Note: Descriptions are shown in the official language in which they were submitted.
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A LUBRTCANT COMPRTSlNG AN AL~ SUBSTITUTED NAP~T~IALINE AND AN ESTER
The present invention relates to lubricant comprising an ester. More
particularly, the invention relates to high temperature chain oils having
improved volatility and functional life.
Lubricant compositions for use on drive chains, particle board presses, tenter
frames and stenter frames require viscosity stability.
Prior lubricant compositions, which have included esters, have not been
satisfactory for use with drive chains at high temperatures due to the viscositychange experienced by esters at high temperatures. Although compositions
employing polyalphaolefins do not exhibit the same viscosity change
experienced by esters, oils having polyalphaolefins also have not proven
satisfactory due to the tendency to form varnish under thin film conditions.
Other deficiencies of prior lubricant compositions include unacceptable
volatility and inadequate functional lifetime.
The present invention overcomes these and other disadvantages by including
an alkyl-substituted naphthalene in a lubricant composition having an ester.
One object of the present invention is the provision of a lubricant for use withdrive chains and other chain mechanisms operating in high temperature
environments having improved viscosity characteristics.
Another object of the invention is to provide a high temperature chain oil
having improved volatility characteristics and an increased functional life.
The lubricant composition of the present invention comprises an
alkyl-substituted naphthalene and an ester. In referring to an alkyl-substitutednaphthalene, it is contemplated that reference is made to naphthalene
.
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substituted with one or more straight or branched alkyl groups of varying
lengths.
The inclusion of one or more alkyl-substituted naphthalene compounds in a
lubricant composition having an ester results in unexpected improvements,
such as an increase in the functional life of the oil, as well as a decrease in
the overall volatility of the oil.
The present invention comprises an amount of alkyl-substituted naphthalene
sufficient to improve the volatility of the lubricant composition. Alternatively,
the invention comprises an amount sufficient to increase the functional life of
the lubricant. Generally the alkyl-substituted naphthalene comprises from
about 10 percent to about 50 percent by weight of the lubricant composition,
alternatively from about 12 percent to about 30 percent. Unless otherwise
indicated, throughout this specification, the amounts of the components are
listed in percentages by weight of the total composition.
Esters which may be used in the present invention are disclosed in
Kirk-Othmer Encyclopaedia of Chemical Technology, (4th ed. 1994), vol. 9,
pp. 781-812, which is incorporated by reference herein. More particularly, the
present invention may comprise diesters, phthalates, trimellitates,
pyromellitates, dimer acid ester, polyols and polyoleates. It is contemplated
that trimellitic esters and polyols are particularly suitable. In certain
embodiments, an ester comprises from about 40 percent to about 90 percent
by weight of the lubricant composition, alternatively from about 50 percent to
about 80 percent.
EXAMPLES
The following examples provide a basis for understanding the nature of the
invention and are not limitations upon the scope of the invention. The
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examples below represent different embodiments of the invention having
different viscosity grades.
Example I Example ll
Emkarate 9130 70% 63.4%
Mobil MCP 968 15% 18%
Indopol H-1900 -- 16%
Parapol 1300 13 % --
lrgalube 349 0.6% 0.6%
Irganox L06 0.6% 1%
Vanlube SS 0 4 % 0.6 %
Nasul 707 0.4% 0.4%
Emkarate 9130 is a trimellitic acid ester, available from ICI Chemical
Polymers. Mobil MCP 968 is a mixture of dialkyl- and trialkylnaphthalenes,
available from Mobil Chemical Co. Parapol 1300 and Indopol H-1900 are
polybutene polymers. Irgalube 349 iS an antiwear additive available from
Ciba-Geigy PLC. Irganox L06 is an antioxidant, also available from
Ciba-Geigy PLC. Vanlube SS is an antioxidant available from RT Vanderbilt
Chemical Corp. Finally, Nasul 707 is an anti-corrosive agent available from
King Industries.
It is contemplated that in a commercial preparation of the embodiment
disclosed as Example 1, the specified amounts of Emkarate 9130 and Mobil
MCP 968 are combined and heated to a temperature of from about 70~C to
about 85~C. Subsequently, Parapol 1300 (or Indopol H-1900), Irganox L06
and Vanlube SS are blended into the mixture. Irganox L06 and Vanlube SS
are powders which must be melted into the mixture, and the mixture must be
blended until the Irganox L06 and Valube SS are thoroughly dispersed in the
mixture. The temperature of the composition is then lowered to about 60~C
and Irgalube 349 and Nasul 707 are blended into the composition.
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Samples of the lubricant compositions of the preceding Examples were
prepared in accordance with the steps outlined in the preceding paragraph.
To assess the volatility of the composition, the isothermal evaporation of
several samples was measured by subjecting a sample to the constant
temperature in an instrument specifically designed for thermo-gravimetric
analysis by TA Instruments. In the results below, "t90" represents the time at
which 10 percent by weight of the original sample had volatized (i.e., 90
percent by weight of the sample remained), and "T50" indicates the time at
which 50 percent by weight of the original sample had volatized (i.e., 50
percent by weight of the sample remained).
Example I Example ll
200~C t90 > 10 hours > 10 hours
t50 > 10 hours > 10 hours
225~C t90 2.2 hours 3.5 hours
t50 > 10 hours > 10 hours
250~C t90 0.60 hours 1.3 hours
t50 3.3 hours 5.5 hours
275~C t90 0.31 hours 0.35 hours
t50 1.3 hours 1.3 hours
These test results show the beneficial and improved volatility characteristics
of the present invention.
The superiority of the present invention can be seen by comparing the
volatility characteristic of Example I with the volatility characteristics of a
sample (Formula B) which does not include an alkyl naphthalene compound.
Formula B is comprised of:
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Emkarate 9130 85%
Mobil MCP 968 --
Parapol 1300 13%
I rgalube 349 0.6%
Irganox L06 0.6%
Vanlube SS 0.4%
Nasul 707 0.4%
Formula B has the same ingredients in the same amounts as Example I
except that in place of Mobil MCP 968 (a mixture of dialkyl- and
trialkyl-naphthalenes), Formula B has additional Emkarate 9130 (a trimellitic
acid ester). Isothermal scans on 10 to 12 mg samples of Example I and
Formula B were run at four different temperatures. The following results
indicate the time at which 50 percent by weight of the original sample had
volatized at each of the four temperatures (i.e. 50 percent by weight of the
sample remained) .
Example I Formula B
225~C t50 ~ 10 hours 7 hours
250~C t50 3.3 hours 2.4 hours
275~C t50 1.4 hours 0.6 hours
300~C t50 0.25 hour 0.20 hour
At each of the tested temperatures, the lubricant of Example I took longer to
volatilize to the extent where fifty percent of the lubricant was no longer
present. These results demonstrate that the invention's improvement of
volatility can be observed over a wide temperature range.
The lubricant composition of the present invention is notable for its ability tomeet the demands of use of high temperature drive chain applications.
However, the present invention is also suitable for use in other applications,
. .
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such as gears and air compressors, as well as for any lubricant application
where low volatility and increased functional life are desirable.
The above specification, examples and data provide a basis for
understanding and using the disclosed invention. However, any embodiment
of the invention within the scope of the disclosure is within the spirit and
scope of the invention.
