Classifications

• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01D—MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
  • D01D5/00—Formation of filaments, threads, or the like
  • D01D5/0007—Electro-spinning
  • D01D5/0061—Electro-spinning characterised by the electro-spinning apparatus
  • D01D5/0076—Electro-spinning characterised by the electro-spinning apparatus characterised by the collecting device, e.g. drum, wheel, endless belt, plate or grid
  • D01D5/0084—Coating by electro-spinning, i.e. the electro-spun fibres are not removed from the collecting device but remain integral with it, e.g. coating of prostheses
• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
  • D01F11/00—Chemical after-treatment of artificial filaments or the like during manufacture
  • D01F11/04—Chemical after-treatment of artificial filaments or the like during manufacture of synthetic polymers

Definitions

• the invention relates to a method for deposition of functional layer of polymeric nanofibres on a surface of a substrate, by which on the surface of the substrate an auxiliary layer of polymeric material in the form of nanofibres and/or nanoparticles and/or microfibres and/or microparticles is deposited electrostatically.
• US 2005/0192622 further discloses several other methods how to increase adhesion of layer of polymeric nanofibres to the substrate.
• One of them consists in that on the substrate a primary layer of polymeric material in the form of droplets is first deposited through electrostatic spraying , on which subsequently the covering layer of polymeric nanofibres is ⁇ deposited through electrostatic spinning The primary layer is before deposition of the covering layer, during it or after it dissolved in a suitable manner, for example by dipping into the solvent or by exposition to an increased temperature, while it binds the covering layer of nanofibres to the substrate after drying.
• the goal of the invention is to propose a method for deposition of a layer of polymeric nanofibres on a surface of an arbitrary substrate, which would remove or at least reduce disadvantages of the prior art, secure a sufficient adhesion of layer of nanofibres to the substrate and which would be applicable even in case of electrostatic spinning of polymer melts.
• Goals of the invention have been achieved by a method for deposition of functional layer of polymeric nanofibres on a surface of a substrate at which on the surface of the substrate an auxiliary layer of polymeric material in the form of nanofibres and/or nanoparticles and/or microfibres and/or microparticles is deposited electrostatically, ' , ⁇ .
• auxiliary layer of polymeric material in the form of nanofibres and/or nanoparticles and/or microfibres and/or microparticles is deposited electrostatically, ' , ⁇ .
• the nanofibres and/or nanoparticles a ⁇ d/or microfibres and/or microparticies of the auxiliary layer of polymeric material are during deposition and/or after deposition on the substrate dissolved on their, surfaces, thanks to which they adhere well to the substrate.
• the functional layer of polymeric nanofibres is, deposited, which adheres well to the auxiliary layer of polymeric material. Through r .this a high adhesion of the functional layer of nanofibres in principle to a ⁇ y . surface and material is secured.
• auxiliary layer For small material in the auxiliary layer it is convenient to use for surface dissolution of nanofibres and/or nanoparticles and/or microfibres and/or; " , microparticles of the auxiliary layer of polymeric material vapours of the solyent. At its greater quantity, aerosol of the solvent may be used. ⁇ , .'; ;
• polymeric nanofibres of the functional layer After deposition of polymeric nanofibres of the functional layer on surface dissolved nanofibres and/or nanoparticles and/or microfibres and/or microparticles of the auxiliary layer of polymeric material there may also occur their surface dissolution, by which even greater strength of binding of the functional layer, the auxiliary layer and the substrate is ensured.
• Polymeric nanofibres of the functional layer are at the same time on their surface dissolved due to residues of the solvent in nanofibres and/or nanoparticles and/or microfibres and/or . ⁇ m jcroparticles of the auxiliary layer of polymeric material or their increased temperature.
• the substrate textile When performing the, method according to the invention, in the first electrostatic spinning field on, the substrate textile there is evenly deposited an auxiliary layer of polymeric material in a form of a layer of polymeric nanofibres, whose surface density varies, in dependence on the type of polymeric matrix, content of a solvent in it, speed of motion of the substrate textile and requirements on the resultant product, from 0,05 up to 1 g/m 2 , usually in the range from 0,1 to 0,7 g/m 2 , nevertheless in specific examples of embodiment the surface density of the auxiliary layer may be increased even above 1 g/m 2 .
• Electrostatic spinning upon usage of rotating cylindric spinning electrode simultaneously secures uniform distribution of polymeric material of the auxiliary layer on the substrate textile.
• the purpose of the auxiliary layer is to increase the adhesion between the substrate textile and the functional layer of nanofibres.
• the nanofibres of the auxiliary layer of polymeric material are depending on the type of polymeric matrix and its quantity in the auxiliary layer dissolved on their surfaces by action of vapours of a solvent, aerosol of the solvent, increased temperature or by combination of any of these factors.
• the quantity of dissolved material of the ⁇ auxiliary layer of polymeric material can be easily controlled.
• the nanofibres of the auxiliary layer of polymeric material preserve their original shape and the even distribution on the substrate textile, nevertheless they adhere to -it more closely, while a part of polymeric material of the auxiliary layer may at the* same time may penetrate into the inner structure of the substrate textile.
• a high adhesion of the auxiliary layer of polymeric material to the substrate textile is secured, without expressive influence on; characteristics of composite created in such a way, because relatively small quantity of polymeric material in the auxiliary layer and only surface dissolution of nanofibres ensures, that a continuous film impervious to air is not created on the surface of the substrate textile, and that the substrate textile keeps even after deposition and surface dissolution of nanofibres of auxiliary layer of polymeric material in principle its parameters, especially as regards to its air permeability and pressure drop.
• a stream of 'air or other suitable gas may be used.
• this can also promote the surface dissolution of polymeric nanofibres of the auxiliary layer, as it can be pre-heated to the required temperature and/or it may serve to carry and/or to deflect the vapours and/or aerosol of the solvent.
• the means for bringing the vapours and/or aerosol of the solvent to the auxiliary layer of polymeric material formed of nanofibres and/or means for increasing its temperature are preferably installed in vicinity of exit of the substrate textile from the first electrostatic spinning field and/or entrance of the substrate textile into the, second electrostatic spinning field and/or between them, possibly for portions of the path of the substrate textile.
• each of them is controllable independently on others, so that in each moment there is achieved just the required quantity of vapours and/or aerosol and/or thermal energy brought to the substrate textile and to the auxiliary layer of polymeric material.
• the vapours and/or aerosol of solvent when used, they may be applied to the substrate textile still before depositing the auxiliary layer of polymeric .material and so the nanofibres of auxiliary layer do not become dry after deposition on the substrate textile or dissolve on their surfaces immediately after their deposition.
• the nanofibres of the auxiliary layer may be dissolved on their surfaces by action of vapours and/or aerosol of the solvent and/or increased temperature stilh-b ' efore their deposition on the substrate textile, during their deposition.
• This* is especially advantageous in cases, when the used polymeric material of ⁇ the auxiliary layer becomes due to its chemical properties and/or conditions in electrostatic spinning field diyquickly, and so on the substrate textile already would be deposited totally or nearly totally solidified nanofibres.
• the substrate textile with the auxiliary layer is brought into the second electrostatic field, where on these nanofibres a functional layer of polymeric nanofibres with parameters, which are given by the considered utilisation of the final product, is deposited.
• a functional layer of polymeric nanofibres with parameters which are given by the considered utilisation of the final product.
• solvent in the auxiliary layer of polymeric material and/or its increased temperature further causes partial dissolution of polymeric nanofibres of the functional layer on their surface, due to which the functional layer adheres well to the auxiliary layer of polymeric material and to the substrate textile, so that after evaporation of the solvent and/or reduction of the temperature, sufficiently high adhesion is achieved between the substrate textile, the auxiliary layer of polymeric material and the functional layer.
• the substrate textile with surface dissolved , nanofibres of the auxiliary layer of polymeric material is brought into the second electrostatic field after the temperature of the substrate textile with the ( auxiliary layer is reduced and/or concentration of rests of solvent in it is reduced, through which the dissolution of polymeric nanofibres of the functional layer is completely removed or reduced in a required rate.
• auxiliary layer in the form of polymeric nanofibres through electrostatic spinning ensures its uniformity all over the whole surface of the substrate textile, thus , ' also uniform adhesion of the functional layer of nanofibres to it.
• This solution is simultaneously structurally as well as operationally the simplest one, as it does not requires installation and operation of elements other than of tw ⁇ identical spinning electrodes in combination with which, only one collecting' electrode may be utilised.
• the quantity of polymeric material in the auxiliary layer is so small, that in principle it does not play any role in what formations it is to be found. Therefore for creation and deposition ⁇ of the auxiliary layer of polymeric material even other methods of electrostatic spinning than those utilising some of the above mentioned spinning electrodes, or generally even other principles than the electrostatic spinning, may be used. So the auxiliary layer of polymeric material may be created, next' to electrostatic spinning, e.g.
• the functional layer of nanofibres may be created also through any ⁇ technique of electrostatic spinning, e.g. through spinning from the nozzle (nozzles) nevertheless the 'electrostatic spinning upon usage of elongated cylindric electrode described e.g. in CZ patent 294274 seems to be the most useful at present.
• the functional layer of nanofibres may be created of polymeric nanofibres of any electrostatically spinnable polymer in the form of solution or polymer melt, possibly the ,, nanofibres of the functional layer may contain various active substances,;, like e.g. particles of photodynamic sensitizers according to CZ PV 2006-432, particles of low-molecular substance, or metal nanoparticles according to CZ PV 2005-225, etc., which spreads possibilities of their utilisation even on further applications outside filtration.
• the layer of functional nanofibres in principle on any substrate, not only on the textile described in example, of embodiment.
• the auxiliary layer of nanofibres and their surface dissolution possibly in combination with surface dissolution of nanofibres of the functional layer, secures a sufficient adhesion of the functional layer in principle to any surface and material.
• the functional layer of nanofibres may be therefore deposited not only on planar units such as filtration paper or filtration textile, but also, on .surfaces in principle of any products from any material, both finished or designed for further processing.
• the described procedure eliminates disadvantages of the background art in such a manner that it enables any combination of polymeric material of auxiliary layer with material of the functional layer of nanofibres, simultaneously secures a high adhesion .of .the auxiliary layer to the substrate immediately after depositing the auxiliary layer or during it.
• the auxiliary layer as well as the functional layer of nanofibres jat the same time may be prepared both from the same polymeric material, orjjom various polymeric materials, without necessity to seek for suitable combinations of their properties, especially their resistance towards the given solvent or melting point. This of course not only substantially spreads the portfolio of applicable polymeric materials almost without limitation, but also significantly reduces financial as well as technological demands of the whole process.

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Citations (8)

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• 2009
  • 2009-03-09 CZ CZ20090149A patent/CZ2009149A3/cs unknown
• 2010
  • 2010-03-03 WO PCT/CZ2010/000027 patent/WO2010102593A2/en active Application Filing

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