F40 Dual Bond System. STYCCOBOND F40 is a solvent free synthetic polymer emulsion adhesive, developed to provide a peel-able bond for release underlays. It can also be used as a permanent or release bond adhesive when fixing carpets. It is water based and dries to form a transparent, permanently tacky coating. The type of bond achieved is dependent on when the floor covering is laid into the adhesive. Laying the floor covering into the adhesive once it has dried enables the underlay or carpet to be lifted when required, without significant damage to either floor covering or subfloor. Laying the floor covering into wet adhesive gives a permanent bond. It is suitable for use over normal underfloor heating installations. STYCCOBOND F40 can be used for securing a wide range of carpets which include those with felt, secondary, unitary and many other backings. It is also suitable for fixing certain release underlays which have been specifically developed for release bonding.