Fouling resistant threaded fastener

Abstract

Examples of a fastener include threads and a thermoset epoxy coating covering the threads. The thermoset epoxy coating includes an internal lubricant. The thermoset coating, once cured on the threads, resists weld spatter and e-coat adhesion. The thermoset epoxy coating is Per- and polyfluoroalkyl substances (PEAS) free.

Description

FOULING RESISTANT THREADED FASTENERCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims priority of U.S. Provisional Patent Application 63 / 779,672 filed on March 28, 2025, the contents of which is hereby incorporated by reference in its entirety.FIELD OF THE DISCLOSURE

[0002] The present disclosure is related to threaded fasteners. More specifically, the present disclosure is related to threaded fasteners which resist fouling during manufacturing processes.BACKGROUND

[0003] Per- and polyfluoroalkyl substances (PFAS) have been extensively utilized in various industries, including fasteners for automotive and electronics industries, due to their unique chemical properties including resistance to water, oil, and heat. Despite their widespread use, PFAS are known for their environmental persistence and bioaccumulation, leading to significant health concerns. PFAS are often referred to as "forever chemicals" because they do not break down easily and can remain in the environment for an extended period. As a result, regulatory agencies worldwide have imposed stringent limits on the use of PFAS, prompting industries to seek methods to eliminate these substances from their manufacturing processes.

[0004] PFAS chemicals have been used to coat fastener threads to provide resistance to fouling of the threads due to byproduct or offshoot from other manufacturing process, particularly for resistance to weld spatter and electrocoating (e-coat) treatment. Welding processes cause the ejection of small, molten droplets from the weld pool which settle about the surrounding work area. E-coat treatment involves immersing a component in a water-based solution of paint particles, then applying a current to cause the paint particles to adhere to the metal surface. Both of these byproducts can foul the threads of a fastener, impeding the later threading of the fastener to ensure a secure hold by the fastener.

[0005] Consequently, fasteners with threading that can resist fouling without the use of PFAS would be an advantageous improvement over current fasteners.BRIEF DISCLOSURE

[0006] Examples of a fastener include threads and a thermoset epoxy coating covering the threads. The thermoset epoxy coating includes an internal lubricant. The thermoset coating, once cured on the threads, resists weld spatter and e-coat adhesion.

[0007] The following are additional statements of features which may be found in examples of the disclosed fastener and which may exist alone or combined with any other stated features.

[0008] The thermoset epoxy coating is Per- and polyfluoroalkyl substances (PFAS) free.

[0009] After exposure to weld spatter and e-coating processes the fastener exhibits substantially no weld spatter adhesion on the thermoset coating and substantially no e-coat adhesion on the thermoset coating. After exposure to weld spatter and e-coating processes the fastener exhibits no weld spatter adhesion on the thermoset coating and no e-coat adhesion on the thermoset coating.

[0010] The fastener exhibits a first-on torque of less than 3Nm as tested under IFI 543 with an M10 size assembly and a gun speed of 100 maximum RPM. The first-on torque may be less than 2 Nm. Optionally, the first-on torque may be less than 1 Nm. Optionally, the first-on torque may be less than 0.5 Nm. The first-on torque may be between 0.08 - 0.32 Nm.

[0011] The internal lubricant may be a wax. The internal lubricant may be a polyethylene (PE) wax. The internal lubricant may be a polypropylene (PP) wax. The internal lubricant may be a powdered wax. The internal lubricant may be present in an amount of 0.5% - 10.0% w / w. The fastener may be a nut and the threads are internally facing threads. The fastener may have externally facing threads. The fastener may further include a secondary coating applied over at least a portion of the thermoset epoxy coating after the thermoset epoxy coating has cured. The secondary coating may be a rust-preventative coating.

[0012] The thermoset epoxy coating and the internal lubricant are powered and applied to the fastener in a powdered form. The fastener may be heated in the application of the thermoset epoxy coating, optionally the fastener is heated after the application of the thermoset epoxy coating.

[0013] A two-part assembly includes the fastener as described in any of the examples above and a mating fastener. The two-part assembly exhibits a tension of between 10 - 36 kN atassembly may exhibit a thread coefficient of friction of between 0.06 - 0.16 between the fastener and the mating fastener. The thread coefficient of friction may be between 0.07-0.13. The coefficient of friction may be between 0.10-0.16. The thread coefficient of friction may be between 0.10-0.13.BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 depicts an example of a threaded nut with a fouling resistant coating.

[0015] Figures 2A-2C depict examples of a threaded fastener of the present disclosure.

[0016] Figures 3A-3C depict a comparative fastener not within the scope of the present disclosure.

[0017] Figures 4A and 4B depict an example of a weld spatter test installation.

[0018] Figures 5A and 5B depict an example of a fastener removal test.DETAILED DISCLOSURE

[0019] Disclosed herein are PFAS free coatings and fasteners including such coating to provide fouling resistant threads, particularly threads resistant to fouling by weld spatter or e-coat treatment. Figure 1 depicts an example of a fastener 10, more specifically a nut, as described herein. The fastener 10 includes threads 12. It will be recognized that a fastener of a nut has internally facing threads as depicted in Fig. 1, while a fastener exemplarily in the form of a screw or bolt had externally facing threads, for example configured to mate with the internally facing threads of a nut. While the specific example of internally facing threads are used herein, it will be recognized that the present disclosure similarly applies to fasteners with externally facing threads, such as a screw or bolt.

[0020] The fastener 10 further may include weld projections 14, the weld projections providing additional surface upon which the fastener 10 may be welded to part of a larger structure. In one example, the fastener 10 may be welded to a body or frame of a larger structure, for example, an automotive, industrial, or agricultural vehicle. Further components may be secured to the body or frame thereof with bolts having a screw fit to the fastener 10.

[0021] As will be described in further detail herein, the fastener 10 includes a coating material 16 that is PFAS free and provides resistance to fouling of the threads by weld spatter ore-coat treatment. This coating 16 serves to prevent the build-up of post applied primers, paints, and weld spatter on the threads 12 of the fastener.

[0022] As described herein the threads of the fastener are coated with a thermoset epoxy coating which includes an internal lubricant and provides both the above-noted features as well as others as described herein.

[0023] As will be noted in examples below, the thermoset epoxy coating is made from a powder, such as an epoxy powder, that is subsequently cured to form the thermoset coating. In examples discussed herein use heat curing, although it will be recognized that in other examples, the thermoset epoxy coating may be cured alone or in part using chemical reaction or irradiation. The coating may be made from a powder that includes an epoxy resin, one or more curing agents or hardeners, and the internal lubricant. In still further examples, the powder additionally includes a pigment. In examples, the internal lubricant is provided in an amount of 0.5%- 10% (w / w), or a non-zero amount <10% (w / w), <9% (w / w), <8% (w / w), <7% (w / w), <6% (w / w), <5% (w / w), <4% (w / w), <3% (w / w), or <2% (w / w) or other ranges as may be recognized by a person of ordinary skill in the art in view of the present disclosure. In examples, the thermoset epoxy includes a pigment and the pigment may be provided in an amount <5% (w / w), <4% (w / w), <3% (w / w), <2% (w / w), <1% (w / w), <0.5% (w / w), 0.5% - 2.5% (w / w), l%-2% (w / w), or other range amounts as may be recognized by a person of ordinary skill in the art in view of the present disclosure. In a non-limiting example, the pigment may include titanium dioxide. In other examples, the pigment may be organic, inorganic, or the pigment may contain a mixture of organic and inorganic materials.

[0024] In various examples, the thermoset coating comprises an epoxy material such as an epoxy resin material or polyepoxide material. The epoxy resin material of the thermoset coating may be reacted (cross -linked) either with itself through catalytic homopolymerization, or with a wide range of co-reactants including polyfunctional amines, acids (and acid anhydrides), phenols, alcohols and thiols. These co-reactants may be hardeners or curatives, and the cross-linking reaction may be referred to as “curing.” Suitable epoxy resin materials for the thermoset coating may include, but are not limited to, bisphenol A epoxy resin material (e.g., as produced by combining epichlorohydrin and bisphenol A to give bisphenol A diglycidyl ethers), bisphenol F epoxy resin material, epoxy phenol novolac material and epoxy cresol novolac material (e.g., as produced by reaction of phenols with formaldehyde and subsequent glycidylation withepichlorohydrin), aliphatic epoxy resin material (e.g., as produced by glycidylation of aliphatic alcohols or polyols), and glycidylamin epoxy resin material (e.g., as formed when aromatic amines react with epichlorohydrin).

[0025] In various examples, the thermoset coating is a cross-linked epoxy coating. The coating may be a fusion-bond epoxy coating. In some embodiments, the thermoset coating is made from a powder, such as an epoxy powder, that is subsequently cured / cross -linked to form the thermoset coating, while in others it is made from a liquid precursor. In various examples, the coating is made from a powder comprising an epoxy resin and one or more curing agents or hardeners. The curing agents or hardeners may consist of or comprise one or more amines (e.g. aromatic amines, aliphatic diamines), anhydrides, acids, phenols, alcohols and / or thiols. In some examples, the powders further comprise one or more fillers and / or one or more pigments, or other additional components. In examples, the epoxy powder is a cross-linked epoxy coating and may include a fusion bonded epoxy coating. Further examples of epoxy materials may include epoxy resins or polyepoxides, polyester or polyester resin material, polyurethane material, vulcanized rubber material, phenol-formaldehyde resin material such as Bakelite, melamine material, diallylphthalate (DAP) material, polyimide material, and cyanate ester or polycyanurate material.

[0026] In examples, the curing agents or hardeners may include one or more amines, anhydrides, acids, phenols, and / or alcohols.

[0027] In examples, the internal lubricant is provided as a component of the powdered epoxy applied to the fastener and subsequently cured. In examples, the internal lubricant includes one or more wax, including but not limited to polyethylene (PE) wax, paraffin wax, or carnauba wax.

[0028] In still further examples, the internal lubricant may include, but is not limited to natural or synthetic petroleum-based bases, a vegetable fast or oil, a polyolefin polymer, tungsten disulfide, silver, graphite, soapstone, a stearate, a dithiophosphonate. diatomaceous earth, nanoparticle-sized particles of carbon and / or silica, or a combination thereof.

[0029] As noted above, the internal lubricant is exemplarily provided in an amount between 0.5% - 10.0% w / w, or one of the other ranges as provided above. The internal lubricant is exemplarily a wax. In a non-limiting example, the internal lubricant may be Deuteron™ polypropylene (PP) micronized wax available from Deuteron GmbH. The internal lubricant may be exemplarily used in an amount of 0.5 - 10.0 % w / w, 1.0 - 10.0 % w / w, or 1.0 - 5.0% w / w. Inanother non-limiting example, the internal lubricant may be Ceraflour 1050 polyethylene (PE) micronized wax available from BYK-Chemie GmbH. The internal lubricant may be used exemplarily in an amount of 0.5 - 3.0% w / w or 0.9 - 3.0% w / w.

[0030] In examples, the thermoset epoxy coating that includes an internal lubricant, when cured onto the threads of the fastener has a substantially uniform thickness of between about 0.001 - 0.008 inches (e.g. 30 pm - 200 pm). In still further examples, the coating has a substantially uniform thickness of about 50 pm. In still further examples, the coating has a thickness of one or more of 40 pm - 60 pm (0.0016 - 0.0024 inches), 45 pm - 55 pm (0.0018 - 0.0022 inches), 40 pm - 100 pm (0.0016 - 0.0039 inches), 50 pm - 80 pm (0.0020 - 0.0032 inches), 50 pm - 100 pm (0.0020 - 0.0039 inches), 40 pm - 130 pm (0.0016 - 0.0051 inches), 60 pm - 90 pm (0.0024 - 0.0035 inches), 15 pm - 150 pm (0.0006 - 0.0059 inches)or 100 pm - 150 pm (0.0039 - 0.0059 inches). In examples, substantially uniform thickness may mean that 2G and / or 3G values of coating thickness are within a range specified above. In other examples, substantially uniform thickness may mean that 2G and / or 3G values of coating thickness are within + / - 5pm, + / - 10pm, + / - 15pm, + / - 20pm.

[0031] Applying a powered coating like the one described above to internally threaded fasteners, such as nuts, provides additional challenges since, by intent, the coating prevents adhesion of e-coat treatment, which serves to provide rust and / or corrosion resistance to the rest of the structure, including in instances, the rest of the fastener besides the threads, therefore special considerations must be made for the application of the coating. In one example, the coating may be applied according to the apparatus and method for selectively applying powder coatings onto internally threaded fasteners as described in US 9829031, which is incorporated herein by reference in its entirety.

[0032] The thermoset epoxy coating as described above is exemplarily applied as a powder to the fastener to be coated. The application process may be a post-heat material coating process whereby the material is applied to the fastener and then heated to the curing and / or hardening temperature. The application process may further be a pre-heat coating process whereby the fastener is heated to the target temperature and then the powder of the thermoset epoxy coating is applied to the heated fastener threads.

[0033] In examples, the thermoset epoxy coating as described above is a rapid-cure thermoset coating, in such examples, the thermoset epoxy coating may cure in about one minuteor less when the coating material is in contact with the metal article and exposed to added heat, for example with the use of an induction heater. In non-limiting examples, the coating material cures in approximately thirty seconds or less. In further examples, the coating material cures in less than one minute, between thirty seconds and a minute, or less than thirty seconds when exposed to a temperature between about 350° F and 475° F. In still other examples, the coating material cures in less than one minute, between thirty seconds and a minute, or less than thirty seconds when exposed to a temperature between about 400° F and 450° F, between about 420° F and 430° F, or about 425° F.

[0034] The fastener with the thermoset epoxy coating composition including an internal lubricant further meets various performance requirements, including weld spatter resistance, e-coat resistance, free hand torque, thread coefficient of friction, and tension. Details regarding these performance requirements are provided herein.

[0035] Weld spatter resistance was evaluated and tested using the following procedure. Figures 4A and 4B depict a test fixture 20 for evaluation of weld spatter resistance. The test fixture 20 includes around steel mechanical tube 22, exemplarily having a 4.5 inch diameter. The tube 22 is supported in the concave opening of a piece 24 of angle iron welded to low carbon steel blocks 26. The tube 22 is grounded. This assembly positions the tube 22 above a sample placement area 28 on a non-metallic fire resistant sample support 30. A standard arc welder with a 1 / 8 inch diameter 6013 general purpose electrode 34 is held in an electrode clamp 36 and the arc welder is set to an output of 130 amps. The electrode 34 is held at an approximate 30° angle from vertical and contacted with the tube 22 at a contact point 38 which is the tangent point for a radius at 90° from the center point of the tube 22. The sample support 30 elevates one or more sample part(s) 32 placed in the sample placement area 28 to a height with the top of the sample part(s) 50mm from the contact point 38. A minimum of two back-and-forth passes are made along a line of contact 40 parallel to the sample placement area 28 above the sample part(s) and for a duration of no more than 10 seconds. The passes of the electrode 34 along the contact point 38 creates a shower of arc spatter 42 down onto the product samples(s) 32 on the sample placement area 28. As the contact point 38 accumulates electrode material build up, the tube 22 may be rotated in the direction of arrow 44 to expose fresh tube material for electrode contact during continued tests / testing.

[0036] After this test, the sample part(s) are evaluated for weld spatter adhesion on the threads of the part. Figures 2A-2C are pictures depicting an example of the disclosed fastener, while Figures 3A-3C are pictures depicting an example of an alternative fastener with the threads coated with a PFAS-free coating outside of the present disclosure for comparison. Figure 2A depicts the example disclosed fastener prior to testing. Figure 3A depicts the comparative fastener prior to testing. Figure 2B depicts the example disclosed fastener after the above weld spatter test. Visual inspection reveals that there is no weld spatter adhered to the threads coated with a thermoset epoxy composition with an internal lubricant, thus passing this test. Notably, there is an instance of weld spatter adhered outside of the threads where the fastener was not coated. This is compared to Figure 3B which depicts the comparative example after the above weld spatter test. Weld spatter is clearly seen on the threads coated with the comparative coating, thus failing this test. A passing test has no or substantially no weld spatter adhering to the coated threads after performance of the above test. Substantially no weld spatter as used herein may permit weld spatter that is of a small size such as not to be visually perceptible, or weld spatter that does not extend through the coating to adhere to the underlying fastener metal, or weld spatter does not otherwise impair the mechanic al / functional performance tests detailed below.

[0037] E-coat resistance was tested by visual inspection after subjecting the tested fasteners to an e-coat process. The following e-coat process was used in performing the evaluation below. The sample parts are first rinsed and prepared for testing under a standard part preparation procedure. The sample parts are wired individually using 18ga copper wire. The individually wired parts are immersed in a bath of e-coat solution, exemplarily PPG ED6061C solution. The solution is agitated and heated to a minimum of 90 °F. A recommended voltage between 190V and 250V is applied and the current is allowed to drop to 0.5 A on a cycle time of 2-3 seconds, using a DC Darrah electric rectifier power source. The sample parts are removed from the bath and thoroughly rinsed with water and dried using light compressed air. The sample parts are then baked in a laboratory oven at approximately 350°F for 25-30 minutes. The sample parts are removed from the oven and allowed to cool for 15-20 minutes before visual inspection. Upon visual inspection no or substantially no e-coat material should be present on the coated threads. In the images, the coating is light and the e-coat is dark (black). Figure 2C depicts the example disclosed fastener after the e-coat process whereby it is visible that the coated threads are maintained with the light coating (compare to Fig. 2A), without adhesion of the dark e-coat, thus passing this test. This iscompared against the comparative fastener in Figure 3C, whereby it is visible that dark e-coat is present on the threads, thus failing this test.

[0038] Thread coatings further can have a significant impact on torque required to achieve a particular result or clamping force. Coating thickness, adhesion, and composition may all impact the resulting torque. The disclosed fastener with the thermoset epoxy coating composition including an internal lubricant further was tested in an assembly of the coated fastener and a corresponding uncoated fastener, for example an assembly of a coated fastener as described herein as a nut and an uncoated threaded bolt. The disclosed fastener meets a prevailing-in or first-on torque of 2Nm or less for an MIO standard dimensioned fastener assembly, recognizing that such values are dependent in part upon fastener diameter where torque (T)= KDP, where K is the torque coefficient, D is the fastener diameter, P is the clamping force. Torque coefficient is exemplarily measured according to the ISO 16047:2005 test standard. The first-on torque may be evaluated to IFI 543 except with a gun speed of 100 RPM maximum. In examples the first-on torque of an assembly using the coated fastener as described herein is less than 3Nm, less than 2Nm, less than 1 Nm, or less than 0.5 Nm. In still further examples the thermoset epoxy coating as described herein results in a coated fastener which exhibited an average first-on torque of 0.20 Nm across the samples tested, with a standard deviation of 0.12 Nm. Therefore, in that test a majority of the tested coated fasteners exhibited a first-on torque between 0.08 and 0.32 Nm. It has been observed that weld spatter adhesion adversely affects first-on torque performance, therefore as noted above, a further indication of substantially no weld spatter adhesion is a first-on torque within the above disclosed ranges.

[0039] The disclosed fastener with the thermoset epoxy coating composition including an internal lubricant was further tested for thread coefficient of friction in the assembly of the coated fastener and a corresponding uncoated fastener, for example an assembly of a coated fastener as described herein as a nut and an uncoated threaded bolt. Coefficient of friction is a dimensionless value, but corresponds to the force that must be applied to properly tighten or torque a component of an assembly to a certain value. It represents the friction that is exhibited as the assembly is tightened. In examples, an assembly with the disclosed fastener having the threads coated in a thermoset epoxy having an internal lubricant must have a thread coefficient of friction between 0.06 - 0.16, 0.06 - 0.13. 0.07-0.13. 0.07-0.10. or 0.10 - 0.16. In a still further example, the threadcoefficient of friction is between 0.10 - 0.13. The thread coefficient of friction is exemplarily measured according to the ISO 16047:2005 test standard.

[0040] The disclosed fastener with the thermoset epoxy coating composition including an internal lubricant further was tested in an assembly of the coated fastener and a corresponding uncoated fastener (e.g. a steel or stainless steel), for example an assembly of a coated fastener as described herein as a nut and an uncoated threaded bolt. The disclosed fastener meets a tension (or clamping force P) of between 10-36kN or between 16-36kN for an M10 standard dimensioned fastener assembly at 40 Nm of torque, recognizing that such values are dependent in part upon fastener diameter where torque (T)= KDP, where K is the torque coefficient, D is the fastener diameter, P is the clamping force. Tension in this manner is exemplarily measured according to the ISO 16047:2005 test standard. The tension may further be measured according to TO-925 wherein IFI 543 is followed except that gun speed is 100 RPM maximum. Samples are exemplarily torqued according to IFI 543 and the tension measured to be between 10-36kN.

[0041] Given the specification above, the resulting fastener cannot include any secondary coatings over the thermoset epoxy coating as described above which detract from performance in the above tests. However, it has been found that in some use cases a secondary coating of a rust-preventative material is advantageous, however, any such secondary coating may not cause the fastener to fail any of the above performance standards. Secondary coatings of rust preventatives including, but not limited to, NC-3150, Castrol Rustilo DWX 22, and Castrol Rustilo DWX 30 may be used as a secondary coating while still maintaining passing performance of the above tests.

[0042] In addition to the performance metrics specified above, thermoset epoxy coating of the fastener is additionally desired to remove from the coated threads under a standard tightening friction. This material removal enables a metal-to-metal connection in the resulting threaded assembly constructed using a thermoset epoxy coated fastener as described herein. Such metal-to-metal contact may promote conductivity between the components of the assembly. A passing evaluation of this specification provides bare metal on the threads upon a visual inspection after a threading test as described herein. An assembly was formed using a thermoset epoxy coated fastener as described herein and a mating threaded fastener constructed of uncoated metal. The assemblies were exemplarily coated M10 steel weld nuts and M10 plain hex cap screws with M10 square washers. The assembly was tightened to 75% of the proof load per ISO 16047. The assembly was then un-tightened to the disassembled condition and the threads visually inspectedfor removal of the coating. A passing test exhibits exposure of the underlying metal on the front or prevailing side of the threads in the direction from which the screw was inserted into the nut. Figures 5A and 5B comparatively show a front side of the nut with the underlying metal (dark against the light coating on the threads) exposed in a positive removal test while the backside of the same nut retains the thermoset epoxy coating as described herein.

[0043] Citations to several references are made herein. The cited references are incorporated by reference herein in their entireties. In the event that there is an inconsistency between a definition of a term in the specification as compared to a definition of the term in a cited reference, the term should be interpreted based on the definition in the specification.

[0044] In the above description, certain terms have been used for brevity, clarity, and understanding. No unnecessary limitations are to be inferred therefrom beyond the requirement of the prior art because such terms are used for descriptive purposes and are intended to be broadly construed. The different systems and method steps described herein may be used alone or in combination with other systems and methods. It is to be expected that various equivalents, alternatives, and modifications are possible within the scope of the appended claims.

[0045] The disclosed functions, methods, or operational sequences are representative of exemplary architectures, environments, and methodologies for performing novel aspects of the disclosure. While, for purposes of simplicity of explanation, the methodologies included herein may be described as a series of acts, it is to be understood and appreciated that the methodologies are not limited by the order of acts, as some acts may, in accordance therewith, occur in a different order and / or concurrently with other acts from that shown and described herein. For example, those skilled in the art will understand and appreciate that a methodology can alternatively be represented as a series of interrelated states or events, such as in a state diagram. Moreover, not all acts illustrated in a methodology may be required for a novel implementation.

[0046] This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to make and use the invention. The patentable scope of the invention is defined by the claims and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.

Claims

CLAIMS1. A fastener comprising threads and a thermoset epoxy coating covering the threads, the thermoset epoxy coating comprising an internal lubricant wherein the thermoset coating, once cured, resists weld spatter and e-coat adhesion.

2. The fastener of claim 1, wherein the thermoset epoxy coating is Per- and polyfluoroalkyl substances (PFAS) free.

3. The fastener of claim 1 or 2 wherein after exposure to weld spatter and e-coating processes exhibits substantially no weld spatter adhesion on the thermoset coating and substantially no e-coat adhesion on the thermoset coating.

4. The fastener of claim 3, wherein after exposure to weld spatter and e-coating processes exhibits no weld spatter adhesion on the thermoset coating and no e-coat adhesion on the thermoset coating.

5. The fastener of any of the above claims, wherein the fastener exhibits a first-on torque of less than 3Nm as tested under IFI 543 with an MIO size assembly and a gun speed of 100 maximum RPM.

6. The fastener of claim 5, wherein the first-on torque is less than 2 Nm, optionally wherein the first-on torque is less than 1 Nm, and further optionally wherein the first-on torque is less than 0.5 Nm.

7. The fastener of claim 5, wherein the first on torque is between 0.08 - 0.32 Nm.

8. The fastener of any of the above claims wherein the internal lubricant is a wax.

9. The fastener of claim 8, wherein the internal lubricant is a polyethylene (PE) wax or a polypropylene (PP) wax.

10. The fastener of claim 8 or 9, wherein the internal lubricant is a powdered wax.

11. The fastener of any of claims 8-10, wherein the internal lubricant is present in an amount of 0.5% - 10.0% w / w.

12. The fastener of any of the above claims, wherein the fastener is a nut and the threads are internally facing threads.

13. The fastener of any of claims 1-11, wherein the threads are externally facing threads.

14. The fastener of any of the above claims, further comprising a secondary coating applied over at least a portion of the thermoset epoxy coating after the thermoset epoxy coating has cured.

15. The fastener of claim 14, wherein the secondary coating is a rust-preventative coating.

16. The fastener of any of the above claims, wherein the thermoset epoxy coating and internal lubricant are powdered and applied to the fastener in the powdered form.

17. The fastener of claim 16. wherein the fastener is heated in the application of the thermoset epoxy coating, optionally the fastener is heated after the application of the thermoset epoxy coating.

18. A two-part assembly comprising the fastener of any of the above claims and a mating fastener, wherein the two-part assembly exhibits a tension of between 10 - 36 kN at 40 Nm of torque as tested under the ISO 16047 standard for an M10 size assembly.

19. A two-part assembly comprising the fastener of any of claims 1-17 and a mating fastener, wherein the two-part assembly exhibits a thread coefficient of friction of between 0.06 -0.16 between the fastener and the mating fastener.

20. The two-part assembly of claim 19, wherein the thread coefficient of friction is between 0.07-0.13.

21. The two-part assembly of claim 19, wherein the thread coefficient of friction is between 0.10-0.16.

22. The two-part assembly of claim 21, wherein the thread coefficient of friction is between 0.10-0.13.

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