EP1078123A1 - Composite absorbent materials for aqueous liquid - Google Patents

Composite absorbent materials for aqueous liquid

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Publication number
EP1078123A1
EP1078123A1 EP99910419A EP99910419A EP1078123A1 EP 1078123 A1 EP1078123 A1 EP 1078123A1 EP 99910419 A EP99910419 A EP 99910419A EP 99910419 A EP99910419 A EP 99910419A EP 1078123 A1 EP1078123 A1 EP 1078123A1
Authority
EP
European Patent Office
Prior art keywords
composite
nonwoven
composite according
absorbent
powder
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
EP99910419A
Other languages
German (de)
French (fr)
Inventor
Yves Taupin
Christelle Plaut
Philippe Messeant
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Arkema France SA
Original Assignee
Atofina SA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Atofina SA filed Critical Atofina SA
Publication of EP1078123A1 publication Critical patent/EP1078123A1/en
Ceased legal-status Critical Current

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Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
    • A61L15/00—Chemical aspects of, or use of materials for, bandages, dressings or absorbent pads
    • A61L15/16—Bandages, dressings or absorbent pads for physiological fluids such as urine or blood, e.g. sanitary towels, tampons
    • A61L15/42—Use of materials characterised by their function or physical properties
    • A61L15/60—Liquid-swellable gel-forming materials, e.g. super-absorbents
    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06N—WALL, FLOOR, OR LIKE COVERING MATERIALS, e.g. LINOLEUM, OILCLOTH, ARTIFICIAL LEATHER, ROOFING FELT, CONSISTING OF A FIBROUS WEB COATED WITH A LAYER OF MACROMOLECULAR MATERIAL; FLEXIBLE SHEET MATERIAL NOT OTHERWISE PROVIDED FOR
    • D06N3/00—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof
    • D06N3/0086—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof characterised by the application technique
    • D06N3/0088—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof characterised by the application technique by directly applying the resin
    • D06N3/0093—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof characterised by the application technique by directly applying the resin by applying resin powders; by sintering

Definitions

  • the present invention relates to the industry of multilayer composites capable of absorbing an aqueous liquid and of swelling, and in particular to two-layer composites and to articles containing them such as cables for the transport of energy and articles of hygiene.
  • the composites to which the invention relates can be used in different industries.
  • the electric cables industry for telephony and optical fibers
  • the baby hygiene industry for adult incontinence and feminine hygiene.
  • the cables have at least three distinct parts which are, going from the core to the outside:
  • Absorbent composites are known and widely used in the cable industry. For this application they are introduced into the cable to ensure its tightness during the accidental entry of water. Indeed, when water enters the cable following the deterioration of the outer layer, the composite absorbs this liquid and by swelling prevents the propagation of water.
  • the composites used in cables are generally based on absorbent powder, caught between two layers of nonwoven material.
  • Such a composite known as a three-layer absorbent composite, is known and widely described.
  • EP 0188959 describes electrical cables containing composite materials based on hydroexpansible powder such as modified acrylic polymers, grafted starches, polyacrylamides, carboxymethyl cellulose, enclosed between two layers of nonwoven material. Said powder is fixed to the nonwoven by a water-soluble binder.
  • the water-soluble support On contact with water, the water-soluble support partially dissolves, giving a certain freedom to the powder which will expand rapidly by forming a bead and thus preventing the propagation of the water.
  • the freedom of the powder remains partial and its effectiveness limited.
  • the Applicant has also discovered that the freedom of expansion of the absorbent powder can be further improved by controlling its distribution and the quantity fixed on the nonwoven. Indeed, the Applicant has found that when the absorbent powder is distributed punctually on the nonwoven and preferably in the form of a monolayer, its freedom of expansion and its effectiveness are increased. Because under these conditions the particles of the absorbent powder are no longer trapped and form between them channels thus facilitating the circulation of the liquid and its absorption by the powder.
  • the first object of the invention is an absorbent composite capable of swelling, characterized in that said composite consists of two layers: a flexible support based on non-woven material and at least one absorbent powder fixed to said support by hot melt glue.
  • the mass of the adhesive is 2 to 100 g per m 2 of nonwoven and the mass of the absorbent powder is 5 to 300 g per m 2 .
  • nonwoven materials used in the cable industry are generally thermally or chemically bonded nonwoven polyesters and polyolefins such as polypropylene. These materials can optionally be loaded so as to become semiconductors.
  • the preferred nonwovens for carrying out the invention are polyesters, characterized by a smooth surface and a weight of 10 to 100 g / m 2 , or else filled polyesters having a weight of 50 to 300 g / m 2 .
  • hot-melt adhesive means a mixture consisting of a polymer, a resin, an oil or wax and various additives.
  • the adhesives according to the invention are those described by WO 97/12007.
  • the adhesives used for the implementation of the invention are in particular self-adhesive hotmelt adhesives or not having a melting point close to 150 ° C. and a melt index of between 0.5 and 1000. They are generally made up of polymers. Among these, polymers based on ethylene and alkyl acrylate occupy a privileged position. In general, the alkyl acrylate is chosen from methyl acrylate, butyl acrylate and 2, ethylhexylacrylate.
  • hot-melt adhesive it is also possible, as hot-melt adhesive, to use ethylene-vinyl acetate copolymers or styrene-butadiene-styrene copolymers, or even reactive adhesives such as polyurethanes.
  • the ethylene / vinyl acetate copolymer is used, characterized by an acetate level of 10 to 45% by weight.
  • the glue is deposited on the nonwoven using an engraved roller as described below. It partially or completely covers the surface of the nonwoven.
  • the surface covered by the adhesive is from 10% to 80% of the total surface of the nonwoven and represents from 2 to 100 g per m 2 of nonwoven .
  • the absorbent powder according to the invention is a natural or industrial powder. It is homogeneous and of fine particle size.
  • It is generally chosen from the group consisting of modified acrylic polymers, grafted starches, polyacrylamides, cellulose derivatives such as carboxymethyl cellulose.
  • the preferred absorbent powder according to the invention is a powder based on partially neutralized and crosslinked polyacrylic acid hereinafter designated by SAP. It is characterized by a particle size of less than 800 ⁇ m and an absorption rate of an aqueous solution containing 0.9% NaCl, which can reach 100 g per g of SAP.
  • This powder can be obtained by various methods such as those described by FR 2 710 342 and FR 2 732 973.
  • the absorbent powder must cover at least the entire surface of the adhesive.
  • the amount of powder attached to the nonwoven is 5 to 300 g per m 2 of nonwoven.
  • the composites of the invention as described above can be used in all applications using an absorbent powder. Mention may be made, for information, of cables for transporting energy, diapers for babies, sanitary napkins for adult incontinence and for feminine hygiene.
  • the absorbent powder is trapped between two layers of nonwoven material. 4
  • the nonwoven layer is placed between two rolls, one of them has a smooth surface, the other has an engraved surface.
  • the movement of the nonwoven is ensured by the rotation of the rollers.
  • the hot-melt adhesive is melted in a tank placed in direct contact with the engraved roller. As a result, the molten glue touches the surface of the roller. This one turns the melted glue and deposits it on the nonwoven.
  • the absorbent powder is then sprinkled on the nonwoven coated with glue.
  • the patterns engraved on the roller control the amount of glue deposited on the nonwoven as well as the surface covered and therefore the amount of absorbent powder fixed.
  • an infrared (IR) cell can be installed on the test bench before the removal of SAP.
  • the key parameter is the temperature released by the IR cell at the composite level. The optimum temperature is around 30 ° C above the softening point of the adhesive.
  • a calendering step has been added to the test bench, which has the effect of significantly reducing the dusting of hot-melt composites.
  • Calendering consists of passing the composite between two heated stainless steel rollers while exerting pressure on it: the heat of the rollers makes it possible to reactivate the glue and the pressure exerted simultaneously makes it possible to penetrate the particles of SAP into the glue points.
  • the SAP is thus better attached to the nonwoven and the natural powdering of the composite is eliminated.
  • the glue must be softened but not too much so as not to cause it to diffuse through the nonwoven under the effect of the pressure exerted by the rollers.
  • An optimal temperature of the order of 50 ° C. was used in the context of the tests carried out. 5
  • the amount of adhesive is determined by weighing during the manufacture of the composite.
  • the amount of SAP is determined by weighing during the manufacture of the composite.
  • SAPs copolymer of acrylic acid and crosslinked sodium acrylate
  • the determination by a specific electrode of the amount of sodium in the composite after extraction and the knowledge of the sodium content of the powder make it possible to determine the amount of SAP present in the composite.
  • the displacement of the cover (due to the swelling of the SAP) gives a swelling height in mm.
  • PE II 40 g per m 2 hereinafter designated by PE I, ie a carbon black polyester loaded with a weight of 65 g / m 2 hereinafter designated by PE II
  • the calendering therefore clearly improves the behavior of the SAP on the nonwoven and there is practically negligible dusting in the case where the composite is subjected to an air jet of 3 bars.

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  • Health & Medical Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Animal Behavior & Ethology (AREA)
  • Hematology (AREA)
  • Materials Engineering (AREA)
  • Epidemiology (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Dispersion Chemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • Public Health (AREA)
  • Veterinary Medicine (AREA)
  • Textile Engineering (AREA)
  • Absorbent Articles And Supports Therefor (AREA)
  • Laminated Bodies (AREA)
  • Insulated Conductors (AREA)

Abstract

The invention concerns two-layered composites capable of swelling in the presence of an aqueous liquid. Said composites are based on a superabsorbent powder fixed on a nonwoven flexible material support with self-adhesive glue. The two-layered composites can be used in different industries such as, for example, in the manufacture of cables for transporting energy or in industry producing hygiene articles.

Description

MATERIAUX COMPOSITES ABSORBANTS DE LIQUIDE AQUEUX COMPOSITE MATERIALS ABSORBING AQUEOUS LIQUID
La présente invention se rapporte à l'industrie des composites multicouches aptes à absorber un liquide aqueux et à gonfler, et en particulier aux composites bi-couches et aux articles les contenant tels que les câbles pour le transport d'énergie et les articles d'hygiène.The present invention relates to the industry of multilayer composites capable of absorbing an aqueous liquid and of swelling, and in particular to two-layer composites and to articles containing them such as cables for the transport of energy and articles of hygiene.
Les composites auxquels se rapporte l'invention peuvent être utilisés dans différentes industries. En particulier dans l'industrie des câbles électriques, pour la téléphonie et les fibres optiques et dans l'industrie des articles d'hygiène pour bébés, pour l'incontinence adulte et l'hygiène féminine.The composites to which the invention relates can be used in different industries. In particular in the electric cables industry, for telephony and optical fibers and in the baby hygiene industry, for adult incontinence and feminine hygiene.
Les câbles comportent au moins trois parties distinctes qui sont, en allant du coeur vers l'extérieur :The cables have at least three distinct parts which are, going from the core to the outside:
- un noyau conducteur- a conductive core
- un composite absorbant apte à gonfler- an absorbent composite capable of swelling
- une couche externe isolante.- an insulating outer layer.
Les composites absorbants sont connus et largement utilisés dans l'industrie des câbles. Pour cette application ils sont introduits dans le câble pour assurer son étanchéité lors de l'entrée accidentelle d'eau. En effet, lorsque l'eau pénétre dans le câble suite à la détérioration de la couche externe, le composite absorbe ce liquide et en gonflant empêche la propagation de l'eau.Absorbent composites are known and widely used in the cable industry. For this application they are introduced into the cable to ensure its tightness during the accidental entry of water. Indeed, when water enters the cable following the deterioration of the outer layer, the composite absorbs this liquid and by swelling prevents the propagation of water.
Les composites utilisés dans les câbles sont généralement à base de produit absorbant en poudre, pris entre deux couches de matériau non tissé. Un tel composite, dit composite absorbant tri-couches, est connu et largement décrit.The composites used in cables are generally based on absorbent powder, caught between two layers of nonwoven material. Such a composite, known as a three-layer absorbent composite, is known and widely described.
Par exemple, EP 0188959 décrit des câbles électriques contenant des matériaux composites à base de poudre hydroexpansible telle que les polymères acryliques modifiés, les amidons greffés, les polyacrylamides, la carboxyméthyl cellulose, enfermée entre deux couches de matériau non tissé. Ladite poudre est fixée au non tissé par un liant hydrosoluble.For example, EP 0188959 describes electrical cables containing composite materials based on hydroexpansible powder such as modified acrylic polymers, grafted starches, polyacrylamides, carboxymethyl cellulose, enclosed between two layers of nonwoven material. Said powder is fixed to the nonwoven by a water-soluble binder.
Les composites absorbants tri-couches décrits ci-haut posent le problème de l'efficacité de la poudre absorbante. En effet, celle-ci reste enfermée entre deux couches de non tissé et ne peut pas gonfler librement. De plus il reste des espaces vides dans le câble, dans lesquels l'eau peut se répandre. De ce fait, la quantité d'eau que la poudre peut absorber reste limitée. Ce problème est partiellement résolu par EP 0378940 qui décrit des matériaux composites pour câbles comprenant une poudre hydroexpansible et une poudre thermocollante prises en sandwich entre un support plat et un support partiellement 2The three-layer absorbent composites described above pose the problem of the effectiveness of the absorbent powder. Indeed, it remains enclosed between two layers of nonwoven and cannot swell freely. In addition, there are empty spaces in the cable, in which water can spread. Therefore, the amount of water that the powder can absorb remains limited. This problem is partially solved by EP 0378940 which describes composite materials for cables comprising a hydroexpansible powder and a fusible powder sandwiched between a flat support and a partially support 2
hydrosoluble. Au contact de l'eau le support hydrosoluble se solubilise partiellement en donnant une certaine liberté à la poudre qui va s'expanser rapidement en formant un bourrelet et empêcher ainsi la propagation de l'eau. Mais, malgré la présence du support hydrosoluble, la liberté de la poudre reste partielle et son efficacité limitée.water soluble. On contact with water, the water-soluble support partially dissolves, giving a certain freedom to the powder which will expand rapidly by forming a bead and thus preventing the propagation of the water. However, despite the presence of the water-soluble support, the freedom of the powder remains partial and its effectiveness limited.
La demanderesse a maintenant trouvé que ce problème peut être résolu par l'utilisation dans les câbles d'un composite absorbant bi-couches. En effet, la demanderesse a trouvé que la liberté d'expansion de la poudre et son efficacité peuvent être accrues par la suppression de la couche externe du composite absorbant, c'est-à-dire en remplaçant le composite tri-couches : non tissé / poudre absorbante / non tissé par un composite bi-couches : non tissé / poudre absorbante.We have now found that this problem can be resolved by the use in cables of a two-layer absorbent composite. Indeed, the Applicant has found that the freedom of expansion of the powder and its effectiveness can be increased by removing the outer layer of the absorbent composite, that is to say by replacing the three-layer composite: nonwoven / absorbent powder / non-woven by a two-layer composite: non-woven / absorbent powder.
La demanderesse a aussi découvert qu'on peut encore améliorer la liberté d'expansion de la poudre absorbante en contrôlant sa distribution et la quantité fixée sur le non tissé. En effet, la demanderesse a trouvé que lorsque la poudre absorbante est distribuée ponctuellement sur le non tissé et de préférence sous forme de monocouche, sa liberté d'expansion et son efficacité sont accrues. Car dans ces conditions les particules de la poudre absorbante ne sont plus emprisonnées et forment entre elles des canaux facilitant ainsi la circulation du liquide et son absorption par la poudre.The Applicant has also discovered that the freedom of expansion of the absorbent powder can be further improved by controlling its distribution and the quantity fixed on the nonwoven. Indeed, the Applicant has found that when the absorbent powder is distributed punctually on the nonwoven and preferably in the form of a monolayer, its freedom of expansion and its effectiveness are increased. Because under these conditions the particles of the absorbent powder are no longer trapped and form between them channels thus facilitating the circulation of the liquid and its absorption by the powder.
Le premier objet de l'invention est un composite absorbant apte à gonfler caractérisé en ce que ledit composite est constitué de deux couches : un support souple à base de matériau non tissé et au moins une poudre aborbante fixée audit support par l'intermédiaire d'une colle thermofusible.The first object of the invention is an absorbent composite capable of swelling, characterized in that said composite consists of two layers: a flexible support based on non-woven material and at least one absorbent powder fixed to said support by hot melt glue.
De manière générale la masse de la colle est de 2 à 100 g par m2 de non tissé et la masse de la poudre absorbante est de 5 à 300 g par m2.In general, the mass of the adhesive is 2 to 100 g per m 2 of nonwoven and the mass of the absorbent powder is 5 to 300 g per m 2 .
Les matériaux non tissés utilisés dans l'industrie du câble sont généralement les polyesters non tissés liés thermiquement ou chimiquement et les polyoléfines telles que le polypropylène. Ces matériaux peuvent éventuellement être chargés de manière à devenir semi-conducteurs.The nonwoven materials used in the cable industry are generally thermally or chemically bonded nonwoven polyesters and polyolefins such as polypropylene. These materials can optionally be loaded so as to become semiconductors.
Les non tissés préférés pour réaliser l'invention sont les polyesters, caractérisés par une surface lisse et un poids de 10 à 100 g/m2, ou encore les polyesters chargés ayant un poids de 50 à 300 g/m2.The preferred nonwovens for carrying out the invention are polyesters, characterized by a smooth surface and a weight of 10 to 100 g / m 2 , or else filled polyesters having a weight of 50 to 300 g / m 2 .
D'une manière générale par colle thermofusible on entend un mélange constitué d'un polymère, d'une résine, d'une huile ou cire et de divers additifs. Les colles selon l'invention sont celles décrites par WO 97/12007.Generally speaking, hot-melt adhesive means a mixture consisting of a polymer, a resin, an oil or wax and various additives. The adhesives according to the invention are those described by WO 97/12007.
A titre indicatif, les colles utilisées pour la mise en oeuvre de l'invention sont notamment les colles thermofusibles auto adhésives ou non ayant un point de fusion proche de 150°C et un indice de fluidité compris entre 0,5 et 1000. Elles sont généralement constituées de polymères. Parmi ceux-ci les polymères à base d'éthylène et d'acrylate d'alkyle occupent une position privilégiée. En général l'acrylate d'alkyle est choisi parmi l'acrylate de méthyle, l'acrylate de butyle et le 2, éthylhexylacrylate.As an indication, the adhesives used for the implementation of the invention These are in particular self-adhesive hotmelt adhesives or not having a melting point close to 150 ° C. and a melt index of between 0.5 and 1000. They are generally made up of polymers. Among these, polymers based on ethylene and alkyl acrylate occupy a privileged position. In general, the alkyl acrylate is chosen from methyl acrylate, butyl acrylate and 2, ethylhexylacrylate.
On peut aussi, comme colle thermofusible, utiliser les copolymères éthylène - acétate de vinyle ou les copolymères styrène - butadiène - styrène, ou encore les colles réactives telles que les polyuréthanes.It is also possible, as hot-melt adhesive, to use ethylene-vinyl acetate copolymers or styrene-butadiene-styrene copolymers, or even reactive adhesives such as polyurethanes.
De manière avantageuse on utilise le copolymère éthylène / acétate de vinyle caractérisé par un taux d'acétate de 10 à 45 % en poids.Advantageously, the ethylene / vinyl acetate copolymer is used, characterized by an acetate level of 10 to 45% by weight.
La colle est déposée sur le non tissé à l'aide d'un rouleau gravé comme décrit plus loin. Elle recouvre partiellement ou totalement la surface du non tissé. Lorsqu'on souhaite donner le maximum de liberté d'expansion à la poudre absorbante, la surface recouverte par la colle est de 10 % à 80 % de la surface totale du non tissé et représente de 2 à 100 g par m2 de non tissé.The glue is deposited on the nonwoven using an engraved roller as described below. It partially or completely covers the surface of the nonwoven. When it is desired to give maximum freedom of expansion to the absorbent powder, the surface covered by the adhesive is from 10% to 80% of the total surface of the nonwoven and represents from 2 to 100 g per m 2 of nonwoven .
La poudre absorbante selon l'invention est une poudre naturelle ou industrielle. Elle est homogène et de fine granulométrie.The absorbent powder according to the invention is a natural or industrial powder. It is homogeneous and of fine particle size.
Elle est généralement choisie dans le groupe constitué de polymères acryliques modifiés, d'amidons greffés, de polyacrylamides, des dérivés de la cellulose tels que la carboxyméthyl cellulose.It is generally chosen from the group consisting of modified acrylic polymers, grafted starches, polyacrylamides, cellulose derivatives such as carboxymethyl cellulose.
La poudre absorbante préférée selon l'invention est une poudre à base de polyacide acrylique partiellement neutralisé et réticulé désigné ci-après par SAP. Elle est caractérisée par une taille de particules inférieure à 800 μm et un taux d'absorption, d'une solution aqueuse contenant 0,9 % de NaCI, pouvant atteindre 100 g par g de SAP. Cette poudre peut être obtenue selon différents procédés tels que ceux décrits par FR 2 710 342 et FR 2 732 973.The preferred absorbent powder according to the invention is a powder based on partially neutralized and crosslinked polyacrylic acid hereinafter designated by SAP. It is characterized by a particle size of less than 800 μm and an absorption rate of an aqueous solution containing 0.9% NaCl, which can reach 100 g per g of SAP. This powder can be obtained by various methods such as those described by FR 2 710 342 and FR 2 732 973.
La poudre absorbante doit couvrir au moins la totalité de la surface de la colle.The absorbent powder must cover at least the entire surface of the adhesive.
La quantité de poudre fixée sur le non tissé est de 5 à 300 g par m2 de non tissé.The amount of powder attached to the nonwoven is 5 to 300 g per m 2 of nonwoven.
Les composites de l'invention tels que décrits précédemment peuvent être utilisés dans toutes les applications mettant en oeuvre une poudre absorbante. On peut citer à titre indicatif les câbles pour le transport d'énergie, les couches culottes pour bébés, les serviettes hygiéniques pour l'incontinence adulte et pour l'hygiène féminine.The composites of the invention as described above can be used in all applications using an absorbent powder. Mention may be made, for information, of cables for transporting energy, diapers for babies, sanitary napkins for adult incontinence and for feminine hygiene.
De manière générale, dans ces applications, la poudre absorbante est emprisonnée entre deux couches de matériau non tissé. 4Generally, in these applications, the absorbent powder is trapped between two layers of nonwoven material. 4
La demanderesse a découvert que le remplacement d'un tel système par les composites bi-couches de l'invention procure, comme décrit précédemment, un certain nombre d'avantages, tels que l'efficacité de la poudre et la réduction du coût.The Applicant has discovered that the replacement of such a system with the two-layer composites of the invention provides, as described above, a certain number of advantages, such as the effectiveness of the powder and the reduction in cost.
Une des manières de réaliser le composite absorbant bi-couches est la suivante :One of the ways to make the two-layer absorbent composite is as follows:
La couche de non tissé est placée entre deux rouleaux, l'un d'eux a une surface lisse, l'autre a une surface gravée. Le déplacement du non tissé est assuré par la rotation des rouleaux. La colle thermofusible est fondue dans une cuve placée en contact direct avec le rouleau gravé. De ce fait la colle fondue vient toucher la surface du rouleau. Celui-ci en tournant entraîne la colle fondue et la dépose sur le non tissé. La poudre absorbante est ensuite saupoudrée sur le non tissé enduit de colle. Les motifs gravés sur le rouleau contrôlent la quantité de colle déposée sur le non tissé ainsi que la surface recouverte et de ce fait la quantité de poudre absorbante fixée.The nonwoven layer is placed between two rolls, one of them has a smooth surface, the other has an engraved surface. The movement of the nonwoven is ensured by the rotation of the rollers. The hot-melt adhesive is melted in a tank placed in direct contact with the engraved roller. As a result, the molten glue touches the surface of the roller. This one turns the melted glue and deposits it on the nonwoven. The absorbent powder is then sprinkled on the nonwoven coated with glue. The patterns engraved on the roller control the amount of glue deposited on the nonwoven as well as the surface covered and therefore the amount of absorbent powder fixed.
Pour améliorer l'efficacité du procédé décrit précédemment, les perfectionnements A et B suivants peuvent être apportés conjointement ou non.To improve the efficiency of the process described above, the following improvements A and B can be made together or not.
- Perfectionnement A- Improvement A
Afin d'augmenter le temps d'ouverture des colles (et donc de permettre une meilleure adhésion de la poudre absorbante (SAP) au non-tissé), une cellule infra-rouge (IR) peut être installée sur le banc d'essai avant la dépose de SAP. Le paramètre clé est la température dégagée par la cellule IR au niveau du composite. La température optimale se situe 30 °C environ au-dessus du point de ramollissement de la colle.In order to increase the opening time of the adhesives (and therefore to allow better adhesion of the absorbent powder (SAP) to the nonwoven), an infrared (IR) cell can be installed on the test bench before the removal of SAP. The key parameter is the temperature released by the IR cell at the composite level. The optimum temperature is around 30 ° C above the softening point of the adhesive.
- Perfectionnement B- Improvement B
Une étape de calandrage a été ajoutée au banc d'essai, ce qui a pour effet de diminuer nettement le poudrage des composites hot-melt.A calendering step has been added to the test bench, which has the effect of significantly reducing the dusting of hot-melt composites.
Le calandrage consiste à faire passer le composite entre deux rouleaux en inox chauffants tout en exerçant dessus une pression : la chaleur des rouleaux permet de réactiver la colle et la pression exercée simultanément permet de faire pénétrer les particules de SAP dans les points de colles. Le SAP est ainsi mieux attaché au non-tissé et le poudrage naturel du composite est éliminé.Calendering consists of passing the composite between two heated stainless steel rollers while exerting pressure on it: the heat of the rollers makes it possible to reactivate the glue and the pressure exerted simultaneously makes it possible to penetrate the particles of SAP into the glue points. The SAP is thus better attached to the nonwoven and the natural powdering of the composite is eliminated.
Les différents paramètres clés de ce perfectionnement sont :The different key parameters of this improvement are:
- la température des rouleaux- the temperature of the rollers
Dans ce cas, il faut ramollir la colle mais pas trop pour ne pas la faire diffuser à travers le non-tissé sous l'effet de la pression exercée par les rouleaux. Une température optimale de l'ordre de 50 °C a été retenue dans le cadre des essais réalisés. 5In this case, the glue must be softened but not too much so as not to cause it to diffuse through the nonwoven under the effect of the pressure exerted by the rollers. An optimal temperature of the order of 50 ° C. was used in the context of the tests carried out. 5
- la pression exercée par les rouleaux sur le composite Deux pressions ont été étudiées : 1 .403 et 2.105 T- the pressure exerted by the rollers on the composite Two pressures were studied: 1 .403 and 2.105 T
Le composite ainsi préparé est caractérisé de la manière suivante :The composite thus prepared is characterized as follows:
• Quantité de colle• Amount of glue
La quantité de colle est déterminée par pesée lors de la fabrication du composite.The amount of adhesive is determined by weighing during the manufacture of the composite.
• Quantité de poudre absorbante (SAP)• Amount of absorbent powder (SAP)
Une détermination de la quantité de SAP est effectuée par pesée lors de la fabrication du composite.The amount of SAP is determined by weighing during the manufacture of the composite.
Elle peut également être déterminée sur le produit final par un dosage de sodium : les SAP (copolymère d'acide acrylique et d'acrylate de sodium réticulé) contiennent une quantité de sodium fixe imposée par le taux de neutralisation.It can also be determined on the final product by a sodium assay: SAPs (copolymer of acrylic acid and crosslinked sodium acrylate) contain a fixed amount of sodium imposed by the neutralization rate.
Ainsi la détermination par une électrode spécifique de la quantité de sodium dans le composite après extraction et la connaissance de la teneur en sodium de la poudre permettent de déterminer la quantité de SAP présente dans le composite.Thus, the determination by a specific electrode of the amount of sodium in the composite after extraction and the knowledge of the sodium content of the powder make it possible to determine the amount of SAP present in the composite.
• Performances• Performances
On s'intéresse principalement à la détermination de la hauteur de gonflement du SAP déterminée de la manière suivante : 0, 1 g de SAP est introduit dans un réceptacle sur lequel est placé un couvercle. Ce couvercle est percé de trous afin de laisser passer le liquide. On verse ensuite 100 ml d'eau distillée ce qui entraîne le gonflement du SAP.We are mainly interested in determining the swelling height of SAP determined as follows: 0.1 g of SAP is introduced into a receptacle on which a cover is placed. This cover is pierced with holes in order to let the liquid pass. Then poured 100 ml of distilled water which causes the swelling of the SAP.
Le déplacement du couvercle (dû au gonflement du SAP) donne une hauteur de gonflement en mm. On s'intéresse à la hauteur de gonflement à 1 et 3 minutes.The displacement of the cover (due to the swelling of the SAP) gives a swelling height in mm. We are interested in the swelling height at 1 and 3 minutes.
Exemples 1 à 6Examples 1 to 6
Les composites des exemples 1 à 6 sont préparés et caractérisés comme décrit précédemment.The composites of Examples 1 to 6 are prepared and characterized as described above.
• Les produits utilisés pour la réalisation de ces exemples sont :• The products used for the realization of these examples are:
- non tissé : soit un polyester lié thermiquement ayant un poids de- non-woven: either a thermally bonded polyester having a weight of
40 g par m2 désigné ci-après par PE I, soit un polyester chargé noir du carbone ayant un poids de 65 g/m2 désigné ci-après par PE II40 g per m 2 hereinafter designated by PE I, ie a carbon black polyester loaded with a weight of 65 g / m 2 hereinafter designated by PE II
- colle de type autoadhésif thermofusible à 100 % de matière active. Elle se présente sous forme de blocs autoprotégés. Son point de ramollissement se situe entre 71 et 81 °C. Sa forme liquide permet un dépôt constant sur le rouleau gravé et un transfert homogène sur le non tissé. Elle est constituée essentiellement d'un copolymère type éthylène-acétate de vinyle. Poudre superabsorbante Les SAP utilisés sont :- self-adhesive type hot-melt adhesive 100% active material. It comes in the form of self-protected blocks. Its softening point is between 71 and 81 ° C. Its liquid form allows a constant deposit on the engraved roller and a homogeneous transfer on the nonwoven. It essentially consists of an ethylene-vinyl acetate type copolymer. Superabsorbent powder The SAPs used are:
- des billes unitaires non agglomérées ayant une granulométrie optimisée centrée sur 280 μm (ci-après désignés par TAC 45)- non-agglomerated unitary balls having an optimized particle size centered on 280 μm (hereinafter designated by TAC 45)
- des billes en "choux fleur" caractérisées par un taux d'absorption de 70 g/g (ci-après désignées par S 35)- cauliflower balls characterized by an absorption rate of 70 g / g (hereinafter designated by S 35)
- des billes agglomérées de diamètre de 450 μm et un taux d'absorption de 65 g/g (désignées par D 60).- agglomerated beads with a diameter of 450 μm and an absorption rate of 65 g / g (designated by D 60).
• Pour réaliser ces exemples deux rouleaux gravés ont été utilisés. L'un référencé A permet une couverture de 25 % et un dépôt de colle de 8 g par m2, l'autre référencé B permet une couverture de 19 % et un dépôt de colle de 4,5 g par m2.• To make these examples, two engraved rollers were used. One referenced A provides 25% coverage and an adhesive deposit of 8 g per m 2 , the other referenced B provides 19% coverage and an adhesive deposit of 4.5 g per m 2 .
Le tableau suivant résume les caractéristiques et les performances des composites préparés.The following table summarizes the characteristics and performance of the composites prepared.
Exemple n° 1 2 3 4 5 6Example 1 2 3 4 5 6
Non tissé PE I PE I PE I PE I PE II PE IINon woven PE I PE I PE I PE I PE II PE II
Rouleau gravé A B A A A ARoll engraved A B A A A A
SAP utilisé D 60 D 60 S 35 TAC 45 D 60 S 35SAP used D 60 D 60 S 35 TAC 45 D 60 S 35
SAP fixé en g/m2 182 214 60 63 183 51SAP fixed in g / m 2 182 214 60 63 183 51
Gonflement 1 min en mm 18,3 17,5 18, 1 16 18,2 18,2Swelling 1 min in mm 18.3 17.5 18, 1 16 18.2 18.2
Gonflement 3 min en mm 18,9 18,6 18, 1 18,3 19,2 18,2Swelling 3 min in mm 18.9 18.6 18, 1 18.3 19.2 18.2
Exemple 7Example 7
Quantification du poudrage de ces compositesPowder quantification of these composites
L'amélioration apportée par le calandrage sur le poudrage des composites a été quantifiée à l'aide du test suivant :The improvement provided by calendering on the powder coating of composites was quantified using the following test:
Mode opératoire : la surface du composite (10 cm x 7 cm) est balayée avec un jet d'air de 3 bars à une distance de 5 cm. La perte de masse du composite (représentant le SAP qui s'est détaché) est déterminée par pesée.Procedure: the composite surface (10 cm x 7 cm) is scanned with an air jet of 3 bars at a distance of 5 cm. The loss of mass of the composite (representing the SAP which has come off) is determined by weighing.
Les résultats obtenus avec le composite de l'exemple 1 sont regroupés dans le tableau ci-dessous.The results obtained with the composite of Example 1 are collated in the table below.
% de perte par rapport à la masse initiale du composite% loss compared to the initial mass of the composite
Durée de balayage (s) Composite non calandre Composite calandre (2, 105 T)Sweeping time (s) Non-calender composite Calender composite (2, 105 T)
30 0.05 0.0230 0.05 0.02
60 0.07 0.03 120 0.1 1 0.0360 0.07 0.03 120 0.1 1 0.03
Le calandrage améliore donc nettement la tenue du SAP sur le non-tissé et on observe un poudrage pratiquement négligeable dans le cas où le composite est soumis à un jet d"air de 3 bars. The calendering therefore clearly improves the behavior of the SAP on the nonwoven and there is practically negligible dusting in the case where the composite is subjected to an air jet of 3 bars.

Claims

7REVENDICATIONS 7 CLAIMS
1 . Matériau composite susceptible d'absorber un liquide aqueux et de gonfler caractérisé en ce que ledit composite est un composite bi-couches contenant :1. Composite material capable of absorbing an aqueous liquid and of swelling, characterized in that said composite is a two-layer composite containing:
- un support souple de matériau non tissé- a flexible support of nonwoven material
- de 5 à 300 g par m2 de non tissé d'une poudre absorbante fixée sur le non tissé par l'intermédiaire d'une colle thermofusible autoadhésive.- from 5 to 300 g per m 2 of nonwoven of an absorbent powder fixed on the nonwoven by means of a self-adhesive hot-melt adhesive.
2. Composite selon la revendication 1 caractérisé en ce que la poudre absorbante couvre de 10 à 80 % de la surface totale du non tissé.2. Composite according to claim 1 characterized in that the absorbent powder covers from 10 to 80% of the total surface of the nonwoven.
3. Composite selon la revendication 1 ou 2 caractérisé en ce que la poudre absorbante est choisie dans le groupe constitué de polymères acryliques modifiés tels que le polyacide acrylique partiellement neutralisé et réticulé, des amidons greffés, de polyacrylamides, des dérivés de la cellulose tels que la carboxyméthylcellulose.3. Composite according to claim 1 or 2 characterized in that the absorbent powder is chosen from the group consisting of modified acrylic polymers such as partially neutralized and crosslinked acrylic polyacid, grafted starches, polyacrylamides, cellulose derivatives such as carboxymethylcellulose.
4. Composite selon la revendication 3 caractérisé en ce que la poudre absorbante est le polyacide acrylique partiellement neutralisé et réticulé.4. Composite according to claim 3 characterized in that the absorbent powder is the partially neutralized and crosslinked polyacrylic acid.
5. Composite selon l'une quelconque des revendications 1 à 4 caractérisé en ce que le matériau non tissé est un polyester lié thermiquement ou chimiquement ou une polyoléfine telle que le polypropylène.5. Composite according to any one of claims 1 to 4 characterized in that the nonwoven material is a thermally or chemically bonded polyester or a polyolefin such as polypropylene.
6. Composite selon l'une quelconque des revendications 1 à 5 caractérisé en ce que la colle thermofusible autoadhésive est choisie dans le groupe contenant:6. Composite according to any one of claims 1 to 5 characterized in that the self-adhesive hot-melt adhesive is chosen from the group containing:
- les copolymères éthylène-acétate de vinyle- ethylene-vinyl acetate copolymers
- les copolymères styrène-butadiène-styrène- styrene-butadiene-styrene copolymers
- les colles réactives telles que les polyuréthanes- reactive adhesives such as polyurethanes
- les colles à base de polymères obtenus à partir de l'éthylène et d'un acrylate alkyle tels que l'acrylate de méthyle, l'acrylate de butyle ou le 2 éthylhexylacrylate.- adhesives based on polymers obtained from ethylene and an alkyl acrylate such as methyl acrylate, butyl acrylate or 2 ethylhexylacrylate.
7. Composite selon la revendication 6 caractérisé en ce que la colle thermofusible autoadhésive est un copolymère éthylène-acétate de vinyle. 87. Composite according to claim 6 characterized in that the self-adhesive hot-melt adhesive is an ethylene-vinyl acetate copolymer. 8
8. Câble pour le transport d'énergie électrique, de télécommunications caractérisé en ce qu'il renferme un composite bi-couches absorbant selon l'une des revendications 1 à 7.8. Cable for the transport of electrical energy, telecommunications characterized in that it contains a two-layer absorbent composite according to one of claims 1 to 7.
9. Article d'hygiène tels que les couches culottes, les serviettes pour l'incontinence adulte et l'hygiène féminine caractérisé en ce qu'il renferme un composite bi-couches absorbant selon l'une des revendications 1 à 7. 9. Hygiene article such as diapers, towels for adult incontinence and feminine hygiene, characterized in that it contains a two-layer absorbent composite according to one of claims 1 to 7.
EP99910419A 1998-04-03 1999-03-23 Composite absorbent materials for aqueous liquid Ceased EP1078123A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
FR9804184 1998-04-03
FR9804184A FR2776955B1 (en) 1998-04-03 1998-04-03 COMPOSITE MATERIALS ABSORBING AQUEOUS LIQUID
PCT/FR1999/000675 WO1999051809A1 (en) 1998-04-03 1999-03-23 Composite absorbent materials for aqueous liquid

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DE20120392U1 (en) * 2001-12-17 2002-03-14 Klein Hans Georg Flexible sheets, especially for the production of protective clothing
EP1534515A2 (en) * 2002-08-15 2005-06-01 Paul Vogt Sealing mat and sealing web comprising a superabsorbent layer, method for the production thereof, and use thereof
DE10339178A1 (en) * 2003-08-21 2005-03-17 Deutsche Gelatine-Fabriken Stoess Ag Water storage material
DE10342123A1 (en) * 2003-09-10 2005-04-07 Innovatec Microfibre Technology Gmbh & Co. Kg Multilayer fleece arrangement
BE1023792B1 (en) * 2015-10-07 2017-07-27 Syral Belgium Nv A COATING COMPOSITION INCLUDING A STARCH HYDROLYSATE FOR THERMAL COATING

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JPS5845053A (en) * 1981-09-10 1983-03-16 ダイニツク株式会社 Manufacture of long-sized laminated sheet-shaped article having high water-absorbing function
JPS6128003A (en) * 1984-07-13 1986-02-07 ユニ・チヤ−ム株式会社 Absorber in sanitary article and its production
FR2575110B1 (en) * 1984-12-21 1987-10-16 Intissel Sa WATERPROOFING COMPOSITE MATERIAL, ITS PREPARATION AND COMPOSITION FOR USE THEREOF, AS WELL AS ITS USES
FR2640547B1 (en) * 1988-12-20 1991-03-29 Intissel Sa COMPOSITE MATERIAL CAPABLE OF INFLATING IN THE PRESENCE OF WATER, SUPPORTS FOR USE IN THE PRODUCTION THEREOF AND USES THEREOF
TW200394B (en) * 1991-01-25 1993-02-21 Kao Corp
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JP2865996B2 (en) * 1993-12-02 1999-03-08 株式会社クラレ Manufacturing method of water barrier material
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CN1301322A (en) 2001-06-27
AU2938599A (en) 1999-10-25
FR2776955B1 (en) 2000-05-05

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