Modified bitumen is a material with properties changed by injection (addition) of special substances (modifiers). It is used in road and civil construction. In the latter case, modified bitumen is an element of roofing.
Atactic polypropylene (APP) and artificial rubber Styrene Butadiene Styrene (SBS) are used most often for bitumen modification.
APP is used to satisfy the following conditions:
- availability of modern equipment compatible with bitumen;
- strictly following the technology process;
- high quality mixing of components.
Polypropylene, according to its chemical nature, is thermoplastic. Due to APP properties, the resulting modified bitumen confers durability to high temperature and ultraviolet rays, as well as cyclic stress, to the roofing materials.
Materials based on APP-modifiers received good feedback from roofing contractors. Possible repair difficulties are solved due to good adhesion and high stability to thermal expansion and contraction.
SBS modifiers are required to confer cold temperature flexibility to bitumen. Compared with APP, SBS has much lower heat endurance. Bitumen modified with artificial rubber has good adhesion, ensuring high durability and reliability of roofing coat.
As for flexibility, if SBS-modifier is applied, it can achieve 1500-2000%. This means that cyclic stress durability is quite high.
The process of making quality polymer modified bitumen is difficult. However, the UVB-2 plants produced by GlobeCore make it much easier, since they allow working with various forms of modifiers: powders, granules, etc.