Method for producing silicone multi-layer composites

A method for producing a multilayer silicone composite comprising at least two layers of cured silicone, each with a layer thickness of 0.1 to 200 and with a thickness precision of the silicone layers of ±5% as measured over an area of 200 cm2,

• by the steps comprising:
• i) applying a first solvent-containing or solvent-free, crosslinkable silicone composition through a slot of a first slot die to a moving carrier to form a first silicone layer,
• ii) subsequently removing the solvent, if present, from the first silicone layer which forms on the carrier film, and partially crosslinking the first silicone layer, such that the first silicone layer has a degree of crosslinking of at least 40% and at most 90%,
• iii) optionally applying one or more intermediate layers, to give a 1st layer composite, composed of carrier, a partially crosslinked first silicone layer, and optional intermediate layer(s),
• iv) applying a second solvent-containing or solvent-free, crosslinkable silicone composition through a slot of a second slot die to the moving 1st layer composite to form a second silicone layer, wherein the second solvent-containing or solvent-free crosslinkable silicone composition may be the same or different from the first solvent-containing or solvent-free crosslinkable silicone composition,
• v) subsequently removing the solvent, if present, from the second silicone layer which forms on the 1st layer composite, and partially crosslinking the second silicone layer such that it has a degree of crosslinking of at least 40% and at most 90%,
• vi) optionally repeating steps iii) to v) one or more times,
• vii) further crosslinking the silicone layers, and
• viii) subsequently optionally separating the resulting multilayer silicone composite from the carrier,
• with the following provisos:
• the slot dies in steps i) and iv) may be the same or different, and are at an angle of between 10° and 90° to the carrier;
• the travel speed of the carrier and of the 1st and also further silicone layer(s) in steps i) and iv) is between 0.1 and 1000 m/min;
• the dynamic viscosity at 25° C. of the solvent-containing or solvent-free crosslinkable silicone compositions, measured according to DIN 53019, is between 100 mPa·s and 1000 Pa·s,
• the surfaces of the carrier contain no depressions or elevations which are larger than 5% of the film thicknesses to be produced, and
• particles which are greater than ⅓ of the silicone layer thicknesses are removed from each solvent-containing or solvent-free crosslinkable silicone composition before it is applied.