F

Filler
Solid compounding material, often inert and usually in finely divided form, which may be added in relatively large proportions to a polymer to improve properties and/or decrease cost.
Syn. Extender

Fisheyes
Relatively small deformations (pock marks) in the adhesive. Can be caused by oily spots or silicone particles and/or by the entrapment of air between layers in the roll. Are not an indication of a quality defect.

Fixuring time
Amount of time before bonded parts can be handled. Fixturing time is often somewhat longer than green time .

Flame and smoke retardant
Additive which inhibits the initiation and/or spread of flame or smoke by inhibiting the combustion reaction in the flame, or by other mechanisms such as suppression of the oxygen flow and the build-up of protecting layers.

Fluorescent whitening agent
Syn. Optical brightener

Foam sealant
Foam sealant are used to filling, bonding, sealing and insulating joints, cracks and cavities. This kind of sealant are usually formulated with polyurethane- pre-polymers.

Fungi
Types of microscopic plant materials that are very numerous and occur in many different forms. Their spores, or reproductive bodies are everywhere and await only proper conditions of moisture and temperature to germinate, grow and reproduce.

Fungicide
Substance capable of destroying or preventing the growth of fungi. Fungicides do not provide any residual protection from future mould growth. See Preservative