Coating Systems

As legislation changes to control and reduce the level of hazardous chemicals and create risk free environments for end users, businesses need to react and ensure products not only meet but exceed the new demands. Sika R&D takes legislation and regulatory issues seriously, and reacts accordingly and always considers the impact of raw materials when formulating.

One issue affecting roof waterproofing performance coatings is the use of solvents in products. Whilst legislation has demanded a reduction in the overall level of solvent in roof coatings, there is no global norm. Some regions demand very low levels, for example, whilst others are not as stringent yet.

To address the issue and associated odour that accompanies solvents, R&D has developed a range of high performance waterproofing products for use on roofs and balconies. These are based on unique in-house latent hardeners, which when formulated into single component polyurethanes allow products with significantly lower levels of solvent. The lower level of solvent gives a reduction in the odour and reduced emissions to the atmosphere.

An example is Sikalastic 641, a low odour, roof waterproofing product. It rapidly becomes resistant to rain damage due to the latent hardener curing system. It is cold applied, eliminating the risk of fire, even in an occupied building during application and cures to form a completely seamless waterproofing membrane. The technology has now been expanded to give a platform of products which can be used on roofs, balconies and car park decks.

New amine hardeners give reduced yellowing during the service life of floors, no blushing even under harsh conditions and reduced emissions during application. The new amines will allow a platform of products to be developed ranging from a roller coat, self leveller, clear top coat and ESD solutions.

In combination with standard amines, the new solutions display unique properties. Sika developed a new epoxy platform and launched it with the solutions Sikafloor®–1590 / –2640 / –2650 and Sikafloor®–169 ESD. The product properties are adjusted to the relevant segments and combine fast curing, low odor and VOC emission, and improved color retention. 

Sika i-cure is an intelligent patented technology which can enhance the aesthetics and performance of polyurethane flooring. In 2-C polyurethanes the unwanted side reaction with moisture is suppressed and the final product cures independently to the moisture during application. The technology allows a quicker through cure and therefore a faster return to service. Use of the latent hardeners therefore allows robustness in application independent of climatic conditions which often affects traditional 2C polyurethanes resulting in aeration or bubbling in the film.

Products Sikafloor®-3240, Sikafloor®-324 and Sikafloor®-377 have been developed for a variety of applications including industrial flooring, logistics centres parking areas for high traffic.

A particular advantage of the Sikafloor®-377 is the quick cure and return to service for parking areas. It has also proven to give very good wear resistance when compared against traditional products.

Sika R&D has a strong history of developing 1-component waterbased coatings for a number of applications, including roof coatings (e.g. Sikalastic® -560), internal hygienic coatings (Sikagard® -400 range) and products for the treatment of external concrete facades (e.g. Sikagard® -550W). These products are based on a number of dispersion polymer technologies such as Acrylics, Styrene-Acrylics and Polyurethane Dispersions (PUD’s). Waterbased coatings generally offer key advantages in terms of environmental and sustainability topics due to their low odour, low VOC emissions and clean labelling.

The performance of bio-based products plays a decisive role in the demand for more sustainable coatings. Sika is further developing water-based protective coatings by using alternative, bio-based raw materials to reduce the product’s embodied carbon footprint. A new water-based platform for concrete protection coatings has been developed for use on reinforced concrete, Sikagard®-5500 SWE. The product contains a reduced amount of fossil-based raw materials and moves the formulation towards bio-based raw materials which are manufactured from renewable feedstock such as biogas or bio-naphtha. Ultimately this new development reduces the products embodied carbon footprint by approx. 30% compared to traditionally formulated water-based concrete protection coatings with corresponding performance.

Sika’s waterbased LAM products can be considered ‘non-reactive’ in a sense that the polymer is already formed but stabilised in a dispersion. Following application, the final coating film (or membrane) is formed via a two-stage process; Evaporation of water and co-solvents, followed by coalescence of the polymer binder particles. This is different to solvent based or 100% solids polyurethanes (or PUA’s) that are ‘reactive’ and undergo a chemical reaction during a curing process.

The challenge for formulators of water based products is to achieve the same performance as reactive systems. Sika’s latest waterbased roof coating, Sikalastic -580, offers a market leading USP of early rain resistance, which is a key market advantage for this type of technology. One drawback of traditional waterbased coatings is the potential to ‘wash-off’ if there is rainfall before the coating has fully dried. This is because the polymer is water soluble until hardened.  The rain resistance with Sikalastic® -580 is achieved by a novel technology that causes the coating to become resistant to wash-off in an earlier time-period than would naturally be achieved. Sikalastic® -580 is also designed to have a higher flexibility at low temperatures to make it more suitable in service for colder regions. The product pushes the boundaries and extends the application window classically achieved with waterbased acrylic coatings.