High melt flow PAEK compositions

Abstract

A composition [composition (C)] comprising: from 0.1 to 99.8% by weight (wt. %) of at least one poly(aryl ether ketone) polymer having a melt flow rate (MFR) equal to or higher than 8 g/10 min at 400 C. and under a load of 2.16 kg, as measured in accordance with ASTM method D1238 [(PAEK.sub.HMF) polymer], from 0.1 to 30 wt. % of at least one poly(tetrafluoroethylene)polymer having a D50 particle size equal to or below 10 m, and having a melting temperature equal to or below 324 C. [(PTFE) polymer], and from 0.1 to 30% wt. % of at least one carbon fiber, and wherein all % are based on the total weight of the composition (C).

Claims

1. A composition (C) comprising: a. from 20 to 80% by weight (wt. %) of at least one poly(aryl ether ketone) polymer, (PAEK.sub.HMF) polymer, having a melt flow rate (MFR) from 15 g/10 min to 80 g/10 min at 400 C. and under a load of 2.16 kg, as measured in accordance with ASTM method D1238; b. from 12 to 30 wt. % of at least one poly(tetrafluoroethylene) polymer, (PTFE) polymer, having a D50 particle size from 2 to 8 m, and having a melting temperature (T.sub.mII) from 321 C. to about 324 C.; and c. from 10 to 30 wt. % of at least one carbon fiber, and wherein all wt. % are based on a total weight of the composition (C).

2. The composition (C) according to claim 1, wherein more than 50% moles of recurring units of the (PAEK.sub.HMF) polymer are recurring units (R.sub.PAEK_HMF) selected from the group consisting of formulae (J-A) to (J-O): ##STR00006## ##STR00007## wherein: each of R, equal to or different from each other, is selected from the group consisting of halogen, alkyl, alkenyl, alkynyl, aryl, ether, thioether, carboxylic acid, ester, amide, imide, alkali or alkaline earth metal sulfonate, alkyl sulfonate, alkali or alkaline earth metal phosphonate, alkyl phosphonate, amine and quaternary ammonium; and j is zero or is an integer from 0 to 4.

3. The composition (C) according to claim 2, wherein the (PAEK.sub.HMF) polymer is a polyetheretherketone polymer, (PEEK.sub.HMF) polymer, and the (PAEK.sub.HMF) polymer comprises more than 50 wt. % of recurring units (R.sub.PAEK_HMF) of formula J-A. ##STR00008##

4. The composition (C) according to claim 1 comprising from 55 to 75 wt. % of the (PAEK.sub.HMF) polymer, based on a total weight of the composition (C).

5. The composition (C) according to claim 1, wherein the melt flow rate (MFR) of the (PAEK.sub.HMF) polymer is from 38 g/10 min to 45 g/10 min at 400 C. and under a load of 2.16 kg, as measured in accordance with ASTM method D1238.

6. The composition (C) according to claim 1, wherein the (PTFE) polymer has a D50 particle size from 3 m to 7 m.

7. The composition (C) according to claim 1, wherein the carbon fiber is selected from the group of PAN-based carbon fibers (PAN-CF), pitch based carbon fibers, graphitized pitch-based carbon fibers, and mixtures thereof.

8. The composition (C) according to claim 7, wherein the carbon fiber is a PAN-based carbon fiber.

9. The composition (C) according to claim 1 comprising from 10 to 20 wt. % of the carbon fiber, based on a total weight of the composition (C).

10. A process for manufacturing the polymer composition (C) according to claim 1, the process comprises mixing: d. the at least one (PAEK.sub.HMF) polymer; e. the at least one (PTFE) polymer; f. the at least one carbon fiber; and g. optionally, at least one other ingredient (I).

11. The process according to claim 10 comprising mixing the (PAEK.sub.HMF) polymer, the (PTFE) polymer, the carbon fiber, and optionally, the other ingredients (I) by dry blending and/or melt compounding.

12. The process according to claim 10, wherein the (PAEK.sub.HMF) polymer, the (PTFE) polymer, the carbon fiber, and optionally, the other ingredients (I) are melt compounded in continuous or batch devices.

13. An article comprising the composition (C) according to claim 1.

14. The article according to claim 13, wherein the article is a bearing article.

15. A process for manufacturing an article comprising at least one step of injection moulding, extrusion moulding, blow moulding, foam processing, compression molding, casting and coating the composition (C) according to claim 1.

16. The composition (C) according to claim 1, wherein the D50 particle size is measured by dynamic or laser light scattering techniques or using screen analysis according to DIN 53196.

17. The composition (C) according to claim 1, wherein the (PTFE) polymer has a number average molecular weight (Mn) equal to or below 200,000.

18. The composition (C) according to claim 1, wherein the (PTFE) polymer has a number average molecular weight (Mn) equal to or below 20,000.

Description

EXAMPLES

(1) The invention will be now described in more details with reference to the following examples, whose purpose is merely illustrative and not intended to limit the scope of the invention.

(2) Raw Materials

(3) KETASPIRE KT-880 [MFR (400 C./2.16 kg) is 39.5 g/10 min; MV (400 C., 1000 s-1) is 0.15 kPa.Math.s; IV is 0.75 dl/g-0.77 dl/g] is an aromatic polyetheretherketone (PEEK) polymers commercially available from Solvay Specialty Polymers USA, LLC.

(4) PEEK polymer blend containing 50 wt. % KETASPIRE KT-880 polymer and 50 wt. % KETASPIRE KT-820 polymer relative to total weight of PEEK polymer blend [MFR (400 C./2.16 kg) is 22.8 g/10 min].

(5) PTFE: Polymist XPP-511 is a polytetrafluoroethylene powdered resin, obtained from SOLVAY SPECIALTY POLYMERS ITALY S.p.A. having a D50 particle size of 20 m, a melting point T.sub.m(II) of 329 C. The melt viscosity (MV) is equal to or lower than 110.sup.5 Pa.Math.s at 372 C. measured according to a modified ASTM D1238-52T method.
PTFE: Algoflon L203 is a polytetrafluoroethylene powdered resin, obtained from SOLVAY SPECIALTY POLYMERS ITALY S.p.A. having a D50 particle size of 6 m, a melting point T.sub.m(II) of 328 C. The melt viscosity (MV) is equal to or lower than 110.sup.5 Pa.Math.s at 372 C. measured according to a modified ASTM D1238-52T method.
PTFE: Polymist F5-A is a polytetrafluoroethylene powdered resin, obtained from SOLVAY SPECIALTY POLYMERS ITALY S.p.A. having a D50 particle size of 4 m, a melting point T.sub.m(II) of 326 C. The melt viscosity (MV) is equal to or lower than 110.sup.5 Pa.Math.s at 372 C. measured according to a modified ASTM D1238-52T method.
PTFE: 3M Dyneon J14 is a polytetrafluoroethylene powdered resin, obtained from 3M Dyneon, average particle size is 6 m, a melting point T.sub.m(II) of 321 C. The melt viscosity (MV) is equal to or lower than 110.sup.5 Pa.Math.s at 372 C. measured according to a modified ASTM D1238-52T method.
Carbon fiber: PAN-CF; Chopped, obtained as SIGRAFIL C30 006 APS from SGL Carbon Fibers Ltd., length 3-6 mm.
The Following Characterizations Carried Out on the Materials of the Examples are Indicated Hereinafter:
Melt Flow Rate (MFR)

(6) The melt flow rate (MFR) of the (PTFE) polymer is measured at 372 C. and under a load of 10 kg and of the PEEK polymer at 400 C. and under a load of 2.16 kg, both in accordance with ASTM method D1238.

(7) The melt flow rate (MFR) of polymer composition is measured at 400 C. and under a load of 5 kg, in accordance with ASTM method D1238.

(8) Viscosity Measurements

(9) The melt viscosity (MV) of the (PTFE) polymer is measured at 372 C. in accordance with the procedure ASTM D-1238-52T modified as notably described in U.S. Pat. No. 4,380,618: the cylinder, orifice and piston tip are made of a corrosion-resistant alloy, Haynes Stellite 19, made by Haynes Stellite Co. The 5.0 g sample is charged to the 9.53 mm (0.375 inch) inside diameter cylinder, which is maintained at 372 C. Five minutes after the sample is charged to the cylinder, it is extruded through a 2.10 mm (0.0825 inch) diameter, 8.00 mm (0.315 inch) long square-edge orifice under a load (piston plus weight) of 5000 grams. This corresponds to a shear stress of 44.8 KPa (6.5 pounds per square inch). The melt viscosity in poises is calculated as 53170 divided by the observed extrusion rate in grams per minute.

(10) Melt viscosity (MV) measurements of PEEK polymers were made with a capillary rheometer according to ASTM D3835. Readings were taken at 400 C. using a die with the following characteristics: diameter: 1.016 mm, length: 20.32 mm, cone angle 120 and a shear rate of 1000 s.sup.1.

(11) The viscosity of a melt of KETASPIRE KT-880 PEEK polymers was also measured as a function of shear rate at several temperatures using an LCR-7000 Capillary Rheometer and using a die with the following characteristics: diameter: 1.016 mm, length: 20.32 mm, cone angle 120, as shown in Table 1 below:

(12) TABLE-US-00001 TABLE 1 Shear Rate (1/s) Visc. (kPa .Math. s) at 400 C. 100.2 0.225 400.9 0.187 1002.3 0.154 2505.7 0.121 5011.5 0.960 7015.9 0.850 10022.8 0.710

(13) Reduced viscosity (RV) of the PEEK polymers were measured in 95-98% sulfuric acid (d=1.84 g/ml) at a polymer concentration of 1 g/100 ml at 25 C. using a Cannon-Fenske viscometer tube (No. 50) according to ASTM D2857.

(14) Intrinsic viscosity (IV) of the PEEK polymers were measured in 95-98% sulfuric acid (d=1.84 g/ml) at a polymer concentration of 0.1 g/100 ml at 25 C. using a Cannon-Fenske viscometer tube (No. 50) according to ASTM D2857.

(15) The second melting temperature (T.sub.m(II) melting point)

(16) The second melting temperature was measured according to the ASTM D3418 method which has been modified in such a way that the heating and cooling steps are carried out as shown in Table 1 below:

(17) TABLE-US-00002 TABLE 1 Step # 1 Heat to 250 C. at 50 C./minute 2 Heat from 250 C. to 380 C. at 10 C./minute 3 Hold for 2 minutes 4 Cool from 380 C. to 250 C. at 10 C./minute 5 Hold for 2 minutes 6 Heat from 250 C. to 380 C. at 10 C./minute 7 Hold for 2 minutes 8 Cool down

(18) The melting point observed at the second heating period was recorded and is hereby referred to as the melting point of the (PTFE) polymer (T.sub.m(II))

(19) Mechanical Properties

(20) The mechanical properties of the PEEK/PTFE/CF polymer compositions prepared were tested according to ISO standards using the type 1A (ISO 3167) test specimens.

(21) The various ISO tests employed were the following: Flexural Strength and Modulus: ISO178 Tensile Strength and Modulus: ISO 527 Notched Izod Impact: ISO 180 The mechanical properties are summarized in Table 2
Friction and Wear Behavior

(22) The friction and wear behavior of the samples were evaluated according to the GM plastic material specification test, in particular per the sequence B protocol (high speed and low pressure) of the wear test GMW16771, by using a Tribometer, incorporated herein by reference in its entirety. The testing was carried out after break-in by running each step in the order as specified in the specification test. The duration at each step was 5 minutes at the specified load and speed followed by stopping for 30 minutes before going to the next test step. The test specimens consisted of three 0.250.250.13 square pins located 120 apart on a 0.938 mean sample diameter circle and the mating surface was a standard ASTM washer per ASTM D3702 standard.

(23) The wear testing involved the study of the limiting pressure and velocity (PV-limit, psi.Math.ft/min) values of the test specimen, as described above. The PV limit values are summarized in Table 2.

(24) The load and velocity bearing capability of the polymer composition may be expressed as that combination of load and speed at which the coefficient of friction or the interface temperature of a bearing surface fails to stabilize. As used herein, the term PV limit will be used to denote the pressure-velocity relationship determined by the combination of load and speed at which the coefficient of friction (COF, ) or the interface temperature of the tensile bar surface fails to stabilize, expressed by the product of the unit pressure P (psi) based upon the contact area and the linear velocity V or speed (ft/min);(psi.Math.ft/min).

(25) General Description of the Compounding Process of the PEEK/PTFE/CF Polymer Compositions

(26) A dry blend of PEEK polymer with the desired amounts of PTFE polymer was first prepared by tumble blending. The pre-blended mixture was then fed into the main hopper (barrel 1) of a Berstorff 25 mm twin screw extruder. The desired amounts of carbon fiber (CF) were fed gravimetrically into side-feeder 1 fixed at barrel 5. The extruder had an L/D ratio of 44 and a total of 8 barrel sections and a vacuum vent located at barrel section 7. The extrudate was cut into pellets for molding.

(27) Standard Type 1A (ISO 3167) test specimen bars were injection molded and used for all mechanical and friction and wear testing. All samples requiring specimen sizes different from type 1A bars were cut to the desired size specified by the test.

(28) Composition of the different polymer compositions are summarized in tables 2 and 4.

(29) TABLE-US-00003 TABLE 2 Polymer Examples No composition C1 C2 C3 4 C5 6 Polymer KETASPIRE 70 70 70 70 composition KT-880 PEEK polymer (wt. %) PEEK polymer 70 70 blend .sup.(a) (wt. %) Algoflon 15 15 L203 PTFE (wt. %) Polymist 15 XPP-511 PTFE (wt. %) Polymist 15 F5-A PTFE (wt. %) 3M.sup. Dyneon.sup. 15 15 J14 PTFE (wt. %) Carbon fiber 15 15 15 15 15 15 (wt. %) Pan-CF PTFE T.sub.m(II) melting 329 328 326 321 329 321 properties point ( C.) D50 particle size 6 20 4 6 6 6 (m) Polymer MFR 33 36 47 64 13 21 composition [400 C./5 kg] properties (g/10 min) PV limit 225,000 233,333 266,667 350,000 283,333 383,333 (psi .Math. ft/min) Flexural 241 243 256 255 Strength (MPa) Flexural 12200 12600 13000 13400 Modulus (MPa) Tensile Strength 170 175 176 177 (MPa) Tensile Modulus 16100 15700 15600 16400 (MPa) Notched Izod 6.49 6.41 6.65 7.01 Impact (KJ/m.sup.2) .sup.(a) PEEK polymer blend containing 50 wt. % KETASPIRE KT-880 polymer and 50 wt. % KETASPIRE KT-820 polymer relative to total weight of PEEK polymer blend [MFR (400 C./2.16 kg) is 22.8 g/10 min]

(30) The extrusion conditions are summarized in table 3.

(31) TABLE-US-00004 TABLE 3 Screw Diameter: 25 mm Screw Speed: 180 rpm L/D = 44 Zone Name T.sub.Barrel [ C.] 1 Barrel 1 30 2 Barrel 2 320 3 Barrel 3 320 4 Barrel 4 330 5 Barrel 5 330 6 Barrel 6 330 7 Barrel 7 340 8 Barrel 8 340 9 Adapter 340 10 Die plate 340

(32) TABLE-US-00005 TABLE 4 Polymer Examples No composition C7 8 C9 10 C11 12 Polymer KETASPIRE 80 80 55 55 65 65 composition KT-880 PEEK polymer (wt. %) Algoflon 10 15 25 L203 PTFE (wt. %) 3M 10 15 25 Dyneon J14 PTFE (wt. %) Carbon fiber 10 10 30 30 10 10 (wt. %) Pan-CF PTFE T.sub.m(II) melting 329 321 329 321 329 321 properties point ( C.) D50 particle 6 6 6 6 6 6 size (m) Polymer MFR 42 57 16 25 30 88 composition [400 C./5 kg] properties (g/10 min) PV limit 250,000 366,667 250,000 300,000 233,333 383,333 (psi .Math. ft/min)