Degumming of bast fibres

Abstract

A method for separating decorticated bast skin into individual fibres, comprising maintaining decorticated bast skin in a closed container in the presence of at least one enzymatic and/or chemical retting agent for a period sufficient for at least a portion of the fibre bundles to separate into individual fibres.

1 . A method for separating decorticated bast skin into individual fibres, comprising maintaining decorticated bast skin in a closed container in the presence of at least one enzymatic and/or chemical retting agent for a period sufficient for at least a portion of the skin to separate into individual fibres.  
     
     
         2 . A method according to  claim 1 , wherein the bast skin is decorticated bast skin comprising fibre bundles.  
     
     
         3 . A method according to  claim 1  or  claim 2 , wherein the bast skin comprises at least in part fresh green bast skin and the at least one enzymatic retting agent is a naturally occurring enzyme of the green bast skin.  
     
     
         4 . A method according to any one of the previous claims  claim 1 , wherein the bast skin is maintained under anaerobic conditions for a period sufficient for at least a portion of the bast skin to separate into individual fibres.  
     
     
         5 . A method according to  claim 4 , wherein the anaerobic conditions are established at least in part by the production of gas(es) by the fresh green skin.  
     
     
         6 . A method according to any one of  claim 3  to  5   claim 3 , wherein the naturally occurring enzyme is augmented by at least one other enzymatic or chemical retting agent or a combination thereof.  
     
     
         7 . A method according to  claim 1  or  claim 2 , wherein the bast skin is substantially dry bast skin.  
     
     
         8 . A method according to  claim 7 , wherein the bast skin is contacted with at least one enzymatic and/or chemical retting agent(s).  
     
     
         9 . A method according to any one of the preoeding claims  claim 1 , wherein the bast skin is contacted with the enzyme and/or chemical retting agent by soaking the skin in a solution of the agent(s) and draining the skin before placing it in the container.  
     
     
         10 . A method according to any one of the preceding claims  claim 1 , wherein the enzymatic or chemical retting agent(s) is/are selected from the group consisting of Crystalzyme. Flaxzym, Caustic, Soda ash and Sodium Silicate, Oxalic Acid, and EDTA.  
     
     
         11 . A method according to any one of the preceding claims  claim 1 , wherein the concentration of the enzyme solution contacted with the bast skin is in the range of about 0.1 to about 2% (w/v).  
     
     
         12 . A according to any one of the preceding claims  claim 1 , wherein the separation is carried out at a temperature in range of about 25° C. to about 55° C.  
     
     
         13 . A method according to any one of the precedind claims  claim 1 , wherein the bast skin is derived from a bast plant selected from the group consisting of ramie, flax and hemp.  
     
     
         14 . A method according to any one of the preceding claims  claim 1 , wherein the bast skin is derived from hemp.  
     
     
         15 . A method according to any one of the preceding claims  claim 1 , wherein the closed container is a substantially gas impervious container.  
     
     
         16 . A method according to  claim 15 , wherein the substantially gas impervious container is in the form of a bag or the like into which decorticated skins may be placed.  
     
     
         17 . A method according to  claim 16 , wherein the bag is formed at least in part from a natural or synthetic plastic.  
     
     
         18 . A method according to  claim 17 , wherein the plastic is a flexible plastic.  
     
     
         19 . A method according to any one of the  1  to  17   claim 1 , wherein the container is formed from a gas-pervious material which has been treated to make it substantially gas impervious.  
     
     
         20 . A method according to any one of the previous claims  claim 1  when carried out under controlled temperature conditions.  
     
     
         21 . A method according to any one of  claim 1  to  18   claim 1 , carried out under uncontrolled temperature conditions.  
     
     
         22 . A method according to any one of  claim 21 , wherein the contained bast skins are left in the open for a predetermined period.  
     
     
         23 . A method according to any one of the preceding claims claim 1 , further comprising contacting the bast skins with hot water.  
     
     
         24 . A method according to  claim 23 , wherein the hot water treated fibres are contacted at least one time with either hot or cold water.  
     
     
         25 . A method according to  claim 23  or  24 , wherein the fibres are subjected to a squeezing to remove a least part of liquid therefrom.  
     
     
         26 . A method according to any one of claim  1 to  23   claim 1 , further including the step of contacting the treated fibre with aqueous media and compressing the fibre.  
     
     
         27 . A method according to  claim 25 , wherein the treated fibres are subjected to a least 2 aqueous media contacting steps.  
     
     
         28 . A method according to claims  26  or  claim 27 , wherein the aqueous media is water.  
     
     
         29 . A method according to any one of  claims 26  to  28   claim 26 , wherein the compressing step involves combined rolling and compressing of the fibres.  
     
     
         30 . A method according to  claim 29 , wherein the compressing step involves pressure roller compression (squeezing) of the fibres.  
     
     
         31 . A method according to any one of  claims 26  to  30   claim 26  wherein the fibre is contacted with the aqueous media at elevated temperature.  
     
     
         32 . A method according to  claim 31 , wherein the elevated temperature is in the range of about 70 to 90° C.  
     
     
         33 . A method according to  claim 31  or  claim 32 , wherein the fibre is contacted with the aqueous media by dunking the fibre in the aqueous media.  
     
     
         34 . A fibre produced by a method according to any one of the preceding claims  claim 1 .  
     
     
         35 . A fibre according to  claim 34 , which has been subjected to an opening operation.  
     
     
         36 . A fibre according to any one of  claims 34  to  35   claim 34  which has been subjected to a carding operation.  
     
     
         37 . Yarn comprising a fibre according to any one of  claims 34  to  36   claim 34 .  
     
     
         38 . A fabric or material comprising a fibre in accordance with any one of  claims 34  to  37   claim 34 .  
     
     
         39 . A method for separating bast skin into individual fibres, comprising maintaining bast skin under anaerobic conditions in the presence of at least one enzymatic and/or chemical retting agent for a period sufficient for at least a portion of the skin to separate into individual fibres.  
     
     
         40 . A method for determining the degree of degumming of a retted bast fibre product, comprising determining fibre width of the retted bast fibre using an optical fibre diameter measuring means.