POLYESTER-BASED POLYMERS HAVING IMPROVED HYDROLYTIC STABILITY

Abstract

The present invention relates to a polymer obtainable by reaction of a polyester comprising a quantity of carboxylic terminal groups with a chain extending compound wherein the chain extending compound is selected from an aromatic bis(oxirane ether) or an aromatic bis(methyloxirane ether). Such polymer may have a desired resistance to hydrolytic degradation.

Claims

1. A polymer obtained by reaction of a polyester comprising a quantity of carboxylic terminal groups with a chain extending compound, wherein the chain extending compound is selected from an aromatic bis(oxirane ether) an aromatic bis(methyloxirane ether), or a combination thereof.

2. The polymer according to claim 1, wherein the chain extending compound is selected from 2,2-methylene-bis(4,1-phenyleneoxy)bisoxirane, 2,2-ethylidene-bis(4,1-phenyleneoxy)bisoxirane, 2,2-(1-methylethylidene)-bis(4,1-phenyleneoxy)bisoxirane, 2,2-ethylidene-bis(4,1-phenyleneoxy)bisoxirane, 2,2-(1-methylethylidene)-bis(4,1-phenyleneoxy)bis(3-methyl-oxirane), 4,4-bis(1,2-epoxypropoxy)biphenyl, 2,2-((1,1-biphenyl])-4,4-diylbis(oxy))bisoxirane, 1,4-bis(1,2-epoxypropoxy)benzene, 2,2-(1,4-phenylenebis(oxy)bisoxirane, 2,2-((1,1-binaphthalene)-2,2-diylbis(oxy))bisoxirane, ((6-oxiranylmethoxy(2,2-binaphthalene)-6-yl)oxy)oxirane, 2,2-(1,6-naphthalenediylbis(oxy))bisoxirane, 2,2-((1,1-biphenyl)-4,4-diylbis(oxy))bis(2-methyl-oxirane), 2,2-(2,6-naphthalenediylbis(oxy))bis(2-methyl-oxirane), 2,2-(methylenebis(4,1-phenyleneoxy))bis(2-methyl-oxirane), 2,2-(1,4-phenylenebis(oxy))bis(2-methyl-oxirane), (2-methyl-4-((oxiranyloxy)methyl)phenoxy)oxirane, (2,6-dimethyl-4-((oxiranyloxy)methyl)phenoxy)oxirane, or a combination thereof.

3. The polymer according to claim 1, wherein the chain extending compound is 2,2-(1-methylethylidene)-bis(4,1-phenyleneoxy)bisoxirane.

4. The polymer according to claim 1, wherein the chain extending compound is added to the reaction of the polyester and the chain extending compound in a quantity of 0.5 and 8.0 wt % with regard to the total weight of the polyester and the chain extending compound.

5. The polymer according to claim 1, wherein the polymer comprises units according to formula I: ##STR00007## wherein R1 is selected from CH.sub.2CH.sub.2, CH.sub.2CH.sub.2CH.sub.2, or CH.sub.2CH.sub.2CH.sub.2CH.sub.2; and 0.03 mol of units according to formula III: ##STR00008## per mol of units according to formula I.

6. The polymer according to claim 1, wherein the reaction takes place in the presence of a catalyst selected from: an oxide selected from zinc oxide, magnesium oxide, titanium oxide, or antimony trioxide; a borate selected from zinc borate, calcium borate, sodium tetraphenylborate, tetrabutyl ammonium tetraphenylborate, trioctanol borate or triethanol borate; a phosphate selected from zinc phosphate, calcium phenyl phosphate, calcium hydroxyapatite, aluminium phosphate, or zinc diethylphosphinate; or a carboxylate selected from sodium acetate, zinc acetate, magnesium stearate, calcium stearate, sodium stearate or zinc stearate.

7. The polymer according to claim 6 wherein the catalyst is a carboxylate selected from sodium acetate, zinc acetate, magnesium stearate, calcium stearate, sodium stearate or zinc stearate.

8. The polymer according to claim 1, wherein the catalyst is added to the reaction of the polyester and the chain extending compound in a quantity of 0.01 and 0.25 wt % with regard to the total weight of the polyester and the chain extending compound in the reaction.

9. The polymer according to claim 1, wherein the polyester is selected from poly(ethylene terephthalate), poly(propylene terephthalate), poly(ethylene naphthanoate), or poly(butylene terephthalate).

10. The polymer according to claim 1, wherein the polyester is poly(butylene terephthalate), wherein the poly(butylene terephthalate) has: a carboxylic end group content as determined in accordance with ASTM D7409-15 of 5 and 100 mmol/g; and/or an intrinsic viscosity of 0.50 and 2.00 dl/g as determined in accordance with ASTM D2857-95 (2007).

11. The polymer according to claim 1, having a complex viscosity as determined via dynamic mechanical spectroscopy (DMS) at 1 rad/s of 1200 Pa.Math.s.

12. A polymer composition comprising a polymer according to claim 1, wherein the polymer composition further comprises: 5.0-40.0 wt % of glass fibres; and/or 0.0-10.0 wt % of linear low-density polyethylene having a density of 905 and 930 kg/m.sup.3 as determined in accordance with ISO 1183-1 (2012) with regard to the total weight of the polymer composition.

13. The polymer composition according to claim 12 wherein the polymer composition comprises 50.0 and 90.0 wt % of a polymer according to claim 1, with regard to the total weight of the polymer composition.

14. A process for the preparation of a polymer according to claim 1, comprising subjecting the polyester and the chain extender to melt mixing in a melt extruder wherein the temperature in the volume of space in the area between the tip(s) of the extruder screw(s) and the opening(s) for removing the obtained polymer composition is 250-260 C.

15. The process according to claim 14 wherein the residence time of the polyester in the melt extruder is 15-45 seconds.

16. The polymer according to claim 5, wherein the polyester is poly(butylene terephthalate), wherein the poly(butylene terephthalate) has: a carboxylic end group content as determined in accordance with ASTM D7409-15 of 5 and 100 mmol/g; and/or an intrinsic viscosity of 0.50 and 2.00 dl/g as determined in accordance with ASTM D2857-95 (2007).

17. The polymer according to claim 5, having a complex viscosity as determined via dynamic mechanical spectroscopy (DMS) at 1 rad/s of 1200 Pa.Math.s.

18. A polymer composition comprising a polymer according to claim 5, wherein the polymer composition further comprises: 5.0-40.0 wt % of glass fibres; and/or 0.0-10.0 wt % of linear low-density polyethylene having a density of 905 and 930 kg/m.sup.3 as determined in accordance with ISO 1183-1 (2012) with regard to the total weight of the polymer composition.

19. A polymer, comprising units according to formula I: ##STR00009## wherein R1 is selected from CH.sub.2CH.sub.2, CH.sub.2CH.sub.2CH.sub.2, CH.sub.2CH.sub.2CH.sub.2CH.sub.2; and 0.03 mol of units according to formula III: ##STR00010## per mol of units according to formula I.

Description

[0105] The invention will now be illustrated by the following non-limiting examples.

[0106] For the preparation of samples illustrating the present invention, the materials as listed in table 1 were used.

TABLE-US-00001 TABLE 1 Materials used in preparation of exemplary samples Valox 195 Poly(butylene terephthalate) obtainable from SABIC having a carboxylic end group content as determined in accordance with ASTM D7409-15 of 17 mmol/g and an intrinsic viscosity of 0.57 dl/g as determined in accordance with ASTM D2857-95 (2007), and a number average molecular weight Mn of 17.5 kg/mol. Valox 315 Poly(butylene terephthalate) obtainable from SABIC having a carboxylic end group content as determined in accordance with ASTM D7409-15 of 38 mmol/g and an intrinsic viscosity of 1.20 dl/g as determined in accordance with ASTM D2857-95 (2007), and a number average molecular weight Mn of 36.5 kg/mol. Cycloepoxy (3,4-Epoxycyclohexyl)methyl 3,4-epoxycyclo- hexylcarboxylate, CAS registry nr. 2386-87-0 BPA epoxy 2,2-(1-methylethylidene)-bis(4,1-phenyleneoxy)bisoxirane, CAS registry nr. 1675-54-3 GF Glass fibre Stab Hindered phenol stabilizer, pentaerythritol-tetrakis(3-(3,5- di-tert-butyl-4-hydroxyphenyl) propionate), CAS registry nr. 6683-19-8 Cat Sodium stearate, CAS registry nr. 822-16-2 LLDPE Linear low density polyethylene of grade DNDA-8320NT7 from Ravago

[0107] In an Entek 27 mm melt extruder, polymer compositions were produced according to the material formulations as listed in table 2:

TABLE-US-00002 TABLE 2 Material formulations of exemplary samples Example 1 2 3 4 (C) 5 (C) 6 (C) Valox 315 20.00 20.00 20.00 20.00 20.00 20.00 Valox 195 44.06 43.21 41.51 44.06 43.21 41.51 Cycloepoxy 0.85 1.70 3.40 BPA epoxy 0.85 1.70 3.40 GF 30.00 30.00 30.00 30.00 30.00 30.00 Stab 0.04 0.04 0.04 0.04 0.04 0.04 Cat 0.05 0.05 0.05 0.05 0.05 0.05 LLDPE 5.00 5.00 5.00 5.00 5.00 5.00

[0108] The values presented in table 2 indicate parts by weight.

[0109] The material formulations of examples 1-3 reflect the present invention. The material formulations of examples 4-6 are included for comparative purposes.

[0110] Of the polymers compositions produced according to the material formulations of table 2, material properties were determined. For certain properties, the values were determined after the preparation of the samples, as well as after 250 hours and/or 500 hours of exposure to a temperature of 80 C. at 70% relative humidity. The results are presented in table 3.

TABLE-US-00003 TABLE 3 Material properties of exemplary polymer compositions Example 1 2 3 4 (C) 5 (C) 6 (C) MVR 34.1 38.3. 31.4 35.0 52.0 65.0 MVR.sub.250 31.2 29.1 32.6 54.0 73.0 85.0 MVR.sub.250 8.5 24.0 +3.8 +53.0 +40.0 +31.0 MVR.sub.500 46.0 38.2 32.5 166.0 101.0 75.0 MVR.sub.500 +34.9 0.3 +3.5 +373 +94 +15 TM 9042 9098 9250 9336 8930 8286 TM.sub.250 9063 9133 9197 9277 9033 8423 TM.sub.250 +0.2 +0.4 0.6 0.6 +1.2 +1.7 TM.sub.500 9200 9270 9360 9393 9123 8667 TM.sub.500 +1.7 +1.9 +1.2 +0.6 +2.2 +4.6 TS 123 127 131 122 121 113 TS.sub.250 126 130 131 124 126 121 TS.sub.250 +2.4 +2.4 0.0 +1.6 +4.1 +7.1 TS.sub.500 124 130 128 123 122 115 TS.sub.500 +0.8 +2.4 2.3 +0.8 +0.8 +1.8 Izod 103 102 101 93.2 88.8 85.5 Izod.sub.250 90.8 94.5 88.6 80.6 78.5 74.8 Izod.sub.250 11.9 7.3 12.2 13.5 11.6 12.6 Izod.sub.500 88.1 96.8 88.1 80.8 74.1 70.8 Izod.sub.500 14.5 5.1 12.8 13.3 16.6 17.2 CV 2350 3800 1570 1030 1080 480

[0111] Wherein:

[0112] MVR is the melt volume flow rate as determined in accordance with ISO 1133-1 (2011) at 250 C. under a load of 5 kg, expressed in cm.sup.3/10 min. MVR was determined upon preparation of the samples. MVR.sub.250 is the melt volume flow rate determined after 250 hours of exposure as indicated above. MVR.sub.500 is the melt volume flow rate after 500 hours of exposure. MVR.sub.250 is the change in melt volume flow rate between the MVR and the MVR.sub.250, expressed in %. MVR.sub.500 is the change in melt volume flow rate between the MVR and the MVR.sub.500, expressed in %.

[0113] TM is the tensile modulus as determined in accordance with ISO 527-1 (2012), expressed in MPa. TM was determined upon preparation of the samples. TM.sub.250 is the tensile modulus after 250 hours of exposure. TM.sub.500 is the tensile modulus after 500 hours of exposure. TM.sub.250 is the change in tensile modulus between the TM and the TM.sub.250, expressed in %. TM.sub.500 is the change in tensile modulus between the TM and the TM.sub.500, expressed in %.

[0114] TS is the tensile strength at yield as determined in accordance with ISO 527-1 (2012), expressed in MPa. TS was determined after preparation of the samples. TS.sub.250 is the tensile strength after 250 hours of exposure. TS.sub.500 is the tensile strength after 500 hours of exposure. TS.sub.250 is the change in tensile strength between the TS and the TS.sub.250, expressed in %. TS.sub.500 is the change in tensile modulus between the TS and the TS.sub.500, expressed in %.

[0115] Izod is the notched Izod impact strength as determined in accordance with ISO 180 (2000), notch type A, at 23 C., expressed in J/m. Izod was determined upon preparation of the samples. Izod.sub.250 is the Izod impact strength after 250 hours of exposure. Izod.sub.500 is the Izod impact strength after 500 hours of exposure. Izod.sub.250 is the change in Izod impact strength between Izod and Izod.sub.250. Izod.sub.500 is the change in Izod impact strength between Izod and Izod.sub.500.

[0116] CV is the complex viscosity as determined via DMS at an angular frequency of 1 rad/s, expressed in Pa.Math.s. For determining the DMS spectrum, an ARES G2 rheometer was used at 200 C. measuring at frequencies of 0.01 rad/s to 100 rad/s, at a linear viscoelastic strain of 5%, using plates of 0.5 mm thickness produced according to ISO 1872-2 (2007).

[0117] From the above presented examples, it becomes apparent that polymers according to the present invention have reduced tendency to degrade when subjected to exposure to a certain high temperature and humidity for a certain time, such as upon exposure to a temperature of 80 C. at 70% relative humidity for 250 hours or 500 hours.

[0118] The experiments demonstrate that the tensile strength of the polymer compositions is maintained for each of the examples. The TS.sub.250 and the TS.sub.500 are for each of the examples close to of even above 0, indicating no loss of tensile strength during the exposure period. In absolute terms, the tensile strength of the examples according to the invention is higher than of the comparative examples.

[0119] This is also the case for the Izod impact strength. Comparing each of the experimental pairs 1 and 4, 2 and 5, and 3 and 6, shows that the Izod impact strength of the examples according to the invention is higher than of the comparative examples. With respect to retention of Izod impact strength after a given period of exposure, the examples according to the invention demonstrate at least an equal level of retention, which means that even after exposure, the Izod impact strength of the examples according to the invention is still higher than of the comparative examples.

[0120] Furthermore, in particular in the case of example 2, which represents an example of a polymer obtained by reaction of a polyester comprising a quantity of carboxylic terminating groups with a chain extending compound wherein the chain extending compound is selected from an aromatic bis(oxirane ether) or an aromatic bis(methyloxirane ether) wherein the chain extending compound is added in a quantity of 1.0 ands 2.5 wt % with regard to the total weight of the base polyester to the reaction of the base polyester and the chain extending compound, it is demonstrated that the use of the chain extending compound in such particular quantities may contribute to a desirably high complex viscosity, a good retention of the MVR after a lengthy exposure such as 500 hours, and a good retention of the Izod impact strength.