BACKGROUND

Microfibrillated parenchymal cellulose can be produced at medium solids content for various applications such as binders, rheology modifiers, emulsifiers and composites. It is, however, obtained as a water suspension with high water content. High moisture content is problematic adding cost in transportation, storage and shelf-life of the product. Removal of water causes aggregation of fibrils and hornification, yielding a dramatic loss of the intended properties upon re-suspending the product.

So far, various drying methods have been proposed to facilitate resuspension of wood-based microfibrillated cellulose. Freeze-drying and spray-drying (Zepic et al. Holzforschung 2014 68 (6); Peng et al. Cellulose 2011 19 (1) 91-102; Voronova, et al. Materials Letters 2012 (68) 164-167), and additives, such as cationic surfactant (Eichhorn, J Mat Sci 2009 45 (1) 1-33), carboxymethyl cellulose (Butchosa and Zhou, Cellulose 2014 21 4349-4358), sodium polyacrylate and cationic polyacrylamide (Lavoine, et al. Carbohydr. Polym. 2012 90 (2) 735-764) have been shown to prevent hornification of fibrils to some extent. Combining freeze-drying and NaCl addition has been reported to completely recover the properties of cellulose microfibrils (Missoum et al. Biomacromol 2012 13 (12) 4118-4125). The above methods to remove water have limitations and are difficult to scale-up, and do not always prevent the agglomeration of the fibrils.

There are patents describing the use of wood-based microfibrillated cellulose dispersions to stabilized water non-dispersive materials, such as oils, beginning from 1980 (Turbak U.S. Pat. No. 4,378,381A) However, these dispersions rely on chemical surface modification of microfibrillated cellulose and the dispersions are of low solids content, typically few percents of the total weight of dispersions.

SUMMARY

The inventors have surprisingly found that a liquid activator facilitates resuspension of a de-hydrated fibrillated parenchymal cellulose product.

According to a first aspect is provided a composition comprising fibrillated parenchymal cellulose, at least one liquid activator, and optionally water.

According to a second aspect is provided a refined composition comprising the composition of the first aspect processed into a powder-like substance or granules having a Carr index value below 40, preferably below 16, most preferably below 10; or a Hausner ratio below 1.6, preferably below 1.25, most preferably below 1.1.

According to a third aspect is provided a dry product comprising the composition of any of the preceding aspect in a dry state.

According to fourth aspect is provided a re-activated composition obtainable by a method comprising

a. Mixing the dry product or the refined composition with water or an aqueous medium to obtain a mixture.

b. Hydrating the mixture, preferably up to 1 day, most preferably up to 20 minutes, to obtain a hydrated mixture.

c. Mixing the hydrated mixture, preferably using high shear mixing, until reactivated.

According to a fifth aspect is provided a use of the composition, the dry product or the re-activated composition of any preceding aspect for moulding or extruding.

According to a further aspect is provided a method of producing an object by extrusion or molding comprising using the composition of the preceding aspects, the refined composition of the preceding aspects, the re-activated composition of the preceding aspects or a mixture comprising fibrillated parenchymal cellulose and resin.

According to a sixth aspect is provided a product comprising the composition, the dry product, or the re-activated composition of any preceding aspect in a form having a maximum dimension of 50 mm, preferably 0.05-15 mm, most preferably 1-10 mm and a packaging density between 100 and 1500 kg/m3, preferably 300-800 kg/m3.

According to a seventh aspect is provided a method for producing the composition of the first aspect comprising:a. Adding a liquid activator to a composition comprising by weight 10-50% parenchymal cell cellulose, most preferably 15-30%; and up to 90% water; andb. Refining the parenchymal cell cellulose mixture into a fibrillated parenchymal cellulose mixture.

According to an eighth aspect is provided a method for producing the composition of the first aspect comprising:a. Adding a liquid activator to a composition comprising by weight 10-50% fibrillated parenchymal cellulose, most preferably 15-30%; and up to 90% water, to obtain a fibrillated parenchymal cellulose mixture.

According to a ninth aspect is provided a use of the composition, the dry product, or the re-activated composition of any preceding aspect as an additive or component for modifying one or more of: viscosity, mechanical properties, strength, stiffness, toughness, binding properties, suspension stability, gel insensitivity to temperature, material insensitivity to temperature, shear reversible gelation, yield stress, and liquid retention of the composition of matter.

Compositions whose rheological or mechanical properties may be modified in this manner include foods, feeds, pharmaceuticals, nutraceuticals, personal care products, fibres, composite materials, non-woven materials, biomedical applications, papers, boards, paints, coatings, inks, glues and construction compositions. More specifically, possible compositions include oral care products; creams or lotions for epidermal application, including moisturizing, night, anti-age, or sunscreen creams or lotions; food spreads, including reduced fat, low fat, or fat free food spreads (for example, mayonnaise); feed compositions; paper and board products; and drilling fluids.

