EP2204483A2 - Mix of cellulose wadding and plant and animal fibres, manufacturing method and thermal insulating material - Google Patents

Abstract

The bulk material comprises a stabilized mixture of absorbent cellulose cotton and vegetable or animal fibers, flame retardant additives, and bactericidal-, antifungal- and/or insecticidal agent. The cellulose cotton is present in the form of small particles having an average size of lower than 2 mm. The weight ratio of cellulose cotton is 1/2, with respect to the total weight ratio of the cotton and fibers. The vegetable or animal fibers have an average length of 3-6 cm. The length of the mini-fibers of cellulose cotton is lower than 2 mm. The bulk material comprises a stabilized mixture of absorbent cellulose cotton and vegetable or animal fibers, flame retardant additives, and bactericidal-, antifungal- and/or insecticidal agent. The cellulose cotton is present in the form of small particles having an average size of lower than 2 mm. The weight ratio of cellulose cotton is 1/2, with respect to the total weight ratio of the cotton and fibers. The vegetable or animal fibers have an average length of 3-6 cm. The length of the mini-fibers of cellulose cotton is lower than 2 mm. The material has a density of 20-120 kg/m 3>, a thermal conductivity of 0.040 W/Km and a phase time of 10 hours, and is mixed with a binder consisting of molten synthetic fibers based on polyester coated with polyethylene or polypropylene, which is melted at a temperature lower than that of the polyester, where the weight ratio of the binder is 18-25% compared to the total weight of the material. An independent claim is included for a process for fabricating a bulk material.

Description

The present invention relates to a new thermal and sound insulating material and its manufacturing process. This material according to the invention is more particularly intended for the thermal and sound insulation of individual houses, industrial buildings, residential and collective.

This material consists of a mixture of cellulose wadding and plant fibers or animal fibers in variable proportions and has thermal performance greater than those commonly used insulants based on mineral fibers or natural insulation mono product of plant or animal fibers or cellulose wadding.

Mineral fibers such as glass wool and rock wool are well known as thermal insulating material, or even phonic. Similarly, the thermal and acoustic insulating properties of wool materials of vegetable and animal fibers are known, as the case may be, refined by fraying. Some mineral insulators collapse and settle over time because of a separation of fibers and their binders, changing the value of insulation throughout their lives. Insulants based on animal and vegetable wool do not know this phenomenon because of the resilience and elasticity of their fibers. In addition, plant and / or animal fibers are biodegradable and are therefore not bio-persistent in the body.

Vegetable and animal fibers may be applied in bulk, in particular by blowing, or manufactured in the form of relatively soft nonwoven webs, in rolls or in panels when they are hot-mixed with binders, especially based on thermo-fusible synthetic fibers. such as polyester-based fibers.

Similarly, cellulose wadding, a fluffy material from the sorting and recycling of newspaper or printing papers, provides excellent thermal and sound insulation.

• une faible conductivité thermique, et
• un temps de déphasage thermique élevé. Le temps de déphasage d'un matériau est le temps que met ledit matériau à atteindre son régime stationnaire lorsqu'on lui applique un gradient de température, c'est-à-dire la capacité du matériau à ralentir les changements de température.

The thermal insulation properties of a material are related to:

• low thermal conductivity, and
• a high thermal phase shift time. The phase shift time of a material is the time that said material reaches its steady state when a temperature gradient is applied, ie the ability of the material to slow down temperature changes.

The very good thermal and sound insulation properties of cellulose wadding and vegetable or animal fibers are illustrated by a coefficient of thermal conductivity lower than that of insulating mineral wools such as wools of glass and rockwool, and especially a phase shift time more than double that of insulating mineral wools.

Another essential advantage of cellulose wadding is its relatively low cost compared with insulating wools of mineral, vegetable or animal fibers.

However, the disadvantage of cellulose wadding is that it is applied in bulk by blowing itself in the course of time, which affects its insulating properties insofar as the amount of air trapped for a given volume is found relatively small. Furthermore, the cellulose wadding can be formulated in the form of a panel or sheet only under unsatisfactory rigidity conditions. Indeed, because of its friable structure, it is possible to obtain only relatively rigid compact panels of relatively high density especially greater than 60 kg / m3, with high proportions of binder which affects their insulating properties. These panels, because of their rigidity which makes them relatively friable and brittle, have unsatisfactory mechanical properties when used for lack of flexibility.

It has been proposed US 5,910,367 , a bulk mixture of cellulose wadding particles of size up to 10 mm, with cotton fibers in a weight proportion of less than 40%, to improve the thermal insulation properties of cellulose wadding. However, this a mixture of cellulose wadding and cotton fiber described in US 5,910,367 has insufficient mechanical cohesion properties to formulate it as a nonwoven web to make panels.

An object of the present invention is to provide a new, improved insulating material, in particular which combines the advantages of insulants based on plant or animal fibers in terms of the thermal insulation property and the mechanical property of cohesion and flexibility of the products in question. tablecloth, while being less expensive than an insulator based on vegetable or animal fibers.

To do this, the present invention provides a material consisting of a stabilized mixture of cellulose wadding and plant or animal fibers wherein the cellulose wadding is in the form of small particles of average size less than 5 mm, preferably lower at 2 mm, retained in an entanglement of said plant or animal fibers, the length of said plant or animal fibers being greater than said average size of said cellulose wadding particles, preferably greater than or equal to 1.5 cm, the weight ratio of cellulose wadding, in relation to the total of the cellulose wadding and said vegetable or animal fibers, being between 1/3 and 2/3.

The term "stabilized mixture" is understood here to mean that the cellulose wadding remains retained by said fibers in the form of small particles, without the use of a binder.

The inventors have discovered that this mixture has a synergy in terms of thermal conductivity with identical density relative to starting materials exclusively based on cellulose wadding as an insulating material on the one hand or exclusively based on vegetable or animal fibers. on the other hand, while reducing the cost compared to a material based exclusively on vegetable or animal fibers.

The thermal performance of an insulation is a function of its ability to trap air and block its circulation. This capacity of imprisonment is related to the fineness of the fibers which one obtains if necessary by successive fraying. Necessarily due to the friable quality of the cellulose wadding, part of it is in the form of finer particles invisible to the naked eye trapped in the interstices of intermingling of said fibers. The inventors formulate the hypothesis that, by intermingling with plant or animal fibers, particles of celluloses which have a size smaller than that of vegetable fibers, or animal fibers, enter the interstices of vegetable or animal fibers intermingled so that cellulose wadding improves the ability of said fibers to stabilize the air they contain and therefore make it a more efficient insulation.

By reducing the size of the cellulose wadding particles compared to that of the particles of the document US 5,910,367 , it promotes a better homogenization of the mixture and thus a greater penetration of cellulose wadding particles in the interstices of the intermingled vegetable or animal fibers, so that the air is trapped more securely and trapped inside the interstices of intermingled plant or animal fibers, which leads to improving the thermal insulation properties provided that the amount of trapped air is sufficient, which is the case if a sufficiently high weight proportion of vegetable or animal fibers is maintained in The mixture.

On the other hand, the phase shift time of the mixing material is proportional to the phase shift times of the materials constituting the mixture in proportion to the respective weight proportions of the two constituents, ie a phase shift time of the mixture greater than 10 hours. Thus, when the phase shift time of the plant or animal fibers is greater than that of the cellulose wadding, in particular with flax fibers, the mixture according to the present invention has a longer phase shift time.

Last but not least, a mixing material according to the invention has, by virtue of its greater homogeneity of mixing, improved mechanical cohesion properties and, in particular, a resistance to settlement. improved. In fact, the reduction in the size of the cellulose wadding particles promotes the best filling of the interstices of the intermingled fibers and thus the cohesion of the mixture and reduces the settling phenomena of the mixture, which results in particular from the packing of the cellulose wadding particles. .

In addition, the increase in the proportion by weight of vegetable or animal fibers contributes to imparting greater elasticity to a mixture material according to the invention formulated in the form of a sheet.

Preferably, in order to obtain optimum mechanical cohesion properties in a material according to the invention, the weight ratio of cellulose wadding to total cellulose wadding and said vegetable or animal fibers is between 35% and 60%, preferably less than or equal to 50%, more preferably about 50%.

Furthermore, the reduction of the cellulose wadding content in the mixture according to the invention results in less loss of cellulose wadding during the mixing process, especially during manufacture in the form of a sheet, as described below.

Advantageously therefore, a mixing material according to the invention mixed with a binder can be used for the manufacture of manufactured products in sheet, such as rolls, panels or shells and whose mechanical properties of flexibility are comparable to those of the vegetable fiber webs. and animals and make the implementation easy to apply.

More preferably, in the mixing material according to the invention, said vegetable or animal fibers have an average length of less than 10 cm, preferably 3 to 6 cm, and the lengths of the mini fiber of cellulose wadding are less than 2 mm.

• les fibres de lin, coton, chanvre, coco, banane, palmier, bambou, yucca, maïs et fibres cellulosiques de bois, de préférence des fibres de lin ou coton, pour les fibres végétales, et
• les fibres de mouton, yack, et chèvre, de préférence des fibres de mouton, pour les fibres animales.

The vegetable or animal fibers may be chosen more particularly from:

• flax fibers, cotton, hemp, coconut, banana, palm, bamboo, yucca, maize and cellulosic wood fibers, preferably flax or cotton fibers, for vegetable fibers, and
• sheep, yak, and goat fibers, preferably sheep fibers, for animal fibers.

Advantageously, the plant or animal fibers are previously treated anti-fire, anti bacteria, antifungal and anti-insects, especially using a specific pre-treatment line as described in FR 2,886,948 on behalf of the applicants. Also the dry flame retardant treatment with boron salts and various adjuvants to improve the resistance to microorganisms, rodents and vermin of cellulose wadding are known. Therefore, advantageously, the material according to the invention further comprises flame retardant additives, such as boron salts or ammonium salts, and / or bactericidal, antifungal and / or insecticidal adjuvants and the like, such as based on iso thiazole or encapsulated essential oils having biocidal properties, such as encapsulated Neem oil (PRONEEM company - France).

A material according to the invention may be manufactured in the form of a sheet mixed with a binder consisting of hot melt synthetic fibers, preferably based on polyester, preferably further coated with polyethylene or hot melt polypropylene at a temperature lower than that of the polyester, in particular binder fibers in weight proportion of 15 to 30%, preferably 18 to 25%, relative to the total weight of the material.

The thermal performance of an insulator is related to its density. As density increases, the amount of stabilized air increases and the value of the thermal conductivity coefficient decreases. A cellulose fiber wadding material and fibers according to the invention makes it possible to obtain higher densities than those obtained with the vegetable or animal fibers separately.

More particularly, when it is in bulk flakes applied by blowing, the mixing material according to the invention then has a density of 10 to 40 kg / m3, preferably 15 to 30 kg / m3. The bulk material is, more particularly, applied by blowing on thicknesses of 10 to 30 cm, and the sheet material has a density of 20 to 120 kg / m 3, and more particularly, the thickness of the sheet material. is 2 to 20 cm.

Here is meant by "bulk applied by blowing", a quantity of material deposited by blowing into an open space, against a support such as a wall, as is the case, especially in roofs lost roof.

The present invention provides, more particularly, a thermal insulating material consisting of a said mixture of cellulose wadding and plant or animal fibers having a thermal conductivity less than 0.045 W / km, preferably less than 0.040 W / km, and a time phase shift greater than 10 hours.

Obtaining a mixture of cellulose wadding and plant or animal fibers homogeneous and stable in terms of mechanical strength represented a problem due to the friable nature of the cellulose wadding, this problem was solved by a specific mixing process.

In particular, obtaining a mixing material with particles with apparent flakes of cellulose as small as less than 5 mm was made possible only by the implementation of an original preparation process according to the present invention, according to which the cellulose wadding / plant or animal fiber mixture is refined and homogenized in two stages. Firstly, a first mixture of an intermingling of plant or animal fibers with particles of cellulose wadding of relatively large size, during which said particles are ground and the opening of said fibers is carried out on a first drum equipped with carding spikes. Then, the size of the cellulose wadding particles is reduced and homogenized to a final size of less than 5 mm, continuing their mixing with said fibers open on a drum equipped with tips or blades of smaller size, for stabilizing said small particles of cellulose wadding in a new intermingling of plant fibers.

1. a) on réalise le mélange de la ouate de cellulose et d'un entremêlement de dites fibres végétales ou animales, de préférence dans des proportions déterminées, en l'appliquant sur au moins un tambour cylindrique rotatif équipé sur sa surface externe de pointes cardeuses de dimension supérieure à 1 cm, de préférence de 2 à 5 cm, de préférence le tambour comportant une pluralité d'au moins 4 rangées longitudinales dans la direction axiale du tambour, de manière à ouvrir l'entremêlement de dites fibres et concomitamment broyer la ouate de cellulose en gros flocons de taille inhomogène avec une taille moyenne supérieure à 2 cm, de préférence de 2 à 5 cm, de préférence encore lesdites grandes pointes étant espacées dans lesdites rangées d'une distance de 2 à 5 cm, et
2. b) on affine et homogénéise le mélange obtenu à l'étape a) en l'appliquant sur au moins un tambour cylindrique rotatif équipé de pointes ou lames en dents de scie de plus petite taille, de préférence inférieure à 1 cm et en plus grand nombre de préférence régulièrement espacées sur toute la surface du tambour, de préférence à une distance les unes des autres inférieure à 10 mm, de préférence encore au moins deux dits tambours cylindriques rotatifs disposés successivement et équipés, respectivement, l'un de dites pointes de plus petite taille et l'autre de dites lames en dent de scie de plus taille.

More precisely, according to another aspect, the present invention indeed provides a method of manufacturing a bulk mixing material according to the invention, characterized in that the following steps are carried out in which:

1. a) the cellulose wadding is mixed with an intermingling of said plant or animal fibers, preferably in predetermined proportions, by applying it to at least one rotary cylindrical drum equipped on its external surface with carding spikes; dimension greater than 1 cm, preferably from 2 to 5 cm, preferably the drum having a plurality of at least 4 longitudinal rows in the axial direction of the drum, so as to open the intermingling of said fibers and concomitantly grind the wadding cellulose in large flakes of inhomogeneous size with an average size greater than 2 cm, preferably 2 to 5 cm, more preferably said large tips being spaced in said rows by a distance of 2 to 5 cm, and
2. b) the mixture obtained in step a) is refined and homogenized by applying it to at least one rotary cylindrical drum equipped with sawtooth tips or blades of smaller size, preferably less than 1 cm, and larger number preferably evenly spaced over the entire surface of the drum, preferably at a distance from each other less than 10 mm, more preferably at least two so-called rotary cylindrical drums arranged successively and equipped, respectively, one of said tips of smaller size and the other of so-called sawtooth blades of larger size.

This process makes it possible to limit the losses of cellulose wadding because the cellulose wadding would volatilize into powder and could no longer be stabilized by the fibers if it breaks up too quickly into dust or small flakes before the fibers are sufficiently open and refined. to retain said cellulose wadding particles. At the end of step a), a first inhomogeneous mixture is obtained with large lump or flakes of wadding of disparate sizes but already partially stabilized by a first opening of the plant or animal fibers.

At the end of stage b), the apparent flakes of cellulose have an average size of less than 5 mm, preferably less than 2 mm, and are retained in an entanglement of said plant or animal fibers, and said plant fibers or animals are sufficiently refined that is to say aerated or defibrillated so that mini fibers of cellulose wadding dust are retained in the interstices of said fibers.

Failure to implement a two-step mixing process, as described above, cellulose wadding particles smaller than 5 mm could not be stabilized in the mixture because they would volatilize if they were not retained between the fibers. To do this, the size reduction of said cellulose wadding particles, from larger particles, must be concomitant with the opening of the plant or animal fibers from said intermingling of plant or animal fibers.

Advantageously, the relative proportion of cellulose wadding, relative to the total of the cellulose wadding and said plant or animal fibers, in the final mixture product is less than at most 15%, preferably at most 10%, relative to the relative proportion of cellulose wadding relative to the total proportions of cellulose wadding and said plant or animal fiber in the starting materials, taken separately.

In other words, the losses of cellulose wadding are less than 15, preferably less than 10%. These losses are due to the volatilization of the cellulose wadding pulverized during the different steps of the process.

• la ouate de cellulose de départ présente une densité de 20 à 35 kg/m3 en application en vrac par soufflage, notamment sous forme de particules fibreuses de taille inférieure à 10 mm, et des longueurs moyennes de fibres inférieures à 5 mm, de préférence inférieures à 2 mm, et
• lesdites fibres végétales ou animales présentent une densité de 10 à 20 kg/m3 en application en vrac par soufflage, et des longueurs moyennes de fibres inférieures à 10 cm, de préférence de 3 à 6 cm.

More particularly, the starting materials have the following characteristics:

• the starting cellulose wadding has a density of 20 to 35 kg / m 3 in bulk application by blowing, in particular in the form of fibrous particles less than 10 mm in size, and average fiber lengths of less than 5 mm, preferably less than at 2 mm, and
• said plant or animal fibers have a density of 10 to 20 kg / m3 in bulk application by blowing, and average fiber lengths less than 10 cm, preferably 3 to 6 cm.

Advantageously, said fibers are treated by immersing them in a tank containing a solution of flame retardant, bactericidal, antifungal and / or insecticidal adjuvants in which said fibers are mechanically beaten and then dried before step a).

This beat treatment is advantageous for accelerating and improving the impregnation of said fibers by said adjuvants.

For the manufacture of a material according to the invention in the form of a non-woven sheet, is added in addition to the mixture of constituents, preferably from step a), thermally fusible synthetic binder fibers, preferably synthetic fibers. polyester base, more preferably polyester fibers coated with polyethylene or polypropylene, and a thermal and mechanical treatment is carried out to manufacture said mixture obtained after step b) in the form of a sheet of mixture of cellulose wadding and said fibers. nonwoven.

More particularly, said binder fibers or, preferably, only the outer coating of said binder fibers, has a melting temperature lower than the melting temperature of said plant or animal fibers and of said cellulose wadding and, where appropriate, lower at the melting temperature of the core portion of said binder fibers with respect to the melting temperature of the outer coating of said binder fibers. And, the mixture of said constituents is brought to said melting temperature of said binder fibers or, preferably, to the melting temperature of the outer coating said binder fibers, at which temperature, said plant or animal fibers and said cellulose wadding, especially by their flame retardant pretreatment, do not melt but are bonded together by said molten binder fibers or, preferably, only said coating externally melted said binder fibers.

• la figure 1 représente un schéma de l'installation de fabrication,
• la figure 2 représente une coupe longitudinale d'un compartiment de chargement 12, 13 ou 14, et
• la figure 3 représente une coupe longitudinale d'une effilocheuse 18 de la figure 1.

Other features and advantages of the invention will become apparent in the light of the detailed description which follows, with reference to the following figures, in which:

• the figure 1 represents a diagram of the manufacturing facility,
• the figure 2 represents a longitudinal section of a loading compartment 12, 13 or 14, and
• the figure 3 represents a longitudinal section of an effilocheuse 18 of the figure 1 .

Various mixtures of cellulose wadding were made on the one hand and flax, cotton or sheep fibers having the following characteristics on the other hand.

The cellulose wadding is packaged in compact form at densities of 50-100 kg / m 3, corresponding to a bulk density of the bulk material applied by blowing, in the form of fibrous particles smaller than 10 mm, more precisely of lower average size. at 5 mm, 24 kg / m3. Cellulose wadding came from CELLISOL (France) with a thermal coefficient of 0.042 W / m.K.

The different plant or animal fibers are characterized by their length and origin.

Flax fibers are derived from scutching the stem of the plant to obtain refined flax fibers, average lengths of 2 to 6 cm. The density of the flax fibers in their packaging bag is 50-100 kg / m3 but, once out of the bag, the bulk flax fibers applied by blowing have a density of 12 to 15 kg / m3.

The cotton used was derived from the recycling of clothing and contained small proportions of 15 to 20% of other types of fibers, for example synthetic fibers, also having fiber lengths of 2 to 6 cm and densities similar to those to flax fiber.

The sheep fibers are derived directly from the mowing of the animal and also have lengths similar to those of flax and cotton fibers. On the other hand, their density varied from 10 to 13 kg / m3.

• pour les fibres de lin à une densité de 25 kg/m3 de 0,045 W/m.K
• pour les fibres de coton à une densité de 25 kg/m3 de 0,038 W/m.K
• pour les fibres de laine de mouton à une densité de 25 kg/m3 de 0,042 W/m.K.

The thermal conductivity coefficients λ of the fibers applied by blowing were:

• for flax fiber at a density of 25 kg / m3 of 0.045 W / mK
• for cotton fibers at a density of 25 kg / m3 of 0.038 W / mK
• for sheep wool fibers at a density of 25 kg / m3 of 0.042 W / mK

In particular, ISO4 type blowers of ISOLFRANCE (France) are used.

• une ligne de traitement,
• une ligne de mélange avec pré ouvreuse-mélangeuse,
• une ou plusieurs effilocheuses en cascade,
• une nappeuse pour les produits manufacturés tels que les rouleaux, les panneaux ou les coquilles, et
• un système de conditionnement pour les produits en vrac.

The device for manufacturing the mixture of cellulose wadding and vegetable or animal fibers comprises the assembly of several machines arranged in the order given below:

• a treatment line,
• a mixing line with pre-open mixer-mixer,
• one or more cascades in cascade,
• a tableting machine for manufactured products such as rolls, panels or shells, and
• a packaging system for bulk products.

1. 1- le traitement - séchage des fibres animales ou végétales
2. 2- le mélange de ces fibres avec la ouate de cellulose
3. 3- l'effilochage du mélange obtenu à l'étape 2.

The production line comprises 3 main stages:

1. 1- treatment - drying of animal or vegetable fibers
2. 2- the mixture of these fibers with cellulose wadding
3. 3- fraying the mixture obtained in step 2.

The animal or vegetable fibers in bales of 120 to 300 kg are placed on a supply belt 1 which makes it possible to bring the animal or vegetable fibers into an opening loader 2 which will open the bales of fibers. At the exit of the loader opener 2, the fibers fall on a weighing belt 3. It is a conveyor belt mounted on electronic load cells connected to a controller that calibrates the mass of fibers.

When the predetermined mass of the fibers has been poured onto the weighing belt 3, the automaton stops the opening loader 2 and controls the displacement of the weighing belt 3 to transfer the fibers thus weighed onto a loading conveyor 3a which discharges the wool to the entrance to a treatment tunnel.

This treatment tunnel consists of two successive identical treatment modules 4 and 5, which contain rotating drums inside which said fibers and a treatment solution are introduced. The two processing modules are contiguous with each other and communicate with each other by admission and transfer means formed in the side flanges of the drums they contain. The intake and transfer means consist of an opening formed in the opposing flanges of the drums of the two modules.

Inside the drums of each treatment module 4 and 5 is fixed a fiber stirring means constituted by a helical wall welded to the inner cylindrical wall of the drum and extending in a secant direction to the cylindrical wall. This helical wall is such that when the drum of one of the processing modules is driven by its motor in rotation in one direction, the fibers are brewed inside the drum and, when the drum is rotated in the other In the sense, the fibers are expelled from the drum and transferred to the neighboring drum by the transfer means described above.

Thus, after having loaded the first module 4 with a first quantity of fibers and carried out a first treatment thereof with a processing solution, the control automaton 25 reverses the direction of rotation of the drum of the first module 4 which is empty. filling the second module 5 where the fibers undergo a second treatment in a treatment solution. The first module 4 emptied, it can again be filled with fibers by the loading carpet 3a.

In addition, pivoting beaters are also attached to the inner walls of the drum of each of the processing modules 4 and 5 to strike the fibers at each drum revolution against the walls thereof. This threshing of the fibers during rotation of the drum makes it possible to improve the penetration of the treatment solution into the fibers. The material will thus be beaten tens of times against the inner walls of the drum of each of the treatment modules 4 and 5.

At the end of the treatment cycle, the direction of rotation of the drum of the module 5 is reversed. The fibers are then poured into a hydraulic press 6 to be dewatered. The dewatering effluents of the treated fibers are then recycled to a tank 26 containing a treatment solution by a recovery circuit 27.

The treatment solution contains flame retardants, bactericides and fungicides. An aqueous treatment solution with 5 to 15% flame retardants, bactericides and fungicides is used.

The treatment time is variable depending on the treated fibers. Processing times vary from 30 seconds to 100 seconds for each module. That is to say a total duration of treatment varying between 60 and 200 seconds.

At the outlet of the hydraulic press 6, the material falls into a translator carriage 7 which will feed three dryers 8, 9 and 10 to hot air. In these dryers, the fibers undergo drying of a variable duration of 60 to 1500 seconds at a temperature between 100 ° C and 150 ° C depending on the material to be dried. During this drying, all the water remaining in the fibers after wringing in the press 6 is evaporated and only the treatment agents remain in the fibers.

Depending on the cycle time of each dryer 8, 9 and 10, the controller 25 directs the translator carriage 7 to an empty dryer as the treated fibers arrive from the press 6.

Each dryer, at the end of the cycle, reverses its direction of rotation to discharge, as in the treatment modules, the dried fibers on a conveyor belt 11 to the mixing plant (12, 13 and 14) of the fibers with the cellulose wadding.

In addition, this mixing plant comprises three identical compartments for loading materials 12, 13 and 14. Each of them comprises a feed belt 28 followed by a pointed apron 29 with a length greater than or equal to 2 cm. which makes it possible to hook the material and to transport it in the weighing module 30. The weighing module 30 makes it possible to quantify the masses of material to be mixed. These quantities are previously defined. They are a function of the percentage of each material in the final mixture. A percentage ranging from 45 to 70%, preferably approximately 60% for the starting cellulose wadding, and 60 to 30%, preferably 40% respectively, for said starting animal or vegetable fibers, will give, in the final product, considering the losses of cellulose wadding during the process, which are however less than 15% relative to the amount of initial cellulose, preferably less than 10%, a mixture of cellulose wadding and said fibers comprising 35% to 55, preferably about 50% cellulose wadding and, respectively, 45% to 65%, preferably about 50%, of animal or plant fibers.

The dried fibers are poured by the conveyor belt 11 onto the feed belt of the compartment 14.

The cellulose wadding is deposited on the carpet of the loading compartment 13. The material is hooked by the pointed apron which bring the material to the weighing module. When the predefined mass has been dumped into the weighing module, the machine stops the feed belt 28 and the spiked deck 29, and controls the opening of the weighing module 30 which pours the material on the conveyor belt 15. The controller moving the belt to the level of the weighing module of the load compartment 14.

When the predefined mass of fibers is poured into the weighing module of the compartment 14, in the same way as for the compartment 13, the automaton stops the feed belt 28 and the pointed apron 29 and orders the opening of the module 30. The animal or vegetable fibers are then poured onto the cellulose wadding already present on the conveyor belt 15.

A superposition of the cellulose wadding and vegetable or animal fibers is then obtained.

For the manufacture of sheet-milled products, synthetic fiber binders based on polyethylene and polypropylene may be added in the loading compartment 12. For example, polyester fibers of the company ROHTEX gmbh (Germany) of the type are used. 4559/7827, with an average length of about 50 mm, in a relative proportion of 18 to 25% relative to the total of the other components and said binder fibers, namely in total of cellulose wadding, vegetable fiber or animal and so-called binder fibers, it being understood that the relative proportion of wadding of cellulose and vegetable or animal fibers, relative to each other, remains within the above-mentioned ranges. These fibers are called bicomponent fibers because they are made of polyester core, but coated with polyethylene. Because the polyethylene has a melting temperature of 150 ° C, lower than that of the polyester of 180 ° C, during the heat treatment in the laminator, as described below, only the polyethylene melts, providing the binder function. with the vegetable or animal fibers to which the binder fibers are mixed. They are visible to the naked eye but are intertwined with plant or animal fibers.

We will then obtain a superposition of several layers composed of binders, cellulose wadding and plant or animal fibers, on the carpet 15.

The conveyor belt 15 feeds the materials to a preoperator, mixer 16 where the cellulose wadding and the fibers will undergo a first mixture by passing on a drum 16a with carding spikes length of about 2 cm. These tips are arranged in 5 axial rows on the surface of the drum 16a, without covering the entire surface of the drum.

This drum 16a carding spikes allows a first mixture of cellulose wadding with vegetable or animal fibers. A mixture is obtained in which the cellulose wadding flakes are of relatively large average size (2 to 5 cm) and intermixed with the vegetable or animal fibers in an inhomogeneous manner.

The first mixture is then conveyed to a loader 17 comprising a spiked apron which hooks the materials to deposit them on the feeding apron 31 of the fooler of the company LAROCHE (France), type CADETTE 1000 with two drums. The materials are driven and maintained across the width of the machine through the feeding trough 32 and the feed roller 31. The web of material is thus presented to the action of a drum with smaller carding spikes. 34. Said small points are from 5 mm to 10 mm long, spaced less than 1 cm apart from each other and covering the entire surface of the drum.

The mixture of fibers and cellulose wadding is then sucked by the lapper transmitter thanks to the depression created by a fan 38 through the perforated roll 35 on which the web of defibrated material is formed.

The sheet of material is delivered by the corrugated rollers 33 for feeding a next drum 37, equipped on its entire surface with small sawtooth blades less than 1 cm high, juxtaposed next to each other in staggered rows. .

Drums with small carding points and sawtooth blades 34, 37, allow a refining or defibration of the fibers and a homogeneous mixture of the cellulose wadding with these fibers. The particles of cellulose wadding, smaller than 5 mm, are trapped in the intermingling of plant or animal fibers.

The various drums 16a, 34 and 37 have a cylindrical shape of length about 1 m and diameter about 50 cm, with rotation speeds in action of the order of 1000 to 1500 revolutions / minute.

In the fray 18, the lost material is recycled by the carpet 41.

The overall hourly output of the plant described above is about 200 to 400 kg of manufactured mixture per hour.

The mixture thus obtained at the outlet of the shredder 18, on an exit apron 39, is poured onto an inverter mat 19 which feeds either a lapper 20 or a loose packaging machine 24.

For mixtures consisting of binders of cellulose wadding and of vegetable or animal fibers and intended for the manufacture of manufactured products, the inverter mat 19 feeds a tablecloth 20. This lapper makes it possible to manufacture mixing plies of different thicknesses (of 2 cm at 20 cm) and different densities (20 kg / m3 to 120 kg / m3). We know, in particular, tablecloths marketed by the company LAROCHE, under the reference pneumatic lapper. the laminator carries the mixture at a temperature equal to the melting temperature of the hot-melt binder fibers, the temperature at which the cellulose wadding and the vegetable or animal fibers do not melt, given their treatment with a flame retardant. A laminator is used to calibrate a mass of material and a thickness to give a density to the web of formed material. The web of formed material is then fed into an oven for the hot melt binders to melt and bind to the plant or animal fibers.

If the binder fibers have not been added to the loader 12, before mixing, it is still possible to mix them with the mixture of cellulose wadding and vegetable or animal fibers before introducing them or when they are introduced into the laminator , in the proportions mentioned above.

For bulk mixtures of cellulose wadding and plant or animal fibers, the inverter mat 19 supplies, via the belts 21 and 22, an opening loader 23 which feeds a press 24 that can package the mixture into bales of 2 kg to 20 kg, compacted in general at a density of 50 to 100 kg / m3.

• pour les applications en vrac par soufflage : les épaisseurs de mélange en vrac, une fois appliquées, peuvent varier de 10 cm à 30 cm, les densités variant de 14 à 30 kg/m3, les valeurs de λ (coefficient de conductivité thermique) variant entre 0,038 W/m.K, pour les densités les plus fortes, à 0,045 W/m.K, pour les densités les plus faibles, et
• pour les produits manufacturés en nappe: les épaisseurs de nappe varient de 2 à 20 cm, les densités variant de 20 à 120 kg/m3, et les valeurs de λ (coefficient de conductivité thermique) variant entre 0,036 W/m.K, pour les densités les plus fortes, à 0,040 W/m.K, pour les densités les plus faibles.

The densities of the mixtures obtained vary according to the modes of application:

• for loose bulk applications: loose bulk thicknesses, when applied, can vary from 10 cm to 30 cm, with densities ranging from 14 to 30 kg / m3, values of λ (coefficient of thermal conductivity) varying between 0.038 W / mK, for the highest densities, to 0.045 W / mK, for the lowest densities, and
• for flat products: web thicknesses range from 2 to 20 cm, densities vary from 20 to 120 kg / m3, and λ values (thermal conductivity coefficient) vary between 0.036 W / mK, for densities the strongest, at 0.040 W / mK, for the lowest densities.

Comparative measurements of the values of thermal conductivity coefficient were carried out with a thermal conductivity measuring device called conductimeter, according to the method of hot plate kept, brand LASERCOMP, type Lasercomp Fox 314 distributed by FONDIS (France) . <u> Comparative table of values of thermal conductivity coefficients </ u>: Coefficient of thermal conductivity CELLULOSE (at a density of 24 kg / m ³ ) LIN (at a density of 25 kg / m ³ ) LIN + CELLULOSE (at a density of 25 kg / m ³ ) λ (W / m .K) 0,042 0,045 0,039

In the table above, the densities are given for loose bulk applications, and the mixture of cellulose wadding and flax fiber corresponds to a proportion of about 50/50 between the two components.

It can be seen that the mixing material according to the invention has a synergy, in terms of thermal conductivity, with respect to these constituent products taken separately, since this is lower than that of each of these constituents used under the same conditions. of density.

As regards the mechanical properties, for the panels, the flexibility decreases when the percentage of cellulose wadding increases and vice versa. The vegetable or animal fibers make it possible to limit the effect of stiffness of the cellulose even when the percentages of cellulose wadding increase in the mixture. The wool fibers of sheep, by their resilience, gives a better elasticity to the mixture than the flax fibers. "Elasticity" is understood here to mean that the product returns to its original shape after deformation. This better elasticity results in a better resistance to settlement. Cotton fibers because of their flexibility provides greater flexibility to the mixture than flax fibers also. The term "flexibility" is understood here to mean that the product can deform, in particular by folding, without breaking.

Claims (15)

Material consisting of a stabilized mixture of cellulose wadding and vegetable or animal fibers in which the cellulose wadding is in the form of small particles of average size less than 5 mm, preferably less than 2 mm, retained in an intermingling of said vegetable or animal fibers, the length of said plant or animal fibers being greater than said average size of said cellulose wadding particles, preferably greater than or equal to 1.5 cm, the weight ratio of cellulose wadding, relative to the total of the cellulose wadding and said vegetable or animal fibers being between 1/3 and 2/3. Material according to Claim 1, characterized in that the weight ratio of cellulose wadding, relative to the total of the cellulose wadding and of said vegetable or animal fibers, is between 35% and 60%, preferably less than or equal to 50%. %. Material according to claim 2, characterized in that said weight ratio of cellulose wadding to total cellulose wadding and said vegetable or animal fibers is about 50%. Material according to one of claims 1 to 3, characterized in that said plant or animal fibers have an average length of less than 10 cm, preferably 3 to 6 cm, and the lengths of the mini fiber of cellulose wadding are less than 2mm. Material according to one of Claims 1 to 4, characterized in that the vegetable or animal fibers are chosen from: - for vegetable fibers: flax fiber, cotton, hemp, coconut, banana, palm, bamboo, yucca, maize and cellulosic wood fibers, and - for animal fibers: sheep, yak and goat fibers. Bulk material according to one of Claims 1 to 5, characterized in that it is in flake with a density of 10 to 40 kg / m3, preferably from 15 to 30 kg / m3, in bulk application by blowing. Sheet material obtained from a material according to one of claims 1 to 6, mixed with a binder consisting of hot melt synthetic fibers, preferably based on polyester, preferably further coated with polyethylene or polypropylene hot melt at a temperature less than that of the polyester, in particular binder fibers in a weight proportion of 15 to 30%, preferably 18 to 25%, relative to the total weight of the material. Sheet material according to Claim 7, characterized in that it has a density of 20 to 120 kg / m3. Thermal insulating material according to one of claims 1 to 8, characterized in that it has a thermal conductivity less than 0.045 W / Km, preferably less than 0.040 W / Km, and a phase shift time greater than 10 hours. Process for producing a mixing material according to one of Claims 1 to 6, characterized in that the following steps are carried out in which: a) the mixture (12-16) of the cellulose wadding and an entanglement of said plant or animal fibers, preferably in predetermined proportions, is produced by applying it to at least one rotary cylindrical drum (16a) equipped with on its outer surface of carding tips of size greater than 1 cm, preferably 2 to 5 cm, preferably the drum having a plurality of at least 4 longitudinal rows in the axial direction of the drum, so as to open the intermingling of said fibers and concomitantly grinding cellulose wadding in large flakes of inhomogeneous sizes with an average size greater than 2 cm, preferably 2 to 5 cm, and b) the mixture (18) obtained in step a) is refined and homogenized by applying it to at least one rotary cylindrical drum (34, 37) equipped with smaller sawtooth points or blades, preferably less than 1 cm and more preferably evenly spaced over the entire surface of the drum, preferably at a distance from each other less than 10 mm, more preferably at least two so-called rotary cylindrical drums arranged successively and equipped, respectively , one of said tips (34) of smaller size and the other said saw blades (37) of larger size. Process according to Claim 10, characterized in that the relative proportion of cellulose wadding, relative to the total of the cellulose wadding and said vegetable or animal fibers, in the final mixture product is not more than 15%, preferably at most 10%, relative to the relative proportion of cellulose wadding relative to the total proportions of cellulose wadding and said vegetable or animal fibers in the starting materials, taken separately. Manufacturing process according to claim 10 or 11,
characterized in that the starting cellulose wadding has a density of 20 to 35 kg / m 3 in bulk application by blowing, and average fiber lengths of less than 5 mm, preferably less than 2 mm, and said plant or animal fibers have a density of 10 to 20 kg / m 3 in bulk application by blowing, and average fiber lengths of less than 10 cm, preferably 3 to 6 cm. Manufacturing method according to one of claims 10 to 12, characterized in that said fibers are treated by immersing them (6) in a tank containing a solution of flame retardant, bactericidal, antifungal and / or insecticidal adjuvants in which said fibers are mechanically beaten and then dried (8, 9, 10) before step a). Production method according to Claim 13, characterized in that, in the mixture, preferably in step a), synthetic hot melt binder fibers, preferably polyester-based fibers, preferably polyester fibers coated with polyethylene or polypropylene, and heat treatment is carried out and mechanical means for producing said mixture obtained after step b) in the form of a sheet of a mixture of cellulose wadding and said nonwoven fibers. Manufacturing method according to claim 14, characterized in that said binder fibers or, preferably, only the outer coating of said binder fibers has a melting point lower than the melting temperature of said plant or animal fibers and said wadding. cellulose and, where appropriate, lower than the melting temperature of the core portion of said binder fibers with respect to the melting temperature of the outer coating of said binder fibers, the mixture of said components being brought to said melting temperature of said binder fibers or, preferably, the melting temperature of the outer coating of said binder fibers, at which temperature, said plant or animal fibers and said cellulose wadding, in particular by their flame retardant pre-treatment, do not melt but are bonded between they by said melted binder fibers or only said coating ex melted dye of said binder fibers.

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