System for transporting ultrapure water (UPW)

Abstract

The present invention relates to a system and components thereof made from poly(aryl ether ketone) polymers, for use in transport of ultrapure water.

Description

DescriptionSystem for transporting ultrapure water (UPW)Reference to related applicationsThis application claims priority from US provisional application No. 63 / 584736 filed on 22 September 2023 and from European patent application No. 23201973.7 filed on 5 October 2023, the whole content of each of these applications being incorporated herein by reference for all purposes.Technical Field

[0001] The present invention relates to the transport of ultrapure water (UPW).Background Art

[0002] Ultra Pure water (UPW) is employed in many steps of fabrication of semiconductors. 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 also needed as the integration of semiconductors advances further.

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

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

[0005] The preparation of UPW involves the removal of ions, organic and biological contaminants and particulates. UPW typically exhibits an electric resistivity at 25°C of 18.1 MQ.cm or higher and a Total Organic Carbon level (TOC) of maximum 10.0 pg / L. Bacterial contamination can also be limited to 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 (UPW) for use in the semiconductor industry.

[0007] JPH04367781A discloses an ultrapure water transport piping system comprising a terminal ultrafiltration device or the terminal reverse osmosis membrane device and wherein the piping material used after the ultrafiltration or reverse osmosis device is made of a thermoplastic polymer containing a hydrotalcite compound or / and a hydrotalcite. PEEK is mentioned among the thermoplastic polymers.

[0008] With the development of smaller chips, the level of purity required for UPW is such that PVDF is no longer adapted in the entire transport system, notably due to the leaching of organic impurities and fluoride anions in places where higher temperatures are used (80-120°C). Indeed, the general trend today is to produce electronic circuits with smaller and smaller line-widths. Today, some electronics producers offer commercially available chips with a linewidth of around 400 nm. However, in research projects, even smaller linewidths down to 10 or even 5 nm have been reported.

[0009] Polyetheretherketone (PEEK) has been described as particularly well adapted for replacing PVDF in the transportation of UPW at higher temperature (80-120°C typically) as it presents a reduced level of leaching as compared to PVDF.

[0010] However, because of its high melting temperature (340-345°C) the processing of PEEK requires a very high temperature (above 360°C). Also, the difficulty in melting the PEEK negatively affects its feeding to the extruder as well as the entire extrusion process.

[0011] The use of PEEK polymers for the manufacture of pipings used in the treatment of UPW is known in the art, for example from US4784772 (in the name of Mitsui Toatsu Chemical Incorporated).Summary of invention

[0012] The Applicant is aware that in general, the use of at least one lubricant allows for easier processing of PEEK polymer during extrusion, hence requiring lower processing temperatures without impacting the bulk PEEK properties such as Tg, mechanical properties and melt strength. The improved processing is associated with more constant feeding of the PEEK and more consistent extrusion process. In injection molding, the improvement is associated with improved screw recovery during the plasticization phase. The use of lower processing temperature also causes less degradation and off gassing of high boiling impurities present in PEEK (such as residual solvent, monomers and oligomers), leading to reduced deposit on the die. Because of the more consistent processing, the final article has a consistent thickness, with less than 20% variation from nominal thickness.

[0013] However, the use of lubricant(s) is not recommended for applications requiring ultra / high purity.

[0014] Facing the problem of providing a polymer for the manufacture of a system suitable for transporting Ultra Pure Water (UPW), the Applicant surprisingly found that when a very small amount of at least one lubricant is added on the surface of PEEK pellets, not only the lubricated PEEK pellets exhibit a more consistent processing (with no surge) and retain the bulk properties (eg. high Tg, good mechanical properties, good melt strength) but unexpectedly such PEEK pellets also meet the stringent purity requirement of the UPW transport application, as measured by surface extraction using semiconductor industry standards.Description of the invention

[0015] In a first aspect, the present invention relates to a system for transporting ultra pure water (UPW) comprising at least one component having a surface intended to be in contact with UPW, said at least one component comprising a composition comprising: polyetheretherketone (PEEK) and at least one metal selected from Ca, Mg and / or Zn in an amount from 5 to 20 ppm based on the amount of PEEK and as measured on the component by inductively coupled plasma coupled with optical emission spectroscopy (ICP-OES) after mineralization by ashing in a platinum crucible.

[0016] Said at least one component can be selected for example from pipe(s) and pipe connector(s) (also referred to as “pipe fitting(s)”).

[0017] 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.

[0018] More preferably, said pipe connector is selected in the group comprising: 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)”).

[0019] Preferably, said component has a crystallinity level as measured by DSC on the first heat scan of at least 20%, preferably at least 25%. The level of crystallinity is determined by measuring the heat of fusion on the first heat scan and assuming that 100% crystalline PEEK has a heat of fusion of 130 J / g.

[0020] In a second aspect, the present invention relates to a pipe for transporting ultra pure water (UPW) having a surface intended to be in contact with UPW, said pipecomprising a composition comprising: PEEK and at least one metal selected from Ca, Mg and / or Zn in an amount from 5 to 20 ppm based on the amount of PEEK and as measured on said pipe by inductively coupled plasma coupled with optical emission spectroscopy (ICP-OES) after mineralization by ashing in a platinum crucible.

[0021] In a third aspect, the present invention relates to a pipe connector comprising a surface intended to be in contact with UPW, said pipe connector comprising a composition comprising: PEEK and at least one metal selected from Ca, Mg and / or Zn in an amount from 5 to 20 ppm based on the amount of PEEK and as measured on said pipe connector by inductively coupled plasma coupled with optical emission spectroscopy (ICP-OES) after mineralization by ashing in a platinum crucible.

[0022] The Applicant surprisingly found that the use of lubricated PEEK pellets allows to lower the temperatures required to melt and shape the PEEK pellets into the component, while also meeting the stringent purity requirements of the UPW transport application, as measured by surface extraction using semiconductor industry standards.

[0023] Without being bound by any theory, the Applicant surprisingly found that component of the system according to the present invention has a consistent wall thickness.

[0024] 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 at least one point, preferably at at least two or more points, of the wall of the component.

[0025] The consistent wall thickness of the component of the system according to the present invention is of particular interest when such a component is a pipe.

[0026] 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 at at least one point, preferably at at least two or more points, of the wall of the pipe.

[0027] 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 at at least one point, preferably at at least two or more points, of the wall of the pipe connector.

[0028] In a further aspect, the present invention relates to a system for transporting ultra pure water (UPW) comprising at least one component having a surface intendedto be in contact with UPW, said surface being made from pellets comprising PEEK and at least one lubricant adhered on at least an area of the external surface of said pellets [lubricated PEEK pellets],

[0029] Said component is preferably selected from pipe(s) and pipe connector(s), as defined above.

[0030] In a further aspect, the present invention relates to a pipe for transporting ultra pure water (UPW) having a surface intended to be in contact with UPW, said surface being made from pellets comprising PEEK and at least one lubricant adhered on at least an area of the external surface of said pellets [lubricated PEEK pellets],

[0031] In still another aspect, the present invention relates to a pipe connector comprising a surface intended to be in contact with UPW, said surface being made from pellets comprising PEEK and at least one lubricant adhered on at least an area of the external surface of said pellets [lubricated PEEK pellets],

[0032] The system of the present invention also comprises at least one means for creating a difference of pressure to transport the water, for example a pump.

[0033] In the system of the present invention, said component is prepared by techniques such as (co)extrusion or injection moulding.

[0034] Preferably, the pipe is prepared by (co)extrusion.

[0035] Preferably, the pipe connector is prepared by injection moulding.

[0036] The pipe comprises one or more layers. The internal layer intended to be in contact with water is made from the lubricated PEEK pellets as described above.

[0037] According to an embodiment (E1), the pipe of the invention 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.

[0038] 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 at least one point, preferably at at least two or more points of the pipe.

[0039] 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 (L). 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 water, there is less risk of contaminating the water with molecules leached from these layers. As a consequence, this / theselayer(s) other than layer (L) may thus comprise at least one filler and / or at least plastic additive. The multilayer pipe can be prepared by coextrusion or by overmolding the other layer(s) around layer (L).

[0040] 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 at least two or more points of the pipe.

[0041] 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 colourants (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, antiblocking agents and combinations thereof.

[0042] More particularly according to embodiment (E2), the pipe of the invention comprises:- an internal layer (or wall) (L) intended to be in contact with water, said layer (L) being made from the lubricated PEEK pellets as defined above;- 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 colourants (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.

[0043] The pipe of the invention can be used to transport UPW since the layer (L) intended to be in contact with water is made from the lubricated PEEK pellets disclosed above.

[0044] The pipe can be characterised by the amounts of eluted impurities given below.

[0045] The pipe contains UPW and / or is characterised by the amounts of eluted impurities given below.

[0046] 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 UPW systems to assess whether the material can suitably be used without contaminating UPW. Pursuant to these norms, thefollowing protocol (p1) can be used for measuring the amounts of the eluted impurities:

[0047] The pipe of the invention is such that following the above mentioned protocol, the amounts of elution of the impurities (Imp) released from layer (L) after bringing layer (L) in contact with UPW at 85°C for 7 days are less than the values indicated in the Table below:

[0048] The amounts of eluted impurities are expressed in pg / m2of the surface of layer(L) in contact with water.

[0049] The diameter of the pipe is generally between 1 and 200 mm. The diameter may more particularly be between 20 and 150 mm.

[0050] The length of the pipe is generally at most 100 m. The length may more particularly be at most 50 m.

[0051] The pipe connector of the invention can be used to transport UPW since the surface intended to be in contact with water is made from the lubricated PEEK pellets disclosed above.

[0052] 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:

[0053] 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 UPW are less than the values of eluted impurities expressed in pg / m2of the surface of the leaching area indicated in the Table below:

[0054] In the system according to the present invention, said at least one component contains some residue from the lubricant such as calcium, magnesium or zinc, which, surprisingly, do not affect the level of surface extractable impurities of interest for the semiconductor industry (cations, TOC).

[0055] Preferably, the amount of Ca, Mg and / or Zn in the component is in the range from 7 to 18 ppm, as measured on the component by ICP-OES (inductively coupled plasma coupled with optical emission spectroscopy) after mineralization by ashing in a platinum crucible.

[0056] In a further aspect, the present invention relates to a method for manufacturing a component for transporting ultra pure water (UPW), said component being preferably selected from a pipe or a pipe connector, said method comprising:(a) providing pellets comprising PEEK and at least one lubricant adhered on at least an area of the external surface of said pellets [lubricated PEEK pellets],(b) melting said lubricated PEEK pellets, thus providing melted pellets, and(c) forming said melted pellets into at least one component for transporting UPW.

[0057] Preferably, said step (c) of forming can be performed by methods such as extrusion or injection moulding. The method can be properly selected based on the component to be formed.

[0058] In another aspect, the present invention relates to the use of pellets comprising PEEK and at least one lubricant on at least an area of the external surface of said pellets, for the manufacture of a component for transporting ultra pure water, said component being preferably selected from pipe and pipe connectors.

[0059] The method for manufacturing the lubricated PEEK pellets is not limited.

[0060] Preferably, such lubricated PEEK pellets are manufactured by a process comprising:(i) providing pellets comprising PEEK and free from any lubricant, and(ii) contacting at least an area of the external surface of said pellets comprising PEEK with at least one lubricant.

[0061] More preferably, said step (ii) of contacting is performed by dry mixing.

[0062] Advantageously, the lubricant is selected from compounds that degrade at the processing temperature.

[0063] As used herein, “degrade” means that the lubricant exhibits 15% or more of weight loss at 300°C, as measured by thermo gravimetric analysis (TGA).

[0064] Preferably, the lubricant is a low melting hydrocarbon-based lubricant, more preferably characterised by a melting point below 250 °C, even more preferably below 200 °C.

[0065] 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.

[0066] 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.

[0067] Preferably, the lubricated PEEK pellets have a diameter between 0.9 and 4.5 mm, more preferably between 1.9 and 3.2 mm.

[0068] Preferably, the lubricated PEEK pellets have a length between 1.5 and 4.8 mm, more preferably between 2.2 and 3.5 mm.

[0069] The diameter and the length of the pellets can be measured by any means. For instance diameter and length of the pellets may be measured using a caliper

[0070] Preferably, said lubricated PEEK pellets comprise lubricant in an amount of from 25 to 500 ppm, more preferably from 50 to 250 and even more preferably from 75 to 125 ppm, based on the amount of PEEK.

[0071] Preferably, said lubricated PEEK pellets comprise PEEK in an amount of at least 50 wt.%, more preferably at least 60 wt.%, 70 wt.%, 85 wt.%, 95 wt.%, 99.9 wt.% based on the total weight of said pellets.

[0072] Advantageously, said lubricated PEEK pellets consist of PEEK in an amount of 100 wt.% based on the total weight of said pellets.

[0073] When the amount of PEEK is below 100 wt.%, said lubricated PEEK pellets can comprise at least one other polymer. Such at least one other polymer can beselected from polysulfone (PSU), polyphenylene sulfone (PPSLI), polyetherimide (PEI), one or more other polyarylether ketone (PAEK).

[0074] Each of said at least one other polymer can be present in an amount from 0.1 wt.% to 5 wt.%, 15 wt.%, 30 wt.%, 40 wt.%, 50 wt.% based on the total weight of said pellets.

[0075] When step (c) is performed by extrusion, said PEEK is characterised by a properly selected number average molecular weight (Mn) and / or weight average molecular weight (Mw) range, which allows to compromise between melt strength, ductility and low viscosity for ease of processing. Such selection also contributes to the consistent processing.

[0076] Advantageously, said PEEK has a Mn higher than 42,000, preferably higher than 43,000, more preferably higher than 44,000, as measured by GPC at 160 °C in1.2.4-trichlorobenzene:phenol (50:50) using polystyrene (PS) standards.

[0077] Preferably, said PEEK has a Mn 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.

[0078] Advantageously, said PEEK has a 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.

[0079] Preferably, said PEEK has 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, as measured by GPC at 160 °C in 1 , 2, 4-tri chlorobenzene: Phenol (50:50) using PS standards.

[0080] When step (c) is performed by injection moulding, said PEEK is characterised by a properly selected number average molecular weight (Mn) and / or weight average molecular weight (Mw) range, which allows to compromise between melt strength, ductility and low viscosity for ease of processing. Such selection also contributes to the consistent processing.

[0081] Advantageously, said PEEK has a 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.

[0082] Preferably, said PEEK has a Mn 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.

[0083] Advantageously, said PEEK has a Mw higher than 60,000, preferably higher than 62,000, more preferably higher than 63,000, as measured by GPC at 160 °C in1.2.4-trichlorobenzene:Phenol (50:50) using PS standards.

[0084] Preferably, said PEEK has Mw 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.

[0085] Without being bound by any theory, the selection of the above mentioned range 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.

[0086] Preferably, said PEEK comprises 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% and even most preferably 100 mol% of units of formula (RPEEK):

[0087] Preferably, when the PEEK comprises less than 100 mol% of units of formula (RPEEK) as represented above, said PEEK can comprise up to 1 mol%, up to 2 mol%, up to 5 mol%, up to 10 mol% or up to 15 mol% of at least one unit having formula (K-A) to (K-M) 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.

[0088] In still another aspect, the present invention relates to a method for transporting UPW, wherein at least one pipe or a pipe connector as defined above is used.Experimental Section

[0089] Raw Materials

[0090] Hydroquinone, 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.

[0091] 4,4’-Difluorobenzophenone, 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 WO 2012 / 001131.

[0092] Diphenyl sulfone (polymer grade) was procured from Proviron (99.8% pure).

[0093] Sodium carbonate, light soda ash, was procured from Solvay S.A., France.

[0094] Potassium carbonate with a d90 < 45 pm was procured from Armand products.

[0095] Lithium chloride (anhydrous grade) was procured from Acros.

[0096] Calcium stearate was procured from Sigma Aldrich.

[0097] Determination of Mn and Mw by Gel Permeation Chromatography (GPC)

[0098] Molecular weights of the sample were determined by PL 220 high temperature GPC system using conditions described in Table 1 below.Table 1

[0099] 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)

[0100] Determination of the level of crystallinity of final article

[0101] 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.

[0102] 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.

[0103] The melting 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 offusion measured on the 1st heat scan. The % crystallinity is defined as 100 x heat of fusion (J / g) / 130 (J / g).

[0104] Determination of surface extractable impurities per SEMI-40

[0105] 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.

[0106] 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’.

[0107] 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.

[0108] 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.

[0109] The surface extractable metals (SEMI F57 list) were measured by high resolution ICP-MS using a Thermo Element 2 instrument.

[0110] The surface extractable anions (SEMI F57 list) were measured by ion chromatography (IC) using a Dionex ICS-5000 instrument.

[0111] 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.

[0112] Measurement of thickness of tubes

[0113] The thickness of the tubes was measured with a X-rays system using a Zumbach RAYEX S XT110 equipment.

[0114] The tube to be tested runned 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 tocalculate and create a reconstructed image of the diameter, thicknesses, out of roundness and eccentricity. The system had a resolution of 5 micron.

[0115] Determination of Elemental Impurities such as calcium and magnesium in PEEK article by ICP-OES

[0116] 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.

[0117] 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 elemental impurities 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 / L C = volume of the solution analysed by ICP-OES in mL D = sample weight in grams used in the procedure.

[0118] Example 1: preparation of PEEK pellets

[0119] In a 1000 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-Starktrap with a condenser and a dry ice trap, the following were introduced: 343.630 g of diphenyl sulfone, 77.121 g of hydroquinone and 153.866 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).

[0120] The reaction mixture was heated slowly to 150 °C. At 150 °C, a mixture of 76.939 g of Na2CC>3 and 0.484 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. After 73 minutes at 320 °C, the reaction was terminated in 3 stages: 18.336 g of 4,4’-difluorobenzophenone were added to the reaction mixture while keeping a nitrogen purge on the reactor. After 5 minutes, 1.188 g of lithium chloride were added to the reaction mixture. 10 minutes later, another 6.112 g of 4,4’-difluorobenzophenone was added to the reactor and the reaction mixture was kept at temperature for 15 minutes.

[0121] 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 acetone and water at room temperature. The powder was then dried at 120 °C under vacuum for 12 hours yielding 188 g of a white powder. The material had a Mn of 50,000 and Mw of 100,000 (PDI = 2.00)

[0122] 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.

[0123] Pelletization conditions are reported in Table 2 below.Table 2

[0124] Example 2: addition of lubricant to PEEK pellets

[0125] The pellets prepared according to Example 1 were dusted with 100 ppm of calcium stearate, relative to PEEK, and tumbled in a drum for 2 hours for dispersion.

[0126] Example 3: injection moulding

[0127] The pelletized material obtained according to Example 2 was injection moulded into plaques (51 mm x 76 mm x 2.5 mm) on a 150 ton Toshiba molding machine fitted with a 2.3:1 compression ratio screw. The 28 mm barrel had 4 heating zones using the conditions detailed in the following Table 3. The plaques were then annealed at 200 °C / 3 h before testing.Table 3

[0128] The surface extractable ions and total organics (TOC) were measured for PEEK of Example 2 and are listed in table 4.Table 4

[0129] The levels detected matched the expected requirements for the transport of ultra pure water, indicating that the low melting PEEK of the invention matches the purity requirement for the final application.

[0130] Example 4 : pipe extrusion according to the invention

[0131] 16 mm PEEK pipes were extruded using a 45 mm extruder. A Draw Down Ratio (DDR) 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 1.5 mm and was adjusted through throughput and line speed. Pellets were dried for 4 hours at 120°C before feeding the hopper in a flood fed mode.

[0132] The screw used was a standard three zone (feeding, transition, metering) L / D 26 screw. An almost flat temperature profile was used, as reported in Table 5.Table 5

[0133] The pipes thus obtained had a smooth external surface and had a constant thickness.

[0134] Wall thicknesses were measured on 4 points on 2 axes using a x-ray system, on 2 cm length.

[0135] The maximum thickness variation measured was of 0.040 mm, which was considered acceptable, and no point had a thickness variation above 0.315 mm (corresponding to 20% of the nominal pipe thickness).

[0136] The final pipe was analysed by ICP-OES and shown to contain 13 ppm calcium.

[0137] Example 5 : pipe extrusion of non-lubricated PEEK (of comparison)

[0138] As a comparison, pipes were manufactured with PEEK pellets with no lubricant on their external surface, following the method disclosed in Example 4 above. An almost flat temperature profile was used, as reported in Table 6.Table 6

[0139] The pipes thus obtained showed high thickness variations.

[0140] It was not possible to manufacture pipes with constant thickness. The cone polymer coming outside of the die into the calibration bath was pulsing. From the hopper it was possible to see some breathing effect due to pellets going backwards along the screw.

[0141] Wall thicknesses were measured on 4 points on 2 axes using a x-ray system, on 2 cm length.The maximum thickness variation measured was of 1.08 mm, and 4 points had a thickness variation above 0.30 mm (20% of the nominal pipe thickness), which was considered as not acceptable. Such a thickness variation was visible by eye, as on the lowest thickness the pipe wall was transparent. That pattern was repeated every 20 cm.

[0142] The final pipe was analysed by ICP-OES and shown to contain 3 ppm calcium.

Claims

Claims1. A system for transporting ultra pure water (UPW) comprising at least one component having a surface intended to be in contact with UPW, said at least one component a composition comprising polyetheretherketone (PEEK) and at least one metal selected from Ca, Mg and / or Zn in an amount from 5 to 20 ppm based on the amount of PEEK and as measured on the component by inductively coupled plasma coupled with optical emission spectroscopy (ICP-OES) after mineralization by ashing in a platinum crucible.

2. The system according to Claim 1 , wherein said component has:- a crystallinity level of at least 20%, as measured by DSC by measuring the heat of fusion on the first heat scan and assuming that 100% crystalline PEEK has a heat of fusion of 130 J / g; and / or- a thickness variation of its wall of less than 20% from the nominal wall thickness, as measured by X-ray at at least one point, preferably at at least two points, of the wall of the component.

3. The system according to Claim 1 or 2, wherein said at least one component is selected from pipe(s) and pipe connector(s).

4. The system according to any one of Claims 1 to 3, wherein said pipe connector is selected in the group comprising: adapter(s), elbow(s), coupling(s), union(s), reducer(s), tee(s), cross(es).

5. The system according to any one of the preceding Claims, wherein said PEEK comprises 100 mol% of units of formula (RPEEK):

6. The system according to any one of the preceding Claims, wherein said PEEK comprises 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% of units of formula (RPEEK):up to 1 mol%, up to 2 mol%, up to 5 mol%, up to 10 mol% or up to 15 mol% of at least one unit having formula (K-A) to (K-M):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.

7. The system according to any one of Claims 1 to 6, wherein said at least one component has a surface intended to be in contact with UPW, said surface being made from pellets [lubricated PEEK pellets] comprising PEEK and at least one lubricant adhered on at least an area of the external surface of said pellets.

8. The system according to Claim 7, wherein said lubricated PEEK pellets comprise PEEK in an amount of 100 wt.% based on the total weight of said pellets.

9. The system according to Claim 7, wherein said lubricated PEEK pellets comprise PEEK in an amount of at least 50 wt.%, more preferably at least 60 wt.%, 70 wt.%, 85 wt.%, 95 wt.%, 99.9 wt.% based on the total weight of said pellets, and at least one other polymer, preferably selected from polysulfone (PSU), polyphenylene sulfone (PPSLI), polyetherimide (PEI), one or more other polyarylether ketone (PAEK), in an amount from 0.1 wt.% to 5 wt.%, 15 wt.%, 30 wt.%, 40 wt.%, 50 wt.% based on the total weight of said pellets.

10. A method for manufacturing a component for transporting ultra pure water (UPW), said method comprising:(a) providing pellets comprising PEEK and at least one lubricant adhered on at least an area of the external surface of said pellets [lubricated PEEK pellets],(b) melting said lubricated PEEK pellets, thus providing melted pellets, and(c) forming said melted pellets into at least one component for transporting UPW.

11. The method according to Claim 10, wherein said lubricant is selected from calcium stearate, calcium palmitate, magnesium stearate, magnesium palmitate, zinc stearate or zinc palmitate.

12. The method according to Claim 10 or 11 , wherein step (c) of forming is performed by extrusion or injection moulding.

13. The method according to Claim 12, wherein step (c) is performed by extrusion and said PEEK 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.

14. The method according to Claim 13, wherein said component is selected from pipe(s).

15. The method according to Claim 12, wherein step (c) is performed by injection moulding and said PEEK has:- a number average molecular weight (Mn) 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 than110,000, 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.

16. The method according to Claim 15, wherein said component is selected from pipe connector(s).

17. The method according to any one of Claims 10 to 16, wherein said lubricated PEEK pellets:- have a diameter between 0.9 and 4.5 mm and / or a length between 1.5 and 4.8 mm; and / or- comprise said lubricant in an amount of from 25 to 500 ppm based on the amount of PEEK and PEEK in an amount of at least 50 mol% based on the total weight of said pellets.

18. A pipe for transporting ultra pure water (UPW) having a surface intended to be in contact with UPW, said pipe comprising a composition comprising PEEK and at least one metal selected from Ca, Mg and / or Zn in an amount from 5 to 20 ppm based on the amount of PEEK and as measured on said pipe by inductively coupled plasma coupled with optical emission spectroscopy (ICP-OES) after mineralization by ashing in a platinum crucible.

19. The pipe according to Claim 18, said pipe having a thickness variation of its wall of less than 20% from the nominal wall thickness, as measured via X-ray at at least one point of the wall of the pipe.

20. A pipe connector comprising a surface intended to be in contact with UPW, said pipe connector comprising a composition comprising PEEK and at least one metal selected from Ca, Mg and / or Zn in an amount from 5 to 20 ppm based on the amount of PEEK and as measured on said pipe connector by inductively coupled plasma coupled with optical emission spectroscopy (ICP-OES) after mineralization by ashing in a platinum crucible.

21. The pipe connector according to Claim 20, which has a thickness variation of its wall of less than 20% from the nominal wall thickness, as measured via X-ray at at least one point of the wall of the pipe connector.

22. Use of pellets comprising PEEK and at least one lubricant on at least an area of the external surface of said pellets, for the manufacture of a component for transporting UPW.

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