Building sealant is mainly used to seal the gaps and holes, and to prevent gas, liquid, solid from entering, or to stop the construction materials being destroyed when moving. It also features heat preservation, sound insulation, waterproof dust prevention, gas prevention, fireproof, anticorrosion and shock absorption, and prevents gaps accumulating foreign bodies as well.
The categories of building sealant:
(1) Classify through composition: polysulfide rubber, chloroprene rubber, acrylic acid, polyurethane, butyl rubber, silicone rubber, rubber and plastic composite and thermoplastic elastomer,etc.
(2)Classify through coating ways: heat coating, cold coating, curing reaction type and solvents volatilizing type,etc.
(3) Classify through purposes: used for doors and windows, waterproof, shock absorption, or to seal gaps, and precast walls.
The methods to select right sealants:
(1) Good low permeability;
(2)Good filling performance;
(3)Compatible with gap substrates, no pollution, stable bonding;
(4) Cohesive failure will not happen in the stress and deformation;
(5)In the working temperature, it doesn’t excessively deform, or become hard and fragile, or isn’t soft and tacky.
(6) Resistant to ageing, weather, reasonable service life;
(7) Placement conforms to requirements;
The factors impact the properties of building sealants:
(1)Become aging in the sunlight and UV radiation;
(2)Oxygen and ozone oxidation;
(3)Water and vapour;
(5)Shear strength and wind load;
(6) Cycling and mechanical loading(compression,streching);