Solid anti-friction devices – materials therefor – lubricant or se – Lubricants or separants for moving solid surfaces and... – Heterocyclic ring compound; a heterocyclic ring is one...
Reexamination Certificate
2000-10-20
2002-04-02
McAvoy, Ellen M. (Department: 1764)
Solid anti-friction devices, materials therefor, lubricant or se
Lubricants or separants for moving solid surfaces and...
Heterocyclic ring compound; a heterocyclic ring is one...
C508S231000, C548S142000
Reexamination Certificate
active
06365557
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to 2,5-dimercapto-1,3,4-thiadizaole dimer reaction products and adducts useful as extreme pressure additives, and more particularly to 2,5-dimercapto-1,3,4-thiadiazole dimer/glycol reaction products and adducts useful as extreme pressure additives.
BACKGROUND OF THE INVENTION
A variety of additives are used in lubricants to substantially improve performance. For example, extreme pressure additives are routinely incorporated into an untreated lubricating composition (e.g., greases) to significantly improve performance. Extreme pressure additives are believed to produce a film on the surface of a metal which can both increase the load carrying capacity of lubricant, and protects the metal surface under high load conditions from deterioration due to wear, welding, and abrasion.
Lead naphthenates and lead dialkyldithiocarbamates are frequently used as additives to improve the EP performance of greases. However, lead is a heavy metal which is considered “poisonous” in all forms. As an alternative, metal additives (such as antimony, zinc, and bismuth) have been used as a replacement for lead. However, these heavy metals still provide environmental concerns regarding the use. Accordingly, it has long been a goal in the art to develop non-metal lubricating materials to replace heavy metal additives while providing acceptable extreme pressure performance.
The effectiveness of potential extreme pressure additives is conventionally ascertained by the 4-Ball Weld Test (ASTM D-2596) and the Timken Load Test (ASTM D-2509). An ideal candidate compound should exhibit good results in both tests since each test quantitates different extreme pressure properties.
Known to those skilled in the art 2,5-dimercapto-1,3,4-thiadiazole (DMTD) derivatives are effective as anti-wear additives in lubricants. Examples of DMTD derivatives useful as anti-wear additives include the monosulfide and disulfide dimers of DMTD as disclosed in U.S. Pat. Nos. 4,517,103 and 5,194,621, maleate adducts of DMTD as disclosed in U.S. Pat. Nos. 5,102,568, 5,055,584 and 5,138,065 and mono-alkylated and thioacteal derivatives as disclosed in U.S. Pat. No. 5,849,925.
DMTD derivatives are also known to provide good 4-Ball Weld properties. In fact, the 4-Ball Weld properties of DMTD derivatives often exceed commercial requirements. Unfortunately, these same derivatives generally exhibit poor Timken Load performance since the DMTD derivatives do not generally provide Timken Loads levels greater than 35 pounds. As a result, commercialization of DMTD derivatives as extreme pressure additives has been limited.
In view of the above, there exists a need in the art for DMTD derivative that provide both adequate 4-Ball Weld and Timken Load properties. Accordingly, it is an object of the present invention to provide DMTD derivatives that provide adequate 4-Ball Weld and Timken Load properties, which will allow for the effective utilization of DMTD derivatives as extreme pressure additives.
SUMMARY OF THE INVENTION
The present invention provides 2,5-dimercapto-1,3,4-thiadiazole dimer/glycol reaction products and adducts useful as extreme pressure additives. In one embodiment, an additive is provided including the reaction product of:
where Z is hydrogen, an alkyloxy linkage having formula (II):
where F is a hydroxyl radical, a branched or straight chain C
1
to C
20
alkoxyl radical, a branched or straight chain C
1
to C
20
alkylcarboxyl radical, a mono-substituted, di-substituted, or tri-substituted glycerol residue, hydrogen, or combinations thereof; where R
3
is hydrogen, a methyl radical, or combinations thereof; where R
4
is hydrogen, a branched or straight chain C
1
to C
20
alkyl radical, a phenyl radical, a C
1
to C
8
branched or straight chain alkyl-substituted-phenyl radical, a C
1
to C
20
branched or straight chain acyl radical, or combinations thereof; and with q being 1 to 300.
In another embodiment, an additive is provided including mono-substituted and di-substituted thiadiazole condensation adducts having formulas (IV) and (V), respectively:
in which R
1
, R
3
and R
4
are independently selected from the above-described group of substituents for the reaction products and n is 1 to 2. The number of repeating ether units “m” in the glycol moiety is 1 to 50.
In another embodiment, an additive is provided including the reaction product of: (A) a thiadiazole dimer having formula (VI):
where d is 1 to 5 and Z is hydrogen, an alkyloxy linkage having formula (II):
or combinations thereof, with R
1
being hydrogen, a branched or straight chain C
1
to C
7
alkyl radical, or combinations thereof and R
2
being hydrogen, a branched or straight chain C
1
to C
7
alkyl radical, or combinations thereof, wherein t is 0 or 1; and
(B) a poly(ether)glycol having formula (III):
In an alternative embodiment, an additive is provided including the reaction product of:
(A) a thiadiazole compound being
or combinations thereof, where Z is hydrogen, an alkyloxy linkage having formula (II):
or combinations thereof, with R
1
being hydrogen, a branched or straight chain C
1
to C
7
alkyl radical, or combinations thereof and R
2
being hydrogen, a branched or straight chain C
1
to C
7
alkyl radical, or combinations thereof, where n is 1 to 2 and t is 0 or 1; and
(B) a poly(ether)glycol having formula (III):
where F is a hydroxyl radical, a branched or straight chain C
1
to C
20
alkoxyl radical, a branched or straight chain C
1
to C
20
alkylcarboxyl radical, a mono-substituted, di-substituted, or tri-substituted glycerol residue, hydrogen, or combinations thereof; where R
3
is hydrogen, a methyl radical, or combinations thereof; where R
4
is hydrogen, a branched or straight chain C
1
to C
20
alkyl radical, a phenyl radical, a C
1
to C
8
branched or straight chain alkyl-substituted-phenyl radical, a C
1
to C
20
branched or straight chain acyl radical, or combinations thereof; and where q is 1 to 300.
Lubricating compositions including the reaction products and adducts of the present invention are also provided. Advantageously, the lubricating compositions of the present invention exhibit significantly improved Timken loads as compared previous DMTD derivatives. These and other advantages of the present invention will be readily apparent from the detailed description set forth below.
DETAILED DESCRIPTION OF THE INVENTION
Present invention provides reaction products and adducts of substituted-2,5-dimercapto-1,3,4-thiadiazole dimers (hereinafter “thiadiazole dimers”) and poly(ether)glycols useful as extreme pressure additives in lubricants. The thiadiazole dimer-glycol reaction products and adducts have unexpectedly been found to provide good Timken Load properties in addition to good 4-Ball Weld properties. In addition, the reaction products and adducts are biodegradeble at low concentrations. Advantageously, the reaction products and adducts provide a more environmentally-friendly alternative to the heavy metal extreme pressure additives commonly used in lubricants.
In one embodiment the present invention provides an additive including a reaction product of a thiadiazole dimer and a poly(ether)glycol. The thiadiazole dimer is a 2,5-dimercapto-1,3,4-thiadiazole (DMTD) monsulfide or disulfide dimer having formula (I):
in which “n” is 1 to 2 and the substituent “Z” is either: (1) hydrogen; (2) an alkyloxy linkage having formula (II):
or combinations thereof. When Z is an alkyloxy linkage, “t” is 0 or 1 and the substituent R
1
is either: (1) hydrogen; (2) a branched or straight chain C
1
to C
7
alkyl radical, with a C
1
to C
4
alkyl radical being preferred; or a combination thereof. Likewise, the substituents for R
2
are independently chosen from the same group of substituents described for R
1
. In a preferred embodiment, when Z is an alkyloxy linkage “t” is 0, R
1
is an ethyl radical and R
2
is a propyl radical.
Thiadiazole dimers falling within the above-described parameter are known in the art and are easily synthesized following known techniques. For examp
Karol Thomas J.
Tepper Ronald J.
McAvoy Ellen M.
Norris McLaughlin & Marcus P.A.
R.T. Vanderbilt Company, Inc.
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