Sealant products have two basic functions: binding and making joints water-and airtight. In a joint, the sealer forms a barrier that stops certain substances or materials such as water, dust, dirt or wind from getting through. Joints are sealed either for insulation purposes or to withstand the contraction or expansion movements of any material.
The surfaces that require sealing. The choice of a sealant depends a great deal on the two materials that must be insulated/sealed. There are specific products that guarantee optimum qualities of the product on different materials such as concrete, glass, wood, marble, and aluminium, etc. Choosing the right sealant guarantees that the product will adhere to and be compatible with the medium upon which it is applied.
Environmental conditions. To choose the product type it is important to consider the climate and the temperature to which the joint is to be exposed and whether it is to be applied indoors or outside.
The conditions in which the joint is to work and whether the sealed joint must withstand a lot of contraction or expansion movements.
Characteristics of solicone sealants
- They do not break.
- Their movement capacity is extremely high.
- They are stable when they age (minimum of 10 years) and when exposed to extreme weather conditions and ultraviolet rays.
- They cure very quickly.
- They are ready for use (they do not need be mixed with any other products).
- They are resistant to chemical ageing.
- They are permeable to gas and to steam.
- They have non-stick properties.
- They are non-toxic.
Characteristics of acrylic sealants
- Paintable after curing.
- Weak toxicity (they are non-toxic).
- For low-movement joints in construction (movement <10%).
- Plastoelastic products.
- They may be transparent or coloured.
- They are single-component products and are ready for use.
Characteristics of polyurethane filler
- The product contains no solvents.
- It does not contain halogenated compounds.
- Low volume contraction.
Characteristics of polyurethane foams
- These are two-component products that comprise two reagents: isocyanate and polyol.
- They expand in contact with environmental moisture.
- There are two basic types: high-expansion and controlled expansion.
- They seal, insulate and fill.
- They must be applied at temperatures under 40ºC.