Additives made by reaction of (A) at least one phosphorus acid compound of the formula: ##STR1## wherein each X is independently oxygen or divalent sulfur, M is hydrogen or an equivalent of metal or ammonium cation, R is a hydrogen atom or a hydrocarbyl or hydrocarbyloxy or hydrocarbyl mercapto group of about one to about 30 carbon atoms and R' is XM or R with the proviso that the total number of carbon atoms in both R and R' is at least two, with (B) at least one sulfo-containing compound of the formula: ##STR2## or and ##STR3## wherein y is one or two, R3 is hydrogen or lower alkyl group, R2 is a divalent or trivalent hydrocarbyl group, R4 is a trivalent hydrocarbyl group, and Q is --OH, --OR3, --OM, an alkylene polyamine residue, or N(R3)2, are novel and useful and have utility as, for example, additives for water-containing hydraulic fluids.
|
9. A lubricating oil comprising a major amount of oil and a minor amount of at least one additive sufficient to impart improved load-carrying properties thereto wherein said additive is a sulfo-, nitrogen- and phosphorus-containing additive made by reacting
(A) at least one phosphorus acid compound of the formula: ##STR23##
wherein each X is independently oxygen or divalent sulfur, M is hydrogen or an equivalent of metal or ammonium cation, R is a hydrogen atom or a hydrocarbyl or hydrocarbyloxy or hydrocarbyl mercapto group of about one to about 30 carbon atoms and R' is XM or R with the proviso that the total number of carbon atoms in both R and R' is at least two, with (B) at least one sulfo-containing compound of the formula: ##STR24## wherein y is one or two, R3 is hydrogen or lower alkyl group, R2 is a divalent or trivalent hydrocarbyl group, R4 is a trivalent hydrocarbyl group, and Q is --OH, --OR3, --OM, an alkylene
polyamine residue, or N(R3)2. 1. A lubricating oil comprising a major amount of oil and a minor amount of at least one additive sufficient to impart improved load-carrying properties thereto wherein said additive is a sulfo-, nitrogen- and phosphorus-containing additive selected from those corresponding to the formulae: ##STR22## and mixtures of two or more such additives wherein z is one or two, each X is independently oxygen or divalent sulfur, R is hydrogen or a hydrocarbyl, hydrocarbyloxy, or hydrocarbyl mercapto group of about one to about 30 carbon atoms, and R' is XM or R, M being a hydrogen, an equivalent of a metal or ammonium cation, with the proviso that the total number of carbon atoms in both R and R' is at least two, y is one or two, each R3 is independently hydrogen or lower alkyl group of one to seven carbon atoms. R2 is di- or trivalent hydrocarbyl group having one to 18 carbon atoms, R4 is a trivalent hydrocarbyl group having one to 18 carbon atoms, and Q is selected from the group consisting of --OH, --OR3, --OM, --O(Alkylene--O)n --R3, --N(R3)2, --NR3 (Alkylene-NR3)n R3, --OH(R3)4, --ON(R3)4, and ---ONR3 -(Alkylene-NR3)n R3, wherein n has an average value of about one to about 10, M is as defined above and the alkylene group has from one to 10 carbon atoms.
2. The oil of
3. The oil of
5. The oil of
7. A concentrate comprising a substantially inert liquid diluent or solvent and at least one additive as claimed in
8. A concentrate comprising about 60 to about 5 parts of a substantially inert diluent or solvent and 40 to 95 parts of at least one additive as claimed in
10. An oil as claimed in
11. An oil as claimed in
12. An oil as claimed in
13. An oil as claimed in
14. An oil as claimed in
15. An oil as claimed in
16. An oil as claimed in
|
|||||||||||||||||||||||||||||||||||||||||||
This invention relates to new compositions of matter and to lubricating and functional fluids containing them. More particularly, the compositions of this invention are additives made by the reaction of certain phosphorus acid compounds with certain sulfo-containing compounds. This invention also relates to lubricant and hydraulic fluid compositions comprising these additives as well as processes for preparing the additives.
The use of sulfo-, nitrogen-, and phosphorus-containing compositions as additives for lubricants and functional fluids to improve one or more performance characteristics of such materials is well known. Among the functional fluids whose properties can be so improved are aqueous hydraulic fluids. Some hydraulic fluids are based on mixtures of glycol, water and oil, while others are based on oil-water emulsions. Regardless of their specific type, these aqueous hydraulic fluids are particularly useful in areas where fire resistance is of prime concern, such as on ships, in steel mills, etc. It is desirable to impart extreme pressure properties to such aqueous hydraulic fluids and it is an advantage of this invention that through its practice this can be done.
Further general background on the use of aqueous hydraulic fluids, their properties and compositions can be found in "Lubrication" Vol. 48, 161 (1962) published by Texaco Inc. of N.Y., N.Y., which is expressly incorporated herein for its background information and discussion of aqueous hydraulic fluids.
It is known that various types of phosphorus acids can be reacted with unsaturated carboxylic acid derivatives such as acrylamides and nitrato compounds (see for example, U.S. Pat. Nos. 2,709,156, 2,742,431, 2,766,208, and 3,098,824). It has not been previously known or suggested, however, that phosphorus acid compounds can be reacted with sulfo-, nitrogen-containing olefinic compounds to produce the additive compositions of this invention or to incorporate those additive compositions in lubricant and functional fluid compositions such as those of the present invention.
A novel class of phosphorus-, sulfo-, and nitrogen-containing products which are useful as additives for lubricants and functional fluids, particularly aqueous hydraulic fluids, has been found. These additives are made by reacting certain phosphorus acid compounds with sulfo- and nitrogen-containing olefinic substrates. Aqueous hydraulic fluid compositions prepared by combining these additives with glycol-water and oil-water emulsion fluids are within the scope of this invention.
The phosphorus acid compounds, (A), used as addends in making the additives of the present invention are of the formula: ##STR4## wherein each X is independently oxygen or divalent sulfur, M is hydrogen or an equivalent of a metal or ammonium cation, R is hydrogen or a hydrocarbyl, hydrocarbyloxy or hydrocarbyl mercapto group of about one to about 30 carbon atoms and R' is XM or R, with the proviso that the total number of carbon atoms in both R and R' is at least two. Preferably each X is oxygen and each R and R' contains between one and 18 carbon atoms and is substantially aliphatic in nature; more preferably both R and R' are independently C1-18 alkoxy groups and each X is a divalent sulfur atom.
When reference in this specification and the appended claims is made to hydrocarbyl, hydrocarbyloxy, hydrocarbyl mercapto, aliphatic or alkyl groups, it is to be understood, unless expressly stated to the contrary, that reference is also being made to substantially hydrocarbyl, substantially hydrocarbyloxy, substantially hydrocarbyl mercapto, substantially aliphatic, and substantially alkyl groups. The description of these groups as being substantially hydrocarbyl means that they contain no non-hydrocarbyl substituents which would significantly affect the principal hydrocarbyl characteristics or properties of the group relevant to their uses as described herein. Thus, it is obvious, for example, in the context of this invention, that a purely hydrocarbyl C20 alkyl group and a C20 alkyl group substituted with a methyl mercapto or methoxyl substituent at a point in the chain remote from other polar (i.e., non-hydrocarbyl) groups, would be substantially similar in its properties with regard to its use in this invention, and would in fact be recognized as art equivalents by those of ordinary skill in the art. That is, one of ordinary skill in the art would recognize both such groups to be substantially hydrocarbyl, etc.
Non-limiting examples of substituents which do not significantly alter the hydrocarbyl, etc., properties or nature of hydrocarbyl, etc., groups of this invention are the following:
Ether groups (especially hydrocarbyloxy and particularly alkoxy groups of up to ten carbon atoms)
Amino groups (including mono- and disubstituted aminos such as mono- and dialkyl amino or mono- and diaryl amino and the like, e.g., ethyl amino, dimethyl amino, diheptyl amino, cyclohexyl amino, benzyl amino, etc.)
Oxo groups (e.g., ##STR5## such as in ketones and aldehydes) Oxa groups (e.g., --O-- linkages in the main carbon chain)
Nitro groups
Imino groups (e.g., ##STR6## linkages in the main carbon chain) Cyano groups
Fluoro groups
Chloro groups
Thioether groups (especially C1-10 alkyl thioether)
Thia groups (e.g. --S-- linkages in the main carbon chain)
Carbohydrocarbyloxy groups (e.g., ##STR7## hydrocarbyl) Sulfonyl groups
Sulfinyl groups
This list is intended to be merely illustrative and not exhaustive and the omission of a certain class of substituent is not meant to require its exclusion.
In general, if such substituents are present, it will be found that not more than two for each ten carbon atoms in the hydrocarbyl group and preferably not more than one for each 10 carbon atoms, will not substantially affect the hydrocarbyl nature of the group. Nevertheless, the hydrocarbyl, hydrocarbyloxy, hydrocarbyl mercapto, etc., groups usually will be free from non-hydrocarbon groups due to economic considerations.
In the above formula, R and R' can be saturated or unsaturated and include alkyl, cycloalkyl, aryl, arylalkyl, alkylaryl, cycloalkenyl, etc. Suitable specific groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, amyl, isoamyl, n-hexyl, 2-ethylhexyl, 4-methyl-2-pentyl, cyclohexyl, chlorocyclohexyl, methylcyclohexyl, heptyl, n-octyl, tertiary octyl, nonyl, lauryl, cetyl, phenyl, bromophenyl, 2,4-dichlorophenylethyl, chlorophenyl, nitrophenyl, methoxyphenyl, ethylphenyl, propylphenyl, butylphenyl, benzylphenylethyl, octenyl, cyclohexenyl, ethyl cyclopentyl, N,N'-dibutylamino propyl phenyl, 3-nitro octyl, phosphorodithioiate phosphorodithioate salts in which the metal may be magnesium, calcium, barium, strontium, zinc, cadmium, lead or nickel. Zinc phosphorodithioates are particularly preferred. Other types of extreme pressure agents which can find use in the lubricating oil compositions of this invention include chlorinated waxes, sulfurized or phosphosulfurized fatty acid esters, di- or trihydrocarbyl phosphites and phosphates, dihydrocarbon polysulfides and metal dithiocarbamtes, carbamates. These and other useful extreme pressure agents are described in more detail in the books both entitled "Lubricant additives" by Smith and Smalheer (Published by the Lezius-Hiles Co., of Cleveland, Ohio) and by M. W. Raney (Published by the Noyes Data Corporation of Park Ridge, New Jersey) pages 146-212, both of which are incorporated herein by reference for their disclosure of additional extreme pressure agents which can be used in conjunction with the additives of the present invention.
Still another type of additive which can be useful in the lubricating oil compositions of the present invention is rust-inhibiting agents. One or more rust-inhibiting agents can be used. The most effective rust-inhibiting agents in the water-oil emulsions of this invention are aliphatic amines, especially aliphatic primary amines having at least eight carbon atoms in the molecule. Preferably, such amines are tertiary alkyl primary amines and have at the most thirty carbon atoms in the molecules. Other conventional rust-inhibiting agents can also be used, either alone or in combination with the amines discussed above.
Other conventional types of rust-inhibiting agents are salts of aromatic acids, such as benzoic acid, etc., with the afore-described amines. Hydroxy alkyl amines, particularly those with long chains, (i.e., C8 -C30 aliphatic amines) containing one or two hydroxy alkyl substituents on the nitrogen atom are also useful as rust-inhibiting agents in the lubricating oil compositions of this invention. Nitric acid salts of long-chained aliphatic amines such as those disclosed above are similarly useful.
The concentration of rust-inhibiting agent in the lubricating oil compositions and particularly the oil-water emulsions of this invention depend to some extent upon the relative concentration of water in the emulsion. Ordinarily from about 0.1 part to 2 parts of rust-inhibiting agent per hundred parts of emulsion is sufficient.
The oil-water emulsions of this invention may also contain a conventional foam inhibitor such as a commercial dialkyl siloxane polymer or polymer of a methacrylate. Freezing point depressants (i.e., water-soluble polyhydric alcohols such as glycerol or other polar substances such as the methyl ether of diethylene glycol) are also useful. The concentration of these additives is usually less than five parts per hundred parts of the oil-water emulsion.
Bacteriocides can also be included in the emulsions of this invention. These are illustrated by the nitrobromo alkenes such as 3-nitro-1-propylbromide, nitrohydroxyalkanes, such as tri(hydroxymethyl)nitromethane, 2-nitro-2-ethyl-1,3-propanediol and 2-nitro-1-butanol and boric acid esters such as glycerol borate. The concentration of such bacteriocides usually range between about 0.001 to about 1 part per hundred parts of the oil-in-water emulsion.
Oxidation inhibitors can also be included in the lubricating oil compositions of this invention. Hindered phenols such as 2,4-di-t-butyl-6-methyl phenol, 4,4'-methylene-(2,6-di-t-pentyl phenol), and 2,6-di-t-octyl-4-secondary butyl phenol, are representative of useful oxidation inhibitors. The concentration of such oxidation inhibitors in the lubricating oil compositions of this invention is usually between about 0.01 to about 2 parts per hundred parts of emulsion.
The following examples are illustrative of concentrates and oil-in-water emulsion compositions of the present invention.
| ______________________________________ |
| Component Pts by Wt |
| ______________________________________ |
| Emulsifier* 9.0 |
| Soybean Lecithin 1.8 |
| Tertiary alkyl primary amine having a mol wt |
| of 191 in which the tertiary alkyl |
| radical is a mixture of radicals |
| having 11 to 14 carbon atoms |
| 0.6 |
| Product of Example 1 5.0 |
| SAE 40 mineral lubricating oil |
| 284.0 |
| Silicone anti-foam agent 0.0075 |
| Water |
| ______________________________________ |
| *Emulsifier made by reacting a polyisobutenyl succinic anhydride with |
| (isobutenyl group=Mn 1000) with polyoxyethylene sorbitan monooleate. |
| ______________________________________ |
| Component Pts by Wt |
| ______________________________________ |
| Emulsifier of Example 14 9.0 |
| Soybean lecithin 1.8 |
| Tertiary alkyl primary amine having a mole- |
| cular weight of 330 in which the |
| tertiary alkyl radical is a mixture |
| of radicals having 18 to 24 carbon |
| atoms 0.6 |
| Lead diamyl dithiocarbamate |
| 3.0 |
| Product of Example 3 3.0 |
| SAE 20 mineral lubricating oil |
| 282.0 |
| Silicone anti-foam agent 0.0045 |
| ______________________________________ |
| ______________________________________ |
| Component Pts by Wt |
| ______________________________________ |
| Emulsifier of Example 14 |
| 18.0 |
| Soybean lecithin 3.6 |
| Nitric acid salt of the tertiary alkyl |
| primary amine of Example 14 |
| 1.2 |
| Product of Example 2 18.0 |
| 4-methyl-2,6-di-t-butyl phenol |
| 3.0 |
| SAE 5 mineral lubricating oil |
| 534.0 |
| Silicone anti-foam agents |
| 0.015 |
| Water 400.0 |
| ______________________________________ |
| ______________________________________ |
| Component Pts by Wt |
| ______________________________________ |
| The emulsifier of Example 14 |
| 45.0 |
| The product of Example 2 18.7 |
| Soybean lecithin 9.0 |
| Tertiary alkyl primary amine of Example 14 |
| 3.0 |
| SAE 40 mineral lubricating oil |
| 24.3 |
| Silicone anti-foam agent 0.022 |
| ______________________________________ |
| ______________________________________ |
| Component Pts by Wt |
| ______________________________________ |
| The product of Example 17 |
| 6.0 |
| SAE 40 mineral lubricating oil |
| 94.0 |
| ______________________________________ |
As noted above, the lubricant compositions of this invention can also be based on water-glycol mixtures. Such compositions usually comprise water as a solvent and flame retarder, a water-soluble organic polymer thickener such as a polyoxyethylene polymer or an acrylated methacrylate ester polymer, a water-miscible freezing point depressant, and small amounts of such additives as the afore-described anti-rust agents, oxidation inhibitors, and so on, as well as the additive compositions of this invention. The water-miscible freezing point depressant is usually a common glycol or glycol ether having from about 2 to 14 carbon atoms such as ethylene glycol, diethylene glycol, triethylene glycol, ethylene glycol ethers, such as ethyl, methyl propyl and butyl ethers thereof and similar ethers of diethylene glycol and triethylene glycol. In general, it is preferred to use simpler compounds such as represented by ethylene glycol, propylene glycol, butylene glycol, and diethylene glycol for they are cheap, easily obtainable and blend readily with water to give very low freezing point mixtures which form the good basis for hydraulic fluid compositions.
Usually, the water content of such water-glycol mixtures is limited to a maximum of about 45 percent to be free from freezing problems. The minimum amount of water is usually 10 percent also to avoid excessively high freezing points of the composition.
The preferred thickeners for use in these compositions are soluble organic polymeric compounds usually copolymers of ethylene oxide and 1,2-propylene or 1,3-propylene oxide. A preferred one is one containing about 75 mole percent ethylene oxide and about 25 mole percent of propylene oxide, copolymerized to a thick fluid polymer having a number average molecular weight of about and not in excess of 15,000 to 20,000. Such polymers have viscosities of about 50,000 to about 100,000 SUS at 100° F. Blends of such polymers may be used to achieve specific purposes. All of the fore-described additives which are used in the water-oil based hydraulic fluids can be used in appropriate circumstances in the water-glycol fluids. Usually solubility and compatibility dictate the choice of such additives which is within the skill of those skilled in the art.
The water-glycol based compositions of this invention contain 0.5 to 20 parts of the additives of the invention per hundred parts of the total mixture in addition to the glycol-water thickener and other noted additives.
Exemplary of the water-glycol based compositions of this invention are the following:
A mixture of equal weights of water and ethylene glycol is prepared containing as a thickener a copolymer of ethylene oxide and 1,2-propylene oxide of number average molecular weight 15,000 having a viscosity of 50,000 SUS at 100° F., and 3 parts per hundred parts of water-glycol base of the product of Example 1.
A mixture of 33 parts by weight water and 67 parts by weight ethylene glycol is prepared and treated with one part by weight per hundred parts of the copolymer of Example 19 and five parts by weight of the product of Example 3.
While the additives of this invention find particular use in the afore-described water-oil and waterglycol hydraulic fluids, they may also be used in lubricating compositions containing only natural or synthetic oils. Such usage is particularly favored when the additive composition is relatively non-polar, that is, it is an ester rather than a salt of free acid.
The additives of this invention can be effectively employed in a variety of lubricating compositions based on diverse oils of lubricating viscosity such as a natural or synthetic lubricating oil, or suitable mixtures thereof. The lubricating compositions contemplated include principally crankcase lubricating oils for spark-ignited and compression-ignited internal combustion engines including automobile and truck engines, two-cycle engine lubricants engines, aviation piston engines, marine and railroad diesel engines, and the like. However, automatic transmission fluids, transaxle lubricants, gear lubricants, metal-working lubricants, hydraulic fluids, and other lubricating oil and grease compositions can benefit from the incorporation of the present additives.
Natural oils include animal oils and vegetable oils (e.g., castor oil, lard oil) as well as solventrefined or acid-refined mineral lubricating oils of the paraffinic, naphthenic or mixed paraffinic-naphthenic types. Oils of lubricating viscosity derived from coal or shale are also useful base oils. Synthetic lubricating oils include hydrocarbon oils and halo-substituted hydrocarbon oils such as polymerized and interpolymerized olefins (e.g., polybutylenes, polypropylene, propylene isobutylene copolymers, chlorinated polybutylenes, etc.); alkyl benzenes (e.g., dodecylbenzenes, tetradecylbenzenes, dinonylbenzenes, di-(2-ethylhexyl)benzenes, etc.); polyphenyls (e.g., biphenyls, terphenyls, etc.); and the like. Alkylene oxide polymers and interpolymers and derivatives thereof where the terminal hydroxyl groups have been modified by esterification, etherification, etc., constitute another class of known synthetic lubricating oils. These are exemplified by the oils prepared through polymerization of ethylene oxide or propylene oxide, the alkyl and aryl ethers of these polyoxyalkylene polymers (e.g., methyl polyisopropyleneglycol ether having an average molecular weight of 1000, diphenyl ether of polyetehylene glycol having a molecular weight of 500-1000, diethyl ether of polypropylene glycol having a molecular weight of 1,000-1,500, etc.) or mono- and polycarboxylic esters thereof, for example, the acetic acid esters, mixed C3 -C8 fatty acid esters, or the C13 Oxo acid diester of tetraethylene glycol. Another suitable class of synthetic lubricating oils comprises the esters of dicarboxylic acid (e.g., phthalic acid, succinic acid, maleic acid, azelaic acid, suberic acid, sebacic acid, fumaric acid, adipic acid, linoleic acid dimer, etc.) with a variety of alcohols, (e.g., butyl alcohol, hexyl alcohol, dodecyl alcohol, 2-ethylhexyl alcohol, pentaerythritol, etc.). Specific examples of these esters include dibutyl adipate, di(2-ethylhexyl)sebacate, di-n-hexyl fumarate, dioctyl sebacate, diisooctyl azelate, diisodecyl azelate, dioctyl phthalate, didecyl phthalate, dieicosyl sebacate, the 2-ethylhexyl diester of linoleic acid dimer, the complex ester formed by reacting one mole of sebacic acid with two moles of tetraethylene glycol and two moles of 2-ethylhexanoic acid, and the like. Silicon-based oils such as the polyalkyl-, polyaryl-, polyalkoxy-, or polyaryloxy-siloxane oils and silicate oils comprise another useful class of synthetic lubricants (e.g., tetraethyl silicate, tetraisopropyl silicate, tetra-(2-ethylhexyl)silicate, tetra(4-methyl-2-tetraethyl)silicate, tetra(p-tert-butylphenyl) silicate, hexyl-(4-methyl-2-pentoxy)disiloxane, poly(methyl) siloxanes, poly(methylphenyl)siloxanes, etc.). Other synthetic lubricating oils include liquid esters of phosphorus-containing acids (e.g., tricresyl phosphate, trioctyl phosphate, diethyl ester of decane phosphonic acid, etc.), polymeric tetrahydrofurans, and the like.
The lubricating oil compositions of this invention comprise a major amount of oil and a minor, load-carrying improving amount of at least one additive composition of the invention. Generally, this amount will be about 0.5 to about 20 parts additive per hundred parts oil.
Exemplary of these lubricating oil compositions are the following:
A mixture of 95 parts of SAE 40 oil and 5 parts of the additive composition of Example 10.
A mixture of 90 parts of SAE 10 w/30 oil, 7 parts of the additive composition of Example 3 and 3 parts of 2,4-di-t-butyl-6-methyl phenol in an antioxidant.
As indicated above during the description of the oil-water emulsions of this invention, it is often convenient to form concentrates of the additives of this invention prior to incorporation of the additives in an emulsion composition. Such concentrates comprise about 40 to about 95 parts additive and about 60 to about 5 parts of substantially inert organic liquid diluents or solvents and are equally useful in preparing the lubricating oil composition of this invention. Analogous glycol-based concentrates comprising about 50 to about 95 parts additive composition and about 50 to about 5 parts of at least one glycol or glycol-ether are equally useful. Remarks made hereinbefore in regard to concentrates are applicable here.
| Patent | Priority | Assignee | Title |
| 4493780, | Mar 30 1981 | BASF Corporation | Water-based hydraulic fluids having improved lubricity and corrosion inhibiting properties |
| 4804489, | Oct 29 1987 | The Lubrizol Corporation; LUBRIZOL CORPORATION, THE, 29400 LAKELAND BOULEVARD, WICKLIFFE, OHIO 44092 A CORP OF OHIO | Low molecular weight viscosity modifying compositions |
| 5025085, | Nov 06 1989 | LUBRIZOL CORPORATION, THE, A CORP OF OHIO | Curable aminoplast compositions and catalysts for curing same |
| 5115083, | Nov 06 1989 | The Lubrizol Corporation | Curable aminoplast compositions and catalysts for curing same |
| Patent | Priority | Assignee | Title |
| 2566129, | |||
| 2709156, | |||
| 2742430, | |||
| 2742431, | |||
| 2766208, | |||
| 2806846, | |||
| 3094547, | |||
| 3098824, | |||
| 3873456, | |||
| 3926821, | |||
| 3954798, | Aug 19 1974 | Continental Oil Company | Process for preparing phosphorotriamidothioates |
| 4000188, | Dec 19 1975 | Ciba-Geigy Corporation | Alkylthioamido sulfonic acids and derivatives thereof |
| 4014926, | Dec 19 1975 | Ciba-Geigy Corporation | Fluorinated sulfonic acids and derivatives thereof |
| 4026812, | Dec 12 1973 | The Lubrizol Corporation | Phosphorus, nitrogen and sulfo-containing additives |
| Executed on | Assignor | Assignee | Conveyance | Frame | Reel | Doc |
| Dec 14 1977 | The Lubrizol Corporation | (assignment on the face of the patent) | / |
| Date | Maintenance Fee Events |
| Date | Maintenance Schedule |
| Nov 06 1982 | 4 years fee payment window open |
| May 06 1983 | 6 months grace period start (w surcharge) |
| Nov 06 1983 | patent expiry (for year 4) |
| Nov 06 1985 | 2 years to revive unintentionally abandoned end. (for year 4) |
| Nov 06 1986 | 8 years fee payment window open |
| May 06 1987 | 6 months grace period start (w surcharge) |
| Nov 06 1987 | patent expiry (for year 8) |
| Nov 06 1989 | 2 years to revive unintentionally abandoned end. (for year 8) |
| Nov 06 1990 | 12 years fee payment window open |
| May 06 1991 | 6 months grace period start (w surcharge) |
| Nov 06 1991 | patent expiry (for year 12) |
| Nov 06 1993 | 2 years to revive unintentionally abandoned end. (for year 12) |