Process and apparatus for applying liquid, pasty or foamy substances to both sides of webs of material

A process for applying liquid, pasty or foamy substances on both sides of a web of material, comprising the steps of:

• moving a web along a given direction;
• disposing applicator rolls on both sides of the web with one immediately behind the other along the given direction and in contact with one surface thereof such that the web is supported on only one surface at each application roll and the web is guided substantially straight therethrough;
• adjusting the layer thickness directly on the applicator rolls;
• drying the web in a suspension drier only after both coatings;
• and
• wherein the applicator rolls are spaced apart at a predetermined distance for the speed of the web such that the time during which a substance is applied at a first roller and a substance is applied at the second roller is not sufficiently long to impregnate the web of material and substantially reduce the strength of the web of material.