FIBROUS MATTER RESISTING ACTION COMBINEE OF HEAT AND THE PRESSURE

ΐ

A-resistant fibrous material Ja the combined action of heat and pressure.

it presently exists a request important in the industry for fibers techniques that resist both high temperatures, of the order of 450 °C, and to the action of aggressive chemicals.

Uses, particularly in the field of seals, also elements impose high pressure resistant, of the order of 400 bar.

Currently, such seals are most often made of molded bodies in the expanded graphite, but this is a costly solution; there is also made of the sealing inserts of asbestos fibers, which results in problems of air pollution.

The present invention has been given to provide a novel fibrous material capable of withstanding high stresses pressure and temperature, and the corrosive action of many chemicals.

The fibrous material according to the invention is characterized in that it consists essentially of an intimate mixture of polybenzimidazole fibers and fibers of nickel based metal alloy.

Is used, preferably, the fibres obtained by cracking filaments produced by drawing of the nickel based metal alloy sold under the mark Inconel by the company International Nickel.

According to a preferred embodiment of the invention, the fibrous material consists essentially of about 70 % polybenzimidazoie fiber and fiber of about 30% nickel alloy.

A quantity of aromatic polyamide fibers aramid high modulus is advantageously added to the mixture according to the invention, to improve the mechanical properties. This amount is between 15% and 50% by weight calculated relative to the total weight of the mixture.

Polybenzimidazole The fiber is preferably produced by the cracking of filaments to a height of 110 mm average fiber. The fiber nickel alloy is also obtained by cracking wires drawn to an average height of 120 mm, the intimate mixing is carried out to a spinning for long fibers.

This transformation continuous filaments is made by a method for stretch breaking and controlled breaking; it is performed on multi-filament tows unitary fiber, whose titre is between 0.8 dtex and 6, as mentioned above. Therefore, long fibers, thereby spinning a very broad range of securities between 1/1 (lOOOtex) and 200/1 (5tex).

Is then performed the further steps of finishing, such as twisting or the wiring.

Nickel-based alloy, refractory material of very high chemical inertness, has never, so far, been used in the textile field, and that is its transformation into fibers by the cracking/drawing method which enables its use in the fibrous material according to the invention in high proportions quite surprising.

The fibrous material thus obtained has numerous applications.

Therefore, , in the form of braided and carded, it can be used as gland, in sealing gaskets capable of withstanding pressures up to 400 bar and temperatures up to 450 °C.

It also finds uses interest in the field of protective clothing against heat and chemicals.

It can also be used, in the form of a grating woven, as a protection, flexible or rigid thermal fluxes, support matrices.