Plant for producing a fibre web of plastic and cellulose fibres

Abstract

A plant serves as a mean for production of a fibre web of synthetic fibres, such as plastic fibres and absorbent fibres, such as viscose and cellulose fibres. The plant includes a forming head preliminary to lay a homogeneously and smoothly distributed fibre layer on a net shaped wire. Furthermore the plant includes a hydro-entangling section with liquid nozzles with powerful liquid jets to treat the in the forming head formed fibre layer, which consists of both synthetic—and absorbent fibres. The plant also includes an oven subsequently to thermal bond the synthetic fibres with cross bonds in the affected areas. Finally the dried web is winded up in a roller. By the help of the plant according to the invention, by higher production speed than known previously a fibre web can be produced, which is far cheaper, and which has a better and more homogeneous structure than similar conventional fibre webs.

1. A plant for producing a nonwoven fabric at least of synthetic fibres comprising:
 at least one air-laying station comprising:
 an endless wire, 
 a suction box, which is connected to a vacuum pump, said suction box being placed under said endless wire, 
 a house with one or more fibre inlets, said house being placed above the upper part of said endless wire, 
 a number of rotatably arranged wings for during operation distributing the fibres in a non-woven web upon the upper part of said endless wire, said wings being placed above said endless wire in said house, 
 at least one heat-treatment station for bonding the synthetic fibres by heating the web, said heat-treatment station being arranged downstream of said at least one air-laying station, 
 at least one hydro-entangling station for directing a number of powerful liquid jets against the bonded web, said hydro-entangling station being arranged downstream of said at least one heat-treatment station, and 
 means for continuous transport of the web through the plant. 
 
 
     
     
       2. A plant according to  claim 1  wherein at least one drying station for drying the hydro-entangled nonwoven web is arranged downstream of the hydro-entangling station. 
     
     
       3. A plant according to  claim 2  wherein the drying station is adapted to act upon the hydro-entangled nonwoven web with temperature sufficient to further bond the synthetic fibres. 
     
     
       4. A plant according to  claim 2  wherein the drying station comprises a rotatable drum which has a perforated wall for during operation supporting a length of the hydroentangled nonwoven web and simultaneously allowing a stream of air to pass. 
     
     
       5. A plant according to  claim 1  wherein the plant comprises at least three in succession arranged airlaying stations. 
     
     
       6. A nonwoven fabric in the form of a three-layered hydro-entangled sandwich fibre web comprising at least synthetic fibres and cellulosic fibres produced in a plant comprising:
 at least one air-laying station comprising: 
 an endless wire, 
 a suction box, which is connected to a vacuum pump, said suction box being placed under said endless wire, 
 first, second, and third air-laying forming heads each comprising a house with one or more fibre inlets, said house being placed above the upper part of said endless wire,and a number of rotatably arranged wings for during operation disbributing the fibres in a non-woven web upon the upper part of said endless wire, said wings being placed above said endless wire in said house, 
 at least one beat-treatment station for bonding the synthetic fibres by heating the web, said heat-treatment station being arranged downstream of said at least one air-laying station, 
 at least one hydro-entangling station for directing a number of powerful liquid jets against the bonded web, said hydro-entangling station being arranged downstream of said at least one heat-treatment station, and 
 means for continuous transport of the web through the plant,  
 wherein the non-woven fabric is produced by:
 supplying synthetic fibres to the first forming head for forming a layer of the web;   supplying cellulose fibres to the second forming head for forming another layer of the web;   supplying synthetic fibres to the third forming head for forming another layer of the web;   successively laying the layers on top of one another whereby a three-layered sandwich fibre web is formed;   hydro-entangling the thus formed web for forming a strong bond between the fibres in the layers of the web; and   heating the web at the heat-treatment station for bonding the synthetic fibres and drying the web.   
 
     
     
       7. A nonwoven fabric according to  claim 6  wherein at least part of the synthetic fibres are bi-component fibres, which each consists of a core of a first plastic surrounded by a second plastic having a higher lower melting point than the first plastic. 
     
     
       8. A nonwoven fabric according to  claim 6  wherein the fabric comprises cellulose fibres present in an amount of between 50% and 95%, wherein the cellulose fibres are provided in the web by forming a separate layer of the cellulose fibres and associating the layer of cellulose fibres with the layer of synthetic fibres prior to hydro-entangling and heating of the web. 
     
     
       9. A nonwoven fabric according to claim  6  8 wherein the fabric comprises cellulose fibres present in an amount of between 60% and 90%. 
     
     
       10. A nonwoven fabric according to claim  6  8 wherein the fabric comprises cellulose fibres present in an amount of between 75% and 85%. 
     
     
       11. A nonwoven fabric according to claim 6 wherein the three-layered hydro-entangled sandwich fibre web comprises top, bottom and middle layers, with the top and bottom layers comprising the synthetic fibres and the middle layer comprising the cellulose fibres. 
     
     
       12. A plant according to claim 1, wherein the plant is used for production of a three-layered sandwich-fibre web. 
     
     
       13. A process for forming a three-layered hydro-entangled sandwich fibre web, said process comprising:
 supplying to a first air-laying forming head fibres for the bottom layer, said fibres comprising at least synthetic fibres;   supplying to a second air-laying forming head fibres for the middle layer, said fibres comprising at least cellulose fibres;   supplying to a third air-laying forming head fibres for the top layer, said fibres comprising at least synthetic fibres;   forming the three layers in the each layer's separate forming head;   successively laying the layers on top of one another whereby a three-layered sandwich fibre web is formed;   hydro-entangling the thus formed web for forming a strong bond between the fibres in the web; and   heating the web for bonding the synthetic fibres and drying the web.   
     
     
       14. A nonwoven fabric comprising the three-layered hydro-entangled sandwich fibre web produced by the process of claim 13. 
     
     
       15. A nonwoven fabric according to claim 14 wherein the web comprises at least synthetic fibres and cellulosic fibres wherein at least part of the synthetic fibres are bi-component fibres, which each consists of a core of a first plastic surrounded by a second plastic having a lower melting point than the first plastic. 
     
     
       16. A nonwoven fabric according to claim 15 wherein the fabric comprises cellulose fibres present in an amount of between 50% and 95%, wherein the cellulose fibres are provided in the web by forming a separate layer of the cellulose fibres and associating the layer of cellulose fibres with the layer of synthetic fibres prior to hydro-entangling and heating of the web.