Solid anti-friction devices – materials therefor – lubricant or se – Lubricants or separants for moving solid surfaces and... – Organic sulfur compound – wherein the sulfur is single bonded...
Reexamination Certificate
2000-04-04
2001-05-01
Howard, Jacqueline V. (Department: 1764)
Solid anti-friction devices, materials therefor, lubricant or se
Lubricants or separants for moving solid surfaces and...
Organic sulfur compound, wherein the sulfur is single bonded...
C508S410000, C508S412000, C508S418000
Reexamination Certificate
active
06225267
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an emulsifier composition comprising at least one natural petroleum sulfonic acid salt produced by treating petroleum oil with oleum or sulfur trioxide, at least one branched chain alkylaryl sulfonic acid salt, at least one linear alkylaryl sulfonic acid salt, and at least one other optional sulfonic acid salt that may be used to adjust equivalent weight. This combination provides a system with good oil compatibility and optimum emulsion performance.
BACKGROUND OF THE INVENTION
Sodium petroleum sulfonates are widely used as the primary emulsifier in formulating emulsifiable lubricating compositions used for cutting fluid, hydraulic fluids, metalworking lubricants, and so forth.
Sodium petroleum sulfonates are typically produced as a by-product of refining processes in which certain highly refined petroleum products such as white lubricating oils, medicinal oils, and certain grades of transformer oils, are produced. The highly refined petroleum products are produced by treating a refined petroleum distillate or raffinate with fuming sulfuric acid which reacts with certain components of the oil to produce sulfonic acids, some of which are oil-soluble and some of which are water-soluble, thus forming a two-phase system. The two phases separate into two layers one of which is the oil layer containing the oil-soluble reddish-brown or mahogany sulfonic acids, and one of which is the water-soluble layer commonly referred to as an acid sludge layer that contains resinous materials, unreacted sulfuric acid, and water-soluble or green sulfonic acids. The layers are then separated and the oil-soluble sulfonic acids are recovered from the oil layer, usually in the form of their sodium salts.
The mahogany sulfonic acids being preferentially oil-soluble have found wide use in the preparation of emulsifiable petroleum products, such as in soluble cutting oils, hydraulic fluids, metalworking lubricating fluids for forming of metals, and so forth. The acid oil layer is neutralized to make a sodium salt and extracted with a polar solvent, typically alcohol, to separate most of the oil phase, and to increase the activity of the sodium sulfonate. This type of process is discussed generally in U.S. Pat. No. 1,930,488. The manufacture of white oils by the above process has become increasingly uneconomical and as a result, the production of sulfonates as by-products of white oil refining is substantially declining. This has left a significant shortage of sodium petroleum sulfonates.
Another major disadvantage with the natural petroleum sulfonates is their inconsistency in quality, and hence a variance in their emulsifying properties. In order to improve emulsification properties, secondary surface active agents of different types are often added, for instance, fatty acid salts. The amount of the secondary surface active agent used is varied depending on the quality of the sulfonate being employed. U.S. Pat. No. 4,140,642 describes an improved emulsifier composition in which salts of alkylaryl sulfonic acids are employed with an organic or mineral base, and in which the equivalent weights of the acids are distributed according to a function of C=f(M) where C denotes the concentration and M denotes the equivalent weight of individual acids, which function has two distinct equivalent weight maximum M
1
and M
2
, with M
1
<M
2
. Surprisingly, the present inventors have found a blend of sulfonates that provides an emulsifier composition that has consistent emulsification properties, and that is economical as well. This blend comprises at least one natural alkali metal petroleum sulfonate that is not prepared as a by-product of an oil refining process and may be non-extracted, and a blend of other high active synthetic sulfonates or sulfonic acids selected so as to produce an emulsification system that has 60% or greater active content, and selected so as to balance the oil solubility and emulsification performance thus providing an excellent surfactant system.
SUMMARY OF THE INVENTION
The emulsifier blend according to the invention comprise a blend of sulfonates or sulfonic acids that may be neutralized to the salt form, the blend comprising at least one natural sodium petroleum sulfonate that is derived from a typical lube base oil of 15-400 Cst viscosity at 40° C., and preferably is a non-extracted sodium petroleum sulfonate, at least one branched alkylaryl sulfonate, at least one linear alkylaryl sulfonate, and optionally, at least one other sulfonic acid or salt that preferably has an active content of 60% or greater. Any of these compounds may be supplied either in salt or in acid form. Optionally, other extracted petroleum sulfonates may also be added to the compositions of the present invention. The branched sulfonate is preferably an alkylbenzene and the linear sulfonate is preferably an alkylxylene.
The optional sulfonic acid or salt may be selected from a group of compounds including low, medium, high and very high equivalent weight sodium petroleum sulfonates; low, medium and high equivalent weight synthetic sodium sulfonates; low, medium and high equivalent weight sulfonic acids; high equivalent weight branched and linear alkylbenzene sulfonic acids where the side chain is C
8
to C
30
; and C
10
to C
4
sulfonated alkylation bottoms as sodium salts. The natural sulfonic acid salts of the present invention are prepared by oleum or SO
3
sulfonation of the aromatics contained in a typical lube base oil of 15-400 cSt viscosity at 40° C. The acid oil is desludged by gravity settling and neutralized with any monovalent cation from a base, preferably sodium. The sulfonate is not extracted or solvent treated to remove oil or salts. The process is thus simplified over previously used processes for preparing natural petroleum sulfonic acid salts for use in emulsifier compositions. The present invention further relates to a method of preparing an emulsifier composition suitable for mixing with oil to form lubricants comprising the steps of preparing a non-extracted natural petroleum sulfonate comprising the steps of providing a petroleum oil; adding fuming sulfuric acid or sulfonating agent to the petroleum oil; desludging the petroleum oil; and neutralizing the petroleum oil. This process is simplified and more economical than previous manufacturing procedures in that no extraction step is required. At least one branched chain alkylaryl sulfonic acid or salt thereof and at least one linear alkylaryl sulfonic acid or salt thereof is then added to the non-extracted natural petroleum sulfonate. Optionally, one or more sulfonic acids or salt thereof derived from alkylation bottoms may be added to the mix. All remaining sulfonic acid is then neutralized with one or more monovalent cation bases such as NaOH to form a neutral salt.
This sulfonate salt mixture may then be added to a mineral oil such as a naphthenic or paraffinic oil as a primary emulsifier to make cutting fluid concentrate for metalworking. Additional co-emulsifiers and lubricity additives may be usefully included as well. The cutting fluid concentrate is then added to aqueous media forming an emulsion that is useable as a metalworking lubricant. The term “cutting fluid” refers to the use of both emulsions and oils.
DETAILED DESCRIPTIONS OF THE PREFERRED EMBODIMENTS
The first component of the inventive composition are natural petroleum sulfonates or sulfonic acid salts prepared using sulfuric acid, oleum, (i.e. fuming sulfuric acid) and/or sulfur trioxide or other sulfonating agent to sulfonate petroleum oil, preferably a paraffinic oil. A preferred oil for use herein is a typical lube base oil of 15-4000 cSt @ 40° C. The acid oil is desludged by settling using natural gravitational forces, and is subsequently neutralized to about a 15-30%, preferably about 20-30% active petroleum sulfonate in oil. No further extraction or processing for the removal of oil or salts is conducted. These sulfonates will be hereinafter referred to as non-extracted sulfonates to distingui
Eckard Alan
Riff Igor
Weaver, Jr. Joseph A.
CK Witco Corporation
Howard Jacqueline V.
Reitenbach Daniel
LandOfFree
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