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Parking garage floors - highly resistant and solvent-free
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Bayer MaterialScience AG
: 19 April, 2004 (Company News) |
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Bayer MaterialScience AG has introduced a new reactive polyurethane into the market that can be used as a permanent plasticizer for epoxy amine resins. The new product, Desmocap |
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Furthermore, it contains no heavy metals. “Due to the low viscosity of the reactive polyurethane, the epoxy systems are now suitable for use with other coating techniques, thus opening up new applications,” says Dr. Michael Mager, a coatings expert at Bayer MaterialScience, in a presentation at the 27th FATIPEC Congress in Aix-en-Provence from April 19 – 21, 2004. One application of epoxy resins modified in this manner is the formulation of highly resistant floor coatings for parking garages.
Epoxy resin-based casting resins are well proven thanks to their outstanding mechanical strength, chemical resistance, thermal stability and excellent adhesion on numerous substrates. These systems are generally formulated without solvents for industrial flooring applications. Instead, low molar mass epoxy amine resins are used to achieve the lowest possible application viscosity. Plasticizers are added to these casting resins because of their brittleness. Modification using reactive polyurethanes has proven effective for more than 30 years. These crosslink with the amine via urea bridges and can thus be considered as internal plasticizers. Other plasticizers that do not react with the epoxy amine network exhibit a lesser plasticizing effect from the very beginning, which further diminishes over time due to the migration of the additive.
The new reactive polyurethane has a viscosity of only about 65 Pa·s at 23 °C, a significantly lower value than the roughly 100 Pa·s of the product it replaces. When reacted in a 1:1 ratio by weight with a typical epoxy amine resin, the system achieves a Shore D hardness of approx. 58. During testing, tensile stress at break was roughly 21 MPa; elongation at break approx. 49 percent and tear resistance was roughly 34 N/mm. The best results with respect to toughness and wear resistance were obtained with polyurethane:epoxy weight ratios of between 40:60 and 70:30. |
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