US3684726A

US3684726A - Lubricating grease

Info

Publication number: US3684726A
Application number: US831223A
Authority: US
Inventors: Alfred Romuald Haak; Wolfgang Stichnoth
Original assignee: Individual
Current assignee: Individual
Priority date: 1968-06-22
Filing date: 1969-06-06
Publication date: 1972-08-15
Anticipated expiration: 1989-08-15
Also published as: NL6909290A; FR2011476A1; DE1769651B1; JPS4931001B1; FR2011476B1; BR6909997D0; GB1230949A

Abstract

LUBRICATING GREASES COMPRISED OF A METAL SOAP AND A MAJOR AMOUNT OF MINERAL OIL ARE IMPROVED IN THEIR ANTICORROSION PROPERTIES BY INCLUDING IN THEM SYNERGISTIC MIXTURES OF A BARIUM ALKARYL SULFONATE WHEREIN THE ALKARYL GROUP HAS A MOLECULAR WEIGHT BETWEEN 330 AND 430 AND A NAPHTHENATE SALT OF ZINC, LEAD, LITHIUM OR MAGNESIUM.

Description

United States Patent "ice Meme, 2512 31 2 The naphthenate may be a salt formed from metals of 3,684,726 Groups I to IV of the Mendeleev Periodic table. LUBRICATING GREASE A preferred form of grease in accordance with the Alfred Romlla d Haak, 2105 Meckelfeld, Mohhweg invention may comprise about 1.5 percent by weight of the Germany, and Wolfgang stlchnoth 15 Muhlensfl'asse naphthenate salt and about 0.5 percent by weight of the 2000 Hamburg 70, Germany sulphonate salt.

P 17 69 551 sulphonate, and the metal soap matrix of the grease may I t, (3], 010m 5/22, 5/16 be a salt of 12-hydoxystearic acid, such as the lithium salt US. Cl. 25233.2 5 Claims thereof.

In order to demonstrate the technical advance provided by the invention, a number of tests were performed in ABSTRACT OF THE DISCLOSURE accordance with the method of DIN 51802 in which rela- Lubricating greases comprised of a metal soap and a rotahoh is Produced between a a g face a d a major amount of mineral oil are improved in their antil5 Shaft which are Separated by Toner g the beaflngs corrosion properties by including in them synergistic rniX- helhg lubncatad y the grease under test In the Presence tures of a barium alkaryl sulfonate wherein thealkaryl of stahdardlzad q y 0f Wataf- A ter a standard group has a molecular Weight between 3 and 430 and a per1od of operation, the amount of COIIOSIOD is determined.

naphthenate salt of zinc, lead, lithium or magnesium. Each test was Performed w fi me with distilled water and the second time using a synthetic seawater formulated in accordance with procedure B of test ASTM D 665.

The amount of corrosion was expressed on an arbitrary scale in which zero corresponds to no corrosion of the surface of the test sample,and 5 designates over 10% of the The corrosion of metal parts lubricated by grease in hostile environments is mitigated by including 1n the grease a synergistic combination of naphthenates and sulphoft present invention relates to lubricating grease. A surface of the test sample corroded. Corrosion of less than lubricating grease basically comprises lubricating oil 10% of the Surface was P h a Pf raia asis. trapped i h interstices of a n-i f Soap fib Th The results of the tests are summarised 1n the following soap is usually a metal salt of a long chain organic acid table:

TABLE 7 Test number 1 2 3 4 5 6 7 8 9 10 11 12 13 4 15 Grease (90 wt. percent mineral oil plus 10% lithium 12 hydroxystearate 100 99.5 99.0 98 0 98.0 98.0 98.0 99.5 99.0 98.0 98.5 98.0 99.0 98.0 98.0 Lead naphthenatm. 2 0 "56 0,5 Lithmmmphthmt '"""11113111112:. .ra:::::. ::"i'a"'z 's':::::: "i' lirgnm 2.0 g 0 fiiiifii lh impmarnamnesia: 0.5 1.0 2.0 0.5 0.5 0.5 0.5 0,5

OHOSIOD es S1 3 2 1 0 o 0 e 0 o 0 0 o o 0 0 8% $333 32125 i'ii tifi a inmgtarains-6e- 5 4 a 2 2 2 1-2 4 3 3 2 O H 0 0 and among the commonly used soaps are the metal salts An examination of the data in the table shows that in of 12-1 d i id, tests 2 to 10, a s ngle additive, elthena naphthenate salt Lubricating grease often is employed in situations where or a sulphonate, lmproved the corroslon protection with moisture can penetrate to the metal parts which are lubrlr spect to the grease alone in t s both W1th dlstllled cated by the grease, for example, in steam-driven turbines. water and sea-water accordmg to test DIN 51802. Greases employed in such situations may contain additives However, 1t will be seen that when a combination of which combat any tendency of the metal parts to become one or more naphthenates w th the sulphonat 1 mcPrcorroded by the moisture. Commonly-used additives are porated 1n the grease, t e ls a synerglstlc effect which metal salts of naphthenic acid or alternatively metal salts confers further corrosion protection properties on the of sulphonic acids. However, these additives are not corng as C mpared W1th the amount of rotection when pletely effective in preventing corrosion, and are relatively only one additive chem1c al is employed. In the case of ineffective where the moisture is associated with inorganic tests 14 a d 15, there is complete corroslon protect on salts, as is the case with seawater. even in the Presence er- I I It has now been discovered, in accordance with the in- In further tests Whlch w Carried out, this time 1n vention, that improved anti-corrosion properties are imaccordance with ASTM D 1743, the basic gfeasa had a parted to a lubricating grease by incorporating in the COTTOSIOH pl'otectlofl 0f 011 he Scale prescnbed 1n grease an additive comprising a combination of at least ASTM D 1743- W 2 Welght Percent of bahlum ylone sulphonate salt and at least one naphthenate salt. naphthalene sulphonate was rp r ed 111 he baslc As will be seen from data given below, the combination grease, the protection as d termined by ASTM D 1743 a 1 2I of sulphonate and naphthenate salts act synerglstically to was provide corrosion protection of metal parts even in the hlehds ware made P 0f the bfislqgfeasa w h 2% y presence f Seawater. weight of the naphthenates of lead, mm and lithium, and

The sulphonate salt is preferably a salt of an alkaline tested according to ASTM D 1743- each blend, the

earth metal from Group 11(a) of the Mendeleev Periodic corrosion Pl'otection was It was found that no improvement could be obtained table (Such as banum calcium or Strontium) but Sulpho in the corrosion protection by increasing the concentration nates of metals in Groups 11(b) (such as magnesmm and of the additive in the just described tests- Zihc) y also be employed- However, when a grease blend comprising 1 wt. percent The sulphonates y he a Petroleum sulphonate an 7 of barium dinonylnaphthalene sulphonate and 0.5 wt. peralkafyl sulphonata- Preferably, the molecular weight of cent of zinc naphthenate was tested, the corrosion protecthe hydrocarbyl group of the sulphonate is 330 to 430. tion according to ASTM D 1743 was 1, thus demonstrating the synergistic effect of combining a naphthenate and a sulphonate.

These results serve to confirm the results summarized above in the table.

A grease giving highly satisfactory corrosion performance has been made which comprises about 1.5 weight percent of the naphthenate and about 0.5 weight percent of the sulphonate.

The additives in accordance with the invention do not detract from the lubricating properties of the grease.

We claim:

1. A grease composition comprising mineral lubricating oil thickened with lithium 12-hydroxystearate and containing synergistic corrosion inhibiting proportions of at least one naphthenate salt of a metal selected from the group consisting of lead, zinc, magnesium, and lithium and a barium salt of an alkaryl sulfonic acid wherein the alkaryl group has a molecular weight between 330 and 430.

2. A lubricating grease claimed in claim 1 wherein the naphthenate salt is zinc naphthenate.

3. A lubricating grease as claimed in claim 1 wherein the naphthenate salt is lead naphthenate.

References Cited UNITED STATES PATENTS 8/1953 Matthews et a1. 252-33.2 2/1970 Haak et a1. 25233 OTHER REFERENCES Polar-Type Rust Inhibitors by Baker et al. in Industrial and Engineering Chemistry, vol. 40, No. 12, pp. 2338-2347.

DANIEL E. WYMAN, Primary Examiner I. VAUGHN, Assistant Examiner US. Cl. X.R. 25237.7, 389