US2383916A - Lubricants - Google Patents

Description

Patented Aug. 28, 1945 wail-f UNITED PATENT o rricizl LUBRIOANTs Johan. Morgan, South Oran e, N'. 3., a'ss'ign'oi' tof' v V Cities Service Oil'Company, Newt "York,

corporation of Pennsylvania 1 I Np Drawing. Application July 9, "19 42,

Serial No. 450.287, v I

This invention relates to lubricants which are 4 more particularly adapted for low temperature lubrication.

Many machines, such as the aeroplane, truck and automobile, operate in atmospheres which 5 may range in temperature from 50 F. to 200 F. A lubricant which is effective for lubrication in this temperature range should have a comparatively uniform viscosity throughout this temperature range.

The primary object of the present invention is to provide a lubricant and method of lubrication which are effective in a temperature range of -50 F. to 200 F.

Another object of the invention is to provide a lubricant which is stable and non-corrosive and which is capable of withstanding high bearing Pressures.

With these and other objects in View the invention consists in the lubricant and method of lubricating hereinafter described and particularly defined in the claims.

I have discovered that the alkyl lactates have physical characteristics whichladapt them for lubrication in a range of from 50 F.- to 200 F. The lactates which are more particularly adapted as lubricants are the alkyl lactates which are esters of a-hydroxypropionic acid or lactic acid.

The alkyl lactates, particularly adapted for lubricants, have the following physical properties:

Boiling Flash Melting point point point F. F. F. Ethyl lactate 311 129 But-y! lactate 370 160 Isohutyl l \ctute 350-390 l .5

These alkyl lactates are oily liquids and have the 40 following viscosities:

be seen that allofthese lactates have apparently uniform viscositythroughout the range of 40 F. to 200 F.

All of the alkyl lactates above mentioned have good lubricating values, that is they have better lubricating values than the regular petroleum lubricating spindle oil having a viscosity of 200 at F. If 3.2%, for example, of ethyl lactate is added to the spindle oil, the load-carrying capacity of the oil will be increased 20%.

By adding one of the well known extreme pressure addition agents to any of these alkyl lactates the load-carrying capacity of the lactate will be raised to a point where it will carry very high bearing pressures. For example with an extreme pressure 4-ball testing machine ethyl lactate would seize at 450 lbs. pressure. By the addition of 1% of Polane, the ester would not seize at 1000 lbs. pressure. It has been found that if 1% of Polane or tricresyl phosphite, or Santolube #261 is added to any of the alkyl lactates the load-carrying capacity would be raised to the point where they would not seize in the 4-ball testing machine at a pressure of 1000 lbs.

The ethyl and butyl lactates are well adapted for the manufacture of greases. These lactates with approximately 6% of sodium soap will form a grease that is stable and will not bleed. Preferably the lactate contains 1% of the extreme pressure additive to make the grease an extreme.

pressure carrying grease. The soap preferably is sodium stearate, although it has been found that; sodium oleate or sodium palmitate, or any of the sodium soaps of the fatty acids are adapted for making greases with the ethyl and butyl lactates. Such a grease may consist of approximately 93% of one of these lactates, approximately 6% of sodium stearate, and approximately 1% of an extreme pressure agent.

These lactates are neutral and non-corrosive in the metal bearings in which they have been employed and will elfectively adhere to the bearings through the temperature range of 40 F. to 200 F.

Most of the commonly used extreme pressure addition agents are soluble in the lactates and impart load-carrying capacities to the lactates. Polane is a product sold by the Patent Chemicals Company and is understood to be an ester of a fatty acid or a chlorinated ester of a fatty acid, such as ethyl laurate or chlormethyl stearate. Santolube #261 is manufactured by Monsanto Chemical Company and defined as a metallic derivative of an alkyiated carboxylic acid containing compounds of tin and sulIur. The ma cresyl'phosphite referred to above is described in the patent to Engelke- No. 2,260,303 granted October 28, 1941, and is described as a tricresyl phosphite, or a mixture of tricresyl phosphite and tricresyl phosphate. lhe above addition agents also; act as oiliness and anticorrosion aae Certain subject-matter disclosed herein is claimed in divisional application Serial N0. 519,649, filed January 25, 1944.

The preferred form of the invention been thus described, 'what is claimed as new is:

l. A lubricant consisting essentially of ethyl lactate having approximately 1% of an extreme pressure addition agent dissolved therein.

2. A lubricant comprising ethyl lactate 93%, sodium stearate 6%, tricresyl phos'phite 1%.

3. A lubricant comprising ethyl lactate 93 percent, sodium stearate 6 percent, and an extreme pressure addition agent 1 percent.

4. A lubricant consisting essentially of a liquid allryl lactate having an extreme pressure agent dissolved therein in sufficient proportion to impart extreme pressure properties to the lubricant.

8. A lubricant consisting of approximately 6% oi? sodium stearate, the remainder of the lubricant consisting essentially of ethyl lactate.

\ JOHN D. MORGAN.