FR2808538A1 - THERMAL INSULATION MATERIAL - Google Patents

Abstract

Process for manufacturing a thermal insulation material in which yarns obtained from a synthetic aramid yarn and a preoxidized synthetic yarn are used, these yarns being cracked to obtain fibers which are mixed and spun, said method being characterized in that a sliver is produced from several of these threads, said sliver being knitted to obtain said material.

Description

The present invention relates to an insulation material

thermal tion.

  There is known a material constituting a firebreak which is in the form of a sheet produced from a wire formed from two synthetic materials, aramid and pre-oxidized, the wires being cracked, mixed, spun.

and knitted.

  The sheet thus obtained has relatively large holes formed by meshes and which, thanks to the down formed by the cracking operation, traps a certain amount of air which constitutes insulation.

  natural thermal slowing the conduction of heat.

  This down also forms an optical filter, the cut-off wavelengths of which correspond to those of the rayon.

  thermal emission spectrum of a fire flame.

  This fabric is light, easy to use and constitutes a fire barrier reducing the radius.

flame front.

  Such a fabric, however, lends itself poorly to the

  production of thermal insulation coatings.

  One of the aims of the present invention is, starting from a thread used for the manufacture of fabric

  flame arrester, to produce a fabric capable of constituting a coating for the thermal protection of organs or devices.

  The invention relates to a process for the manufacture of a thermal insulation material in which stubborn yarns are used from a synthetic aramid yarn and a preoxidized synthetic yarn, these yarns being cracked to obtain fibers which are mixed and spun, said method being characterized in that a wick is produced from several of these threads, said wick

  being knitted to obtain said material.

  The invention also relates to the material obtained according to the above process and which is of the type produced

  from a synthetic aramid yarn and a synthetic yarn

  preoxidized tick, these threads being cracked and the fibers thus obtained mixed and spun, said material being characterized in that it consists of a wick made

  from several of these threads, the wick being knitted.

  We thus obtain a knitted fabric, flexible, light, which has a certain volume and which finds a particularly interesting application for covering materials.

protect from heat.

  Preferably, the wick is formed of at least

  four threads knitted on a lace-making machine.

  Preferably, the wick has a size of

N.M. 2.8.

  Finally, the wick is knitted on a loom

garnished with large needles.

  The invention will now be described in more detail with reference to an embodiment.

  particular given by way of example only.

  The insulation material is formed from fibers made from a synthetic aramid yarn known commercially under the name "KEVLAR" and from a preoxidized synthetic yarn known commercially under the name

of "SIGRAFIL 0".

  These threads are produced in a continuous form, the synthetic aramid thread being light and having qualities of mechanical resistance, while the thread

  synthetic pre-oxidized is thermally stabilized, non-inflammable

mable and does not melt in the heat.

  The wires are subjected to a cracking operation in order to stretch them until they break to obtain

  fibers having lengths between 60 mm and 200 mm.

  The fibers are mixed in the proportion of 70% of fibers of the pre-oxidized synthetic yarn and of 30%

  fibers of synthetic aramid yarn.

  A spinning is then carried out to obtain a wire which, on the one hand, resists heat and, on the other

  hand, is mechanically resistant.

  This thread thus obtained has, on its surface, fibrules which constitute a down and form a network.

reflective elements.

  From this thread, a lock is formed by knitting several of these threads, for example, four on a lace-making machine. The wick thus obtained

  has a thickness of N.M. 2.8 (i.e. 2800 m for one kilo).

  This wick has loops that contain air trapped between the fibrils.

  The lock obtained is knitted on a loom with large needles (gauge 2 to 6) and a knitted fabric is obtained which has a certain thickness.

  and a certain volume of air and which lends itself perfectly to the thermal protection of parts or devices, for example of liquefied gas tanks.

  Of course, the invention is not limited to the embodiment which has just been described and represented.

  you. Many modifications of detail can be made without departing from the scope of the invention.

Claims (5)

  1. Process for manufacturing an isolate material   thermal tion in which yarns obtained from a synthetic aramid yarn and a preoxidized synthetic yarn are used, these yarns being cracked to obtain fibers which are mixed and spun, said process being characterized in that '', a wick is made from several of these threads, said wick being knitted to obtain said material.   2. Thermal insulation material produced according to the method of claim 1 and of the type produced   from a synthetic aramid yarn and a synthetic yarn   preoxidized tick; these threads being cracked and the fibers thus obtained mixed and spun, characterized in that   that it consists of a wick made from more   of these threads, the wick being knitted.   3. thermal insulation material, according to claim 2, characterized in that the wick is formed of at least four son knitted on a manufacturing machine shoelaces.   4. Thermal insulation material, according to   claims 2 and 3, characterized in that the wick at a thickness of NM 2.8.   5. Thermal insulation material, according to   Claims 2 to 4, characterized in that the wick is   knitted on a loom filled with large needles (gauge 2 to 6).