Fill gaps and cracks with sealants
Sealants are essential in construction and reparation in filling gaps, voids, joints and cracks. Different types of sealants are available depending on the type of construction; they may be flexible or rigid; non-sagging or self-levelling. Sealants form seal gaskets, strips or glands between panels or tiles. They are used for example in glazing, dilatation, roofing, swimming pools and facade constructions.
Get to know the sealants types and choose the most suitable one
The difference between types of sealants can be made by application purposes or resin types. The most common sealant type is silicon. Its popularity derives from its ability to endure UV radiation better than any other sealant. Nonetheless, silicon has also downsides; it is not compatible with paint thus the appearance remains what it is. Other sealant types include for example:
- Polyurethane sealant
- Hybrid sealant
- Acrylic sealant
- Silicone sealant
- Bituminous and butyl sealants
Silicon polymers form the basis for silicon sealant which has a flexible rubber-like structure when cured. Most of the silicon seals are waterproof and suitable for both inside and outside applications. Besides being waterproof, silicon is also resistant to UV light and temperature changes do not affect it, which makes it more suitable for exterior applications than other sealing products. A standard silicon sealant withstands temperatures from -40°C to +180°C without difficulties. Silicon sealant can be applied on for example in bathrooms, facades and glazing.
Sometimes seals also have an aesthetic function; then colour plays an important role. As silicon sealant is not compatible with paint, another option needed to be developed; painting acrylic sealant is possible, and the result can be very good with optimal product compatibility. Various types of Hybrid sealant share the paintability and flexibility characteristics in one product. However, it is still necessary to make sure that the paint and sealant are compatible with each other! Acrylic sealants face limitations in movement capability. Depending the quality up to 12,5% where silicone and hybrids go t up to 25% and higher.
Compatibility with paint and coatings
Sometimes sealants are painted but just as often sealant is applied on paint. Therefore, it is of high importance to control the compatibility of the paint and sealant before applications. An incompatible pair of coatings can lead to significant costs in terms of surface failure and re-application. Not only is controlling compatibility crucial, but also the binder balance of the paint.
What happens when paint and sealer are not compatible?
Depending on the coatings, incompatibility can cause problems and lead to failure in terms of looks and function.
- Migration between the sealant and paint leading to discolouring
- Efflux; the paint does not flow as it should on the surface, which leads to unequal coverage
- Slow drying process or no drying at all, when the paint remains sticky and attracts dirt and dust.
- Darkening colour due to bleeding of plasticisers
When it comes to compatibility, the developers are continuously faced with new challenges due to the rapid developments of coatings and changes in regulations. Siroflex (from Den Braven) for example is concerned with the compatibility problems and ever developing products; therefore, Siroflex offers a range of UCA (Unique Compatibility Additives) sealing products. Over-coating these products is possible and it is also tested with a wide range of products. The newest innovation in the world of sealants is a product which allows over-coating right after application with little risk of cracking and bleeding. For example Siroflex Instant Paintable Acrylic is such a product.
Adhesives for joining surfaces
In general adhesives refer to substances which bond surfaces or objects together. For example glues are adhesives. Adhesives can be used for joining surfaces of one material type or joining different materials; for example plastic with metals. Adhesives can be solvent borne or solvent free and they have different properties depending on the use.
The most common types of adhesives include:
- PVA (polyvinyl acetate): a general purpose glue for wood work. Water resistance of these products vary per product; for exterior application it is thus crucial to control whether the adhesive is waterproof. PVA is also suitable as a sealant and cement admixture.
- Synthetic resin: a strong glue bonding adhesive for wood work. These resins are always waterproof and therefore, ideal for outside applications. The product is very fast curing; application must thus take place immediately after mixing the components.
- Epoxy resins: a glue -like waterproof joining adhesive for metals and plastics. Epoxy systems usually consist of two components which cure fast; the application must thus take place immediately after mixing the components.
- Contact adhesive: ideal for joining polystyrene and fabrics. Also useful for fixing plastic laminates to a wooden base.
- Acrylic cement: suitable for joining acrylic and some other types of plastics. The adhesive “melts” the surface of the plastic and fuses it together.
- PU adhesives: stick to most materials and is suitable for bonding different material together; it successfully bonds non porous materials such as metals to wood or mirrors to walls.
2 in 1 – Hybrid adhesive sealants
Bonding and joining are the main purposes of adhesives; these characteristics are also beneficial for sealants. Therefore hybrid adhesive sealant products exist. The hybrids are additionally, easy to apply single component systems which do not contain isocyanates. The hybrid adhesive sealants exist as consumer and industrial products. They are applicable for example in refridgerated trailers, truck bodies, ship building as well as ventilation and air conditioning units.
The hybrid technology allows development of extremely water resistant, hydrophilic, durable products which are not affected by UV light. They are also environmentally friendly due to the fact that they have low or zero VOC content. There are various adhesive sealants suitable for interior and exterior applications.
For example Siroflex from Den Braven offers such products and other adhesives in the UK. Both, consumer and industrial products are available.