WO2017063849A1

WO2017063849A1 - Polyether ester block copolymers

Info

Publication number: WO2017063849A1
Application number: PCT/EP2016/072677
Authority: WO
Inventors: Suman Kumar SEN; Abbas-Alli Ghudubhai Shaikh; Susanta MITRA; Stephen Park
Original assignee: Sabic Global Technologies B.V.
Priority date: 2015-10-12
Filing date: 2016-09-23
Publication date: 2017-04-20

Abstract

The present invention relates to a polyether ester block copolymer comprising: (I) hard block moieties formed by reacting one or more aromatic dicarboxylic acid comprising 6-12 carbon atoms and/or the C1-C4 diester thereof with one or more aliphatic diol comprising 2-10 carbon atoms; (II) soft block moieties formed by reacting one or more aromatic dicarboxylic acid comprising 6-12 carbon atoms and/or the C1-C4 diester thereof with one or more polyalkylene glycol comprising 2-10 carbon atoms in the repeating polymeric unit; (III) soft block moieties formed by reacting one or more aromatic dicarboxylic acid comprising 6-12 carbon atoms and/or the C1-C4 diester thereof with one or more hydroxy-terminated polysiloxane or a copolymer thereof; wherein the weight ratio of soft block (II) to soft block (III)≥ 8.0 and < 12.0; the weight of the fraction of soft block (III)≥ 0.5 and < 6.0 % by weight with regard to the total weight of the polyether ester block copolymer; the weight of the fraction of soft block (II)≥ 10.0 and < 50.0 % by weight with regard to the total weight of the polyether ester block copolymer. Such polyether ester block copolymers may for example have good properties relating to resistance to water, for example good hydrophobicity and good resistance to hydrolysis, as well as good thermal properties and good mechanical properties.

Description

Polyether ester block copolymers

The present invention relates to polyether ester block copolymers having an improved balance of mechanical properties, surface hydrophobicity and hydrothermal stability, a process for the production thereof, and articles made using such block copolymers.

Polyether ester block copolymers are a class of thermoplastic materials exhibiting elastomeric properties. Primarily because of their easy processability coupled with good thermo- mechanical properties, polyether ester block copolymers have found wide ranges of applications in many industrial branches including but not limited to automotive components, sporting goods, hose, cable jacketing, seals, and shoe soles.

For certain applications, however, the hydrophobicity and resistance to hydrolysis of polyether ester block copolymers according to the state of the art is insufficient. Various options have been tried to improve these, but these solutions did not present a desired balance of thermal properties such as melting temperature and crystallisation temperature, mechanical properties such as tensile strength, tensile stress and elongation at break, and properties relating to the resistance to water, such as surface hydrophobicity and resistance to hydrolysis.

For example, US5236979 presents the addition of a mixture of

tris(hydroxybenzyl)benzene and bis(alkylphenyl)pentaerythritol diphosphate stabilisers to polyether ester block copolymers.

Another option has been suggested by EP647674A1 , which presents the addition of epoxy compounds such as bisphenol-based epoxy compounds in combination with organic phosphites to polyether ester block copolymers.

However, none of these solutions provide a desired balance of properties, where the properties relating to resistance to water are improved, whereas the mechanical and thermal properties are not negatively influenced.

The above clearly presents a need for the development of polyether esters block copolymers having improved hydrophobicity and resistance to hydrolysis, whilst maintaining thermal properties and mechanical properties. This has now been achieved according to the present invention by a polyether ester block copolymer that comprises: (I) hard block moieties formed by reacting one or more aromatic dicarboxylic acid comprising 6-12 carbon atoms and/or the C1-C4 diester thereof with one or more aliphatic diol comprising 2-10 carbon atoms;

(II) soft block moieties formed by reacting one or more aromatic dicarboxylic acid comprising 6-12 carbon atoms and/or the C1-C4 diester thereof with one or more polyalkylene glycol having a polymeric structure comprising alkylene oxide units having 2-10 carbon atoms;

(III) soft block moieties formed by reacting one or more aromatic dicarboxylic acid comprising 6-12 carbon atoms and/or the C1-C4 diester thereof with one or more hydroxy-terminated polysiloxane or a copolymer thereof; wherein

• the weight ratio of soft block (II) to soft block (III)≥ 8.0 and < 12.0;

• the weight of the fraction of soft block (III)≥ 0.5 and < 6.0 % by weight with regard to the total weight of the polyether ester block copolymer;

• the weight of the fraction of soft block (II)≥ 10.0 and < 50.0 % by weight with regard to the total weight of the polyether ester block copolymer.

In an embodiment, the weight of the fraction of soft block (III) may be≥ 0.5 and < 4.0 weight % with regard to the total weight of the polyether ester block copolymer.

Preferably, hard block moieties (I) are moieties formed by reacting one or more aromatic dicarboxylic acid comprising 6-12 carbon atoms and/or the C1-C4 diester thereof with one or more aliphatic diol comprising 2-10 carbon atoms.

Further preferably, soft block moieties (II) are moieties formed by reacting one or more aromatic dicarboxylic acid comprising 6-12 carbon atoms and/or the C1-C4 diester thereof with one or more polyalkylene glycol having a polymeric structure comprising alkylene oxide units having 2-10 carbon atoms.

Also further preferably, soft block moieties (III) are moieties formed by reacting one or more aromatic dicarboxylic acid comprising 6-12 carbon atoms and/or the C1-C4 diester thereof with one or more hydroxy-terminated polysiloxane or a copolymer thereof.

Particularly preferably, hard block moieties (I) are moieties formed by reacting one or more aromatic dicarboxylic acid comprising 6-12 carbon atoms and/or the C1-C4 diester thereof with one or more aliphatic diol comprising 2-10 carbon atoms; soft block moieties (II) are moieties formed by reacting one or more aromatic dicarboxylic acid comprising 6-12 carbon atoms and/or the C1-C4 diester thereof with one or more polyalkylene glycol having a polymeric structure comprising alkylene oxide units having 2-10 carbon atoms; and soft block moieties (III) are moieties formed by reacting one or more aromatic dicarboxylic acid comprising 6-12 carbon atoms and/or the C1-C4 diester thereof with one or more hydroxy-terminated polysiloxane or a copolymer thereof.

Such polyether ester block copolymers may for example have good properties relating to resistance to hot water, for example good hydrophobicity and good resistance to hydrolysis, as well as good thermal properties and good mechanical properties. Such polyether ester block copolymers may for example have a reduced crystallisation temperature. Such reduced crystallisation temperature may for example result in a higher degree of crystallisation. Such higher degree of crystallisation may for example result in an increased tensile strength.

The polyether ester block copolymers according to the present invention may for example be prepared by a polycondensation process. Such polycondensation process may for example be performed in a reactor. Such polycondensation process may for example be a melt process, in which the reactants are present in the molten state. Such polycondensation process may for example comprise two reaction steps. Such polycondensation process comprising two reaction steps may comprise a first step and a second step, wherein the first step preceeds the second step. In the case where the polycondensation takes place in a polycondensation process comprising a first and a second step, in which a reaction mixture comprising one or more aromatic dicarboxylic acid comprising 6-12 carbon atoms is used, an esterification reaction takes place in the first step. In the case where the polycondensation takes place in a

polycondensation process comprising a first and a second step in which a reaction mixture comprising a C1-C4 diester of one or more aromatic dicarboxylic acid comprising 6-12 carbon atoms is used, a transesterification reaction takes place in the first step. In the second step, a transesterification reaction takes place.

In the first step, a quantity of the reactants having hydroxyl-functional groups may react with a quantity of the reactants having carboxylic acid or ester functional groups. The acid or ester functional groups of the one or more aromatic dicarboxylic acid and/or the diester thereof may react with the hydroxyl-functional moieties of the one or more diol, the one or more polyalkylene glycol and/or the hydroxyl-terminated polysiloxane to form ester moieties.

Such first step may for example be operated at atmospheric pressure. A catalyst may be introduced during the first step. Such catalyst may for example be selected from organo-titanium compounds, alkyl titanates, alkyl tin compounds, cobalt acetates, antimony acetates, zinc acetates, manganese acetates, magnesium acetates, calcium acetates and/or mixtures thereof.

In the second step, the polyether ester block copolymers may be formed by

transesterification of the reaction mixture obtained from the first step. The second step may for example be operated at reduced pressure, for example at pressures < 200 mbar, alternatively < 100 mbar. The second step may for example comprise two or more stages, in which in the first stage the pressure may for example be kept at < 200 mbar, alternatively < 100 mbar, and in which in a second stage the pressure may for example be further reduced to < 1 mbar, alternatively < 0.1 mbar. The first step and the second step may be performed in a single reactor.

In an embodiment, the present invention relates to a process for the production of polyether ester block copolymers by reacting in a polycondensation process comprising two reaction steps a mixture of reactants comprising:

• one or more aromatic dicarboxylic acid selected from terephthalic acid,

isophthalic acid, dimethyl terephthalate, dimethyl isophthalate, diethyl terephthalate, diethyl isophthalate or combinations thereof;

• one or more aliphatic diol selected from 1 ,2-ethanediol, 1 ,2-propanediol, 1 ,3- propanediol, 1 ,2-butanediol, 1 ,3-butanediol, 1 ,4-butanediol or combinations thereof;

· one or more polyalkylene glycol selected from polyethyleneglycol, polypropyleneglycol, polytetramethyleneetherglycol, or combinations thereof; and

• one or more hydroxy-terminated polysiloxane selected from hydroxy- terminated polydimethylsiloxanes.

wherein the first step is operated at atmospheric pressure, and the second step is operated at a pressure of < 200 mbar

The polyether ester block copolymer may for example comprise≥ 50.0 % by weight, alternatively≥ 60.0 % by weight, alternatively≥ 70.0 % by weight, of hard block moieties (I), compared to the total weight of the polyether ester block copolymer. For example, the polyether ester block copolymer may comprise < 89.5 % by weight, alternatively < 85.0 % by weight, alternatively < 80.0 % by weight, of hard block moieties (I), compared to the total weight of the polyether ester block copolymer. For example, the polyether ester block copolymer may comprise≥ 50.0 and < 89.5 % by weight, alternatively≥ 60.0 and < 85.0 % by weight, alternatively≥ 70.0 and < 80.0 % by weight, of hard block moieties (I), compared to the total weight of the polyether ester block copolymer.

The polyether ester block copolymer may for example comprise≥ 10.0 % by weight, alternatively≥ 15.0 % by weight, alternatively≥ 20.0 % by weight, of soft block moieties (II), compared to the total weight of the polyether ester block copolymer. For example, the polyether ester block copolymer may comprise < 50.0 % by weight, alternatively < 40.0 % by weight, alternatively < 30.0 % by weight, of soft block moieties (II), compared to the total weight of the polyether ester block copolymer. For example, the polyether ester block copolymer may comprise≥ 10.0 and < 50.0 % by weight, alternatively≥ 15.0 and < 40.0 % by weight, alternatively≥ 20.0 and < 30.0 % by weight, of soft block moieties (II).

The polyether ester block copolymer may for example comprise≥ 0.5 % by weight, alternatively≥ 1 .0 % by weight, alternatively≥ 1 .5 % by weight, of soft block moieties (III), compared to the total weight of the polyether ester block copolymer. For example, the polyether ester block copolymer may comprise < 6.0 % by weight, alternatively < 5.0 % by weight, alternatively < 4.0 % by weight, alternatively < 3.0 % by weight, of soft block moieties (III), compared to the total weight of the polyether ester block copolymer. For example, the polyether ester block copolymer may comprise≥ 0.5 and < 6.0 % by weight, alternatively≥ 0.5 and < 5.0 % by weight, alternatively≥ 0.5 and < 4.0 % by weight, alternatively≥ 1 .0 and < 3.0 % by weight, of soft block moieties (III), compared to the total weight of the polyether ester block copolymer.

In an embodiment, the polyether ester block copolymer may comprise≥ 0.5 and < 6.0 % by weight of soft block moieties (III) compared to the total weight of the polyether ester block copolymer. In another embodiment, the polyether ester block copolymer may comprise≥ 0.5 and < 4.0 % by weight of soft block moieties (III) compared to the total weight of the polyether ester block copolymer.

In one embodiment of the invention, the polyether ester block copolymer comprises:

(I) ≥ 49.5 and < 89.5 % by weight with regard to the total weight of the polyether ester block copolymer of hard block moieties formed by reacting one or more aromatic dicarboxylic acid comprising 6-12 carbon atoms and/or the C1-C4 diester thereof with one or more aliphatic diol comprising 2-10 carbon atoms; (II)≥ 10.0 and < 50.0 % by weight with regard to the total weight of the polyether ester block copolymer of soft block moieties formed by reacting one or more aromatic dicarboxylic acid comprising 6-12 carbon atoms and/or the C1-C4 diester thereof with one or more polyalkylene glycol having a polymeric structure comprising alkylene oxide units having 2-10 carbon atoms;

(II I)≥ 0.5 and < 6.0 % by weight with regard to the total weight of the polyether ester block copolymer of soft block moieties formed by reacting one or more aromatic dicarboxylic acid comprising 6-12 carbon atoms and/or the C1-C4 diester thereof with one or more hydroxy-terminated polysiloxane or a copolymer thereof.

For example, the weight ratio of soft block (II) to soft block (III) may be≥ 8.0, alternatively ≥ 9.0. For example, the weight ratio of soft block (II) to soft block (III) may be < 12.0, alternatively < 1 1.0. For example, the weight ratio of soft block (II) to soft block (III) may be≥ 8.0 and < 12.0, alternatively≥ 9.0 and < 1 1.0.

The hard block moieties (I) as present in the polyether ester block copolymers of the present invention may for example comprise poly(alkylene arylate) moieties. Such poly(alkylene arylate) moieties may for example be selected from poly(ethylene terephthalate), poly(butylene terephthalate), poly(propylene terephthalate), poly(ethylene naphthanoate), poly(propylene naphthanoate), poly(butylene naphthanoate), and/or poly(ethylene terephthalate)(butylene terephthalate). For example, the poly(alkylene arylate) moieties may be poly(ethylene terephthalate). For example, the poly(alkylene arylate) moieties may be poly(butylene terephthalate). For example, the poly(alkylene arylate) moieties may be poly(ethylene terephthalate)(butylene terephthalate).

The one or more aromatic dicarboxylic acid comprising 6-12 carbon atoms and/or the Ci- C₄ diester thereof may for example be one or more selected from isophthalic acid, terephthalic acid, 1 ,4-naphthalene dicarboxylic acid, 1 ,5-naphthalenedicarboxylic acid, 2,6- naphthalenedicarboxylic acid, dimethyl terephthalate, diethyl terephthalate, dimethyl isophthalate, diethyl isophthalate, dimethyl-1 ,4-naphthalenedicarboxylate, dimethyl-1 ,5- naphthalenedicarboxylate, and/or dimethyl-2,6-naphthalenedicarboxylate. For example, the aromatic dicarboxylic acid comprising 6-12 carbon atoms and/or the C1-C4 diester thereof may be one or more selected from terephthalic acid, isophthalic acid, dimethyl terephthalate, and/or dimethyl isophthalate. For example, the aromatic dicarboxylic acid comprising 6-12 carbon atoms and/or the C1-C4 diester thereof may be terephthalic acid and/or dimethyl terephthalate.

The one or more aliphatic diol comprising 2-10 carbon atoms may for example be one or more selected from 1 ,2-ethanediol, 1 ,2-propanediol, 1 ,3-propanediol, 1 ,2-butanediol, 1 ,3- butanediol and/or 1 ,4-butanediol.

In an embodiment, the polyether ester block copolymer is obtained by reacting a mixture of reactants comprising a first and a second aliphatic diol each having a different molecular composition.

In an embodiment, the first and the second aliphatic diol are each selected from 1 ,2- ethanediol, 1 ,2-propanediol, 1 ,3-propanediol, 1 ,2-butanediol, 1 ,3-butanediol and 1 ,4-butanediol.

In an embodiment, the first aliphatic diol is 1 ,2-ethanediol and the second aliphatic diol is 1 ,4-butanediol.

In an embodiment, the quantity of the first and the second aliphatic diol is such as to result in a polyether ester block copolymer in which the ratio of the weight of the fraction of the hard blocks derived from the first aliphatic diol to the weight of the fraction of hard blocks derived from the second aliphatic diol is≥ 0.2 and < 2.0.

The one or more polyalkylene glycol having a polymeric structure comprising alkylene oxide units having 2-10 carbon atoms may for example be one or more selected from

polyethyleneglycol, polypropyleneglycol and/or polytetramethyleneetherglycol. The polyalkylene glycol may for example have a number average molecular weight M_n as determined in accordance with ASTM D5296-1 1 of≥ 500 g/mol, alternatively≥ 1000 g/mol. The polyalkylene glycol may for example have a number average molecular weight M_n of < 2500 g/mol, alternatively < 2000 g/mol. For example, the polyalkylene glycol may have a number average molecular weight M_n of≥ 500 and < 2500 g/mol, alternatively≥ 1000 and < 2000 g/mol.

In an embodiment, wherein the polyalkylene glycol has a number average molecular weight M_n as determined according to ASTM D5296-1 1 of≥ 500 and < 2500 g/mol. The hydroxy-terminated polysiloxane may for example be a polysiloxane according to the formula I: Rl

!

HO R2 0— f- SJ— 04- R2— OH

^' !

Rl

Formula I

Wherein

R1 may be an alkyl moiety such as methyl, ethyl or propyl, for example methyl.

R2 may each individually be an alkyl moiety or a dialkyl ether moiety such as a dimethyl ether moiety, a diethyl ether moiety, a methyl ethyl ether moiety, or an ethyl propyl ether moiety. For example, each R2 may be an ethyl propyl ether moiety wherein the ethyl group of the ethyl propyl moiety is connected to the terminal hydroxyl-moiety of the hydroxy-terminated

polysiloxane.

n may be≥ 5 and < 30.

For example, the hydroxy-terminated polysiloxane may be a polysiloxane according to formula I wherein each R2 is an ethyl propyl ether moiety of which the ethyl moiety is connected to the terminal hydroxyl-moiety, each R1 is methyl, and n≥ 5 and < 30.

The hydroxy-terminated polysiloxane may for example have an average number of recurring siloxane polymeric units of≥ 5 and < 30.

The one or more hydroxy-terminated polysiloxane may for example be a hydroxy- terminated polydimethyl siloxane or a copolymer thereof.

In an embodiment, the polysiloxane has an average number of repeating polymeric units of≥ 5 and < 30.

The polyether ester block copolymer may for example comprise:

(I) hard block moieties formed by reacting one of terephthalic acid or dimethyl terephthalate with one or more aliphatic diol comprising 1 ,4-butanediol;

(II) soft block moieties formed by reacting one of terephthalic acid or dimethyl terephthalate with one or more polyalkylene glycol comprising polytetramethylene ether glycol and/or polyethylene glycol;

(III) soft block moieties formed by reacting one of terephthalic acid or dimethyl terephthalate with a hydroxy-terminated polydimethylsiloxane wherein

• the weight ratio of soft block (II) to soft block (III) may be≥ 8.0 and < 12.0; • the weight of the fraction of soft block (III) may be≥ 0.5 and < 4.0 % by weight with regard to the total weight of the polyether ester block copolymer;

• the weight of the fraction of soft block (II) may be≥ 10.0 and < 50.0 % by weight with regard to the total weight of the polyether ester block copolymer.

In an embodiment, the invention relates to a polyether ester block copolymer wherein:

• the one or more aromatic dicarboxylic acid comprising 6-12 carbon atoms

and/or the C1-C4 diester thereof may be one or more selected from terephthalic acid, isophthalic acid, 1 ,4-naphthalenedicarboxylic acid, 1 ,5- naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, dimethyl terephthalate, dimethyl isophthalate, or combinations thereof; and/or

• the one or more aliphatic diol may be one or more selected from 1 ,2- ethanediol, 1 ,2-propanediol, 1 ,3-propanediol, 1 ,2-butanediol, 1 ,3-butanediol, 1 ,4-butanediol or combinations thereof; and/or

· the one or more polyalkylene glycol may be one or more selected from

polyethyleneglycol, polypropyleneglycol, polytetramethyleneetherglycol, or combinations thereof; and/or

• the one or more hydroxy-terminated polysiloxane may be an hydroxy- terminated polydimethylsiloxane or a copolymer thereof.

In an embodiment, the invention relates to a process wherein the mixture of reactants may comprise:

• 10-40% by weight of a first aliphatic diol selected from 1 ,2-ethanediol, 1 ,2- propanediol, 1 ,3-propanediol, 1 ,2-butanediol, 1 ,3-butanediol, 1 ,4-butanediol; and

• 60-90 % by weight of a second aliphatic diol selected from 1 ,2-ethanediol, 1 ,2- propanediol, 1 ,3-propanediol, 1 ,2-butanediol, 1 ,3-butanediol, 1 ,4-butanediol; with regard to the total weight of the aliphatic diol in the reaction mixture;

wherein the second aliphatic diol has a higher molecular weight than the first aliphatic diol. In an embodiment, the invention may relate to a process wherein the weight ratio of the first aliphatic diol to the second aliphatic diol may be≥ 0.5 and < 1.5.

The reaction may take place in the presence of 0.10 - 1.00 % of by weight of a catalyst with regard to the total weight of the one or more aromatic dicarboxylic acid comprising 6-12 carbon atoms and/or the C1-C4 diester thereof. Such catalyst may for example be selected from organo-titanium compounds, alkyl titanates, alkyl tin compounds, cobalt acetates, antimony acetates, zinc acetates, manganese acetates, magnesium acetates, calcium acetates and/or mixtures thereof. Such catalyst may for example comprise a titanium (IV) alkoxide. Such titanium (IV) alkoxide may for example be selected from titanium (IV) tetraisopropoxide and/or titanium (IV) tetrabutoxide.

Such catalyst may for example be present in quantities≥ 0.05 % by weight, alternatively≥ 0.10 % by weight, alternatively≥ 0.15 % by weight, with regard to the total weight of the one or more aromatic dicarboxylic acid comprising 6-12 carbon atoms and/or the C1-C4 diester thereof. Such catalyst may for example be present in quantities < 1.00 % by weight, alternatively < 0.50 % by weight, alternatively < 0.30 % by weight, with regard to the total weight of the one or more aromatic dicarboxylic acid comprising 6-12 carbon atoms and/or the C1-C4 diester thereof.

Such catalyst may for example be present in quantities≥ 0.05 % and < 1.00 % by weight, alternatively≥ 0.10 % and < 0.50 % by weight, alternatively≥ 0.15 % and < 0.30 % by weight, with regard to the total weight of the one or more aromatic dicarboxylic acid comprising 6-12 carbon atoms and/or the C1-C4 diester thereof.

In an embodiment, the present invention also relates to compositions comprising a polyether ester block copolymer in which the composition may further comprise fibrous or particulate fillers, antioxidants and/or colorants. The fibrous filler may be for example carbon, glass or mineral fibers. The particulate filler may be for example calcium carbonate, wollastonite or mica or mixtures thereof. The antioxidant may for example be a sterically hindered phenolic compound, such as a monocyclic hindered phenol, a polycyclic hindered phenol bonded by a hydrocarbon group or a group containing a sulphur atom, and a hindered phenol having ester group or amide group. Examples of such antioxidants include 3,5-bis(1 ,1- dimethylethyl)-4- hydroxy-, 1 ,1 '-[2,2-bis[[3- [3,5-bis(1 ,1-dimethylethyl)-4-hydroxyphenyl]- 1 -oxopro- benzenepropanoic acid, 2,6-di-t-butyl-p-cresol, 2,2'-methylenebis(4-methyl-6-t-butylphenol), 4,4'-methylenebis(2,6-di-t-butylphenol), 1 ,1 ,3-tris(2-methyl-4-hydroxy-5-t-butylphenyl)butane, 4,4'-butylidenebis(3-methyl-6-t-butylphenol), 1 ,3-5-trimethyl-2-4,6-tris(3,5-di-t-butyl-4- hydroxybenzyl)benzene, 4,4'-thiobis(3-methyl-6-t-butylphenol), n-octadecyl-3-(4'-hydroxy-3',5'- di-t-butylphenyl)propionate, n-octadecyl-2-(4'-hydroxy-3',5'-di-t-butylphenyl)propionate, 1 ,6- hexanediol-bis[3-(3,5-di-t-butyl-4-hydroxphenyl)propionate], ethylenebis(oxyethylene)bis-[3-(5- tert-butyl-4-hydroxy-m-triyl) propionate], pentaerythritol tetrakis[3-(3,5-di-t-butyl-4- hydroxyphenyl)propionate], 3,9-bis[2- (3-(3-t-butyl-4-hydroxy-5-methylphenyl)-propionyloxy)-1 ,1 - dimethylethyl]-2,4,8,10-tetraoxaspiro-[5,5]undecane, butyl-6-(3'-t-butyl-5'-methyl-2'- hydroxybenzyl)-4-methylphenylacrylate, 2-[1-(2-hydroxy-3,5-di-t-pentylphenyl)ethyl]-4,6-di-t- pentylphenylacrylate, di-n-octadecyl-3,5-di-t-butyl-4-hydroxybenzylphosphonate, Ν,Ν'- hexamethylene bis-(3,5-di-t-butyl-4-hydroxy-dihydrocinnamamide, N,N'-ethylenebis[3-(3,5-di-t- butyl-4-hydroxyphenyl)-propionamide], Ν,Ν'-tetramethylene bis [3-(3,5-di-t-butyl-4- hydroxyphenyl)-propionamide], N,N'-hexamethylenebis[3-(3,5-di-t-butyl-4- hydroxyphenyl)propionamide], N,N'-ethylenebis[3-(3-t-butyl-5-methyl-4-hydroxyphenyl)- propionamide], N,N'-hexamethylenebis-[3-(3-t-butyl-5-methyl-4-hydroxyphenyl)propionamide], N,N'-bis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionyl] hydrazine, N,N'-bis[3-(3-t-butyl-5-methyl-4- hydroxphenyl)propyonyl]-hydrazine, 1 ,3,5-tris(3,5-di-t-butyl-4-hydroxybenzyl)isocyanurate, 1 ,3,5-tris(4-t-butyl-3-hydroxy-2,6-dimethylbenzyl)-isocyanurate, triethylene glycol bis(3-tert- butyl-4-hydroxy-5-methylphenyl)propionate. The antioxidant can comprise one of the aforementioned compounds or can be used in a combination comprising at least one of the foregoing. In an embodiment, the invention relates to an article comprising a polyether ester block copolymer. Such article may for example be flexible covers such as flexible joint covers, or dampening blocks.

A further particular embodiment of the invention relates to a polyether ester block copolymer comprising:

(I) hard block moieties formed by reacting one or more aromatic dicarboxylic acid comprising 6-12 carbon atoms and/or the C1-C4 diester thereof with one or more aliphatic diol comprising 2-10 carbon atoms;

(II) soft block moieties formed by reacting one or more aromatic dicarboxylic acid comprising 6-12 carbon atoms and/or the C1-C4 diester thereof with one or more polyalkylene glycol having a polymeric structure comprising alkylene oxide units having 2-10 carbon atoms; and

• the weight ratio of soft block (II) to soft block (III)≥ 8.0 and < 12.0; • the weight of the fraction of soft block (III)≥ 0.5 and < 6.0 % by weight with regard to the total weight of the polyether ester block copolymer; and

• the weight of the fraction of soft block (II)≥ 10.0 and < 50.0 % by weight with regard to the total weight of the polyether ester block copolymer; wherein the hard block moieties (I) are moieties formed by reacting one or more aromatic dicarboxylic acid comprising 6-12 carbon atoms and/or the C1-C4 diester thereof with one or more aliphatic diol comprising 2-10 carbon atoms;

wherein the soft block moieties (II) are moieties formed by reacting one or more aromatic dicarboxylic acid comprising 6-12 carbon atoms and/or the C1-C4 diester thereof with one or more polyalkylene glycol having a polymeric structure comprising alkylene oxide units having 2- 10 carbon atoms; and

wherein the soft block moieties (III) are moieties formed by reacting one or more aromatic dicarboxylic acid comprising 6-12 carbon atoms and/or the C1-C4 diester thereof with one or more hydroxy-terminated polysiloxane or a copolymer thereof.

In yet another embodiment, the invention relates to a polyether ester block copolymer comprising:

(I) moieties formed by reacting one or more aromatic dicarboxylic acid comprising 6-12 carbon atoms and/or the C1-C4 diester thereof with one or more aliphatic diol comprising 2-10 carbon atoms;

(II) moieties formed by reacting one or more aromatic dicarboxylic acid comprising 6-12 carbon atoms and/or the C1-C4 diester thereof with one or more polyalkylene glycol having a polymeric structure comprising alkylene oxide units having 2-10 carbon atoms; and

(lll) moieties formed by reacting one or more aromatic dicarboxylic acid comprising

6-12 carbon atoms and/or the C1-C4 diester thereof with one or more hydroxy- terminated polysiloxane or a copolymer thereof;

wherein

• the weight ratio of moieties (II) to moieties (III)≥ 8.0 and < 12.0;

· the weight of the fraction of moieties (III)≥ 0.5 and < 6.0 % by weight with regard to the total weight of the polyether ester block copolymer; and

• the weight of the fraction of moieties (II)≥ 10.0 and < 50.0 % by weight with regard to the total weight of the polyether ester block copolymer. For example, moieties (I) may be moieties formed by reacting dimethyl terephthalate or terephthalic acid with 1 ,4-butanediol and/or ethylene glycol. For example, moieties (I) may be moieties formed by reacting dimethyl terephthalate or terephthalic acid with 1 ,4-butanediol. Alternatively, moieties may be formed by reacting dimethyl terephthalate or terephthalic acid with 1 ,4-butanediol and ethylene glycol.

For example, moieties (II) may be moieties formed by reacting dimethyl terephthalate or terephthalic acid with poly(ethylene glycol) or poly(tetramethylene ether glycol). Preferably, moieties (II) are moieties formed by reacting dimethyl terephthalate or terephthalic acid with poly(tetramethylene ether glycol).

For example, moieties (III) may be moieties formed by reacting dimethyl terephthalate or terephthalic acid with one or more hydroxy-terminated polysiloxane.

More preferably, moieties (I) are moieties formed by reacting dimethyl terephthalate or terephthalic acid with 1 ,4-butanediol; moieties (II) are moieties formed by reacting dimethyl terephthalate or terephthalic acid with poly(tetramethylene ether glycol); and moieties (III) are moieties formed by reacting dimethyl terephthalate or terephthalic acid with one or more hydroxy-terminated polysiloxane.

In a particularly desired embodiment, the invention relates to a polyether ester block copolymer comprising:

(I) moieties formed by reacting dimethyl terephthalate or terephthalic acid with 1 ,4-butanediol and/or ethylene glycol;

(II) moieties formed by reacting dimethyl terephthalate or terephthalic acid with poly(tetramethylene ether glycol); and

(lll) moieties formed by reacting dimethyl terephthalate or terephthalic acid with one or more hydroxy-terminated polysiloxane;

wherein

• the weight ratio of moieties (II) to moieties (III)≥ 8.0 and < 12.0;

• the weight of the fraction of moieties (III)≥ 1.0 and < 5.0 % by weight with regard to the total weight of the polyether ester block copolymer; and

• the weight of the fraction of moieties (II)≥ 10.0 and < 25.0 % by weight with regard to the total weight of the polyether ester block copolymer. In a further particularly desired embodiment, the invention relates to a polyether ester block copolymer comprising:

(I) moieties formed by reacting dimethyl terephthalate or terephthalic acid with 1 ,4-butanediol and ethylene glycol;

(III) moieties formed by reacting dimethyl terephthalate or terephthalic acid with one or more hydroxy-terminated polysiloxane;

wherein

• the weight ratio of moieties (II) to moieties (III)≥ 8.0 and < 12.0;

• the weight of the fraction of moieties (II)≥ 10.0 and < 25.0 % by weight with regard to the total weight of the polyether ester block copolymer.

The invention will now be illustrated by the following non-limiting examples. Preparation of polyether ester block copolymers

Experiment I

A reaction mixture comprising:

• 19.4 g dimethyl terephthalate as dicarboxylic acid diester;

· 9.1 g 1 ,2-ethanediol as alkane diol;

• 4.9 g polytetramethylene ether glycol having M_n of 2000 as polyether glycol; and

• 0.7 g dihydroxy terminated polydimethylsiloxane Baysilone OF-OH 702E,

obtained from Momentive Performance Materials of India, as polysiloxane.

was charged into a dried reactor under nitrogen atmosphere. The reaction mixture was heated from room temperature (23°C) to 160 °C under stirring at 100 rpm during 30 minutes. Subsequently, an amount of 0.15 weight % of titanium (IV) tetraisopropoxide (CAS Reg. Nr. 546-68-9) with regard to the weight of dimethyl terephthalate in the reaction mixture was added as catalyst. The reaction temperature was then increased to 220 °C over a period of 2.0 hours. The reaction mixture was then kept at 220 °C for 60 minutes. During this step, the dimethyl terephthalate was transesterified with the 1 ,2-ethanediol, polytetramethylene ether glycol and dihydroxy terminated polydimethylsiloxane. During the reaction, a quantity of methanol was produced which was distilled out from the reaction mixture under nitrogen atmosphere.

In the second step, polycondensation was performed in the same reactor. The reactor pressure was reduced from atmospheric pressure to 100 mbar and the temperature further increased to 230 °C during 1.0 hour. Then the reactor pressure was further reduced to below 0.1 mbar, the reaction temperature was increased to 250 °C and the stirrer speed reduced to 50 rpm. The reaction mixture was kept under at 250 °C under reduced pressure at <0.1 mbar for a predetermined until no further increase in stirrer torque could be observed. Finally the resulting polyether ester block copolymer was forced from the reactor by applying nitrogen pressure. A polyether ester block copolymer I comprising 78.0 wt% of poly(ethylene terephthalate)-based hard blocks, 20.0 wt% of polytetramethylene ether glycol-based soft blocks and 2.0 wt% polydimethylsiloxane-based soft blocks with regard to the total weight of the polyether ester block copolymer was obtained.

Experiment II

A polyether ester block copolymer was produced via the process of Experiment I except that the reaction mixture comprised:

• 19.4 g dimethyl terephthalate as dicarboxylic acid diester;

• 13.1 g 1 ,4-butanediol as alkane diol;

• 5.5 g polytetramethylene ether glycol having M_n of 2000 as polyether glycol; and

• 0.8 g dihydroxy terminated polydimethylsiloxane Baysilone OF-OH 702E as polysiloxane.

A polyether ester block copolymer II comprising 78.0 wt% of poly(butylene

terephthalate )-based hard blocks, 20.0 wt% of polytetramethylene ether glycol-based soft blocks and 2.0 wt% polydimethylsiloxane-based soft blocks with regard to the total weight of the polyether ester block copolymer was obtained.

Experiment III

• 19.4 g dimethyl terephthalate as dicarboxylic acid diester;

• a mixture of 8.7 g 1 ,4-butanediol and 3.1 g 1 ,2-ethanediol as alkane diol; • 5.6 g polytetramethylene ether glycol having M_n of 2000 as polyether glycol; and

A polyether ester block copolymer III comprising 78.0 wt% of poly(butylene

terephthalate)-poly(ethylene terephthalate)-based hard blocks, 20.0 wt% of polytetramethylene ether glycol-based soft blocks and 2.0 wt% polydimethylsiloxane-based soft blocks with regard to the total weight of the polyether ester block copolymer was obtained. The poly(butylene terephthalate)-poly(ethylene terephthalate)-based hard blocks comprised 16.6 wt% of poly(ethylene terephthalate) repeating units with regard to the total weight of the hard blocks.

Experiment IV

• 19.4 g dimethyl terephthalate as dicarboxylic acid diester;

· 12.7 g 1 ,4-butanediol as alkane diol;

• 5.5 g polytetramethylene ether glycol having M_n of 1000 as polyether glycol; and

A polyether ester block copolymer IV comprising 78.0 wt% of poly(butylene

terephthalate)-based hard blocks, 20.0 wt% of polytetramethylene ether glycol-based soft blocks and 2.0 wt% polydimethylsiloxane-based soft blocks with regard to the total weight of the polyether ester block copolymer was obtained.

Experiment V

• 19.4 g dimethyl terephthalate as dicarboxylic acid diester;

• a mixture of 8.5 g 1 ,4-butanediol and 3.1 g 1 ,2-ethanediol as alkane diol;

• 5.5 g polytetramethylene ether glycol having M_n of 1000 as polyether glycol; and · 0.8 g dihydroxy terminated polydimethylsiloxane Baysilone OF-OH 702E as polysiloxane.

A polyether ester block copolymer V comprising 78.0 wt% of poly(butylene

terephthalate )-poly(ethylene terephthalate)-based hard blocks, 20.0 wt% of polytetramethylene ether glycol-based soft blocks and 2.0 wt% polydimethylsiloxane-based soft blocks with regard to the total weight of the polyether ester block copolymer was obtained. The poly(butylene terephthalate )-poly(ethylene terephthalate)-based hard blocks comprised 16.6 wt% of poly(ethylene terephthalate) repeating units with regard to the total weight of the hard blocks. Experiment VI (comparative)

• 19.4 g dimethyl terephthalate as dicarboxylic acid diester;

• 13.0 g 1 ,4-butanediol as alkane diol; and

· 7.2 g polytetramethylene ether glycol having M_n of 1000 as polyether glycol.

A polyether ester block copolymer VI comprising 75.0 wt% of poly(butylene

terephthalate )-based hard blocks and 25.0 wt% of polytetramethylene ether glycol-based soft blocks with regard to the total weight of the polyether ester block copolymer was obtained. Experiment VII (comparative)

• 19.4 g dimethyl terephthalate as dicarboxylic acid diester;

• 13.0 g 1 ,4-butanediol as alkane diol; and

· 7.2 g polytetramethylene ether glycol having M_n of 2000 as polyether glycol

A polyether ester block copolymer VII comprising 75.0 wt% of poly(butylene

terephthalate )-based hard blocks and 25.0 wt% of polytetramethylene ether glycol-based soft blocks with regard to the total weight of the polyether ester block copolymer was obtained. Experiment VIII

• 19.4 g dimethyl terephthalate as dicarboxylic acid diester;

• 12.7 g 1 ,4-butanediol as alkane diol;

· 9.9 g polytetramethylene ether glycol having M_n of 2000 as polyether glycol; and

• 2.5 g dihydroxy terminated polydimethylsiloxane Baysilone OF-OH 702E as polysiloxane.

A polyether ester block copolymer VIII comprising 65.0 wt% of poly(butylene

terephthalate )-based hard blocks, 30.0 wt% of polytetramethylene ether glycol-based soft blocks and 5.0 wt% polydimethylsiloxane-based soft blocks with regard to the total weight of the polyether ester block copolymer was obtained.

Determination of properties of polyether ester block copolymers

Surface hydrophobicity of polyether ester block copolymers was determined by measuring the contact angle according to ASTM C813-90 (2014) on samples that were conditioned at 50% relative humidity at 23°C for 48 hrs prior to testing. ASTM C813-90 (2014) relates to a standard test method for hydrophobic contamination on glass by contact angle measurement. Samples of 62 mm x 13 mm x 3 mm were prepared via injection moulding.

The contact angle was determined for samples of each polyether ester block copolymer listed in table III. The contact angle reflects the hydrophobicity of the polyether ester block copolymer.

Further samples of each of these block copolymers that also had undergone a conditioning as mentioned were subjected to a boiling treatment by submerging the samples in boiling water under atmospheric pressure for 24 hrs. After the boiling treatment, the samples were again conditioned at 50% relative humidity at 23°C for 48 hrs prior to testing.

Subsequently, the contact angle for each of these samples was determined. The values for the contact angle of the tested samples are presented in table I. The value for contact angle after boiling treatment reflects the resistance to hydrolysis of the polyether ester block copolymer.

Table I

From the values presented in table I, it can be derived that the presence of a

polysiloxane soft block according to the invention results in an improved surface hydrophobicity. Furthermore, it may be derived that use of a mixture of 1 ,4-butanediol and 1 ,2-ethanediol as alkane diol results in an improved surface hydrophobicity.

It can also be derived that the addition of polysiloxane according to the invention results in an improved resistance to hydrolysis. Furthermore, it may be derived that use of a mixture of mixture of 1 ,4-butanediol and 1 ,2-ethanediol as alkane diol results in an improved resistance to hydrolysis.

Tensile properties of polyether ester block copolymers I through VIII were determined in accordance with ASTM D638-10 on type V specimens using a Zwick/Roell Z010 universal tensile testing machine. ASTM D638-10 relates to a standard test method for tensile properties of plastics. Determination of properties was performed at room temperature using samples of 2 mm thickness and a head speed of 50 mm/min. Samples were conditioned at 50% relative humidity at 23°C for 48 hrs prior to testing.

The values for the properties of the tested samples are presented in table II.

Table II

From the values presented in table II, it can be derived that presence of a polysiloxane soft block according to the invention in a weight fraction of≥ 0.5 and < 4.0 weight % with regard to the total weight of the polyether ester block copolymer leads to a desired elongation at break of≥ 300%. Also, it can be derived that presence of a polysiloxane soft block in such quantities that the weight ratio of polyether soft block to polysiloxane soft block according to the invention of≥ 8.0 and < 12.0 leads to a desired elongation at break of≥ 300%.

Thermal properties of polyether ester block copolymers I through VI II were determined in accordance with ASTM D3418-12 using a NETZSCH DSC 200PC differential scanning calorimeter and in accordance with ASTM E1 131 -08 (2014) using a TGA Q 5000

thermogravimetric analyser of TA Instruments. ASTM D3418-12 relates to a standard test method for transition temperatures and enthalpies of fusion and crystallisation of polymers by differential scanning calorimetry. ASTM E1 131 -08 (2014) relates to a standard test method for compositional analysis by thermogravimetry.

Molecular properties of polyether ester block copolymers I through VIII were determined in accordance with ASTM D5296-1 1 using a Shimadzu Class VP LC10 AD. ASTM D5296-1 1 relates to a standard test method for molecular weight averages and molecular weight distribution of polystyrene by high performance size-exclusion chromatography. In the present invention, this standard has been used for determination of the molecular weight of the polyether ester block copolymers.

The values for the properties of the tested samples are presented in table III.

Table III

Mw is the weight average molecular weight as determined according to ASTM D5296-1 1 Tc is the crystallisation peak temperature as determined according to ASTM D3418-12 Tm is the melting peak temperature as determined according to ASTM D3418-12

Tonset is the onset degradation temperature as determined according to ASTM E1 131 -08 (2014). The onset degradation temperature indicates the temperature at which the thermal degradation of the polymeric material starts.

Tpeak is the peak degradation temperature as determined according to ASTM E1 131-08 (2014). The peak degradation temperature indicates the temperature at which the rate of thermal degradation reaches its maximum.

From the values presented in table III, it can be derived that the use of a mixture of two different aliphatic diols in the preparation of polyether ester block copolymers according to the invention results in a reduction of crystallisation temperature. It can furthermore be observed that the polyether ester block copolymers comprising polysiloxane soft blocks have an increased degradation onset and peak temperature.

The above presented examples show that polyether ester block copolymers according to the invention provide improved hydrophobicity and resistance to hydrolysis whilst providing a good balance of mechanical properties and thermal properties.

Claims

1 . Polyether ester block copolymer comprising:

• the weight ratio of soft block (II) to soft block (III)≥ 8.0 and < 12.0;

• the weight of the fraction of soft block (III)≥ 0.5 and < 6.0 % by weight with regard to the total weight of the polyether ester block copolymer; and

2. Polyether ester block copolymer according to claim 1 comprising:

(I) ≥ 49.5 and < 89.5 % by weight with regard to the total weight of the polyether ester block copolymer of hard block moieties formed by reacting one or more aromatic dicarboxylic acid comprising 6-12 carbon atoms and/or the C1-C4 diester thereof with one or more aliphatic diol comprising 2-10 carbon atoms;

(II)≥ 10.0 and < 50.0 % by weight with regard to the total weight of the polyether ester block copolymer of soft block moieties formed by reacting one or more aromatic dicarboxylic acid comprising 6-12 carbon atoms and/or the C1-C4 diester thereof with one or more polyalkylene glycol having a polymeric structure comprising alkylene oxide units having 2-10 carbon atoms; and

3. Polyether ester block copolymer according to any one of claims 1-2 wherein the

weight of the fraction of soft block (III)≥ 0.5 and < 4.0 weight % with regard to the total weight of the polyether ester block copolymer.

4. Polyether ester block copolymer according to any one of claims 1-3 wherein:

• the one or more aromatic dicarboxylic acid comprising 6-12 carbon atoms and/or the C1-C4 diester thereof is one or more selected from terephthalic acid, isophthalic acid, 1 ,4-naphthalenedicarboxylic acid, 1 ,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, dimethyl terephthalate, dimethyl isophthalate, or combinations thereof; and/or

• the one or more aliphatic diol is one or more selected from 1 ,2-ethanediol, 1 ,2- propanediol, 1 ,3-propanediol, 1 ,2-butanediol, 1 ,3-butanediol, 1 ,4-butanediol or combinations thereof; and/or

• the one or more polyalkylene glycol is one or more selected from

• the one or more hydroxy-terminated polysiloxane is an hydroxy-terminated polydimethylsiloxane or a copolymer thereof.

5. Polyether ester block copolymer according to any one of claims 1-4 wherein the

polyalkylene glycol has a number average molecular weight M_n as determined according to ASTM D5296-1 1 of≥ 500 and < 2500 g/mol.

6. Polyether ester block copolymer according to any one of claims 1 -5 wherein the

polysiloxane has an average number of repeating polymeric units of≥ 5 and < 30.

7. Polyether ester block copolymer according to any one of claims 1-6 wherein the

polyether ester block copolymer is obtained by reacting a mixture of reactants comprising a first and a second aliphatic diol each having a different molecular composition.

8. Polyether ester block copolymer according to claim 7 wherein the first and the second aliphatic diol are each selected from 1 ,2-ethanediol, 1 ,2-propanediol, 1 ,3-propanediol, 1 ,2-butanediol, 1 ,3-butanediol and 1 ,4-butanediol.

9. Polyether ester block copolymer according to any one of claims 7 or 8 wherein the first aliphatic diol is 1 ,2-ethanediol and the second aliphatic diol is 1 ,4-butanediol.

10. Polyether ester block copolymer according to any one of claims 7-9 wherein the

quantity of the first and the second aliphatic diol is such as to result in a polyether ester block copolymer in which the ratio of the weight of the fraction of the hard blocks derived from the first aliphatic diol to the weight of the fraction of hard blocks derived from the second aliphatic diol is≥ 0.2 and < 2.0.

1 1. Process for the production of polyether ester block copolymer according to any one of claims 1 -10 by reacting in a polycondensation process comprising two reaction steps a mixture of reactants comprising:

• one or more aromatic dicarboxylic acid selected from terephthalic acid,

• one or more polyalkylene glycol selected from polyethyleneglycol,

polypropyleneglycol, polytetramethyleneetherglycol, or combinations thereof; and

12. Process according to claim 1 1 wherein the mixture of reactants comprises: • 10-40% by weight of a first aliphatic diol selected from 1 ,2-ethanediol, 1 ,2- propanediol, 1 ,3-propanediol, 1 ,2-butanediol, 1 ,3-butanediol, 1 ,4-butanediol; and

wherein the second aliphatic diol has a higher molecular weight than the first aliphatic diol.

13. Process according to claim 12 wherein the weight ratio of the first aliphatic diol to the second aliphatic diol≥ 0.5 and < 1 .5.

14. Process according to any one of claims 1 1 -13 wherein the reaction takes place in the presence of 0.10 - 1 .00 % by weight of a catalyst with regard to the total weight of the one or more aromatic dicarboxylic acid comprising 6-12 carbon atoms and/or the Ci- C₄ diester thereof.

15. Article comprising a polyether ester block copolymer according to any one of claims 1 - 10 or obtained via the process according to any one of claims 1 1 -14.