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
1999-07-21
2001-05-29
Medley, Margaret (Department: 1714)
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...
C508S400000
Reexamination Certificate
active
06239084
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to viscosity drift control in overbased detergents, principally overbased sulfonates and phenates. The invention move specifically relates to the method and composition for controlling viscosity drift in a detergent in storage prior to incorporation in a finished lubricating oil.
2. Background and Discussion of the Prior Art
Overbased detergents are extensively used in lubricating oils. Generally, the overbased detergent is shipped and stored prior to incorporation in the lubricating oil. The storage and shipping conditions often expose the detergent to temperatures substantially above ambient for long periods of time. It was found that overbased detergents would, over time, and under elevated temperatures, increase in viscosity. This viscosity increase or drift caused the overbased detergent to be out of specification with the initially specified viscosity, and in certain cases the viscosity of the stored overbased detergent had sufficiently increased so as not to be useful for blending in the lubricating oil. The lubricating oil art was directed away from overbased detergents having high viscosities because of handling and filter ability problems, as discussed in U.S. Pat. No. 5,011,618 to Papke et al and U.S. Pat. No. 4,387,033 to Lenack et al.
Overbased calcium sulfonate detergents were generally required to have a viscosity of no more than about 200 to 250 cSt at 100° C., but after several weeks of storage particularly under elevated temperatures, the detergent viscosity would drift to 400 cSt at 100° C. or more. The increased or high viscosity overbased calcium sulfonate was then unsuitable for blending and use in lubricating oils.
While it was known in the lubricating oil art to add certain alkyl phenols and vegetable oils to finished blended lubricating oils to enhance certain performance characteristics, it was not known that limited amounts of such additives when added to an overbased detergent per se in contradistinction to a lubricating oil effectively controlled viscosity drift in long term storage of the detergent prior to blending the detergent in a lubricating oil.
The art directed to processes for producing overbased detergents recognized that certain alkyl phenols could be used as co-promoters, as disclosed in Burnop, U.S. Pat. No. 4,104,180. Where alkyl phenols were used as co-promoters, the overbased detergent co-promoter reaction product had no effect as a viscosity drift control agent, The alkyl phenol co-promoter detergent would undergo substantial viscosity drift in storage.
The overbased detergent art desired a viscosity drift control agent or system which reduced or eliminated viscosity drift of the detergent in storage.
The term “viscosity drift” as used hereinbefore and hereinafter means the change (increase) in viscosity over time. The term “viscosity drift control” as used hereinbefore and hereinafter means the reduction in the change (increase) in viscosity over time. The term “additive amount(s)” as used hereinbefore and hereinafter means about 0.1 to 5.0% by weight.
SUMMARY OF THE INVENTION
A viscosity drift control system for overbased detergents is achieved by adding additive amounts of a compound having an oleophilic group and having secondary hydroxyl functionality to an overbased detergent in storage and prior to incorporation in a finished lubricating oil. This viscosity drift control additive or agent of the present invention when added in additive amounts to the overbased detergent results in a viscosity which over several weeks at elevated temperatures remains relatively unchanged or slightly elevated, whereas absent the agent, the viscosity would over time increase to wherein the detergent is commercially unacceptable. The agent of the present invention permits the overbased detergent to remain in specification so as to be useful in a finished oil.
The viscosity drift control agent of the present invention is effective in additive amounts of 0.1 to 5% by weight and preferably 0.25 to 1.0% by weight in the overbased detergent. These additive amounts of the viscosity drift control agent reduce viscosity drift to less than a 10% increase in the initial viscosity over a period of 4 weeks at elevated temperatures above about 35° C.
The viscosity drift control agent generally includes at least one of: (1) vegetable oils, (2) carboxylic acids and (3) alkyl phenols.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In one aspect the present viscosity drift control system is a method for controlling viscosity drift in a detergent which includes providing an overbased detergent subject to viscosity drift and adding an additive amount of a viscosity drift control agent having an oleophilic group and secondary hydroxyl functionality, and storing the detergent prior to incorporation in a finished lubricating oil, whereby the detergent viscosity drift is reduced.
In another aspect, the viscosity drift control agent of the present invention includes generally three classes of compounds having an oleophilic group and secondary hydroxyl functionality, as further discussed hereinafter. It is to be understood that such secondary hydroxyl functionality pursuant to the present invention contemplates OH, OH—HO hydrogen bonding as in inter-fatty acid triglyceride hydrogen bonding (e.g., vegetable oils), and OH in the ester form of this functional group. The viscosity drift control agents are preferably of moderately high molecular weight (MW). The viscosity drift control agents have a molecular weight of about 150 to 1,000 or more, and preferably between about 260 and 1,000.
It has been found that three classes of compounds fall within the aforesaid definition of viscosity drift control agents pursuant to the present invention. These classes of viscosity drift control agents are (1) vegetable oils, (2) carboxylic acids and (3) alkyl phenols, having an oleophilic group and further having secondary hydroxyl functionality. Suitable vegetable oils include canola oil, jojoba oil, sunflower oil, rapeseed oil, linseed oil, palm kernel oil, castor oil and hydrogenated castor oil, and the like. Vegetable oils such as canola oil and jojoba oil are preferred. The alkyl phenols include mono, di, linear and branched alkyl phenols. The alkyl group of the alkyl phenol may have up to 40 carbon atoms, and preferably 6 to 20 carbon atom. Useful alkyl phenols including mono, di and tri substituted alkyl phenols. Examples of useful alkyl phenols are heptyl phenols, octylphenols, dodecylphenols, nonylphenols and cyclohexyl phenols. It is to be understood that the terms “alkyl phenol” or “alkyl phenols” are used herein to represent one or more such alkyl phenols. Dinonyl phenol is a preferred alkyl phenol. Suitable carboxylic acids pursuant to the present invention include mono hydroxy alkane carboxylic acids having from 8 to 18 carbon atoms or higher wherein the hydroxyl group is, by way of example, in the beta, gamma or delta or further substituted position with respect to the carboxyl group, such as hydroxy caprylic acids, hydroxy lauric acids, hydroxy myristic acids, hydroxy palmitic acids, hydroxy stearic acids, and hydroxy arachidic acids as well as their homologs and analogs. A 12-hydroxy stearic acid is a preferred carboxylic acid. It is to be noted that the aforesaid useful compounds contain both an oleophilic group and secondary hydroxyl functionality.
The viscosity drift control agent is effective in amounts of 0.1 to 5% by weight and preferably 0.25 to 1.0%. The viscosity drift control effect is generally proportional to the amount of agent added to the detergent. The viscosity drift effected by additive amounts of the control agents of the present invention is less than about 10% over 4 weeks. That is, the initial viscosity of the combination of the overbased detergent and control agent increases or drifts less than about 10% over 4 weeks. The controlled viscosity drift is generally about 5 to 25 cSt at 100° C., where 0.1 to 5 % by weight of the control agent is added to the overbased detergent and
Eliades Theo I.
Matthews Leonard A.
Muir Ronald J.
Crompton Corporation
Ma Shirley S.
Medley Margaret
LandOfFree
Viscosity drift control in overbased detergents does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Viscosity drift control in overbased detergents, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Viscosity drift control in overbased detergents will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2441232