CA2723292A1 - Gear oil compositions, methods of making and using thereof - Google Patents

Abstract

A gear oil composition is provided. The composition comprises a sufficient amount of an isomerized base oil m a base oil matrix comprising at feast at least a polyalphaolefin for the gear oil composition Io have for the gear oil composition to have an average volume change so. a rubber seal between -10 and +10, a change in shore A hardness between -7 and + 10 when tested with SRE. NBR28 at 100°C., 168 hours per DIN53521I and DIN53505, a viscosity increase of less than 3% per US Steel S-200 oxidation stability test, a precipitation of less than 1% per US Steel S-200 oxidation stability test, a d & Timken OK Load of greater than 60 Ib. The isomerized base oil has consecutive numbers of carbon atoms and less than 10 wt% naphtenic carbon by n-d-M. ïn one embodiment, the sufficient amount of isomerized base oil ranges from 20 to 75 wt. % based on the total weight of the gear oil composition.

Description

99X4917, WO-.A..99'O72O ai.id WO-A- 510 9 5. 'I`he F iselier- l~ropsc.}
synthesis product i.isaiaily comprises hydros arhoias having I to 100, or even more than carbon atoms, and typically includes ParaÃlins, olefins, and oxy'g'enated.
products'.
Fi:~eher ,i,ropseb is a viable process to gene 'ate clean alternative hydrocarbon products, f(104_ There is a need for a gear oil composition c o ntaiiaing alternative hydrocarbon products having, excellent load car'r'ying capacity, high ox..dariv stability, and seal compatibility.

<t? UM I ARY OF THE I.i~lt~'l: N`l`It N

[0051 in one aspect, the invention relates to a gear oil a onlIo?sition comprising: a) a base oil containing ai synelgisti+, mixture of at. least an isomeri`1.ed base oil having consecutive numbers of carbon atoms and less than 10 wt%
naphithc:nÃc ca bo+ a by it-d=- t~'l, and polyalphaole_ in base stock having a kinematic viscosity of ;3 to 1 'Ã? :i~im Ss at. 100 C, and a viscosity index of at least 60 b) (W01 to 0 wt % at le ~t an additive à lected from traction red :Ici:rs, liisp"ersanÃs, viscosity rnodi 'zer: , pour point depressants, antitt?amin g agents, ntioxidants. rust inhibitors, metal pass viato'Srs, extreme pressure agents, friction inodi tiers, and mixtures thcrex&, wherein the i.sunierize l base oil is present in a sufficient amount for the gear oi3 le composition to have an average volume change in, _ rubber seal b tween 40 and + l >
and a charge in shore A hardness between -7 and - 10 when t.stecl with SR:I

at I0s' C., 168 hours per I ~ ro:I ' I erase :I tI I~, In one embodiment, the gear oil co reposition further has a viscosity increase of less than 3% N ,-r Steel S-20ÃI
oxidation stability test, a precipitaticm of less than I c''iz per i .S Steel S_200 oxidation 25 stability to e, and a Timken t }lS Load of Vii, aatà r than 60 II?.

(006] lit another aspect, The invention rebates to a Ãnethod fur improving the oxidative.. stability and seal compatibility properties of a gear oil composition, the method. comprises adding to a base oil matrix comp rising a polyalphaoiefin -#:rom 20 to 75 i 't % abased on the total weight of the gear oil Ã.o-inpositioÃi) of an isome'rized. base .3 ) oil, for the gear oil composition to have an average volume change in a rubber seal between -10 and :} 10, a change in shore A hardness between ..7 and -4-10 w hcn tested with SRE. NBR28 at 100"C', 168 hours per DlN53 ;2I and 0IN53505, and a viscosity increase of less than 3% per US Steell S-20t3 oxidation stabili IN, best.

DESCRIPTION' [0071 The following t :r ? s will be used throughout the specification a id will have the following meanings unless otherwise indic ated.
[008] "Fisch;: =1 ropsch derived" means that the product, fractiom, or feed originates fil n or is p ?c.uce at soil?.e stage by a à ischer-'T'ro sch process. As used herein, "Fischer-T.ropsch base oil" may be uses: interchangeably with "Fl baise oil,"
"F 1130,,, " TL base oil" (GI Ia: gas tcf, l iqu d), or a isc}ter-`a ropsch derived base oii,', a made by 0~~4 ' > refers to a ~? ` 9`1 An ar: [:cI Ixeri;in, "'`c5E?illeri;r.i't'~ ~-iaae 61" rt,.=.~>'s tÃ: I.<asc: #33i t0 isi?al>e'rization of a waxy feed.
( a Ãl. :=~ used herein, a `'r za't 'feed" <?Y prises ~ t e.a t 4 apt` n- ?:ir in . In one cmibodiment, the waxy feee f. coax prises greater than 5 ;=vt ',='0 1I
pival-fins. In a other embodiment, greater than 7:5 wt% a-paraffins. In one e riibodiment, the waxy feed also las ve: low levels of nitrogen and sulp Sur, e.g., less than 25 ppm total S co *in e, nitrogen and sulfur, or ixt other ei à odi Tents :l~ ss '-, 20 I' pm. Examples of L4"ax feeds include slack ,axes. deoi.led slack waxes, refined lbots Nwixy tuil:iricarit Kamm, .ri paraffin waxes, NAO sa es, waxes produced in chemical plant proces :es, deo led petroleum derived s axes, ntieroct sty ll ae waxes.
Fischer-Tropsch ,saxes, and mixtures thereof. In one embodiment, the a y t:aeds have ai pour point 20 of greater than 50'C. . In another embodiment:, greater than 60'C, [Ã 111 " l . nemllatie. viscosity' is a measurement in ruin s of the resistance to flow ofa fluid under gravity, determined by ASTNI D445-06, [012] "Viscosity index" (VI) is an empirical, tunic less number indicating the effect of t l'z~I criatur change on the kinematic viscosity of the oil, The I
igher the VI
25 of an oil, he km&er its tendency to change viscosity with teri teriatur :.
Viscosity index is measured accord41 to ASTM 13 22.7 0-04.

[01 31 Cold-cm nking simulator apparent ti isco;sit ' R TS VIS) is a measurement in nmi ltpaseal seconds, m a.s to measure the viscometric properties of Lubricating base oils t ider low temperature and low sl?ea ÃCCS VIS is dete.rniftled by 3i0 ATM l 5293-0$, 1014 .1 - The boiling, range distribution of base nil, by is determined by simulated distillation (SlMi)IS) according to ASTM I) 052-(4, "Boiling Runge Distribution of Petroleum Distillates in Boiling l .(e from 174 to 700"C by Gas 1'015] "Noack volatility" is defined as the mass of oil., expressed in weigh, %, which is lost when the oil is heated at 2,50 C`. with a constant flow of air drawn through it for (if) min., measured ic:c:ordin to ASTM: D5800-05, Procedure B.
[0161 Brookfield viscosity is used to deter'rnine the internal fluid-friction of a lubricant during cold temperature operation, which can be measured by ASTM I) 291"x3-t4.
[017 " ?Ãacrr iii t'' is a .me surerrrs n s'Ã11~ terriperature at ~ hick ar saxiiple ;rf base oil will begrin to flow under certain carefully controlled conditions, v hich cirri be determined as described in ASTNM 1) 5950-112.
[:0181 ".Auto ignition: temperature" is the temperature at which a fluid will ignite spontaneously .in ConÃact with atr, which can. be determin .d according ic., AS-11M

t 4 101 ` 1 ``Ln"' refers to naltural. to gari.thm ~z i th bars : "e."

[020] "Traction co 1fcient" is an indicator of intrinsic. lubricant properties, expres~i..d as the d3Ãi1iF#hÃi+i1ILss ra:tres of the friction 'rfriction f6rce Find the normal force N, where friction is the m chanical force which resins movement or hinders movement betwe n slici.in i}r ?I1r~rg sun ces. fraction coefficient can be measured with an 1`I MY Traction Measurement System from P S insirugle:.ms, Ltd. , configured with a olislied 19 n-un diameter ball (A , AISI 52100 steel) angled at =223 to a flat 46 i-nin diameter polished disk (SAE :41:51 552100 steel). The steel ball and dish: are independently measured at an average rolling speed of 3 meters per second, a slide to roll ratio of 40 percent, and a load of 20 KeLetons. The roll ratio is defined as the 2a difference in sliding speed lam.;-wen the ball and disk divided the iii an speed of the ball and disk, i.e. roll ratio = s ` peed .l '~pi ~ t `ii Speed =Speed ?l-/2), 10211] ] As used herein, "consecutive numbers of carbon aÃ+ ms " means that the base oil has a. distribution of hydro arhon molecules over a range of carbon number's, with every number of carbon numbers in-between. For example, the ba e oil may have hydrocarbon molecules ranging, from x;22 to C36 or from. ('30 to C60 with every=
carbon number in-between. The hydrocarbon molecules of the base oil differ from each other by consecutive n tubers of carbon :atoms, as a consequence of the Waxy feed also having consecutive numbers of carbon atoms. For ex'rinple, in the Fischer-`frostÃsch IlNydrocarbon synthesis reaction, the source of carbon atoms is CO
and. the hydrocarbon riokeules are built up one carbon atom at a time. Petroleinn deriv waxy .feeds have coIÃSe-'i,:utive nuà lben of Carbon atoms. In Contrast to an oil base. a on poly-alpha-olefit) ('P A()"?, the molecules of an isomerized base oil have a Ã-Ã)ore linear strÃt .tune. comprising a relatively long backbon with short hzmatiches,. The classic textbook description of a PA(O is a sta=-shaped molecule, and in particular tridecane, w Which is illsÃ.strated as three dccane molecules attached at a central point. While a gt:ar-shaped molecule is theoretical, nevertheless PAO mole eÃlle.s have fewer and loi:ieer branches that the hydrocarbon r iolecules that rake Ãap the isomerized Else oil s i.;sÃ:lo se l herein.
[022': ' o ecu es with c cloparaffinic Xuncticonahty' mean an moleculf, That is, or eommnls as one or more stibst:tu .nts, a monoc}'clie or a tI eÃl illÃ.Ã13:icvc.ili=
saturated hydrocarbon group.
10` 1 folectiles with ailrinocy ie is i i ri unctionalit " meant any molecule F that is a mom ocyc ic saturated hydrocarbon group of three to seven ring cala~bons or any molecule that is substituted with a single monocyclic: Saturated hydrocarbon group of three to se en ring carbons.

[0241 =` MoiieetÃles v ith muiltÃcy'clopara'ffinit 'Ãii#it tiCll alit' ia3Ãan any molecule that is a fused ::iiulticyc lÃ.c saturates hydroc&bon Ling group of two or :more fused ( rill S, any molecule that is substituted one or more fused trlÃÃIticyydlic sate Ãted.
hydrocarbon ring groups o b A,,() or more fused rings, or any molecual: that is substituted with more than one monocyclic s iturateÃl hydrocarbon group of three zo Sewn ring carbons.
(0251 Molecules witli, eyelotlaraffutie functionality, molecules with 25 mo.riocycloparaflinic fu ctionality, and m skc:]le..s with 3l ul't.Ãcycloparaffinic functionality are reported as weight percent and am determined by a combination of Field ionization Mass Spectroscopy (FlNMS . HPi,a:4I ' ic?r aromatics, and Proton NMR ti)r olefins, further filly described herein.
[0261 Oxidator 13N measures the response of a lubricating oil iii a simulated sfi application. High valises, or long titries to adsorb one liter of oxygen, indicate good tabilit à xidaÃor BN can. be measured via a Oornte-tylle oxygen absorption apparatus (R. W. l)ornte "Oxidation of Whits!. Oils," Industrial and Engine zin t ;hc:r ii stry, Vol. 2.8, page 26. 19316), under I atmosphere of p'Ãire oxy gen at 3 4 llt It , time to absorb 1000 ml of 0; by l (10 g. of oil is reported. In the Oxidator BN test. 0.8 ml of catalyst is used per 100 grams ofoiL The catalyst. is a.m xtu e of soIubIc metal..
napbUlici aces simulating the average .imm , al analysis of used crankcase oil. The additive package is 80 mill moles of Zinc bi51?+;iy ?ropyl Ãtcl?l?e~??Y
ldithiophosphate per s 100 ;;:rains of oil.

1027] Molecular cl Ã?racteriz.~t csit can he peribÃuied by methods known in t be an, including Field Ionization -`las Spectroscopy (11 MS) and n d-: I
ariaaly'si~ (AST 'I
I) 3238-95 (Re-approved 11.005) zsrith.normaliratioà ), In FIMS, t e base oil is characterized as alk-aÃ?es and molecules with d fT rent. numbers o-unsaturatio.n s. The to aatolecules itzk different numbers of unsaturations may be comprised of cycaoparaaffaas, olefins, and aromatics. If aro-m Itics are present in significant amo mit, they would be identified as 4-wisatnrations. When olefins are. present in significant aÃi5ounts, they Would be identified ix, l -unsaturations. The total of the I --u 5atu. aÃions,

2.-nns, tii'a3=.icros. ..uns -uiations, 4= nsaturations, 5-.unsaturations, and 6-unsatt 'ct ons iS from t e FINS analysis, minus the wt `'u olefins by proton NMR, and minus die wt. %
aromatics by l-lPLC-UV is the total weight percent ofmolecu.les with cyclop aral-f nic functionality. It the aror-natic.s content was tacit measured, it was assumed to be less than 0, . wt % and net included in thQ calculation fit total weight perk ent of molecules with cycioparaÃffinic functionality. The total weight. percent of molecule a with?.
.20 eyeioparaffinic _ mctio nality h s the stun of the ~:>ei ;ht: percent of molecules with rÃ?o?noc clopraainic f inctionaality and the weight percent of tuolecules With multicVcloparafTin.iC fimct:iona lity.

[0281 Molecular w ights are determined by ARN-1 D250 92 Reapproved 2002). The method uses thermoelectric measurement of vapour pressure (WO), In circumstances Where :acre is insufficient sample volume, an alter ative method of ASTM I3~'Sit2 ti l may be used', and where. this has been used it is indicated.
(t?29] Density is determined by AS'l'M 04052-96 (Reapproved 2002). The sample is introduced into an oscillating sample tube apn the change in osE ill atÃa, frequency caused by the c;hang in the mass of the tube:- is used in cor~pnctlon, with yi calibration data. to determine the density, of the aaamplo.
f0301 Wei ;let perc~ to tali f z can Ian d to Ã?lined ?z Prot n-NM aai.a.c?ÃdiÃa tÃÃ
the steps specified herein. In most tests, the olela.ns are conventional oktins, i.e. a distributed mixture of those olefin ty es having hydrogens attached to the double 4i bond carbons such as-al pha, vinyiide.sej cis, trans. and tri-substituwd, with a, detectable a llylic to olefin irate ;ral ratio between l and 21,5. When this ratio exceeds 3, A .Indicates a higher percentage of ti i or tera substituted olefins being prmilt, thus other assumptions known in the asiaKtical art can be made to calct.Ilate the number of double bonds in the sample, A solution of 540% of the sample in deutct'c?chl roform can be prepared, giving a normal proton spectrum of at least 12 ppm pectral width-'etra2~iefhylsilatie (TMS) can be used at, an internal reference statldard.
The instrument used to acquire fife spectrum and. reference the chemical shift has sufficient gain rainge= to acquire a signal without overloading the rcceivetf DC, with a minimum.
1113 signal digitization dynamic range of at least 5+5,000 when a si; de free pulse is applied.
The intensities of the proton signals in the region o: 0.5-i.9 ppm (meth-vi, methylene atndfnethine groups), L9-21 ppnl (allylic) a xd bet 'eels. 5.0-4.5 pp xa Ãolefi aVe ' rer.ka~i i õ s vapor 1 siixg the average molecular weight (e~.\t:ir~wteel by 1xi'eS;ire measured.
osmori' etry by ASTM:1) 250+ 92lre-approved 20021) ofea h dirt llate range paraffin feed, the :Ibl owing can be calculated: (.1) the average molecular formula of the %rtraat,ed a da .atE?nsis, f`'.l the average molecular ff{tsx;aFL3 of taxes olefins., (3) the total integrat intensity (i.e, the Steal o1: all the integral mteiisities). (4) the integral intensity per sample hydrogen (i.e, the total integral inteà sit4> divided by the number of hydrogens in he. formula; (5) the number of olet:in hydrogens Ox. tbe o1offin, integral divided, by the. integral per hydrogesi); (6) the number of double bonds (i.e.
thy: olefin hydro en laxisitiplied by, the hydrogens iri the olefin f rrlxtsl:? divided -lbyb 2); and (7;j the weight percent olefins (i.e:.. 100 multiplied by the number of double bonds multiplied by the number' of hydrogens in a typical olefin viol ecule divided by the number of hydrogens in a typical distillate range paraffin red molecilei, This ProtoÃt'N_MIZ
procedure to calculate the olefin content of the sample w corks best when the oiefmn content is low, e.g,. less thar about 15 weight percent.

0)1,1 Weight percent anomalies in one embodiment can be measured by HPLC=-U V. 121 one e2i bodim i>t, filet to t IS G(3riSlFet =d usin a.
ilewlett l ac ai'd 1 ` t Se rics Quater arS' Gradient 1-li; h Pen' emance Liquid Chromatography (1 111.1,C) to system, coupled with a HP 1050 Diode-Array UV Nis detector interfaced to Lan l-i-1 Che:rix anon. leleixt tai atii n of the individual aromatic classes in the highly saturated base oil can he made an the hasi ; of the UV spectral patter m d the elution t.irr te. The amino eolimin used for this analysis differentiates aromatic molecules largely on the basis of their ring- nurn 5er (or double-bond munber). Thus, the Single ring aroynatic.
Containing molecules elute first, followed by the polycy'chc aromatics in order of incrc ising double bond riwnbe.r per moleculle. For aromatics with. similar double bond character, those with only alkyl ubstit.utic,tt on the ring eluto sooner 11.i in those with naphthenic substitution. Unequivocal identification, of the various base à it aromatic hydrocarbons from their U absorbance spectra can be accomplished recognizing that their peak electronic transitions are all :.d-shifted relative to the pure model compound analogs to a degree dependent on the amount of alkyl .mid naphthenic substtt~i Ian on the ring ystem. (cant: scat of le. el..lÃlag aroma tic compounds can be made by integrating chromatograms made from wavelengths optimized for each general class of compounds over the appropriate retention time window for that rare matic.. f a tet tieFtt bi to ~~ inclot irrt3.its 'fiir e ic:l't rom tic c lass can be cie termined b manually e vali.iat.ing the individual a >sc rhance spectra of eluting compounds at different times and assigning them to the appropriate a omatic class based On their qualitative similarity to model compound also rtion spectra.
1tl:?'' Weight percent aromatic carbon "Ca"' , weight percent naphthen -ic carbon ("Ca" and w eis ht percent paraffinic carbon `C;p"t in one embodiment can be measured by ASIM D3238-95 (Reapproved 2005) .~i.th normalization. ASTNI
1)3238-93 (Reapproved 2005) is the Standard Test Method ihhr Calcu.laÃion of C;r'bon Distribution and Structural Group 1An ly sis of Petroleum Oils by then-4.d-M
Method.
This method a fir "e?lc fin .tree:" .feedstocks, i.e., having an olefin content of 2 wt% or less. The normalization process consists of the fo lowing: A) If the Ca value I,, less than zero. Ca is set to zero, M d Cn and ('p are i 3cr'easecl proportionally so that the sum is 100%, BB) If the C11 Value is less than zero, Cn is set to zero, and Ca and C"p are, increased proportionally so that the sum is 100%i and C) If both Ca and Ca are less than zero, Cu and Ca are set to zero, and C'p is set to 100%, 10331 H ITC-UN Calibration. In one embodiment, HP C'-1.=V can be used fear identifying classes of aromatic compounds even it very low. levels- e.g., multi-ring aromatres tv mcally absorb 10 to 200 times more strongly, than single-ring aronnati.cs.
Alkyl-subs,, itution affi:cts absorption. by 20%. Integration limits for f e co-eluting I
ring and 2-ring aromatics at 27 am can be made by tl e perpendic.rilar drop method.
Wavelen ;th dependent response, factors for each general aromatic class can 1 ; first determined by constructing. Beer's Lacy plots from pure model compound mixtures based on the nearest Spectral peak absorhances to the substituted aromatic analogs.
Weig,l'a percent concentrations of ar rnarics can h calculated by. assuming that e he at: 'Lra g molecular %,'einht for each aromatic class was approximately equal to the average molecular Weight for the w ?ole base oil sample.
1034) NIMR arÃalysis. In one,. embrtodim. nt, the =e ght percent of all molecules with at least one aromatic furiction in the purified. mono-aromatic standard can be confirmed via long duration carbon 13 N NI-R. analysis. 'Be, NMR ivsults s;
<n? be translated from % aromatic carbon to t? a ti?niatic molecules Iwo be consistent with HPLC-i=UV and D 2007) knowing that 95-99% of the aromatics in h= ghly saturated to base oils are single-ring aromatics. In a iother test. to i1 ura l F
.iT?easur+~. kw-- levels of al molecules With at least one aromatic function by NMR, the standard l) 5292..99 (Reapproved 20Ã"4) razed od can be modified to give a minimum carbon sensitivity of 500:1 (by A S7 M standard practice I :it t ac>iÃh a 15-hour duration run on a : lk with a Ist 121 min IclaldrrFac trrc?t?E. At ibaa PC int gratiÃ?rt :,ofware can be 15 used to deists: the shape of the. baseline and consistently integrate.
[035 I xtent of ?ranehiaiu r .fers to the number of alkyl branches in hydrocarbons. Branching and branching position can be determined usin ;
cart?ori-13 (a- Ã::) N MR according to the Ulowinl .nine-step prÃ.ices.s 1) Identify the CH i branch cetriter:s and. the Cl=ip branch termination points using the DEPT Pu .se sequence 20 (Do drell, DA".; .; D. TIleg 1.R. Hernial(, J=r rrra o>f. afagnati ResorrÃm<:e 1982, 48, 13ff.). 2) Verily the absence of carbons initiating multiple branches, (quz cri a:r;
Spool rzt, < i~zrrrzcz< a ,~
carbons) using the APT pulse sequence Watt. St.; j, N, Al:fct rnÃ.ri Resonance 1982, 46, ?3 ft.), 3) Assign the various branch carbon.
resonances to specific branch po liti?r? and lengths using tabulated and calculated values known in the art (Lindeman, L. P., Journal of #rualitatlve Analytical Che nistr3' 43, 1971 1245fl', Ne:i fei, D., et.aal, Fuel, 60, 1981, 3+ti 7 ft). 4) Estimate relafa'e branching density at di11 :rent carbon positions by comparing the integrated intensity of the specific: carbon of the methyl/.alkyl group to f e intensity of a carbon (which is equal to total integral/number of carbons per molecule in the mixtu e). For 30 the 2-methyl branch, where lx?th the terminal and the branch methyl occur at (tae same resonance position, the intensity is divided by two bete?re estimating the branching em,4iy>. If the 4-ri?.ethyl branch fraction is calculated and. tabulated, its contribution to 1l? 4 rri~tl?sis is Eal?tract d to a ÃsiÃl ci?alai le c?tinting. S) Cal ulaate the average carbon r.Ã}u h :r. The average carbon number is determined by dividing the molecular of the sample by 14 (the fort.nula, weight of CH:~). 6l the number of branches p ::r molecule is the sum of the bra ?ches than in s p 4. 7) `!'. he number of a.lkyI branches per 100 carbon atoms C lUlated from the number of branches per molecule (step times 100 r average carbon number. 8) Estimate Branching Index (M) by ' H NMR
Analysis, which is presented as percentage of methyl hydrogen (cherÃr.ic-l shift range 0,6- 1,05 I.?pmÃ) among total h rrircgen as estimated by NMR, in the liquid hydrocarbon composition. 9) Estimate Branching proximity (Bp) by ÃT NMR, N hich is presented .Is percentage of recurring methylene carbons -- which are four or more carbons away i from the and group or a branch (represented by a NMR signal at 29 9 ppm) among total carbons as es in?ated by NMR in t xe liquid hydrocarbon comps siuion.
The measurements can be performed using any Fourier 1 ransforrn NMR spectrometer.

:.g one .havÃng a magnet of 7.0 T or greater'. After verification by Ma is Spe :.tromet:y, UV or an NMR survey that aromatic carbons are absent, the spectral width for tl.c!C
AMR studies can be limited to the saturated carbon re{ ion, 0-80 ppm vs. TI
(tctraarrethy-l.s,Ãlane.).. Solutions of 25.-:SO v31, % in chlfmform--dl are exciÃed by 30 degrees poises followed by a 1. .3 seconds we.) acquisition time, In order to minimize non-lrniform inter city data, the broadband proton inverse-gated decoupling is used during a 6 sec. delay prrior to the excitation pulse and on miring acquÃsÃtion. Samples are doped withØ03 tea 0.Ã 5 i: r Ãacaei; 4_Ãris , c ty l.rcctc?.alai ~ c:
ir;~r~?ittÃxr (11th as a relaxation agent to ensure Uli intensities :axe observed. The DEPT and A19' sequences can be carried out according to literature descriptions with minor deviations described in the fir,Ãriau or Broker operating manuals. DEPT is l)isto tionless Enhancement by Polarization Trans.ter.. The DEPT 45 sequence gives a. signal all i5 carbons bonded to protons. Ã-.IEP'I' 90 shows CH carbons ooi . DEPT 135 shows CH
and I1-1 , tip and Cf 1, 180 de roes out of phase (downÃ). APT is attached proton test, known in the an. It allows all carbons to be seen, but lf~ :l i à id 0-1; are up, then luatemaries and 0H2 art-. down. The bra. ching properties of the sample can be le err:nin.ed by C NIR using the assumption in the calculations that the entire .1 sample was rice-paraffinic. The onsa.turates content may be measured Easing Field Ionization Mass Spectroscopy, (ElMS).
[0361 The gear oil composition Comprise; :11.001 to .30 wt% of optional additives in a base oil matrix- In one embodiment, the base oil matrix is a blend of Iwo components", an sonie:rized base oil component A and a base component U, comprising at least a polyal hao efin base ?il, with the amount of the isomeriud base oil being `=u ' dicier t for the gear oil composition to have the di fired load carrying capacity, high o_xi l ative Stability, and seal compatibility properties, 037 f q i j r zed_Base Oil: In one embodiment, component A of the base oil matrix comprises at least an isomer"ized base oil (or blends of isomeri red base oils) w' hich the product itself, its friction, or feed originates from or is produced at some stage by soinerization of a waxy feed from a Fischer-Tropsch process (1"ischer Fr'opsa l1 derived base oils"), In another embodiment, the base oil t3 comprises at least an somer1ed bare: oil made from a sub>ta tially pa afnie wax fief: ("w axy f ..d" In a third embodiment, the .isoinierized. base oil comprises mixtures of products, matk from a substantially paraffinic wax f ;ed as ,'sell as products made from. a waxy feed from a Fisclier"-Tropsch process.
(0381 l i:ictie r mp.~, a derived base oils are disclosed in a number of patent `S publications, including for example .S. Pat. No,,,. 60,03110 l, Ã 090989, and $165949, and US Patent Publication" o. Ilf 2004180796 7$A1,'13 S 2 00501335 409, U82006089337. The Fischer=-1 ropseh process is a catalyzed chemical reaction in which carbon monoxide and hydrogen are conv or ted into liquid hy-diocarbons of varic)".us forms including, a light reaction ;pro duo and a waxy reaction product, with 2Ã} boll being $F?l?t3"1t:a1lsr paraffinic.
[0391 In one embodiment the isomerized base oil has consecutive numbers of carbon atoms and has less than 2.5 w t% iiaphthen.ic carbon by r -d-M. with nornmaliza ion. In another embodiment, the amount. of naplhthenic c<arbk'~in.
is less than l0%8'1-%. In yet another embodiment the isomerized base oil made from a ~,saxy fled has a kinematic, viscosity at ItitY'C between 3..5 and ~.5 rln'r s.
[040 In one embodi i"re.nt, the isomerized base. oil is made by a process iri.

w hich the hydroisomeri cation deb3axing.,. is pert61ned at condition;, sufficient for the base oil to have.- <) a weight percent of all molecules with at least one aromatic functionality less tl1,111 0.30; h) a Weight percent of all molecules s th at least one 30 :yclopaara"f"l nic function"al"ity greater than 10; c) a ratio of weight Percent molecule's' s itu rt?tiif,f yclf:}fifrra fi?ic talnctf1n<ality to weigh. percent -i iolecules with ri3:iltic ciopareat ria; functionality greater; than `t} and d) a viscosity index greater than 28 x La (Kinematic viscosity at 'I 0(,);'C,") 4 90.
II

[041 In another ernbodi.ment, the isome r ized base oil is made from a process in Which the highly paraffinic vs<a>. is hydroisomerire l Lasing a shape selective intermediate pore size molecular sieve comprising a noble metal hydrogenation component, and tinder conditions of 600 -- 750"FF. (315 - 399"C.) In the process, the conditions: for hydroisomerization are controlled such that the conversion of the inn Is bo.iiii g above 70VF (37in the wax..feed to compounds boiling below 700"F (37 1"C.) is maintain .d between 10 Wt % and 50 w t %. A
resulting isome, ized base oil hMs a kinematic viscosity of b tween 1.0 and. >.5 caxrax' s at and a Noack volatility of less than 50 weight 'is. The baase oil comprises greater than Ã0 3 weight% molecules With ef:c lral?aa,raffiiaar: taaarctio i:al à and. leas than 0.:30 weight percent aromatics, [042] In one embodiment the isomerized base oil has a Noack volatility less than air. artxount calculated by tl= e following quation: 1000 (Kinematic ~~
iscosity at.
In another embodiment, he isomerized base oil has a, Noack volatility )5 less than an amount calculated by the f xllow.ing equation: 9,00 x (Kir ematic Viscosity at IIIi? C.l ...a In a third ei bodimeart. the isorneriz. d base oil has a Kinematic Viscosity at 1001'x`. of ., 1.808 mm'/, and a back volatility. less than an amorist calculated by the following equation: 1.286' 20 (kvlÃIt}"1 `.~ 4, 551.
ttt~,r; Where kv 100 is the- kinematic 'iscosity cat 1t 0 C. in a ourth s;a'r bodizrae t, tiac: isomerire t >t~ base oil has a kinematic viscosity at 10à "C. of less than 4.0 :ram'/s, and a wt% Noack volatility between 0 and 100. Ina fifth embodiment, the, isonxerizeed base oil has a kinematic. viscosity between 1.5 and 4,0 mm2 s and a caz ck. volfat lià less than the Noack volatility calculated by the :following equation: I6ÃE - 40 (K.inematic.
Viscosity at 1 OTC).

21 [043" In one embodiment, the isomerized base oil has a kinematic viscosity at 100'(-'. in the, range of 2.4 and 3.8 mm2i's and a aNoack volatility less than an amount defined by the equation: 900 x (K.ineiriat.ic, Viscosity at I, 00 C.) -15i.
For kinematic viscosities in the. ratio of 2.4 and IS sirs=xa:%s, the. equation:
90") x (Kinematic Viscosity at 101`'C) z.s ..1 5) prov ides a low; r Noack volatility than tile 3tt equation: 160- 40 (;Kinematic Viscosity at 100 C.;t 044j in one erribodin ent., the isomerized base oil is made from a process in which the highly paraffinic v a.,x is hycIroia`someri:zed under conditions for the base oil to have a kinematic viscosity as l00 OUT, of 3 6 to 4,'2. nant'~s, a viscosity index of cg. eater than i30. a wt"/6 Noack volatility less than 12, a pour point of less [04.5 in one embodiment. the isa?arieri red base toil has an aniline point., in degree F, greater than 200 and less à pan or equal to an amount defined by the equation: 36 x Ln(l` .inematic Viscosity at I00 C. ;21 nun""s) ,- '200, 0461 in one embodimea t., the isomerized base oil has an auto-ignition temperature (All greater tl:ian the l :l' defined by the equation: AlT in C. I
.6 x (Kinematic Viscosity at 40'C., in rrara "r` + 300. In as second. embodiment, the base oil as an AU' of greater than 329 "C, and a viscosity index greater than 28 x 1. a Ã<) (Kinematic Viscosity at 100" C, in rn-na'r's) -t-- 10(), ('0471 In one embodiment, the isomerized base oil' has a relatively low traction coefficient, specifically, its (r action coefficient is less than an amount calculated by the equation. traction coeffic$ent `0.009 x, L n (kinematic vis osity in mm `s) -0.001, wherein the kinematic v'isco'sity in the equation is the kinematic iscos'ity dwin g the traction coefficient meaisurement and is between 2 and 50 In one e ianbodiÃiientt, the isoi:iterized base oil has a. traction coefficient of less than 0,023 (or less than 0,021) when measured at a kinematic viscosity of 15 n m`/s and at a slide to rà it ratio of 40%. in another embodiment the isomerized. base oil has a traction eoz.thcient of less than 0,017 when m e a s u r e d at a kinematic viscosity of I i mritrs and 20 at a slide to roll ratio of 40%, In another e mbod.iment the isomerized base oil has a viscosity index greater than 150 and a traction coefficient less than 0.015 when measured at a kinematic viscosity of 15 mma s and at a slide to i-oll ratio of 40 pa cent.
(048] In some embodiments, the isomerized base oil having low traction cost :icients al o alias laavs ai la> l a r ki.aaeariati: vi cos:ity ban l hith: r boilin: points. In 25 one embodiment, the base oil has a tractio a coefficient less than 0,015, and a 50 v&X*
boiling point ~~ reaa,e.r tiaaii sÃr t : (l i}^ t3 .l 3. In another embodiment, the base oil has a traction coefficient less than 0.011 and a 50 wv"t% boiling point by ASIM 1) greater than 582'C, 0080" i.
[049 In some embodiments. the isomerize.d base oil having low traction :?0 coeltici e.nts also displays unique branching p aoperties by NMR, including a branching index less flu m or equal to 23A, a branching proximity greater than or equal to 22.0, and a Free Carbon Index between 9 and 30. in one embodiment, the base oil has at least 4 w.t%o naphthenic carbon, in another embodiment, at least 5 wt% aaaphth n:ic carbon bye n.Md-- M analysis by ASTM D,3238-95 (Reapproved 2005) with normalization.

[0501 111, one eiribodime.nt, the isomerized base oil is prodncr'.i1 in a process wherein the iotetiirediate oil isomerate comprises paraffinic hydrocarbon compOne:nts, S and in whieb the extent of branching is less than'? alkyl branches per 100 carbons, an f.
wherein the base. oil comprises paraffinic hydrocarbon components in whicMi the extent of branching is less than 8 alkyl branches per 100 carbons and less than '20 wt % of ihe alkyl branches ate at the 2 position. In. one embodiment, the FFT
base. oil has a pour point. of less than -ST .; a kinematic v iscosiÃy" at .100 C of at least 3." mm o and a Viscosity index gre te:r fl, um a viscosity index calculated by the equation of 22 x Ln (kinematic viscosity at ..1 ()0 C,' -1, 132, JOS I I In one embodiment, the bane ofl comprises greater than 10 wt. " % and less than 70 wl, % total molecule:, with cyclop rraffinic functioiiality, and a ratio of Weight percent molecules o i 1i m ;no yeloparaf nic function ility' to L ei slit percent molecules with 3lttiltl " :Itipai~ itini:c f.aanct.ioua.bty t3rcater than IS.

[052] In one embodiment, the isome ize baw oil has an average molecular weight between 600 and 1100, and an average degree of branching in the molecules be twee. ii 6-5 and 10 alkyl branches per 10 0 carbon atoms. Ili another eml-+od ment, the isonierized base oil has a kinematic. viscosity between about and about. 25 ElliXl2,'t 20 and an average degree of branching in the molecules between 6,5 and 10 alkyl branches per i00 carbon atoms.
(0531 In one embodiment, the isomerired base oil is ob. ai:ned from a process in which the higlily paraffinic wax is hyydroisomerized at a hydrogen to f .ed ratio from 712.4 to 3162 liter 11,11 liter oil, fbr the base oil to htive a total weight percent of '25 molecules, with cyeloparaffmic fun tionaliiy of greater than 10, and a ratio of L eight.
percent molecules with monocy-cloparaffillic imebonality to weight percent molecules;
with -multicyclop a'a nic .t mc.tionality oà greater than 15. in another embodiment, the base oil has a viscosity index greater than an amount defined by the equation; 28 v tt vis,,cosity t 1 tf ', -t- S, in a Ãhird embodi.n em, the base. oil 'eF comprises a weight percent aromatics less than 0.30, a weight Percent of molecules with e:y~cloparaffin c functionality greater than 10; a ratio of weight percent of molecules with monocyc.loparaflinic functionality to weight percent: of.
molecules with In(11-icvcle~l7tarÃrltinie f'tri3e'ti EialÃty' greater than 20; and a viscosity index greater than 28 x Ln (Kinematic Viscosity at 1 is 0 C.) l 10, In a fi?i rlh t mbod.imea t., Ãh e base oil further has a kinematic viscosity at 100 C. greater than 6 In -a fifth embodiment. the base oil has a weigh percent arosiliaties less than. OAS and a viscosity index greater than 28 x Lit. (Kinet.natic Viscosity ait 100 C.) 95. In a sixth embodiment, the base oil has a we ght percent. aromatics le;.s than 0.30, a weight percent molecules U.-ith cy .dopataffinic functionality greater than the kinematic viscosity at 100 C, in ttirr?/s, multiplied by three, and a ratio of molecules with raonocycloparaftin c t\aractioiiaatity to mole- .ulc:s with icaca:Ricy"clopa r'at inic Ãaanctionality greater flan '1.? .
[;0541 in one eir bodiment, the iso merizÃd base oil contains between `3. and 1.0 wt% i?aphtl.~enIc calm- on as i.F"se sur d. by ii-d-IL's. "ln one e`i?:bodtatxs:.:?t, t e base oil 13a~
a l ii ematie s>scosi: :?$ 1.5 3. .i F .i\ s tit 1 [i(3 C`, aril 2 _i s t' Ã i f ithenic carbon.
In another embodimei t.., a kinematic v.iscosiÃY of 1.8 - 3.5 .ii?.iii`; s at i 00 C. Hind 2.5- 4 wt"'% naphtbenic carbon. In a third embodiment, a kinematic vi'scosity of . -6 mm-/:s t:s aat .I00 '. aind 2.:/ - `''c~ t% Foal httaenkc carbon. in a fi. urth et bodimei t, ai kinemati .=
viscosity o.f 10 31} t.Fi t . at i 00 C and between. great r thin 5.2 % and le i; t San 25 o, wt%%% naplAa.ci?zc Carbon.

ar 41 F Ii: f?,'ie i"iF ?i?i i7.Ff'F , the t? Reif l3:Zi-E 19<~`. +~;1 lzi_iS
~~.2`a s'i ri aiif'G iT.Ft?. S Cii l ~zei,3lit greater Ã.Itai? 4 75; a vi cosity inc.ex f re ster than 140, and a.
we.ig ht per"ce11.t 20 olcfl as less than 10. The base oil improves the air .relea::se a and low fo 3ming characteristics of the mixtf're when inco porn ed i to the gear oil comF' posit on.
[056] In one e ribodiment, the sc?meri"rccf base.: oil is a white oil as disclosed iÃ, 13.S. Patent No. 7,214, 307 arid f.US parent Publication US20060016'124..I n one embodiment, the isomerized base oil i i :F 1~liet oil ha ing a kinematic viscos.ity at 25 100 t:. between a ?oEit I . ? cSt and 3? si t tai ositY inde? greater Ãhan an aa,~,nount calculated by' the equation: Viscosity> riilea-'. l:i> (the Kineariati isi t i.Ãy: <at I00 C. + 95. between 5 and less than 18 weight percent moles isle= z i.tl?.
cvclol3ataff:FiF c .functionaility, less taian 1.2 %'eight rcent molecules With mufticycloparatf'inic tImctionality, a pour point less than 0 C. and a Saybolt color of 30 , `20 or tgr"eater".
[057 of the base o.il nFaitrix is a ti_roup IV ?ase oil or a mixture of di#fearent Group l V base oils. Group IV base stock consist. (Fl l oly>a.1phaoletins ('PA.Os'>), offering :up; rior volatility, thermal stability, o.xidadve st ahiliw and pour point characteristics coniparoil to those of the Group 11 and 111 oils,ESwith ÃÃ ss reliance on additives.
[0:58] P.AOs comprise a class of hydrocarbons manufactured by the catalytic oligon1e:.riz.aÃioia (.oiymenzation to low-molecular-weight products) o%
linear a-o ie,fins k typically ranging from 1-octene to I. dodecene, alt hough polymers of lower olefins' such as ethylene and propylene can also be used, including copolymers of ctlaylene with higher olefins. High viscosity '::~ may be cos veniet tly made by the.

?i?lyme anon of ,a {3-o ,.F1 in the pre F:rct of a polymerization catalyst such as the I ricdel-CCrÃai s catalysts includinnL. for example, alurnir? mi trichloride, boron trifluoride or complexes of boron tri.fluoride with water, alcohols such as ethanol, propwnol or butcane?l, carboxylic acids or esters such as ethyl acetate or ethyl N" 3Fo.ilatz .
10591 In one embodim rt, the PAO used is predominantly a=oletin, that is, linear terriainal olefin, By predominantly is meant that the P AO contains over about fit) a?ac?le perv :nt. ;3t e c?lefi ?s. 1n another et:al os l>ttt.a Ã, 1 e P
t.t as <a 1atÃ?lz viscosiÃ
PAD., comprising hydrogenated polymers or oligomers of ca-olefins. Th u.-olefins include, brat are .n t lii??.ited tea, tau to ztbout t,s ct-ole fins, c, ., I
octe;.ne, 1-deco e, I-dodecene and the like. In one example, the P.AO is a a cilelins selected .(zc?:sat the ;ro p isf poly-1-Octene, poly-I-dec e::ne:, acid poi -1-~:1c?decene, 2.t1 [0$01 The. PAO product ,04r use in the composition can have a wide range of viscosities, vat 'ing frown highly mobile 1ltaids o "lower lscosity, about. 2 ttmtra s.., at 100 i' , to higher molecular Weight, viscous materials 'hich have viscosities exceeding 1000 to iai`:!s (cSt.) at 100 'C. The PM) base stock for use in the.
composition, can have a wide range of E iscositie a, varying from highly mobile fluids of low-viscosity, 25 about 2 mm`fs,, at 100 "C to higher molecular weight, viscous materials which have viscoSFi.ties exeeedino 1OOt) mÃai`; s (cSt)at 100 "C. Iii one embodiment, Ãhe. PAO
base stock has a kinematic viscosity ranging from 2 to 100, tartar s t:eSt.}
at 100 'C.
[061] In one. embodimer t, the PAO products have a viscosity .ranging from 40 to 1250 nina''is `cSÃ) at 40 'C. In one embodiment, the PAt) has a %i.scosit y of 30 greater than or equal to about 80 mmT s at 40 C and less than or equal to about 20 taaaa sat l.00 C. In another embodiment, the I'.AO base stock has a kinematic, wiscosi't4 ~ ~ ''t.;, it3 tile: range z?1 fit) 11th sit:?`` . and a kinematic viscosity @ 100''C-of 10- 16 n;.tt/S. and a viscosity index of 140-160. In yet another embodiment., the P case stock is a blend of differenà PAOs, one having a viscosity o rat =,i~
,; fro.
30 -- 60 xviii' s at 40 " C. and the other having a viscosity of 300 600 : im`
`s at 40 C, for a PAO) blend having a viscosity of 100 axun-1 s at 40 [062] In one embod.irrient., the gear oil composition is characterized as having a sufficient amount of ison err ed base oil for the conipos aou to have the desired. seal compatibility, oxidative stability, and load carrying. capability, In one embodiment.
this sufficient amount of isonierized base fail (component: A) ranges from 20 to 75 wt.
(based on the total weight of the gear oil coniposiÃ:i.on ). In a second embodiment, the sufficient amount of.isomerized base oil ranges from 00 to 60 wt. %. In a third embodiment, the sufficient amount of isomc sized base oil ranges from 40 -.50 wt. %.
[0631 In one embodiment, the Lear oil composition ctmiprises a blend of s0 to 40 wt. % (based on the total weight of the gear oil composition)) of an isomer'ized base tail having a kinematic viscosity at 100'C,, of' 3 to 8 intri`; s., a viscosity index of l45-`65, Oxidator 131 of 15 to 5 lours; and 60 to 7,0 wt. % of a ;.sly-u .olefin having a.
5 kinematic viscosity of about 4(1 inm"_, s at 100 Ã". In another.mbodit ment, the gear oil composition comprises a blend of 40 to Ã; wt. % (based on the total weight of the gear oil composition) of an isoriieriz.ed base oil having a kinematic viscosity at 100 Ã.`..
of 10 to 20 mm/s., a viscosity index of 155-165, O:xidator 131 of 1 S to 25 horn's; and 35 to 55 wt. % of a poly-u-olefin having a kinematic viscosity of about $0 ---10Ã0 .nura` is at 100 'C.
[0(41 ~,Nddit'oc al f ~;icyz _à trrtl à its: In one embodiment.. the gems coil composition comprises 0,01 to 30 wt. `fia of one or more additives selected from dispersants, viscosity index improvers,, pour point depressants. a-mif:oarning agents.
antioxidants, rust inhibitors, metal passivators, extreme pressure agems, friction niodit.iers, etc., in order to satisfy diversified ch aranteris`:.ics, e. g., those related to friction, oxidation stability, cleanness and dcfbamin -',, etc.
(065] 'Examples of dispersants include those based on polybuutenyl succinic acid inside, polybutenyl succinic acid. amide, benzyla xune, succinic: acid ester, succinic acid ester-amide and a boron derivative thereof When used, ashless 3ÃÃ dispersants are typically employed in an amount of 0.05 to 7 wt, %. In one embodimeant, the dispersant are selected from the products of reaction of a polyethylene polyarinine. e.g, triethylene tetraamine pentaamine, with a hydrocarbon_ ssubstituted anhydride made by the reaction of a polyolefin, having a molecular weight of about 7Ã:Ã 1400 with an unsaturated polye a hoxvIic acid or anhydride, e:t . maleic anhydride, [066] Examples of metallic detergent include those containing asuffonate,, phenate, salicylate of calcium, mahpies.ium, t?arium or the li.ke., lMetalfi .
d tergents S when used, are topic: ally incorporated in an amount of 0,05 to 5 wt, 067 j :l:>> ampler of amiox.id.ants include but are not limited to arniine-based ones, e.g.. alkylated diphenylamine. ph .aayf-tr-rya ht lzt tiny and aikylated p.hony ie?e; A?fly-r?c?1 1?;~s cf ones, phenol, f, r etf yien r ; -di-t-hutyl phenol) and iso iz ty1 3-(3. r i-t- iFti'i- -xl girt? phenyl rrr ia?nate; sulfur-s rl based ones, g tiifa.r l E, t` tfxi~?dil?r~?l?it?z3 its: and zinc dith ophosphate. When. us ,d, arnio.xidams are incorporated in. an amount from 0.05 to -wt A, [068)) Defoarr i.n ads sit. i i be optionally incorporated in are amount of 10-1Ã 0 pptr. Examples sf: deti?aania?g awe is inc:lude but are snot l m ted to slimeshyl po`ysiloxane:, polyacryinte and a fluorine derivative thereof, and poeffluoropolvether.
Rust inhibitors can he used in an aims ant: froze? 0 to 30 wr t Examples include a fatty acid, a alkenylsuccinic acid half ester, t c ty acid soap, alk~ l crlli?trÃate. poly hydric alcohol `fatty acid ester, fatty acid amine, oxidized paraffin and 411; 411x 13 z?x et _.>lenc:
ether.

[.069 Friction modifiers can be incorporated in an amount from 0.05 to 5 =avt.
0 % Examples include but are :not limited to c?:a una~n?c?ls l lenarre l?a rr:r compow-.0s, fiin acids, higher alcohols., fatty acid esters, sulfided esters, phosphoric acid ester, acid phosphoric_ acid esters, acid phosphorous acid esters and amine salt of phosphor c acid ester.
1070] Small amounts of traction reducers, e.g., from 0.5 to 10 wt. %, can. be, incorporated in the gear oil composition. l xample i of traction reducers include Exxon ,Mobil's Norp arr4e fluids (comprising normal paraffins), fsoparr,"flu ds (comprising isoparafilins , Exxsol"I" fluids (comprising dearomati real hydrocarbon Euids), Varsol M fluids (c:o prising aliphatic hydrocarbon fluids), and mixtures thereof.

3 1. 71. ]] Anti-wear and/ or extreme pressure agents can be incorporated in an amount from 0:.1 to 10 v t. `'o. a xarrtples of anti-wear- and!" or extreme pressure agents include metal-free sulfur containing species including sulftr ize_d olefins, d.ialkyl polysultides, di arsl }~ lascaffide , sultiuized fats and oils, suffurl ed fatty acid esters.

trithion", sultur'izcd oligoraers of ('2-(.,8 monoolefins, thioplhosphtorc a :ik.
compounds, st 'ttii i:rc' .l terpenes., thiocarbainate coinpou ads, t iocarbonat e compounds. sui osxides, thiot scaifnates, and. the like. Other exaniples include metai-frce phos horns ..ee~at i~ .ira antiw tt ai . orextreme I?tc.ssu s:ldiÃives such esters t of phosphorus acids, amine salts of phosphorus acid:' and phosphorus acid/esters, and pit tial itt ct tc?tal thi;t analc s of: the .ii?.r ~3ir.::. none ~:mbod invent, the composition comprises an acid phosphate as an nati wea' agent, with this agent having the.
}_t9rgt'.u a RtO(R2O)(O)()1I- where Rt is hydrogen or hydi=earhyl and R i:. hydrocarbyl.

t0721 Pour point depressant can be incorporated in an 3Iroum :ranging from copolymer, condensate of chi +rinaied paraffin and naphtbalenc, of chlorinated paraffin and phenol, polyt methacr'yfate, p(lyalkyi siyrene, chlorinated wax-. apirthat ne condensate, vinyl acetate- um agate ester cop,-Ayme-T, and the like.
[073] In one embodiment, the composition further Comprises at least one, of a t? f a'sl~'i? , <tlk it sac g iyc:ol, polyoxyaik,ylene glycol ether. and an ester as a so l biiiring agent is an amount from 10 to 25 wt. %. Examples include esters of ai dibasic acid e.g.., phhalic= succinic. ilkyisuecinic, alke ylsuccinic., Lactic, a Felai , suhcr e, sebacic, fumarie or adipic acid, or iino:lic acid dimmer) and alcohol (e.g,, butyl, hexyl, -etl ylhe yl, dodecyl alcohol, ethylene glycol, diethylene ,Ytycol rrironoetlac:A' or .?0 propylene glycol); and esters of a mo marbo? ylic acid of 5 to 18 carbon atoms and polyol (e ... fteogentyl glycol. trimetl y>iolpropane, gents ervthritol, dipentaerythritol or tript.ntaetst rit+~l); polyoxyalky'iene glyco esierr and ;;hosphate ester, 10741 In one embodiment, the composition further comprises at last a metal passivator, and sometimes secifically a copper, p ssivator. Exarnples include thiazoles, t azoles, and thiadizoles. Specific examples of the thiazoles and iltiadii oles include w m rca to-l.3,4-t it adiazo.l; i7tera:t.?E13- Y-la ida+3;:~%t'l~o'llil 13,4-thtadiazoles, r;er~ tl~to....lkedr3c~ rl~Lizt it is-1, tlii;ad.iazoles, 2.5--bis.
t' edtc-c:a l?~lilaif} 1 3,1-thia1? holes, a xd 2, -Iris {la3'tfec?c arhy clitltio)-.1._ ,4-tbla ia.aoles. Other suitable inhibitors, of copper corrosion include imid azolines, 3t1 described above, and the like.

05 in one emltbod.ime .tt., t be composition further comprises at least a viscosity modifier in an amount U0,50 to 10 wt. %, Examples of viscosity modifiers include but are not limited to the group z?f Ix?ler~ et.lratc relate type polviners, c thy lone-propyierle oupo?1ymers, sà -re e..-- sopre ne copolymer's, hydrated styrene so retie f?Ã7d?{}+'m rs poi 1 isohu :v E'.":1 :, and mixtures thereof.
In one embodiment, the Viscosity i odi0er is a blend of a pc lytrietbacryalte having a weight average molecular b eÃg Iht of 25, 000 to 150,000 and . shear stability index Iess than. 5 and a polymeà haccry ate having a weight average molecular weight of 500,000 to 1,000,000 and a shear stability index of 25 to 60:
[076] In one eraabodiment, the gear oil composition opt onally~ Comprises a sufficient amount of pour point depressant to cause the pour point. of the hydraulic fluid to be at least 3"C, below the pour point of a blend that does not have the pour.
0 point depressant. Pour point depressants ar known in the art and include, but are. not limited to fistedr-, of maleic anhydride-styrene copolym ers, polymcth- cr laves, polyacrylates po?lvmcr'y'larmdes, condensation prig tic:ts of hale paraffin waxes m d aromatic compounds, vinyl earboxylate polymers, and tcrpolyyme_rs of dialkylfliraaarates, vinyl esters of tatty acids, ethylene-vinyl acetate c(ilamlymer's, alkyl à 5 phenol formaldehyde condensation resins, alkyl vinyl etlrers, olefin copolymers, and mixtures. tereof.
[Ã} 1, l1K''nj t In one c:. boda.mem, the gear oil composition is characterized as 1xing wry stable for use Willi a wide, range of temperatures With a viscosity .index (VI) of aat B a it 140 ( pith less than 0.5 wt,% oreven no Vi itrmrnaert.
20 ira another e tral>odiment, the gear oil composition has a V.1 of at least 150. In a third embodiTaae.nt, a VI of at. least 160.
[07S A typical test for oxidation stability is US Steel x-200, which its used to measure the ability of gear lubricants to resist oxidation and the fora isÃion of deposits b hei~a subje.c.ted to hitgh operating temper atures. Flat tlae. end cif the:
test period., tare :15 viscosity is checked for change (maximum of five percent increase), the test utensils are inspected for sludge or residue and the lubricant color is checked for evidence of chary e (darkening). In one embodinne_nt, the gear oil is characterized as having- a high oxidation stability when tested per à S Steel 5-200, with a viscosity increase in oas', embodiment of less than 3a:%. In a second embodime".at, a. viscosity increase of 0 less than 2%%, in a third en.AxAiment, of less than 1%. The amount of precipitation tinder this test is less than 1 % in one embodiment'. less than 0,0% in ,a second embodiment, and less than 0.03% in a third embodiment.

[079] In one embodiment, the gear oil composition is characterized as having ai 'ir? ken Ã;ti~:.Load. of gAeate:.r than 60 l:h.. fn a s cond fi lY
bodime:i~.t,. a. finrken à ,.
Load of greater ?.hAan 70 lb. In a third e<im:bodiment, greater than 90 ih.
[080] In one el bodime.nt. the gear oil composition is characterized as resulting in an average volume change (swell increase) in a rubber seal between -10 and -10, and a change in shore A .liardric ss etwee . _'; and 10 when tested with ~43~3 BR-18 at I00- .'., 1Ã 8 hours (per DIN 51521 and DINN-:5:355Ã35).. In a second eembodii lent, the average volune clump is bev-veen - 5 and r5, and a change inshore A hardness between --5 and A-:5 when tested per DIN5352l and DIN 53:505.
tit [.081) In one embodiment, the gear oil composition is character r.ed as having low foamin teendency and excellent air release properties. The foariiing tendency of the Gatti he mealsure.d using tl>e ~ õ':(':s 1)892. 2Ã 0 7 Ii arx test, in one embodime._t t the seer oil composition shows a sequence 11 foam tendency halt height of less than 75 ml- in yet another embodirne zt, the gear oil composition shows a sequence a sequence. ti foam height of foam he ig ht of less than 40 ini,. Ina third enibodimen.t, less than 30 ml.. In a tifh embodita ennt, the sequence .1.1 fiham height is less than 2.0 m1... In a sixth <:nibodiment, none can he. measured (0 mL).
10821 Air .release properties can t measured using Cite .:'GIs`:`M 1:t 3427 C4006) method for `as bubblese.paxation time of petroleum oil to measure the ability of a fluid to separate entraair ed gas. I c~at;> .tlZbodizx ent, t1Ye ca' d it ~.rFit po ition leas a fair release tÃn e at. 511 ' ,eft IV s tf an lt} mi>3UtCs. in a second embodiment, an air zeleasc tulle of less Ilia Y Ã.Yinute:. In :a third embodiment, less than 7 111inute;s.
0831 1dfic8t c el fe~.r -1<d it :. Additives used in formulating the gear oil composition c n be blended into base oil blends individually or in various sub-combinations. In one embodiment, all of the components are blended concurrently using an additive concentrate (i.e., additives :?ins a diluent, stuch as a hydrocarbon.

: an additive Gd3l10elYti'fite takes advantage of the mutual SoIL`:Ãet). The use 1s compatibility afforded by the combination of ingredients when in the Form of tat additive concentrate, in [024] In another- embodimont, the composition is prepared prepared by luh-i rg th base;

oil and the additive(s) at an appropriate temperature, e.g 60 ,, 11116l homogeneous.
2 t [08 .1 =... ?piica ,ons; the ct3~Ãx ?c;s.i i~~.a is s~ .l iii in ~: ny systÃ
tta .}~ t ins: (Ã Ãit eleÃneats or Parts p ort in.ing gear of any kind and rolling element bearings.
III one.
e xabodiment, the composition is used as a gear oil for lubricating industrial gears, i .
spur and bevel helical and spiral bevel, by oi.d, worm, and t =ie like, hr aanother t embodiment, the Composition is used in automotive / mobile equipmtmeÃtt ap?p?Iic xtio xh and parts, including aircraft propulsion ssys.ei'mss, aircraft transmissions, wind turbine geaari, automotive drive trains, trMisinissions, transl r cases, and differentials in a automobiles, trucks, and other machinery, In yet another embodiTn 3t., the, composition is used in wind turbines, plastic extruder gear boxes, and highly.
loaded io geni boxes used in electricity generating systenis, or paper, steel., oil, textile. lumber, cement industries, and the like..

[08o1 1.\<A\IPLhS 11e e.> aiatplc; are given ac: nun.-limitx6io i lust-a-ti ns of aspects of the iilvention. Pro, ernes of the isomerized base. oils used in the c camp es arc. shown in Taal-lble 3.

t:? [087 1 alaikples = Two gear oil compositions there formulated accoraiing to the amounts in Table I and tested.tbr seal compatibility. Test Methods DIN

and DIN 53505 were used for SRE N 3 R-='w8 nitwits. hutadiene rubber amid 75 f uorL~Ã:lais`i~-na :'r= =Txe components in the examples vare as follows-[0981 F'FBO-lam (W()W9 98 ) is an isomerized base oil from Chevron 20 Corporation of Sa n E amon, C A. The properties of ' '131 -L. aare s ao as Iaatble 5.
(0891 PAO-4 and PAO'40 are polyal has olefin ("P.AO") base oils having viscosities of 4 eSt ( I t?EI` C.:rid 40 s. ;ia? 100'C., respectively, Ã 901 Additive I a i?la: a 3 <<t :? is a hindered estCt additive.
[091] Additive 2 (i ubii: ul 51058) is a gear oil additive package from ?= Lubrizol.
[092' Additive 3 (TX 4238) is a s i ri>iti rcially available additive package for gear oil.
[0931 As shown in Table 1, the gear oil example cumaiprising at least. an iso.i er.i red based oil shows a smaller decrease in the mechanical resistance of nitrile ?0 and fluoropoly>rner rubbers chau e in max elongation. and tensile strength at break), less swelling (volume increase) and less weakening (fecreasÃ: in l ardn..ss ) c,'fthe luoropoly inner Ribber.

Table I
====........ ""' Components Example I Exam?le 2 PAO 4 CST 34.00 PRO 40 CST 58.46 58.413 ........--'- '----' - ------------------------------.00 Additive I APR OLU;3l ~t~7 00 5. 0t3 ae*titibe 1l ~7lrci~1: - -- 2.50 2,5i rkL`lkivE.: 3 `1 t 42?::
O W2 0.02 ---- - - ------i r _::.al "00.00 ? 0.x.00 Test Results ._'=_==-==--K. Viso. 401 Cl +r imr hi nc.~4 KiilViso,.. 00"f.~,r im2 i42~3 13 81 Seal compatibility SR -NBR 28 DIN 53521 1 - - ------------ -elatty' vi?lu.rn ct~an e, `c DIIN 53505 3.3 ..
ii Change in ai';v---- A hardness, %
Loss of tensile strength, % 15 =14,4 _----- ---^" ............. .
DfFci'ease in elon0atinn at breakage, 28'7 - ----- ----------------------------- ----------------Seal compatibility 76 FKM 586 "=-====..__ -----------F~31lftest (130'c' . ?
Change m Hardness Shure A, % --------------Relative vohirle ciidrtge, % 0,7 0.7 Change tt terisile strengtt~, % 61 5 Change in elongation at breakage, 1 3- .. .'Y .
7c:
.............. ---------------------------- ----------------------- -="_'---=-------- ..._=- _._..,.,... M -=-_=_-=--------Storage at mom temperature , ...,, ,....
}-----=---=--=--=--==---------------------=--------..-._..........---=----------- .._........................
week 1 = Bright and clear - -----------Bright and Clear M .._.w.__.. week 3 Bright and Clear weak 4 Bright ant Clean ------------ ------ - -----[094.1 Examples ~ ..6: In these e.. amples, gear Evil lubr ea;nits meeting ISO
ISO viscosity grade were -fo mulated according to aniounts in Table. 2 to compare S embodiments of the invention with gear oil composition containing POA basw oils-only, e .g., Iiinken OK loaf, oxidative stability.. air relt_ sÃ:: prop,:n s.:ft:nIVA- sibillty, cotlipa ibilit ' with various seas, rust and corrosion prolcc,Aiion. The components used in the examples are as follows:
1095 PAO-6 and PAO-l00 are polya plha. olefin ("I'<AÃ.3") base oils having à viscosities rat Ã? cSt ;~i': I t}t)`.C. and 1 0 eSt ti 1 t t~'#~:., re spe:
;~tivel '.
'"096-1 'II I=I3O ( Q2249 i3 an isorrmize:d base oid 1min Cpl c vion à orporat on of Baia Rwr on, C.A.
à )71 Additive 4 (Eat, rex A51.) ism adipate: ester solubilit - additive.

.09S] Additi~ e { ~ io be :x970) is himl; d est r <~d ià ve.
[0991 Additive 6 (1, thriz l 5058) is a gear oil additive package rom Lubr=.lzol, [Ã1001 .Additive 7(kfineu .r G-461) is another gear oil additiive package, from

4 l: ofÃneu.m international Lid, [01Ã011 Additive 8 is a co inerci ally available foam inhibitor additive.
Table 1 --------------------- A ....
Components Exampre Camp. Comp. Example 3 Example Example 6 PAO h 59.44 422 t?) 10Ã7 17,51 42-f)6 41.31 31.59 t5 00 -Adthtwe 4 (Esl 2rex A > 1) Acd trtie 5 ÃP'nulrul,a`` A r0~ 5.05 5.10 23.00 fiat#tive 4 Ãb y in l 2 .,50 2.50 2.50 -4 ... ---- ---------- _.._õi Add-tine 7 tanfireum G 3Ã1 1. ik= ..
...
Tot" v" % 100 10.1-1 100 100 ............------------------- -------.........................-- - _-......-------- . ----------- _ Add ive 8 00.005 0.005 0.005 0.005 Tests ?età od "tea .' 48 Vi e, Kin, at 40C, -St 0 44 -O6 14" 1412 -- - ------ - ----31à à in, at '1000 t 0 445-=U5 19.99 19. 1 }.t 2 ? ~
t 3 1vO 166 i ^o;s index r^:kk i D 22 0-(>W 164 Ail Ykavitp 32.1 C u Strap, 3 Hr eq 100 (max) M 30 (E:200 i) 1 ? .... c .............
' 1 a Pout à eint (max) t? 5956-~:2 13 -,-5 2 --51 -26 Appearance ;max) 2 2 ----Timken OK Load, It, 0 2782 - 100, 85 95 95 65 2t?.~
FZG. Pass stage 12 12 eat. 12 est. 12 12.
Rust D 665.1 ----------- --------------A-Distilled water 8-S r Chet c see hater Pass Pass Pass ----------- --------------------------- --------- - ---------Oxidation, 121C 312 hr. U., Jteei 1Oll/hr air - - - - - - - - ------------------------- - --------------------------Vis increase(%), max 5-14109 21 2.4 1.84 0.53 --=---'----------------------Precipitafo: r no. after test 0.10% t ;1 <0.02 <0.01 9 025 - ------- ------- - - -- ----- ----- ---- ------------0enwis;bi Ãty, for 90 ml water ------------------------- -------------------------------- - --- ---------------- ----- -- -------- -------- ---Water in Oil (%) max 0 L105 0 Tota: free water(ml), min 8 . 86 39 . ..
Ernuis.n,m ), max 1 0.L~u. ..
Thermal Stability 0 2.1179 (Cincinnati Lamb (R 209Ã6) Vse. Change, 49/1900. 1,6 - ------------------S udge, mlr'103ml none

5 - ---- ------------------------------- ---------- -------Ou Rod LoZ17 tCiriwa; h..i &
--------__---- == .................
Steel Rod Color à I

tech. i --- ----_.....-....__-__-_=-~-=~-=--------------Copperia'Wei ht Loss' mg 1,70 Ste :Ã r ht Loss erg `.8 Copper V,-' ght Deposit, f<.
Steel Weight Deposit, rng .' rsa t d rto y- # laÃBa4 + 0892 (E2007) Sequence I, MI 3=0 8'0 ............. ..........................
Sequence U, ml s /t 0/0 13010 }+`l ry ------ --------Four Bait Wear, 54C, Scar diameter, rmm, teak (.:t U1 0.25 Four Bait Wear, 75C 17-2(E2006) Scar diameter, 23'E?'{l, rr7caX - 0.43 0A0 ------------Lir Release, min O3 F 6.58/? .1 i 8.62 8.5 r Four Bali P U2; 83-00>
---------- ------- - ---3 ? 25 _ x' &d Load, fig 315 15 Last Non- i are`U J E ; kg 63, 10G 1ra0 100 126 - --------- ------------1 w .t.
i U,saa 'v"+ ear Index, fig 3113, Ã

--------------------------------------------------------------- ---- -----------_-----_- mow-? Compatibility with Seals --yslt c~tt - ------- - --------- -- - ------- --------------- - --------- - - - - --- - --- - --------change f Atl~'ri"ga`. elongation ? no re-SO .=
Vitt-Emne change, %
1.=r5 no t o resu.t Shore A Hardness change, .=3. - no result `"3ta E,at't --------------- -- ---- - - ------ - ------ - ------- - - - -- - - -------- - ------- - --- - - -------Average t~` oingatk n change -0.22 Volume change, ,=i: sa` .:xõ18 n aw Shore A Hardness change, Eats i = = a Acryiae Average elongation Change =.. --==-=I
Volume c nan e. `lp t ,2 1._~ Y=-_, =_ Shore A Hariine&
s char e, E 4 1 ~'1 iPts -.=
Ski: t=il't _1.12 Average elongation change -.1 , i o ------%
Gl7cai A Hardness change, -7/+10 3.32 1.4 .t~
Acid Number _ 0.50 ; 0.7 1 0.51 i ------- ------ - --- -----[0102] . _3 shown i- the. above Uahic:, gear oil compositions containing a mixture of isomerized.. base oils and PM) result in better lubrication, better Ioad Carrying c apacityr as shown by Timken, 01 Load, better oxidative property (as suiggested by less increase in 8 'scosity as show: "by S-200 US Steel test), better load t,.wav:ing capability as shoo n by Four Ball EP test, higher weld load, higher LW Index and no seizure load, better air >eicase properties, excellent de.tt ulsihilitv, excellent co m patibilitti with most. coninion seals, u id good rust and corrosion protectiorn.
Table 3 Properties 1="i Lr ~ià TIC) C hes+r~ i t t IV WOW B98 00022D4 Kinematic Viscosity @40T, nitn'/s i, 4 Kinematic Viscosity :100CC, mrr:`'1s 4,039 -3.9:9 ---------------Vis: osity index 160 15 Cold Crank Vs.. @-400r,, r Pa.L 4.50 à r nk Vis. -35'C, mPa. 1,335 ------------ -Cc~Ãe3 Crank ViM. t -30'C, mPa.s C:~ala1 Ciarlk Vis. =26"C.:, mPa.s u Pour Pont, 'C 25 -6 28tf,{+
Aniline Point, 'F
r,_d-m ((AS i'i'i D3238-95 Reapproved 2005) normalization to 100% toll l t,%
c r~on i M1;;,:we= iE r gm/ of (VPO) 416 73;
1`r lsit4+: # ni ml C}.81 'o c?. &ri?J
--lii'=tr;.iG~i~~E,' lrt"1~>= i .43:5 Paraffinic Carbon, %
Naphthenic Carbon, %
--- ------------------------Aromabo Carbon, %
Traction : oe finient tn$ 95.^,St 0.0241 Noack Valatiiity+ W',. 13.01 CCC Rash Point. C
`a"1111tri57"i Ã" (WT%), F LASTN9 P-635.2-'N1 TBP `_0.5 418 947 TOP@5 723 963 -rep @10 741 .= 2 P (e ?2. 763 990 - --- ----=--TBP @@,30 7,60 1086 'rep 0 796 1025 ------------ --------- --------------rB@550 812 1145 TBP @60 829 106 --=-------------- ----------_,---TKP @70 847 1090 TOP @8" 667 1122 rep w30 807 1168 `i-BP ;.;95 399 1203 TBP @99.5 921 1 1273 r~c~nii Ãe it tr ducti,~it FIMS by Probe Alkanes 78.9 5S=
1- irisai~ raticii 20.3 fa-_... 3 3 `
2-Unsaiuration r 0,8 .-t n turcation 0 4-unsaturation a; 0 5-tir}~e3>Eereitl(~r1 - ---- --- - ---------------NMR iÃtrai sis:
Br ti hinq ndex. 26.18 210 ------- -------yr~tyct:ir~iarcix~rrity 1s,it;~ ~<~.õ
Aik ' Branches per Mdecule 2.55 4.39 i'i :thyl Braneltea per Mo ecuie 2,36 3.43 Njett yl Ratios...... _ ~ _._.._. 4,S9 5,02 _ ikyl Branhes per 100 Carbons t9,w't --8-16 Metiiyi Branches ter 100 Cartons 6.55 %8rancnes at ? Position .10 .1010 5.63 %l~trarlOes at 3 C3S tlarl 9.t 1 104 % Branches at 2--3 ifositions .9 12.6 --- - ------------- -Percent Brame te. at 5+ positions a _w x 48 :
0.00 3,1 %Ofe`Ths by r/son NAOR

[[0103] For tltl; Surp,'se tir this specification and appended claitms, unless otherwise indicated, all numbers e: pressing quantities, percentages or proportions, and other nurnerical values used in the specification and claims, are to be underst:ood as Being modif ed in all instances by the term "about," ccondirt4ly, unless indi:c' ted to the i;on tra ry, the nurnil rical parameters set forth in the following'.
specification and attached claims are a approxir tat or.s that may Vary del en i-ng, upon the desired prop-,r ties sough to be. obtained an f. / 7 or the precision of all instrument for mt'l as 9iÃI .
the value, thus including the standard deviation of error for the device or method i4eing i 0 employed to determine the value. Pie use of the terra "or" in. tf- claims is used to ,east "and/or" un).ess explicitly indicated to refer to alternatives only or 1ne aiterrative are mutually exclusive, although the if closure supports aidefinition that rekri to only alternatives and The use of the word "a7 or "an" when used in conjunction with the term "comprising" In the claim.-s iwAIor the specification rota;' mean "one'" but 1 S It is also consistent with the meaning of "one or more," "at least one,"
and "one or more than. one." Furthermore, all ranges disclosed herein are inclusive of the endpoints and a are independently co'inhinaahle, In general, unless. otherwise indicated, singular elements may be iri the plural and vice versa with no loss of generality. As used herein, the term >.Ã elude" and its grammatical variants are intended to b7d non'iim3tin 20 such that recitation of items in a list i> riot to the exclusion of'other like items that can be substituted or added to the listed items.
01041 It is contemplated that any aspect oftl7e inertaftion discussed M. the context of one Ã:rrihodim ent of the invention may be implemented or applied with respect to any other embodiment of the invention. Likewise, =y composition of the Invention may be the result or may he used in any n-iethod or process of the inve17.tion.
This. written. description uses exampics to disclose the invention., including the best mode, and also to enable any person skilled in the a to make and use the in vontion.
The pate ntaMe scope is defined by the claims. w id may include other examples that occur to those skilled in th art. Such other examples are intended to be wits ;iin the scope of the claims if they have smicturai elements than do not differ from the literal language of the is urns, or if they include equivalent structural elements ivith insubstantial differences, from the literal languages of the cÃai txs. All citations referred herein are expressly incorporated herein. by ref:.re.[ice..
tit '1Q

Claims (15)

1. A gear oil composition, comprising:
a) a base oil comprising a mixture of at least a polyalphaolefin (PAO) base stock and at least an isomerized base oil having consecutive numbers of carbon atoms, less than 0.05 wt. % aromatics, a wt% total molecules with cycloparaffinic functionality greater than 25 and a ratio of molecules with monocycloparaffinic functionality to molecules with multicyloparaffinic functionality greater than 10;
b) 0.001 to 30 wt % at least an additive selected from traction reducers, dispersants, viscosity modifiers, pour point depressants, antifoaming agents, antioxidants, rust inhibitors, metal passivators, extreme pressure agents, friction modifiers, and mixtures thereof;
wherein the isomerized base oil base stock is present in a sufficient amount for the gear oil composition to have an average volume change in a rubber seal between -and +10, and a change in shore A hardness between -7 and +10 when tested with SRE NBR28 at 100°C, 168 hours per DIN53521 and DIN53505.

2. The gear oil composition of claim 1 , wherein the isomerized base oil base stock is present in a sufficient amount for the gear oil composition to have an average volume change in a rubber seal between -5 and +5, and a change in shore A
hardness between -5 and +5 when tested with SRE NBR28 at 10O°C, 168 hours per DIN53521 and DIN53505.

3. The gear oil composition of claim 2, wherein the isomerized base oil base stock is present in an amount of 30 to 40 wt. % based on the total weight of the gear oil composition.

4. The gear oil composition of claim 3, wherein the isomerized base oil has a kinematic viscosity at 100°C of 3 to 8 mm2/s., a viscosity index of 145-165, Oxidator BN of 15 to 55 hours; and wherein the polyalphaolefin base stock has a kinematic viscosity of about 40 mm2/s at 100 °C

5. The gear oil composition of claim 1, wherein the composition has a viscosity increase of less than 3% per US Steel S-200 oxidation stability test, preferably of less than 2% per US Steel S-200 oxidation stability test, and more preferably of less than 1 % when tested per US Steel S-200 oxidation stability test.

6. The gear oil composition of claim 1, wherein the composition has a precipitation of less than 1% per US Steel S-200 oxidation stability test, preferably of less than 0.05% per US Steel S-200 oxidation stability test, and more preferably of less than 0.03% per US Steel S-200 oxidation stability test.

7. The gear oil composition of claim 1 , wherein the composition has a Timken OK Load of greater than 60 Ib, preferably of greater than 70 Ib.

8. The gear oil composition of claim 1 , wherein the composition has a viscosity increase of less than 3% per US Steel S-200 oxidation stability test, a precipitation of less than 1% per US Steel S-200 oxidation stability test, a Timken OK
Load of greater than 60 Ib, and wherein the isomerized base oil is present in an amount of 40 to 80 wt. % based on the total weight of the gear oil composition.

9. The gear oil composition of claim 8, wherein the isomerized base oil Has a kinematic viscosity at 100°C. of 10 to 20 mm2/s., a viscosity index of 155-165, Oxidator BN of 15 to 25 hours; and wherein polyalphaolefln base stock has a kinematic viscosity of about 40- 100 mm2/s at 100 °C.

10. The composition of claim 1, wherein the isomerized base oil has a total weight percent of molecules with cycloparaffinic functionality of greater than 10, and a ratio of weight percent molecules with monocycloparaffinic functionality to weight percent molecules with multicyeloparaffinic functionality of greater than 15.

11. The composition of claim 1 , wherein the isomerized base oil is made from a process in which the highly paraffinic wax is hydroisomerized using a shape selective intermediate pore size molecular sieve comprising a noble metal hydrogenation component, and under conditions of about 600 °F. to 750°F and wherein the isomerized base oil has a Noack volatility of less than 50 weight %.

12. The composition of claim 1 , wherein the isomerized base oil has a Noack volatility less than an amount calculated by: 1.286 + 20 (kv100) -15 +
551.8 e-kv100, where kv100 is the kinematic viscosity at 100 °C.

13. The composition of claim 1, wherein the isomerized base oil comprises greater than 3 weight % molecules with cycloparaffinic functionality and less than 0.30 weight percent aromatics.

14. The composition of claim 1 , wherein the isomerized base oil comprises greater than 10 wt. % and less than 70 wt % total molecules with cycloparaffinic functionality

15. A method for improving the oxidative stability and seal compatibility properties of a gear oil composition, the method comprises adding a sufficient amount of at least an isomerized base oil to a base oil matrix comprising at least a polyalphaolefin, for the gear oil composition to have an average volume change in a rubber seal between -10 and +10, a change in shore A hardness between -7 and +10 when tested with SRE NBR28 at 100°C, 168 hours per DIN53521 and DIN53505, and a viscosity increase of less than 3% per US Steel S-200 oxidation stability test, wherein the isomerized base oil is present in an amount from 20 to 75 wt. %
based on the total weight of the gear oil composition.