Fibrillation of natural fibres

Abstract

Fibrillation of certain cellulosic fibres has been widely studied, and fibrillation can be utilised to improve fabric performance, for example strength, absorbency, surface area together with handle and opacity. However, it believed that keratinous fibres such as wool have not been treated in this way. The invention seeks to provide a fibrillated keratinous fibre fabric and a method of fibrillating natural fibres. A textile fabric of keratinous fibre is disclosed characterised by the presence of fibrils, micro-fibrils and proto-fibrils. The fibrils may be further characterised as having diameters in the range 3 μm to 5 μm and by having lengths in the range 25 μm to 60 μm. Preferably, the fabric is a woven, knitted, non-woven or composite fabric. A method of treating natural fibres is also disclosed which comprises:- a pre-treatment to remove surface lipid materials or scales, e.g. using an oxidising agent; a treatment to remove or partially remove intercellular cement, e.g. using an enzyme; and the application of mechanical agitation under aqueous conditions, e.g. hydroentanglement, to complete fibrillation.

1 . A textile fabric of keratinous fibres characterised by the presence of fibrils, micro-fibrils and proto-fibrils.  
     
     
         2 . A fabric as claimed in  claim 1  wherein the fibrils are further characterised as having diameters in the range 3 μm to 5 μm and by having lengths in the range 25 μm to 60 μm.  
     
     
         3 . A fabric as claimed in either of claims  1  or  2  wherein the fabric is a woven, knitted, non-woven or composite fabric.  
     
     
         4 . A method of treating natural fibres which comprises: 
 a pre-treatment to remove surface lipid materials or scales;    a treatment to remove or partially remove intercellular cement; and    the application of mechanical agitation to complete fibrillation.    
     
     
         5 . A method as claimed in  claim 4  wherein the first step is carried out with an oxidising agent.  
     
     
         6 . A method as claimed in  claim 5  wherein the oxidising agent is permonosulphuric acid or its salt (PMS), dichloroisocyanuric Acid or its salt (DCCA), or sodium hypochlorite.  
     
     
         7 . A method as claimed in  claim 4  or  5  wherein the first step is carried out using electrical discharge (plasma) treatments.  
     
     
         8 . A method as claimed in any of  claims 4  to  7  wherein he second stage of the process, namely removal of intercellular cement, is carried out using an enzyme treatment.  
     
     
         9 . A method as claimed in  claim 8  wherein the enzyme is Papain.  
     
     
         10 . A method as claimed in any of  claims 4  to  9  wherein the mechanical agitation is preferably carried out under aqueous conditions.  
     
     
         11 . A method as claimed in any of  claims 4  to  10  wherein energy is introduced by the process known as “hydroentanglement” in which water jets are used to agitate the fibres and partially break them down into smaller, finer fibres, fibrils or micro fibrils.  
     
     
         12 . A method as claimed in any of  claims 4  to  11  wherein energy is introduced may means including laser etching, ultrasonic, plasma, mechanical raising or emerising, separately or in combination.  
     
     
         13 . A method as claimed in any of  claims 4  to  12  wherein the fibres are keratinous fibres.  
     
     
         14 . A method as claimed in  claim 13  wherein the fibres are selected from cashmere, camel, alpaca, mohair, and especially wool.  
     
     
         15 . A method as claimed in any of  claims 4  to  14  wherein the fibres are initially scoured using a detergent or surfactant.  
     
     
         16 . A method as claimed in any of  claims 4  to  15  wherein the chemical treatments of the first and second steps are applied using the “exhaustion” technique from long liquors.  
     
     
         17 . A method as claimed in any of  claims 4  to  16  wherein a reducing agent is used following step two.  
     
     
         18 . A method as claimed in  claim 17  wherein the reducing agents is sodium sulphite or sodium bisulphite.