WO2014049207A1

WO2014049207A1 - Robust material, method of producing the same as well as uses thereof

Info

Publication number: WO2014049207A1
Application number: PCT/FI2013/050935
Authority: WO
Inventors: Saila SEPPO
Original assignee: Greenbutton Oy
Priority date: 2012-09-25
Filing date: 2013-09-25
Publication date: 2014-04-03

Abstract

A method of preparing a robust material. The method comprise mixing together nanocellulose and water by adding the water to nanocellulose in finely-divided form to form an aqueous composition. Then the water is removed from the composition to form a rigid material. The novel material is light and can easily be mechanically shaped by cutting and shearing. The material can be used in the manufacture of construction boards, ornamental surfaces and various other three dimensional articles.

Description

Robust material, method of producing the same as well as uses thereof

Field of Invention The invention relates to a method for preparing robust materials, to materials prepared by such a method and to the uses of the materials thus obtained.

Description of Related Art Materials which are "robust" are rigid or solid or stiff or they exhibit a combination of such properties. They can be produced from a large number of materials.

Thus, new materials like a fullerene or a carbon nanotube have a physically robust structure. A carbon nanotube can be used to grind powder particles of metal, polymer or ceramics into nanosized particles, WO2010090479. Mechanically robust, thick low- porosity alumina films have been used in industry for high-speed fabrication until new generation ordered alumina membranes were in market, WO2008014977. Ceramic materials have resulted in a robust mechanical attachment and more sophisticated ceramic materials include hybrid components, CA2762482, CA2762291. US2012128991 introduces a robust, two component adhesive for laminating flexible packaging material.

Building materials are conventionally made up of natural materials such as clay, rocks, cement, gypsum, lumber, bricks, sand, and wood, and synthetic products. Building materials are grouped for example use in carpentry, insulation, plumbing, and roofing work. Specific novel, man-made materials, which can be characterized as robust material, are also available

A fiber-reinforced building material in one embodiment incorporates purified cellulose fibers that are chemically treated with a dispersant to impart improved dispersibility to the fibers, WO0233164 (A2). Cementitious binder was selected from the group consisting of Portland cement, high alumina cement, lime, and high phosphate cement. It has been invented a carbon-based composite building wave absorption and heat preservation material. According to the production method, carbon-based wave absorbing agent, common silicate cement, expanded and vitrified small balls, re-dispersible latex powder, hydroxypropyl methyl cellulose, wood fiber, polypropylene fiber, surfactant, foam stabilizer, water reducing agent, coupling agent, water and the like are adopted; and the material is obtained by adopting the steps of stirring, pouring molding, curing and the like. The material can be used for pouring roofs and walls of buildings, so that aims of electromagnetic radiation protection and energy conservation of the buildings are fulfilled, CN102718451.

When a high-strength non-burned building decorative material has been produced, quartz sand is mainly used as a support skeleton; high-standard cement is used as a binder; a fixing agent and a promoter ensure the curing and hardening effect of products; methyl cellulose and ash calcium powder can assist the improvement of hardening strength; The device comprises a stirrer, a first conveyer belt, a mold, a second conveyer belt, a vibration platform, a third conveyer belt, a strickling machine, a fourth conveyer belt, a mechanical arm, a sealing chamber, a sand-blasting machine, and a cutting machine; raw materials are proportioned and mixed, molded in a resin mold, cured through vibration, naturally dried, demolded, and sandblasted; desired dimensions are set and the cutting is performed; a production process with the mechanical arm and a conveyer belt streamline is adopted; the produced product has a large density, high strength, and has the performance of heat resistance, corrosion resistance, crack resistance, and freeze resistance, CN 102745956. The production method seems quite complicated.

Although building materials has been developed recently, there is a lack for a light- weighted, strong, water-balanced, insulating, cheap, easy producing and most importantly sustainable material.

Not only three-dimensional structures of the above kind can be characterized as being "robust", there are also known decorative structures which are based on solid and rigid layers. Thus, decoration of walls has been common and, when the idea has been to resemble blocks of stone wet plaster was used to make it. Finishes that were either marbled or grained were frequently found on doors and woodwork. As overall wall decorations became more simple, the frieze often became the major decorative focus of the room. A pendant frieze, border and companion stripe were included in an antique wallpaper. Borders were used to create panels in frieze, wall or wainscot areas, as well as substitutes for friezes at the top of the wall. In rooms with box beam ceilings, borders were used to outline the individual ceiling panels. A ceramic tile appearance imitation soft wall surface pasting decorative material for base surfaces of external walls and overcomes the shortcomings that the conventional ceramic tiles easily drop due to a large dead load when used for decorating the wall surfaces. The decorative material consists of a surface layer and an interface layer combined with the surface layer, wherein the surface layer consists of china black, grey black jade, arabescato corchia, acrylic emulsion, film- forming aids and a cellulose ether aqueous solution; the interface layer consists of emulsion, hydroxyethyl cellulose, talcpowder and water. The manufacturing method comprises the following steps of uniformly mixing and stirring interface layer materials at normal temperature; painting an interfacial agent on a steel die base plate, adding netless cloth into the interfacial agent, increasing the strength and forming the interface layer; uniformly mixing and stirring surface layer materials at normal temperature; and injecting the surface layer mixed materials into a steel die, extruding to form a finished product. CN102704639 (A)

There has been developed a colored cellulose containing finely divided particles (0.05-10 mm), which are coated and/or dyed with a coloring agent in presence of a reactive binder comprising a polyfunctional and water-dispersible epoxy resin-amine binder, as a thermosetting or an elastomer layer, in physically and chemically durable form. The decorative product comprises the visible colored particles exhibiting a mutual spacing. DE 102011118507 Al

A decorative facing material comprises textile fibres, carboxymethyl cellulose and surface- active substances. The textile fibres used are fully aligned and smoothly extended polyester threads with the following ratio of components, % by mass: carboxymethyl cellulose - 4- 50, fully aligned and smoothly extended polyester threads - 50-95, surface-active substances greater than 0-3. This decorative facing material for finishing walls and ceilings, primarily for internal rooms. WO2011146037 (Al)

A decorative mortar comprises the following components in parts by weight: 1.5-2.5 parts of hydroxyethyl cellulose ether with viscosity of lOOOOOmpa.s, 80-100 parts of water, 140- 180 parts of pure acrylic emulsion, 12-15 parts of dodecyl ester, 16-19 parts of glycol, 7- 8.5 parts of sodium polyacrylate, 1.2-1.8 parts of methyl alkylol amine and 650-750 parts of ceramic particle. This weather-resistant decorative mortar takes a colorful ceramic particle as a filling material, can be blended to form various styles and shapes according to the size and color of the ceramic particle, has the characteristics of bright color, good weather-resistant property and same service life as that of a building and never fades, and can be widely applied to outer wall decorative finish projects of top-grade communities and luxury villas, cf. CN102491684 (A). To conclude the survey, it can finally be noted that a water-based artificial granite paint has been developed in the field of the architectural decoration of both inner and outer walls. This granite paint is made by compounding sheet silicate tackifier/cellulose protective colloid composite granulating system and applying granulation technique, cf. CN102719162 (A).

The painting process for CCA (cellulose fiber-cement sheet) boards comprises the following steps: processing materials, spraying fluorocarbon white primers, spraying water-texture intermediate paints, spraying aqueous multicolor paints and spraying fluorocarbon transparent finish coats. The painting process is especially used for painting outdoor CCA boards to achieve artificial granite and marble effects, cf. CN102744187 (A).

Although decorative materials has been developed recently, there is a lack for a light- weighted, ability for new decorative effects and small-curvature cambered surface, strong, water-balanced, insulating, clear borders of color concentrate, of bright color, good weather-resistant property, cheap, easy producing and most importantly sustainable material for indoors and outdoors.

There is a need to develop novel robust materials which have a broad field of application. For the purpose of the present invention, the term "robust", when used in relation to materials, stands for properties typically selected from "rigid", "solid", "stiff, "compact" or "having high internal coherence". The "robust" material may also exhibit combinations of such properties. Summary of the Invention

The present invention aims at providing novel methods of producing materials which can be used in any of the above applications, and also in other applications which will be discussed below.

It is an object of the present invention to provide a novel and inventive material and method therein so as to solve the problems presented by the prior art. The present invention is based on the concept of producing robust materials from a nanocellulose raw-material.

Cellulose (C₆Hi₀O5)_n is a polysaccharide consisting of a long-chain β-D-glucose molecule. Cellulose is not soluble in water or in oil. Wood contains 33 to 50 percent of cellulose. Cellulose is the most common organic compound on earth.

The term "nanocellulose" in the present context document includes, for example, products that are frequently called fine cellulose fibers, microfibrillated cellulose (MFC) fibers, cellulose nanofibers (NFC), microcellulose, micro crystalline cellulose and level-off DP (degree of polymerization) cellulose.

Nanocellulose has the same molecular formula as standard cellulose, but it differs in the characteristics. Nanocellulose can be obtained from wood, straw, sugar beet and potatoes. Nanocellulose comprises of nanocellulose fibrelles, which have a substantially greater length than width (aspect ratio of at least 100 or more, more preferably 1000 or more). The small crystal and/or particle size means large specific surface area, high strength and biodegradability. Nanocellulose manufacturing processes are, for example, illustrated in the following publications: WO2011128322, TW201030196, JP 2004204380, US 7381294, RU

2298562, CN 102182089, WO2011154600. Nanocellulose is used as an additive in renewable and biodegradable composites, where it strengthens the structure. Plaster and cement industries utilize also the high strength of the nanocellulose by using it as an additive, cf. for example WO0228795. In addition to the above, nanocellulose can be used, inter alia, to prevent the flow of oxygen between materials, as a flocculant and as a rheology modifier, and even in energy storage in modern forms of batteries. For example tunable oleophobicity have been obtained by structured porous aerogels produced from nanofibrillated cellulose. The aerogel was produced by freeze-drying method (cf. Aulin, Christian, Julia Netrval, Lars Wagberg and Tom Lindstrom, Soft Matter 2010, vol. 6, issue 14, p. 3298). Aerogels could be mechanically robust, but their production method needs several steps.

As mentioned above, "nanocellulose" also includes microcellulose: Microcellulose comprises of microcellulose fibrelles, which have a substantially greater length than width (aspect ratio of at least 100 or more, more preferably 1000 or more). The small crystal and/or particle size means large specific surface area, high strength and biodegradability. Microcellulose is used as an additive in renewable and biodegradable composites, where it strengthens the system. Plaster and cement industries utilize also the high strength of the microcellulose by using it as an additive, cf. for example WO0228795.

Within the context of the present invention is has surprisingly been found that robust materials can be produced from nanocellulose without any treatment with auxiliary agents, such as use of adhesives, glues or resins. The present material, which can be characterized as a "biomaterial" in the sense that it consists essentially of a material derived from a natural polysaccharide obtained from renewal sources, is produced easily by mixing two natural products (nanocellulose and water or an aqueous solution).

Based on the above, the present invention provides solid materials, which comprise or consist of a composition of nanocellulose and water, wherein the material is robust. The present invention also relates to a method for manufacturing a material, wherein the method comprises mixing water into composition of finely-divided nanocellulose to obtain a robust material. The present invention further relates to the use of said material in construction industry, in cement industry, in medicine, in traffic, in aeroplanes, in and with other materials etc.

More specifically, the present method is mainly characterized by what is stated in the characterizing part of claim 1.

Various specific materials are prepared by the methods described in the characterizing parts of claims 13 and 22.

Novel materials are obtained by any of these methods.

The novel uses are characterized by what is stated in the characterizing part of claims 30 to 32.

Considerable advantages and important applications are obtained by the invention.

The present invention provides for example a material, which is basically a composition of nanocellulose and water, wherein the material is a coherent, structural material.

In one aspect, the novel materials are used for coating of, or forming shells for, medical tablets, ferromagnetic materials, or other particles. They may contain optical or other fibers, cables or threads and they can be used for free-suspension structures, for example with threads. In water they will be wetted.

The robust materials can be used for producing beads or pearls or trinkets. Such articles are suitable for decorative purposes, for DIY applications for handicraft, hobbies etc. In view of the good mechanical properties, high internal coherence, the material can be

mechanically shaped and processed, for example by cutting and drilling. Openings and bores can be formed. The materials can be used for making dolls and toys. Various jingles, bells, horns and similar objects which produce sound can be embedded in the robust material, which then are formed into desired shape. It has been found that noise and sound easily penetrate the material.

The present invention also provides a method for sustainable production of a material for example a heat-insulating, strong building material. The method comprises mixing water into composition of finely-divided nanocellulose powder, pressing the composition into a building block mold.

The present invention also relates to the use of said material as wallboard, in construction industry, in cement industry, and in building industry. Nanocellulose is produced from wood and it is pH neutral, not poisonous, safe to produce to a building material, and after use the building material is easily decomposed in water. The produced building material is a sustainable product, which is produced by green chemistry principles. Optical or other fibers, cables or threads can be included inside of the materials. For the purpose of building material application, the present materials can, for example, be manufactured to a density of about 200-500 kg/m³, they can be wet like wool and dry afterwards, they insulate heat, they can be heated to 100 °C, they can support heavy loads with more than ten times of its own weight.

In the connection of the present invention it was surprisingly found that the novel materials can be cut into thin plates. It is possible to cut the material to plates also when a glue was added into the material. The building material can also be cut with a saw. Especially the present materials can be colored and modeled and used for decorative purposes.

It was also surprisingly found that the novel materials, which in some embodiments have an appearance like a jelly, can be cut into thin slices.

The present invention is according to the principles of green chemistry. It prevents the formation of waste. The present material breaks down in water solution into nanocellulose dispersion. All atoms used in the process incorporates into the final product. The production process possess no toxicity to human health and the environment. The produced material is benign for building uses. The used solvent is water. The production process is energy efficient, because low or moderate temperatures and pressures are used. Spent raw materials, nanocellulose and water, are renewable materials; the production process is straightforward.

The material has good weather-proofing properties and it can be used in frosty weather, during the whole year outdoors.

Description of Embodiments

For the purpose of the present invention, "robust" materials are solid materials which exhibit properties of internal cohesion and of modest or high strength properties along with at least a certain extent of impact resistance. As will be explained in more detail below, the present materials can be jelly-like but they can still be mechanically treated e.g. with shearing forces without decomposition of the structure. Rather, a common feature of the various materials of the present invention is that they can be shaped mechanically by cutting or drilling or punching or sawing or by other conventional mechanical working methods involving cutting or shearing action. As stated above, the term "nanocellulose raw-material" includes not only materials that traditionally are labeled "nanocellulose", but also fine cellulose fibers, micro fibrillated cellulose (MFC) fibers, cellulose nanofibers (NFC), microcellulose, micro crystalline cellulose and level-off DP (degree of polymerization) cellulose. The nanocellulose raw-material preferably meets one or several of the following criteria:

- it has a crystal size of less than one micron,

- a particle size of less than 100 micrometers, preferably less than 50 micrometers,

- it is provided in the form of a powder having a bulk density of less than 500 grams per liter, preferably less than 100 grams per liter, and

- the dryness of the nanocellulose is more than 90 % by weight.

The present materials typically are formed from aqueous slurries which contain at least 10 %, in particular at least 15 %, preferably at least 20 %, for example 20 to 85 % solid matter, based on the dry weight of the solid matter dispersed in the aqueous phase. Of the solid matter present in the slurry, at least 25 % by weight, in particular at least 50 %, preferably 50 to 100 % by weight consists of nanocellulose, as herein defined.

A method according to the present invention comprises the following steps:

- providing an aqueous composition formed by nanocellulose raw-material and water or an aqueous solution, wherein the aqueous composition is produced by adding water or aqueous solution to the nanocellulose raw-material until a predetermined consistency of more than 10 % by weight of solid matter in aqueous phase is obtained;

- shaping the aqueous composition into a desired form; and

- drying the aqueous composition to provide rigid, solid article having the desired shape.

The addition of water can take place at ambient temperature (about 20 to 30 °C) and pressure. It is possible to operate at higher or lower temperatures as long as water or the aqueous solution or dispersion is in liquid form. To enhance absorption of water into the material, addition can be accompanied by agitation of the components.

In an advantageous embodiment, water or an aqueous solution is added to dry

nanocellulose material, for example a dry powder. The amount of water added is at least essentially equal to the amount of water needed for thoroughly wetting the material, i.e. the amount of water corresponds to the amount of water which the material is capable of taking up. In another embodiment, water or an aqueous solution is added to moist or wet

nanocellulose material. Also in this embodiment, the amount of water added is sufficient for thoroughly wetting the material.

In a third embodiment, water or an aqueous solution is added in surplus with respect to the amount sufficient for thoroughly wetting the nanocellulose material. Thus, an aqueous slurry is formed. The slurry may be dispersed to obtain a homogeneous slurry.

Depending on the aimed use of the aqueous composition, the concentration of water or an aqueous solution varies. In general, the water content is 90 % or less, preferably about 50 to 85 %, calculated from total weight of the composition.

In a first embodiment, the nanocellulose content is 15 to 45 % by weight, typically 20 to 42 % of the total weight of the composition. This kind of material is suitable for forming various three-dimensional objects, for both decorative purposes and for building, construction and packaging purposes.

In a second embodiment, the nanocellulose content is about 15 to 30 % by weight of the total weight of the composition. This material is suitable for moulding and can be used for producing various kinds of construction material, isolating and structural boards etc.

In a third embodiment, the nanocellulose content is somewhat higher and the composition is produced from a non-dried nanocellulose material. The obtained aqueous composition has a nanocellulose content of about 25 to 50 % by weight of the total weight of the composition, and is suitable for composition which are coated on the surfaces of various substrates.

In a fourth embodiment, the composition is used for producing a substrate for growing of flowers and plants, and the composition contains about 20-30 % nanocellulose calculated from the total weight of the composition. The fourth embodiment is also particularly carried out using non-dried nanocellulose.

In the present context, the term "dry" when used in conjunction with the raw-material stands for a moisture content of less than 10 %, in particular less than 7.5 %,

advantageously less than 5 %, suitably less than 2.5 % and preferably less than 1 % by total weight of the raw-material. Typically, commercial, dry nanocellulose raw-materials - as defined above - contain about 0.1 up to 10 % by weight of moisture. By contrast, the non-dried raw-materials contain more than 10 % by weight of moisture, typically about 12.5 up to 50 % by weight, calculated from the total weight of the raw- material. As pointed out above, pure water or an aqueous solution can be used for wetting of the nanocellulose material. The term "aqueous solution" includes water-based solutions which may contain dissolved or even dispersed components. Such dissolved or dispersed components can be solid or liquid or gaseous at ambient temperature and pressure.

In any of the above embodiments, the material can be left to settle for at least 5 hours, more preferably for at least 10 hours, most preferably for at least 24 hours up to 148 hours, after the addition of water. The aqueous compositions are dried in order to lower their water content and in order to solidify the material. Typically the material is dried in air. Heat can be supplied to enhance evaporation of water. A typical drying temperature ranges from 30 to 150 °C, in particular about 40 to 120 °C. Evaporation can be carried out at normal pressure or for example at an absolute pressure of 0.01 to 0.9 bar. As will be discussed more closely in connection with a specific embodiment, it is generally possible to remove at least a part of the water sorbed by the material mechanically, by suction or by gravitation.

Generally, the solid products obtained upon drying have a density of 50-800 kilograms per cubic meter, and they contain less than about 10 % by weight of water, the remainder being formed by nanocellulose (as defined above) along with a optional auxiliary agents up to about 20 % by weight, preferably the latter make up 10 % by weight or less.

The robust material generally has a moisture content of less than 15 % by weight, preferably less than 10 % by weight, in particular less than 7.5 % by weight, and typically at least 0.1 % by weight in particular at least 0.5 % by weight, after the drying.

The novel material and the method of producing the same find many interesting applications. It has surprisingly been found that building material (plates or blocks) can be produced basically from nanocellulose and water. The bio material (in the sense defined above) is produced straightforward by mixing two natural products. Preferably, the method of sustainably producing sustainable building materials comprises the steps of mixing nanocellulose powder or undried microcrystalline cellulose together with water to form a mixture, and transferring the mixture into a mould, and producing a block or plate by drying of the mixture in the mould.

The material can be pressed before transferring it into the mould, or it can be pressed in the mould.

The composition used for moulding preferably contains some free water, in particular the amount of free water is at least 5 % of the water bound to the nanocellulose raw-material.

Although the material used for the moulding can be comprised of only water and nanocellulose, it is also possible to include some other components such as binders (glues) as additive materials

By the afore-described steps, solid products are obtained which upon drying have a density of 50-800, more preferably 100 to 700, in particular 250-650 kilograms per cubic meter

The material is typically capable of supporting heavy loads; in particular the material is capable of supporting loads of more than ten times their weight.

One interesting property of the present building and constructional materials is that they are capable of being colored. In addition or alternatively, they are capable of

accommodating internally (inside their bulk) three-dimensional objects (blocks or plates, for example) cables or other substances or materials.

Building boards and panels can be produced from the present materials.

In a first embodiment, the building parts are moulded by transferring a composition of suitable consistency into a mould - which corresponds to the desired shape of the building part - in which it is rigidified, typically by removing water. Removal of water can be carried out by mechanically, by suction or by gravitation. For this purpose, a mould with permeable walls is preferably used. The predried object can then be dried to final moisture content by evaporating the remaining water or humidity at a temperature of about 30 to 150 °C.

In another embodiment, the building boards are produced by cutting or sawing blocks of material e.g. formed by moulding as explained in conjunction with the previous embodiment. Typically, the blocks need not be dried to final moisture content before the building boards or panels are cut or sawn from them.

Building boards or panels formed from the present materials are very light-weight and they are suitable for replacing various insulation material since they have a capability of absorbing moisture and distributing it on a large area. This will reduce the risk of mould- formation.

The material can be produced as blocks or other kinds of blank which can then be cut into suitable objects such as plates, e.g. plates for use as wallboards.

Based on the above, the present solid materials can be used as building materials, in other materials, in cement, as strengthener, as composite material, as pillars, in houses, in cottages, in buildings, in bridges, in towers, in floors, in roofs, in ceilings, and in walls.

Boards and other self-supporting layers and coatings can also be used as filters, e.g. instead of conventional filtering boards. In one experiment, a juice produced from berries was filtered through a board of the above kind, and the filtrate was clear and all solid matter was retained on the board. Although conventionally, filters are easily miscoloured by berries and parts thereof, in the instant case, washing of the board with water was facile and it was ready for new use immediately after washing.

As discussed above, the present materials can be colored and modeled. In an embodiment for producing sustainable decorative material, microcellulose powder or undried microcrystalline cellulose is mixed together with water, and the mixture is pressed on the surface of a substrate, and processed into a decorative material when drying. By the afore-described steps, solid products are obtained which upon drying have a density of 50-800 kilograms per cubic meter. In particular, products can be produced which have a density of 100 to 700 kg/m³, for example 250 to 650 kg/m³. As a special application, it may be mentioned that the present materials when applied for building purposes can be used for creating underwater constructions, e.g. in aquariums. On one hand the material has good water-resistance. But on the other hand it can also be decomposed in water to yield nanocellulose, including microcellulose, particles. Thus, the building material can be decomposed in water after use and recycled for new use.

The material can for example be manually moulded when disposed on the surface of the substrate. The material can also be processed by pressing to produce pictures, reflect image, pattern, letters, numbers, or rosettes, produce decorative wall friezes and pointing. The decorative layer can be produced on a wallboard. The decorative material can also be produced on both indoor and outdoor walls, on ceiling, in/on furniture, as balancing humidity in room, as decoration, as wall lawn, and as insulation.

It has excellent acoustic properties. There is a great need for suitable, non-toxic acoustic materials.

Thus, the present materials, when shaped into layers of various thicknesses (typically 1 to 500 mm, in particular about 5 to 100 mm), will not only form a decorative surface, but in contrast to conventional plaster of Paris -type surfaces, they will also provide improved acoustic properties, and sound-proofing and balancing of moisture content in living quarters. It is suitable for use indoors and outdoors.

The material can be easily recycled and pulped in water.

As with the building materials application, the mixture may contain other materials for example binders (glues) as additive materials either inside the material

or between the material and the surface. For decorative purposes it is especially interesting that the material can be coloured with paints, such as acrylic pastes or paints, or with some other coloring agents.

The invention is explained in greater detail below by means of embodiment examples illustrating the preparation of a three set of rigid materials containing nanocellulose and by referreing to the results obtained with these materials.

This invention has been made by using household and kitchen items, devices and materials. That gives a good opportunity to use this invention very widely.

Finally, one very specific use of the present materials is as a substrate for plants and flowers. It can be used in pots and be combined with various sources of fertilizers and nutrients including solid and liquid. Examples

Materials

Microcellulose was employed both in dried form and as non-dried (having a dry matter content of about 30 to 50 % by weight). The non-dried form was an experimental grade obtained from the Aalto University in Espoo, Finland. In addition also two other grades, M50 and M90, J. RETTENMAIER & SOHNE GMBH+CO.KG, Germany, were employed.

The nanocellulose powder obtained from Aalto exhibited (in dry form) a weight per volume of less than 500 grams per liter, for example less than 150 grams per liter. The mean agglomerate size of the nanocellulose powder was 20-40 micrometer, measured by laser diffraction method. According to the electron microscope pictures the crystal size was about 100-300 nm. In the examples of the B series microcellulose produced according to published patent application WO2011154601 Al was used. Example Al

A material was prepared by mixing water to nanocellulose powder until the nanocellulose was totally wetted. The material looked like a jelly, but it could be cut into thin slices like bread. The surface of the slices looked similar as it were a spongy cake. The material was produced to a ball. It was easy to model it. Then it was left to settle for a couple of days. The material was put in a bowl and water was added. The material was taken out from the water. It was wetted by kept its form and shape. When placed in water, a ball prepared from the material retained its shape. Although it was wetted when immersed in water, the water absorbed could easily be removed when the material was lifted from the water and the material exhibited the same form as before immersion and regained its mechanical properties (it was "robust") when it had dried. Example A2

A material was prepared by mixing water to nanocellulose powder until the nanocellulose was totally moistened. The material was divided in three parts and each part was colored with watercolors. The material was in yellow, red, and blue parts. The colored material was pressed gently and produced to balls. The balls looked and felt like marshmallow. And it was easy to format them.

The balls were left to dry overnight. Then very lightweight balls were dropped on the floor, but they did not decompose. The material was found to be a robust structure.

Example A3

The material was prepared as in Example A2, but all the material was colored with a red watercolor. The material was produced to balls, but inside of the balls was added iron powder. The balls were left to dry overnight on the table. The balls and small household magnets were stuck together.

All the balls were found magnetic. The iron is unevenly distributed within the material. Example A4 The material was prepared as in Example A2, but all the material was colored with a yellow watercolor. The material was produced to balls, but inside of the balls was added threads. The balls were left to dry overnight.

All the balls were set to hang by a thread for one week's time.

Example A5

The material was prepared as in Example Al . Then it was produced to one bar. The material was cut into thin slices and after that all the slices were cut rectangularly. Small pieces of the material was arranged symmetrically on the plate.

All pieces of the material were nicely apart.

Example A7

A material was prepared by mixing acetic acid to nanocellulose powder until the nanocellulose was totally moistened. The material was colored with a blue watercolor. The material was pressed gently and produced to balls. The balls looked tight, but the blue color was vanished.

The balls were left to dry overnight. Then the very lightweight balls were dropped on the floor, but they did not decompose. The material was found to be a robust structure.

Example A8 (comparative)

A material was prepared by mixing water to potato flour until the flour was totally moistened. No bars neither balls could be produced. It was only produced a gel. Example A9

A mixture of nanocellulose and water was produced as explained above and divided in two parts, one was dyed with red and the other with blue foodcolouring (Dr. Oetker Sverige Ab). Firm balls were manually formed from the compositions. They were robust and held the colour well. Small balls can be used, for example as decoration of cakes and cream cakes. They are edible and can also be safely used for childrens toys shaped as various objects. It is also possible to dye the material with textile colouring. Example A10

Balls prepared according to Example Al were dropped into an aquarium. At first they floated on the surface, but after a while, when they had become throughout soaked with water they were deposited on the bottom of the tank. Molluscs ate of the balls by carving out the internal parts of them, leaving the shell parts largely intact, so that the balls were given a cuplike shape. The cups were taken up from the water, and the structure left was found to be strong and durable..

Example Al l

According to the example two sets of balls were used, one with hot water and the other with cold water. The balls were dried to absolute dryness and then balls from both groups were placed in water simultaneously.

The balls of both groups were soaked with water and deposited on the bottom of the tank. No decomposition could be seen. The balls were recoved and their mass was weighed. It was found that the mass had grown three-folded due to the absorbed water.

Some balls were crushed to form a dispersion from which new balls were produced. The balls were before forming filled with fish food in flakes. The balls were dried but not to absolute dryness. The balls were placed in an aquarium wherein the once again submerged to the bottom. The balls containing fish food had crack-formation in the shell and fishes became interested in the fish food thus exposed. The fish ate all of the food rapidly. Thus, it is suggested based on the tests that the present material is suitable as a carrier of encasing for food, which can be used for feed of fish.

Example Al l

A material was produced according to Example Al and it was dyed with red acrylic colorant which was added to the composition. By using an non-dried composition of this kind, wooden balls were coated. The balls were dried and it could be found that the materials are very suitable for coating of wooden surfaces.

Example Bl A material was produced by mixing water to undried nanocellulose slurry until the nanocellulose slurry included free water. The material looked like a jelly, and it was placed in a rectangular plastic mold. Then it was left to settle for a couple of days or baked in oven at 75 °C for two hours. Before completely drying, the material was poured from the mold and let dry on a plate to the density of 430 kg/m³. The weight of the block was 575 grams. It was compact and it was tested to support weight of at least hundred kilograms. One particle with 6 grams supported an object of at least 70 kilograms. Example B2

A material was prepared by mixing water to undried nanocellulose slurry until the nanocellulose slurry included free water. The material was divided in three parts and each part was colored. The material was colored in yellow with acrylic painting paste, red with commercial paint for outdoors use, and blue with commercial paint for indoors use. The colored material was pressed into rectangular plastics molds. The material was poured from the molds on a plate. The material was dried at 75 °C for some hours. The weight of the material blocks were 50-75 grams and the blocks were tested to support an object of at least 100 kilograms.

Water was dispersed on the blocks. All other than the red one absorbed the water and dried afterwards. The red one was hydrophobic.

Example B3

A material was produced by mixing water to nanocellulose powder until the nanocellulose was totally wetted. The material looked like a jelly, and it was placed in a rectangular plastic mold. Then it was left to settle for a couple of days or baked in oven at 75 °C for two hours.

Before completely drying the material was poured from the mold and let air dry to the density o f 250 kg/m³.

The weight of the block was 50 grams. It was compact and it was tested to support an object of at least hundred kilograms. The article can be painted as desired.

Example B4

The material was produced as in Example Bl, but all the material was mixed together with commercial glue. The material was pressed into a rectangular, one liter volume container mold. The material was taken out of the mold and dried on a plate until its density was 480 kg/m³.

The weight of the block was 350 grams. It was compact and it was tested to support an object of at least hundred kilograms. Example B5

The material was produced as in Example B3. The material was taken out of the rectangular 0.5 liter volume container mold. It was cut into thin plates and the plates were dried separately.

More plates were produced with the same method and a rectangular house was built. The walls, ceiling and roof were of the produced plates. Example B6

The material was produced as in Example B5, but the wet material was mixed together with commercial glue. The material was taken out of the 0.5 liter volume rectangular container mold. It was cut into thin plates and the plates were dried separately.

One plate (one wall) weighted about 20 grams and it was one centimeter thick, and it was tested to support an object of at least hundred kilograms.

Example B7 As in Example B6 a rectangular house with walls of the produced material was built. Its floor was also of the produced material. A plastic covered ice cube was placed inside and the house was tightly covered with produced material. Similar plastic covered ice cubes were placed all around the room. It was discovered that the ice cube in the built house melt significantly slower rate than the other ice cubes.

Example B8

The material was produced as in Example B4 and the solid rectangular material was put in fridge for one day. After that the material behaved as before the freezing process.

Example B9 (comparative)

A material was produced by mixing water to oat fibres until the powder was totally moistened. The slurry was put in the molds, but no material was produced. Example BIO (comparative)

10 grams of nanocellulose powder was mixed with a blender together with 90 grams of cold water. A nanocellulose gel was produced. It was left to dry a couple of days and at last same kind of building material was produced as in Example Bl .

Example CI A material was produced by mixing water to undried microcellulose slurry until the microcellulose slurry was easy to mold by hand. The material was pressed on wood plank surface and after drying on the surface the material seemed decorative, like ornate marble.

Example C2

A material was prepared by mixing water to undried microcellulose slurry until the microcellulose slurry was easy to mold by hand. The material was divided in three parts and each part was colored. The material was colored in yellow with acrylic painting paste (Winsor&Newton, Galeria Acrylic), red with commercial paint for outdoors use (Tikkurila Oyj, Pika-Teho), and blue with commercial paint for indoors use (Tikkurila Oyj, Joker). Each colored material was pressed unevenly on wood plank surface so that rosettes were produced on surface.

The surface of the red colored material was hydrophobic, because when spraying water on dried surface, the surface excluded water molecules off from the surface. This means the red decorative material is suitable for outdoor applications.

The other decorative materials absorbed the sprayed water in the material and divided it evenly in the material. Afterwards the material dried. This means the material for example on frieze is superior for humidity balance in the room. Example C3

A material was produced like in Example CI . The material was pressed on wood plank surface. Grass seeds were placed on the surface of the material and the material was wetted. The grass grew on the surface and it was wetted from time to time.

The material with lawn could be used on outdoor walls.

Example C4

The material was produced as in Example CI, but the wet material was mixed together with commercial glue (Akzo Nobel Deco International AB, Eri Keeper). The material was pressed on and against the surface of a wood plank. After it had dried it looked like ornate marble.

Example C5

The material was produced as in Example CI . The plank surface was treated with a water-based glue and the material was pressed after that on the surface. After drying the material was tightly attached on the surface. Afterwards the decorative material was painted to yellow with commercial water-based paint

Example C6 The material was produced as in example one and the wet material was divided in five parts and each part was colored differently by acrylic painting paste. The materials were pressed on the wood plank surface so that a colorful flower was produced on the surface. All colors had clear borders. Example C7

The material was produced as in Example CI and the wet material was colored with blue commercial indoor paint. The material was pressed on the surface of the wood plank so that the thickness of the material layers on the surface differed greatly from each other. The material surface was remarkably three dimensional.

Example C8

The material was produced as in Example CI and the wet material was colored with red commercial outdoor paint. The material was pressed on the surface of the wood plank so that decorative curved patterns were produced. The plank was kept for five days outdoors (in Finland) at a temperature of minus fifteen degrees. Then it was taken indoors and it was similar as before the freezing temperature.

Example C9

The material was produced as in Example CI and the wet material was colored with commercial blue indoor paint. The material was pressed on the surface of a plank with no adhesion to the material. The decorative material dried on the surface. It was removed from the surface and put on the wall with help of a glue.

Example CIO (comparative)

A material was produced by mixing water to oat fibres until the powder was totally moistened. The slurry was pressed on the surface of wood plank. No decorative appearance was seen. Example CI 1

The material of CI was removed from the surface and dispersed in water. It

decomposed completely after some hours. The following clauses represent embodiments:

1. A method for preparing robust material, wherein nanocellulose powder is mixed together with an inorganic liquid. 2. A method as defined in clause 1, wherein the inorganic liquid is an aqueous solution.

3. A method as defined in clause 2, wherein the inorganic liquid is water.

4. A method as defined in any of the preceding clauses, wherein nanocellulose is 60% moistened, more preferably 80% moistened and most preferably 100 % moistened. 5. A method as defined in any of the preceding clauses, wherein the material is left to settle 5 hours, more preferably 10 hours, most preferably 24 hours or more.

6. A method as defined in preceding clauses, wherein the material was gently pressed and produced to a ball or a bar.

7. A method as defined in preceding clauses, wherein the material was colored and/or inside the balls was hidden iron powder or other substance or

material.

8. A method as defined in any of the preceding clauses, wherein the nanocellulose has crystal size less than one micron and particle size less than 50 micrometers. The bulk density of the powder is less than 500 grams per liter, preferably less than 100 grams per liter. The dryness of the nanocellulose is more than 90%.

9. Robust material, which contains a mixture of the nanocellulose

and inorganic liquid, the more preferably aquatic liquid, most preferably water.

10. Use of the material prepared as in any of clauses 1 to 8 as plasticine, in decorations, in art work, in fertilizers, in building materials, in other materials, in cement, in medicine industry, in paints, in cosmetics, as strengthener, as

composite material

Claims

Claims:

1. A method of preparing a robust material comprising the steps of

- mixing together a nanocellulose raw-material and water or an aqueous solution by adding the water or aqueous solution to the nanocellulose raw-material present in finely-divided form to produce an aqueous composition, and

- removing water from the composition to form a rigid material.

2. The method according to claim 1, wherein water or an aqueous solution is added such that at least 60 %, preferably at least 80 %, in particular 100 % by weight of the nanocellulose is moistened.

3. The method according to claim 1 or 2, wherein the nanocellulose raw-material is wetted with water or an aqueous solution which is added such that there is an excess of 0 to 100 % water calculated from the weight of water needed to fully moisten the nanocellulose.

4. The method according to any of the preceding claims, wherein the material is left to settle 5 hours, more preferably 10 hours, most preferably 24 hours or more, after the addition of water or aqueous solution.

5. The method according to any of the preceding claims, wherein the nanocellulose raw- material is provided in the form of a dry powder or as a moist powder.

6. The method according to any of the preceding claims, wherein the material is pressed and shaped to produce a three-dimensional object, such as a planar, cylindrical or spherical structure or an object having at least one planar, cylindrical or spherical surface.

7. The method according to any of the preceding claims, wherein water is removed from the composition by one or several of the following steps:

- mechanically;

- by application of suction; and

- by thermally drying the composition involving evaporating water at a temperature of 30 to 150 °C, for example 40 to 125 °C, in particular 50 to 110 °C.

8. The method according to claim 7, wherein the evaporation of water is carried out at normal pressure or at an absolute pressure of 0.01 to 0.9 bar.

9. The method according to any of claims 1 to 8, wherein the robust material has a moisture content of less than 15 % by weight, preferably less than 10 % by weight, in particular less than 7.5 % by weight.

10. The method according to any of the preceding claims, wherein the composition is colored and/or mixed with solid particles.

11. The method according to claim 9, wherein mineral or metal powders are mixed with the composition before it is being shaped into a three-dimensional object, such as spherical objects.

12. The method according to any of the preceding claims, wherein the nanocellulose raw- material meets one or several of the following criteria:

- it has a crystal size of less than one micron,

- the dryness of the nanocellulose is more than 90 % by weight.

13. The method according to any of the preceding claims for producing sustainable building material, wherein nanocellulose powder or undried microcrystalline cellulose is mixed together with water, and the mixture is transferred into a mold, and produced to material blocks or plates or similar solid material upon drying.

14. The method according to claim 13, wherein the mixture contains free water.

15. The method according to claim 13 or 14, wherein the mixture contains additives, such as binders or glues.

16. The method according to any of claim 13 to 15, wherein the solid material is dried to the density of 50-800, more preferably 100-700, in particular 250-650 kilograms per cubic meter

17. The method according to any of claims 13 to 16, wherein the material is capable of supporting loads having a weight of at least 1 to 50, preferably 5 to 20 times its own weight.

18. The method according to any of claims 13 to 17, wherein the material is compressed and moulded to produce a solid material, said steps of compressing and moulding being carried out simultaneously or in consecutive order.

19. The method according to any of claims 13 to 18, wherein the material is colored.

20. The method according to any of claims 13 to 19, wherein cables, pipes or other solid objects are incorporated into the solid material, preferably in such a way that they are non- visible from the outside of the solid material.

21. The method according to any of claims 1 to 20, wherein solid material is subjected to mechanical processing by cutting or shearing forces, for example a solid material in the shape of a block is cut into plates which can be used, for example as wallboards.

22. A method according to any of claims 1 to 12 for producing sustainable decorative material, wherein microcellulose powder or undried microcrystalline cellulose is mixed together with water or an aqueous solution, and the wet mixture is pressed onto a surface to produce a coating layer on said surface, and said coating layer is dried to produce a decorative material.

23. The method according to claim 22, wherein the coating layer is mechanically shaped before or during drying to give the material its preselected shape or form.

24. The method according to claim 23, wherein the coating layer is pressed to produce pictures, reflect image, pattern, letters, numbers, or rosettes, decorative wall friezes, stucco or ornamental plasterwork.

25. The method according to any of claims 22 to 24, comprising the steps of incorporating additive materials into the mixture, providing additive materials on the surface of the coating layer, or a combination thereof.

26. The method according to any of claims 22 to 25, comprising the steps of

- colouring the wet mixture is colored with a colouring agent, for example acrylic paste or paint or a combination thereof;

- painting the coating layer is painted, before, during or after drying; or

- performing a combination thereof.

27. The method according to any of the preceding claims, wherein the surface is the surface of a substrate, such as a planar, cylindrical or spherical three-dimensional object, preferably a planar structural or decorative structure, such as a wall or a wallboard.

28. The method according to any of the preceding claims, wherein the nanocellulose raw- material is selected from the group of nanocellulose, fine cellulose fibers, micro fibrillated cellulose fibers (MFC), cellulose nanofibers (NFC), microcellulose, micro crystalline cellulose and level-off DP (degree of polymerization) cellulose and combinations thereof.

29. A material produced by a method according to any of claims 1 to 28.

30. Use of a material prepared according to a method according to any of claims 1 to 12 or 27 or 28 as plasticine, in decorations, in art work, in fertilizers, in building materials, in other materials, in cement, in medicine industry, in paints, in cosmetics, as strengthener, as composite material

31. Use of a material prepared according to a method according to any of claims 13 to 21 or 27 or 28 in building materials, in other materials, in cement, as strengthener, as composite material, as pillars, in houses, in cottages, in buildings, in bridges, in towers, in floors, in roofs, in ceilings, and in walls.

32. Use of a material prepared according to a method according to any of claims 22 to 28 in friezes, on both indoor and outdoor walls, on ceiling, in/on furniture, as balancing humidity in room, as decoration, as wall lawn, as insulation and for acoustic implementation.