Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – For cleaning a specific substrate or removing a specific...
Reexamination Certificate
1998-11-09
2002-08-06
Ogden, Necholus (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
For cleaning a specific substrate or removing a specific...
C510S185000, C510S488000, C510S492000, C134S040000
Reexamination Certificate
active
06429178
ABSTRACT:
This invention relates to compositions suitable, inter alia, as lubricant additives, and especially to calcium overbased detergents, and more especially to such materials suitable for use as additives to lubricants for use in marine engines.
To meet intense pressures on capital, maintenance, and running costs, marine engine manufacturers are producing new engines designed to minimize fuel and lubricant consumption, and are placing heavy demands on suppliers to provide lubricants that reduce wear and extend the period between overhauls. There is a continuing need for lubricant additives that provide detergency, antioxidant properties, and rust protection, and that neutralize corrosive acids from sulphur-containing fuels. Overbased detergents are uniquely able to fulfil all of these necessary roles.
Lubricant formulators are, as a result of the requirements placed on,them by engine manufacturers and users, in turn seeking higher total base number (TBN) overbased detergents, in order to reduce the treat rate while maintaining effectiveness. (In this specification, the TBN of an overbased detergent is the TBN, in mg KOH/g, as measured by ASTM D2896. ) There is also a need for products which, while being highly effective as additives, can be more cost-effective than existing products, and which are relatively easy to prepare and to handle.
Overbased metal-containing detergents suitable for use as lubricant additives are typically prepared as concentrates in oil. In such concentrates, a basic metal-containing material is maintained in dispersion or solution in the oil by a surfactant system comprising, for example, phenate, salicylate, sulphonate or naphthenate anions.
Overbased detergents initially contained a single type of anion, for example a member or members of the phenate group, or of the sulphonate group, but for many years compositions have been available that contain anions of two or more such groups, obtained either by adding two or more overbased detergents having different types of anion or by the manufacture of a hybrid material in which two or more anions of different groups are incorporated during the overbasing process. As basic materials, compounds of members of the alkali and alkaline earth groups are used, compounds of calcium being most frequently employed.
For a number of applications, for example, for lubricants for use in marine engines, it is frequently desirable, for maximum effectiveness, that overbased detergents contain a relatively high proportion of phenate and salicylate anions. Such overbased detergents may also be useful in other applications.
The present invention provides a calcium overbased detergent comprising a surfactant system derivable, and preferably derived, from at least two surfactants, at least one of the surfactants being a sulphurized or non-sulphurized phenol or a derivative thereof and the other, or at least one other, of the surfactants being a sulphurized or non-sulphurized salicylic acid or a derivative thereof, the total proportion, measured as described herein, of the said phenol and the said salicylic acid in the surfactant system being at least 55 mass %, and the overbased detergent having a TBN: % surfactant ratio (as hereinafter defined) of at least 11, preferably at least 13, provided that, when the said ratio is less than 13, the said total proportion of the phenol and the salicylic acid is at least 65 mass %.
By a “calcium overbased detergent” is meant an overbased detergent in which the metal cations of the basic metal-containing material are essentially calcium cations. Small amounts of other cations may be present in the basic metal-containing material, but typically at least 80 mole %, more typically at least 90 mole %, for example at least 95 mole %, of the cations in the basic metal-containing material, are calcium ions. Cations other than calcium may be derived, for example, from the use in the manufacture of the overbased detergent of a surfactant salt in which the cation is a metal other than calcium.
The percentage of surfactant in the overbased detergent, and the percentages of the individual surfactants, for example, phenol, in the surfactant system, are the percentages measured by the method set out below, which also indicates how the “standardized TBN” of an overbased detergent is determined.
1. Dialysis of the Overbased Detergent and Determination of Standardized TBN
A known amount (A g, approximately 20 g) of the liquid overbased detergent (substantially free from other lubricating oil additives) is dialysed through a membrane in a Soxhlet extractor (150 mm height×75 mm internal diameter) using n-hexane siphoning at a rate of 3 to 4 times per hour for 20 hours. The membrane should be one which retains substantially all the metal-containing material, and passes substantially all the remainder of the sample. An example of a suitable membrane is a gum rubber membrane supplied by Carters Products, Division of Carter Wallace Inc., New York, N.Y. 10105 under the trade name Trojans. The dialysate and residue obtained on completion of the dialysis step are evaporated to dryness, any remaining volatile material then being removed in a vacuum oven (100° C. at less than 1 torr or less than about 130 Pa). The mass of the dried residue, in grams, is designated B. The percentage (C) of overbased detergent material in the liquid sample is given by the equation:
C
=
B
A
×
100
%
The “standardized TBN” of the overbased detergent (that is, the TBN expressed in a manner which is independent of the amount of diluent) is the TBN measured according to ASTM D2896 on the dried residue.
Background information for the dialysis technique is given by Amos, R. and Albaugh, E. W. in “Chromatography in Petroleum Analysis”, Altgelt, K. H. and Gouw, T. H., Eds, pages 417 to 422, Marcel Dekker, Inc., New York and Basel, 1979.
2. Determination of TBN: % Total Surfactant Ratio
A known amount (D g, approximately 10 g) of the dried residue is hydrolyzed as specified in sections 8.1 to 8.1.2 of ASTM D3712, except that at least 200 ml of 25% by volume hydrochloric acid (sp. gr. 1.18) is used in section 8.1.1. The amount of hydrochloric acid used should be sufficient to effect acidification/hydrolysis of the overbased detergent residue into organic materials (surfactants) and inorganic materials (calcium-containing materials, for example, calcium chloride). The combined ether extracts are dried by passing them through anhydrous sodium sulphate. The sodium sulphate is rinsed with clean ether, and the combined ether solutions are evaporated to dryness (at approximately 110° C.) to yield a hydrolyzed residue. The mass of the dried hydrolyzed residue, in grams, is designated E.
The percentage, Y, of total surfactants in the original liquid overbased detergent is given by the equation
Y
=
E
D
×
C
and the TBN: % total surfactant ratio, X, is given by the equation
X
=
TBN
of the liquid overbased detergent
Y
It will be noted that, in determining X, the mass of the surfactants in their free form (that is, not in the form of a salt or other derivative) is used. For brevity, X will in general be referred to herein as the “TBN: % surfactant ratio”, and it is the value of X that is specified under this term in the claims and elsewhere in this specification.
3. Determination of Individual Surfactants (in their free form) in the Surfactant System
The techniques described below isolate the individual surfactants, in hydrolyzed form, from the hydrolyzed surfactant mixture derived from the overbased detergent. As indicated below, the proportion of each individual surfactant is the proportion by mass of the individual surfactant, in hydrolyzed form, in the hydrolyzed surfactant mixture. Thus, where, for example, the overbased detergent contains a calcium phenate/sulphonate/salicylate surfactant system, the proportions of the individual surfactants in the surfactant system are expressed as the proportions of phenol, sulphonic acid and salicylic acid respectively.
The proportions of individual surfactants may be
Lenack Alain Louis Pierre
Skinner Philip
Infineum USA L.P.
Ogden Necholus
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