What is Twaron?


Twaron is the brandname of Teijin Aramid for a para-aramid. It is a heat-resistant and strong synthetic fibre developed in the early 1970s by the Dutch company AKZO, division ENKA, later Akzo Industrial Fibres. The research name of the para-aramid fibre was originally Fiber X, but it was soon called Arenka. Although the Dutch para-aramid fibre was developed only a little later than DuPont’s Kevlar, introduction of Twaron as a commercial product came much later than Kevlar due to financial problems at the AKZO company in the 1970s.

History

This is a chronology of the development of Twaron:

  • In 1960s a research program starts for “Fiber X.”
  • In 1972 the ENKA Research laboratory develops a para-aramid called Arenka.
  • In 1973 Akzo decides to use sulfuric acid (H2SO4) as a solvent for spinning.
  • In 1976 a pilot plant is built.
  • In 1977 first production starts.
  • In 1984 the product is renamed Twaron.
  • In 1986 commercial production is started at five locations and nine plants.
  • In 1987 Twaron is introduced as a commercial product.
  • In 1989 the aramid business of Akzo becomes an independent Business Unit called Twaron BV.
  • Since 2000 Twaron BV is owned by the Teijin Group, now called Teijin Twaron BV and based in Arnhem, The Netherlands. The main production facilities for Twaron are in Emmen and Delfzijl.
  • In 2007 Teijin Twaron expands for the fourth time in six years and also changes its name into Teijin Aramid.

Production

Polymer Preparation

Twaron is a p-phenylene terephtalamide (PpPTA), the simplest form of the AABB para polyaramide. PpPTA is a product of p-phenylene diamine (PPD) and terephtaloyl dichloride (TDC). To dissolve the aromatic polymer Twaron used a co-solvent of N-methyl pyrrolidone (NMP) and an ionic component (calcium chloride CaCl2) to occupy the hydrogen bonds of the amide groups. Prior to the invention of this process by Leo Vollbracht, working at the Dutch chemical firm AKZO, no practical means of dissolving the polymer was known. The use of this system by DuPont led to a patent war between AKZO and DuPont as Dupont initially used the carcinogenic HMPT (hexamethylphosphoramide). Despite heavy research DuPont now also uses the AKZO patent to use the less hazardous NMP in the Kevlar process.

Spinning

After the production of the Twaron polymer in Delfzijl, the polymer is brought to Emmen, where fibres are produced by spinning the dissolved polymer into a solid fibre from a liquid chemical blend. Polymer solvent for spinning PPTA is generally 100% anhydrous (water free) sulfuric acid (H2SO4). The polymer is dissolved by mixing frozen sulfuric acid in powder form with the polymer in powder form and gently heating the mixture. This process, which differs from the more difficult DuPont process, was invented by Henri Lammers and patented by AKZO.

Industrial Uses

Twaron is a para-aramid and is used in automotive, construction, sport, aerospace, military and industry applications, e.g., “bullet-proof” body armor, fabric, and as an asbestos substitute.

Protective gear (heat resistant / ballistics)

flame-resistant clothing, protective clothing and helmets, cut-fast or heat-hardy gloves, sporting goods, textiles, ballistic vests

Composites

composite materials, technical paper, asbestos replacement, hot air filtration, sailcloth, speaker woofers, boat hull material, fibre reinforced concrete, drumheads

Automotive

brake pads, turbo hoses, V-belts and Timing belts, tires that incorporate Sulfron (sulfur modified Twaron), mechanical rubber goods reinforcement

Linear tension

optical fiber cables (OFC), ropes, wire ropes, cables, umbilical cables, electrical mechanical cable (EMC), reinforced thermoplastic pipes

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