Prefabricated membrane based on modified polyurethane bituminous binder and process for production

A process for production of a sealing membrane having stability to UV exposure and formed of a support or reinforcement, the support or reinforcement being coated on at least one surface and impregnated throughout, with a bitumen base composition, the bitumen base composition being a thermoplastic bituminous coating and or impregnation composition that has a following weight proportion based on a total weight of the composition:

• 60 to 80% bitumen,
• 15 to 40% thermoplastic polyurethane,
• 0 to 5% aromatic oil,
• 0 to 40% filler, and
• 0 to 0.5% catalyst,
• wherein the bituminous coating and or impregnation composition is softenable by reheating and recover its properties after subsequent cooling,
• wherein the sealing membrane is applied by heating by torch welding or hot air,
• wherein the sealing membrane is stable to UV exposure,
• wherein the thermoplastic polyurethane is obtained from a diisocyanate of a functionality substantially equal to 2, a polyol of functionality substantially equal to 2, and a chain elongation agent,
• wherein the polyurethane molecules are free of double carbon-carbon bonds, and
• wherein the polyols are free of ethylene linkages,
• said process comprising:
• bringing the bitumen to a temperature higher than a melting temperature of said bitumen,
• adding the polyol or the polyols and the isocyanate forming the thermoplastic polyurethane,
• agitating to obtain about a theoretical quantity of NCO,
• adding the chain elongating agent, the catalyst and other components if present, progressively increasing the temperature to about 180° C.,
• agitating intermittently or continuously, until polymerization, and
• applying the hot bitumen base composition in a layer on a support by one or more operations of coating or impregnation.

A process for the production of a prefabricated sealing membrane having stability to UV exposure, comprising:

• a support in the form of a fibrous backing;
• and
• a bitumen base composition applied to a surface of the support or impregnated throughout the support,
• the bitumen base composition comprising based on a total weight of the composition:
• 60 to 80% bitumen,
• 15 to 40% thermoplastic polyurethane,
• 0 to 5% aromatic oil,
• 0 to 40% filler, and
• 0 to 0.5% catalyst,
• the bitumen base composition being thermoplastic, softening under action of heat and recovering its properties after subsequent cooling, and
• the prefabricated sealing membrane being applied by torch welding or hot air and stable to UV exposure, wherein,
• the thermoplastic polyurethane comprises a diisocyanate, a polyol, and a chain lengthening agent,
• the thermoplastic polyurethane molecules are free of double carbon-carbon bonds,
• the polyols are free of ethylene linkages,
• a functionality of the polyols is between 1.95 and 2.05, and
• a functionality of the isocyanates is between 2.0 and 2.1,
• said process comprising:
• synthesizing a prepolymer of the thermoplastic polyurethane,
• introducing said prepolymer into the bitumen heated to a temperature higher than the melting temperature of the bitumen,
• adding at least the chain elongating agent, then the catalyst and finally the other components if present,
• heating and agitating to achieve polymerization, and
• applying the hot bitumen base composition in a layer on the support by one or more operations of coating or impregnation.

A process for the production of a prefabricated sealing membrane having stability to UV exposure, comprising:

• a support comprising a fibrous backing;
• and
• a bitumen base composition applied to a surface of the support or impregnated throughout the support,
• the bitumen base composition comprising based on a total weight of the composition:
• 60 to 80% bitumen,
• 15 to 40% thermoplastic polyurethane,
• 0 to 5% aromatic oil,
• 0 to 40% filler, and
• 0 to 0.5% catalyst,
• the bitumen base composition being thermoplastic, softening under action of heat and recovering its properties after subsequent cooling, and
• the prefabricated sealing membrane being applied by torch welding or hot air and highly stable to UV exposure, wherein,
• the thermoplastic polyurethane comprises a diisocyanate, a polyol, and a chain lengthening agent,
• the thermoplastic polyurethane molecules are free of double carbon-carbon bonds,
• the polyols are free of ethylene linkages,
• a functionality of the polyols is between 1.95 and 2.05, and
• a functionality of the isocyanates is between 2.0 and 2.1,
• said process comprising:
• bringing the bitumen to a temperature higher than a melting temperature of the bitumen,
• adding the polyol or the polyols and the isocyanate to form the thermoplastic polyurethane,
• agitating to obtain about a theoretical quantity of NCO,
• adding the chain elongating agent, the catalyst and other components if present,
• progressively increasing the temperature,
• agitating intermittently or continuously, until polymerization, and
• applying the hot bitumen base composition in a layer on a support by one or more operations of coating or impregnation.

A process for the production of a prefabricated sealing membrane having stability to UV exposure, comprising:

• a support;
• and
• a bitumen base composition applied to the support,
• the bitumen base composition comprising based on a total weight of the composition:
• 60 to 80% bitumen,
• 15 to 40% thermoplastic polyurethane, comprising a diisocyanate, a polyol, and a chain lengthening agent,
• 0 to 5% aromatic oil,
• 0 to 40% filler, and
• 0 to 0.5% catalyst,
• the bitumen base composition being thermoplastic, softening under action of heat and recovering its properties after subsequent cooling so that the prefabricated sealing membrane is suitable for application by torch welding or hot air, and
• the prefabricated sealing membrane being stable to UV exposure,
• the thermoplastic polyurethane molecules are free of double carbon-carbon bonds,
• the polyols are free of ethylene linkages, and
• a functionality of the polyols is between 1.95 and 2.05,
• said process comprising:
• synthesizing a prepolymer of the thermoplastic polyurethane,
• introducing said prepolymer into the bitumen heated to a temperature higher than the melting temperature of the bitumen,
• adding at least the chain elongating agent, then the catalyst and finally the other components if present,
• heating and agitating to achieve polymerization, and
• applying the hot bitumen base composition in a layer on the support, by one or more operations of coating or impregnation.

A process for the production of a sealing membrane having stability to UV exposure, comprising:

• a support;
• and
• a bitumen base composition applied to the support,
• the bitumen base composition comprising based on a total weight of the composition:
• 60 to 80% bitumen,
• 15 to 40% thermoplastic polyurethane, comprising a diisocyanate, a polyol, and a chain lengthening agent,
• 0 to 5% aromatic oil,
• 0 to 40% filler, and
• 0 to 0.5% catalyst,
• the bitumen base composition being thermoplastic, softening under action of heat and recovering its properties after subsequent cooling so that the sealing membrane is suitable for application by torch welding or hot air, and
• the sealing membrane being stable to UV exposure, wherein,
• the thermoplastic polyurethane molecules are free of double carbon-carbon bonds,
• the polyols are free of ethylene linkages, and
• a functionality of the polyols is between 1.95 and 2.05,
• wherein said process comprises:
• bringing the bitumen to a melting temperature of bitumen,
• adding the polyol or the polyols and the isocyanate forming the thermoplastic polyurethane,
• agitating to obtain about a theoretical quantity of NCO,
• adding the chain elongating agent, the catalyst and other components if present,
• progressively increasing the temperature to about 180° C.,
• agitating intermittently or continuously, until polymerization, and
• applying the hot bitumen base composition in a layer on a support by one or more operations of coating or impregnation.