Compositions comprising microfibrilated cellulose and polymers and methods of manufacturing fibres and nonwoven materials therefrom

Abstract

Fibres and nonwoven materials comprising microfibrillated cellulose, and optionally inorganic particulate material and/or additional additives, and optionally a water soluble or dispersible polymer. Nonwoven materials made from fibres comprising microfibrillated cellulose, and optionally inorganic particulate material and/or a water soluble or dispersible polymer.

1 .- 78 . (canceled) 
     
     
         79 . A method for preparing an aqueous suspension comprising microfibrillated cellulose with enhanced viscosity and tensile strength properties, the method comprising a step of microfibrillating a fibrous substrate comprising cellulose in an aqueous environment to produce an aqueous suspension comprising microfibrillated cellulose, and further comprising subjecting the aqueous suspension comprising microfibrillated cellulose to sonication to produce the aqueous suspension comprising microfibrillated cellulose with enhanced viscosity and tensile strength properties. 
     
     
         80 . The method according to  claim 79 , wherein the ultrasonic energy is applied at an energy compensation rate of up to 1000 kwh per tonne of dried fibrils, 2500 kwh per tonne of dried fibrils, up to 5000 kwh per tonne of dried fibrils and up to 10000 kwh per tonne of dried fibrils. 
     
     
         81 . The method according to any one of the preceding claims, wherein the aqueous suspension comprising microfibrillated cellulose is subject to sonication for at least 30 seconds, at least 1 minute, at least 2 minutes, at least 5 minutes, at least 10 minutes and at least 20 minutes or longer. 
     
     
         82 . The method according to any one of the preceding claims, wherein said sonication is conducted with one or more devices selected from a group consisting of an ultrasonic probe, an ultrasonic water bath, an ultrasonic homogenizer, an ultrasonic foil and an ultrasonic horn. 
     
     
         83 . The method according to any one of the preceding claims, wherein said sonication is run in continuous mode. 
     
     
         84 . The method according to any one of the preceding  claims 79 - 82 , wherein said sonication is run in pulse mode. 
     
     
         85 . The method according to any one of the preceding claims, wherein the sonication is performed at an amplitude of up to 60%, up to 80%, up to 100% and up to 200% or more. 
     
     
         86 . The method according to any one of the preceding claims, wherein the fibrous substrate comprising cellulose is in the form of a pulp, for example, a chemical pulp, or a chemithermomechanical pulp, or a mechanical pulp, or a recycled pulp, or a paper broke pulp, or a papermill waste stream, or waste from a papermill, or combinations thereof. 
     
     
         87 . The method according to any one of the preceding claims, wherein the grinding vessel is selected from the group consisting of a tower mill and a stirred media detritor. 
     
     
         88 . The method according to any one of the preceding claims, wherein said method further comprises one or more of high shear mixing, homogenization and refining either before or after the sonication step. 
     
     
         89 . The method according to any one of the preceding claims, wherein the microfibrillating step comprises microfibrillating the fibrous substrate comprising cellulose in 10 the aqueous environment in the presence of an inorganic particulate material to produce an aqueous suspension comprising microfibrillated cellulose and inorganic particulate material. 
     
     
         90 . The method according to  claim 89 , wherein the microfibrillating step comprises grinding the fibrous substrate comprising cellulose in the presence of the inorganic particulate material in a grinding vessel. 
     
     
         91 . The method according to any one of the preceding  claims 89 - 90 , further comprising an initial step of grinding the inorganic particulate material in the absence of the fibrous substrate comprising cellulose to obtain an inorganic particulate material having a desired particle size. 
     
     
         92 . The method according to any one of the preceding  claims 89 - 91 , wherein the inorganic particulate material is an alkaline earth metal carbonate or sulphate, such as calcium carbonate, magnesium carbonate, dolomite, gypsum, a hydrous kandite clay such as kaolin, halloysite or ball clay, an anhydrous (calcined) kandite clay such as metakaolin or fully calcined kaolin, talc, mica, perlite or diatomaceous earth, or combinations thereof. In a preferred embodiment, the inorganic particulate material is an alkaline earth metal carbonate, for example, calcium carbonate or kaolin or a combination thereof. 
     
     
         93 . The method according to any one of the preceding  claims 79 - 88 , wherein the microfibrillating step comprises microfibrillating the fibrous substrate comprising cellulose in the aqueous environment by grinding in the presence of a grinding medium, and wherein the grinding is carried out in the absence of grindable inorganic particulate material.