Formed of polysulphide rubber, polyurethane, silicone or some butyl
rubbers.Applications ~- Polysulphide ~ fac ̧ades, glazing, fire protection, roads and
paving joints. High modulus or hardness but not completely
elastic. - Polyurethane ~ general uses, fac ̧ades and civil engineering.
Highly elastic and resilient to abrasion and indentation,
moderate resistance to ultra-violet light and chemicals. - Silicone ~ general uses, fac ̧ades, glazing, sanitary, fire
protection and civil engineering. Mainly one part but set
quickly relative to others in this category. Highly elastic and
available as high (hard) or low (soft) modulus.
Two part ~ polysulphide and polyurethane based sealants are
often used with a curing or vulcanising additive to form a synthetic
rubber on setting. After the two parts are mixed the resulting
sealant remains workable for up to about 4 hours. It remains
plastic for a few days and during this time cannot take any
significant loading. Thereafter it has exceptional resistance to
compression and shear.One part ~ otherwise known as room temperature vulcanising
(RTV) types that are usually of a polysulphide, polyurethane or
silicone base. Polysulphide and polyurethane cure slowly and
convert to a synthetic rubber or elastomer sealant by chemical
reaction with moisture in the atmosphere. Generally of less
movement and loading resistance to two part sealants, but are
frequently used in non-structural situations such as sealing around
door and window frames, bathroom and kitchen fitments.Other sealants ~- one part acrylic (water based) RTV. Flexible but with limited
elasticity. Internal uses such as sealing around door and
window frames, fire protection and internal glazing. - silane modified polymer in one part RTV or two parts. Highly
elastic and can be used for general applications as well as for
fac ̧ades and civil engineering situations.
Sealants