Solid lubricant bar

Abstract

A solid lubricant bar comprising hydrogenated castor oil or wax, expandable flake graphite, and copper. ATH, MDH, and zinc borate can also be added to the formulation to enhance fire retardancy and suppression.

Claims

1. A lubricant bar comprising by weight: a. hydrogenated castor oil ranging from 35% to 65%; b. expandable flake graphite ranging from 30% to 60%; and c. copper ranging from 5% to 15%.

2. The lubricant bar of claim 1, wherein the hydrogenated castor oil or wax is 60% by weight, the expandable flake graphite is 35% by weight, and the copper is 5% by weight.

3. The lubricant bar of claim 1, wherein the hydrogenated castor oil has a melting temperature between 60° C. and 80° C.

4. A lubricant bar comprising by weight: a. hydrogenated castor oil ranging from 40% to 60%; b. expandable flake graphite ranging from 30% to 50%; c. copper ranging from 3% to 5%; d. Alumina trihydrate ranging from 1% to 5%; e. magnesium hydroxide ranging from 1% to 5%; and f. zinc borate ranging from 2% to 5%.

5. The lubricant bar of claim 4, wherein the hydrogenated castor oil or wax is 50% by weight, the expandable flake graphite is 40% by weight, the copper is 5% by weight, the Alumina trihydrate is 2% by weight, and magnesium hydroxide is 3% by weight, and zinc borate is 3% by weight.

6. The lubricant bar of claim 4, wherein the hydrogenated castor oil has a melting temperature between 60° C. and 80° C.

7. A method for lubricating an interface between a support pad of a kiln shell and an inner diameter of a kiln tire, the method comprising the step of applying an effective amount of lubricant in the form of a lubricant bar comprising by weight: a. hydrogenated castor oil ranging from 35% to 65%; b. expandable flake graphite ranging from 30% to 60%; and c. copper ranging from 5% to 15%.

8. The method of claim 7, wherein the hydrogenated castor oil or wax 60% by weight, the expandable flake graphite is 35% by weight, and the copper is 5% by weight.

9. The method of claim 7, wherein the hydrogenated castor oil has a melting temperature between 60° C. and 80° C.

10. A method for lubricating an interface between a support pad of a kiln shell and an inner diameter of a kiln tire, the method comprising the step of applying an effective amount of lubricant in the form of a lubricant bar comprising by weight: a. hydrogenated castor oil ranging from 40%-60%; b. expandable flake graphite ranging from 30%-50%; c. copper ranging from 3%-5%; d. Alumina trihydrate ranging from 1%-5%; e. magnesium hydroxide ranging from 1%-5%; and f. zinc borate ranging from 2%-5%.

11. The method of claim 10, wherein the hydrogenated castor oil or wax is 50% by weight, the expandable flake graphite is 40% by weight, the copper is 5% by weight, the Alumina trihydrate is 2% by weight, and magnesium hydroxide is 3% by weight, and zinc borate is 3% by weight.

12. The method of claim 10, wherein the hydrogenated castor oil has a melting temperature between 60° C. and 80° C.

Description

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

(1) A solid lubricant bar in accordance with the present invention comprises the following formulation (1) by weight:

(2) Hydrogenated castor oil or wax 60%

(3) Expandable flake graphite 35%

(4) Copper powder 5%

(5) In the above formula, the hydrogenated castor oil or wax can range from 35%-65% by weight, the expandable flake graphite can range from 30%-60% by weight, and the copper can range from 5%-15% by weight.

(6) The specification for the hydrogenated castor wax MP 70 flakes is set forth in Table 1 below.

(7) TABLE-US-00001 TABLE 1 Castor Wax MP 70 Flakes PARAMETERS SPECIFICATION TEST METHOD Acid Value 2.5 maximum AOCS Da 14-48 Saponification Value 176-186 AOCS Cd 3-25 Hydroxyl Value 154-175 AOCS Cd 13-60 Melting Point, ° C. 68-72 AOCS Cc 3-25 Iodine Value 40-50 AOCS Tg 1a-64

(8) The hydrogenated castor wax MP 70 flakes can be procured from Acme Hardesty Oleochemicals of Bluebell, Pa. The designation MP 70 pertains to the melting point, 70° C. Other versions, including MP 60 and MP 80, are available with melting points of 60° C. and 80° C. respectively.

(9) Grade 3626 of expandable flake graphite is useful in preparing the formulation (1) above. The properties of the expandable flake graphite is set forth in Tables 2, 3, and 4 below.

(10) TABLE-US-00002 TABLE 2 General Product Description Expandable Flake Characteristic Minimum Maximum % Moisture 0 1 % Sulfur 0 4 % ExpCarb 80 100 % +20 Total (850 Micron) 0 0.1 % +80 Total (180 Micron) 0 30 % −200 Total (75 Micron) 0 25 Expansion Ratio X:1 130 180 pH 5 10

(11) TABLE-US-00003 TABLE 3 Typical Analysis (U.S. Standard Test Sieves) % Moisture 0.69 % Sulfur 3.08 % ExpCarb 91.03 % +20 Total (850 Micron) 0 % +40 Mesh (425 Micron) 0.01 % +60 Mesh (250 Micron) 0.4 % +70 Mesh (212 Micron) 2.45 % +80 Mesh (180 Micron) 17.89 % +80 Total (180 Micron) 20.61 % +100 Mesh (150 Micron) 30.57 % +200 Mesh (75 Micron) 40.3 % −200 Total (75 Micron) 8.52 % +325 Mesh (44 Micron) 5.8 % −325 Mesh (44 Micron) 2 .72 Expansion Ratio X:1 150 pH 6.52

(12) TABLE-US-00004 TABLE 4 Test Methods % Expanded Carbon E4-6 % Moisture E4-2 % Sulfur E4-9 Expansion Ratio E4-4 pH E4-5B Sieve Analysis E-2

(13) The grade 3626 expandable flake graphite can be procured from Asbury Graphite of North Carolina Inc., 191 Magna Blvd., Lumberton, N.C. 28360.

(14) Other grades of expandable flake graphite, shown in Table 5 below are also suitable for the formulation (1) above.

(15) TABLE-US-00005 TABLE 5 Expandable Flake Graphite Grades Nominal Carbon Moisture Sulfur Expansion pH Grade Size μm (%) (%) (%) Ratio (cc/g) Range 3772 >300 ≥98 0.9 3.1 300:1 5-10 1721 >300 ≥98 0.9 3.5 300:1 1-6  3721 >300 ≥95 0.9 3.5 290:1 5-10 1722 >300 ≥95 0.9 3.5 290:1 1-6  3335 >300 ≥85 0.9 3.2 270:1 5-10 3577 >300 ≥85 0.9 3.4 270:1 1-6  3570 >180 ≥80 0.8 3.1 230:1 5-10 1395 >180 ≥80 0.8 3.5 230:1 1-6  3558 >180 ≥99 0.8 3.1 210:1 5-10 3626 >75 ≥80 0.6 3.0 160:1 5-10 3494 >75 ≥80 0.9 2.9  90:1 1-6  3538 <75 ≥80 1.4 2.6  60:1 5-10

(16) The specification for the copper powder of formula (1) is shown in Table 6 below.

(17) TABLE-US-00006 TABLE 6 BR-83 UP Copper Color shade: Copper Pigment type: Cornflake pigment Leafing/non-leafing: Non-leafing NVM: 100 Shelf life: 12 months Fatty Acids: 1.1% max Typical particle size D10 in Helos [μm]: 4 D50 in Helos [μm]: 8 D90 in Helos [μm]: 17

(18) The copper powder can be procured from Eckart America Corporation, 4101 Camp Ground Road, Louisville Ky. 4021.

(19) The above formulation (1) may also include other solid lubricants instead of copper including sulphides, selenides, and tellurides (chalcogenides) of molybdenum, tungsten, niobium, tantalum, titanium (eg. WS.sub.2, WS.sub.2, MoSe.sub.2, TaSe.sub.2, TiTe.sub.2), monochalcenides (GaS, GaSe, SnSe), chlorides of cadmium, cobalt, lead, cerium, zirconium (eg. CdCl.sub.2, CoCl.sub.2, PbCl.sub.2, CeF.sub.3, PbI.sub.2), borates (eg. Na.sub.2B.sub.4O.sub.7), sulfates (Ag.sub.2SO.sub.4), or oxides (B.sub.2O.sub.3, MoO.sub.2, ZnO, Re.sub.2O.sub.7, TiO.sub.2, CuO—MoO.sub.2, NiO—Mo.sub.2, PbO—B.sub.2O.sub.3, CuO—Re.sub.2O.sub.7).

(20) When tested, the formulation (1) above achieved an auto-ignition temperature above 1000° F. (538° C.) and approached 1200° F. (538° C.). Because the formulation (1) comprises individual ingredients, each with proven lubrication properties, the combination of formula (1) provides a synergistic solid lubrication bar that is eco-friendly and avoids the use of toxic flame retardant compounds. Consequently, the formulation (1) provides superior lubrication performance when used with high temperature kilns.

(21) In some cases, a blend of zinc borate Zn[B.sub.3O.sub.4(OH).sub.3], magnesium hydroxide (MDH), and alumina trihydrate (ATH) can assist in providing additional flame retardancy and fire suppression because of the different temperatures at which zinc borate, ATH, and MDH decompose to generate water molecules. The following formula (2) by weight is useful in implementing the solid lubrication bar of the present invention.

(22) Hydrogenated castor oil or wax 50%

(23) Expandable flake graphite 40%

(24) Copper powder 5%

(25) ATH 1%

(26) MDH 2%

(27) Zinc borate 2%

(28) In the above formula (2), the hydrogenated castor oil or wax can range from 40%-60% by weight, the expandable flake graphite can range from 30%-50% by weight, the copper can range from 3%-6% by weight, the ATH can range from 2%-5% by weight, and MDH can range from 2%-3% by weight and zinc borate can range from 2%-3% by weight. Formula (2) above has an auto-ignition temperature above 1000° F. and provides superior lubrication performance when used with high temperature kilns.

(29) A formula (3) below is also useful in implementing the solid lubrication bar of the present invention.

(30) Hydrogenated Castor oil or wax 50%

(31) Expandable flake graphite 40%

(32) Copper Powder 5%

(33) ATH 1%

(34) MDH 1%

(35) Zinc borate 3%

(36) In the above formula (3), the hydrogenated castor oil or wax can range from 40%-60% by weight, the expandable flake graphite can range from 30%-50% by weight, the copper can range from 3%-6% by weight, the zinc borate can range from 1%-3%, by weight, and MDH can range from 1%-2% by weight and ATH can range from 1%-2% by weight. Formula (3) above has an auto-ignition temperature above 1000° F. and provides superior lubrication performance when used with high temperature kilns.

(37) While this invention has been described with reference to preferred embodiments thereof, it is to be understood that variations and modifications can be affected within the spirit and scope of the invention as described herein and as described in the appended claims.