Lubricant for iron powder

Abstract

There is provided a premix of iron powder comprising iron powder and from 0.3 to 1 wt. % of a lubricant. The lubricant comprises from 40 to 84 wt. % of an amide lubricating agent; from 15 to 60 wt. % of a flame retardant; and from 1 to 5 wt. % of fumed silica nanoparticles. The fumed silica nanoparticles are a coating that encapsulates the iron powder.

Description

LUBRICANT FOR IRON POWDERCROSS-REFERENCE TO RELATED APPLICATION

[0001] The present disclosure is claiming priority from U.S. Provisional Application No. 63 / 736,905 filed December 20, 2024, the content of which is hereby incorporated by refence in its entirety.

[0002] This disclosure relates to the field of lubricants for iron powders and premixes comprising the lubricant and iron powders.BACKGROUND OF THE ART

[0003] The addition of lubricant to metal powder mixes is essential for enhancing the compressibility of the premix during compaction and improving the ejection of parts by increasing lubricity between particles and between particles and the die wall. However, incorporating lubricant into the premix can lead to flow issues during the transfer to the die. Current commercial lubricants also present inconsistencies. For instance, a premix that exhibits flow problems under high shear stress during preparation may behave differently when blended using tumbling blenders. Additionally, certain premixes with commercial lubricants experience flow issues when a binder is injected into the mix, resulting in a lack of flow. Furthermore, some premixes face flow challenges under hot and humid conditions. Therefore, there is a need for an improved lubricant that ensures consistent and rapid flow, maintains crucial properties such as compressibility, and provides a clean surface, regardless of the iron powder composition or manufacturing method used.SUMMARY

[0004] In one aspect, there is provided a premix of iron powder comprising: iron powder and from 0.3 to 1 wt. % of a lubricant, wherein the lubricant comprises from 40 to 84 wt. % of an amide lubricating agent; from 15 to 60 wt. % of a flame retardant; and from 1 to 5 wt. % of fumed silica nanoparticles; wherein the fumed silica nanoparticles are a coating that encapsulates the iron powder.

[0005] In some embodiments, the amide lubricating agent is a monoamide or a bisamide organic fatty acid. In some embodiments, the monoamide is of formula I:wherein each R is H or C10-C25 linear alkyl or alkylene but at least one R is C10-C25 linear alkyl or alkylene.

[0006] In some embodiments, the bisamide is of formula II:wherein n is an integer of from 1 to 6 and each R is H or C10-C25 linear alkyl or alkylene but at least one R is C10-C25 linear alkyl or alkylene.

[0007] In at least some embodiments, the amide lubricating agent is selected from ethylene bis stearamide (EBS), oleamide, erucamide, behenamide, N-Oleylpalmitamide, or a combination thereof.

[0008] In at least some embodiments, the amide lubricant agent comprises EBS in a concentration of from 30 to 65 wt. %, and oleamide in a concentration of from 10 to 60 wt. %

[0009] In at least some embodiments, the flame retardant is a halogenated flame retardant, a phosphorous based flame retardant, an inorganic flame retardant, a nitrogen based flame retardant, a calcium borate or a silicone-based flame retardant.

[0010] In at least some embodiments, the flame retardant is hexabromocyclododecane, decabromodiphenyl ether, ammonium phosphate, aluminum hydroxide, zinc borate, melamine, melamine phosphate, melamine cyanurate or ammonium polyphosphate.

[0011] In at least some embodiments, the flame retardant is in a concentration of from 15 to 40 wt. % in the lubricant.

[0012] In at least some embodiments, the iron powder has a particle size defined by a D50 of from 50 to 150 pm.

[0013] In at least some embodiments, the lubricant further comprises polyethylene wax in a concentration of from 10 to 45 wt. %.

[0014] In at least some embodiments, the lubricant further comprises erucamide in a concentration of from 15 to 25 wt. %.

[0015] In at least some embodiments, the iron powder is an iron alloy comprising Cu, C, MnS, and Ni.

[0016] In a further aspect, there is provided a lubricant comprising: from 40 to 84 wt. % of an amide lubricating agent; from 15 to 60 wt. % of a flame retardant; and from 1 to 5 wt. % of fumed silica nanoparticles.

[0017] In at least some embodiments, the amide lubricating agent is a monoamide or a bisamide organic fatty acid.

[0018] In at least some embodiments, the monoamide is of formula I:wherein each R is H or C10-C25 linear alkyl or alkylene but at least one R is C10-C25 linear alkyl or alkylene.

[0019] In at least some embodiments, the bisamide is of formula II:wherein n is an integer of from 1 to 6 and each R is H or C10-C25 linear alkyl or alkylene but at least one R is C10-C25 linear alkyl or alkylene.

[0020] In at least some embodiments, the amide lubricating agent is selected from ethylene bis stearamide (EBS), oleamide, erucamide, behenamide, N-Oleylpalmitamide, or a combination thereof.

[0021] In at least some embodiments, the amide lubricant agent comprises EBS in a concentration of from 30 to 65 wt. %, and oleamide in a concentration of from 10 to 60 wt. %

[0022] In at least some embodiments, the flame retardant is a halogenated flame retardant, a phosphorous based flame retardant, an inorganic flame retardant, a nitrogen based flame retardant, a calcium borate or a silicone-based flame retardant.

[0023] In at least some embodiments, the flame retardant is hexabromocyclododecane, decabromodiphenyl ether, ammonium phosphate, aluminum hydroxide, zinc borate, melamine, melamine phosphate, melamine cyanurate or ammonium polyphosphate.

[0024] In at least some embodiments, the flame retardant is in a concentration of from 15 to 40 wt. % in the lubricant.

[0025] Many further features and combinations thereof concerning the present improvements will appear to those skilled in the art following a reading of the instant disclosure.DESCRIPTION OF THE DRAWINGS

[0026] FIG. 1 is a bar graph showing the Hall flow and Gustavsson flow for a commercial lubricant and two exemplary lubricants, with mix #1 blended using ploughshare blender (Table 1).

[0027] FIG. 2 is a graph showing the die filling in function of the shoe speed for a commercial lubricant and two exemplary lubricants, with mix #1 blended using ploughshare blender (Table 1).

[0028] FIG. 3 is a graph showing the die filling in function of the shoe speed for a commercial lubricant and two exemplary lubricants, with mix #2 blended using ploughshare blender (Table 1).

[0029] FIG. 4 is a graph showing the die filling in function of the shoe speed for a commercial lubricant and two exemplary lubricants, with mix #2 modified to have 0.6% lubricant instead of 0.65% blended using ploughshare blender (Table 1).

[0030] FIG. 5 is a graph showing the cohesive index in function of the drum speed for a commercial lubricant and two exemplary lubricants, with mix #1 blended using ploughshare blender (Table 1).

[0031] FIG. 6 is a graph showing the cohesive index in function of the drum speed for four commercial lubricants A, B, E and D and one exemplary lubricant, with mix #5 blended using double cone blender (Table 1).

[0032] FIG. 7 is a graph showing the cohesive index in function of the drum speed for four commercial lubricants A, B, E and D and one exemplary lubricant, with mix #3 blended using double cone blender (Table 1).

[0033] FIG. 8 is a bar graph showing the flow for four commercial lubricants A, B, E and D and exemplary lubricants, with mix #5 blended using double cone blender.

[0034] FIG. 9 is a bar graph showing the flow for four commercial lubricants A, B, E and D and exemplary lubricants, with mix #3 (Table 1) (NF = no flow) blended using double cone blender.

[0035] FIG. 10 is a bar graph showing the Gustavsson flow for a commercial lubricant “A” and an exemplary lubricant with mix #2 (Table 1) for each lubricant the bar on the left is measured at 24°C relative humidity 41 % and the bar on the right is measured at 30°C relative humidity 85% (NF = no flow) blended using double cone blender.

[0036] FIG. 11 is a bar graph showing the Hall flow for a commercial lubricant “A” and an exemplary lubricant with mix #2 (Table 1) for each lubricant the bar on the left is measured at 24°C relative humidity 41 % and the bar on the right is measured at 30°C relative humidity 85% (NF = no flow) blended using double cone blender.

[0037] FIG. 12 is a bar graph showing the Hall flow for four commercial lubricants A, B, E and D and an exemplary lubricant with mix #3 (Table 1) for each lubricant the bar on the left is measured at 24°C relative humidity 41% and the bar on the right is measured at 30°C relative humidity 85% (NF = no flow) blended using double cone blender.

[0038] FIG. 13 is a bar graph showing the green density for four commercial lubricants A, B, E and D and three exemplary lubricants (Lub 1 , 3 and 5) with mix #5 (Table 1) blended using double cone blender, for each lubricant the bar on the left is measured at 50°C and the bar on the right is measured at 80°C.

[0039] FIG. 14 is a bar graph showing the green density for commercial lubricants A, B, E and D and three exemplary lubricants (Lub 1 , 3 and 5) with mix #3 Table 1 (Binder A) blendedusing double cone blender, for each lubricant the bar on the left is measured at 50°C and the bar on the right is measured at 80°C.

[0040] FIG. 15 is a bar graph showing the green density for commercial lubricants A, B, E and D and three exemplary lubricants (Lub 1 , 3 and 5) with mix #3 Table 1 (Binder B) blended using double cone blender, for each lubricant the bar on the left is measured at 50°C and the bar on the right is measured at 80°C.

[0041] FIG. 16 is a bar graph showing the green density for commercial lubricants A, B, E and D and three exemplary lubricants (Lub 1 , 3 and 5) with mix #3 Table 1 (Binder A) blended using double cone blender, for each lubricant the bar on the left is measured at 50°C and the bar on the right is measured at 80°C.

[0042] FIG. 17 is a bar graph showing the green strength for commercial lubricants A, B, E and D and three exemplary lubricants (Lub 1 , 3 and 5) with mix #3 Table 1 (Binder B) blended using double cone blender, for each lubricant the bar on the left is measured at 50°C and the bar on the right is measured at 80°C.

[0043] FIG. 18 is a graph showing the stripping shear stress for commercial lubricant C and an exemplary lubricant (Lub 3) with mix 2 (Table 1).

[0044] FIG. 19 is a graph showing the sliding shear stress for commercial lubricant C and an exemplary lubricant (Lub 3) with mix 2 (Table 1).

[0045] FIG. 20 is a graph showing the ejection shear stress for commercial lubricant C and an exemplary lubricant (Lub 3) with mix 2 (Table 1).

[0046] FIG. 21 is a graph showing the stripping shear stress for commercial lubricant C and an exemplary lubricant (Lub 3) with mix 5 (Table 1).

[0047] FIG. 22 is a graph showing the sliding shear stress for commercial lubricant C and an exemplary lubricant (Lub 3) with mix 5 (Table 1).

[0048] FIG. 23 is a graph showing the ejection shear stress for commercial lubricant C and an exemplary lubricant (Lub 3) with mix 5 (Table 1).DETAILED DESCRIPTION

[0049] The present disclosure provides a lubricant for iron powders that enables reliable and swift powder flow while preserving iron alloy properties, irrespective of premix formulation or manufacturing methods. The properties of powder metallurgy (PM) premixes are highly influenced by the choice of lubricants, which significantly impact flow characteristics, as well as the resulting green and sintered properties. Environmental factors during critical stages such as mixing, transportation, storage, and part manufacturing, along with blending techniques (e.g., ploughshare or tumbling blenders), profoundly affect powder flowability. An effective lubricant should maintain PM premix flow properties even under conditions of elevated temperature, humidity, or high shear stress during blending.

[0050] The present lubricant achieves multiple advantages, for example high compressibility and stable flow in the premix to ensure flowability and compressibility. The lubricant also ensures desirable mechanical properties while also providing a clean surface after sintering. The wide applicability of the present lubricants on various composition of iron powders is also an advantage since it allows reducing inventory space that would have been held by multiple lubricants that cover a different range of iron powder compositions.

[0051] The lubricant of the present disclosure achieves these advantages, at least in part, thanks to the inclusion of nanoparticles of fumed silica. The nanoparticles of fumed silica are combined with a flame retardant and an amide lubricating agent to form the lubricant. The combination of all three components enables the desirable properties and advantages discussed herein for the lubricant of the present disclosure.

[0052] Amide lubricating agents are generally organic fatty acids with one or more amide groups. In some embodiments, the amide lubricating agent is a monoamide or a bisamide. In one example, the mono-amide is of formula I:

[0053] where each R is H or C10-C25 linear alkyl or alkylene but at least one R is C10-C25 linear alkyl or alkylene. The alkylene can have one or two C=C bonds. In one example, the bisamide is of formula II:

[0054] where n is an integer of from 1 to 6 and each R is H or C10-C25 linear alkyl or alkylene but at least one R is C10-C25 linear alkyl or alkylene. The alkylene can have one or two C=C bonds. In some embodiments, in formula I and / or formula II, the linear alkyl or alkylene is C13-C23 or preferably C15-C21. In some embodiments, n is an integer selected from 2, 3, or 4, and is preferably 2.

[0055] In some embodiments, the amide lubricating agents are selected from ethylene bis stearamide (EBS), oleamide, erucamide, behenamide, N-Oleylpalmitamide, or a combination thereof. In a preferred embodiment, the amide lubricating agent is a combination of EBS and oleamide and optionally erucamide.

[0056] The amide lubricating agent is provided in the lubricant formulation in a concentration of a from 40 to 84 wt. %. In some embodiments, the amide lubricating agent is provided in a concentration of from 45 to 84 wt. %, from 50 to 84 wt. %, from 55 to 84 wt. %, from 60 to 84 wt. %, from 65 to 84 wt. %, from 50 to 80 wt. %, from 55 to 80 wt. %, or from 60 to 80 wt. %. In some embodiments, the amide lubricating agent comprises both EBS and oleamide. In such embodiments, the EBS can be present in a concentration of from 30 to 65 wt. %, and the oleamide can be present in a concentration of from 10 to 60 wt. %, although the total combined concentration of EBS and oleamide is within the ranges provided for the total concentration of the amide lubricating agent. In at least some embodiments, the EBS has a concentration of from 35 to 60 wt. % and the oleamide has a concentration of from 15 to 40 wt. %. In some embodiments, the amide lubricating agent comprises EBS, oleamide and erucamide. In such embodiments, the erucamide can be present in a concentration of from 15 to 25 wt. % although the total combined concentration of EBS, erucamide and oleamide is within the ranges provided for the total concentration of the amide lubricating agent. Without wishing to be bound by theory, in some embodiments, the EBS has a molecular weight of more than 600 g / mol as it provides a desirable increase in green strength.

[0057] The flame retardant for the lubricant of the present disclosure can be a halogenated flame retardant, a phosphorous based flame retardant, an inorganic flame retardant, a nitrogen based flame retardant (e.g. polyamide flame retardants), a calcium borate or a silicone-basedflame retardant. The halogenated flame retardants are for example hexabromocyclododecane or decabromodiphenyl ether. The phosphorous-based flame retardant can for example be ammonium phosphate. The inorganic flame retardants can for example be aluminum hydroxide or zinc borate. The nitrogen-based flame retardant is for example melamine, melamine phosphate, melamine cyanurate or ammonium polyphosphate. The flame retardant of the present disclosure is preferably selected in powder form that does not melt or decompose at high temperature. The flame retardant is for example provided in a concentration of from 15 to 60 wt. % in the lubricant, preferably from 15 to 50 wt. %, from 15 to 40 wt. %, or from 15 to 30 wt. %.

[0058] The present lubricant formulation combines an amide lubricating agent such as a monoamide or bisamide wax and a flame retardant. This combination provides a desirable effect on the performance of the lubricant. The flame retardant designed to decompose at temperatures exceeding 300°C and in conjunction with the utilization of amide waxes provides desirable flowability and properties even at high temperatures.

[0059] Importantly, the lubricant incorporates fumed silica nanoparticles which coat the lubricant formulation. The fumed silica nanoparticles can be included in concentration of from 1 to 5 wt. %, for example from 2 to 5 wt. %, from 2.5 to 5 wt. %, from 1 to 4 wt. %, from 1 to 3.5 wt. %, or from 2 to 4 wt. %. The fumed silica nanoparticles can have a diameter of from 1 nm to 500 nm, from 10 nm to 200 nm or from 10 nm to 100 nm. Generally, the particle size of the lubricant can be in the range of from 2 to 80 pm.

[0060] The fumed silica nanoparticles act as a coating agent for other particles of the lubricant and the iron powder. Due to its extremely small particle size (in the nano range) and high surface area, fumed silica nanoparticles have a strong tendency to adhere to the surfaces of other larger particles (e.g. micron range), forming a thin layer or coating around them. In embodiments where the flame retardant or other component of the lubricant is also in the nano range similarly to the fumed silica particles, then the flame retardant can also form part of the coating.

[0061] Optional additives can also be provided in the lubricant composition such as polyethylene wax and high-density polyethylene wax. The polyethylene wax can be provided in a concentration of from 10 to 45 wt. % in some embodiments.

[0062] The present lubricant composition is suitable for iron powders of various compositions. The iron powders can for example be iron alloys comprising up to 2 wt. % of Cu, C, MnS, Zn, Cr, Si, Mo, and / or Ni, and optionally a binder at a concentration of up to 1 wt. %. Exemplary ironpowder composition include: (1) 1.5-3.9 wt. % Cu and 0.3-0.6 wt. % C, (2) 1.5-3.9 wt. % Cu and 0.6-0.9 wt. % C, or (3) 0.4-0.7 wt. % C, 1.7-2.0 wt. % Ni, 0.45-0.6 wt. % Mo, and 0.05-0.3 wt. % Mn.

[0063] To form a premix, the lubricant is combined with the iron powder. The iron powder generally has a particle size average of from 50 to 500 pm, from 50 to 250 pm or from 50 to 150 pm. In some embodiments the iron powder particles have a D50 in the range of from 50 to 150 pm. The lubricant is mixed with the iron powder at a concentration generally of from 0.3 to 1 wt. %. The lubricant influences powder attributes such as flow, apparent density, and green and sintered properties.EXAMPLE

[0064] Different lubricants have been utilized in lubricants the premix formulas 1-8 outlined in Table 1.

[0065] Five different commercial lubricants labelled A, B, C, D and E were used as comparison points for the present lubricants. These were respectively a mixture of different amides, Kenolube™, EBS, SUPERLUBE™ 3 and CAPLUBE L™. The present lubricants were labeled “Lub 1”, “Lub 3” and “Lub 5”. Lub 1 contained in weight percent 58.3% EBS, 19.4% oleamide, 19.4% polyethylene wax and 2.9% nanoparticles of fume silica. Lub 3 contained in weight percent 58.3% EBS, 19.4% oleamide, 19.4% of a flame retardant and 2.9% nanoparticles of fume silica. Lub 5 contained in weight percent 37.9% EBS, 34.95% oleamide, 24.27% of the flame retardant and 2.9% nanoparticles of fume silica. The Hall flow (HF) was compared between Lubs 1 , 3 and 5 and the commercial lubricants A-D (Fig. 1 and Table 1).

[0066] A die-filling device operating in parallel mode was utilized to examine the filling efficiency and stability of the powder mix when using various lubricants. The device, designed to uniformly distribute metal powder into die cavities, was tested at four different shoe speeds: 8, 12, 19.2, and 32 cm / sec. These speeds were selected to provide a comprehensive comparison across a range of conditions. The device functions by moving a spreader or shoe across the die cavity, ensuring an even distribution of the powder. By varying the shoe speeds, we aimed to assess the impact of different lubricants on the efficiency of the filling process and the stability of the powder mix within the die cavity. Figs. 2-4 illustrate how the premixes containing the present lubricants outperform the mix containing commercial A or C lubricants in uniformly distributing metal powder into die cavities, particularly at higher shoe speeds (19.2 and 32 cm / sec). The filling index was calculated using the formula (pF10 - pF4) / pF10, where F10 and F4 have volumes of 10 and 4 cm3, respectively. This ratio indicates the mass of powder in each cavity with the specified volume at different speeds. The shoe speeds were varied to assess the impact of different lubricants on the efficiency of the filling process and the stability of the powder mix within the die cavity.

[0067] Using the GranuDrum™ instrument, the powder mixture cohesion as a function of drum rotating speed was measured. In the GranuDrum™ experiment, a transparent drum cylinder was rotated around its axis while half-filled with a sample of powder. Powder rotation in the drum at various rotating speeds was recorded, and the cohesive index (shear / friction component of the flow) was calculated using mathematical simulation. Figs. 5-7 show that GranuDrum™ experiment aligned with those obtained using traditional flowmeters, as depicted in Figs. 8-9, respectively. Specifically, the premixes with the presently developed lubricants exhibited a lower cohesion index compared to those containing the commercially available lubricants (in both premix formulastested). This consistency across different measurement methods underscores the effectiveness of the present lubricants in reducing powder cohesion.

[0068] The presently developed lubricant formulations have undergone extensive testing across a range of metal powder premix formulations and manufacturing methods. The empirical findings unequivocally demonstrate that premixes incorporating the presently developed lubricant consistently exhibited significantly improved flow rates, regardless of the specific premix formulation or manufacturing process used. As shown in Figs. 10-12, the flow of the mixes with commercial lubricants was adversely affected by storage under hot and humid conditions. However, the flow of the premix containing Lub 3 remained unaffected, even in the same conditions. As shown in Figs. 13-17, the figures show that the green density that can be obtained by using the present lubricants compressed at 60 tsi at 50 °C and 80 °C. The higher the density, the more compressible is the powder. The higher green strength was obtained by the present high performance lubricants compared to the commercial lubricants. As shown in Figs. 18-23, the ejection performance analysis demonstrated that the lower the force the higher the lubricity.

[0069] Based on the present results it was observed that:• The addition of fumed silica nanoparticles improved flow (both Hall and Gustavsson flow),• Having more EBS in the formula resulted in better flow, however, compressibility and lubricity were adversely affected,• Having more flame retardant resulted in more die filling stability and compressibility,• Replacing the polyamide flame retardant with polypropylene or polyethylene wax resulted in less compressibility.

Claims

WHAT IS CLAIMED IS:

1. A premix of iron powder comprising: iron powder and from 0.3 to 1 wt. % of a lubricant, wherein the lubricant comprises from 40 to 84 wt. % of an amide lubricating agent; from 15 to 60 wt. % of a flame retardant; and from 1 to 5 wt. % of fumed silica nanoparticles; wherein the fumed silica nanoparticles are a coating that encapsulates the iron powder.

2. The premix of claim 1 , wherein the amide lubricating agent is a monoamide or a bisamide organic fatty acid.

3. The premix of claim 2, wherein the monoamide is of formula I:wherein each R is H or C10-C25 linear alkyl or alkylene but at least one R is C10-C25 linear alkyl or alkylene.

4. The premix of claim 2, wherein the bisamide is of formula II:wherein n is an integer of from 1 to 6 and each R is H or C10-C25 linear alkyl or alkylene but at least one R is C10-C25 linear alkyl or alkylene.

5. The premix of any one of claims 1 to 4, wherein the amide lubricating agent is selected from ethylene bis stearamide (EBS), oleamide, erucamide, behenamide, N- Oleylpalmitamide, or a combination thereof.

6. The premix of any one of claims 1 to 5, wherein the amide lubricant agent comprises EBS in a concentration of from 30 to 65 wt. %, and oleamide in a concentration of from 10 to 60 wt. %.

7. The premix of any one of claims 1 to 6, wherein the flame retardant is a halogenated flame retardant, a phosphorous based flame retardant, an inorganic flame retardant, a nitrogen based flame retardant, a calcium borate or a silicone-based flame retardant.

8. The premix of any one of claims 1 to 7, wherein the flame retardant is hexabromocyclododecane, decabromodiphenyl ether, ammonium phosphate, aluminum hydroxide, zinc borate, melamine, melamine phosphate, melamine cyanurate or ammonium polyphosphate.

9. The premix of any one of claims 1 to 8, wherein the flame retardant is in a concentration of from 15 to 40 wt. % in the lubricant.

10. The premix of any one of claims 1 to 9, wherein the iron powder has a particle size defined by a D50 of from 50 to 150 pm.

11. The premix of any one of claims 1 to 10, wherein the lubricant further comprises polyethylene wax in a concentration of from 10 to 45 wt. %.

12. The premix of any one of claims 1 to 11, wherein the lubricant further comprises erucamide in a concentration of from 15 to 25 wt. %.

13. The premix of any one of claims 1 to 12, wherein the iron powder is an iron alloy comprising Cu, C, MnS, and Ni.

14. A lubricant comprising: from 40 to 84 wt. % of an amide lubricating agent; from 15 to 60 wt. % of a flame retardant; and from 1 to 5 wt. % of fumed silica nanoparticles.

15. The lubricant of claim 14, wherein the amide lubricating agent is a monoamide or a bisamide organic fatty acid.

16. The lubricant of claim 15, wherein the monoamide is of formula I:wherein each R is H or C10-C25 linear alkyl or alkylene but at least one R is C10-C25 linear alkyl or alkylene.

17. The lubricant of claim 15, wherein the bisamide is of formula II:wherein n is an integer of from 1 to 6 and each R is H or C10-C25 linear alkyl or alkylene but at least one R is C10-C25 linear alkyl or alkylene.

18. The lubricant of any one of claims 14 to 17, wherein the amide lubricating agent is selected from ethylene bis stearamide (EBS), oleamide, erucamide, behenamide, N- Oleylpalmitamide, or a combination thereof.

19. The lubricant of any one of claims 14 to 18, wherein the amide lubricant agent comprises EBS in a concentration of from 30 to 65 wt. %, and oleamide in a concentration of from 10 to 60 wt. %.

20. The lubricant of any one of claims 14 to 19, wherein the flame retardant is a halogenated flame retardant, a phosphorous based flame retardant, an inorganic flame retardant, a nitrogen based flame retardant, a calcium borate or a silicone-based flame retardant.

21. The lubricant of any one of claims 14 to 20, wherein the flame retardant is hexabromocyclododecane, decabromodiphenyl ether, ammonium phosphate, aluminum hydroxide, zinc borate, melamine, melamine phosphate, melamine cyanurate or ammonium polyphosphate.

22. The lubricant of any one of claims 14 to 21 , wherein the flame retardant is in a concentration of from 15 to 40 wt. % in the lubricant.

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