EP1608805A1

EP1608805A1 - Basalt containing fabric

Info

Publication number: EP1608805A1
Application number: EP03711726A
Authority: EP
Inventors: Karel Degroote
Original assignee: Groep Masureel Veredeling
Current assignee: Groep Masureel Veredeling
Priority date: 2003-04-04
Filing date: 2003-04-04
Publication date: 2005-12-28
Also published as: WO2004088019A1; AU2003218541A1

Abstract

Product comprising: - a basalt fabric with a weight comprised between 100 g/m2 and 2000 g/m2; - a primer coating suitable for silicone elastomer, the weight of primer being comprised between 10 and 200 g/m2; - at least a silicone elastomer layer coating a face of the fabric provided with a primer layer.

Description

Basalt containing fabric

The state of the art

Basalt fibers are well known in the art. They were developed starting in the seventies - mainly in the ex-USRR, with noted activities in the USA and to a lesser degree in Italy, UK, France, Germany - initially as wool, later on the basis of continuous extruded filaments.

Basalt fibers are sized at the filament extrusion step in order to improve some of their properties, like smoothening of the filament surface (i.e. filling possible surface micro cracks and hiding surface defects) to reduce the probability of filament breakage and decreasing the fiber friction coefficient to facilitate further processing steps as weaving, knitting, braiding, etc.

US 4778844 teaches for example polyurethane flame retardant products consisting of polyurethane foam, possibly combined with basalt fibers or wool.

The reinforcement of polymers, such as epoxy, with basalt fibers, i.e. composite material, has already been taught by Subramanian et al in Sampe Quarterly, July 1977, pages 1 to 11.

It is also known to manufacture fabrics (knitted, woven, braided, non woven, combinations of said technics, etc.) from basalt yarns (made of basalt continuous filaments or fibers). The problems of these fabrics are : - instability of the weave or fabric and vulnerability to defects during transportation and handling. These instability and vulnerability are mainly due to the low friction coefficient of the sized basalt fibers ;.. - instability of the sewn fabric at the seam ; - breakage problem when submitted to a curvature, whereby the fabrics cannot be sewn and/or folded, due to the high stiffness of basalt ;

- naked basalt fabric may irritate the skin when handled, due to the small diameter of the basalt filament ends and their stiffness ; - Etc.

Although the good fire resistance of basalt fibers, basalt fabrics have not been widely used due to the above mentioned problems, for making clothes, especially fire protection clothes, curtains, etc. Indeed, if the fabric is not stable, is irritating and can be broken by folding, such a fabric can not provide a safe fire protection.

It has been proposed by Applicant (WO- A- 02 086213) to provide a thin polyester polyurethane coating on at least a face of a basalt fabric (advantageously on both of its faces), so as to obtain a flexible and stable fabric solving the problems of the known and marketed basalt fabrics. When bending and pinching the fabric of the invention, no or at least substantially no filament breakage appears. Due to its stability, flexibility and resistance to breakage when folded and pinched, the coated fabric of the invention has various possible applications, for example in fire protection, especially in the manufacture of fire protecting product, such as for example clothes or parts thereof.

Said product is however not suitable for some application due to the formation of smoke. Furthermore, the product as disclosed in said document, while ensuring a sufficient drapeability, has an abrasion resistance, which is often not considered as sufficient for special applications. The PUR layer has an abrasion resistance of less than 20,000 cycles, according to the Martindale test BS 5690; 1991.

The present invention has for subject matter a flexible and stable fabric having a low flammability (less than Ml, preferably M0 according to the norm NF P92-503 : 1995 ; NF P92-507 : 1997) and a low smoke generation (less than FI, preferably F0 according to the norm NF XlO-702-1 : 1995 and NF X 10-702-3 : 1994, toxicity in accordance with NF X 70-100 : 1986), said fabric having advantageously furthermore an excellent abrasion resistance of more than 25,000 cycles, advantageously more than 20,000 cycles, preferably more than 40,000 cycles, most preferably more than 50,000 cycles, while maintaining good flexibility and advantageously good resistance to aging.

Brief description of the invention

The invention relates to a flexible product comprising at least: - a fabric (woven, non woven, knitted, braided, satin,plain or not, etc. and combinations thereof) made at least of yarns containing at least basalt fibers

(preferably basalt continuous filament fibers or BCF fibers), said fabric having a weight comprised between 70 g/m² and 4000 g/m², advantageously from 100 to 3500g/m², preferably less than 2500g/m ; a primer layer coating at least partly said yarns or fibers, said primer being suitable for silicone elastomer(s), the dry weight of primer being comprised between 10 and 200 g/m², advantageously between 20 and 100 g/m², preferably between 25 and 50 g/m² ; at least a silicone elastomer layer coating at least partly a face of the fabric provided with a primer coating, said silicone elastomer layer having a dry weight comprised between 20 and 500 g/m², advantageously between 40 and

400 g/m², preferably between 50 and 200 g/m², said weight being calculated on basis of the weight of the silicone elastomer present in said coating layer (i.e. without taking into consideration additives, solid particles, colouring agents, powders , etc possibly present in the elastomer layer) (The total weight of the silicone elastomer layer, i.e. with additives, solid particles, etc. is advantageously comprised between 50 and 1000g/m²); in which the primer coating and the silicone elastomer coating are selected so as to provide a fire resistance with a flammability of less than Ml (preferably M0) according to the norm NF P92-503 : 1995 ; NF P92-507 : 1997 and a smoke generation of less than FI (preferably F0) according to the norm NF XlO-702-1 : 1995 and NF X 10-702-3 : 1994 (toxicity in accordance with NF X 70-100 : 1986). When the fabric is a tridimensional fabric or has a tridimensional structure, such as a closed structure, such as cylindrical structure, the weight per surface is determined after developing the tridimensional fabric in a plane.

The silicone elastomer layer has preferably an abrasion resistance of more than 25,000 cycles, advantageously more than 40,000 cycles, preferably more than 50,000 cycles according to the Martindale test BS 5690; 1991.

While the primer layer is advantageously free or substantially free of any additives, the silicone elastomer layer comprises advantageously less than 25% by weight of solid particles and possible additives. The additives and solid particles, when present, are selected so as to be unapt to generate smoke (FI or preferably F0 according to norm NF XlO-702-1 : 1995 and NF X 10-702-3 : 1994 (toxicity in accordance with NF X 70-100 : 1986)).

The flexible product of the invention is such that the coated face can be folded and pinched (pressing the folded face between fingers along the folding line), whereby two portions of the coated faces contact each other. The folding is carried out with a radius of curvature of less than 2mm, advantageously of less than 1mm, substantially without visible breakage of basalt fibers or filaments on the coated face. When only a face of the fabric is coated, the folding of the fabric does not form visible broken basalt fibers or filament on the coated side of the fabric, while some broken fibers or filaments are visible along the folding line on the uncoated side. The ratio number of visible broken fibers or filaments on the coated side along the folding line / number of visible broken fibers on the uncoated face along the folding line is advantageously less than 0.1, preferably less than 0.05, most preferably less than 0.01, especially less than 0.001, or even more. The number of visible broken fibers or filaments even on the uncoated face along the folding line is in any case low due to the passage of some coating agent between adjacent filaments or fibers. When the two opposite faces of the fabric are coated with a primer layer and with a silicone elastomer layer, substantially no broken basalt fibers are visible on both sides along the bending line (radius of curvature of less than 1mm).

Advantageously the weight ratio weight of the silicone elastomer layer/weight of primer layer is comprised between 3 and 30, preferably between 5 and 20, most preferably between 10 and 20.

The basalt fiber comprises advantageously more than 43% by weight, preferably at least 46%o by weight of SiO₂, more preferably more than 50%, specifically more than 55%o by weight SiO₂. The basalt fibers are advantageously acid type basalt fibers. The basalt fibers have also advantageously a high Al O₃ content, for example a Al₂O₃ content higher than 18% by weight (for example a content comprised between 18% and 24%), and a low (CaO,MgO) content, for example a (CaO + MgO) content of less than 8% by weight (for example comprised between 5% and 8%).

The primer layer is advantageously a layer obtained from one or more silane esters, said layer contacting preferably directly the basalt fibers, so that said primer layer is bound to silicon atoms present in the basalt fibers.

Examples of preferred silane esters are ethenyl triacetate silane with trimethoxyl-3- propylester or vinyl triacetate silane with trimethoxy-3-propyl ester or allyl triacetate silane with trimethoxy-3-propyl ester or isopropenyl triacetate silane with trimetoxy-3-propylester or ethenyl triacetate silane with tri ethoxyl-3- propylester or vinyl triacetate silane with triethoxy-3-propyl ester or allyl triacetate silane with triethoxy-3-propyl ester or isopropenyl triacetate silane with trietoxy-3 -propylester or combinations thereof.

Said ester can be applied on the basalt fibers as a solution or as a dispersion, for example in a solvent, such as an organic solvent suitable for the silane ester, but preferably as an aqueous dispersion, such as an aqueous dispersion containing less than 10%) by weight, preferably less than 5% by weight silane ester. Preferably, the silicone elastomer layer covers at least substantially uniformly a portion of a face of the fabric provided with a primer layer. According to an embodiment, a first face of the fabric is substantially completely coated with a polyester polyurethane layer, said coating being substantially uniform. The other face of the fabric (i.e. the face opposite to said first face) is possibly uncoated, but is advantageously also coated with a polymer layer, preferably with a silicone elastomer layer. Different silicone elastomers can be used for coating the two opposite faces of the fabric. However, preferably the same silicone elastomer is used for coating the two opposite faces of the fabric.

According to a specific embodiment, the portion of the face of the fabric coated with a silicone elastomer coating layer has a coating weight distribution such that for each cm² of the portion of the coated fabric, the weight of coating layer varies between 60% and 250%) of the average coating weight, advantageously between 70%) and 150%, preferably between 80% and 130%. A uniform distribution of the coating is advantageous for ensuring substantially uniform properties of the coated fabric (stability, resistance to breakage, etc.).

The yams can comprise some fibers not made from basalt, for example steel fibers, glass fibers (such ass E glass fibers, AR glass fibers, R glass fibers, S glass fibers, HT glass fibers, etc., and combinations thereof), carbon fibers, etc. However, advantageously the yams comprise at least 75% by weight, advantageously more than 85%> by weight, preferably more than 95% by weight of basalt fibers. For example, the yams comprise more than 99% basalt fibers, or is made substantially completely from basalt fibers or filaments.

According to a detail of an embodiment, the silicone elastomer coating layer coating a face of the fabric has a maximum coating weight (wet stage) of 100g/m², advantageously a maximum coating weight of 80g/m², preferably a maximum coating weight of 70g/m². Possibly the said maximum coating weight at the wet stage can be higher than 100g/m², such as 200g/m² or even more.

According to a detail of another embodiment, the silicone elastomer coating layer coating a face of the fabric has a maximum coating weight of 100g/m², advantageously a maximum coating weight of 80g/m², preferably a maximum coating weight of 70g/m². Possibly the said maximum coating weight can be higher than 100g/m².

Preferably, the silicone elastomer layer comprises at least 50%> by weight of silicone elastomer. Most preferably, the silicone elastomer layer comprises more than 75%o by weight silicone elastomer, for example more than 90%> or even more than 95%o. According to an embodiment, the coating layer comprises substantially only silicone elastomer.

According to a detail of a preferred embodiment, the basalt fibers comprises a large number (such as more than 100, for example from 100 to 1000) of continuous basalt filaments having each a diameter comprised between 5 μm and 25 μm, _t preferably between 7μm and 21μm. The yams have a weight comprised between 50 tex and 4000 tex (ltex= lg for a length of 1000m), advantageously between 50 tex and 3000 tex, such as between 80 and lOOOtex, most preferably lower than 500 tex, preferably from 80 to 150 tex for weaving yams and from 150 to 600tex roving yams. The yams have for example an average equivalent diameter [equivalent diameter = 4 x ( surface of the cross section of a yam defined by the outer filaments)/(outer length of the cross section surface defined by the outer filaments)] comprised between 50 and lOOOμm, advantageously between 100 and 500μm, for example between 200 and 400μm, such as about 250μm, about 300μm, about 350 μm.

Possibly, at least a portion of a coated face with a silicone elastomer layer is provided with one or more further layers, such as by calendering, etc.. Said further layer can be a further silicone layer and/or a polyester polyurethane layer or a layer having various properties, such as a heat insulating layer, for example needle felt layer, basalt continuous filament fibers layer, etc. According to a possible embodiment, the fabric is provided with successive silicone elastomer layers, preferably applied the one on another, for example by applying a new silicone elastomer layer after a at least partial curing of the previous silicone elastomer.

Preferably, the portion of the fabric coated with a polyester polyurethane layer has a porosity made of pores of less than 50μm, advantageously of less than 25 μm, preferably of less than lOμm. Said portion is most preferably substantially impermeable to liquids. Most of the times in clothing, some gas permeability is desired and/or even required.

According to a possible embodiment, at least a portion of a silicone elastomer coating layer comprises at least one, for example one or more, pigments and/or coloring pigments and/or metallic pigments (such as aluminum powders, metallic microfibers, etc.) and/or luminescent compounds (such as fluorescent compound(s) and/or a phosphorescent compound(s)).

According to still another possible embodiment, at least a face of the coated fabric (which can be for example a plain fabric or a satin fabric) is associated with a heat insulating layer and/or with a heat insulating layer on its both sides.

According to still another possible embodiment, the coated fabric of the invention is used for covering one or both faces of a substrate, such as a non woven substrate.

The invention relates also to an element comprising at least a product of the invention. Preferably, a portion of the product is sewn with another portion of the product or with another product of anyone of the preceding claims or with another fabrics or layer or sheet. The product of the invention has various uses, such as for making inner layers, outer layers, intermediate layers, interliners in wall, floor, ceiling panels, fire resistance panels, covering laminates, such as for floor, seats, cushions, fire resistant mattresses, protective clothing, such as gloves, pancho's for forest fire fighters, tapes, canisters, tubes, heat protection envelopes (such as for pipes, valves, cables, electrical cables). These possible uses are given hereabove as non limiting examples.

The product of the invention finds thus possible uses in various sectors, such as construction, transport (transport of persons, transport of goods), car industry, trains, fumiture, protective clothes, plant, machinery and equipment, air plane and train seating, fire proof electrical cables or wires, etc.

In order to improve specific uses of the product of the invention, additional finishing coatings are possible, such as coating for soft and continuous contact with the skin (for example obtained by flocking), further silicone coatings (for heat, weather and small impacts protection, elasticity),elastic layer, intumescent layer (for fire-heat insulation), etc.

Preferred silicone elastomers are silicone having a high density after curing, said density being measured for the cured silicone elastomer as such (i.e. free of charges or additives). Preferred silicone elastomers are elastomers having a density after curing of at least 1.3 (g/cm³), most preferably of at least 1.35, such as 1.4, 1.5 or even more. The density is measured at 23 °C in water according to the norm DIN 53479A - ISO 2781. The silicone elastomer has moreover advantageously one or more further properties selected from the group consisting of :

- Shore A hardness (DIN 53 505 - ISO 868) of at least 45, preferably of at least 50, most preferably of at least about 55 ;

- An elongation at break of at least 200%), preferably at least 250%, most preferably from 300 to 400% (DIN 53504-S 1 - ISO 37) ; - A tensile strength (DIN 53 504-S 1 - ISO 37) comprised between 5 and 6.5 N/mm²;

- A tear resistance (ASTM D 624 B) comprised between 10 and 20 N/mm, preferably about 15 mm; - A heat conductivity of about 0 W/m°K ;

- An acidity index of more than 30% ;

- abrasion resistance of more than 25,000 cycles, advantageously more than 40,000 cycles, preferably more than 50,000 cycles according to the Martindale test BS 5690; 1991, - a resistance to aging through immersion in acid, alkalis, solvents, etc., and mixture thereof. high resistance to hydrolysis and water(for example resistance of at least 15 minutes in a boiling solution containg 4% by weight NaOH), i.e. a high resistance to aging; Etc.

The invention relates also to a process for the preparation of a product of the invention, in which a basalt containing fabric is first coated with a primer solution or dispersion, and in which the basalt fabric with a primer coating (possibly after a curing step of the primer coating) is coated at least partly with an aqueous dispersion of a silicone elastomer, said aqueous dispersion containing at least 10% by weight silicone elastomer, advantageously from 20 to 70% by weight, preferably from 30 to 50% by weight silicone elastomer. In said process, advantageously no organic solvents are used, so as to avoid safety problems (fire risks), as well as environmental problems. Preferably, the aqueous dispersion is free or substantially free of emulgators. Therefore, mineral pigments or particles, such as mineral powder, can be added to the coating dispersion before its application on the basalt fabric. Said pigments or other solid additives have advantageously a particle size of less than 2μm, preferably of less than lμm, most preferably less than O.lμm. The invention relates also to the use of a product according to the invention, as fire protection layer.

More specifically, objects of the invention are fire protection clothes, fingers, boots, mittens, gloves, cowls, helmets, pancho's, overcoats, etc., curtains, seat interliners, panel constructions, etc. comprising at least a product or an element of the invention.

Details and characteristics of the invention will appear from the following description, in which reference is made to the attached drawings.

Brief Description of the Drawings

Figure 1 is an upper (enlarged) view of a portion of a coated fabric of the invention;

Figure 2 is a cross section view of the coated fabric of Fig 1 along the line II-II ;

Figure 3 is a cross section view of the coated fabric of Fig 1 when folded ;

Figure 4 is a cross section view of a coated fabric provided with a coating on both of its faces ; Figure 5 is a schematic view of a process for manufacturing a coated fabric of the invention ;

Figure 6 is a schematic view of another process for manufacturing a coated fabric of the invention.

Description of Embodiments

Fig 1 is a schematic view of a coated basalt fabric. The basalt fabric 1 has a weight of about 200g/m² to 400g/m² and is made of warp yams 1A and weft yams IB, said weft yams being crossed with respect to the warp yams for example so as to pass once above and once under said warp yams (plain binding). The density of yams is 10 yams/centimeter for the warp yams and 8 yams/centimeter for the weft yams. The thickness E of the fabric before its coating is about 190μm. The yams are made from continuous basalt filament with a diameter comprised between 7 and 2 lμm, for example about 9μm, about 13μm, about 20μm, and combinations thereof, said yams weigh about 117 tex and comprise about 100 to 1500 filaments, for example about 500 filaments. The basalt filaments are made from acid type basalt, with a SiO₂ content higher than 43%, advantageously higher than 46%, for example higher than 50% by weight. A torsion is carried out on the yams so as improve the cohesion of the filaments the one with respect to the other, for example, the torsion is such that the yam is submitted to a torsion from 5 to 150 times per meter, for example from 70 to 120 times per meter, preferably about 100 times.

A primer coating P made from silane esters with a density of about 1.1 (density at 23°C, in water - DIN 53479A - ISO 2781) is applied on the acid basalt fibers. The primer coating quantity represents about 25 g/m² of fabric. The primer forms a thin continuous or not continuous layer (preferably substantially continuous) on the face of the yams directed towards the face to be provided with the silicone elastomer coating. The silane ester used is ethenyl triacetate silane with trimethoxyl-3-propyl ester. A coating 2 is provided on the upper face of the fabric 1, face which is provided with the primer coating. Said coating is a silicone elastomer coating, for example a coating prepared from Elastosil ® Liquid rubber sold by Wacker Chemie. The coating 2 is applied on the fabric as an aqueous dispersion at a silicone elastomer rate of about 300g/m² (on dry basis), meaning that the thickness of the coating 2 is less than about 220μm, as part of the coating dispersion flows in between filaments of yams. The coated fabric has a total thickness of about 400-500μm. The coating layer is regularly applied so that the thickness of the coating layer varies between 50% and 200%, advantageously from 80%) to 130% of the average coating thickness. The thickness of the coating layer is higher in the valley portions of the fabric. The face 3 of the fabric of Fig 1 remains uncoated. Said face can possibly be precoated with a primer suitable for binding silicone elastomer, so as to ensure a correct primer coating of all the yams of the fabric and so as to ensure that the silicone elastomer liquid rubber possibly traversing the fabric so as to be in contact of faces of yams directed downwardly, will contact a face of the basalt fibers also precoated with a primer.

When folding and pinched the coated fabric of figure 1 at the folding line( two portions of the face 3 are contacting each other - see figure 3), no breakage of basalt filament was visible on the coated face of the fabric, even if the radius of curvature was less than 500μm.

The coated fabric has also the following properties : stable (relative movement between yams is prevented, and even at least some relative movement between filaments are prevented) ;

- the coating is stable and is resistant to UV aging, as well as to temperature aging ; excellent adhesion of the coating on the basalt fabric ;

- the coating does not degrade the basalt fibers or filaments, nor their properties, during the application of the coating, as well as during its burning ;

- the coating does not catch fire with propagating flame, nor produces toxic fumes (coated fabric classified as M0 in accordance to the norm NF P92-503: 1995 and NF P92-507 : 1997), the coating disappears when burning in non toxic fumes (coated fabric classified as F0 in accordance to the norm NF XI 0- 702-1 : 1995, NF X10-702-3 : 1994 and NF X 70-100 : 1986);

- the coated face is non irritating (for example due to the absence of naked basalt filament ends) ;

- excellent resistance to flames after the disappearance of the coating without degradation of the basalt fabric due to the coating process; - economical coating ; excellent flexibility properties and drapeability, whereby the coated fabric can conform to complex or variable form of substrates, such as seats, etc. ;

- possibility of sewing with excellent stability at the seam ;

- possibility to change, without any problem, the color of the fabric by simple addition of pigments to the polyester polyurethane dispersion (possibility to dissimulate without problem the natural color of basalt) ;

- high drapeability ( according to the drape test BS 5058 : 1973) ;

- high tearing resistance ( according to the norm BS 2576 : 1986) ; high resistance to abrasion (an abrasion resistance of more than 50,000 cycles for the silicone elastomer coating, according to the Martindale test BS 5690;

1991.) ;

- high resistance to heat, UV

- high resistance to aging through immersion in water, acids, alkalis, solvents, etc.

Figure 4 is a view of a coated fabric similar to that shown in figure 2, except that both sides of the basalt fabric 1 are provided with a coating layer 2A,2B similar to that disclosed for the coated fabric of Fig 1, the two faces of the fabric being first coated with a primer.

Instead of using a plain fabric as in example, a satin fabric or a knitted fabric can also be used for the preparation of a product according to the invention. For example, the satin fabric (with a satin binding = 5/3) has a weight of 345g/m², a thickness of 270μm, number of weft yams per cm : 13 and a number of warp yams per cm : 22. The yams have a weight corresponding to about 100 tex and are made from about 500 continuous basalt filaments having a diameter of about lOμm. The filaments assembled for forming a yam are submitted to a torsion for example about 100 torsions for a length of lm.

Said fabric was provided with a silicone elastomer layer on one face as for the fabric of figure 1 and on both of its face as for the fabric of figure 4. Figure 5 is a schematic view of a process for manufacturing a coated fabric of Figure 1.

The naked basalt fabric 1 is provided from a roll A and is pulled by a stenter in the dryer 16 and taken by the roll B on which the coated basalt fabric is enrolled. The naked basalt fabric passes through a pair of brake rollers 10 with a torque motor regulated so as to exert a low braking (for example torque motor regulated to less than 15%), advantageously less than 10% of the full braking capacity). The naked fabric 1 passes then in a knife over air system 11 comprising two support rollers 12,13 between which the fabric 1 extends substantially horizontally. A knife 14 contacts a portion of the fabric located between the two rollers 12,13, said knife 14 distributing an aqueous dispersion of silicone elastomer 15. After the coating operation (which can be carried out at a temperature for example from 0°C up to 100°C, advantageously from 10°C up to 65°C, preferably from 15°C up to 40°C), the wet coated fabric Ibis enters in a dryer 16. Said heater 16 comprises the stenter 17 exerting a force on the lateral edges of the fabric so as to limit the lateral or transversal stretching of the basalt fabric to less than 10%, advantageously to less than 2%, preferably so as to avoid or to prevent substantially any transversal stretching during the drying, most preferably so as to exert a kind of negative stretching during the drying. The fabric 1 is moved with a speed for example lower than 40m/minute, such as a speed comprised between 10 and 25m/minute.

The dryer 16 is advantageously using a direct gas heating or steam heating or oil heating, for example heated gas with a temperature comprised between 120°C and 250°C, preferably with a temperature of about 160°C when contacting the fabric to be dried (water evaporation and curing). The heated gas is for example combustion gas, but can also be heated air.

Possibly, before the coating operation, the fabric is prewetted with an aqueous medium or with water. Possibly, also, the coating is made in a vacuum chamber.

The silicone elastomer coating is applied on the basalt fabric after a pretreatment step, namely the formation of a primer layer directly applied on the basalt fiber. When the basalt fabric is already provided with a silanized layer, said layer is advantageously removed at least partly of the fabric, before applying a primer composition suitable for the binding of silicone elastomers. The primer is advantageously applied as an aqueous dispersion and is at least partly cured (preferably only partly cured) before the application of the silicone elastomer liquid dispersion.

Before the application of the primer, the basalt fabric is for example treated with an acid and/or solvent system.

Possibly, the coating operation and/or the drying operation are carried out in a controlled atmosphere, such as in an inert atmosphere (nitrogen).

When the two sides or faces of the fabric 1 have to be provided with a coating layer, the device disclosed in figure 5 is provided with a further coating system, preferably a coating system similar to the system 11. In this case, rollers are provided so as to turn the lower face of the fabric upwards so as to enable the coating thereof with a system similar to the system 11.

Possibly the coating of the other face of the fabric can be operated after the drying of the first coating layer. Advantageously, the drying temperature of the first layer is lower than the curing temperature.

Various dispersions can be used in the process shown in Figure 5. Said dispersion have advantageously a low viscosity for example a viscosity lower than 100 mPa.s at 23°C and a pH comprised between 5 and 8, preferably from 6 to 7.5. Examples of possible silicone elastomer dispersions are given hereafter, said dispersions being used at room temperature for the coating.

Dispersion 1 : aqueous dispersion silicone elastomer ( Elastosil Liquid Rubber® 3001/55 A/B with a platinum catalyst ) with a silicone elastomer content of 40%

Dispersion 2 : aqueous dispersion silicone elastomer ( Elastosil Liquid Rubber® 3001/55 A/B with a platinum catalyst) with a silicone elastomer content of 45%

Dispersion 3 : aqueous dispersion silicone elastomer ( Elastosil Liquid Rubber® 3001/55 A/B with a platinum catalyst) with a silicone elastomer content of 20%>

Dispersion 4 : aqueous dispersion silicone elastomer ( Elastosil Liquid Rubber® 3001/55 A B with a platinum catalyst) with a silicone elastomer content of 20% and with pigment content of 10% (for example kaolin, etc.)

Dispersion 5 : aqueous dispersion silicone elastomer ( Elastosil Liquid Rubber® 3001/55 A/B with a platinum catalyst ) with a silicone elastomer content of 20% and with pigment content of 20% (for example kaolin, etc.)

Dispersion 6 : aqueous dispersion silicone elastomer ( Elastosil Liquid Rubber® 3001/55 A/B with a platinum catalyst) with a silicone elastomer content of 20%) and with a fluorescent pigment content of 5%

Dispersion 7 : aqueous dispersion silicone elastomer ( Elastosil Liquid Rubber® 3001/55 A/B with a platinum catalyst) with a silicone elastomer content of 5% and with a fluorescent pigment content of 5%

Dispersion 8 : aqueous dispersion silicone elastomer (Elastosil Liquid rubber 3001/55 A/B with a platinum catalyst) with a silicone elastomer content of 10% by weight with fume glass (SiO2) particles with a particle size lower than 50μm (such as a particle size between 0.5μm and lOμm)

For the precoating (precoating of the naked basalt fabric with a primer), various primer dispersions can be used, such as :

- aqueous dispersion containing 5% silane ester (ethenyl triacetate silane with trimethoxyl-3-propyl ester);

- aqueous dispersion containing 10%> silane ester (ethenyl triacetate silane with trimethoxyl-3-propyl ester); - aqueous dispersion containing 20 % by weight silane ester (ethenyl triacetate silane with trimethoxyl-3-propyl ester) aqueous dispersion containing 2%_> by weight silane ester (ethenyl triacetate silane with trimethoxyl-3-propyl ester)

The various fabrics coated on one or both faces with one or more of the above dispersion can be sewn without any problem or breaking risks.

Figure 6 shows a specific process for the manufacture of a double coated basalt fabric.

In this figure, the naked basalt fabric 1 enters in a bath 20 containing a primer solution or a primer dispersion. The naked fabric provided with a primer coating is then passing between nip rolls 21 so as to remove excess primer composition. The naked fabric can then be moved, if necessary, in a dryer 22 or a system for accelerating the curing of the primer on the naked fabric. Possibly, before said treatment, the basalt fabric is submitted to a treatment for removing at least partly the sizing agent (such as silane and/or paraffin) possibly used for coating the basalt filament The drying or curing of the primer is for example made by hot air, IR heating, heat nitrogen gas, C0₂ gas, microwave, etc., the primer being for example heated or cured at a temperature from 50°C up to 200°C.

In order to avoid an excessive reaction rate, the fabric provided with a primer coating is submitted to a cooling step 23, so as to reduce the temperature of the fabric to less than 25°C.

The fabric 1 with a primer coating is then passing through the bath 24 containing an aqueous dispersion of silicone elastomer. The fabric is then moved through nip rolls 25 for removing excess silicone elastomer. A knife coater, such as a knife over air enduction ,26 is then used for coating the upper face of the fabric with a sufficient and regular amount of silicone elastomer. Said coater distributes silicone elastomer on the upper face of the fabric. The so coated fabric is then moved in a heating chamber or in a curing chamber 27 for enabling a quick cure of the silicone elastomer.

The drying or curing of the silicone elastomer is for example made by hot air, IR heating, heat nitrogen gas, C0₂ gas, microwave, etc., the primer being for example heated or cured at a temperature from 50°C up to 250°C.

The nip-rolls are for example adapted for admitting a controlled pressure between the rolls, for example a pressure comprised between 2 10⁵Pa and 10 10⁵ Pa. Said nipp-rolls are moved in relation to the movement of the fabric.

The so obtained fabric is provided with a thick upper silicone elastomer layer and with thin lower silicone elastomer layer.

If the fabric has to be provided with two thick silicone elastomer layers, one on its lower face and another on its upper face, it is possible to use a system for reversing the fabric after coating the upper face of the fabric with a silicone elastomer with a knife coater, whereby the lower face becomes the upper face which can then be further treated with a knife coater for distributing uniformly a silicone elastomer.

In the process of figures 5 and 6, aqueous primer dispersion and aqueous silicone elastomer dispersion are preferably used, especially for safety purposes, for environmental purposes, etc. and as it seems that the presence of water in both dispersions seems to be adequate for increasing the possible hydrolysis and/or curing of the primer and/or silicone elastomer.

The silicone elastomer used in said process is preferably halogen free.

Examples of possible fabrics are : woven fabric, design fabrics (plain, sateen, twill, etc.), knitted flat fabric, three dimensional fabrics, etc., such as knitted tubes, braided fabrics such as in tubes, non woven fabric, needlefelt fabrics, etc.

The product of the invention can have various uses, such as for making inner layers in wall, floor, ceiling panels, fire resistance panels, covering laminates, such as for car floor, seats, cushions, fire resistant mattresses, protective clothing, such as gloves, pancho's for forest fire fighters, tapes, canisters, tubes, heat protection envelope (such as for pipe, valves, cables, electrical cables.

Specific application fields are :

• construction : wall, floor and ceiling paneling for building-in fire resistance, fire curtains such as automatically falling down to segment buildings, manufacturing halls, storage areas, tunnel, electrical wire insulation, fire blocking interliners with a thermal insulation function, etc. in case of fire ;

• transportation : flexible rolls of floor covering laminates, fire resistance covering for seats, cushions, etc.

• furniture : fire resistant mattresses, fire blocking interliners in mattresses, plane seats, etc. • protective clothes, especially sewn protective clothes : overcoats, gloves, boots, etc. for example for fire fighter, forest fire fighter ;

• plant, machinery and equipment construction : fire protection of valves, pipes, cables, etc. • stretchable, vandalism proof fire blocking interliners

In the process of figure 6, the coating with the silicone elastomer is advantageously carried out substantially just after the treatment of the basalt fabric with the primer composition. For example, the silicone elastomer coating is carried out less than 30minutes, advantageously less than 15 minutes, most preferably less than 5 minutes after the end of the treatment of the basalt fabric with the primer composition.

Claims

1. Product comprising : - a fabric made at least of yams containing at least basalt fibers, preferably basalt continuous filament fibers, said fabric having a weight comprised between 70 g/m² and 4000 g/m² ;

- a primer coating at least partly said yams or fibers, said primer being suitable for silicone elastomer, the dry weight of primer being comprised between 10 and 200 g/m² ;

- at least a silicone elastomer coating layer coating at least partly a face of the fabric provided with a primer coating, said coating layer having a dry weight comprised between 20 and 500 g/m², advantageously between 40 and 400 g/m², preferably between 50 and 200 g/m², said weight being calculated on basis of the weight of the silicone elastomer present in said coating layer in which the primer coating and the silicone elastomer coating are selected so as to provide a fire resistance with a flammability of less than Ml according to the norm NF P 92-503 : 1995, NF P 92-507 : 1997 and a smoke generation of less than FI according to the norm NF X 10-702-1 : 1995; NF X 10-702-3 : 1994 and NF X 70- 100 : 1986 .

2. The product of claim 1, characterized in that the silicone elastomer layer has an abrasion resistance of more than 25,000 cycles, advantageously more than 40,000 cycles, preferably more than 50,000 cycles according to the Martindale test BS 5690; 1991.

3. The product of claim 1 or 2, characterized in that the primer coating is a layer obtained from one or more silane esters.

4. Product of anyone of the preceding claims, characterized in that the basalt fiber comprises at least 43% by weight of SiO₂, advantageously more than 46%, preferably more than 50%o by weight SiO₂.

5. Product of anyone of the claims 1 to 4, characterized in that the silicone elastomer has a density after curing of at least 1.3, a shore A hardness of at least 45, and an acidity index of more than 30.

6. Product of anyone of the claims 1 to 5, characterized in that the portion of the face of the fabric coated with a silicone elastomer coating layer has a coating weight distribution such that for each cm² of the portion of the coated fabric, the weight of coating layer varies between 60%> and 250%> of the average coating weight, advantageously between 70% and 150%, preferably between 80% and 130%.

7. Product according to anyone of the preceding claims, characterized in that the yams comprise at least 75% by weight, advantageously more than 85% by weight, preferably more than 95% by weight of basalt fibers.

8. Product according to anyone of the preceding claims, characterized in that the two opposite faces of the fabric are coated with a primer layer and with a silicone elastomer coating layer.

9. Product according to anyone of the preceding claims, characterized in that the silicone elastomer coating a face of the fabric has a maximum coating weight of

100g/m², advantageously of less than 80g/m².

10. Product according to anyone of the preceding claims, characterized in that the silicone elastomer coating layer comprises at least 50% by weight of silicone elastomer, advantageously at least 75%, preferably at least 85%.

11. Product according to anyone of the preceding claims, characterized in that the basalt fibers comprises continuous basalt filaments having a diameter comprised between 5 μm and 25 μm, preferably between 7μm and 2 lμm, and in that the yams have a weight comprised between 50 and 4000 tex, advantageously comprised between 100 and 2500tex, preferably lower than 500 tex.

12. Product according to anyone of the preceding claims, characterized in that at least a portion of a coated face with a silicone elastomer layer is provided with one or more further layers.

13. Product according to anyone of the preceding claims, characterized in that the portion of the fabric coated with a silicone elastomer layer has a porosity made of pores of less than 50μm, advantageously of less than 25μm, preferably of less than lOμm.

14. Product according to anyone of the preceding claims, characterized in that at least a portion of a coating layer comprises at least one or more compounds selected from the group consisting of luminescent compounds, fluorescent compounds, phosphorescent compounds, pigments, metallic pigments, coloring pigments, and mixtures thereof.

15. Product of anyone of the preceding claims, characterized in that at least a face of the coated fabric is associated with a heat insulating layer.

16. Product of anyone of the preceding claims, in which the primer coating is directly applied on the basalt fibers, characterized in that the primer coating and the silicone elastomer coating are selected so as to have a fire resistance corresponding to M0 according to the noπns NF P 92-503 : 1995, NF P 92-507 : 1997 and a smoke generation F0 according to the norms NF X 10-702-1 : 1995; NF X 10-702- 3 : 1994 and NF X 70-100 : 1986 .

17. Element comprising at least a product according to anyone of the preceding claims, in which advantageously at least a portion of the product is sewn with another portion of the product or with another product of anyone of the preceding claims or with another fabrics or layer or sheet.

18. Process for the preparation of a product according to anyone of the claims 1 to 16, characterized in that a basalt containing fabric is coated at least partly with a primer composition suitable for silicone elastomer, whereby the fabric coated with the primer composition is overcoated with an aqueous dispersion of a silicone elastomer, said aqueous dispersion containing at least 10%o by weight silicone elastomer, advantageously from 20 to 70% by weight, preferably from 30 to 50% by weight silicone elastomer.

19. Use of a product according to anyone of the claims 1 to 16, as fire protection layer.

20. Fire protection clothes, fingers, boots, mittens, gloves, cowls, helmets, comprising at least a product of anyone of the claims 1 to 16.