Solid anti-friction devices – materials therefor – lubricant or se – Lubricants or separants for moving solid surfaces and... – Organic -co- compound
Reexamination Certificate
1995-08-02
2002-11-05
Medley, Margaret (Department: 1714)
Solid anti-friction devices, materials therefor, lubricant or se
Lubricants or separants for moving solid surfaces and...
Organic -co- compound
C508S472000, C252S079000
Reexamination Certificate
active
06475964
ABSTRACT:
BACKGROUND OF THE INVENTION
Field of the Invention
The invention relates to motor oils having high dispersivity (dispersing power) and good wear protection characteristics.
DISCUSSION OF THE BACKGROUND
As an internal combustion engine is operated, there is a tendency for the concentration of oil-insoluble combustion products to build up in motor oil. The combination products include resin- and asphalt-containing products, and other impurities (collectively referred to as “sludge”) (see 1990, “Ullmann's Encyclopedia of Industrial Chemistry”, 5th Ed., Vol. A15, pub. VCH, pp. 448-450).
It has been known for some time that dispersivity and detergency can be promoted with the use of oil-soluble polymer additives containing units of functional monomers incorporated by, e.g., ordinary co-polymerization or graft polymerization (see 1967, Rauch-Puntigam, H. and Voelker, Th., “Acryl- und Methacrylvergindungen”, pub. Springer-Verlag, pp. 315-316; Ger. OSs 28 32 406, 25 56 080, 26 34 033; U.S. Pat. Nos. 3,088,931, 3,089,832, 3,879,304, 4,146,489, etc.). Also, nitrogen-containing polymer additives have been found to have good dispersive effects; however, their wear protection and detergent characteristics are unsatisfactory.
These so-called “ashless dispersants” are therefore generally used in combination with additional, metal-salt-containing additives, supplied in “packages” (see Bartz, W. J., “Additive fuer Schmierstoffe”, pub. Curt R. Vincentz Verlag, pp. 65-67). Important components used are zinc dialkyldithio-phosphates (ZnDDP), which have anti-wear and antioxidant properties as well as metal containing detergents. Such metal containing additives decompose with formation of ash, as would be expected. The ash along with other residues from the motor oils becomes increasingly detrimental to the engine as the service time increases.
In practice obvious attempts have been made to employ both types of additives simultaneously—the polymer additives and the “packaged” formulations comprising the metal-salt-containing additives. Accordingly, compatibility of the two types of additives is an important issue. Strongly polar substituents, particularly basic substituents, on the radial sealing ring additives, m ay also lead to problems with radial sealing ring materials.
There has been a search for polymer additives with substituents which provide less polarity. U.S. Pat. No. 3,198,739 discloses copolymers of long-chain (meth)acrylic acid esters and omega-hydroxyalkyl esters of (meth)acrylic acid with alpha-olefins or vinyl- or allyl esters. The outstanding detergency of such copolymers has been described. In U.S. Pat. No. 3,001,942, it is stated that the object of the invention is to devise lubricating oil additives having improved detergency, wherewith metal-containing ash does not occur in the sediment from said additives. The described additives are comprised of copolymers of long-chain (meth)acrylic acid alkyl esters and monoesters of polyoxy-1,2-alkylene glycols with lower aliphatic &agr;,&bgr;B-unsaturated monocarboxylic acids.
In Fr. Pat. 1,173,356, additive preparations are described which are comprised of units of ethylenically unsaturated aliphatic monomers having 4-30 aliphatic C atoms, esters of &agr;,&bgr;-unsaturated mono- or dicarboxylic acids with polyalkylene glycols having 2-7 C atoms, and alkyl ethers thereof, and which contain polar groups having hydroxy- and/or amino substituents. Copolymers of
long-chain (meth)acrylic acid esters and
(meth)acrylic acid monoesters of polybasic alcohols are employed, e.g., in U.S. Pat. No. 3,377,285; and &bgr;-hydroxyethyl ester forms are employed in Fr. Pat. 2,069,681 and Brit. Pat. 1,333,733.
In Eur. Pat. 0,418,610 (U.S. Pat. No. 5,188,770), agents for improving the viscosity index (VI) are described, which agents have dispersant action and contain polyalkyl (meth)acrylate (PAMA) polymers based on long-chain alkyl (meth)acrylates and functionalized (meth)acrylic acid alkyl esters from the group of the hydroxyalkyl esters and the multiply alkoxylated alkyl esters, in combination with olefin copolymers and/or HSD copolymers and/or hydrogenated polyisoprene or polybutadiene.
A need has continued to exist for a way of devising additive-containing motor oils having high dispersivity and good wear protection characteristics, in which the content of nitrogen-containing dispersants and ash-forming phosphorus-containing and metal salt-containing additives in said motor oils is substantially less than the customarily used and recommended concentrations.
SUMMARY OF THE INVENTION
Accordingly, one object of the present invention is to provide additive-containing mineral oils.
The invention relates to polymeric-additive-containing motor oils and transmission oils of the commercial SAE single-and multiple viscosity classes, which oils have high dispersivity and good wear protection characteristics and which comprise the following additives:
(i) heavy-duty additives (HD additives) of types which are per se known, having a certain content of zinc compounds, particularly zinc dialkyl phosphorodithioates (ZnDDP), as antioxidants and wear protection agents (see 1989
Erdaas und Kohle
, 42(10):402-404; and Kirk-othmer, 1981, “Encyclopedia of Chemical Technology”, 3rd Ed., pub. J. Wiley, Vol. 14, pp. 492-493); and
(ii) as dispersive polymeric components PC, cooligomers and/or copolymers comprised of
(a) units of alkyl (meth)acrylates of formula I
where R represents hydrogen or methyl, and
R
1
represents an alkyl group with 4-34 C atoms, preferably 6-24 C atoms, more preferably 8-22 C atoms, said units of formula I being present in the amount of 60-99.5 parts by weight (based on the total weight of monomers in PC), and
(b) units of at least one functionalized alkyl (meth)acrylate of formula II
where R′ represents hydrogen or methyl, and
R
2
represents an alkyl group having 2-6 C atoms and substituted with at least one OH group, or R
2
represents a multiply alkoxylated group
where R
3
and R
4
represent hydrogen or methyl,
R
5
represents an alkyl or alkaryl group having 1-40, preferably 1-18 C atoms, and
n represents an integer in the range 1 to 60, preferably 1 to 40, wherewith if n ≧2 then R
5
may represent hydrogen, said units of formula II being present in the amount of 0.5-40 parts by weight (based on the total weight of monomers I and II), further,
(c) units of one or more monomers of formula III
where R″ represents hydrogen or methyl, and
R
6
represents an alkyl group with 1-5 C atoms, said units of formula III being present in the amount of 0-20, preferably 0.5-15, particularly preferably 1-12 parts by weight (based on the total weight of monomers I and II), and
(d) units of 1-alkenes of formula IV
CH
2
=CHR
7
(IV)
where R
7
represents an alkyl group having 4-40, preferably 4-24 C atoms, said units of formula IV being present in the amount of 0-50 parts by weight (based on the total weight of monomers I and II); with the following provisions:
(1) the units of formulas I and II together comprise 100 wt. %,
(2) the content of polymer components PC in the additive-containing mineral oils is in the range 0.5-50 wt. %, and
(3) the content of phosphorus, particularly in the form of zinc dialkyl phosphorodithioate(s) (ZnDDP), in the additive containing mineral oils is less than or equal to 0.1 wt. %, preferably less than or equal to 0.08 wt. %.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The molecular weight of the cooligomers CM according to the invention is in the range 1,000-25,000 Dalton, preferably 1,500-15,000 Dalton; and the molecular weight of the copolymers CP according to the invention is in the range 30,000-500,000, preferably 30,000-150,000 Dalton (determined by gel permeation chromatography—see Mark, H. F., et al., 1987, “Encyclopedia of Polymer Science and Technology”, Vol. 10, pub. J. Wiley, 1-19).
Of particular interest are cooligomers CM and copolymers CP wherein the monomers of formula I are comprised of units of (meth)acrylic acid esters having 4-34, preferably 6-24 C atoms, more prefer
Neudoerfl Peter
Pennewiss Horst
Renner Gerhard
Medley Margaret
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Roehm GmbH & Co. KG
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