Aramid fibers

Aramidfasern

Aramid fibers are a class of heat-resistant and strong synthetic fibers. They are used in aerospace and military applications, for ballistic-rated body armor fabric and ballistic composites, in bicycle tires, marine cordage, marine hull reinforcement, and as an asbestos substitute. The name comes from "aromatic polyamide". The chain molecules in the fibers are highly oriented along the fiber axis. As a result, a higher proportion of the chemical bond contributes more to fiber strength than in many other synthetic fibers.

An aramid fiber is a manufactured fiber in which the fiber-forming substance is a long-chain synthetic polyamide in which at least 85% of the amide linkages, (−CO−NH−) are attached directly to two aromatic rings. There are two types of aramid fibers namely meta-aramid fibers and para-aramid fibers, with the latter being superior in terms of technical performances.

 

Market

Global aramid fiber capacity has approached 130kt mostly distributed in North America, Europe, and Asia. Para-aramid fibers, accounting for about 63% of total global aramid fiber capacity, are primarily used in protection materials, high temperature resistant materials, and rope/optical cable; while meta-aramid fibers are mostly used in insulation, flame resistance, and filtration fields.

 

Manufacturing

Aramids are generally prepared by the reaction between an amine group and a carboxylic acid halide group. The most well-known aramids (Kevlar, Twaron, Nomex, New Star and Teijinconex) are AABB polymers. Nomex, Teijinconex and New Star contain predominantly the meta-linkage and are poly-metaphenylene isophthalamides (MPIA). Kevlar and Twaron are both p-phenylene terephthalamides (PPTA), the simplest form of the AABB para-polyaramide. PPTA is a product of p-phenylene diamine (PPD) and terephthaloyl dichloride (TDC or TCl).

Production of PPTA relies on a co-solvent with an ionic component (CaCl2) to occupy the hydrogen bonds of the amide groups, and an organic component (N-methyl pyrrolidone (NMP)) to dissolve the aromatic polymer. After production of the polymer, the aramid fiber is produced by spinning the dissolved polymer to a solid fiber from a liquid chemical blend. Polymer solvent for spinning PPTA is generally 100% anhydrous sulfuric acid (H2SO4).

 

GAB Neumann’s process equipment

The aramid fibers manufacturing process involves the recovery (absorption and further processing) of very large amounts of hydrochloric acid (HCl) therefore the need for corrosion resistant process equipment.

The dissolution of (PPTA) aramid fibers involves the use of concentrated sulfuric acid and therefore the potential need for silicon carbide process equipment.

GAB Neumann supplies annular groove graphite heat exchangers or graphite block heat exchangers, graphite heaters, graphite coolers, graphite absorbers, graphite columns and HCl recovery units as well as silicon carbide heat exchangers to the aramid fibers producers.

 


Associated products:

Impervious graphite annular groove interchangers

Impervious graphite annular groove heavy-duty condensers

Impervious graphite annular groove partial condensers

Impervious graphite block heat exchangers

Impervious graphite annular groove isothermal absorbers

Impervious graphite columns

Hydrochloric acid recovery units

Silicon carbide shell and tube heat exchangers

Silicon carbide block heat exchangers

Silicon carbide plate heat exchangers

GAB Neumann GmbH

Alemannenstrasse 29

79689 Maulburg

Germany

Tel: +49 (7622) 6751 0

Fax: +49 (7622) 6751 20

info@gab-neumann.de

GAB Neumann GmbH | Alemannenstrasse 29 | D-79689 Maulburg | Phone +49 (7622) 6751 0 | Fax +49 (7622) 6751 20 | E-Mail info@gab-neumann.de | www.gab-neumann.com