System for transporting ultra-pure water

Abstract

The present invention relates to use of a PEEK polymer to manufacture articles for transporting ultra-pure water comprising at least one surface intended to be in contact with ultra-pure water, wherein the PEEK polymer is characterised by a total amount of extractables of no more than 3000 µg / g and by an amount of Oligomer (1) of no more than 70 µg / g. The invention further relates to articles comprising at least one surface intended to be in contact with ultra-pure water comprising the PEEK polymer as well as systems for use in transport of ultra-pure water.

Description

DescriptionSystem for transporting ultra-pure waterReference To Related ApplicationsThis application claims priority from US provisional application Nr. 63 / 550400 filed on February 6, 2024, the whole content of which being incorporated herein by reference for all purposes.Technical Field

[0001] The present invention relates to systems and articles for the transport of ultra-pure water.Background Art

[0002] Ultra-pure water is employed in many steps of semiconductors manufacturing process. Water is used for washing and rinsing of semiconductor components during manufacture. Water is also used for cleaning and etching operations, making steam for oxidation of silicon surfaces, preparing photomasks and depositing luminescent materials. Water of a higher quality is needed as the integration of semiconductors advances further.

[0003] Other high-tech applications requesting ultra-pure water are in the development and fabrication of solid-state devices, thin-film devices, communication lasers, light-emitting diodes, photo-detectors, printed circuits, memory devices, vacuum-tube devices, or electrolytic devices.

[0004] As defined in ASTM D5127-07, ultra-pure water is required to prevent contamination of products during manufacture, since contamination can lead to an unacceptable, low yield of electronic devices. Ultra-pure water thus needs to present very low levels of inorganic cations and anions, of organic contamination and of biological contamination.

[0005] The preparation of ultra-pure water involves the removal of ions, organic and biological contaminants and particulates. Ultra-pure water typically exhibits an electric resistivity at 25°C of 18.1 MO. cm or higher and a Total Organic Carbon level (TOC) of maximum 10.0 pg / L. Bacterial contamination can also be limited to no more than 10.0 CFU / mL (CFU: colony forming unit).

[0006] Polyvinylidene fluoride (PVDF) is widely used for the manufacture of pipe systems (including pipes, connectors, and other parts) used in the transport of ultra-pure water for use in the semiconductor industry.

[0007] With the development of smaller chips, the level of purity required for ultra- pure water is such that PVDF is no longer adapted in the entire transport system, mainly due to the leaching of organic impurities and fluoride anions in places where higher temperatures are used (80-120°C).

[0008] Polyetheretherketone (PEEK) has been described as particularly well adapted for replacing PVDF in the transportation of ultra-pure water at higher temperature (80-120°C typically) as it presents a reduced level of leaching as compared to PVDF.

[0009] The use of PEEK polymers for the manufacture of piping used in the treatment of ultra-pure water is known in the art, for example from US 4,784,772 (in the name of Mitsui Toatsu Chemical Incorporated).

[0010] However, because of its high melting temperature (340-345°C) the processing of PEEK requires a very high temperature (above 360°C). Under these high temperature conditions, in extrusion long running times, some low molecular weight compounds can be vaporized off the polymer and form a deposit on the extruder die. This deposit is usually solid and creates defects on the extruded article as the deposit gets loose. The deposit is generally referred to as “die lip build-up”. The vapours released by the extruder can also be a problem in some applications requiring high purity environment (clean rooms). These phenomena may sometimes be referred to as “off-gassing”.

[0011] The low molecular weight compounds present in these deposits are mostly residual diphenyl sulfone solvent, residual 4,4’-difluorobenzophenone monomer and oligomers. The oligomers are difficult to remove by standard extraction processes using solvents of limited solvent power (acetone, ethanol). This makes it difficult to implement an industrially viable process for reducing the presence of the oligomers at the end of the polymerization process. Hence limiting their formation during the polymerization reaction allows for the production of PEEK with limited level of low molecular weight compounds associated with off-gassing and die lip build-up.

[0012] These low molecular weight compounds can be quantified by Soxhlet extraction with acetone and It has now been found that it is possible to manufacture PEEK polymers having a total amount of extractables of no more than 3000 pg / g and which contain no more than 70 pg / g of Oligomer 1 as defined hereafter. The use of such PEEK polymers in the manufacture of articles by melt processing allows for a significant reduction in organic compounds associated with off-gassing and die lip build-up making the resulting articles suitable for transporting ultra-pure water.Summary of invention

[0013] Facing the problem of providing a polymer for the manufacture of a system suitable for transporting ultra-pure water, the Applicant surprisingly found that the use of a PEEK polymer powder characterised by a total amount of extractables of no more than 3000 pg / g of polymer powder and no more than 70 pg / g of Oligomer 1 as defined hereafter allows manufacturing articles by extrusion or injection molding with reduced level of off-gas generation and die lip build-up and hence reduced risk of contamination on the obtained articles.

[0014] The PEEK polymer in the form of pellets is advantageously characterised by a total amount of extractables of no more than 3000 pg / g, preferably no more than 2000 pg / g, and an amount of Oligomer 1 of no more than 70 pg / g-

[0015] The PEEK polymer is also advantageously characterised by a crystallization temperature, Tc, measured using differential scanning calorimetry (DSC) as detailed in the examples, of at least 278°C.

[0016] Articles obtained from the PEEK polymer are also characterised by an amount of extractable of no more than 3000 pg / g, preferably no more than 2000 pg / g, and an amount of Oligomer 1 of no more than 70 pg / g.

[0017] The invention further provides for methods for the preparation of a PEEK polymer characterised by a total amount of extractables of no more than 3000 pg / g and an amount of Oligomer 1 of no more than 70 pg / g.Description of the invention

[0018] Definitions

[0010] For the purposes of the present description:- the use of parentheses before and after symbols or numbers identifying compounds, chemical formulae or parts of formulae has the mere purpose of better distinguishing those symbols or numbers from the rest of the text and hence said parentheses can also be omitted;- the expression “comprising a” should be understood as meaning “comprising at least one”. The expression “a” or “an” should be understood as meaning “at least one”;- the expression such as “Object P comprises at least the elements p1 , p2... pi” should also be understood as encompassing explicitly the embodiment wherein Object P consists essentially of the elements p1 , p2 ... pi;-“essentially” in this context means that some impurities, undesired species, unintentional compounds or the like could be present in Object P without impacting its targeted function and effect in the framework of the present invention;-the expression “comprised between ... and ...” or “ranging from... to...” and the like should be understood as including the limits;- “crystallization temperature (Tc)” or “melting temperature (Tm)” are intended to indicate the crystallization temperature or the melting temperature measured by differential scanning calorimetry (DSC) according to ASTM D3418 at 20°C / min cooling rate;- “ultra-pure water” denotes a water exhibiting an electric resistivity at 25°C of at least 18.0 MO. cm and a Total Organic Carbon (TOC) of at most 10.0 pg / L. Both properties are generally measured by standard tools. TOC is preferably measured according to ASTM D5997 - 15. The UPW may more particularly be any water conforming with any of the recommendations of Table 1 of ASTM D5127 - 13 (Reapproved 2018). The UPW may more particularly be any of the 4 following types of water as defined in Table 4 of ASTM D5127-13 (Reapproved 2018): type E-1 , type E-1.1 , type E-1.2 or type E-1 .3. To be noted: ASTM Type E-1 .3 is also identical to the SEMI (Semiconductor Equipment and Materials International) Guide for Ultrapure Water Used in Semiconductor Processing (F063), 2010 version.

[0019] A first object of the present invention is the use of a PEEK polymer powder, hereinafter referred to as “PEEK Polymer Powder”, to manufacture articles for transporting ultra-pure water comprising at least one surface intended to be in contact with ultra-pure water, wherein thePEEK Polymer Powder is characterised by a total amount of extractables of no more than 3000 pg / g and by an amount of Oligomer 1 of no more than 70 pg / g[Oligomer 1 ], and wherein the amount of extractables and of Oligomer 1 are determined by Soxhlet extraction with acetone for 48 hours followed by liquid chromatography.

[0020] The PEEK Polymer Powder is characterised by a total amount of extractables of no more than 3000 pg / g and by an amount of Oligomer 1 of no more than 70 pg / g. The expression “pg / g” when referred to the amount of extractables and of Oligomer 1 is relative to the amount in grams of the PEEK polymer.

[0021] For the avoidance of doubts, the total amount of extractables includes Oligomer 1 .

[0022] The total amount of extractables is determined by subjecting a sample of the PEEK Polymer Powder which has been processed to have a median particle size dso in the range of 200 to 300 microns to a Soxhlet extraction process in acetone for 48 hours. At the end of the 48 hours, the extract is concentrated and dried to constant weight at room temperature under vacuum. The weight of the extract represents the total weight of extractables / g polymer.

[0023] The particle size of the PEEK polymer powder to be used for the determination of the amount of extractables is determined by laser scattering from a dispersion of the particles in 2-propanol. The expression “median particle size” or the notation “dso” have the usual meaning used in the field of particle size distributions. For the sake of clarity, dncorresponds to the diameter of the particles for which n% of the particleson a volume basis have a diameter which is less than dn. Hence, dso (median) is defined as the size value corresponding to the cumulative distribution at 50%, the distribution being a volume distribution.

[0024] The amount of Oligomer 1 in the extract can be determined using known chromatographic techniques. The retention times of the main components in the extract can be identified by LC-MS or by preparing actual standards. Oligomer 1 can be prepared according to Fukawa et al, Journal of Polymer Science : Part A : Polymer Chemistry, 1993, Vol. 31 , P 535-546 and used to determine the retention time under the testing conditions used for the analysis of the extract.

[0025] A detailed protocol for the determination of the total amount of extractables and of Oligomer 1 is detailed in the Experimental Section under the heading “Extractables Determination”.

[0026] The expression “PEEK Polymer” is used herein to refer to a polyaryletherether ketone polymer which comprises at least 80 mol%, preferably at least 85 mol%, preferably at least 90 mol%, more preferably at least 95 mol%, even more preferably at least 98 mol%, at least 99 mol% and even 100 mol% of recurring units of formula (RPEEK):

[0027] Preferably, when the PEEK Polymer comprises less than 100 mol% of recurring units of formula (RPEEK) as represented above, it comprises up to 1 mol%, up to 2 mol%, up to 5 mol%, up to 10 mol%, up to 15 mol% or up to 20 mol% of at least one recurring unit selected from the ones having formula (K-A) to (K-P) below:wherein each R’ is independently selected from halogen, an alkyl, an alkenyl, an alkynyl, an aryl, an ether, a thioether, a carboxylic acid, an ester, an amide, an imide, an alkali or an alkaline earth metal sulfonate, an alkyl sulfonate, an alkali or alkaline earth metal phosphonate, an alkyl phosphonate, an amine and a quaternary ammonium; and each j’ is independently 0 or an integer from 1 to 4. Typically, each j’ is 0.

[0028] Advantageously, the PEEK Polymer comprises at least 98 mol%, at least 99 mol% and even more preferably 100 mol% of recurring units of formula (RPEEK).

[0029] The PEEK Polymer is also advantageously characterised by a crystallization temperature, Tc, measured using differential scanning calorimetry (DSC), of at least 278°C. The PEEK Polymer may advantageously have a crystallization temperature, Tc, of at least 279°C, even at least 280°C, preferably at least 281 °C.

[0030] The PEEK Polymer is characterised by a number average molecular weight (Mn) and / or weight average molecular weight (Mw) in a range which allows to compromise between melt strength, ductility and low viscosity for ease of processing.

[0031] Mn and Mw are measured by gel permeation chromatography (GPC) at 160 °C in 1 ,2,4-trichlorobenzene:phenol (50:50) using polystyrene (PS) standards.

[0032] The PEEK Polymer generally has a Mn in the range from 29,000 to 58,000. The PEEK Polymer generally has a Mw in the range from 60,000 to 125,000.

[0033] The PEEK Polymer Powder may be prepared according to a process which comprises: reacting hydroquinone, 4,4’-difluorobenzophenone and optionally other monomers, in a solvent comprising more than 80 wt% diphenyl sulfone, using alkali metal carbonate as base; and- isolating the polymer by extraction with an organic solvent using at least 50 L organic solvent / kg of polymer followed by extraction with water, and in which the molecular weight of the polymer and its end groups are controlled by one of the following methods:- use of low boiling mono-functional end capping agent, such as phenol, 4-phenoxyphenol, 4-fluorobenzophenone, preferably at the start of the reaction; or- use of an excess of 4,4’-difluorobenzophenone of 1.5-2.5 mol% with no end capping; or- use of an excess of 4,4’-difluorobenzophenone in one or more termination step in which the amount of 4,4’-difluorobenzophenone used in all of the termination steps included is less than 5 mol% based on hydroquinone; or- use of a difluorinated ketone with at least 3 aromatic rings, such as 1 ,4-(bis-4’-fluorobenzoyl)benzene or 1 ,3-(bis-4’- fluorobenzoyl)benzene.

[0034] The excess of 4,4’-difluorobenzophenone is calculated based on the moles of hydroquinone or based on the total amount of diol monomers in the reaction when the PEEK Polymer does not consist of 100 mol% of recurring units of formula (RPEEK).

[0035] The reagents used for termination can be added to the reactor as powder or liquid form.

[0036] The PEEK Polymer Powder may alternatively be prepared according to a process which comprises:- reacting hydroquinone, 4,4’-difluorobenzophenone and optionally other monomers, in a solvent comprising more than 80 wt% diphenyl sulfone, using alkali metal carbonate as base, isolating the polymer by extraction with an organic solvent followed by extraction with water to reduce the dipolar aprotic solvent content to less than 100 ppm, in which the organic solvent is a dipolar aprotic solvent with dielectric constant of at least 30.

[0037] Dipolar aprotic solvents with a dielectric constant of at least 30 suitable for the process are dimethylacetamide, dimethylformamide or dimethylsulfoxide.

[0038] The concentration of the PEEK Polymer at the end of the polymerization is preferably below 45% solids, calculated as the ratio between the (wt theroretical polymer) / (theoretical polymer wt + wt solvent) expressed in %. The alkali metal carbonate is preferably sodium and / or potassium carbonate, preferably a mixture of sodium and potassium carbonate.

[0039] In general, the process comprises more than one termination steps. It comprises adding the termination agent in more than one step, typically two or more steps. A process for the preparation of PEEK comprising the addition of the termination agent in more than one step is disclosed for instance in EP2178946B1 , the whole content of which is incorporated herein by reference for all purposes.

[0040] The first termination step is conducted with less than 0.5 mol% of any lithium, or alkaline earth metal salt present in the reaction mixture at that stage, this in order to ensure full reactivity of end groups to be end capped. Without wishing to be bound by any theory, the Applicant believes that this ensures a good crystallization rate of the PEEK Polymer, that is a high crystallization temperature. The time between the addition of the first termination agent and lithium, or alkaline earth metal salt is at least 3 minutes to ensure efficient end capping before adding a reagent (lithium or alkaline earth salt) which reduces the reactivity of the end groups.

[0041] The PEEK Polymer Powder is used to manufacture articles which are suitable for the transport of ultra-pure water and which comprise a surface intended to be in contact with ultra-pure water. In particular, the PEEK Polymer Powder is used to manufacture the surface of the article intended to be in contact with ultra-pure water.

[0042] The articles are generally manufactured by melt processing, preferably by extrusion or injection molding.

[0043] A further object of the invention is therefore a process for the manufacture of articles for transporting ultra-pure water comprising at least one surface intended to be in contact with ultra-pure water, the process comprising a step of melt processing the PEEK Polymer Powder.

[0044] The process may comprise one step in which the PEEK Polymer Powder is melt processed into the article, in particular the surface of the article intended to be in contact with ultra-pure water.

[0045] Alternatively, the process may comprise a first step in which the PEEK Polymer Powder is extruded into pellets which are then further processed into the article. The process accordingly comprises the steps of:(a) providing the PEEK Polymer Powder as defined above;(b) melting processing said PEEK Polymer Powder to provide PEEK Polymer pellets; and(c) forming said PEEK Polymer pellets into at least one article for transporting ultra-pure water.

[0046] In step (c) PEEK Polymer pellets are melt processed into the surface of the article intended to be in contact with ultra-pure water.

[0047] Preferably, step (c) can be performed by methods such as extrusion or injection moulding. The method can be properly selected based on the article to be formed using techniques well known to the person skilled in the art of thermoplastic polymer processing.

[0048] When the article is manufactured using an extrusion process the PEEK Polymer is typically selected from polymer having a Mn higher than 42,000, preferably higher than 43,000, more preferably higher than 44,000, and a Mn lower than 58,000, preferably lower than 57,000, more preferably lower than 56,000. The PEEK Polymer then typically has a Mw higher than 90,000, more preferably higher than 95,000, even more preferably higher than 97,000 and a Mw lower than 125,000, more preferably lower than 120,000, even more preferably lower than 115,000, and still more preferably lower than 110,000.

[0049] When the article is manufactured by injection moulding, the PEEK Polymer advantageously has a Mn higher than 29,000, preferably higher than 30,000, preferably higher than 31 ,000 and a Mn lower than 54,000, more preferably lower than 53,000, even more preferably lower than 52,000. The PEEK Polymer advantageously has a Mw higher than 60,000, preferably higher than 62,000, more preferably higher than 63,000 and a Mw lower than 110,000, more preferably lower than 108,000, even more preferably lower than 107,000.

[0050] Without being bound by any theory, the selection of the above mentioned ranges of Mn and Mw allows for good melt strength and high ductility, which are both critical in this application, while minimising viscosity for ease of processing.

[0051] In an embodiment of the process a lubricant is added to the PEEK Polymer pellets before they are formed into the article.

[0052] Accordingly, the process further comprises a step of adding a lubricant to the PEEK Polymer pellets either before or during step (c).

[0053] The lubricant may be any the lubricant commonly used in the processing of PEEK polymers. Preferably, the lubricant is a low melting hydrocarbon- based lubricant, more preferably a hydrocarbon-based lubricant having a melting point below 250 °C, even more preferably below 200 °C.

[0054] Preferably, said lubricant is based on a saturated hydrocarbon. More preferably the lubricant is selected from fatty acid salts, even more preferably from salts of saturated fatty acids with 10-20 carbon atoms.

[0055] Preferably, said lubricant is selected from calcium stearate, calcium palmitate, magnesium stearate, magnesium palmitate, zinc stearate or zinc palmitate. More preferably, the lubricant is selected from calcium stearate, calcium palmitate, zinc stearate or zinc palmitate; even more preferably from calcium stearate or calcium palmitate. The most preferred is calcium stearate.

[0056] The amount of lubricant is such that the residual amount of cations deriving from the lubricant, Ca, Mg or Zn, is in the range from 6 to 18 ppm, preferably 7 to 18 ppm as measured in the PEEK Polymer in the article by ICP-OES (inductively coupled plasma coupled with optical emission spectroscopy) after mineralization by ashing in a platinum crucible.

[0057] In an alternative embodiment of the process no lubricant is added to the PEEK Polymer pellets before they are formed into the article. In such an embodiment, the amount of cations of Ca, Mg or Zn in the PEEK Polymer in the article is advantageously no more than 5 ppm, as measured by ICP- OES (inductively coupled plasma coupled with optical emission spectroscopy) after mineralization by ashing in a platinum crucible.

[0058] Advantageously the amount of cations of Ca, Mg or Zn in the PEEK Polymer in the article is less than 4 ppm, even as low as 1 ppm or even as low as 0.5 ppm.

[0059] In this embodiment, melt processing is preferably performed using so- called barrier screws. The expression “barrier screw” is used herein to refer to a screw which comprises a secondary flight starting at the beginning of the screw transition zone and ending at the start of the final metering zone, so that the channel of the screw is divided into two and the melted polymer is separated from the unmolten pellets.

[0060] Melt processing the PEEK Polymer Powder may lead to a reduction of the amount of total extractables due to a certain level of volatilization that takes place during the processing. Accordingly the total amount of extractables in the melt processed pellets of the PEEK Polymer or in the article may be lower than in the powder.

[0061] A further object of the present invention is an article for transporting ultra- pure water comprising a surface intended to be in contact with ultra-pure water comprising a PEEK Polymer, said surface being characterised by a total amount of extractables of no more than 3000 pg / g and by an amount of Oligomer 1 of no more than 70 pg / g,the amount of extractables and of Oligomer 1 being determined by Soxhlet extraction with acetone for 48 hours followed by liquid chromatography as detailed in the experimental Section under the heading “Extractables determination”.The total amount of extractables is determined on a sample of the PEEK Polymer which conveniently has a median particle size, dso, in the range of 200 to 300 microns, measured using laser scattering on a dispersion of the particles in 2-propanol. The sample of the PEEK Polymer with the appropriate particle size is obtained from the article by taking an amount of the PEEK Polymer from the article and milling or grinding it to the desired particle size using techniques known to the person skilled in the art.

[0062] The surface of the article intended to be in contact with ultra-pure water comprises, essentially consists of, preferably consists of, the PEEK Polymer.

[0063] Preferably, the surface of the article intended to be in contact with ultra- pure water is characterised by a total amount of extractables of no more than 2500 pg / g, even no more than 2000 pg / g, and by an amount of Oligomer 1 of no more than 70 pg / g.

[0064] The article itself may comprise or consist of the PEEK Polymer.

[0065] Advantageously, the PEEK Polymer in the article has a crystallinity as measured by DSC on the first heat scan of at least 20%, preferably at least 25% with respect to the theoretical crystallinity of PEEK. The level of crystallinity is determined by measuring the heat of fusion on the first heat scan of the PEEK Polymer in the finished article and assuming that 100% crystalline PEEK has a heat of fusion of 130 J / g.

[0066] The article can be selected from pipe(s) and pipe connector(s) (also referred to as “pipe fitting(s)”).

[0067] A pipe connector is a component that can be mechanically attached to one end of a pipe. The pipe connector is intended to either (i) mechanically bond two pipe endings or (ii) mechanically bond one pipe ending to another component of the system.

[0068] The pipe connector may be selected in the group consisting of adapter(s), elbow(s), coupling(s), union(s), reducer(s), tee(s) (also referred to as “T- fitting(s)”), cross(es) (also referred to as “four-way fitting(s)”).

[0069] The Applicant surprisingly found that the use of the PEEK Polymer allows obtaining articles such as pipes and pipe connectors that have a consistent wall thickness even when extruded in the absence of a lubricant.

[0070] As used herein, the expression “consistent wall thickness” is intended to indicate a thickness variation of the wall of the component of less than 20%, more preferably of less than 10%, from the nominal wall thickness, as measured by X-ray at least one point, preferably at least two or more points, of the wall of the component.

[0071] The consistent wall thickness of the article according to the present invention is of particular interest when such a component is a pipe.

[0072] Hence, the pipe according to the present invention has a thickness variation of its wall of less than 20%, preferably of less than 10% from the nominal wall thickness, as measured via X-ray in at least one point, preferably in at least two or more points of the wall of the pipe.

[0073] Also, the pipe connector of the present invention has a thickness variation of its wall of less than 20%, preferably of less than 10% from the nominal wall thickness, as measured via X-ray in at least one point, preferably in at least two or more points of the wall of the pipe connector.

[0074] In an aspect of the present invention the article is a pipe for transporting ultra-pure water having a surface intended to be in contact with ultra-pure water comprising the PEEK Polymer.

[0075] The pipe comprises one or more layers. The internal layer intended to be in contact with ultra-pure water comprises, essentially consists of or preferably consists of the PEEK Polymer.

[0076] According to an embodiment (E1 ), the pipe is a monolayer pipe. In this embodiment, the monolayer consists of the internal layer (L). It comprises only layer (L). The monolayer pipe can be prepared by extrusion.

[0077] According to embodiment (E1 ), layer (L) corresponds to the wall of the pipe and the thickness of layer (L) corresponds to the thickness of the wall of the pipe. Layer (L) has a consistent wall thickness. Preferably, layer (L) has a thickness variation of less than 20%, more preferably of less than 10% from the nominal thickness of layer (L), as measured via X-ray at least one point, preferably at least two or more points of the pipe.

[0078] Layer (L) comprises, essentially consists of, consists of the PEEK Polymer.

[0079] According to another embodiment (E2), the pipe of the invention is a multilayer pipe. In this embodiment, the pipe comprises more than one layer and layer (L) is the internal layer intended to be in contact with ultra- pure water. For instance, the pipe may comprise layer (L) and one outer layer. According to embodiment (E2), as the layer(s) other than layer (L) is / are not intended to be in contact with ultra-pure water, there is less risk of contaminating the water with molecules leached from these layers. As a consequence, layer(s) other than layer (L) may comprise at least one filler and / or at least plastic additive. The multilayer pipe can be prepared bycoextrusion or by overmolding the other layer(s) around layer (L). Preferably, the pipe is prepared by (co)extrusion.

[0080] According to embodiment (E2), layer (L) and the layer(s) other than layer (L) correspond to the wall of the pipe and the thickness of layer (L) plus the thickness of the layer(s) other than layer (L) corresponds to the thickness of the wall of the pipe. Preferably, the multilayer pipe has a thickness variation of its wall of less than 20%, more preferably of less than 10% from the nominal wall thickness, as measured via X-ray on at least one point, preferably at least two or more points of the pipe.

[0081] The layer(s) other than layer (L) may comprise at least one thermoplastic polymer, at least one filler and / or at least plastic additive, notably selected in the group consisting of colorants (for example, dyes and / or pigments), impact modifiers, ultraviolet light stabiliser, heat stabilisers, antioxidants, internal lubricants and / or external lubricants, flame retardants, anti-static agents, anti-blocking agents and combinations thereof.

[0082] More particularly according to embodiment (E2), the pipe of the invention comprises:- an internal layer (or wall) (L) intended to be in contact with ultra-pure water, said layer (L) comprising, essentially consisting of, preferably consisting of the PEEK Polymer;- at least one other layer which is made of or comprises a polymer composition comprising at least one polymer (P) as defined herein and (i) at least one filler and / or (ii) at least one plastic additive, notably selected in the group consisting of colorants (for example, dyes and / or pigments), impact modifiers, ultraviolet light stabiliser, heat stabilisers, antioxidants, internal lubricants and / or external lubricants, flame retardants, anti-static agents, anti-blocking agents and combinations thereof.

[0083] The diameter of the inventive pipe is generally between 1 and 200 mm. The diameter may more particularly be between 20 and 150 mm.

[0084] The length of the pipe is generally at most 100 m. The length may more particularly be at most 50 m.

[0085] The pipe of the invention can be used to transport ultra-pure water since layer (L), intended to be in contact with ultra-pure water, is made from the PEEK Polymer.

[0086] The pipe of the invention contains ultra-pure water and / or is characterised by the amounts of eluted impurities given below.

[0087] In view of the very low amounts of extractables of the PEEK Polymer the article of the invention meets the strict requirements of the semi-conductor industry. SEMI F40 and SEMI F57 are norms edited by association SEMI®, 673 S. Milpitas Blvd., Milpitas, CA95035 (USA), which are often followed to test polymer materials and components used in ultra-pure water systems to assess whether the material can suitably be used without contaminating ultra-pure water. Pursuant to these norms, the following protocol (p1 ) can be used for measuring the amounts of the eluted impurities in the pipe:

[0088] The pipe of the invention is such that following the above mentioned protocol, the amounts of eluted impurities (“IMP” hereinafter) released from layer (L) after bringing layer (L) in contact with ultra-pure water at85°C for 7 days are less than the values indicated in the Table below:

[0089] The amounts of eluted impurities are expressed in pg / m2of the surface of layer (L) in contact with water. The eluted impurities comprise both inorganic and organic species.

[0090] Another aspect of the present invention is a pipe connector comprising a surface intended to be in contact with ultra-pure water, said pipe connector having at least one surface comprising, essentially consisting of or consisting of the PEEK Polymer.

[0091] The pipe connector may advantageously consist of the PEEK Polymer.

[0092] Preferably, the pipe connector is prepared by injection moulding.

[0093] The pipe connector of the invention can be used to transport ultra-pure water since the surface intended to be in contact with water is made from the PEEK Polymer.

[0094] SEMI F40 and SEMI F57 are norms that can be used to characterise the pipe connector. Pursuant to these norms, the following protocol (p2) can be used for measuring the amounts of the eluted impurities:

[0095] The pipe connector of the invention is such that following the above mentioned protocol, the amounts of elution of the impurities (IMP) released from the surface in contact with ultra-pure water are less than the values of eluted impurities expressed in pg / m2of the surface of the leaching area indicated in the Table below:

[0096] A further object of the invention is a system for the storage or transport of ultra-pure water comprising at least one article as defined above.

[0097] The system may comprise pipes and pipe connectors as defined above. It may also comprise other components, such as reservoirs or tanks.Reservoirs, tanks or other components of the system of the invention may also be made of the PEEK Polymer.

[0098] The system may also comprises at least one means for creating a difference of pressure to transport the water, for example a pump.

[0099] In still another aspect, the present invention relates to a method for transporting ultra-pure water, wherein at least one pipe or a pipe connector as defined above is used.

[0100] Should the disclosure of any patents, patent applications, and publications which are incorporated herein by reference conflict with the description of the present application to the extent that it may render a term unclear, the present description shall take precedence.

[0101] The disclosure is now described in more detail with reference to the following examples, whose purpose is merely illustrative and not intended to limit the scope of the disclosure.Experimental Section

[0102] Raw Materials

[0103] Hydroquinone (HQ), photographic grade, was procured from Eastman, USA, containing 0.38 wt% moisture, which amount was used to adapt the charge weights. All weights indicated include moisture.

[0104] 4,4’-Difluorobenzophenone (DFBP), polymer grade (99.8%+), was procured from Malwa, India and was shown to contain oxidising species in a concentration less than 3.0 pmol TiCh / g as measured by redox titration as described in WO2012 / 001131 .

[0105] Diphenyl sulfone (DPS) (polymer grade) was procured from Proviron (99.8% pure).

[0106] Sodium carbonate, light soda ash, was procured from Solvay S.A., France.

[0107] Potassium carbonate with a doo < 45 pm was procured from Armand products.

[0108] Lithium chloride (anhydrous grade) was procured from Acres.

[0109] Determination of Mn and Mw by Gel Permeation Chromatography (GPC)

[0110] Molecular weights of the sample were determined by PL 220 high temperature GPC system using conditions described in Table 1 below. Table 1

[0111] The sample concentration was ~0.20% wt. / vol. in mobile phase. The sample was dissolved by heating at about 190°C under magnetic stirring until complete dissolution. GPC method used was similar to ASTM D5296 but modified due to the need of different solvent, GPC column and conditions. Calibration was carried out using 11 narrow calibration standards of Polystyrene (standards purchased from Agilent Technologies having peak molecular weight range: 1210000 to 580)

[0112] Determination of the melting temperature (Tm ), crystallization temperature (Tc) and heat of fusion

[0113] The heat of fusion was determined on the melting endotherm of the first heat scan in differential scanning calorimeter (DSC) according to ASTM D3418-03, E1356-03, E793-06, E794-06.

[0114] Details of the procedure as used herein are as follows: a TA Instruments DSC Q20 was used with nitrogen as carrier gas (99.998% purity, 50 mL / min). Temperature and heat flow calibrations were done using indium. Sample size was 5 to 7 mg. The weight was recorded ±0.01 mg. The heat cycles were:1st heat cycle: 30.00°C to 400.00°C at 20.00°C / min, isothermal at 400.00°C for 1 min;1st cool cycle: 400.00°C to 30.00°C at 20.00°C / min, isothermal for 1 min; 2nd heat cycle: 30.00°C to 400.00°C at 20.00°C / min, isothermal at 400.00°C for 1 min.

[0115] The melting temperature of the composition was taken as the area over a linear baseline drawn from 220°C to a temperature above the last endotherm. Any exotherm associated with cold crystallisation is taken into account for the total heat of fusion measured on the 1 st heat scan. The % crystallinity is defined as 100 x heat of fusion (J / g) 1 130 (J / g).

[0116] The crystallization temperature Tc was determined as the peak temperature of the crystallization exotherm on the 1stcool cycle.

[0117] Extractables Determination

[0118] The total amount of extractable was quantified by Soxhlet extraction. The analysis was performed on PEEK powder having a median particle size (dso determined by laser scattering in wet mode in 2-propanol) in the range of 200 to 300 pm. Grinding and / or sieving was performed on the sample to adjust the particle size to obtain a median diameter in the 200-300 pm range.

[0119] 8.000 g of PEEK powder were introduced in a cellulose extraction thimble (25 mm internal diameter x 80 mm height) and placed in a 50 mL Soxhlet extractor with cotton wool (rinsed with acetone before use) on top of the powder to avoid powder overflowing. The extractor, with a reflux condenser refrigerated with chilled water (4 °C), was fitted on a 500 mL 3- neck jacketed round bottom flask, along with a thermocouple and a nitrogen inlet line. 250 mL acetone with distillation beads were added and heat was applied via the reactor jacket to reflux the acetone. The reflux rate was adapted to have the Soxhlet extractor fill and empty once every 3 to 5 minutes. After 48h, the heat source was removed and the acetone extract cooled down to room temperature. The extract was concentrated on a Rotavapor and dried to constant weight at room temperature under vacuum.

[0120] The weight of extract represents the total amount of extractables / g polymer.

[0121] The extract was analyzed by HPLC under the following conditions.

[0122] The sample was prepared by dissolution of 15-40 mg in 100 mL dimethylformamide.

[0123] The equipment was an Alliance 2695 Liquid Chromatograph with 2996PDA detector or equivalent and the column was Supelco Discovery C-18, 250mm x 4.6mm; 5mm particle size.

[0124] The mobile phase contained acetonitrile and water according to the following gradient program:Flow Rate: 1.00 mL / minuteRun Time: 30 minutesPDA Detector: 254 nm

[0125] Under these conditions, diphenyl sulfone eluted at 5.7 minutes and 4,4’- difluorobenzophenone at 7.1 minutes. These two compounds could be quantified in the extract and consequently in the polymer using external standards.

[0126] Other species present in the total extractable, mainly oligomers of different structures, were detected at 9.5, 10.4, 12.1 , 13.2, 16.0 and 19.7 minutes.

[0127] The compounds peak retention times can be identified by LC-MS or by preparing actual standards. Oligomer 1 was prepared according to Fukawa et al, Journal of Polymer Science : Part A : Polymer Chemistry, 1993, Vol 31 , P 535-546.

[0128] Using the standard the peak at 10.4 minutes was attributed to Oligomer 1. The concentration of Oligomer 1 was determined using 4,4’- difluorobenzophenone as external standard.

[0129] Determination of surface eluted impurities per SEMI-40

[0130] The sample containers, containing one plaque each, were filled with ultrapure water (milliQ) for 2 minutes. Then the water was drained. This was repeated 10 times. For the actual leaching test the containers were filled an 11th time either with just enough water to cover the plaque. The tests were carried out in triplicate for each plaque type.

[0131] In parallel, 5 ‘blank’ glass containers and 5 ‘blank’ HDPE containers, containing the same amount of ultrapure water but no plaques, were submitted to exactly the same procedure as the bottles containing the plaques. These are the ‘procedure blanks’.

[0132] The containers containing the plaques and the procedure blank containers were then placed in an oven for 7 days at 85 °C. They were agitated once a day, except during the weekend.

[0133] After the 7 days leaching, the sample solutions were transferred into clean recipients for the TOC, metals and anions measurements. The solutions for the metals determination were slightly acidified with cone. HNO3 immediately after the transfer in order to stabilise the metals.

[0134] The surface extractable metals (SEMI F57 list) were measured by high resolution ICP-MS using a Thermo Element 2 instrument.

[0135] The surface extractable anions (SEMI F57 list) were measured by ion chromatography (IC) using a Dionex ICS-5000 instrument.

[0136] The TOC (Total Organic Carbon) was measured as the difference between TC (Total Carbon) and TIC (Total Inorganic Carbon) using a Shimadzu TOC-L instrument.

[0137] Measurement of thickness of tubes

[0138] The thickness of the tubes was measured with a X-rays system using a Zumbach RAYEX S XT110 equipment.

[0139] The tube to be tested was run through the measuring unit where it was X- rayed for a short period in both horizontal and vertical axes using an X-ray beam. An X-ray sensitive detector on the opposite side, for each source, measured the intensity of the incident rays during the exposure time. Since the product absorbs more or less, depending on the thickness of the layer, an absorption curve-of the product was obtained for each axis. From the absorption curves, it was possible to calculate and create a reconstructed image of the diameter, thicknesses, out of roundness and eccentricity. The system had a resolution of 5 micron.

[0140] Determination of Fluorine Concentration in Polymers by Combustion Ion Chromatography Method

[0141] The concentration of fluorine was determined by combustion followed by ion chromatography analysis of the fluorides ions, per the method EN 14582:2016.

[0142] Determination of metals such as calcium and magnesium in PEEK article by ICP-OES

[0143] A clean, dry platinum crucible was placed onto an analytical balance, and the balance was zeroed. One half to 3 grams of pipe sample was weighed into a boat and its weight was recorded to 0.0001 g. The crucible with sample was placed in a muffle furnace (Thermo Scientific Thermolyne F6000 Programmable Furnace). The furnace was gradually heated to 525°C and held at that temperature for 10 hours to dry ash the sample. Following ashing, the furnace was cooled down to room temperature, and the crucible was taken out of the furnace and placed in a fume hood. The ash was dissolved in diluted hydrochloric acid. The solution was transferred to a 25 mL volumetric flask, using a polyethylene pipette. The crucible was rinsed twice with approximately 5 mL of ultrapure water (R<18 MQcm) and the washes were added to a volumetric flask to effect a quantitative transfer. Ultrapure water was added to total 25 mL in the flask. A stopper was put on the top of the flask and the contents were shaken well to mix.

[0144] ICP-OES analysis was performed using an inductively-coupled plasma emission spectrometer Perkin-Elmer Optima 8300 dual view. The spectrometer was calibrated using a set of NIST traceable multi-element mixed standards with analyte concentrations between 0.0 and 10.0 mg / L. A linear calibration curve was obtained in a range of concentrations with a correlation coefficient better than 0.9999 for each of 48 analytes. The standards were run before and after every ten samples to ensure instrument stability. The results were reported as an average of three replicates. The concentration of metals in the sample was calculated with the following equation: A = (B * C) / (D) where:A = concentration of element in the sample in mg / kg (=wt.ppm) B = element in the solution analysed by ICP-OES in mg / LC = volume of the solution analysed by ICP-OES in mL D = sample weight in grams used in the procedure.

[0145] Comparative Example 1 : PEEK with total amount of extractables > 3000 pq / g and an amount of Oligomer 1 > 70 pq / g

[0146] In a 500 mL 4-neck reaction flask fitted with a stirrer, a N2 inlet tube, a Claisen adapter with a thermocouple plunging in the reaction medium, and a Dean-Stark trap with a condenser and a dry ice trap were introduced 127.82 g of diphenyl sulfone, 28.685 g of hydroquinone and 57.213 g of 4,4’-difluorobenzophenone. The flask content was evacuated under vacuum and then filled with high purity nitrogen (containing less than 10 ppm O2). The reaction mixture was then placed under a constant nitrogen purge (60 mL / min).

[0147] The reaction mixture was heated slowly to 150 °C. At 150 °C, a mixture of 28.619 g of Na2COs and 0.180 g of K2CO3 was added via a powder dispenser to the reaction mixture over 30 minutes. At the end of the addition, the reaction mixture was heated to 320 °C at 1 °C / minute. The mixture was held at 320 °C until the target viscosity was reached, in this case for 34 minutes, then the reaction was terminated in 3 stages : 6.817 g of 4,4’-difluorobenzophenone were added to the reaction mixture while keeping a nitrogen purge on the reactor. After 5 minutes, 0.444 g of lithium chloride were added to the reaction mixture. 10 minutes later, another 2.227 g of 4,4’-difluorobenzophenone were added to the reactor and the reaction mixture was kept at temperature for 15 minutes.

[0148] The reactor content was then poured from the reactor into a SS pan and cooled. The solid was broken up and ground in an attrition mill through a 2 mm screen. Diphenyl sulfone and salts were extracted from the mixture by extracting successively with 6 times 1 .2 L of acetone and 7 times with 1 ,2L of DM water at room temperature. The powder was then dried at 120 °C under vacuum for 12 hours yielding 67 g of a white powder and its properties are detailed in Table 1 .

[0149] Example 1 : PEEK with total amount of extractables < 3000 pq / g and an amount of Oligomer 1 < 70 pq / g

[0150] In a 500 mL 4-neck reaction flask fitted with a stirrer, a N2 inlet tube, a Claisen adapter with a thermocouple plunging in the reaction medium, anda Dean-Stark trap with a condenser and a dry ice trap were introduced 127.82 g of diphenyl sulfone, 28.685 g of hydroquinone, 57.402 g of 4,4’- difluorobenzophenone and 0.485 g of 4-phenoxyphenol. The flask content was evacuated under vacuum and then filled with high purity nitrogen (containing less than 10 ppm O2). The reaction mixture was then placed under a constant nitrogen purge (60 mL / min).

[0151] The reaction mixture was heated slowly to 150 °C. At 150 °C, a mixture of 27.598 g of Na2COs and 0.720 g of K2CO3 was added via a powder dispenser to the reaction mixture over 30 minutes. At the end of the addition, the reaction mixture was heated to 200 °C and held for 1 h at that temperature, then heated up to 250 °C and held at 250 °C for 1 h. Finally, the reaction mixture was heated to 315 °C and held at 315 °C until the target viscosity was reached, in this case for 57 minutes.

[0152] The reactor content was then poured from the reactor into a SS pan and cooled. The solid was broken up and ground in an attrition mill through a 2 mm screen. Diphenyl sulfone and salts were extracted from the mixture by extracting successively with 6 times 1 ,2L of acetone and 7 times with 1 ,2L of DM water at room temperature. The powder was then dried at 120 °C under vacuum for 12 hours yielding 67 g of a white powder and its properties are detailed in Table 1 .

[0153] Example 2: PEEK with total amount of extractables < 3000 pq / g and an amount of Oligomer 1 < 70 pq / g

[0154] In a 500 mL 4-neck reaction flask fitted with a stirrer, a N2 inlet tube, a Claisen adapter with a thermocouple plunging in the reaction medium, and a Dean-Stark trap with a condenser and a dry ice trap were introduced 127.82 g of diphenyl sulfone, 28.685 g of hydroquinone, 57.402 g of 4,4’- difluorobenzophenone and 0.490 g of phenol. The flask content was evacuated under vacuum and then filled with high purity nitrogen (containing less than 10 ppm O2). The reaction mixture was then placed under a constant nitrogen purge (60 mL / min).

[0155] The reaction mixture was heated slowly to 150 °C. At 150 °C, a mixture of 27.598 g of Na2COs and 0.720 g of foCC was added via a powder dispenser to the reaction mixture over 30 minutes. At the end of the addition, the reaction mixture was heated to 200 °C and held for 1 h at thattemperature, then heated up to 250 °C and held at 250 °C for 1 h. Finally, the reaction mixture was heated to 315 °C and held at 315 °C until the target viscosity was reached, in this case for 1 hi 1 minutes.

[0156] The reactor content was then poured from the reactor into a SS pan and cooled. The solid was broken up and ground in an attrition mill through a 2 mm screen. Diphenyl sulfone and salts were extracted from the mixture by extracting successively with 6 times 1 ,2L of acetone and 7 times with 1 ,2L of DM water at room temperature. The powder was then dried at 120 °C under vacuum for 12 hours yielding 67 g of a white powder and its properties are detailed in Table 1 .

[0157] Example 3: PEEK with total amount of extractables < 3000 pq / g and an amount of Oligomer 1 < 70 pq / g

[0158] In a 500 mL 4-neck reaction flask fitted with a stirrer, a N2 inlet tube, a Claisen adapter with a thermocouple plunging in the reaction medium, and a Dean-Stark trap with a condenser and a dry ice trap were introduced 127.82 g of diphenyl sulfone, 28.685 g of hydroquinone and 57.213 g of 4,4’-difluorobenzophenone. The flask content was evacuated under vacuum and then filled with high purity nitrogen (containing less than 10 ppm O2). The reaction mixture was then placed under a constant nitrogen purge (60 mL / min).

[0159] The reaction mixture was heated slowly to 150 °C. At 150 °C, a mixture of 28.619 g of Na2COs and 0.180 g of K2CO3 was added via a powder dispenser to the reaction mixture over 30 minutes. At the end of the addition, the reaction mixture was heated to 320 °C at 1 °C / minute. The mixture was held at 320 °C until the target viscosity was reached, in this case for 14 minutes, then the reaction was terminated in 2 stages : 0.839 g of 1 ,4-bis(4’-fluorobenzoyl)benzene were added to the reaction mixture while keeping a nitrogen purge on the reactor. After 5 minutes, 0.444 g of lithium chloride were added to the reaction mixture. The reactor content was then poured from the reactor into a SS pan and cooled. The solid was broken up and ground in an attrition mill through a 2 mm screen. Diphenyl sulfone and salts were extracted from the mixture by extracting successively with 6 times 1 .2 L of acetone and 7 times with 1 ,2L of DM water at room temperature. The powder was then dried at 120 °C undervacuum for 12 hours yielding 67 g of a white powder and its properties are detailed in Table 1 .

[0160] Example 4: PEEK with total amount of extractables < 3000 pq / g and an amount of Oligomer 1 < 70 pq / g

[0161] The same procedure as for CE1 was followed except that the polymer was washed with 6 times 1 .2 L of dimethylformamide and 8 times with 1 ,2L of DM water at room temperature. The polymer properties are detailed in Table 1 .

[0162] Example 5: PEEK with total amount of extractables < 3000 pq / g and an amount of Oligomer 1 < 70 pq / g

[0163] In a 500 mL 4-neck reaction flask fitted with a stirrer, a N2 inlet tube, a Claisen adapter with a thermocouple plunging in the reaction medium, and a Dean-Stark trap with a condenser and a dry ice trap were introduced 127.82 g of diphenyl sulfone, 28.685 g of hydroquinone and 57.213 g of 4,4’-difluorobenzophenone. The flask content was evacuated under vacuum and then filled with high purity nitrogen (containing less than 10 ppm O2). The reaction mixture was then placed under a constant nitrogen purge (60 mL / min).

[0164] The reaction mixture was heated slowly to 150 °C. At 150 °C, a mixture of 28.619 g of Na2COs and 0.180 g of K2CO3 was added via a powder dispenser to the reaction mixture over 30 minutes. At the end of the addition, the reaction mixture was heated to 320 °C at 1 °C / minute. The mixture was held at 320 °C until the target viscosity was reached, in this case for 14 minutes, then the reaction was terminated in 2 stages : 1 .136 g of 4,4’-difluorobenzophenone were added to the reaction mixture while keeping a nitrogen purge on the reactor. After 7 minutes, 0.444 g of lithium chloride were added to the reaction mixture. The reactor content was then poured from the reactor into a SS pan and cooled. The solid was broken up and ground in an attrition mill through a 2 mm screen. Diphenyl sulfone and salts were extracted from the mixture by extracting successively with 6 times 1 .2 L of acetone and 7 times with 1 ,2L of DM water at room temperature. The powder was then dried at 120 °C under vacuum for 12 hours yielding 67 g of a white powder and its properties are detailed in Table 1 .

[0165] Example 6: PEEK with total amount of extractables < 3000 pq / g and an amount of Oligomer 1 < 70 pq / g

[0166] In a 500 mL 4-neck reaction flask fitted with a stirrer, a N2 inlet tube, a Claisen adapter with a thermocouple plunging in the reaction medium, and a Dean-Stark trap with a condenser and a dry ice trap were introduced 127.82 g of diphenyl sulfone, 28.685 g of hydroquinone and 57.213 g of 4,4’-difluorobenzophenone. The flask content was evacuated under vacuum and then filled with high purity nitrogen (containing less than 10 ppm O2). The reaction mixture was then placed under a constant nitrogen purge (60 mL / min).

[0167] The reaction mixture was heated slowly to 150 °C. At 150 °C, a mixture of 28.619 g of Na2COs and 0.180 g of K2CO3 was added via a powder dispenser to the reaction mixture over 30 minutes. At the end of the addition, the reaction mixture was heated to 320 °C at 1 °C / minute. The mixture was held at 320 °C until the target viscosity was reached, in this case for 15 minutes, then the reaction was terminated in 3 stages : 6.256 g of 4-fluorobenzophenone were added to the reaction mixture while keeping a nitrogen purge on the reactor. After 5 minutes, 0.444 g of lithium chloride were added to the reaction mixture. 10 minutes later, another 2.085 g of 4-fluorobenzophenone were added to the reactor and the reaction mixture was kept at temperature for 15 minutes.

[0168] The reactor content was then poured from the reactor into a SS pan and cooled. The solid was broken up and ground in an attrition mill through a 2 mm screen. Diphenyl sulfone and salts were extracted from the mixture by extracting successively with 6 times 1 .2 L of acetone and 7 times with 1 ,2L of DM water at room temperature. The powder was then dried at 120 °C under vacuum for 12 hours yielding 67 g of a white powder and its properties are detailed in Table 1 .Table 1

[0169] The analysis of the Soxhlet extracts by liquid chromatography shows that the polymer produced according to the invention contains reduced amounts of oligomers, and therefore generates less offgases when molten. Indeed in extrusion trials it was shown that the inventive PEEK Polymer, having low total amount of extractables and an amount of Oligomer 1 lower than 70 pq / g, had no or reduced amounts of die deposit.

[0170] General procedure for the pelletization of PEEK powder

[0171] PEEK powder prepared under the conditions detailed above (but at a larger scale) was pelletized by melt processing on a 26 mm diameter Coperion® co-rotating partially intermeshing twin screw extruder having an L / D ratio of 48:1 . The extruder was equipped with 12 barrel sections, with barrel sections 2 through 12 being temperature controlled. The extruder was fitted with a 3-mm diameter single-hole die. The resin feeder fed into the feed hopper (barrel section 1 ). Vacuum venting with a vacuum level > 25 in Hg was applied at barrel section 10 during the compounding to strip off moisture and any possible residual volatiles from the compounds. The extrudate from each of the compositions was stranded and the strands were cooled in a water trough and then pelletized using a Maag Primo 60 E pelletizer into pellets. See Table 2 for extrusion conditions.Table 2

[0172] Example 7 - Preparation of Pellets of the PEEK polymers of Comparative Example 1, Examples 2 and 5

[0173] The extrusion of PEEK lots was made according to the general procedure. No white residue was observed on the die during the preparation of pellets using the PEEK polymers of Examples 2 and 5, while a white residue was observed for the polymer of Comparative Example 1 .

[0174] Example 8 : Pipe extrusion PEEK polymer of Example 2

[0175] 16mm PEEK pipes were extruded using a 45 mm non-vented extruder.The pellets were extruded in a single barrier screw with L / D ratio of 26, the length of the feeding section was 6 D, the transition section was 12 D long and the final metering length was 8 D long. The compression ratio (the ratio between the flight height in the feeding zone to the one in the metering zone) was equal to 2. No breaker plate with filtering screen pack was used. The pellets did not contain any lubricant.

[0176] A Draw Down Ratio (defined as the ratio between the final section of the pipe and the exit circular crown area of the die) of 2.14 was used. A standard vacuum bath filled with cold water was used to calibrate the pipes. The thickness of the pipes was 1 ,5mm and was adjusted through throughput and line speed. Pellets were dried for 4 hours at 120°C before feeding the hopper in a flooded feeding mode. The temperature profile of the extruder is provided in Table 3.Table 3

[0177] No die deposits were observed. Good results of tube thickness consistency were obtained. The maximum thickness variation measured was 0.26mm and no points had a thickness variation above 0.135mm (120% of the nominal pipe thickness). The pipe external diameter visual aspect was constant, free of any transparent area.

[0178] The pipe was analyzed by ICP-OES for residual Ca and Mg and shown to contain 3 ppm of calcium and 1 ppm of magnesium.

[0179] The Soxlhet extraction on ground pipe samples following the procedure for pellets and pipes gave the same values as for the starting pellets.

Claims

Claims1 . Use of a PEEK polymer powder to manufacture articles for transporting ultra-pure water comprising at least one surface intended to be in contact with ultra-pure water, wherein the PEEK polymer powder is characterised by a total amount of extractables of no more than 3000 pg / g and by an amount of Oligomer 1 of no more than 70 pg / g[Oligomer 1], and wherein the amount of extractables and of Oligomer 1 are determined by Soxhlet extraction with acetone for 48 hours followed by liquid chromatography.

2. The use of claim 1 wherein the PEEK polymer comprises at least 80 mol%, preferably at least 85 mol%, more preferably at least 90 mol%, even more preferably at least 95 mol%, at least 98 mol%, at least 99 mol% or 100 mol% of units of formula (RPEEK):and up to 1 mol%, up to 2 mol%, up to 5 mol%, up to 10 mol%, up to 15 mol% or up to 20 mol% of at least one unit having formula (K-A) to (K-P):wherein each R’ is independently selected from halogen, an alkyl, an alkenyl, an alkynyl, an aryl, an ether, a thioether, a carboxylic acid, an ester, an amide, an imide, an alkali or an alkaline earth metal sulfonate, an alkyl sulfonate, an alkali or alkaline earth metal phosphonate, an alkyl phosphonate, an amine and a quaternary ammonium; and each j’ is independently 0 or an integer from 1 to 4.

3. Process for the manufacture of articles for transporting ultra-pure water comprising at least one surface intended to be in contact with ultra-pure water, the process comprising a step of melt processing the PEEK polymer powder as defined in claim 1 or 2.

4. The process of claim 3 which comprises the steps of:(a) providing the PEEK polymer powder as defined in claim 1 or 2;(b) melt processing said PEEK polymer powder to provide PEEK polymer pellets; and(c) forming said PEEK polymer pellets into at least one article for transporting ultra-pure water, preferably into the surface of the article intended to be in contact with ultra-pure water.

5. The process according to claim 4 wherein the PEEK polymer pellets in step (c) do not contain any lubricant.

6. The process according to claim 4 which further comprises the step of adding lubricant to the PEEK polymer pellets either before or during step (c).

7. The process according to any one of claims 4 to 6, wherein step (c) is performed by extrusion and said PEEK polymer has:- a number average molecular weight (Mn) higher than 42,000, preferably higher than 43,000, more preferably higher than 44,000, as measured by GPC at 160 °C in 1 , 2, 4-trichlorobenzene: Phenol (50:50) using PS standards, and / or lower than 58,000, preferably lower than 57,000, more preferably lower than 56,000, as measured by GPC at 160 °C in 1 ,2,4-trichlorobenzene: phenol (50:50) using PS standards; and / or- a weight average molecular weight (Mw) higher than 90,000, more preferably higher than 95,000, even more preferably higher than 97,000, as measured by GPC at 160 °C in 1 ,2, 4-trichlorobenzene: Phenol (50:50) using PS standards, and / or lower than 125,000, more preferably lower than 120,000, even more preferably lower than 115,000, and still more preferably lower than 110,000, as measured by GPC at 160 °C in 1 ,2,4- trichloro- benzene:phenol (50:50) using PS standards.

8. The process according to any one of claims 4 to 6, wherein step (c) is performed by injection moulding and said PEEK polymer has:- a number average molecular weight (Mn) higher than 29,000, preferably higher than 30,000, preferably higher than 31 ,000, as measured by GPC at 160 °C in 1 ,2, 4-trichlorobenzene: Phenol (50:50) using PS standards, and / or lower than 54,000, more preferably lower than 53,000, even more preferably lower than 52,000, as measured by GPC at 160 °C in 1 ,2,4- trichlorobenzene: Phenol (50:50) using PS standards; and / or- a weight average molecular weight (Mw) higher than 60,000, preferably higher than 62,000, more preferably higher than 63,000, as measured by GPC at 160 °C in 1 ,2, 4-trichlorobenzene: Phenol (50:50) using PS standards, and / or lower than 110,000, more preferably lower than 108,000, even more preferably lower than 107,000, as measured by GPC at 160 °C in 1 ,2, 4-trichlorobenzene: Phenol (50:50) using PS standards.

9. An article for transporting ultra-pure water comprising a surface intended to be in contact with ultra-pure water comprising a PEEK polymer, said surface being characterised by a total amount of extractables of no more than 3000 pg / g and by an amount of Oligomer 1 of no more than 70 pg / g,[Oligomer 1], the amount of extractables and of Oligomer 1 being determined by Soxhlet extraction with acetone for 48 hours followed by liquid chromatography.

10. The article according to claim 9 wherein the total amount of extractables is no more than 2000 pg / g.11 . The article according to claim 9 or 10 in which the amount of cations of Ca, Mg or Zn is no more than 5 ppm, as measured by ICP-OES (inductively coupled plasma coupled with optical emission spectroscopy) after mineralization by ashing in a platinum crucible.

12. The article according to any one of claims 9 to 11 which consists of the PEEK polymer.

13. The article of any one of claims 9 to 12 which is a pipe or a pipe connector.

14. The pipe of claim 13 which contains ultra-pure water and / or when tested according to protocol (p1 ) as described in the specification is characterized by an amount of eluted impurities (IMP), expressed in pg / m2of the surface of the leaching area, lower than the values of eluted impurities indicated in the Table below:

15. The pipe of claim 13 or 14 that has a thickness between 1 and 200 mm and / or a length between 20 and 150 mm.

16. The length of the pipe is generally at most 100 m.

17. The pipe connector of claim 13, which contains ultra-pure water and / or when tested according to protocol (p2) as described in the specification is characterized by an amount of eluted impurities (IMP), expressed in pg / m2of the surface of the leaching area, lower than the values of eluted impurities indicated in the Table below.

18. The pipe or pipe connector of any one of claims 13 to 17 wherein the ultra- pure water is a water exhibiting an electric resistivity at 25°C of at least 18.0 MO. cm and a Total Organic Carbon (TOC) of at most 10.0 pg / L.

19. A system for transporting ultra-pure water comprising the article, pipe or pipe connector of any one of claims 9 to 18.

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