POLYMERIC MATERIALS

Abstract

A component comprises a first part and a second part, wherein said second part is in contact with said first part, wherein: (i) said first part comprises a polymer having a repeat unit of formula

O-Ph-O-Ph-CO-Ph-I and a repeat unit of formula

O-Ph-Ph-O-Ph-CO-PhII wherein Ph represents a phenylene moiety; and (ii) said second part comprises a metal.

Claims

1. A component comprising a first part and a second part, wherein said second part is in contact with said first part, wherein: (i) said first part comprises a polymer having a repeat unit of formula
O-Ph-O-Ph-CO-Ph-I and a repeat unit of formula
O-Ph-Ph-O-Ph-CO-Ph-II wherein Ph represents a phenylene moiety; and (ii) said second part comprises a metal.

2. A component according to claim 1, wherein said second part comprises a metal selected from aluminium and steel.

3. A component according to claim 1, wherein said second part comprises aluminium.

4. A component according to claim 1, wherein said polymer is in contact with less than 95% of the total surface area of the second part.

5. A component according to claim 1, wherein said repeat units I and II are in the relative molar proportions I:II of from 65:35 to 95:5.

6. A component according to claim 1, wherein, in said polymer, the following relationship applies:
log.sub.10(X %)>1.500.26 MV; wherein X % refers to the % crystallinity measured as described in Example 22 and MV refers to the melt viscosity measured using capillary rheometry operating at 340 C. at a shear rate of 1000 s.sup.1 using a circular cross-section tungsten carbide die, 0.5 mm (capillary diameter)3.175 mm (capillary length).

7. A component according to claim 1, wherein said repeat unit of formula I has the structure: ##STR00003## and said repeat unit of formula II has the structure: ##STR00004##

8. A component according to claim 1, wherein said polymer includes 68-82 mol % (eg 72-77 mol %) of units of formula III and 18-32 mol % (e.g. 23-28 mol %) of units of formula IV.

9. A component according to claim 1, wherein the sum of the mol % of units of formula III and IV in said polymer is at least 95 mol % and the ratio defined as the mol % of the units of formula III divided by the mol % of units of formula IV is in the range 1.8 to 5.6.

10. A component according to claim 1, wherein the Tm of said polymer is in the range 290-310 C.

11. A component according to claim 1, wherein said polymer is part of a composition which includes said polymer and a filler.

12. A component according to claim 11, wherein said filler is selected from glass fibre, carbon fibre, aramid fibres, carbon black and a fluorocarbon resin and, preferably, is glass fibre.

13. A component according to claim 11, wherein said composition includes greater than 10 wt % of filler.

14. A component according to claim 1, wherein the force needed to separate the first and second parts is greater than the force that would be required to separate the same first and second parts if there was only a mechanical interaction between the first and second parts.

15. A component according to claim 1, wherein the area of the first part in contact with the second part is at least 1 cm.sup.2; the thickness of the first part measured perpendicular to the interface between the first and second parts is at least 1 mm and is less than 20 mm; and the thickness of the second part measured perpendicular to the interface between the first and second parts is at least 1 mm and less than 20 mm.

16. A component according to claim 1, wherein said first part overlies said second part and preferably comprises an over-moulded region on said second part.

17. A component according to claim 1, wherein said component is part of a mobile electronics device, for example, a device for connection to the worldwide web or for communications.

18. A method of making a component, the method comprising: (a) selecting a second part comprising a metal; (b) selecting a first part comprising a polymer or selecting a precursor of said first part which comprises said polymer, wherein said first part comprises a polymer having a repeat unit of formula
O-Ph-O-Ph-CO-Ph-I and a repeat unit of formula
O-Ph-Ph-O-Ph-CO-Ph-II wherein Ph represents a phenylene moiety; and; (c) contacting said second part with said first part or said precursor.

19. (canceled)

20. A method according claim 18, wherein, prior to step (c), said second part is treated to alter its surface with which said first part or precursor is subsequently contacted.

21. A method according to claim 20, wherein said treatment comprises a step which comprises treating the second part with an oxidizing formulation which includes a Fe.sup.3+ compound.

22. A component according to claim 1, wherein said second part comprises titanium.

Description

EXAMPLE 1Preparation of Polyetheretherketone (PEEK)-Polyetherdiphenyletherketone (PEDEK) Copolymer

[0088] A 300 litre vessel fitted with a lid, stirrer/stirrer guide, nitrogen inlet and outlet was charged with diphenylsulphone (125.52 kg) and heated to 150 C. Once fully melted 4,4-diflurobenzophenone (44.82 kg, 205.4 mol), 1,4-dihydroxybenzene (16.518 kg, 150 mol) and 4,4-dihydroxydiphenyl (9.311 kg, 50 mol) were charged to the vessel. The contents were then heated to 160 C. While maintaining a nitrogen blanket, dried sodium carbonate (21.368 kg, 201.6 mol) and potassium carbonate (1.106 kg, 8 mol), both sieved through a screen with a mesh of 500 micrometres, were added. The D50 of the sodium carbonate was 98.7 m. The temperature was raised to 180 C. at 1 C./min and held for 100 minutes. The temperature was raised to 200 C. at 1 C./min and held for 20 minutes. The temperature was raised to 305 C. at 1 C./min and held until desired melt viscosity was reached, as determined by the torque rise of the stirrer. The required torque rise was determined from a calibration graph of torque rise versus MV. The reaction mixture was poured via a band caster into a water bath, allowed to cool, milled and washed with acetone and water. The resulting polymer powder was dried in a tumble dryer until the contents temperature measured 112 C.

[0089] The following treatments are referred to hereinafter.

[0090] Metal samples were degreased by wiping with acetone.

Treatment 1Flame Treatment

[0091] This involved skimming a naked flame over the surface of metal samples.

Treatment 2Shot-Blasting

[0092] Metal samples were grit blasted with virgin white aluminium oxide for several minutes ensuring that the surface was evenly roughened.

Treatment 3Etching Method 1

[0093] Metal foil strips (75 mm200 mm) of gauge 0.125 m were wiped with acetone. Concentrated sulphuric acid (270 ml) and 30% nitric acid (85 ml) were added slowly with stirring to 1.5 L of deionised water. The solution was maintained at a temperature of 60-65 C. and the metal foil strips were immersed in it for 30 minutes before being washed with deionised water and dried in a stream of hot air. Preparation of test samples subsequently takes place within two hours.

Treatment 4Etching Method 2

[0094] Metal foil strips (75 mm200 mm) of gauge 0.125 m were wiped with acetone. Concentrated sulphuric acid 98.5% (270 ml) and 30% nitric acid (85 ml) were added slowly with stirring to 1.5 L of deionised water and the solution was maintained at a temperature of 60-65 C. Ferric sulphate (122.5 g, 0.3 mol) was dissolved in 185 ml of concentrated 98.5% sulphuric acid and added slowly with stirring to 1 L of deionised water; and the solution was maintained at a temperature of 60-65 C. Metal foil strips were immersed in the sulphuric/nitric acid solution for 30 minutes before being washed with deionised water and dried in a stream of hot air. They were again wiped with acetone and then immersed in the ferric sulphate solution for 8 minutes before being washed with deionised water and dried in an air circulating oven at 110 C. The foil strips were stored in a desiccator until bonded. Preparation of test samples subsequently takes place within two hours.

[0095] The following test procedure was used.

EXAMPLE 2Preparation of Test Samples

[0096] Dry polymer (7 g) was melted and compression moulded at 400 C. and 5 tonnes for 2 minutes then quenched in cold water producing an amorphous film of thickness 0.2-0.3 mm. The film was cut into 75 mm150 mm strips. A strip of polymer film was sandwiched between two metal foil strips (75 mm200 mm) treated by one of treatments 1 to 5 to produce a laminate. The laminate was then heated to 400 C. in the press to melt the polymer before being quenched into cold water, producing a test sample comprising two strips of foil bonded together by polymer; this sample was cut into 3 equal strips (25 mm200 mm) for testing by a T-peel test, as described in Example 3.

EXAMPLE 3T-Peel Test

[0097] The adhesive bond strength of the samples prepared as previously described was tested according to ISO 113399 on an Instron 2736-015 tensile testing machine operating with a 30 KN load cell using a T-peel test with a peel rate of 50 mm/minute and a peel extension of 200 mm.

Results

[0098] Data generated from the T-peel test from triplicate samples was averaged and the results reported in Table 1.

Note: In the table, C designates a comparative example.

TABLE-US-00001 TABLE 1 Treatment Polymer Method Example No. Metal Composition Treatment No. Force (N) 4 Aluminium B 1 3.113 5 Aluminium B 2 15.948 6 Aluminium B 3 10.759 7 Aluminium B 4 45.785 8 Aluminium C 1 47.705 9 Aluminium C 2 49.927 10 Aluminium C 3 49.569 11 Aluminium C 4 54.364 12 Aluminium F 1 12.731 13 Aluminium F 2 39.373 14 Aluminium F 3 20.524 15 Aluminium F 4 35.451 C4 Aluminium A 1 2.099 C5 Aluminium A 2 5.409 C6 Aluminium A 3 2.936 C7 Aluminium A 4 21.183 C8 Aluminium D 1 13.632 C9 Aluminium D 2 41.805 C10 Aluminium D 3 26.558 C11 Aluminium D 4 37.655 C12 Aluminium E 1 5.632 C13 Aluminium E 2 35.597 C14 Aluminium E 3 8.921 C15 Aluminium E 4 13.535 16 Stainless Steel F 1 28.664 17 Stainless Steel F 3 46.757 C16 Stainless Steel E 1 20.841 C17 Stainless Steel E 3 35.382

[0099] The results show the superior bond strength between Polymer Composition B (a PEEK-PEDEK) copolymer) and the metal, when the same pre-treatment has been applied to the metal, as illustrated by the following: [0100] compare Example 4 and Example C4; [0101] compare Example 5 and Example C5; [0102] compare Example 6 and Example C6; [0103] compare Example 7 and Example C7 [0104] compare Example 8 and Example C8; [0105] compare Example 9 and Example C9 [0106] compare Example 10 and Example C10; [0107] compare Example 11 and Example C11; [0108] compare Example 12 and Example C12; [0109] compare Example 13 and Example C13; [0110] compare Example 14 and Example C14; [0111] compare Example 15 and Example C15;

[0112] Metals may be advantageously overmoulded using compositions comprising the PEEK-PEDEK copolymer as illustrated by the following examples.

EXAMPLES 18 to 21 and c18 to c21overmouldinp of aluminium

[0113] Aluminium ingots (50 mm25 mm4 mm) were pre-treated either using Treatment 4 above (and overmoulded within 4 hours of etching) or by being sand-blasted using silica sand to produce a surface Ra of 5.

[0114] Samples were moulded on a BOY12A injection moulding machine with a tool temperature of 180 C. using moulding conditions as described in the manufacturer's datasheets for polymer composition D. For polymer Compositions C and G the following conditions were used: barrel temp 325 C. to 335 C., nozzle temp 340 C., holding pressure 30 bar, injection pressure 140 bar and screw speed 45 rpm. For each sample, the surface treated aluminium ingot was placed in the tool and allowed to reach the tool temperature and a layer of polymer (4 mm thick) was then moulded on to the surface of the aluminium.

[0115] The overmoulded samples were subjected to lap shear testing in a 3-point bend test with a 64 mm span at a speed of 2 mm/min and the max load before breakage determined. Results are provided in Table 2.

TABLE-US-00002 TABLE 2 Example Polymer No. Composition Pre-treatment Max Load (N) 18 C Sand-blasting 357 19 C Treatment 4 782 20 G Sand-blasting 327 21 G Treatment 4 736 C18 D Sand-blasting 186 C19 D Treatment 4 169

[0116] The maximum load strength demonstrates significantly improved bond strength of aluminium to PEEK-PEDEK compared to aluminium to PEEK.

[0117] Thus, it should now be appreciated that the PEEK-PEDEK copolymer unexpectedly and/or unpredictably bonds better to metals compared to PEEK.

[0118] Crystallinity referred to herein may be assessed as described in the following example.

EXAMPLE 22Differential Scanning Calorimetry of Polyaryletherketone of Example 1

[0119] Crystallinity may be assessed by several methods for example by density, by IR spectroscopy, by x ray diffraction or by differential scanning calorimetry (DSC). The DSC method has been used to evaluate the crystallinity that developed in the polymer of Example 1 using a Mettler Toledo DSC1 Star system with FRS5 sensor.

[0120] The Glass Transition Temperature (Tg), the Melting Temperature (Tm) and Heat of Fusions of Melting (Hm) for the polymer of Example 1 was determined using the following DSC method.

[0121] A dried sample of polymer was compression moulded into an amorphous film, by heating 7 g of polymer in a mould at 400 C. under a pressure of 50 bar for 2 minutes, then quenching in cold water producing a film of dimensions 120120 mm, with a thickness in the region of 0.20 mm. An 8 mg plus or minus 3 mg sample of each film was scanned by DSC as follows: [0122] Step 1 Perform and record a preliminary thermal cycle by heating the sample from 30 C. to 400 C. at 20 C./min. [0123] Step 2 Hold for 5 minutes. [0124] Step 3 Cool at 20 C./min to 30 C. and hold for 5 mins. [0125] Step 4 Re-heat from 30 C. to 400 C. at 20 C./min, recording the Tg, Tn, Tm, Hn and Hm.

[0126] From the DSC trace resulting from the scan in step 4, the onset of the Tg was obtained as the intersection of the lines drawn along the pre-transition baseline and a line drawn along the greatest slope obtained during the transition. The Tn was the temperature at which the main peak of the cold crystallisation exotherm reaches a maximum. The Tm was the temperature at which the main peak of the melting endotherm reached a maximum.

[0127] The Heat of Fusion for melting (Hm) was obtained by connecting the two points at which the melting endotherm deviates from the relatively straight baseline. The integrated area under the endotherm as a function of time yields the enthalpy (mJ) of the melting transition: the mass normalised heat of fusion is calculated by dividing the enthalpy by the mass of the specimen (J/g). The level of crystallisation (%) is determined by dividing the Heat of Fusion of the specimen by the Heat of Fusion of a totally crystalline polymer, which for the polymer tested is 130 J/g.

[0128] 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, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.