POLYMERS AND PROCESS FOR THEIR MANUFACTURE

Abstract

There is disclosed polymers, a process for manufacturing polymers and uses of the polymers. The polymers are polyaryl ether ketones and the process includes a nucleophilic polycondensation of a bisphenol with an organic dihalide compound in a reaction mixture comprising sodium carbonate and potassium carbonate, in an aromatic sulfone solvent, at a reaction temperature rising to a temperature from 290 C. to 320 C. immediately prior to the addition of a salt to the reaction mixture, wherein the molar ratio of the salt to potassium carbonate is from 6.0 to 10.0. Further organic dihalide compound is added to the reaction mixture wherein the molar ratio of further organic dihalide compound to bisphenol is from 0.009 to 0.035. The resulting reaction mixture is maintained at a temperature at from 290 C. to 320 C. for from 20 to 180 minutes and then the resulting reaction mixture is cooled and the PAEK recovered.

Claims

1. A process for producing polyaryletherketone, PAEK, the process comprising: a) nucleophilic polycondensation of a bisphenol with an organic dihalide compound in a reaction mixture comprising sodium carbonate and potassium carbonate, in an aromatic sulfone solvent, at a reaction temperature rising to a temperature from 290 C. to 320 C. immediately prior to; b) addition of a salt to the reaction mixture, wherein the molar ratio of the salt to potassium carbonate is from 6.0 to 10.0; c) addition of further organic dihalide compound to the reaction mixture, simultaneously with or subsequent to step b, wherein the molar ratio of further organic dihalide compound to bisphenol is from 0.009 to 0.035; d) maintenance of the resulting reaction mixture's temperature at from 290 C. to 320 C. for from 20 to 180 minutes; e) cooling of the resulting reaction mixture and recovery of the PAEK resulting from steps a to d from the reaction mixture; wherein in step a of the process: i) the molar ratio of sodium carbonate to bisphenol is from 0.95 to 1.15; ii) the molar ratio of potassium carbonate to sodium carbonate is from 0.0025 to 0.0040; and iii) the molar ratio of organic dihalide compound to bisphenol is from 1.005 to 1.010.

2. The process according to claim 1 wherein the aromatic sulfone solvent is diphenylsulfone.

3. The process according to claim 1 wherein the process is for producing a PAEK that is homopolymer polyetheretherketone; wherein the bisphenol is hydroquinone; and wherein the organic dihalide compound and the further organic dihalide compound are 4,4-difluorobenzophenone.

4. The process according to claim 1, wherein the salt is an alkali metal salt or an alkaline earth metal salt, and optionally, wherein the salt is selected from lithium chloride, calcium chloride, magnesium chloride, lithium bromide, lithium iodide and/or lithium sulphate.

5. The process according to claim 4 wherein the salt is lithium chloride or is lithium sulphate.

6. A polyaryletherketone, PAEK, comprising residual impurities of aromatic sulfone solvent, sodium salt and organic dihalide monomer from its formation by nucleophilic polycondensation; wherein when the PAEK is dissolved in concentrated sulfuric acid to prepare a resultant solution with 1 g of the PAEK per 100 ml of the resulting solution, the resultant solution has an absorbance contribution from the PAEK of less than 0.20 at a wavelength of light of 550 nm.

7. The PAEK according to claim 6 wherein the PAEK has a polydispersity index PDI=M.sub.W/M.sub.N, based on polystyrene equivalent molecular masses, of less than 2.5; wherein M.sub.w=weight average molecular mass and M.sub.n=number average molecular mass.

8. The PAEK according to claim 6 wherein when the PAEK is in the form of a sample with planar surface, injection moulded from the PAEK as a powder, the planar surface has: a lightness L* of greater than 65.0; an a* coordinate of greater than 0.2 but less than 5.0; a b* coordinate of greater than 5.0 but less than 12.0; with reference to the 1976 CIE L* a* b* colour space.

9. The PAEK according to claim 6, wherein the PAEK is homopolymer polyetheretherketone, PEEK, with repeat units consisting of formula II:
O-Ph-O-Ph-CO-Ph- II or a copolymer with repeat units consisting repeat units of formula II and repeat units of formula III:
O-Ph-Ph-O-Ph-CO-Ph- III.

10. The PAEK according to claim 6 wherein the PAEK is homopolymer PEEK.

11. The homopolymer PEEK according to claim 10 wherein the PEEK has an extractable concentration of 0.05 mg/kg or less of residual 4,4-difluorobenzophenone, when immersed in Miglyol 812 at 175 C. for six hours.

12. The homopolymer PEEK according to claim 10 wherein the residual impurities of aromatic sulfone solvent are present as 0.063% or less by weight in the PEEK, where said aromatic sulfone solvent is diphenylsulfone.

13. The homopolymer PEEK according to claim 10, wherein the PEEK has a critical strain energy release rate of at least 17.5 Jm.sup.2.

14.-20. (canceled)

21. A method for forming a pipe or sheath by extrusion of a composition comprising or consisting of PAEK according to claim 6.

22. The PAEK according to claim 6 wherein the PAEK is formed into (a) an enclosure for a portable electronic device, (b) a pipe or sheath, (c) a wire wrap, (d) a film, (e) a tape, or (f) a component intended to contact food.

23. The homopolymer PEEK according to claim 10 wherein the homopolymer PEEK is formed into (a) an enclosure for a portable electronic device, (b) a pipe or sheath, (c) a wire wrap, (d) a film, (e) a tape, or (f) a component intended to contact food.

Description

[0285] Specific embodiments of the invention will now be described, by way of example, and with reference to the accompanying figures in which:

[0286] FIG. 1 is a graph showing the absorbance at 550 nm of a solution of a number of inventive and comparative PEEKs as tested in accordance with Example 3;

[0287] FIG. 2 is a graph showing the PDI of a number of inventive and comparative PEEKs as tested in accordance with Example 4;

[0288] FIG. 3a is a graph showing the critical strain energy release of a number of inventive and comparative PEEKs as tested in accordance with Example 5;

[0289] FIG. 3b is a graph showing the stress intensity factor K.sub.1C of a number of inventive and comparative PEEKs as tested in accordance with Example 5;

[0290] FIG. 4 is a graph showing the lightness (L*) of a number of discs injection moulded from inventive and comparative PEEK powders as tested in accordance with Example 6;

[0291] FIG. 5 is a graph showing the lightness (L*) of granules of a number of inventive and comparative PEEKs as tested in accordance with Example 6; and

[0292] FIG. 6 is a graph showing the gel/black speck content of films extruded from a number of inventive and comparative PEEKs as tested in accordance with Example 7.

[0293] The following materials are referred to hereinafter:

[0294] PEEK-0.45-PPEEK powder having a Melt Viscosity of 0.45 kNsm.sup.2 at 400 C. obtained from Victrex Manufacturing Ltd.

[0295] PEEK-0.45-GPEEK granules having a Melt Viscosity of 0.45 kNsm.sup.2 at 400 C. obtained from Victrex Manufacturing Ltd.

[0296] PEEK-0.65-PPEEK powder having a Melt Viscosity of 0.65 kNsm.sup.2 at 400 C. obtained from Victrex Manufacturing Ltd.

[0297] PEEK-0.65-GPEEK granules having a Melt Viscosity of 0.65 kNsm.sup.2 at 400 C. obtained from Victrex Manufacturing Ltd.

[0298] KT810PKetaspire KT810P (TM) PEEK powder sold by Solvay.

[0299] KT820Ketaspire KT820 (TM) PEEK granules sold by Solvay.

[0300] L4000GVestakeep (TM) L4000G PEEK granules sold by Evonik Degussa.

[0301] 5000GVestakeep (TM) 5000G PEEK granules sold by Evonik Degussa.

[0302] The comparative PEEK samples made by Victrex Manufacturing Limited were made by a process equivalent to that disclosed in Example 3 of EP3049457A.

[0303] The comparative samples from the manufacturers Solvay and Evonik Degussa were made by their proprietary processes, the details of which are not known.

EXAMPLE 1

Preparation of Polvetheretherketone (PEEK)

[0304] The following describes the preparation of PEEK by a process according to the invention on a laboratory scale. 4,4-difluorobenzophenone (109.84 g, 0.504 mol), hydroquinone (55.06 g, 0.500 mol) and diphenyl sulfone (225.43 g, 1.033 mol) were weighed into a 0.5 L flask and subjected to an inert nitrogen atmosphere at room temperature overnight. Reactants were then heated to 150 C. During this time the reagents were stirred at 20 rpm for 20 minutes, prior to increasing stirrer speed to 70 rpm for the remainder of the reaction.

[0305] Sodium carbonate (54.59 g, 0.515 mol) and potassium carbonate (0.242 g, 1.75 mmol) were added to the reaction mixture over a two minute time period. The reaction temperature was increased to 312 C. at 1 C. min.sup.1. A temperature of 312 C. was maintained until the desired stirrer torque rise was observed.

[0306] At this point, lithium chloride (0.595 g, 0.014 mol) was added in one portion, and immediately afterwards, 4,4-difluorobenzophenone (2.18 g, 0.010 mol) was added in one portion in order to control molecular mass. After a further thirty minutes, the opaque off-white coloured crude product was discharged from the vessel onto a metal tray to cool and solidify.

[0307] Once cool, the crude product was milled into a coarse powder (<2 mm maximum dimension). The powder was suspended in acetone in a separating column, and washed with acetone to remove organic impurities, namely diphenyl sulfone solvent. Acetone 1 L) was slowly passed through the column until diphenyl sulfone solvent no longer precipitated out of organic wash on addition of water. The remaining product was then washed with cold deionised water to remove acetone 1 L), prior to hot deionised water 2 L) to remove aqueous by products. Once the conductivity of leachate was measured to be <2 S using a conductivity probe, the material remaining in the column was dried in an oven overnight, yielding an off-white powder product.

[0308] The process above was scaled up to plant scale (based on 386 kg of hydroquinone) in order to obtain 8 batches of PEEK of varying melt viscosities as shown in Table 1 below and as measured according to Example 2. In addition, a portion of five of the eight batches was melt filtered using a single screw extruder (screw speed of 90-110 rpm) and a 20 micrometre pore, 157 inch (17.8 cm) Capsule PEEK Filter Housing (available from Porvair Filtration Group Ltd). The melt filtration was carried out at a rate of 50 kg/hr with extruder barrel and die temperatures of 350-390 C. Upon extrusion the melt filtered material was cooled and chopped to obtain cylindrical granules of 2.0 to 3.5 mm diameter and 2.0 to 4.0 mm length.

EXAMPLE 2

Melt Viscosity of PEEKs

[0309] The Melt Viscosity of the PEEKs was measured using a ram extruder fitted with a tungsten carbide die, 0.5 mm (capillary diameter)3.175 mm (capillary length). Approximately 5 grams of the PAEK was dried in an air circulating oven for 3 hours at 150 C. The extruder was allowed to equilibrate to 400 C. The dried polymer was loaded into the heated barrel of the extruder, a brass tip (12 mm long9.920.01 mm diameter) placed on top of the polymer followed by the piston and the screw was manually turned until the proof ring of the pressure gauge just engages the piston to help remove any trapped air. The column of polymer was allowed to heat and melt over a period of at least 5 minutes. After the preheat stage the screw was set in motion so that the melted polymer was extruded through the die to form a thin fibre at a shear rate of 1000 s.sup.1, while recording the pressure (P) required to extrude the polymer. The Melt Viscosity is given by the formula

[00002]$\mathrm{Melt}.Math..Math.\mathrm{Viscosity}=\frac{P.Math..Math..Math..Math.r^4}{8.Math..Math.L.Math..Math.S.Math..Math.A}.Math.{\mathrm{kNsm}}^{-2}$ [0310] where P=Pressure/kN m.sup.2 [0311] L=Length of die/m [0312] S=ram speed/ms.sup.1 [0313] A=barrel cross-sectional area/m.sup.2 [0314] r=Die radius/m [0315] The relationship between shear rate and the other parameters is given by the equation:

[00003]$\text{Apparent wall shear rate}=1000.Math.s^{-1}=\frac{4.Math..Math.Q}{.Math..Math.r^3}$ [0316] where Q=volumetric flow rate/m.sup.3 s.sup.1=SA.

TABLE-US-00001 TABLE 1 Melt viscosities of PEEK batches prepared in accordance with the present invention. PEEK Batch MV (kNsm.sup.2) Batch 1 0.176 Batch 2 0.216 Batch 3 0.456 Batch 4 0.797 Batch 5 0.770 Batch 6 0.595 Batch 7 0.571 Batch 8 0.623

EXAMPLE 3

UV-Vis Absorbance of PEEKs

[0317] The extent of carbonyl branching in a number of PEEKs according to the present invention and comparative PEEKs was determined according to the following method. 1.0 g of PEEK was accurately weighed out and added to a 100 ml volumetric flask. PEEK powder samples and melt filtered granule samples, both according to the present invention, were tested. The comparative samples were all granule samples. Concentrated sulfuric acid (70 ml, specific gravity 1.84 g/ml at 25 C., 95-98 wt. %) was added to the flaskfor dissolution purposes (and to avoid the PEEK sticking in the neck of the flask) initially only three quarters of the volumetric flask was filled. The volumetric flask was capped and left on a shaker for around 18 to 30 hours (or, if using granules, until dissolved which was found to take as long as 2 to 4 days depending on the size of the granules). Once dissolved, the flask was filled to the 100 ml mark with further concentrated sulfuric acid and its contents were shaken to provide a resultant solution.

[0318] The absorbance arising from the dissolved polymer of the samples at 550 nm was then measured using a twin beam instrument such as a Jasco V-630 spectrophotometer fitted with USE-753 cell holder. The spectrophotometer settings were absorbance mode, a measurement range of 1000 nm to 400 nm, data Interval of 0.2 nm, a UV/Vis bandwidth of 1.5 nm, a scan speed of 100 nm/min and a halogen D2/WI light source.

[0319] The test solution was placed in a 10 mm quartz cuvette (ref. 100-QS) and concentrated sulfuric acid (specific gravity 1.84 g/ml at 25 C., 95-98 wt. %) placed in a separate 100-QS cell to act as a reference sample. The sample path length was 10 mm. After running a baseline spectrum with the cell holders empty, the cuvette containing the dissolved PEEK sample (resultant solution) was placed in the sample beam and the cuvette with the concentrated sulfuric acid sample was placed in the reference beam.

[0320] The light from the halogen lamp was focused and entered the monochromator, the light being dispersed by the grating in the monochromator and focused onto an exit slit. The light that passed through the exit slit was monochromated. The light was split into two beams, one going to the polymer solution to be measured and the other to the sulfuric acid reference sample. The light that passed through the reference and the polymer sample was incident on a silicon photodiode detector. The intensity of the light passing through the reference cell (lo) was measured for each wavelength of light passing through the spectrometer. Similarly, the intensity of the light passing through the sample cell (I) was also measured for each wavelength. Consequently, if the measured intensity of light passing through the sample cell (I) was less than the measured light passing through the reference sample (lo), the polymer sample had thereby absorbed a proportion of the light passing through the sample. This measured difference in the intensity of light passing through the polymer and reference sample was converted into a measure of absorbance, A.

[0321] The relationship between A and the intensity of light passing through the polymer sample (I) and the reference sample (lo) can be represented as:

[00004]$A={\log }_{10}.Math..Math.\frac{I_o}{I}$

[0322] The absorbance at light at a wavelength of 550 nm was measured from the resultant spectra output by the Jasco spectra Manager software.

[0323] The reference beam intensity after transmission through the reference is calibrated as 100% transmission or an absorbance measure of A=0, such that the value log.sub.10(T.sub.S/T.sub.R) for Absorbance corresponds solely to the contribution to absorbance from the dissolved polymer.

[0324] As explained above, the measured absorbance provides an indication of the level of carbonyl branching of the dissolved PAEK.

[0325] The measured absorbances are shown in Table 2 below and in FIG. 1.

TABLE-US-00002 TABLE 2 Extent of carbonyl branching in a number of inventive and comparative samples as shown by absorbance at 550 nm Sample/Batch Absorbance at 550 nm PEEK- 0.45-G 0.8132 PEEK-0.65-G 0.2075 5000G 0.2544 KT820 0.1747 L4000G 0.1695 Batch 1 (powder) 0.1102 Batch 2 (powder) 0.1306 Batch 3 (powder) 0.0905 Batch 4 (powder) 0.1040 Batch 4 (granules) 0.0989 Batch 5 (powder) 0.0845 Batch 5 (granules) 0.1006 Batch 6 (powder) 0.0733 Batch 6 (granules) 0.1026 Batch 7 (powder) 0.0682 Batch 7 (granules) 0.1031 Batch 8 (powder) 0.0834 Batch 8 (granules) 0.1192

[0326] As can be seen from Table 2 and FIG. 1, the PEEKs of the present invention absorb less light at a wavelength of 550 nm compared with the other PEEK samples measured. Therefore, PEEKs of the present invention have a lower level of carbonyl branching than the comparative samples tested i.e. the PEEKs of the present invention are substantially more straight-chained than the comparative PEEKs. This structural difference lends itself to a number of advantageous properties as shown below.

EXAMPLE 4

Molecular Mass Dispersity or Polydispersity Index (PDI) of PEEKs

[0327] The polydispersity of a number of samples was then tested as follows. Each sample solution was prepared by dissolving 40 mg of PEEK powder in 2 ml of 4-chlorophenol (PCP) at 205 C. The solution was then cooled, diluted to 20 ml with chloroform and filtered through a 0.45 m PTFE syringe filter before analysis.

[0328] Gel Permeation Chromotography Conditions:

[0329] Columns 2 Agilent PLGel Mixed B, 3007.8 mm

[0330] Solvent 10% w/v PCP in chloroform

[0331] Flow rate 1.0 ml/min

[0332] Temperature 35 C.

[0333] Detector Refractive index

[0334] The data was collected and analysed using Viscotek Omnisec 5.1 software. The system was calibrated using Agilent Easi Cal polystyrene standards. All molecular mass results reported are expressed as polystyrene equivalent molecular masses. The PDI values for batches 5-8 of the present invention and two comparative samples are shown below in Table 3 and in FIG. 2.

TABLE-US-00003 TABLE 3 PDI values for a number of inventive and comparative samples Sample/Batch PDI (Mw/Mn) PEEK-0.45-P 2.7 KT810 P 2.5 Batch 5 (powder) 2.2 Batch 6 (powder) 2.2 Batch 7 (powder) 2.1 Batch 8 (powder) 2.1

[0335] As is apparent from Table 3 and FIG. 2, the PEEKs of the present invention have a far lower dispersity (PDI), i.e. a far narrower distribution of molecular mass, in comparison with the comparative examples. Indeed, the PEEKs of the present invention exhibit PDIs that approach a PDI of 2.0.

EXAMPLE 5

Critical Strain Enemy Release Rate and Stress Intensity Factor of PEEKs

[0336] A standard test method for strain energy release rate (ASTM D 504599) was modified for use with test bars that could be produced in-house, to give a modified test method that was consistent with ductility behaviour in various applications. The modified test method uses energy release rate (per unit area) rather than stress-intensity as a measure of toughness.

[0337] Differences between ASTM test method D 5045-99 and modified test method:

[0338] Equipment

[0339] An ASTM flex support (51 mm span) and anvil were used rather than the Bending Rig shown in FIG. 1 of the ASTM test method. Test bars were tested using an Instron 5567 tensometer with 30kN load cell.

[0340] A loading-pin penetration and sample compression calibration (mentioned in 6.2.1 of the ASTM method) was not carried out.

[0341] A crosshead speed of 100 mm/min was used rather than the recommended 10 mm/min.

[0342] Sample Preparation

[0343] The test bars were slightly trapeze shaped rather than the specified rectangular prisms of the ASTM method. The test bars were injection moulded from powder and from granules in the case of the samples of the invention and from granules in the case of the comparative samples.

[0344] The sample size falls into the alternative specimens category described in A1.1.2it does not meet the specifications in 7.1.1. For the specimens tested W=12.7 mm, B=6.3 mm, a=4.7 mm.

[0345] The samples were machine notched as described in the ASTM method but no subsequent initiation of a natural crack was carried out (see 7.4.1 of the ASTM method).

[0346] Interpretation of Results

[0347] A graph of Flexure Extension (x-axis) versus Flexure Load (y-axis) was plotted.

[0348] The line AB mentioned in 9.1.1 of the ASTM method was not drawn as a best straight line but instead A was taken as the flexure extension result closest to a flexure load of 200 N, B was the flexure extension result closest to a flexure load of 300 N. A line was drawn between A and B which was extrapolated back to the x-axis and this point was labelled C. The line AB, described in the ASTM method, was not used.

[0349] Critical Strain Energy Release Rate (G.sub.lc) was determined directly from the energy derived from integration of the load versus displacement curve as described in 9.3 of the ASTM method however it was integrated from point C (described above) up to P.sub.max rather than up to P.sub.Q. The results are reported in Table 4a and in FIG. 3a in J/m.sup.2.

TABLE-US-00004 TABLE 4a Critical Strain Energy Release Rate of samples according to the present invention and comparative samples Critical Strain Energy Sample/Batch MV (kNsm.sup.2) Release Rate (J/m.sup.2) PEEK-0.45-G 0.436 8.27 KT820 0.598 15.08 Batch 6 (from powder) 0.622 18.27 Batch 6 (from granules) 0.622 18.27 Batch 8 (from powder) 0.636 18.03 Batch 8 (from granules) 0.636 18.03 PEEK-0.65-G 0.643 15.67 L4000G 0.646 14.55 5000G 0.708 16.74 Batch 5 (from powder) 0.770 18.69 Batch 5 (from granules) 0.770 19.25 Batch 4 (from powder) 0.797 18.35 Batch 4 (from granules) 0.797 18.89

[0350] It is well known to persons skilled in the art that fracture toughness increases with MV (and with molecular mass). Accordingly the data in Table 4a and in FIG. 3a has been presented in order of MV to show how the fracture toughness varies between materials of a similar MV. The data in Table 4a and FIG. 3a clearly show that for given MVs the PEEKs of the present invention demonstrate greater critical strain energy release rate, which is a measure of fracture toughness, than several comparative PEEKs. As detailed on page 1, a material with higher fracture toughness properties is particularly advantageous for use in thicker walled parts e.g. stock shapes including rods, machined components, extruded articles and in composites generally.

[0351] Stress Intensity factor K.sub.1C

[0352] The fracture toughness was measured using a test method as described in ISO17281:2002 on injection moulded granules of the present invention. The fracture toughness was determined by measuring of the stress intensity factor K.sub.1C which is identified as the point at which a thin crack in a material begins to grow.

TABLE-US-00005 TABLE 4b Measurement of stress intensity factor K.sub.1C Sample/Batch K.sub.1C(MPa .Math. m) KT820 4.784 PEEK-0.45-G 4.667 L4000G 4.940 Batch 5 (from granule) 5.067 Batch 8 (from granule) 5.002

[0353] Table 4b and FIG. 3b show that PEEKs of the present invention have a greater stress intensity factor K.sub.1C compared with other PEEKs. Therefore, PEEKs of the present invention have a high resistance to brittle fracture when a crack is present, and any propagation of a crack through the PEEK material of the present invention will undergo more ductile fracture.

[0354] As a result of this characteristic of the PEEK of the invention, the polymer is of particular use for the preparation of formed and moulded enclosures for electronic devices, particularly portable electronic devices which may be easily dropped, for instance portable smartphones and tablets.

[0355] For example, a casing for an electronic device form a composition comprising, substantially consisting of or consisting of PEEK of the present invention is provided. A casing for an electronic device includes an enclosure for a portable device such as a smart phone. The enclosure may be a moulded enclosure. Alternatively, the enclosure may be formed through an additive manufacturing process. An enclosure comprising, substantially consisting of or consisting PEEK of the present invention is particularly good at withstanding the stresses and strains of prolonged everyday use because the PEEK of the present invention has a high resistance to brittle fracture. Furthermore, enclosures comprising PEEK of the present invention are more able to withstand defects formed during manufacture of the enclosures, since small manufacturing defects can cause cracks that can propagate through the enclosures, and the PEEK of the present invention is more resistant to brittle fracture than other known PEEKs.

[0356] The composition of the casing may comprise from 30 to 100% of the PAEK or PEEK of the invention with from 0 to 70% by weight of other components such as filler, for instance fibrous filler, glass filler, colourants and the like. Preferably the composition of the casing comprises no other PAEK or PEEK, more preferably no other polymer.

EXAMPLE 6

Colour of PEEKs

[0357] The colour of inventive and comparative PEEKs was tested using Minolta CR400 and CR410 chromameters. Powder samples were first injection moulded into discs having a substantially flat surface for colour measurement using a 40t Engel Injection Moulder, and their colour evaluated using the Minolta CR400 chromameter. Granular samples had a granule size from 1 to 10 mm as determined by sieving and were placed into a granular materials attachment and their colour measured using the Minolta CR410 chromameter. Colour was measured in terms of L*, a* and b* values with reference to the 1976 CIE L* a* b* colour space.

[0358] Colour Evaluation of the Samples

[0359] Injection moulded discs from powder: For each disc, the measuring head was placed flat to the centre of the disc and a reading taken.

[0360] Granules: The granular materials attachment was inverted so that the granules were pressed against a glass window of the attachment when analysed. The granules filled the window and were stationary when a reading was taken. The measuring head was placed flat to the window when a reading was taken.

[0361] Discs Moulded from Powder:

[0362] A number of different samples of PEEK-0.45-P were measured in order to demonstrate the expected variability in the results

TABLE-US-00006 TABLE 5 Colour data for discs moulded from powder of inventive PAEKs and comparative PAEKs Disc Disc Disc MV Sample/Batch colour (L*) colour (a*) colour (b*) (kNsm.sup.2) PEEK-0.45-P 64.2 1.4 13.5 0.471 PEEK-0.45-P 64.9 1.2 11.8 0.448 PEEK-0.45-P 64.3 1.9 13.5 0.482 PEEK-0.45-P 65.6 2.5 10.1 0.483 PEEK-0.45-P 67.6 1.9 11.8 0.471 PEEK-0.45-P 65.2 1.2 15.6 0.454 PEEK-0.45-P 65.2 1.6 12.1 0.470 PEEK-0.45-P 65.7 1.7 11.6 0.492 PEEK-0.45-P 63.6 1.7 12.3 0.507 PEEK-0.45-P 63.2 1.9 12.3 0.531 PEEK-0.45-P 64.6 1.6 13.2 0.476 PEEK-0.45-P 65.7 1.5 12.6 0.441 PEEK-0.45-P 70.3 2.2 9.3 0.442 PEEK-0.45-P 66.5 1.7 11.9 0.508 Batch 1 75.7 1.2 8.8 0.176 (from powder) Batch 2 75.1 1.7 8.0 0.216 (from powder) Batch 3 71.8 2.0 8.9 0.456 (from powder) Batch 4 72.1 2.5 8.3 0.797 (from powder) Batch 5 71.4 2.3 9.5 0.770 (from powder) Batch 6 72.0 2.2 9.3 0.595 (from powder) Batch 7 75.3 3.0 7.2 0.571 (from powder) Batch 8 73.9 3.1 7.2 0.623 (from powder)

[0363] Granules:

TABLE-US-00007 TABLE 6 Colour data for granules of inventive PEEKs and comparative PEEKs Granule Granule Granule Sample/Batch colour (L*) colour (a*) colour (b*) L4000G 51.95 1.51 8.10 L4000G 50.34 1.51 7.56 L4000G 53.90 1.63 8.03 L4000G 52.97 1.62 3.98 L4000G 55.74 1.54 4.02 5000G 52.84 1.94 3.90 Batch 7 63.58 2.20 7.99 Batch 6 63.20 2.18 8.30 Batch 8 62.25 2.29 7.55 Batch 5 61.80 2.29 8.03 Batch 4 62.59 2.33 8.12

[0364] Tables 5 and 6 respectively show that the discs moulded from powder according to the present invention and the granules according to the present invention exhibit a* and b* values that are generally equivalent to those of the comparative samples. However, the L* values of the inventive samples are higher than those of the comparative samples, which means that overall the samples of the present invention appear lighter and whiter than the comparative PAEKs. The L* values for the discs moulded from powder and for the granules are also shown in FIGS. 4 and 5 respectively.

EXAMPLE 7

Gel/Black Speck Content of PEEKs

[0365] Gel/black speck content was assessed by a Brabender Film Quality Analyzer on amorphous extruded films prepared from inventive and comparative melt filtered powder. Extrusion conditions were:

[0366] Gravity fed, single screw 20 mm extruder set at 60 rpm

[0367] All heating zones set at 380 C.

[0368] Chill rollers set to 100 C.

[0369] Film speed set at 2.8 m/min.

[0370] The films were 100 micron thick and 45 to 50 mm wide.

[0371] Gels and black specks were detected by Brabender Film Quality Analyzer using a cold light source on a 1.2 m.sup.2 surface of film.

[0372] Gels are defined as defects with a transmittance of 25 to 70%.

[0373] Black specks are defined as defects with a transmittance of below 25%.

[0374] Transmittance of above 70% is defined as transparent.

[0375] Film defect results are expressed as a parts per million (ppm) count. By measuring the total number of pixels observed in a digital scan, and analysing how many pixels absorb light at a transmittance greater than the predefined transmittance as described above.

TABLE-US-00008 TABLE 7 Gel/black speck content of inventive and comparative samples Sample/Batch Gel/Black Speck Content (ppm) Film from PEEK-0.45-P 333 Film from PEEK-0.45-P 349 Film from PEEK-0.45-P 513 Film from PEEK-0.45-P 613 Film from PEEK-0.45-P 989 Film from PEEK-0.45-P 805 Film from PEEK-0.45-P 307 Film from PEEK-0.45-P 332 Film from Batch 5 110 Film from Batch 5 140 Film from Batch 6 170 Film from Batch 6 127 Film from Batch 7 119 Film from Batch 7 98 Film from Batch 8 79 Film from Batch 8 123

[0376] It will be immediately apparent from the values shown in Table 7 and in FIG. 6 that the PEEKs of the present invention have a far lower content of gels/black specks than the comparative PEEKs. This means that the PEEKs of the present invention are better suited for use in e.g. films and melt-spun fibres than the comparative PEEKs.

[0377] As a result of this characteristic of the PEEK of the invention, the polymer is of particular use for the preparation of polymeric film as there is a lower incidence of defects in the resultant films. PEEK of the invention improves the effective yield of good quality, defect-free polymer film, and hence decreases the amount of waste material.

EXAMPLE 8

Determination of Content of 4,4-Difluorobenzophenone in Miglyol Extracts

[0378] The level of extractable 4,4-difluorobenzophenone was measured using High-performance liquid chromatography (HPLC) on Miglyol 812 sample extracts. Samples of PEEKs were placed in a vessel of Miglyol 812 and the vessels were placed in an oven held at 175 C. The amount of residual 4,4-difluorobenzophenone extracted from each PEEK sample was measured by analysing the Miglyol 812 using HPLC.

[0379] The Miglyol 812 samples were analysed by HPLC with diode array detection using an Agilent 1260 HPLC system. The HPLC column was an Ascentis express ES-CN, having dimensions 150 mm3.0 mm and a particle size of 2.7 micrometres. Mobile phases comprised A=0.5% v/v acetic acid in water and B=0.5% v/v acetic acid in acetonitrile. The flow rate was set at 0.4 ml/minute. The run time was 26 minutes and the post equilibrium time was 15 minutes. The injection volume was 5 micro litres and the column temperature was 20 C. UV detection was set at 254 nm with a band width of 4 nm and the UV flow cell was 6 cm. The solvent gradient was as follows: at time (minutes)=0, A=95%, B=5%; at time (minutes)=5, A=95%, B=5%; at time (minutes)=20, A=30%, B=70%; at time (minutes)=21, A=0%, B=100%; at time (minutes)=25, A=0%, B=100%; and at Time (minutes)=26, A=95%, B=5%.

[0380] Miglyol 812 is a standard fatty food simulant used to monitor the amount of fat-extractable residues in polymers. A number of samples of PEEK were exposed via total immersion in 100 ml of Miglyol 812 and held at 175 C. Each PEEK sample had the following dimensions: 2.5 cm2.5 cm2 mm. A sample of the Mygliol 812 was analysed by HPLC to identify the amount of residual 4,4-difluorobenzophenone extracted from the PEEK sample into the Miglyol 812 sample after the PEEK sample had been immersed in the Miglyol 812 for six hours at 175 C.

TABLE-US-00009 TABLE 8 Measurements of extracted 4,4-difluorobenzophenone in Migylol 812 Amount of 4,4-difluorobenzophenone extracted from PEEK immersed in Migylol Sample/Batch extract after 6 hours at 175 C. KT820NT 0.173 mg/kg L4000G 0.090 mg/kg Batch 8 <0.04 mg/kg

[0381] Table 8 shows that the measured levels of 4,4-difluorobenzophenone extracted from the PEEK of the present invention into the Migylol 812 does not exceed regulatory levels of the specific migration of 4,4-difluorobenzophenone. The measured migration of 4,4-difluorobenzophenone, for PEEK of the present invention, was identified as less than 0.04 mg/kg of PEEK, and below the maximum allowed level specified in the European Commission Regulation (EU) No 10/2011 of 14 January 2011 on plastics materials and articles intended to come into contact with food when tested with Miglyol 812 at a high temperature of 175 C. under short term repeat use test conditions. Therefore, PEEK of the present invention has been found to be suitable for use in articles intended to come into contact with food.

[0382] As a result of this characteristic of the PEEK of the invention, the polymer is of particular use for the preparation of devices and components for use in the food industry, particularly components that come into direct contact with food such as components of coffee machines, blenders, mixers and other food preparation equipment or components thereof (such as liners, gears, filters, sieves, belting and extrusion nozzles and the like). As such, the invention provides a component for a machine for use in food and/or beverage preparation, wherein the component comprises PEEK of the present invention. The PEEK of the present invention is also particularly suitable for coating belts of conveyors used in the food industry for conveying food products.

EXAMPLE 9

Measurement of Residual Diphenylsulfone

[0383] Residual amounts of diphenylsulfone were assessed using a standard method for measuring total sulfur in light hydrocarbons, spark ignition engine fuel, diesel engine fuel, and engine oil by ultraviolet fluorescence (ASTM Standard D5453-16).

[0384] The test method measures the amount of sulfur dioxide in the materials tested. The measurement of the amount of sulfur dioxide enables the calculation of the amount of diphenylsulfone (DPS) in the materials.

TABLE-US-00010 TABLE 9 Levels of diphenylsulfone in PEEKs Sample/Batch Average diphenylsulfone by weight % KT820NT granule 0.064 L4000G granule 0.099 PEEK-0.45-G 0.132 Batch 9 granule 0.052 KT820NT powder 0.096 L4000G powder 0.098 PEEK-0.45-P 0.139 Batch 9 powder 0.063

[0385] Table 9 and FIG. 7 show that PEEK of the present invention has a lower average residual amount of diphenylsulfone expressed as an average weight percent relative to polymer.

[0386] Surprisingly, further leaching of the PEEKs was found to be ineffective at removal of further DPS. Without being bound by theory, the more linear PEEK polymer of the present invention is believed to crystallise more slowing so that the crystallites crystallise around any residual DPS resulting in a more porous powder from which more DPS can be leached.

EXAMPLE 10

Measurement of Pipe Strength

[0387] The strength of a pipe can be determined by measuring the burst pressure of the pipe. The pipe was made according to the Standard as recited in American Petroleum Institute API 17E Ed 4 (2010) which recites a specification for subsea umbilicals.

[0388] A simple test was carried out to determine the burst pressure of the pipe. First, a 1 m length of pipe of each sample was cut. The pipe had a nominal diameter of 15.6 mm. Then, suitable inserts and ferrules were swaged, using a swaging machine fitted with suitable inserts depending on the ferrule size, on to both ends of all of the pipes to make the test sample. Blanking caps were positioned on to one end of each test sample and were tightened. The test samples were then filled with water, avoiding air bubbles and a male hydraulic quick release fitting was attached to the other end of each test sample and fully tightened.

[0389] The test sample was then placed in to a pressure test tank and connected to a female quick release fitting. The test pressure was applied by slowly opening the valve on the test pump, such that the pressure increased gradually with a maximum pressure being achieved between 30 s & 60 s of starting the test.

[0390] The maximum test pressure achieved prior to pipe failure was recorded and is shown in Table 10.

TABLE-US-00011 TABLE 10 Measurement of pipe strength Sample Maximum burst pressure (Psi) PEEK-0.65 pipe 193.48 Batch 10 pipe 179.2

[0391] Surprisingly, pipe made from PEEK polymer of the present invention was found to have a higher burst strength when compared with pipe made from comparative polymer. The pipe made from PEEK polymer of the present invention had a 7% increase in the amount of pressure the pipe could withstand without failure. Therefore pipe made from PEEK polymer of the present invention is tougher and it follows that a thinner walled pipe of the present invention would give an equivalent burst strength to a thicker walled standard PEEK pipe.

[0392] The PEEKs of the present invention are particularly suited to a variety of different forms including film, pipes, tubing and wire coating and stock shapes. This is in part due to the reduced levels of residual stresses in the PEEK. The lower levels of branching found in PEEK of the present invention result in a more linear molecule which helps to reduce the residual stresses that may build up in the different forms. This is especially useful in pipes and tubing whereby residual stresses can cause the pipes and tubing to shatter when cut.

[0393] There is also disclosed a polymeric material comprising a polyaryletherketone (PAEK), wherein said PAEK has a polydispersity index (PDI) of less than 2.6, when measured in accordance with Example 4.

[0394] While it is known to those skilled in the art that the theoretical minimum PDI for step-growth polymerisation is 2.0, it has surprisingly been found that the PAEK of the present invention approaches this theoretical limit. PDI is a measure of the distribution of molecular mass in a given polymer sample and is calculated in accordance with the following equation:

PDI=Mw/Mn

[0395] where Mw=weight average molecular weight and [0396] Mn=number average molecular weight.

[0397] The PAEK demonstrates excellent mechanical and colour characteristics and has a lower frequency of gels in comparison with known PAEKs.

[0398] In an example, said PAEK has a polydispersity index (PDI) of less than 2.5, more preferably less than 2.4, even more preferably less than 2.3, most preferably less than 2.2, when measured in accordance with Example 4.

[0399] There is further provided a polymeric material comprising a polyaryletherketone (PAEK), wherein when said polymeric material is in the form of melt-filtered granules, said polymeric material has a lightness L* of greater than 56.0, an a* coordinate of greater than 1.3 but less than 5.0, and a b* coordinate of greater than 6.5 but less than 10.0, when measured in accordance with Example 6 and with reference to the 1976 CIE L* a* b* colour space.

[0400] It has surprisingly been found that the PAEK of the present invention is lighter and consequently appears whiter than known PAEKs. As detailed above, lighter/whiter PAEKs are useful because they enable ease of colour matching with similarly coloured components and their colour can be more easily adjusted.

[0401] Preferably said polymeric material has a lightness L* of greater than 58.0, more preferably greater than 59.0, even more preferably greater than 60.0, most preferably greater than 61.0.

[0402] Preferably said polymeric material has an a* coordinate of greater than 1.5 but less than 3.5, more preferably greater than 1.8 but less than 3.0, even more preferably greater than 2.0 but less than 2.5, most preferably greater than 2.1 but less than 2.4.

[0403] Preferably said polymeric material has a b* coordinate of greater than 6.7 but less than 9.0, more preferably greater than 7.0 but less than 8.7, even more preferably greater than 7.2 but less than 8.5, most preferably greater than 7.4 but less than 8.4.

[0404] In another example said polymeric material has a lightness L* of greater than 60.0, an a* coordinate of greater than 2.0 but less than 2.5, and a b* coordinate of greater than 7.2 but less than 8.5. In a more preferred embodiment said polymeric material has a lightness L* of greater than 61.0, an a* coordinate of greater than 2.1 but less than 2.4, and a b* coordinate of greater than 7.4 but less than 8.4.

[0405] There is also provided a polymeric material comprising a polyaryletherketone (PAEK), wherein when said polymeric material is in the form of an article injection moulded from a powder,

[0406] said polymeric material has a lightness L* of greater than 65.0, an a* coordinate of greater than 0.2 but less than 5.0, and a b* coordinate of greater than 5.0 but less than 12.0, when measured in accordance with Example 6 and with reference to the 1976 CIE L* a* b* colour space.

[0407] Preferably said article is a disc or a plaque.

[0408] Preferably said polymeric material has a lightness L* of greater than 67.0, more preferably greater than 69.0, even more preferably greater than 70.0, most preferably greater than 71.0.

[0409] Preferably said polymeric material has an a* coordinate of greater than 0.5 but less than 4.5, more preferably greater than 0.8 but less than 4.0, even more preferably greater than 1.0 but less than 3.5, most preferably greater than 1.1 but less than 3.2.

[0410] Preferably said polymeric material has a b* coordinate of greater than 5.5 but less than 11.0, more preferably greater than 6.0 but less than 10.5, even more preferably greater than 6.5 but less than 10.0, most preferably greater than 7.0 but less than 9.7.

[0411] In a preferred embodiment said polymeric material has a lightness L* of greater than 70.0, an a* coordinate of greater than 1.0 but less than 3.5, and a b* coordinate of greater than 6.5 but less than 10.0. In a more preferred embodiment said polymeric material has a lightness L* of greater than 71.0, an a* coordinate of greater than 1.1 but less than 3.2, and a b* coordinate of greater than 7.0 but less than 9.7.

[0412] The following are clauses relating to the disclosure.

[0413] 1. A polymeric material comprising a polyaryletherketone (PAEK),

[0414] wherein when said PAEK is dissolved in 1% w/v aqueous sulphuric acid to prepare a resultant solution, said resultant solution exhibits an absorbance of less than 0.20 at a wavelength of light of 550 nm, wherein said preparation of said resultant solution and measurement of its absorbance are carried out in accordance with Example 3.

[0415] 2. The polymeric material according to clause 1, wherein said resultant solution exhibits an absorbance of less than 0.18, preferably less than 0.16, more preferably less than 0.14, most preferably less than 0.12, at a wavelength of light of 550 nm when measured in accordance with Example 3.

[0416] 3. A polymeric material comprising a polyaryletherketone (PAEK),

[0417] wherein said PAEK has a polydispersity index (PDI) of less than 2.6, when measured in accordance with Example 4.

[0418] 4. The polymeric material according to clause 3, wherein said PAEK has a polydispersity index (PDI) of less than 2.5, preferably less than 2.4, more preferably less than 2.3, most preferably less than 2.2, when measured in accordance with Example 4.

[0419] 5. A polymeric material comprising a polyaryletherketone (PAEK),

[0420] wherein when said polymeric material is in the form of melt-filtered granules,

[0421] said polymeric material has a lightness L* of greater than 56.0, an a* coordinate of greater than 1.3 but less than 5.0, and a b* coordinate of greater than 6.5 but less than 10.0, when measured in accordance with Example 6 and with reference to the 1976 CIE L* a* b* colour space.

[0422] 6. The polymeric material according to clause 5, wherein said polymeric material has a lightness L* of greater than 60.0, an a* coordinate of greater than 2.0 but less than 2.5, and a b* coordinate of greater than 7.2 but less than 8.5.

[0423] 7. A polymeric material comprising a polyaryletherketone (PAEK),

[0424] wherein when said polymeric material is in the form of an article injection moulded from a powder,

[0425] said polymeric material has a lightness L* of greater than 65.0, an a* coordinate of greater than 0.2 but less than 5.0, and a b* coordinate of greater than 5.0 but less than 12.0, when measured in accordance with Example 6 and with reference to the 1976 CIE L* a* b* colour space.

[0426] 8. The polymeric material according to clause 7, wherein said polymeric material has a lightness L* of greater than 70.0, an a* coordinate of greater than 1.0 but less than 3.5, and a b* coordinate of greater than 6.5 but less than 10.0.

[0427] 9. The polymeric material according to any preceding clause, wherein said PAEK comprises a repeat unit of formula:

##STR00012##

[0428] wherein t1 and w1 independently represent 0 or 1 and v1 represents 0, 1 or 2.

[0429] 10. The polymeric material according to any preceding clause, wherein said PAEK is selected from polyetheretherketone and/or a copolymer including polyetheretherketone and polyetherdiphenyletherketone.

[0430] 11. The polymeric material according to any preceding clause, wherein said polymeric material has a critical strain energy release rate (as tested in accordance with example 5) of at least 17.5 Jm.sup.2, preferably at least 17.8 Jm.sup.2, more preferably at least 18.0 KJm.sup.2.

[0431] 12. The polymeric material according to any preceding clause, wherein said polymeric material further comprises one or more filler.

[0432] 13. A process for producing a polymeric material comprising a polyaryletherketone (PAEK), the process comprising the following steps:

[0433] a. polycondensing one or more bisphenol with one or more dihalobenzenoid compound, in the presence of

[0434] i. less than 0.005 molar ratio of potassium carbonate, and

[0435] ii. one or more carbonate of an alkali metal other than potassium carbonate, in a reactor; and

[0436] b. isolating the PAEK.

[0437] 14. The process according to clause 13, wherein step a of the process is carried out in the presence of less than 0.0045 molar ratio of potassium carbonate, preferably less than 0.0040 molar ratio of potassium carbonate, more preferably less than 0.0036 molar ratio of potassium carbonate, most preferably less than 0.0032 molar ratio of potassium carbonate.

[0438] 15. The process according to clause 13 or clause 14, wherein step a of the process is carried out in the presence of greater than 0.0001 molar ratio of potassium carbonate, preferably greater than 0.0010 molar ratio of potassium carbonate, more preferably greater than 0.0020 molar ratio of potassium carbonate, most preferably greater than 0.0025 molar ratio of potassium carbonate.

[0439] 16. The process according to any one of clauses 13 to 15, wherein said one or more carbonate of an alkali metal other than potassium carbonate comprises sodium carbonate.

[0440] 17. The process according to clause 16, wherein the molar ratio of sodium carbonate used in step a of the process is greater than 1.01, but less than 1.06.

[0441] 18. The process according to any one of clauses 13 to 17, wherein step a of the process is carried out in the presence of a salt A selected from lithium chloride, calcium chloride, magnesium chloride, lithium bromide, lithium iodide and/or lithium sulphate, preferably lithium chloride.

[0442] 19. The process according to clause 18, wherein the molar equivalents of salt A (relative to the moles of potassium carbonate present in step a of the process) is at least 1.0 molar equivalents, preferably at least 4.0 molar equivalents, more preferably at least 6.0 molar equivalents, most preferably at least 7.0 molar equivalents.

[0443] 20. The process according to any one of clauses 13 to 19, wherein step a of the process is carried out in the presence of a molar ratio of dihalobenzoid compound of at least 1.02, but at most 1.05.

[0444] 21. The process according to any one of clauses 13 to 20, wherein said one or more bisphenol comprises hydroquinone, 4,4-dihydroxpenzophenone and/or 4,4-dihydroxybiphenyl, and/or wherein said one or more dihalobenzenoid compound comprises 4,4-difluorobenzophenone.

[0445] 22. The process according to any one of clauses 13 to 21, wherein step a of the process is carried out at a temperature of from 100 C. to 390 C., preferably from 120 C. to 350 C., more preferably from 130 C. to 320 C.

[0446] 23. The process according to any one of clauses 13 to 22, wherein step a of the process is carried out at a temperature that increases to a maximum temperature of greater than 280 C., wherein in step a, after the maximum temperature is reached, said maximum temperature is maintained until a desired molecular weight of the PAEK has been reached, wherein once said desired molecular weight of the PAEK has been reached, one or more end-capping agent is added to the reactor.

[0447] 24. The process according to clause 23, wherein said end-capping agent is selected from one or more of a monohalobenzenoid compound such as 4-fluorobenzophenone or monochlorodiphenylsulphone, a dihalobenzenoid compound such as 4,4-difluorobenzophenone or dichlorodiphenylsulphone, methyl chloride and/or difluorodiketone, preferably selected from 4,4-difluorobenzophenone and/or 4-fluorobenzophenone.

[0448] 25. The process according to clause 23 or clause 24, wherein greater than 0.008 molar ratio, but less than 0.030 molar ratio of end-capping agent is added to the reactor.

[0449] 26. The process according to any one of clauses 13 to 25, wherein step a of the process comprises:

[0450] a. polycondensing one or more bisphenol with one or more dihalobenzenoid compound, in the presence of

[0451] i. greater than 0.0025 molar ratio but less than 0.0036 mole % of potassium carbonate, and

[0452] ii. greater than 1.01 molar ratio but less than 1.06 molar ratio of sodium carbonate, in a reactor;

[0453] wherein step a of the process is carried out in the presence of diphenylsulphone;

[0454] wherein step a of the process is carried out at a temperature of from 130 C. to 320 C., and is carried out at a temperature that increases to a maximum temperature of greater than 290 C. but less than 320 C.;

[0455] wherein prior to reaching said maximum temperature, greater than 1.005 molar ratio, but less than 1.010 molar ratio of said one or more dihalobenzenoid compound is brought into contact with said one or more bisphenol;

[0456] wherein after the maximum temperature is reached, said maximum temperature is maintained until a desired molecular weight of the PAEK has been reached;

[0457] wherein once said desired molecular weight of the PAEK has been reached, one or more end-capping agent is added to the reactor;

[0458] wherein greater than 0.009 molar ratio but less than 0.025 molar ratio of end-capping agent is added to the reactor;

[0459] wherein step a of the process is carried out in the presence of at least 6.0 molar equivalents but less than 10.0 molar equivalents of lithium chloride;

[0460] wherein said lithium chloride is added to the reactor once said desired molecular weight of the PAEK has been reached; and

[0461] wherein said lithium chloride is added to the reactor before said end-capping agent or at the same time as said end-capping agent.

[0462] 27. The process according to any one of clauses 13 to 26, wherein the process is for producing a polymeric material according to any one of clauses 1 to 12.

[0463] 28. The polymeric material according to any one of clauses 1 to 12, wherein said polymeric material is obtainable by or obtained by the process according to any one of clauses 13 to 27.

[0464] 29. An article which comprises a polymeric material according to any one of clauses 1 to 12 or 28 or a polymeric material made in the process of any one of clauses 13 to 27.

[0465] 30. The article according to clause 29, wherein said article is a film, and wherein said film has a gel/black speck level of less than 300 ppm, preferably less than 250 ppm, more preferably less than 200 ppm, even more preferably less than 180 ppm, when measured in accordance with Example 7.

[0466] 31. Use of the process according to any one of clauses 13 to 27 to provide a PAEK with an increased lightness L*, when measured in accordance with Example 6 and with reference to the 1976 CIE L* a* b* colour space.

[0467] Attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

[0468] All of the features disclosed in this specification (including any accompanying claims and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

[0469] Each feature disclosed in this specification (including any accompanying claims, and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

[0470] The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.