Non-sticky, soft and transparent styrenic thermoplastic elastomers

Patent metadata

Field	Value
Publication number	US-11891503-B2
Application number	US-201816494098-A
Country	US
Kind code	B2
Filing date	Mar 12, 2018
Priority date	Mar 16, 2017
Publication date	Feb 6, 2024
Grant date	Feb 6, 2024

Abstract

Thermoplastic elastomer compositions can be use for medical applications, Comprising: a) 97.1 to 90.9 wt.-% star-shaped block copolymer A with identical arms of the structure [S1-(S/B)k-(S/B)I-(S/B)m-S2]n-X, where S1 and S2 are vinylaromatic hard polymer and S/B are soft random vinylaromatic/diene copolymer blocks; X is a coupling center; and b) 2.9 to 9.1 wt.-% plasticizer B.

First claim

The invention claimed is:

1. A thermoplastic elastomer composition comprising components a), b), and c):
a) 97.1 to 90.9 wt.-% of at least one star-shaped block copolymer A of the structure
[S 1 -(S/B) k -(S/B) l -(S/B) m -S 2 ] n -X  (I),

where S 1 and S 2 are polymer blocks made from at least one vinylaromatic monomer and S/B are random copolymer blocks made from at least one vinylaromatic monomer and at least one diene forming a soft phase; X is a coupling center derived from a polyfunctional coupling agent;

b) 2.9 to 9.1 wt.-% of at least one plasticizer B; and
c) 0 to 2 wt.-% of further additives C;
wherein the sum of components a), b) and c) is 100 wt.-%;
the arms S 1 -(S/B) k -(S/B) l -(S/B) m -S 2 are identical;
the proportion of the blocks S 1 and S 2 (forming a hard phase), based on the entire block copolymer A, is from 24 to 40 wt.-%;
the vinylaromatic monomer/diene (=S/B) ratio of all of the blocks (S/B) is from 1/0.45 to 1/2.5;
the S/B-ratio of the blocks (S/B) k , (S/B) l and (S/B) m is different from each other;
the S/B-ratio of the blocks (S/B) k and (S/B) m is lower than the S/B-ratio of the block(s) (S/B) l ;
the weight ratio of blocks S2/S1 is from 0.1 to 0.8;
the weight average molar mass M w of the block copolymer A is from 200,000 to 350,000 g/mol;
n is a natural number from 3 to 8;
k and m are each 1; and
l is a natural number of at least 1.

2. The thermoplastic elastomer composition according to claim 1 comprising components a), b), and c) in the following amounts:
a) 96.2 to 91.7 wt.-%;
b) 3.8 to 8.3 wt.-%; and
c) 0 to 2 wt.-%.

3. The thermoplastic elastomer composition according to claim 1 , wherein the at least one plasticizer B is mineral oil.

4. The thermoplastic elastomer composition according to claim 1 which melt mass flow index (measured on a polymer melt at 200° C. and 5 kg load according to ISO 1133-1:2011) is in the range of from 8 to 16 cm 3 /10 min.

5. The thermoplastic elastomer composition according to claim 1 , wherein n is a natural number from 3 to 5.

6. The thermoplastic elastomer composition according to claim 1 , wherein X is a coupling center derived from epoxidized linseed oil or epoxidized soybean oil.

7. Thermoplastic elastomer composition according to claim 1 , wherein M w of the block copolymer A is from 210,000 to 320,000 g/mol.

8. The thermoplastic elastomer composition according to claim 1 , wherein Mw of the polymer block S 1 is in the range of from 18,000 to 36,000 g/mol; and Mw of the polymer block S 2 is in the range of from 4000 to 8100 g/mol.

9. The thermoplastic elastomer composition according to claim 1 , wherein the weight ratio of blocks S 2 /S 1 of block copolymer A is from 0.1 to 0.6.

10. The thermoplastic elastomer composition according to claim 1 , wherein the S/B-ratio of the copolymer block (S/B) k is from 0.5 to 1.0; the S/B-ratio of the copolymer block(s) (S/B) l is from 0.5 to 1.2; and the S/B-ratio of the copolymer block (S/B) m is from 0.3 to 0.8.

11. The thermoplastic elastomer composition according to claim 1 , wherein the weight average molar mass M w of the copolymer blocks (S/B) k , (S/B) l and (S/B) m is different from each other; Mw (S/B) k is in the range of from 13,800 to 26,900 g/mol; Mw (S/B) l is in the range of from 21,200 to 41,000 g/mol; and Mw (S/B) m is in the range of from 11,500 to 23,000 g/mol.

12. A process for the preparation of a thermoplastic elastomer composition according to claim 1 , wherein component a) is introduced continuously into an extruder and then component b) and optionally further components c) are metered in.

13. A process for the preparation of a thermoplastic elastomer composition according to claim 1 , wherein component b) and optional component c)—as such or in solution—are added into a solution of block copolymer A, then to homogenize the liquids, and subsequently to free the product from the solvent.

14. A shaped article produced from the thermoplastic elastomer composition according to claim 1 .

15. A method of using a thermoplastic elastomer composition according to claim 1 for medical applications.

16. A star-shaped block copolymer A according to claim 1 .

17. A process for the preparation of block copolymer A of formula (I) according to claim 1 characterized by
i) a single initiation,
ii) first addition and polymerization of vinyl aromatic monomer,
iii) at least 3 times addition and polymerization of a vinyl aromatic monomer and diene mixture,
iv) second addition and polymerization of vinyl aromatic monomer, and
v) a coupling step after the addition and polymerization of the vinylaromatic monomers of the last polymer block.

Assignees

• Ineos Styrolution Group Gmbh

Inventors

• Verswyvel Michiel
• Niessner Norbert
• Jahnke Eike
• Wagner Daniel
• Knoll Konrad

Classifications

• C08L53/02 Primary

  of vinyl-aromatic monomers and conjugated dienes · CPC title

• A61M39/00

  Tubes, tube connectors, tube couplings, valves, access sites or the like, specially adapted for medical use (for respiratory devices, e.g. tracheal tubes A61M16/00; artificial heart valves A61F2/24) · CPC title

• C08F297/044 Primary

  using a coupling agent · CPC title

• C08L91/00

  Compositions of oils, fats or waxes; Compositions of derivatives thereof · CPC title

• C08L2203/02

  for biomedical use · CPC title