A COATING COMPOSITION AND COATING SYSTEM

Abstract

A coating composition comprising; a polyester material, and benzoguanamine or a derivative thereof, wherein the coating composition is substantially free of bisphenol A (BPA), bisphenol F (BPF), bisphenol A diglycidyl ether (BADGE) and bisphenol F diglycidyl ether (BFDGE), and wherein the coating composition, when cured, has a flexibility of at least 20 mm as measured according to the draw and re-draw test method with processing in 1% salt (NaCl) solution in tap water at 130 C. for 60 minutes and a scratch resistance of at least 700 g as measured according to ISO Standard 1518-1:2011.

Claims

1. A coating composition comprising; a polyester material, and benzoguanamine or a derivative thereof, wherein the coating composition is substantially free of bisphenol A (BPA), bisphenol F (BPF), bisphenol A diglycidyl ether (BADGE) and bisphenol F diglycidyl ether (BFDGE), and wherein the coating composition, when cured, has a flexibility of at least 20 mm as measured according to the draw and re-draw test method with processing in 1% salt (NaCl) solution in tap water at 130 C. for 60 minutes and a scratch resistance of at least 700 g as measured according to ISO Standard 1518-1:2011.

2. A coating composition according to claim 1, wherein the polyester material is formed from terephthalic acid, isophthalic acid, sebacic acid, or combinations thereof.

3. A coating composition according to claim 1 or 2, wherein the polyester material is formed from 2,2-dimethyl 1,3-propanediol (neopentyl glycol), 1,4-butandiol, 2-methyl 1,3-propanediol, ethylene glycol, 1,2-propanediol, 1,6-hexanediol, or combinations thereof.

4. A coating composition according to claim 1, wherein the polyester material comprises the reaction product of; (i) 1,2-propanediol, (ii) terephthalic acid, and (iii) a molecular weight increasing agent, wherein the polyester material has a number-average molecular weight (Mn) of at least 6,100 Da and a glass transition temperature (Tg) of at least 80 C.

5. A coating composition according to claim 4, wherein the molecular weight increasing agent (iii) comprises a polyacid, a polyol or a combination thereof; wherein the polyacid comprises a diacid of general formula (I)
ROOCX.sub.nCOOR formula (I) wherein each R independently represents hydrogen or an alkyl, alkenyl, alkynyl, or aryl group; n=0 or 1; wherein X represents a bridging group selected from: an alkylene group; an alkenylene group; an alkynylene group; an arylene group; wherein the bridge between the COOR groups is C.sub.1 or C.sub.2; and wherein the hydroxyl groups of the polyol are connected by a C.sub.1 to C.sub.3 alkylene group.

6. A coating composition according to any one of claims 1 to 5, wherein the coating composition comprises at least 4.5 wt % of benzoguanamine or a derivative thereof based on the total solid weight of the coating composition.

7. A coating composition according to any one of claims 1 to 6, wherein the coating composition comprises a polyester material, benzoguanamine or a derivative thereof and a further crosslinking material comprising a phenolic resin and an isocyanate resin.

8. A coating composition comprising: a polyester material, and a crosslinking material comprising a phenolic resin, and benzoguanamine or a derivative thereof, wherein the coating composition is substantially free of bisphenol A (BPA), bisphenol F (BPF), bisphenol A diglycidyl ether (BADGE) and bisphenol F diglycidyl ether (BFDGE), and wherein the coating composition, when cured, has a flexibility of at least 20 mm as measured according to the draw and re-draw test method with processing in 1% salt (NaCl) solution in tap water at 130 C. for 60 minutes and a scratch resistance of at least 700 g as measured according to ISO Standard 1518-1:2011.

9. A coating composition comprising: a polyester material, and a crosslinking material comprising an isocyanate resin, and benzoguanamine or a derivative thereof, wherein the coating composition is substantially free of bisphenol A (BPA), bisphenol F (BPF), bisphenol A diglycidyl ether (BADGE) and bisphenol F diglycidyl ether (BFDGE), and wherein the coating composition, when cured, has a flexibility of at least 20 mm as measured according to the draw and re-draw test method with processing in 1% salt (NaCl) solution in tap water at 130 C. for 60 minutes and a scratch resistance of at least 700 g as measured according to ISO Standard 1518-1:2011.

10. A coating composition according to claim 9, wherein the coating composition comprises from 0.5 to 30 wt % isocyanate resin based on the total solid weight of the coating composition.

11. A coating system comprising; an undercoat coating composition comprising; a polyester material, and benzoguanamine or a derivative thereof, and a powder overcoat coating composition comprising; a further polyester material, wherein the coating system is substantially free of bisphenol A (BPA), bisphenol F (BPF), bisphenol A diglycidyl ether (BADGE) and bisphenol F diglycidyl ether (BFDGE), and wherein the undercoat coating composition, when cured, has a flexibility of at least 20 mm as measured according to the draw and re-draw test method with processing in 1% salt (NaCl) solution in tap water at 130 C. for 60 minutes and a scratch resistance of at least 700 g as measured according to ISO Standard 1518-1:2011.

12. A coating system according to claim 11, wherein the undercoat coating composition is a coating composition according to any one of claims 2 to 10.

13. A coating system according to claim 11 or claim 12, wherein the coating system is applied to a food and/or beverage can to a seam line or weld along the body of the can.

14. A food and/or beverage can coated on at least a portion thereof with a coating composition comprising; a polyester material, and benzoguanamine or a derivative thereof, wherein the coating composition is substantially free of bisphenol A (BPA), bisphenol F (BPF), bisphenol A diglycidyl ether (BADGE) and bisphenol F diglycidyl ether (BFDGE), and wherein the coating composition, when cured, has a flexibility of at least 20 mm as measured according to the draw and re-draw test method with processing in 1% salt (NaCl) solution in tap water at 130 C. for 60 minutes and a scratch resistance of at least 700 g as measured according to ISO Standard 1518-1:2011.

15. A food and/or beverage can coated on at least a portion thereof with a coating system comprising; an undercoat coating composition comprising; a polyester material, and benzoguanamine or a derivative thereof, and a powder overcoat coating composition comprising; a further polyester material, wherein the coating system is substantially free of bisphenol A (BPA), bisphenol F (BPF), bisphenol A diglycidyl ether (BADGE) and bisphenol F diglycidyl ether (BFDGE), and wherein the undercoat coating composition, when cured, has a flexibility of at least 20 mm as measured according to the draw and re-draw test method with processing in 1% salt (NaCl) solution in tap water at 130 C. for 60 minutes and a scratch resistance of at least 700 g as measured according to ISO Standard 1518-1:2011.

Description

EXAMPLES

Coating Compositions

Coating Composition Example 1

[0189] Coating composition 1, containing a polyester material and benzoguanamine, was prepared according to the formulation in Table 1. All amounts are given in parts by weight (pbw) unless otherwise specified.

[0190] Items 1 to 9 were loaded into a vessel equipped with a stirring system and mixed at a speed of 1,500 rpm. Items 10 and 11 were mixed separately and then added to the vessel under stirring. Finally, items 12 and 13 were added and the contents of the vessel were mixed thoroughly by stirring.

[0191] The dry weight of benzoguanamine in coating composition example 1 is 5.65 wt % based on the total solid weight of coating composition example 1.

Coating Composition Example 2

[0192] Coating composition 2, containing a polyester material and benzoguanamine, was prepared according to the formulation in Table 2. All amounts are given in parts by weight (pbw) unless otherwise specified.

Comparative Coating Composition Example 1

[0193] Comparative Coating composition 1, containing a polyester material but no benzoguanamine, was prepared according to the formulation in Table 2. All amounts are given in parts by weight (pbw) unless otherwise specified.

TABLE-US-00001 TABLE 1 Formulation of Coating Composition 1 Coating Composition 1 1 Polyester resin .sup.1 57.16 2 Benzoguanamine 1 .sup.2 1.55 3 Benzoguanamine 1 .sup.3 2.95 4 Phenolic crosslinker 1 .sup.4 0.90 5 Phenolic crosslinker 2 .sup.5 8.97 6 Isocyanate crosslinker .sup.6 7.17 7 Solvent 1 .sup.7 10.36 8 Additive .sup.8 0.20 9 Wax .sup.9 2.66 10 Catalyst .sup.10 0.01 11 Solvent 1 .sup.7 0.09 12 Solvent 3 .sup.11 6.18 13 Solvent 4 .sup.12 1.80 Total 100 .sup.1 a linear polyester made from ethylene glycol, 2-methyl 1,3 propanediol, terephthalic acid and isophthalic acid and having an Mn of approx. 10,000 g .Math. mol and a Tg of 56 C. .sup.2 MAPRENAL (RTM) BF891 available from INEOS .sup.3 CYMEL (RTM) 1123 available from available from Allnex .sup.4 DUREZ (RTM) 33356 available from Sumitomo .sup.5 CURAPHEN (RTM) 40-852 available from Bitrez .sup.6 VESTANAT (RTM) EP-B 1186A available from Evonik .sup.7 Xylene .sup.8 BYK088 available from BYK-Chemie .sup.9 Lanolin wax (15 wt % solution) .sup.10 NACURE (RTM) 5925, a blocked acid catalyst available from King Industries Inc. .sup.11 2-butoxyethylacetate .sup.12 Butyl acetate

TABLE-US-00002 TABLE 2 Formulation of Coating Composition 2 and Comparative Coating Composition 1 Comparative Coating Coating Composition 2 Composition 1 1 Polyester resin .sup.1 62.0 64.7 2 Benzoguanamine .sup.2 4.2 3 Phenolic crosslinker 1 .sup.3 1.0 1.1 4 Phenolic crosslinker 2 .sup.4 10.4 10.9 5 Isocyanate crosslinker .sup.5 2.1 2.2 6 Additive .sup.6 0.2 0.2 7 Wax .sup.7 1.0 1.1 8 Catalyst 1 .sup.8 0.02 0.02 9 Catalyst 2 .sup.9 2.08 2.18 10 Solvent 1 .sup.10 6.3 6.5 11 Solvent 2 .sup.11 3.4 3.5 12 Solvent 3 .sup.12 2.1 2.2 13 Solvent 4 .sup.13 5.2 5.4 Total 100 100 .sup.1 DYNAPOL (RTM) LH 318 available from Evonik .sup.2 CYMEL (RTM) 1123 available from available from Allnex .sup.3 DUREZ (RTM) 33356 available from Sumitomo .sup.4 CURAPHEN (RTM) 40-852 available from Bitrez .sup.5 VESTANAT (RTM) EP-B 1186A available from Evonik .sup.6 BYK088 available from BYK-Chemie .sup.7 CERAFAK (RTM) 8RC7301 available from BYK-Chemie .sup.8 NACURE (RTM) 5925, a blocked acid catalyst available from King Industries Inc. .sup.9 TIBKAT (RTM) 620 (10% solution) available from TIB-Chemicals .sup.10 RHODIASOLV (RTM) RPDE available from Rhodia .sup.11 Xylene .sup.12 Diisobutyl ketone (DIBK) .sup.13 DOWANOL (RTM) PM available from the DOW Chemical Company

Overcoat Coating Composition Example 1

[0194] Overcoat coating composition 1 was prepared according to the formulation in Table 3. All amounts are given in parts by weight (pbw) unless otherwise specified.

[0195] Items 1 a and 1b were loaded into a reactor with stirring and heating. Item 1 was then added to the reaction mixture. The reaction mixture was heated up to 80 C. under stirring until the polyester resin was fully dissolved. Once dissolution was complete the reaction mixture was cooled down to 25-30 C. Items 2 and 3 were then homogenised in drums and used to adjust the viscosity of the reaction mixture during the addition of item 4. Item 4 was loaded slowly under sufficient stirring to obtain a powder dispersion with no agglomerates bigger than 30 m in the blend.

[0196] After the temperature of the reaction mixture has decreased to the relevant temperature 30-40 C. item 7 and item 8 were added to the reaction mixture under stirring. Items 9 and 10 were then homogenised before loading into the reaction mixture. Stirring was increased to disperse the wax. Items 11 and 12 were pre-mixed before then being added under stirring. The viscosity was adjusted to 75-85s according to ISO6 at 25 C. by the addition of item 13. The reaction mixture was then filtered with a 10 to 50 m set.

TABLE-US-00003 TABLE 3 Formulation of Overcoat Coating Composition 3 Overcoat Coating Composition 1 1 Polyester resin .sup.1 14.67 1a Solvent 1 .sup.2 13.06 1b Solvent 2 .sup.3 5.6 2 Solvent 1 .sup.2 6.90 3 Solvent 3 .sup.4 6.90 4 PVC resin .sup.5 22.99 5 Solvent 4 .sup.6 8.05 6 Solvent 1 .sup.2 4.90 7 Phenolic resin .sup.7 8.62 8 Additive 1 .sup.8 1.72 9 Wax 1 .sup.9 2.02 10 Wax 2 .sup.10 2.02 11 Catalyst .sup.11 0.06 12 Solvent 5 .sup.12 0.51 13 Solvent 1 .sup.2 2.00 Total 100 .sup.1 DYNAPOL (RTM) L952 available from Evonik .sup.2 SOLVESSO (RTM) 100 .sup.3 DOWANAL (RTM) PM (methoxy propanol) available from Dow .sup.4 Butyl glycol .sup.5 VINNOL (RTM) P70 available from Wacker Chemie .sup.6 RPDE, a blend of siccinic, adipic and fumaric esters .sup.7 PR516 available from Cytec .sup.8 DEHYSOL (RTM) D82 H available from BASF .sup.9 LUBAPRINT (RTM) 121/H available from Bader-Munzig .sup.10 TF1780 0.1, a PTFE-modified polyethylene wax .sup.11 H.sub.3PO.sub.4 .sup.12 Methoxypropanol

Overcoat Coating Composition Example 4

[0197] Overcoat coating composition 4 is a commercial BPA Ni Powder Side Stripe available as VECODUR VP1091 from Valspar.

Comparative Coating Composition Example 2

[0198] Comparative coating composition 2 is commercial polyester based gold lacquer available from Metlac S.p.A containing a combination of a polyester material and phenolic materials.

Comparative Coating Composition Example 3

[0199] Comparative coating composition 3 is commercial polyester based gold lacquer available from PPG Industries containing a combination of a polyester material and phenolic materials.

Comparative Coating Composition Example 4

[0200] Comparative coating composition 4 is commercial organosol lacquer available from PPG Industries containing a combination of a polyvinyl chloride organosol and a phenolic material.

Comparative Coating Composition Example 5

[0201] Comparative coating composition 5 is commercial epoxy-based gold lacquer available from PPG Industries containing a combination of an epoxy material, phenolic materials and a melamine-formaldehyde material.

Metal Substrates

[0202] The coatings were applied to a range of metal substrates as follows.

[0203] Tinplate panels: Coated panels were prepared by coating a tinplate substrate using a wire wound lab rod. The coatings were applied as either a single layer (i.e. one coat) or as a double layer (i.e. 2 coats). The dry film weight for each coating layer was 9-10 g/m.sup.2 (gsm). After application, the panels were dried for 10 minutes at 200 C.

[0204] Tinplate sheets: Coated sheets of tinplate were prepared by coating a tinplate sheet using a roller coater. The coatings were applied as either a single layer (i.e. one coat) or as a double layer (i.e. 2 coats). The dry film weight for each coating layer was 9-10 g/m.sup.2 (gsm) unless otherwise indicated. After application, the sheets were dried for 10 minutes at 200 C. Tests were performed on either the tinplate sheet as prepared by this method or the tinplate sheets were subsequently formed into a can body, non-easy open ends (NEOE), easy open ends (EOE) or deep drawn cans and the tests were performed on these components.

[0205] The properties of the coatings were then tested by the following methods. The results are shown in Tables 4 to 8.

Test Methods

[0206] Scratch resistance: this test was carried out according to ISO standard 1518-1:2011. A scratch apparatus, supplied with alternative current of 200/250 V, 50 Hz, has an arm which supports the scratch stylus and is set up to allow the arm to slide at a constant rate of 3-4 cm/sec over the test panel. The scratch stylus has a counterweight and a tungsten carbide ball of 1 mm in diameter. Coated panels were up to 127 mm long and not more than 1.65 mm thick. The coated panels were fixed in the apparatus and the scratch stylus, loaded with weights up to 2000 g, was drawn over the panels at a speed of 3-4 cm/sec. The measurements were taken at increasing load weights in increments of 100 g. The panels were inspected visually for coating penetration.

[0207] The weight, in grams (g), at which coating penetration (e.g. coating failure) occurred was recorded.

[0208] FlexibilityDraw and re-draw: The coated panel was placed under a stamping machine and a can sized 18 mm30 mm (heightdiameter) was stamped. This was then placed in a second machine and the can was transformed into a deeper drawn shape sized 26 mm24 mm (heightdiameter). The shaped can was then processed in 1% salt (NaCl) solution in tap water and also various other simulants. Shaped cans were placed in a container containing simulant such that they were submerged in the solution. The container was then placed in an autoclave and processed at 130 C. for 60 minutes. Common solutions, in addition to 1% salt (NaCl) solution are tap water and 1% lactic acid in tap water. After processing, the can was observed visually and the non-torn part of the coating composition along the straight edge of the can was measured. The values were recorded in millimetres (mm) with the maximum value being 26 mm.

[0209] Mobility: Surface mobility was measured using an ALTEK Model 9505 mobility/lubricity tester. The sample was mounted in the machine and a test sequence was initiated according to the manufacturer's instructions. The coefficient of friction, as determined from the test sequence, was quoted from the reading of the electronic analogue meter.

[0210] Wedge Bend Test (WBT): A 10cm4cm coated panel was bent on a 6 mm steel rod to form a U-shaped strip 10cm long and 2cm wide. The U-shaped strip was then placed onto a metal block with a built in tapered recess. A 2kg weight was dropped onto the recessed block containing the U-shaped strip from a height of 60cm in order to from a wedge. The test piece was then immersed in a copper sulphate (CuSO4) solution acidified with hydrochloric acid (HCI) for 2 minutes, followed by rinsing with tap water. The sample was then carefully dried by blotting any residual water with tissue paper. The length of coating without any fracture was measured. The result was quoted in mm passed. The wedge bends were tested in triplicate and the average value was quoted.

[0211] Processing in various simulants: Coated panels cut into 10cm x 5cm panels were placed in a container containing simulant such that half of the panel was submerged in the solution. The container was then placed in an autoclave and processed at 130 C. for 60 minutes. Common solutions are tap water, 1% salt in tap water and 1% lactic acid in tap water. After this time, panels were examined visually for blushing (i.e. whitening of the coating), blistering, discoloration and adhesion loss. Grade 0 corresponds to perfect film appearance with no discernible attack. Grade 5 corresponds to complete attack of the film.

[0212] Adhesion was checked after processing. The coating was crosshatched and checked for removal with tape. Grade 0 corresponds to good adhesion with no removal of coating and grade 5 to complete loss of adhesion.

[0213] Porosity: The porosity value is directly linked to the surface of metal that has not been correctly covered with coating. For ends the porosity is measured using a Sencon enamel rater in a 4-second mode using an electrolyte consisting of 1000 g deionized water, 5 g sodium chloride, 10 g potassium ferrocyanide and 1.43 g sodium dioctylsulfosuccinate solution at 65%. The current can pass if there is uncoated metal and is displayed in milliamps. The goal is to obtain 0.0 mA that corresponds to perfect metal coverage. The same measurement can be done for porosity in can using for example a Manfred Kuhnke rater.

[0214] Sulfur staining: Sulfur staining corresponds to black color that appears when cans are containing some specific food like split peas, sardines, tuna or pet food. Split peas are prepared in water. Swelled peas are then put in a can coated with evaluated lacquer before to be processed for 1 h at 130 C. Cans were opened after approximately 12 hours. The results were assessed visually and rated on a scale of 0-5.

[0215] Powder Side Stripe Adhesion: A powder overcoat composition was applied manually onto the panels coated with coating composition 2 and comparative coating composition 1. The powder overcoat composition was then cured at 295 C. for 45 seconds. The coated panel was then cut along the edges of the powder overcoat coating composition and the cutting edge adhesion of the powder overcoat coating composition to the undercoat coating composition was then evaluated according to the level of peeling from the undercoat coating composition. The results were assessed visually at time=0 and at time=24 hours. Grade 4 is the highest rating, i.e. shows the least amount of peeling, and 1 is the lowest rating, i.e. shows the highest amount of peeling.

[0216] Feathering: The goal of this test is to check that coating resists to food can opening in case of easy open end. Indeed coating has to be fully adherent to substrate even after he is cut when closure is opened with easy open end system. Delamination is measured in millimeters and corresponds to uncovered substrate at the edge of cut resulting from closure opening.

TABLE-US-00004 TABLE 4 Results on tinplate panels Tinplate panel (ETP 2.8) Substrate 1 coat Coating Coating Comparative composition composition Coating example 1 composition 1 Scratch 700 g 600 g resistance Mobility 0.05 0.045 Wedge Bend Test 98 98 Wedge Bend Test 99 95 with over-curing Powder side Okay Okay stripe adhesion Tap water, 1 hour, 130 C. Blush (liquid 0 0 phase) 1% salt solution, 1 hour, 130 C. Flexibility 26 mm 26 mm Blush (liquid 0 0 phase) Porosity 1 1.3 1% lactic acid solution, 1 hour, 130 C. Flexibility 26 mm 26 mm Blush (liquid 3 3 phase) Porosity 2 1.5 Split peas Sulphur staining 2 3 Blush (liquid 0 2 phase)

TABLE-US-00005 TABLE 5 Results on tinplate sheets Tinplate sheets Tinplate sheets (ETP 2.8) (ETP 5.6) Substrate 1 coat 2 coats Coating composition Coating Comparative Coating composition Coating composition example 1 composition 1 example 1 Scratch resistance 775 g 750 g 1,400 g Mobility 0.06 0.05 0.055 Wedge Bend Test 80 83 90 Powder side stripe 0 0 0 adhesion Tap water, 1 hour, 130 C. Blush (liquid phase) 0 0 0 1% salt solution, 1 hour, 130 C. Flexibility 26 mm 26 mm 20 mm Blush (liquid phase) 0 3 0 Blush (vapour phase) 0 0 0 Porosity 1.3 6 0.3 1% lactic acid solution, 1 hour, 130 C. Flexibility 26 mm 26 mm 26 mm Blush (liquid phase) 3 3 0 Porosity 3 3 0.8

TABLE-US-00006 TABLE 6 Results on tinplate sheets formed into non-easy open end (NEOE) cans Substrate Tinplate cans Coating Coating Coating Coating Coating Comparative Composition composition composition composition composition coating example 1 example 1 example 1 example 1 composition 1 Dry film weight on body ETP 2.8 9 gsm 9 gsm 8 gsm ETP 5.6 9 gsm 18.4 gsm Dry film weight on non-easy open end ETP 5.6 8.9 gsm 17.7 gsm ECCS 9 gsm 19 gsm 17 gsm Porosity min 2.03 mA 3.09 mA 5.71 mA 0.14 mA 5.43 mA Porosity 0.63 mA 0.12 mA 0.35 mA 0.00 mA 0.91 mA max Porosity 1.37 mA 0.97 mA 1.30 mA 0.04 mA 2.34 mA average

TABLE-US-00007 TABLE 7 Results on easy open ends (EOE) Substrate Tinplate Tinplate Tinplate Tin-free steel Undercoat Coating Comparative Coating Coating Coating composition coating composition composition composition example 1 composition 2 example 1 example 1 Overcoat Overcoat Comparative Coating Coating Coating Coating coating composition composition Composition Composition composition 3 example 1 example 1 Example 2 Feathering 0.6 0.1 0.6 0.15 Porosity 0.5 mA 0.3 mA 0.3 mA 0.5 mA Rivet aspect no attack no attack no attack no attack 1% salt solution, 1 hour, 130 C. Porosity 1.5 mA 2.1 mA 2.1 mA 2.1 mA Rivet aspect no attack no attack no attack no attack 1% lactic acid solution, 1 hour, 130 C. Porosity 1.3 mA 1.2 mA 1.4 mA Rivet aspect no attack no attack no attack Split Peas Sulphur 4 4 4 staining Blush (liquid 3 4 0 phase)

TABLE-US-00008 TABLE 8 Results of powder stripe adhesion Undercoat Coating Comparative coating composition 2 composition 1 Overcoat Overcoat coating Overcoat coating composition 4 composition 4 Cutting edge 4 1 adhesion (initial) Cutting edge 4 1 adhesion (24 hrs)

[0217] The results demonstrate that the coating compositions and/or systems according to the present invention perform as well as, or better, than those of the comparative examples. Furthermore, the coating compositions and/or systems of the present invention show a good performance on all substrates.

[0218] 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 the public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

[0219] All of the features disclosed in this specification (including any accompanying claims, abstract 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.

[0220] Each feature disclosed in this specification (including any accompanying claims, abstract 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.

[0221] 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 or drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.