What is a Sealant?
Sealant is basicly an insulating and grouting material. They can have ±25% movement capability. The flexibility ratio can be further increased as required. It is used for sealing, filling gaps, keeping water and air away from joints, absorbing the natural movements of building materials and increasing aesthetics. Silicone and polyurethane are two popular sealant types. Despite their common characteristics, there are significant differences between them.
What is the Basic Differences between Silicone & Polyurethane Sealants?
The main difference is at the chemical level. Polyurethane is an organic material. Silicone is an inorganic material. Polyurethane sealants; properties such as hardness, adhesion strength, thixotropy and flexibility can be easly manupulated according to need. Its mechanical strength and adhesion strength can be increased to very high levels compared to silicon.
In order to understand how a sealant performs outdoors, it is important to look at its resistance to sunlight. In the presence of UV light, an organic material, polyurethane, begins to return to its original polymer form. It deteriorates by losing its properties over time. But silicone, an inorganic material, this does not happen thus provides high UV resistance. However, Akfix polyurethane construction sealant has maximum UV resistance with the help of some special additives and does not deteriorate in any way and even shows a high level of resistance to color change.
Polyurethane Sealants Used for Sealing Purposes
Shore A hardness up to 45 polyurethane sealants are classified as low modulus. It is used in joints between prefabricated building elements, in joints of rainwater collection pipes on roofs and in rain gutters, insulating joints between precast concrete blocks and sealing of joints of aluminum pipes in HVAC (ventilation) sector.
Polyurethane sealants are available in the market with the following names; Polyurethane construction sealant, polyurethane sealant, non-staining polyurethane sealant, UV resistant PU sealant, bubble-free polyurethane sealant and modified silicone sealant.
Polyurethane Sealants Used for Bonding purposes
Polyurethane sealants with Shore A hardness of 45 and above are referred to as adhesive sealants. They have high surface adhesion and low flexibility. Especially in automotive industry used in the manufacture of vehicles, in the repair of auto glass, in the sealing of metal structures such as containers and trucks, in the manufacture and installation of air conditioning in HVAC systems, in order to reduce vibration and provide sealing in metal sheet joints.
Names commonly used in the market; Polyurethane adhesive sealant, extra strong polyurethane sealant, Premium polyurethane sealant, PU auto glass adhesive, PU metal adhesive, PU glass adhesive and PU marine adhesive.