Note: Descriptions are shown in the official language in which they were submitted.
~ 60SI-121
LZ~
The present invention relates to a silicon lubricant
composition and more specifically the present invention
relates to a silicone lubricant composition for lubricating
hard metal surfaces or soft metal surfaces such as copper
or bronze.
Silicone lubricants are well known for hard metal
surfaces. Such silicone lubricants usually comprise an
organopolysiloxane polymer which may be dimethylpoly-
siloxane polymer, a methyl, higher-alkyl substituted poly-
1 ~ siloxane polymer-~ chlorophenyl or tetrachlorophenyl sub-
stituted polysiloxane polymer. Also, there are silicone
lubricants in which the base lubricating fluid is composed
of a trifluoropropyl substituting organopolysiloxane polymer.
These fluids may be utilized by themselves or with various
other additives for the lubrication of metal surfaces. For
instance methyl, higher-alkyl substituted organopoly-
siloxane polymers are very effective for lubricating hard
metal surfaces. In addition dimethylpolysiloxanes with
~arious chlorinated additives are also known for lubricating
hard metal surfaces such as for instance disclosed in
Agens U.S. Patent No. 2,837,482 dated June 3, 1958. Such
chlorinated additives are described in the foregioing Agens
Patent consist of octyltetrachlorobenzoate, dioctyl-tetrachloro-
phthalate and bis-2-ethylhexyl tetrachlorophthalate. In
addition various types of chlorinated phthalates car, be
utilized as additives for dimethylpolysiloxanes such as
bis-2-al~ylhexyltetrachlorophthalates. In these compounds
the alkyl may contain anywhere from 2 to 8 carbon atomsc
As one examp]e for instance the methyl~ higher-alkyl substitu-
ted polysiloxanes have been shown to be effective as a lub-
ricant for hard metals or any metal if they have a film
thickness three times the surface roughness which for most
.
60SI-121
hard metal surfaces would require Eilm thickness of 30 ~o
45 micro inches. Most silicone lubricants and specifically
methyl, higher-alkyl substituted polysiloxanes have a film
thickness from 20 to 30 micro inches. Accordingly, what
happens with hard metals is that the methyl higher-alkyl
substituted polysiloxanes allows a slow attrition of the
asperities in the metal surface and an improvement of the
metal surface to a roughness of 5 micro inches which depth
of surface roughness can be handled by the methyl higher-
alkyl substituted polysiloxanes to lubricate such hard
metal surfaces. For dimethylpolysiloxanes which are not
as effective as the methyl higher-alkyl substituted poly-
siloxanes in lubricating metal surfaces, it is necessary
to also add a chlorinated additive. Conventional chloride
additives may also be added to methyl tetrachlorophenyl
substituted polysiloxanes to form ferrous chloride hydrate
compounds at the surface of the hard metal which is being
lubricated so that the oxy chloride will shear off under
stress and prevent undue wear against the hard metal surface.
Accordingly in summary, it has been found out that methyl
higher-alkyl substituted polysiloxane with or without
additives will function in most cases as an effective
lubricant for hard metals the dimethylpolysiloxane lubricants
will function as lubricants for hard metals with the addition
of chloride additives and that tetrachlorophenyl substituted
polysiloxanes will function to some extent wikhout additives
in lubricating hard metal surfaces but will ~unction most
effectively with the use of chlorinated additives in the
lubrication of hard metal surfac~es. The reason the dime-
thylpolysiloxane polymers and the tetrachlorophenyl sub-
stituted polymers need the additives, is that they do not
form as an effective thickness of film on the hard metal
-- 2 --
: ' .. ' ..
60SI-121
L24
surfaces as is possible with the methyl higher-alkyl sub-
stituted polysiloxanes. However, all of these oryano-
polysiloxane lubricants as well as others tha-t haven't been
mentioned above with or without the tra~itional chlorinated
additives have a serious deficiency when it comes to lubrica-
ting soft metals, such as brass, bronze, soft steel, free
machining steel, lead, copper etc. In the case where the
organopolysiloxane polymers are applied to lubricate soft
metals, the wear rate is initially low and a low sliding
friction prevails then after a short period of low wear a
very high rate wear is experienced with a sizable increase
in the sliding friction causing the metal parts to wear
away at a higher rate.
It should also be pointed out that such chlorina-ted
additives such as those of the ~gens Patent are not as
effective as would be desired even with silicone polymers
in lubricating soft metals. When silicone lubricants are
applied to lubricate soft metal, even in the case with
methyl higher-alkyl substituted polysiloxanes that such
prior chlorinated additives have to be utilized at very
high concentrations of 4 to 10% by weight of the lubricating
composition to effect any sizable change in the performance
of the lubricant composition. Accordingly, it was highly
desirable to be able to formulate an additive which could
be utilized at small concentrations for addition to silicone
polymers to prepare silicone lubricant compositions for the
lubrication of soft metals. It was desired that such
silicone lubricant with the additive in it would form
oxychloride compounds on the soft metal surface and the
3Q_~ soft metal being in contact with another soft metal or
- ~ even a hard metal would ~ the oxychloride compounds to
shear off thus protecking the soft metal surface from wear.
-- 3 --
~ 60S~ 121
. .~ ~
Prior art chloride additives needed to be utilized at
high concentration as addi-tives to silicone lubricants,
since they were not very efficient in forming oxy chloride
compounds at the point of wear.
- Accordingly, it was thought it would be highly
advantageous to obtain some type of chlorinated additive
for such silicone lubricant which would form the appropriate
type of oxychloride compounds which were needed for soft
metal surfaces such as copper and bronze. Then the oxych-
loride compounds would be sheared off instead of the soft
metal and allow the soft metal to wear gradually and not
at a high rate as was experienced previously. Accordingly,
it was highly desirable to formulate and obtain an additive
for silicone polymers utilized in forming lubricant
compositions which such additive would decrease the wear
of hard metal surfaces but would more importantly decrease
the wear of soft metal surfaces when they acted upon
each other or when a soft metal surface acted against a hard
metal surface. It should be noted that the foregoing
discussion a~ove as to the formation of oxychloride com-
pounds at the surfaces of the metals and the function of
A~
such compounds preventing undue~r is a theoretical
discussion.
In summary, what was needed was chlorinated additive
or other type of additive for polysiloxane polymers that
could be utilized as a~ lubricant to decrease the wear of
metal surfaces acting against each other, which was much
more efficient that the prior art organopolysiloxane poly-
mers with various additives such as those instance dis-
,- ~
closed in the foregoing Agens U.S. Patent No.2,837,482
dated June 3, 1958.
Accordingly, it is one object of the present invention
.~ .
60SI-121
to provide for an addltive for s.ilicone lubricants which
would decreases the wear of hard metal surfaces lubricated
by such silicone polymers.
It is another object of the present invention to provide
an additive for a silicone lubricating composition which
would decrease the wear when such silicone lubricants was
utilized to lubricate soft metal surfaces.
There is an additional object of the present invention
to provide for an additive for a silicone lubricant com-
position which would decrease the wear when such lubricant
composition was utilized to lubricate soft or hard metal
surfaces acting against each other.
It is yet an additional object of the present in-
vention to provide for a silicone lubricant composition
which has excellent lubricity properties for lubricating -
copper, bronze, and brass surfaces. These and other objects
of the instant invention are accomplished by the means of
the disclosure set forth herein below.
In accordance with the above object~ there is provided
hy the present invention a silicone lubrican-t composition
comprising 100 parts by weight of an organopolysiloxane
polymer having a viscosity varying from S0 to 50,000 centi-
poise wherein the organo groups are selected from the class
consisting of monovalent hydrocarbon radicals and halo-
genated hydrocarbon radicals wherein there is added to the
composition in an effective amount of a chlorinated phos- .
phite or phosphonate and more specifically from .01 to 1
part by weight of a chlorinated phosphite or phosphonate.
The most preferred phosphites and phosphonates for use in
~ 30 the instant composition is trischlorethylphosphite and
: bis chloroethyl phosphonate. Although, the instant ad-
ditives may be utilized in trace~ amoun~ as is desired for
-- 5 --
; 60SI-121
any type of silicone lubricant composition. It is most
specifically suited for addition to lubricant compositions
where the basic polymer is a dimethylpolysiloxane polymer
or an organopolysiloxane polymer with the organo groups
selected from methyl, tetrachlorophenyl or trifluoropropyl
or from a methyl, high-alkyl subs-tituted polysiloxane polymer.
The additive may be utilized by itself or in combination
with the well known chlorinated aaditives of the fore~
going Agens Patent. For methyl, higher-alkyl, and tet-
rachlorophenyl substituted polysiloxanes the chlorinatedadditives of the foregoing Agens Patent are not needed. In
the case of dimethylpolysiloxanes, the chlorinated additives
of the foregoing Agens Patent should be added along with
the phosphites and phosphonates of the instant case for
optimum efficiency while the additives of the instant
'! invention are disclosed primarily for the lubricating of
soft metals that is where either of the two surfaces are
soft metals it can also be utilized with advantage with
` hard metals, such as machine steel, tool steel, etc. The
preferred soft metals in which the present lubricant
composition can be used with repsect thereto are for instant
; copper, brass, bronze, lead, tin and other soft metal sur-
faces, soft steel, machine steel, aluminum, etc. It
should be noted while the instant case discloses only the
use of two specific phosphites or phosphonates any highly
chlorinated phosphites or with substitution which are
soluble ln *he organopolysiloxane base polymer as described
above may be utilized as additives in accordance with the
invention. For some reason which is not known the phosphite
or phosphonate ~ =3~ activates the chlorinated part of
the molecules, allowing it to form compounds at the surface
i~ of the soft metal, as it has been theoretically discussed
~ - 6 -
:
,~ . . ,
~ 60SI-121
discussed above. However they perform their function, it
has been found that the instant additives even in trace
amounts do effectively decrease the wear for soft metal
surfaces.
Phosphite and phosphonate lubricant addi-tives can be
added to any silicone lubricant or any silicone polymer
which is utilized as a lubricant to improve the lubricating
properties of the silicone polymer. Preferably such poly-
siloxanes may be any organopolysiloxane where the organo
to ~ ratio may vary from 1.9 to 2.57 and where the organo
groups are selected from monovalent hydrocarbon radicals
and halogenated monovalent hydrocarbon radicals. Accord-
ingly while i-t is preferred that such silicone polymer
be a linear polymer or essentially a linear diorganopoly-
siloxane polymer, nevertheless, they may be up to 10% in
such linear diorganopolysiloxane polymer of monofunctional
siloxy unit or trifunctional siloxy units. Most preferably,
the organopolysiloxane polymer is one embodiment of the
instant invention is a linear polysiloxane and more specifi-
cally a linear diorga~opolysiloxane polymer where the
organo to Si ratio varies from 1.9 to 2.01, where the
organo groups are selected from monovalent hydrocarbon
radicals and halogenated monovalent hydrocarbon radicals,
and the polymer has a viscosity that varies anywhere from
50 to 50, 000 centipoise at 25C. Generally the polymer
- may have a viscosity that may vary anywhere ~rom 25 or 50
to-100,000 centipoise viscosity at 25C, but more prefer-
ably the polymer has a viscosity that varies from 50 to
5G,000 centipoise at 25~C. The above specificities with
respect to the organopolysiloxane polymer apply to any of
the preferred organopolysiloxane polymers that will be
described below or that have been described above for
- 7 -
, ~ .
~ 6OSI-121
utilization as the basic silicone lubricant polymer of the
instant invention. Such organo substituent groups of such
polymers may generally be selected from monoyalent hydro-
carbon radicals and halogenated monovalent hydrocarbon
radicals such as, alkyl radicals, methyl, ethyl, propyl;
higher alkyl radicals such as, decyl, dodecyl and etc.,
mononuclear aryl radicals such as, phenyl, methylphenyl,
ethylphenyl; cycloalkyl radicals such as, cyclohexyl,
cycloheptyl, and etc., halogenated monovalent hydrocarbon
radicals such as, chlorophenyl, tetrachlorophenyl and ~ -
trifluoropropyl and various other radicals and substituent
groups for utilization in the polymers of the instant
case which are well known and established as organic sub-
stituent groups in silicone polymers. One preferred
lubricant for utilization in the instant case is where the
organo substituent groups in the diorganopolysiloxane
polymer are methyl such as a dimethylpolysiloxane polymer
of a viscosity anywhere from 25 centipoise to 100,000
centipoise or more preferably of a viscosity of 30 centi-
poise to 50,000 centipoise at 25C. Although such a polymer
may have some phenyl substitution, in the most preferably
form it does not have any phenyl substitution. Of course,
as mentioned, the above does not apply to chlorophenyl or
tetrachlorophenyl substituent groups since in anothPr
preferred embodiment of the instant case, the linear
diorganopolysiloxane polymer has a minor amount of chloro-
phenyl or tetrachlorophenyl substituent groups along with
methyl substitu~nt groups.
The dimethylpolysiloxane polymer is utilized as a
30 Iubricant in accordance with the instant invention to which
the phosphite and phosphonate additives of the instant case
are applied. It is also preferred to utilize 1 to 10 parts
-- 8 --
. . : . ~ . . ...... ... , : . ,, :
:: : : . . . .... ... . .
60SI-121
i I
L~'~ t
by weight of chlorinated benzoate or chlorinated phthalate
as disclosed in the foregoing Agens U.S. Patent No.2,837,482
dated June 3, 1958, in addition to the phosphite and phos-
phonate additives of the instant case. Such concentrations
of the chlorinated phthalate or chlorinated benzoate are
added per 100 parts of the linear diorganopolysiloxane polymer.
It has been found in accordance with the instant invention
that the lubricating compositions of the instant case have
the ma~imum lubricating properties when there is added to
such linear diorganopolysiloxane polymers and specifically
linear dimethylpolysiloxane polymers, the foregoing chlori-
nated benzoates and chlorinated phthalates in addition to
the phosphite and phosphonate additives of the instant
case. Generally, it is not desired to add more than 10
~` parts of the henzoate or phthalate since more than 10 pa~ts
is not soluble in the linear dimethylpolysiloxane polymer
and less than 1 part does not add any appreciable anti-
properties to the lubricating composition in com-
bination with the phosphite and phosphonate additives of
the instant case. Generally such chlorinated addi-tives
such as that disclosed in the foregoing Agens Patent,can
be any highly chlorinated benzoate or highly chlorinated
phthalate, and specifically tetrachlorinated benzoate
or tetrachlorinated phthalates. Specific preferred
additional additives of the foregoing Agens Patent for
utilization in the lubricating compositions of the instant
case are, for instance, octyltetrachlorobenzoate, diacty-
ltetrachlorophthalate, bis-2-ehtylhexyltetrachloroptha-
late and bis-~-butylheY.yltetrachlorophthalate. Generally
with respect to the phthalates, any bis-alkylhe~yltet-
rachlorophthalate may be utilized as an additive in the
instant case to provide for lubricating compositions with
_ g _
r
.~ . . . ~ ~ . .
. . '. . ' ' ., ', ' ' . ", ~
60SI-121
enhanced lubricating properties and antiwear properties for
soft metals as well as for hard metals.
.~ It should be noted that basically any of the linear
organopolysiloxane polymers of the instant case may be
utilized with the foregoing chlorinated phthalates and
benzoates with impxoved antiwear properties for hard metals.
However, such chlorina~ed benzoates and phthaltes are
effective for adding or imparting antiwear properties to
silicone lubricants for soft metals only at high con-
centrations. However, these chlorinated benzoates and
phthalates are disclosed in the instant case as additives
to silicone lubricant compositions in combination with
the phosphites and phosphonates of the instant case,
especially in the case of linear dimethylpolysiloxane
polymers.
In the case where the silicone lubricant polymer is
a linear methylchlorophenyl or tetrachlorophenyl sub-
stituted polysiloxane polymer within the above viscosity
ambients then the foregoing chlorinated benzoates and
phthalates may or may not be utilized as additives. Most
preferably they are utilized as additives in combination
with the phosphites and phosphonates of the instant case
: to impart to them optlmum antiwear properties for soft
metals for the lubricating compositions of the instant
case.
; In the case of mèthyl, high-alkyl substituted linear
polysiloxane polymers such chlorinated benzoates and
phthalates are not needed as antiwear additives when the
silicone lubricant composition compased of such methyl
higher-alkyl polymer is utilized to lubricate either
~ soft or hard metals. With the methyl higher-alkyl poly-
.~ siloxane silicone lubricant compositions only the phosphite
.
- -- 10 --
: , , .
~ 60SI-121
and phosphonates of the ins-tant case are needed to impart
or improve the lubricant composition such that it has
optimum antiwear properties when it is utilized to lubricate
soft or hard metals. In any case, as disclosed in the
instan-t cae, the chlorinated benzoate and the chlorinated
phthalate additives of the foregoing Agens patent may be
utilized with advantage with cer~ain linear diorganopoly~
siloxane silicone lubricant compositions as may be desired.
At any rate, such additives do not produce any harmful
effects when they are added to silicone lubricant com-
positions and are certainly advantageously added to the
linear dimethylpolysiloxane silicone lubricant compositions,
so as to optimize the antiwear properties of such polymers.
The linear diorganopolysiloxane polymers may be produced
by any method that is well known in the art. For instance,
in the case of polysiloxanes substituted by methyl and
phenyl units, polysiloxanes substituted by chlorophenyl~
tetrachlorophenyl and methyl units and polysiloxanes
substituted by methyl and trifluoropropylsiloxane units,
such polymers may be prepared by the equilibration of
the appropriate cyclotetrasiloxanes with the appropriate
amount of chain-stoppers such as, hexamethyldisiloxane,
octamethyltrisiloxane and etc. In the presence of an
~ acid catalyst such as, toluene sulfonic acid, acid activated
,, .~ ~
clay such as, Filtrol manufactured and sold by the Filtrol
of Los Angles, California, and etc. The amount of chain-
stopper in the equilibration mixture will determined the
final molecular weight of the equilibrated polymer (usually
, ~ the equilibration is stopped when ~5~ of the cyclicpoly ~ -
siloxanes has been converted to a linear polymer). At that
time the equilibration which is carried on at elevated
temperatuxes of about 100 C is simply terminated by lower-
; ~
,,
-- 11 --
. , ~. .
~ 60SI-121
ing the temperature and venting off the excess cyclic
material. In the case of the linear diorganopolysiloxane
polymer that is to be composed of methyl and trifluor-
propyl units, either the appropriate cyclictrisiloxane
or tetracyclicsiloxane may be utilized in the equilibration
reaction as is well known in the art. In any case whether
cyclictrisiloxanes or cyclicsiloxanes are utilized in the
instant case depends on the choice or skill of the worker
in the art in his experience with a particular type of
reaction. AS an example of a process for producing such
methyltrifluoropropyl cyclicsiloxanes and producing a
polymer therefrom, reference is to the U.S. Patent No.
3,937,684 dated February 10, 1976.
The methods for producing such linear diorganopoly-
siloxane polymers with various substituent groups is well
known in the art and as such will not be repeated here in
detail. Another preferred linear diorganopolysiloxane
polymer for utilization as to basic lubricant in the invention
of the instant case for soft metals with the additives of
the instant case is a linear polysiloxane polymer having
methyl and tetrachlorophenyl substituent groups. Such
polymer is, for instance, disclosed for use as a lubricant
in U.S. Patent 2,970,162 - Brown dated January 31, 1961.
Accordingly, it will TlOt be necessary to go into preparation
of such materials or disclosure. Suffice to say that
such linear diorganopolysiloxane polymer substituted by
methyl and tetrachlorophenyl substituent groups are well
known. It was the discovery of the instant case that the
utilization of the chlorinated phosphites and phosphonates
of the instant case would improve such lubricants when
they were utilized to lubricate soft metals such that the
antiwear properties of such silicone lubricants are superior
- 12 -
~ 60SI-121
to that of the priot art.
Finally, there can be utilized as a preferred lubricant
fluid in the lubricating composition of the inskant case, a
methyl higher-alkyl linear polysiloxane of a viscosity as
set forth previously. Preferably the higher-alkyl group
in such linear polysiloxane polymer has from 6 to carbon
atoms and is more preferably decyl, dodecyl and etc. Such
polysiloxane polymer is linear except that each silicone
atom has a substituent selected from methyl and also has a
substitute selected from a higher-alkyl radical where the
carbon atoms are the high-alkyl substituted groups in the
linear polysiloxane polymer varies from 25 to 50 mole
percent of the total substituent groups on the polymer.
Such higheralkyl polysiloxane polymers are generally produced
by reacting a hydrogen-containing linear polysiloxane poly-
mer, which can be produced by the foregoing equilibration
techniques set forth previously, with an olefinic 6 to
20 carbon atom organic molecules such that the olefinic
organic molecule is added on the hydrogen atom of the
polysiloxane to yield the methyl higher-alkyl substituted
linear polysiloxane which may be utilized as a preferred
lubricant in the instant case.
With respect to the production of the hydrogen poly-
siloxane, as stated previously, such hydrogen polysiloxanes
may be produced by equllibration techniques along the line
that is utilized for the methyltrifluoropropyl substituted
polysiloxanes or the dimethyl substituted polysiloxanes.
It should also be noted that such cyclictetrasiloxanes and
cyclictrisiloxanes as needed in the foregoing equilibration
processes, are easily produced by the hydrolysis of the
appropriate dichlorosilanes and specifically such silanes
as dimethyldichlorosilane, and methyltrifluoropropyldich-
- 13 -
... .
ql`1.24L 6 o s I- 121
lorosilane. By hydrolyzing such chlorosilanes in water there
, is obtained a mixture of cyclic and low molecular weight linear
polysiloxanes and the cyclic material is increased in concentraticn
and stripped off in fairly pure quantities by simply cracking the
hydrolyzate with an alkali metal hydroxide at elevated temperatures.
With respect to the fluid methyl higher-alkyl polysiloxanes,
one such preferred methyl, higher-alkyl polysiloxane -that can be
employed in the practice of the present invention can be charac-
terized as having the average unit formula,
~,. 3)n(R)m(R (CEI2)3)p(R~)qSiO(4
The sum (m+n+P+q) has a value of from 2.002 to 3.0; n has a value
of from 0.50 to 1.95; m has a value of from 0.50 to loOO; p has
a value of from O to 0.5; q has a value of ~rom O to one-fourth
; (m+n+p); R is an alkyl radical containing from six to 20 carbonatoms; e.g.; hexyl, octyl, decyl, dodecyl, tetradecyl, octadecyl
radicals; R' is a t-butyl-substituted hydroxyaryl radical and has
` the formula:
.:
Y ~ - OH
where Y is a memher selected from the class consisting of hydrogen,
monovalent hydrocarbon radicals, hydroxyaryl radicals~ hydroxy-
aryl-substituted monovalent hydrocarbon radicals, hydroxyaryl
ethers joined to the t-butyl-substituted hydroxyaryl radical
through the ethér l.inkage, hydroxyarylthioethers joined to
the t-butyl~substituted hydroxyaryl radical through the thioether
linkage and hydroxyaryl-methylene ethers jointed to -the t-butyl
- 14 -
~,
,
~ % ~ 60SI-121
substituted hydroxyaryl radical throuyh the methylene e-ther
linkage; R" is selected from the class consisting of lower
alkyl radicals having one to five carbon atoms, e.g., methyl,
ethyl, propyl, butyl, pentyl, etc. radicals; cycloalkyl
radicals having five to seven carbon atoms in the ring,
e.g., cyclopentyl, cyclohexyl, cycloheptyl, etc. radicals;
mono~nuclear and binuclear aryl radicals, e.g., phenyl,
naphthyl, diphenyl, etc. radicals; mono-nuclear aryl lower
alkyl radicals, e.g., benzyl, tolyl, xylyl, phenylethyl,
etc. radicals and halogenated derivatives of the above
radicals.
Although any methylalkylpolysiloxane fluid within the
scope of formula (1~ is applicable in the process of the
present invention, it is preferred that the fluid have a
viscosity of from about 25 centistokes to about 100,000
centistokes when measured at 25C.
The t-butyl-substituted hydroxyl aryl methyl higher-
alkyl polysiloxane polymer described above is the preferred
methyl higher-alkyl polysiloxane polymer for utilization
as a silicone lubricant. Preferably, the t-butyl-sub-
stituted hydroxyaryl radical is present in the polymer
chain so as to retard any oxidation of the lubricant fluid.
Although a methyl higher-alkyl polysi]oxane polymer may be
utilized without such a t-butylsubstituted hydroxyaryl
radical for anti-oxidation purposes in the preferred
silicone lubricants o~ the instant case, i-t is desired
to have such a substituent group in the higher-alkyl
polysiloxane lubricant composition. The preparation of the
methyl higher-alkyl polysiloxane polymers is more fully
described in ~.S. Patent No. 3,669,884 dated June 13, 1972.
Accordingly, it is not necessary to go into any detailed
process about the preparation of such fluids since if any
- 15 -
6OSI-121
more details than -that given above are needed as to the
preparation of such methyl higher-alkyl polysilo~ane
polymers with or without the t-butyl substituted hydroxyaryl
radical, reference should be made to the foregoing
Wright 3,669,884 dated June 13, 1972. As stated previously,
for such methyl, higher-alkyl polysiloxane polymers when
such polymers are utilized to lubricate either ha.rd metals
or soft metals the foregoing chlorinated benzoate and
phthalate additives of the Agens U.S. Patent 2,837,482,
dated June 3, 1958, are not needed, as long as the chlorinated
phosphites, chlorinated phosphona*e additives of the
present case are present. It should be noted at this
juncture that the foregoing chlorinated phosphites and
chlorinated phosphonates of the instant case are not
disclosed as substituent additives for the foregoing
chlorinated benzoates and chlorinated phthalates of
the foregoing Agens U.S. Patent 2~837/482 dated June 3, 1958.
The phosphites and phosphonates of the instant case improve
the antiwear and lubricating properties for soft metals
of silicone lubricants considerably more efficiently and
at a higher level than is the case when the chlorinated
benzoates and chlorinated phthalates of -the foregoing
~gens U.S. Patent No. 2,837,482 dated June 3, 1958 are
utilized.
There are also other well known silicone polymers that
may be utilized as silicone lubricant.s. Without mentioning
-~ these polymers in detail, it is suffice to state that the
instant chlorinated phosphites and chlorinated phosphonate
additives of the instant case are superior imparting anti-
`~
- 16 -
60SI-121
L2~
wear properties for soft metals to such lubricants than
has been the case when such polymers have been utilized
without any addltives or have been utilized with any of
the prior art additives. Accordingly, with any of these
silicone polymers that are utilized as lubricants, there
may be utilized from .01 to l part by weight of a chlorinated
phosphite or phosphonate. Although any chlorinated phosp-
hite or phosphonate may be utilized, the most preferred
that have been found suitable for most silicone lubricants
and more specifically for the silicone lubricants mentioned
above is tris-chloroethylphosphite and bis-chloroethyl-
chloroethylphoshonate. It should be noted that it has
been theorized that the trischloroethylphosphite changes
to a bis-chloroethyl phosphonate after the passage of
time and the two compounds are in equilibrium with each
other. It has been postulated that these two compounds
are the most effective antiwear additives for the fore-
going silicone lubricants with respect to soft metals,
such as, copper, brass or bronze. ~lthough less that .01
parts may be utilized, that is, even a slight trace of the
instant phosphites and phosphonates will impart antiwear
characteristics to a silicone lubricant, nevertheless it
is felt that .01 parts by weight of the chlorinated phosphite
or phosphonate are needed per lO0 parts by weight of the
` linear organopolysiloxane polymer for the phosphite or
phosphonate to impart to the silicone lubricant sizable
antiwear properties for soft me~als.
Further, evsn though more than one part by weight
of the chlorinated phosphite or phosphonate could be
utilized, generally such an excess amount may not be
soluble in the silicone lubricant, thus negating its
effectiveness as an antiwear additive. Preferably, 0.2. to
0.6 parts of the chlorinated phosphite or phosphonate is
- l7 -
., ,
"
, . . .
~OSI-121
utilized per 100 parts of the essentially linear organo-
polysiloxane polymer. Chlorinated phosphites and phosphon-
ates are sold by Mobil Oil Company, Monsanto Chemical
Company and Berg Warren Corp., as well as many others.
These phosphites and phosphonates are generally
produced by reacting ethylene chlorohydrin with P c13. The
phosphonates are formed spontaneously by Arbuzov rearrange-
` ment.
The above preparation for the foregoing phosphites
and phosphonates is only meant to be exemplary, such
materials being manufactured and sold by the foregoing
companies listed above. Accordingly, it is not necessary
to go into any further details as to their preparation.
Again, as stated previously, although the foregoing
chloroethyl phosphites and phosphonates are the most
preferred in the instant application, any other chlorinated
alkyl phosphites and phosphonates may be utilized as ad-
ditives in the lubricants of the instant case. In the
examples below various additives were added to different
organopolysiloxanes intended as lubricants. These mixtures
were then tested for their lubricity properties on a Shell
four-ball tester which comprises a device for holding three
rigidly clamped one-half inch metal balls in a metal cup.
A further rotating ball of the same diameter is then pressed
to contact with the three stationary balls by an adjustable
floating arm and allowed to run for 1 hour. The contact
points on the three stationary balls shows a circular scar
~ as wear progresses. The average diameter of these scars
; in millimeters after a 1 hour run at some particular speed
and load is taken as the measurement of wear. The tem-
perature at which the test is conducted may also be varied
from room temperature to elevated temperatures of the order
- 18 -
60SI-121
of about 150C. All balls are immersed in the lubricant
fluid during the test. The type of metal employed in khe
balls can be changed as, for example, lubricating surfaces
can be steel-on-steel or steel-on-brass or brass-on-steel.
In the examples below, in all tests there was a 40 kill-
ogram load on spinning ball which was made of bronze and
in which the lubricant was maintained of a temperature of
167F. The center ball in which the load was rotated for
1 hours in the test in each case at a rotation of 1200
rotations per minute. The other balls were construc-ted
at 25/100 tool steel. The sliding friction was also
measured during each test. The examples below are given
for the purpose of illustrating the reduction to practice
of the instant invention and are not given for any
purpose in limiting the definition and scope of the instant
specification and claims. All percentages and parts are
by weight.
` ~ In all of the test results tabulated below, there was
utilized as the basic lubricating fluid, a fluid identi
fied as Fluid X in the table below, which Fluid X is a
linear polysiloxane having a 50 centipoise viscosity at
25C and was a methyldecyl substituted polysiloxane polymer
' having trimethylsiloxy terminal groups which has 1 - 3%
' coupled into it of t-hydroxyphenyl units. All the per-
centages in the table are by weight of the additives
` added. The test are previously stated was carrled out in
a Shell 4-ball tester which was run with a 40 killogram
load on the rotating ball which was made of 25/100 steel
and rotated at a rotation of 1200 rotations per minute
for 1 hour while impinging on the three balls constructed
~` of bronze all of which balls were immersed in the Fluid X.
The amound of the additives added is indicated in the table
~ .
., -- 1 9
, .
- - :
60SI~121
29~
below in which the lubricant and additives mixture was
maintained at a temperature of 167F for the 1 hour length
of the test. Results of the tests are as follows:
TABLE 1
Lubricant Wear Scar SL
Fluid X 1.7 mm Rose
To 0.15
Fluid X + 4% dibutylhexyltetra-
chlorophthal-ate 0.84 mm 0.05
Fluid X ~ 0.5~ tris-chloroethyl-
phosphite 0.82 mm 0.05
Fluid X + 0.2~% tris-chloroethyl-
phosphite 0.93 mm 0.05
Fluid X + 1.0% tris-chloroethyl
phosphite 0.84 mm 0.05
'.
In addition, other conventional additives were tries.
These failed completely.
Fluid X + dialkyl zinc dithio-
phosphite 2.6 rose to 1.7
Fluid X " dibutyl tin sulfide 2.4 rose to 1.5
As noted from the results set forth in Table 1 above,
the instant phosphite and phosphonate additives were much
more effective as antiwear additives for soft metals
than were other conventional additives which failed com-
pletely and were at l/~th the concentration just as
effective as the dialkyltetrachlorophthalates as antiwear
additives for soft metals. It should be noted that the
instant phosphites and phosphonates as the above xesults
in Table 1 indicate, even in trace amounts that is at a
concentration of 0.25 weight percent in the methyl hi~her-
alkyl fluid markedly improved the antiwear properties of ~-~
- 20 -
60SI-121
said methyl higher-alkyl fluid toward soft metals as indicated
above. Accordingly, at the same concentrations the chlori-
nated phosphite and chlorinated phosphonate additives of
the instant case are the most effective additives for org-
anopolysiloxane polymers as far as optimizing the antiwear
properties of silicone lubricant polymers than is the case
with prior art phthalate and benzoate additives and other
prior art additives for this purpose.
- 21 -
.
