Method and device for producing a microfibrillated ceullose film

A device for producing a microfibrillated cellulose, MFC, film from an MFC dispersion, comprising:

• a support guiding device configured to guide a continuous support,
• a casting device configured to apply an MFC dispersion as a wet MFC film on the continuous support,
• a drying arrangement configured for removing a dispersing medium from the wet MFC film so as to form a dry MFC film,
• at least one measuring arrangement configured for providing data indicative of a dry solids content in the wet MFC film, or in the dry MFC film, or both at at least two data points which are laterally spaced across at least a width of the MFC film, and
• a controller, configured to receive said data, and to control the drying arrangement based on said data, so as to vary drying conditions across a width of the wet MFC film.

A microfibrillated cellulose, MFC, film having a longitudinal direction, which is parallel with a production direction of the MFC film and a width direction, which is perpendicular to the longitudinal direction,

• the MFC film having a film forming component content of at least 80-99.9% by weight,
• the film forming component comprising at least 50% by weight MFC,
• the MFC film having a width of about 0.3-4 m,
• the MFC film having a dispersing medium content of about 0.1-20% by weight, and
• the dispersing medium content of the MFC film having a standard deviation which is less than 1% by weight along the width direction,
• wherein a moisture content is analyzed for each cm of MFC film width.