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Патент USA US3088941

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United States Patent O " ice
Clyde 5. Scanley, Stamford, Frederick H. Siegele, Cos
Patented May 7, 1963
polymerization and astonishingly small amounts of polar
monomers, when grafted on, impart excellent detergency.
As little as 0.05% impart useful detergence properties and
larger amounts up to 15% may be used. Still larger
amounts do not give any advantageous results and merely
increase the cost of the resulting product without bene?t.
For best practical operation, the rate of polar monomers
grafted on should be fromv 0.1% to 10%, this constituting
Cob, and Richard L. ‘Webb, Darien, Conn., assignors to
American Cyanamid Company, New York, N.Y., a
corporation of Maine
the preferred range and being included as a more speci?c
No Drawing. Filed Oct. 2'7, 1958, Ser. No. 769,595
2 Claims. (Cl. 260-455)
10 aspect of the present invention.
In order to produce oxidized sites in the acid catalyzed
This invention relates to improved polymer useable as
polymer backbone, there must be present active hydrogens.
oil additives for the improvement of viscosity index and
This may be a hydrogen attached to a carbon atom to
for other purposes where detergency is of importance.
which oxygen is attached together with other organic
There are a number of problems in connection with
radicals, as in the case of vinyl ether, or they may be
petroleum fuels and lubricants in which the use ‘of addi 15 activated in other ways, that is to say the hydrogen may
tives are important to impart improved properties. One
be a tertiary hydro-gen, the other bonds to its carbon atom
of the important classes of petroleum products are lubri
being organic radicals. A double bond also will pro
cating oils. Lubricating oils present a viscosity problem
duce an activated hydrogen as will, in some cases, the
because of the very wide range of temperatures over which
20 presence of a halogen atom. Typical tertiary hydrogen
they operate. Thus, for example, on a cold ‘day when an
compounds are to be found in polystyrene or styrene
internal combustion engine is ?rst started, the temperature
copolymers. Double bond activation is less practical as
of the oil may be far below freezing. As the motor warms
the presence of a large number of double bonds, as in
up, the temperature of the oil increases, for example, to
polybutadiene, polyisoprene and the like results in a
the boiling point of water or even in some cases higher
25 compound which is not as stable under high temperatures.
and on a very hot day or in the case of lubricants which
However, where only a few sites are needed, the polymer
are subjected to special heat problems such as the lubri
backbone may contain a corresponding number of double
cants in certain torque converters, the oil temperature
bonds to produce activated hydrogens. Hydrogens ac
may go still higher. It is important that the viscosity
tivated by the presence of halogen on the same carbon
of the lubricant be not too high so that it will flow ‘at 30
atom are also useful.
very low temperatures and yet not thin out sufficiently at
high temperatures so that inadequate lubrication results.
It will be noted that polyisobutylene does not contain
active hydrogens except for the single double bond at the
end of the molecule. In other words, a homopolymer
dewaxed, show too high a variation in viscosity with tem
of isobutylene cannot be used according to the present
perature or, as is normally stated in the art, have ‘a poor 35 invention to produce compounds with grafted polar mono
viscosity index.
mers. On the other hand, isobutylene is cheap and it
A number of additives have been used to improve vis
confers satisfactory viscosity index improvement. There
cosity index. One type comprises polymers of either iso
fore, when isobutylene backbone polymers are to be used
butylene or vinyl ether which are prepared by conven
in the present invention, they must be copolymerized with
Ordinary petroleum hydrocarbon lubricants, even when
tional acid catalyzed processes. These polymers, when 40 a sufficient number of monomers, such as vinyl ether,
of appropriate molecular weight, are in fact good viscosity
styrene and the like so as to provide an adequate number
index improvers. However, there is another property
of activated hydrogens in the molecule to produce the
which is important in lubricants, especially heavy duty
required sites for ‘grafting on of polar monomers by ‘free
lubricants, and that is detergency or the property of
radical polymerization. In general, when it is desired to
maintaining decomposition products of the lubricating oil, 45 produce a polymer with a large proportion of isobutylene,
such as tars, particles of carbon and the like, in a ?ne
dispersion so that they do not deposit in the parts ‘of an
internal combustion engine and do not cause serious
the comonomers having activated hydrogens may vary
from 0.02% up to 20%. Of course, higher amounts may
be present but inasmuch as these monomers are some
plugging of oil ?lters, particularly those of the ?ne pore
what more expensive than isobutylene and no advantage
sintered metal type. The polyisobutyleues ‘and polyvinyl 50 is obtained, the 20% constitutes an economic limit for
others have little or no detergent powers and this has made
them less satisfactory as lubricant additives.
cheapest products.
-It is an advantage of the present invention that the
initial backbone of the polymer may be produced by con
would contain a large number of polar groups, such as
ventional polymerization methods using conventional cata
polymers of methacrylic esters, maleic esters and the like. 55 lysts. Up to this point, the polymers are not new and
These polymers do have detergent properties but their cost,
no new techniques need to be learned in producing them.
which is much higher than polyisobutylene ‘or polyvinyl
It is likewise an advantage that the preparation of the
ether, is a serious disadvantage. An attempt was made
oxidized or peroxide sites for graft polymerization may
to produce eopolymers from monomers, such as vinyl
be effected by various means which are in themselves
ether and random polar monomers. Such copolymers ‘are 60 known. Thus, for example, ionizing radiation, for ex
satisfactory viscosity index improvers but have entirely
ample X-rays, high energy electrons and the like may
insui?cient detergent properties to be practically useful.
be used. Chemical preparation, for example by treat
The present invention produces polymers of predomi
ment with ozone, is another useful method. The grafting
nantly cheap, acid catalyzed monomers such as isobutyl
of the polar monomer is effected simply and easily by
ene, vinyl ether and the like. However, instead of copoly 65 heating, if desired, in a suitable solvent.
m'erizing with polar monomers, the acid catalyzed poly
Attempts have been made to produce polymers which
mer backbone is treated to form so-called oxidized sites
on which polar monomersh can be grafted by free radical
Various polar monomers can be used, such as nitro
gen bases, both tertiary and quaternary, having suitable
ole?nic double bonds.
Typical compounds are as fol
produce oxidized sites, there are some practical limits.
Thus, the e?iciency of the radiation from X-rays from
electron beams of too low voltage is insu?icient to be
Diallyl dialkyl ammonium halides
useful. The practical limit may be considered X-rays
Dialkylaminoalkyl acrylates and methacrylates
from beams having from ?fty thousand to ten million
Dialkylaminoalkyl vinyl ethers and quaternary vinyl ethers
electron volts, preferably from half a million to ten mil
Alkyl vinyl sulfoxides and sulfones
lion. Of course, higher energy beams may be used to
Dialkylaminostyrenes and methylstyrenes
produce harder X-rays but there is no advantage and the
N-substituted acrylamides
cost of equipment rises very rapidly. The dose varies
10 between 0.1 and 10 megarads, preferably from 0.75 to
2.5 megarads. The lower limit is set by that at which
Bis-(Z-dialkylaminoalkyl) fumarates
a minimum amount of grafting is made possible and is
N-vinyl carbazole
Vinyl pyridines
2-(4-morpholinyl) ethyl acrylate
2-morpholinylethyl vinyl ether
Piperazinylethyl vinyl ether
1-(,6-methacrylyloxyethyl) piperidine
Vinyl pjurolidone
Another form of polar monomer are acidic monomers,
such as acrylic acid, methacrylic acid, vinyl sulfonic acid
and the like. The acids, of course may be present either
as free acids or salts.
It is not known why so small a quantity of polar mono
mers, when grafted on according to the present inven-~
in general lower than preferred most practical operations,
although such small doses can be used.
The upper limit
15 is determined by the effect on the molecular weight.
Substantial diminishing of molecular weight occurs at
a dosage of 10 megarads and rises rapidly with increas
ing doses. This may therefore be considered as the prac
tical top limit for dosage.
The invention has been described particularly in con
nection with polymers to be used ‘as additives for lubricat
ing oil in ‘order to improve both the viscosity index and
detergency. Another use in which the detergent effect
is the primary function lies in jet fuels and similar fuels
which have to pass through a ?ne ?lter, such as a sintered
bronze or steel ?lter. It is essential to prevent larger
particles from entering a jet engine. However, dif?culty
tion, confer'such a relatively enormous increase in de
is sometimes encountered due to plugging of the ?ne pores
tergent power. It is not desired, therefore, to limit the
of the ?lter with carbon tars or other decomposition
invention to any particular theory and especially it is
products of the fuel for the latter is usually used as a
not desired to limit it to any speci?c proportion of the
coolant on its way to the combustion chamber and so is
total number of oxidized sites on which free radical
subjected to fairly high temperatures which can result
polymerization takes place. In other words, a given
in some decomposition. A small amount of the index
number of polar monomers may be grafted singly each
improving polymers of the present invention will provide
to one site or a number of them may be grafted in the 35 for a satisfactory detergency which prevents or mini
form of a chain on a fewer number of sites. Without
mizes difficulties resulting from ?lter clogging. Other
desiring to limit the invention, it is believed that a possi
uses in which the detergency is the primary factor include
ble explanation of the greatly increased detergent power
dispersions such as printing inks.
may be that the grafted polar monomers are sticking out
When used to impart improved detergency or disper
as chains from a predominantly straight chain polymer
sion to jet fuels and other systems such as printing inks,
backbone and so have more active groups than if they
the amount of the copolymer used will often be much
less than in a lubricating oil and it may be used in
likely, though by no means certain, that on at least some
amounts such that there is no marked change in viscosity
sites, more than one polar monomer may be involved in 45 index. The polymer, however, still has the same proper
the graft.
ties of improving the viscosity index of oils when used
in suitable amounts.
It has been pointed out above that the formation of
oxidized sites for free radical polymerization may be ef
Reference has been made above to the desirability, in
fected by ionizing radiation. In general, this procedure
some cases, of using a solvent in a radiation step which
should be used with solvents as it is necessary to the in 50 can later be used for the free radical grafting. It is not
vention that the polymer be in the form of a liquid. The
necessary that the reaction proceed in completely separate
radiation of solid polymers and subsequent grafting does
steps, although for some purposes this is desirable and
not produce useable products under the present inven
permits maximum control of the reaction. It is also
possible to operate in a one step process which saves
tion. While it is desirable to use a solvent, the par
ticular solvent to be used is not critical. Typical sol 55 several steps and is also included in the invention. It
should therefore be understood that while in fact there
vents are the following: acetone, bromoform, carbon
are two steps in the reaction mechanism, these steps may
tetrachloride, chlorobenzene, chloroform, cyclohexane,
were part of the backbone itself. It is also thought
be going on simultaneously in a single operative step.
Reference has been made to the desirability of produc
60 ing a liquid polymer. For many purposes, this is very
satisfactory. However, it should be understood that since
the polymer is used in solution in hydrocarbon lubricating
chloride, octane and propanol. It is also possible to use
oils or fuels, it is not necessary that the pure polymer be
water, although this is not a solvent, provided the acid
itself liquid. It is su?icient that it is oil soluble and forms
catalyzed backbone polymer in the form of a liquid or
a suitable solution in the hydrocarbon in which it is
a solution is emulsi?ed or otherwise ?nely dispersed
?nally used.
The invention will be described in greater detail in con
For the most part, the solvents may be used in the
junction with the speci?c examples in which the parts
subsequent step which has the advantage of utilizing
are by weight unless otherwise speci?ed. The examples
the same reaction medium for two steps and so saving
costs of isolation. However, some solvents, such as bro 70 are typical of procedures which result in forming oxi
dized sites and do not in this respect differ greatly from
moform and carbon tetrachloride which are useable in
what is known of the means for accomplishing this re
the irradiation step, are unsatisfactory in the grafting step
sult, such as ionizing radiation, ozone and the like. Modi
as they interfere with satisfactory growth of the branches.
?cations of the procedure as is known may be used and
While it is an advantage that ordinary radiation tech
it is an advantage that the procedure is not critical so long
cyclohexyl chloride, o-dichlorobenzene, l,2-dichloroeth
ane, diethyl ether, dioxane, ethanol, ethyl acetate, ethyl
bromide, heptane, hexane, mixed long chain aliphatic
hydrocarbons, methanol, methyl acetate, methylene di
niques may be employed when this method is used to 75 as the rather broad limits set out above are observed.
parts of pentane atv 0° C. for 2 hours. The pentane is
then evaporated off under a vacuum and replaced with
An oxygen saturated solution containing 20 parts of
an oil soluble polyvinylether copolymer in 80 parts of
80 parts of chlorobenzene and 2 parts of 2-methyl-5-vinyl
pyridine is added. The solution is deoxygenated with
chlorobenzene is irradiated with X-rays from a 250,000
volt electron beam. The irradiation is continued until
nitrogen and heated rapidly, 132° C. The heating is con
tinued for an hour and a half followed by cooling, pre
the total dosage reaches 1 megarad.
The reaction medium is deoxygenated, introduced into
cipitation with methanol and drying. Grafted polymer
analyzed 0.8% 2-methyl-5-vinyl pyridine and had deter
gent properties indistinguishable from a similar grafted
a polymerization reactor and maintained under an at
mosphere of carbon dioxide. One part of diethylami'no
ethyl acrylate dissolved in chlorobenzene is added and the
solution heated rapidly to the reflux temperature, 132° C.
polymer in which the sites were prepared by radiation
perature until grafting is complete. The reaction is then
cooled and the product precipitated with methanol and
to react at minus 40° C. until copolymerization to an oil
dried. It is an oil soluble, tacky, resinous, brown colored
?ed by precipitation with methanol and treated as de
scribed in Example 1 except that instead of using diethyl
20 aminoethyl acrylate, a corresponding amount of diethyl
aminoethyl methacrylate is used. The polymer is re
as described in Example 1.
After one half hour, an additional part of diethyla-mino
pentane, 20% isobu-tylene and 5%
ethyl acrylate was gradually added over a half'hour
period. The solution is then maintained at the re?ux tem 15 vinylisobutyl ether together with 0.5% AlClg is permitted
polymer. Analysis shows that the grafted polymer con
tained 0.63% diethylaminoethyl acrylate.
soluble ‘copolymer results. The copolymer is then puri
covered and analyzes 0.6% diethylaminoethyl meth
The procedure of Example 1 is repeated substituting for
the diethylaminoethyl acrylate ‘an equal amount of di
methylaminopropyl acrylarnide. The original polyvinyl
ether which is colorless is transformed into a resinous,
brown colored, oil soluble polymer which on analysis
product analyzes 0.25% diethylaminoethyl methacrylate.
shows 0.49% grafted dimethylaminopropyl acrylamide.
The procedure of Example 1 is repeated replacing the
The process of Example 10 is repeated replacing the
vinylisobutyl ether with an equal weight of styrene. The
diethylaminoethyl acrylate with acrylamidostearic acid
dissolved in chlorobenzene. The time for the various steps
is reduced to approximately one half. The product ob
The following dispersancy test to measure quantita
tively detergent powers of products of the preceding ex
amples is carried out as ‘follows.
0.2 part of a 20% car
bon black suspension in Fractol A (re?ned white mineral
oil) is suspended in 50 parts of kerosene. The carbon
tained analyzes 2.3% acrylamidostearic acid.
35 black is thoroughly dispersed by stirring ‘and then blend
ing in a Waring Blender. After ‘blending for one minute,
the suspension is centrifuged for 5 minutes at 3000 r.p.m.
The procedure of Example 1 is repeated replacing the
The turbidity after centrifuging is obtained ‘by measuring
diethylaminoethyl acrylate with 2-methyl-5-vinyl pyridine
but twice as much of the methyl vinyl pyridine is used and 40 transmission of the suspension with a ?lter photometer. V
A series of test dispersions were made with small addi
the reaction temperature is maintained at about 90° C.
tions, from 0.1 to 5.0 parts of a 1% solution of the
instead of 132° C. An oil soluble, tacky, resinous, brown
polymers. The test was made to determine what amount
colored polymer is obtained which analyzes 0.16% 2
percent of real polymer will give a 10% transmission‘
methyl-S-vinyl pyridine.
This is a measure of the activity of the polymer
45 as a detergent. The more active it is, the smaller the
quantity required to produce a 10% transmission read
The procedure of Example 4 is repeated replacing the
ing. The results are shown in the ‘following table:
2-methyl-5-vinyl pyridine with an equal amount of acryl
onitrile. The polymer obtained is resinous and honey
Table I
co-lored and analyzes 0.4% acrylonitrile.
The procedure of Example 1 is repeated replacing the
diethylaminoethyl acrylate with an equal amount of N
in Poly- T. reading in
the Dispers
ancy Test
__________________________ __ Not active
ether copolymer.
Do _________ __
Do _________ __
hours at room temperature with X-rays as described in
Do _________ __ N‘vinyl pyrroli-
Example 1. The total dosage is slightly over 1 megarad.
Wt. Percent
of Polymer
soluble polyvinyl ether and 2 parts of Z-methyl-S-vinyl
pyridine in 80 parts of chlorobenzene is irradiated for 2 60
The grafted polymer is reprecipitated with methanol
Nitrogen givinga10% Viscosity
vinyl pyrrolidone. The product ‘obtained is resinous and
brown colored and analyzed 0.56% N-vinyl pyrrolidone. 55
isobutylEXAMPLE 7
ethyl hexyl vinyl
An oxygen free solution containing 20 parts of an oil
propyl acrylamide.
ethyl acrylate.
Do _________ __
several times from pentane and dried. The product
D0 _________ __ 2-methyl-5-vinyl
showed good detergency by the detergent test which fol 65
lows the examples.
The procedure of Example 7 is repeated replacing the
The irradiation and grafting of the polyvinylether co
2-methyl-5evinyl pyridine with an equal amount of N 70 polymer was carried out as described in Example 4.
Do _________ __
vinyl pyrrolidone. The product obtained is oil soluble
and shows good detergent powers.
Ozone is bubbled through -a solution containing 20 75
parts of an oil soluble polyvinylether copolymer in 80
In this case the monomer grafted was acrylic acid.
grafted polymer contains 0.25% acrylic acid.
The ozonolysis and grafting of the polyvinylether was
carried out as described in Example 9. The grafted
monomer was acrylic acid. This grafter polymer con
tains .52% acrylic acid.
A polyvinylether grafted with 1.0% diethyl-arninoethyl
metha-crylate was added at a concentration of 0.03% to
a jet ‘engine fuel. The additive containing jet fuel was
0.05% to 15% of an unsaturated, polar, nitrogen-con
taining monomer based on the weight of the said polymer
and having a detergent power such that less than 0.15%
.p by weight of the polymer in an 0.08% by weight carbon
black suspension in kerosene which is then centrifuged
heated and recirculated through a ?lter under pressure.
Fuel stability is determined by operating until a pressure 10
drop of 25 inches of mercury is obtained ‘across the ?lter
or until 300 minutes have elapsed. A fuel containing
no additive failed after 130 minutes. The fuel contain
ing the additive described above exhibited only an 0.2
inch pressure drop during the 300 minute duration of the 15
We claim:
1. A graft polymer having viscosity index improving
butylene, said polymerv having grafted thereon from
imparts 10% transmission of visible light.
2. A copolymer according to claim 1 in which the
range of polar monomer is'from 0.1% to 10%.
References Cited in the ?le of this patent
Giam-m-aria __________ __' Dec. 20, 1955
Catlin _______________ __ Mar. 6, 1956
Vandenberg __________ .._ June 3, 1958
Banes et al. -I. _________ __ June 110,.1958
Coover et a1. _________ __ Apr. 14, 1959
properties and detergent properties consisting of a co-.
polymer of isobutylene with from 0.2% to 20% of a
monovinyl ether monomer having an active hydrogen 20.
capable of transformation into an oxidized site said per
centage of the monovinyl monomer being based on is0-_
Barney __________ _______,_ July 7, 1959
France ______________ __ Mar. 31, 1953
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