Bituminous composition
View Patent ↗A bituminous composition which comprises a bituminous component and a block copolymer which comprises at least two blocks of a conjugated diene and at least two blocks of a monovinylaromatic hydrocarbon, being of the general formula: S 1 —B 1 —S 2 —B 2 wherein B 1 is a block of polymerized conjugated diene comprising at least 50 mole % isoprene having an apparent molecular weight of from 180,000 to 400,000, S 1 and S 2 are blocks of polymerized monovinylaromatic hydrocarbon having a weight average molecular weight of 12,000 to 40,000, and B 2 is a block of polymerized conjugated diene comprising at least 50 mole % isoprene having an apparent molecular weight of from 15,000 to 60,000; wherein the weight ratio W of B 1 over B 2 is in the range of 3.0 to 12.0; and wherein the content of polymerized monovinylaromatic hydrocarbon is in the range from 10 to 35 wt. %.
1. A bituminous composition for use in a self adhesive shingle or roofing felt, said composition comprising a bituminous component and a block copolymer, said block copolymer comprising at least two blocks of a conjugated diene and at least two blocks of a monovinylaromatic hydrocarbon of the general formula:
S 1 —B 1 —S 2 —B 2
wherein B 1 is a block of polymerized conjugated diene comprising at least 80 mole % isoprene having an apparent molecular weight of from 180,000 to 400,000, S 1 and S 2 are blocks of polymerized monovinylaromatic hydrocarbon comprising at least 99 mole % styrene and having a weight average molecular weight of 12,000 to 40,000, and B 2 is a block of polymerized conjugated diene comprising at least 80 mole % isoprene having an apparent molecular weight of from 15,000 to 60,000; wherein the weight ratio W of B 1 over B 2 is in the range of 3.0 to 12.0; and wherein the content of polymerized monovinylaromatic hydrocarbon is in the range from 10 to 35% wt.
2. The bituminous composition of claim 1 , wherein polymer blocks B 1 and B 2 each independently comprise at least 99 mole % isoprene.
3. The bituminous composition of claim 1 , wherein polymer block B 1 has an apparent molecular weight of from 250,000 to 350,000.
4. The bituminous composition of claim 1 , wherein polymer blocks S 1 and S 2 each independently have a molecular weight of from 20,000 to 35,000.
5. The bituminous composition of claim 1 , wherein the weight ratio W is in the range of from about 4.0 to about 8.0.
6. The bituminous composition of claim 1 , wherein the weight ratio W is about 6.0.
7. The bituminous composition of claim 1 , which comprises on the total weight of the bituminous composition from 70 to 95 W % of the bituminous component and from 30 to 5 W % of the block copolymer.
8. The bituminous composition of claim 1 , wherein the bituminous component has a penetration of less than 300 dmm (decamilimeters) at 25° C.
9. A block copolymer which comprises at least two blocks of a conjugated diene and at least two blocks of a monovinylaromatic hydrocarbon, being of the general formula:
S 1 —B 1 —S 2 —B 2
wherein B 1 is a block of polymerized conjugated diene comprising at least 80 mole % isoprene having an apparent molecular weight of from 180,000 to 400,000, S 1 and S 2 are blocks of polymerized monovinylaroniatic hydrocarbon comprising at least 99 mole % styrene and having a weight average molecular weight of 12,000 to 40,000, and B 2 is a block of polymerized conjugated diene comprising at least 80 mole % isoprene having an apparent molecular weight of from 15,000 to 60,000; wherein the weight ratio W of B 1 over B 2 is in the range of 3.0 to 12.0; and wherein the content of polymerized monovinylaromatic hydrocarbon is in the range from 10 to 35% wt.
10. A coating comprising a bituminous composition that comprises a bituminous component and a block copolymer, said block copolymer comprising at least two blocks of a conjugated diene and at least two blocks of a monovinylaromatic hydrocarbon of the general formula:
S 1 —B 1 —S 2 —B 2
wherein B 1 is a block of polymerized conjugated diene comprising at least 80 mole % isoprene having an apparent molecular weight of from 180,000 to 400,000, S 1 and S 2 are blocks of polymerized monovinylaromatic hydrocarbon comprising at least 80 mole % styrene and having a weight average molecular weight of 12,000 to 40,000, and B 2 is a block of polymerized conjugated diene comprising at least 80 mole % isoprene having an apparent molecular weight of from 15,000 to 60,000; wherein the weight ratio W of B 1 over B 2 is in the range of 3.0 to 12.0; and wherein the content of polymerized monovinylaromatic hydrocarbon is in the range from 10 to 35% wt.
11. The bituminous composition of claim 7 , wherein polymer blocks B 1 and B 2 each independently comprise at least 99 mole % isoprene and the weight ratio W is in the range of from about 4.0 to about 8.0, polymer block B 1 has an apparent molecular weight of from 250,000 to 350,000, polymer blocks S 1 and S 2 each independently have a molecular weight of from 20,000 to 35,000.