ES2552246B2 - Product of composite material of inorganic binder and vegetable fibers, and method for its manufacture - Google Patents

Abstract

Product of composite material of inorganic binder and cellulosic vegetable fibers; said product in the form of a plate, comprising: - a first outer layer (1) consisting of a paste rich in binder and without reinforcing fibers, - an inorganic matrix (2) mineral, containing cement, lime or plaster, material pozzolanic and fluidizing additive; and includes several layers (21) of non-woven fabric (T), superimposed, with a thickness of 2 to 4 millimeters, with a weight between 200 and 600 gr / m {sup, 2}; constituted by cellulosic vegetable fibers of a length between 3 and 6 centimeters, joined by punching and - a second outer layer (3) consisting of a paste rich in binder, without reinforcement fibers, forming a second face of the plate. The invention includes a manufacturing process for said product.

Description

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DESCRIPTION

Product of composite material of inorganic binder and vegetable fibers, and method for its manufacture.

Object of the invention.

The object of the invention is a composite material product, based on inorganic binder and nonwoven fabric of cellulosic vegetable fibers that, in addition to presenting good physical and mechanical characteristics, is a sustainable material, low cost for construction and that It allows machining or polishing by at least one of its external faces.

The invention also includes a method for manufacturing said product.

Field of application of the invention.

This product is applicable in the field of construction, specifically and although not limited to drywall, ventilated façade and medianerla coverings or cover plates, flooring and street furniture.

State of the art.

There is currently a large number of antecedents in the market related to complex panels that combine materials with different characteristics and functions.

In document AU2009333357-B2 and US2010319832-A1 a material is described for manufacturing panels of mineral matrix (cement, plaster) covered with synthetic fabric by means of a transport system on the upper and lower sides of the core of the paste matrix. The manufacturing system allows the fabric to be incorporated into the dough. The reinforcement system improves the traction and flexion behavior of the material. The reinforcing material is polymeric and can be incorporated in the form of fabric, nonwoven or paint. This material contains only two layers of reinforcement on the outer faces of the board and does not incorporate reinforcement on the inside.

In US 2008/0200086 A1 a cement panel and manufacturing methods thereof are described. It includes a cement core, a plurality of warp threads, weft threads and a coating. The system is very similar to that of patent AU2009333357-B2 and US2010319832-A1 described above, where a woven or nonwoven of synthetic fibers, in this case of fiberglass, is used to line a matrix core of mineral binder (Portland cement or that). This panel contains only two layers of reinforcement of a synthetic material on the external faces of the panel.

US 2011/0053445 A1 describes a method of manufacturing smooth reinforced cement boards. The material is very similar to that of patent AU2009333357 -B2 and US2010319832 -A1 described above, where a woven or nonwoven of synthetic fibers, in this case of glass fiber, is used to line a matrix core of mineral binder (Portland cement or that). In this case, an open mesh kevlar synthetic fiber reinforcement embedded in the core is used thanks to a second fiberglass nonwoven reinforcement. On top of this non-woven, it incorporates a new layer of inorganic binder mortar. This board contains two layers of reinforcement together, of two different synthetic materials, on each of the outer faces of the board; and does not incorporate reinforcement layers in the inner part.

US2004219845-A1 (WO2004097091-A1) describes a reinforced cement panel useful in the tile industry comprising only two layers of reinforcement in the

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external faces of the board. This panel does not incorporate reinforcement in the internal part. The reinforcement material is a synthetic material, preferably carbon fiber.

WO9301931-A1; AU9224043-A; EP597982-A1; JP7500058-W describes a composite panel consisting of a core of foamed insulating material of the expanded polystyrene type with outer, upper and lower layers of Portland cement reinforced with nonwoven. The manufacturing system consists of placing the cement mortar on the insulating core to which the reinforcement nonwoven is incorporated. While the cement is fresh, the assembly is compressed to make the composite panel. In this panel the outer reinforcement layer of the material only incorporates a non-woven reinforcement layer.

WO9304242-A1 describes an insulating panel consisting of a thick layer (20-40mm) of rock wool with a binder and fiber reinforcement placed in two layers. The first is formed by a layer of powder binder that is activated by a water spray. Over this layer of fresh binder is added a layer of fiber reinforced binder formed by a first layer of fresh binder, a second layer of fiber reinforcement that can be woven, non-woven or mesh, of organic or inorganic material, preferably fiber of glass or polyester or polypropylene and, finally, a last layer of fresh binder. This panel only incorporates a single layer of reinforcement material that is not made of natural fibers.

WO 2011060684-A1 describes a panel for ventilated façade formed by a succession of different layers: decorative layer of paints or external laminar coatings; Multifunctional material layer consisting of a fiber cement board with special aggregates and various additives to improve its bearing capacity; special adhesive layer. Thermal insulation layer of expanded or extruded polystyrene. This multilayer panel is not formed by equal layers of cement plus reinforcement but rather it is different layers stacked with different functions. Cement reinforcement is based on artificial organic short fiber (polypropylene)

The technical problem that arises is the development of a composite material of mineral matrix and non-woven reinforcement of long natural fibers with a surface suitable for polishing or machining and with adequate characteristics to achieve a correct impregnation of several layers of vegetable fiber of cellulosic type in a mineral matrix, a strong union between them; and a high mechanical resistance of the panel or finished product.

Description of the invention.

The product of composite material of inorganic binder and vegetable fibers; said product being constituted in the form of a plate; It has the particularity of comprising: - a first outer layer consisting of a paste rich in binder and without reinforcement fibers, forming a first face of the plate; - an inorganic mineral matrix, containing binder (cement, lime or plaster), pozzolanic material and fluidizing additive; said matrix including several layers of nonwoven fabric, supposed, with a thickness of 2 to 4 millimeters, of a weight between 200 and 600 gr./m2; each layer of nonwoven fabric being constituted by cellulosic vegetable fibers of a length between 3 and 6 centimeters, joined by punching; and - a second outer layer consisting of a paste rich in binder and without reinforcing fibers, forming a second face of the plate.

The definition of the faces of the plate by means of the first and the second extreme layer of paste rich in binder allows said faces to be polished, machined or painted without the fibers going outside and incorporating active particles that improve their functional capabilities (oxides of titanium for its known catalytic properties, particles of

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nanometric dimensions such as carbon nanowires, CO2 absorbent materials, use of pigmentation to color the surface, ...).

The cellulosic vegetable fibers are arranged in the form of nonwoven fabrics based on coarse natural fibers (flax and hemp, although other types of long fiber can be used) stabilized by carding and subsequent punching. The result is a set of cellulosic vegetable fibers grouped in random directions in their own plane with a high degree of porosity, thicknesses of a few millimeters (2 - 3 mm.) And a grammage preferably between 300 and 325 gr./m2.

In one embodiment of the invention the inorganic matrix comprises at least three layers of nonwoven fabric of cellulosic vegetable fibers and preferably between 3 and 6 layers.

The pozzolanic material incorporated in the inorganic matrix, carrier of the nonwoven layers of cellulosic vegetable fibers, constitutes a reducer of the calcium hydroxide content of the matrix and is the component that has to provide durability to the mixture.

This pozzolanic material can be any pozolanic product or by-product incorporated, or not, in the commercial cement itself, such as silica smoke, metacaolln, fly ash, blast furnace slag or natural pozzolana. In each case, its activity should be measured to achieve the desired durability effect.

Water is the product that facilitates the mixing of the matrix components. From the strictly chemical point of view, an amount proportional to the weight of cement of approximately 27% is needed to hydrate the cement, that is, a ratio between water and cement (a / c) of 0.27. However, from the point of view of mixing and according to the application, greater water content will be required. In any case, the water content must be the minimum possible since the excess of water generates porosity and loss of resistance and durability.

The superfluidifying additive incorporated in the inorganic matrix is responsible for providing greater homogeneity and fluidity to the matrix so that it can easily penetrate and impregnate the nonwoven layers of cellulosic vegetable fibers during the manufacture of the product. This additive is about surfactants that disperse cement particles and improve fluidity.

The outer layers of the plate may contain a fine aggregate to improve the hardness and appearance of the surface, in addition to other types of active particles to improve its functionality.

According to the invention, the method of manufacturing the product described above comprises the following steps:

a) the preparation of non-woven layers of cellulosic vegetable fibers of a length between 3 and 6 centimeters, joined by punching, with a weight between 200 and 600 gr./m2 and a thickness of 2 to 4 millimeters;

b) the preparation of an inorganic mineral matrix consisting of a mixture of cement, lime or plaster, pozzolanic material, fluidizing additive and water;

c) the soaking of the nonwoven layers of cellulosic plant fibers in the inorganic matrix and their superposition;

d) the application on one or two opposite faces of the matrix carrying the nonwoven layers of cellulosic vegetable fibers of a paste rich in binder and without reinforcing fibers, intended to form the respective outer face of a plate of product;

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e) the elimination of possible air bubbles by vacuum molding and pressing the plate;

f) curing of the plate in a humid chamber or in an autoclave and

g) optionally, the application on at least one of the external layers of the plate of a machining treatment, or polishing or painting and, where appropriate, the incorporation of active particles to obtain some specific functionality.

The proportion by weight of water and cement a / c used in the preparation of the inorganic binder is between 0.8 and 1.2.

Description of the figures.

To complement the description that is being made and in order to facilitate the understanding of the features of the invention, a set of drawings is attached to the present specification in which, with an illustrative and non-limiting nature, the following has been represented:

- Figure 1 shows a schematic profile view of an example of realization of the product of composite material of inorganic binder and stepped sectional vegetable fibers.

- Figure 2 schematically shows an example of the manufacturing method of the product at the industrial level.

Preferred embodiment of the invention.

As can be seen in Figure 1, the product object of the invention is constituted in the form of a plate and has a first outer layer (1) consisting of a paste rich in binder, an inorganic mineral matrix (2) that includes several layers (21 ) of non-woven fabric (T) superimposed and constituted by cellulosic vegetable fibers; and a second outer layer (3) consisting of a paste rich in binder.

The first and second outer layer (1, 3) lacking fibers are suitable for polishing or external machining of the plate, it being provided that said outer layers (1, 3) may contain a fine aggregate or other type of active particles , normally titanium oxides for self-cleaning by catalysis of the contamination particles and mineral pigments to color the surface, without excluding other types of active particles such as those described above.

The layers (21) of nonwoven fabric (T) have a thickness of 2 to 4 millimeters and a weight between 200 and 600 gr / m2, preferably between 300 and 325 gr / m2.

In the exemplary embodiment shown in Figure 2, the method of manufacturing the aforementioned product is schematically shown from a roll (R) of nonwoven fabric (T) of cellulosic vegetable fiber as it emerges from a weaver responsible for its preparation.

This non-woven fabric (T) has sufficient strength to be stretched by rollers during the manufacturing process.

The non-woven fabric (T) is passed several times through a bowl (C) containing a paste (P) of fine binder forming the mineral inorganic matrix, until the non-woven fabric (T) is soaked in the pulp.

The impregnated nonwoven web (T) is subjected to a vacuum process (V) that removes excess water and is then rolled into a large cylinder (C1) that turns as many turns as layers (21) of tissue Non-woven (T) are necessary to form the matrix (2) of the plate.

Once the layers (21) of nonwoven fabric, impregnated in the paste destined to form the mineral inorganic matrix (2) are obtained, the roll is cut parallel to the cylinder guideline (C1) and it is detached towards a tray (B) containing a first outer layer (1) 10 of the product, consisting of a paste rich in binder.

Subsequently, the second outer layer (3) of binder-rich paste, which may include active particles, is applied on the upper face of the matrix (2) with the layers (21) of non-woven fabric.

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Then the set of the constituent layers of the plate is pressed and molded for 10 minutes, after which it passes to cure in a humid chamber or in an autoclave.

Subsequently and optionally, a polishing, painted or definitive machining treatment can be applied on at least one of the outer layers (1, 3) of the plate

surface finish

Once the nature of the invention has been sufficiently described, as well as an example of preferred realization, it is stated for the appropriate purposes that the materials, shape, size and disposition of the described elements may be modified, provided that

this does not imply an alteration of the essential characteristics of the invention that are claimed below.

Claims (6)

5 10 fifteen twenty 25 30 35 40 Four. Five fifty 1. - Product of composite material of inorganic binder and cellulosic vegetable fibers; said product being constituted in the form of a plate; characterized in that it comprises: - a first outer layer (1) consisting of a paste rich in binder and without reinforcing fibers, forming a first face of the plate; - an inorganic mineral matrix (2), containing cement, lime or gypsum, pozzolanic material and fluidizing additive; said matrix including several layers of non-woven fabric (T), superimposed, with a thickness of 2 to 4 millimeters, with a weight between 200 and 600 gr / m2; each layer of nonwoven fabric (T) being constituted by cellulosic vegetable fibers of a length between 3 and 6 centimeters, joined by punching and - a second outer layer (3) consisting of a paste rich in binder, without reinforcing fibers, forming a second face of the plate. 2. - Product, according to claim 1, characterized in that at least one of the first and second outer layer (1, 3) contains a fine aggregate or other type of active particles. 3. - Product, according to claim 1, characterized in that the inorganic matrix (2) comprises at least three layers of nonwoven fabric (T) of cellulosic vegetable fibers. 4. - Product, according to claim 1, characterized in that the weight of nonwoven fabric (T) is between 300 and 325 gr / m2. 5. - Product manufacturing process of the preceding claims; characterized in that it comprises: a) the preparation of layers (21) of nonwoven fabric (T) of cellulosic vegetable fibers of a length between 3 and 6 centimeters, joined by punching, with a fiber concentration between 200 and 600 gr / m2 and a thickness of 2 to 4 millimeters; b) the preparation of an inorganic mineral matrix (2) consisting of a mixture of cement, lime or plaster, pozzolanic material, fluidizing additive and water; c) soaking the layers (21) of nonwoven fabric (T) of plant fibers in the inorganic matrix (2) and their superposition; d) the application on one or both of the opposite faces of the inorganic matrix (2) bearing the layers (21) of non-woven fabric of plant fibers of an external layer (1, 3) of binder-rich paste, intended for forming the respective outer face of a product plate; e) the elimination of possible air bubbles by vacuum molding and pressing the plate; f) curing of the plate in a humid chamber or in an autoclave and g) optionally, the application on at least one of the outer layers (1, 3) of the plate of a machining treatment, or polishing or painting or the incorporation of active particles that improve its functionality. 6.- Process, according to revindication 5, characterized in that the proportion by weight of water and cement used in the preparation of the inorganic binder is between 0.8 and 1.2.