raw polymer component having a first melt viscosity and a second higher viscosity raw polymer component having a second melt viscosity is produced in a production step 7 with the second melt viscosity being greater than the first melt viscosity in the example of the blood bag 1 the two raw polymer components are two raw pvc components namely a suspension pvc component and another pvc component the two raw polymer components may also be components of the same polymer with different chain lengths the lower viscosity raw polymer component has a melt viscosity with a k value between 50 and 70 the higher viscosity raw polymer component has a melt viscosity with a k value between 60 and 100 the two raw polymer components are added in the production step 7 with a mixing ratio of 10 1 to 3 1 the ratios when mixing the two raw polymer components are selected such that a defined non homogeneous mixing of the raw polymer components takes place with the result that a heterogeneous mixture is obtained when the production step 7 is finished this heterogeneous mixture contains regions which consist almost exclusively of the first raw polymer component and regions which consist almost exclusively of the second raw polymer component after the second production step 7 the plastic compound is extruded in an extrusion step 8 when the mixture is extruded the surface structures 5 are produced as a result of the different melt viscosities of the two raw polymer components and the heterogeneity of the produced mixture since the components of the mixture consisting almost exclusively of lower viscosity raw polymer produce a.