Cupro is commonly known as a Japanese based developped material. - It is a kind of Rayon (Viscose ) group of Fibres.
It is more like Liocell , it is reprocessed cellulose. It is made from regenerated cellulose fiber .

Cuprammonium, gives the name to the fibre Cupro , it is used in making of process the wood pulp which is the base material. With the process, the wood pulp is dissolved in an ammoniac copper oxide solution.

Cupro fabric breathes like cotton, drapes beautifully, and feels like silk on your skin. Its slinky, curve-hugging drape makes it great for elegant dresses and blouses.

What is Cupro ? : Cupro is a regenerated cellulose fiber, soft, strong and silky, produced by treating cotton cellulose with cuprammonium salts. It is also called Cuprammonium Rayon. Cupro was first made in 1890s in Japan and Italy.
Trade names are used within the rayon industry to determine the type of rayon used: • BEMBERG, for example, is a trade name for cupramonium rayon that is only produced in Italy. • MODAL is a widely used form of rayon produced by Lenzing Fibers Corp. which is based in northern Austria. Galaxy, Danufil, and Viloft are rayon brands produced by Kelheim Fibres, a German manufacturer. • GRASIM (India) is the largest producer of rayon in the world (claiming 24% market share). -

Thanks To Sources: KMK MODA LTD, Mr. Kaan Karahan Interview ,Wikipedia.org., Mindfully.org ,MadeHow.com,www.imrsheep.com