US2015354096A1PendingUtilityA1

Processing of chemically modified cellulosic fibres

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Assignee: CONVATEC TECHNOLOGIES INCPriority: Dec 20, 2012Filed: Dec 20, 2013Published: Dec 10, 2015
Est. expiryDec 20, 2032(~6.4 yrs left)· nominal 20-yr term from priority
Inventors:Wayne BonnefinLucy BallamySarah WroeDavid ParsonsGarry StoreyJoseph F. Thompson
A61F 2013/00936D04H 1/46A61L 15/28D06M 13/21D04H 1/4258D21H 13/02A61F 13/00063D06M 13/278D01G 15/00B65B 55/02D06M 11/38A61F 2013/0091A61L 15/42D06M 2101/06D01F 2/24D06B 1/00A61F 13/0276A61F 13/01012
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Claims

Abstract

A chemically modified cellulosic fibre or filament having a moisture content of at least 7% by weight obtained by a process comprising the steps of (i) obtaining cellulosic fibres or filament and chemically modifying the cellulose by substitution to increase its absorbency; (ii) washing the fibres after step (i) in a mixture comprising water and up to 99% by weight of water-miscible organic solvent; (iii) drying the fibres to a moisture content of at least 7% by weight, tart abstract here

Claims

exact text as granted — not AI-modified
1 . A chemically modified cellulosic web of needled fibres having a tensile strength of at least 3N per cm measured in the cross direction obtained by processing fibres having a moisture content of at least 7% by weight. 
     
     
         2 . A chemically modified cellulosic fibre having a moisture content of at least 7% by weight. 
     
     
         3 . A chemically modified web of fibres or fibre as claimed in  claim 1  or  claim 2  having a moisture content from 11% to 18% by weight. 
     
     
         4 . A chemically modified web of fibres or fibre as claimed in  claim 1  or  claim 2  having a moisture content from 12% and 15% by weight. 
     
     
         5 . A chemically modified web of fibres or fibre as claimed in  claim 1  or  claim 2  having a moisture content of 15% by weight. 
     
     
         6 . A chemically modified web of fibres or fibre as claimed in any preceding claim wherein the fibres are obtained from a chemical modification process comprising a wash step that uses a wash composition comprising less than 99% by weight of a water-miscible organic solvent. 
     
     
         7 . A chemically modified web of fibres as claimed in  claim 1  or any of  claims 3  to  6  processed by carding and needling having a tensile strength of 3N/cm to 25N/cm. 
     
     
         8 . A chemically modified web of fibres as claimed in  claim 7  having a basis weight of between 80 and 120 gsm. 
     
     
         9 . A chemically modified web or fibres as claimed in  claim 7  or  8  having a tensile strength of from 7N/cm to 25N/cm. 
     
     
         10 . A chemically modified web or fibres as claimed in  claim 7 ,  8  or  9  having a tensile strength of from 10N/cm to 25N/cm 
     
     
         11 . A process for producing a non-woven web of chemically modified cellulosic fibres comprising the steps of:
 (i) obtaining chemically modified cellulosic fibres with a moisture content of at least 7%;   (ii) carding and needling the fibres to make a nonwoven web of fibres.   
     
     
         12 . A process as claimed in  claim 11  wherein the fibres are obtained from a chemical modification process which comprises a step wherein the fibres are washed with a composition comprising less than 99% by weight of an organic solvent. 
     
     
         13 . A process as claimed in  claim 12  wherein the wash composition comprises less than 95% by weight of a water-miscible organic solvent. 
     
     
         14 . A process as claimed in any of  claims 12  to  13  wherein after the washing step, the fibres are dried to a moisture content of at least 7%. 
     
     
         15 . A process as claimed in  claim 12  wherein the fibres are obtained by conditioning the fibres in air having a relative humidity of at least 40% to increase the moisture content of the fibres to least 7%. 
     
     
         16 . A process as claimed in  claim 18  wherein the relative humidity is from 45% to 85%. 
     
     
         17 . A process as claimed in  claim 18  or  19  wherein the relative humidity is from 50% to 65%. 
     
     
         18 . A process as claimed in any of  claims 11  to  17  wherein the fibres have a moisture content of from 11% to 18% by weight. 
     
     
         19 . A process as claimed in any of  claims 11  to  18  wherein the fibres have a moisture content from 12% and 15% by weight. 
     
     
         20 . A process as claimed in any of  claims 11  to  19  wherein the fibres have a moisture content of 14% to 15% by weight. 
     
     
         21 . A process for producing a non-woven web of chemically modified cellulosic fibres comprising the steps of:
 (i) obtaining cellulosic fibres or filament and chemically modifying the cellulose by substitution to increase its absorbency, then;   (ii) washing the fibres with a composition comprising water and up to 99% by weight of water-miscible organic solvent; and then   (iii) drying the fibres in a controlled atmosphere to a moisture content of at least 7% by weight.   
     
     
         22 . A process as claimed in  claim 21  wherein the wash composition comprises less than 95% by weight of an organic solvent. 
     
     
         23 . A process as claimed in  claim 21  or  22  wherein the process comprises the additional step of needling the web to form a wound dressing. 
     
     
         24 . A process as claimed in  claim 23  wherein the process comprises the additional step of sealing and sterilising the dressing in a pouch that maintains the dressing in a sterile and controlled environment. 
     
     
         25 . A process as claimed in any of  claims 21  to  24  wherein the fibres have a moisture content of from 11% to 18% by weight. 
     
     
         26 . A process as claimed in any of  claims 21  to  25  wherein the fibres have a moisture content from 12% and 15% by weight. 
     
     
         27 . A process as claimed in any of  claims 21  to  26  wherein the fibres have a moisture content of 14% to 15% by weight. 
     
     
         28 . A chemically modified cellulosic fibre or filament having a moisture content of at least 7% by weight obtained by a process comprising the steps of
 (i) obtaining cellulosic fibres or filament and chemically modifying the cellulose by substitution to increase its absorbency;   (ii) washing the fibres after step (i) in a mixture comprising water and up to 99% by weight of water-miscible organic solvent;   (iii) drying the fibres to a moisture content of at least 7% by weight.   
     
     
         29 . A process as claimed in  claim 28  wherein the wash composition comprises less than 95% by weight of an organic solvent. 
     
     
         30 . A process as claimed in  claim 28  or  29  wherein the process comprises the additional step of carding and needling the fibre to form a wound dressing. 
     
     
         31 . A process as claimed in  claim 30  wherein the process comprises the additional step of sealing and sterilising the dressing in a pouch that maintains the moisture content of the dressing in a sterile environment. 
     
     
         32 . A process as claimed in any of  claims 28  to  31  wherein the fibres or filaments have a moisture content of from 11% to 18% by weight. 
     
     
         33 . A process as claimed in any of  claims 28  to  32  wherein the fibres or filaments have a moisture content from 12% and 15% by weight. 
     
     
         34 . A process as claimed in any of  claims 28  to  33  wherein the fibres or filaments have a moisture content of 14% to 15% by weight. 
     
     
         35 . A process for producing a non-woven web of chemically modified cellulosic fibres comprising the steps of:
 (i) obtaining cellulosic fibres or filament and chemically modifying the cellulose by substitution to increase its absorbency, then;   (ii) washing the fibres with a composition comprising up to 99% by weight of an organic solvent; and then   (iii) conditioning the fibres in an atmosphere having a relative humidity of at least 40% to increase the moisture content of the fibres to least 7%.   
     
     
         36 . A process as claimed in  claim 35  wherein the wash composition comprises less than 95% by weight of an organic solvent. 
     
     
         37 . A process as claimed in  claim 35  or  36  wherein the conditioning is in air having a relative humidity of 45% to 85%. 
     
     
         38 . A process as claimed in  claim 35  to  37  wherein the relative humidity is from 50% to 65%. 
     
     
         39 . A process as claimed in any of  claims 35  to  38  wherein the fibres have a moisture content of from 11% to 18% by weight. 
     
     
         40 . A process as claimed in any of  claims 35  to  39  wherein the fibres have a moisture content from 12% and 15% by weight. 
     
     
         41 . A process as claimed in any of  claims 35  to  40  wherein the fibres have a moisture content of 14% to 15% by weight. 
     
     
         42 . A process as claimed in  claims 35  to  41  wherein the process comprises the additional step of carding and needling the fibres to form a wound dressing. 
     
     
         43 . A process as claimed in  claim 42  wherein the process comprises the additional step of sealing and sterilising the dressing in a pouch that maintains the moisture content of the dressing in a sterile environment.

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