Synthetic casein fiber elastic grease
US 2734862 A
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United States Patent SYNTHETIC CASEIN FIBER ELASTIC GREASE Amold.J.'Morway,,Rahway, NNL, .and RoherttP. Spray,
Pittsburgh, ;l.a., assignors to Esso Research and Engineering Company, a. corporation of. Delaware No Drawing. Application December 3, 1952, Serial No..323,928=
Claims. (Cl. 252-14) The present invention relates to improvements in elastic fiber greases and particularly to improvements in the elasticity of the fibrous component thereof.
Fiber greases are widely used for packing certain types ofjournal bearings, for example, inrailroad rolling stock.
A relatively large quantity of .such greases isconsumed by industry. Such greases usually'consist primarily of fibrous material such as wool=fiber or yarn impregnated or saturated with an oil or grease composition. This lubricant is packed. in a housing in such a way that it presses against the journal as it revolves and keeps. it
coated with a film of lubricant. The fiber or yarn acts .as areservoir for the oil or grease and prevents rapid consumption of .the lubricant while assuring continuous lubrication.
.ln .thegprior. artwhenthe. fibrous material, usually a reclaimed wool or yarn, has been used aloneincombination with the lubricant it has tended to become mattedrand soggy'and eventually to pull away from the bearing. This is particularly true when the bearings become heated up to temperatures of the order of 200 F.
"The oil rapidly evaporatesand the fibers lose their resistcoarser fiber such as horse hair, goat hair or other animal hair. The coarser and stiffer hair and thefinerwool fibers are stranded and interspersed with each other and the entire fibrous mass is thereafter saturated with the oil or grease. While horse hair, in particular, has some utility in this connection at ordinary temperatures it is not particularly satisfactory as temperatures go above 150 F. or so and it is not always available. Horse hair and other animal hair fibers are also susceptible to actual damage at elevated temperatures and start to decompose and become brittle at temperatures as low as 150 to 180 F. They are therefore quite unsuitable at the moderately high journal and bearing temperatures frequently encountered in service, e. g., up to about 200 F. or sometimes a little higher.
According to the present invention it has been discovered that a relatively new type of synthetic fiber consisting of an extruded casein monofilament is a particularly suitable material for incorporation in elastic fiber greases which have a tendency to mat and lose contact with the bearing. This new synthetic fiber of coarse type has considerably greater elasticity than horse hair or the other coarse animal hairs and in particular it retains its elasticity much longer at moderately elevated temperatures. It is also more economical than horse hair, and related materials, and is readily available in increasing quantities. Furthermore, this material can be produced in any diameter and length desired and may readily be made either straight or curled.
}Eor.p urposes of. the present invention the .curled extruded casein fiber of monofilament vtype is. particularlysuitable. .Filamentswhich have been tested for purposes of...the presentinvention have. the following characteristics:
Tenacity 0.5-1.0.g./denier. Tensile strength 8,500-l6,000 p. s. i. Impactstrength 50-100 ft.lbs./sq. in. Knot strength 5,000 7,'500/sq. im Diameter range; .0.005..0.l6", 145-1330 denier. Elongation at break. 2025%. Specific-gravity 1.29. Moisture-Regain:
65%" RH: 70F 10-15.%. 20% RH 70 F 6.5%. Burning rate Very slow. Resistance: to heat Some damage. starts at 210 F. Resistance to abrasion Good. Elastic recovery; Excellent. Solubility inorganic solvents.-- Insoluble. Color range Unlimitedtnat. color white).
Resistance to mold, mildew and Resistant.
,It will be seen from the foregoing that the curled casein monofilarnent of the type described .above isparticularly suitableforuse in typical iournal'bearings where there is. freqnentlysome temperature elevation. A par- Iticular' filament which ,is.quite satisfactory is one which is sold under the; trade name Caslan This Casla'n fiber i's-becorningincreasingly available and can readily .flbe stranded with reclaimed wool, wool yarn or other available types of fiber.
Itis preferred to combine the wool fiber and the .casein. fiber in proportions of about wool (such as shredded carpet waste, for example) with about 25'% by .to have asubstantial. portion of the finer wool'fiber presentlfor better. wicking or capillary feed of the lubricant.
The lubricatingingredient itself'is. preferably a lubrieating grease of soft consistency although an oil' without a special thickener can be used in many applications. The composition presently preferred includes 75 to 95% by weight of calcium soap-mineral oil lubricating grease. Such a grease may contain from 3 to 20% of calcium soap of higher fatty acids such as the C12 to C22 saturated and unsaturated fatty acids. The soap may be prepared, of course, from substituted acids such as' keto and hydroxy acids, for example, 4-keto-stearic acid or l2-hydroxy stearic acid, instead of fatty acids or in admixture therewith, if desired. Mixtures of soaps may be used andthe soaps of other metals such as sodium, potassium, lithium, or aluminum may be employed. The calcium soap greases are usually less expensive and have a desirable consistency at usual journal beating temperatures and they are normally preferred. Complex soaps of the soap-salt type may be used when high temperature grease stability is important.
Several examples were prepared in order to test out the invention. The first consisted of by weight of a standard lime soap grease having a soap content of about 10 to 12% by weight. This is a soft, smooth, nonfibrous grease composition. To this was added 15% by weight, based on the total composition, of a mixture of wool waste obtained from shredded carpet and ordinary horse hair, the mixture containing about 25% horse hair and 75% wool.
A second sample was prepared exactly as in the first except 1 that a. monofilament casein fiber (curled Caslan was employed in lieu'of the horse hair.
. A third sample was prepared as in the case of Sample 2except that the Caslan fiber was reduced to 90% 'ot the fiber being wool waste.
A fourth sample consisted of 85% of the same lime soap grease as in Sample 1 with of a blended fiber which contained 75% of long strand wool yarn and 25% Caslan fiber.
A fifth sample was the same as the fourth except that the Caslan fiber content was reduced to 10% of the total fibrous material.
It was observed in tests in journal bearings that 10% by weight of the Caslan was fully equivalent to 25 S. S.'U-. at 210 VP.) for 3 months at a temperature which ranged between 150 and 250 F. There was no appar ent deterioration of the Caslan fiber at the end of the test period. Also there did not appear to be any loss in elasticity over this extended period at the relatively high temperature range of 150 to 250 F. It will be appreciated that any fiber which tends to break down or become brittle at an operating temperature is quite unsatisfactory for industrial purposes. Even while being lubricated the journal bearings of railroad cars, for example, frequently become quite hot (200 F. or so) due to the heavy application of brakes to the wheels on long grades. The fibrous lubricating compositions of the present invention are substantially less susceptible to elastic deterioration at elevated temperatures than those of the prior art. They can be more closely controlled to obtain a desired degree of elasticity which may be maintained over a relatively long period of time. At the same time they are substantially less expensive than prior art compositions including horse hair. They are much more satisfactory in their resistance to packing or matting than standard fibrous lubricants which do not contain an elastic fiber.
It will be obvious that various types of oil, synthetic as well as mineral, may be used and that various thickeners may be used such as are used in the production of and the like maybe incorporated'as will be readily apparent to those skilled in the art.
What is claimed is:
1. An elastic fiber lubricant composition comprising a major proportion by weight of a lubricating grease and a minor proportion by weight of a fibrous mass comprising a major proportion of a mildly elastic wool fiber and about 10 to 40% by weight of a. highly elastic extruded monofilament curled casein fiber, which has strong resistance against matting at temperatures up to at least 200 F.
2. An elastic fiber lubricant composition comprising to by weight of calcium soap-mineral oil lubricating grease and a fibrous mass comprising a major proportion of a relatively fine fiber wool waste, which has a tendency to become matted, and a minor proportion of a relatively coarse highly resilient extruded monofilament curled casein fiber suflicient to overcome said matting tendency.
3. Composition according to claim 2 wherein the casein fiber comprises 10 to 25% of the fibrous mass and is substantially un about 210 F.
v 4. An elastic fiber lubricant composition consisting essentially of a fibrous mass impregnated with an oily lubricant, said mass comprising a major proportion of a W001 fiber, which has a tendency to become matted, and a minor proportion of a curled, relatively coarse elastic extruded monofilament casein fiber interspersed through said mass to overcome said matting tendency.
5. Composition according to claim 4 wherein the oily lubricant is a calcium soap thickened mineral base lubricating oil.
References Cited in the file of this patent UNITED STATES PATENTS 915,804 Stcarns Mar. 23, 1909 1,001,371 Drury Aug. 22, 1911 1,564,306 Fantz Dec. 8, 1925 2,342,994 Atwood Feb. 29, 1944 OTHER REFERENCES Klemgard: Lubricating Greases, Published 1937 by Reinhold Publishing Corp., 330 W. 42nd St., New York, N. Y., USA. Page 324.
Ser. No. 96,470, Ferretti (A. P. C.), published April 27, 1943.
ected by heat up to a temperature of.