FR2925041A1 - AGGLOMERATED CELLULOSE FIBER BLOCKS. - Google Patents

Abstract

The present invention relates to blocks of agglomerated cellulose fibers, their uses, in particular for making constructions and a method of manufacturing these blocks.

Description

The present invention relates to blocks of agglomerated cellulose fibers, their uses, in particular for making constructions and a method of manufacturing these blocks.

The production of agglomerated blocks of wood is described in document WO2006 / 120353. This application describes a process in which an initial mixture comprising wood particles and a hydraulic binder is maintained in a pressurized mold throughout the setting time of the binder. The blocks thus obtained have good strength and can be used in the field of construction.

The present application proposes an alternative to the blocks described in the prior art. It results in particular from the demonstration that resistant agglomerated blocks can be produced from cellulose fibers. It also shows that such blocks are perfectly suited for use in the field of construction. The invention thus proposes a solution to the treatment of numerous waste or materials based on cellulose fibers, and allows the production of agglomerated blocks having unexpected strength and density qualities, compatible with the production of structural elements for the construction.

The present invention thus provides, for the first time, blocks of agglomerated cellulose fibers comprising a high proportion of cellulose fibers and having certain characteristics close to those of raw wood.

An object of the invention thus resides in a block of compressed agglomerated cellulose fibers, comprising cellulose fibers and a hydraulic binder, and advantageously having a high density. The blocks of the invention are advantageously obtained by a process in which an initial mixture comprising cellulose fibers and a hydraulic binder is kept under pressure for the duration of setting of the binder. The blocks of the invention have excellent mechanical properties, especially in terms of resistance to compression, water and fire, and are entirely suitable for use as a construction element. These blocks are particularly advantageous compared to existing materials, such as concrete, especially because of their reduced weight.

A particular object of the invention thus resides in a block of compressed agglomerated cellulose fibers, characterized in that it comprises cellulose fibers and a hydraulic binder and in that it is obtained by a process in which an initial mixture comprising cellulose fibers and a hydraulic binder is maintained under pressure throughout the setting time of the binder, the cellulose fibers representing at least 65%, preferably from 65% to 95% approximately, of the total volume of the dry matter of the initial mixture. Another object of the invention relates to a block of compressed agglomerated cellulose fibers, characterized in that it comprises cellulose fibers and a hydraulic binder, in that it is obtained by compression of an initial mixture comprising at least 65% of cellulose fibers, by volume of dry matter, and in that it has a density greater than about 500 kg / m3.

The blocks of the invention preferably have a density greater than about 500 kg / m 3, typically greater than about 600 kg / m 3, preferably about 800 kg / m 3. Furthermore, the blocks of the invention are preferably prepared from a mixture comprising at least about 65%, by volume of dry matter, of cellulose fibers, preferably from about 65% to about 95%, typically from 75 to 95%.

In addition, the blocks of the invention advantageously have a puncture compression strength greater than 0.5 mPa, typically exceeding 3 mPa, for a block of 5 cm 3. Preferably, the blocks of agglomerated wood are produced from a mixture comprising, for a total of 100% representing the volume of the dry matter, from 65% to 95% of cellulose fibers and from 5% to 35% approximately of hydraulic binder, and a quantity of water between 10% and 30% of the total volume of the dry matter. The cellulose fibers used may be based on sludge or paste obtained after recycling and / or treatment of old paper, new paper pulp, cellulose tissue wadding for fabrics or any other quality of cellulose fibers. The cellulose fibers can be used in admixture with vegetable fibers. The hydraulic binder used may for example be based on cement, lime or plaster, preferably based on cement. In this respect, it is possible to use any type of commercially available cement, such as for example standard cements (in particular a 32/5 cpj cement) or any other quality of cement. In a preferred embodiment of the invention, the cellulose fibers comprise cellulose fibers derived from sludge or pulp for recycling old paper, possibly mixed with vegetable fibers in order to increase the mechanical resistance to compression. It may be in particular cellulose fibers obtained, for example by recycling and treatment of old paper. Advantageously, the cellulose fibers come from sludge or pulp recycling and / or treatment of old paper commonly called Calciton, and are essentially free of toxic or polluting elements. It is, of course, possible to use cellulose fiber blends from the recycling and processing of old paper, new paper pulp or cellulose tissue wadding.

In a particular embodiment, cellulose fibers are used in ground sludge or pulp and dried in order to obtain a homogeneous mixture with the hydraulic binder and thus allow a better mechanical strength in finality.

In a particular embodiment, a proportion of the cellulose fibers is composed of plant fibers. Thus, in particular blocks according to the invention, the volume of the cellulose fibers is reduced between 5% and 35% and compensated by the same percentage by the addition of vegetable fibers, for example of the hemp, linen, wood, etc. type. The plant fiber of hemp is more particularly used because it also has a natural fungicidal and insecticidal power, and not chemical. The vegetable fiber of the wood in fine particle makes it possible to reinforce the mixture by longer fibers and thus to obtain a greater mechanical resistance. Thus, in a particular embodiment, the blocks of agglomerated cellulose fibers are produced from a mixture comprising, for a total of 100% representing the volume of the dry matter, from 40% to approximately 90% of cellulose fibers, from about 5% to about 35% plant fiber and from about 5% to about 25% hydraulic binder, and a water amount of from 10% to 30% of the total dry matter volume. In a particular embodiment, the block also contains one or more adjuvants, making it possible to adapt or improve the properties of the blocks. Mention may in particular be made of adjuvants for coloring, acceleration or retardation of binding of the binder, water-repellency, fireproofing, fungicidal or insecticidal treatment, fluidification of the mixture, faster curing, obtaining a high performance mixture, reinforcing fibers of the agglomerated block or a mineral filler. Any adjuvant usable in the concrete can be used in the present invention. The blocks of the invention can have a varied shape and thickness, depending on the desired use (load-bearing wall, panel, floor, roof, beam, street furniture or habitat, etc.).

An essential advantage of the agglomerated block according to the invention is that it contains a high proportion of cellulose fibers, thanks to the maintenance of the pressure, which makes it possible to obtain a dense material with relatively little binder. It thus has insulation qualities close to those of the raw wood used initially, as well as a good mechanical resistance that makes it suitable for use in the construction of load-bearing structures used for buildings.

Another object of the invention resides in a process for preparing an agglomerated block as defined above. In a particular variant, the process for preparing a block of agglomerated cellulose fibers comprises the steps of forming or pouring into a mold a mixture comprising cellulose fibers and a hydraulic binder, moistened with water, and then apply and maintain the mixture under pressure throughout the setting time of the binder. Another particular object of the invention thus resides in a block of compressed agglomerated cellulose fibers, comprising cellulose fibers and a hydraulic binder, obtained by a process in which a dry and homogeneous initial mixture comprising cellulose fibers and a binder hydraulically, moistened with water, is poured into a mold and kept under pressure for the duration of setting binder. Preferably, the initial mixture comprises, for a total of 100% representing the volume of dry matter, from about 65% to about 95% of cellulose fibers, from about 5% to about 35% of hydraulic binder, and a quantity of water between 10% and 30% water of the total volume of dry matter. In addition, as indicated above, the mixture may contain one or more adjuvants chosen, for example, from adjuvants for coloring, accelerating or delaying binding of the binder, water-repellency, fireproofing, fungicidal or insecticidal treatment. blending of the mixture, faster curing, obtaining a high performance blend, reinforcing fibers of the agglomerated block or a mineral filler. The pressure applied to the mixture may be adapted by those skilled in the art, depending on the properties and the desired use. In a particular embodiment, it is less than about 1 mPa, preferably less than about 0.8 mPa, and may be for example 0.1 mPa. An advantage of the invention is that this method is simple to implement, requiring no complex physical or chemical treatment which would increase the costs and time of implementation. Mixing the ingredients dry, before adding water, is also an advantageous and important aspect of the process, making it possible to obtain particularly homogeneous and resistant blocks. In a particular embodiment of the process, the sludge or pulp cellulose fibers are crushed and dried in order to obtain a homogeneous mixture with the hydraulic binder and thus allow a better mechanical strength at the end.

The blocks thus produced can be stored or stored in any suitable condition. In the storage phase, the parts or molds can be placed in a hardening chamber to accelerate drying and thus save time. The mixture can be molded into molds of various shapes and sizes. Preferably, the agglomerated cellulose fiber blocks are molded into molds having a lid for pressing and the mold has a lid locking means at a predetermined height to maintain the pressure until the binder is set.

Another particular object of the invention resides in the use of a block 30 as defined previously as a construction element in the field of the building. The blocks can be used for the realization of walls, partitions, beams, beams, vaults, floors, etc.

Another object of the invention resides in adhesive mortars based on cellulose fibers, wood fibers and / or vegetable fibers. Thus, a particular object of the invention relates to a cellulose fiber adhesive mortar, characterized in that it comprises cellulose fibers and a hydraulic binder and in that it is obtained by the dry blending of the cellulose fibers. and hydraulic binder and then moistened with water.

Another subject of the invention relates to a wood fiber adhesive mortar, characterized in that it comprises wood fibers and a hydraulic binder and in that it is obtained by dry blending of the particle wood fibers. fine and hydraulic binder and then moistened with water. Another object of the invention relates to a plant fiber adhesive mortar, characterized in that it comprises vegetable fibers and a hydraulic binder and in that it is obtained by dry blending the fine-particle vegetable fibers and the hydraulic binder and then moistened with water. Advantageously, the adhesive mortar comprises different vegetable fibers mixed together, for example of the hemp, linen, wood, cellulose, etc. type, and a hydraulic binder, and is obtained by dry blending the fine-particulate plant fibers and the binder. hydraulic and then moistened with water. In the adhesive mortar according to the invention, the binder is preferably based on cement, lime or plaster. Furthermore, the adhesive mortar may also contain one or more adjuvants for coloring, accelerating or delaying binding of the binder, water repellency, fireproofing, fungicidal or insecticidal treatment, fluidification of the mixture, faster curing or to obtain a high performance mix.

The invention will be better understood and other features and advantages will appear more clearly on reading the detailed description given below by way of example.

A typical method of making the blocks is as follows. For a total of 100% representing the total volume of the dry matter, a large proportion of cellulose fibers representing a volume of the order of 65% to 95% is mixed with a hydraulic binder, for example cement, lime or plaster, whose volume of the dry matter is of the order of 5% to 35%. The dry mixture is then moistened. In this respect, the dosage of water varies according to the nature of the cellulose fibers, it can be of the order of 10% to 30% of the total volume of dry matter. In a particular mode of implementation, the method of making the blocks is as follows. For a total of 100% representing the volume of the cellulose fibers, the dry matter of the hydraulic binder and the vegetable fibers, a significant proportion of cellulose fibers representing a volume of about 40% to 90% and a proportion of plant fibers representing a volume of the order of 5% to 35% are mixed with a hydraulic binder, for example cement, lime or plaster, the volume of the dry matter is of the order of 5% to 25%. The water dosage varies according to the nature of the cellulose fibers, it can be of the order of 10% to 30% of the total volume of dry materials (hydraulic binder, cellulose fibers and vegetable fibers). Then this wet mixture is poured into a mold and then is strongly compressed in a volume proportion of for example between 5% and 50%, to make the material very compact. Under the effect of this high pressure, most of the residual air is removed forming a block of compacted agglomerated cellulose fibers. Maintaining the pressure until the binder is set is essential to maintain the compactness of the agglomerate, the highly compressed and interlocked cellulose fibers tending to elastically straighten until the binder has not frozen the final shape. This high sustained compression gives a dense material providing interesting characteristics, including good resistance to compression punching, with a value greater than 1 mPa, typically of the order of 0.5 to 5 mPa, for example measured on a block of 5 cm3. This block has a thermal insulation power close to that of wood, a fire resistance improved by the high density and the coating of cellulose fibers by the binder, and having no deformation or degradation by water. In addition, the faces of the block strongly compressed against the walls of the mold are substantially smooth and follow reliefs that can be made on the walls, which allows for finished blocks directly after demolding with smooth faces having embossed decorations. These blocks have a density of between 500 and 1200 kg / m3 which is significantly lower than that of the agglomerated concrete blocks, which facilitates their handling and reduces the weight of the structures themselves. Blocks can also be made, each covering a larger partition surface for faster mounting. In addition, as for wood, these blocks can be cut, drilled, and receive nails or screws. In addition, various adjuvants can be added for the acceleration or retardation of the setting of the binder, the coloring of the material, its water repellency, its fireproofing, the fungicidal or insecticidal treatment, the fluidification of the mixture, for a faster cure or for get a high performance mix. Complements may also be added to enhance the mechanical strength of the block, such as metal fibers (notched steel, corrugated, stainless amorphous cast iron), synthetic fibers (glass fiber, carbon, polypropylene). Optical fibers giving a luminous effect can be added for decoration. A mineral filler such as sand or silica fume can be incorporated into the mixture to increase the hardness of the block. However, the addition of such a load is not a preferred embodiment because increasing the weight of the material which thus becomes equivalent to the concrete.

Preferably, the fragmented cellulose fibers incorporated come from the papermaking industries. These cellulose fibers are of good quality. These cellulose fibers require grinding and drying treatment before use. These cellulose fibers give the block flexibility and good dimensional stability. In general, the agglomerated cellulose fiber blocks made according to the invention may comprise depressions to reduce the amount of material used and the weight. They may also include holes according to the thickness or surface grooves which end to end from one block to the other constitute passages for electrical ducts or pipes for example. In addition, it is common to use a dry mixture of fine sand and cement, then moistened with water, to produce a mortar adhesive for the assembly of building blocks together.

The hydraulic binder used to make the adhesive mortar may be based on cement, lime or plaster, preferably based on cement. In this respect, it is possible to use any type of commercially available cement, such as for example standard cements (in particular a 32/5 cpj cement) or any other quality of cement.

Preferably, a dry mixture of fine-particle cellulose fibers and cement, then moistened with water, makes it possible to produce an adhesive mortar for the assembly of building blocks made of cellulose fibers, or of cellulose fibers. wood, or any other building block made of vegetable fibers. This mixture thus makes it possible to maintain product homogeneity that is similar and identical to the building block, and this in order to avoid a different reaction of the materials as a function of a temperature change or variation that can bring about an expansion. In a particular variant, a dry mix of fine-particle wood fibers of the sawdust and cement type, then moistened with water, makes it possible to produce an adhesive mortar for the assembly of wood fiber building blocks. , or of cellulose fibers, or any other building block made of vegetable fibers. This mixture thus makes it possible to maintain product homogeneity that is similar and identical to the building block, and this in order to avoid a different reaction of the materials as a function of a temperature change or variation that can bring about an expansion. According to another variant, a dry mixture of fine-particle vegetable fibers, for example of hemp, linen, etc., and cement, then moistened with water, makes it possible to produce an adhesive mortar for the assembly building blocks of vegetable fibers, or of cellulose fibers, or any other building block made of wood fibers. This mixture thus makes it possible to maintain product homogeneity that is similar and identical to the building block, and this in order to avoid a different reaction of the materials as a function of a temperature change or variation that can bring about an expansion.

It is preferable to respect the same proportions of component in the dosages of the adhesive mortar mixture as those of the building blocks and this in order to have a homogeneity in the assembly between the building blocks and the adhesive mortar. It is also possible to provide a composition of adhesive mortar with a mixture of different vegetable fibers, for example of hemp, linen, wood, cellulose, etc., and cement, then moistened with water. In addition, various adjuvants can be added to the various mixtures proposed, for the acceleration or retardation of the setting of the binder, the coloring of the material, its water-repellency, its fireproofing, the fungicidal or insecticidal treatment, the fluidification of the mixture, for a faster curing or to obtain a high performance mix.

Claims (4)

1 - Bloc agglomerated compressed cellulose fibers, characterized in that it comprises cellulose fibers and a hydraulic binder and in that it is obtained by a process in which an initial mixture comprising cellulose fibers and a hydraulic binder is maintained under pressure throughout the setting time of the binder, the cellulose fibers accounting for at least 65%, preferably about 65% to 95%, of the total volume of the initial dry matter mixture. 2 - Block of compressed agglomerated cellulose fibers, characterized in that it comprises cellulose fibers and a hydraulic binder, in that it is obtained by compression of an initial mixture comprising at least 65% of cellulose fibers, in volume of dry matter, and in that it has a density greater than about 500 kg / m3. 3 - Block agglomerated cellulose fibers according to claim 1 or 2, characterized in that it has a punching compressive strength greater than 0.5 mPa. 4 û Block of agglomerated cellulose fibers according to one of claims 1 to 3, characterized in that the cellulose fibers come from sludge or paste obtained after treatment of the old paper; new pulp; cellulose wadding for fabrics, optionally mixed with vegetable fibers, more preferably sludge or paste obtained after treatment of old paper made by the paper industry. Agglomerated cellulose fiber block according to one of Claims 1 to 4, characterized in that the binder is based on cement. 6 - agglomerated cellulose fiber block according to one of claims 1 to 4, characterized in that the binder is based on plaster. Agglomerated cellulose fiber block according to one of Claims 1 to 4, characterized in that the binder is based on lime. 8 - agglomerated cellulose fiber block according to one of claims 1 to 7, characterized in that it is produced from a mixture comprising, for a total of 100% representing the volume of the dry matter, 65 about 95% of cellulose fibers and about 5% to about 35% of hydraulic binder, and 10% to 30% of the total volume of dry matter. 9 - agglomerated cellulose fiber block according to one of claims 1 to 7, characterized in that it is produced from a mixture comprising, for a total of 100% representing the volume of the dry matter, 40 about 90% cellulose fiber, about 5% to 35% vegetable fiber, and about 5% to 25% hydraulic binder, and 10% to 30% water of the total volume of the dry matter. Agglomerated cellulose fiber block according to one of Claims 1 to 9, characterized in that the mixture also contains one or more adjuvants for coloring, accelerating or retarding binding of the binder, and water repellency. , fireproofing, fungicidal or insecticidal treatment, fluidification of the mixture, faster curing or to obtain a high performance mixture. 11 û Block of agglomerated cellulose fibers according to one of claims 1 to 10, characterized in that the mixture further contains reinforcing fibers of the agglomerated block. 12 - agglomerated cellulose fiber block according to one of claims 1 to 11, characterized in that it has a density greater than about 500 kg / m3, preferably greater than about 800 kg / m3. 13 - Process for preparing an agglomerated cellulose fiber block comprising the steps of forming or pouring into a mold a mixture comprising dried crushed cellulose fibers and a hydraulic bond hydrated with water, the fibers of cellulose representing at least 65%, preferably from 65% to about 95%, of the total volume of the dry matter of the initial mixture, then to apply and maintain the mixture under pressure throughout the setting time of the binder. 14 - Use of a block of cellulose fibers according to one of claims 1 to 12 as a construction element in the field of building. ~. ~ 15 - adhesive mortar fiber cellulose, characterized in that it comprises cellulose fibers and a hydraulic binder, the cellulose fibers representing at least 65% of the dry matter volume of the initial mixture, el: in that it is obtained by the dry blending of the cellulose fibers and the hydraulic binder and then moistened with water. 16. A fiber adhesive mortar according to claim 15, characterized in that it comprises different vegetable fibers mixed together. for example of the hemp, linen, wood and / or cellulose type, and in that it is obtained by dry blending the fine-particle vegetable fibers and the hydraulic binder and then moistened with water. 17- fiber adhesive mortar according to one of claims 15 to 16, characterized in that the binder is based on cement. 18 - fiber adhesive mortar according to one of claims 15 to 16, characterized in that the binder is based on lime. 19 - fiber adhesive mortar according to one of claims 15 to 16, characterized in that the binder is based on plaster. 20 - A fiber adhesive mortar according to one of claims 15 to 19, characterized in that the mixture also contains one or more additives for coloring, accelerating or retarding the setting of the binder, water repellency, fireproofing, fungicidal or insecticidal treatment, fluidification of the mixture, faster hardening or to obtain a high performance mixture.