Thin film evaporator, and method for producing a transfer mixture

The invention relates to a thin film evaporator (D) for producing a transfer mixture according to the direct dissolution method, comprising a feed (1), a housing (4) and an outlet (2), wherein the feed (1) introduces a starting material, made of cellulose, water and a functional fluid, into the housing (4), wherein an evaporator shaft (5) situated in the housing (4) rotatingly sweeps the starting material over the heated interior of the housing (4), wherein the product is heated and some of the water evaporated so as to result in the transfer mixture, which flows to the outlet (2) together with a supply stream, wherein the through-flow capacity of the outlet (2) is greater than the supply stream.