WO2019086673A1

WO2019086673A1 - Cellulose powder compositions

Info

Publication number: WO2019086673A1
Application number: PCT/EP2018/080184
Authority: WO
Inventors: Paulus Pieter De Wit; Conrardus Hubertus Joseph Theeuwen; Franciscus Adrianus Ludovicus Maria STAPS; Gijsbert Adriaan VAN INGEN
Original assignee: Akzo Nobel Chemicals International B.V.; Koninklijke Coöperatie Cosun U.A.
Priority date: 2017-11-06
Filing date: 2018-11-05
Publication date: 2019-05-09

Abstract

The present invention relates to a powder composition comprising a cellulose component and a carboxycellulose component. The present inventors surprisingly found that combinations of certain cellulose components and carboxycelluloses can be processed into a powder composition that is easily (re)dispersible in water and aqueous systems to regain much of the cellulose component's original rheological performance. It is believed that in the compositions of the invention, the cellulose component primarily serves to confer the desired rheological/structuring properties while the carboxycellulose primarily serves to enable the cellulose component to be converted into a powder composition with very low water content that can be dispersed without the application of high mechanical shear forces while regaining most or all of the cellulose component's performance. The invention also provides a method for producing the powder composition. Furthermore the invention relates to uses of the powder composition.

Description

CELLULOSE POWDER COMPOSITIONS

Field of the invention

The present invention relates to a powder composition comprising a cellulose component and a carboxycellulose component. More in particular the invention relates to a powder composition that can easily be re-dispersed in water, while regaining most of its initial rheological performance. The invention also provides a method for producing such a powder composition. Furthermore the invention relates to uses of the powder compositions. Background art

Cellulose is a highly abundant organic polymer. It naturally occurs in woody and non-woody plant tissue, as well as in certain algae, oomycetes and bacteria. Cellulose has been used to produce paper and paperboard since ancient times. More recently cellulose (and its derivatives) gained substantial interest as rheology modifier.

Plant-derived cellulose is usually found in a mixture with hemicellulose, lignin, pectin and other substances, depending on the type of (tissue) cell from which it is derived. Plants form two types of cell wall that differ in function and in composition. Primary walls surround growing and dividing plant cells and provide mechanical strength but must also expand to allow the cell to grow and divide. Primary walls contain hemicellulose and pectin as the main constituents besides cellulose. The much thicker and stronger secondary wall, which accounts for most of the carbohydrate in biomass, is deposited once the cell has ceased to grow. The secondary walls are strengthened by the incorporation of large quantities of lignin.

In their natural form cellulose polymers stack together and form cellulose microfibrils. Where the cellulose polymers are perfectly stacked together, it creates highly crystalline regions. However, disorder in the stacking will also occur, creating amorphous regions in the microfibril. The crystalline regions in the microfibrils, and the very high aspect ratio, gives the material high strength. Various forms of processed cellulose have been developed having a much higher (relative) surface area than the cellulose raw material and therefore also a high number of accessible hydroxyl groups. Such materials have been found to possess beneficial rheological properties and have attracted much attention as viscosifying and/or structuring agents for aqueous systems in many fields of application. Important developments in this area started in the 1980's when materials were developed/disclosed by Turbak et al. (US4374702) and Weibel (EP0102829) denominated 'Microfibrillated cellulose' (MFC) and 'Parenchymal cell cellulose' (PCC) respectively.

MFC as developed by Turbak ef al. was obtained from secondary cell wall celluloses through a high-energy homogenization process. MFC is typically obtained from wood pulp, e.g. softwood sulphite pulp or Kraft pulp. The pulping process removes most of the encrusting lignin and hemicellulose from the secondary cell walls, so that nanofibrous cellulose can be liberated by treatments using high mechanical shear. MFC is a tangled mass of fibres with diameters typically in the range 20-100 nm and lengths of tens of micrometres, also referred to as 'nanofibers'. PCC as developed by Weibel is produced from primary cell wall (parenchymal cell wall) plant materials. PCC can be obtained from agricultural processing wastes, e.g. sugar beet pulp or potato pulp. The PCC initially developed by Weibel takes the form of parenchymal cell wall fragments, from which substantially all the other components making up the primary cell wall (pectin and hemicellulose) have been removed. According to Weibel these fragments have to be subjected to high shear homogenization treatment so as to distend and dislocate microfibrils in the cell membrane structure, creating so-called extended or hairy membranes, which constitutes the 'activated' form of the material.

Even though materials such as MFC and PCC initially seemed very promising, full scale production and actual commercialization has been seriously hampered. One of the challenges in commercializing MFC and PCC has been to develop a process for the treatment of the cellulose that is feasible on a large (commercial-scale) basis. The fibrillation of the cellulose, and the material handling during the process, can be a challenge. The major challenge in MFC/PCC development though is to provide (sufficiently) concentrated and/or dried forms of the material, that can be easily re- dispersed while regaining much of the material's initial performance. MFC and PCC are normally produced at a very low solid content, usually at a consistency (dry matter content) of between 1 % and 5% by weight. Higher dry matter content is needed for more feasible transportation and further processing. For example, in order to render distribution of the materials economically feasible even across continents, a dry matter content of at least 70 wt.% would be required. Upon increasing the dry matter content (DM) strong aggregation and changes on the fiber surface occur (a process called hornification), which makes re-dispersion / re-activation after drying difficult, if not impossible. On a pilot scale, MFC and/or PCC products have been provided in a wet state, typically as 'wet' concentrate, possessing e.g. up to 20 or 30 % DM. Such concentrates can still be re-activated to regain much of the initial performance. However, this requires the use of expensive equipment (such as high shear mixers) not typically available in standard formulation processes, and a substantial energy input. Additionally certain formulated products in which the PCC and/or MFC materials are to be applied cannot always accommodate the associated quantity of water. These aspects thus have hampered actual (commercial-scale) use of MFC, PCC and similar materials.

Unsurprisingly, this problem has been the subject of substantial research efforts, as is illustrated by the teachings of Dinand (US 5,964,983), who set out to develop a variant of Weibel's PCC that can be taken up into suspension after dehydration. According to Dinand this was accomplished by subjecting the parenchymal cell wall material to a process that, generally stated, involves less intense chemical treatment and more mechanical shear, as compared to Weibel's process. This results in a nanofibrillated product wherein some of the pectin and hemicelluloses is retained. The mechanical treatment results in the unraveling of cellulose.

In US 6,231 ,657 from Cantiani ef a/. , it is shown that the material developed by Dinand can in fact not be (easily) redispersed after dehydration/drying to (substantially) regain the beneficial rheological properties. In order to overcome this draw-back Cantiani proposes to combine Dinand's nanofibrilated product with a carboxycellulose. As can be seen in the experimental part, and as experienced by the present inventors, the materials developed by Cantiani still suffer from various shortcomings, such as the fact that they cannot be dried to a (sufficiently) high % DM and/or require the presence of further additives (at significant amounts) and/or cannot be re-dispersed easily and/or do not regain the rheological properties of the original PCC or MFC to a satisfactory extent. Almost twenty years after its original disclosure, the technology of US 6,231 ,657 has not resulted in a commercial 'easy-to-(re)disperse' MFC or PCC product.

It is an object of the present invention to provide materials that overcome some or all of the draw-backs encountered in the prior art methods. Summary of the invention

The present inventors surprisingly found that combinations of certain cellulose components and carboxycellu loses can be processed into a powder composition that is easily (re)dispersible in water and aqueous systems to regain much of the cellulose component's original rheological performance. Without wishing to be bound by any particular theory, the inventors believe that in the compositions of the invention, the cellulose component primarily serves to confer the desired rheological/structuring properties while the carboxycellulose primarily serves to enable the cellulose component to be converted into a powder composition with very low water content that can be dispersed without the application of high mechanical shear forces while regaining most or all of the cellulose component's performance. The precise interaction between the cellulose component and the carboxycellulose and/or the way in which they 'associate' in the product may not be fully understood. Satisfactory results have been obtained with various combinations of cellulose components and carboxycellu loses.

Hence, in an aspect of the invention, a powder composition is provided comprising water and at least 50 wt.% of dry matter, wherein the dry matter comprises a combination of i) a cellulose component, selected from activated/fibrillated plant or micro-organism derived cellulose materials, preferably from cellulose materials obtainable/obtained by (bio-)chemically extracting cellulose from plant tissue and subjecting it to mechanical/physical and/or enzymatic activation/fibrillation treatment, and ii) a carboxycellulose, characterized in that the powder composition can be dispersed in water at a concentration of the cellulose component of 1 % (w/v) by simple low shear mixing, e.g. by mixing, in a 400 ml beaker with a 70mm diameter ex Duran and at 25 °C, 200 ml of water with the corresponding amount of the powder using a R 1381 3-bladed Propeller stirrer ex IKA, placed 10 mm above the bottom surface, at 700 rpm for 120 minutes, to form a homogeneous structured system, without visually distinguishable solids or lumps, having a storage modulus (C) of at least 100 Pa and/or a yield point (YP) of at least 1 Pa and/or a viscosity at 0.01s^-1 of at least 200 Pa.s

In another aspect of the invention, a process for making said powder composition is provided, the process comprising the steps of:

a) providing an aqueous slurry comprising a mixture of an aqueous liquid and a cellulose component as defined herein having a dry matter content of at least 7.5 wt.%, preferably at least 10 wt.% or at least 20 wt.%; b) dispersing a quantity of a carboxycellulose into the aqueous slurry provided in step a), c) drying the composition as obtained in step b) at a product temperature not exceeding 120 °C; and

d) optionally grinding the dried product as obtained in step c) to the desired particle size, whereby step c) and d) can be combined into one step.

In another aspect of the invention, the use of the present powder compositions is provided for conferring structuring and/or rheological properties in aqueous products, such as detergent formulations, for example dishwasher and laundry formulations; in personal care and cosmetic products, such as hair conditioners and hair styling products; in fabric care formulations, such as fabric softeners; in paint and coating formulations as for example water-born acrylic paint formulations; food and feed compositions, such as beverages, frozen products and cultured dairy; pesticide formulations; biomedical products, such as wound dressings; construction products, as for example in asphalt, concrete, mortar and spray plaster; adhesives; inks; de-icing fluids; fluids for the oil & gas industry, such drilling, fracking and completion fluids; paper and cardboard or non-woven products; pharmaceutical products. Also they can be used to improve the mechanical strength, mechanical resistance and/or scratch resistance in ceramics, ceramic bodies, composites, and the like.

These and other aspects of the invention will become apparent on the basis of the following detailed description and the appended examples. Detailed description of the invention

The powder composition

A first aspect of the invention concerns a powder composition comprising water and at least 50 wt.% of dry matter, wherein the dry matter comprises a combination of i) a cellulose component, selected from activated/fibrillated plant or micro-organism derived cellulose materials, preferably from cellulose materials obtained/obtainable by (bio-)chemically extracting cellulose from plant tissue and subjecting it to mechanical/physical and/or enzymatic activation/fibrillation treatment, and ii) a carboxycellulose, characterized in that the powder composition can be dispersed in water at a concentration of the cellulose component of 1 % (w/v) by simple low shear mixing, e.g. by mixing, in a 400 ml beaker with a 70mm diameter ex Duran and at 25 °C, 200 ml of water with the corresponding amount of the powder using a R 1381 3-bladed Propeller stirrer ex IKA, placed 10 mm above the bottom surface, at 700 rpm for 120 minutes, to form a homogeneous structured system having a storage modulus (C) of at least 100 Pa and/or a yield point (YP) of at least 1 Pa and/or a viscosity at 0.01s^"1 of at Ieast200 Pa.s.

In accordance with embodiments of the invention, the powder composition is free flowing, meaning that the powder can be poured from a container in a continuous flow in which substantially the same mass leaves the container in the same time interval. In contrast, non-free-flowing materials will clump together to form aggregates of undefined size and weight and therefore cannot be poured from the container in a continuous flow in which substantially the same mass leaves the container in the same time interval. In embodiments of the invention at least 90% of separate and individual particles will remain separate and individual in a bulk container when stored over a period of 24 hours at ambient temperature and humidity (25 °C and 50% relative humidity).

Powder compositions can further be characterized by specific D10, D50 and D90 values. D10 is the particle size value that 10% of the population of particles lies below. D50 is the particle size value that 50% of the population lies below and 50% of the population lies above. D50 is also known as the median value. D90 is the particle size value that 90% of the population lies below. A powder composition that has a wide particle size distribution will have a large difference between D10 and D90 values. Likewise, a powder composition that has a narrow particle size distribution will have a small difference between D10 and D90. Particle size distribution may suitably be determined by using conventional tapped sieves. In embodiments of the invention a powder composition as defined herein is provided having a D50 of less than 800 μιτι, more preferably of less than 500 μιτι or less than 300 μιη. In embodiments of the invention a powder composition as defined herein is provided having a D50 of more than 50 μιτι, more preferably of more than 100 μιτι or more than 200 μιτι. In embodiments of the invention a powder composition as defined herein is provided having a D90 of less than 1500 μιτι, more preferably of less than 1000 μιτι or less than 750 μιτι. In embodiments of the invention a powder composition as defined herein is provided having a D90 of more than 5 μιτι, more preferably of more than 10 μιτι or more than 20 μιτι. In embodiments of the invention a powder composition as defined herein is provided having a D10 of less than 250 μιτι, more preferably of less than 200 μιτι or less than 150 μιτι. In embodiments of the invention a powder composition as defined herein is provided having a D50 of more than 25 μιτι, more preferably of more than 50 μιτι or more than 75 μιτι. In embodiments of the invention the D90 is no more than 200% greater than D10, preferably no more than 150% greater than D10, or no more than 100% greater than D10.

As will be understood by those skilled in the art on the basis of the present disclosure, it is a particular advantage of the present invention that suitable powder compositions can be provided having a low water content. In embodiments of the invention, the powder composition according to the present invention has a water content of less than 30 wt.%, less than 25 wt.%, less than 20 wt.%, less than 15 wt.%, less than 12.5 wt.%, less than 10 wt.%, less than 8 wt.%, less than 7 wt.%, less than 6 wt.% or less than 5 wt.%. Such powders are economically transported and handled. In embodiments of the invention, the powder composition comprises more than 70 wt.% of dry matter, preferably more than 75 wt.%, more than 80 wt.%, more than 85 wt.%, more, more than 87.5 wt.%, more than 90 wt.% , more than 92 wt.% , more than 93 wt.% , more than 94 wt.% or less than 95 wt.%. In embodiments of the invention, the powder composition comprises up to 99.9, 99.5, 99, 98, 97, or 95 wt.% of dry matter.

It was surprisingly found that powder compositions in accordance with the invention are not only easily dispersed, while still being able to provide the desired rheological effect, but also have an low water activity. This has the particular advantage that the powder compositions will have good microbial stability. A preferred method for determining the water activity of a sample is to bring a quantity of the sample in a closed chamber having a relatively small volume, measuring the relative humidity as a function of time until the relative humidity has become constant (for instance after 30 minutes), the latter being the equilibrium relative humidity for that sample. Preferably, a Novasina TH200 Thermoconstanter is used, of which the sample holder has a volume of 12 ml and which is filled with 3 g of sample. In embodiments of the invention, powder compositions as defined herein are provided having a water activity (Aw), defined as the equilibrium relative humidity divided by 100%, of less than 0.7, less than 0.6, less than 0.5, less than 0.4 or less than 0.3.

The surprising low water activity of the powders allows them to be made, shipped and used without the need to add biocides. This has advantages not only from an ecological perspective but also allows the use of the powders, or dispersions thereof in applications wherein biocides are undesired. Accordingly, embodiments of the invention are also provided wherein the powder composition is substantially or entirely free from biocides, e.g. the powder contains less than 2.5 wt.%, based on total dry weight, of biocides, preferably less than 1.5 wt.%, less than 1 wt.%, less than 0.5 wt.%, less than 0.25 wt.%, less than 0.1 wt.%, less than 0.05 wt.%, less than 0.01 wt.% or about 0 wt.%.

As will be evident from the foregoing, a particular advantage of the powder composition according to the present invention is that they can be dispersed in water or aqueous systems without having to apply high-intensity mechanical treatment to form a homogenous structured system.

Typically, in accordance with the invention, these beneficial properties can be established using simple testing methods. In particular, the powder compositions of the invention can be dispersed at a concentration of the cellulose component of 1 wt.% (w/v) in water by mixing a corresponding amount of the powder in 200 ml of water in a 400 ml beaker having a 70 mm diameter (ex Duran) and a propeller stirrer equipped with three paddle blades each having a radius of 45 mm, for instance a R 1381 3-bladed propeller stirrer ex IKA (Stirrer 0: 45 mm Shaft 0: 8 mm Shaft length: 350 mm), placed 10 mm above the bottom surface and operated at 700 rpm for 120 minutes, at 25 °C. With such a setup, the powder composition will be completely dispersed within the 120 minutes, at 25 °C, where completely dispersed means that no solids or lumps can be visually distinguished anymore. Furthermore, a dispersion of the present powder composition in water, at a concentration of the cellulose component of 1 % (w/v) prepared using this particular protocol has one or more of the rheological characteristics described in the subsequent paragraphs.

In embodiments of the invention, a dispersion of the present powder composition in water, at a concentration of the cellulose component of 1 % (w/v), obtained using the above described protocol shows no syneresis after standing for 16 hours at 25 °C in a 200 ml graduated cylinder of about 300mm height. Within the context of the present invention, "no syneresis" means that if a layer of water is formed on top of the dispersion it is less than 1 mm or that no such layer of water is distinguishable at all.

The structured system obtained when dispersing the powder composition at a concentration of the cellulose component of 1 % (w/v) in water, according to the above described protocol, typically will take the form of a viscoelastic system or a gel. Typically, the viscoelastic behavior of these systems can be further determined and quantified using dynamic mechanical analysis where an oscillatory force (stress) is applied to a material and the resulting displacement (strain) is measured. The term "Storage modulus", G', also known as "elastic modulus", which is a function of the applied oscillating frequency, is defined as the stress in phase with the strain in a sinusoidal deformation divided by the strain; while the term "Viscous modulus", G", also known as "loss modulus", which is also a function of the applied oscillating frequency, is defined as the stress 90 degrees out of phase with the strain divided by the strain. Both these moduli, are well known within the art, for example, as discussed by G. Marin in "Oscillatory Rheometry", Chapter 10 of the book on Rheological Measurement, edited by A. A. Collyer and D. W. Clegg, Elsevier, 1988. In the art, gels are defined to be those systems for which G'>G".

In embodiments of the invention, a dispersion of the present powder composition in water, at a concentration of the cellulose component of 1 % (w/v), obtained using the above described protocol, has a storage modulus G' of at least 100 Pa, more preferably at least 1 10 Pa, at least 120 Pa, at least 130 Pa, at least 140 Pa or at least 150 Pa. In embodiments of the invention the storage modulus G' of said dispersion is 500 Pa or less, e.g. 400 Pa or less, or 300 Pa or less.

In embodiments of the invention, a dispersion of the present powder composition in water, at a concentration of the cellulose component of 1 % (w/v), obtained using the above described protocol has a storage modulus G' that is higher than the loss modulus G". More preferably a dispersion of the present powder composition in water, at a concentration of the cellulose component of 1 % (w/v), obtained using the above described protocol, has a loss modulus G" of at least 10 Pa, more preferably at least, 12.5 Pa, at least 15 Pa, at least 17.5 Pa or at least 20 Pa. In embodiments of the invention the loss modulus G" of said dispersion is 100 Pa or less, e.g. 75 Pa or less, or 50 Pa or less.

In embodiments of the invention, a dispersion of the present powder composition in water, at a concentration of the cellulose component of 1 % (w/v), obtained using the above described protocol has a flow point (at which G'= G") of at least 10 Pa, more preferably at least, 12.5 Pa, at least 15 Pa, at least 17.5 Pa or at least 20 Pa. In embodiments of the invention the flow point of said dispersion is 75 Pa or less, e.g. 50 Pa or less, or 30 Pa or less. The flow point is the critical shear stress value above which a sample Theologically behaves like a liquid; below the flow point it shows elastic or viscoelastic behavior.

In an embodiment of the invention, a dispersion of the present powder composition in water, at a concentration of the cellulose component of 1 % (w/v), obtained using the above described protocol has a yield point of at least 1 Pa, preferably at least 1.5 Pa, at least 2.0 Pa, at least 2.5 Pa or at least 3 Pa. In embodiments of the invention the Yield point of said dispersion is 10 Pa or less, e.g. 7 Pa or less, 6 Pa or less or 5 Pa or less. The yield point is the lowest shear stress, above which a sample shows an irreversible structural change; below the yield point it shows reversible elastic or viscoelastic behavior. Between the yield point and the flow point is the yield zone. In an embodiment of the invention, a dispersion of the present powder composition in water at 25 °C, at a concentration of the cellulose component of 1 % (w/v), obtained using the above described protocol has a viscosity at 0.01s-¹ of at least 150 Pa.s, preferably at least 200 Pa.s, at least 250 Pa.s or at least 300 Pa.s. In embodiments of the invention said dispersion has a viscosity at 0.01 s of 750 Pa.s or less, e.g. 600 Pa.s or less or 500 Pa.s or less. In embodiments of the invention, a dispersion of the present powder composition in water, at a concentration of the cellulose component of 1 % (w/v), obtained using the above described protocol is shear thinning. Shear thinning, as used herein, means that the fluid's resistance to flow decreases with an increase in applied shear stress. Shear thinning is also referred to in the art as pseudoplastic behavior. Shear thinning can be quantified by the so called "shear thinning factor" (SF) which is obtained as the ratio of viscosity at 1 s^~ and at 10 s^~ : A shear thinning factor below zero (SF<0) indicates shear thickening, a shear thinning factor of zero (SF=0) indicates Newtonian behavior and a shear thinning factor above zero (SF>0) stands for shear thinning behavior. In an embodiment of the invention the shear thinning property is characterized by the structured system having a specific pouring viscosity, a specific low-stress viscosity, and a specific ratio of these two viscosity values.

In embodiments of the invention, a dispersion of the present powder composition in water, at a concentration of the cellulose component of 1 % (w/v), obtained using the above described protocol has a pouring viscosity ranging from 25 to 2500 mPa s, preferably from 50 to 1500 mPa s, more preferably from 100 to 1000 mPa s. The pouring viscosity, as defined herein, is measured at a shear rate of 20 s^" .

As will be understood by those skilled in the art, rheological characteristics of the re-dispersed powder composition, determined in accordance with above-defined protocol, can be compared with that of a dispersion of a corresponding combination of the cellulose component and the carboxycellulose before/without drying into a powder, so as to assess the extent to which the rheological performance is regained after drying and re-dispersion according to the present invention.

Accordingly, embodiments are provided, wherein the storage modulus G' of a re-dispersed powder composition, determined in accordance with above-defined protocol, is X, whereby the storage modulus G' of an aqueous dispersion of the corresponding combination of the cellulose component and the carboxycellulose without/before drying is less than 2X, preferably less than 1.75X, more preferably less than 1.5X, more preferably less than 1.4X, more preferably less than 1.3X, more preferably less than 1.2X, more preferably less than 1.1X. For such powder compositions the remarkable good rheological property retention, when compared to the composition before drying, allows an economic handling of the composition without that undesired laborious and energy-intensive activation processes are needed.

Furthermore, embodiments are provided, wherein the Yield Point of a re-dispersed powder composition, determined in accordance with above-defined protocol, is Y whereby the yield point of an aqueous dispersion of the corresponding combination of the cellulose component and the carboxycellulose without/before drying is less than 2Y, preferably less than 1.75Y, more preferably less than 1.5Y, more preferably less than 1.4Y, more preferably less than 1.3Y, more preferably less than 1.2Y, more preferably less than 1.1Y.

Furthermore, embodiments are provided, wherein the viscosity of a re-dispersed powder composition, determined in accordance with above-defined protocol, is Z whereby the viscosity of an aqueous dispersion of the corresponding combination of the cellulose component and the carboxycellulose without/before drying is less than 2Z, preferably less than 1.75Z, more preferably less than 1.5Z, more preferably less than 1.4Z, more preferably less than 1.3Z, more preferably less than 1.2Z, more preferably less than 1.1Z.

Unless indicated otherwise, viscosity and flow behavior measurements, in accordance with this invention, are performed at 20 °C, using an Anton Paar rheometer, Physica MCR 301 , with a 50mm plate-plate geometry (PP50) and a gap of 1 mm. For amplitude sweep testing the angular frequency is fixed at 10 s^~ and the strain amplitude (γ) is from 0.01 % to 500%. Rheology parameters defined herein concern the structured system obtained when dispersing the powder composition in water according to the above described protocol. The presence of other components in the aqueous system can influence certain rheology measurements.

A preferred powder composition according to the present invention comprises on a dry weight basis 20-80 wt.% of the cellulose component and 20-80 wt.% of the carboxycellulose. A more preferred powder composition comprises on a dry weight basis 40-70 wt.% of the cellulose component and 30-60 wt.% of the carboxycellulose. A more preferred powder composition comprises on a dry weight basis 50-70 wt.% of the cellulose component and 30-50 wt.% of the carboxycellulose. A preferred powder composition according to the present invention comprises the cellulose component and the carboxycellulose at a weight ratio within the range of 20/80 to 80/20, preferably with the range of 40/60 to 70/30, more preferably within the range of 50/50 to 70/30.

In embodiments of the invention, the powder composition comprises more than 30 wt.%, on a dry weight basis, of the carboxycellulose, e.g. more than 31 wt.%, more than 32 wt.% more than 33 wt.% more than 34 wt.% or more than 35 wt.%.

In embodiments of the invention, the cellulose component and the carboxycellulose constitute at least 80 wt.% of the dry solids weight of the powder composition, e.g. at least 85 wt.%, at least 90 wt.%, at least 95 wt.%, at least 96 wt.%, at least 97 wt.% , at least 98 wt.% , at least 99 wt.% or at least 99.5 wt.% of the powder composition.

In preferred embodiments the cellulose component and the carboxycellulose are at least in part in chemical association, typically by hydrogen bonding or by electrostatic interaction. In particular embodiments at least part of the carboxycellulose forms a layer covering and/or shielding at least part of the surface of the cellulose component structures. The cellulose component

In accordance with the invention, a cellulose component is used that has the capability to modify the rheological properties of aqueous systems. Broadly stated, the cellulose component is an activated/fibrillated plant or micro-organism derived cellulose material, preferably a cellulose material obtained by (bio-)chemically extracting cellulose from plant tissue and subjecting it to mechanical/physical and/or enzymatic activation/fibrillation treatment.

This thus embraces PCC and MFC materials, such as those disclosed in the prior art discussed herein, as well as other similarly treated plant derived cellulosic materials and bacterial cellulose.

As is understood by those skilled in the art, the term "(bio-)chemically treated" refers to (generally known) treatments that result primarily in the removal of non-cellulosic components of parenchymal and non-parenchymal plant tissue, such as pectin and hemicellulose in the case of parenchymal cellulose material, and lignin and hemicellulose in the case of materials derived from woody plant parts, which can be done chemically, enzymatically or through fermentation. In accordance with the invention, such treatments do not result in appreciable degradation or modification of the cellulose and/or in a substantial change in the degree and type of crystallinity. The terms "mechanical/physical activation/fibrillation treatment" refers to (generally known) treatments, typically involving subjecting the cellulose material to high mechanical or physical (shear) forces, that alter the morphology of the cellulose, typically through the partial, substantial or complete liberation of cellulose microfibrils from the cellulose fiber structure and/or the opening up of the cellulose fiber network structure, thereby significantly increasing the specific surface area thereof. This treatment may be referred to as the 'activation' treatment, as it is the treatment whereby the cellulose material actually gains its beneficial rheological profile. As is known by those skilled in the art, similar changes in the morphology and/or functional properties of the cellulose material can be brought about using certain enzymatic procedures, known as HefCel treatment. This treatment is referred to herein as "enzymatic activation/fibrillation treatment".

Accordingly, in embodiments of the invention, the cellulose component is an activated/fibrillated plant or micro-organism derived cellulose material comprising, on a dry weight basis, at least 50 wt.%, at least 60 wt.%, at least 70 wt,%, at least 75 wt.%, at least 80 wt.%, at least 85 wt.%, at least 90 wt.% or at least 95 wt.% of cellulose.

Furthermore, in embodiments of the invention, the cellulose component is an activated/fibrillated plant or micro-organism derived cellulose material comprising cellulose with a crystallinity index calculated (according to the Hermans-Weidinger method) below 75 %, below 60 %, below 55 %, below 50 % or below 45 %. In embodiments of the invention, the crystalline regions of the cellulose are primarily or entirely of the type I, which embraces types l_a and lp, as can be determined by FTIR spectroscopy and/or X-ray diffractometry.

Furthermore, the invention provides embodiments wherein the cellulose component is an activated/fibrillated plant or micro-organism derived cellulose material comprising cellulose with a specific surface as determined using a Congo red dye adsorption method (Goodrich and Winter 2007; Ougiya et al. 1998; Spence et al. 2010b). In some embodiments of the invention, said specific surface area is at least 30 m²/g, at least 35 m²/g, at least 40 m²/g, at least 45 m²/g, at least 50 m²/g, or at least 60 m²/g. In some embodiments of the invention, said specific surface area is at least 4 times higher than that of native cellulose, e.g. at least 5 times, at least 6 times, at least 7 times or at least 8 times.

In embodiments of the invention, the cellulose component is characterized by certain rheological characteristics, which can be determined, for instance, for a 1 % (w/v) homogeneous dispersion of the cellulose component in water, e.g. using a protocol identical to what is described herein elsewhere in relation to the powder composition per se.

In accordance with the invention, embodiments are provided wherein a cellulose component is used, of which a 1 wt.% dispersion in water has a storage modulus G' of at least 100 Pa, more preferably at least 1 10 Pa, at least 120 Pa, at least 130 Pa, at least 140 Pa or at least 150 Pa. In embodiments of the invention the storage modulus G' of said dispersion is 500 Pa or less, e.g. 400 Pa or less, or 300 Pa or less. In accordance with the invention, embodiments are provided wherein a cellulose component is used, of which a 1 wt.% dispersion in water has a storage modulus G' that is higher than the loss modulus G". More preferably such a 1 wt.% dispersion has a loss modulus G" of at least 10 Pa, more preferably at least, 12.5 Pa, at least 15 Pa, at least 17.5 Pa or at least 20 Pa. In embodiments of the invention the loss modulus G" of said dispersion is 100 Pa or less, e.g. 75 Pa or less, or 50 Pa or less.

In accordance with the invention, embodiments are provided wherein a cellulose component is used, of which a 1 wt.% dispersion in water has a flow point (at which G'= G") of at least 10 Pa, more preferably at least, 12.5 Pa, at least 15 Pa, at least 17.5 Pa or at least 20 Pa. In embodiments of the invention the flow point of said dispersion is 75 Pa or less, e.g. 50 Pa or less, or 30 Pa or less. In accordance with the invention, embodiments are provided wherein a cellulose component is used, of which a 1 wt.% dispersion in water has a yield point of at least 1 Pa, preferably at least 1.5 Pa, at least 2.0 Pa, at least 2.5 Pa or at least 3 Pa. In embodiments of the invention the Yield point of said dispersion is 10 Pa or less, e.g. 7 Pa or less, 6 Pa or less or 5 Pa or less.

In accordance with the invention, embodiments are provided wherein a cellulose component is used, of which a 1 wt.% dispersion in water has a viscosity of at 0.01 s^~ of at least 150 Pa.s, preferably at least 200 Pa.s, at least 250 Pa.s or at least 300 Pa.s. In embodiments of the invention said dispersion has a viscosity at 0.01 s^~ of 750 Pa.s or less, e.g. 600 Pa.s or less or 500 Pa.s or less. In embodiments of the invention, the cellulose component is microfibrillated cellulose (MFC). Although the term "microfibrillated cellulose" is known to persons of ordinary skill in the art and has been well- described in literature, for purposes of the presently disclosed and/or claimed inventive concept(s), the term "microfibrillated cellulose (MFC)" in the context of the present invention is defined as cellulose consisting (substantially) of microfibrils in the form of either isolated cellulose microfibrils and/or microfibril bundles of cellulose, both of which are derived from a cellulose raw material. MFC microfibrils typically have a high aspect ratio. Microfibrillated cellulose typically has a diameter of 10- 300 nm, preferably 25-250 nm, more preferably 50-200 nm, and a length of several micrometers, preferably less than 500 μιτι, more preferably 2-200 μιτι, even more preferably 10-100 μιτι, most preferably 10-60 μιτι. Microfibrillated cellulose often comprises bundles of 10-50 microfibrils. Microfibrillated cellulose may have a high degree of crystallinity and a high degree of polymerization, for example the degree of polymerisation DP, i.e. the number of monomeric units in a polymer, may be 100-3000. As used herein, "microfibrillated cellulose" can be used interchangeably with "microfibrillar cellulose," "nanofibrillated cellulose," "nanofibril cellulose," "nanofibers of cellulose," "nanoscale fibrillated cellulose," "microfibrils of cellulose," and/or simply as "MFC" and/or "NFC". Additionally, as used herein, the terms listed above that are interchangeable with "microfibrillated cellulose" may refer to cellulose that has been completely microfibrillated or cellulose that has been substantially microfibrillated but still contains an amount of non-microfibrillated cellulose at levels that do not interfere with the benefits of the microfibrillated cellulose as described and/or claimed herein. The microfibrillated cellulose may be formed from one or more cellulose-containing raw materials including, for example but without limitation, (a) wood-based raw materials like hardwoods and/or softwoods, (b) plant-based raw materials, such as chicory, beet root, turnip, carrot, potato, citrus, apple, grape, tomato, grasses, such as elephant grass), straw, bark, caryopses, cotton, maize, wheat, oat, rye, barley, rice, flax, hemp, abaca, sisal, kenaf, jute, ramie, bagasse, bamboo, reed, algae, fungi and/or combinations thereof, (c) recycled fibers from, for example but without limitation, newspapers and/or other paper products, and/or (d) bacterial cellulose.

Preferably a chemical pulp, further preferably bleached, half-bleached and unbleached sulphite, sulphate and soda pulps, Kraft pulps together with unbleached, half-bleached and bleached chemical pulps, and mixtures of these are used to produce MFC. A particularly preferred source of cellulose is regular, fiber-length pulp, derived from either hardwood or soft-wood, or both types (in mixtures), normally available from a pulping operation, or pre-cut if desired. Preferably, said pulp contains pulp from soft-wood. The pulp may also contain soft-wood of one kind only or a mixture of different soft-wood types.

The microfibrillated cellulose may be produced by any high shear treatment as would be known to a person of ordinary skill in the art. In particular, the microfibrillated cellulose may be produced by a method selected from grinding (using e.g. a disc grinder); sonication (such as sonication employing ultrasound); homogenization; heat; steam explosion; pressurization- depressurization cycle; freeze-thaw cycle; mixing (such as impingement mixing); microwave explosion; and/or milling. Various combinations of these may also be used, such as milling followed by homogenization. In one embodiment, the at least one microfibrillated cellulose is formed by subjecting one or more cellulose-containing raw materials to a sufficient amount of shear in an aqueous suspension such that a portion of the crystalline regions of the cellulose fibers in the one or more cellulose-containing raw materials are fibrillated. Pre-treatments are sometimes used to reduce the high energy consumption. Preferably, said composition is produced by subjecting a fiber material to a mechanical pretreatment step, in particular a refining step and, in a subsequent step, subjecting the product obtained in said first step to a homogenizer. Mechanical pretreatment steps, in particular refining steps and homogenizing steps that may be used for producing the composition of microfibrillated cellulose in liquid are known in the art. In embodiments of the invention, the cellulose component is a bacterial cellulose. The term "bacterial cellulose" is intended to encompass any type of cellulose produced via saccharide fermentation by a suitable species of bacteria, such as Acetobacter, Azotobacter, Rhizobium, Pseudomonas, Salmonella and Alcaligenes. Bacterial cellulose is typically activated by processing of a mixture of the bacterial cellulose in a hydrophilic solvent, such as water, polyols (e.g., ethylene glycol, glycerin, polyethylene glycol, etc.), or mixtures thereof. This processing comprises, generally, high pressure homogenization and/or high shear mixing. Such intense processing expands the cellulose portion to create a bacterial cellulose network, which is a reticulated network of highly intermeshed fibers with a very high surface area. The activated reticulated bacterial cellulose possesses an extremely high surface area. An example of a bacterial cellulose that may suitably be utilized herein is obtained by fermentation using Acetobacter genus microorganisms, as is commercially available from CPKelco, under the tradename Cellulon.

In embodiments of the invention, the cellulose component is a parenchymal cell cellulose (PCC). As used herein, the term "parenchymal cell cellulose" generally refers to cellulose components as defined herein before derived from parenchymal tissue containing plant parts. Parenchymal cell walls, which may also be referred to as "primary cell wall', contain relatively thin cell walls (compared to secondary cell walls) which are tied together by pectin (as opposed to secondary cell walls that are much thicker than parenchymal cells and are linked together with lignin). Parenchymal tissue containing plant parts, in the context of the present invention, can e.g. be chicory, beet root, turnip, carrot, potato, citrus, apple, grape, or tomato. In a particularly preferred embodiment of the invention, the parenchymal cellulose material is obtained from sugar beet, e.g. as a by-product of sucrose production.

In preferred embodiments of the invention, the parenchymal cell cellulose comprises, on a dry weight basis, at least 50 wt.%, at least 60 wt.%, at least 70 wt,%, at least 75 wt.%, at least 80 wt.%, at least 85 wt.%, at least 90 wt.% or at least 95 wt.% of cellulose. In a particularly preferred embodiment of the invention, the cellulose component is a processed parenchymal cell cellulose material containing, by dry weight, at least 50 % cellulose, 0.5-10 % pectin and 1-15 % hemicellulose. The term "pectin" as used herein refers to a class of plant cell-wall heterogeneous polysaccharides that can be extracted by treatment with acids and chelating agents. Typically, 70-80% of pectin is found as a linear chain of o(1-4)-linked D-galacturonic acid monomers. It is preferred that the parenchymal cellulose material comprises 0.5-5 wt.% of pectin, by dry weight of the cellulose material, more preferably 0.5- 2.5 wt.%. The term "hemicellulose" refers to a class of plant cell-wall polysaccharides that can be any of several homo- or heteropolymers. Typical examples thereof include xylane, arabinane xyloglucan, arabinoxylan, arabinogalactan, glucuronoxylan, glucomannan and galactomannan. Monomeric components of hemicellulose include, but are not limited to: D-galactose, L-galactose, D-mannose, L- rhamnose, L-fucose, D-xylose, L-arabinose, and D-glucuronic acid. This class of polysaccharides is found in almost all cell walls along with cellulose. Hemicellulose is lower in weight than cellulose and cannot be extracted by hot water or chelating agents, but can be extracted by aqueous alkali. Polymeric chains of hemicellulose bind pectin and cellulose in a network of cross-linked fibers forming the cell walls of most plant cells. Preferably the parenchymal cellulose material comprises, by dry weight of the cellulose material, 1-15 wt.% hemicellulose, more preferably 1-10 wt.% hemicellulose, most preferably 1-5 wt.% hemicellulose.

In a particularly preferred embodiment of the invention, the parenchymal cell cellulose is obtainable by a method comprising the steps of a1 ) providing a parenchymal cellulose containing vegetable pulp; a2) subjecting the parenchymal cellulose containing vegetable pulp to (bio-)chemical treatment, e.g. treatment with an acid, alkali and/or oxidizing agent, resulting in partial degradation and/or extraction of pectin and hemicellulose; a3) subjecting the material resulting from step a2) to a high shear process whereby the particle size of the cellulose material is reduced so as to yield a material having a median major dimension (D[4,3]), within the range of 15-75 μιτι, as measured using laser diffraction particle size analysis. A suitable apparatus for this (and other) particle size characteristics is a Malvern Mastersizer 3000 obtainable from Malvern Instruments Ltd., Malvern UK, using a Hydro MV sample unit (for wet samples). In preferred embodiments of the invention, the reported median major dimension within the range of 20-65 μιτι or 25-50 μιτι. Typically, the reported D90 is less than 120 μιτι, more preferably less than 1 10 μιτι, more preferably less than 100 μιτι. Typically the reported D10 is higher than 5 μιτι, more higher than 10 μιτι, more preferably higher than 25 μιτι. In an embodiment, In accordance with certain embodiments, the mechanical and/or physical treatment does not result in the complete or substantial unraveling to nanofibrils. Hence, in embodiments of the invention the cellulose component comprises less than 50 wt.%, less than 40 wt.%, less than 30 wt.%, less than 20 wt.%, less than 15 wt.% or less than 10 wt.% of unravelled nanofibrils.

The carboxycellulose

As used herein, the term carboxycellulose refers to derivatives of cellulose comprising carboxylic acid groups bound to some of the hydroxyl groups of the cellulose monomers, usually by means of a linking group, wereby the anionic carboxy groups typically renders the derivative to become water soluble. In accordance with the invention, the carboxycellulose preferably is carboxymethylcellulose (CMC), although other variants may also suitably be used. The carboxylic acid groups may also be (partially) present in the salt and/or ester form. Suitably the sodium salt of a carboxycellulose is used. All of such compounds are herein defined to be anionic.

In accordance with the invention, the carboxycellulose, in particular the carboxymethyl cellulose (CMC), suitably has a degree of substitution of the carboxy-containing groups ranging between 0.2 and 1.5. In an embodiment of the invention, the degree of substitution is at least 0.3, at least 0.4, at least 0.5 or at least 0.6. In an embodiment of the invention, the degree of substitution is less than 1.4, less than 1.3, less than 1.2, less than 1.1 , less than 1 .0, or less than 0.9. The degree of substitution corresponds to the average number of substituent groups (in particular carboxymethyl groups) attached per number of carboxyl groups (in particular carboxymethyl groups) per anhydrous glucose unit (AGU) of the cellulose.

The carboxycellulose of this invention can contain non-ionic groups such as alkyl or hydroxy alkyl groups, e.g. hydroxymethyl, hydroxyethyl, hydroxypropyl, hydroxylbutyl and mixtures thereof, e.g. hydroxyethyl methyl, hydroxypropyl methyl, hydroxybutyl methyl, hydroxyethyl ethyl, hydroxypropyl ethyl and mixtures thereof. In an embodiment of the invention, the carboxycellulose contains both carboxy and non-ionic groups, as in carboxymethyl hydroxyethyl cellulose, carboxymethyl ethyl cellulose, carboxymethyl ethyl hydroxyethyl cellulose.

The carboxycellulose may also contain cationic groups as long as the overall charge is net anionic, i.e. the degree of substitution with anionic groups and cationic groups is such that the net charge is anionic. In an embodiment, the anionic polysaccharide is free or substantially free from cationic groups. The cationic groups are suitably bonded to the cellulose back bone with a linking group, which may be substituted, as in linkages containing amine and/or amido functions. Suitable cationic groups include salts of amines, suitably salts of tertiary amines, and quaternary ammonium groups, preferably quaternary ammonium groups. The substituents attached to the nitrogen atom of amines and quaternary ammonium groups can be same or different and can be selected from alkyl, cycloalkyl, and alkoxyalkyl, groups, and one, two or more of the substituents together with the nitrogen atom can form a heterocyclic ring. The substituents independently of each other usually comprise from 1 to about 24 carbon atoms, preferably from 1 to about 8 carbon atoms. The nitrogen of the cationic group can be attached to the polysaccharide by means of a chain of atoms which suitably comprises carbon and hydrogen atoms, and optionally O and/or N atoms. Usually the chain of atoms is an alkylene group with from 2 to 18 and suitably 2 to 8 carbon atoms, optionally interrupted or substituted by one or more heteroatoms, e.g. O or N such as alkyleneoxy group or hydroxy propylene group. Preferred anionic polysaccharides containing cationic groups include those obtained by reacting the anionic polysaccharide with a quaternization agent selected from 2, 3-epoxypropyl trimethyl ammonium chloride, 3-chloro-2-hydroxypropyl trimethyl ammonium chloride and mixtures thereof.

The carboxycellulose may also contain further anionic groups, such as sulphate, sulphonate, phosphate and phosphonate groups, suitably these groups are directly bonded to the cellulose backbone, or they are also linked to the cellulose back bone with a linking group.

Suitable linking groups of the invention are alkyl groups, such as methyl, ethyl, propyl and mixtures thereof, typically methyl, as in CMC.

As will be apparent to those of average skill in the art suitable carboxycellulose products are commercially available, such as the Akucell®, Depramin®, Peridur®, Staflo®, Gabroil® and Gabrosa® product ranges from AkzoNobel.

The molecular weight of the carboxycellulose, expressed as the weight averaged molecular weight (Mw), is not very critical. Suitably products ranging from very low viscosity grades with a typical Mw of 2.000 Dalton up to ultra-high viscosity grades, such as those with a Mw of 10,000.000 Dalton, are used. In an embodiment the Mw is less than 2,500,000, 1 ,000,000, 500,000, 350,000, 250,000 or 200,000 Dalton for ease of dissolution. In an embodiment the Mw is more than 5,000, 20,000, 75,000, 125,000, 150,000, or more than 175,000 for higher viscosity of the end-product after dissolution.

Process for producing a powder composition

a) providing an aqueous slurry comprising a mixture of an aqueous liquid and a cellulose component as defined herein, said slurry having a dry matter content of at least 7.5 wt.%, preferably at least 10 wt.% or at least 20 wt.%;

b) dispersing a quantity of a carboxycellulose into the aqueous slurry provided in step a), c) drying the composition as obtained in step c) at a product temperature not exceeding 120 °C; and

d) optionally grinding the dried product as obtained in step c) to the desired particle size, whereby step c) and d) can be combined into one step. The slurry comprising the cellulose component - Step a)

In accordance with the invention, step a), generally stated, comprises providing an aqueous slurry comprising a cellulose component as defined herein before, at a concentration of at least 7.5 wt.% or at least 10 wt.%, or at least 20 wt.%, in an aqueous liquid, preferably in water. As will be understood by those skilled in the art based on the foregoing, suitable cellulose components, such as

MFC, PCC and/or activated bacterial cellulose, will typically be produced in the form of an aqueous slurry, as they are very difficult to concentrate or dry per se. Hence, in accordance with the invention, step a) may typically entail the process of producing the cellulose component from a natural source, i.e. by (bio-)chemical extraction from plant tissue followed by mechanical/physical and/or enzymatic activation/fibrillation treatment.

In a particularly preferred embodiment, step a) comprises the production of an aqueous slurry comprises a mixture of an aqueous liquid and a cellulose component, by:

a1 ) providing a parenchymal cellulose containing plant pulp;

a2) subjecting the parenchymal cellulose containing vegetable pulp to (bio-)chemical treatment resulting in partial degradation and/or extraction of pectin and hemicellulose;

a3) subjecting the material resulting from step a2) to mechanical/physical and/or enzymatic activation/fibrillation treatment; and

a4) concentrating the material as obtained in step a3) to a dry matter content of at least 7.5 wt.% w/w, preferably at least 10 wt.%, more preferably at least 20 wt.%.

The parenchymal cell containing plant pulp used as the starting material typically comprises an aqueous slurry comprising ground and/or cut plant materials, which often can be derived from waste streams of other processes, such as spent sugar beet pulp derived from conventional (sucrose) sugar production. Particularly preferred is the use of fresh, pressed-out sugar beet pulp from which the sugars have been extracted and which has a dry solids content of 10-50 wt.%, preferably 20-30 wt.%, for example approximately 25 wt.%. Sugar beet pulp is the production residuum from the sugar beet industry. More specifically, sugar beet pulp is the residue from the sugar beet after the extraction of sucrose there from. Sugar beet processors usually dry the pulp. The dry sugar beet pulp can be referred to as "sugar beet shreds". Additionally, the dry sugar beet pulp or shreds can be formed and compressed to produce "sugar beet pellets". These materials may all be used as the starting material, in which case step a) will comprise suspending the dry sugar beet pulp material in an aqueous liquid, typically to the afore-mentioned dry solids contents. Preferably however, fresh wet sugar beet pulp is used as the staring material.

Another preferred starting material is ensilaged pulp, especially ensilaged sugar beet pulp. As used herein, the term "ensilage" refers to the process of storing vegetable materials in a moist state under conditions resulting in acidification caused by anaerobic fermentation of carbohydrates present in the materials being treated. Ensilage is carried out according to known methods with pulps preferably containing 15 to 35% of dry matter. Ensilage of sugar beets is continued until the pH is within the range of 3.5-5. It is known that pressed beet pulps may be ensilaged to protect them from unwanted decomposition and avoid growth of pathogenic bacteria and moulds. This process is most commonly used to protect this perishable product, the other alternative being drying to 90% dry matter. This drying has the disadvantage of being very energy-intensive. The fermentation process starts spontaneously under anaerobic conditions with the lactic acid bacteria being inherently present. These microorganisms convert the residual sucrose of the pressed beet pulp to lactic acid, causing a fall in the pH and a strong reduction of the oxygen content. The storing of the sugar beet pulp under these conditions was found to confer specific characteristics that are advantageous with a view to the further processing of the material according to the method as defined herein and/or with a view of the characteristics of the material obtained accordingly. Hence, in embodiments of the invention, the cellulose material is obtainable by a method wherein step a1 ) comprises providing ensilaged parenchymal cell containing vegetable pulp, preferably by:

- providing fresh parenchymal cell containing vegetable pulp, preferably fresh sugar beet pulp;

- if necessary adjusting the dry matter content of the fresh vegetable pulp to reach a value within the range of 15-35 % (w/w);

- placing the vegetable pulp having a dry matter content of 15-35 % in storage under conditions favorable to the growth of lactic acid producing bacteria including covering the pulp with airtight material; and

- keeping the material under said conditions favorable to the growth of lactic acid bacteria until the pH of the vegetable pulp has reached a value of below 5, preferably a value within the range of 3.5-5. As is known by those of average skill in the art, common ensilaging practice results in the lactic acid fermentation as the required bacterial species are inherently present in the material.

Other examples of vegetable pulps that may be employed in accordance with the present invention include, but are not limited to, pulps obtained from chicory, beet root, turnip, carrot, potato, citrus, apple, grape, or tomato, preferably pulps obtained from chicory, beet root, turnip, carrot or potato. Such pulps are typically obtained as side-streams in conventional processing of these vegetable materials. In one embodiment the use of potato pulp obtained after starch extraction is envisaged. In another embodiment of the invention, the use of potato peels, such as obtained in steam peeling of potatoes, is envisaged. In some embodiments, the use of press pulp obtained in the production of fruit juices is envisaged.

In accordance with the invention, the (bio-)chemical treatment of step a2) results in the degradation and/or extraction of at least a part of the pectin and hemicelluloses present in the parenchymal cell containing vegetable pulp, typically to monosaccharides, disaccharides and/or oligosaccharides, typically containing three to ten covalently bound monosaccharides. However, as indicated above, the presence of at least some pectin, such as at least 0.5 wt.%, and some hemicellulose, such as 1-15 wt.%, is preferred. As will be understood by those skilled in the art, said pectin and hemicellulose remaining in the cellulose material can be non-degraded and/or partially degraded. Hence, step a2) typically comprises partial degradation and extraction of the pectin and hemicellulose, preferably to the extent that at least 0.5 wt.% of pectin and at least 1 wt.% of hemicellulose remain in the material. It is within the routine capabilities of those skilled in the art to determine the proper combinations of reaction conditions and time to accomplish this. In embodiments of the invention, the (bio-)chemical traetament, is or comprises chemical treatment, e.g. treatment with acid, alkali and/or oxidizing agent.

Preferably, the chemical treatment as mentioned in step a2) of the above mentioned method comprises:

- mixing the parenchymal cell containing vegetable pulp with alkaline metal hydroxide to a final concentration of 0.1-1.0 M, preferably 0.3-0.7 M; and

- heating the mixture of parenchymal cell containing vegetable pulp and alkaline metal hydroxide to a temperature within the range of 60-120 °C, e.g. 80-120 °C for a period of at least 10 minutes, preferably at least 20 minutes, more preferably at least 30 minutes.

The use of alkaline metal hydroxides, especially sodium hydroxide, in the above method, is advantageous to efficiently remove pectin, hemicelluloses and proteins from the cellulose. The alkaline metal hydroxide may be sodium hydroxide. The alkaline metal hydroxide may be potassium hydroxide. The alkaline metal hydroxide may be mixed with the parenchymal cell containing vegetable pulp to a concentration of at least 0.1 M, at least 0.2 M, at least 0.3 M, or at least 0.4 M. The alkaline metal hydroxide concentration preferably is at less than 0.9 M, less than 0.8 M, less than 0.7 M or less than 0.6 M. The use of relatively low temperatures in the present chemical process allows the pulp to be processed with the use of less energy and therefore at a lower cost than methods known in the art employing higher temperatures. In addition, use of low temperatures and pressures ensures that minimum cellulose nanofibers are produced. The pulp may be heated to at least 60°C, e.g. at least 80 °C. Preferably, the pulp is heated to at least 90°C. Preferably, the pulp is heated to less than 120°C, preferably less than 100°C. As will be appreciated by those skilled in the art, the use of higher temperatures, within the indicated ranges, will reduce the processing times and vice versa. It is a matter of routine optimization to find the proper set of conditions in a given situation. As mentioned above, the heating temperature is typically in the range of 60-120 °C, e.g. within the range of 80- 120°C for at least 10 minutes, preferably at least 20 minutes, more preferably at least 30 minutes. If the heating temperature is between 80-100°C, the heating time may be at least 60 minutes. Preferably, the process comprises heating the mixture to a temperature of 90-100 °C for 60-120 minutes, for example to a temperature of approximately 95 °C for 120 minutes. In another embodiment of the invention, the mixture is heated above 100°C, in which case the heating time can be considerably shorter. In a preferred embodiment of the present invention the process comprises heating the mixture to a temperature of 1 10-120°C for 10-50 minutes, preferably 10-30 minutes.

In an embodiment of the invention, at least a part of the pectin and hemicelluloses may be degraded by treatment of the vegetable pulp with suitable enzymes. Preferably, a combination of enzymes is used, although it may also be possible to enrich the enzyme preparation with one or more specific enzymes to get an optimum result. Generally an enzyme combination is used with a low cellulase activity relative to the pectinolytic and hemicellulolytic activity. The enzyme treatments are generally carried out under mild conditions, e.g. at pH 3.5-5 and at 35-50°C, typically for 16-48 hours, using an enzyme activity of e.g. 65.000-150.000 units / kg substrate (dry matter). It is within the routine capabilities of those skilled in the art to determine the proper combinations of parameters to accomplish the desired rate and extent of pectin and hemicellulose degradation.

In some embodiments it is beneficial to subject the mass resulting from step a2) to treatment with an acid, in particular sulphuric acid. This step typically is performed to dissolve and optionally remove various salts from the material. It was found that by applying this step, the material eventually obtained has improved visual appearance in that it is substantially more white. Hence, the treatment of step a2) may comprise the additional step of mixing the treated parenchymal cell containing pulp with an acid in an amount to lower the pH to below 4, preferably below 3, more preferably below 2. Typically, the process of this invention will only include one acid treatment step. In some embodiments, acid treatment of the plant pulp is performed and the process does not contain any further steps wherein the material is treated with a bleaching agent. In addition, the acid treatment of the plant pulp was found to allow for even milder alkaline treatment of the material in step a2) of the present process. In a preferred embodiment, said acid is sulphuric acid. The acid treatment may be applied prior to as well as after the alkaline treatment.

It will be understood that the chemically and/or enzymatically treated pulp may suitably be subjected to one or more washing steps after any of the chemical and/or enzymatic treatments, so as to wash out the acids, bases, salts, enzymes and/or degradation products. Washing can be accomplished simply by subjecting the pulp or slurry to mechanical dewatering treatments, using e.g. a filter press and taking up the 'retentate' in fresh (tap) water, an acid or base, as is suitable. As will be understood by those skilled in the art, the pulp can be dewatered quite easily at this stage of the process as it has not yet been activated. In preferred embodiments of the invention, after the treatment with the base and/or enzyme and, optionally, the acid, has been completed, the treated pulp obtained accordingly is subjected to washing and is taken up in a quantity of aqueous liquid, such as (tap) water, to obtain the aqueous slurry comprising a mixture of an aqueous liquid and (bio- )chemically treated cellulose material.

Subsequently, in step a3), the aqueous slurry is subjected to (generally known) treatments, typically involving subjecting the cellulose material to high mechanical or physical (shear) forces, that alter the morphology of the cellulose, typically through the partial, substantial or complete liberation of cellulose microfibrils from the cellulose fiber structure and/or the opening up of the cellulose fiber network structure, thereby significantly increasing the specific surface area thereof. As is known by those skilled in the art, similar changes in the morphology and/or functional properties of the cellulose material can be brought about using certain enzymatic procedures, known as HefCel treatment.

In some embodiments of the invention, the mechanical and/or physical treatment is applied to reduce the particle size of the cellulose material so as to yield a particulate material or cellulose fine material having a characteristic size distribution. When the distribution is measured with a laser light scattering particle size analyzer, such as the Malvern Mastersizer or another instrument of equal or better sensitivity, the diameter data is preferably reported as a volume distribution. Thus the reported median for a population of particles will be volume-weighted, with about one-half of the particles, on a volume basis, having diameters less than the median diameter for the population. Typically, the slurry is treated so as to obtain a particulate composition having a reported median major dimension (D[4,3]), within the range of 15-75 μιτι, as measured using laser diffraction particle size analysis. A suitable apparatus for determining this (and other) particle size characteristics is a Malvern Mastersizer 3000 obtainable from Malvern Instruments Ltd., Malvern UK, using a Hydro MV sample unit (for wet samples). In preferred embodiments of the invention, the slurry is treated so as to obtain a composition having a reported median major dimension within the range of 20-65 μιτι or 25-50 μιτι. Typically, the reported D90 is less than 120 μιτι, more preferably less than 1 10 μιτι, more preferably less than 100 μιτι. Typically the reported D10 is higher than 5 μιτι, more preferably higher than 10 μιτι, more preferably higher than 25 μιτι. In accordance with certain embodiments, the mechanical and/or physical treatment does not result in the complete or substantial unraveling to nanofibrils.

To accomplish the desired structure modification a high mechanical shear treatment is preferably applied. Examples of suitable techniques include high pressure homogenization, microfluidization and the like. Most preferred examples of high shear equipment for use in step a3) include friction grinders, such as the Masuko supermasscolloider; high pressure homogenizers, such as a Gaulin homogenizer, high shear mixers, such as the Silverson type FX; in line homogenizers, such as the Silverson or Supraton in line homogenizer; and microfluidizers. The use of this equipment in order to obtain the particle properties in accordance with some embodiments of this invention is a matter of routine for those skilled in the art. The methods described here above may be used alone or in combination to accomplish the desired structure modification.

The slurry undergoing such high mechanical shear treatments typically has a content of the

(bio-)chemically treated cellulose material, based on the total weight of the slurry, of less than 10 wt %. In embodiments of the invention, the content of the cellulose material, based on the total weight of the slurry, is at least 0.5 wt.%,at least 1.0 wt.%, at least 1.5 wt.%, at least 1.75 wt.%, or at least 2.0 wt.%. In embodiments of the invention, the content of the cellulose material, based on the total weight of the slurry, is less than 9.0 wt.%, less than 8.0 wt.%, less than 7.0 wt.%, less than 6.0 wt.%, less than 5.0 wt.%, less than 4.5 wt.%, less than 4 wt.%, less than 3.5 wt.%, less than 3 wt.%, or less than 2.5 wt.%.

In embodiments of the invention, certain additives may be added to the slurry before subjecting it to the mechanical and/or physical shear treatment of step a). A preferred example of such additive is a thickener, which may be added to the slurry, e.g. after completion of step a2) as defined above, at levels resulting in a ratio (w/w) of the cellulose material and the thickener of more than 90/10, preferably within the range of 93/7 to 99.5/0.5, 94/6 to 99/1 or 95/5 to 98/2. Suitable examples of such thickeners include carboxycelluloses, such as the carboxycellu loses as defined herein elsewhere, especially carboxymethylcellulose.

In preferred embodiments of the invention, the mechanical and/or physical treatment is performed using a high pressure homogenizer wherein the material is passed through the homogenizer operated at a pressure of 50-1000 bar, preferably at 70-750 bar or 100-500 bar. In embodiments of the invention, the slurry is passed through said apparatus a number of times. In such embodiments, the mechanical and/or physical treatment comprises 2, 3, 4, 5, 6, 7, 8, 9 or 10 passes of the slurry through said apparatus while operating at suitable pressures as defined here above. It will be apparent to those of average skill in the art that the two variables of operating pressure and number of passes are interrelated. For instance, suitable results will be achieved by subjecting the slurry to a single pass over the homogenizer operated at 500 bar as well as by subjecting the slurry to 6 passes over the homogenizer operated at 150 bar. It is within the routine capabilities of the person skilled in the art to make appropriate choices, the suitability of which can be verified by subjecting the homogenized slurry to particle size analysis in accordance with what is defined here above.

As indicated herein before, the high mechanical shear treatment of step a3) may be performed using other types of equipment and it will be within the skilled person's (routine) capabilities to determine operating conditions resulting in equivalent levels of mechanical shear.

In accordance with the invention, the mechanical and/or physical treatment of step a3) is followed by a step a4) wherein at least part of the water is removed. Preferably step a4) is a mechanical or non-thermal dewatering treatment. In one preferred embodiment of the invention step a4) comprises filtration, e.g. in a chamber filter press. The removal of water may aid in the removal of a substantial fraction of dissolved organic material as well as a fraction of unwanted dispersed organic matter, i.e. the fraction having a particle size well below the particle size range of the particulate cellulose material. Preferably, step a4) of the process does not involve or comprise a thermal drying or evaporation step

As will be understood by those skilled in the art, it is possible to incorporate multiple processing steps in order to achieve optimal results. For example, an embodiment is envisaged wherein the mechanical treatment of step a3) is followed by subjecting the mixture to microfiltration, dialysis or centrifuge decantation, or the like, followed by a step of pressing the composition.

In accordance with the invention, in step a4), the slurry obtained in step a3) is concentrated to a dry matter content of at least 7.5 wt.%, preferably at least 10 wt.% Embodiments are also envisaged wherein the mechanical and/or physical activation/fibrillation treatment is performed using refining equipment specifically designed to process slurries containing more than 10 wt.% or more than 20 wt.% of cellulose material, such as described in WO 2017/103329. This may improve the efficiency of the processing in various way. For instance, the concentrating step after the activation/fibrillation treatment may become superfluous. Hence, in an embodiment of the invention, step a) of the process defined herein comprises:

a1 ) providing a parenchymal cellulose containing plant pulp;

a3) subjecting the material resulting from step a2) to mechanical/physical activation/fibrillation treatment, while having a dry matter content of at least 10 wt.%, preferably at least 20 wt.%; and a4) optionally concentrating the material as obtained in step a3) to a dry matter content of at least 10 wt.% or at least 20 wt.%.

Addition of carboxycellulose - Step b) In step b) of the process described earlier, the slurry provided in step a) is blended with the carboxycellulose in the (relative) amounts specified herein elsewhere.

In embodiments of the invention, the carboxycellulose is added in the solid form, suitably as pure carboxycellulose, or dissolved in a suitable quantity of aqueous liquid, such as (tap) water. The latter can make the process of blending the cellulose material and the carboxycellulose more efficient. In embodiments of the invention, step b) comprises adding to the aqueous slurry provided in step a) an aqueous solution comprising dissolved therein the carboxycellulose, typically at a level of 1-10 wt.%, 2-7.5 wt.%, or 3-6 wt.%.

As will be understood by those skilled in the art, the addition of the carboxycellulose as an aqueous solution inherently reduces the (relative) amount of the cellulose material to some extent.

In embodiments of the invention, a homogeneous slurry of the carboxycellulose and the cellulose material is produced using any suitable industrial mixing or kneading system. Such systems can be continuous or batch-wise. Suitable continuous mixers can be single or double shafted and co- or counter current. An example of a suitable system is the continuous single shafted Extrudomix from Hosokawa, which is designed to mix solids and liquids. Suitable batch mixers can be horizontal or vertical mixing systems. Suitable industrial horizontal mixers have e.g. Z-shaped paddles or ploughshaped mixing elements. Preferred systems include intermeshing mixing elements that produce forced flow of the paste between the elements (e.g. horizontal Haake kneader). Industrial vertical mixers are commonly planetary mixers. A preferred system includes double planetary mixers or single planetary mixers with a counter current moving scraper, such as vertical mixer Tonnaer, or a system equipped with a mixing bowl turning around in opposite direction to the mixing element.

Thermal dewatering - Step c)

In certain embodiments of the invention a method as defined herein is provided wherein step b) is followed by a thermal drying treatment to produce a product in solid or powder form. In an embodiment of the invention a method as defined herein is provided wherein step c) comprises drying the blend to the target dry matter levels, as specified herein elsewhere.

Without wishing to be bound by any theory, the temperature at which the concentrate is dried is believed to affect the chemical, structural and/or functional properties of the formulation aid obtained. In accordance with the invention the temperature of the material during the drying step is typically kept below 120 °C. In an embodiment of the invention a method as defined herein is provided wherein step d) comprises a thermal drying treatment wherein the blend produced in step d) or e) is heated to a temperature within the range of 30-1 10 °C, more preferably within the range of 40-100 °C, more preferably within the range of 50-95 °C, more preferably within the range of 60-90 °C, most preferably within the range of 70-85 °C.

In certain embodiments of the invention a method as defined herein is provided wherein step c) comprises a thermal drying treatment wherein the blend is subjected to temperatures as defined here above. In certain embodiments of the invention a method as defined herein is provided wherein step c) comprises a thermal drying treatment wherein the blend is placed in a dryer which is operated at temperatures as defined here above. Typically, in accordance with the invention, the drying step is performed using industrial drying equipment known to the skilled person such as a rotary dryer, static oven, fluidized bed, conduction dryer, convection dryer, conveyer oven, belt dryer etc. Preferably a dryer is used that achieves heat transfer and/or moisture removal by a gentle thermal treatment, such as by convection utilizing warm or hot air. Hence, in one embodiment of the invention step c) comprises subjecting the blend to a drying step wherein the blend is placed in an environment with an air temperature of below 120 °C, preferably a temperature within the range of 30-1 10 °C, more preferably within the range of 40-100 °C, more preferably within the range of 50-95 °C, more preferably within the range of 60-90 °C, most preferably within the range of 70-85 °C. In one embodiment of the invention step c) comprises subjecting the blend to a drying step wherein the blend is contacted with air heated to the aforementioned temperatures.

In embodiments of the invention step c) comprises subjecting the blend produced in step b) to a drying step using a convection oven. In other embodiments of the invention step c) comprises subjecting said blend to a drying step using a belt dryer. In other embodiments of the invention step c) comprises subjecting said blend to a drying step using a flash dryer

As will be understood by those skilled in the art based on the present teachings, the time needed to achieve the target water level in step c) will depend, amongst others, on the water content of the concentrate before drying, on the exact nature of the material, on the temperature applied, etc. It is within the capabilities of those of average skill in the art to carry out the process taking account of these variables. In an embodiment of the invention, a method as defined herein is provided wherein step c) comprises a thermal drying treatment wherein the blend is subjected to heating under conditions and for a period of time sufficient to reach a water content as specified here above.

Milling or grinding - Step d)

In accordance with the invention, a powder composition as obtained in step c) is subjected to a mechanical treatment step, resulting in a product in the form of a free-flowing powder, having a target particle size and/or density characteristics. Preferably, the treatment primarily affects the macroscopic size of the particles and does not substantially affect the cellulose material's structure per se. In general, conventional milling or comminuting treatments performed to achieve the particle size and/or density characteristics as defined herein elsewhere will not usually result in such changes to the primary, secondary and/or tertiary structures characteristic of the cellulose component contained in the material.

Typically, in accordance with the invention, the process is performed using industrial particle size reduction techniques known to the skilled person. Preferred methods include grinding using stirring blades such as unidirectional rotary-, multiaxis rotary-, reciprocal inverse-, vertical motion-, rotary and vertical motion-, and duct line-system stirring blades, such as portable mixers, solid mixers and vertical motion-, and duct line-system stirring blades; screen system crushing; impact crushing; cage milling; hammer milling; rotary extrusion system grinding using kneaders; screen milling; etc. These methods may be used alone or in combination. Preferably the milling or comminuting method is cryogrinding or cryogene hammer milling. Typically, in accordance with the invention, the milling or comminuting process is controlled to yield particles of a specific size. In a specific embodiment of the invention, the milling or comminuting process is carried out such that certain target particle size specifications are reached, such as specific target D10, D50 and/or D90 values.

The particle size distribution may be influenced by performing an additional step to select particles by size, e.g. to remove large particles or dust/fines. Conventional sieving techniques may be applied in accordance with the invention, such as centrifugal sifting, gyratory sifting, vibrating sifting, ultrasonic sifting etc. In an embodiment of the invention, a method as defined herein is provided wherein step d) is followed by sieving.

In embodiments of the invention with the invention the milling or grinding step is performed using equipment operated in such a way that the temperature of the material stays below 150 °C, below 140 °C, below 130 °C, below 120 °C, below 1 10 °C, or below 100 °C.

There are also technological solutions for drying and grinding in one machine, such as by using flash drying equipment, e.g. of the types produced by Hosokawa, Jaeckering and Siccadania; or by using thin film agitated drying equipment, e.g. of the type produced by Technoforce. Hence, embodiments are also envisaged wherein steps c) and d) can be performed simultaneously, so as to produce a powder composition having the target specifications as defined above.

Product obtainable by the method

Another aspect of the present invention concerns products obtainable by the present invention.

Applications of the powder composition

The present invention concerns the use of the powder composition as defined in the foregoing and/or as obtainable by any of the methods described in the forgoing as a dispersable or redispersable composition. In particular the present invention provides the use of the powder composition as defined in the foregoing and/or as obtainable by any of the methods described in the forgoing to provide a structured fluid water based composition such as a (structured) suspension or dispersion or a hydrogel. The term "fluid water based composition" as used herein refers to water based compositions having fluid or flowable characteristics, such as a liquid or a paste. Fluid water based compositions encompass aqueous suspensions and dispersions. Gels, in accordance with the invention, are structured aqueous systems for which G'>G", as explained herein before.

The fluid water based composition and hydrogels of the invention have water as the main solvent. Fluid water based composition may further comprise other solvents.

The fluid water based composition or hydrogel comprising the powder composition according to the present invention is suitable in many applications or industry, in particular as an additive, e.g. as a dispersing agent, structuring agent, stabilizing agent or rheology modifying agent. Fluid water based compositions may comprise the powder composition in sufficient quantities to provide a concentration of the cellulose component ranging between 0.25 % (w/v) and 3 % (w/v), more preferably ranging between 0.5 % (w/v) and 2 % (w/v) or between 0.75 % (w/v) and 1.5 % (w/v) .

The powder composition according to the present invention is in particular suitable to be used in detergent formulations, for example dishwasher and laundry formulations; in personal care and cosmetic products, such as hair conditioners and hair styling products; in fabric care formulations, such as fabric softeners; in paint and coating formulations, such as for example water-born acrylic paint formulations; food and feed compositions, such as beverages, frozen products and cultured dairy; pesticide formulations; biomedical products, such as wound dressings; construction products, as for example in asphalt, concrete, mortar and spray plaster; adhesives; inks; de-icing fluids; fluids for the oil & gas industry, such drilling, fracking and completion fluids; paper and cardboard or non-woven products; pharmaceutical products.

Embodiments are also envisaged, wherein the powder composition of the present invention is used to improve mechanical strength, mechanical resistance and/or scratch resistance in ceramics, ceramic bodies, composites, and the like.

In another aspect, the invention provides uses of the powder compositions of the present invention in accordance with what has been discussed elsewhere. Hence, as will be understood by those skilled in the art, based on the present disclosure, specific embodiments of the invention relate to the use of a powder composition as defined herein, including a powder composition obtainable by the methods as defined herein, for modifying one or more rheological properties of a water-based formulation and/or as a structuring agent in a water-based formulation. In an embodiment of the invention uses are provided for conferring the rheological properties according to what is defined herein elsewhere (to characterize the powder composition per se.

In another aspect of the invention, methods are provided for producing an aqueous structured formulation, such as the formulations described here above, said process comprising adding the powder composition of the present invention. Such methods will further typically comprise steps to homogeneously blend the powder composition and an aqueous formulation. In some embodiments of the invention, such methods comprise the step of mixing with an industrial standard impeller like a marine propeller, hydrofoil or pitch blade which can be placed with top, side or bottom entry. The method preferably does not involve the use of high speed impellers like tooth saw blades, dissolvers, deflocculating paddles and/or the use of equipment exerting high shear treatment, using for instance rotor-rotor or rotor-stator mixers. In embodiments of the invention, the method does not involve the use of equipment exerting shear in excess of 1000 s^~\ in excess of 500 s^~\ or in excess of 250 s^~ or in excess of 100 s^~ .

In another aspect of the invention, methods are provided for improving one or more properties of an aqueous formulation, such as the formulations described here above, said process comprising incorporating into the formulation, the powder composition of the present invention.

Thus, the invention has been described by reference to certain embodiments discussed above. It will be recognized that these embodiments are susceptible to various modifications and alternative forms well known to those of skill in the art. Many modifications in addition to those described above may be made to the structures and techniques described herein without departing from the spirit and scope of the invention. Furthermore, for a proper understanding of this document and its claims, it is to be understood that the verb "to comprise" and its conjugations is used in its non- limiting sense to mean that items following the word are included, but items not specifically mentioned are not excluded. In addition, reference to an element by the indefinite article "a" or "an" does not exclude the possibility that more than one of the element is present, unless the context clearly requires that there be one and only one of the elements. The indefinite article "a" or "an" thus usually means "at least one". The term "consisting" wherever used herein also embraces "consisting substantially", but may optionally be limited to its strict meaning of "consisting entirely". Where upper and lower limits are quoted for a property, for example the Mw, then a range of values defined by a combination of any of the upper limits with any of the lower limits may also be implied. It should be appreciated that the various aspects and embodiments of the detailed description as disclosed herein are illustrative of the specific ways to make and use the invention and do not limit the scope of invention when taken into consideration with the claims and the detailed description. It will also be appreciated that features from different aspects and embodiments of the invention may be combined with features from any other aspects and embodiments of the invention.

The following examples are offered for illustrative purposes only, and are not intended to limit the scope of the present invention in any way.

Examples

Example 1: Preparation of compositions in accordance with the invention

Carboxymethylcellulose (CMC) (Akucell AF0305) was obtained from AkzoNobel. The cellulose component was prepared according to the method of example 1 1 of WO2014/142651 , except that high pressure homogenization treatment was done by passing the chemically treated slurry (at 2.3 wt.% DM) 4 times over the Gaulin High Pressure Homogenizer, operating at 150 bar. The cellulose component was provided as a 21 , 1 wt.% DM slurry/paste.

Batches of 1 kg with cellulose component to CMC ratios (w/w) of 70/30 and 30/70 as shown in the table below were prepared by first dissolving CMC in demineralized water by low shear mixing with a propeller mixer for 30 minutes and subsequently adding the cellulose component. The resulting composition is treated at high shear by a Silverson L4R with a square hole screen, operating at 8000 rpm for 30 minutes.

Batches consisting of only cellulose component or CMC were prepared in the manner described above but without addition of the second component. Every batch was split in 4 portions: 1. Before drying

2. Freeze drying (overnight)

3. Vacuum drying (40^°C; 50 mbar; 3 days)

4. Oven drying (80^°C, overnight) Drying was performed to reach a dry solids content of above 93 wt.%. The dry solids weight contents attained in practice were within the range of 93.4 and 98.5 wt.%. The 3 dried batches were grinded in an IKA A1 1 basic mill with a knife cutter installed, to yield free flowing powder compositions.

The powder/flakes were re-dispersed by mixing 200 ml of water and an appropriate amount of the powder in a 400 ml beaker having a 70 mm diameter (ex Duran) using a propeller stirrer equipped with three paddle blades each having a radius of 45 mm, for instance a R 1381 3-bladed propeller stirrer ex IKA (Stirrer 0: 45 mm Shaft 0: 8 mm Shaft length: 350 mm), placed 10 mm above the bottom surface and operated at 700 rpm for 120 minutes, at 25 °C. The concentration of cellulose material was set at 1 wt.% (resulting in CMC concentrations of 0,43 wt.% or 2,3 wt.%). Because of air incorporation during mixing the mixtures were stored during the night to de-aerate before the rheological behavior was determined.

The re-dispersability of the dried batches comprising CMC was good; they could be completely redispersed within 30-60 minutes to yield dispersions without visually distinguishable lumps.

The viscosity and yield stress were determined by rotational measurements, the storage and loss modulus by an oscillating amplitude sweep measurement. Measurements were performed at 20°C on an Anton Paar rheometer, Physica MCR301 , with a 50 mm plate-plate geometry, PP50, and a gap of 1 mm. The results are summarized in the following table.

differen geometry is used: cup-bob CC27, gap 0mm. Comparative Example

This experiment was done in order to assess the effect of the cellulose component on the properties (especially the re-dispersability) of the powder compositions. To this end, the cellulose component used in example 1 was subjected to additional (intense) high pressure homogenization treatment, before combining it with the carboxymethylcellulose and tested again before and after drying.

Carboxymethylcellulose (CMC) (Akucell AF0305) was obtained from AkzoNobel. Cellulose material was prepared in accordance with the steps of example 1 1 of WO2014/142651 , except that high pressure homogenization treatment was done by passing the chemically treated slurry (at 2.3 wt.% DM) 4 times over the Gaulin High Pressure Homogenizer, operating at 150 bar.

In a volume of 7 liters an aqueous slurry comprising 1 % by dry matter of the cellulose component was prepared by low shear mixing. This slurry was homogenized 16 times at 400 bar using a Gaullin Iab60 homogenizer. Samples were set aside at this point (referred to as "Batch 1 "). A quantity of 1 kg of the obtained homogenized composition was mixed with 4.2 g CMC by mixing it for 5 minutes using a Silverson L5M-A mixer at 10000 rpm. A sample was set aside at this point (referred to as "Batch 2"). The resulting composition was dried in a stainless steel dish in an oven at 80°C to a dry matter content of approximately 92.5%. The samples thus obtained are referred to as "Batch 3"). Finally, some of the samples taken directly after homogenization were also dried using the same method. The samples thus obtained are referred to as "Batch 4".

The dried product was re-dispersed as a 1 % cellulose material by mixing 200 ml of water and an appropriate amount of the powder in a 400 ml beaker having a 70 mm diameter (ex Duran) using a propeller stirrer equipped with three paddle blades each having a radius of 45 mm, for instance a R 1381 3-bladed propeller stirrer ex IKA (Stirrer 0: 45 mm Shaft 0: 8 mm Shaft length: 350 mm), placed 10 mm above the bottom surface and operated at 700 rpm for 120 minutes, at 25 °C. The concentration of cellulose material was set at 1 wt.%. Because of air incorporation during mixing batch was stored during the night to de-aerate before the rheological behavior was determined. Batch 4 could not de redispersed.

Rheology measurements were performed at 20°C on an Anton Paar rheometer, Physica MCR 301 , with a 50mm plate-plate geometry, PP50, and a gap of 1 mm. The results are summarized in the following table.

Batch Storage modulus (G') Yieldpoint Flowpoint (Pa)

(Pa) (Pa)

1 665 6.16 84.05

2 110 1.37 n.a.

3 70 0.75 n.a.

4 n.a. n.a. n.a. The material from Batch 2 and 3 was re-dispersable by the above described low shear mixing protocol. However, the rheological performance of Batch 3 had diminished significantly by the drying and re-dispersing of the composition (i.e. compared to the product of Batch 2 that had not been dried).

Claims

1. Powder composition comprising water more than 70 wt.% of dry matter, wherein the dry matter comprises a combination of a cellulose component, selected from activated/fibrillated plant or micro-organism derived cellulose materials, and a carboxycellulose, characterized in that the powder composition can be dispersed in water at a concentration of the cellulose component of 1 wt.% to form a homogeneous structured system having a storage modulus (C) of at least 100 Pa, and/or a yield point (YP) of at least 1 Pa, and/or a viscosity at 0.01s^-1 of at least 200 Pa.s, and in that the powder composition can be dispersed in water at a concentration of the cellulose component of 1 % (w/v) to form a homogeneous structured system without visually distinguishable solids or lumps by mixing, in a 400 ml beaker with a 70mm diameter ex Duran and at 25 °C, 200 ml of water with the corresponding amount of the powder using a R 1381 3- bladed Propeller stirrer ex IKA, placed 10 mm above the bottom surface, at 700 rpm for 120 minutes,.

2. Powder composition according to claim 1 , wherein the cellulose component and the carboxycellulose are present at a ratio within the range of 20/80 to 80/20, more preferably at a ratio within the range of 40/60 to 70/30.

3. Powder composition according to claim 1 or 2, wherein the cellulose component and the carboxycellulose constitute at least 80 wt.% of the dry solids weight of the powder composition.

4. Powder composition according to claim 1 , comprising less than 25 wt.% of water, preferably less than 20 wt.%, more preferably less than 15 wt.%.

5. Powder composition according to claim 1 , wherein the cellulose component is a microfibrillated cellulose (MFC).

6. Powder composition according to claim 1 , wherein the cellulose component is obtainable by (bio-)chemically extracting cellulose from plant tissue and subjecting it to mechanical/physical and/or enzymatic activation/fibrillation treatment.

7. Powder composition according to claim 6, wherein the treated parenchymal cellulose material contains by dry weight, at least 50 % cellulose, 0.5-10 % pectin and 1-15 % hemicellulose, and having a D[4,3] within the range of 25-75 μιτι, as measured by laser light diffractometry.

8. Powder composition according to any one of the preceding claims, wherein the powder composition is free flowing.

9. A powder of any one of the preceding claims, having a water activity (Aw) of below 0.6.

10. Powder composition according to any one of the preceding claims, wherein the carboxycellulose is carboxymethylcellulose.

1 1. Process for making a powder composition as defined in any one of claims 1 to 0, the process comprising the steps of:

a) providing an aqueous slurry comprising a mixture of an aqueous liquid and a cellulose component, selected from activated/fibrillated plant or micro-organism derived cellulose materials, said slurry having a dry matter content of at least 7.5 wt.%, preferably at least 10 wt.%, more preferably at least 20 wt.%;

b) dispersing a quantity of a carboxycellulose into the aqueous slurry provided in step a), c) drying the blend as obtained in step b) at a product temperature not exceeding 120 °C; and

12. Powder composition obtainable by the process as defined in claim 1 1.

13. Use of a powder composition as defined in any one of claims 1 to 10 and 12 for modifying one or more rheological properties of a water-based formulation and/or as a structuring agent in a water-based formulation.

14. Method of modifying the rheology of an aqueous formulation comprising the step of dispersing a powder as defined in any one of claims 1 to 10 and 12 in said formulation, wherein said method does not involve the use of equipment exerting shear in excess of 1000 s^~ .