for electrospun polymer fibers and thin films. The method includes controlling the electric field strength at the tip of the spinneret by adjusting the charge to provide a controlled diameter fiber. By changing the electric field, the acceleration of the jet stream is changed, resulting in a change in the diameter of the nanofiber formed. The change in the electric field changes the stability of the jet stream, and the corresponding change at the composite electrode stabilizes the new jet stream. The distance between two adjacent spinnerets changes the electric field so as to optimize the electric field, i.e. individual spinnerets do not influence each other. One application of a nanofiber structure is a wound dressing device. Wound dressings can be applied to many types of injuries such as cuts, lacerations, abrasions, stabs, burns and the like.

  For wound dressings, gauze-based bandages or sticky vantages such as zinc paste vantages are originally used. Many modern wound dressing devices have important properties, such as having humidity retention and absorption functions, or humidity retention and antibacterial functions. In particular, in the case of burns, exudate from the wound is a major problem. Many techniques used to treat such wounds dry the wound as much as possible, thereby preventing infection and accelerating healing. However, an overview has shown that in the case of a particular wound, it is preferable to keep the leachate near the wound. This is because molecules and coagulation substances that are important in the wound healing process are present in the exudate.

  Several commercially available wound dressing devices have been released. One category of wound dressing devices is based on the use of electrospun materials. U.S. Pat. No. 4,878,908 discloses a wound covering having a woven fabric support, an adhesive surface provided at the end, and a pad of absorbent material covered by a mat of electrospun material. An example device is disclosed. However, there is room for improvement of the wound dressing device.

  One aspect of the invention relates to tooth bleaching. There are two main aesthetic use cases known for tooth bleaching, one for use in the dental industry and the other for use outside the dental industry, for example by the customer at home or other suitable location. An example. Some of these solutions require several visits to the dentist.

  Solutions that include use cases that can be performed outside the dental clinic use trays that are made to fit the user's mouth and teeth. The tray is made in the dental industry but can be used at home. The typical example of such a device requires cost reuse and is robust enough to allow repeated handling, cleaning, filling, mounting, removal, etc. I need it.

  Low cost solutions have also been proposed. There, a free size method is used. These systems are often not fully compatible with the teeth and increase the amount of bleach supplied. Moreover, in such a system, there is a problem that the bleaching agent may leak into the gums and be taken into the body.

  US Patent Application Publication No. 2005/0196352 A1 by Procter & Gamble Company discloses a method that includes applying a system for delivering tooth bleach to a plurality of adjacent teeth. The tooth bleach delivery system has a piece of material and a tooth bleach containing peroxide. The method includes attaching a first piece of material to the facial surface of a tooth, folding a second piece of material near the edges of a plurality of adjacent teeth, and a piece of covering the edges. Folding the second part to attach the second part of the material to the lingual side of the tooth.

  It is an object of the present invention to provide an innovative apparatus or method for producing fiber (eg, nanofiber) structures.

An advantage of embodiments according to the present invention, according to the dimensions of the electrospun fiber structure (electrospun fibrous structure), and it can produce fiber structure formed by (e.g., decreasing) fiber diameter variously changed, There are methods and apparatus for producing them. A preferred embodiment according to the present invention resides in a method and system for providing a nanofiber structure with a rigid structure. That is, in the nanofiber structure, decomposition / strain or delamination hardly occurs or does not cause a problem during normal use. A preferred embodiment of the present invention is a method and system for providing a strong, porous, and / or renewable nanofiber structure. A further preferred embodiment of the present invention is a method for providing and producing a fibrous structure with excellent liquid absorbency.

  A preferred embodiment of the present invention is a method for providing and producing fiber structures with excellent controlled release and filtration properties. The preferred embodiment of the present invention provides an economically feasible method. In a preferred embodiment according to the present invention, a fiber structure having characteristics combining two or more of the above-described preferred embodiments can be produced. In a preferred embodiment of the present invention, a laminated structure is made. In a preferred embodiment according to the present invention, superior overlap is achieved using different nozzle movements according to the controller. The above objective is accomplished by the method and apparatus of the present invention.

The present invention relates to an electrospinning apparatus for producing a fiber structure. The electrospinning apparatus includes a set of discharge portions for discharging a solution or a melt and a receiving surface for receiving discharge from the set of discharge portions, and the receiving surface includes the receiving surface. And the movement corresponds to forming a length of the fiber structure, and the electronic rotating device includes the one set of discharge portions and A power source for generating a potential difference between the receiving surface and the electrospinning device during production of the fiber structure in order to achieve a predetermined fiber thickness profile across the fiber structure; The distance between the discharge part of the device and the receiving surface varies according to a predetermined profile. Such a change according to a predetermined distance profile is pre-defined for the distance between the discharge part and the receiving surface in a direction perpendicular to the receiving surface for different discharge parts along the first direction. This is realized by a predetermined distance profile. The predetermined distance profile is to increase the distance profile or decrease the distance profile. The predetermined distance profile is to monotonically increase the distance profile or monotonically decrease the distance profile.

In a preferred implementation according to the invention, there is provided an apparatus capable of producing a fiber structure comprising fibers, wherein the diameter of the fibers decreases along the dimensions of the electrospun fiber structure and is perpendicular to the dimensions. The local difference in fibers in any part is at a predetermined level, for example less than 10%. In an embodiment of the present invention, the diameter of the fiber monotonously decreases along the dimension of the electrospun fiber structure. In other embodiments of the invention, the fiber diameter follows a predetermined diameter profile along the dimension of the electrospun fiber structure. For example, the fiber diameter decreases monotonically or continuously along the dimensional direction of the electrospun fiber structure.

  In an embodiment of the present invention, the set of discharge portions includes a subset of the discharge portions, and each of the set of discharge portions is equidistant from the receiving surface. The distance between each subset and the receiving surface varies along the length direction in which the fibrous structure grows according to a predetermined distance profile. In a preferred embodiment of the present invention, a layer structure including two or more adjacent layers may be formed. Each layer having two adjacent layers has an average diameter that is smaller than the average diameter of the fibers of one adjacent layer and an average diameter that is larger than the average diameter of the fibers of the adjacent layer.

  In the embodiment of the present invention, the set of discharge portions is provided on a predetermined surface inclined at a predetermined angle with respect to the receiving surface. Preferably, the fiber structure comprising fibers is such that the diameter of the fibers can be continuously reduced along the dimensional direction of the fiber structure.

According to an embodiment of the present invention, during the electrospinning process, the distance of the nozzle to the collector changes and may be combined with a change in distance before and / or after that process as appropriate.

  In an embodiment of the present invention, at least two adjacent discharge portions of the set of discharge portions are separated from each other by a distance of at least 1 cm. In a preferred embodiment according to the present invention, the device is provided so that a highly porous fiber structure can be produced. At least two adjacent discharge portions of the set of discharge portions are separated from each other by a distance of at least 1 cm. More preferably, two adjacent drains are separated by a distance of at least 4 cm, and more preferably are separated by a distance of at least 8 cm. Each two discharge parts of the set of discharge parts are separated from each other by a distance of at least 1 cm, preferably a distance of 4 cm, more preferably a distance of 6 cm. In other words, there is at least one discharge (e.g., nozzle) that is at least 1 cm, preferably at least 4 cm, and more preferably at least 6 cm to the nearest other discharge. Most or all of the discharges may be separated from other discharges by a distance of at least 1 cm, preferably a distance of 4 cm, more preferably a distance of 6 cm. In a preferred embodiment according to the present invention, the device is provided such that it is strong, highly porous, and capable of producing a fiber structure comprising linear fibers. As an appropriate feature, the discharge part (for example, nozzle) is arranged so as to form a triangle or a polygon.

  In an embodiment of the invention, the distance between the discharges is provided so that a fiber structure can be produced that contains at least 50% of fibers that are substantially cross-bonded to adjacent fibers. In a preferred embodiment according to the present invention, the device is provided so that it can produce a fiber structure that includes only cross bonds at small angles.

  In an embodiment of the invention, the distance between the discharge sections is provided so as to produce a fiber structure containing at least 50% linear fibers.

The apparatus may comprise control means for changing the diameter of the produced fiber substantially during the electrospinning process.

  In an embodiment of the invention, the means for changing the diameter of the produced fiber is for changing the distance between the first plane and the receiving surface during or otherwise producing the fiber structure. It may be a control means. As a feature provided as appropriate, the lower part and the upper part are provided so as to be movable in the vertical direction.

  In an embodiment of the invention, the device is provided to produce a plurality of fibers. In that case, at least 50% of the plurality of fibers have an average diameter between 3 and 2000 nm.

  In an embodiment of the present invention, the apparatus comprises polyamide, polystyrene, polycaprolactone, polyacrylonitrile, polyethylene oxide, polylactic acid, polyacrylic acid, polyesteramide, polyvinyl alcohol, polyimide, polyurethane, polyvinylpyrrolidone, collagen, polyethylene It is provided to use a polymer solution comprising at least one of co-vinyl acetate, alcohol, collagen, chitosan, methacrylic resin, silk, and metal.

  The invention also relates to a method for producing a fibrous structure. The method includes providing a set of discharges for discharging a solution or melt, providing a receiving surface for receiving discharge from the set of discharges, and the receiving surface. Moving the receiving surface in a first direction parallel to the step, providing a potential difference between the set of discharge portions and the receiving surface, and moving the solution and providing a potential difference. Or providing a melt to the drain, and providing a predetermined thickness profile while providing the solution or melt to the drain to provide a drain according to the predetermined profile. The distance between and the receiving surface changes. Such a predetermined profile is brought about by a change in the distance between the discharge part and the receiving surface in a direction perpendicular to the discharge surface of the discharge part along the growth direction of the length of the fiber structure, Alternatively, this is caused by a virtual relative movement of the set of discharges relative to the receiving surface. The predetermined distance profile is to increase the distance profile or to decrease the distance profile, for example to monotonically increase the distance profile or monotonically decrease the distance profile. At least two adjacent drains of the two or more drains are separated by a distance of at least 1 cm, preferably at least 4 cm, more preferably at least 6 cm. Each two of the set of drains are separated from each other by a distance of at least 1 cm, preferably at least 4 cm, more preferably at least 6 cm.

  The change in the distance between the discharge part and the receiving surface is suitably obtained by applying the distance between the adjacent discharge part and the receiving surface during the production of the fiber structure. The distance is provided by providing relative movement between the set of discharges and the receiving surface. As a preferred optional feature, the method further comprises reciprocating at least one of the set of discharges and / or the receiving surface in a direction parallel to the receiving surface and perpendicular to the first direction. . The method may be provided to produce a plurality of fibers, in which case at least 50% of the plurality of fibers have an average diameter between 3 and 2000 nm.

  The methods are polyamide, polystyrene, polycaprolactone, polyacrylonitrile, polyethylene oxide, polylactic acid, polyacrylic acid, polyester amide, polyvinyl alcohol, polyimide, polyurethane, polyvinyl pyrrolidone, collagen, polyethylene co-vinyl acetate, alcohol, It is provided to use a polymer solution or melt containing at least one of collagen, chitosan, methacrylic resin, silk, and metal.

  As a feature provided as appropriate, a potential difference between 100 V and 200,000 V is provided between the pair of discharge portions and the receiving surface. Another feature provided as appropriate is that the pump speed of the polymer solution or melt per discharge is between 0.01 and 500 nl / h.

  As an optional feature, the solution or melt may contain additional substances such as antibacterial substances, drugs, hydrophobic / hydrophilic substances, anti-corrosive substances, catalysts, oxidizing / reducing agents and other substances. .

The present invention also relates to an electrospun fiber structure manufactured using the method according to the above-described embodiment of the present invention.

The invention also relates to an electrospun fiber structure comprising fibers. The fiber diameter varies along the dimension of the electrospun fiber structure according to a predetermined fiber diameter profile, and the fiber diameter change is less than 10% in any part perpendicular to the dimension direction. .

  In an embodiment of the invention, the structure comprises at least 50% linear fibers. At least 50% of the linear fibers have a substantially linear portion of 5 μm or more.

The electrospun fiber structure includes at least 50% fibers that are substantially non-cross-linked to adjacent fibers. The electrospun fiber structure includes at least 50% randomly oriented fibers. The electrospun fiber structure has a porosity of at least 65%. More than 50% of the fibers have an average diameter between 3 and 2000 nm, preferably more than 10 nm, preferably less than 700 nm.

The present invention also relates to an electrospun fiber structure having two or more layers. Each of the layers consists of fibers having an average diameter that is different from the average diameter of the fibers of the adjacent layers. In an embodiment of the invention, the fibrous structure has two or more adjacent layers, each layer having two adjacent layers being made of fibers having an average diameter of a predetermined dimension. The predetermined average diameter may be larger or smaller than the average diameter of the fibers of the adjacent layer. In certain embodiments, the average diameter of the fibers is smaller than the average diameter of the fibers in one adjacent layer and larger than the average diameter of the fibers in the other adjacent layer. The diameter decreases, for example, as a function of depth, increases as a function of depth, increases after initially decreasing as a function of depth, decreases after increasing initially as a function of depth, and so forth.

  It is also an object of the present invention to provide an excellent apparatus or method for controlling liquid near the wound, such as exudate. In a preferred embodiment according to the present invention, the amount and flow of liquid can be controlled. In a preferred embodiment of the present invention, a controlled amount and possibly a large amount of exudate may be absorbed. Preferred embodiments according to the present invention can achieve superior control of fluid transfer to and / or from the wound via the contact surface of the wound dressing device. Such transmission is in the direction of the area different from the wound or in the area of contact with the surface of the wound dressing. In a preferred embodiment according to the present invention, fluid release control is realized, for example, on the opposite side of the contact surface of the wound dressing device. In a preferred embodiment, the wound fluid is absorbed but may be retained near the wound or released back toward the wound if the particular structure of the embodiment is used. Good. In a preferred embodiment according to the present invention, the amount of exudate removed from the wound by the wound dressing device may be controlled so that there is a controlled amount of exudate near the wound.

  The above object is achieved by the method and apparatus according to the embodiments of the present invention.

  The invention also relates to a wound dressing device for controlling fluid near a wound. The wound dressing device includes a nanofiber structure that includes a plurality of fibers. The nanofiber structure has a contact surface for contacting the wound. In order to control absorption and / or release from the wound, the fiber diameter of the nanofiber structure changes in a direction perpendicular to the contact surface. In a preferred embodiment according to the present invention, controlled liquid absorption can be achieved. In a preferred embodiment according to the present invention, the absorption of many liquids is realized. In a preferred embodiment, a controlled amount of liquid is absorbed and the absorbed liquid is released on the other side of the wound covering to return to the wound or released back to the wound.

  The wound dressing device has fibers having a diameter smaller than the diameter of the fibers on the contact surface and smaller than the diameter of the fibers on the opposite surface of the contact surface at an intermediate position in a direction perpendicular to the contact surface. Preferably, a predetermined profile of liquid absorption and / or release from or to the wound is achieved.

  The fiber diameter may decrease from the contact surface to the surface of the nanofiber structure opposite the contact surface. In preferred embodiments of the invention, dynamic flow of fluid from the contact surface to other surfaces may be established. In a preferred embodiment according to the present invention, the wound considered as the liquid discharge surface may be kept substantially dry. Alternatively, or in addition, a controlled amount of liquid may be retained at or near the wound, which is desirable for healing. In a preferred embodiment according to the invention, the most effective evaporation characteristic is obtained on the opposite side of the contact surface from which the highest specific surface area is obtained. The opposite side of the contact surface functions as a liquid discharge side. Alternatively or in addition, release may be controlled to return to the wound.

  The fiber diameter may follow another relationship that decreases from the contact surface, minimizing at the center of the structure and increasing from the center of the surface of the nanofiber structure opposite the contact surface. By using such a structure, it is possible to absorb the liquid from the wound and not return the liquid toward the wound. The fluid is balanced at the wound, which is desirable for wound healing as described above.

  The nanofiber structure may be a laminated nanofiber structure comprising at least two layers of nanofibers having different diameters.

  The wound dressing device includes at least one nanofiber intermediate layer, which layer is disposed between other layers of nanofibers of the wound dressing device. In that case, the at least one intermediate layer comprises nanofibers having a diameter smaller than the diameter of the nanofibers of the other layers.

The fiber structure may be electrospun . In a preferred embodiment according to the present invention, the wound dressing device is made in an efficient manner.

  The nanofiber structure has an average porosity between 65% and 99%, preferably between 70% and 98%, more preferably between 75% and 95%. In a preferred embodiment according to the present invention, high absorption performance can be realized. The ability to absorb liquid is between 1 g and 25 g per gram of polymer, preferably between 10 g and 25 g per gram of polymer.

  The nanofiber structure may further include a gel material. In a preferred embodiment according to the present invention, the absorbent performance of the wound dressing device can increase liquid absorption to 70 g / g polymer.

A gel-forming material is provided to coat individual nanofibers. The gel-forming material is provided to the wound dressing device by electrospinning it in the nanofiber.

  The nanofiber structure has at least a portion having a pore diameter of less than 150 nm in order to function as a bacterial barrier. In a preferred embodiment according to the present invention, the bacterial barrier is formed for the wound by the pore size of the nanofiber structure which is smaller than typical bacteria.

  The nanofiber layer comprises a liquid transmission barrier on at least a portion of the nanofiber layer on the side of the contact surface. The liquid transmission barrier prevents liquid from flowing laterally beyond the contact surface. With lateral flow, there is an intended flow in a direction in the plane of the contact surface.

  In a preferred embodiment of the present invention, the flow of fluid from one wound to another can be reduced, moderated or even eliminated, thus reducing cross-infection between adjacent wounds. it can. The liquid transfer barrier distributes the contact surface of the nanofiber structure in a plurality of small, discrete, separated nanofiber regions and prevents liquid flow near the contact surface between adjacent regions. It may be provided. The liquid transmission barrier includes melted nanofibers and / or nanofibers that stick together. The liquid transmission barrier extends only part of the depth in a direction perpendicular to the contact surface.

  In a preferred embodiment according to the present invention, firstly, exudate is prevented from flowing to an adjacent wound area. Secondly, effective evaporation is supported by a partial spread of moisture on the opposite side of the contact surface. Third, exudate is retained in the nanofiber structure for release to the wound if necessary for wound healing. The nanofiber layer may include a liquid transmission barrier to retain the liquid in the nanofiber structure and later release it to the wound.

  The nanofiber structure further comprises nanofibers comprising a bactericidal material. The nanofibers are provided near the contact surface of the wound dressing device. Nanofibers containing a sterilizing material may dissolve in the liquid absorbed by the nanofiber structure and exhibit the bactericidal, antibacterial and / or biocidal properties of the device. In a preferred embodiment according to the present invention, antibacterial and / or biocidal properties may be provided in the wound dressing device, thereby providing a separate product for producing antibacterial and / or biocidal properties. No need to use.

  Nanofibers containing a sterilizing formulation amount may include isobetadine (R) nanofibers. Isobetadine (R) fibers (fibers) are produced by rotating the PVP-I solution electronically. The wound dressing device can absorb 1 to 25 g of liquid per gram of nanofiber structure when the liquid has a concentration of 1 kg / l. In the case of a liquid having a concentration of 1 kg / l, the wound dressing device has the ability to absorb 3 to 25 times, preferably 4 to 25 times, and more preferably 5 to 25 times its own weight.

  The device is suitable for covering large scratches or large scratches, and the nanofiber structure has a 30 cm square, preferably 40 cm square, more preferably 50 cm square contact surface. Other devices are suitable for very small wounds and have a size smaller than 2 cm square or smaller than 5 mm square. The nanofiber structure may have a thickness of 50 μm to 5000 μm.

  The wound dressing device can be cut into any shape by hand or machine using mechanical, thermal, or laser cutting.

  The nanofiber structure may be provided on an adhesive substrate for attachment to the skin around the wound. At least 30%, preferably at least 50%, of the nanofibers of the nanofiber structure have an average diameter of 3 to 2000 nm.

  The nanofiber structure comprises at least 50% linear fibers, at least the fibers having a substantially straight portion that exceeds a length of 5 μm. The nanofiber structure may comprise at least 50% randomly oriented fibers.

  The invention also relates to the use of a wound dressing device as described above for a wound dressing.

  The invention further relates to a method for a wound dressing device. The method includes producing a nanofiber structure having a contact surface that contacts a wound, the diameter of the fiber (fiber) changing in a direction perpendicular to the contact surface according to a predetermined profile. The method also includes positioning the nanofiber structure in a predetermined direction by contacting the nanofiber structure with a wound. In a preferred embodiment according to the present invention, oxygen is permeable through the wound dressing device, i.e. the nanofiber structure. This can promote healing of the wound.

  It is also an object of the present invention to provide an excellent method and system for tooth bleaching (also referred to as tooth bleaching). In a preferred embodiment according to the present invention, the method and system allows accurate delivery to the tooth bleaching section or its components. In a preferred embodiment according to the invention, there is little or no leakage to the mouth area around the teeth.

  In a preferred embodiment according to the present invention, the tooth bleaching section or its components are delivered to the canine.

  In a preferred embodiment according to the present invention, it is possible to stably place and / or fix the device on the user's teeth. In a preferred embodiment according to the present invention, the method and system require very little component or characteristic property of the bleaching part to secure the device to the tooth. For example, it is not necessary to fix the components to the tooth bleaching part. In a preferred embodiment according to the present invention, the method and system allows for the use of low viscosity tooth bleaching, thus allowing more effective tooth bleaching.

  In a preferred embodiment according to the present invention, the device can provide excellent compatibility and can also cover canines. In a preferred embodiment according to the invention, the teeth are bleached relatively smoothly and / or uniformly. In a preferred embodiment according to the present invention, it is possible to bleach the front teeth array including canines accurately and substantially uniformly. In a preferred embodiment according to the invention, the tip of the canine is also covered and thereby bleached. In a preferred embodiment according to the invention, an excellent movement of the tooth bleaching part is possible through the device. In a preferred embodiment according to the present invention, the folds of the fiber structure can be eliminated and a better fit is possible. The folded shape on the teeth is maintained during use of the device. By eliminating the crease, the movement of the tooth bleaching part or its constituent elements can be suppressed. In a preferred embodiment of the present invention, the structure is well adapted due to the fiber structure of the device.

  According to a preferred embodiment of the present invention, water can be permeated and absorption of a tooth bleaching part can be supported. In a preferred embodiment according to the present invention, the fiber structure varies the fiber diameter as a function of depth in the fiber structure in order to control the release profile of the tooth bleaching section. The above objective is accomplished by a method and apparatus according to preferred embodiments of the present invention.

  The present invention relates to a tooth bleaching system for bleaching teeth. The tooth bleaching system comprises a nanofiber structure and a tooth bleaching section containing a bleaching agent. In a preferred embodiment of the present invention, the method and system can accurately deliver the tooth bleaching section or its components. In a preferred embodiment of the present invention, the method and system result in little or no leakage into the mouth area around the teeth. In the preferred use of the nanofiber structure, the system can be applied to the teeth and maintains an excellent fit to the teeth.

  The tooth bleaching part has a viscosity of 10 cps to 1000 cps, preferably 10 cps to 400 cps, more preferably 10 cps to 199 cps. In a preferred embodiment according to the present invention, a method and system is provided in which the tooth bleaching portion is relatively low viscosity due to the fluid absorption and release characteristics according to the present invention. In an excellent embodiment according to the present invention, a low viscosity gel may be used for dental bleaching applications, in which case the gel is retained in the system by the nanofiber structure. In a preferred embodiment according to the present invention, the risk of leaking into, for example, gingiva in the mouth or structures on the palate is limited, reduced or eliminated.

  The tooth bleaching part may be a tooth bleaching gel. In that case, the tooth bleaching gel further comprises a gel-forming material. In a preferred embodiment according to the present invention, the use of gel reduces or eliminates the occurrence of leakage. This improves user comfort. For example, it reduces irritation to a part of the mouth around the teeth.

  The concentration of the gel-forming material is less than 0.1 percent by weight of the bleaching member, for example 0.09 percent by weight.

  The gel-forming material may include carboxymethylcellulose, carboxypropylcellulose, gum, poloxamer, carboxyoxide polymethylene. In a preferred embodiment according to the present invention, a low concentration of gel forming material is used such that the viscosity of the bleaching section is reduced due to the presence of nanofiber structures.

  The nanofiber structure of the system may be provided to adapt to the front tooth row. In a preferred embodiment according to the present invention, the nanofiber structure may be provided to be adapted to a set of teeth.

  The nanofiber structure of the system is provided to be compatible with incisors and canines (including canine tips). The incisors are the upper four front teeth or the lower four front teeth. In a preferred embodiment according to the present invention, the canine is often yellowed, and the canine adjacent to the incisor may be bleached because the canine and the incisor are made uniform by bleaching the canine. Thereby, the contrast between the canine and the incisor is reduced.

  The nanofiber structure can be compressed to a thickness between 100 nm and 10 mm. In a preferred embodiment according to the present invention, it is compatible not only with canines but also with incisors by using compressed nanofiber structures suitable for teeth. In a preferred embodiment according to the present invention, the device or at least the fiber structure thereof is pressed against the teeth by compressing the device or at least compressing the fiber structure thereof, whereby the device or at least of them The fiber structure conforms to the shape of the teeth.

  The nanofiber structure has a thickness of 1 μm to 5000 μm, preferably 1 μm to 2000 μm.

  The structure of the nanofiber structure is applied so that the system on the tooth surface sticks. In a preferred embodiment according to the present invention, no additional components or properties are required in the tooth bleaching section in order to adhere to the tooth surface.

  The nanofiber structure has an average porosity of 65% to 99%, preferably 70 to 98%, more preferably 75 to 95%. In a preferred embodiment according to the present invention, the porosity of the nanofiber structure is provided so as to influence such stickiness. The system may be provided such that it is secured to the front of the tooth using the first part and secured to the back of the tooth using the second part.

  The nanofiber structure may have different porosities across the cross-section for controlled delivery of bleach to the teeth. The nanofiber structure has a predetermined variation profile of porosity in its cross-section to achieve a predetermined release profile that releases bleach to the teeth. In a preferred embodiment according to the present invention, the bleaching agent can be controlled to assist in uniformly affecting the treatment.

  The porosity of the nanofiber structure may increase from the side that contacts the substrate layer to the side that contacts the tooth surface. The nanofiber structure may be a laminated nanofiber structure comprising at least two layers of nanofibers having different diameters.

  The tooth bleaching system includes a base layer for supporting the nanofiber structure, the base layer being substantially waterproof and water insoluble. In a preferred embodiment according to the invention, the substrate allows the system on the tooth to better fit. In a preferred embodiment according to the present invention, the substrate provides a barrier against leakage of bleaching parts, for example to the gingival area and / or the tongue.

  The nanofiber structure includes fibers that include a pH adjusting material. In a preferred embodiment according to the present invention, at least a portion of the pH adjusting material is kept isolated from the bleach prior to use or preparation of the system for use. This makes it possible to increase the influence of the bleaching agent during use or to increase the product life of the system. In a preferred embodiment of the present invention, a pH adjusting material is further included in the nanofiber structure, thereby eliminating the need to provide additional components for isolation and storage prior to use.

  The tooth bleaching part may contain a pH adjusting substance. The pH adjusting substance may include any one of sodium hydroxide, hydrogen chloride, sodium phosphate, sodium bicarbonate, sodium stannate, citric acid, and sodium citrate, or a combination thereof. The pH adjusting substance of the tooth bleaching part may be between 0.1 important percent and 10 weight percent.

  The concentration of the bleaching agent may be 0.1 to 25 weight percent of the tooth bleaching portion, preferably 0.5 to 10 weight percent of the tooth bleaching portion, more preferably 1 to 7 weight percent of the tooth bleaching portion. The bleaching agent may be any one or combination of peroxides and peroxide-generating compounds. The peroxide is, for example, hydrogen peroxide or calcium peroxide. The peroxide-generating compound is a percarbonate such as carbamide peroxide, perborate or peroxy acid. Suitable bleaching materials for use are hydrogen peroxide, carbamide peroxide, or mixtures thereof. Hydrogen peroxide is very effective.

  The tooth bleaching part may further comprise a filling mixture. The filling mixture includes glycerin, sorbitol, polyethylene glycol, or polypropylene glycol. Of the nanofiber structure, at least 30%, preferably at least 50% of the nanofibers have a diameter of 3 to 2000 nm.

  The nanofiber structure comprises at least 50% linear fibers longer than at least 5 μm. The nanofiber structure includes at least 50% randomly oriented fibers.

The nanofiber structure may be an electrospun nanofiber structure.

  When applying the system over 2 to 30 minute teeth twice a day between 5 and 14 days, a minimum 1 to maximum 14 shade change bleaching effect can be obtained with respect to the shade change history scale. . The embodiment according to the present invention provides an excellent bleaching effect.

  The tooth bleaching system (whitening system) may be a kit that separates and holds the nanofiber structure and the tooth bleaching part during storage before use. The kit may further include a tray for immersing the nanofiber structure in the tooth bleaching section when starting to use the tooth bleaching system.

The nanofiber structure may include fibers made from polyamide produced by electrospinning using a compound of formic acid and acetic acid. The ratio of formic acid and acetic acid may be between 90 and 10 to 10 and 90, preferably between 30 and 70 to 70 and 30, and more preferably between 40 and 60 to 60 and 40, respectively, by weight. It may be 50 to 50 in weight percent ratio.

  The invention also relates to the use of a tooth bleaching system as described above for tooth bleaching.

  The present invention also relates to nanofiber structures, which are used for tooth bleaching (whitening) applications.

  The nanofiber structure may be applied in a series of front teeth.

  The nanofiber structure of the system may be adapted to incisors and canines. The canine includes its tip.

  The nanofiber structure can be compressed to a thickness of 100 nm to 5 mm.

  The nanofiber structure has a thickness between 1 μm and 5000 μm, preferably between 1 μm and 2000 μm. The structure of the nanofiber structure may be provided so that the system adheres on the complementary surface.

  The nanofiber structure has an average porosity of 65 to 99%, preferably 70 to 98%, more preferably 75 to 95%.

  The system may be adapted to be secured to the front surface of the tooth using a first portion and to be secured to the back surface of the tooth using a second portion.

  The nanofiber structure may vary in porosity in cross section to control the movement of the bleach toward the teeth.

  The nanofiber structure may have a predetermined change profile in cross-section to predetermine the release profile of the bleach toward the teeth.

  The porosity of the nanofiber structure may increase from the side contacting the base layer to the side contacting the tooth surface.

  The nanofiber structure may be a laminated nanofiber structure comprising at least two layers of nanofibers having different diameters.

  The tooth bleaching system has a base layer for supporting the nanofiber structure, the base layer being substantially waterproof and water insoluble.

  The nanofiber structure includes a fiber having a pH adjusting material.

  The pH adjusting substance is any one or a combination of sodium hydroxide, hydrogen chloride, sodium phosphate, sodium bicarbonate, sodium stannate, citric acid, and sodium citrate.

  The pH adjusting substance in the tooth bleaching part is 0.1 to 10% by weight based on the tooth bleaching part.

The nanofiber structure may include a fiber made of polyamide manufactured by electrospinning using a mixture of formic acid and acetic acid. The ratio of formic acid and acetic acid may be in weight percent between 90 and 10 to 10 and 90, preferably between 30 and 70 to 70 and 30, and more preferably between 40 and 60 to 60 and 40. It may be 50 to 50 in weight percent ratio.

  The invention also relates to the use of a nanofiber structure as described above for bleaching.

  The present invention also relates to a method for whitening teeth, the method comprising immersing the nanofiber structure in a tooth bleaching section and a predetermined number of times the soaked nanofiber structure in the tooth. Applying and then removing the nanofiber structure. The tooth bleaching section is initially housed in a sealed container. The tooth bleaching part may be accommodated together with the nanofiber structure. They may be contained in a container into which the tooth bleaching part is poured. Such containers are sealed using plastic or carbon film. In order to immerse the nanofiber structure, the nanofiber structure is placed in a container with the nanofiber structure facing the tooth bleaching portion.

  The method may further include initial contact between a pH control agent and the bleaching agent during the immersion of the nanofiber structure. The method may further include supplying a tooth bleaching portion to a container for immersing the nanofiber structure prior to immersing the nanofiber structure.

The present invention also relates to a method for producing a nanofiber structure, the method comprising electrospinning a nanofiber using a mixture of formic acid and acetic acid. The ratio of formic acid and acetic acid may be in weight percent between 90 and 10 to 10 and 90, preferably between 30 and 70 to 70 and 30, and more preferably between 40 and 60 to 60 and 40. It may be 50 weight percent versus 50 weight percent.

  Particularly preferred forms of the invention are set out in the accompanying claims as independent and dependent claims. The features of the dependent claims incorporate the features of the independent claims and the features of the corresponding dependent claims.

  Although there have been certain improvements, changes and developments in the technical field of the present invention, the concept of the present invention provides a sufficiently new and novel improvement, and is a departure from the prior art. Results We believe that the present invention provides essential advantages, stability and reliability.

  With the suggestion of the present invention, improved methods and apparatus can be designed to produce fiber structures with better properties.

  The above-mentioned and other characteristics, features, and effects of the present invention will become apparent from the following detailed description with reference to the drawings. The drawings specifically illustrate the idea of the invention. This description is merely an example and should not limit the scope of the invention. The drawings referred to below are attached drawings.

It is a side view which shows the outline | summary of the electrospinning apparatus based on a prior art. It is a perspective view which shows the outline | summary of the electrospinning apparatus which concerns on embodiment of this invention. It is a perspective view which shows the outline | summary of the electrospinning apparatus which concerns on other embodiment of this invention. It is a perspective view which shows the outline | summary of the electrospinning apparatus which concerns on another embodiment of this invention. It is a top view which shows the outline | summary of arrangement | positioning of the discharge part used for the electrospinning apparatus which concerns on embodiment of this invention. It is a top view which shows the outline | summary of arrangement | positioning of the discharge part used for the electrospinning apparatus which concerns on other embodiment of this invention. It is a figure which shows an example of the laminated fiber structure which can be produced using the method and system which concerns on embodiment of this invention. It is a figure which shows an example of the nanofiber structure provided with the layer structure containing the layer which has an average diameter of 500 nm, and can be produced using the method which concerns on embodiment of this invention. FIG. 9 illustrates another layer of the example nanofiber structure of FIG. 8 having an average diameter of 300 nm. FIG. 9 is a diagram illustrating a relationship between a diameter of a nanofiber and a distance between a discharge portion and a receiving surface for the example of FIG. 8 and can be used in the embodiment of the present invention. It is a figure which shows the example of the nanofiber structure which has a layer structure containing one fiber which has an average diameter of 285 nm, and can be produced using the method which concerns on embodiment of this invention. FIG. 9 illustrates the other of the example nanofiber structures of FIG. 8 having an average diameter of 180 nm. FIG. 5 shows a profile of the distance between the discharge and the receiving surface and also shows the average diameter of the nanofibers at different concentrations and can be used in an embodiment of the invention. It is a figure which shows the fiber structure which has the sublayer prepared separately from the electrospinning process, and a peeling structure is obtained after applying mechanical force there. It is a figure which shows the fiber structure prepared according to embodiment of this invention, without producing delamination after applying a mechanical force. FIG. 2 shows a fiber structure having a sublayer prepared separately from the electrospinning process, where a peel structure is obtained after mechanical pressing. 1 shows an apparatus for manufacturing a wound dressing device having a fiber diameter that varies continuously in the z-direction, according to an embodiment of the invention. FIG. It is a figure which shows the outline | summary of the wound covering apparatus which can be produced using the apparatus shown in FIG. FIG. 3 shows an overview of different devices for manufacturing a wound dressing device having a laminated structure with a fiber diameter varying in the z-direction, according to an embodiment of the present invention. It is a figure which shows the outline | summary of the wound covering apparatus which can be manufactured using the apparatus shown in FIG. It is a figure which shows the outline | summary of the wound covering apparatus provided with waterproofness through all the thickness of a nanofiber structure, in order to prevent the movement of the fluid to the side of the wound covering apparatus which concerns on embodiment of this invention. It is a figure which shows the outline | summary of the wound covering apparatus provided with waterproofness only in a part of thickness direction of a nanofiber structure in order to prevent the movement of the fluid to the side of the wound covering apparatus which concerns on embodiment of this invention. . It is a figure which shows the outline | summary of the wound coating apparatus which has a small diameter fiber in the intermediate position which can be manufactured using the apparatus shown in FIG. FIG. 20 shows an overview of a laminated wound dressing device having a small diameter fiber in the middle position, which can be manufactured using the device shown in FIG. It is a figure which shows the example of the diagram display of the nanofiber structure used for the tooth bleaching system based on embodiment of this invention.

  The present invention will be described with respect to specific embodiments with reference to the drawings. However, the present invention is limited only by the scope of the claims and is not limited to the embodiments. The figures described are merely illustrative and not limiting. In the drawings, the dimensions of the members may be exaggerated and not shown in actual size for the purpose of illustration. Dimensions and relative dimensions do not correspond to actual reductions in actual practice of the invention.

  In addition, the terms first, second, third, etc. in the specification and claims are used to distinguish similar components and are in any order in time, space, hierarchy, etc. Does not mean. The terminology so used may be replaced under appropriate circumstances, and the embodiments of the invention described herein are described by procedures other than those described and illustrated herein. It should be understood that it may work.

  The term “comprising” is used in the claims and should not be construed as limited to the means listed thereafter, ie it does not exclude other elements or steps. It should be understood that the presence of a given function, quantity, step or member is clarified by its description and that one or more other functions, quantities, steps, members or combinations thereof It does not exclude existence or addition. Therefore, the scope of the invention described as “apparatus comprising A means and B means” is not limited to an apparatus composed only of the components A and B. That means only that the components associated with the device are A and B in the context of the present invention.

  References herein to “one embodiment” or “an embodiment” include at least one of the specific functions, configurations, or features described in connection with the embodiment. It is meant to be included in the embodiment. Accordingly, the descriptions of “in one embodiment (in)” or “in (in) an embodiment (in)” as used throughout this specification may refer to the same embodiment, In all descriptions, the same embodiment is not necessarily referred to. Furthermore, the particular functions, configurations, or features may be combined in any suitable manner as would be apparent to one having ordinary skill in the art from the one or more embodiments herein. May be.

  Similarly, in describing the exemplary embodiments of the invention, various functions of the invention have been described in order to streamline and facilitate understanding of one or more disclosures of the various invention forms. It should be well understood that they may be combined in one embodiment, drawing or description. However, such disclosure is not to be understood as representing an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as described in the claims, the inventive aspects of the invention are part of the overall features of one of the embodiments described below. The following claims are hereby expressly incorporated into this specification, with each claim standing on its own as a separate embodiment of this invention.

  Furthermore, some embodiments described in this specification include some of the characteristics other than those included in the other embodiments, and combinations of characteristics of different embodiments are not included in the present invention. And form different embodiments as understood by a person skilled in the art. For example, in the claims, any of the description in each claim may be used in any combination.

  In the description herein, numerous specific details are set forth. However, embodiments of the invention may actually be implemented beyond these specific details. Further, in order to facilitate understanding of the present specification, conventional methods, configurations, and techniques are not described in detail.

  In order to assist in understanding the present invention, terms are described below.

  The term “increase” used for a parameter means that the parameter gradually changes to a higher (larger) value unless otherwise stated. The gradual change appropriately includes no change, that is, the parameter has a constant value. The term “decreasing” as used for a parameter means that the parameter gradually changes to a lower (smaller) value unless otherwise stated. The gradual change includes no change, that is, the parameter is a constant value.

  The term “continuously or monotonically increasing” used for a parameter means that the parameter gradually changes to a higher (larger) value, unless stated otherwise, where the incremental change is a change. It does not include that there is no error, that is, that the parameter is a constant value. The term “decreasing continuously or monotonically” as used for a parameter means that the parameter gradually changes to a lower (smaller) value, unless stated otherwise, where the incremental change is a change. It does not include that there is no error, that is, that the parameter is a constant value.

  The invention will now be described by a detailed description of a plurality of embodiments of the invention. Those skilled in the art may come up with other embodiments of the present invention within the scope of the technical idea of the present invention, and the present invention is defined only by the description of the appended claims. .

In a first aspect, the present invention is, for example, electrospinning apparatus for producing a fiber structure such as a nano-fiber structure related (electrospinning device).

In the first embodiment, the electrospinning apparatus includes a series of discharge units for producing a solution or a melt. The electrospinning apparatus of the present invention includes a plurality of nozzles, that is, includes two or more discharge units or three or more discharge units for producing a solution, a melt, or the like. The discharge part is provided in order to produce material. The material is a solution or melt material used in the production of fibers. The discharge part is, for example, a nozzle, a needle such as a metal needle, or a small hole. In the embodiment of the present invention, two or more (for example, three or more) discharge portions are separated from each other by a distance of at least 1 cm (for example, at least 4 cm). For example, the discharge part may be separated by a distance of 1 to 100 cm. By providing the discharge portions at a distance of 1 cm or more, the produced fiber structure is usually more porous and contains straight fibers than when the interval is narrow. By relatively increasing the interval between the discharge parts (for example, needles), the evaporation of the solvent is improved, and the produced fiber structure has a high porosity. Such an effect will come from the advanced fiber formation process at the time of fiber collection. Preferably, the distance between the two or more discharge parts is at least 4 cm, more preferably 6 cm or more, and even more preferably at least 8 cm. The maximum spacing is arbitrary and is set, for example, by the desired porosity.

  Due to the interval between the discharge portions, the fibers forming the fiber structure have a linear shape exceeding a distance of 5 μm or more, 10 μm or more, or 20 μm or more. In addition to or in addition to being linear, the majority (ie, 50% or more) of the fibers that form the fiber structure are cross-link free, ie, not cross-bonded to adjacent fibers. It becomes a state. The majority of the fibers are, for example, substantially cross-bonded at their contact points with adjacent fibers. According to an embodiment of the present invention, a fiber structure is produced that includes fibers that are non-cross-bonded and thus do not bond together. That is, in that case, the majority (eg, 50% or more, preferably 70% or more, more preferably 90% or more, more preferably 95%) of the fibers remain independent. As a result, the degree of cross-linking is less than 1 cross-bond per 1 mm fiber length, preferably less than 1 cross-bond per 5 mm fiber length, more preferably 1 cross-bond per 1 cm fiber length. Less, more preferably less than 1 cross-link per 5 cm fiber length, more preferably no cross-links over the entire fiber length. This effect is particularly prominent when the discharge part is separated by 4 cm or more. Cross-linking can be defined as a covalent bond that connects the polymer chain of one fiber to the polymer chain of an adjacent fiber. Weak physical interactions such as van der Waals forces or hydrogen bonds are not included in the definition of cross-linking.

  When more than two discharge sections are used, the discharge sections (eg needles) are preferably arranged so that each forms a triangular set (see FIG. 5). The distance between each discharge portion is a minimum of 1 cm and a maximum of 100 cm, more preferably a minimum of 4 cm and a maximum of 100 cm, and further preferably a minimum of 6 cm and a maximum of 100 cm. In embodiments of the invention, a volatile and / or easily ionizing solvent is used. The needle is positioned as shown in FIG. In FIG. 6, the position of each needle is the same as that shown in FIG. 5 except for the third row every two rows. In this case, the individual needles are not surrounded by the needles on all sides. Thereby, evaporation of the solvent from the fiber forming region can be promoted. The purpose of placing the needle as in FIG. 6 is to prevent a forward electrical discharge when using a volatile or ionized solvent. The number of discharge parts is not limited by the maximum value. For example, the number of discharge units in a certain form is, for example, 3 to 20000, and for example, 5 to 20000. Preferably, the number of drains (eg needles) used in one form is at least between 3 and 500 (see FIG. 5). Different rows, such as adjacent rows, of the discharge section may be parallel, but may be shifted according to the mutual positional relationship of the discharge sections. This may be evaluated with respect to the average direction of relative movement of the receiving surface. The discharge unit may be arranged such that the combination of the discharge units has a triangular shape. The different rows are, for example, zigzag discharge sections. A zigzag discharge portion may be provided for two adjacent rows of discharge portions.

The electrospinning apparatus according to the present invention includes a receiving surface. The receiving surface may optionally be covered by a perforated or non-perforated layer, for example a perforated or non-perforated polymer / plastic layer. The receiving surface may be a perforated portion of a wide surface and need not be perforated in all portions. For example, the receiving surface may be part of a large belt that includes curved parts. The surface may include a liquid surface on which the fibers are disposed. A receiving surface is provided for receiving the product from two or more, preferably three or more pairs of outlets. The receiving surface may be a metal plate, foil, fibrous structure, liquid surface, and the like. The receiving surface is disposed at a predetermined spatial position. For example, the receiving surface is disposed in a horizontal direction, and the discharge portion is disposed above the receiving surface, or the receiving surface is disposed above the discharge portion. In those cases, therefore, the discharge parts are respectively arranged below or upward. For example, a discharge (eg, a needle) is placed on the lower plate and a jet of solution or melt (eg, a polymer solution or melt) moves toward the top of the device. The receiving plate may be arranged in the vertical direction. Of course, the receiving plate may be oriented in other directions (for example 45 ° with respect to the horizontal direction or any other direction). A combination of the discharge part and the receiving surface is also called a spinneret. At least one of the receiving surfaces and the set of discharge portions are provided so as to be movable. That is, one or more relative movements may be provided between the receiving surface and the discharge set. In the embodiment of the present invention, the direction in which the discharge portion is movable may be parallel to the receiving surface or may be perpendicular to the receiving surface. The movement of the discharge portion may be a combination of movement parallel to the receiving surface and movement perpendicular to the receiving surface.

  In the embodiment of the present invention, the movement of the discharge part is preferably a reciprocal movement, for example, a movement between two fixed points. The reciprocating movement is preferably parallel to the receiving surface and perpendicular to the direction of movement that causes the growth direction of the length of the fiber structure. The movement of the receiving surface may be parallel to the receiving surface and perpendicular to the receiving surface or a combination of both. Preferably, in the embodiment of the present invention, the receiving surface may continuously move in one direction parallel to the receiving surface. Preferably, the device is provided to provide a relative movement between the discharge set and the receiving surface, the relative movement being for example a first direction parallel to the receiving surface and parallel to the receiving surface. Is a combination of relative movement with the second direction, which is a direction different from the first direction.

  For example, the receiving surface is provided to move relatively in a direction at a predetermined angle with respect to the first direction, for example, in a direction substantially perpendicular to the first direction. The first and second directions may be perpendicular to each other and parallel to the receiving surface. Preferably, the ejector set and the receiving surface are movable relative to each other such that the ejector set moves in a first direction parallel to the accepting surface (eg, the y-direction shown in FIG. 2). The movement is, for example, a reciprocating movement, for example, a reciprocating movement between two reverse rotation positions. The receiving surface continuously moves in a second direction (eg, the x direction shown in FIG. 2) that is perpendicular to the first direction but parallel to the receiving surface. Such reciprocating movement of the discharge part makes it possible to superimpose products from the discharge part when they are received on the receiving surface from different discharge parts.

  The product from the drain that is received on the receiving surface is also referred to as a fiber umbrella on the receiving surface. Fiber umbrellas have a strong tendency to repel each other due to their charge. Therefore, if designed as a stationary system, i.e. a system that does not have a relative reciprocal movement between the receiving surface and the discharge set, it is not easy to superimpose. The relative reciprocating distance may be selected such that the discharges from adjacent discharges are discharged at least in an overlapping manner. Furthermore, the width of the produced fiber structure is increased by the method using reciprocation. The set of discharges is preferably affected by relative reciprocation relative to the receiving surface at an average speed of between 0.1 cm / s and 100 cm / s in the longitudinal growth direction of the fiber structure. Furthermore, the relative movement is preferably a continuous relative movement in one direction parallel to the receiving surface between the discharge and the receiving surface, thereby increasing the surface area of the larger fibrous structure. It becomes possible to produce continuously. The preferred moving speed of the receiving surface is between 10 cm / h and 100 m / h.

The electrospinning apparatus of the present invention further includes a power source for providing a potential difference between the discharge portion and the receiving surface. The power source may be a DC high voltage power source that provides a selected potential difference in the range of 100 to 200,000 V to the spinneret (ie, between the discharge and the receiving surface). For example, the drains (eg, needles) may be electrically connected to each other via a conductive (eg, metal) plate or by holding the structure. In other embodiments, a semiconductor or non-conductive first material plate (e.g., a single plate) or holding structure is made of, e.g., metal for electrically connecting all drains (e.g., needles). It may be used with means such as a wire. The power source may be connected to a conductive structure that forms the drain or means (eg, a wire) for electrically connecting all drains (eg, needles). The receiving surface is preferably grounded. It may be used without being grounded (floating), but in that case it is desirable to provide means for safety. Alternatively, the receiving surface may be set at a predetermined voltage using a second DC power source.

  In a preferred embodiment of the invention, the power supply is programmable or configurable. The power source used may be adjusted or controlled as a function of the distance from the discharge (tip) to the collection (receiving surface). This may be performed manually or automatically. The power supply used is optimized to allow stable operation.

Further, the system may be provided to obtain information regarding parameters associated with the polymer solution. The parameters are those that affect the stable operation of a system that produces fibers having a relatively constant diameter. An electrospinning system may be provided, for example, to obtain as data input or by information measured on some or all of the polymer concentration used, charge concentration, solvent used or viscosity.

The electrospinning apparatus according to the embodiment of the present invention further includes at least one accommodating unit for providing a solution or melt that is electrospun from the discharge unit. The container includes a polymer solution or a melt. The accommodating portion may be outside the electrospinning apparatus.

The electrospinning apparatus according to the embodiment of the present invention preferably further includes means for supplying a solution or a melt to the discharge portion. The means for supplying the solution or melt may be any means known to those skilled in the art. Examples of means for supplying the solution or melt to the discharge unit include, but are not limited to, a transfer means such as a tube in addition to a pump, a syringe, and the like.

  For example, a solution or a melt (for example, a polymer solution or a melt) is sent to each discharge part (for example, a needle) by an individual means (for example, an individual screw pump). In certain embodiments, multiple channel means (eg, multiple channel screw pumps) may be used, with each channel delivering to one individual drain. Further, a plurality of multi-channel means (for example, pumps) may be used according to the total amount of polymer solution or melt required for the discharge part. In other embodiments, an anesthesia type pump may be used to deliver through a syringe to a drain (eg, a needle). The syringe is filled with a polymer solution or melt and placed in an anesthetic pump. Alternatively, the solution or melt may be delivered from the central tank to the discharge section. The tank is held at a predetermined constant pressure using, for example, a pressure regulating valve and / or compressed air. In certain embodiments, multiple volumes of drains (eg, needles) may be delivered from a single source, such as a screw or anesthesia pump. The injection rate (eg, pump speed) of a solution such as a polymer solution or melt per outlet (eg, needle) may be 0.01-500 ml / h.

  The solution or melt usable within the scope of the present invention may be any solution or melt known to those skilled in the art suitable for the formation of fibers by electron transfer. Solutions or melts are produced from the polymer. Suitable polymers are polyamide, polystyrene, polycaprolactone, polyethylene oxide, polylactic acid, polyacrylic acid, polyester amide, polyvinyl alcohol, polyimide, polyurethane, polyvinyl pyrrolidone, collagen, polyethylene co-vinyl acetate and alcohol, cellulose and Related products, chitosan, methacrylic resin, silk, or combinations thereof, but are not limited to these. The solution or melt may include metal dissolved as metal pieces or metal ions so that a metal containing fibers is formed. As an optional feature, the solution or melt may contain antibacterial, pharmaceutical, hydrophobic / hydrophilic or anticorrosive, catalyst, oxidizing / reducing, and other additives.

The electrospinning device of the present invention may further include a surrounding component, that is, a component surrounding other components of the electrospinning device. For example, the enclosing component forms a jacket around the spinneret, protects the spinneret from instabilities such as turbulence, and / or allows the solvent to regain stability. Turbulence is desirably avoided in spinnerets because turbulence can cause unstable jets of solutions or melts and can also cause fiber umbrellas on the receiving surfaces produced by those jets to become unstable. The surrounding component is formed, for example, by plates of non-conductive material connected to each other so as to form a sealed structure.

The electrospinning apparatus of the present invention may further comprise one or more temperature control means / systems. These temperature control means may be added to, for example, an electronic rotating device in order to improve productivity in the production of fibers. Temperature fluctuations affect the evaporation rate of the solvent and affect the final fiber diameter and structure porosity. Therefore, the temperature control means is useful. The solution or melt in the container is temperature controlled by using a container for temperature control (for example, in a liquid tank such as an oil tank or a water tank). The temperature control may be activated while the solution moves from the container to the outlet through the jacket tube. The jacket tube is connected directly or indirectly to a cooling / heating system such as a container for temperature control. The spinneret is temperature controlled by using means for carrying heated / cooled air in the spinneret. For example, the electrospinning apparatus of the present invention includes a temperature control system that can control the temperature in the range of 280 to 1500K.

The electrospinning apparatus according to the embodiment of the present invention is provided to operate in a steady state. This is realized by a process of adjusting parameters manually or automatically. In terms of changes in the distance from the nozzle discharge to the collector, changes in parameters for electrospinning , such as applied voltage, humidity or flow rate applied, are determined based on experience, for example. In principle, it is very useful to optimize the voltage applied when changing the distance between the nozzle discharge part and the collection part. Other parameters may also be adjusted, such as the starting material flow rate. The electrospinning device may further vary other processing parameters such as, for example, electronic spinning and / or material flow rates for humidity.

In order to adjust the flow rate of the material for electrospinning , for example, it may be equipped with a pump that can be controlled to change the feed rate of the material to the discharge section and has a variable and configurable discharge port A discharge part may be provided. In order to adjust the humidity, the electrospinning system may comprise a system for adjusting the humidity, such as a drying means and / or a humidifier. The adjustment of the processing parameters is performed by other appropriate methods according to a predetermined rule, according to a calculation model, based on trial and error. Optimization is performed, for example, by adjusting parameters until a steady state is reached. The steady state is determined when the Taylor cone is constant and the rotation is continuously performed. Finding such a steady state is suitably performed, for example, visually or using an optical detector. The parameter adjustment is performed manually or automatically, or by a method including automation. The tailor cone is in the shape of a distorted droplet generated by a droplet at the tip of the discharge portion, and has an elliptical shape when a high pressure is applied.

Electrospinning apparatus of the present invention, in order to achieve a predetermined fiber diameter along the dimensions for electrospun fiber structure (electrospun fibrous structure), the discharge section 5 (see FIG. 1 during the production of the fiber structure ) And the receiving surface 8 (see FIG. 1) so that a predetermined distance is provided. The electrospinning apparatus of the present invention has a discharge section 5 (see FIG. 1) and a receiving surface 8 (see FIG. 1) to enable a predetermined fiber diameter profile along the dimensional direction of the electrospun fiber structure. Is provided to provide a predetermined distance profile between. A predetermined fiber diameter profile is realized at the thickness of the electrospun fiber structure. This allows the electrospun structure containing the fibers to have a predetermined profile of the fiber diameter in one direction of the electrospun fiber structure. This is useful for controlling the properties of the electrospun fiber structure in that direction.

  The predetermined distance profile is, for example, the distance between the discharge part (5) and the receiving surface (8), which is perpendicular to the receiving surface and different discharge parts along the first direction. Although realized by reducing or increasing the thing, the present invention is not limited to this.

As an example, the predetermined distance profile is realized by realizing a monotonically decreasing or monotonically increasing distance between the discharge part (5) and the receiving surface (8). With this feature, an electrospun structure including fibers is provided, and the diameter of the fibers decreases, for example, monotonously decreases along the dimensional direction of the electrospun fiber structure. This may be released in a variety of ways other than manual, except for alternative methods as described in detail later herein. Providing a predetermined distance profile between the discharge (5) and the receiving surface (8), for example a (monotonic) decrease or increase along the length in which the fiber structure is manufactured This means that the assembly of the discharge part and the receiving surface are moved relative to each other in the direction perpendicular to the receiving surface using at least components, for example during electrospinning operation, or appropriately fixed in advance. This is realized by arranging the discharge portion above the receiving surface according to the determined distance profile (see Embodiment 1 described later with reference to FIG. 2). According to this, the distance between the receiving surface and each of the first set of discharge units and the second set of discharge units is also different.

  For example, when decreasing or increasing the fiber thickness profile, the discharge is positioned so that the lengthwise discharge from which the fiber structure is manufactured approaches the receiving surface (FIGS. 3 and 4). In an alternative, the discharge part above the receiving surface is arranged such that the longitudinally spaced discharge part from which the fiber structure is manufactured is further away from the receiving surface. This is done not only by changing the distance between the receiving surface and the discharge part, but also by changing the distance between different subgroups of discharge parts.

  Instead, the receiving surface is moved to change the distance or a predetermined placement angle, for example, to achieve a predetermined distance profile, for example, monotonically increasing or decreasing the distance from the discharge to the receiving surface. May be.

A first embodiment for realizing a predetermined distance profile is to reduce or increase the distance between the discharge part and the receiving surface, for example, so that all sets of discharge parts are produced during fiber production. Move relative to the receiving surface, vertically, preferably continuously (or move the receiving surface vertically relative to the set of discharges). In the present embodiment, in order to manufacture fiber structures having various fiber diameters in the thickness direction of the fiber structure according to a predetermined distance profile, the receiving surface that supports the manufactured fiber structure is more Exposed to the discharge part for a long time or repeatedly. After being exposed for a sufficiently long time or after a sufficient number of exposures, the fibrous structure is collected. Multiple exposures can be easily achieved by using a circulation belt. Alternatively, reciprocation of the receiving surface in the X direction may be used to produce large fiber structures while limiting the size of the electrospinning system.

  If the vertical relative movement between the receiving surface and the discharge set is discontinuous, a layered fibrous structure is produced, where each layer is a previously formed (lower) layer. Consists of fibers having different average diameters. If this movement is continuous, the average diameter of the fibers produced decreases continuously (or increases) along one direction (eg, thickness direction) of the fiber structure. In any part perpendicular to the dimensional direction, the change in fiber diameter is limited to less than 10%, for example. In the case of a system in which the fibrous structure moves in a direction perpendicular to the receiving surface during movement of the discharge part, the change in diameter of the part perpendicular to the thickness direction depends on the moving speed. If the receiving surface moves slowly, the change is small.

In an example for forming a fiber thickness profile, the set of ejectors moves vertically (eg, in the z direction) with respect to the receiving surface, and the acceptor surfaces set in the vertical direction (eg, in the z direction). Move toward, away from, or both, and move the ejector set and the receiving surface toward or away from each other. The distance between the discharge part and the receiving surface is preferably 1 cm to 100 cm, more preferably 4 cm to 100 cm. According to the first embodiment, the variation of the average fiber diameter can be made a function in the thickness direction of the produced fiber structure. In an electrospinning system, if the fiber structure is manufactured by prolonged or repeated exposure, the system performs a batch process.

In FIG. 2, the example of the electrospinning device according to the first embodiment provides a predetermined distance profile that decreases or increases the distance between the discharge part and the receiving surface, for example monotonically, x, Arranged in the y and z axis space. The z-axis is a vertical axis, and the x-axis and the y-axis are two horizontal axes that are perpendicular to each other. The apparatus includes a high-pressure power source 1 and a pump 2 (for example, a screw pump, an anesthesia pump, or a container maintained at a constant pressure by compressed air). The device comprises an upper member 7 having a set of 5 discharges (where needles are provided). It is provided flat on a horizontal plane. The device also comprises a receiving surface 8 (circulation belt) that repeatedly moves in the x direction. The device further moves the set of the discharge part 5 relative to the receiving surface 8 relative to the receiving surface 8 and the means 11 for moving / providing the solution or melt to the discharge part (in this embodiment a monotonous vertical z-direction). And means 10 for reciprocal movement in the y direction. The device is surrounded by an enclosing component 9 (in this form it is transparent) 9. The apparatus further comprises a discharge means 15 for removing the solvent. The drainage means may be connected to a chimney or solvent recovery system.

  In the example of FIG. 2, the high voltage power supply 1 is a DC power supply that can apply a voltage of 100 to 200000 V to a spinneret. The spinneret comprises two members 7 and 8 arranged in parallel to each other. The upper member 7 is a flat plate having a predetermined amount of holes. A metal needle 5 is disposed in the hole. The needles are electrically connected to each other via the metal plate 7. In another form, a semiconductor or non-conductive plate 7 may be used with a conductive (eg metal) wire connecting all the needles 5. The high voltage power supply 1 is connected to its upper plate 7 if it is conductive or to a wire connecting all the needles 5. The lower plate 8 is either a metal plate, foil or fiber structure. It is optionally covered by a polymer / plastic layer with or without holes. The plate is grounded.

  If desired, it may be used without floating, but it can be dangerous. In another embodiment, the upper and lower plates may be exchanged, in which case the needle is placed on the lower plate and the polymer jet moves toward the top of the device.

The apparatus of FIG. 2 operates as follows. A voltage is set between the discharge part 5 and the receiving surface 8. The liquid or melt to be electrospun is moved from the storage part to the discharge part 5 via the moving means (in this embodiment, a fixed tube) 11 by the operation of the means 2 for providing the solution or melt to the discharge part. Moving. During the electrospinning operation, to form a distance profile between the ejector and the receiving surface, the ejector is moved by the operation of the moving means 10 for moving the ejector set or for moving the accepting surface. By moving in the direction, relative movement occurs. This movement enables production according to a predetermined profile of the fiber diameter in the thickness direction of the produced fiber structure (eg, mat). The distance between the discharge part and the receiving surface preferably varies from 1 to 100 cm.

  The actual limit value is used according to the product specification. At the same time, the fiber structure in which the circulation belt 8 is formed is accumulated. By moving the receiving surface relative to the discharge part in one direction parallel to the receiving surface, for example, a monotonous, predetermined distance profile that reduces or increases the distance between the discharge part and the receiving surface is realized. Is done. At the same time, the upper plate 7 with the discharge 5 reciprocates between two reversal points in the y-direction to ensure a good overlap (also referred to as fiber umbrella) in the production of the solution or melt. To do. The umbrellas tend to repel each other, and if the y-direction reciprocation stops, it is detrimental to superposition. Reciprocal movement is therefore particularly desirable. Furthermore, the width of the nanofiber structure can be increased by using reciprocation in the y direction. By moving the receiving surface 8, a wide surface area of the nanofiber structure can be formed.

  According to the apparatus of FIG. 2, it is possible to produce a fiber structure that changes according to a profile in which the fiber diameter is predetermined, for example, along the thickness direction of the fiber structure that is monotonically produced. Although the present invention is not so limited, the predetermined profile of fiber diameter may be, for example, having a large diameter at the surface of the fiber structure and a small diameter at the surface of the fiber structure. The change in diameter may be continuous or discontinuous. When discontinuous, the fiber structure becomes a layered structure. The first embodiment is not applied to continuous production of a fiber structure. The two following embodiments enable continuous production of the fiber structure according to the present invention and are capable of batch production.

  The second embodiment provides a predetermined distance profile that decreases or increases the distance between the discharge portion and the receiving surface, for example, monotonically as appropriate. A plurality of sets of discharge portions are arranged along the length direction of the fiber structure to be produced. The discharge part is arranged along the length direction of the fiber structure to be produced according to a predetermined profile. For example, the set of discharge portions is arranged such that the distance to the receiving surface is closer to the distance along the length direction to the adjacent discharge portion (see FIG. 3). Thereby, a decreasing or increasing profile, for example a monotonically increasing or decreasing profile, can be realized. An alternative for an increase or decrease profile is to place a plurality of discharge sets along the length of the fiber structure produced, each discharge set being more than the discharge set. The receiving surface along the upper direction is disposed at a predetermined distance. Although these alternatives allow the production of continuous nanofiber structure surface regions, the embodiment of FIG. 2 only allows the production of fiber structures by batch processing.

In FIG. 3, the example of the electrospinning apparatus according to the second embodiment provides a predetermined profile. For example, a predetermined distance profile that reduces or increases the distance between the discharge and the receiving surface, which is monotonous as appropriate, is realized. Both the discharge portion and the receiving surface are arranged in the x, y, and z axis directions. The z-axis is a vertical axis, and the x-axis and the y-axis are two horizontal axes that are perpendicular to each other. This device comprises a set 5 of discharge sections, each connected to a high voltage power source 1 and a pump 2 (accommodated in a housing) arranged on a horizontal plane. The device also comprises a receiving surface (circulation belt) 8 provided to move in the x direction below the set of discharge sections. The system also comprises means 11 for moving / feeding the solution or melt to the discharge. The means 10 for moving the discharge unit set 5 with respect to the receiving surface 8 is not necessarily required in the present embodiment, but may be provided as appropriate. Such means 10 is useful for applying the distance between each set of drains and the receiving surface to the particular fibrous structure being produced.

The electrospinning apparatus of FIG. 3 is particularly suitable for continuous production, and particularly suitable for continuous production of layered fiber structures. That is, the number of layers with different fiber diameters in the laminated structure determines the number of modules (sets of discharges) required. It is not limited in principle (FIG. 3 shows a device with two modules). Furthermore, it is useful to increase the productivity of laminated nanofiber structures by using modules belonging to each other.

In operation, the apparatus shown in FIG. 3 operates as follows. A power source is arranged between the discharge set 5 and the receiving surface 8. The solution or melt for electrospinning is supplied from the storage unit to each of the discharge unit sets 5 through the transmission means (in this embodiment, a flexible tube) 11 to supply the solution or melt to the discharge unit. It is transmitted by the operation of means 2 of The receiving surface continuously moves in the x direction while the formed fiber structure is withdrawn from the receiving surface. During movement in the x direction, the receiving surface is exposed to production, for example by a uniform discharge. At the same time, the discharge part reciprocates in the y direction in order to satisfactorily superimpose the product from the discharge part on the receiving surface.

  The third embodiment provides a predetermined distance profile that reduces or increases the distance between the discharge and the receiving surface, for example. The discharge part is arranged in a plane that is not parallel to the receiving surface. The device of the second embodiment provides a predetermined distance profile (see FIG. 3) that reduces or increases the distance between the discharge and the receiving surface, for example (see FIG. 3), and the produced fiber structure is layered. None, the fiber diameter varies discretely between the two layers. In the third embodiment, a predetermined distance profile is provided that reduces or increases the distance between the discharge and the receiving surface, for example, and the change in diameter of the fibrous structure over a predetermined range is smooth. For example, the diameter changes continuously over the thickness direction of the produced fiber structure.

  In one example, the set of discharge portions is provided in a plane where the discharge portions are not parallel to the receiving surface. The set of discharges (eg the upper plate comprising them) is inclined between 5 ° and 50 ° relative to the (mostly horizontal) receiving surface. As a result, the distance from the discharge (eg the tip of the needle) to the receiving surface (for each row of needles) is continuous along the x direction, ie along the length of the fiber structure to be produced. Increase or decrease. Preferably, the discharge portion is oriented perpendicular to the receiving surface regardless of the angle. In an example embodiment, a predetermined distance profile between the discharge and the receiving surface as schematically shown in FIG. 4 is provided. In this configuration, a laminated nanofiber structure is produced continuously and exhibits a smooth nanofiber diameter profile as a function of depth (see FIG. 7). In contrast, in the configuration of FIG. 3, the nanofiber diameter varies discretely between layers.

In FIG. 4, the example of the electrospinning device according to the third embodiment provides a predetermined distance profile between the discharge part and the receiving surface and is arranged in the x, y and z axis spaces. The z-axis is a vertical axis, and the x-axis and the y-axis are two horizontal axes that are perpendicular to each other. This device comprises two flat discharge sets 7, each connected to a high-voltage power source 1 and a pump 2 (accommodated in a housing). They are also arranged obliquely with respect to the receiving surface 8 in this example. Different distance profiles may be applied. The receiving surface 8 is provided so as to move in the x direction under both discharge portions. The system also comprises means 11 for moving / feeding the solution or melt to the discharge. Means 10 for moving the discharge unit set 5 relative to the receiving surface 8 (in this embodiment, a monotonous vertical movement in the z direction and a reciprocating movement in the y direction) is not necessarily required in this embodiment. However, it may be provided as appropriate. Such a means 10 is useful for making the slope of the surface formed by the set of discharge sections different in the distance between each set of discharge sections and the receiving surface. This makes it possible to produce different fiber structures using the same device.

In operation, the apparatus shown in FIG. 4 operates as follows. A power source is arranged between the discharge set 5 and the receiving surface 8. The solution or melt for electrospinning is supplied from the storage unit to each of the discharge unit sets 5 through the transmission means (in this embodiment, a flexible tube) 11 to supply the solution or melt to the discharge unit. It is transmitted by the operation of the means 2 in FIG. The receiving surface continuously moves in the x direction while the formed fiber structure is withdrawn from the receiving surface. During movement in the x direction, the receiving surface is exposed to production by, for example, increasingly closer discharge units arranged at different distances. At the same time, the discharge part reciprocates in the y direction in order to satisfactorily superimpose the product from the discharge part on the receiving surface.

In one embodiment, the electrospinning apparatus of the present invention comprises moving means for moving the set of ejectors and / or the receiving surface. The moving means includes, but is not limited to, one or more motors and one or more operating means such as a transmission shaft. The moving means allows for one or more relative movements as described above.

The apparatus may include a control unit for controlling the moving unit and for controlling the movement of the discharge unit and the receiving surface during the production process of the fiber structure. In addition, the control unit is configured so that the distance between each set of the discharge unit related to the target fiber structure and the distance so that a predetermined change in the distance is obtained during the fiber structure production process (for example, one electrospinning process). / Or inclination may be set. This may be performed without stopping the electrospinning process and / or without substantial delay between nanofibers deposited with different diameters. The substantial delay between nanofibers deposited with different diameters is less than 60 seconds, preferably less than 10 seconds, more preferably less than 1 second. In a preferred embodiment, there is no delay between nanofibers deposited with different diameters. The control unit includes not only hardware but also software. It controls the synchronization or application method for performing the method for the electrospinning apparatus using the system described above. The present invention also relates to such a control unit. The control unit includes processing means, and is particularly provided to execute the control task of electrospinning as described above.

A preferred embodiment according to the present invention uses the above-described electrospinning apparatus, and a change in the distance between the discharging part (tip) and the collecting part (receiving surface) occurs during electrospinning , and as a result, the receiving surface. There is no delay between nanofiber materials with substantially different diameters deposited in This makes it possible to obtain a strong nanofiber structure that does not risk tearing during normal use or when an intervening force is applied.

In a preferred embodiment according to the present invention, the electrospinning system provides highly productive and mechanically strong nanofibers.

  In a second aspect, the present invention relates to a method for producing a fibrous structure. The method includes providing a set of discharges for discharging a solution or melt, providing a receiving surface for receiving a product from the set of discharges, and parallel to the receiving surface. Moving the receiving surface in a first direction, providing a potential difference between the set of discharge parts and the receiving surface during the movement, that is, applying a voltage, and applying a solution or melt to the discharge part. Providing a liquid. According to an embodiment of the present invention, while providing the solution or melt to the discharge part, the change in the distance between the discharge part of the device and the receiving surface is the predetermined fiber thickness for the fiber structure. In order to realize the profile, follow a predetermined profile. The predetermined profile is a profile that decreases monotonously as appropriate along the first direction. This profile can be achieved by system placement (eg, the embodiment of FIGS. 3 and 4) or by relative movement of the set of drains relative to the receiving surface. Furthermore, the mechanism relating to producing a distance between at least a part of the discharge part of the device and the receiving surface according to a predetermined profile may be as described in the first embodiment.

In an embodiment according to the present invention, an excellent non-chemical effect between different nanofibers can be obtained by changing the distance between the discharge part and the receiving surface during the deposition, whereby nano Adhesion between fibers occurs, and a structure with excellent mechanical strength can be realized. Since the structure can be provided by a single electrospinning , the adhesion between the different fibers is sufficiently good and can produce a rigid structure while not forming, for example, cross-linked fibers. In particular, by depositing the next layer of fibers while the previous layer is still somewhat moist, for example while the liquid content is 2% to 6%, or 2% to 5%, the different fibers There is a tendency to bite each other slightly. The stinging cross is a weak relationship, not a chemical relationship, not a cross bond. The method is preferably carried out using a system as described in the first aspect.

  The potential difference may be selected between 100V and 200000V. The moving step is performed by an actuating means for further moving the set of drains and / or the receiving surface to allow for an excellent filling of the fiber structure. As a result, the set of at least one receiving surface and discharge is further moved. The further movement of the discharge part may be a reciprocating movement between two fixed points, for example. Preferably, the receiving surface further moves continuously parallel to the receiving surface. Preferably, the set of discharge portions further reciprocates in a first direction parallel to the receiving surface. The receiving surface further moves in a second direction that is parallel to the receiving surface and different from the first direction. For example, the receiving surface further moves at a predetermined angle with respect to the first direction, and optionally in a direction substantially perpendicular to the first direction. The first and second directions are perpendicular to each other and parallel to the first surface and the receiving surface. Preferably, the ejector set and the receiving surface are further relative to each other such that the ejector set moves along the y direction between two reversal points (see, eg, FIG. 2, FIG. 3 or FIG. 4). Move on. The receiving surface further moves continuously in a direction perpendicular to the y direction (eg, the x direction in FIG. 2, 3 or 4), but not in the plane of the receiving surface. The set of ejectors may further move at an average speed between 0.1 cm / s and 10 cm / s. The receiving surface may move at a speed between 10 cm / h and 100 m / h.

  The solution or melt is held in a storage unit that is not necessarily temperature-controlled. Providing the solution or melt is realized by a solution or melt actuating means for providing the solution or melt to the outlet. These means (for example, a pump) transmit the solution or melt to the discharge part via the transmission means, but the temperature is not necessarily controlled. At the discharge, the solution or melt forms a droplet that is drawn to the return receiving surface of the action of the potential difference as the filament is drawn. The receiving surface acts as a collecting surface. The injection shape of the solution or melt exiting from the discharge part is usually conical, and forms a so-called umbrella shape, that is, a region that covers the receiving surface.

According to an embodiment according to the invention, during electrospinning , the distance between the discharge part of the system and the receiving surface changes, so that nanofiber structures of various diameters, for example nanofibers with different diameters, are obtained. It is possible to produce a layered nanofiber structure comprising a sublayer having a mechanically strong nanofiber microstructure.

According to the embodiment of the present embodiment, the electrospinning method may change other parameters for electrospinning from the viewpoint of changing the distance from the nozzle discharging unit to the collecting unit. Other parameters are, for example, changing the applied voltage, humidity, flow rate of the melt or solution supplied to the nozzle. Solution or melt parameters may be considered and varied. Such parameters are the polymer used, the charge density, the solvent used, and / or the viscosity. Such adjustment or optimization has been experimented. Optimizing the applied voltage is extremely useful when changing the distance between the discharge section and the collection section. The change of one or more parameters is performed according to predetermined rules, according to a calculated model, based on trial and error experience, or in any other suitable manner. Optimization is performed, for example, by adjusting parameters until a steady state is obtained. The steady state can be defined as the case where the tailor cone is constant and the rotation is continuously performed. Such steady state detection is achieved optically, ie visually or using an optical detector, and parameter adjustment is performed in a manual, automatic or partially automated manner.

According to embodiments of the present invention, such control, adjustment and / or optimization of processing parameters can produce bead-free fiber structures, and the fiber diameters of the structures. Can be varied within the same electrospinning session. In an embodiment according to the present invention, taking into account the above-mentioned parameters, a window including nanofibers, for example, fibers with no balls or a small amount of balls can be created under steady state. . Long processing times can be obtained, which can reduce or eliminate the risk of creating a large number of balls in the nanofiber, and also reduce or eliminate the risk of not producing nano-fibers. Can do. By realizing a long processing time operating in steady state, it becomes possible to produce nanofibers continuously in a manner that is very easy to regenerate.

In a third aspect, the present invention relates to a fiber structure. The first embodiment of the fiber structure according to the present invention shows much usefulness and innovation as compared with the conventional general nanofiber structure. These features are realized through the characteristics of the used electrospinning device according to the first aspect of the invention. In the fiber structure of the present invention, the diameters of individual fibers vary along the dimension of the fiber structure, for example, across the thickness direction of the fiber structure. In an embodiment, the invention relates to an electrospun fiber structure comprising fibers, wherein the fiber diameter varies according to a predetermined profile and decreases or monotonically along a dimensional direction of the electrospun fiber structure. Decrease. In any part, the change in the fiber diameter in the direction is less than 10%. The predetermined profile is, for example, minimizing the fiber diameter in the middle of the fiber structure in the depth direction. In an embodiment, the electrospun fiber structure of the present invention is a laminated structure consisting of nanofiber layers, each subsequent layer consisting of fibers having a smaller diameter than the fibers of the previous layer. The average diameter of the fibers varies according to a predetermined profile, for example, monotonically decreasing or increasing over the thickness of the electrospun fiber structure.

In the present invention, the electrospun fiber structure can be cut into a desired shape according to the requirements of the envisaged application. The surface area varies from 5 mm 2 to 10 m 2, the thickness varies from 100 nm to 30 cm, and the diameter of the individual fibers varies from 3 nm to 5 μm. In an embodiment, the electrospun fiber structure of the present invention is porous. The electrospun fiber structure is preferably at least 65% porous. The pore size varies from 30 nm to 8 μm.

The electrospun fiber structure of the present invention mainly contains 50% or more linear fibers. In one embodiment, the fibrous structure forms a mat. It is estimated from image analysis that the fibers are straight. Preferably, the majority (ie, 50% or more) of the fibers contained in the fiber structure are linear, ie from substantially linear main (ie, 50% or more) segments that are substantially longer than 5 μm. Become. By being substantially straight, the main axis of the fiber, ie along the length of the fiber, is less than 45 °, for example 30 °, within a length of 10 micrometers in which the change in angle is measured. It should be understood that the angle changes by less than, less than 15 °, or less than 5 °. This angle can be measured between the tangents at the two points of the main axis over the length of the fiber considered. The standard deviation of linearity over the distance in question does not exceed 5%.

The fiber structure of the present invention contains little or no cross-linking. For example, in a microfiber or nanofiber structure, the majority (ie, 50% or more) of the fibers that form are substantially non-cross-linked. The fiber structure is an electrospun fiber structure and is a structure made by electrospinning . They are not cross-bonded to adjacent fibers. Cross-bonding means that not only the two fibers are in contact, but the two fibers are bonded. This is a result of opening a space of at least 1 cm, preferably at least 4 cm. This effect is not limited by theory, and it is considered that the solvent can easily and quickly evaporate during fiber formation. If a space shorter than 1 cm is opened in the discharge section, the solvent takes a long time to evaporate during fiber formation. Thereby, adjacent fibers are fused and cross-bonded. If the fiber structure is made from melt, the problem is that the thermal effects that occur when the discharges are too close to each other cannot be ignored. Fiber formation is not complete, and a kind of intermediate phase is formed between the melt and the solid, forming a fiber cross-bond. Another useful feature of the fibrous structure produced is that it has a porosity of at least 65%, preferably 65 to 99%.

  The cross-bonds between the fibers are weak and non-chemical relationships that cause the nanofibers to pierce and improve the mechanical strength obtained in the structure according to the present invention. Such a relationship improves the strength of the nanofiber structure according to the present invention, but the adverse effects caused by cross-coupling cannot be avoided.

  In an embodiment, the present invention also relates to a fiber structure having a uniform fiber thickness. That is, the standard deviation of the thickness through the fiber structure does not exceed 80%, preferably 50%, more preferably 20%.

  The present invention relates to a fibrous structure having all or more of the above features. As an optional feature, the fiber structure according to the present invention is such that most of the fibers (ie 50% or more) are randomly oriented and not oriented in a specific direction (ie not aligned). This effect is useful for increasing porosity. In the embodiment, this effect can be obtained by selecting the moving speed of the receiving surface of, for example, 10 cm / h to 100 m / h by continuously moving the receiving surface in a certain direction.

  As an optional feature, the majority of the fibers (ie, 50% or more of the fibers) contained in the fiber structure of the present invention have a diameter of 3 nm or more and a diameter of 10 nm or more. As an optional feature, the diameter of the majority (ie 50% or more) of the fibers contained in the fiber structure of the present invention has a diameter of 2000 nm or less, preferably 800 nm or less, more preferably 700 nm or less. If the fibers have an average diameter of 800 nm or less, they are referred to as nanofibers, and the fiber structure made therefrom is a nanofiber structure. As an optional feature, the diameter of the majority (ie 50% or more) of the fibers contained in the fiber structure of the present invention is 3 to 2000 nm, preferably 10 to 2000 nm, preferably 3 to 800 nm, more preferably Has a dimension of 10 to 700 nm. The fibers have a diameter where local unintentional changes are less than 100% of the diameter dimension over the full length, more preferably less than 50% of the diameter dimension over the full length. If the local unintentional deviation in diameter is greater than 200% with respect to the average diameter, such fibers are not referred to as fibers but are referred to as beaded fibers.

  As can be seen from the examples, the fiber diameter depends on the distance between the discharge and the receiving surface. The profile of the relationship between fiber diameter and distance depends on the polymer and the solvent. Since the profile is specific to the polymer and solvent, it can only be determined by examining the polymer solution or melt. It is determined by trial and error, by experimental results, by a theoretical model, and so on. As another optional feature, the fibrous structure produced has a width of 15 to 10,000 cm.

  In an embodiment of the third aspect of the invention, the fiber polymer structure has a porosity of at least 65% and a width of 15 to 10,000 cm. According to the method of the second form applied to the apparatus of the first form, it is possible to produce a fiber structure having a remarkable characteristic in the change of the fiber diameter in the cross section of the fiber structure.

  In an embodiment of the third embodiment, a laminated or multi-layered fiber structure is produced. Preferably, the average fiber diameter is different for each set of adjacent layers of the fiber structure. This is achieved by using different distances between the drain and the receiving surface for each layer (see FIG. 3). The laminated fiber structure that is produced has a number of utilities compared to those that are not laminated. First, the combination of the small-diameter fiber layer and the large-diameter fiber layer improves the overall strength of the fiber structure. Secondly, the absorption / release characteristics of the fiber structure can be optimized according to the function of the application, which is done in a single production step. Finally, multiple tasks and multiple functions are obtained by using a laminated structure.

While the apparatus of the present invention has been described with reference to specific configurations, not just materials, various modifications and improvements can be made without departing from the scope of the present invention. For example, steps may be added to or deleted from the method described above within the scope of the present invention. The invention described above with respect to production methods, electrospinning devices and fiber structures is a control that controls the relative distance between the discharge and the receiving surface to produce different properties between different layers of the fiber structure. Also related to the device.

A number of embodiments are shown and described. Examples 1 to 3 show examples of the diameter change in the depth direction of the nanofiber structure produced in the experiment of one electrospinning apparatus. Examples 4 and 5 are examples showing steady states for electrospinning of different materials. Examples 7, 9, 11 and 13 describe electrospinning experiments. There, strong nanofiber structures are produced using the method according to embodiments of the present invention. Examples 6, 8, 10 and 12 describe comparative experiments with different electrospinning . There, different sublayers of nanofiber structures are produced during different electrospinning experiments that are separated in time. These experiments and comparative experiments illustrate the utility of the embodiments according to the present invention. Example 14 describes results similar to those described in Examples 4-13, but the materials are different. Thus, it will be described that the method and system for electrospinning according to the embodiment of the present invention can be widely applied and is not limited to materials by electrospinning .

Example 1
Polyesteramide (PEA) synthesized from fatty acid and having a molecular weight of about 20.000 g / mol is dissolved in chloroform to obtain a 25% PEA solution. The solution is delivered to the discharge set 24 using a multi-channel screw pump at a flow rate of 15 ml / h per discharge. In order to allow electrospinning of the polymer solution, the outlet and receiving surface are placed in an electric field applied to a 1000 V / cm spinneret. The discharge portions are arranged in a triangular shape, and are arranged in four rows having six discharge portions per row. The temperature control is performed at 298K. The discharge surface is disposed at an angle of 10 ° with respect to the receiving surface, and the discharge surface moves perpendicular to the movement of the receiving surface. The speed of the receiving surface is 40 cm / h, and the speed of the discharge surface is 1 cm / s. After 2 hours of electrospinning , nanofiber structures with a thickness of 300 μm, a length of 1.5 m and a width of 80 cm are produced. The average diameter of the nanofibers varies as a function of thickness from 500 nm (see FIG. 8) on one side of the structure to 300 nm (see FIG. 9) on the other side. The side with the largest diameter depends on the fiber produced from the discharge located closest to the receiving surface. The smallest diameter (on the other side of the nanofiber structure) is produced from the discharge that is furthest away from the receiving surface. FIG. 10 shows the relationship between the diameter of the nanofiber and the distance between the outlet and the receiving surface.

(Example 2)
Polyamide 6/6 (PA66) has a molecular weight of about 20.000 g / mol and is dissolved in formic acid to form a 14% PA66 solution. The solution is delivered to each of the 24 sets of 24 outlets in two sets at a flow rate of 2 ml / h per outlet using a plurality of multi-channel screw pumps. In order to allow electrospinning of the polymer solution, the discharge and receiving surface are placed in an electric field hung on a 3.500 V / cm spinneret. The discharge portions are arranged in a triangular shape, and are arranged in four rows having six discharge portions per row. Two spinnerets are used, each used at a different distance between the drain and the receiving surface. The temperature control is performed at 298K. The first discharge part surface is arranged at a distance of 4 cm from the receiving surface, and the second discharge part surface is arranged at a distance of 6 cm from the receiving surface. The speed of the receiving surface is 60 cm / h, and the speed of the discharge surface is 1 cm / s. After two hours of electrospinning , a nanofiber structure with a thickness of 100 μm, a length of 1.2 m and a width of 80 cm is produced. The average diameter of the nanofibers varies in one step as a function of thickness from 285 nm (see FIG. 11) on one side of the structure to 180 nm (see FIG. 12) on the other side. The side with the largest diameter is dependent on the fiber produced from the discharge surface located 4 cm from the receiving surface. The smallest diameter (on the other side of the nanofiber structure) is produced from the discharge surface located 6 cm from the receiving surface.

  FIG. 13 shows the profile of the distance between the discharge and the receiving surface and the average diameter of the nanofibers produced using the process described in Example 1.

(Example 3)
Cellulose acetate (CA) has a molecular weight of about 30.000 g / mol and is dissolved in a solution of acetone / dimethylacetamide mixed at a ratio of 2: 1 to form a 14% CA solution. The solution is delivered to each of the 24 sets of 24 outlets in two sets at a flow rate of 10 ml / h per outlet using a plurality of multi-channel screw pumps. In order to allow electrospinning of the polymer solution, the drain and receiving surface are placed in an electric field hung on a 850 V / cm spinneret. The discharge portions are arranged in a triangular shape, and are arranged in four rows having six discharge portions per row. Two spinnerets are used, each used at a different distance between the drain and the receiving surface. The temperature control is performed at 298K. The first discharge portion surface is arranged at a distance of 20 cm from the receiving surface, and the second discharge portion surface is arranged at a distance of 15 cm from the receiving surface. The speed of the receiving surface is 60 cm / h, and the speed of the discharge surface is 1 cm / s. After 2 hours of electrospinning , a nanofiber structure with a thickness of 200 μm, a length of 1.2 m and a width of 80 cm is produced. The average diameter of the nanofibers varies as a function of thickness from 470 nm on one side of the structure to 450 nm on the other side. The side with the largest diameter depends on the fiber produced from the discharge surface located 15 cm from the receiving surface. The smallest diameter (on the other side of the nanofiber structure) is produced from the discharge surface located 20 cm from the receiving surface.

Example 4
Polyamide 6/6 (PA66) is dissolved in formic acid to form a 14% PA66 solution. The solution is delivered to a set of needles using a plurality of multichannel screw pumps. The temperature control is performed at 298K. The needles are placed 6 cm from each other. Fibers in which steady state operation is achieved and, as a result, contain no beads or reduce or minimize balls by using operating parameters including distance from tip to collection section, flow rate and applied voltage Is produced.

  An excellent steady state is achieved by a combination of the distance from the tip to the collecting part, the flow rate and the applied voltage. The condition is achieved by manually adjusting the applied voltage for a fixed end-to-collector distance and a fixed flow rate.

(Example 5)
Example 5 describes an experiment similar to Example 4. Polyester polyamide obtained through a synthetic product using a fatty acid is dissolved in chloroform to form a 24% PEA solution. The solution is delivered to a set of needles using a plurality of multichannel screw pumps. The temperature control is performed at 298K. The needles are placed 6 cm from each other. Steady state operation is achieved, resulting in the distance from the tip to the collector (shown in row 1), the flow rate (shown in column 1), and the distance from the tip to the collector and the predetermined flow rate. By using operating parameters that include a voltage applied to (denoted in kV), fibers are produced that contain no beads or have reduced or minimal balls.

  As shown in the table, an excellent steady state is realized by a combination of the distance from the tip to the collection unit, the flow rate, and the applied voltage. The condition is achieved by manually adjusting the applied voltage for a fixed end-to-collector distance and a fixed flow rate.

(Example 6)
Polyamide 6/6 (PA66) is dissolved in formic acid to form a 14% PA66 solution. The solution is delivered using a plurality of multi-channel screw pumps. The flow rate per needle is 5 ml / h, the applied voltage is 4500 V / cm, and the distance from the tip to the collector surface is 6 cm. The temperature control is performed at 298K. The needles are placed 6 cm from each other. A first layer of nanofibers is produced. After 10 minutes, the second layer is provided under the same conditions. This is repeated 6 times to obtain a 7-layer laminated structure. The layers are formed between different electrospinning with sufficient time intervals. When a mechanical load is applied to the laminated structure, it exhibits weak strength due to the weak adhesion between each layer. The delamination of the 7 layers after applying mechanical force is shown in FIG.

(Example 7)
Polyamide 6/6 (PA66) is dissolved in formic acid to form a 14% PA66 solution. The solution is delivered using a plurality of multi-channel screw pumps. The flow rate per needle is 5 ml / h, the applied voltage is 4500 V / cm, and the distance from the tip to the collector surface is 6 cm. The temperature control is performed at 298K. The needles are placed 6 cm from each other. A first layer of nanofibers is produced. Immediately after, the second layer is provided under the same conditions. This is repeated 10 times to obtain an 11-layer laminated structure according to the embodiment of the present invention. When a mechanical load is applied to the laminated structure, an orderly nanofiber mat is formed that exhibits strong strength and cannot distinguish between the layers. FIG. 15 shows a structure in which delamination does not occur.

  Comparing Example 6 and Example 7, it can be seen that the nanofiber structure produced using the embodiment according to the present invention has excellent strength and excellent structure.

(Example 8)
Polyamide 6/6 (PA66) is dissolved in formic acid to form a 14% PA66 solution. The solution is delivered using a plurality of multi-channel screw pumps. The flow rate per needle is 2 ml / h, the applied voltage is 3500 V / cm, and the distance from the tip to the collector surface is 6 cm. The temperature control is performed at 298K. The needles are placed 6 cm from each other. A first layer of nanofibers is produced. After 10 minutes, the second layer is provided at a flow rate of 2 ml / h, an applied voltage of 3300 V / cm, and a distance of 7 cm from the tip to the collector surface. After another 10 minutes, the layer is provided at a flow rate of 2 ml / h, an applied voltage of 3500 V / cm, and a distance of 6 cm from the tip to the collector surface. Further, the fourth, fifth and sixth layers are provided at intervals of 10 minutes, with a flow rate of 2 ml / h, an applied voltage of 3300 V / cm, and a distance from the tip to the collector surface of 7 cm. The layers are formed between different electrospinning with sufficient time intervals. When a mechanical load is applied to the laminated structure, it exhibits weak strength due to the weak adhesion between each layer. The delamination of the structure is again shown in FIG.

Example 9
Polyamide 6/6 (PA66) is dissolved in formic acid to form a 14% PA66 solution. The solution is delivered using a plurality of multi-channel screw pumps. The flow rate per needle is 2 ml / h, the applied voltage is 3500 V / cm, and the distance from the tip to the collector surface is 6 cm. The temperature control is performed at 298K. The needles are placed 6 cm from each other. A first layer of nanofibers is produced. Immediately thereafter, the second layer is provided at a flow rate of 2 ml / h, an applied voltage of 3300 V / cm, and a distance from the tip to the surface of the collecting part of 7 cm. Subsequently, the third layer is provided at a flow rate of 2 ml / h, an applied voltage of 3500 V / cm, and a distance of 6 cm from the tip to the collector surface. Further, the fourth, fifth and sixth layers are provided immediately after each at a flow rate of 2 ml / h, an applied voltage of 3300 V / cm, and a distance from the tip to the collector surface of 7 cm. Nanofiber structures are produced during substantially the same electrospinning . Thereby, different sublayers are arranged between different electrospinning , and nanofibers having different diameters are provided substantially without time delay as in the embodiment of the present invention. When a mechanical load is applied to the laminated structure, an orderly nanofiber mat is formed that exhibits strong strength and cannot distinguish between the layers. The same result as in FIG. 15 is obtained.

  Comparing Example 8 and Example 9, it can be seen that the nanofiber structure produced using the embodiment according to the present invention has excellent strength and excellent structure. Furthermore, since they are different compounds, it can be seen that these results are substantially independent of the chemical composition of the materials used.

(Example 10)
Polyester polyamide is dissolved in chloroform to form a 24% PEA solution. The solution is delivered to a set of needles using a plurality of multichannel screw pumps. The flow rate per needle is 12 ml / h, the applied voltage is 750 V / cm, and the distance from the tip to the collector surface is 25 cm. The temperature control is performed at 298K. The needles are placed 6 cm from each other. A first layer of nanofibers is produced. After 10 minutes, the second layer is provided under the same conditions. This is repeated 10 times to obtain an 11-layer laminated structure. The layers are formed between different electrospinning with sufficient time intervals. When a mechanical load is applied to the laminated structure, it exhibits weak strength due to the weak adhesion between each layer.

(Example 11)
Polyester polyamide obtained through a synthetic product using a fatty acid is dissolved in chloroform to form a 24% PEA solution. The solution is delivered to a set of needles using a plurality of multichannel screw pumps. The flow rate per needle is 12 ml / h, the applied voltage is 750 V / cm, and the distance from the tip to the collector surface is 25 cm. The temperature control is performed at 298K. The needles are placed 6 cm from each other. A first layer of nanofibers is produced. Immediately after, the second layer is provided under the same conditions. This is repeated 10 times to obtain an 11-layer laminated structure according to the embodiment of the present invention. When a mechanical load is applied to the laminated structure, an orderly nanofiber mat is formed that exhibits strong strength and cannot distinguish between the layers.

Comparing Example 10 and Example 11, the nanofiber structure produced using the embodiment according to the present invention also has excellent strength and excellent structure even with different types of electrospinning solutions. I understand. This confirms that excellent structures can be produced using the methods and apparatus according to embodiments of the present invention, regardless of the materials used.

(Example 12)
Polyester polyamide obtained through a synthetic product using a fatty acid is dissolved in chloroform to form a 24% PEA solution. The solution is delivered to a set of needles using a plurality of multichannel screw pumps. The flow rate per needle is 12 ml / h, the applied voltage is 750 V / cm, and the distance from the tip to the collector surface is 25 cm. The temperature control is performed at 298K. The needles are placed 6 cm from each other. A first layer of nanofibers is produced. After 10 minutes, the second layer is provided at a flow rate of 12 ml / h, an applied voltage of 1400 V / cm, and a distance of 10 cm from the tip to the collector surface. After another 10 minutes, the layer is provided at a flow rate of 12 ml / h, an applied voltage of 750 V / cm, and a distance of 25 cm from the tip to the collector surface. Further, the fourth layer is provided at a flow rate of 12 ml / h, an applied voltage of 1400 V / cm, and a distance from the tip to the surface of the collecting unit of 10 cm. The layers are formed between different electron rotations with sufficient time intervals. When a mechanical load is applied to the laminated structure, it exhibits weak strength due to the weak adhesion between each layer. The delamination of the structure is again shown in FIG.

(Example 13)
Polyester polyamide obtained through a synthetic product using a fatty acid is dissolved in chloroform to form a 24% PEA solution. The solution is delivered to a set of needles using a plurality of multichannel screw pumps. The flow rate per needle is 12 ml / h, the applied voltage is 750 V / cm, and the distance from the tip to the collector surface is 25 cm. The temperature control is performed at 298K. The needles are placed 6 cm from each other. A first layer of nanofibers is produced. Immediately after, the second layer is provided at a flow rate of 12 ml / h, an applied voltage of 1400 V / cm, and a distance of 10 cm from the tip to the collector surface. Subsequently, the third layer is provided at a flow rate of 12 ml / h, an applied voltage of 750 V / cm, and a distance from the tip to the collector surface of 25 cm. Further, the fourth layer is provided at a flow rate of 12 ml / h, an applied voltage of 1400 V / cm, and a distance from the tip to the surface of the collecting unit of 10 cm. Nanofiber structures are produced during substantially the same electrospinning . Thereby, different sublayers are arranged between different electrospinning , and nanofibers having different diameters are provided substantially without time delay as in the embodiment of the present invention. When a mechanical load is applied to the laminated structure, an orderly nanofiber mat is formed that exhibits strong strength and cannot distinguish between the layers.

  Comparing Example 12 and Example 13, it can be seen that the nanofiber structure produced using the embodiment according to the present invention has excellent strength and excellent structure.

(Example 14)
In order to show that when using the system of the present invention and / or applying the method, the effect can be obtained substantially independent of the electrospinning solution used, the above experiments were conducted using the following polymers: And repeated. Polystyrene, polycaprolactone, polyacrylonitriles, polyethylene oxide, polylactic acid, polyacrylic acid, polyesteramide, polyvinyl alcohol, polyimide, polyurethane, polyvinylpyrrolidone, collagen, cellulose and related compounds, chitosan, methacrylic resin, silk, nano Fiber-containing metals, polyethylene vinyl alcohol copolymers, and polyethylene vinyl acetate copolymers. Similar results and effects were found.

  In another form, the invention relates to a wound dressing device for controlling liquid near at least one wound, such as exudate from the wound. Controlling the liquid can include controlling the amount of liquid present near the wound. Controlling the liquid near the wound can include controlling the lateral flow of the liquid near the wound. Controlling the liquid can include absorbing liquid from at least one wound. The wound dressing device is particularly suitable for burn wound dressings, but the invention is not limited thereto. The wound dressing device includes a nanofiber structure that includes a plurality of fibers. The nanofiber structure may be manufactured using any method in the form described herein. The nanofiber structure may be the same as or similar to any of the embodiments or forms of nanofiber structures described herein. The nanofiber structure includes a contact surface that contacts the wound. In order to control the absorption of liquid from the wound and / or the release of liquid into the wound, the fiber diameter of the nanofiber structure varies in a direction perpendicular to the contact surface. Such changes are different fiber diameters between different layers in a multi-layer structure and / or are continuous changes in fiber diameter. The change is a change in porosity, a change in fiber diameter, and / or a change in fiber density. In certain forms, changes in porosity, fiber diameter, or fiber density follow a predetermined change profile to provide a predetermined absorption and / or release profile of exudate by the wound dressing device. . The profile may be such that it quickly absorbs on the side of contact with the wound wound dressing device and moves quickly on the opposite side to substantially dry the wound.

  In another profile, it was absorbed at the contact side between the wound and the wound dressing, moved to a predetermined depth, and previously absorbed and stored in the wound dressing device when less fluid was released by the wound Liquid may be released to the wound. The wound dressing device may, for example, have a profile with a large fiber diameter at the wound contact surface, a small fiber diameter at the middle part of the wound dressing device, and a large fiber diameter again at the opposite surface. In this profile, the wound dressing device comprises a central container of liquid that is later released back into the wound, for example to prevent the wound from drying out too much.

  The nanofiber structure preferably has a porous structure. The structure has a porosity of, for example, an average porosity of at least 65%. The porosity may be, for example, an average porosity of between 65 and 99%, preferably between 70 and 98%, more preferably between 75 and 95%. The nanofiber structure may be capable of absorbing water, a solution, a compound, a gel, for example, 1 to 25 times its own weight. For example, it may have a liquid absorption capacity of 3 to 25 times, preferably 4 to 25 times, more preferably 5 to 25 times its own weight in the case of a liquid with a density of about 1 kg / l.

  In the embodiment according to the present invention, high absorbency is realized exclusively by the structure having a high porosity. In certain embodiments according to the present invention, the nanofiber structure may include an active liquid absorbing and / or gel forming compound to further improve absorption performance. With such active liquid absorption and / or gel-forming compounds, a liquid absorption capacity of 1 to 70 times its own weight can be realized. Such active liquid absorbing and / or gel-forming compounds may be provided, for example, to coat individual nanofibers. Gel forming compounds may also be added to the nanofiber structure in different ways. An example of an active liquid absorbing and / or gel-forming compound may include, but is not limited to, polyacrylic acid.

  The pore size may vary from 30 nm to 8 μm. In some embodiments of the invention, the pore size of at least one section of the nanofiber structure is selected to be less than 150 nm, such as 125 nm, or less than 100 nm. Typical bacteria are larger than 150 nm. Thus, such a structure forms an excellent barrier to prevent the surface from being affected by bacteria once applied to the surface to be treated and / or protected.

  The nanofiber structure may comprise nanofibers having an average diameter of 3 to 2000 nm at least 30%, preferably at least 50% of the nanofibers of the nanofiber structure. The nanofiber cloth structure is disposed on a substrate and has an average thickness of 1 μm to 5000 μm, preferably 1 μm to 2000 μm, more preferably 10 to 2000 nm, more preferably 3 to 800 nm, and even more preferably 10 to 700 nm. . The diameter of most of the fibers (that is, 50% or more of the fibers) contained in the fiber structure of the present invention has a diameter of 3 nm or more, preferably 10 nm or more. As appropriate, the majority (ie, 50% or more) of the fibers contained in the fiber structure of the present invention may have a diameter of 2000 nm or less, preferably 800 nm or less, more preferably 700 nm or less.

  In the present application, a fiber having a diameter in any one of the above-mentioned diameters or in any range is referred to as a nanofiber, and a structure related to the fiber is referred to as a nanofiber structure. In an embodiment, the invention also relates to a fiber structure, wherein the fiber thickness is uniform, i.e. the standard deviation of the thickness of the entire fiber structure is 80%, preferably 50%, more preferably Does not exceed 20%. The fiber diameter is determined by the distance between the discharge part and the receiving surface. The profile of the relationship between fiber diameter and distance is specific to polymers and solvents. Thus, the profile is determined after examining a polymer solution or melt that is specific to the polymer and solvent because it is specific to the polymer and solvent. It may be determined as a result of trial and error through experimental results, theoretical models and the like. The nanofiber has a length between 10 μm and 50 m.

  The nanofiber structure includes at least 50% linear fibers. The straight fiber has a substantially straight portion longer than at least 5 μm. The strength of the fiber is estimated from image analysis, for example. Preferably, the majority (ie 50% or more) of the fibers contained in the fiber structure are linear, ie consist of a substantially linear main part (ie 50% or more) longer than 5 μm. By being substantially linear, the main axis of the fiber, ie the direction along the direction of the fiber, is less than 45 °, less than 30 ° for a length of 10 micrometers in which the change in angle is measured, It changes at an angle less than 15 ° or less than 5 °. This angle is the maximum angle measured between the tangents at two points of the fiber length principal axis. The standard deviation of linearity in the length direction does not exceed 5%.

  As a preferred feature, the fibrous structure of the present invention contains little or no tolerance coupling. That is, the majority (ie 50% or more) of the fibers of the microfiber or nanofiber structure are substantially non-cross-linked. They preferably do not cross bond with adjacent fibers. Cross-bonding does not mean that two fibers are in contact, but means that a bond occurs between the two fibers. This is a result of the spacing between the discharges being at least 1 cm, for example at least 4 cm. Without being bound by theory, it is believed that this can facilitate the evaporation of the solvent during fiber production and thus accelerate the evaporation. If the space between the discharge sections is shorter than 1 cm, the solvent takes a very long time to evaporate the solvent during fiber production. This results in the fusion of adjacent fibers and thus cross-bonding. When the fiber structure is produced from melt, the problem is that the influence of heat cannot be ignored when the discharges are close to each other. Fiber formation will not be sufficient and an intermediate phase between the melt and solid will be included, thus producing cross-linked fibers. The nanofiber structure includes at least 50% randomly oriented fibers. In one embodiment, the fibrous structure forms a mat.

The nanofiber structure is preferably produced through electrospinning of the material. Fibers having the characteristics as described are produced by a multi-nozzle system electrospinning technique. The nozzles are separated by a mutual distance of at least 1 cm, preferably by a mutual distance of at least 4 cm.

  The majority of the material is used to produce nanofiber structures from any of the polymers belonging to the following categories: Polyamide, polystyrene, polycaprolactone, polyacrylonitrile, polyethylene oxide, polylactic acid, polyacrylic acid, polyesteramide, polyvinyl alcohol, polyimide, polyurethane, collagen, cellulose and related compounds, chitosan, methacrylic resin, silk, polyethylene Metals including vinyl acetate copolymer, polyethylene vinyl alcohol copolymer, polyvinyl butyral, and nanofibers.

The wound dressing may have any suitable shape. They are square or rectangular, but may be cut into other shapes depending on the requirements of the envisaged application scene. The surface area may vary from 5 mm ² to 10 m ² . The wound dressing device is suitable for covering small or large wounds, and the nanofiber structure has a contact surface of at least 30 cm × 30 cm, preferably 40 cm × 40 cm, more preferably 50 cm × 50 cm. However, it may be used to cover small scratches and the nanofiber structure has a contact surface of 2 mm × 2 mm, or 5 mm × 5 mm, preferably 20 mm × 20 mm. The wound dressing device may be appropriately cut by hand or using an instrument that cuts mechanically, thermally, or by laser. The thickness of the device is typically measured in a direction perpendicular to the contact surface, but between 100 nm and 30 cm, for example between 50 μm and 5000 μm.

  The nanofiber structure of the wound dressing device is secured to the substrate. The substrate is substantially larger than the nanofiber structure and is adhesive at the ends, eg, with an adhesive, to secure the wound dressing device to the skin around the wound. Alternatively or additionally, such tackiness may be provided directly at the end of the nanofiber structure, whether or not it comprises a substrate. While not limiting, the present invention has been described in a plurality of embodiments by way of illustration, wherein selective features and utility of embodiments according to the present invention have been shown.

  In the first specific embodiment, the wound dressing device described above has been described. In these wound dressing devices, the diameter of the nanofiber structure is controlled and varied as a function of the depth of the nanofiber structure. Excellent and controllable liquid and / or (bio) active compound absorbency by changing the diameter of the nanofiber structure in the depth direction of the nanofiber structure, ie perpendicular to the contact surface of the wound dressing device Can be realized. The fibers may be made from the same material throughout the nanofiber structure, or they may be made from different materials.

Preferably the nanofiber structure is produced through electrospinning of the material. Fibers with the described characteristics are produced by electrospinning technology with a multi-nozzle system. The nozzles are separated from each other by at least 1 cm, such as at least 4 cm or at least 6 cm. Furthermore, the distance between the nozzle and the receiving surface is set in order to control the diameter. While not limiting the present invention, by way of example, a plurality of electrospinning methods with variable diameters for producing a wound dressing device have been described. For the production of a wound dressing device, in a first device using the electrospinning method, the distance between the nozzle and the collecting unit surface of the electrospinning apparatus electrospinning device, change during the process, whereby the individual The diameter of the nanofiber changes. This is shown in detail in FIG.

FIG. 17 shows a portion of the electrospinning apparatus 100, which comprises a set of nozzles 102 and a collector surface 104. A voltage is applied between the nozzle 102 and the collecting unit surface 104 using, for example, a power source (not shown). The relative position of the nozzles moves in all directions, thereby allowing proper overlap between the different fibers that are produced. Further, the system is provided to provide a change in distance between the nozzle discharge and the collector surface. FIG. 17 also shows a conical injection region 106 where the material is injected. The collector surface 104 is at least part of the moving surface. In the second device, changes in nanofiber diameter are produced by forming a laminated structure of layers. Each layer is produced with a constant nozzle-collector surface distance. This is shown in detail in FIG.

FIG. 19 is an apparatus similar to FIG. 17, in which the distance between the nozzle discharge unit 102 and the collection unit surface 104 of the electrospinning apparatus 200 due to the movement of the nozzle discharge unit 102 is not provided. However, it includes a plurality of nozzle discharger sets 202a, 202b, 202c provided at different distances with respect to the collector surface 104. The parameter for electrospinning is determined, for example, by experiment, for example, from the viewpoint of the distance from the nozzle discharge unit to the collection unit. The optimum applied voltage provides important advantages in principle when the distance between the nozzle discharge and the collector changes, and other parameters such as the material flow rate are also adjusted. Other parameter adjustments are made in other suitable ways, according to predetermined rules, according to the calculation model, by trial and error. Until a steady state is reached, optimization is performed, for example by adjusting the parameters. The steady state is defined by the point that the tailor cone is constant and the electronic rotation is continuously performed. The tailor cone is a typical triangular shape that occurs when a drop of polymer solution is dropped into an electric field. Such steady-state detection is performed visually or optically using an optical detector, and parameter adjustment is performed manually or automatically or partially automatically.

  According to the example of the present embodiment, the nanofiber structure has a small-diameter nanofiber between 3 nm and 1.5 μm on one side, for example, a large size of 50 nm to 5 μm on the other side which is a contact surface. Produced to have a diameter. With the first device, a continuous or quasi-continuous nanofiber diameter change can be obtained as a function of depth, and a corresponding wound dressing device is shown in FIG. In the second device, multiple discrete steps can be obtained in the change in diameter, and a corresponding wound dressing device 250 is shown in FIG. In a preferred embodiment, the fiber diameter of the nanofiber structure gradually decreases from the contact side of the wound dressing device to its opposite side.

  In embodiments of the invention, the pore size is small, thereby allowing effective evaporation of the liquid absorbed by the structure due to the high specific surface area of the nanofiber structure. The most effective evaporation properties are realized on one side of the device where nanofibers with the smallest diameter are present. This is because the highest peculiar surface area is formed on the side portion, and the amount of liquid transported to the surface is the maximum.

  In another preferred embodiment of the invention, the wound dressing device is not only capable of absorbing a large amount of liquid on one side and evaporating liquid on the other side (e.g. liquid oozes). Effectively transfer the liquid absorbed on one side (contact side or contact surface) of the wound dressing device (for wounds) to the other side of the structure under conditions where the device is properly used It can also be made. The condition is that the wound dressing is arranged so that the nanofibers with the largest diameter are on the contact surface and the nanofibers with the smallest diameter are on the anti-firing side of the contact surface. This means that the nanofiber diameter should be reduced from the liquid absorption side to the liquid release side in the device cross section.

In the embodiment according to the present invention, in one electrospinning session, since it is possible to provide a wound dressing device according to electrospinning, the adhesive between the different fibers are sufficiently strong to create a rigid structure For example, it does not become a cross-linked fiber. In particular, by placing adjacent layers of fibers when the previously placed layer is still wet (eg containing 2 to 6% moisture), the different fibers tend to bond slightly together. The bond is a weak bond, not a chemical bond or a cross bond. In an embodiment according to the present invention, the fiber structure of the wound dressing device can be changed during the same electrospinning session while at the same time a fiber structure without balls is obtained. This can be achieved, for example, by changing the nozzle-collector distance and simultaneously controlling different parameters during the electronic rotation session.

  In an embodiment according to the present invention, the wound dressing device can provide a wound dressing device that can effectively absorb liquid from a surface (for example, a wound from which the liquid exudes), and can effectively absorb the liquid. Dynamic liquid removal can be established based on the effective movement of the liquid in the cross section and the effective release by evaporation on the other side of the device. Furthermore, in the embodiment, the liquid absorbed early is discharged and returned to the wound when the liquid formation process is completed. As can be seen from these three advantages, the liquid removal characteristics of the device make it possible to keep the liquid discharge surface substantially dry or in a steady state with a predetermined amount of liquid on the wound surface. In other embodiments, the device is suitable to prevent the wound from drying out. An example of such a wound dressing device is shown in FIGS. The figure shows a wound dressing device arranged to absorb and accumulate liquid from a wound and later release it back into the wound. FIG. 22 shows a corresponding wound dressing device 400. There, production is possible using the system shown in FIG. 17, and the diameter changes continuously. FIG. 24 shows a laminated structure 450 that can be produced using the system shown in FIG. Both structures have an intermediate position in a direction perpendicular to the contact surface fibers that has a diameter that is less than the diameter of the fibers near the contact surface and a diameter that is less than the diameter of the fibers near the opposite surface of the contact surface. In the apparatus according to FIG. 24, an intermediate layer having such fibers is provided. In such embodiments, these allow the amount of liquid near the wound to be controlled and the wound is dry. Therefore, it is useful for certain types of wounds.

  In a second specific embodiment, the nanofibrous structure further avoids or reduces the risk that adjacent wounds treated with the same dressing will infect each other due to a small cut by the wound dressing device. To be provided. Such inconvenience occurs when one of the wounds is infected before the device is applied. In the present embodiment, by using the above-described nanofiber structure, a pattern is formed on at least the upper portion of the nanofiber structure, that is, a portion facing the scratch. An example of the structure 300 on which a pattern is formed is shown in FIG. 21, but the present invention is not limited to this. Different types of patterns may be used.

  The shape of at least the top portion of the nanofiber structure is formed such that the surface of the wound dressing device for contacting the wound is in discrete contact in multiple regions. The size of these regions may be the same or different in all regions. The preferred dimensions of the individual regions are 5 cm × 5 cm, preferably 2 cm × 2 cm, more preferably 1 cm × 1 cm. The pattern of the nanofiber structure or part thereof is produced in a suitable manner, for example by treatment with heat according to the pattern formed. For example, a heated pattern structure may be used to form such a pattern in a nanofiber structure or part thereof. Since the nanofibers are locally melted and fixed to each other by heat, the pattern is thermoformed. In those parts it will be clear that the structure reduces the properties of the nanofiber. At these boundaries, liquid cannot easily move from one area in the pattern to an adjacent area, thereby reducing the infected wound liquid in one wound area from contacting another wound area. Or it becomes possible to avoid. In other words, a barrier is formed to avoid lateral flow of the wound liquid. It is desirable to keep healthy skin dry, and the lateral flow barrier can also prevent the flow of wound liquid from moving to healthy skin near the wound. The lateral flow barrier of the nanofiber structure can also be used for a nanofiber structure in which there is no change in fiber diameter in the depth direction of the nanofiber structure, that is, in the direction perpendicular to the contact surface of the nanofiber structure.

  In a nanofiber structure according to certain embodiments of the present invention, liquid cannot move from a patterned area to a different area, and parts that are relatively close to each other are not wetted by one liquid emission source. This means that, for example, in the case of a burn, exudate cannot move to an adjacent area even if it is treated with the same device, so that the burn is not infected by an adjacent burn.

  As described in the first embodiment, the pattern layer (in contact with the surface to be treated) can be combined with a normal layer. Due to the normal layer spreading and evaporating relatively easily, the moisture of the wound in the pattern layer is negligible. This combination can prevent cross-infection of the wound and the normal layer can provide not only evaporation to easily release moisture from the nanofiber structure, but also great moisture absorption performance. The movement of liquid from the patterned layer to the non-patterned region does not return to the patterned layer due to the change in nanofiber diameter. The diameter of the nanofiber decreases along the cross section from the liquid absorption side (which contacts the pattern layer) to the side where the liquid is released by evaporation. Instead, by using an intermediate non-patterned area with a large fiber diameter, it is possible to accumulate liquid at the pattern portion of the pattern layer and maintain a steady state where a given liquid is present on the wound surface In some cases, it is possible to discharge the liquid back to the wound as appropriate. An example of a wound dressing device 350 according to this principle is shown in FIG.

  The liquid barrier may be used to prevent excessive movement of liquid from the wound dressing device. By using such a pattern, the ability to retain the liquid released by the wound in the coating for later return to the wound can be improved. Thereby, a steady state in which a predetermined liquid is present on the wound surface can be maintained. This has been found to be desirable for wound healing processes and changes through investigations at the wound burn centers in Europe.

  In a third particular embodiment, the nanofiber structure described in any of the above embodiments is disclosed, further comprising an antibacterial and / or biocidal property of the nanofiber structure. Is added. Thereby, the nanofiber structure can preferably provide an antibacterial and / or biocidal action, particularly when the surface to be treated is infected before applying the structure. Useful. Since the pore size of the nanofiber structure is small, the bacteria may remain in the wound and may not be able to absorb the bacteria due to the pore size.

According to embodiments of the present invention, antibacterial and / or biocidal properties may be realized by providing a nanofiber layer having antibacterial and / or biocidal properties. Such a layer is realized by coating the nanofibers with antibacterial and / or biocidal materials or by electrospinning fibers of such materials. A layer of nanofiber containing such material is preferably placed on the liquid-absorbing side and this layer is in direct contact with the surface to be treated. The layer may include in the nanofiber an active compound having antibacterial and / or biocidal properties, such as polyvinyl pyrrolidone (PVP) with I2, for example. When applied to the surface, the fiber does not dissolve in the liquid released from the surface, thereby activating the envisaged bactericidal compound. Desirable embodiments add multiple nanofibers having antibacterial and / or biocidal properties, thereby prolonging the antibacterial and / or biocidal effect. This can be achieved by such a layer placed away from the wound being delayed in time and taking on antibacterial and / or biocidal properties.

  In another form, the invention relates to the use of nanofiber structures as described in the embodiments of the invention for use in wound dressings. As described above for the first form of device, its use can provide one or more different features and utilities.

  In yet another aspect, the invention relates to a method for a wound dressing. The method includes obtaining a nanofiber structure having a contact surface in contact with the wound, where the fiber diameter varies in a direction perpendicular to the contact surface according to a predetermined profile. The method further includes positioning the nanofiber structure by contacting the nanofiber structure with a wound in a predetermined direction. Other methods may include developing one, multiple or all features of the wound dressing device as described in the first aspect of the invention.

  According to yet another aspect, the present invention relates to a tooth bleaching system for bleaching teeth. The system for bleaching teeth includes two parts. The first portion includes a nanofiber structure. The second part includes a tooth bleaching part having a bleaching agent. The nanofiber structure is used to hold the tooth bleach while using the system to bleach the teeth. In other words, the nanofiber structure becomes a carrier for the tooth bleaching part in use. The nanofiber structure may be provided on a plurality of teeth to whiten the teeth, and this is referred to as tooth bleaching. The structure of the nanofiber structure is provided to adequately absorb, hold and release tooth bleaching parts having a viscosity between 10 cps and 1000 cps, preferably 10 cps to 400 cps, more preferably 10 cps to 199 cps. The nanofiber structure may be produced using any of the methods as described in other aspects of the invention. The nanofiber structure may be the same or similar to any of the nanofiber structures described in the embodiments or embodiments of the present invention.

The nanofiber structure is supported by the base layer, but the present invention is not limited thereto. The material of the base layer is suitably suitable for use in the mouth. Such a material can be in the form of teeth, such as an aluminum foil. This is because such a material is suitable for arranging nanofibers by electrospinning , and can maintain the shape even after being bent so as to cover the teeth. The nanofiber structure itself may be provided in a structure that can retain its shape when provided on the teeth.

  The nanofiber structure may be provided to fit a plurality of teeth, such as a row of front teeth. The nanofiber structure may be involved to exert an adhesive effect between this layer and the tooth surface based on the contact area. The nanofiber structure may be applied to a structure for providing the adhesion of the device on the tooth. The tooth to be treated may include incisors. Preferably, the structure is applied to treat canines as well as incisors. In a preferred embodiment, the structure may be applied to cover the tip of the canine with, for example, an incisor covering. The nanofiber structure may be secured to the front surface of the tooth using the first portion and to the back surface of the tooth using the second portion. Referring to FIG. 25, which shows an example of a first part of a system that combines substrates appropriately coated with, for example, a nanofiber structure. The first side of the first portion of the device is cut into a triangle, thereby allowing the first portion of the device to bend and fit the remaining area on the back of the tooth. The entire area of the first part of the device is applied to the front part of the tooth. Initially, the first part of the device is flat, but when applied to a tooth, it is bent and fully adapted to the shape of the tooth. The feature of being able to bend over the teeth and adapt the triangular shape to the back part and perfectly match the tooth shape is that the nanofiber layer is very porous, compressible and fluffy It can be obtained through the feature of having the structure as described above, whereby it becomes possible to cover the circumference of each tooth according to its shape.

  The device has a length between 0.5 and 15.0 cm, more preferably 2 to 10 cm, most preferably 4 to 8 cm, 0.3 to 5.0 cm, more preferably 0.5 to 4 cm, Most preferably it has a width between 1 and 3 cm. In order to bend easily and fit the first part of the device onto the teeth, it is cut into a triangle on one side of the first part of the device. These triangular incisions in the first part of the device have a depth between 0.1 and 2.0 cm, more preferably between 0.3 and 1.5 cm, most preferably between 0.5 and 1 cm. .13 to 2.5 cm, more preferably 0.4 to 2.0 cm, most preferably 0.7 to 1.3 cm. In other embodiments, the ends of the stripe are rounded so as not to damage the mouth. The device may have other suitable shapes.

  Nanofiber structures include nanofibers such that at least 30%, preferably at least 50% of the nanofiber structures have an average diameter of 3 to 2000 nm. The nanofiber fabric structure is disposed on the substrate and has an average thickness between 1 μm and 5000 μm, preferably between 1 μm and 2000 μm, preferably between 10 μm and 2000 μm, preferably between 3 and 800 nm, more preferably between 10 and 700 nm. The diameter of most of the fibers (that is, 50% or more of the fibers) contained in the fiber structure of the present invention is 3 nm or more, preferably 10 nm or more. As a feature that is added as appropriate, the majority of the fibers (ie, 50% or more of the fibers) contained in the fiber structure of the present invention have a diameter of 2000 nm or less, preferably 800 nm or less, and most preferably 700 nm or less.

  Herein, fibers having a diameter within one of the listed diameters or in the range of diameters are referred to as nanofibers, and the corresponding structures are referred to as nanofiber structures. In an embodiment, the present invention relates to a fiber structure having a uniform fiber thickness. That is, the standard deviation of the thickness of the entire fiber structure does not exceed 80%, preferably 50%, more preferably 20%. The fiber diameter depends on the distance between the discharge and the receiving surface. The profile of the relationship between fiber diameter and distance is specific to polymers and solvents. Since the profile is specific to the polymer and solvent, the profile can only be determined by examining the polymer solution or melt. It is determined by trial and error, by experimental results, by a theoretical model, and so on. Each of the nanofibers has a length of 10 μm to 50 m.

The fiber material may be any suitable material, for example, polyamide, polystyrene, polycaprolactone, polyacrylonitriles, polyethylene oxide, polylactic acid, polyacrylic acid, polyesteramide, polyvinyl alcohol, polyimide, polyurethane. Collagen, cellulose and related compounds, chitosan, methacrylic resin, silk, polyethylene vinyl alcohol copolymer, polyethylene vinyl acetate copolymer, polyvinyl butyral, and nanofiber-containing metals. The nanofiber structure may include fibers comprising a pH adjusting material as described herein. Other components of the device may be produced in a nanofiber structure, for example obtained by electrospinning a specific nanofiber. The nanofiber structure may include fibers made of polyamide produced by electrospinning using a mixture of formic acid and acetic acid. The ratio of formic acid to acetic acid is between 90/10 and 10/90 weight percent, preferably between 30/70 and 70/30 weight percent, more preferably between 40/60 and 60/40 weight percent. Preferably, it may be 50/50 weight percent. If it is 50/50 weight percent, steady production and high flow rates can be achieved in steady state.

  The structure may have a porosity of, for example, an average porosity of at least 65%. The porosity, for example the average porosity, is between 65 and 99%, preferably between 70 and 98%, more preferably between 75 and 95%. The pore size may vary from 30 nm to 8 μm. For example, the nanofiber structure can absorb 3 to 12 times its own weight of water, solution, and gel compound.

  The nanofiber structure includes at least 50% straight fibers, and the fibers include substantially straight portions that are at least longer than 5 μm. The linearity of the fiber is estimated from image analysis, for example. Preferably, the majority (ie 50% or more) of the fibers contained in the fiber structure are linear, ie consist of a substantially linear main part (ie 50% or more) longer than 5 μm. By being substantially linear, the main axis of the fiber, ie the direction along the direction of the fiber, is less than 45 °, less than 30 ° for a length of 10 micrometers in which the change in angle is measured, It changes at an angle less than 15 ° or less than 5 °. This angle is the maximum angle measured between the tangents at two points of the fiber length principal axis. The standard deviation of linearity in the length direction does not exceed 5%.

  As a preferred feature, the fibrous structure of the present invention contains little or no tolerance coupling. That is, the majority (ie 50% or more) of the fibers of the microfiber or nanofiber structure are substantially non-cross-linked. Because it is non-crosslinked, it does not include a covalent bond between the polymer chain of one fiber and another polymer chain of an adjacent fiber. The distance between the three or more outlets is provided so that a fiber structure containing at least 50% fibers that are substantially free of chemical bonds can be produced. They are preferably not cross-linked with adjacent fibers. Cross-bonding refers to the formation of a bond between two fibers, not just two fibers in contact. This is a result of the spacing between the discharges being at least 1 cm. Without being bound by theory, it is believed that this can facilitate the evaporation of the solvent during fiber production and thus accelerate the evaporation. If the space between the discharge sections is shorter than 1 cm, the solvent takes a very long time to evaporate the solvent during fiber production. This results in the fusion of adjacent fibers and thus cross-bonding. When the fiber structure is produced from melt, the problem is that the influence of heat cannot be ignored when the discharges are close to each other. Fiber formation will not be sufficient and an intermediate phase between the melt and solid will be included, thus producing cross-linked fibers. Relatively weak physical relationships such as van der Waals forces or hydrogen bonds are not included in the definition of cross bonds. The nanofiber structure includes at least 50% randomly oriented fibers. In one embodiment, the fiber structure forms a mat.

Preferably, the nanofiber structure is produced by electrospinning the material. Produced through electrospinning of materials. Fibers having the characteristics as described are produced by a multi-nozzle system electrospinning technique. The nozzles are separated by a mutual distance of at least 1 cm, preferably by a mutual distance of at least 4 cm. Furthermore, the distance between the nozzle and the receiving surface is set in order to control the diameter. By changing the distance during electrospinning , the fiber diameter of the nanofiber structure can be changed. In view of the change in the distance between the discharge part and the collection part, other parameter changes for electrospinning , such as applied voltage, are determined empirically, for example.

  In particular embodiments according to the present invention, the nanofiber structure may have porosity, fiber diameter, or one or more longitudinal directions (eg, in the depth direction of the nanofiber structure, ie, in cross-section, and / Or has a change in the density of the fibers (in a given direction along the surface of the nanofiber structure, ie along the surface of the nanofiber structure suitable for contact with the teeth). Changes in porosity, fiber diameter, or fiber density follow a predetermined change profile to provide a predetermined release profile of the tooth bleaching part or bleach. The change is realized by the characteristics of the method as described in the other aspects described above, so that the nanofiber structure is a feature of the nanofiber structure described in the embodiments according to the other aspects of the specification. One, plural or all of

  In one example, the porosity of the nanofiber structure increases from the base contact side to the tooth surface contact side. The change in porosity, fiber diameter or fiber density is continuous or stepwise. In one example, such a change is achieved by using a laminated nanofiber structure comprising at least two layers of nanofibers having different diameters.

  The predetermined profile for density, porosity, or diameter provides a predetermined amount of release for tooth bleach release. It is useful for providing a treatment according to a predetermined profile, for example using uniform bleach release. Other profiles may be provided. For example, at the beginning of the first 4 minutes, for example, most of the bleach (eg, about 40% to 50%) is released, and thereafter, the remainder is released over a long time, eg, 9 minutes. In one aspect, the invention relates to the nanofiber structure described in the embodiments of the invention for use in tooth bleaching. The same features and utilities relating to the nanofiber structures described in these embodiments may be applied to this aspect of the invention.

  As mentioned above, the tooth bleaching section contains a bleaching agent, which is an active component for bleaching teeth or teeth, or contains such components or releases such components or It is a substance that can be generated. A bleaching agent, also referred to as a bleaching element, is a peroxide such as hydrogen peroxide, hydrogen peroxide product, calcium oxide, or combinations thereof. Bleaching agents are carbamide peroxide, perborate, percarbonate, oxoacids and / or combinations of these chemicals. For example, the concentration of the bleaching element, such as hydrogen peroxide, is between 0.1 and 35 percent tooth bleaching weight, preferably between 1 and 25 tooth bleaching weight percent, more preferably between 3 and 16 Used in weight percent of teeth bleaching part. For example, a hydrogen peroxide bleaching agent thus has an active component concentration of between 0.1 and 35 weight percent, preferably between 1 and 25 weight percent, more preferably from 3 weight percent. Provided to be between 16 weight percent.

  The tooth bleaching section may include a filling material. The filler material may include one or more of glycerin, sorbitol, polyethylene glycol, or polypropylene glycol.

  The tooth bleaching structure may contain the normal pH adjusting material of a technically standard buffer material, such as sodium hydroxide, hydrogen chloride, sodium phosphate, sodium bicarbonate, sodium stannate, citric acid, citric acid. Although it is sodium acid, it is not limited to these. The pH adjusting material of the tooth bleaching portion may be between 0.1 weight percent and 10 weight percent. In some embodiments, the pH adjusting material is provided directly in the tooth bleaching section. Often, the continuous degradation of the bleach during activation depends on the pH of the tooth bleaching area. A pH adjusting material is added to properly activate the bleach. When the pH adjusting substance is provided directly in the tooth bleaching portion, there is a trade-off between hardly activating the bleaching agent during storage and sufficiently activating the bleaching agent during use. Such a trade-off shortens the expiration date of the tooth bleaching product or at least shortens the period during which the system is effective.

  According to a preferred embodiment of the present invention, the pH-adjusted product and the bleaching agent are separated and conveyed. When the bleaching agent is stored, the pH of the tooth bleaching portion where the bleaching agent is held is selected so as to have a low decomposition rate, for example, a pH of about 5. As a result, the bleach is very stable. When the pH adjusting substance is mixed during preparation for use or during use, the pH of the tooth bleaching part changes to 7.5-8.0 depending on the function of the pH adjusting substance. This occurs, for example, when a tooth bleaching material is absorbed into a nanofiber structure with a pH adjusting material. At this pH, the bleach is not stable but is very activated for bleaching. Accordingly, it is preferable to use a pH of about 7.5 for bleaching and a pH clearly lower than 6 for storage.

A method of solving storage problems is provided in one embodiment, where the pH adjusting material is on the nanofiber structure or, if there is a substrate carrying the nanofiber structure, It is provided in powder form on the substrate. Alternatively or additionally, the bleaching agent may be separated and provided on the nanofiber structure or the substrate that supports the nanofiber structure. In a further preferred embodiment, a pH constituent may be provided on the fibers of the nanofiber structure. This can be accomplished, for example, by adding an appropriate amount of pH adjusting material to a solution for producing nanofiber structures, such as an electrospinning solution. In this case, the different operations to be performed by the user are limited, and different components to be stored separately before use or preparation thereof can be limited or reduced.

  The tooth bleaching part may be a gel. It contains a gel forming material. The gel-forming material is less than 0.1 weight percent of the tooth bleaching portion, for example 0.09 weight percent of the tooth bleaching portion. The gel-forming material comprises any or combination of cellulose carboxymethylcellulose, carboxypropylcellulose, gum, poloxamer, or carboxypolymethylene. A preferred embodiment according to the present invention reduces or prevents the occurrence of leakage by using a gel. Thus, the user can use it comfortably. For example, inflammation that occurs in a part of the mouth around the teeth can be reduced.

  The tooth bleaching unit may include a taste substance in order to improve the taste when tooth bleaching is performed. An example of such a gustatory substance is spearmint / peppermint. According to the embodiment of the present invention, the viscosity of the tooth bleaching part can be made relatively low. The viscosity is 10 to 1000 cps, preferably 10 cps to 400 cps, more preferably 10 cps to 199 cps. According to embodiments of the present invention, a method and system can be provided that includes a tooth bleaching section having a relatively low viscosity due to the liquid absorption and release characteristics of the nanofiber structure. According to the embodiment of the present invention, it is possible to limit, reduce, or prevent the risk of leakage from the structure onto, for example, the gums or palate in the mouth. Alternatively, an aqueous solution rather than a gel may be used and immobilized on the nanofiber structure. Furthermore, the low viscosity improves the flowability of the bleaching material in the gel and makes the release of the bleach to the teeth more effective.

  The dental bleaching system includes components that protect the gingiva or palate and is a chemical for protecting the gingiva or palate, such as Gantres®, but the invention is not so limited.

  In the practice of the present invention, the tooth bleaching system may be a kit provided to separate and hold the nanofiber structure and the tooth bleaching section prior to use. If the pH-adjusting substance is provided in the nanofiber structure, i.e. at least separated from the tooth bleach, it is possible to perform bleaching at an optimum pH where the high effect of the bleach is obtained. The tooth bleaching system may itself be packaged in a blister that is used as a soaking tray for soaking the nanofiber structure in the tooth bleaching section.

  The device may be delivered to the user in two parts. One part is a nanofiber structure containing a pH adjusting substance, and the other part is a tooth bleaching part.

  In yet another aspect, the present invention relates to a method for performing tooth bleaching. The method according to embodiments of the present invention may include using both the nanofiber structure and the tooth bleaching section to perform tooth bleaching. The method can be used at the appropriate place depending on the consumer's choice, i.e. not only at the dental clinic but also at home, for example. According to this method, it is possible to achieve tooth bleaching with an excellent aesthetic effect. As described in the first embodiment of the present invention, the method is performed using the tooth bleaching system, but the present invention is not limited thereto. The tooth bleaching section may be packaged with the nanofiber structure in one full package, but it is preferred that the tooth bleaching section is preferably not in direct contact with the nanofiber structure during storage. The nanofiber structure and / or the tooth bleaching section may be packaged in a container into which the tooth bleaching section has been poured. Such a package may be sealed by a plastic or paper film. The tooth bleaching part is provided in the sealed first container. The method may include providing a tooth bleaching section in a container provided to immerse the nanofiber structure in the nanofiber structure prior to immersing the nanofiber structure.

  The method according to an embodiment of the present invention includes immersing the nanofiber structure in a tooth bleaching section. In order to immerse the nanofiber structure, the nanofiber structure is placed in a container comprising the nanofiber structure facing the tooth bleaching part. The method may further include initial contact of the pH adjusting material and the bleaching agent while soaking the nanofiber structure.

  According to an embodiment of the present invention, the method also includes applying the soaked nanofiber structure to the teeth for a predetermined time and then removing the nanofiber structure. Applying the soaked nanofiber structure may also include applying the nanofiber structure shape to the tooth shape. By using nanofiber structures, the shape of the structure is appropriately applied to the shape of the teeth. The nanofiber structure may have a structure that is fixed to the tooth by the adhesion of the structure due to the surface area of the fibers of the nanofiber structure in contact with the tooth. Applying the nanofiber structure may include pressing the nanofiber structure around the teeth. Applying the soaked nanofiber structure may include applying the nanofiber structure to the incisors and canines to cover the canine tips. This makes it possible to bleach uniformly, and it is possible to bleach a plurality of teeth, for example, incisors and canines simultaneously. In some embodiments according to the present invention, when applying a soaked nanofiber structure, the tooth bleaching section is controlled, eg, the flow rate to the teeth is controlled and opened. This is achieved, for example, by using nanofiber structures with different diameters, porosities or fiber densities used. The method according to an embodiment of the present invention may further include one or more steps of developing the function of one or more components of the tooth bleaching system described in the first embodiment.

  For example, examples according to the embodiment of the present invention are as follows, but the present invention is not limited thereto. The method for bleaching teeth is a method using a tooth bleaching system as described in the first embodiment. The tooth bleaching system in this example includes a nanofiber structure disposed on a substrate, and in this example a tooth bleaching section, which is a tooth bleaching gel in a plastic or glass container. The amount of tooth bleaching gel is 1 to 2 ml. In this embodiment, the two components are held in a plastic blister sealed with a plastic or paper film.

  According to an exemplary method, the blister is opened and the nanofiber structure and tooth bleach are removed from the blister. The plastic or glass container is opened and the tooth bleaching section is poured into blisters used as trays. Next, in this embodiment, the nanofiber structure disposed on the substrate is disposed in a blister. This is preferably done by providing the nanofiber structure toward the tooth bleaching section while providing the substrate away from the tooth bleaching section. The tooth bleaching part is thus absorbed by the nanofiber structure. This process is completed in 2 to 5 minutes.

  During the absorption of the tooth bleaching section, preferably the initial contact between the tooth bleaching agent and the pH adjusting material is separated by the presence of the pH adjusting material first in the nanofiber structure or from the tooth bleaching section. May be realized by being stored and provided to the nanofiber structure prior to initiating absorption. During soaking, the tooth bleach may mix with the pH adjusting material, thereby raising the pH to about 7-9. The nanofiber structure is removed from the blister and the system is then placed on the front teeth with a slight pressure. This arrangement may include covering not only the incisors but also the canines including the tips. Placing may include folding the part on the tooth, for example in a triangle, and securing it to the back of the tooth. This fixation can be performed with little pressure, and the sticking effect is realized by the structure of the nanofiber structure without the addition of a sticking agent. The nanofiber structure disposed on the substrate is maintained on the teeth for a predetermined time. After treatment, the nanofiber structure placed on the substrate is removed by hand, and the teeth are rinsed or brushed with water.

  In yet another aspect, the invention relates to the use of a tooth bleaching system or nanofiber structure according to any of the embodiments described above for application to tooth bleaching. The usefulness and characteristics of the systems and / or structures described above result in the preferred use of such systems and / or structures.

  By way of illustration, embodiments of the present invention are not limited thereto, and many examples of the first specific embodiment are described below.

(Example 15)
The device comprises (1) a nanofiber structure disposed on a substrate having a cross section of 7 × 2 cm, (2) a tooth bleaching gel (1 ml) or solution filled in a plastic or glass container, and (1) And (2) are housed and comprise a plastic or plastic blister sealed with a plastic or paper film. The blister is opened and components 1 and 2 are removed. A plastic or glass container is opened and the gel is poured into a blister. The nanofiber structure placed on the substrate is placed in the bilister so that the nanofiber structure faces the gel (points down). The gel immerses the nanofiber structure. The process is completed in 2 to 5 minutes. While the gel or solution is immersed, it is mixed with the pH adjuster contained in the nanofiber structure. This increases the pH to about 8. The nanofiber structure placed on the substrate is removed from the blister and placed on the front teeth with low pressure. The triangular part is folded over the tooth and is inherently sticky by the nanofiber structure and is therefore fixed to the back of the tooth. A nanofiber structure placed on a substrate and containing a gel is attached to the tooth for 10 minutes. After treatment, the nanofiber structure placed on the substrate is removed by hand and the teeth are rinsed with water and / or brushes. This process is repeated twice a day for 7 days, for example.

An apparatus as described above was tested on 4 subjects according to the procedure described above. Teeth for all subjects at the start, was _{A 3} in hue scale VITA (R). After the treatment of 7 days, shades for all of the teeth, was improved to shades of A _1. It is visually very white than A _3. Even after 6 months, whiteness of A ₁ is maintained.

(Example 16)
Tooth bleaching gel may be used in embodiments of the present invention, such as Example 15 above. It consists of sorbitol 26, glycerol 25, hydrogen peroxide (35% solution) 20, carboxymethylcellulose 0.10, Gantres (R) 2.50, citric acid 0.04, sodium citrate 0.5, spear / peppermint 0. 10 and water 100m / m%. This mixture becomes a 6% hydrogen peroxide solution. The gel is used with the device according to the process as described in the examples and / or embodiments of the present invention.

(Example 17)
Tooth bleaching gel may be used in embodiments of the present invention, such as Example 15 above. It consists of sorbitol 21, glycerol 20, hydrogen peroxide (35% solution) 40, carboxymethylcellulose 0.10, Gantres (R) 3.50, citric acid 0.04, sodium citrate 0.5, spear / peppermint 0. 10 and water 100m / m%. This mixture becomes a 12% hydrogen peroxide solution. The gel is used with the device according to the process as described in the examples and / or embodiments of the present invention.

(Example 18)
Tooth bleaching gel may be used in embodiments of the present invention, such as Example 15 above. It consists of sorbitol 21, glycerol 20, hydrogen peroxide (35% solution) 50, carboxymethylcellulose 0.10, Gantres (R) 3.50, citric acid 0.04, sodium citrate 0.5, spear / peppermint 0. 10 and water 100m / m%. This mixture becomes a 15% hydrogen peroxide solution. The gel is used with the device according to the process as described in the examples and / or embodiments of the present invention.

(Example 19)
Tooth bleaching gel may be used in embodiments of the present invention, such as Example 15 above. It consists of sorbitol 14.5, glycerol 13.9, hydrogen peroxide (35% solution) 66.7, carboxymethylcellulose 0.10, Gantres (R) 2.50, citric acid 0.04, sodium citrate 0.5 , Spear / Peppermint 0.10, and 100 m / m% water. This mixture becomes a 20% hydrogen peroxide solution. The gel is used with the device according to the process as described in the examples and / or embodiments of the present invention.

(Example 20)
Tooth bleaching gel may be used in embodiments of the present invention, such as Example 15 above. It consists of sorbitol 6, glycerol 6, hydrogen peroxide (35% solution) 83.3, carboxymethylcellulose 0.10, Gantres (R) 2.50, citric acid 0.04, sodium citrate 0.5, spear / peppermint 0.10 and water 100 m / m%. This mixture becomes a 25% hydrogen peroxide solution. The gel is used with the device according to the process as described in the examples and / or embodiments of the present invention.

(Example 21)
The examples described in FIGS. 15 and 20 may be used in combination with a nanofiber structure comprising fibers made of polyamide. In that case, electrospinning is carried out using a mixture of 50% formic acid and 50% acetic acid as solvent.

Claims (13)

An electrospinning apparatus for an electrospun fiber structure,
The electrospinning apparatus is
A set of drains (5) for draining the solution or melt;
A receiving surface (8) for receiving discharge from the set of discharge sections (5),
The receiving surface (8) is provided to move in a first direction parallel to the receiving surface (8);
The movement corresponds to the formation of the fibrous structure in the length direction;
The electrospinning apparatus includes a power source for generating a potential difference between the one set of discharge portions and the receiving surface,
The electrospinning device varies the distance between the discharge portion of the device and the receiving surface according to the predetermined profile during electrospinning to form a predetermined fiber thickness profile across the fiber structure. Let
The electrospinning device has a distance between the discharge surface (5) and the receiving surface (8) in a direction perpendicular to the receiving surface (8) for each different discharging portion along the first direction. The electrospinning apparatus is configured to change the distance by providing a predetermined distance profile. The electrospinning device according to claim 1, wherein the predetermined distance profile is to increase the distance profile or to decrease the distance profile. The set of discharge parts (5) comprises at least two parts of discharge parts (5),
Each of said portions of the discharge part (5) is equidistant from said receiving surface (8);
The electrospinning device according to claim 1 or 2, wherein a distance between each part and the receiving surface (8) can be set according to the predetermined distance along the first direction. The electrospinning apparatus according to any one of claims 1 to 3, wherein the one set of discharge portions is provided on a predetermined surface inclined at a predetermined angle with respect to the receiving surface. The said one set of discharge | emission parts (5) are parallel to the said receiving surface (8), and are provided so that it can reciprocate in the direction perpendicular | vertical to the said 1st direction. The electrospinning apparatus according to any one of the above. A method for producing a fiber structure, comprising:
Providing a set of drains (5) for draining the solution or melt;
Providing a receiving surface for receiving discharge from the set of discharge sections (5);
Moving the receiving surface (8) in a first direction parallel to the receiving surface (8);
Providing a potential difference between the set of drains (5) and the receiving surface (8);
Providing a solution or melt to the discharge part (5) while providing the movement and potential difference,
In order to realize a fiber thickness profile that is predetermined based on the dimensions of the fiber structure and that has a fiber diameter difference of less than 10% in any cross section perpendicular to the dimensions , the solution or melt discharge unit Changing the distance between the discharge part (5) and the receiving surface according to a predetermined distance profile,
A predetermined distance for the distance between the receiving surface (8) and the discharging portion (5) in a direction perpendicular to the receiving surface (8) for each discharging portion that varies along the first direction. The fiber structure manufacturing method, wherein the distance is changed by providing a profile. The fiber structure according to claim 6, wherein the change in distance is realized by providing a relative movement of the discharge portion with respect to the receiving surface in a predetermined direction perpendicular to the receiving surface. Body manufacturing method. An electrospun fiber structure comprising fibers,
The electrospun fiber structure extends long in the longitudinal direction ,
The fiber diameter is pre-determined based on the dimensions of the electrospun fiber structure and varies according to a profile in which the difference in fiber diameter in any cross section perpendicular to the dimension is less than 10% ;
The change in the diameter of the fiber according to a predetermined profile is in a direction perpendicular to the receiving surface between the outlet and the receiving surface of the fiber providing a solution or melt for producing the fiber. By providing a change according to a predetermined profile for the distance for each different discharge along the longitudinal direction of the fiber structure ,
An electrospun fiber structure, wherein the change in distance is provided during electrospinning. Contains at least 50% linear fibers,
The electrospun fiber structure according to claim 8, wherein the at least 50% linear fibers include 50% or more of fibers having a linear portion of 5 µm or more. The electrospun fiber structure according to claim 8 or 9 , comprising at least 50% non-cross-linked fibers with adjacent fibers. The electrospun fiber structure according to any one of claims 8 to 10 , wherein 50% or more of the fibers have an average diameter of 3 to 2000 nm. The fibrous structure includes two or more adjacent layers;
9. Each layer having two adjacent layers has an average diameter that is less than the average diameter of the fibers of one adjacent layer and an average diameter that is greater than the average diameter of the fibers of the adjacent layer. 11. The electrospun fiber structure according to any one of 11 above. Use of the electrospun fiber structure according to any one of claims 8 to 12 ,
Use characterized by being used for tooth bleaching.

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