U.S. patent application number 11/594618 was filed with the patent office on 2007-05-24 for acrylic synthetic lubricant.
Invention is credited to Shih-Ying Hsu, Willie Lau, Miao-Hsun Li Sheng.
Application Number | 20070117725 11/594618 |
Document ID | / |
Family ID | 37890219 |
Filed Date | 2007-05-24 |
United States Patent
Application |
20070117725 |
Kind Code |
A1 |
Hsu; Shih-Ying ; et
al. |
May 24, 2007 |
Acrylic synthetic lubricant
Abstract
A synthetic lubricant comprising a relatively
low-molecular-weight acrylic polymer.
Inventors: |
Hsu; Shih-Ying; (Chalfont,
PA) ; Lau; Willie; (Lower Gwynedd, PA) ;
Sheng; Miao-Hsun Li; (Lower Gwynedd, PA) |
Correspondence
Address: |
ROHM AND HAAS COMPANY;PATENT DEPARTMENT
100 INDEPENDENCE MALL WEST
PHILADELPHIA
PA
19106-2399
US
|
Family ID: |
37890219 |
Appl. No.: |
11/594618 |
Filed: |
November 8, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60739985 |
Nov 22, 2005 |
|
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Current U.S.
Class: |
508/471 ;
508/469; 508/472 |
Current CPC
Class: |
C10M 2205/04 20130101;
C10N 2030/14 20130101; C10M 2221/0405 20130101; C10M 107/28
20130101; C08F 220/18 20130101; C10M 2209/084 20130101; C10M
2221/02 20130101; C10N 2020/02 20130101; C10N 2030/12 20130101;
C10N 2030/08 20130101; C10M 107/42 20130101; C10M 2217/024
20130101; C10M 107/46 20130101; C10N 2020/04 20130101; C10N 2020/01
20200501; C08F 220/1812 20200201; C10M 145/14 20130101; C10M
2209/0845 20130101; C10M 2217/0245 20130101; C08F 220/18 20130101;
C08F 2/38 20130101 |
Class at
Publication: |
508/471 ;
508/469; 508/472 |
International
Class: |
C10M 145/14 20060101
C10M145/14 |
Claims
1. A synthetic lubricant comprising an acrylic polymer having: (a)
M.sub.n at least 1,000 and no more than 20,000; (b) residues of at
least one alkyl(meth)acrylate monomer having a C.sub.2-C.sub.22
alkyl group; and (c) a terminal reactive group derived from a
radical chain transfer agent.
2. The lubricant of claim 1 in which said at least one alkyl
(meth)acrylate monomer has a C.sub.4-C.sub.22 alkyl group.
3. The lubricant of claim 1 in which the acrylic polymer has a
T.sub.g no greater than 40.degree. C.
4. The lubricant of claim 1 in which the terminal reactive group is
a hydroxy or thiol group.
5. The lubricant of claim 1 in which the acrylic polymer has a
total of no more than 50% residues derived from among styrene
monomers, methacrylamide, methacrylamide monomers, methacrylate
monomers, and methacrylic acid.
6. The lubricant of claim 1 in which the acrylic polymer is
substantially free of carboxylic acid groups and amino groups.
7. The lubricant of claim 1 in which the acrylic polymer has
M.sub.n at least 2000 and no more than 10,000.
8. The lubricant of claim 1 in which the acrylic polymer has at
least 50% of residues derived from C.sub.4-C.sub.22
alkyl(meth)acrylates.
9. The lubricant of claim 1 in which the acrylic polymer has at
least 20% of residues derived from C.sub.8-C.sub.22 alkyl
acrylates.
Description
[0001] This application claims the benefit of priority under 35
U.S.C. .sctn. 119(e) of U.S. Provisional Patent Application No.
60/739,985, filed on Nov. 22, 2005, the disclosure of which is
incorporated herein by reference.
[0002] This invention relates to a synthetic lubricant comprising a
synthetic acrylic polymer.
[0003] Synthetic lubricants of various types are commonly used in
the petroleum industry to provide high performance beyond the reach
of lubricants based on mineral oils. Polyolefins, alkylaromatics
and polyol esters are typical examples of materials that have been
used for this purpose. For example, U.S. Pat. No. 5,691,284
discloses copolymers of 1-alkenes and (meth)acrylic acid esters.
However, such copolymers can be difficult to produce, and this
reference provides no guidance as to which acrylic polymers might
have desirable properties as synthetic lubricants.
[0004] The problem addressed by the present invention is the need
for improved synthetic lubricants.
STATEMENT OF INVENTION
[0005] The present invention provides a synthetic lubricant
comprising an acrylic polymer having: (a) M.sub.n at least 1,000
and no more than 20,000; (b) residues of at least one
alkyl(meth)acrylate monomer having a C.sub.2-C.sub.22 alkyl group;
and (c) a terminal reactive group derived from a radical
chain-transfer agent.
DETAILED DESCRIPTION
[0006] Percentages are weight percentages and temperatures are in
.degree. C., unless specified otherwise.
[0007] As used herein the term "(meth)acrylic" refers to acrylic or
methacrylic, and "(meth)acrylate" refers to acrylate or
methacrylate. "Acrylic monomers" include acrylic acid (AA),
methacrylic acid (MAA), esters of AA and MAA, acrylamide (AM),
methacrylamide (MAM), and derivatives of AM and MAM. Esters of AA
and MAA include, but are not limited to, alkyl and hydroxyalkyl
esters, e.g., methyl methacrylate (MMA), ethyl methacrylate (EMA),
butyl methacrylate (BMA), hydroxyethyl methacrylate (HEMA),
hydroxyethyl acrylate (HEA), isobornyl methacrylate (IBOMA), methyl
acrylate (MA), ethyl acrylate (EA), butyl acrylate (BA), and longer
chain alkyl(meth)acrylates such as ethylhexyl acrylate (EHA),
lauryl acrylate (LA), lauryl methacrylate (LMA), cetyl methacrylate
(CEMA), and stearyl methacrylate (SMA). The term "(meth)acrylamide"
refers to acrylamide (AM) or methacrylamide (MAM). Derivatives of
(meth)acrylamide include, but are not limited to, alkyl-substituted
(meth)acrylamides, e.g., N,N-dimethyl acrylamide, N,N-dipropyl
acrylamide, t-butyl acrylamide, N-octyl acrylamide, and longer
chain alkyl (meth)acrylamides such as N-lauryl methacrylamide,
N-stearyl methacrylamide.
[0008] The term "acrylic polymers" refers to polymers of acrylic
monomers, and copolymers comprising at least 50% of acrylic
monomers and (meth)acrylamide monomers. Preferably, acrylic
polymers have at least 75% of monomer residues derived from
(meth)acrylic acid or (meth)acrylate or (meth)acrylamide monomers,
more preferably at least 85%, and most preferably at least 95%.
Preferably, the remaining monomer units are derived from styrene
monomers, e.g., styrene or .alpha.-methylstyrene. Preferably,
acrylic polymers are substantially free of residues of aliphatic
olefin monomers. Preferably, acrylic polymers are substantially
free of residues of monomers other than acrylic monomers and
styrene.
[0009] An "alkyl" group is a substituted or unsubstituted
hydrocarbyl group having from one to twenty-two carbon atoms in a
linear, branched or cyclic arrangement. Alkyl groups optionally
have one or more double or triple bonds. Substitution on alkyl
groups of one or more halo, trialkylsilyl, hydroxy, alkoxy,
nitrogen-containing (e.g., amino substituted by up to two alkyl
groups), phosphorus-containing (e.g., phosphonate, phosphite or
phosphate) groups is permitted; alkoxy or trialkylsilyl groups may
in turn be substituted by one or more halo substituents.
Preferably, alkyl groups have no alkoxy or halo substituents other
than fluoro substituents, and most preferably, alkyl groups are
saturated and unsubstituted. Preferably, alkyl groups are straight
or branched chain aliphatic alkyl groups. It is understood that the
alkyl groups may be either of synthetic or of natural origin and,
in the latter case particularly, may contain a range of chain
lengths. For example, naturally sourced stearic acid, even of
commercially pure quality may contain only about 90% of stearic
chains, up to about 7% of palmitic chains and a proportion of other
chains and lower quality products may contain substantially less
stearic acid. It is intended herein that reference to the chain
length of such groups is to the predominant chain length which is
present as more than 50%, preferably in more than 75%, of the
chains. When an alkyl group is substituted, the resultant acrylic
polymer can be used as an additive, preferably in petroleum
products. For example, up to 20% of the polymer can be added to a
lubricant or fuel as a fire retardant, carrier fluid for gasoline
and diesel detergents, lubricity additive, antiwear/EP additive,
plasticizer, compatibilizer, etc.
[0010] In one embodiment of the invention, the acrylic polymer has
a T.sub.g no greater than 40.degree. C., alternatively no greater
than 30.degree. C., alternatively no greater than 20.degree. C.,
alternatively no greater than 0.degree. C., alternatively no
greater than -20.degree. C., alternatively no greater than
-40.degree. C.; preferably, the acrylic polymer has a T.sub.g at
least -100.degree. C. In one embodiment of the invention, the
acrylic polymer has a total of no more than 50% residues derived
from among styrene monomers, methacrylamide, methacrylamide
monomers, alkyl methacrylate monomers, and methacrylic acid,
alternatively no more than 30%, alternatively no more than 20%. In
one embodiment of the invention, the acrylic polymer is
substantially free of methacrylamide and methacrylamide monomers.
In one embodiment of the invention, the acrylic polymer is
substantially free of residues derived from styrene monomers,
methacrylamide, methacrylamide monomers, methacrylate monomers, and
methacrylic acid.
[0011] In one embodiment of the invention, the acrylic polymer has
less than 5% of monomer residues containing carboxylic acid groups
or amino groups, alternatively less than 2%, alternatively less
than 1%, alternatively less than 0.5%. Carboxylic acid groups would
be present on, for example, acrylic acid residues and methacrylic
acid residues.
[0012] In one embodiment of the invention, the acrylic polymer has
residues of at least one alkyl(meth)acrylate having a
C.sub.4-C.sub.22 alkyl group. In another embodiment of the
invention, the acrylic polymer has at least 50% of residues derived
from C.sub.4-C.sub.22 alkyl(meth)acrylates, or alternatively from
C.sub.4-C.sub.22 alkyl acrylates. In this embodiment, the acrylic
polymer also may contain residues of C.sub.1-C.sub.3 alkyl
acrylates, as well as residues of other monomers described herein.
In one embodiment, the acrylic polymer has at least 75% of residues
derived from C.sub.4-C.sub.22 alkyl(meth)acrylates, preferably
C.sub.4-C.sub.22 alkyl acrylates. In one embodiment of the
invention, the acrylic polymer has at least 20% of residues derived
from C.sub.8-C.sub.22 alkyl(meth)acrylates, alternatively at least
30%; preferably the C.sub.8-C.sub.22 alkyl(meth)acrylates are
C.sub.8-C.sub.22 alkyl acrylates.
[0013] In one embodiment of the invention, the acrylic polymer has
M.sub.n at least 1,500, alternatively at least 2,000, alternatively
at least 3,000; preferably the acrylic polymer has M.sub.n no more
than 10,000, alternatively no more than 8,000, alternatively no
more than 7,000, alternatively no more than 6,000.
[0014] A terminal "reactive" group is one which can react with
isocyanates, diisocyanates, nucleophilic reagents (e.g., amines,
alcohols and thiols) or Mannich reagents. In one embodiment of the
invention, a terminal haloalkyl group on the acrylic polymer has
been functionalized with an amine, alcohol or thiol, preferably one
containing a C.sub.2-C.sub.20 alkyl group. In one embodiment of the
invention, a terminal hydroxy, thiol or alkyl sulfide group on the
acrylic polymer has been functionalized with a hydroxy- or
sulfide-reactive reagent to form a terminal functional group.
Reagents suitable for such functionalization include, but are not
limited to, isocyanates, diisocyanates, Mannich reagents, including
formaldehyde/amine and formaldehyde/alcohol. Isocyanates and
diisocyanates may be aliphatic or aromatic, and will result in a
terminal alkyl or aryl carbamate or thiocarbamate group. In the
case of diisocyanates, terminal hydroxy or thiol groups from at
least two acrylic polymer chains could react with the diisocyanate,
causing the chains to be linked together.
[0015] The acrylic polymer is produced in a solvent or emulsion
process, using a radical chain transfer agent RXH, wherein X is O
or S, and R is C.sub.2-C.sub.20 alkyl; or a radical chain transfer
agent which is a C.sub.1-C.sub.3 perhaloalkane, preferably a
perchloroalkane. Preferred chain transfer agents include, e.g.,
n-dodecyl mercaptan (nDDM), CCl.sub.4 and isopropanol.
Polymerization temperatures can range from 25.degree. C. to
200.degree. C., although the preferred range is from 25.degree. C.
to 150.degree. C.
[0016] This invention also includes a method for recovering
monomers from the acrylic polymer after use, typically by heating
the acrylic polymer to 400-600.degree. C. to induce
depolymerization, depending on the nature and composition of the
acrylic polymer, followed by condensing and recovering the acrylic
monomers. Addition of hydrogen peroxide also can induce
depolymerization when the terminal group is hydroxy, thiol or alkyl
sulfide. Known processes for depolymerization of acrylic monomers
are suitable for recovering monomers from the acrylic polymer of
this invention. For example, such processes are disclosed in U.S.
Pat. No. 6,469,203 and PCT Application No. WO 2004/106277.
EXAMPLES
[0017] List of Polymers TABLE-US-00001 Entry Polymer Composition 1
70 BA/30 LA//20 nDDM 2A 100 BA//10 nDDM 2B 100 BA//5.5 nDDM 2C 100
BA//3.36 nDDM 3A 100 BA 3B 100 BA Note: monomer percentages are
calculated exclusive of chain transfer agents, which are listed
after the symbol "//" and calculated as a percentage of total
monomer amount before the symbol.
[0018] TABLE-US-00002 TABLE 1 ABBREVIATIONS INTRODUCED IN THE
EXAMPLES Surfactant Ethoxylated C6 to C18 alkyl ether sulfate
having from 1 to 40 ethylene oxide groups per molecule (30% active
in water) Vazo .TM.-67 2,2'-azobis(methylbutyrononitrile) Trigonox
.TM. 125-C75 t-Amyl peroxypivalate, 75% in mineral spirits
Me-.beta.-CD Methyl-.beta.-Cyclodextrin (BETA W7 M1.8), Wacker
Chemicals (USA), Inc., (50.8% active in water)
Example 1
Acrylic Oil by Emulsion Polymerization
[0019] The emulsion polymerizations in this example were carried
out in a 5-liter round bottom flask with four necks equipped with a
mechanical stirrer, temperature control device, condenser, monomer
and initiator feed lines and a nitrogen inlet.
[0020] Deionized water (1100 g), Methyl-.beta.-cyclodextrin (59.2
g) and surfactant (18.8) were introduced into the reaction flask at
room to form a reaction mixture. The contents were heated to
85.degree. C. while stirring under nitrogen sweep. A monomer
emulsion of deionized water (625 g), surfactant (14.1 g), monomers
BA (1050 g, LA (450 g), nDDM (300 g) was prepared separately.
[0021] At 85.degree. C., 5.0 grams of ammonium persulfate in 25
grams of water were added to the reaction mixture. An acrylic
dispersion (137.6 g at 45% solids) was added as a seed polymer.
After the temperature stabilized at 85.degree. C., the monomer
emulsion was fed into the reaction mixture over 100 minutes
together with an ammonium persulfate solution (1.0 gram in 100
grams of water). At the end of the monomer emulsion feed, the
reaction mixture was held at 85.degree. C. for 20 minutes, cooled
to 75.degree. C., chased with t-butyl hydroperoxide and isoascorbic
acid (0.51 g in 10 g of water and 0.27 g in 25 g of water,
respectively) in the presence of Fe.sub.2SO.sub.4 (4 g of 0.15%
solution). An addition chase was carried out at 60.degree. C.
[0022] The acrylic oil was isolated from the dispersion upon
evaporation of the water. The slightly hazy oil was filtered
through zeolite to obtain a clear oil.
Example 2A, 2B, 2C
Acrylic Oil by Solution Polymerization in Toluene
[0023] The solution polymerizations in this example were carried
out in a 3-liter round bottom flask with four necks equipped with a
mechanical stirrer, temperature control device, condenser, monomer
and initiator feed lines and a nitrogen inlet.
[0024] Toluene (400 g) was introduced into the reaction flask at
room temperature. The content was heated to 120.degree. C. under
nitrogen sweep. A monomer mixture was prepared containing 1000 g of
BA and nDDM (100 g, 55 g and 33.6 g for 2A, 2B and 2C respectively)
at room temperature. 73.5 g of the monomer mixture was charged into
the reaction flask, followed by an initiation solution containing
1.64 g of Vazo.TM.-67 in 10.5 g of toluene. After a 5 minutes hold,
the rest of the monomer mixture was fed into the reaction flask
over 120 minutes together with an initiator solution containing
10.45 g of Vazo.TM.-67 in 66.8 g of toluene.
[0025] The reaction temperature was held at 120.degree. C. for 30
minutes after the feed was completed followed by an initiation
solution containing 9.8 g of Vazo-67 in 62.6 g of toluene fed over
60 minutes. The temperature was held at 120.degree. C. for an
additional 30 minutes, cooled to 90.degree. C. and held for 60
minutes before cooling to room temperature. The acrylic oils
(Example 2A, 2B and 2C) were isolated by stripping toluene using a
rotary evaporator to yield clear viscous oils.
Example 3B
Acrylic Oil by Solution Polymerization in Isopropanol
[0026] The solution polymerizations in this example were carried
out in a 3-liter round bottom flask with four necks equipped with a
mechanical stirrer, temperature control device, condenser, monomer
and initiator feed lines and a nitrogen inlet.
[0027] Isopropanol (120 g) was introduced into the reaction flask
at room temperature. The contents were heated to 82.degree. C.
under nitrogen sweep. A monomer mixture containing BA (360 g), and
isopropanol (20 g) was prepared separately. The monomer mixture was
fed into the reaction flask over 120 minutes together with an
initiator solution containing Trigonox.TM. 125-C75 (14.4 g) in
isopropanol (60 g). The reaction mixture was held at 85.degree. C.
for 30 minutes at the end of the feed and an initiator solution
containing Trigonox.TM. 125-C75 (3.6 g) in isopropanol (20 g) was
added. After 30 minutes at 85.degree. C., another initiator
solution containing Trigonox.TM. 125-C75 (3.6 g) in isopropanol (20
g) was added. The reaction mixture was held at 85.degree. C. for 90
minutes and then cooled to room temperature.
[0028] The acrylic oil was isolated by stripping the isopropanol
using a rotary evaporator to yield clear viscous oil.
Example 4
Characterization of Acrylic Oils
[0029] Glass transition temperature (Tg) was measured by
Differential Scanning Calorimetry (Model 12920, TA Company).
Molecular weights were determined by Size Exclusion Chromatography
using a polystyrene standard from Polymer Laboratories (PS-1)
having a peak average molecular weight ranging from 580 to
7,500,000 with narrow molecular weight distribution. Conversions
from polystyrene to PMMA were made using Mark-Houwink constants.
TABLE-US-00003 Examples Tg (.degree. C.) Mw Mn 1 -52.2 2449 1842 2A
-66.6 4005 2775 2B -59.2 5710 3811 2C -53.3 9425 6007 3A -53.1 9368
6106 3B -53.6 4616 3292
[0030] TABLE-US-00004 Test Results for Acrylic Synthetic Lubricants
Viscosity.sup.1 Viscosity.sup.1 Pour Flash OH value.sup.5, Copper @
40.degree. C., @ 100.degree. C., Viscosity point.sup.3,
point.sup.4, .degree. C., Mg corrosion.sup.6, Sample cSt cSt
index.sup.2 .degree. C. COC KOH/g 100.degree. C./3 h 1 117 16.8 156
-- -- -- -- 2A 417 44 161 -30 246 NA 1b Max 2B 1046 92 175 -24 213
NA 1b Max 2C 2810 191 185 -15 282 NA 1b Max 3A 3570 220 183 -9 207
3.7 NA 3B 1152 84 151 -21 154 14.1 NA .sup.1According to ASTM D-445
.sup.2According to ASTM D-2270 .sup.3According to ASTM D-97
.sup.4According to ASTM D-92 .sup.5According to ASTM D-1957
.sup.6According to ASTM D-130
* * * * *