The new explosive was widely exported, notably to the government of North Vietnam, which received 14 tons during the Vietnam War. There are visual differences between Semtex and other plastic explosives, too: while C-4 is off-white in colour, Semtex is red or brick-orange. Semtex was very similar to other plastic explosives, especially C-4, in being highly malleable but it is usable over a greater temperature range than other plastic explosives, since it stays plastic between −40 and +60 ☌. The plant was later renamed to become Explosia a.s., a subsidiary of Synthesia. The explosive is named after Semtín, a suburb of Pardubice where the mixture was first manufactured starting in 1964. Semtex was invented in the late 1950s by Stanislav Brebera and Radim Fukátko, chemists at VCHZ Synthesia, Czechoslovakia (now Czech Republic). Plasticizers: n-octyl phthalate, tributyl citrate The H (or SE) variant is intended for explosion hardening. The versions 1AP and 2P are formed as hexagonal booster charges a special assembly of PETN and wax inside the charge assures high reliability for detonating cord or detonator. The 1A (or 10) variant is used for mining, and is based mostly on crystalline PETN.
The composition of the two most common variants differ according to their use.
