Waterproofing membranes with a specific gravity of under 1 G/CM
Disclosed are waterproofing membranes consisting of a backing impregnated with a bituminous formulation comprising industrial bitumen, a mineral filler, a thermoplastic polymer or a mixture of thermoplastic polymers, characterized in that the mineral filler consists of hollow glass microspheres with a density of between 0.10 and 0.14 g/cm 3 and a size of less than 120 μm.
1. Waterproofing membranes consisting of a reinforcing material impregnated with a bituminous formulation comprising industrial bitumen, a mineral filler, a thermoplastic polymer or a mixture of thermoplastic polymers, wherein the mineral filler consists of hollow glass microspheres with a density of between 0.10 and 0.14 g/cm 3 and a size of less than 120 μm.
2. Waterproofing membranes as claimed in claim 1 , wherein the thermoplastic polymer is selected from low-density polyethylene, high-density polyethylene, isotactic polypropylene, ethylene/propylene copolymer, ethylene/propylene/butene terpolymer, atactic polypropylene, and
styrene-butadiene-styrene block copolymer.
3. Waterproofing membranes as claimed in claim 1 , wherein the industrial bitumen is present in quantities of between 70% and 80% by weight.
4. Waterproofing membranes as claimed in claim 1 , wherein the thermoplastic polymer or polymers are present in quantities of between 15% and 25%.
5. Waterproofing membranes as claimed in claim 1 , wherein the mineral filler is present in quantities of between 2% and 7% by weight.
6. Waterproofing membranes of claim 5 , wherein the mineral filler is present in quantities of between 3% and 5% by weight.
7. Waterproofing membranes as claimed in claim 1 , characterized by a specific gravity of under 1 g/cm 3 .
8. Process for the preparation of waterproofing membranes belonging to different classes defined by cold bending values, measured according to standard EN 1109, in the 0-25° C. range, said method comprising: impregnating a reinforcing material with a bituminous formulation comprising industrial bitumen, a mineral filler consisting of hollow glass microspheres with a density of between 0.10 and 0.14 g/cm 3 and a size of less than 120 μm, and a thermoplastic polymer or a mixture of thermoplastic polymers.
9. Process as claimed in claim 8 , wherein the reinforcing material is a non-woven polyester.
10. Waterproofing membranes obtained by the process claimed in claim 8 .
11. A bituminous formulation for the preparation of waterproofing membranes which comprises industrial bitumen, a mineral filler consisting of hollow glass microspheres with a density of between 0.10 and 0.14 g/cm 3 and a size of less than 120 μm, and a thermoplastic polymer or a mixture of thermoplastic polymers.