WO2019197496A1 - Produits en fibrociment comprenant des fibres naturelles rendues hydrophobes - Google Patents

Produits en fibrociment comprenant des fibres naturelles rendues hydrophobes Download PDF

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Publication number
WO2019197496A1
WO2019197496A1 PCT/EP2019/059154 EP2019059154W WO2019197496A1 WO 2019197496 A1 WO2019197496 A1 WO 2019197496A1 EP 2019059154 W EP2019059154 W EP 2019059154W WO 2019197496 A1 WO2019197496 A1 WO 2019197496A1
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Prior art keywords
fiber cement
fibers
hydrophobized
natural fibers
present
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PCT/EP2019/059154
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English (en)
Inventor
Igor A. Ignatyev
Benoit De Lhoneux
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Etex Services Nv
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Publication of WO2019197496A1 publication Critical patent/WO2019197496A1/fr

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B20/00—Use of materials as fillers for mortars, concrete or artificial stone according to more than one of groups C04B14/00 - C04B18/00 and characterised by shape or grain distribution; Treatment of materials according to more than one of the groups C04B14/00 - C04B18/00 specially adapted to enhance their filling properties in mortars, concrete or artificial stone; Expanding or defibrillating materials
    • C04B20/10—Coating or impregnating
    • C04B20/1051—Organo-metallic compounds; Organo-silicon compounds, e.g. bentone
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
    • C04B28/02—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing hydraulic cements other than calcium sulfates
    • C04B28/04—Portland cements
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
    • C04B2111/00034—Physico-chemical characteristics of the mixtures
    • C04B2111/00129—Extrudable mixtures
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W30/00—Technologies for solid waste management
    • Y02W30/50—Reuse, recycling or recovery technologies
    • Y02W30/91—Use of waste materials as fillers for mortars or concrete

Definitions

  • the present invention relates to fiber cement products comprising natural fibers and methods for production thereof.
  • the present invention further relates to uses of these fiber cement products in the building industry.
  • EP0331666-A1 discloses the treatment of cellulose fibers suitable for use in fiber cement products with amorphous silica particles in the presence of a polyelectrolyte.
  • the present invention provides fiber cement products at least comprising cement, and fibers, characterized in that the fibers at least comprise hydrophobized natural fibers.
  • the hydrophobized natural fibers are present in an amount of between about 3 weight% and about 6weight% compared to the total weight of the dry components of the fiber cement product.
  • hydrophobized natural fibers are hydrophobized natural fibers are hydrophobized cellulose fibers.
  • the hydrophobized natural fibers are natural fibers, which are hydrophobized with a siliconate.
  • the hydrophobized natural fibers are natural fibers, which are hydrophobized with potassium methyl siliconate.
  • the hydrophobized natural fibers have an average length between 2 mm and 3 mm.
  • the fiber cement products further comprise synthetic fibers.
  • the present invention provides processes for the production of a fiber cement product according to the present invention, said processes at least comprising the steps of:
  • a fiber cement slurry at least comprising water, cement and hydrophobized natural fibers
  • step a) of preparing a fiber cement slurry is performed such that the hydrophobized natural fibers are present in an amount of between about 3 weight% and about 6weight% compared to the total weight of the dry components of the fiber cement slurry.
  • the hydrophobized natural fibers are hydrophobized cellulose fibers.
  • the hydrophobized natural fibers are natural fibers, which are hydrophobized with a siliconate.
  • the hydrophobized natural fibers are natural fibers, which are hydrophobized with potassium methyl siliconate.
  • the curing step is performed by means of autoclave-curing or by means of air-curing.
  • the present invention provides uses of the fiber cement products according to the present invention as a building product.
  • the present invention provides uses of the fiber cement product according to the present invention as a fagade element or a roofing element, such as but not limited to a slate.
  • fiber cementitious slurry or "fiber cement slurry” as referred to herein generally refer to slurries at least comprising water, fibers and cement.
  • the fiber cement slurry as used in the context of the present invention may also further comprise other components, such as but not limited to, limestone, chalk, quick lime, slaked or hydrated lime, ground sand, silica sand flour, quartz flour, amorphous silica, condensed silica fume, microsilica, metakaolin, wollastonite, mica, perlite, vermiculite, aluminum hydroxide, pigments, anti-foaming agents, flocculants, and other additives.
  • other components such as but not limited to, limestone, chalk, quick lime, slaked or hydrated lime, ground sand, silica sand flour, quartz flour, amorphous silica, condensed silica fume, microsilica, metakaolin, wollastonite, mica, perlite, vermiculite,
  • the fiber cement slurry can thus be provided by one or more sources of at least cement, water and fibers.
  • these one or more sources of at least cement, water and fibers may operatively be connected to a continuous mixing device constructed so as to form a cementitious fiber cement slurry.
  • a minimum of about 3%, such as about 4%, of the total slurry mass of these cellulose fibers may be used.
  • when exclusively cellulose fibers are used between about 4% to about 12%, such as more particularly, between about 7% and about 10%, of the total slurry mass of these cellulose fibers is used.
  • cellulose fibers are replaced by short mineral fibers such as rock wool, it is most advantageous to replace them in a proportion of 1.5 to 3 times the weight, in order to maintain approximately the same content per volume.
  • long and cut fibers such as glass fiber rovings or synthetic high-module fibers, such as polypropylene, polyvinyl acetate, polycarbonate or acrylonitrile fibers the proportion can be lower than the proportion of the replaced cellulose fibers.
  • cementitious slurry or “cement slurry” as referred to herein generally refer to slurries at least comprising water and cement.
  • the cement slurry as used in the context of the present invention may also further comprise other components, such as but not limited to, limestone, chalk, quick lime, slaked or hydrated lime, ground sand, silica sand flour, quartz flour, amorphous silica, condensed silica fume, microsilica, metakaolin, wollastonite, mica, perlite, vermiculite, aluminum hydroxide, pigments, anti-foaming agents, flocculants, and other additives.
  • Fiber(s) present in the fiber cement slurry as described herein may be for example process fibers and/or reinforcing fibers which both may be natural fibers (typically cellulose fibers) or synthetic fibers (polyvinylalcohol, polyacrilonitrile, polypropylene, polyamide, polyester, polycarbonate, etc.).
  • natural fibers typically cellulose fibers
  • synthetic fibers polyvinylalcohol, polyacrilonitrile, polypropylene, polyamide, polyester, polycarbonate, etc.
  • cement present in the fiber cement slurry as described herein may be for example but is not limited to Portland cement, cement with high alumina content, Portland cement of iron, trass- cement, slag cement, plaster, calcium silicates formed by autoclave treatment and combinations of particular binders.
  • cement in the products of the invention is Portland cement.
  • water-permeable as used herein when referring to a water-permeable (region of a) transport belt generally means that the material of which the water-permeable (region of the) belt is made allows water to flow through its structure to a certain extent.
  • water-permeability as used herein when referring to the water-permeability of a (region of a) transport belt generally refers to the extent or degree to which the material of which the water- permeable (region of the) belt is made, allows water to flow through its structure. Suitable materials for water-permeable transport belts are known to the person skilled in the art, such as but not limited to felts.
  • predetermined and predefined as used herein when referring to one or more parameters or properties generally mean that the desired value(s) of these parameters or properties have been determined or defined beforehand, i.e. prior to the start of the process for producing the products that are characterized by one or more of these parameters or properties.
  • fiber cement layer generally refers to any flat, optionally substantially rectangular, layer or cake essentially consisting of a fiber cement composition and having a thickness of at least about 1 mm, in particular between about 1 mm and 200 mm, more particularly between about 2 mm and about 150 mm, most particularly between about 4 mm and about 100 mm.
  • a “Hatschek fiber cement layer” or a “Hatschek layer” as interchangeably used herein refers to a fiber cement layer (as defined herein), which is produced according to a Hatschek process, which at least comprises the steps of:
  • a "(fiber cement) sheet” as used herein, also referred to as a panel or a plate, is to be understood as a flat, usually rectangular element, a fiber cement panel or fiber cement sheet being provided out of fiber cement material.
  • the panel or sheet has two main faces or surfaces, being the surfaces with the largest surface area.
  • the sheet can be used to provide an outer surface to walls, both internal as well as external a building or construction, e.g. as fagade plate, siding, etc.
  • composition(s) or materials comprising cellulose fibers may refer to any suitable material, and is not necessarily limited to paper, recycled paper, and lignocellulosic fiber sources including, but not confined to, retted and green raw hemp, flax, cereal straws, wheat, barley, rye, oats, rice, pomace, spent grain, wood and/or used cotton.
  • lignocellulosic fiber sources including, but not confined to, retted and green raw hemp, flax, cereal straws, wheat, barley, rye, oats, rice, pomace, spent grain, wood and/or used cotton.
  • the presence of fibers and associated fibrils are part of any suitable material.
  • the present inventors now have found a solution to this problem by using natural fibers, which have been treated with a hydrophobizing agent.
  • a hydrophobizing agent has a sufficiently strong bond with the fiber surface and consequently forms a permanent film, protecting the fiber structure from chemical disruption, such as from disintegration by alkaline pH.
  • the pre-treatment with a hydrophobizing agent does not affect the original strength of the natural fibers.
  • hydrophobized natural fibers are chemically and dimensionally stable in an alkaline cementitious environment. Moreover and most importantly, it has been shown that the resulting fiber cement products as provided by the present invention, which comprise hydrophobized natural fibers, have an improved quality and mechanical strength compared to the known fiber cement products comprising non-treated natural fibers.
  • the present invention provides fiber cement products at least comprising cement and fibers, characterized in that the fibers at least comprise hydrophobized natural fibers.
  • fiber cement products are to be understood as cementitious products comprising cement and at least natural fibers, such as but not limited to cellulose fibers.
  • the fiber cement products are made out of fiber cement slurry, which is formed in a so-called “green” fiber cement product, and then cured.
  • the fiber cement slurry typically comprises water, cement, process and/or reinforcing fibers which are natural fibers and, optionally, synthetic organic fibers.
  • the fiber cement products of the present invention comprise 20 to 95 weight % cement as hydraulic binder.
  • Cement in the products of the invention is selected from the group consisting of Portland cement, cement with high alumina content, Portland cement of iron, trass-cement, slag cement, plaster, calcium silicates formed by autoclave treatment and combinations of particular binders.
  • cement in the products of the invention is Portland cement.
  • the fiber cement products according to the invention optionally comprise further components.
  • These further components in the fiber cement products of the present invention may be selected from the group consisting of water, sand, silica sand flour, condensed silica fume, microsilica, fly-ashes, amorphous silica, ground quartz, the ground rock, clays, pigments, kaolin, metakaolin, blast furnace slag, carbonates, puzzolanas, aluminium hydroxide, wollastonite, mica, perlite, calcium carbonate, and other additives (e.g. colouring additives) etc. It will be understood that each of these components is present in suitable amounts, which depend on the type of the specific fiber cement product and can be determined by the person skilled in the art.
  • Further additives that may be present in the fiber cement products of the present invention may be selected from the group consisting of dispersants, plasticizers, antifoam agents and flocculants.
  • the total quantity of additives is preferably between about 0.1 and about 1 weight % compared to the total initial dry weight of the composition.
  • the fiber cement products of the invention have a thickness of between about 4 mm and about 200 mm, in particular between about 6 mm and about 200 mm, more in particular between about 8 mm and about 200 mm, most in particular between about 10 mm and about 200 mm.
  • the fiber cement products as referred to herein include roof or wall covering products made out of fiber cement, such as fiber cement sidings, fiber cement boards, flat fiber cement sheets, corrugated fiber cement sheets, fiber cement slates and the like.
  • the fiber cement products according to the invention can be roofing or fagade elements, flat sheets or corrugated sheets.
  • the fiber cement products of the present invention are fiber cement slates.
  • the fiber cement products according to the present invention apart from cement, further at least comprise hydrophobized natural fibers.
  • Natural fibers may be obtained from plant, animal, and mineral sources. Those from plant sources include, without limitation, cotton, flax, hemp, sisal, jute, kenaf, and coconut.
  • Cellulose is the main component of vegetable fibers, several of which serve in the manufacture of paper and cloth. Examples include cotton, jute, flax, ramie, sisal, and hemp.
  • Vegetable fibers can be further categorized into the following types:
  • Seed fiber These are fibers collected from seeds or seed cases. Examples include cotton and kapok.
  • Leaf fiber These are fibers collected from leaves. Examples include sisal and agave.
  • Bast fiber or skin fiber These fibers are collected from the skin or bast surrounding the stem of the plant source. They have higher tensile strength than other fibers. Therefore, these fibers are used for durable yarn, fabric, packaging, and paper. Some examples are flax, jute, kenaf, industrial hemp, ramie, rattan, soybean fiber, and even vine fibers and banana fibers.
  • Fruit fiber These fibers are collected from the fruit of the plant, such as coconut (coir) fiber.
  • Stalk fiber These fibers are actually the stalks of the plant. Examples are straws of wheat, rice, barley, and other crops including bamboo and grass. Tree wood is also such a fiber.
  • Cellulose fibers are selected from but not limited to vegetable fibers such as jute, flax, cotton, straw, hemp, bagasse, ramie, and abaca, waste wood pulps and wood pulps for paper making processes.
  • the present invention provides fiber cement products comprising hydrophobized cellulose fibers.
  • these cellulose fibers are obtained from wood pulp, more preferably from chemical wood pulp. Kraft pulp is particularly preferred.
  • the cellulose fibers can be bleached or unbleached.
  • Preferable pulps are processed from softwood, e.g. Pinus Radiata, or from hardwood. Good results can be obtained with cellulose fibers from unbleached, softwood kraft pulp.
  • Cellulose fibers characterized by a Kappa number in the range of 20 to 40 as determined by TAPPI method T236 cm-85, more particularly in the range of 20 to 30 are especially preferred.
  • the cellulose fibers can be refined or unrefined, and can be characterized by a Schopper-Riegler degree as measured according to ISO 5267/1 which is advantageously in the range of 12 to 80.
  • Preference is given to cellulose fibers with a length determined according to TAPPI method T271 in the range of from 0.8 to 4 mm, and preferably from 2 to 3 mm.
  • Cellulose fibers with an alkali soluble content as measured according to TAPPI method T212 below 3.5 wt% are preferred.
  • the fiber cement products of the present invention comprise hydrophobized natural fibers, which are present in an amount of between about 3 weight% and about 6 weight% compared to the total weight of the dry components of the fiber cement product.
  • the fiber cement products of the present invention comprise hydrophobized cellulose fibers, which are present in an amount of between about 3 weight% and about 6 weight% compared to the total weight of the dry components of the fiber cement product.
  • the fiber cement products according to the invention may additionally comprise other inorganic or organic reinforcing fibers in a weight % of about 0.1 to about 5.
  • organic fibers are organic synthetic fibers selected from the group consisting of polypropylene, polyvinylalcohol polyacrylonitrile fibers, polyethyelene, polyamide fibers, polyester fibers, aramide fibers and carbon fibers.
  • inorganic fibers are selected from the group consisting of glass fibers, rockwool fibers, slag wool fibers, wollastonite fibers, ceramic fibers and the like.
  • the fiber cement products of the present invention may additionally comprise fibrils fibrids, such as for example but not limited to, polyolefinic fibrils fibrids % in a weight % of about 0.1 to 3, such as "synthetic wood pulp".
  • the hydrophobized natural fibers are natural fibers, which are hydrophobized with a siliconate.
  • Siliconates comprise at least one Si - OZ, wherein Z is any of elements belonging to alkali metals, such as for example but not limited to sodium or potassium.
  • the natural fibers in the fiber cement products of the present invention are hydrophobized by pre-treatment with an alkali metal organosiliconate, such as an alkali metal methyl siliconate.
  • an alkali metal is potassium or sodium.
  • the natural fibers in the fiber cement products of the present invention are hydrophobized by impregnation with potassium methyl siliconate or with sodium methyl siliconate or with a combination of potassium methyl siliconate and sodium methyl siliconate.
  • the hydrophobized natural fibers are natural fibers, which are hydrophobized with potassium methyl siliconate.
  • hydrophobized natural fibers can be done by any standard method in the art.
  • a method to hydrophobized natural fibers may be to prepare an aqueous dispersion of a siliconate in water, wherein the concentration of siliconate ranges from 0.1% to 20% by weight in water.
  • a suitable dispersion can comprise from 0.1% to 10% of an alkali metal organosiliconate by weight of the aqueous dispersion.
  • a suitable dispersion can comprise from 1% to 7.5% of an alkali metal organosiliconate by weight of the dispersion.
  • a suitable dispersion can comprise from 1% to 5% of an alkali metal organosiliconate by weight of the aqueous dispersion.
  • the aqueous dispersion is then stirred, optionally in the presence of inorganic fillers.
  • Inorganic fillers can optionally act as a catalyst.
  • a suitable inorganic filler is for example but without limitation sodium silicate.
  • the aqueous siliconate dispersion further comprises between 0.5% and 5% of sodium silicate, such as between 1% and 4% of sodium silicate, such as preferably between 1% and 3% of sodium silicate.
  • siliconates react according to a hydrolysis in the presence of carbon dioxide to provide silanols and a metal salt as reaction products.
  • the natural fibers in the form of for example cellulosic material, paper or textile are impregnated or coated by means of impregnation or conventional coating devices for coating, such as for example a type of size press.
  • the step of impregnation is preferably performed by immersion of the cellulosic material in a bath containing the solution comprising the aqueous siliconate dispersion.
  • a bath containing the solution comprising the aqueous siliconate dispersion e.g. a dip bath in which the sheets or rolls are soaked with the solution.
  • the natural (cellulosic) fibers can be pulped in the solution, and the fibers can as such be soaked in the solution.
  • the excess of solution can be drained of, e.g. by dripping out, filtering and/or sucking out the excess of solution.
  • the step of impregnation can also be carried by spraying the solution comprising a siliconate, or by using a blade coater or a roll coater.
  • the step of coating or impregnation is carried out in the presence of a catalyst based on a metal ester.
  • Cellulose fibers with a moisture content in the range between 5 and 20 weight % of water are preferred.
  • Cellulose fibers shaped as a paper sheet are preferably used in the methods according to the invention.
  • the methods according to the present invention optionally comprise an intermediate step of squeezing the siliconate solution from in between the cellulose fiber walls.
  • This step of squeezing can be performed by a method selected from but not limited to methods using a belt press or a screw press, vacuum filtration, compression filtration, ultracentrifugation, heat or vacuum treatment.
  • the step of squeezing in the methods for the treatment of cellulose fibers can be performed by passing the impregnated cellulose fibers through a roller press.
  • Pressing the impregnated fibers through the roller press also called a padding mangle, or by any other means, may force the solution comprising the siliconate to penetrate into the cellulose fiber lumen and even into the cellulose fiber walls such as to obtain precipitated silica in the latter, and squeezes the excess of solution from in between the impregnated cellulose fibers.
  • the step of squeezing in the methods according to the present invention is optionally performed directly after the step of impregnation of the cellulose fibers.
  • a subsequent step of drying may be performed in a ventilated oven (such as a thermic oven, preferably an infrared oven) or under vacuum, and at temperatures possibly ranging from 20°C to 120°C, preferably from 25°C to 80°C.
  • the step of drying of the treated natural fibers may reduce the presence of volatile organic compounds in products which are manufactured with the treated fibers.
  • the dry cellulose fibers still may comprise an amount of solvent, which tends not to evaporate completely. A remaining content of 15%w of solvent in the dried cellulose fibers may be present.
  • the removed solvent and the hydrolysis products are preferably recovered which is economical and ecological.
  • the cellulose fibers can be subjected to additional fiber treatments such as biocide treatment. After deposition of the dispersion on the natural fibers in the form of cellulosic material, paper and/or textile, the impregnated material is heated to remove water. After the treatment, an invisible chemical siliconate coating is obtained on and into the impregnated material, which coating still allows pulping of the material into coated or hydrophobized fibers.
  • biocide treatment After deposition of the dispersion on the natural fibers in the form of cellulosic material, paper and/or textile, the impregnated material is heated to remove water. After the treatment, an invisible chemical siliconate coating is obtained on and into the impregnated material, which coating still allows pulping of the material into coated or hydrophobized fibers.
  • the present invention provides processes for the production of a fiber cement product according to the present invention, the processes at least comprising the steps of:
  • a fiber cement slurry at least comprising water, cement and hydrophobized natural fibers
  • Fiber cement products are manufactured starting from an aqueous fiber cement slurry comprising hydraulic binders, fibers, and possibly fillers and additives. This aqueous suspension is mixed in order to obtain a uniform distribution of the components. The suspension is then dewatered. The so obtained green fresh product can be shaped into a flat sheet, a corrugated sheet or a tube. The green shaped product is then hardened under atmospheric conditions (air-curing) or under specific pressure and temperature conditions (autoclaving).
  • the reinforcing fibers used in the manufacture of the fiber cement products of the present invention are from natural origin.
  • synthetic fibers such as poly(vinylalcohol), polypropylene and polyacrylonitrile fibers, may additionally be present in the fiber cement slurry.
  • the Hatschek process is most widely known for the manufacturing of fiber-cement products.
  • Other manufacturing processes known by the man skilled in the art which can be cited are Magnani, Mazza, flow-on, extrusion and injection.
  • the Hatschek process is based on the use of a dewatering cylindrical sieve. In this way, a layer originating from a diluted suspension of fibers, cement, fillers and additives contained in a vat is transferred to a felt, through a cylindrical sieve; this layer is then enrolled on a forming drum until the required thickness of the sheet is obtained.
  • the fiber cement sheet shaped on the forming drum is cut and removed from the drum, once the desired thickness is obtained.
  • the processes according to the present invention may further comprise the step of cutting the fiber cement products to a predetermined length to form a fiber cement product.
  • Cutting the fiber cement products to a predetermined length can be done by any technique known in the art, such as but not limited to water jet cutting, air jet cutting or the like.
  • the fiber cement products can be cut to any desirable length, such as but not limited to a length of between about 1 m and about 15 m, such as between about 1 m and about 10 m, more particularly between about 1 m and about 5 m, most particularly between about 1 m and about 3 m.
  • processes of the present invention may further comprise additional steps of processing the produced fiber cement products.
  • the fiber cement slurry and/or the fiber cement products may undergo various intermediate treatments, such as but not limited to treatment with one or more hydrophobic agents, treatment with one or more flocculants, additional or intermediate pressing steps, etc.
  • the border strips can optionally be recycled through immediate mixing with the recycled water and directing the mixture to the mixing system again.
  • the obtained fiber cement products are cured.
  • fiber cement products can be allowed to cure over a time in the environment in which they are formed, or alternatively can be subjected to a thermal cure (e.g. by autoclaving or the like).
  • the "green" fiber cement product is cured, typically by curing to the air (air cured fiber cement products) or under pressure in presence of steam and increased temperature (autoclave cured).
  • air air cured fiber cement products
  • autoclave cured products typically sand is added to the original fiber cement slurry.
  • the autoclave curing in principle results in the presence of 11.3 A (angstrom) Tobermorite in the fiber cement product.
  • the "green" fiber cement product may be first pre-cured to the air, after which the pre-cured product is further air-cured until it has its final strength, or autoclave- cured using pressure and steam, to give the product its final properties.
  • the methods for the production of fiber cement products of the invention may further comprise the step of thermally drying the obtained fiber cement products.
  • the fiber cement product being a panel, sheet or plate, may still comprise a significant weight of water, present as humidity. This may be up to 10 even 15 %w, expressed per weight of the dry product.
  • the weight of dry product is defined as the weight of the product when the product is subjected to drying at 105°C in a ventilated furnace, until a constant weight is obtained.
  • the fiber cement product is dried. Such drying is done preferably by air drying and is terminated when the weight percentage of humidity of the fiber cement product is less than or equal to 8 weight %, even less than or equal to 6 weight %, expressed per weight of dry product, and most preferably between 4 weight % and 6 weight %, inclusive.
  • the fiber cement products comprising the cellulose fibers which have been treated according to the method of the present invention may have an improved durability over fiber cement products not comprising the treated cellulose fibers according to the present invention.
  • the amount of treated cellulose fibers in the fiber cement products is preferably in the range of 0.5 to 8 weight % with respect to the dry weight of the hydraulic composition, preferably between 3 and 6 weight % with respect to the dry weight of the hydraulic composition.
  • the dry weight of the hydraulic composition is to be understood here as the weight of the hydraulic composition before dilution with water necessary to prepare the fiber cement slurry which is used in the manufacture of the fiber cement product.
  • the hydrophobized natural fibers are hydrophobized cellulose fibers.
  • the hydrophobized natural fibers are natural fibers, which are hydrophobized with a siliconate.
  • the hydrophobized natural fibers are natural fibers, which are hydrophobized with potassium methyl siliconate.
  • the present invention provides fiber cement products obtainable by the methods for the production of fiber cement products according to the present invention.
  • the present invention provides fiber cement products, and in particular fiber cement building materials, comprising hydrophobized natural fibers.
  • the present invention provides uses of hydrophobized natural fibers for the preparation of fiber cement compositions and/or for the manufacture of fiber cement products, such as in particular fiber cement building materials.
  • the present invention provides uses of the fiber cement products of the present invention as building materials.
  • These fiber cement building materials may be porous materials comprising one or more different materials such as a gypsum composite, cement composite, geopolymer composite or other composites having an inorganic binder.
  • the surface of the material may be sanded, machined, extruded, molded or otherwise formed into any desired shape by various processes known in the art.
  • the fiber cement building materials may be fully cured, partially cured or in the uncured "green" state.
  • Fiber cement building materials may further include gypsum board, fiber cement board, fiber cement board reinforced by a mesh or continuous fibers, gypsum board reinforced by short fibers, a mesh or continuous fibers, inorganic bonded wood and fiber composite materials, geopolymer bonded wood and fiber boards, concrete roofing tile material, and fiber-plastic composite material.
  • the fiber cement products of the invention are fiber cement sheets produced by the processes of the present invention and can be used to provide an outer surface to walls, both internal as well as external a building or construction, e.g. as fagade plate, siding, etc.
  • the present invention provides uses of the fiber cement product according to the present invention as a fagade element or a roofing element, such as but not limited to a slate.
  • a sample of a paper sheet of unbleached kraft cellulose was impregnated with a solution comprising 10% or 3% of sodium methyl siliconate by immersion in a bath. In some instances, the solution further contained 1% sodium silicate or 3% sodium silicate. The excess solution was removed from the wet paper using a roller press and subsequently the material was dried in an infrared oven. b) Preparation of fiber cement test samples
  • the fibers treated as explained in the preceding paragraph were dispersed in water using a laboratory desintegrator and mixed afterwards with the other components of the hydraulic composition comprising ordinary Portland cement, amorphous calcium carbonate and amorphous silica.
  • a flocculant based on polyacrylamide was added and the mixture was poured immediately after in a mould of a filter press of dimension 70*200 mm and the excess water was removed by pressure.
  • the fiber cement test samples were subjected to 20 consecutive ageing cycles of 15 hours per cycle.
  • One ageing cycle comprised the following steps:
  • Pre-treated hydrophobized cellulose fibers were redispersed in water and used for the manufacture of fiber cement composite test samples (see Table 1).
  • fiber cement products according to the present invention which comprise hydrophobized cellulose fibers showed at least comparable and even improved strength properties when compared to fiber cement products comprising untreated non- hydrophobized fibers.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Ceramic Engineering (AREA)
  • Materials Engineering (AREA)
  • Structural Engineering (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Inorganic Chemistry (AREA)
  • Curing Cements, Concrete, And Artificial Stone (AREA)

Abstract

La présente invention concerne des produits en fibrociment comprenant des fibres naturelles et leurs procédés de production. La présente invention concerne en outre des utilisations de ces produits en fibrociment dans l'industrie du bâtiment. En particulier, la présente invention concerne des produits en fibrociment comprenant au moins du ciment et des fibres, caractérisés en ce que lesdites fibres comprennent au moins des fibres naturelles rendues hydrophobes. En outre, la présente invention concerne des procédés de production de produits en fibrociment comprenant des fibres rendues hydrophobes, comprenant au moins les étapes consistant : a. à préparer une suspension épaisse de fibrociment comprenant au moins de l'eau, du ciment et des fibres naturelles rendues hydrophobes ; b. à produire un produit de fibrociment cru au moyen d'un procédé de fabrication de fibrociment choisi dans le groupe constitué d'un procédé de Hatschek, d'un procédé de Magnani, d'un procédé par écoulement, d'un procédé par extrusion et similaire ; et c. à durcir le produit de fibrociment cru.
PCT/EP2019/059154 2018-04-11 2019-04-10 Produits en fibrociment comprenant des fibres naturelles rendues hydrophobes WO2019197496A1 (fr)

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EP18166863.3 2018-04-11

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114394808A (zh) * 2022-02-07 2022-04-26 武汉理工大学 一种矿化基复合纤维水泥板及其制备方法和应用
CN115504716A (zh) * 2022-10-10 2022-12-23 湖北工业大学 一种灭菌抗病毒耐沾污抹面砂浆及其制备方法

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0331666A1 (fr) 1988-02-18 1989-09-06 Eternit-Werke Ludwig Hatschek AG Procédé de traitement de fibres cellulosiques ainsi que de produits de ciment contenant des fibres et compositions pour leur fabrication
WO2004113248A2 (fr) * 2003-06-20 2004-12-29 James Hardie International Finance B.V. Article de construction durable et son procede de fabrication
WO2005012203A2 (fr) * 2003-08-01 2005-02-10 Aalborg Universitet Procede de preparation de materiaux contenant des systemes liants derives de silice amorphe et de bases
EP2796434A1 (fr) * 2013-04-23 2014-10-29 Redco NV Procédé de traitement de fibres de cellulose

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0331666A1 (fr) 1988-02-18 1989-09-06 Eternit-Werke Ludwig Hatschek AG Procédé de traitement de fibres cellulosiques ainsi que de produits de ciment contenant des fibres et compositions pour leur fabrication
WO2004113248A2 (fr) * 2003-06-20 2004-12-29 James Hardie International Finance B.V. Article de construction durable et son procede de fabrication
WO2005012203A2 (fr) * 2003-08-01 2005-02-10 Aalborg Universitet Procede de preparation de materiaux contenant des systemes liants derives de silice amorphe et de bases
EP2796434A1 (fr) * 2013-04-23 2014-10-29 Redco NV Procédé de traitement de fibres de cellulose

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114394808A (zh) * 2022-02-07 2022-04-26 武汉理工大学 一种矿化基复合纤维水泥板及其制备方法和应用
CN115504716A (zh) * 2022-10-10 2022-12-23 湖北工业大学 一种灭菌抗病毒耐沾污抹面砂浆及其制备方法
CN115504716B (zh) * 2022-10-10 2023-04-07 湖北工业大学 一种灭菌抗病毒耐沾污抹面砂浆及其制备方法

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