Cupro ( Abbr: CUP), also copper or copper silk fiber is composed of a Celluloseregeneraten textile fiber. The properties of cupro are comparable to viscose. Cupro fibers are processed mainly for animal feed materials, because they are breathable, hygroscopic and invite to non- static. In addition, the materials have a silky soft feel and are smooth and shiny. Cupro can be washed and ironed, but not iron.
Already in 1857 the Zurich chemistry professor Mathias Eduard Schweizer ( 1818-1860 ) had found that cellulose can be dissolved in aqueous ammonia ( Schweizer's reagent ) in a solution of copper ( II ) hydroxide. As the beginning of the technical use of this observation, the French Patent No. can be viewed from 203 741 in 1890 by Louis -Henri Despaissis. Because of the early death of the inventor, there were no commercial exploitation of the invention. 1897 reported the chemist Max Fremery and the engineer Johann Urban its proceedings, be made of such liquefied cellulose fibers, for a patent. Fremery and Urban used these copper rayon threads though initially only as filaments in their 1892 light bulb factory opened in Upper fracture in Aachen (city Heinberg ). After further refinement, they were finally in 1899, able to produce with their method also useful copper rayon yarns for the textile industry, and so ( a district of Wuppertal since 1929 ) was on September 19, 1899 in Elberfeld founded the United Glanzstoffabriken AG whose main plant was more at home in upper fracture in Aachen. The most important market of copper rayon was the bergische stocking industry.
In parallel, began in 1900 in Wuppertal- Barmen development work necessary to cuprammonium silk production of the JP Bemberg AG, as its raw material from 1908 served the Linter -called non -spinnable short seed hairs of cotton seeds. A new, by Edmund Thiele 1901 at the J. P. Bemberg developed stretch-spinning method nevertheless made it possible to produce from this raw material, a yarn - known as Bemberg silk - corresponded to its fineness of natural silk and also still had a greater strength than viscose rayon.
1902 closed Fremery and Urban then their Glühlampenfabrik to devote himself mainly of artificial silk production. Quickly recognized both the future potential of artificial silk, and so they bought 1910/1911 first, the " Prince Guido Donnersmarckschen rayon and Acetatwerke " in Sydowsaue at Stettin (now Szczecin Żydowce, Poland), and then their Viscosepatente to perfect it further.
As feed material for the manufacture of outerwear and accessories for was very popular cupro long time. For cost and environmental reasons, however, it is now no longer manufactured in Germany and replaced with viscose or other fibers. In imported fabrics but cupro can still occur.
Until the 1980s Cuprophan was the most common material, which was used as a membrane material in dialyzers for extracorporeal dialysis. Today this especially synthetic materials with improved biocompatibility such as polysulfone are used.
Cuprous copper oxide is prepared by the ammonia process ( cuprammonium process). In this process, cellulose is dissolved in an ammoniacal solution of Tetraamminkupfer (II ) hydroxide. The result is a viscous solution containing 4 % copper, 29 % ammonia and 10% cellulose contains. If this liquid is pressed through spinnerets into warm water flowing quickly, the cellulose obtained as a very fine thread out ( stretch-spinning method ). The copper ions are removed through ion exchange and washed the fibers with dilute sulfuric acid.