Twaron is a heat-resistant and strong synthetic fiber developed in the early 1970s by the Dutch company AKZO, division Enka, later Akzo Industrial Fibers. The research name of the para-aramid fiber was originally Fiber X, but it was soon called Arenka. Although the dutch para-aramid fiber was developed only little later than DuPont's Kevlar, its introduction was much later due to financial problems at the AKZO company in the 1970s. A short overview of the history of Twaron:
- In 1960s start of research program for Fiber X.
- In 1972 the ENKA Research laboratory had developed a para-aramid called Arenka.
- In 1973 Akzo decided to use sulphuric acid (H2SO4) as a solvent for spinning.
- In 1976 a pilot plant was built. First production in 1977.
- In 1984 the product was renamed Twaron.
- In 1986 commercial production was started on 3 locations and 9 plants.
- In 1987 Twaron is introduced as a commercial product.
- In 1989 the aramid business of Akzo became 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 en Delfzijl.
- In 2007 Teijin Twaron is expanding for the fourth time in six years  and also changes its name into Teijin Aramid.
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 (hexamethyl fosfortriamide). Despite heavy research DuPont now also uses the AKZO patent to use the less hazardous NMP in the Kevlar process.
After the production of the Twaron polymer in Delfzijl, the polymer is brought to Emmen, where fibers are produced by spinning the dissolved polymer into a solid fiber from a liquid chemical blend. Polymer solvent for spinning PPTA is generally 100% (water free) sulphuric acid (H2SO4). The polymer is dissolved by mixing frozen sulphuric 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.
Major industrial uses
- Protective Gear (Heat Resistant / Ballistics):
- Linear Tension:
- Year of Twaron. "Twaron - A history of innovation" (PDF). Twaron News (June 2007): 10–11.
- International Fiber Journal (2007). "Teijin Launches Fourth Production Expansion in Six Years". Fiber Journal (February): 20.
- JWS Hearle. High-performance fibres. Woodhead Publishing Ltd., Abington, UK - The Textile Institute. ISBN 1855735393.
- Doetze J. Sikkema (2002). "Manmade fibers one hundred years: Polymers and polymer design". J Appl Polym Sci, John Wiley & Sons, Inc. (83): 484–488.
- L. Vollbracht and T.J. Veerman, US Patent 4308374 (1976)