Non-woven fabrics and method for producing them

Abstract

The invention relates to non-woven fabrics comprising threads not produced with the spun-bonding method, for example made of non-melt spinnable thread-forming materials. The use of these fibers, optionally in combination with filaments produced using the spun-bonding method, allows the production of novel non-woven fabrics with novel property combinations. The production can be carried on conventional spun-bonding equipment, wherein part of the extruding devices are used as conveyors for the threads not produced with the spun-bonding method.

1 . A non-woven fabric with a basis weight of up to 250 g/m 2  and a high level of uniformity, expressed by a mass coefficient of variance of the basis weight distribution CV of less than 10%, as determined by samples measuring 5*5 cm 2 , comprising randomly deposited threads not produced with the spun-bonding method.  
   
   
       2 . A non-woven fabric comprising randomly deposited threads made of non-melt spinnable materials.  
   
   
       3 . A non-woven fabric according to  claim 1 , characterized in that it comprises threads made of fibers or filaments.  
   
   
       4 . A non-woven fabric according to  claim 1 , characterized in that it has a level of uniformity, expressed by a mass coefficient of variation of the basis weight distribution CV of less than 7%.  
   
   
       5 . A non-woven fabric according to  claim 1 , characterized in that it comprises threads made of high-strength polymer fibers or high-strength polymer filaments.  
   
   
       6 . A non-woven fabric according to  claim 1 , characterized in that it comprises threads made of metal or metal alloys.  
   
   
       7 . A non-woven fabric according to  claim 1 , characterized in that it comprises threads made of polymers with additives, preferably spin-dyed and/or flame-protected polymers.  
   
   
       8 . A non-woven fabric according to  claim 1 , characterized in that it additionally comprises randomly deposited filaments produced with the spun-bonding method.  
   
   
       9 . A non-woven fabric according to  claim 8 , characterized in that the filaments produced with the spun-bonding method are separable filaments derived from multi-component filaments, comprising at least two separable, melt-spinnable and thread-forming polymers that are not mutually compatible, preferably separable filaments from the combinations polyester/polyamide, polyester/polyolefin, polyamide/polyolefin, polyolefin/polyolefin, polyester/ polyurethane, polyamide/polyurethane, polyolefin/polyurethane.  
   
   
       10 . A non-woven fabric according to  claim 2 , characterized in that it is made exclusively of filaments and/or staple yarns of non-melt spinnable thread-forming materials.  
   
   
       11 . A non-woven fabric according to  claim 2 , characterized in that the non-melt spinnable material is selected from the group comprising cotton, wool, cellulose and cellulose derivatives, particularly rayon, modal, copper rayon, cellulose acetate, semi-acetate or triacetate, polyacryl nitrile, aromatic polyamides (aramides), non-thermoplastic polyurethanes, non-melt spinnable halogenated polyolefins, such as polytetrafluoroethylene, polyvinylchloride or polyvinylidene chloride, as well as rubbers, polyvinyl alcohol or carbon.  
   
   
       12 . A non-woven fabric according to  claim 2 , characterized in that the non-melt spinnable material is a thread-forming polymer or a polymer that can be spun with a peeling process.  
   
   
       13 . A non-woven fabric according to  claim 8 , characterized in that the filaments produced with the spun-bonding method are derived from melt-spinnable thermoplastic polycondensates, selected from the group comprising polyesters, polyamides, polyether ketones, polyarylene sulfides, polyarylene ether sulfones, polycarbonate, proteins and protein derivatives, or which are derived from melt-spinnable thermoplastic polymerides selected from the group comprising polyolefines and polyurethanes, or which are derived from other melt-spinnable polyurethanes selected from the group comprising metals and glass or from a combination of two or more of these polycondensates, polymerides or other materials.  
   
   
       14 . A non-woven fabric according to  claim 1 , characterized in that it has been bonded by using mechanical, hydromechanical and/or thermal methods, particularly by using embroidering looms or water jets.  
   
   
       15 . A method for producing non-woven fabrics comprising the following measures: 
 i) feeding threads to several supply devices A, particularly threads comprising fibers or filaments made of non-melt spinnable materials,    ii) optionally feeding threads to further supply devices B, which threads differ from the threads located in the supply devices A,    iii) pulling the threads off the supply devices A by means of at least one conveying device,    iv) random depositing of the threads pulled off in step iii) in the form of a non-bonded non-woven onto a transport device in multiple layers,    v) optionally pulling the threads off the supply devices B by means of at least one conveying device,    vi) optionally random depositing of the threads pulled off in step v) in the form of a non-bonded non-woven onto a transport device in multiple layers, and    vii) bonding the obtained non-bonded non-woven by using familiar mechanical, hydromechanical, pneumatic and/or thermal methods and/or by using chemical binding agents.    
   
   
       16 . A method for producing non-woven fabrics comprising the following measures: 
 i) feeding threads comprising fibers or filaments made of non-melt spinnable materials originating from a production system A′ used for these threads and pulling these threads off with at least one conveying device,    ii) optionally feeding threads to several supply devices A, particularly threads comprising fibers or filaments made of non-melt spinnable materials,    iii) optionally feeding threads to further supply devices B, which threads differ from the threads located in the supply devices A,    iv) optionally pulling the threads off the supply devices A by means of at least one conveying device,    v) random depositing of the threads pulled off in step i) in the form of a non-bonded non-woven onto a transport device in multiple layers,    vi) random depositing of the threads pulled off in step iv) in the form of a non-bonded non-woven onto a transport device in multiple layers,    vii) optionally pulling the threads off the supply devices B by means of at least one conveying device,    viii) optionally random depositing of the threads pulled off in step vii) in the form of a non-bonded non-woven onto a transport device in multiple layers, and    ix) bonding the obtained non-bonded non-woven by using familiar mechanical, hydromechanical, pneumatic and/or thermal methods and/or by using chemical binding agents.    
   
   
       17 . A method according to  claim 15 , characterized in that reels or cans are used as the supply devices.  
   
   
       18 . A method according to  claim 16 , characterized in that wet or dry spinning systems or systems for secondary spinning are used as the different production systems A′.  
   
   
       19 . A method according to  claim 15 , characterized in that pneumatic conveying devices are used as the conveying devices.  
   
   
       20 . A method according to  claim 15 , characterized in that the threads are guided by thread guides from the supply devices A and/or B and/or from the different production system A′ prior to entering the conveying devices, which guides are provided on the inlet openings of the conveying devices.  
   
   
       21 . A method according to  claim 15 , characterized in that the method is carried out on spun-bonding equipment, in which the spinning and extruding units are disposed along the entire product width.  
   
   
       22 . A method according to  claim 15 , characterized in that the method is carried out on spun-bonding equipment on which individual round spinpacks are provided as spinning and extruding units to produce finished extruded filaments and which comprises a transport system, which is used to feed the filaments to a belt, the product width being adjustable via the transport system.  
   
   
       23 . A method according to  claim 15 , characterized in that the threads A and/or threads A′ and optionally the threads B are deposited randomly and not towards a previously defined location and are distributed in several layers on top of each other on an advancing belt.  
   
   
       24 . A method according to  claim 15 , characterized in that in addition to the threads A and/or threads A′ and optionally the threads B filaments C are deposited, which have been produced in the same system by melt-spinning thread-forming materials and that following passage through an extruding device they are deposited together with the threads A and/or threads A′ and optionally the threads B on the transport device.  
   
   
       25 . A method according to  claim 24 , characterized in that the filaments C are multi-component filaments, which are made of at least two separable, melt-spinnable and thread-forming polymers that are not compatible with each other, which are separated by means of water jet treatment.  
   
   
       26 . A method according to  claim 15 , characterized in that the random deposition of the threads is achieved by the random movement of the depositing units, by the random movement of the belt, the random movement of the air between the depositing unit and the belt, or by a combination of two or three of these measures.  
   
   
       27 . A method according to  claim 15 , characterized in that the threads deposited on the transport device are retained there by a vacuum.  
   
   
       28 . A method according to  claim 15 , characterized in that the bonding is carried out by means of water jets.  
   
   
       29 . The use of the non-woven fabrics according to  claim 1  as textiles, as clothing materials, as home textiles or as industrial textiles, as technical tissues or as carriers for coated or impregnated non-wovens, or they are used in the filtration of fluid flows or fluids.  
   
   
       30 . The use of a non-woven fabric according to  claim 1  in a fuel cell.