The invention relates to low-temperature-stabilized additives for fuel oils having a sulfur content of up 0.05% by weight, comprising fatty acid mixtures of

The present invention relates to mixtures of fatty acids and paraffin dispersants of improved low-temperature stability, and to their use for improving the lubricity of middle-distillate fuel oils.
Mineral oils and mineral-oil distillates which are used as fuel oils generally comprise 0.5% by weight or more of sulfur, which causes the formation of sulfur dioxide on combustion. In order to reduce the resultant environmental pollution, the sulfur content of fuel oils is constantly being reduced further. The EN 590 standard, which relates to diesel fuels, currently prescribes a maximum sulfur content of 350 ppm in Germany. In Scandinavia, fuel oils containing less than 50 ppm and in exceptional cases less than 10 ppm of sulfur are already in use. These fuel oils are generally produced by subjecting the fractions obtained from crude oil by distillation to reductive refining. During desulfurization, however, other substances are also removed which give the fuel oils a natural lubricity. These substances include, inter alia, polyaromatic and polar compounds.
However, it has now been found that the friction- and wear-reducing properties of fuel oils become worse with increasing degree of desulfurization. These properties are frequently so unsatisfactory that corrosion phenomena must be expected after only a short time on the materials lubricated by the fuel, such as, for example, distributor injection pumps of diesel engines. The maximum value for a 95% distillation point of a maximum of 360xc2x0 C. which has been prescribed in EN 590 since the year 2000 and the further reduction in the 95% distillation point to below 360xc2x0 C. and in some cases below 330xc2x0 C. which has in the meantime been effected in Scandinavia intensify these problems further.
The prior art has therefore described approaches which are intended to represent a solution to this problem (so-called lubricity additives).
EP-A-0 798 364 discloses salts and amides of mono- to tetracarboxylic acids having from 2 to 50 carbon atoms and aliphatic mono/polyamines having from 2 to 50 carbon atoms and from 1 to 10 nitrogen atoms as lubricity additives for low-sulfur diesel fuel. Preferred amines have 8-20 carbon atoms, such as, for example, coconut fatty amine, tallow fatty amine and oleylamine.
WO-A-95/33805 discloses the use of cold-flow improvers for improving the lubricity of low-sulfur middle distillates. The suitable substances mentioned include polar nitrogen-containing compounds which contain an NR13 group, where R13 is a hydrocarbon radical having from 8 to 40 carbon atoms, and may be in the form of a cation.
WO-A-96/18706 discloses, analogously to WO-A-95/33805, the use of the nitrogen-containing compounds mentioned therein in combination with lubricity additives.
WO-A-96123855 discloses, analogously to WO-A-95/33805, the use of the nitrogen-containing compounds mentioned therein in combination with detergent additives.
The fatty acids used in accordance with the prior art have the disadvantage that they solidify on storage at low temperatures, i.e. often at room temperature, usually at temperatures of from 0xc2x0 C. to at the latest xe2x88x925xc2x0 C., or deposit crystalline fractions and cause problems in handling. This problem can only be partially solved even by dilution with organic solvents, since fractions also crystallize from these solutions or the solution gels and solidifies. For use as lubricity additives, they therefore have to be diluted to a great extent or stored in heated storage containers and dispensed via heated lines.
The effectiveness of cold-flow improvers as lubricity additives is alone not sufficient, which means that either very high dispensing rates or synergists have to be employed.
The object on which the present invention is based was to find lubricity additives which improve the lubricity of middle distillates at reduced dispensing rates, but remain homogeneous, clear and in particular flowable even at low temperatures.
It has been found that mixtures of fatty acids with polar nitrogen-containing compounds which are effective as paraffin dispersants in middle distillates remain flowable and clear for an extended time even at significantly reduced temperatures, in some cases down to below xe2x88x9220xc2x0 C., in particular cases down to below xe2x88x9230xc2x0 C. and in special cases down to below xe2x88x9240xc2x0 C., and in addition improve the lubricity of middle distillates more efficiently than pure fatty acids of the prior art.
The invention thus relates to low-temperature-stabilized additives for fuel oils having a sulfur content of up to 0.05% by weight, comprising fatty acid mixtures of
A1) from 1 to 99% by weight of at least one saturated mono- or dicarboxylic acid having from 6 to 50 carbon atoms,
A2) from 1 to 99% by weight of at least one unsaturated mono- or dicarboxylic acid having from 6 to 50 carbon atoms, and
at least one polar nitrogen-containing compound which is effective as paraffin dispersant in middle distillates in an amount of from 0.01 to 90% by weight, based on the total weight of A1), A2) and B).
The invention furthermore relates to low-temperature-stabilized solutions of the additives according to the invention in organic solvents, where the solutions comprise from 1 to 90% by weight of solvent. Suitable solvents are aliphatic and/or aromatic hydrocarbons or hydrocarbon mixtures. The additives according to the invention preferably comprise 1-80%, especially 10-70%, in particular 25-60%, of solvent. The low-temperature-stabilized solutions according to the invention have a pour point of below xe2x88x9240xc2x0 C., preferably xe2x88x9245xc2x0 C., in particular xe2x88x9250xc2x0 C.
The invention furthermore relates to low-temperature-stabilized fatty acid mixtures of
A1) from 1 to 99% by weight of at least one saturated mono- or dicarboxylic acid having from 6 to 50 carbon atoms,
A2) from 1 to 99% by weight of at least one unsaturated mono- or dicarboxylic acid having from 6 to 50 carbon atoms, and
at least one polar nitrogen-containing compound which is effective as paraffin dispersant in middle distillates, in an amount of from 0.01 to 90% by weight, based on the total weight of A1), A2) and B).
The invention furthermore relates to fuel oils comprising, besides a middle distillate having a sulfur content of up to 0.05% by weight, fatty acid mixtures of
A1) from 1 to 99% by weight of at least one saturated mono- or dicarboxylic acid having from 6 to 50 carbon atoms,
A2) from 1 to 99% by weight of at least one unsaturated mono- or dicarboxylic acid having from 6 to 50 carbon atoms, and
at least one polar nitrogen-containing compound which is effective as paraffin dispersant in middle distillates, in an amount of from 0.01 to 90% by weight, based on the total weight of A1), A2) and B).
The invention furthermore relates to the use of said mixtures comprising constituents A and B for improving the lubrication properties of low-sulfur middle distillates having a sulfur content of up to 0.05% by weight.
Preferred fatty acids (constituent A) are those having 8-40 carbon atoms, in particular 12-22 carbon atoms. The alkyl radicals in the fatty acids essentially consist of carbon and hydrogen. However, they may carry further substituents, such as, for example, hydroxyl, halogen, amino or nitro groups, so long as these do not impair the predominant hydrocarbon character.
Constituent A2) may contain one or more double bonds and be of natural or synthetic origin. In the case of polyunsaturated carboxylic acids, their double bonds may be isolated or conjugated. The proportion of saturated fatty acids A1) in the mixture of A1) and A2) is preferably less than 20% by weight, in particular less than 10% by weight, especially less than 5% by weight. In preferred fatty acid mixtures, which is taken to mean the combination of A1) and A2) here, at least 50% by weight, in particular at least 75% by weight, especially at least 90% by weight, of the constituents contain one or more double bonds. These preferred fatty acid (mixtures) have iodine numbers of at least 40 g of I/100 g, preferably at least 80 g of I/100 g, in particular at least 125 g of I/100 g.
Examples of suitable fatty acids are lauric, tridecanoic, myristic, pentadecanoic, palmitic, margaric, stearic, isostearic, arachic and behenic acid, oleic and erucic acid, palmitoleic, myristoleic, linoleic, linolenic, elaeosteric and arachidonic acid, ricinoleic acid and fatty acid mixtures obtained from natural fats and oils, such as, for example, coconut oil, groundnut oil, fish, linseed oil, palm oil, rape oil, ricinene oil, castor oil, colza oil, soybean oil, sunflower oil and tall oil fatty acid.
Likewise suitable are dicarboxylic acids, such as dimeric fatty acids and alkyl- and alkenylsuccinic acids containing C8-C50-alk(en)yl radicals, preferably containing C8-C40-, in particular containing C12-C22-alkyl radicals. The alkyl radicals may be linear or branched (oligomerized alkene, PIB).
The fatty acids may furthermore comprise 1-40% by weight, especially 1-25% by weight, of resin acids, based on the weight of A1) and A2) together.
The additives according to the invention comprise, as constituent B, at least one polar nitrogen-containing compound which is effective as paraffin dispersant in middle distillates. Paraffin dispersants reduce the size of the paraffin crystals which precipitate out at low temperatures and have the effect that the paraffin particles do not settle out, but instead remain dispersed in colloidal form with significantly reduced sedimentation volition. Paraffin dispersants which have proven successful are oil-soluble polar compounds containing ionic or polar groups, for example amine salts and/or amides, which are obtained by reaction of aliphatic or aromatic amines, preferably long-chain aliphatic amines, with aliphatic or aromatic mono-, di-, tri- or tetracarboxylic acids or anhydrides thereof. Particularly preferred paraffin dispersants comprise products of the reaction of secondary fatty amines having from 8 to 36 carbon atoms, in particular dicoconut fatty amine, ditallow fatty amine and distearyl fatty amine. Other paraffin dispersants are copolymers of maleic anhydride and xcex1,xcex2-unsaturated compounds, which can, if desired, be reacted with primary monoalkylamines and/or aliphatic alcohols, the products of the reaction of alkenylspirobislactones with amines, and products of the reaction of terpolymers based on xcex1,xcex2-unsaturated dicarboxylic anhydrides, xcex1,xcex2-unsaturated compounds and polyoxyalkylene ethers of lower unsaturated alcohols. Alkylphenol-formaldehyde resins are also suitable as paraffin dispersants. Some suitable paraffin dispersants are listed below.
Some of the paraffin dispersants mentioned below are prepared by reaction of compounds containing an acyl group with an amine. This amine is a compound of the formula NR6R7R8, in which R6, R7 and R8 may be identical or different, and at least one of these groups is C8-C36-alkyl, C6-C36-cycloalkyl, C8-C36-alkenyl, in particular C12-C24-alkyl, C12-C24-alkenyl or cyclohexyl, and the other groups are either hydrogen, C1-C36-alkyl, C2-C36-alkenyl, cyclohexyl, or a group of the formula xe2x80x94(Axe2x80x94O)xxe2x80x94E or xe2x80x94(CH2)nxe2x80x94NYZ, in which A is an ethylene or propylene group, x is a number from 1 to 50, Exe2x95x90H, C1-C30-alkyl, C5-C12-cycloalkyl or C6-C30-aryl, and n is 2, 3 or 4, and Y and Z, independently of one another, are H, C1-C30-alkyl or xe2x80x94(Axe2x80x94O)x. The term acyl group here is taken to mean a functional group of the following formula:
Cxe2x95x90O
Products of the reaction of alkenylspirobislactones of the formula 4
in which each R is C8-C200-alkenyl, with amines of the formula NR6R7R8. Suitable reaction products are mentioned in EP-A-0 413 279. Depending on the reaction conditions, the reaction of compounds of the formula (4) with the amines gives amides or amide ammonium salts.
Amides or ammonium salts of aminoalkylenepolycarboxylic acids with secondary amines of the formulae 5 and 6
in which
R10 is a straight-chain or branched alkylene radical having from 2 to 6 carbons or the radical of the formula 7
in which R6 and R7 are, in particular, alkyl radicals having from 10 to 30, preferably from 14 to 24 carbon atoms, where all or some of the amide structures may also be in the form of the ammonium salt structure of the formula 8
The amides or amide ammonium salts or ammonium salts, for example of nitrilotriacetic acid, of ethylenediaminetetraacetic acid or of propylene-1,2-diaminetetraacetic acid, are obtained by reaction of the acids with from 0.5 to 1.5 mol of amine, preferably from 0.8 to 1.2 mol of amine, per carboxyl group. The reaction temperatures are from about 80 to 200xc2x0 C., with continuous removal of the water of reaction formed in order to prepare the amides. However, the reaction does not have to be continued completely to the amide, but instead from 0 to 100 mol % of the amine formed may be in the form of the ammonium salt. Under analogous conditions, the compounds mentioned under B1) can also be prepared.
Suitable amines of the formula 9
are, in particular, dialkylamines in which R6 and R7 are a straight-chain alkyl radical having from 10 to 30 carbon atoms, preferably from 14 to 24 carbon atoms. Specific mention may be made of dioleylamine, dipalmitylamine, dicoconut fatty amine and dibehenylamine and preferably ditallow fatty amine.
Quaternary ammonium salts of the formula 10
+NR6R7R8R11 Xxe2x88x92xe2x80x83xe2x80x83(10)
in which R6, R7 and R8 are as defined above, and R11 is C1-C30-alkyl, preferably C1-C22-alkyl, C1-C30-alkenyl, preferably C1-C22-alkenyl, benzyl or a radical of the formula xe2x80x94(CH2xe2x80x94CH2xe2x80x94O)nxe2x80x94R, where R12 is hydrogen or a fatty acid radical of the formula C(O)xe2x80x94R13, where R13+C6-C40-alkenyl, n is a number from 1 to 30, and X is halogen, preferably chlorine, or a methosulfate.
Examples which may be mentioned of quaternary ammonium salts of this type are the following: dihexadecyldimethylammonium chloride, distearyldimethylammonium chloride, products of the quaternization of esters of di- and triethanolamine with long-chain fatty acids (lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, oleic acid and fatty acid mixtures, such as coconut fatty acid, tallow fatty acid, hydrogenated tallow fatty acid and tall oil fatty acid), such as N-methyltriethanolammonium distearyl ester chloride, N-methyltriethanolammonium distearyl ester methosulfate, N,N-dimethyldiethanolammonium distearyl ester chloride, N-methyltriethanolammonium dioleyl ester chloride, N-methyltriethanol-ammonium trilauryl estermethosulfate, N-methyltriethanolammonium tristearyl ester methosulfate and mixtures thereof.
Compounds of the formula 11
in which R14 is CONR6R7 or CO2xe2x88x92 +H2NR6R7,
R15 and R16 are H, CONR172, CO2R17 or OCOR17, xe2x80x94OR17, xe2x80x94R17 or xe2x80x94NCOR17, and
R17 is alkyl, alkoxyalkyl or polyalkoxyalkyl and has at least 10 carbon atoms.
Preferred carboxylic acids or acid derivatives are phthalic acid (anhydride), trimellitic and pyromellitic acid (dianhydride), isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid (anhydride), maleic acid (anhydride) and alkenylsuccinic acid (anhydride). The formulation (anhydride) means that the anhydrides of said acids are also preferred acid derivatives.
If the compounds of the formula (11) are amides or amine salts, they are preferably obtained from a secondary amine which contains a hydrogen- and carbon-containing group having at least 10 carbon atoms.
R17 preferably contains from 10 to 30, in particular from 10 to 22, for example from 14 to 20, carbon atoms, and is preferably straight-chain or branched in the 1- or 2-position. The other hydrogen- and carbon-containing groups may be shorter, for example contain fewer than 6 carbon atoms, or may, if desired, have at least 10 carbon atoms. Suitable alkyl groups include methyl, ethyl, propyl, hexyl, decyl, dodecyl, tetradecyl, eicosyl and docosyl (behenyl).
Also suitable are polymers containing at least one amide or ammonium group bonded directly to the polymer skeleton, where the amide or ammonium group carries at least one alkyl group having at least 8 carbon atoms on the nitrogen atom. Polymers of this type can be prepared in various ways. One method is to use a polymer which contains a plurality of carboxyl or carboxylic anhydride groups and to react this polymer with an amine of the formula NHR6R7 in order to obtain the desired polymer.
Suitable polymers for this purpose are generally copolymers of unsaturated esters, such as C1-C40-alkyl (meth)acrylates, di(C1-C40-alkyl) fumarates, C1-C40-alkyl vinyl ethers, C1-C40-alkyl vinyl esters or C2-C40-olefins (linear, branched or aromatic) with unsaturated carboxylic acids or reactive derivatives thereof, such as, for example, carboxylic anhydrides (acrylic acid, methacrylic acid, maleic acid, fumaric acid, tetrahydrophthalic acid, citraconic acid, preferably maleic anhydride).
Carboxylic acids are preferably reacted with from 0.1 to 1.5 mol, in particular from 0.5 to 1.2 mol, of amine per acid group, while carboxylic anhydrides are preferably reacted with from 0.1 to 2.5 mol, in particular from 0.5 to 2.2 mol, of amine per acid anhydride group, with amides, ammonium salts, amide ammonium salts or imides being formed, depending on the reaction conditions. Thus, copolymers containing unsaturated carboxylic anhydrides give half amide and half amine salts on reaction with a secondary amine owing to the reaction with the anhydride group. Water can be eliminated by heating with formation of the diamide.
Particularly suitable examples of amide group-containing polymers for use in accordance with the invention are the following:
Copolymers (a) of a dialkyl fumarate, maleate, citraconate or itaconate with maleic anhydride, or (b) of vinyl esters, for example vinyl acetate or vinyl stearate, with maleic anhydride, or (c) of a dialkyl fumarate, maleate, citraconate or itaconate with maleic anhydride and vinyl acetate.
Particularly suitable examples of these polymers are copolymers of didodecyl fumarate, vinyl acetate and maleic anhydride; ditetradecyl fumarate, vinyl acetate and maleic anhydride; dihexadecyl fumarate, vinyl acetate and maleic anhydride; or the corresponding copolymers in which the itaconate is used instead of the fumarate.
In the above-mentioned examples of suitable polymers, the desired amide is obtained by reaction of the polymer containing anhydride groups with a secondary amine of the formula HNR6R7 (if desired in addition with an alcohol if an ester-amide is formed). If polymers containing an anhydride group are reacted, the resultant amino groups will be ammonium salts and amides. Polymers of this type can be used with the proviso that they contain at least two amide groups.
It is essential that the polymer containing at least two amide groups contains at least one alkyl group having at least 10 carbon atoms. This long-chain group, which may be a straight-chain or branched alkyl group, may be bonded via the nitrogen atom of the amide group.
The amines which are suitable for this purpose may be represented by the formula R6R7NH and the polyamines by R6NH[R19NH]xR7, where R19 is a divalent hydrocarbon group, preferably an alkylene or hydrocarbon-substituted alkylene group, and x is an integer, preferably between 1 and 30. One of the two or both radicals R6 and R7 preferably contains at least 10 carbon atoms, for example from 10 to 20 carbon atoms, for example dodecyl, tetradecyl, hexadecyl or octadecyl.
Examples of suitable secondary amines are dioctylamine and those which contain alkyl groups having at least 10 carbon atoms, for example didecylamine, didodecylamine, dicoconut amine (i.e. mixed C12-C14-amines), dioctadecylamine, hexadecyloctadecylamine, di(hydrogenated tallow) amine (approximately 4% by weight of n-C14-alkyl, 30% by weight of n-C10-alkyl, 60% by weight of n-C18-alkyl, the remainder is unsaturated).
Examples of suitable polyamines are N-octadecylpropanediamine, N,Nxe2x80x2-dioctadecylpropanediamine, N-tetradecylbutanediamine and N,Nxe2x80x2-dihexadecylhexanediamine, N-(coconut)propylenediamine (C12/C14-alkylpropylene-diamine), N-(tallow)propylenediamine (C12/C18-alkylpropylenediamine).
The amide-containing polymers usually have a mean molecular weight (number average) of from 1000 to 500,000, for example from 10,000 to 100,000.
Copolymers of styrene, derivatives thereof or aliphatic olefins having from 2 to 40 carbon atoms, preferably having from 6 to 20 carbon atoms, and olefinically unsaturated carboxylic acids or carboxylic anhydrides which have been reacted with amines of the formula HNR6R7. The reaction can be carried out before or after the polymerization.
In detail, the structural units of the copolymers are derived from, for example, maleic acid, fumaric acid, tetrahydrophthalic acid, citraconic acid, preferably maleic anhydride. They can be employed either in the form of their homopolymers or in the form of the copolymers. Suitable comonomers are the following: styrene and alkylstyrenes, straight-chain and branched olefins having from 2 to 40 carbon atoms, and mixtures thereof with one another. Examples which may be mentioned are the following: styrene, xcex1-methyl-styrene, dimethylstyrene, xcex1-ethylstyrene, diethylstyrene, i-propylstyrene, tert-butylstyrene, ethylene, propylene, n-butylene, diisobutylene, decene, dodecene, tetradecene, hexadecene and octadecene. Preference is given to styrene and isobutene, particular preference is given to styrene.
Examples of polymers which may be mentioned individually are the following: polymaleic acid, a molar styrene-maleic acid copolymer with an alternating structure, styrene-maleic acid copolymers with a random structure in the ratio 10:90 and an alternating copolymer of maleic acid and i-butene. The molecular weights of the polymers are generally from 500 g/mol to 20,000 g/mol, preferably from 700 to 2000 g/mol.
The reaction of the polymers or copolymers with the amines is carried out at temperatures of from 50 to 200xc2x0 C. over the course of from 0.3 o 30 hours. The amine here is used in amounts of approximately one mole per mole of copolymerized dicarboxylic anhydride, i.e. from about 0.9 to 1.1 mol/mol. The use of larger or smaller amounts is possible, but does not bring any advantage. If larger amounts than one mole are used, ammonium salts are partly obtained, since the formation of a second amide group requires higher temperatures, longer residence times and separation of water. If smaller amounts than one mole are used, complete conversion to the monoamide does not take place, and a correspondingly reduced action is obtained.
Instead of the subsequent reaction of the carboxyl groups in the form of the dicarboxylic anhydride with amines to give the corresponding amides, it is sometimes of advantage to prepare the monoamides of the monomers and then to copolymerize them directly in the polymerization. Usually, however, this is much more technically complex, since the amines are able to add onto the double bond of the monomeric mono- and dicarboxylic acid, and copolymerization is then no longer possible.
Copolymers consisting of from 10 to 95 mol % of one or more alkyl acrylates or alkyl methacrylates having C1-C26-alkyl chains and from 5 to 90 mol % of one or more ethylenically unsaturated dicarboxylic acids or anhydrides thereof, where the copolymers have substantially been reacted with one or more primary or secondary amines to give the monoamides or amide/ammonium salts of the dicarboxylic acids.
The copolymers consist of from 10 to 95 mol %, preferably from 40 to 95 mol % and particularly preferably from 60 to 90 mol %, of alkyl (meth)acrylates and from 5 to 90 mol %, preferably from 5 to 60 mol % and particularly preferably from 10 to 40 mol % of the olefinically unsaturated dicarboxylic acid derivatives. The alkyl groups of the alkyl (meth)acrylates contain from 1 to 26, preferably from 4 to 22 and particularly preferably from 8 to 18 carbon atoms. They are preferably straight-chain and unbranched. However, it is also possible for up to 20% by weight of cyclic and/or branched components to be present.
Examples of particularly preferred alkyl (meth)acrylates are n-octyl (meth)acrylate, n-decyl (meth)acrylate, n-dodecyl (meth)acrylate, n-tetradecyl (meth)acrylate, n-hexadecyl (meth)acrylate and n-octadecyl (meth)acrylate, and mixtures thereof.
Examples of ethylenically unsaturated dicarboxylic acids are maleic acid, tetrahydrophthalic acid, citraconic acid and itaconic acid, and anhydrides thereof, and fumaric acid. Preference is given to maleic anhydride.
Suitable amines are compounds of the formula HNR6R7.
In general, it is advantageous to employ the dicarboxylic acids in the form of the anhydrides, if available, in the copolymerization, for example maleic anhydride, itaconic anhydride, citraconic anhydride and tetrahydrophthalic anhydride, since the anhydrides copolymerize better with the (meth)acrylates. The anhydride groups of the copolymers can then be reacted directly with the amines. The reaction of the polymers with the amines is carried out at temperatures of from 50 to 200xc2x0 C. over the course of from 0.3 to 30 hours. The amine here is used in amounts of from approximately one to two moles per mole of copolymerized dicarboxylic anhydride, i.e. from about 0.9 to 2.1 mol/mol. The use of larger or smaller amounts is possible, but does not bring any advantage. If larger amounts than 2 mol are used, free amine is present. If smaller amounts than one mole are used, complete conversion to the monoamide does not take place, and a correspondingly reduced action is obtained.
In some cases, it may be advantageous for the amide/ammonium salt structure to be built up from two different amines. Thus, for example, a copolymer of lauryl acrylate and maleic anhydride can firstly be reacted with a secondary amine, such as hydrogenated ditallow fatty amine, to give the amide, after which the free carboxyl group originating from the anhydride is neutralized using another amine, for example 2-ethylhexylamine, to give the ammonium salt. The reverse procedure is equally conceivable: reaction is firstly carried out with ethylhexylamine to give the monoamide, then with ditallow fatty amine to give the ammonium salt. Preferably at least one amine is used here which has at least one straight-chain, unbranched alkyl group having more than 16 carbon atoms. It is not important here whether this amine is present in the build-up of the amide structure or as ammonium salt of the dicarboxylic acid.
Instead of the subsequent reaction of the carboxyl groups or of the dicarboxylic anhydride with amines to give the corresponding amides or amide/ammonium salts, it may sometimes be advantageous to prepare the monoamides or amide/ammonium salts of the monomers and then to copolymerize these directly in the polymerization. Usually, however, this is much more technically complex, since the amines are able to add onto the double bond of the monomeric dicarboxylic acids, and copolymerization is then no longer possible.
Terpolymers based on xcex1,xcex2-unsaturated dicarboxylic anhydrides, xcex1,xcex2-unsaturated compounds and polyoxyalkylene ethers of lower, unsaturated alcohols which comprise 20-80 mol %, preferably 40-60 mol %, of divalent structural units of the formulae 12 and/or 14, and, if desired, 13, where the structural units 13 originate from unreacted anhydride radicals,
where
R22 and R23, independently of one another, are hydrogen or methyl,
a and b are zero or one and a+b is one,
R24 and R25 are identical or different and are xe2x80x94NHR6, N(R6)2 and/or xe2x80x94OR27 groups, and R27 is a cation of the formula H2N(R6)2 or H3NR6,
19-80 mol %, preferably 39-60 mol %, of divalent structural units of the formula 15
in which
R28 is hydrogen or C1-C4-alkyl, and
R29 is C6-C60-alkyl or C6-C18-aryl, and
1-30 mol %, preferably 1-20 mol %, of divalent structural units of the formula 16
in which
R30 is hydrogen or methyl,
R31 is hydrogen or C1-C4-alkyl,
R33 is C1-C4-alkylene,
m is a number from 1 to 100,
R32 is C1-C24-alkyl, C5-C20-cycloalkyl, C6-C18-aryl or xe2x80x94C(O)xe2x80x94R34, where
R34 is C1-C40-alkyl, C5-C10-cycloalkyl or C6-C18-aryl.
The above-mentioned alkyl, cycloalkyl and aryl radicals may be substituted or unsubstituted. Suitable substituents of the alkyl and aryl radicals are, for example, (C1-C6)-alkyl, halogens, such as fluorine, chlorine, bromine and iodine, preferably chlorine, and (C1-C6)-alkoxy.
Alkyl here is a straight-chain or branched hydrocarbon radical. Specific mention may be made of the following: n-butyl, tert-butyl, n-hexyl, n-octyl, decyl, dodecyl, tetradecyl, hexadecyl, octadecyl, dodecenyl, tetrapropenyl, tetradecenyl, pentapropenyl, hexadecenyl, octadecenyl and eicosanyl, or mixtures, such as coconut alkyl, tallow fatty alkyl and behenyl.
Cycloalkyl here is a cyclic aliphatic radical having 5-20 carbon atoms. Preferred cycloalkyl radicals are cyclopentyl and cyclohexyl.
Aryl here is a substituted or unsubstituted aromatic ring system having from 6 to 18 carbon atoms.
The terpolymers consist of the divalent structural units of the formulae 12 and 14, and 15 and 16, and, if desired, 13. They additionally only contain, in a manner known per se, the end groups formed in the polymerization by initiation, inhibition and chain termination.
In detail, structural units of the formulae 12 to 14 are derived from xcex1,xcex2-unsaturated dicarboxylic anhydrides of the formulae 17 and 18
such as maleic anhydride, itaconic anhydride, citraconic anhydride, preferably maleic anhydride.
The structural units of the formula 15 are derived from xcex1-xcex2-unsaturated compounds of the formula 19.
The following xcex1,xcex2-unsaturated olefins may be mentioned by way of example: styrene, xcex1-methylstyrene, dimethylstyrene, xcex1-ethylstyrene, diethylstyrene, i-propylstyrene, tert-butylstyrene, diisobutylene and xcex1-olefins, such as decene, dodecene, tetradecene, pentadecene, hexadecene, octadecene, C20-xcex1-olefin, C24-xcex1-olefin, C30-xcex1-olefin, tripropenyl, tetrapropenyl, pentapropenyl and mixtures thereof. Preference is given to xcex1-olefins having from 10 to 24 carbon atoms and styrene, particularly preferably xcex1-olefins having from 12 to 20 carbon atoms.
The structural units of the formula 16 are derived from polyoxyalkylene ethers of lower, unsaturated alcohols of the formula 20
The monomers of the formula 20 are products of the etherification (R32+xe2x80x94C(O)R34) or esterification (R32+xe2x80x94C(O)R34) of polyoxyalkylene ethers (R32xe2x95x90H).
The polyoxyalkylene ethers (R32xe2x95x90H) can be prepared by processes known per se by the addition of xcex1-olefin oxides, such as ethylene oxide, propylene oxide and/or butylene oxide, onto polymerizable, lower, unsaturated alcohols of the formula 21
Polymerizable, lower, unsaturated alcohols of this type are, for example, allyl alcohol, methallyl alcohol, butenols, such as 3-buten-1-ol and 1-buten-3-ol, or methylbutenols, such as 2-methyl-3-buten-1-ol, 2-methyl-3-buten-2-ol and 3-methyl-3-buten-1-ol. Preference is given to the products of the addition of ethylene oxide and/or propylene oxide onto allyl alcohol. Subsequent etherification of these polyoxyalkylene ethers to give compounds of the formula 20 in which R32+C1-C24-alkyl, cycloalkyl or aryl is carried out by processes known per se. Suitable processes are disclosed, for example, in J. March, Advanced Organic Chemistry, 2nd Edition, pp. 357f (1977). These products of the etherification of polyoxyalkylene ethers can also be prepared by adding xcex1-olefin oxides, preferably ethylene oxide, propylene oxide and/or butylene oxide, onto alcohols of the formula 22.
In the monomers of the formula 20, the index m indicates the degree of alkoxylation, i.e. the number of moles of xcex1-olefin which are adducted per mole of the formula 20 or 21.
Examples which may be mentioned of suitable primary amines for the preparation of the terpolymers are the following:
n-hexylamine, n-octylamine, n-tetradecylamine, n-hexadecylamine,
n-stearylamine or also N,N-dimethylaminopropylenediamine, cyclohexyl-amine, dehydroabietylamine and mixtures thereof.
Examples which may be mentioned of secondary amines which are suitable for the preparation of the terpolymers are the following: didecylamine, ditetradecylamine, distearylamine, dicoconut fatty amine, ditallow fatty amine and mixtures thereof.
The terpolymers have K values (measured by the Ubbelohde method in 5% strength by weight solution in toluene at 25xc2x0 C.) of from 8 to 100, preferably from 8 to 50, corresponding to mean molecular weights (MW) of from about 500 to 100,000. Suitable examples are listed in EP 606 055.
Products of the reaction of alkanolamines and/or polyether-amines with polymers containing dicarboxylic anhydride groups, which comprise 20-80 mol %, preferably 40-60 mol %, of divalent structural units of the formulae 25 and 27 and, if desired, 26.
where
R22 and R23, independently of one another, are hydrogen or methyl, a and b are zero or 1, and a+b is 1,
R37=xe2x80x94OH, xe2x80x94Oxe2x80x94[C1-C30-alkyl], xe2x80x94NR6R7, xe2x80x94OsNrR6R7H2
R38=R37 or NR6R39
R39=xe2x80x94(Axe2x80x94O)xxe2x80x94E
where
A=an ethylene or propylene group,
x=from 1 to 50,
E=H, C1-C30-alkyl, C5-C12-cycloalkyl or C6-C30-aryl, and
80-20 mol %, preferably 60-40 mol %, of divalent structural units of the formula 15.
In detail, the structural units of the formulae 25, 26 and 27 are derived from xcex1,xcex2-unsaturated dicarboxylic anhydrides of the formulae 17 and/or 18.
The structural units of the formula 15 are derived from the xcex1,xcex2-unsaturated olefins of the formula 19. The above-mentioned alkyl, cycloalkyl and aryl radicals have the same meanings as under 8.
The radicals R37 and R38 in the formula 25 and R39 in the formula 27 are derived from polyether-amines or alkanolamines of the formulae 28 a) and b), amines of the formula NR6R7R8 and, where appropriate, alcohols having from 1 to 30 carbon atoms.
In these formulae,
R53 is hydrogen, C6-C40-alkyl or
R54 is hydrogen or C1-C4-alkyl,
R55 is hydrogen, C1- to C4-alkyl, C5- to C12-cycloalkyl or C6- to C30-aryl
R56 and R57, independently of one another, are hydrogen, C1- to C22-alkyl, C2- to C22-alkenyl or Zxe2x80x94OH,
Z is C2- to C4-alkylene, and
n is a number from 1 to 1000.
The structural units of the formulae 17 and 18 have preferably been derivatized using mixtures of at least 50% by weight of alkylamines of the formula HNR6R7R8 and at most 50% by weight of polyether-amines or alkanolamines of the formulae 28 a) and b).
The polyether-amines employed can be prepared, for example, by reductive amination of polyglycols. Polyether-amines containing a primary amino group are furthermore prepared by addition of polyglycols onto acrylonitrile followed by catalytic hydrogenation. In addition, polyether-amines can be obtained by reaction of polyethers with phosgene or thionyl chloride followed by amination to give the polyether-amine. The polyether-amines employed in accordance with the invention are commercially available (for example) under the name (copyright)Jeffamine (Texaco). Their molecular weight is up to 2000 g/mol, and the ethylene oxide/propylene oxide ratio is from 1:10 to 6:1. Another possibility for the derivatization of the structural units of the formulae 17 and 18 comprises employing an alkanolamine of the formula instead of the polyether-amines and subsequently subjecting the product to oxyalkylation.
From 0.01 to 2 mol, preferably from 0.01 to 1 mol, of alkanolamine are employed per mole of anhydride. The reaction temperature is from 50 to 100xc2x0 C. (amide formation). In the case of primary amines, the reaction is carried out at temperatures above 100xc2x0 C. (imide formation).
The oxyalkylation is usually carried out at temperatures of from 70 to 170xc2x0 C. with catalysis by bases, such as NaOH or NaOCH3, by introducing gaseous alkylene oxides, such as ethylene oxide (EO) and/or propylene oxide (PO). From 1 to 500 mol, preferably from 1 to 100 mol, of alkylene oxide are usually added per mole of hydroxyl groups.
Examples of suitable alkanolamines which may be mentioned are the following: monoethanolamine, diethanolamine, N-methylethanolamine, 3-amino-propanol, isopropanol, diglycolamine, 2-amino-2-methylpropanol and mixtures thereof.
Examples of primary amines which may be mentioned are the following: n-hexylamine, n-octylamine, n-tetradecylamine, n-hexadecylamine, n-stearylamine or also N,N-dimethylaminopropylenediamine, cyclohexylamine, dehydroabietylamine and mixtures thereof.
Examples of secondary amines which may be mentioned are the following: didecylamine, ditetradecylamine, distearylamine, dicoconut fatty amine, ditallow fatty amine and mixtures thereof.
Examples of alcohols which may be mentioned are the following: methanol, ethanol, propanol, isopropanol, n-, sec-, and tert-butanol, octanol, tetradecanol, hexadecanol, octadecanol, tallow fatty alcohol, behenyl alcohol and mixtures thereof. Suitable examples are listed in EP-A-688 796.
Copolymers and terpolymers of N-C6-C24-alkylmaleimide with C1-C30-vinyl esters, vinyl ethers and/or olefins having from 1 to 30 carbon atoms, such as, for example, styrene or xcex1-olefins. These can be obtained firstly by reaction of a polymer containing anhydride groups with amines of the formula H2NR6 or by imidation of the dicarboxylic acid followed by copolymerization. The preferred dicarboxylic acid here is maleic acid or maleic anhydride. Preference is given here to copolymers comprising from 10 to 90% by weight of C6-C24-xcex1-olefins and from 90 to 10% by weight of N-C6-C22-alkylmaleimide.
The mixing ratio between A and B can vary within broad limits. Thus, even small amounts of B of from 100 ppm to 50,000 ppm, preferably from 1000 ppm to 10,000 ppm, in fatty acid solutions act as low-temperature additive for A. They are capable of suppressing the inherent crystallization of the fatty acid, which results in a reduction in the cloud point, and prevent the sedimentation of crystals formed and thus facilitate easy handling at reduced temperatures. For specific problem solutions, however, from 5% to 50%, in particular cases up to 90%, of constituent B, based on the amount of constituent A, may also be present. In particular, the inherent pour point of the additive is lowered and the lubricity of the additive-containing oil is improved. Accordingly, the preferred mixing ratio of A:B is from 1:10 to 1:0.0001, in particular from 1:4 to 1:0.0005, especially from 1:1 to 1:0.001.
The additives according to the invention are added to oils in amounts of from 0.001 to 0.5% by weight, preferably from 0.001 to 0.1% by weight. They can be employed as such or also dissolved in solvents, such as, for example, aliphatic and/or aromatic hydrocarbons or hydrocarbon mixtures, such as, for example, toluene, xylene, ethylbenzene, decane, pentadecane, gasoline fractions, kerosine or commercial solvent mixtures, such as solvent naphtha, (copyright)Shellsol AB, (copyright)Solvesso 150, (copyright)Solvesso 200, (copyright)Exxsol, (copyright)Isopar and (copyright)Shellsol D grades. The additives according to the invention preferably comprise 1-80%, especially 10-70%, in particular 25-60%, of solvent. The additives, which can also be employed without problems at low temperatures of, for example, xe2x88x9240xc2x0 C. or lower, improve the lubricity of the additive-containing oils and their low-temperature and corrosion-protection properties.
For the preparation of additive packages for special problem solutions, the additives according to the invention may also be employed together with one or more oil-soluble co-additives which, even on their own, improve the low-temperature flow properties and/or lubricity of crude oils, lubricating oils or fuel oils. Examples of co-additives of this type are vinyl acetate-containing copolymers or terpolymers of ethylene, comb polymers, alkylphenol-aldehyde resins and oil-soluble amphiphiles.
Thus, mixtures of the additives according to the invention with copolymers which comprise from 10 to 40% by weight of vinyl acetate and from 60 to 90% by weight of ethylene have proven highly successful. According to a further embodiment of the invention, the additives according to the invention are employed as a mixture with ethylene-vinyl acetate-vinyl neononanoate terpolymers or ethylene-vinyl acetate-vinyl neodecanoate terpolymers for improving the flow properties of mineral oils or mineral oil distillates. Besides ethylene, the terpolymers of vinyl neononanoate or of vinyl neodecanoate comprise from 10 to 35% by weight of vinyl acetate and from 1 to 25% by weight of the respective neo compound. Besides ethylene and from 10 to 35% by weight of vinyl esters, further preferred copolymers also comprise from 0.5 to 20% by weight of olefin, such as diisobutylene, 4-methylpentene or norbornene. The mixing ratio of the additives according to the invention with the ethylene-vinyl acetate copolymers described above or the terpolymers of ethylene, vinyl acetate and the vinyl esters of neononanoic or of neodecanoic acid is (in parts by weight) from 20:1 to 1:20, preferably from 10:1 to 1:10.
The additives according to the invention can thus be employed together with alkylphenol-formaldehyde resins. In a preferred embodiment of the invention, these alkylphenol-formaldehyde resins are those of the formula
in which R50 is C4-C50-alkyl or -alkenyl, R51 is ethoxy and/or propoxy, n is a number from 5 to 100, and p is a number from 0 to 50.
Finally, in a further embodiment of the invention, the additives according to the invention are used together with comb polymers. These are taken to mean polymers in which hydrocarbons radicals having at least 8, in particular at least 10, carbon atoms are bonded to a polymer backbone. These are preferably homopolymers whose alkyl side chains contain at least 8 and in particular at least 10 carbon atoms. In the case of copolymers, at least 20%, preferably at least 30%, of the monomers have side chains (cf. Comb-like Polymers-Structure and Properties; N.A. Plate and V.P. Shibaev, J. Polym. Sci. Macromolecular Revs. 1974, 8, 117 ff). Examples of suitable comb polymers are, for example, fumarate-vinyl acetate copolymers (of. EP 0 153 176 A1), copolymers of a C6-C24-xcex1-olefin and and and Nxe2x80x94C8xe2x80x94C22-alkylmaleimide (cf. EP 0 320 766), furthermore esterified olefin/maleic anhydride copolymers, polymers and copolymers of xcex1-olefins and esterified copolymers of styrene and maleic anhydride.
Comb polymers can be described, for example, by the formula
in which
A is Rxe2x80x2, COORxe2x80x2, OCORxe2x80x2, Rxe2x80x3xe2x80x94COORxe2x80x2 or ORxe2x80x2;
D is H, CH3, A or R;
E is H or A;
G is H, Rxe2x80x3, Rxe2x80x3xe2x80x94COORxe2x80x2, an aryl radical or a heterocyclic radical;
M is H, COORxe2x80x3, OCORxe2x80x3, ORxe2x80x3 or COOH;
N is H, Rxe2x80x3, COORxe2x80x3, OCOR, COOH or an aryl radical;
Rxe2x80x2 is a hydrocarbon chain having 8-150 carbon atoms;
Rxe2x80x3 is a hydrocarbon chain having from 1 to 10 carbon atoms;
m is a number from 0.4 to 1.0; and
n is a number from 0 to 0.6.
The mixing ratio (in parts by weight) of the additives according to the invention with resins or comb polymers is in each case from 1:10 to 20:1, preferably from 1:1 to 10:1.
The additives according to the invention are suitable for improving the lubrication properties of animal, vegetable, mineral or synthetic fuel oils in only small added amounts. Their improved low-temperature properties make warming and/or dilution during storage and use unnecessary. In addition, they simultaneously improve the low-temperature and corrosion-protection properties of the additive-containing oils. At the same time, the emulsification properties of the additive-containing oils are impaired less than is the case with the lubrication additives from the prior art. The additives according to the invention are particularly suitable for use in middle distillates. The term middle distillates is taken to mean, in particular, mineral oils which are obtained by distillation of crude oil and boil in the range from 120 to 450xc2x0 C., for example kerosine, jet fuel, diesel and heating oil. The oils may also comprise or consist of alcohols, such as methanol and/or ethanol. The additives according to the invention are preferably used in middle distillates which contain 0.05% by weight or less of sulfur, particularly preferably less than 350 ppm of sulfur, in particular less than 200 ppm of sulfur and in special cases less than 50 ppm of sulfur. In general, these are middle distillates which have been subjected to reductive refining and which therefore only contain small proportions of polyaromatic and polar compounds which give them a natural lubricity. The additives according to the invention are furthermore preferably used in middle distillates which have 95% distillation points below 370xc2x0 C., in particular 350xc2x0 C. and in special cases below 330xc2x0 C. They can also be employed as components in lubricating oils.
The mixtures can be used alone or also together with other additives, for example with other pour point depressants or dewaxing auxiliaries, with corrosion inhibitors, antioxidants, sludge inhibitors, dehazers, conductivity improvers, lubricity additives and additives for lowering the cloud point. They are furthermore successfully employed together with additive packages which comprise, inter alia, known ash-free dispersion additives, detergents, antifoams and corrosion inhibitors.
The improved low-temperature stability and the effectiveness of the additives according to the invention as lubricity additives is explained in greater detail by the following examples.

Fuel oils having improved lubricity comprising mixtures of fatty acids with paraffin dispersants, and a lubrication-improving additive

Abstract: B) at least one polar nitrogen-containing compound which is effective as paraffin dispersant in middle distillates, in an amount of from 0.01 to 90% by weight, based on the total weight of A1), A2) and B),

Abstract: and to the use of said mixtures for improving the lubrication properties of low-sulfur middle distillates.


A fluid ejecting method and system include one or more fluid ejectors within a fluid ejector frame and an interposer frame and movably mounted upon a fluid ejector carriage. The fluid ejector carriage traverses across a recording medium for placing swaths of fluid droplets upon the recording medium. A biasing structure urges the fluid ejector frame to a first position to obtain highly accurate and repeatable placement of fluid droplets when the fluid ejector frame is in the first position. A second position of the fluid ejector frame is achieved by energizing a position actuator to move the fluid ejector frame from the first position to the second position to obtain highly accurate and repeatable placement of fluid droplets when the fluid ejector frame is in the second position. The recording medium is advanced separately upon completing a set of at least one swath of fluid droplets.

1. Field of Invention
This invention relates to mechanisms and methods for advancing a fluid ejection system relative to a receiving medium.
2. Description of Related Art
Partial width fluid ejection systems are known to use an advance mechanism that advances a receiving medium relative to a fluid ejector head in a process, or slow scan, direction in conjunction with a carriage that moves along a fast scan direction to facilitate ejecting fluid onto the receiving medium. In a typical fluid ejecting system using this combination of movements between the advance mechanism and the carriage, the advance mechanism moves the receiving medium in a direction perpendicular to the direction of movement of the carriage along the fast scan direction. The carriage houses at least one fluid ejector having a plurality of fluid-ejecting nozzles from which droplets of fluid are placed on the receiving medium in swaths according to the transversing movement of the carriage in the fast scan direction across the receiving medium. The receiving medium advance motion and the carriage motion are coordinated to the extent that the receiving medium advance is stopped while the carriage travels across the receiving medium to place fluid upon the receiving medium.
A variety of configurations have been used to date to provide the dual motions necessary for placing the ejecting fluid upon the receiving medium using a carriage. For example, some known systems use a servo-system including an encoder to accurately move a receiving medium in two modes. The first mode advances the receiving medium a designated distance at the completion of each swath of ejected fluid from the one or more fluid ejector on the carriage. The servo motor provides the first motion mode for advancing the receiving medium. The servo motor provides a second, finer, motion mode to the receiving medium as well. The second, finer, motion mode positions the receiving medium a necessary, though relatively smaller, distance compared to the first advance distance the receiving medium is moved as provided by the servo-motor. The second, finer, motion aligns the recording medium relative to the one or more fluid ejector for receiving second, or subsequent, swaths off fluid ejected from the one or more fluid ejector.
Thus, the dual movements in this servo-motor system require fairly precise co-ordination between the servo-motor and the receiving medium relative to the one or more fluid ejectors. However, servo-motors are prone to deviations in placing the receiving medium, resulting in less accurate placement of fluid upon the receiving medium. Moreover, in those servo-motor printing systems that move the receiving medium in the advance directions in two modes, the accuracy of movement is questionable as well, since it is very difficult to move the receiving medium consistently in the second mode the designated distance W when the distance is an increment perhaps as small as {fraction (1/600)} inch. Moving the recording media such a small distance requires precision media drive rolls, gears, encoders and motors, which add to the cost and complexity of a fluid ejecting system. Moreover, the flexible qualities of recording media render recording media susceptible to positioning variations that are difficult to predict or compensate for, even in a fluid ejecting system that uses high precision elements. A stepper motor could also be used to perform the same dual motions. However, the same or similar problems often occur in stepper motor systems.
Alternatively, some known fluid ejecting systems use a ball and screw carriage advance mechanism, as opposed to the recording media advance mechanism discussed above. The ball and screw carriage advance mechanism is used with a high degree stepping motor that incrementally moves the fluid ejectors when the carriage has completed placing a swath of fluid upon a receiving media. In such a system, the carriage is moved along support rails by operating the ball and screw, to scan the carriage across the receiving medium. The receiving medium remains stationary thoughout the fluid ejecting process. Thus, all the movements in this ball and screw type printing system are by the carriage and fluid ejectors.
A more recent trend among fluid ejecting systems is to use the same general configurations as discussed above, but to increase the number of ejecting nozzles on the fluid ejector while using the same fluid ejector dimensions. The increase in fluid-ejecting nozzles results in a resolution as high as 600 dots per inch (dpi) versus the standard 300 dpi resolution used in earlier fluid ejecting systems. However, the increased number of fluid-ejecting nozzles is not easily achieved. In particular, the precision required for manufacturing fluid-ejecting nozzles has become increasingly more difficult to attain, since an increased number of nozzles is required to provide up to 600 dpi resolution on the same sized fluid-ejector that may have originally provided only enough nozzles for 300 dpi resolution. Thus, the nozzles necessarily become smaller and more difficult to make.
The above-described prior fluid ejecting systems provide variations of the dual motions along the advance direction needed by the carriage and its fluid ejectors relative to the receiving medium. The servo-motor systems provide movements quickly, but not necessarily accurately. The ball and screw systems provide accuracy but not quickness. Systems increasing the fluid ejecting nozzles on a standard dimensioned fluid ejector result in excess manufacturing and replacement costs.
Accordingly, a need exists for a fluid ejecting system providing a quick, accurate and inexpensive manner of achieving the necessary dual motions of the carriage and its fluid ejector relative to a receiving medium.
In various exemplary embodiments of the fluid ejecting system and methods of this invention, a fluid ejector and carriage are mounted within an interposer frame that is movable along support rails. A separate paper advance mechanism advances the receiving medium a designated distance when a swath is completed. In operation, the receiving medium advances to an initial position for receiving fluid from the fluid ejector, where the fluid ejector is in a first position within the interposer frame. The fluid ejector is biased against a first set of surfaces in the first position by a biasing element. This tends to ensure the fluid is consistently and accurately placed upon the receiving medium as droplets of fluid are ejected from the fluid ejector located in the first position as printing information upon the receiving medium. A spring, for example, may be used as the biasing element. With the fluid ejector in the first position, the carriage travels across the receiving medium, depositing droplets of fluid onto the receiving medium in a swath.
Upon completion of that swath, a position actuator, for example, is energized to urge the fluid ejector to a second position, where the fluid ejector is located against a second set of surfaces. In the second position, the fluid ejector ejects a second swath upon the receiving medium. Thus, whenever the fluid ejector is placed in the second position, the accuracy of placing fluid upon the receiving medium that is achieved is similar to the accuracy achieved by biasing the fluid ejector to the first position. The fluid placement accuracy is achieved regardless of the number, or direction, of swaths being ejected due to consistently placing the fluid ejector against the first and second sets of surfaces corresponding to the first and second positions, respectively.
After a pair of first and second swaths are completed, the receiving medium is advanced to a next position to perform another swath, or pair of swaths, as desired. Thus, the advancing of the receiving medium is easily co-ordinated with the completion of a swath. Moreover, the incremental movement of the fluid-ejector is easily and quickly performed to either of the first and second positions.
Sensors may be used to detect the positioning of the fluid ejector relative to the receiving media, or to provide feedback to a processing system, if, for example, variations in swath widths are desired or other positional information is needed to cause the position actuator to operate and move the fluid ejector to/from either of a first or second position, or to any other fractional part of the distance between either of the first or second positions. After completion of the desired swath or set of swaths, the receiving medium is advanced to place an additional swath or set of swaths of fluid upon the receiving medium as desired.
Alternatively, a fixed fluid ejector may be used in conjunction with an adjustable fluid ejector to place fluid upon a recording medium, wherein a sensor detects the alignment necessary for the adjustable fluid ejector to place fluid in an appropriate location upon the recording medium relative to the fluid placed upon the recording medium by the fixed fluid ejector. The sensor may be, for example, a position sensor using position sensing diodes, such as the position sensor made by Hammamatsu Inc., Japan. Many other sensor types can also be used; such as laser micrometers, or eddy current position sensors, for example.
Upon detection of the necessary alignment adjustment distance, at least one position actuator is energized to move the adjustable fluid ejector the necessary alignment distance to place fluid upon the recording medium in a swath subsequent to the swath of fluid placed upon the recording medium by the fixed fluid ejector. Similarly, as above, the receiving medium is advanced after completion of the swath or set of swaths of fluid upon the receiving medium, as desired.
In various exemplary embodiments, the system and methods according to this invention provides a sequence of synchronized dual motions that are easily performed and are accurately repeatable, while providing a relatively quick fluid ejection process. Moreover, this invention uses structures that are inexpensive to produce, maintain or replace.
These and other features and advantages of this invention are described in, or are apparent from, the detailed description of various exemplary embodiments of the systems and methods according to this invention.

Methods and apparatus providing dual advance of a fluid ejector system relative to a receiving member


Multiple rib fractures in trauma patients are associated with significant morbidity and mortality. Delayed morbidity for patients with rib fractures is often a result of hypoventilation leading to atelectasis, pneumonia and respiratory failure. Pain management was first recognized as an important factor in preventing complications in these patients. Later, management of the respiratory system became more widely recognized as a major factor in, patients' care. It is now known that patients with multiple rib fractures benefit most from adequate pain control, rapid mobilization, and meticulous respiratory care to prevent complications. A rib fracture score and protocol based on a synthesis of the existing literature is developed. The protocol is directed to decisions about rapid mobilization, respiratory support, and pain management interventions to decrease the length of patients' stay in intensive care units.

1. Field of the Invention
The present invention relates to a scoring system for evaluating rib fracture trauma patients and a related protocol for utilizing the scoring system to make decisions on patient treatment.
2. Brief Description of the Related Art
Rib fractures, which account for more than half of thoracic injuries due to nonpenetrating trauma, are the most common blunt chest injury in adults. Motor vehicle crashes are the most common mechanism [1]. Significant morbidity and mortality that occur soon after multiple rib fractures are related to the underlying visceral injury, such as the degree of pulmonary contusion, the presence of hemopneumonthoraces, or injury of the aorta [2]. Other complications that can occur include hemorrhage, flail chest, atelectasis, pneumonia, respiratory failure, and death [1, 3].
Although head injury is the most common cause of death due to traumatic injury, thoracic trauma accounts for 25% of such deaths [2, 4]. Ziegler and Argarwal [4] found that of 7,147 patients admitted to a trauma center, 711 (10%) had rib fractures. Only 6% of the 7,147 patients had isolated rib fractures; therefore, 4% (289 patients) had multiple rib fractures. Their study [4] indicated patients with 1 or 2 rib fractures had a 5% mortality rate, whereas patients with 7 or more fractures, had a 29% mortality rate. Although the study did not indicate the percentage of patients with 7 or more fractured ribs, potentially 83 (29%) of the 286 patients with multiple rib fractures could have died of their injuries. Ziegler and Argarwal concluded that rib fractures were an indicator of severity of injury.
The research leading to epidural analgesia as a standard of care for pain management for patients with multiple rib fractures suggested that the respiratory system has having a major impact on patients' recovery. During normal respiration, the rib heads rotate on their vertebral articulations while leaving the vertebral column stationary; thus the sternal ends of the ribs rise and fall while the vertebral ends remain fixed. Muscular contraction elevates only the sternal ends of the ribs, causing a mechanical motion that moves the sternal ends of the ribs up and away from the vertebral column. This action increases the anterioposterior distance between the sternum and the vertebrae and enlarges the thoracic cavity volume. This simultaneous action causes a 2-dimensional enlargement by the combined effect of the 2 movements.
The external and parasternal intercostal muscles elevate the ribs, resulting in inspiration. With the relaxation of these muscles, the ribs return to their original position, a change that decreases lung volume. Changes in thoracic pressure provide the basis for generating pressure gradients necessary for air movement into and out of the lungs. The process of breathing requires the use of both bony structures and accessory muscles. Broken ribs, particularly on both sides of the vertebrae, dramatically reduce this dual-action chest movement and thus reduce the volume of air into and out of the lung [5].
Lung capacity and volume also change with the position of the body, decreasing when a person lies down and increasing when a person stands [6]. While a person is lying down, the abdominal contents push upward against the diaphragm, causing a decrease in the expansion of the lungs. Therefore, patients on bed rest have decreased pulmonary excursion.
Rib fractures can compromise ventilation by at least 3 mechanisms: (1) pain from rib fractures can cause splinting, subsequently resulting in atelectasis and pneumonia; (2) multiple rib fractures may cause flail chest which interferes with normal costovertebral and diaphragmatic muscle excursion and results in ventilatory insufficiency; and (3) these broken ribs can become penetrating objects that cause a hemothorax or a pneumothorax. The middle ribs (ribs 4 through 9) are the most commonly injured because the structurally weakest point of the rib cage is the posterior angle [7, 8]. Lung-related morbidity of patients with multiple rib fractures ranges from 13% to 69% [2].
A fracture of the first rib is considered to be a hallmark of severe trauma. The amount of force required to fracture the first rib is tremendous and should alert healthcare providers to the possibility of other injuries, such as aortic tears, cardiac injuries, or traumatic injury of the subclavian artery and brachial plexus. Patients with a fracture of the first rib also may be at high risk for late-developing injuries and complications [9, 10]. Patients with this injury should be monitored closely and complications of the injury should be anticipated.
Recognizing the mechanisms that may compromise adequate ventilation is important when managing patients with multiple rib fractures. Inadequate ventilation results from mechanical instability and subsequent splinting of the involved side of the chest, which is unavoidable because of pain [8]. Atelectasis is characterized by collapse of lung tissue on itself, which prevents the exchange of carbon dioxide and oxygen. The loss of this functional lung tissue often results in an increase in heart rate, blood pressure, and respiratory rate. The secretions then become trapped in the collapsed lung tissue. These retained secretions support the growth of bacteria, a situation that leads to stasis pneumonia, respiratory failure and acute respiratory distress syndrome (ARDS) in critically ill patients [6]. Patients with blunt trauma should be considered at risk for secondary complications, even those with favorable trauma Scores or injury severity scores [11].
In patients with blunt chest trauma and rib or sternal fractures, pain promotes splinting and is a major factor contributing to the need for intubation. Pain associated with rib fractures can prevent proper ventilation and coughing, leading to atelectasis, retained secretions and pneumonia [12]. Durable and satisfactory analgesia can prevent atelectasis, which may result in pneumonia. Nosocomial pneumonia can be prevented in these patients by use of prevention strategies, such as early fixation of fractures, rapid mobilization, and adequate pain management [13]. Gabrem et al. [2] attribute atelectasis to increased pulmonary shunting leading to hypoxemia, which may predispose patients to respiratory failure. See FIG. 1.
As a result of nearly thirty years' research in ways to prevent death and minimize complications, from multiple rib fractures, clinical management of these patients has been the key to improving outcomes. Three patient management practices have proved significance in influencing outcomes and preventing complications in patients coming to emergency trauma centers with chest trauma: rapid mobilization, respiratory support, and proper pain management [8, 14-16].
Rapid mobilization is a key factor in successfully preventing hypoventilation and atelectasis with retained secretions, which could result in pneumonia, respiratory failure and ARDS. In a study of patients with ARDS, oscillation therapy provided by a kinetic bed was compared with conventional supine positioning. The patients who had oscillation therapy had significant improvement in lung function without hemodynamic compromise. Continuous body positioning, achieved using such methods as air therapy, prone ventilation, and oscillation might be a promising treatment in ARDS. As does prone ventilation, oscillation therapy provides a larger surface of non-dependent lung sections, a situation that promotes redistribution of blood and allows lung areas previously not being ventilated to be perfused and ventilated [17, pp188-213].
Patients with bilateral rib fractures have an increased risk for complications associated with the basic nursing care that is delivered. For example, each turn or re-positioning maneuver of a patient with bilateral rib fractures places the patient at risk of receiving further trauma. The pieces of rib that have been broken may re-locate to new tissue, thus exacerbating the previous injury. Therefore, it seems reasonable to create a method to determine which patients are in the highest risk group and to provide care that minimizes the risk of complications or exacerbation of injury.
The overall goals of mechanical ventilation for patients with multiple rib fractures are to support the respiratory system while the ribs heal and to prevent complications. If patients can be mobilized, they should be encouraged to move around to maintain homeostasis in their lungs. Although mechanical ventilation may be required as supportive therapy, the prevalence of complications increases with the use of invasive therapy, and the potential for complications such as pneumonia also increases [13, 15].
Incentive spirometry therapy is a valuable tool in postoperative patients. It can also be successful with patients with multiple rib fractures. However, the patients experience significant pain with increased expiratory volumes, so adequate pain control is paramount to the success of this conservative treatment.
If mechanical ventilation is required, decisions about the mode of ventilation become important. Because ARDS is an oxygenation problem, modes that support the exchange of oxygen at the cellular level are indicated. Assist-control or volume-control mode ventilation is used for patients who have a weak respiratory effort, such as patients who are hypoventilating because of multiple rib fractures. This mode is a comfortable one that provides complete mechanical support, but it is not a weaning mode. Pressure-control ventilation has the advantage of limiting pressure, therefore it decreases the risk of barotraumas, but it does not guarantee a baseline tidal volume [17]. Pressure-control ventilation may become increasingly popular as a result of the first major advancement in ARDS in more than 30 years, made in 1999. Investigators [18] found that smaller ventilator breaths or a decrease in the tidal volume setting on the ventilator may reduce mortality in patients with ARDS.
A more aggressive mode of ventilation is pressure-regulated volume control, which adjusts the flow rate of the delivered oxygen to deliver the set tidal volume at or below the set maximum pressure. This mode is the preferred mode for patients with high airway pressures. Pressure-regulated volume control ventilation produces a guaranteed tidal volume but minimizes barotrauma [19]. The ventilator computer calculates compliance at predetermined intervals and adjusts the flow rate of the gas delivered as the patient's lung compliance changes [20].
Results of studies using inverse ratio ventilation have been reported since the 1980s [21-23]. This mode of ventilation is delivered 1 of 2 ways: (1) volume-cycled ventilation with an end-inspiratory pause, or with a slow or decelerating inspiratory flow; or (2) pressure-controlled ventilation applied with a long inspiratory time. Use of inverse ratio ventilation requires that the patient be sedated to prevent fighting the ventilator. This mode of ventilation can cause excessive gas trapping, and close monitoring is required to determine if any adverse hemodynamic effects occur [24].
Although some of the emergent modes of ventilation are experimental, or the equipment may not be readily available in all community hospitals, the modes should be included in any protocol designed to improve patients' outcomes and avoid complications associated with injuries sustained from trauma. These modes include high-frequency jet ventilation, combined high-frequency ventilation; high-frequency percussive ventilation; use of nitric oxide combined with high-frequency jet ventilation, liquid-assisted ventilation, and extracorporeal membrane oxygenation.
High-frequency jet ventilation can be delivered by using high respiratory rates (>60/min) to deliver small tidal volumes from a gas source of high pressure through a small-bore cannula. Combined high-frequency ventilation has been used when treatment with high-frequency jet ventilation is not successful [25]. High frequency percussive ventilation combines the delivery system of jet ventilation and the changes in lung volume of conventional ventilation [26, 27].
Use of nitric oxide combined with high-frequency jet ventilation is well established in neonatal intensive care. Only recently have case reports describing the outcomes of this therapy in adults been published. Campbell et al. [28] reported the successful simultaneous use of nitric oxide and high-frequency jet ventilation in a patient with ARDS with co-existing large bilateral bronchopleural fistulas.
Liquid-assisted ventilation offers an alternative ventilation strategy for supporting life during severe respiratory failure associated with ARDS. This technology is a simple process where inert perfluorochemical fluids are substituted for nitrogen as a medium for gas exchange. Use of these fluids reduces the surface tension in the lung that is created by the interface of gas and tissue. The perfluorochemical fluid recruits atelectatic lung, thereby increasing lung compliance and the area of gas exchange. The effect is to minimize barotrauma [27].
Extracorporeal membrane oxygenation is not a new therapy, but may be considered in an emergent situation. Unfortunately, if the facility providing care for the patient does not have extracorporeal membrane oxygenation, patients may have to be transferred to a facility with a cardiothoracic unit that has the equipment and has staff with expertise in the use of extracorporeal membrane oxygenation [24]. The transfer ideally would occur before the patient deteriorates.
The best outcomes in the care of patients with multiple rib fractures are associated with appropriate management of pain [29-32]. Although the exact mechanism is still being studied, pain management is an important factor in preventing complications in these patients. Epidural analgesia is becoming a standard of care [7].
In a randomized, experimental, prospective study of 100 patients requiring mechanical ventilation because of multiple rib fractures, Dittman et al. [28] concluded that effective analgesia led to an increase in the midposition tidal volume and opening of more alveoli. The control group was treated with mechanical ventilation, whereas-the experimental group was allowed to breathe spontaneously with thoracic epidural analgesia for pain management. The specific outcome measures were functional residual capacity, dynamic lung compliance, vital capacity, airway resistance and PaO2. The experimental group experienced a uniform rise in dynamic lung compliance, vital capacity, and functional residual capacity; a reduction in airway resistance and an increase in PaO2(P<0.001). The control group had an average stay in the intensive care unit of 9.8 days, compared with 4.5 days for the experimental group. Overall, epidural analgesia encouraged a favorable outcome because it enabled patients to cough effectively.
O'Kelly & Garry [29] concluded that pain from fractured ribs causes a reduction in respiratory excursion which increases the ventilation-perfusion mismatch and is the principal problem in a patient with fractured ribs. In their case report, a patient treated with nerve blocks using an intercostal injection with the aid of Tuohy needle experienced total pain relief for 8 hours. The catheter provided a method for continuous delivery of an analgesic agent across several intercostal segments of the thorax. When used for a few hours, epidural anesthetics were extremely effective in controlling pain and in enabling patients to participate in aggressive pulmonary toilet routines [9].
Abouhatem et al. [30] hypothesized that efficient pain relief with continuous thoracic epidural analgesia allowed good physiotherapy management without central sedation and impairment of the cough reflex, thus preventing pulmonary atelectasis and infection. Their hypothesis was supported in a sample of 19 patients with an average of 5 rib fractures. Worthley [31] also reported that pain relief with epidural analgesia was dramatic and was not associated with sedation. During a 6-year period, 161 patients with chest trauma were treated with thoracic epidural analgesia induced by using bupivacaine 0.5% with adrenaline 1/200000. The group had an increase in mean vital capacity from 494 (SD, 300) mL before analgesia to 1130 (SD, 199) mL after analgesia. They concluded that as a result of proper thoracic epidural pain management, patients were more alert and cooperative and thus able to participate in increased activities such as turning, getting up, and physiotherapy.
Rocco et al. [32] compared continuous versus intermittent intrapleural administration of bupivacaine for pain relief in patients with multiple rib fractures. Six patients received doses intermittently, whereas a second group of 3 patients received an initial intrapleural injection of 20 ml of 0.5% bupivacaine and then a continuous infusion of 0.25% or 0.5% bupivacaine at a rate of 5 to 10 mL/hour. Outcome measures for the intermittent dosage group were arterial blood gas pH (P<0.001), PaCO2 (P<0.01) and PaO2 (P<0.001) before and after injection. The outcome measures for the continuous infusion group were peak mean venous blood levels of bupivacaine between 1.1 and 2.38 μg/mL. Adequacy of analgesia was measured as unilateral anesthesia to pinprick from T2 to T10. Although statistical analysis was not presented for between-group differences, Rocco et al. concluded that effective pain relief could be provided with either intermittent or continuous intrapleural analgesia.
More recent research [33-36] supports the earlier findings of the necessity to adequately control pain in patients With multiple rib fractures. Clarke [35] argues that the use of intrapleural catheters for pain relief should be a widespread practice.
Optimally, if rapid mobilization, respiratory support, and pain management were simultaneously used in a systematic method, healthcare providers would be able to define the appropriate level of care for patients with multiple rib fractures. This level of care would encompass preventive care, anticipatory management, and emergent crisis care. Ultimately, delivery of the appropriate level of care delivered immediately would speed up patients' recovery.
Siegal et al. [37] studied the cost of care of patients with multiple trauma. They found that the Injury Severity Score was a poor predictor of the use of resources. Instead, the most common variable that explained more than 80% of the variability in cost was the length of stay. The most common complications involved the respiratory system. Therefore, if the most common complication can be closely managed, the length of stay theoretically should decrease, along with the cost associated with that stay.
The lungs become less elastic or they lose compliance as a result of the normal aging process. The number of alveoli and small blood vessels around the lungs diminishes. The vertebrae in the spine become compressed, causing the disc spaces to be smaller, reducing chest volume. The diaphragm and the intercostal muscles also weaken with age. These changes result in decreased lung expansion. Therefore, the lungs take in less oxygen and exhale less carbon dioxide. Overall lung function is decreased. These anatomical changes alone contribute to a vulnerability to pneumonia and bronchitis [38].
A lower threshold for admission of the elderly with isolated rib fractures may be warranted because of the higher incidence of hypoventilation, hypercapnea, atelectasis, and pneumonia [12]. The age of the patient seems to be pertinent data to include in the development of a protocol for management of patient with multiple rib fractures.
Ziegler & Argarwal [4] studied patients' outcomes after multiple rib fractures. They documented a significant correlation between mortality and increases in the number of ribs fractured. They hypothesized that most patients with multiple rib fractures will have associated injuries and proposed that as the number of rib fractures increases, so will the Injury Severity Score and mortality. Ziegler & Argarwal [4] also predicted that one third of patients will have pulmonary complications, one third will have a hemothorax or pneumothorax, and one third will require transitional or extended care.

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An automated assembly system for assembling a truss from a plurality of truss members and connection plates includes a plurality of rail assemblies, a plurality of trolleys, a plurality of press assemblies, and a control system. The rail assemblies include stationary rail assemblies and moveable rail assemblies. The trolleys are supported by the rail assemblies. The press assemblies are supported by the trolleys. The press assemblies are configured to embed the connection plates into the truss members. The control system is programmed to control the operation of the automated assembly system. An ejector system is configured to remove assembled trusses from the automated assembly system.

Trusses are commonly used in the construction of buildings, such as residential homes and commercial buildings, to provide support to a roof structure. Trusses come in various sizes, shapes, materials, and configurations. Trusses are commonly made of wood. Many truss configurations include a generally triangular outer shape and include a bottom chord, two top chords, and a plurality of web members. The bottom chord is oriented generally horizontal when installed on a building. Each top chord extends from an opposite end of the bottom chord. The joints between the top chords and the bottom chord are commonly referred to as heels. The ends of each top chord, opposite the heel, are connected together at a location referred to as the peak. A plurality of web members are connected in the space formed between the bottom chord and the top chords, often being arranged to form triangular patterns to distribute sheer forces within the truss.
Joints between the top chords, bottom chord, and web members are often connected using a connector plate. The connector plates are typically formed of a metal material and are formed as a rectangular sheet. The connector plate usually includes a plurality of nail-like regions that have been punched from the plate and bent such that they extend generally normal to a primary surface of the plate.
To construct the truss, the various wood members are first cut having the appropriate length and shape. The wood members are then arranged into the desired configuration. Metal connector plates are then placed over each joint and pressed into the wood to secure the members at the joint. A press head can be used to press the plate into the joint.