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EP0323292B1 - Process for coating fibres and its use in the production of composite materials - Google Patents

Process for coating fibres and its use in the production of composite materials Download PDF

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Publication number
EP0323292B1
EP0323292B1 EP88403094A EP88403094A EP0323292B1 EP 0323292 B1 EP0323292 B1 EP 0323292B1 EP 88403094 A EP88403094 A EP 88403094A EP 88403094 A EP88403094 A EP 88403094A EP 0323292 B1 EP0323292 B1 EP 0323292B1
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EP
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Prior art keywords
reinforcing elements
composite materials
conductive
electrodes
constituted
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EP88403094A
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German (de)
French (fr)
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EP0323292A1 (en
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Michel Berger
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Pradom Ltd
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Pradom Ltd
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    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C24/00—Coating starting from inorganic powder

Definitions

  • the present invention relates to a fiber coating process and its applications to the production of composite materials.
  • the electric currents used - the same as those used in the present invention - have for DC currents a voltage of 50,000 and 150,000 V and for AC currents a frequency between 50 and 1,000 Hz (preferably between 200 and 500 Hz) and a voltage between 10,000 and 30,000 V.
  • DC currents a voltage of 50,000 and 150,000 V
  • AC currents a frequency between 50 and 1,000 Hz (preferably between 200 and 500 Hz) and a voltage between 10,000 and 30,000 V.
  • a reinforcing element consisting of the initial reinforcing element, the surface of which has been coated with a thin, very adherent layer of the conductive or semiconductor powder material.
  • This new reinforcement element obviously has different surface properties from those of the initial reinforcement material and can therefore be used either to improve the properties of composite materials comprising said initial reinforcement element, or to produce composite materials by new combination of this new element of reinforcement with certain matrices.
  • the reinforcing elements which can be coated are very numerous, for example elements made of glass, aromatic polyamide, boron, carbon, silicon carbide, linen, hemp and more generally any original material. vegetable (cellulosic materials for example).
  • the coating process is particularly interesting in the case of materials of plant origin (cellulosic materials, flax, hemp, jute, etc.). Obviously, the operating conditions of the process making it possible to obtain a suitable coating of these various products will depend on said products; said conditions will be indicated below.
  • These reinforcing elements can have very diverse shapes, but most often they are in the form of more or less oriented fibers, flock or pulp.
  • the product used to make the coating consists of a powder of a conductive or semiconductor material or a mixture of powders of these materials; among the usable powders, there may be mentioned, for example, carbon, graphite, magnesium oxide, silver oxide, copper oxide or bromide, zinc oxide, titanium oxide, etc .; all these powders seem to be characterized by a relatively high electrical potential compared to other powders having a low or zero electrical potential.
  • usable conductive or semiconductor materials as materials whose resistivity, in volume, is less than 1010ohm / cm3.
  • the method used consists in spraying the powders on the reinforcing elements while these are subjected to the electrostatic field produced by two electrodes as indicated above.
  • a temperature above ambient temperature for example, from 25 to 60 ° C.
  • the method must be adapted in particular to the reinforcing elements used; the parameters that are varied are, in addition to the potential applied to the electrodes, the spacing of said electrodes and the duration of the treatment.
  • these elements will be subjected to the field produced by a direct current of approximately 100,000 V applied to electrodes 10 mm apart, the duration of application being approximately 10 min. If aromatic amide reinforcing elements are used, the potential of 100,000 V can be applied to electrodes spaced 7 mm apart and the application time will be approximately 5 min.
  • the difference between the electrodes will be all the greater as the reinforcing elements are more conductive; as a specific example, the treatment of glass reinforcing elements will advantageously be done by applying a potential of 15 to 30,000 V between two electrodes about 20 mm apart; the duration of application being approximately 3 to 5 min.
  • the etching phenomenon undergone by the reinforcing elements subjected to an electric field produced by an alternating current is definitive while the swelling phenomenon undergone by the reinforcing elements subjected to an electric field produced by a direct current is transient and of variable duration depending on the nature of said elements ranging for example from 2 to 3 min for glass to about 30 min for aromatic polyamides.
  • the coated reinforcing elements according to the invention can be used in very different dies to produce composite materials.
  • Virtually any known organic matrix conventionally used for the production of composite materials can be used.
  • As usable matrix mention may be made of epoxy resins, organic-inorganic resins, thermoplastics, ceramics and products with hydraulic setting or poor organic resins.
  • the coated reinforcing elements could, as a result, acquire an interesting compatibility with either materials with hydraulic setting, or with materials made of a poor inorganic resin ( glue or binder based on silica) loaded with suitable metal oxide (alumina for example).
  • glue or binder based on silica glue or binder based on silica loaded with suitable metal oxide (alumina for example).
  • Polydirectionally oriented jute fibers are heated to around 40 ° C and deposited between two electrodes powered by a direct current of 100,000 V. After a period of the order of 2 to 3 min, it is sprayed into the space between said electrodes a fine graphite powder and the current is maintained for approximately 2 min.
  • the jute fibers have been coated with a thin layer (of the order of 2 to 4 ⁇ m) of graphite.
  • the same electrodes were then supplied with an alternating current of 25,000 V for a period of 3 min; then powdered graphite is injected between said electrodes, and a direct current of 50,000 V is applied for 2 min.
  • Swollen glass fibers are collected coated with a layer of approximately 3 ⁇ m of graphite.
  • Cellulosic fibers in the form of a light flock are placed between two electrodes supplied by an alternating current of 20,000 V; a very fine powder of copper oxide is introduced into the space between these electrodes and the current is maintained for 3 min.
  • Cellulose fibers are collected coated with a very adherent thin layer (approximately 3 ⁇ m), of copper oxide.
  • the fibers coated with graphite obtained in Example 1 were used and these coated fibers were introduced between two electrodes supplied with an alternating electric current of 30,000 V. After 5 min of treatment, it was found that the fibers coated had been superficially etched.
  • coated fibers according to the invention are capable of undergoing, like the fibers described in the previous patents, phenomena of swelling, etching and possibly of surface oxidation when they are placed between electrodes supplied by a field. high voltage produced by direct and / or alternating current.
  • the fibers obtained according to Example 1 were placed in a mold having the shape of the desired finished object (plate for example); a sufficient quantity has been poured into this mold to fill the mold with a mixture of cement, water (mixing water) and a binder.
  • the hydraulic setting of the cement is allowed to take place and a plate is demolded having properties at least equal to those of known fiber cement plates.
  • the same experiment was carried out by replacing the cement with plaster and we obtained a very resistant plasterboard; to obtain a very resistant plasterboard according to the present invention of white color, use will be made, for example, of a reinforcing element constituted by jute fibers coated with titanium oxide.

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Chemical Or Physical Treatment Of Fibers (AREA)
  • Reinforced Plastic Materials (AREA)
  • Curing Cements, Concrete, And Artificial Stone (AREA)
  • Other Surface Treatments For Metallic Materials (AREA)
  • Compositions Of Macromolecular Compounds (AREA)
  • Inorganic Fibers (AREA)
  • Treatments For Attaching Organic Compounds To Fibrous Goods (AREA)

Abstract

Process for coating reinforcing members which are preferably in fibre form, characterised in that the said material is treated, between two electrodes, by the field obtained by means of a direct electrical current with a voltage of between 50 and 150,000 V and/or by means of an alternating electrical current with a frequency of between 50 and 1000 Hz and with a voltage of between 10,000 and 30,000 V and in that the said member is brought into contact with a powder of a conductive or semiconductive material.

Description

La présente invention concerne un procédé de revêtement de fibres et ses applications à la réalisation de matériaux composites.The present invention relates to a fiber coating process and its applications to the production of composite materials.

On sait réaliser des matériaux composites constitués par un élément de renforcement (fibre par exemple) et une matrice dans laquelle ledit élément de renforcement est noyé. On sait également que les propriétés des matériaux composites obtenus dépendent fortemen non seulement de la nature et des propriétés des matériaux qui les composent mais également des possibilités d'accrochage (propriétés interfaciales) entre la matrice et l'élément de renforcement. Un certain nombre de recherches se sont donc orientées vers la modification des propriétés superficielles de l'élément de renforcement pour rendre celui-ci compatible (ou plus accrocheur) avec la matrice.We know how to make composite materials constituted by a reinforcing element (fiber for example) and a matrix in which said reinforcing element is embedded. It is also known that the properties of the composite materials obtained strongly depend not only on the nature and properties of the materials which compose them but also on the possibilities of attachment (interfacial properties) between the matrix and the reinforcing element. A certain number of researches are therefore directed towards the modification of the surface properties of the reinforcing element to make it compatible (or more catchy) with the matrix.

Dans le cadre de ces recherches on a déjà décrit un procédé dans lequel les éléments de renforcement (fibres) étaient soumis, par passage entre deux électrodes, à des champs électrostatiques produits par utilisation de courants électriques continus et/ou alternatifs sous haute tension. On a indiqué que le champ électrostatique produit à partir d'un courant continu provoquait essentiellement un gonflement des éléments de renforcement et que le champ électrostatique, produit à partir d'un courant alternatif, provoquait un mordançage de la surface des éléments de renforcement et éventuellement une oxydation partielle de ladite surface. On rappelle que les courants électriques utilisés - les mêmes que ceux employés dans la présente invention - ont pour les courants continus une tension de 50 000 et 150 000 V et pour les courants alternatifs une fréquence comprise entre 50 et 1 000 Hz (de préférence entre 200 et 500 Hz) et une tension comprise entre 10 000 et 30 000 V. Ces propriétés des champs électrostatiques entraînent une modification de l'accrochage entre l'élément de renforcement et la matrice et, par conséquent, une modification (généralement une amélioration) des propriétés du matériau composite obtenu.In the context of this research, a process has already been described in which the reinforcing elements (fibers) were subjected, by passage between two electrodes, to electrostatic fields produced by the use of direct and / or alternating electric currents under high voltage. It has been reported that the electrostatic field produced from direct current essentially causes swelling of the reinforcing elements and that the electrostatic field produced from alternating current causes etching of the surface of the reinforcing elements and possibly partial oxidation of said surface. It will be recalled that the electric currents used - the same as those used in the present invention - have for DC currents a voltage of 50,000 and 150,000 V and for AC currents a frequency between 50 and 1,000 Hz (preferably between 200 and 500 Hz) and a voltage between 10,000 and 30,000 V. These properties of the electrostatic fields cause a modification of the bonding between the reinforcing element and the matrix and, consequently, a modification (generally an improvement) of the properties of the composite material obtained.

Il a été trouvé maintenant que ce même traitement d'éléments de renforcement par des champs électrostatiques produits par utilisation de courants électriques continus et/ou alternatifs permettait de revêtir lesdits éléments de renforcement à l'aide d'une poudre de matériau conducteur ou semi-conducteur.It has now been found that this same treatment of reinforcing elements with electrostatic fields produced by the use of direct and / or alternating electric currents makes it possible to coat said reinforcing elements with a powder of conductive or semi-material. driver.

On obtient ainsi, conformément au procédé défini à la revendication 1, un élément de renforcement constitué de l'élément de renforcement initial dont la surface a été revêtue d'une couche mince très adhérente du matériau en poudre conducteur ou semi-conducteur.There is thus obtained, in accordance with the method defined in claim 1, a reinforcing element consisting of the initial reinforcing element, the surface of which has been coated with a thin, very adherent layer of the conductive or semiconductor powder material.

Ce nouvel élément de renforcement possède bien évidemment des propriétés de surface différentes de celles du matériau de renforcement initial et peut donc être utilisé soit pour améliorer les propriétés de matériaux composites comportant ledit élément de renforcement initial, soit pour réaliser des matériaux composites par combinaison nouvelle de ce nouvel élément de renforcement avec certaines matrices.This new reinforcement element obviously has different surface properties from those of the initial reinforcement material and can therefore be used either to improve the properties of composite materials comprising said initial reinforcement element, or to produce composite materials by new combination of this new element of reinforcement with certain matrices.

Les éléments de renforcement que l'on peut revêtir sont très nombreux, par exemple des éléments en verre, en polyamide aromatique, en bore, en carbone, en carbure de silicium, en lin, en chanvre et plus généralement en tout matériau d'origine végétale (matériaux cellulosiques par exemple). Le procédé de revêtement est spécialement intéressant dans le cas de matériaux d'origine végétale (matériaux cellulosiques, lin, chanvre, jute, etc). Bien évidemment, les conditions opératoires du procédé permettant d'obtenir un revêtement convenable de ces divers produits vont dépendre desdits produits ; on indiquera ci-après lesdites conditions.The reinforcing elements which can be coated are very numerous, for example elements made of glass, aromatic polyamide, boron, carbon, silicon carbide, linen, hemp and more generally any original material. vegetable (cellulosic materials for example). The coating process is particularly interesting in the case of materials of plant origin (cellulosic materials, flax, hemp, jute, etc.). Obviously, the operating conditions of the process making it possible to obtain a suitable coating of these various products will depend on said products; said conditions will be indicated below.

Ces éléments de renforcement peuvent avoir des formes très diverses, mais le plus souvent ils se présentent sous forme de fibres plus ou moins orientées, de bourre ou de pulpe.These reinforcing elements can have very diverse shapes, but most often they are in the form of more or less oriented fibers, flock or pulp.

Le produit utilisé pour réaliser le revêtement est constitué par une poudre d'un matériau conducteur ou semi-conducteur ou un mélange de poudres de ces matériaux ; parmi les poudres utilisables, on citera, par exemple, le carbone, le graphite, l'oxyde de magnésium, l'oxyde d'argent, l'oxyde ou le bromure de cuivre, l'oxyde de zinc, l'oxyde de titane...; toutes ces poudres semblent caractérisées par un potentiel électrique relativement élevé par rapport à d'autres poudres présentant un potentiel électrique faible ou nul. On peut définir les matériaux conducteurs ou semi-conducteurs utilisables comme les matériaux dont la résistivité, en volume, est inférieure à 10¹⁰ohm/cm³.The product used to make the coating consists of a powder of a conductive or semiconductor material or a mixture of powders of these materials; among the usable powders, there may be mentioned, for example, carbon, graphite, magnesium oxide, silver oxide, copper oxide or bromide, zinc oxide, titanium oxide, etc .; all these powders seem to be characterized by a relatively high electrical potential compared to other powders having a low or zero electrical potential. We can define usable conductive or semiconductor materials as materials whose resistivity, in volume, is less than 10¹⁰ohm / cm³.

Le procédé utilisé consiste à pulvériser les poudres sur les éléments de renforcement pendant que ceux-ci sont soumis au champ électrostatique produit par deux électrodes comme indiqué ci-dessus. Dans certains cas, il est possible de pulvériser les poudres dans un milieu contenant l'élément de renforcement que l'on soumet simplement au champ électrostatique produit par un courant continu ; mais, le plus souvent, il est préférable d'opérer, comme précédemment décrit, en soumettant tout d'abord l'élément de renforcement à un champ produit par un courant continu (ce qui provoque un gonflement considérable de l'élément de renforcement) puis en soumettant l'élément gonflé au champ produit par un courant alternatif et d'injecter alors la poudre dans le milieu contenant l'élément soumis audit champ. Selon les fibres, il est parfois souhaitable de réaliser ces opérations à une température supérieure à la température ambiante (par exemple, de 25 à 60°C) de façon à faciliter et accélérer d'éventuels phénoménes d'oxydation superficielle provoqués, sur l'élément, par le champ.The method used consists in spraying the powders on the reinforcing elements while these are subjected to the electrostatic field produced by two electrodes as indicated above. In some cases, it is possible to spray the powders in a medium containing the reinforcing element which is simply subjected to the electrostatic field produced by a direct current; but, more often than not, it is preferable to operate, as previously described, by first subjecting the reinforcing element to a field produced by a direct current (which causes considerable swelling of the reinforcing element) then by subjecting the swollen element to the field produced by an alternating current and then injecting the powder into the medium containing the element subjected to said field. Depending on the fibers, it is sometimes desirable to carry out these operations at a temperature above ambient temperature (for example, from 25 to 60 ° C.) so as to facilitate and accelerate possible phenomena of surface oxidation caused, on the element, by the field.

Comme il a été indiqué ci-dessus, le procédé doit être adapté notamment aux éléments de renforcement utilisés ; les paramètres que l'on fait varier sont, outre éventuellement le potentiel appliqué aux électrodes, l'écartement desdites électrodes et la durée du traitement. Ainsi, pour des éléments de renforcement en carbone, on soumettra lesdits éléments au champ produit par un courant continu d'environ 100 000 V appliqué sur des électrodes distantes de 10 mm, la durée d'application étant d'environ 10 min. Si on utilise des éléments de renforcement en amide aromatique, le potentiel de 100 000 V pourra être appliqué à des électrodes écartées de 7 mm et la durée d'application sera d'environ 5 min. Si le champ provient d'un courant alternatif, l'écart entre les électrodes sera d'autant plus grand que les éléments de renforcement seront plus conducteurs ; comme exemple ponctuel, le traitement d'éléments de renforcement en verre se fera avantageusement en appliquant un potentiel de 15 à 30 000 V entre deux électrodes distantes d'environ 20 mm ; la durée d'application étant environ 3 à 5 min.As indicated above, the method must be adapted in particular to the reinforcing elements used; the parameters that are varied are, in addition to the potential applied to the electrodes, the spacing of said electrodes and the duration of the treatment. Thus, for carbon reinforcing elements, these elements will be subjected to the field produced by a direct current of approximately 100,000 V applied to electrodes 10 mm apart, the duration of application being approximately 10 min. If aromatic amide reinforcing elements are used, the potential of 100,000 V can be applied to electrodes spaced 7 mm apart and the application time will be approximately 5 min. If the field comes from an alternating current, the difference between the electrodes will be all the greater as the reinforcing elements are more conductive; as a specific example, the treatment of glass reinforcing elements will advantageously be done by applying a potential of 15 to 30,000 V between two electrodes about 20 mm apart; the duration of application being approximately 3 to 5 min.

Il est clair pour le spécialiste que les éléments de renforcement soumis à ces champs électriques recevront une certaine charge électrique qui contribuera à assurer la bonne adhérence, sur ces éléments, des poudres en matériau conducteur ou semiconducteur.It is clear to the specialist that the reinforcing elements subjected to these electric fields will receive a certain electrical charge which will contribute to ensuring good adhesion, on these elements, of powders of conductive or semiconductor material.

Enfin, on remarquera que le phénomène de mordançage subi par les éléments de renforcement soumis à un champ électrique produit par un courant alternatif est définitif alors que le phénomène de gonflement subi par les éléments de renforcement soumis à un champ électrique produit par un courant continu est transitoire et d'une durée variable selon la nature desdits éléments allant par exemple de 2 à 3 min pour le verre à environ 30 min pour les polyamides aromatiques.Finally, it will be noted that the etching phenomenon undergone by the reinforcing elements subjected to an electric field produced by an alternating current is definitive while the swelling phenomenon undergone by the reinforcing elements subjected to an electric field produced by a direct current is transient and of variable duration depending on the nature of said elements ranging for example from 2 to 3 min for glass to about 30 min for aromatic polyamides.

Comme indiqué précédemment, les éléments de renforcement revêtus selon l'invention peuvent être utilisés dans des matrices très différentes pour produire des matériaux composites. On peut employer pratiquement n'importe quelle matrice organique connue et classiquement utilisée pour la réalisation de matériaux composites. Comme matrice utilisable, on peut citer les résines époxy, les résines organiques-inorganiques, les thermoplastiques, les céramiques et les produits à prise hydraulique ou les résines organiques pauvres.As indicated above, the coated reinforcing elements according to the invention can be used in very different dies to produce composite materials. Virtually any known organic matrix conventionally used for the production of composite materials can be used. As usable matrix, mention may be made of epoxy resins, organic-inorganic resins, thermoplastics, ceramics and products with hydraulic setting or poor organic resins.

Il a été trouvé en effet que les éléments de renforcement revêtus pouvaient, de ce fait, acquérir une compatibilité intéressante vis-à-vis soit des matériaux à prise hydraulique, soit vis-à-vis de matériaux constitués d'une résine inorganique pauvre (colle ou liant à base de silice) chargée en oxyde métallique convenable (alumine par exemple). C'est ainsi, par exemple, que l'on a pu réaliser des matériaux nouveaux comportant un élément de renforcement qui est une fibre de jute revêtue de carbone et une matrice constituée par du plâtre ou du ciment.It has been found, in fact, that the coated reinforcing elements could, as a result, acquire an interesting compatibility with either materials with hydraulic setting, or with materials made of a poor inorganic resin ( glue or binder based on silica) loaded with suitable metal oxide (alumina for example). This is how, for example, we were able to achieve new materials comprising a reinforcing element which is a jute fiber coated with carbon and a matrix constituted by plaster or cement.

Les exemples non limitatifs suivants illustrent l'invention :The following nonlimiting examples illustrate the invention:

Exemple 1Example 1

Des fibres de jute orientées de façon polydirectionnelle sont chauffées à 40°C environ et déposées entre deux électrodes alimentées par un courant continu de 100 000 V. Après une durée de l'ordre de 2 à 3 min, on pulvérise dans l'espace entre lesdites électrodes une fine poudre de graphite et le courant est maintenu pendant environ 2 min.Polydirectionally oriented jute fibers are heated to around 40 ° C and deposited between two electrodes powered by a direct current of 100,000 V. After a period of the order of 2 to 3 min, it is sprayed into the space between said electrodes a fine graphite powder and the current is maintained for approximately 2 min.

On constate que les fibres de jute ont été revêtues d'une mince couche (de l'ordre de 2 à 4 µm) de graphite.It can be seen that the jute fibers have been coated with a thin layer (of the order of 2 to 4 μm) of graphite.

Exemple 2Example 2

Des fibres de verre se présentant sous forme de torons ont été placées entre deux électrodes alimentées par un courant continu de 100 000 V ; au bout d'environ 2 min, on a constaté un gonflement considérable du toron (le volume apparent de celui-ci a été multiplié par 4 environ.Glass fibers in the form of strands were placed between two electrodes supplied by a direct current of 100,000 V; after about 2 min, there was a considerable swelling of the strand (the apparent volume thereof was multiplied by 4 approximately.

Les mêmes électrodes ont été alors alimentées par un courant alternatif de 25 000 V pendant une durée de 3 min ; puis on injecte entre lesdites électrodes du graphite en poudre, et un courant continu de 50 000 V est appliqué pendant 2 min.The same electrodes were then supplied with an alternating current of 25,000 V for a period of 3 min; then powdered graphite is injected between said electrodes, and a direct current of 50,000 V is applied for 2 min.

On recueille des fibres de verre gonflées revêtues d'une couche d'environ 3 µm de graphite.Swollen glass fibers are collected coated with a layer of approximately 3 μm of graphite.

Exemple 3Example 3

Des fibres cellulosiques se présentant sous forme d'une bourre légère sont placées entre deux électrodes alimentées par un courant alternatif de 20 000 V ; on introduit dans l'espace entre ces électrodes une poudre très fine d'oxyde de cuivre et le courant est maintenu pendant 3 min.Cellulosic fibers in the form of a light flock are placed between two electrodes supplied by an alternating current of 20,000 V; a very fine powder of copper oxide is introduced into the space between these electrodes and the current is maintained for 3 min.

On recueille des fibres cellulosiques revêtues d'une couche mince (environ 3 µm) très adhérente, d'oxyde de cuivre.Cellulose fibers are collected coated with a very adherent thin layer (approximately 3 μm), of copper oxide.

Exemple 4Example 4

On a utilisé les fibres revêtues de graphite obtenues dans l'exemple 1 et on a introduit ces fibres revêtues entre deux électrodes alimentées par un courant électrique alternatif de 30 000 V. Au bout de 5 min de traitement, on a pu constater que les fibres revêtues avaient subi superficiellement un mordançage.The fibers coated with graphite obtained in Example 1 were used and these coated fibers were introduced between two electrodes supplied with an alternating electric current of 30,000 V. After 5 min of treatment, it was found that the fibers coated had been superficially etched.

Cet essai prouve que les fibres revêtues selon l'invention sont susceptibles de subir, comme les fibres décrites dans les brevets antérieurs, des phénoménes de gonflement, de mordançage et éventuellement d'oxydation superficielle lorsqu'elles sont disposées entre des électrodes alimentées par un champ haute tension produit par un courant continu et/ou alternatif.This test proves that the coated fibers according to the invention are capable of undergoing, like the fibers described in the previous patents, phenomena of swelling, etching and possibly of surface oxidation when they are placed between electrodes supplied by a field. high voltage produced by direct and / or alternating current.

Exemple 5Example 5

Les fibres obtenues selon l'exemple 1 ont été disposées dans un moule ayant la forme de l'objet fini souhaité (plaque par exemple) ; on a coulé dans ce moule une quantité suffisante pour remplir le moule d'un mélange constitué par du ciment, de l'eau (eau de gâchage) et un liant.The fibers obtained according to Example 1 were placed in a mold having the shape of the desired finished object (plate for example); a sufficient quantity has been poured into this mold to fill the mold with a mixture of cement, water (mixing water) and a binder.

On laisse la prise hydraulique du ciment s'effectuer et on démoule une plaque présentant des propriétés au moins égales à celles des plaques de fibrociment connues. On a réalisé la même expérience en remplaçant le ciment par du plâtre et l'on a obtenu une plaque de plâtre très résistance ; pour obtenir une plaque de plâtre très résistante selon la présente invention de couleur blanche on utilisera, par exemple, un élément de renforcement constitué par des fibres de jute revêtues d'oxyde de titane.The hydraulic setting of the cement is allowed to take place and a plate is demolded having properties at least equal to those of known fiber cement plates. The same experiment was carried out by replacing the cement with plaster and we obtained a very resistant plasterboard; to obtain a very resistant plasterboard according to the present invention of white color, use will be made, for example, of a reinforcing element constituted by jute fibers coated with titanium oxide.

Claims (5)

1. Process for coating reinforcing elements which are preferably in fiber form, characterized in that said reinforcing elements are treated, between two electrodes, by the field obtained with a direct electric current of voltage comprised between 50 and 150,000 V and/or with an alternating electric current of frequency comprised between 50 and 1 000 Hz and of voltage comprised between 10,000 and 30,000 V and which is brought in contact, together with said elements swollen by the preceding treatment, with a powder of a conductive or semi-conductive material.
2. Reinforcing elements usable for producing composite materials, characterized in that they are constituted by a known reinforcing element which has been coated with a conductive or semi-conductive material according to the process of claim 1.
3. Elements according to claim 2, characterized in that the conductive or semi-conductive material is carbon graphite or a metal oxide
4. Composite materials, characterized in that they are constituted by the dispersion, in a known matrix of the reinforcing elements according to one of claims 2 and 3.
5. Composite materials, characterized in that they are constituted by reinforcing elements according to one of claims 2 and 3, dispersed in a matrix constituted by a hydraulic setting compound.
EP88403094A 1987-12-11 1988-12-07 Process for coating fibres and its use in the production of composite materials Expired - Lifetime EP0323292B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT88403094T ATE79419T1 (en) 1987-12-11 1988-12-07 METHOD OF COATING FIBERS AND ITS APPLICATION TO MANUFACTURE OF COMPOSITES.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8717340 1987-12-11
FR8717340A FR2624525B1 (en) 1987-12-11 1987-12-11 FIBER COATING PROCESS AND ITS APPLICATIONS FOR THE PRODUCTION OF COMPOSITE MATERIALS

Publications (2)

Publication Number Publication Date
EP0323292A1 EP0323292A1 (en) 1989-07-05
EP0323292B1 true EP0323292B1 (en) 1992-08-12

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP88403094A Expired - Lifetime EP0323292B1 (en) 1987-12-11 1988-12-07 Process for coating fibres and its use in the production of composite materials

Country Status (7)

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US (1) US5000980A (en)
EP (1) EP0323292B1 (en)
JP (1) JPH0291267A (en)
AT (1) ATE79419T1 (en)
DE (1) DE3873719T2 (en)
ES (1) ES2034338T3 (en)
FR (1) FR2624525B1 (en)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BR9602049A (en) * 1995-04-28 1998-10-06 Shell Int Research Process for the production of lubricating base oils
US6146687A (en) * 1998-11-24 2000-11-14 Gillette Canada Inc. Method of coating a fiber
WO2006081622A1 (en) * 2005-02-03 2006-08-10 Australian Wool Innovation Limited Fibre coating composition
US8192316B2 (en) * 2009-02-03 2012-06-05 The Gates Corporation Belt with wear-resistant anti-static fabric

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3572286A (en) * 1967-10-09 1971-03-23 Texaco Inc Controlled heating of filaments
BE790254A (en) * 1971-10-18 1973-04-18 Ici Ltd CONDUCTIVE TEXTILE MATERIALS
US3834916A (en) * 1972-03-23 1974-09-10 Steel Corp Fiber-reinforced cement composite
US4060648A (en) * 1974-10-15 1977-11-29 Union Carbide Corporation Surface coating process
ZA761096B (en) * 1975-03-03 1977-02-23 Ici Ltd Fibres
JPS6012606A (en) * 1983-07-01 1985-01-23 鐘淵化学工業株式会社 Conductive fiber
US4664936A (en) * 1985-01-30 1987-05-12 Shin-Etsu Chemical Co., Ltd. Aromatic polyamide fiber-based composite prepreg
JPS627110A (en) * 1985-07-03 1987-01-14 東レ株式会社 Manufacture of antistatic electret sheet
JPS6215380A (en) * 1985-07-08 1987-01-23 住友電気工業株式会社 Production of carbon fiber reinforced composite material
JPS62110917A (en) * 1985-11-08 1987-05-22 Toyobo Co Ltd Electrically-conductive conjugated filamentous material
US4853253A (en) * 1987-03-30 1989-08-01 Director General Of Agency Of Industrial Science And Technology Method of activating surface of shaped body formed of synthetic organic polymer

Also Published As

Publication number Publication date
FR2624525A1 (en) 1989-06-16
JPH0291267A (en) 1990-03-30
EP0323292A1 (en) 1989-07-05
US5000980A (en) 1991-03-19
DE3873719D1 (en) 1992-09-17
ATE79419T1 (en) 1992-08-15
DE3873719T2 (en) 1993-03-18
ES2034338T3 (en) 1993-04-01
FR2624525B1 (en) 1993-09-03

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