Antifriction coating

Abstract

An antifriction coating composition which comprises: a resin binder, a polyamide thickener, solvent and a solid lubricant wherein the resin binder comprises a mixture of phenolic resin, epoxy resin and optionally a silicone resin.

Claims

1. An antifriction coating composition comprising: (i) a resin binder; (ii) a polyamide thickener; (iii) a solvent; and (iv) a solid lubricant; wherein the resin binder (i) comprises a mixture comprising 15 to 50% by weight of a phenolic resin, 50 to 85% by weight of an epoxy resin and 10 to 30% by weight of a silicone resin, each based on 100% by weight of the (i) resin binder.

2. The antifriction coating composition in accordance with claim 1, wherein the resin binder (i) comprises the reaction product of a phenol ether resin, a diglycidyl ether of Bisphenol A and optionally, a polyorganosiloxane resin comprising at least two different units chosen from those of formulae R.sub.3SiO.sub.0.5 (M units), R.sub.2SiO.sub.2/2 (D units), RSiO.sub.3/2 (T units) and SiO.sub.4/2 (Q units), with at least one of these units being a T unit or a Q unit.

3. The antifriction coating composition in accordance with claim 2, wherein the resin binder (i) comprises the reaction product of the polyorganosiloxane resin and the polyorganosiloxane resin is a T resin, a DT resin or a MDT resin.

4. The antifriction coating composition in accordance with claim 1, wherein the polyamide thickener (ii) is a polyamide wax.

5. The antifriction coating composition in accordance with claim 4, wherein the polyamide wax comprises the reaction product of a long-chain carboxylic acid and mono functional amines, polyfunctional amines, or ammonia.

6. The antifriction coating composition in accordance with claim 4, wherein the polyamide wax comprises the reaction product of one or more alkylenediamines and one or more linear fatty acids or mixtures of fatty acids.

7. The antifriction coating composition in accordance with claim 1, wherein the solid lubricant (iv) is selected from the group of graphite, molybdenum disulfide (MoS.sub.2), polytetrafluoroethylene (PTFE), a silicone wax, a solid hydrocarbon wax, a mixture of PTFE and polyolefin wax, zinc sulphide, tricalcium phosphate, calcium fluoride, and mixtures thereof.

8. The antifriction coating composition in accordance with claim 1, wherein the solvent (iii) is selected from the group of water, alcohols, ketones, esters, heterocyclic aromatic solvents, non-heterocyclic aromatic solvents, and mixtures thereof.

9. The antifriction coating composition in accordance with claim 8, wherein the solvent (iii) is a mixture of one or more alcohols and one or more esters, in a ratio of from 10:90 by weight to 50:50 by weight.

10. The antifriction coating composition in accordance with claim 1, further comprising: (v) one or more silane coupling agents.

11. The antifriction coating composition in accordance with claim 10, wherein the silane coupling agent (v) is selected from the group of methyltrimethoxysilane, (3-glycidoxypropyl) trimethoxysilane, (3-glycidoxypropyl) triethoxysilane, and mixtures thereof.

12. The antifriction coating composition in accordance with claim 1, comprising: (i) 15 to 30% by weight of the resin binder; (ii) 1 to 8% by weight of the polyamide thickener; (iii) 50 to 80% by weight of the solvent; (iv) 0.5 to 15% by weight of the solid lubricant; (v) 0 to 3% by weight of a silane coupling agent; and optionally, (vi) an additive; each based on 100% by weight of the total antifriction coating composition components.

13. The antifriction coating composition in accordance with claim 1, further comprising: one or more pigments.

14. The antifriction coating composition in accordance with claim 13, wherein the pigment comprises calcium fluoride and/or aluminium oxide.

15. A method of forming an antifriction coating on a substrate, the method comprising the step of: applying an antifriction coating composition to a surface of the substrate to form a coating; wherein the antifriction coating composition is in accordance with claim 1 and optionally, wherein the antifriction coating composition is applied by brushing, dipping, dip-spinning, spraying, printing, and/or roller coating.

16. The method in accordance with claim 15, further comprising the step of: curing the coating at a temperature of between 120? C. and 200? C. after application, and optionally, wherein the coating has a thickness of between 3 ?m and 25 ?m.

17. The method in accordance with claim 15, wherein the substrate is: I) pre-treated or post-treated with phosphating layers, Zn-rich coatings, Zn-flakes base coats, Zn-plating layers, or hot dip Zn-galvanizing layers; II) selected from the group of fasteners or threaded connections used in industrial applications, fasteners used in automotive applications, door, bonnet and boot lock parts, hinges, door stoppers, window guides, seat belt components, brake rotors and drums, bushings, rods, piston skirts, piston rings or instrument panels; or III) both I) and II).

18. A coated substrate formed in accordance with the method of claim 16.

Description

EXAMPLE 1

(1) In this example it was unexpectedly identified that the use of amide waxes as thickeners rather than industrial standard thickeners were optimum for the composition described herein. Generally for typical Anti-Friction Coating formulations thickening systems like Bentone products are widely used. It was unexpectedly found that the use of polyamide wax based thickeners enhanced the corrosion protection performance of the composition as will be seen below in which Tables 1a and 1b depict the compositions (amounts indicated are weight % of the composition) utilized and Table 1c provides details of the corrosion protection results.

(2) TABLE-US-00001 TABLE 1a Formulation Comp 1 Comp 2 Comp 3 Comp 4 Comp 5 Butylacetate 46.8 48.3 48.2 50.7 52.3 (solvent) n-butanol 15.0 15.5 15.5 16.3 16.8 (solvent) Epoxy resin 14.8 15.3 16.0 16.0 15.9 (binder) Si-resin 4.3 4.4 4.7 4.7 4.6 (binder) Phenolic resin 4.9 5.0 5.3 5.3 5.3 (binder) Phosphoric 0.3 0.3 0.3 0.3 0.2 acid (catalyst) Thickener 4.2 4.4 4.6 1.6 2.2 Al.sub.2O.sub.3 Al.sub.2O.sub.3 Al.sub.2O.sub.3 Bentone? Bentone? 38V SD-2 Solid lubricant 9.7 6.8 5.4 5.1 1.6 PTFE-wax mix Wax 0 0 0 0 1.1 Total 100 100 100 100 100

(3) In Table 1a it will be seen that the thickeners in the prepared antifriction coatings were the traditionally used aluminium trihydroxide and bentone clay type thickeners. BENTONE? 38 V is an organically modified hectorite commercially available from Elementis Specialities of Diegem Belgium and BENTONE? SD-2 is an organic derivative of a bentonite clay.

(4) TABLE-US-00002 TABLE 1b Formulation 1 2 3 4 5 Butylacetate 57.6 57.2 56.9 56.7 56.0 n-butanol 16.3 16.2 16.1 16.0 15.9 Epoxy resin 13.6 13.6 13.5 13.4 13.3 Si-resin 4.0 4.0 3.9 3.9 3.9 Phenolic resin 4.5 4.5 4.5 4.5 4.4 Phosphoric acid 0.2 0.2 0.2 0.2 0.2 Polyamide thickener 1.5 2.0 2.0 3.0 4.0 Solid lubricant PTFE-wax mix 1.4 0.9 1.4 1.4 1.4 Wax 0.9 0.9 1.5 0.9 0.9

(5) A reference coating was additionally tested. Ref 1 referred to in Table 1c below relates to a commercial AFC Molykote? D-708 from Dow Corning Corporation of Midland Mich. In the case of Ref. 1 however, two coats were applied due to the comparatively low viscosity of the composition (see Table 1c).

(6) The antifriction coating indicated above as formulation 1 in Table 1b was prepared using the following process based on cold blending, using a mixer with stirrer:

(7) The solvents were intermixed. The epoxy resin was then dissolved in the solvent mixture with stirring. The silicone resin was then introduced and thoroughly mixed into the epoxy resin solution resulting from the above, again with stirring. The thickener and solid lubricants were subsequently introduced and mixed into the solution, mix with dissolver

(8) After which the phenolic cross-linker and in this case catalyst (phosphoric acid) were introduced and intermixed. All compositions throughout the examples were made using the above methodology. Additives can be introduced into the solvent solution at any time but typically for the above additives were added simultaneous with the introduction of the thickener and lubricant materials or immediately thereafter.

(9) It was found that the polyamide thickener utilized had good compatibility/resistance with the solvent mixture and the resulting uncured coating showed excellent viscosity stability over time. The viscosity of the AFC formulations used in Table 1c was measured in accordance with DIN EN ISO 2431 using ISO Cup 4. All other viscosity measurements of compositions provided in the remaining examples use the same method (unless otherwise indicated).

(10) The coating compositions were applied onto M10 type steel fasteners with ISO 898-1 strength ratings (otherwise known as property classes) of 8.8, 10.9 or 12.9 as tabulated below or otherwise indicated below. In the case of Table 1c the fasteners used were M10 class 8.8 fasteners.

(11) In the case of Table 1c, each coating composition above was applied onto M10 class 8.8 fasteners by dip-spinning after which the resulting anti-friction coating (AFC) was cured on the so treated fasteners for a period of 20 minutes at 200? C. This application process was used for coating all fasteners throughout the examples. It is to be noted however that this coating process was utilized merely for example.

(12) The resulting fasteners coated in the cured AFC as described in Tables 1a and 1b were then tested for corrosion resistance using with method DIN EN ISO 9227 and the of red rust formation after 16 h in salt-spray tester is given in below table 1c in respect of both the thread of the fastener and the head of the fastener. As fasteners are normally handled as bulk goods and therefore exposed to impacts during handling, packaging and transport a procedure has been developed to evaluate the coated fasteners also under this aspect, i.e. under a more rigorous testing. For this a required number of coated fasteners were placed in a cylindrical container (pail) equipped in its inside with stumble traps; the pail was rotated at low rotational speed for a period of 10 minutes and then the coated fasteners were blasted for 2 min with air pressure at 4 bar (4?10.sup.5 Nm.sup.?2) and then the anti-corrosion properties were determined with method DIN EN ISO 9227 (henceforth this more rigorous testing is referred to as tumbling):

(13) TABLE-US-00003 TABLE 1c Corrosion - Corrosion - after 16 hrs after 16 hrs (on thread/ (on thread/ on head) on head) after tumbling [% of area [% of area Coat affected affected Viscosity Thickness by red rust by red rust Formulation [s] (?m) formation] formation] Comp 1 43 5.3 6/2 14/10 Comp 2 46 5.4 2/0.6 7/5 Comp 3 42 7.6 5/1 25/14 Comp 4 42 8.9 14/16 26/18 Comp 5 33 4.7 5.7/2 7/6 1 22 2.2 4/9 6/14 2 24 2.8 3/6.5 8/18 3 24.5 2.5 0.7/1.1 2.0/3.0 4 27 2.6 1.8/1.8 2.6/6 5 42 5.1 1.1/0.8 1.8/2.2 5 (2) 38 8.6 1.1/0.8 Ref 1 14 6.1 1.0/0.6 20/11

(14) It is to be noted that the formulations using traditional thickening systems (i.e. Comps 1-5) showed limited corrosion resistance after mechanical damage.

EXAMPLE 2

Reference Materials

(15) Solid lubricants were identified by testing modified versions of solid lubricants normally used for Anti-Friction Coatings. Of these the most common are perhaps MoS.sub.2 (Molybdenum disulfide), graphite, PTFE and synthetic waxes.

(16) As references two commercially available AFCs were tested for coefficient of friction COF). The AFCs assessed were Molykote? D-708 (which contains a PTFE based solid lubricant) and Molykote? D-3484 (a MoS.sub.2 based AFC).

(17) Sample fasteners were coated as previously described in Example 1 with the following Curing conditions: Molykote? D-708=20 min @ 200? C.; Molykote? D-3484=15 min @ 170? C.

(18) The resulting treated fasteners were analysed for their coefficient of Friction (COF) using a Schatz testing machine (type 5413-4504) according to standard ISO 16047. Selected material pairing in the contact of the under head was a steel strip (with hardness and surface treatment as per standard ISO 16047, par. 7.2.2). Bolts of class 8.8 were pre-tensioned with 26 kN on the fastener tester (Schatz test machine) in this example.

(19) The Results are Provided in Table 2 Below:

(20) TABLE-US-00004 TABLE 2 Coat Viscosity Thickness Formulation [s] (?m) COF.sub.tot COF.sub.thread COF.sub.head Ref 1(a) 14 10.7 0.124 (0.043) 0.183 (0.110) 0.093 (0.021) Ref 1(b) 14 10.7 0.123 (0.051) 0.177 (0.126) 0.095 (0.025) Ref 1(c) 14 17.7 0.120 (0.061) 0.183 (0.147) 0.087 (0.019) Ref 2 60 5.3 0.065 (0.035) 0.096 (0.090) 0.049 (0.023)

(21) Requirements from the Industry are:

(22) Total Coefficient of Friction (COF) range: mean value between 0.09 and 0.15 Scatter (max minus min measured value) of the total COF: 0.03.

(23) The values in Table 2 for COF are mean values from ten samples unbracketed values and scatter values in brackets. In view of the latter it was considered that Ref 2 was showing COFs which were too low and the Ref 1 samples used were showing inadequate lubrication of the threads, inducing a too high scatter of the total COF.

EXAMPLE 3

(24) Given the results in the previous Examples alternative solid lubricants were sought. Formulation 6, 7 and 8 in Table 3a depict formulations containing traditional solid lubricant materials, namely powder 3M? Dyneon? TF 9205 PTFE a micronized fluorocarbon powder from 3M and Micropro? 600 as hereinbefore described.

(25) TABLE-US-00005 TABLE 3a Formulation 6 7 8 Butylacetate 59.34 55.78 56.52 n-butanol 15.80 15.77 15.89 Epoxy resin 13.29 13.23 13.37 Si-resin 3.85 3.83 3.87 Phenolic resin 4.41 4.37 4.43 Phosphoric acid 0.21 0.20 0.22 Polyamide thickener 1.32 3.98 1.33 Dyneon? TF-9205 0 0 4.37 Micropro 600 1.78 2.84 0 Total 100 100 100

(26) Such compositions were then compared with formulations 9 to 14 in Table 3b using the preferred solid lubricants, described above in the introduction to the examples, Polyfluo? 400XF and Micropro? 600 and identified henceforth as Solid lubricant PTFE-wax mix.

(27) TABLE-US-00006 TABLE 3b Formulation 9 10 11 12 13 14 Butylacetate 53.41 53.82 55.28 56.06 55.39 56.57 n-butanol 15.10 15.21 15.63 15.85 16.21 16.00 Epoxy resin 12.67 12.77 13.12 13.30 13.14 13.44 Si-resin 3.67 3.70 3.79 3.86 3.81 3.89 Phenolic resin 4.21 4.25 4.35 4.42 4.36 4.46 Phosphoric 0.20 0.20 0.20 0.20 0.20 0.20 acid Polyamide 3.82 3.94 3.94 4.04 4.00 4.02 thickener Solid lubricant 6.06 6.10 2.80 1.36 1.40 0.54 PTFE-wax mix Wax 0.87 0 0.90 0.91 1.49 0.88 Total 100 100 100 100 100 100

(28) On the fastener tester (Schatz test machine) bolts of class 8.8 were pre-tensioned with 26 kN and bolts of class 10.9 were pre-tensioned with 38 kN.

(29) TABLE-US-00007 TABLE 3c Coating Bolt Formulation Thickness (?m) Type COF.sub.tot COF.sub.thread COF.sub.head 10 7.9 8.8 0.098 (0.015) 0.120 (0.030) 0.085 (0.025) 10 7.0 8.8 0.127 (0.037) 0.143 (0.055) 0.118 (0.033) 10 10.3 10.9 0.103 (0.019) 0.137 (0.021) 0.085 (0.027) 9 6.7 8.8 0.110 (0.032) 0.124 (0.066) 0.102 (0.032) 11 5.6 8.8 0.119 (0.029) 0.135 (0.067) 0.110 (0.040) 12 8.6 10.9 0.115 (0.025) 0.148 (0.034) 0.097 (0.039) 12 8.1 10.9 0.097 (0.044) 0.143 (0.059) 0.073 (0.037) 12 8.8 10.9 0.102 (0.050) 0.138 (0.073) 0.083 (0.048) 12 6.2 10.9 0.111 (0.046) 0.140 (0.094) 0.096 (0.047) 12 8.1 8.8 0.126 (0.046) 0.150 (0.064) 0.122 (0.049) 13 8.3 10.9 0.092 (0.032) 0.125 (0.057) 0.075 (0.046) 13 9.4 10.9 0.085 (0.034) 0.109 (0.063) 0.073 (0.038) 14 8.1 10.9 0.128 (0.056) 0.148 (0.073) 0.117 (0.060) 7 9.0 10.9 0.141 (0.070) 0.167 (0.088) 0.128 (0.074) 6 10.9 0.138 (0.044) 0.152 (0.062) 0.131 (0.056) 8 10.9 0.138 (0.022) 0.185 (0.031) 0.114 (0.039)

(30) Again, the values in Table 3c for COF are mean values from ten samples unbracketed values and scatter values (in brackets), whereas each bolt sample was tightened three times consecutively; the statistical values were calculated considering each of the three consecutive tightening for each bolt (this means: for ten bolts the mean and scatter values are statistically calculated 30 measured COF-values).

(31) Some formulations were also tested for high strength bolts of class 12.9 as depicted in Table 3d. These were welding nuts pre-tensioned with 47 kN. Data refer to mean values and ?-range of 10 bolts tested, each of them tightened for one time.

(32) TABLE-US-00008 TABLE 3d Coating Weight Bolt Formulation (g/bolt) Type COF.sub.tot COF.sub.thread COF.sub.head 10 0.047 12.9 0.088 (0.015) 0.088 (0.016) 0.088 (0.021) 12 0.045 12.9 0.119 (0.020) 0.118 (0.035) 0.118 (0.013)
Note: it was not possible to measure the film thickness on this type of bolt as the shaft does not have a plane surface, but a full thread along the whole shaft; we controlled the thickness by measuring the coat weight.

(33) Corrosion resistance was also tested and the results are depicted in in Table 3e.

(34) TABLE-US-00009 TABLE 3e Corrosion - Corrosion - Coat after 16 hrs after 16 hrs Viscosity Thickness (on thread/ (on thread/on head) Formulation [s] (?m) on head) after tumbling 8 34 6.6 4.0/0.6 4.0/3.0 6 42 8.3 1.3/0.0 4.0/3.0 7 35 7.0 3.0/2.4 12 42 5.1 1.1/0.8 1.8/2.2 12 38 8.6 1.1/0.8 13 33 8.3 1.1/0.8 14 37 5.8 2.0/1.6 11 39 5.6 1.2/0.9 9 30 6.7 3.0/2.0 10 36 7.9 1.3/1.5

EXAMPLE 4

(35) The results depicted in Table 3c above can be seen to have showed that several of the coatings therein resulted in too large a scatter of coefficient of friction on threads. In order to try and decrease the level of scatter a selection of silanes were introduced into the composition and compared to see if their presence resulted in a reduction of scatter. The compositions tested are indicated in Table 4a.

(36) TABLE-US-00010 TABLE 4a Formulation 15 16 17 18 19 20 21 Butylacetate 55.53 55.53 54.72 54.72 55.53 55.53 55.53 n-butanol 15.70 15.70 15.47 15.47 15.70 15.70 15.70 Epoxy resin 13.17 13.17 12.98 12.98 13.17 13.17 13.17 Si-resin 3.81 3.81 3.76 3.76 3.81 3.81 3.81 Phenolic resin 4.37 4.37 4.32 4.32 4.37 4.37 4.37 Phosphoric acid 0.20 0.20 0.20 0.20 0.20 0.20 0.20 Polyamide thickener 3.96 3.96 3.90 3.90 3.96 3.96 3.96 Solid lubricant PTFE-wax mix 1.35 1.35 2.77 2.77 1.35 1.35 1.35 Wax 0.90 0.90 0.89 0.89 0.90 0.90 0.90 ?-aminopropyl triethoxysilane 1.00 1,6-bis(trimethoxysilyl) hexane 1.00 (Ethylenediaminepropyl) 1.00 trimethoxysilane Methyltrimethoxysilane 1.00 1.00 Glycidoxypropyl- 1.00 1.00 trimethoxysilane Total 100 100 100 100 100 100 100

(37) The formulations in Table 4a were then tested for coefficient of friction using the same methodology as previously described again using class 8.8 (26 kN) and 10.9 (38 kN) fasteners. The results are depicted in Table 4b:

(38) TABLE-US-00011 TABLE 4b Coating Bolt Formulation Thickness (?m) Type COF.sub.tot COF.sub.thread COF.sub.head 17 8.4 8.8 0.112 (0.025) 0.128 (0.038) 0.130 (0.033) 18 8.4 8.8 0.107 (0.024) 0.118 (0.042) 0.100 (0.033) 19 8.4 8.8 0.124 (0.038) 0.157 (0.058) 0.106 (0.064) 20 7.2 8.8 0.130 (0.067) 0.150 (0.073) 0.119 (0.065) 21 10.6 8.8 0.118 (0.028) 0.149 (0.062) 0.101 (0.057) 15 8.9 8.8 0.133 (0.040) 0.149 (0.039) 0.123 (0.055) 16 7.0 8.8 0.121 (0.025) 0.133 (0.041) 0.115 (0.042)

(39) Formulations 17 and 18 depicted in Table 4a were also tested with class 12.9 (47 kN) fasteners as depicted in Table 4c.

(40) TABLE-US-00012 TABLE 4c Coating Weight Bolt Formulation (g/bolt) Type COF.sub.tot COF.sub.thread COF.sub.head 17 0.043 12.9 0.077 (0.012) 0.073 (0.017) 0.079 (0.010) 18 0.043 12.9 0.079 (0.009) 0.088 (0.029) 0.074 (0.013)
Note: it was not possible to measure the film thickness on this type of bolt as the shaft does not have a plane surface, but a full thread along the whole shaft; we controlled the thickness by measuring the coat weight.

(41) The compositions in Table 4a were also tested as previously described in respect to corrosion resistance and the results are depicted in Table 4d.

(42) TABLE-US-00013 TABLE 4d Viscosity Coat Thickness Corrosion - after 16 hrs Formulation [s] (?m) (on thread/on head) 19 30 8.4 1.5/0.5 20 32.8 7.2 0.9/0.4 21 49/gel 10.6 2.0/1.0 15 28 8.9 4.0/3.0 17 33 8.4 1.6/1.5 16 28 7.0 1.3/0.5 18 32 8.4 1.8/0.6

(43) Overall it was determined that methyltrimethoxysilane and glycidoxypropyltrimethoxysilane were the best silanes to introduce into the composition in order to reduce the scatter previously seen.

EXAMPLE 5

(44) In this example a series of pigments are introduced into compositions of the type previously described. These appear to also assist identifying compositions which meet the product requirement profile (PRP) for engine fasteners.

(45) The pigments utilized in example 5 were: (i) calcium fluoride lubricant grade (D50=15 ?m) supplied by Solvay Fluor GmbH and identified in the Table 5a as Caf2-LG (ii) Calcium fluoride superfine (D50=11 ?m) supplied by Solvay Fluor GmbH and identified in the Table 5a as CaF2-SF (iii) Aeroxide Alu C 805 an Aluminium oxide product supplied by Degussa and identified in the Table 5a as Alu C 805.
The compositions tested are indicated in Table 5a.

(46) TABLE-US-00014 TABLE 5a Formulation 22 23 24 25 26 27 Butylacetate 54.29 54.32 53.92 54.53 54.23 54.23 n-butanol 15.35 15.36 15.25 15.42 15.34 15.34 Epoxy resin 12.88 12.89 12.80 12.94 12.87 12.87 Si-resin 3.73 3.73 3.70 3.74 3.72 3.72 Phenolic resin 4.28 4.27 4.24 4.30 4.27 4.27 Phosphoric acid 0.19 0.19 0.20 0.19 0.20 0.20 Polyamide thickener 3.91 3.87 3.84 3.90 3.87 3.87 Solid lubricant PTFE-wax mix 1.32 1.32 2.78 1.32 2.80 2.80 Wax 0.88 0.88 0.88 Ca-F2-LG 3.17 Ca-F2-SF 3.18 3.27 Al.sub.2O.sub.3 2.77 2.70 2.70

(47) The compositions in Table 5a were tested as previously described in respect to corrosion resistance. The formulations in Table 5a to were tested for coefficient of friction as depicted in Tables 5b using the same methodology as previously described again using class 8.8 (26 kN) and 10.9 (38 kN) fasteners. For both of the above type bolts, the film thickness of the cured coating is measured on the shaft of the bolt. Unfortunately 12.9 type bolts have a continuous thread along the shaft and as such the level of coat weight was indicated instead of coating thickness. The values for bolts 8.8 and 10.9 refer to values considering three consecutive tightenings of each tested bolt; for the bolt 12.9 data refer to one tightening.

(48) TABLE-US-00015 TABLE 5b Viscosity Coat Thickness Corrosion - after 16 hrs Formulation [s] (?m) (on thread/on head) 22 33 7.7 0.3/0.2 23 30 7.4 0.3/0.2 24 29 6.2 2.0/2.0 25 46 10.0 0.4/0.4 26 42 9.6 1.6/0.8 27 43 7.4 2.3/1.0

(49) The formulations in Table 5a were tested for coefficient of friction using the same methodology as previously described again using class 8.8 (26 kN) and 10.9 (38 kN) fasteners. The results are depicted in Table 5c:

(50) TABLE-US-00016 TABLE 5c Coating Thickness Formulation (?m) Bolt Type COF.sub.tot COF.sub.thread COF.sub.head 24 6.2 8.8 0.116 (0.025) 0.0127 (0.063) 0.109 (0.034) 26 9.6 8.8 0.115 (0.037) 0.142 (0.072) 0.101 (0.033) 27 7.4 8.8 0.123 (0.019) 0.140 (0.046) 0.113 (0.029) 22 7.7 8.8 0.125 (0.034) 0.142 (0.051) 0.115 (0.049) 23 7.4 8.8 0.125 (0.035) 0.143 (0.053) 0.114 (0.048) 25 10.0 8.8 0.121 (0.033) 0.158 (0.051) 0.100 (0.031)

(51) Formulations 24, 26 and 27 depicted in Table 5a were also tested with class 12.9 (47 kN) fasteners as depicted in Table 5d. The film thickness of the cured coating is typically measured on the shaft of the bolt. Unfortunately 12.9 type bolts have a continuous thread along the shaft and as such the level of coating was indicated. Therefore the coating is measure by coat weight as opposed to thickness.

(52) TABLE-US-00017 TABLE 5d Coating Bolt Formulation Weight (g/bolt) Type COF.sub.tot COF.sub.thread COF.sub.head 24 0.043 12.9 0.081 (0.015) 0.090 (0.024) 0.076 (0.010) 26 0.045 12.9 0.083 (0.022) 0.083 (0.022) 0.083 (0.023) 27 0.045 12.9 0.087 (0.008) 0.087 (0.008) 0.088 (0.010)

(53) The pigments introduced in example 5 particularly support corrosion protection despite the fact that they are not considered to be anti-corrosion additives.

EXAMPLE 6

(54) In this example a further series of pigments are introduced into compositions of the type previously described. These appear to also assist identifying compositions which meet the product requirement profile (PRP) for engine fasteners.

(55) The pigments utilized in example 6 were: (i) Melamine cyanurate a salt of melamine and iso-cyanuric acid in crystal form sold as Melapur? MC25 having a mean particle size (manufacturer's information) of 5 ?m. This was found effective alone or in combination with a micronized amide wax (bis-stearyl-ethylenediamide) in a powder form (mean particle size (manufacturer's information) 6.5 ?m which is manufactured by Clariant as Ceridust? 3910; (ii) Polyamide-12 polymer in flake and/or sphere form with a mean particle size (manufacturer's information) of 5 ?m sold as Nylon SP-500 which is manufactured by Toray Industries; and (iii) Polyetheretherketone (PEEK) polymer in powder form with a mean particle size of Ketaspire? KT-820 from Solvay.
The compositions tested are indicated in Table 6a.

(56) TABLE-US-00018 TABLE 6a Formulation 28 29 30 31 32 33 Butylacetate 57.89 57.00 58.34 57.89 58.56 58.94 n-butanol 16.40 16.15 16.53 16.41 16.59 16.72 Epoxy resin 10.60 10.43 10.67 10.59 10.72 10.78 Si-resin 3.07 3.02 3.09 3.07 3.10 3.12 Phenolic resin 3.52 3.40 3.59 3.52 3.60 3.66 Phosphoric acid 0.20 0.20 0.20 0.20 0.20 0.20 Polyamide thickener 3.24 3.09 3.23 3.23 3.27 3.32 Solid lubricant PTFE- 1.17 1.21 1.12 1.10 1.19 1.15 wax mix Amide Wax 0.83 1.62 MCA 2.92 4.51 1.41 1.39 Nylon SP-500 1.76 PEEK 1.10 Methyltrimethoxysilane 1.00 1.00 1.00 1.00 1.00 1.00

(57) The compositions in Table 6a were tested as previously described in respect to coefficient of friction and the results are depicted in Table 6b for compositions 28 and 29 (MCA), Table 6c for compositions 30 and 31 (MCA+Amide wax), Table 6d for composition 32 (Nylon SP-500) and Table 6e for composition 33 (PEEK).

(58) TABLE-US-00019 TABLE 6b Coating Thickness Formulation (?m) Bolt Type COF.sub.tot COF.sub.thread COF.sub.head 28 5.6 8.8 0.126 (0.041) 0.0146 (0.086) 0.115 (0.029) 29 7.7 8.8 0.134 (0.054) 0.161 (0.096) 0.120 (0.039) 28 8.0 10.9 0.120 (0.049) 0.159 (0.117) 0.099 (0.022) 29 10.8 10.9 0.125 (0.062) 0.189 (0.107) 0.092 (0.043) 28 0.043 12.9 0.095 (0.012) 0.104 (0.028) 0.090 (0.013) 29 0.047 12.9 0.108 (0.016) 0.127 (0.035) 0.096 (0.029)

(59) The formulations in Table 6a were tested for coefficient of friction as depicted in Tables 6b-6e using the same methodology as previously described again using class 8.8 (26 kN) and 10.9 (38 kN) fasteners. For both of the above type bolts, the film thickness of the cured coating is measured on the shaft of the bolt. Unfortunately 12.9 type bolts have a continuous thread along the shaft and as such the level of coat weight was indicated instead of coating thickness. The values for bolts 8.8 and 10.9 refer to values considering three consecutive tightenings of each tested bolt; for the bolt 12.9 data refer to one tightening.

(60) Combinations of the MCA pigment in conjunction with amide type waxes were tested in Table 6c and it was found that this combination also gave good results. It will be seen that MCA alone and in combination with the micronized amide wax are able to increase the COF and also to reduce considerably the scatter on the underhead.

(61) TABLE-US-00020 TABLE 6c Coating Bolt Formulation Thickness (?m) Type COF.sub.tot COF.sub.thread COF.sub.head 30 10.0 8.8 0.124 (0.038) 0.135 (0.062) 0.118 (0.032) 31 6.4 8.8 0.118 (0.028) 0.136 (0.063) 0.108 (0.017) 30 10.1 10.9 0.115 (0.063) 0.155 (0.112) 0.095 (0.044) 31 11.8 10.9 0.120 (0.052) 0.190 (0.123) 0.083 (0.025) 30 0.046 12.9 0.089 (0.021) 0.092 (0.013) 0.087 (0.036) 31 0.050 12.9 0.091 (0.009) 0.098 (0.033) 0.087 (0.006)

(62) In the case of Table 6d the pigments were replaced by an alternative pigment Nylon SP-500.

(63) TABLE-US-00021 TABLE 6d Coating Bolt Formulation Thickness (?m) Type COF.sub.tot COF.sub.thread COF.sub.head 32 7.0 8.8 0.127 (0.055) 0.146 (0.093) 0.117 (0.033) 32 11.1 10.9 0.122 (0.055) 0.163 (0.149) 0.101 (0.027) 32 0.042 12.9 0.090 (0.010) 0.088 (0.012) 0.092 (0.012)
Again good results were obtained with a general increase in the COF as well as scatter reduction, particularly on the underhead.
Similarly In the case of Table 6e the pigment was replaced by a further alternative pigment PEEK polymer powder.

(64) TABLE-US-00022 TABLE 6e Coating Bolt Formulation Thickness (?m) Type COF.sub.tot COF.sub.thread COF.sub.head 33 6.3 8.8 0.133 (0.030) 0.148 (0.064) 0.125 (0.026) 33 13.9 10.9 0.128 (0.057) 0.171 (0.107) 0.106 (0.042) 33 0.054 12.9 0.110 (0.086) 0.128 (0.129) 0.100 (0.062) 33 0.054 12.9 0.089 (0.023) 0.098 (0.017) 0.084 (0.032)

(65) Again it can be seen that good results were achieved. Again good results were obtained with a general increase in the COF as well as scatter reduction, particularly on the underhead.

EXAMPLE 7

(66) In this example a Titanium dioxide (TiO.sub.2) pigment was introduced into the composition as a replacement for the other pigments utilised in Examples 5 and 6.

(67) The formulations in Table 7a to were tested for coefficient of friction as depicted in Table 7b using the same methodology as previously described again using class 8.8 (26 kN) and 10.9 (38 kN) fasteners. For both of the above type bolts, the film thickness of the cured coating is measured on the shaft of the bolt. Unfortunately 12.9 type bolts have a continuous thread along the shaft and as such the level of coat weight was indicated instead of coating thickness. The values for bolts 8.8 and 10.9 refer to values considering three consecutive tightenings of each tested bolt; for the bolt 12.9 data refer to one tightening (indicated with 1 T) and three tightenings (indicated with 3 T). The specific pigment used was a titanium dioxide having a primary mean particle size of 10 nm. The product used is produced under the Trade Mark Hombitec? RM400 by Sachtleben Chemie GmbH, in powder form.

(68) The compositions tested are indicated in Table 7a.

(69) TABLE-US-00023 TABLE 7a Formulation 34 35 Butylacetate 55.35 56.86 n-butanol 15.64 16.07 Epoxy resin 10.06 10.34 Si-resin 2.91 2.99 Phenolic resin 3.36 3.05 Phosphoric acid 0.19 0.20 Polyamide thickener 3.03 2.85 Solid lubricant PTFE-wax mix 2.33 2.41 hydrocarbon wax 0.78 0.80 TiO.sub.2 (Hombitec? RM400) 5.37 3.45 Methyltrimethoxysilane 0.96 0.99

(70) TABLE-US-00024 TABLE 7b Coating Bolt Formulation Thickness (?m) Type COF.sub.tot COF.sub.thread COF.sub.head 35 7.7 8.8 0.109 (0.019) 0.108 (0.023) 0.109 (0.034) 34 12.9 8.8 0.111 (0.022) 0.125 (0.030) 0.103 (0.029) 35 11.7 10.9 0.089 (0.018) 0.109 (0.049) 0.079 (0.029) 34 15.9 10.9 0.085 (0.028) 0.115 (0.059) 0.069 (0.017) 35 0.044 12.9 - 0.099 (0.069) 0.086 (0.075) 0.107 (0.071) 3T 35 0.044 12.9 - 0.086 (0.022) 0.081 (0.015) 0.088 (0.026) 1T 34 0.054 12.9 - 0.084 (0.038) 0.071 (0.035) 0.091 (0.052) 3T 34 0.054 12.9 - 0.076 (0.019) 0.072 (0.014) 0.079 (0.024) 1T

(71) In Table 7b 1 T means one tightening and 3 T means 3 tightenings. The TiO.sub.2 results in Table 7b results are showing, that this pigment had a favourable influence on the coefficient of friction (COF) and scatter in particular on threads (see results of 12.9 bolts and three tightenings).