ANAEROBICALLY CURABLE COMPOSITIONS

Abstract

An anaerobically curable composition comprising: a liquid anaerobically curable component; a solid anaerobically curable component; a solid thermoplastic polyurethane resin having a molecular weight in the range of from 40,000 g/mol to 100,000 g/mol and a melting point in the range of from 40° C. to 80° C.; and a curing component for curing the anaerobically curable components.

Advantageously, the compositions of the invention are substantially solid and may be used as threadlockers.

Claims

1. An anaerobically curable composition comprising: a liquid anaerobically curable component; a solid anaerobically curable component; a solid thermoplastic polyurethane resin having a molecular weight in the range of from 40,000 g/mol to 100,000 g/mol and a melting point in the range of from 40° C. to 80° C.; and a curing component for curing the anaerobically curable components.

2. The composition of claim 1, wherein the liquid anaerobically curable component is present in an amount of from about 4 wt % to about 44 wt % based on the total weight of the composition.

3. The composition of claim 1, wherein the solid anaerobically curable component is present in an amount of from about 5 wt % to about 45 wt % based on the total weight of the composition.

4. The composition of claim 1, wherein the solid thermoplastic polyurethane resin is present in an amount of from about 20 wt % to about 75 wt % based on the total weight of the composition.

5. The composition of claim 1, wherein the curing component for curing the anaerobically curable components is present in an amount of from about 0.1 to about 10 wt % based on the total weight of the curable composition.

6. The composition of claim 1, wherein the liquid anaerobically curable component comprises a liquid (meth)acrylate monomer component.

7. The composition of claim 6, wherein the liquid (meth)acrylate monomer component is one or more selected from those having the formula:
H.sub.2C=CGCO.sub.2R.sup.8, wherein G is hydrogen, halogen or alkyl groups having from 1 to 4 carbon atoms, and R.sup.8 is selected from alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkaryl, alkaryl or aryl groups having from 1 to about 16 carbon atoms, any of which may be optionally substituted or interrupted as the case may be with silane, silicon, oxygen, halogen, carbonyl, hydroxyl, ester, carboxylic acid, urea, urethane, carbonate, amine, amide, sulfur, sulfonate, sulfone and the like.

8. The composition of claim 1 wherein the solid anaerobically curable component comprises one or more solid (meth)acrylate monomer components.

9. The composition of claim 1 wherein the curing component comprises one or more selected from the group consisting of 1-acetyl-2-phenylhydrazine, N,N-dimethyl para toluidine, N,N-diethyl para toluidine, N,N-diethanol para toluidine, N,N-dimethyl ortho toluidine, N,N-dimethyl meta toluidine, indoline, 2-methylindoline, isoindoline, indole, 1,2,3,4-tetrahydroquinoline, 3-methyl-1,2,3,4-tetrahydro-quinoline, 2-methyl-1,2,3,4-tetrahydroquinoline, and 1,2,3,4-tetrahydroquinoline-4-carboxylic acid.

10. The composition according to claim 1, further comprising an initiator of free radical polymerization.

11. The composition according to claim 10, wherein the initiator of free radical polymerization is one or more selected from the group consisting of: cumene hydroperoxide (“CHP”), para-menthane hydroperoxide, t-butyl hydroperoxide (“TBH”), t-butyl perbenzoate, benzoyl peroxide, dibenzoyl peroxide, 1,3-bis(t-butylperoxyisopropyl)benzene, diacetyl peroxide, butyl 4,4-bis(t-butylperoxy)valerate, p-chlorobenzoyl peroxide, t-butyl cumyl peroxide, t-butyl perbenzoate, di-t-butyl peroxide, dicumyl peroxide, 2,5-dimethyl-2,5-di-t-butylperoxyhexane, 2,5-dimethyl-2,5-di-t-butyl-peroxyhex-3-yne, 4-methyl-2,2-di-t-butylperoxypentane, t-amyl hydroperoxide, 1,2,3,4-tetramethylbutyl hydroperoxide and combinations thereof.

12. The composition according to claim 10, wherein the initiator of free radical polymerisation comprises an encapsulated peroxide.

13. The composition according to claim 1, further comprising a cure accelerator.

14. The composition according to claim 13, wherein the cure accelerator comprises one or more metallocenes; and/or a cure accelerator embraced by ##STR00019## wherein X is CH.sub.2, O, S, NR.sup.4, CR.sup.5R.sup.6 or C═O; R is one or more of hydrogen, alkyl, alkenyl, alkynl, hydroxyalkyl, hydroxyalkenyl, or hydroxyalkynl; R.sup.1-R.sup.6 are each individually selected from hydrogen, halogen, amino, carboxyl, nitro, alkyl, alkenyl, alkynyl, hydroxyalkyl, hydroxyalkenyl, hydroxyalkynyl, or alkaryl; R.sup.7 is hydrogen or CHR.sup.8R.sup.9, wherein R.sup.8 and R.sup.9 are each individually selected from hydrogen, halogen, amino, carboxyl, nitro, alkyl, alkenyl, alkynyl, hydroxyalkyl, hydroxyalkenyl, hydroxyalkynyl, or alkaryl; and n is 0 or 1.

15. The composition according to claim 1 provided in tape form, filament form or in the form of a coated substrate.

16. The composition according to claim 1 provided as a coating on a thread or a fibre.

17. A tape comprising an anaerobically curable composition according to claim 1 and one or more release liners.

18. A threaded member comprising at least one threaded face, wherein said at least one threaded face comprises an anaerobically curable composition according to claim 1.

19. The threaded member according to claim 18, wherein the anaerobically curable composition is in tape form, filament form or in the form of a coated substrate.

20. The threaded member according to claim 19, wherein the anaerobically curable composition in tape form, filament form or in the form of a coated substrate is applied to the threaded face.

21. A method of manufacturing a threaded member comprising a threadlocking composition, comprising: (a) providing at least one threaded member comprising at least one threaded face, (b) applying to said at least one threaded face, an anaerobically curable composition according to claim 1.

22. The method of manufacturing a threaded member according to claim 21, wherein the anaerobically curable composition is in tape form, filament form or in the form of a coated substrate.

23. The method of manufacturing a threaded member according to claim 21, wherein the anaerobically curable composition in tape form, filament form or in the form of a coated substrate is wrapped at least partially around the at least one threaded face of the threaded member.

24. A method of assembling threaded members comprising: (a) providing a first threaded member, comprising at least one threaded face; (b) applying an anaerobically curable composition according to claim 1 to said at least one threaded face; (c) providing a second threaded member capable of matingly engaging said first threaded member; matingly engaging said first and second threaded members and thereby exposing said anaerobically curable composition to an anaerobic environment for a time sufficient for said anaerobically curable composition to cure between said first and second threaded members.

25. The method according to claim 24, wherein the anaerobically curable composition is in tape form, filament form or in the form of a coated substrate.

26. The method according to claim 25, wherein the anaerobically curable composition in tape form, filament form or in the form of a coated substrate is wrapped at least partially around said at least one threaded face.

27. A method for manufacturing a tape for threadlocking comprising: (a) mixing at least one solid thermoplastic polyurethane resin having a molecular weight in the range of from 40,000 g/mol to 100,000 g/mol and a melting point in the range of from 40° C. to 80° C., and solvent; (b) mixing therewith: a liquid anaerobically curable component, a solid anaerobically curable component and a curing component for curing the anaerobically curable components; (c) applying the mixture of step (ii) to a release liner; (d) allowing the solvent to evaporate, to thereby form a tape comprising the anaerobically curable composition according to claim 1 and a release liner.

Description

DETAILED DESCRIPTION

[0048] As outlined above, the present invention provides an anaerobically curable composition comprising: a liquid anaerobically curable component; a solid anaerobically curable component; a solid thermoplastic polyurethane resin having a molecular weight in the range of from 40,000 g/mol to 100,000 g/mol and a melting point in the range of from 40° C. to 80° C.; and a curing component for curing the anaerobically curable components.

Definitions and Standard Test Methods

[0049] The term “liquid” means in a liquid state within the temperature range of from about 5° C. to 30° C., suitably in a liquid state at room temperature and at atmospheric pressure.

[0050] The term “solid” means in a solid state within the temperature range of from about 5° C. to 40° C., suitably in a solid state at room temperature and at atmospheric pressure. Solid state is defined as the state of matter in which materials are not fluid but retain their boundaries without support, the atoms or molecules occupying fixed positions with respect to each other and Linable to move freely.

[0051] In respect of the present invention tack free means dry to the touch yet the composition will not flake off during handling or use. For example an article to which the composition of the invention is applied is dry to the touch. An article to which a composition of the invention has been applied is considered dry to the touch if 20 of such articles are individually placed on dry tissue paper for four hours and there is no change in appearance of the tissue.

[0052] Molecular weights disclosed herein are determined in accordance with ISO 13885-1:2008, “Binders for paints and varnishes—Gel permeation chromatography (GPC)—Part 1: Tetrahydrofuran (THF) as eluent”.

[0053] Melting and re-solidification temperature ranges were measured in accordance with ISO 1137-1:2016 “Plastics—Differential scanning calorimetry (DSC)—Part 1 General Principles”.

Liquid Anaerobically Curable Component

[0054] Suitably, the liquid anaerobically curable component comprises a liquid (meth)acrylate monomer component.

[0055] The liquid (meth)acrylate component may comprises one or more (meth)acrylate monomers selected from beta-carboxy ethyl acrylate, isobornyl acrylate, n-octyl acrylate, n-decyl acrylate, cyclohexyl acrylate, tetrahydrofurfuryl acrylate, 2-ethylhexyl acrylate, ethoxyethoxyethyl acrylate, ethoxylated phenyl monoacrylate, hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, isooctyl acrylate, n-butyl acrylate, neopentyl glycol diacrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, dipropylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, 1,6-hexane diol diacrylate, tripropylene glycol diacrylate, glycerol triacrylate, trimethylol propane diacrylate, trimethylol propane triacrylate, pentaerythritol tetraacrylate, phenoxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, cyclohexyl methacrylate, glycerol mono-methacrylate, glycerol 1,3-dimethacrylate, trimethyl cyclohexyl methacrylate, methyl triglycol methacrylate, isobornyl methacrylate, trimethylolpropane trimethacrylate, neopentyl glycol dimethacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, 1,6-hexanediol dimethacrylate, hydroxybutyl methacrylate, tetrahydrofurfuryl methacrylate, cyclohexyl methacrylate, phenoxyethyl methacrylate, glycerol methacrylate, glycidyl methacrylate, methyl methacrylate and methacrylic acid and mixtures thereof.

[0056] Preferred liquid (meth)acrylate monomers include 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, tetrahydrofurfuryl methacrylate, isobornyl methacrylate, phenoxyethyl methacrylate and methacrylic acid.

[0057] One or more suitable (meth)acrylates may be chosen from among polyfunctional (meth)acrylates, such as, but not limited to, di- or tri-functional (meth)acrylates like polyethylene glycol di(meth)acrylates, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate (“TRIEGMA”), tetraethylene glycol dimethacrylate, dipropylene glycol dimethacrylate, di-(pentamethylene glycol) dimethacrylate, tetraethylene diglycol diacrylate, diglycerol tetramethacrylate, tetramethylene dimethacrylate, ethylene dimethacrylate, neopentyl glycol diacrylate, trimethylol propane triacrylate, polyethyleneglycol di(meth)acrylates and bisphenol-A mono and di(meth)acrylates, such as ethoxylated bisphenol-A (meth)acrylate (“EBIPMA”), and bisphenol-F mono and di(meth)acrylates, such as ethoxylated bisphenol-F (meth)acrylate.

[0058] For example, the redox curable component may include Bisphenol A dimethacrylate:

##STR00010##

[0059] Suitably, the redox curable composition may include ethoxylated bisphenol A di(meth)acrylate.

[0060] Still other (meth)acrylates that may be suitable for use herein are silicone (meth)acrylate moieties (“SiMA”), such as those taught by and claimed in U.S. Pat. No. 5,605,999 (Chu), the disclosure of which is hereby expressly incorporated herein by reference.

[0061] Other suitable materials may be chosen from polyacrylate esters represented by the formula:

##STR00011##

where R.sup.4 is a radical selected from hydrogen, halogen or alkyl of from 1 to about 4 carbon atoms; q is an integer equal to at least 1, and preferably equal to from 1 to about 4; and X is an organic radical containing at least two carbon atoms and having a total bonding capacity of q plus 1. With regard to the upper limit for the number of carbon atoms in X, workable monomers exist at essentially any value. As a practical matter, however, a general upper limit is about 50 carbon atoms, such as desirably about 30, and desirably about 20.

[0062] For example, X can be an organic radical of the formula:

##STR00012##

where each of Y.sup.1 and Y.sup.2 is an organic radical, such as a hydrocarbon group, containing at least 2 carbon atoms, and desirably from 2 to about 10 carbon atoms, and Z is an organic radical, preferably a hydrocarbon group, containing at least 1 carbon atom, and preferably from 2 to about 10 carbon atoms. Other materials may be chosen from the reaction products of di- or tri-alkylolamines (e.g., ethanolamines or propanolamines) with acrylic acids, such as are disclosed in French Pat. No. 1,581,361.

[0063] Suitable oligomers with (meth)acrylate functionality may also be used. Examples of such (meth)acrylate-functionalized oligomers include those having the following general formula:

##STR00013##

where R.sup.5 represents a radical selected from hydrogen, alkyl of from 1 to about 4 carbon atoms, hydroxy alkyl of from 1 to about 4 carbon atoms, or

##STR00014##

where R.sup.4 is a radical selected from hydrogen, halogen, or alkyl of from 1 to about 4 carbon atoms; R.sup.6 is a radical selected from hydrogen, hydroxyl, or

##STR00015##

m is an integer equal to at least 1, e.g., from 1 to about 15 or higher, and desirably from 1 to about 8; n is an integer equal to at least 1, e.g., 1 to about 40 or more, and desirably between about 2 and about 10; and p is 0 or 1.

[0064] Typical examples of acrylic ester oligomers corresponding to the above general formula include di-, tri- and tetraethyleneglycol dimethacrylate; di(pentamethyleneglycol)dimethacrylate; tetraethyleneglycol diacrylate; tetraethyleneglycol di(chloroacrylate); diglycerol diacrylate; diglycerol tetramethacrylate; butyleneglycol dimethacrylate; neopentylglycol diacrylate; and trimethylolpropane triacrylate.

[0065] While di- and other polyacrylate esters, and particularly the polyacrylate esters described in the preceding paragraphs, can be desirable, monofunctional acrylate esters (esters containing one acrylate group) also may be used.

[0066] Suitable compounds can be chosen from among are cyclohexylmethacrylate, tetrahydrofurfuryl methacrylate, hydroxyethyl acrylate, hydroxypropyl methacrylate, t-butylaminoethyl methacrylate, cyanoethylacrylate, and chloroethyl methacrylate.

[0067] Another useful class of materials are the reaction product of (meth)acrylate-functionalized, hydroxyl- or amino-containing materials and polyisocyanate in suitable proportions so as to convert all of the isocyanate groups to urethane or ureido groups, respectively.

[0068] The so-formed (meth)acrylate urethane or urea esters may contain hydroxy or amino functional groups on the non-acrylate portion thereof. (Meth)acrylate esters suitable for use may be chosen from among those of the formula:

##STR00016##

where X is selected from —O— and

##STR00017##

where R.sup.9 is selected from hydrogen or lower alkyl of 1 through 7 carbon atoms; R.sup.7 is selected from hydrogen, halogen (such as chlorine) or alkyl (such as methyl and ethyl radicals); and R.sup.8 is a divalent organic radical selected from alkylene of 1 through 8 carbon atoms, phenylene and naphthylene.

[0069] These groups upon proper reaction with a polyisocyanate, yield a monomer of the following general formula:

##STR00018##

where n is an integer from 2 to about 6; B is a polyvalent organic radical selected from alkyl, alkenyl, cycloalkyl, cycloalkenyl, aryl, alkaryl, alkaryl and heterocyclic radicals both substituted and unsubstituted, and combinations thereof; and R.sup.7, R.sup.8 and X have the meanings given above.

[0070] Depending on the nature of B, these (meth)acrylate esters with urea or urethane linkages may have molecular weights placing them in the oligomer class (such as about 1,000 g/mol up to about 5,000 g/mol) or in the polymer class (such as about greater than 5,000 g/mol).

[0071] Other unsaturated reactive monomers and oligomers such as styrenes, maleimides, vinyl ethers, allyls, allyl ethers and those mentioned in U.S. Pat. No. 6,844,080B1 (Kneafsey et al.) can be used. Vinyl resins as mentioned in U.S. Pat. No. 6,433,091 (Xia) can also be used. Methacrylate or acrylate monomers containing these unsaturated reactive groups can also be used.

[0072] Of course, combinations of these (meth)acrylates and other monomers may also be used.

Solid Anaerobically Curable Component

[0073] The anaerobically curable composition of the invention comprises a solid anaerobically curable component. The solid anaerobically curable component may be a solid (meth)acrylate resin. Suitably the solid (meth)acrylate resin is selected from the list of suitable (meth)acrylate components listed above.

Solid Thermoplastic Polyurethane Resin

[0074] The anaerobically curable composition of the invention comprises a solid thermoplastic polyurethane resin having a molecular weight in the range of from 40,000 g/mol to 100,000 g/mol and a melting point in the range of from 40° C. to 80° C. Suitable solid thermoplastic polyurethane resins include Pearlbond® 100, Pearlbond® 106, Pearlbond® 120, Pearlbond® 122, Pearlbond® 180, Pearlstick® 5712, Pearlstick® 5714 and Pearlstick® 40-70/08 which are commercially available from Lubrizol, Carrer del Gran Vial, 17, 08160 Montmelo, Barcelona, Spain.

Examples

[0075] Anaerobically curable compositions as provided in Table 1 were formulated in tape form.

TABLE-US-00001 TABLE 1 Composition 1 2 3 4 5 Amt Amt Amt Amt Amt (wt (wt (wt (wt (wt Component %) %) %) %) %) Pearlbond 100 30 29.25 23.59 18.64 15.34 Pearlbond 106 30 29.25 23.59 18.64 15.34 Vinyl novolac resin 30 30 23.59 18.61 15.30 Ethoxylated bisphenol A 5.5 5.5 11.88 — — dimethacrylate Sartomer CN159 — — — 18.74 15.43 Polyurethane — — — 18.74 15.43 methacrylate resin Naphthoquinone (5% 0.2 0.2 — — — in polyethylene glycol dimethacrylate) Tetra sodium EDTA (3.5 1.0 1.0 — — — wt % in water/propylene glycol) Saccharin 0.4 0.4 0.75 0.76 0.62 Acetylphenylhydrazine 0.4 0.4 0.75 0.76 0.62 Cumene hydroperoxide 2.5 — 3.97 5.1 4.19 Microencapsulated — 4.0 — — — benzoyl peroxide Microencapsulated — — 11.88 — 17.73 ethoxylated bisphenol A dimethacrylate Polyurethane methacrylate resin used is the reaction product of a flexible methylene ether diol reacted with a molar excess of toluene diisocyanate and then end-capped with HEMA. “Amt” = amount.

[0076] The compositions of Table 1 were prepared as follows:

[0077] The solid thermoplastic polyurethane urethane component having a molecular weight in the range of from 40000 g/mol to 100000 g/mol and a melting point in the range of from 40° C. to 80° C. of each composition was soaked in ethyl acetate overnight before mixing to dissolution in a Speedmixer DAC150.147. The remaining components were then added and mixing was continued until each of the components had dissolved. For compositions comprising microencapsulated peroxides or methacrylates, the encapsulated components will not dissolve and mixing was continued until the microencapsulated components had formed a dispersion in the solution. Each solution was then cast onto siliconized polyester release liner (HiFi SR4-122, 75 micron thick) using an Elcometer 4340 automatic film coater maintained with a coating plate temperature of 30° C. After coating the ethyl acetate was allowed to evaporate the heated coating plate. Dry to touch films were obtained.

[0078] Material properties of the uncured films formed from the compositions of table 1 were assessed after solvent evaporation. The percentage elongation of each film was measured in accordance with ASTM D882-02. Tensile break strength of each film was measured in accordance with ASTM D882-09.

TABLE-US-00002 TABLE 2 Composition Property 1 2 3 4 5 Elongation (%) 437 444 ND 12 9 Tensile break strength 7.14 3.4 ND 0.83 0.83 (MPa)

[0079] The films of Examples 1 to 5 show that the elongation of the film can vastly vary while the film maintains integrity and also gives excellent adhesive performance when cured.

[0080] The threadlocking performance of each of the films formed from the compositions of the invention specified in Table 1 were assessed on M10 nuts and bolts according to ISO 10964. The thickness of the films were determined. For films comprising microencapsulated components, the thickness of such films were measured at points where the microcapsules were not prominent. The compositions of the invention were applied to M10 bolts, and threaded assemblies were formed with M10 nuts capable of matingly engaging said M10 bolts. The threaded assemblies were kept at room temperature (20° C. to 25° C.) for 24 hours, prior to measuring break and prevail strengths of the cured compositions. The results for each composition on a variety of substrates are provided in Table 3.

TABLE-US-00003 TABLE 3 Composition Property 1 2 3 4 5 Film thickness (μm) 60 150 150 70 150 Bolt/Nut assembly Break strength/Prevail strength (Nm) Black oxide mild steel 6.3/6.9 9.5/10 12.9/8.7 8.0/5.1 11.3/5.8 Zinc Phosphate 9.6/8.5 3.7/2.9  8.3/7.4 6.3/7.0  9.2/8.0 Zinc dichromate 5.1/4.3  12/9.3 ND 3.4/4.2  9.6/7.8 Stainless steel 2.3/1.9 2.6/2.2 10.5/7.0 5.9/3.9 11.1/6.6

[0081] The compositions of Table 4 were manufactured in the same manner as the compositions of Table 1.

TABLE-US-00004 TABLE 4 Composition 6 7 Component Amt. (wt %) Amt. (wt %) Pearlbond 106 60 — Pearlbond 100 — 60 Methacrylated novolac 30 30 Ethoxylated bisphenol A 6.6 6.6 dimethacrylate Acetylphenylhydrazine 0.4 0.4 Saccharin 0.4 0.4 Cumene hydroperoxide 2.5 2.5 Reactint Red 0.1 0.1

[0082] Compositions 6 and 7 were formulated as tapes as per the method above for compositions 1 to 5.

[0083] The threadlocking performance of each of the compositions of Table 4 was assessed on M10 nuts and bolts according to ISO 10964. The compositions of the invention were applied to M10 bolts, and threaded assemblies were formed with M10 nuts capable of matingly engaging said M10 bolts. The threaded assemblies were kept at room temperature (20° C. to 25° C.) for 24 hours, prior to measuring break and prevail strengths of the cured compositions. The results for each composition on a variety of substrates are provided in Table 5.

TABLE-US-00005 TABLE 5 Composition Property 6 7 Bolt/Nut assembly Break strength/Prevail strength (Nm) Black oxide 7.23/8.5  6.1/3.4 Zinc Phosphate 6.0/7.3 5.9/5.7

[0084] The elongation and tensile strength properties of the tapes formed from the compositions of Table 4 were also assessed.

TABLE-US-00006 TABLE 6 Composition Property 6 7 Elongation (%) 488 454 Tensile break strength (MPa) 8.07 9.33

[0085] The films may also be used to structural bond mated assemblies. Tensile strengths were determined in accordance with ISO 4587 for the film made according to example 1. Results are shown as a mean value with the standard deviation within a set of test specimen shown. For 0.5″ overlap area tests, the film was cut in pieces to cover the bond area and placed onto a test coupon. The mating coupon was then placed on top and the test specimen was clamped and placed in an oven heated to 80° C. for a period of 20 minutes. The test specimens were then removed and left for 24 hours at room temperature before testing. Test results were obtained for stainless steel (grade SUS 304), polycarbonate and acrylonitrile butadiene styrene (ABS).

TABLE-US-00007 Stainless steel/Stainless steel 5.1 ± 0.2 MPa (cohesive failure) Polycarbonate/Polycarbonate 8.0 ± 0.5 MPa (substrate failure) ABS/ABS 4.8 ± 0.7 MPa (cohesive failure)

[0086] The results show excellent adhesion especially for plastics.

[0087] The words “comprises/comprising” and the words “having/including” when used herein with reference to the present invention are used to specify the presence of stated features, integers, steps or components but do not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

[0088] It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination.