Poly (styrene-butadiene-styrene)polymers having a high vinyl content in the butadiene block and hot melt adhesive compositions comprising said polymers

1 - 10 . (canceled)

11 . A poly(styrene-butadiene-styrene) polymer having a high vinyl content in the butadiene block comprising in combination:

i) a polystyrene content from 15% to 20% by weight;

ii) a coupling efficiency from 50 to 80%;

iii) a step I molecular weight from 9,000 to 10,000 kg/mol;

iv) a vinyl content from 20 to 45%; and

v) a melt flow rate of equal to or greater than 10.

12 . The polymer of claim 11 wherein the polystyrene content is from 16 to 19% by weight.

13 . The polymer of claim 11 wherein the polystyrene content is from 16 to 18% by weight.

14 . The polymer of claim 11 wherein the coupling efficiency is from 60 to 75%.

15 . The polymer of claim 11 wherein the coupling efficiency is from 65 to 70%.

16 . The polymer of claim 11 wherein the vinyl content is from 25 to 40%.

17 . The polymer of claim 11 wherein the vinyl content is from 30 to 35%.

18 . The polymer of claim 12 wherein the vinyl content is from 25% to 40%.

19 . The polymer of claim 18 wherein the coupling efficiency is from 60% to 75%.

20 . The polymer of claim 17 wherein the polystyrene content is from 16% to 18% by weight.

21 . A hot melt adhesive composition comprising:

a) a poly(styrene-butadiene-styrene) polymer having a high vinyl content in the butadiene block, said polymer having:

i) a polystyrene content from 15% to 20% by weight;

ii) a coupling efficiency from 50 to 80%;

iii) a step I molecular weight from 9,000 to 10,000 kg/mol;

iv) a vinyl content from 20 to 45%; and

v) a melt flow rate of equal to or greater than 10.

b) a tackifying resin;

c) an optional plasticizer; and

d) an anti-oxidant.

22 . The hot melt adhesive composition of claim 21 wherein the polymer has the following characteristics:

i) a polystyrene content from 16% to 19%;

ii) a coupling efficiency from 60% to 75%;

iii) a step I MW from 9,400 to 9,600 kg/mol; and

iv) a vinyl content from 25% to 40%.

23 . The hot melt adhesive composition of claim 21 wherein the polymer has the following characteristics:

i) a polystyrene content of about 19%;

ii) a coupling efficiency of about 70%;

iii) a step I MW of about 9,500 kg/mol; and

iv) a vinyl content of about 30%.

24 . The hot melt adhesive composition of claim 21 having

a) a hot melt viscosity at 170° C. during 24 hours lower than 100 Pa.S (ASTM D3236-78);

b) a rolling back tack of 1 cm to 5 cm (ASTM D3121-73);

c) a flap test, 500 g weight, higher than 120 minutes (method described herein); and

d) a HP 40° C., 1 kg weight, higher than 50 minutes (ASTM D3654-82).

25 . The hot melt adhesive composition of claim 21 wherein the tackifier is present in an amount from 50 to 200 parts by weight.

26 . The hot melt adhesive composition of claim 21 wherein the plasticizer is present in an amount is up to 100 parts by weight.

27 . The hot melt adhesive composition of claim 22 wherein the tackifier is present in an amount from 100 to 150 parts by weight.

28 . The hot melt adhesive composition of claim 22 wherein the plasticizer is present in an amount is up to 5 to 75 parts by weight.