Free-flowing polymer composition

1. A free-flowing polymer composition in the form of free-flowing crumbs, the free-flowing crumbs consisting essentially of:

(i) 0.2 to 2.0 wt. % fumed silica with a tamped density of <75 g/L, a surface area (BET, measured by nitrogen gas adsorption) of at least 200 m 2 /g, and a pH of 3 to 5; and

(ii) 98.0 to 99.2 wt. % of a block copolymer selected from any of:

a) a tetra-branched block copolymer having a molecular weight of 100,000 to 800,000 represented by the general formula (A-B) 4 X;

b) a triblock copolymer having a linear or a radial triblock copolymer structure A-B-A or (A-B) n X, n=2 to 6, and a molecular weight of 75,000-600,000;

c) a linear diblock copolymer having a molecular weight of 25,000 to 250,000, represented by the general formula A-B; and

d) combinations thereof;

wherein:

A represents a polymer block of a mono alkenyl arene;

B represents a polymer block of a conjugated diene; and

X represents residues of a coupling agent;

wherein

the free-flowing crumbs are prepared by a method consisting essentially of:

removing solvent from a hydrogenation process for making the block copolymer, generating a slurry,

drying the slurry to generate crumbs, and

dusting the crumbs with the fumed silica to generate the free-flowing crumbs; and

wherein the free-flowing polymer composition requires less than 400 lbs/ft 2 to break in a blocking test.

2. The free-flowing polymer composition of claim 1 , wherein the fumed silica is hydrophilic.

3. The free-flowing polymer composition of claim 1 , wherein the block copolymer is a triblock copolymer having a coupled structure represented by the general formula (A-B) 2 X, and a molecular weight of 50,000 to 400,000.

4. The free-flowing polymer composition of claim 1 , wherein the block copolymer is a triblock copolymer, which comprises:

one block of a monovinylaromatic hydrocarbon and one block of a conjugated diene having a styrene equivalent peak molecular weight from 80,000 g/mole to 250,000 g/mole,

a vinyl content from 5 to 80 mol % based on the number of repeat monomer units in the conjugated diene block, and

a polystyrene content from 20 w % to 55 w %.

5. The free-flowing polymer composition of claim 1 , wherein the block copolymer is a triblock copolymer having a linear structure which comprises:

at least two blocks of monovinylaromatic hydrocarbon and at least one block of conjugated diene,

a styrene equivalent peak molecular weight that is 70,000 g/mole to 500,000 g/mole,

a vinyl content from 5 to 80 mole percent based on the number of repeat monomer units in the conjugated diene block,

a polystyrene content from 10% to 40%, and

the triblock copolymer has a melt index from <1 g/10 min. to 5 g/10 min. as determined by ASTM D-1238, condition G (200° C., 5 kg) (lower limit 0.1 g/10 m).

6. The free-flowing polymer composition of claim 1 , wherein the block copolymer is a triblock copolymer having a radial structure (A-B) n X, where n=2, and

wherein the triblock copolymer having the radial structure (A-B) 2 X has a styrene equivalent peak molecular weight of 1.5 to 2.5 times the styrene equivalent peak molecular weight of a diblock copolymer having a general formula A-B.

7. The free-flowing polymer composition of claim 1 , wherein the block copolymer is selectively hydrogenated.

8. The free-flowing polymer composition of claim 1 , wherein the composition is characterized as having a conical opening of less than 10 ft in a funnel flow test.

9. The free-flowing polymer composition of claim 1 , wherein the composition is characterized as having a conical opening of less than 3 ft. in a mass flow test.

10. The free-flowing polymer composition of claim 1 , wherein the composition is characterized as having a conical hopper angle of less than 15 degrees from vertical in a mass flow test.

11. The free-flowing polymer composition of claim 1 , wherein the composition requires less than 300 lbs/ft 2 to break in a blocking test.

12. The free-flowing polymer composition of claim 1 , wherein the fumed silica has a BET surface area in the range of 275-450 m 2 /g and a pH of 3.4 to 4.5 and tamped density of <75 g/L.

13. A melt formed or molded article comprising the free-flowing polymer composition of claim 1 .

14. The article of claim 13 , with <20% haze.

15. An oil gel comprising the free-flowing polymer composition of claim 1 .

16. An oil gel according to claim 15 , wherein the oil gel comprises 3-15 wt. % of the free-flowing composition based on 100 wt. % total composition of the oil gel, and wherein the oil gel has a shear stress at 77° F. of at least 3.

17. A method for making a free-flowing polymer composition in the form of free-flowing crumbs, the free-flowing crumbs consisting essentially of:

removing solvent from a hydrogenation process for making a block copolymer, generating a slurry,

drying the slurry to generate crumbs, and

blending the crumbs with:

0.05 to 2 wt. % of a fumed silica with a surface area (BET, measured by nitrogen gas adsorption) of at least 200 m 2 /g, and a pH of 3 to 5 and tamped density of <75 g/L;

wherein the block copolymer is selected from any of:

a) a tetra-branched block copolymer having a molecular weight of 100,000 to 800,000 represented by the general formula (A-B) 4 X;

b) a triblock copolymer having a linear or a radial triblock copolymer structure A-B-A or (AB) n X, and a molecular weight of 75,000 to 600,000;

c) a linear diblock copolymer having a molecular weight of 25,000 to 250,000 represented by the general formula A-B; and

d) combinations thereof;

wherein:

n=2 to 6;

A represents a polymer block of a mono alkenyl arene;

B represents a polymer block of a conjugated diene; and

X represents residues of a coupling agent;

wherein the block copolymer is present in an amount of 98.0 to 99.2 wt. % of the polymer composition; and

wherein the free-flowing polymer composition requires less than 400 lbs/ft 2 to break in a blocking test.

18. The method of claim 17 , wherein the fumed silica is hydrophilic.

19. The method of claim 17 , wherein the block copolymer is a triblock copolymer having a coupled structure represented by the general formula (A-B) 2 X, and a molecular weight of 50,000 to 400,000.

20. The method of claim 17 , wherein the fumed silica has a BET surface area in the range of 275-450 m 2 /g and a pH of 3.4 to 4.5 and tamped density of <75 g/L.