Polymer composition comprising at least one vinyl aromatic diene block copolymer and specific amounts of oil

1. A polymer composition consisting of:

94.9 to 97.49% by weight, based on the total polymer composition:

at least one block copolymer P, having one of the following formulas (I) to (III):

(A-B/A) n -A  (I),

X—[(B/A-A) n ] m+1   (II),

Y—[(B/A-A) n ] m+1   (III),

wherein the abbreviations and indices have the following meaning:

A is a vinyl aromatic block forming a hard phase, which is composed of at least one vinyl aromatic monomer M A ,

B/A is a diene block forming a soft phase, which is composed of at least one conjugated diene monomer M B and at least one vinyl aromatic monomer M A ,

X is the radical of an m+1-functional initiator,

Y is the radical of an m+1-functional coupling agent,

n is a natural number from 1 to 10, and

m is a natural number from 1 to 10;

2.5 to 5% by weight, based on the total polymer composition,

at least one oil component C, wherein the oil component is one or more paraffin oil; and

0.01 to 1% by weight, based on the total polymer composition, one or more further components E;

wherein:

the at least one block copolymer P comprises 40 to 75% by weight, based on the block copolymer P, of the at least one vinyl aromatic monomer M A and 25 to 60% by weight, based on the block copolymer P, of the at least one conjugated diene monomer M B ;

the glass transition temperature's T g of the vinyl aromatic block's A is/are above 25° C. and the glass transition temperature's T g of the diene block's B/A is/are below 25° C.,

the proportion of the vinyl aromatic block's forming the hard phase is from 5 to 40% by volume, based on the total volume of block copolymer P;

the relative amount of 1,2 linkages in the diene block B/A, based on the sum of 1,2- and 1,4-cis/trans-linkages, is less than or equal to 15%; and

the weight average molecular weight M w of the block copolymer P is in the range of 120,000 to 300,000 g/mol.

2. The polymer composition according to claim 1 , wherein the vinyl aromatic monomer M A is at least one monomer selected from the group consisting of styrene, α-methylstyrene, vinyltoluene, and 1,1-diphenylethylene, and the conjugated diene monomer M B is at least one monomer selected from the group consisting of butadiene and isoprene.

3. The polymer composition according to claim 1 , wherein the vinyl aromatic monomer M A is at least one monomer selected from the group consisting of styrene and α-methylstyrene, and the conjugated diene monomer M B is butadiene.

4. The polymer composition according to claim 1 , wherein the molecular weight of the vinyl aromatic block's A is/are in the range of 5,000 to 100,000 g/mol; and the molecular weight of the diene block's B/A is/are in the range of 20,000 to 250,000 g/mol.

5. The polymer composition according to claim 1 , wherein the glass transition temperature T g of the vinyl aromatic block's A is/are above 50° C.; and the glass transition temperature T g of the diene block's B/A is/are below 5° C.

6. The polymer composition according to claim 1 , wherein the relative amount of 1,2 linkages in the diene block B/A of the block copolymer P, based on the sum of 1,2- and 1,4-cis/trans-linkages, is less than or equal to 12%.

7. The polymer composition according to claim 1 , wherein the oil component C is at least one paraffin oil having a viscosity in the range of 20 to 300 m Pas, measured at a temperature in the range of 20 to 25° C.

8. The polymer composition according to claim 1 , wherein the block copolymer P is obtained by a process which comprises the step of forming the block copolymer by sequential anionic polymerization, where at least the polymerization step of the at least one block B/A takes place in the presence of a potassium salt as randomizer.

9. A moulded part made from the polymer composition according to claim 1 .

10. The moulded part according to claim 9 , wherein the moulded part is selected from extruded sheets, extruded multilayer sheets, extruded tubings, multilumen tubings, drip chamber parts, food packagings, beakers, plates, and labels.

11. A process for the production of the polymer composition according to claim 1 , wherein the at least one block copolymer P is mixed with the at least one oil component C, and optionally further components E.

12. The process according to claim 11 , wherein the components are mixed by melt extrusion.