Water-based polyurethane floor paint
Based on the development trend of the construction industry in recent years, higher requirements have been put forward for the performance, construction efficiency and environmental friendliness of flooring paints. The new two-component waterborne polyurethane technology fully meets the market development needs. The floor coatings developed based on these technologies are widely used in commercial and industrial flooring and have excellent wear resistance, scratch resistance and chemical resistance.
Overview
Epoxy paint is currently the dominant technology in floor coatings. As the market demand for floor coating performance increases, polyurethane floor coatings based on new technologies are also being used in the field of high performance floor coatings. Two-component polyurethane floor coatings have become the benchmark technology for high performance floor coatings due to their excellent weather resistance, chemical resistance, rigidity and flexibility, abrasion resistance and scratch resistance. However, although the performance of traditional solvent-based polyurethane coatings is excellent, their large odor, high VOC content, and flammability and explosive properties limit the use of this technology, especially for indoor applications. At the same time, the increasing environmental requirements have provided the impetus for innovation in waterborne technology, so the innovative two-component waterborne polyurethane technology fits the market trend of high performance, environmental protection and high efficiency.
Cement-based self-leveling has developed rapidly in recent years, and overlay protection is essential to ensure that contaminants do not penetrate the cement self-leveling and leave a permanent stain. The original solution was to apply a single component sealer followed by a wax treatment on top. The advantage of this solution is that after surface contamination, the contaminants can be removed by waxing water and then re-waxed and refurbished. The disadvantage is that it requires frequent maintenance, while in the case of long-term immersion with open water, water will penetrate into the self-leveling, leading to pollution occurring and difficult to eliminate. The new two-component waterborne polyurethane floor paint is ideal for cement-based self-leveling overlays. It not only provides long-lasting, high-quality protection, but also maintains the original cement-based self-leveling color.
This article introduces the basic principle and performance of two-component waterborne polyurethane, and introduces some application cases in cement-based self-leveling to share with you.
Mixing and film formation of two-component waterborne polyurethane
Unlike the homogeneous system of solvent-based polyurethane coatings, the mixing process of two-component waterborne polyurethane will form a three-phase system between the polyisocyanate component and the polyol component, i.e., water (continuous phase), hydroxy resin dispersed phase (including a part of polyisocyanate that has entered the hydroxy resin dispersed phase under shear) and polyisocyanate dispersed phase. As mentioned earlier, a very small portion of NCO on the surface of the droplet of the polyisocyanate dispersed phase will react with water to produce a polyurea film, which plays a protective role, so that the NCO inside the droplet will not react with water at this stage, thus ensuring that the coating has sufficient operability time.
The film formed by the chemical cross-linking reaction has properties comparable to those of conventional solvent-based polyurethane coatings: excellent chemical resistance, scratch resistance, abrasion resistance and weather resistance, while its VOC content is greatly reduced.
Properties of two-component waterborne polyurethane floor coatings
Aliphatic system → weathering and UV resistance
Low viscosity hydrophilic modified polyisocyanate → easy to mix by hand
Moderately hydrophilic coating film → excellent resistance to stickiness and dirt, easy to clean
Cross-linking → easy cleaning, chemical resistance and abrasion resistance
Medium crosslinking density → balanced film respiration
High crosslinking density → Resistant to hot tire marks
Co-solvent-free aqueous system → low VOC, low odor
Polyurethane structure → flexibility (even at low temperatures)
Rigid and flexible → excellent scratch resistance
Comparison of two-component waterborne polyurethane and waterborne epoxy
Compared with it, two-component waterborne polyurethane has better weather resistance, acid resistance and scratch resistance and is especially suitable for use as a topcoat, while waterborne epoxy is more suitable for use in less demanding applications and can also be used as a primer in combination with waterborne polyurethane.
Based on the above analysis, it can be seen that two-component water-based polyurethane floor paint has great advantages compared with traditional floor paint, but since the cost of polyurethane is much higher than traditional floor paint, this greatly limits its large area promotion, mainly in some high-end applications, such as commercial underground parking lots. Cultural centers, exhibition halls, etc. How can we reduce the cost of polyurethane floor paint while keeping the same performance is what we are going to introduce in the future articles.
