Claims
- 1. The process for preparing a graft polymer which comprises
- intimately mixing in a reaction mixture
- (a) an oil-soluble, substantially linear, carbon-carbon backbone polymer of molecular weight M.sub.n of 10,000-1,000,000;
- (b) as a first graft monomer amine containing a polymerizable ethylenically unsaturated double bond, (i) N-vinylpyrrolidone, (ii) N-vinylimidazole, (iii) the reaction product of an amine and an epoxy of an aliphatic unsaturated carbocyclic acid, (iv) the reaction product of an amine and an ether containing an epoxy group and an ethylenically unsaturated carbon-to-carbon double bond, or (v) the reaction product of an amine and an aldehyde containing a carbon-to-carbon double bond;
- (c) as a second functional monomer, a phenothiazine; and
- (d) a free radial initiator;
- maintaining the temperature of the reaction mixture at a temperature at least as high as the decomposition temperature of said initiator thereby effecting decomposition of said initiator and bonding of said first and second monomers onto said backbone polymer to form graft polymer; and
- recovering said graft polymer.
- 2. The process for preparing a graft polymer which comprises
- intimately admixing in a reaction mixture (i) an oil-soluble, substantially linear, carbon-carbon backbone polymer, (ii) first graft monomer amine containing a polymerizable ethylenically unsaturated double bond and (iii) a free radical initiator,
- maintaining the temperature of the reaction mixture at a temperature at least as high as the decomposition temperature of said initiator thereby effecting decomposition of said initiator and binding of said graft monomer onto said backbone polymer to form graft polymer;
- intimately admixing in a reaction mixture (i) said graft polymer and (iii) as a second functional monomer, a phenothiazine and (iii) a free radical initiator;
- maintaining the temperature of the reaction mixture at a temperature at least as high as said decomposition temperature thereby effecting decomposition of said initiator and bonding said second functional monomer onto said graft polymer to form product graft polymer; and
- recovering said product graft polymer.
FIELD OF THE INVENTION
This is a division of application Ser. No. 06/726/567, filed Apr. 24, 1985, now U.S. Pat. No. 4,820,776.
This invention relates to hydrocarbons including hydrocarbon fuel oils and lubricating oil. More particularly, it relates to hydrocarbons which contain graft polymers which permit attainment of improved properties.
As is well known to those skilled in the art, hydrocarbon fuels and lubricating oils must be formulated, as by addition of various additives, to improve their properties.
In the case of hydrocarbon fuels, typified by fuels boiling in the gasoline boiling range, kerosene, middle distillate fuels, home heating oils etc., it is found that after extended periods of storage, they are characterized by undesirable characteristics typified by formation of solid deposits within the system.
In the case of lubricating oils, typified by those employed in railway, automotive, aircraft, marine etc. service, it is found that they become degraded during use due inter alia to formation of sludge which may be generated by deterioration of the oil or by introduction of undesirable components from other sources including the fuel or the combustion air. In order to maintain and improve the properties of the lubricating oil, various additives have heretofore been provided; and these have been intended to improve the viscosity index, dispersancy, oxidative stability, etc. It is an object of this invention to provide an additive system which permits attainment of improved hydrocarbons. Other objects will be apparent to those skilled in the art.
In accordance with certain of its aspects, this invention is directed to a graft polymer comprising an oil-soluble, substantially linear, carbon-carbon backbone polymer having bonded thereto (i) first graft units derived from a first monomer amine containing a polymerizable, ethylenically unsaturated double bond and (ii) second units derived from a second monomer containing at least one of nitrogen, sulfur, or oxygen in a heterocyclic ring compound.
The charge polymer which may be employed in practice of the process of this invention may include an oil-soluble, substantially linear, carbon-carbon backbone polymer. Typical carbon-carbon backbone polymers prepared from monomers bearing an ethylenically unsaturated polymerizable double bond which may be employed include homopolymers or copolymers prepared from monomer ##STR1## wherein A may be: hydrogen; hydrocarbon such as alkyl, aryl, etc.; phenyl; acetate or less preferred acyloxy (typified by --COOR); halide; etc. R" may be divalent hydrocarbon typified by alkylene, alkarylene, aralkylene, cycloalkylene, arylene, etc.
Illustrative of such monomers may be acrylates, methacrylates, vinyl halides (such as vinyl chloride), styrene, olefins such as propylene, butylene, etc., vinyl acetate; dienes such as butadiene, isoprene, hexadiene, ethylidine norbornene, etc. Homopolymers of olefins, (such as polypropylene, polybutylene, etc.), dienes, (such as hydrogenated polyisoprene), or copolymers of ethylene with e.g., butylene and higher olefins, styrene with isoprene and/or butadiene may be employed. The preferred carbon-carbon backbone polymers include those selected from the group consisting of ethylene-propylene copolymers (EPM or EPR) and ethylene-propylene-diene third monomer terpolymers (EPDM or EPT).
When the charge polymer is an ethylene-propylene copolymer (EPM, also called EPR polymers), it may be formed by copolymerization of ethylene and propylene under known conditions preferably Ziegler-Natta reaction conditions. The preferred EPM copolymers contain units derived from ethylene in amount of 40-70 mole %, preferably 50-60 mole %, say 55 mole %, the remainder being derived from propylene.
The molecular weight M.sub.n of the EPM copolymers which may be employed may be 10,000-1,000,000, preferably 20,000-200,000, say 140,000. The molecular weight distribution may be characterized by M.sub.w /M.sub.n of less than about 15, preferably 1.2-10, say 1.6.
Illustrative EPM copolymers which may be employed in practice of the process of this invention may be those set forth in the following table, the first listed being preferred:
A. The Epsyn brand of EPM marketed by Copolymer Rubber and Chemical Corporation containing 60 mole % of units derived from ethylene and 40 mole % of units derived from propylene, having a molecular weight M.sub.n of 140,000 and a M.sub.w /M.sub.n of 1.6.
B. The Epcar 505 brand of EPM marketed by B. F. Goodrich Co., containing 50 mole % of units derived from ethylene and 50 mole % of units derived from propylene and having a M.sub.n of 25,000 and a polydispersity index of 2.5.
C. The Esprene brand of EPR marketed by Sumitomo Chemical Co., containing 55 mole % of units derived from ethylene and 45 mole % of units derived from propylene and having a M.sub.n of 25,000 and polydispersity index of 2.5;
When the charge polymer is a terpolymer of ethylene-propylene-diene third monomer (EPT or EPDM), it may be formed by copolymerization of ethylene, propylene and diene third monomer. The third monomer is commonly a non-conjugated diene typified by dicyclopentadiene; 1,4-hexadiene; or ethylidene norbornene. Polymerization is effected under known conditions generally comparable to those employed in preparing the EPM products. The preferred terpolymers contain units derived from ethylene in amount of 40-70 mole %, preferably 50-65 mole %, say 60 mole % and units derived from the propylene in amount of 20-60 mole %, preferably 30-50 mole %, say 38 mole % and units derived from third diene monomer in amount of 0.5-15 mole %, preferably 1-10 mole %, say 2 mole %. The molecular weight M.sub.n of the terpolymers may typically be 10,000-1,000,000, preferably 20,000-200,000, say 120,000. Molecular weight distribution of the useful polymers is preferably narrow viz a M.sub.w /M.sub.n of typically less than 15, preferably 1.5-10, say 2.2.
Illustrative EPT terpolymers which may be employed in practice of the process of this invention may be those set forth in the following table, the first listed being preferred:
A. The Epsyn 4006 brand of EPT marketed by Copolymer Rubber and Chemical Corp., containing 58 mole % of units derived from ethylene, 40 mole % of units derived from propylene, and 2 mole % of units derived from ethylidene norbornene and having a M.sub.n of 120,000 and a polydispersity index M.sub.w /M.sub.n of 2.2.
B. The Ortholeum 5655 brand of EPT marketed by DuPont containing 62 mole % of units derived from ethylene, 36 mole % of units derived from propylene, and 2 mole % of units derived from 1,4-hexadiene and having a M.sub.n of 75,000 and a polydispersity index M.sub.w /M.sub.n of 2.
C. The Ortholeum 2052 brand of EPT marketed by DuPont containing 62 mole % of units derived from ethylene, 36 mole % of units derived from propylene, and 2 mole % of units derived from 1,4-hexadiene and having a M.sub.n of 35,000 and a polydispersity M.sub.w /M.sub.n of 2.
D. The Royalene brand of EPT marketed by Uniroyal containing 60 mole % of units derived from ethylene, 37 mole % of units derived from propylene, and 3 mole % of units derived from dicyclopentadiene and having a M.sub.n of 100,000 and a polydispersity index M.sub.w /M.sub.n of 2.5.
E. The Epsyn 40A brand of EPT marketed by Copolymer Rubber and Chemical Corp., containing 60 mole % of units derived from ethylene, 37 mole % of units derived from propylene, and 3 mole % of units derived from ethylidene norbornene and having a M.sub.n of 140,000 and a polydispersity index M.sub.w /M.sub.n of 2.
The EPM and EPT polymers may contain minor portions (typically less than about 30%) of other units derived from other copolymerizable monomers.
It is a feature of the process of this invention that there may be grafted onto these oil-soluble, substantially linear carbon-carbon, backbone polymers, first graft units derived from a first graft amine monomer.
The functional amine monomer which may be grafted onto the EPM or EPT as the first graft monomer in practice of the process of this invention may be characterized by the formula RNR'R" wherein R is a hydrocarbon moiety possessing a polymerizable ethylenically unsaturated double bond. R may be an alkenyl or cycloalkenyl group (including such groups bearing inert substituents) typified by vinyl, allyl, C.dbd.C--C.sub.6 H.sub.4 --, etc. R',R" may be hydrogen or a hydrocarbon including alkyl, alkaryl, aralkyl, cycloalkyl, and aryl. The moiety-NR'R", may include a heterocyclic ring (formed by joining R' and R")as in the preferred N-vinyl pyrrolidone; 1-vinyl imidazol; or 4-vinyl pyridine. R' and R" may be a hydrogen or a hydrocarbon moiety containing nitrogen, sulfur, or oxygen. Illustrative amines which may be employed include those listed in the following table, the first listed, N-vinyl pyrrolidone, being preferred:
The first graft monomer may be a more complex amine reaction product formed by the reaction of an amine, typified by morpholine or N-methyl piperazine, and an epoxy compound typified by allyl glycidyl ether. It may be a monomer formed for example from the reaction of croton aldehyde and N-(3-aminopropyl) morpholine.
In practice of the process of this invention, 100 parts of charge EPM or EPT may be added to 100-1000 parts, say 300 parts of solvent. Typical solvent may be a hydrocarbon solvent such as hexane, heptane, tetrahydrofuran, or mineral oil. Preferred solvent may be a commercial hexane containing principally hexane isomers. Reaction mixture may then be heated to reaction conditions of 60.degree. C.-180.degree. C., preferably 150.degree. C.-170.degree. C., say 155.degree. C. at 15-300 psig, preferably 180-220 psig, say 200 psig.
In the preferred two step process, there are admitted to the reaction mixture first graft monomer, typically N-vinyl-pyrrolidone in amount of 1-40 parts, say 5 parts, and a solution in hydrocarbon of free radical initiator. Typical free radical initiators may include dicumyl peroxide, di-t-butyl peroxide, benzoyl peroxide, di-isopropyl peroxide, azobisisobutyronitrile, etc. The solvent is preferably the same as that in which the EPM or EPT is dissolved. The initiator may be added in amount of 0.2-10 parts, say 2 parts in 0.8-40 parts, say 16 parts of solvent.
The reaction is carried out at a temperature at least as high as the decomposition temperature of the initiator, typically 60.degree. C. or higher.
Reaction is typically carried out at 60.degree. C.-180.degree. C., say 155.degree. C. and 180-220 psig, say 200 psig during which time graft polymerization of the amine onto the base EPM or EPT polymer occurs. The final product graft polymer may be typically characterized by the presence of the following typical units: ##STR2##
Typically there may be 0.1-80 say 6 amine units per 1000 carbon atoms in the polymer backbone. R'" is saturated moiety derived from R.
It is a feature of the process of this invention that there may be bonded onto these oil-soluble, substantially linear, carbon-carbon, backbone polymers bearing units derived from a first graft monomer, units derived from a second functional monomer containing at least one of sulfur, nitrogen, or oxygen in a heterocyclic ring. Although it may be possible to effect bonding and graft polymerization simultaneously, it is preferred to effect graft polymerization first and thereafter bonding.
The second functional monomer which may be employed may be monocyclic or polycyclic; and the nitrogen, sulfur, and oxygen may be contained in the same or a different ring. In the preferred embodiment, the second functional monomer may be polycyclic and the nitrogen and sulfur may be in the same heterocyclic ring. This monomer may contain both heterocyclic and aromatic rings as is the case with the preferred phenothiazine.
The functional monomer may be a heterocyclic/aromatic or heterocyclic compound containing sulfur, nitrogen or oxygen, or combination thereof. The compound which may be used as the functional monomer include:
Preferred of the second functional monomers is phenothiazine which is a three-ring aromatic/heterocyclic compound containing nitrogen and sulfur in the same ring.
In practice of the process of this invention 100 parts of charge EPM or EPT (bearing units grafted thereon from the first graft monomers) may be added to 100-1000 parts, say 300 parts of diluent-solvent. Typical diluent-solvent may be a hydrocarbon solvent such as n-hexane, n-heptane, tetrahydrofuran, or mineral oil. Preferred solvent may be a commercial hexane containing principally hexane isomers. Reaction mixture may then be heated to reaction conditions of 60.degree. C.-180.degree. C., preferably 150.degree. C.-170.degree. C., say 155.degree. C. at 15-300 psig, preferably 180-220 psig, say 200 psig.
Second functional monomer, typically phenothiazine is admitted in amount of 1-40 parts, say 4 parts, as a solution in 1-40 parts, say 16 parts of diluent-solvent-typically tetrahydrofuran (THF). This is followed by a solution in hydrocarbon of free radical initiator. Typical free radical initiators may include dicumyl peroxide, di-t-butyl peroxide, benzoyl peroxide, di-isopropyl peroxide, azobisisobutyronitrile, etc. The solvent is preferably the same as that in which the EPM or EPT is dissolved. The initiator may be added in amount of 0.2-40 parts, say 2 parts in 0.8-40 parts, say 6 parts of solvent hexane.
The reaction is carried out at a temperature at least as high as the decomposition temperature of the initiator, typically 60.degree. C. or higher.
Reaction is typically carried out at 60.degree. C.-180.degree. C., say 155.degree. C. and 180-220 psig, say 200 psig during which time bonding of second monomer onto the base EPM or EPT polymer occurs. The final product graft polymer may be characterized by the presence of units derived from first and second monomers.
Typically there may be 0.1-60, say 3 units derived from second monomer per 1000 carbon atoms in the charge polymer backbone.
For ease of handling, the polymerization solvent may be exchanged with a heavier solvent such as SUS 100 Oil. Product graft polymer is typically obtained as a solution of 4-20 parts, say 8.5 parts thereof in 80-96 parts, say 91.5 parts of solvent.
Although it is preferred to graft the first monomer onto the base polymer and to thereafter bond the second monomer onto the so formed graft polymer, it is possible to effect simultaneous reaction of first and second monomers.
The product so formed may be an oil-soluble, substantially linear, carbon-carbon backbone polymer of molecular weight M.sub.n of preferably 10,000-1,000,000, preferably 20,000-200,000, say 140,000, bearing thereon (per 1,000 carbon atoms in the polymer backbone) 0.1-80 units preferably 1 15 units, say 6 units of first graft monomer and 0.1-60 units, preferably 1-12 units, say 3 units of second monomer.
It is a feature of this invention that the so-prepared polymers may find use in middle distillate fuel oils as dispersant when present in effective amount of 0.01-2 w %, say 0.5 w %. Typical fuel oils may include middle distillate fuel oils including kerosene, home heating oils, diesel fuel, etc.
Lubricating oils in which the dispersant viscosity index improvers of this invention may find use may include automotive, aircraft, marine, railway, etc., oils; oils used in spark ignition or compression ignition; summer or winter oils; etc. Typically the lubricating oils may be characterized by an ibp of 570.degree. F.-660.degree. F., say 610.degree. F.; an ep of 750.degree. F.-1200.degree. F., say 1020.degree. F.; and an API gravity of 25-31, say 29.
A typical lubricating oil in which the polymer of this invention may be present may be a standard SAE 5W-30 hydrocarbon motor oil formulation having the following composition:
Use of the additive of this invention makes it possible to readily increase the viscosity index by 25-40 units, say 35 units and to obtain improved ratings on the tests measuring the dispersancy of the system. The viscosity index is determined by ASTM Test D-445.
The novel polymers are also characterized as anti-oxidants as determined by the Bench Oxidation Test. In this test, a solution (8.5 wt. %) of test polymer in SNO-100 oil is diluted with SNO-130 oil to give a 1.5 wt. % solution of the test polymer. The solution is heated with stirring and air agitation. Samples are withdrawn periodically for analysis by Differential Infrared Absorption (DIR) to observe changes in the intensity of the carbonyl vibration band at 1710 cm.sup.-1. Higher carbonyl vibration band intensity indicates a lower thermal-oxidative stability of the sample.
Dispersancy is determined by the Bench VC Test (BVCT). In this test, the turbidity of an oil containing an additive is measured after heating the test oil to which has been added a standard blow-by. The result correlates with dispersancy is compared to three reference standards (Excellent, Good, and Fair) tested simultaneously with the test sample. The numerical rating decreases with an increase in dispersant effectiveness. Results lower than that of the Good Reference indicate that the additive is a good dispersant.
It appears that the first graft monomer used in practice of this invention provides improved dispersant properties to the base polymer (which provides viscosity index improvement); and the second functional monomer provides improved anti-oxidant properties. Thus it is possible to obtain product polymers which serve as multi-functional additives (dispersant, anti-oxidant, viscosity index improvers) when added to a hydrocarbon lubricating oil or to a synthetic type lubricating oil.
It is a feature of this invention that the so-prepared graft polymers may find use in lubricating oils as dispersant anti-oxidant, viscosity index improvers when present in effective amount of 0.2-5 w %, preferably 0.4-3 w %, say 0.9 wt %.
The novel polymers may also be characterized as deposit protection agents as measured by the Single Cylinder CEC MWM-B Diesel Engine Test (DIN 51361 Parts I, II, and IV). In this test, a solution (8.5 wt. %) of polymer in SNO-100 oil is blended into a fully formulated oil which does not contain a VI improver. Results are presented in "Merits", a higher merit evidencing better protection against deposits.
It is a feature of this invention that the polymer products of this invention may be used in middle distillate fuel oils to permit attainment of improved storage stability as measured by the Potential Deposit Test (PDT)-ASTM Test D-2274.
A rating of 1 or 2 is good; and a rating of 3 or 4 is unsatisfactory.
It is possible by use of the compositions of this invention to improve the PDT rating of a charge diesel fuel from 4+ to a satisfactory rating of 1 by use of only 25 PTB (pounds per thousand barrels) of active ingredient. When used in fuels, the additives may be present in amount of 0.25-250, preferably 10-100, say 25 pounds per thousand barrels (PTB).
Practice of the process of this invention will be apparent to those skilled in the art from the following examples wherein, as elsewhere in this specification, all parts are parts by weight unless otherwise set forth. Control examples are designated by an asterisk.
US Referenced Citations (5)
Foreign Referenced Citations (1)
| Number |
Date |
Country |
| 4729481 |
Nov 1972 |
JPX |
Divisions (1)
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Number |
Date |
Country |
| Parent |
726567 |
Apr 1985 |
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Patent Grant
4952637
