CA2163351A1 - Multiple solvent cleaning system - Google Patents

Abstract

A non-aqueous cleaning process uses a organic solvent for removing soil or surface contamination from contaminated articles such as printed circuit boards which are cleaned by immersion into a sump compartment of a cleaning tank containing the organic cleaning solvent. The organic solvent is preferably a hydrocarbon solvent. The cleaned articles, now coated with the organic cleaning solvent, are then disposed in a rinsing sump containing a fluorocarbon based rinsing solvent having an affinity for the organic cleaning solvent. The organic solvent is thus removed from the articles which are then dried without waste water as in a conventional solvent vapor degreasing solvent process.

Description

2183~1 MULTIPLF SOLVFNT ~I F~NlN~i SYSTEM
, 5 The present rr, ' liu,, is a continuation-in-part l~ r Jn of Serial 801,199 fiied December 2, 1991.
Technical Field The present invention relates to a method and apparatus of cleaning c~ tu;i articles and apparatus thereof and, more particularly, to the defluxing or du~ of parts in a non-aqueous cleaning system utilizing an organic solvent for cleaning the parts and a l,ollrl.,ll.,,, ' ' fluo,uc~l,L.ùn solvent.
Backgrm ~nd Art Soivent vapor phase ~ E ~ il,g and defluxing is a process of .ai~l9 a soiled substrate (e.g., a printed circuit board or a r.lb~; ' metal, glass, ceramie, plastie, or ~ LU"~O~ part or co,ll~,ù~il6) into a boilin~, nul.~' lll ' ' liquid sueh as a c,l,'~ o~,Lon 20 or chloroflu~ Lùll fluid or admixture, followed by rinsing the part in a second tank or cleaning zone by il""~ ,iun or distillate spray with a elr~an solvent whieh is the same ~,l ' uca~Lùn or ehloroflu~luc-.,Lùn as used in the first eleaning zone. The parts are then dried by the eooled part in the eon~ia~l:,in,q vapûrs until temperature - 25 has reaehed equilibrium.
Solvent eleani~ of various types of p~rts generally oeeurs in bateh, hu;Jt . ~ bateh, eonveyor bateh, or in-line typ~ conveyor - ~ and defluxer qlui~ I~. Such in-line eonveyor degreaser and defluxer eql . ,_.ll are diselosed in U.S. 5,007,179 Patent 2~Ç~!3351 PCT/US94/06004 (entitled "Cold Air Lock Vapor Seal"), ~o,.,,,,onl~l assigned to the assignee of the present invention. Parts may also be cleaned in open top defluxing or d~a~,~a:,i"g eq~ ij "~:"~, such as that disclosed in U.S. ..
Patent ~rF" lion Serial No. 07/587,893, filed Seult,lllL~, 25, 1990, also co"""onl~ assigned. In both types of equipment, the entrance and/or exit ends of the eq~ i~ "_.,l are generally in open communication with both the ambient env;,u"",t",L and the solvent within the equipment. In order to minimize the loss of solvent from the eq~i",_.,l by either convection or diffusion, a common practice in the art is to use water-cooled or ~r~ ,a"L-cooled coils which create a co~ ,.,s~d vapor blanket over a hot or ambient zone region in the deqreaser/defluxer tank, such as disclosed in U.S. Patent 4,261,111 to Rand.
Therefore, in the foregoin~ solvent vapor phase d~ aai"g process, it is generally known to use a single organic ~ lvlu~ Lol~ or chloroflu~luuallJùn (CFC) fluid to perform the cleaning, rinsing, and dryinq steps. The use of CFC-1 13 and Freon type solvents have been, in the past, particularly popular. However, the vapor diffusion thereof into the ~ .u"",~ has been . ' ' in recent scientihc studies to be one of many possible contributing causes to the u.,d~ ,;,, ' ' global depletion of a~dtu~ ozone, and the production and use of such chlorofluo~ Lùns is currently regulated and will be phased out in the U.S. by the end of this decade.
In response to c.,~;.v.llll_.lL.-l concern, I,,d~u..l ' urluu.u~,.,.uù,~
25 (HCFC~ based solvents have been d~ p~d in the last few years to provide more e..~:.u.".,_. ~y acc ,: ' ' alternatives to CFC based vapor phase d_e~ 9 and defluxing ~1uCaa3e5. While these materials have been shown to be excellent CFC substitutes for a variety of cleaning ., ' - )s, they are cOlla;d~(~d to be aA interim WO 94128196 ~ 1. 6 3 3 ~ :~ PCTNS94106004 ,~plac~;."e"l to CFCs since they still possess a small, but finite, ozone depletion potential, although it is much lower than that of the CFCs , which they are replacing. Hence, these HCFC solvents are also proposed for global phaseout in the near future. It is generally believed that organic solvents which do not contain chlorine, bromine, or iodine atoms will not contribute to ~ Iu~ (ic ozone depletion.
However, organie cl)~n;~ which do not contain the above halogen atoms, such as hyJ~u~.all,ù,~s, alcohols, esters, ethers, ketones, etc., usually contain u-,d~i- ' ' llan... ' " y or reactivity ,u-uu~
10 Perfluorinated lltJ.ù~,alLùl~:~ and lltJ~ Olu~.aluOl~s possess many desirable solvent p,up~,.t;~.~. zero ozone depletion potential; stable, non-reactive, high eu..,~ ' ~y with plasties; good water d;.~,ulà~...,ll~..ll potential; generally non-toxie and inert, and ideally suited to vapor phase solvent eleaning ~q~i"-~,.l. However, 15 perfluu.u-,a.LGns have been found to be very poor solvents for many ~ommon organic and inorganic soils, e.g., fluxes. Hydroflu~luc~-uons offer improved but still limited cleaning ability over perfl--u- U~,al uù-)S as the amount of fluorine content on the molecule " - .;sl-~s, but low fluorine-content hydrofluu.u~,a,Lons may start to exhibit u.. ' , ' ' 20 rla.~.... ' "~y p~u~ 5 COIll,ua~ ' ' to their l.tJ~ùca~bon analogs.
European Patent Publication 431,458 published June 12, 1991 teaehes aliphatie hydrOflu~,uca~Lol~s of the formula CnFmH2n+2m wherein 4sns6 and 6sms12 whieh are useful as eleaning cu...~ ls. Thr~ referenee teaehes that the aliphatie 25 l~tJ~Jr~ul,a~lJùn is the aetive cu~ uùn_.~l in th~ removal of the fluxes, fats and oiis, and dust from soiled parts. The referenee teaehes that in order to inerease the solveney for Jk...olv;. ,9 fluxes, an organie solvent seleeted from Il~Jlu~.alLOl~s~ aleohols, esters, and ketones may be added in an amount from 0.5 to 30 weight pereent to ~,~6~3~
the aliphatic hvdrofluo,uca,uon.
Other types of cleaning p(oc~sses such as aqueous cleaning exist. Aqueous cleaning generally involves the cleaning of a substrate or a part in an aqueous solution of dt,l-i,y~ or surfactants, followed 5 by multiple rinsing steps with purified water. The part is then dried by lengthy ~dpGI aliùn in air or by energy intensive thermal drying machines. This process is not always desirable due to the high energy cost for drying and the additional capitai ill~ lll and operating cost burden to provide aqueous waste water cleanup required by state 10 and local authorities before sewering to ground water.
Another cleaning process, semi-aqueous cleaning, consists of cleaning a substratd in a ~ J,u~,a,L.on solvent based on, for example, terpenes, esters, or petroleum distillates having a high affinity for oils, waxes, and greases being cleaned from the parts, with or without the 15 aid of a surfactant. The cleaned substrate is rinsed of the high boiling ~,yJ~u.,a,Lu,~ solvent with multiple rinsing steps using purified water.
The l.,~J~u~.a.Lon solvent is phase separated back to the wash surnp while the aqueous effluent must be ,u,uc6..a~,d before sewering to ground water. Consequentiy, hiQh costs -_..,. ;AI. ~i with drying 20 energy and with ~ ,9 waste effluent are evident, similar to the before-",.,.,: )~d aqueous cleaning process. A further drawback is that the l.~J~ uual L~n solvent usually p~ `'i3; a flash point and this must be cardfully handled or blanketed with a nu~la~,.". ' ' c~".,J.dsaod çiaS such as nitroçien to avoid explosion. Nitro~qen gas is 25 much more fu,qitive than the dense vapors of a fluu,u.,a,Lon contained in a cu, ,~., .;"~ zone. Ful li ~ u~ in a number of ~ s, while the substrate to be cleaned may be cu.." ' ' with the l.~J,u~.a,von solvent, some plastics or metals may be i..cu..,~ ' with the aque_~ rinse solvent, resulting in water aL:IOllJ~iv~ or rusting of the wo 94/28196 PcrNss4/o6oo4 substrate.
C~ic~lnc~e of the Invention . It is acco, ~" ,yly one object of the present invention to provide a non-aqueous cleaning system for d,~u, "aa;"g or defluxing parts in an ~ /;,ù"",~ "y safe manner.
Another objsct of the invention is to provide a non-aqueous cleaning system which does not use water for rinsing, and there does not exist a necesâity for aqueous waste water cleanup, and whereby said nonaqueous cleaning system can be used in cases where materials are ill~,Ull~r_ ' ' with watet.
Still a further object is to provide a non-aqueous cleaning system avoidin~q the need for drying by lengthy e~ Jul"Liûn of rinsing fluid in air or by energy intensive thermal drying methods.
Yet a further object is to provide a non-aqueous cleaning system ublizing an organic liquid cleaning agent for cleaning the parts and a rinsing agent having at least a slight solubility for the organic cleaner for rinsing the organic cleaner from the part and which rinsing agent is capable of drying from the part using small amounts of anergy.
A non-aqueous cleaning proces$ for removing residual soils or surface cul~h-- ". lion from a part, in ~ "ce with the present invenbon, cu~l~uli--s the steps of introducing the part into contact with an or~anic cleaning fluid of sufficient solvency to suL~L~., "y remove said CCr~h~ r liol~ and then removin~ the part from the or~qanic fluid for rinsing in a rinsin~q agent havin,q at least some degree of solubility for the organic cleaner to remove same from the ~,uL ,1. The substrate is immersed in the rinsing a~qent, sprayed with the rinsin~q a~qent or exposed to vapors of the rinsin~q a,qent, or any c~.. alio~l of the aboYe. When removed from the vapor, the WO 94/28196 ~63~ PCT/US94/06004 part is ess6"~iil!y clean and dry. r~l~r~laiJly, the non-aqueous cleaning system of this invention utilizes a two tank cleaning process wherein a first tank contains the organic solvent and a second tank contains the ~.
rinsing agent. The parts or substrates to be cleaned may be conveyored from the cleaning tank to the rinsing tank utilizing known conveyor or hoist means. The tanks may be part of c~"~ lion~l or known in-iine c~ o~ d d~u,t,asi"g/defluxing ~ "t."l. separate open top defluxing tanks, or open top defluxing tanks modified to contain the cleaning and rinsing tanks or sumps.
In accu,.la,)ce with another feature of the invention, a non-aqueous cleaning process for removing residual soils or surface cunlalll' ~aliOIl from parts C~llp~ia~S the steps of introducing the substrate or part into an organic fluid of sufficient solvency to remove residual CGrla-l- lal;on from the parts. The parts are then rinsed by contact with a second or,qanic solvent of lesser solvency for the soils or surface co"la".;.-aliùn than exhibited by the first organic fluid solvent but having exc~llent solvency l,llalal,k,li:.li..a towards the first solvent. The second solvent (rinsin~ a~qent) may be chosen rJ,t,r~lai,ly from the fluo,u.,a,iJùn class of solvents which contain at least one 20 fluorine atom attached to an organic backbone cc,.."~r;s~d of two or more carbon atoms, with optionally other atoms also attached to the backbone such as oxy~en, sulfur, nitro~en, ~ G~ ulues~ hydrogen, or other haloien atoms; or less r~ aiJly the rinsing a~ent may be chosen from other classes of solv~nts such as alcohols, ethers, esters, 25 ketones, I,~ ùca.L~n;., snd other non-aqueous media. The parts are then dried by holding under an inert vapor bianket which lessens or mitigates the r ", ~ ty of the first orianic cleaning solvent, or, if r' 111. ' ' . the second rinse solvrnt, where such na.,.,., ' ' ~y masking vapor blanket may be formed by at l~ast one of nitro~en, carbon WO 94/28196 ~ ~ ~ 3 3 5 ~ PCT/US94/06004 dioxide, perflu~, u~,al u~ll, hydrofiu~, UCal uv~. or hyd, ocl Il~Ocal ~on.
- In one errlho~ "~"L, the cleaning can be done in a system where a solution of the hyd,vca,L,OIl solvent and the fluoloca,Lon solvent is mixed together optionally with a surfactânt as a sol~l' " ,9 agent in a degreaser. The fluO~ucalL~on~ being more volatile, provides a rla""" ' "~y SU,u~u~t~aa;OIl blanket. The same flu~lu.,alLùll would be us~d in the adjacent rinse sump for an initial illl~t l aiv~ or spray liquid rinse followed by a final rinse in the vapor.
In the simplest ~ L~ L, the cleaning can be done in a one sump system where a solution of the l~Jtu-,a~Lùn solvent and the lower boiling fluO~uca~uù~ solven~ is mixed together optionally with a surfactant as a ' ' " ,9 agent. The fluo(u~ Lon, being more volatile, provides a rla~ y su~,u~ 1 blanket, and if the soiled part which has been immersed in the cleaning mixture is held in the cond~ai~g fluO,u~.a~uo,l vapors for a sufficiently long period of time, the part can be removed from the vapor phase clean and is dry.
The term htd~uca,l,on solvent" as used herein means any solvent which has at least one hydrogen atom and at least one carbon 3~0m.
The organic cleanin~ solvent can be selected from linear or branched alkyl or alkanol ,~ùnoca~LG,~ i or ." u~ esters having at least one carbon atom in the ester moiety and such solvent most ,f~.,dLly having a flash point greater then 200F(93C~, or less ~,fl,,.l~ly having a flash point greater than 150F(66C~. Useful ssters include methyl ester and a mixture of the dimethyl esters of adipic acid, succinic acid, and glutaric acid. The organic fluid may also be selected from linear or cyclic I~,~d~ u.~al~u~s c~ 9 at least one ol~finic bond endo or exo to the ring.
The l.~rd~u~,alLu~ cleaning agent may comprise pinene and/or ~ b3~i ca".~.he,~e, or may comprise terpinene, limonene, terpinolene, terpineol, linaleol, and other related members of the terpene family.
10 ~ ~ ~
ALPHA - PI~131iE E~A - P~ CA~P}D3NE
ALPHI~ RPIN13N~ L~ ~ R~
, ~3 $1 \~U
ALP~A-TERPIN13OL WL~I~OL 2!ENTHOL

wo 94/28196 ~ 1 ti 3 3 ~ I PCT/US94/06004 The organic cleaning solvent may also consist of linear, branched or cyclic hydrocarbons c~r,L~ ;"g C,0 to C30 species.
The organic cleaning fluid may also consist of hyvloca,~on cu"i , ,9 olefinic moieties which have been substituted with R1-RI2 -~ s groups, wherein 1-2 hydrogen atoms or alkyl groups containing 1-6 carbon atoms or both may comprise the substituted group, i.e., Rl R2 R1~3 4 'I`\ /~ R5 Rlo ~\ R6 Rg R7 A useful exâmple includes 1,5- " ,~,tl.~lc~ e.
This orgânic Cleâning fluid may âlso be cv~ is~d of acyclic or cvclic monols or diols defined by the lineâr structure (1 ) R(CH2~nOH ( 1 ) R = H, hydroxyl where n is selected from 1 to 20 g ~ 33~

or the branched structure (2) R, 5 R2-C-(CH2)nOH (2) Rl where n is selected from 1 to 20 or the cyclic structure (3) o~
~ ~ 9 (3) wh~re R1-RD is defined as alkyl or hydro~en groups or mixtures thereof, and n is defined as 0 to 6. Useful diois includ~ c~ GA~ I and pol~.th~l~i.,6 ~31ycol (MW 200) (a polyether diol).
The or~anic fluid may also bs cu."~ ad of linearr branched, or 2S cyclic mono or polyl ~ , such as ~1633~ .
o Rg ~J~R12 ~ n R77~ ~4 R8 / \ R3 where n is defined as O to 6 and R1-Rto is defined as alkyl or hydrogen 10 groups or mixtur~s thereof. A useful cyclic ketone include cy~ a~ lld.
Other orsanic cleaning fluids l", ' ' ' to this invention may be c~""~ris~d of:
(a~ alkyl or aryl nitriles of the formula R- CN
where R may be an alkyl ~roup (methyl, ethyl. etCl, a phenyl group, or an alkyl substituted phenyl ~roup (b) an 'kyl~a.. ,~ of the formula Rl [~

Wo 94/28196 .,~ ~ ~ 3 3 ~1 PCT/US94/06004 (c) alkvl esters such as diethyl,uhLllalaL~ of the formula:
C02Rl (d) polyether alkanols of the formula:
Rz Rl-~CHCHzO)nH
where R, is chosen from the class of compounds defined by H, alkyl, or hydroxyl groups and Rz is selected from the class of compounds 20 defined Dy H or alky~ or fluoroalkyl groups.

WO 94128196 ~ ~ ~ 3 ~ ~ ~ PCTIUS94106004 (e) substituted aromatics of the formula:
.. . .
R
1~ R~A~

where R,-R~, is chosen from hydrogen, alkyl, fluoroalkyl, or halogen 15 groups and c~,..' .aliùns thereof, such as trifluu.uL~.~.J.~e.
Such organic cleaning solvent may also comprise mixtures of all the above organic cleaning solYents with flu~, u~,al uons such as linear, branched, or cyclic perfluu~u.,a,Lùl~s or hydroflu~,uc.l.Lu..~ or h1d~u~l~lc urlu~lu~,alLùnsoptionally with substituted oxygen, sulfur, ni~rogen,p~ûs~,h~,ous or other halogen atoms attached to a carbon atom and optionally with. surfactant as a ~ agent.
The fluO~u~.a~Lu~ rinse solvent may be selected from the class of hydrofluu~u~a~Lùn or l.~J~ùcl.'~ urlu~ocalLùn compounds or rnixtures c~ .d of linear, branched, or cyclic structures having a boiling point of at least 25C to 120C and such flu~.u~,a.Lùns may be optionally s~hstit~t~d with other functional groups chosen from the class co~ .ti.,~ of other halogens and oxygen, sulfur, nitrogen, and pl Iû~Jl u~ uus atoms The preferred hydroflu~, ucal Lùl, compounds or the WO 94/28196 ~ PCT/US94106004 h~dlu~,lllolu~l~orùcal uOn compounds have a eertain miseibility for the organie eleaning solvents in the boiling range of at least 25C to 1 20C so that at least 2 mole % of the hydroearbon cleaning solvent is miscible with the hydrofluoru~al uol- fluid without obtaining phase S Sl:pal a Lion .
The hydroflu~.oca. Lons praferably contain between 3 to 8 carbon atoms, hydrogen, and fluorine in the eompound. The boiling point is p-u~u-c.uly between 25C and 120C with at least 60 weight pereent fluorine. The compounds ~lu~ulauly have a linear or branched 10 chain.
The present invention provides a Culll,uOailiOI~ for eleaning or removing residual soils or surfaee C~lllal.. .aliùn from a part. The CulllpOailiOI~ col~nie~ a non-~L~.L,upi~ mixture of ll~ul,alb solvent and hydroflu~ru~alL~n solvent. The h~1dlucaluùl~ c~""~one"~
15 is present in an amount of at least 2 weight pûreent based on the total COlll,uuailiùn and is eapable of suL~ y removing the residual soils or surfaee culllalllillaliùn from the part. Th~ hydroflu~,ùca,~on cu""~on_..l has a linear or branehed ehain strueture havirlg 3 to 7 earbon atoms and at least 6û wei0ht pereent fluorine, is eapable of 20 subalalli' 'ly removing any of the l.~J~ùca,L~n cu,u~ ll remaining on the part, and is less eapable than the ll~ùcalLull Cu~pO~ l of subalall~ removing the residual soils or surfaee Culllalllillaliùn from the part.
In eontrast to the eleaning ~ -s of European Patent Publieation 431,458 published June 12, 1991 wherein an aliphatie l~tdl~ ùcc,~Lùn is the "aetive" cu".~-or~,.,l for the removal of the fluxes, fats and oils, and dust, the ~ dlu~.alL
co."~,~n~..l of the present eleaning cu,,.~ ~5 is eapable of suLala..i '~y ramoving the residual soils or surfaee eG..Ia."i,.alion from ~1~33~ ~
a part. The hydrofluoruca,Lo" coi,,u~llellt of the present cleaning .o""uo~;lions has excellent solvency ~llelld~ iCS toward the hy~,ùccl,~ùn co""~u"~"l but has a lesser solvency than the hyd,uca,Lon co"~ "L for the soils or surface c~"l~",;".,Liol~.
Providing tlallllll ' "Iy SUpp~t:,Siùl~ can be ", ,i ,e~ through the use of suitable vapor blanketing species. The rinse solvent may also be selected from compounds or mlxtures c~"",,;s~d of other linear, branched, or cyclic alkyl or aryl alcohols, esters, nitro-, nitrocyclo-, or nitrile compounds, ethers, ketones, hy~ucc~Lûlls, and other non-aqueous media.
Still other objects and ~dvallla~cs of the present invantion will become readily apparent to those skilled in this art from th~ following detailed cla~_,i,ullon, wherein only th~ preferred _,"LA " "~ L~ of the invantlon are shown and describsd, simply by way of illustration of tha best mode c~llt~.ll,ul~lt~.d of carrying out the invention. As will be realized, the invention is capable of other and different 6,1,L " ll~llb, and its several details are capable of ~ o~7s in various obvious respects, all without departing from the invention. Acco~d;l,yly, the drawing and d~s.,li,.,lion are to be regarded as illustrative in nature, and not as 1l : i-.t;./~.
Bri~7f Des~ -7 of Drawinas Figure 1 is a partial s~,ll .n~Lic view of del~ or defluxing en~ that may be used in tl7e multi-solvent non-aqueous cleaning system of the present ill~l~,. n;
Figure 2 is a ~..11 lldt;~. view depicting an dltu.ll~th/~
C.l L ~ .,l of eq~ _.,l that may be used in the present invention;
Figure 3 is a s~ .llali-, view depicting a further ': llaLhe, .,.IIL- " 11_.11 of e71, 1 .,l for use in the present invention;

WO 94128196 ~ j 3 3~ ~ PCTIIJS94/06004 Figure 4 is a partial schematic view of yet further a~ternative equipment for practicing the system of the present invention;
Figure 5 is another ~IllLou;",~"~ of qq~i",e"l for use in the present invention; and Figure 6 is a further el"L-~ "t "I of eq~ i"~"L for use in the present invention.
Best Mode for Carrving out the Invention In its most basic form, the present invention is a novel non-aqueous cleaning process wherebv the most attractive features of the semi-aqueous cleanin~ process and the solvent vapor d~y,aas;~,g solvent procâss are combined. ~ - - ' - ''y, a substrate or part to be cleaned (e.g., a printed circuit board coated with a rosin-based flux, or a metallic or n~ "ic part coated with a petroleum, synthetic, or semi-synthetic based oil or grease) is first washed in a warm or ambient temperature 1~ ~rd~ u~,al Lol~ solvent tending to have a ~reater affinity for the soil or ~u,l~all.;..a.ll on the substrate than a fluo~o.,a.Lùn based solvent. The pârt is then rinsed by spray or i~lllll~.aiùn in a second tank or cleaning region c~"~ a 20 n~l,rla""" ' ' flur.,u~.a,l,ùn solvent, ,GI. c~ aLly having a lower boiling point than the I ., ~: u~,a- Lu. . solvent. The flu~. u~.a- Lu. . solvent has atleast sliqht wlubility for the ~d~o~,a~Lùn solvent and therefors rinses the l,,d~ù.,a,Lùn solvent from the surface of the part. The fluu~ Lu~ solvent is then dried from the part surface by u~à~<JIali 25 in a known manner. The benefit of this process is that drying costs are ",, "i.a~, waste water treatrnent costs and eq~ i, lla~ll and capital ill;. ~II~.lLa are virtually -' Ilillal-.d, and safety of operation is improved. Further, through the use of hydroflu~, u~,al Lùn or perflu~,u~.a,uù~ solvents in the rinse and drying steps, the wo 94/28l96 PCT/US94/06004 ~l 633~1 em,;.un",~:"~dl benefit is greatly improved over the chlorocarbon or chloroflu~,uca,Lon solvent systems.
" The organic c!eaning agent is pl~ralaLI~ a hydrocarbon which may be selected from linear or branched alkyl or alkanol IllOl~ocaluoxylic esters having at least six carbon atoms in the aliphatic moiety and at least one carbon atom in the ester moiety.
The organic ll~ u~,aluùl~ fluid may also be selected from linear or cyclic h~ i~oca,l-ons cu~ ,9 at least one olefinic bond endo or exo to the ring.
The ~ uca~LOI~ may also be pinene and/or c.alllpll_.~e.
The preferrâd hydrofluu, u~al uù"s include compounds of the empiricâl formuia:
CJHnF"n where 1 < n < 4 The three carbon hydroflu~luoalboll~ include tetrafluo(u~,upalles (HFC-254), pentaflu~lo,c~upd.. os (HFC-245), hexaflu~.u,u-u~,a.. as (HFC-236), and heptafluo,op(upa,,~ (HFC-Z27). Preferred three carbon hydrofluon,. a, I,uns include tetraflu~, u,u, u~Jal laa and pentafh,o(u~panes. Tetrafluo.up(u~,a..~ include the following isomers:

HFC-254 isomers CF2HCF2CH, CF,CHFCH3 WO 94/28196 ~ 3~ PCT/U594/06004 Pentafl~u,op,ùpo,,es include the fo~lûwing isomers:
HFC-245 isomers Thr~ preferred hydrofluoru. a,L.ons include linear or branched compounds of the ~mpirical formula:
C~HnFlo.n wh~re 1 < n < 5 15 Th~ four carbon hydroflu~,uu~.,Lùns inciude pentafiuorobutanes (HFC-365), hexafluorobutanes (HFC-356), hepufluorobutanes (HFC-347), octaflyorobutanes ~HFC-338), and nonafluorobutanes (HFC-329).
P~ntafluorobutanes includ~ the following isomers:

CHlCFICHF2)CHF2 Hexafluorobuunes include the following isomers:

CFICH2CH2CFa CFaCH2CHFCHF2 CFaCF2CH2CH2F
-1~ -Wo94/28196 2~B~ PCT/US94/06004 " CHFZCH2CF2CHF2 CHF2CHFCF2CHzF

Heptafluorobutanes include the following isomers:

wo 94/25196 2~L633 PCT/US94106004 Octafluorobutanes include the foiiowing isomers:

(CF3)2CHCHF2 Nonafluorobutanes include the following isomers:

The preferred hydroflu~. uc~ s include linear or branched compounds of the empirical formula:
Cs Hn F12A wherè 1 < n < 6 The five carbon hydroflu~.u.,t..uùl~s include hexafluû~p .~ HFC
476), hePtafl~ U~U~ a~5 (HFC-467), octaflu~.up~ i (HFC-458~, nonflu~.~u,u~ i (HFC-449), decaflu~up~ (HFC-43 10), and undecafluu.u~.~..l....~i (HFC-42~ IU~U~ include the 3 o following isomers:

WO 94128196 ~ ~ ~ 3 3 ~ ~ PCT/US94/06004 CHF2CF2CF2CHFCH, CF ,CF2CHFCHFCH3 2 0 CF3CH2CF2CF2CH, WO 941~8196 '~,~633 PCT/US94/06004 CF3CH2CHFCFzCHzF

CH3CF(CHFCHF2)CF3 Octafluo~o~o~ inciude the ~ollowing isom~rs:

CH2FCHzCF2CF2CF3 WO 941~8196 PCT/US94/06004 ~1~33~1 ~' CF2HCFHCH2CF2CF3 CH3CF2CFzCF2CF2H
s CF2HCH2CF2CF2CF2H

20 CH3CH(CF2CF,)CFI
A most preferred octaflu~,u~ is CF3CH2CF2CH2CF3 which is known in the art as HFC-458 mfcf.

wO 9412~196 ~ 335~ PCT/US94/06004 Nonafluoru~ lles include the following isomers:

CF3CF,CHFCH2CF3 CF3CHzCF2CHFCF3 `

CF3CH2CF2CF2CHFz CF3CHFCHFCF,CHF2 CF,CHFCF2CF2CH2F

CHF2CH(CHF2)CF2CF3 ~i &~
Decafluo,opt~ dl~es include the following isomers:

CHzFCF2CF2CFzCF3 CF3cF2cH2cF2cF3 CHF2CF~CHF2)CF2CF3 U~d-dcafluorùp~d.,l~"~s includ~ the following isomers: ~

2 o CF3CF2CF2CF2CF2H
CF3CF2CF2CFHCF, CF3CF2CFHCF2CF, CHF2CF2CF(CF3~2 The preferrod hydroflu<;,u~,a,Lu,,, include linear or branched compounds of the empirical formula:
C"HnFl~n where 1 < n < 7 The six carbon hydroflu~, u~al L~ls include heptafluo-ul l_ACII l'dS (HFC-587), octafluo,~o~ Aa.,~ (HFC-578~, nonafluo~ Aal~c~ (I IFC-569), WO 94/28196 2~6335~ PCT/US94106004 decafluorop~llal~es ~HFC-55-10), undecafluorohexanes (HFC-5~11), dodecafluo(ol-exa"es (HFC-53-12~, and tridecafluo,uh~a,~es (HFC-52-13). ` .
Heptafluo,~,h6Aàl~es include the following isomers: -CH3CH(CHFCH2CF3)CF3 Octâflu~lOl~e,~al,~ include the followin~ isomers:

CH2FCHFCH2CFzCHFCF3 CH3CF~CF2H)CHFCHFCF3 CH3CF2CF(CF3)CF2CH3 Nonafluu,vl.~ a,~ includ~ the following isomers:

CF3CH2CH2CF2CHFCF, CF3CFzCH2CHFCH2CFJ
CFlCHFCHFCHFCHzCF3 CF3CHzCFzCHFCH2CF3 ~ 633~1 CF3CHFCHzCF2CH2CF3 ICF3CH2)2CHCF3 15 CF3CH2CF2CHFCHFcHF2 20 CF,CF2CHFCHFCHFCH2F
CF,CHFCF2CHFCHFCH2F
CF,CF2CH2CF2CHFCH2F
CH3CF~CF,)CHFCHFCF, CF,CF2CHFCH2CHFCHF2 WO 94/:Z8196 ~ ~33~ PCTIUS94/06004 CHF2CHFCF2CHFCHFcHF2 CHF2CF2CHFCH2CF2cHF2 CH2FCF2CF2CF2CF2CH, WO 94/28196 ~ 1 6 3 3 ~ ~ PCT/US94/06004 CF3CF2CH2CH2CF2cHF2 CF3CHFCHFCH2CF2cHF2 CF3CH2CF2CH2CF2cHF2 CF3CFzCF2CF2CH2CH3 15 CF3CHFCFzCFzCHFCH3 '`' ' CF3CF2CF2CH2CF2CH3 CF,CH2CF2CF2CF2CH3 Decaflu~.,u~e.,l...,~s include the following isomers:

~6~

CF3CH2CF2CF2CH2CF3 ;, CF3CF2CF2CHFCH2cHF2 CF3CHFCF2CF2CHFcHF2 CFsCHFCF2CHFCHFCHF2 .

WO 94/28196 ~ ~ & 3 3 ~ ~ PCT/US94/06004 CF3CFzCF2CF2CH2CH2F

CF,CF2CF2CF2CHFCH3 CHF2CF2CHFCHFCF2cHF2 WO 94/~8196 S~ PCT/US94106004 CF3CHFCF2CF2CF2CH3 '.
S
UndecafluorolleAd,les include ~he following isomers:
HFC-5~1 1 CH3(CF2)4CF3 CH3CF(CF3)CF2CF2CF3 (CF3)2CHCH2CF2CF3 CH2FCHF(CF2)3CF3 CH2FCF2CHFCFzCF2CF3 CH2F(CF2)3CHFCF3 CF2HcH2(cF2)3cF3 CF2HCHFCF2CHFCF2CF, CF2H(CF2)3CH2CF3 Wo 94/28196 PCT/US94/06004 ' CF3CHFCF2CHFCHFCF3 CH2F(CF2~"CF2H
CF2HCHF(CF2)3CF2H

A preferred undecaflu~,uh~,~a"~ is (CF3)2CHCH2CFzCF, which is known in the art as HFC-5~11 mmzf. Dod~cafluû~o~,~Aa,,~include the following isomers:

CF3CFzCHFCHFCF2CF3 CF3CFzCF2CH2CF2CF3 CF3CF2CHFCFzCHFCF3 CF2HCF2CF2CF2CF2cHF2 .

wo 94/28196 2 ~ 6 3 3 51 PCT/US94/06004 CHF2CF2CH(CF3)CF2CF3 (CF3~2CHCFHCF2CF3 A preferred dodecafluorohexane is 5 (CF3)2CHCHFCF2CF3 which is known in the art as HFC-53-12 mmze~ Tridecaflu~,uh~,~a~es include the following isomers:

CHF2CF2CF(CF3)CF2CF3 Other preferred l~ldlu'' ~o,u-....l,o"s include linear or branched compounds of the empirical formula:
C,HnF where 1 c n 5 8~
2~ ne"~ L~Li~ xamples of this class are:

CH3(CF215CH3 CH3CH2(CF2)"CF3 CF3CH2CH2(CF2)3CF3 CH2FCF2CHF(CF2)3CF3 CH,CH2CH2CHFCF(CF3)2 WO 94~28196 ~ ~ 6 3 3 51 PCT/IJS94/06004 CH3CH(CF3)CF2CF2CF2CH3 - CH3CF(CF3)CH2CFHCF2CF3 CH3CF(CF2CF3)CHFCF2CF
CH,CH2CH (CF3)CF2CF2CF3 - 5 CHF2CF(CF3) (CF2)3CHF2 CHF2CF(CF3)(CF2)3CF3 Other preferred hydrofluo(uca.bùns include linear or branched compounds of the empirical formula C8HnF where 1 < n s 9.
Re~ us~ th/~ examples of this class are:

CH3~CF2)~CH3 HCF2(CF2~CF2H
CF3(CF21~sCF2H
CHF2CF(CF3)(CF2~,.CF3 CH,CH2CH(CFI)CF2CF2CF2CF2 CH3CF(CF2CF3)CHFCF2CF2CF3 CH3CH2CH2CHFC(CF3)2CF3 CH3C(CF3)2CF2CF2CF2CH3 CH3CH2CH2CF(CF3)CF(cF3)2 CH2FCF2CF2CHF(CF2)3CF3 The hydrofluu,u.,a.Lùn cc,,..pùn6..L may also be an a~ul~u~
mixture of hydrofl-,o,uca,L~n and another cu.l.~Jùl~ L as long as the mixture is capable of suLalall 'Iy removin~ any - 25 ~ uca~L~ co...pon_.,l remainin~ on the part and is less capable than the l~t91u~.~lLùl~ -",un_..l of ~ removing the residual soils or surface COIIlal.l Idt;.a.~ from the part. Examples of preferred d~Jll" mixtures include CF3CH2CF2CH2CF3 and one of the followin~ c~ ull_.ll~. methanol, ethanol, ;su~JIu~a~lul, n-WO 94~28196 PCT/US94106004 21~33~1 propanol, t-butanol, isobutanol, n-butanol, t-amyl alcohol, u, u~ lene, and p~, ~l ,lo- o~ ll ,ylene.
Figure 1 is a partial s.llt~lllali., illustration of one type of ~.
apparatus which can be used in the present process. Therein, a vessel (10) is divided into three sumps: a cleaning sump 15, a wash sump 20, and a rinsing sump 25. The cleaning c~lll,ualllll~lll 15 is separated by one or more walls 17,19 from the second COIll,ual ~ 11l 20, which contains a flu~.ùcaluon fluid 22 heated to its boiling point by a heater 34, to provide a r.ul.rla..ll.laL,l_ 10 condarlsi"g vapor blanket 30 or a flallllll ' ~ Su,u~ aiul~ blanket over all the sumps 15, 20, 25 common to vessel 10. C~..l,uallllle~
20 also provides an area where the bulk of the soil and organic cleaning agent can be washed from the substrate by either illll~l~.aill~ into the fluofoca.uùn fluid contained in cu~llual ll.lt,.ll 20 15 or by ,c la~ . l lv. l l in a spray stream 18 of pure fluo~ocal Lùn colldf rl .a~t" whereby the Cul~t....l I ~ ~ liquid drops into the sump below. The clsaning Cu~,ua~ ..l 15 is adapted to contain a body of the organic cleaning solvent 24 tailored for the cleaning 3~ iùn, which could be an organic ~ u.,a.Lon as noted above 20 and in the examples below for heavy duty cleaning. or a mixture of an organ~c l l, J~ u.. . Lvl I with a milder solvent such as a fluul u~.al uu for less ri~qorous cleaning ~ s ~where Cu,ll, ' ' ~y with the substrate may be of more important co~ u~a~iùn)~ The washing CG..~ .. t~ .ll 20 is adapted to contain a rinsin~ a~ent 22 having at 25 least sli~ht solubility for the cleaning solvent 24. As used throughout this sr~ , "slight solubility" of the rinsing flu~lu..alL.ull solvent for the l ,~l~. Lùl) cleaning solvent Is defined as havlng 2 2 mole % of the ll~.' ucaluùn is soluble in flu~lucalL
solvent. An l~, up~ i t~. rinsing agent 22 and one preferred in the 36~

Wo 94/28196 ~16 3 3 ~1 PCT/US94106004 present invention is a fluo~ ucal Lon based solvent as noted above and in the examples below. Optionally, a second rinsing colllpal LIII~IIL 25, which is at a cooler temperature than C~ palLllla,~ 20, may be provided dO~ a"~ from the first rinsing 5 colll~JalLIll~l~l 20, and is also adapted to contain the fluolu~all~ol~
solvent rinsing agent. The purpose of COIIl,l)a~ llL 25 is to provide a final ;~ ..a;ùn rinse for the subsuate to remove trace residues of soil or cleaning solvent and also to cool the substrate so that the part is rinsed with pure condensing vapor in the vapor zone 30. The 10 vapor zone 30 is formed above the ~ ,u6~;1iie COIll,ual Llll~
15,20,25 and a cooling coil 32 of a type known in the art (such as disclosed in U.S. Fatent 4,261,111 to Rand) defines the u,uu~,,,,u~L
extent of the vapor zone 32 to condense vapor for return of cOl)d.3.~al~ to c~""~.., I,,,t,,,L 25.
It is to be noted that the ll~J~ùcalLùl~ cleaning solvent 24 and fluoru~aluoll rinsing fluid 22 may be chosen for their respective mutual ' ~ ' such that some means of physical r~"Jalaliùll such as phase ~palaLIul- may be ~mployed to remove built-up soils as well as to recycle clean organic solvent back to its o, ;~ ,.,Li"g sump.
20 Therefore, with reference to Figure 1, it is to be noted that a U-tub~
phase separator (not shown) or weir or skimmer may be used in conjunction with colllpal llll_.ll 20 to separate or remove cu"d~ns~
II~J~ucall,ull which will float on top of the fluûlu~aluùnl and this ~ ~, aLiun device (not shown) may be arranged so that the excess 25 lltJlu;:alLu~l fluid will flow back to the cleaning tank 15 from the rinsing tank 20.
The vessel 10 of Figure 1 is depicted as an open top type of defluxer or drJu,~ _.. However, it is to be ull~..aluOd that the vessel 10, in its 5~ L;~, forrn may also cl lal ~ , an i~-line .

-Wo 94/28196 21~ 3 3 51 PCTiUS94/06004 type of degreaser or defluxer wherein conveyor means (not shown) may be used to succeOa;~ly convey the parts from the cleaning sump 15 to the rinsing sumps 20 and 25.
In Figure 2, the organic cleaning fluid in cleaning tank 15 may 5 optionally be mixed with a fl~oror .,,uù,~ type solvent. The cleaning fluid in this case would be warmed to a sufficlent temperature to boll off the fluu,ùca,u~n, where the boiling point of the fluorocarbon should be at least 10C. Iower than that of the organic l~ u~ uon fluid. The mixture is heated with coils 33 so that the resulting vapor 10 zone 30 ;llllll~liatuly overlying the h~JIu~ L.ù,l is essentially a flu~,u~ a,l,ùn-based l~o,~rla".... ' ' or ~lalllll ' "~y suu~.,..~.D;~n vapor zone to minimize the possibility of explosion. The cleaning fluid mixture may or may nût require a surfactant additive to ensure phase l~u~l~uy~ y between the organic ll~lu~ alLul~ and the 15 flu~luualLùn solvents. The flu~lu~ alLo~ which was boiled off would be ~ d ât a constant conc~"t aL;ù,~ in Cu~ Ja, Llll~ 15 by either rsturning the vapor Cul~ Oa~l~ back to this Cu~llual ~",~ ~L
and/or pumping fluid from the rinse Cull~Jal L~ L(a) 20,25 back to this sump throu~h control with a volume or level-sensing transducer 20 (not shown). In this variation of Figure 1, the boiling rinse sump 20 mây nût be necessary, or it could function purely as a second rinse sump at any i" ". ' temperature between Cul,l~Ja. Ll~ L 15 and cu".. Ll"~ 25. In the three-sump option where sump 20 supplies the fluu~u~.a~Lu~ vapor tû form the n~(la~ aL.I~ blanket for vessal 25 lO, sump 20 maV be heated with heating coils 34 and heating coils 33 may not be necessary. In the two-sump option where sump 15 supplies the fhJ~Iu~.alLul~ vapor tû form the nu"rla"",. '~ blanket 30 for vessel 10, heâting coil 33 would be preferred and heating coil 34 may not be ne c ~ . In the twû-sump option where sump 15 wo 94/28196 ~ 6 3 ~ ~ ~ pcTruss4/o6oo4 supplies the fluolucalv~l~ vapor to form the nonrla~ labl~ blanket 30 for vessel 10, sump 20 may not be necessary and sump 25 would provide a c! liquid rinse ill~ aiùl~ prior to bringing the cleaned substrate into the vapor cùlldel~aillg zone 30 for a final pure 5 colldensa la rinse.
In Figure 3, the rinse sump 20 may contain a saturated solution of the h~1J~ucalL.OIl based cleaning fluid and the fluv~ucalbvll based rinsing solvent. The fluids are selected so that the hyv~uca.von phase separates at some low collc~.,l.c.tian (i.e., 10 ~ess than 10 mole %) in the flu~,uca.Lon and floats to the top of the more dense fluvlul,alLvl~, providing a c~---' ,y effect back into the cleaning sump 15. The rinse sump(s) 25a or 25b may also in turn cascade pure rinse solvent into sump 20 to maintain its level and also to " .,_I;u,, ''~ provide a flow skimming action to sweep the 15 separated organic layer towards the boil sump 15.
In Figure 4, the boil sump 15 contains both hy~ucalvùl~ and fiuv,u.,a~Lvn based solvents of sufficient i" ' '- ~/ to form layered cleaning zones 15a and 15b. The avv~.lla~a6 of this alla.,~, ,l is that the heating coil 33, which provides the 20 ~v"tla." ' ' vapor blanket for vessel 10, is now immersed in a fluv(ucalvûll rich phase which lessens the ,~r ' ~y of dC~ C.IIal fire if the liquid in the sump drops below its intended level.
hJIlll.,.lllula, the boiling fluvlu~,albull liquid now provides an agitabon actbon to the top less dense organic I.1l~u~.a.Lùn phase to 25 assist in the cleaning ~.rv..,,a,~ce. As in Figure 3, the fluvlucarvù
rinse solvent and the ~l~dlu~.al Lvn cleaning solvent can be cascaded or pumped back to their .~ _lh~.~ sumps to ensure that sump liquid Yolumes are ., ~ed.
In Figure 5, the ll~d~u~r~bol~ cleaning zone 15 may be Wo 94n8196 2 ~ 6 ~ 3 ~1 - PCTNS94/06004 separated from the rinsing zones 20 and 25 by being provided within separate structures 11 and 12. This configuration is intended to provide the ability to retrofit conventional solvent vapor d~,Oaail,g or defluxing batch-type eql~i"IOII~ such as ~O,ulOaonlod by vessel 12 5 in Figure 5 with the cleaning process of this invention. The carry-over of organic solvent from vessel 11 to vessel 12 can be reduced by Illecl,all ' devicss such as an air knife 37. Nitrogen or any other nollrlal,,,,l ' ' culll,u,,,~s~d gas may be introducad into the vapor zone overlying the hy.l,ul,alLon sump 15 to reduce 10 h~d~uca~bù~ rla",l,l ' "~y or the danger of explosion, as typical with many types of c~"J_.,Iiùl~àl ssmi-aqueous (organic cleaning/aqueous rinse) cleaning ~uuo.~:.3~5. in the fluo~ù~a~Lùn boil sump 20, the residual ll~ u~,a~LJù~) carried over from cleaning sump 15 may bô
a~ separated out as described in Figure 1 and recycled 15 back with a pump 45 (as ~.I, "y depicted) in view of the physical Soua~ - ~ of the two clOaning zones which would prevent ~s~- ' ,9 as in the previous u."L ' "_.~La.
In Fisure 6, it is presumed that the organic cleaning solvent in cleanin~ sump 15 is ;~ ' ' '~ or of low miscibility with the 20 flu~,u.,a,L,ùn-based rinsins solvent in rinsing sump 25. To prevent mixing of these solvents together and thOreby ,~
.Gull Id~ 9 the cleaned substrate, the flrst rinsing zone is provided with a coupling solvent (such as an alkanol like butanol, or another fluulu~ .al such as triflu~,uh..~.~nO, or any other type 25 of l.~l~uca~bOn) wherein th~ rluu,o~,a,Lùn solvent is miscible with the coupling solvent. rJ'~fu.dl,l~, the flu~,. Lùn solvent has a lower boiling point than either the organic cleaning solvent or the coupling solvent. In this case, the flu~, uca~ Lu,~ in sump 25 primarily sOrves the purpose of bla~ll~ti~lg the fla~ ' liquids in sumps 15 WO 94128196 ~ PCT/US94/06004 and 20 with a no,lrla""l,aLI~ vapor, and the level of liquid in rinse sump 20 which is c~"~urised primarily of coupling solvent is " ,i ,ed by makeup with fluGluc~,uo,~ liquid from sump 25. The substrate which has been rinsed in coupling solvent sump 20 is 5 either subjected to a final i"""~,c.ion rinse in sumps(s) 25a andlor 25b or is held in the flu~,u, a,b~n co"dr,~ .i"g vapor zone 42 for a final rinse, which can be suitably accr.", ' h~d since the coupling solvent is miscible with the fluo-.,c~,l,ù~ solvent.
FXAMPI F~
The following examples are used to d~."or,~L,a~ the ad cleaning p~, ru""anc~ observed when a soiled coupon is first immetsed in an organic cleaning solvent followed by a rinse with a fluul u~ al solvent. In these studies, stainless steel coupons were coated with various Cullllll~luidl petroleum, semi-synthetic, and synthetic oils. The collllll~cial petroleum oils are pal.,rri,~ ctraight or branched chain saturated ~ ùclLùl~a. All of these oils are used in the ll-ut~ .ulki"~ industry for cooling and iubricating purposes. The synthetic oils contain synthetic polymer with additives cr,": ,9 fatty acids and amines. The semi-synthetic oils are mixtures of the petroleum and synthetic oils. The eleaning process used for tests to d_..,~ l. this invention consisted of 30 second ;"~,_.s;on of a coupon in the organic elsaning solvent followed by a 30 second ;~ _.ai~ in me 25 flu~u"ll_.~ .l solvent and a 30 seeond rinse above the liquid in the eooling eoil zone with the co~ g vapors of the fluolu. I~ i- dl solvent. The amount of soil on the coupon before and after cleaning was 'et ~- I_d with a c~ .idl CO2 eo~ ,t~.., whieh measures ~o ~ u~ a,~ iJ;ty the amount of organic rasidue, e~ 3id in ~33~
carbon units, on a surface. The sample of residue on the coupon i5 introduced into a combustion furnace via a sample boat, and is combusted in oxygen ~I,,,r,a,uh~,~ at a temperature of 650C. The resulting COz and other combustion products pass through scrubbers to remove any i"L~, r~, i"g halogens, sulfur, nitrogen oxides and water. The gas then passes to the r~o~ 6h~ cell which contains an indicating solution. As the gas stream passes through the solution CO2 is quantitativelv absorbed, and reacts with a chemical in the solution to produce a titratable acid. An electric current is then auLu,,,at 'ly adjusted to neutralize the solution, the total current is i,.t~ t~,d, and the results displayed as ,,;u,uu,~,,,,s of carbon. The sensitivity of this method is +/- 0.01 ~ uy~a~
carbon, which is one of the most sensitive methods to reproducibly analyze carbon cu~".ùr.~ on a surface. Since all oils cleaned in this invention are primarily organic in nature, the ~u~iLu~ y of carbon content is an excellent way to determine with high reproducibility and sensitivity the amount of organic soil on a substrate.
2 0 Fy~rnDle One A (C" to C") methyl ester is used as the organic solvent.
S~_Llu~copi~ cl~ t i~liùn indicated a small quantity of a branched CGI~ u-~l-L. HFC 52-13 is a branched hydroflu~.ul;~.,uu.~
(C~F"H) used as the fluu.u~,~.Lon rinsing agent. The methyl ester is effective in removing petroleum based oil from metal coupons at room temperature, but a thin film of the methyl ester solvent remained after the cleaning process. The oil is not abie to be cleaned from the surface of the coupon by HFC 52-13. However, fhO pA~c~S~ of clooning Wifh tho m thyl o~lcr, rin~in~ wi h HFC 5:!-* wo 94n8l96 ~ ~ 6 3 3 ~i 1 PCT/~JS94/06004 13 followed by a rinse by the fluo-uca~on condel,~i"g vapors was highly effective in removing greater than 99.g% of the thin film of high boiling ester from the metal coupon without leaving a measurable trace of oil C~llL~ .lalll. Effectiveness of cleaning was 5 assessed by weight measurements. In each of the examples below, blank coupons were d.~l~lllli.l6d to contain about 10 ug carbon on tha surface.
FY~rnDle Two A dibasic ester cieâning solvent mixture was prepared in the laboratory by s~,LI,~ ,,-g thr~ dimethyl esters of adipic acid, succinic acid, ând glutaric acid in the plupGI liul-s of 10 wt%/22 wt%/68 wt%, ~ ?~ /uly. Soiled coupons were immersed in a mixturâ of the dibasic esters with HFC-365 (CF3CH2CF2CH3) ât 56 C
for 30 seconds, followed by â 30 second ;,~"~ ,iol~ in HFC-365 at ambient temp~râture and â 30 second vapor rinse with HFC-365.
The following results were noted:
Expt. Oil on Substrate Cleaning Method 1~ uy~ lla (ug) Carbon on the Surfac~
~efore After Cleaning Cleaning 25 (a) ,: ~ ' this invention 819 11 ~b) petroleum no HFC rinse 819 495 (c~ petroleum no ester rinse 819 70 (d) synthetic this invenbon 508 10 (e) synthetic no HFC rinse 508 724 3s (f) synthetic no ester rinse 508 499 2~3~1 .
In the eA~Jtl(i~ll~lll~ with the petroleum and synthetic oils, using anorganic cleaning step followed by a fluo,ul~l~e,,,ical vapor rinse step resulted in co"",l~t~ly cleaning the coupon surface (>99.9% .
removal of carbon~. However, in aA~,~,i",~"L~ (b) and (e), siy"iri~
5 amount of carbon remained on the surface when the coupon was cleaned by a 30 second i"""~r~;on in dibasic ester only followed by a 30 second drying in air without the HFC vapor rinse. In ex~.e"i",~"l:. (c) and ~f), ~;~",;ri~ ~,"L amount of carbon residue remained on the surface when the coupon was cleaned by a 30 second ;"""~,~;ol- in HFC-365 followed by a 30 s~cond drying in air without using the ester eleanin~ step. This example c:~."o" ,l,"L~s that a flu~lu,,l~lll;c~l vapor rinse step is required to C~ v clean a soiled surfaee whieh has been immersed in either a dibasie ester or a mixture of a dibasie ester with fluu~u~ l, and neither the 15 ester alone nor the fluu~ocln~ .al solvent alone is suffiei~nt to c~" ' t~.ly elean the surfaee.
FY~rnDle Three Soiled eoupons were immersed in a 50/50 volume % mixture 20 of c~ A."-~n~. a eyelie keton~, and HFC-365, a hydrofluo-roearbon, for 30 seeonds at 57-59C followed by a 30 second ;,.""~.,.;~n in HFC-365 at ambient temperature and a 30 second vapor rinse with HFC-365. The lFollowing results were noted:

wo 94/28196 PCT/US94/06004 ~1~3351 Expt. Oil on Substrate Cleaning Method M: uylallls (ug~Carbon on the Surface Before After Cleaning Cleaning (a) petroleum this invention 819 8.7 (b) petroleum no HFC rinse 819 1064 (c) petroleum no ketone cleaning 819 70 (d) synthetic this invention 508 7.7 (e) synthetic no HFC rinse 508 1475 (f) synthetic no ketone cleaning 508 499 lg) mineral oil this invention 950 7.5 (h~ synthetic this invention 1033 14.9 In the ~A,u_.i~l_.lla (a) through (f) using an organic cleaning step 25 followed by a fluolu.,ll_.llicdl vapor rinse step resulted in Col", ' 'y cleaning the coupon surface (>99.9% removal of carbon).
However, in ~ a (b) and (e), ~.iu"iri~.~",l amount of carbon remained on the surface when the coUpon was cleaned by a 30 second i~ .aiull in c~ ulle only followed by a 30 second 30 drying in air without the HFC vapor rinse. In ~A~ a (c) and (f), ~iul- Il amount of carbon residue remained on the surface when the coupon was cleaned by a 30 second ill~n~a~ in HFC-365 followed by a 30 second drying in air without using the ketone cleaning step. This example d~..llOIlal~ that a ~luo,u~ .";~ a 35 vapor rinse step is required to c_..., ' ~y clean a soiled surface which has been immersed in eith-r ketone (cyclic or acyclic) with WO 94/28196 ~ 1 6 3 3 5 ~ PCT/US94/06004 fluo,u~ ,,,ical, and neither the ketone alone nor the fluorocl~e",;~ al solvent alone is sufficient to c~",~J!ut~'y clean the surface.
Exam~l~ Four Soiled coupons were immersed in a 50/50 volume %
mixture of liquid cV~lo~ .a~ol, a cyclic alkanol and HFC-365, a hydroflu~ocO,Lon, for 30 s~conds at 57-59C followed by a 30 second il,...,~ in HFC-365 at ambient temperature and a 30 second vapor rinse with HFC-365. The following results were 10 noted:
Expt. Oil on Substrate Cleaning Method ~ ' u~. .." ~:, (ug~
Carbon on the Surface Before Aner Cleaning Cleaning (~) petroleum this invention 819 4 (b) petroleum no HFC rinse 819 2397 (c) petroleum no alkanol cleaning 819 70 (d) synthebc this invention 508 139.7 (a) synthetic no HFC rinse 508 1148 (fl synthebc no alkanol cleaning 508 499 (9~ mineral oil this inv~ntion 950 12.7 (h) synthetic this invention 1033 10.2 Wo 94/2X196 ~ 1 ~ 3 3 a 1 PCT/US94/06004 In the e,.~,eri,,,e,,lb with petroleum oil, using an organic cleaning step followed by a fluo,ocl,c",;cal vapor rinse step resulted in colllple~
cleaning the coupon surface ~>99.9% removal of carbon). Since cyclohexanol is a fairly poor solvent in cleaning synthetic oil, as shown in ~ lilllenL~ (b~ and le), most of the oil and the organic solvent film was able to be removed with the cieaning process of this invention as shown in e~ lilllell~ (d). AddiLiun "y, in .i",_.,l:. (b) and (e~, a s;~,.iri. a"l amount of carbon remained on the surface when tha coupon was cleaned by a 30 second illllllel~idl~ in c~ h_,~ ol only followed by a 30 second drying in air without the HFC vapor rinse. In ~ J_.illl6llla (C) and (f), Si~,iri~a~l amount of carbon residue remained on the surface when the coupon was cleaned by a 30 second illllllt~laiun in HFC-365 followed by a 30 second drying in air without using the alkanol followed by a 30 second drying in air without using the alkanol cleaning step. This example d~..llvllal~t~.~ that a fluv.v,.l,_...;~ al vapor rinse step is required to ~ ' I 'y clean a soiled surface which has been immersed in an alkanol (cyclic or acyclic), and neither the alkanol alone nor the fluo,v..l.~...ic~l solvent alone is sufficient to cv". t. ly 20 clean the surface.
Example Fiv~
Soiled coupons were immersed in a 50/50 volume % mixture of liquid 1,-5- " ..ull.~llcy~'~o .~, a cyclic olefin, and HFC-365, a hydrofluv,oc~.vdn, for 30 seconds at 57-59C followed by a 30 second i.. _.~idn in HFC-365 at ambient temperature and a 30 second vapor rinse with HFC-365. The following results ware noted:

~63351 Expt. Oil on Substrate Cleanlng Method ,~ uylalllS ~ug~
Carbon on the Surface Before After Cleaning Cleaning (a) petroleum this invention 819 10.1 (b) petroleum no HFC rinse 819 2953 (c) petroleum no olefin cleaning 819 70 (d) synthetic this invention 508 18.8 (e) synthetic no HFC rinse 508 2831 (f) synthetic no olefin cleaning 508 499 (9) mineral oil this invention 950 10 Ih) synthetic this invention 1033 15.1 In the ~Au_.i~ llla with petroleum oil and synthetic oil, using an 25 organic cleaning step followed by a fluGIu.,l~ l;.,cll vapor rins~ step resulted in ,u~ cleâning th~ coupon surfacu (>99.8%
removal of carbon). Howev~r, in ~A~ J~lla (b) and (e), aiy"iri.,~"
amount of carbon remained on th3 surface when the coupon was cl~aned by a 30 second i~ a;ùl~ in 1,5 ' "~.thtl~ o " ~e 30 onlv followad by a 30 second drying in air without the HFC vapor rinso. In t, i It~. (C) and ~f), siyl~ ~ 1l amount of carbon residus remained on the surface when the coupon was cleaned by a 30 second il~ a~aiull in HFC-365 followed by a 30 second drying in air without using the olefin solvent cleanin~ step. This example 35 du.~lullaLI.~t~ that a fiuo,u~.l,_.ll;~.~l vapor rinse step is required to c~., ' I '~ clean a soiled surface which has been immersed in an -4~-WO 94/28196 ~ 1 ~ 3 3 5 ~ PCT/US94/06004 olefin (cyclic or acyclic), and neither the olefin alone nor the fluo,uclle",;~l solvent alone is sufficient to c~",, '~t~,ly clean the . surface.

5 E Y:~'IlDIe Six Soiled coupons were immersed in a 50/50 volume ~0 mixture of liquid benzotrifluoride, a fluorinated aromatic chemical, and HFC-365, a hydrofl~o~u~a, u~ll, for 30 seconds at 57-59C followed by a 30 second illll~l~la;ol) in HFC-365 at ambient temperature and a 30 10 second vapor rinss with HFC-365. The following results were noted:
Expt. Oil on Substrate Cleaning Method ~ uyl al, la lug) - Cârbon on the Surface Before After Cleaning Cleaning (a) petroleum this invention 819 13.3 (b) petroleum no HFC rinse 819 138 25 ~C) petroleum no fl. org. cleaning 819 70 (d) synthetie this invantion 508 16.1 (e) âynthetie no HFC rinâe 508 1022 (fl synthetic no fl. or~. eleaniny 508 499 (~) minerâl oil this invantion 950 13.7 35 (h) synthetie this invention 1033 127.9 wo 94/28196 PCT/US94106004 ~1633~1 In the e~u~:,i",~"l~ with petroleum oil and synthetic oil, using an organic cleaning step followed by a fluGruch~,,,ical vapor rinse step resulted in c~""~lut~.~/ cleaning the coupon surface (>99.8%
removal of carbon). However, in elAUelilll~ > (b) and (e), Siu~iri~
amount of carbon remained on the surface when the coupon was cleaned by a 30 second i"""~(:,io~ in benzotrifluoride only followed by a 30 second drying in air without the HFC vapor rinse. In experi-ments (c) and (f), Siy,,;ri,,c,,,l amount of carbon residue remained on the surface when the coupon was cleaned by a 30 second i"""~,~;on in HFC-365 followed by a 30 second drying in air without using the flu~oa~ lal;~. cleaning step. This example d6~1~0~
thât a fluon,~.l,_.,.;~ dl vapor rinse step is required to cu,,,~ uly clean a soiled surface which has been immersed in a fluorinated aromatic solvent, and neither the fluu~u~u~ t;_ cleaning solvent alone nor the flu~lu~l,_., solvent alone is sufficient to cu,,,~lutuly clean the surface.
EY~rnDle Seven Soiled coupons were immersed in a 50 volum~ % mixture of pUly-~lltlu~l~ glycol (MW 200~(a polyether diol~ and a methyl ester, and 50 volume % of HFC-365, a hydroflu~,uc..~L~nr for 30 seconds at 45-50C followed by a 30 second i..""_.:.;ùn in HFC-365 at ambient temperature dnd a 30 second vapor rinse with HFC-365.
The following results were noter~:

Wo 94/28196 ~16 3 3; 1 PCT/uss4/06004 Expt. Oil on Substrate Clesning Method Micrograms (ug) Carbon on the Surface Before After - Cleaning Cleaning (a) petroleum this invention 819 14 10 (b) petroleum no HFC rinse 819 1917 (c) petroleum no PEG/ester cleaning 819 70 (d) synthetic this invention 508 11 (e) synthetic no HFC rinse 508 1847 (f) synthetic no PEGlester cleaning 508 499 (~) mineral oil this invention 950 12 (h~ synthetic this invsntion 1033 13 in the ~A,V~ lla with petroleum oil and synthetic oil, using an 25 organic cleanin~q step followed by a fl~u~ alll;cal vapor rinse step r~sulted in c , ' 'y cleaning the coupon surface (>99.8%
removal of carbon). However, in ~ .i",~ s (b) and (e), si~"ir,ca"
amount of carbon remained on the surface when the coupon was cleaned by a 30 second i""" .si~n in ~ol~utl,/l~ glycol/methyl 30 ~ster solvent mixture only followed by a 30 second drying in air without the HFC vapor rinse. In aAp~,.ill._.lla Ic) and (f), a;~liril,alll amount of carbon residue remained on the surface when the coupon was cleaned by a 30 second i,,,,,.~..siu,, in HFC-365 followed by a 30 second dryin~ in air without using the glycol/ester solvent 35 cleaning step. This example d~,.llulla~ t~ that a fluofucl, ., vapor rinse step is rQquired to cu.l, - ~y clean a soiled surface wo 94/28196 PCTIUS94/06004 21~33~1 ~
which has been immersed in a mixture of glycol with an ester, and neither the mixed organic solvent alone nor the fluo,u~,h~,,,i.,dl solvent alone is sufficient to c~ Jt~ ly clean the surface.
ExamDle Eiaht Soiled coupons were immersed in either a methyl ester, or a mixture of polyethylene glycol (MW 200)(a polyethsr diol) and a methyl ester, for 30 seconds at 57-59C followed by a 30 second i"""~,:,iu,l in either HCFC-123, a ~/d~u~ lu~urluu,u~a~l,on~ or HFC-52-13, a highly fluorinated alkane, at ambient temperature and a 30 second vapor rinse with either flu~lvul~"~;ual solvent. The following results were noted:
(a) The synthetic oil and the grease Valvoline were both ramoved from metal coupons to better than 99.9% using the PEG-200/methyl ester cleaning solvent mixture with HCFC-123 as the rinse solvent in the process of this invention.
(b) Same as (a) with 123 replaced by HFC-52-13 which is (CF3)2CHCF2CF2CF,.
2 o FYA~nDle Nine Soiled coupons were immersed in a 50/50 volume % mixture of BIOACT EC-7, a cu~,~". .~ l blend of terpenes and nonionic surfactants, and HFC-365, a hydrofluu~u.,a~L.u~, for 30 seconds at 57-59C followed by a 30 second ;,....~ ;ùn in HFC-365 at ambient 25 temperature and a 30 second vapor rinse with HFC-365. The tollowinll ros~lts wors nots 6 ~16 3 3 5 ~ PCT/US94106004 Expt. Oil on Substrate Cleaning Method M;l Oylalll~ (ug) - Carbon on the Surface Before After Cleaning Cleaning la) petroleum this invention 819 15.3 10 (b) petroleum no HFC rinse 819 2221 (c) petroleum no terpene cleaning 819 36 (d) synthetic this invention 508 13.6 (e) synthetic no HFC rinse 508 2272 (f) synthetic no terpene cleaning 508 27.9 20 (g) mineral oil this invention 950 12 (h) mineral oil no terpene cieaning 950 94 (i) synthetic this invenbon 1033 13 a) synthetic no terpene cleaning 1033 340 In the ~A~ n~ a with petroleum oil and synthetic oil, using an organic cleaning step followed by a flu~,u~ ,dl vapor rinse step 30 rr~sulted in virtually complete cleaning of the coupon surface (>99.696 removal of carbon). However, in ~A~ (b) and (e), ~iu~iri~n~l amount of carbon remained on the surface when the coupon was cleaned by a 30 second ;",.,.~.:,;..,~ in the terpene solvent mixtur~ only followed by a 30 second drying in air without 35 the HFC vapor rinse. In ~ .;".- .,t~ (c) and (f), s;~" ' ,l amount of carbon residue remained on the surface when the coupon was cle~ned by a 30 second ;.~ ,;on in HFC-365 followed by a 30 WO 94/28196 21 S 3 3 ~1 PCT/US94106004 second drying in air without using the terpene solvent cleaning step.
This example cl~i"on~l,alt,s that a fluOIuc~l~nll;~al vapor rinse step is required to culll~,luL~ly clean a soiled surface which has been immersed in a terpene solvent, and neither the terpene solvent alone nor the fluO(OCI-~illl;.,al solvent alone is sufficient to c~"",ul~t~ly clean -the surface.
FYs~ Dle Ten Soiled coupons were immersed in 50/50 volume % mixture of liquid cyclo~,~Aanona, a cyclic ketone, and HFC-365, a hydrofluo-rocarbon, for 30 seconds at 56-59C followed by a 30 second i"",. .aion in a nu"tla""" ' ' constant-boiling blend of 5% HCFC-141 b, a l"~l~ù~ utlu~u~,albol~, and 90% HFC-365, a hydrofluo-rocarbon, at ambient temperature and a 30 second vapor rinse with the cul,da,~i"g ~ul~ ui~ vapors of HCFC-141b/HFC-365. The following results were noted:

WO 94/28196 ~ 1 ~; 3 3 ~1; PCT/US94/06004 E%pt. Oil on Substrate Cleaning Method Micrograms (ug) Carbon on the Surface Before After Cleanins Cleaning (a) petroleum this invention 819 18 0 (b) petroleum no HFC/HCFC 819 2221 blend rinse (c) petroleum no ketone cleaning 819 70 (d) synthetic this invention 508 29 (e) svnthetic no HFC/HCFC 508 2272 blend rinse (f) synthetic no ketone cleaning 508 499 (g) mineral oil this invention 950 15 (h) synthetic this invention 1033 25 In the e.,~J.,.i",~,"t~ with petroleum oil and synthetic oil, using an organic cleaning step followed by a fluu~u~ ,al blend of HCFC
and HFC vapor rinse step resulted in virtually complete cleaning of t~e coupon surface (>99.8% removal of carbon). However, in 30 u~yv~i~n-nLa (b) and (e), ;.i~,-ifica"l amount of carbon remained on th~ surface when the coupon was cleaned by a 30 second ;....r..aion in the ketone cleanin3 solvent only followed by a 30 second dryin~ in air without the HCFCIHFC vapor rinse. In ..,~.~,.i,.l~.,b (c), (f), (h) and a,, more carbon residue remained on the 35 surface when the coupon was cleaned by a 30 second il~ l.,.aiOI~ in HCFC-141b/HFC-365 ~ u~,~ followed by a 30 second drying in air than in the dual solvent process of this invention using the WO g4/28196 PCT/US94/06004 ~163351 terpene solvant cleaning step. This example de~lllOI l ~la~s that even when a strong fluo(~ul,t:",i~,al rinse solvent such as a b!end ~o"~:., ,g HFCF-141b is used, the combined organic Iketone) cleaning step followed by a fluolu~ lllical rinse step produces s greater cleaning than if a ketone solvent alone or a fluu~clcll~llli~dl solvent alone is used to clean the substrate.
FY~ nDle Eleven Soiled coupons were immersed in a 50/50 volume % mixture of liquid ~,tclol.a,~al~o~1~. â cyclic ketone, and HFC-365/FC-72 195:5 by weightl for 30 seconds at 56-59C followed by a 30 second ,iùn in a non ~ blend of 5% FC-72, a perfluu,oca,Lvn, and 95% HFC-365, a hydrofluu,u~.a,L~n, at ambient temperature and a 30 second vapor rinse with the co~,~u~ a~ LIu~, vapors of FC-72/HFC-365. the following results were noted:

WO 94/28196 ~1~ 3 ~ 5 1 PCTIU594106004 Expt. Oil on Substrate Cleaning Method ~1~ uy,c..":. (ug) Carbon on the Surface - 5 Before After Cleaning Cleaning (a) petroleum this invention 819 22 10 (b) petroleum no k~tone cleaning 819 44.3 (c) synthetic this invention 508 20.1 (d) synthetic no ketone cl~aning 508 453 (e) mineral oil this invention 950 21.3 (f) mineral oil no ketone cleaning 950 550 20 (~q) synthetic this invention 1033 20.4 (h) synthetic no ketone cleaning 1033 426 In the above ~.A~C.i..~ , using an orga liC cleanin~ step followed 25 by a flU~u~ .ll;Cdl vapor rinse step resulted in complete cleaning of the coupon surfac~ ~99.9% removal of carbon). More carbon r~sidu~ remained on the surface when the coupon was cleaned by a 30 second il",.,~. ,;ùn in the mixture of FC-72/HFC-365 followed by a 30 second dryin~ in air without usin~ the ~ lùh~a~lull~ solvent 30 cleanin~ step. This example d~ll.ù~ t~,~ that a fluc,lu.,ll_.,,;.,al vapor rinse step is required to ~ 'y clean a soiled surface which has been immersed in a ketone solvent, and neither the ketone solvent alone nor the fluc,lu,;ll .I;~.dl solvent alone is suffi-cient to ~ r clean the surface. In addition, it is well known 35 that perfluulu~,albùns such as FC-72 are very poor solvents for oils, but when blended with ~l~d~cl '( ùc_.Lùns or even Wo 94/28196 PCT/US94/06004 ~1633~1 I~J~u~ orluorucd,uons in the vapor or i"""~, aiùl~ rinse step of this process eombined with an organic eleaning step, the dual solvent process produces c~,,,,~JIvtvly clean coupons which could not be ..
co,,,~,lutuly cleaned by the individual solvent II,_."_uh,es.
..
FY ~nDle Twelve Soiled coupons were immersed in liquid c~cl~htl~allùl, a cyelic aleohol, which was not admixed with the HFC prior to cleaning (as in the previous ~ "Jle~). The eoupons were immersed for 30 seeonds at 56-59C followed by a 30 seeond ill~ _.aiùl~ in HFC-365, a hydroflv~oca,L~n, at ambient temperature and a 30 seeond vapor rinse with the vul~dvrlai,l~ a~e~b~ vapors of HFC-365. The followin~q results were noted:

Expt~ Oil on Substrate Cleaning Method r1i vg,a",a (ug) Carbon on the Surfaee Before After Cleaning Cleaning (a) petroleum this invention 819 18.5 (b) synthebe this invention 508 166 (e) mineral oil this invention 950 20.9 (d) synthetie this invention 033 22.4 In this e,~ .i",_.,l, the eleaning ability of the or~qanie eleaner ~ ar~lt~ d from the HFC was ~ vt~.~. The results are within 35 I;A,l,~.~.illlV. Ilal error to those of r-xample 4, where the admixed -sa-.

WO 94/28196 ~16 3 3 51 PCT/IJS94106004 organic/solvent system was evaluated. I"L~ L;"yl~, in this example the HFC/organic mixture in the cleaning sump cleaned better than if the cleaning sump contained only organic solvent (~.~CIOlleAclllol).
FY ~mDIe Thirteen Soiled coupons were immersed in liquid C~ ùlll~Aano~el a cyclic ketone, which was not admixed with the HFC prior to cleaning (as in the previous eA.",. q~. The coupons were immersed for 30 seconds at 56-59C followed bV a 30 second in""_(~;o,) in HFC-365, a hydrofl~o,ùc.-,Lu,,, at ambient temperature and a 30 second vapor rinse with the cond~ ;"~ aL~ up;~ vapors of HFC-365. The followirlg results were noted:

Expt. Oii on Substrate Cleanin~ Method ~' u~lal"s (u~) Carbon on the Surface 2 0 Before After Cleaning Cleaning (a) petroleum this invention 819 11.3 25(b) synthetic this invention 508 12.2 (c) mineral oil this invention 950 11.7 (d) synthetic this invention 1033 10.3 In this ~A,U_.i~ , the cleaning ability of the organic clr~aner 5~ .t~ d from the HFC was d, ."~f,~ ' The results are within C~A~JCli~ l error to those of Example 12, where the admixed 35 organic/solvent system was u;. ' ' 21~33~
It will be readiiy seen by one of ordinary skill in the art that the present invention fulfills all of the objects set forth above. After reading the foregoing -ueciric~lion~ one of ordinary skili will be able to effect various changes, substitutions of equivalents and various other aspects of the invention as broadly disclosed herein. It is therefore intended that the ,ulul~liol~ granted hereon be limited only by the definition contained in the appanded claims and equivalents thereof.

Claims (8)

1. A non-aqueous cleaning process for removing residual soils or surface contamination from a part, comprising the steps of:
(a) introducing the part into a cleaning compartment containing an organic or hydrocarbon cleaning fluid of sufficient solvency to substantially remove the contamination from said part;
(b) removing said part from said organic or hydrocarbon cleaning fluid and rinsing said part in a first rinsing compartment with a liquid rinsing agent of sufficient solvency for said soils or surface contamination but with at least sufficient solubility for said organic or hydrocarbon cleaning fluid to remove said organic or hydrocarbon cleaning fluid from said part, said rinsing agent consisting essentially of one or more hydrofluorocarbon compounds containing from about 3 to about 8 carbon atoms with at least 60% by weight of fluorine in the compounds, said compounds having linear or branched chains with a boiling point of from about 25°C to about 125°C; and (c) forming a flammability suppression blanket over the cleaning and first rinsing compartments during steps (a) and (b), said flammability suppression blanket consisting essentially of a substantially pure hydroflurocarbon vapor; and then (d) drying said part.

2. The process of claim 1, wherein said hydrofluorocarbons are selected from the following groups:
(1) compounds with the empirical formula:
C3HnF8-n where 1 n 4 (2) linear or branched compounds of the empirical formula: C4HnF10-n where 1 n 5 (3) linear or branched compounds of the empirical formula:
C5HnF12-n where 1 n 6 (4) linear or branched compounds of the empirical formula:
C6HnF14-n where 1 n 7 (5) linear or branched compounds of the empirical formula:
C7HnF16-n where 1 n 8 (6) linear or branched compounds of the empirical formula:
C8HnF18-n where 1 n 9

3. The process of claim 1 wherein the cleaning compartment contains an organic or hydrocarbon cleaning solvent mixed with a hydrofluorocarbon solvent which resulting mixture substantially removes contamination from said part and wherein the mixture is heated to a sufficient temperature to boil off at least some of the hydrofluorocarbon having a boiling point less than the hydrocarbon fluid so that the resulting vapor zone overlying the cleaning fluid is essentially a fluorocarbon based flammability suppression vapor zone.

4. The process of claim 3, wherein said hydrofluorocarbons are selected from the following groups:
(1 ) compounds with the empirical formula:
C3HnF8-n where 1 n 4 (2) linear or branched compounds of the empirical formula:
C4HnF10-n where 1 n 5 (3) linear or branched compounds of the empirical formula:
C5HnF12-n where 1 n 6 (4) linear or branched compounds of the empirical formula:
C6HnF14-n where 1 n 7 (5) linear or branched compounds of the empirical formula:
C7HnF16-n where 1 n 8 (6) linear or branched compounds of the empirical formula:
C8HnF18-n where 1 n 9

5. The process of claim 1, wherein said hydroflurocarbon rinsing agent and said organic or hydrocarbon cleaning fluid are selected so that any organic or hydrocarbon cleaning fluid present in the rinsing compartment containing the hydroflurocarbon rinsing agent separates at a predetermined low concentration from the hydrofluorocarbon and floats to the top of the rinsing compartment to provide a cascading effect of hydrocarbon cleaning fluid back into the cleaning compartment.

6. The process of claim 5, comprising the step of providing a second rinsing compartment containing substantially entirely only a hydroflurocarbon and providing a cascading effect of substantially pure hydrofluorocarbon rinse solvent into the first rinsing compartment to maintain a predetermined level thereof and to directionally provide a flow skimming action to sweep the separated hydrocarbon cleaning fluid back toward the cleaning compartment.

7. The process of claim 1, comprising the further step of housing the hydrocarbon cleaning compartment in a structure which is separate from a structure containing the rinsing compartment.

8. A non-aqueous cleaning process for removing residual soils or surface contamination from a part, comprising the steps of:

(a) introducing the part into an organic or hydrocarbon cleaning fluid of sufficient solvency to substantially remove the contamination from said part;
(b) removing said part from said organic or hydrocarbon cleaning fluid and rinsing said part by exposure in a liquid hydrofluorocarbon based rinsing solvent contained in a rinsing compartment separate from the cleaning compartment containing the organic or hydrocarbon cleaning fluid, said liquid hydrofluorocarbon based rinsing solvent being provided to remove said organic orhydrocarbon cleaning fluid from said part; and (c) forming a flammability suppression blanket over the cleaning and rinsing compartments during steps (a) and (b), said flammability suppression blanket consisting essentially of a substantially pure hydrofluorocarbon vapor; and then (d) drying said part.