IP Library › Granted Patent US 7,517,932
Granted Patent B2
US 7,517,932 · App. 11/398,249 · Granted Apr 14, 2009

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

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Quick Facts
Patent No.
US 7,517,932
App. No.
11/398,249
Filed
Apr 5, 2006
Granted
Apr 14, 2009
Kind
B2
Examiner
LEE, RIP A
Art Unit
1796
USPC
524/571
Abstract

The present invention provides a poly(styrene-butadiene-styrene) polymer having a high vinyl content in the butadiene block. The polymer also has a polystyrene content from 15% to 20% by weight; a coupling efficiency from 50 to 80%; a styrene block molecular weight from 9,000 to 10,000 g/mol; a vinyl content from 20 to 45%; and a melt flow rate of equal to or greater than 10.

Claims (29)

1. 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 of from 15% to 20% by weight;

ii) a coupling efficiency of from 50% to 80%;

iii) a styrene block molecular weight of each styrene block of from 9,000 to 9,600 g/mol;

iv) a vinyl content in the butadiene block of from 20 to 40%; and

v) a melt flow rate of equal to or greater than 10 g/10 min (200° C., 5 kg),

b) a tackifying resin;

c) a plasticizer in the amount of 5 to 75 parts by weight; and

d) an anti-oxidant.

2. The hot melt adhesive composition of claim 1 wherein the polymer has:

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

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

iii) a styrene block molecular weight of each styrene block of from 9,400 to 9,600 g/mol; and

iv) a vinyl content in the butadiene block of from 25% to 40%.

3. The hot melt adhesive composition of claim 1 wherein the polymer has:

i) a polystyrene content of about 19%;

ii) a coupling efficiency of about 70%;

iii) a styrene block molecular weight of each styrene block of about 9,500 g/mol; and

iv) a vinyl content in the butadiene block of about 30%.

4. The hot melt adhesive composition of claim 1 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; and

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

5. The hot melt adhesive composition of claim 1 wherein the tackifier is present in an amount of from 50 to 200 parts by weight.

6. The hot melt adhesive composition of claim 1 wherein the plasticizer is present in an amount of from 10 to 40 parts by weight.

7. The hot melt adhesive composition of claim 5 wherein the tackifier is present in an amount of from 100 to 150 parts by weight.

8. The hot melt adhesive composition of claim 1 wherein the styrene block molecular weight is 9,100 g/mol.