Process for the production of a thermoplastic elastomer and the thermoplastic elastomer
A thermoplastic elastomer contains (a) hard segments of a polyester and (b) soft segments containing repeating units derived from an aliphatic carbonate, wherein the thermoplastic elastomer exhibits a melt flow index (MFI) measured at 230° C. under a load of 10 kg (MFI 230° C./10 kg) according to ISO1133 (2011) of at most 40 g/10 min. The thermoplastic elastomer is produced by subjecting a precursor of the thermoplastic elastomer to solid state post reaction processing at a temperature between 140 and 170° C. until the thermoplastic elastomer has the required MFI of at most 40 g/10 min measured at 230° C. under a load of 10 kg (MFI 230° C./10 kg) according to ISO1133 (2011).
1. A process for the production of a thermoplastic elastomer containing (a) hard segments of a polyester and (b) soft segments comprising repeating units derived from an aliphatic carbonate, wherein the process comprises subjecting a precursor thermoplastic elastomer to solid state post-reaction processing at a temperature between 140 and 170° C. until the thermoplastic elastomer has a melt flow index (MFI) measured at 230° C. under a load of 10 kg (MFI 230° C./10 kg), according to ISO1133 (2011) of at most 40 g/10 min.
2. The process according to claim 1 , wherein the precursor thermoplastic elastomer is subjected to solid state post-reaction at a temperature below 165° C.
3. The process according to claim 1 , wherein the hard segments (a) of a polyester contain as repeating units butylene terephthalate.
4. The process according to claim 1 , wherein soft segments (b) contain alkylene carbonate repeating unit is represented by Formula I:
where R=H and/or alkyl; and
X=2-20.
5. The process according to claim 1 , wherein the hard segments (a) and the soft segments (b) are bonded via ester bonds forming copolyester units and the copolyester units are joined by a urethane group having the formula:
where R1=an alkyl, aryl or aralkyl group and p=2 or 3.
6. A thermoplastic elastomer comprising:
(a) hard segments of a polyester, and
(b) soft segments which comprise repeating units derived from an aliphatic carbonate, wherein
the thermoplastic elastomer has a melt flow index (MFI) measured at 230° C. under a load of 10 kg (MFI 230° C./10 kg) according to ISO1133 (2011) of at most 40 g/10 min.
7. The thermoplastic elastomer according to claim 6 , wherein the MFI of the thermoplastic elastomer is at most 30.
8. The thermoplastic elastomer according to claim 6 , wherein the thermoplastic elastomer has a melting temperature measured with DSC according to ISO 11357-1:1997 under air atmosphere (purge 50 ml/min) using a heating and cooling rate of 20 K/min is at least 180° C.
9. The thermoplastic elastomer according to claim 8 , wherein the melting temperature of the thermoplastic elastomer is at least 200° C.
10. The thermoplastic elastomer according to claim 6 , wherein the hard segments (a) comprise butylene terephthalate as repeating units.
11. The thermoplastic elastomer according to claim 6 , wherein the soft segments (b) comprise repeating units represented by Formula I:
where R=H and/or alkyl; and
X=2-20.
12. A process for forming a blow-molded article which comprises blow molding a polymer composition comprising the thermoplastic elastomer according to claim 6 .
13. The process according to claim 12 , wherein the process is suction blow molding.
14. A shaped object comprising the thermoplastic elastomer according to claim 6 , wherein the shaped object is an air duct, a corrugated tube for the production of jounce bumpers or a cover for a constant velocity joint.