FR2808814A1 - IMPROVEMENT IN THERMAL INSULATION MATERIALS - Google Patents

Abstract

Thermal insulation material of the type made from a synthetic aramid yarn and a pre-oxidized synthetic yarn, these yarns being cracked to obtain fibers which are mixed and spun, a number of yarns thus obtained being knitted to obtaining wicks, these wicks themselves being knitted to obtain said material, characterized in that the material (2) is coated, on at least one face, with a layer of an intumescent epoxy resin (3).

Description

The present invention relates to a thermal insulation material

  intended in particular for the protection of gas tanks and more particularly for

  tanks of vehicles running on gas G.P.L.

  In French patent application No. 00.05583 filed May 2, 2000, a thermal insulation material was proposed composed of fibers of a synthetic aramid yarn and fibers of a preoxidized synthetic yarn, these fibers being mixed and spun , said yarns thus obtained being knitted to obtain a wick, the wicks also being

knitted to obtain a fabric.

  After many tests, it was found that such a material withstands heat well but that the protection

  thermal for some applications was insufficient.

  The invention therefore aims to improve the qualities

  of thermal protection of said material above.

  The material according to the invention is produced from a synthetic aramid yarn and a preoxidized synthetic yarn; these yarns being cracked to obtain fibers which are mixed and spun, a number of yarns thus obtained being knitted to obtain wicks, these wicks being themselves knitted to obtain said material, said material being characterized in that it is coated on one side with at least one layer of resin

intumescent epoxy.

  Thanks to such an arrangement, if the object protected by said material is subjected to heat from a temperature threshold of the order of 100 C, the resin layer, by swelling, forms a protective mattress which increases d protection provided

by the knitted fabric.

  Preferably, the layer of intumescent epoxy resin is coated with a layer of intumescent paint. According to another detail, the thickness of the layer of

  intumescent resin is in the range of 2 to 7 mm.

  Preferably, the thickness of the paint layer

  intumescent is of the order of 0.3 to 0.10 mm.

  It is also possible to add to the material a sheet of knitted fabric formed from preoxidized synthetic threads and synthetic aramid threads, the latter having previously been cracked and spun, this additional ply possibly receiving a layer of

  intumescent resin and a layer of intumescent paint.

  The invention also relates to a process for producing thermal insulation using the material as defined above and characterized in that it consists in applying, to an object to be protected, said material and in projecting onto the external face of this one

  layer of intumescent epoxy resin.

  Finally, the invention also relates to objects

  thermally protected according to the process defined above.

  The invention will now be described in more detail with reference to particular embodiments given by way of example only and shown in the accompanying drawings, in which: Figure 1 is a schematic perspective view

  showing an object such as a tank to be protected.

  Figures 2, 3 and 4 are perspective views

  showing the installation of thermal insulation material.

  In Figure 1, an object such as a

  tank 1 of liquefied gas used for a vehicle.

  The reservoir 1 receives a first ply 2 of a knitted fabric produced from knitted wicks and formed of several threads, for example four, these threads being formed from a mixture of fibers obtained by cracking a first synthetic thread of aramid known in the trade under the name of "Kevlar" and of a second preoxidized synthetic yarn known in the trade under the name of "Sigrafil 0", these fibers being spun and the threads obtained

  being knitted in locks with a lace making machine.

  The sheet 2 is cut and folded to match an upper face of the tank and part of the height

side walls.

  On the sheet 2, a layer of an intumescent epoxy resin is sprayed, for example a resin known in the trade under the name of "Nullifire System E",

  the thickness of this resin being of the order of 5 mm.

  Such a resin which is deposited on a very thin layer has the advantage of withstanding high temperatures and, from a determined temperature threshold, of swelling so as to improve the thermal qualities of the sheet 2. The tank 1 is then turned over and a sheet 4 of the same material as said sheet 2 is applied to the face opposite to that coated with the sheet 2, the edges of the sheet 4 covering the edges of the sheet 2 and then

  sprays a resin 3 on this sheet 4.

  Next, a finishing layer of an intumescent paint is sprayed onto the assembly, the thickness of which is of the order of 0.70 mm. Such a painting is known and

  sold commercially under the name "Nullifire S 605".

  Such resins have the advantage of being able to be deposited in very thin layers and to swell when the heat reaches a temperature of the order of 100 C. As they do not burn, the increase in thickness

  provides additional thermal protection.

  It has been found, after numerous tests, that a tank thus protected and filled to 80% with a liquefied gas could resist a temperature of the order of 800 C for more than 40 minutes. The pressure inside the tank is kept at a level of around 25 bars, which means that the temperature inside the tank

  did not exceed a determined threshold.

  Two interlocking half-shells are thus produced which can easily be mounted on a tank of a vehicle and easily removed to allow verification

the state of said tank.

  In Figure 5, there is shown an alternative embodiment for the protection of a cylinder of

gas 6.

  In accordance with this embodiment, two half-shells are produced which fit into one another by enclosing the carboy 6, said half-shells each being formed from a ply 9 of the same type as the plies 2 and 4, the plies, on the exterior faces, being coated with a layer of an intumescent epoxy resin and possibly with a layer of finishing paint

intumescent.

  The invention can also be applied to the production of protective panels for tunnels, these partitions, etc. In Figure 6, there is shown a panel on one side of which is laid a sheet 11 of the same type as the sheets 2 and 4, the outer face being coated with a

  layer of intumescent epoxy resin 12.

  On said outer face, a ply 15 of a knitted fabric formed from preoxidized synthetic threads and synthetic aramid threads can be applied.

  these having previously been cracked and spun.

  This ply 15 optionally receives a layer of intumescent resin 16 and a layer of intumescent paint. It is possible to provide, for example, that a ply 15 is also affixed to the plies 2 and 4, the layer of intumescent paint then being sprayed onto said

tablecloth 15.

  Of course, the invention is not limited to the embodiments which have just been described and shown. Many detailed modifications can be made without departing from the scope of

the invention.

Claims (8)

  1. Thermal insulation material of the type produced from a synthetic aramid yarn and a preoxidized synthetic yarn, these yarns being cracked to obtain fibers which are mixed and spun, a number of yarns thus obtained being knitted to obtain wicks, these wicks being themselves knitted to obtain said material, characterized in that the material (2) is coated, on at least one face, with a layer of a resin intumescent epoxy (3).   2. Thermal insulation material according to claim 1, characterized in that the layer of intumescent epoxy resin is coated with a layer of intumescent paint. 3. Thermal insulation material according to claim 1, characterized in that the resin layer   intumescent is of the order of 2 to 7 mm.   4. Thermal insulation material according to claim 2, characterized in that the thickness of the intumescent paint layer is of the order of 0.3 to 0.10 mm.   5. Thermal insulation material, according to   claim 1 and / or any one of claims 2   4, characterized in that a material of a knitted fabric formed from preoxidized synthetic threads and synthetic aramid threads is added to the material, these having been previously cracked and spun, this additional ply possibly receiving a layer of '' an intumescent resin and a layer of intumescent paint. 6. A method of producing thermal insulation using a material such as that of claim 1   and / or any one of claims 2 to 4,   characterized in that it consists in applying, to an object to be protected, said material and in projecting, on the external face thereof, a layer of an epoxy resin intumescent.   7. A method of producing thermal insulation according to claim 5, characterized in that a layer of paint is sprayed onto the intumescent epoxy resin. intumescent.   8. Objects for which thermal protection is achieved   according to the method of claims 6 and 7.