Method for cleaning and drying of metallic and nonmetallic surfaces

The present invention relates to an aqueous composition and improved process useful for cleaning and facilitate drying of various metallic and non-metallic surfaces or components. According to the invention the water-immiscible hydrocarbon or non-halogenated organic solvent cleaning step is followed by an aqueous displacement solution (ADS) which contains a surfactant component and a pH modifier component in sufficient amounts to substantially displace the hydrophobic organic solvent residue from on the surface of the substrate and prevent its redeposition. The improved process is an alternative for replacing the ozone depleting chlorofluorocarbons and Halogenated solvents (ODS) or other volatile organic solvents (VOC) being commonly used in cleaning variety of industrially manufactured metallic and non-metallic components. The present invention provides an effective method for removal of various light and heavy surface contaminants such as, but not limited to, fluxes, oils, waxes, buffing and lapping compounds, finger prints, silicone oils, metal forming lubricants, polymers and mold release compounds.

FIELD OF THE INVENTION 
The present invention relates to an aqueous composition and improved 
process useful for cleaning and drying of various metallic and 
non-metallic surfaces or components. The improved process provides an 
alternative to replace the ozone-depleting chlorofluorocarbons, 
halogenated solvents and other volatile organic solvents (VOC) commonly 
used. The present invention provides an effective method for removal of 
various light and heavy surface contaminants such as fluxes, oils, waxes, 
buffing and lapping compounds, finger prints, silicone oils, metal forming 
lubricants, polymers and mold release compounds. 
BACKGROUND OF THE INVENTION 
Petroleum or synthetic hydrocarbons solvents as well as natural terpene 
hydrocarbon solvents or mixtures thereof, with or without other modifier 
additives, were recently reconsidered and commercialized as long-term 
alternative cleaning agents for the widely used, but gradually being 
phased out, chlorofluorocarbons (CFCs) (example 
1,1,2-trichloro-1,2,2-trifluoroethane) and other halogenated solvents such 
as dichloromethane, carbon tetrachloride, 1,1,1-trichloroethane, 
1,1,2-trichloroethylene and perchloroethylene. These solvents are used in 
cleaning fluxes from printed circuit boards (PCBs) and cleaning of various 
machine oils used in the manufacture of different metallic and 
non-metallic components (degreasing/vapor degreasing processes) as well as 
for cleaning other contaminants such as particulates, buffing, polishing, 
lapping compounds, waxes, paints. The CFCs and the halogenated solvents 
are known to deplete the stratospheric ozone layer. 
Ozone depletion leads to increasing the infiltrated ultraviolet radiation, 
which in turn increases potential incidents of cataracts, skin cancers and 
other human and ecological problems. The global consensus on an 
accelerated phaseout of materials with ozone depleting potential (ODP) is 
mounting. It has culminated recently in the "Montreal Protocol on 
Substances that Deplete the Ozone Layer" and in the revisions to 
accelerate the time limit for ending their production. 
The cleaning process using CFCs (or their azeotropic mixtures with protic 
solvents) or chlorinated solvents involves immersing the components to be 
cleaned in the solvent which is heated and ultrasonically cavitated for 
certain period of time. Then, the components are exposed to solvent vapor 
for secondary cleaning and rinsing. Following this step, the components 
are removed and left to air dry. The CFCs and some chlorinated solvents 
have two main advantages in this process because they are non-flammable 
and volatile at ambient or low temperature. Thus, drying of the components 
is not problematic. Also, some CFCs were commonly used to dry some 
aqueously cleaned surfaces through surface water-film displacement in a 
drying machine known as the CFC dryer. 
In contrast to CFCs, and halogenated solvents, water immiscible petroleum, 
synthetic and/or natural terpene hydrocarbons or hydrocarbons modified 
with other additives or surfactants are increasingly used as alternative 
sources for the cleaning of metallic and non-metallic surfaces. However, 
these solvents are always accompanied with rinsing and drying problems. 
Briefly, the cleaned surfaces are difficult to rinse and to dry and 
consequently, require prolonged drying times and relatively high 
temperatures. Drying of these solvents at high temperatures is associated 
with potential fire or environmental hazards, particularly those with low 
flash point solvents. Similar problems have also been found for surfaces 
cleaned with other water immiscible non-halogenated solvent cleaners 
including medium-high molecular weight alcohols, ethers, amines, esters 
and derivatives or mixtures. 
The above identified problems are attributed to the inherent properties of 
these hydrophobic solvents and circumstances related to their uses. For 
example, rinsing or displacement of surfaces cleaned with these solvents 
is difficult because of their inherent lower surface tension. Furthermore, 
these non-halogenated solvents tend to leave a very thin organic film, 
after cleaning and drying, absorbed on the surfaces which negatively 
interferes in many cases with the next step in a multi-step surface 
preparation such as coating, etching or vacuum coating deposition. Also, 
in some instances the cleaning solution contains surfactants which tend to 
undesirably emulsify the hydrocarbon solvent on rinsing with water in 
order to remove it, rendering phase separation of the solvent unfeasible 
for subsequent collection and recycling. 
It has been shown that several water rinse steps using plural rinses, 
following a cleaning step with either water-immiscible or 
water-emulsifiable or dispersable non-halogenated solvent cleaners at 
different temperatures, failed to completely remove the undesirable 
residue of the organic solvents in the relatively short time which is 
demanded by typical production requirements. The incomplete removal of the 
water-immiscible non-halogenated solvent film therefore renders many 
metallic and non-metallic surfaces, undesirably, water repellant or 
hydrophobic. 
Complete removal of the non-halogenated or hydrocarbon base solvent 
residues is essential, particularly in cleaning and drying of metals and 
non-metals with different configurations that are manufactured to be used 
in the electronic industry. Also, subsequent processes such as etching, 
plating, coating, vacuum vapor deposition or painting require water 
break-free or hydrophilic surfaces to produce good results. Otherwise, the 
surface may suffer differential etching or coat adhesion problems 
respectively. Furthermore, a partially hydrophobic surface tends to repel 
the rinse water leaving water droplets on the surface which may dry in 
place leaving residual marks on drying. Moreover, the residual un-rinsed 
non-halogenated solvent may contain some of the original surface 
contaminants. On the other hand, a water break-free surface drains the 
rinse water faster and requires less energy and time to dry. 
Metallic and non-metallic substrates which were first cleaned with a water 
immiscible (or partially water emulsifiable), heated, hydrocarbon base or 
non-halogenated solvent concentrate, by immersion in ultrasonically 
cavitated bath or which were submerged sprayed or simply dipped in with 
vertical or horizontal oscillation or rotation followed by rinsing with 
water, or a water diluted emulsion of the same hydrocarbon or 
non-halogenated solvent, ultrasonically cavitated, or sprayed or submerged 
sprayed followed by multi water rinses, failed to produce surfaces which 
are entirely free from the hydrophobic solvent residues. These residues 
may leave an undesirable residual odor of the natural or non-halogenated 
or petroleum hydrocarbon solvent or included additives; or interfere with 
the next step in a manufacturing operation process as mentioned above. 
Furthermore, the residual hydrocarbon or non-halogenated solvent with low 
flash point may create a fire-hazard if enough accumulates in the drying 
step which commonly uses recycled heated air. Air or inert gas drying 
techniques of those solvents require expensive and complex safeguards 
against fire hazard and to minimize their vapor release to the 
environment. 
It is therefore highly desirable to have an improved process and aqueous 
composition for the cleaning and drying of metallic and non-metallic 
surfaces which overcomes the above-noted drawbacks resulting from the 
incomplete removal of the hydrocarbon or non-halogenated solvent. The 
present invention diminishes the potential for a fire-hazard or an 
explosion, as well as reduces the drying time by effectively removing the 
non-halogenated organic solvent residues or other flammable 
water-immiscible cleaning solvents. Furthermore, the invention diminishes 
the drag-out or carry over of these solvents on parts, therefore, allows 
efficient and economic rinse-water recovery through closed loop 
purification systems. Typical purification systems include activated 
carbon to remove organic residues. The carbon has certain loading capacity 
for organics before exchange or disposal. 
Prior art related to the process and composition for the cleaning and 
drying of various surfaces has been disclosed in several patents. U.S. 
Pat. No. 5,041,235 describes a cleaning composition to clean porous 
surfaces containing a low molecular weight alcohol, synthetic hydrocarbon 
oil and a surfactant. U.S. Pat. No. 5,031,648 describes a spray method to 
clean mill gears soiled with gear lubes, greases and hardened residues 
with a composition containing a terpene hydrocarbon, aliphatic hydrocarbon 
solvent, surfactants, extreme pressure additive, thickeners and co-solvent 
followed by rinsing with a water-emulsifier soap solution in a pressure 
washer. U.S. Pat. No. 5,011,620 describes a cleaning composition of 
dibasic ester solvent and hydrocarbon solvent for cleaning flux residue 
from a printed circuit board. U.S. Pat. No. 4,983,224 describes a cleaning 
composition of terpenes/terpenols and polar aprotic solvents and a 
surfactant for cleaning fluxes. U.S. Pat. No. 4,877,556 discloses a 
cleaning composition of ethoxylated fatty alcohol, fatty acid ester, a 
monohydric alcohol, and liquid hydrocarbon for pretreatment of soiled 
fabrics before washing. U.S. Pat. No. 4,859,359 describes a composition 
which imparts water repellency to hard surfaces. The disclosed composition 
comprises a solvent mixture of glycol ether, a lower aliphatic alcohol, a 
hydrocarbon solvent and organic polysiloxane. U.S. Pat. No. 4,704,225 and 
Re. No. 33,210 describe a cleaning composition of terpene hydrocarbon, and 
a coconut oil fatty acid alkanolamide (an emulsifier) having water 
dispersed therein, water-in-oil emulsion. 
There is no disclosure in the above-noted patents which would tend to 
suggest or otherwise provide motivation for employing a water-immiscible 
solvent cleaner followed by a solvent displacement/cleaning step, before 
the water rinsing step, which utilizes a biodegradable and environmentally 
benign, aqueous composition capable of producing hydrophilic surfaces and 
also phase separates the water-immiscible solvent for recovery or 
recycling, and expedites the drying of the cleaned parts. 
SUMMARY OF THE INVENTION 
It has been found that the above objectives are accomplished by a process 
and an aqueous displacement solution composition according to the 
invention in which, the water-immiscible non-halogenated or hydrocarbon 
solvent cleaning step is followed by an aqueous displacement solution 
(ADS) which contains a surfactant component and a pH modifier component in 
sufficient amounts to substantially displace the hydrophobic hydrocarbon 
or non-halogenated organic solvent residue from the surface of the 
substrate and prevent its redeposition. The displacement of the 
hydrophobic hydrocarbon or non-halogenated organic solvent residue was 
found to be greatly enhanced by cavitating the ADS with an ultrasonic 
energy. The removed hydrocarbon or non-halogenated organic solvent residue 
coalesce to form an upper phase which can be overflown into a separator 
from which the hydrocarbon is removed and recycled. The aqueous solution 
phase is recycled to the original aqueous displacement solution bath. 
This hydrocarbon, or organic solvent, aqueous displacement step is followed 
by one or more water rinse steps, using air spray or submerged spray, 
oscillation, rotation, with or without ultrasonic energy cavitations where 
the aqueous displacement film is freely removed. A drying step follows in 
which the water film residues wetting the cleaned substrates are dried 
using heated air or other drying technique. 
The process of this invention may be used in cleaning of various metallic 
components such as metals and their alloys including, but not limited to, 
steel, aluminum, copper, titanium, beryllium, silver, gold, nickel, and 
non-metallic substrates including, but not limited to, glass, silicones 
and ceramics. Some examples of contaminants successfully and completely 
removed are Rigidax (high melting point wax component and additives) from 
a metal surface; a filling compound made of rubber gel in mineral oil base 
modified with olefin polymer from communication cable wires; heavy 
machining slurry composed of silicon and silicon carbide in a viscous 
cutting mineral oil from silicon wafers; various machining, tapping and 
stamping oils; silicon oils; highly viscous sulfurized heat treat oils 
used for hardening metals and lapping compounds mixed with oils. 
DESCRIPTION OF THE INVENTION 
It is an objective of the invention to provide an improved process and 
aqueous displacement solution (ADS) for the cleaning and drying of 
metallic and non- metallic surfaces which overcomes the above-noted 
drawbacks resulting from the incomplete removal of the hydrocarbon or 
non-halogenated solvent or other water-immiscible non-halogenated organic 
cleaning solvents. It is another objective to diminish the potential 
fire-hazard or an explosion while reducing the drying time by effectively 
removing the non-halogenated organic solvent residues or other 
water-immiscible cleaning solvents. It is a further objective to minimize 
the drag-out or the carry-over of the hydrocarbon or non-halogenated 
solvent into the rinses which increases the efficiency and the lifetime of 
the rinse water closed loop purification systems, thus minimizing waste 
and preserving water. 
The sequence of the cleaning operational steps in relation to this 
invention is as follows. Each step comprises one or plural steps. Each 
step may comprise immersion in ultrasonic bath or mechanical agitation or 
air spray or submerged spray and heat: 
1. Solvent cleaning step using a pure hydrocarbon or hydrocarbon base 
product or other water immiscible non-halogenated solvent, which 
solublizes and dislodges the contaminants on the surface, using sufficient 
heat and residence time. Agitation, oscillation or rotation or pressurized 
spray or submerged spray or ultrasonics or combination thereof is used. 
2. Solvent displacement with an ADS using agitation, oscillation or 
rotation or pressurized spray or submerged spray or ultrasonics or 
combination plus sufficient heat and residence time. 
3. Rinse with deionized water using agitation, oscillation or rotation or 
pressurized spray or spray under immersion or ultrasonics or combination 
plus sufficient heat and residence time. Other types of water may be used 
such as distilled, softened water, recycled water purified through a 
system includes activated carbon beds and ion exchange resin beds or 
through a membrane by reverse osmosis or ultra filtration or simply tap 
water. 
4. Drying. For expediency and handling of production rates, the preferred 
non-solvent drying technique of choice uses recirculated forced ambient or 
heated air with or without filtration. Other common drying methods may 
utilize infra-red heating, centrifuging, and vacuum drying or simply 
ambient forced air dry or combination thereof. Flat non-metal parts with 
no blind holes can be dried by immersion in heated water followed by slow 
vertical ascent withdrawal. 
In each of the first three steps one or more means is used to agitate the 
solution and/or to scrub the surface such as ultrasonic cavitations, 
pressurized spray or preferably spray under the cleaner surface or ADS 
surface or the rinse water surface. In step one, subsurface spray is 
preferred over pressurized air spray to minimize mist formation and the 
associated potential for fire or environmental hazard. The substrates may 
be kept in continuous motion utilizing tumbling, vertical or horizontal 
oscillation or rotation. Drying temperatures are sometimes dictated by the 
nature of the substrate. 
The cleaning process comprises displacing the hydrocarbon or the 
non-halogenated solvent residues on the surface with an acidic or neutral 
or alkaline aqueous solution comprising at least one surfactant added in 
sufficient amount in a separate step in the process before the water 
rinsing. The surfactant(s) preferably has low emulsification power for the 
hydrocarbon solvent or other non-halogenated water immiscible organic 
solvents. 
The aqueous displacing solution for use in accordance with this invention 
is preferably formulated so as to displace the water immiscible 
hydrocarbon solvent or the non-halogenated organic film on the metallic or 
non-metallic substrate with a water rinsable film, so that the substrate 
may subsequently freely rinsed with water and dried off in a shorter time. 
The general formula for the ADS according to the present invention, 
expressed as percent by weight, comprises one or more surfactants in an 
amount of about 0.01 to about 50 percent by weight, preferably, 0.01-10%, 
more preferably 0.01 to 1%; and/or an ionic surfactant in an amount of 
about 0.01 to about 50 percent by weight of said composition, preferably 
0.01 to 10%, more preferably 0.01 to 1%; and a pH modifier in an amount of 
about 0.00001 to about 10 percent by weight of said composition. However, 
it is understood that the general formula can be varied as expressed as 
percent by weight based on the purpose of usage. 
Preferred surfactants for use in accordance with the present invention are 
nonionic surfactants and anionic surfactants with low emulsification power 
for hydrocarbons or other water immiscible non-halogenated solvents. 
Particularly preferred nonionic surfactants include alkyl, alkylaryl or 
aryl glucosides and their alkyloxylated glucoside derivatives and 
alkyloxylated fatty alcohols or ethers. The aqueous displacing component 
formulations may comprise other optional anionic, nonionic surfactants or 
other additives. 
Examples are fatty esters, amines, diesters, amides, ethers and derivatives 
thereof with or without alkyloxylation and with or without termination. 
Particularly preferred anionic surfactants include alkyl or alkylaryl or 
aryl (with or without alkyloxylation) sulfates and sulfonates and 
phosphate esters and fatty acid salts. Other anionic components 
surfactants such as phosphonate acid or esters and fatty acids, diacids 
and polyacids and salts and derivatives with or without alkyloxylation may 
be used as optional ingredients to modify the ADS of the invention. 
Preferred anions for use to modify the pH in accordance with the present 
invention include hydroxides, carbonate, bicarbonate and phosphates of 
metals in group I & II elements. Other preferred pH modifiers include 
ammonia and ammonium salts or water soluble primary, secondary or tertiary 
amines with or without alkyloxylation and with or without termination. 
The preferred solvent aqueous displacing solution (ADS) in this invention 
comprises at least one anionic or one nonionic surfactant and at least one 
pH modifier and composed in sufficient amounts. 
The pH modifier is intended for the purpose of enhancing the hydrophobe 
displacement and its phase separation. In addition, the pH modifier is 
important to bring the pH to the desired level so that no harm such as 
undesired surface etch is done to the substrate. Preferred acids for use 
to modify the pH in accordance with the present invention include mineral 
acids and organic acids or polyacids with low molecular weight. More 
preferred acids or their partially neutralized or ammonium salts include 
sulfuric acid, nitric acid, phosphoric acid, hydrofluoric acid, formic 
acid, acetic acid, gluconic acid, glycolic acid, oxalic acid, tartaric 
acid and citric acid. 
One clear advantage of the present invention is the shortening of the 
drying time. For example, the drying time of a non-halogenated hydrocarbon 
solvent with relatively low vapor pressure can be reduced from 3 hours to 
30 minutes when ADS is used as compared to deionized water (See EXAMPLE 
6). The typical drying time under the temperatures ranging from 
180.degree. to 225.degree. F. is between 1 to 10 minutes depending on 
several variables. 
The substrate surface is tested for the water immiscible solvent removal by 
examining the surface for complete wettability or for water-break free 
surface by immersing the substrate, after the final water rinse, in an 
ambient deionized water followed by pulling it up slowly and observing any 
fast dewetting or shrinking spot(s). The degree of wettability is then 
determined versus the total surface area of the substrate. The degree of 
wettability according to the present invention is equal to the percentage 
of the surface divided by the total surface area.

The present invention will be better understood from the examples which 
follow, all of which are intended to be illustrative only and not meant to 
unduly limit the scope of the invention. 
EXAMPLE 1 
Table 1 summarizes the results obtained from cleaning various substrates 
(metallic and non-metallic) with different cleaning compositions according 
to this invention. Substrates were used after contaminating the surface 
with a thin film of about 2 mg/cm2 surface area of a mineral based 
machining oil. The oil (Amocut Tripur Cutting oil from Amoco, Chicago, 
Ill.) was spread evenly on the whole surface of the substrate. 
Substrates: 
1. Stainless steel (316-L) 2".times.4" panels 
2. Aluminum (6061) 2".times.4" panels 
3. Glass plates 4".times.4" 
4. Thin Ceramic plates 2".times.4" (used for manufacturing electronic 
circuit boards) 
5. Thin Silicone wafers 4".times.4" (parts for manufacturing solar energy 
panels) 
TABLE 1 
______________________________________ 
% 
Wettability 
Substrate Solvent /Wash with % with 
Wettability 
Cleaner ADS /Time agitation 
U/S 
______________________________________ 
I. Stainless 1 A 60 5 80 
Steel 1 A1 60 90 100 
2 B 60 15 100 
3 C 60 70 100 
4 D 30 85 100 
5 E 30 70 100 
II. Aluminum 1 A 60 5 75 
1 A1 60 90 100 
2 B 45 25 95 
3 C 60 95 100 
4 D 30 30 100 
5 E 30 50 100 
III. Silicone 1 A 50 90 
Wafers 1 A1 85 100 
2 B 45 90 100 
3 C 60 85 100 
4 D 85 100 
5 E 45 75 100 
IV. Glass 1 A 70 100 
1 A1 85 100 
2 B 45 90 100 
3 C 60 25 100 
4 D 30 70 100 
5 E 50 75 
V. Ceramic 1 A 40 90 
1 A1 60 100 
2 B 45 95 100 
3 C 60 90 100 
4 D 90 100 
5 E 80 100 
______________________________________ 
1. Bioact .RTM. EC7R. An orange terpene hydrocarbon (Petroferm Inc., 
Fernandina Beach, FL). 
2. THO130. A hydrotreated light petroleum distillate (Sun Refining and 
Marketing Company, Philadelphia, PA). 
3. Axarel .RTM. 9100. A mixed aliphatic hydrocarbons and aliphatic esters 
(E. I. du Pont, Wilmington, DE). 
4. Exxate .RTM. 1000. Water immiscible C10 branchedchain synthetic ester 
(Exxon Chemical Americas, Houston, TX). 
5. Actrel .RTM. 4493L. Aliphatic petroleum hydrocarbon (Exxon Chemical 
Americas, Houston, TX). 
A: Nonylphenoxyethoxyethanol (1% by weight). 
A1: Nonylphenoxyethoxyethanol (1% by weight) and potassium hydroxide 
(0.005% by weight), pH is about 9-11. 
B: Chem Crest 165 (Crest Ultrasonics, Trenton, N.J.), a mixture of anioni 
surfactant, citric acid and ammonium citrate and formaldehyde condensate, 
pH is about 5-7. 
C: Chem Crest 211 (Crest Ultrasonics, Trenton, N.J.), a mixture of anioni 
and nonionic surfactants, triethanolamine and sodium metasilicate, pH is 
about 10-12. 
D: Composition : Ethal DA9, nonionic surfactant (Ethox Chemicals, 
Greensborough, N.C.); Triton CG110 a polyglucoside nonionic surfactant 
(Union Carbide, Danbury, CT) and sodium carbonate, pH is about 8-9. 
E: Chem Crest 55 from Crest ultrasonics, a mixture of nonionic surfactant 
glycol ether, amine salt and phosphoric acid, pH is about 1-5. 
EXAMPLE 2 
Table 2 below illustrates the removal of the solvent cleaner from on the 
substrates, prepared as described in example 1, when sprayed rinsed with 
water, at 120.degree. F. and when rinsed in sonicated overflowing water, 
at 120.degree. F., for 60 seconds. 
TABLE 2 
______________________________________ 
% Wettability 
% Wettability 
Substrate Solvent spray rinse 
sonicated rinse 
______________________________________ 
I. Stainless 5 5 25 
Steel 
II. Aluminum 1 5 70 
5 15 75 
III. Silicone 5 20 70 
IV. Glass 5 5 20 
______________________________________ 
EXAMPLE 3 
The following example (Table 3) illustrates the improvement in the removal 
of solvent residues using this invention. The solvent used in this example 
is Axarel.RTM. 9100 (E. I. dupont, Wilmington, Del.). This solvent cleaner 
is composed of mixed aliphatic hydrocarbons, aliphatic esters. The 
substrates were used after contaminating the surface with a thin film of 
about 2 mg/cm2 surface area of a mineral oil based machining oil. The oil 
was spread evenly on the whole surface of the substrate. The substrates 
were immersed in a circulated Axarel liquid concentrate heated at 
150.degree. F. for 1 minute, rinsed with water for 10 seconds, immersed in 
agitated solution of an aqueous cleaner composition according to this 
invention heated at 140.degree. F. for 45 seconds and then rinsed with 
water spray at 110.degree. F. for 45 seconds. 
TABLE 3 
______________________________________ 
% Wettability 
% Wettability 
Substrate ADS* with no sonics 
with sonics 
______________________________________ 
1. Stainless No 25 
Steel Yes 95 100 
2. Silicon No 25 
wafer Yes 95 100 
3. Silicone No 5 
Yes 95 100 
4. Glass No 70 
Yes 95 100 
5. Aluminum No 10 
Yes 70 100 
______________________________________ 
*The aqueous cleaner is composed of sodium naphthalene sulfonate, citric 
acid, ammonia and potassium hydroxide. pH of the aqueous cleaning solutio 
was about 6-8. 
Substrates: 
1. Stainess steel (316L) 2" .times. 4" panels; 
2. Thin Silicone wafers 4" .times. 4"; 
3. Glass plates 4" .times. 4"; 
4. Thin Ceramic plates 2" .times. 4"; 
5. Aluminum (6061) 2" .times. 4" panels. 
EXAMPLE 4 
The following industrially manufactured components were processed according 
to the invention. Each group of substrates were subjected to the process 
described below. In each case the substrates were examined for complete 
removal of the contaminants and for complete wettability. 
1. Brass pin eyelets. Contaminant is starine wax soldering flux. 
2. Cylindrical metal plated electronic capacitors of various sizes. 
Contaminants are machining mineral oil and welding RMA flux. 
The parts were placed in a suitable stainless steel flat or electrically 
driven rotating basket and processed as follows: 
(1). The parts were immersed in a 10".times.14".times.10" ultrasonic 
stainless steel tank (Manufacturer: Crest Ultrasonics, Trenton, N.J.) 
filled with Axarel.RTM. 32 solvent cleaner (E. I. du Pont, Wilmington, 
Del.), at 160.degree.-170.degree. F., for 5-10 minutes. This solvent 
cleaner is composed of mixed aliphatic hydrocarbons, aliphatic esters and 
nonionic surfactants. The ultrasonic bath transducers were powered by a 
Genesis SA generator at 90 watts/gallon and sweep frequency of 38-42 Khz. 
(2). The parts were allowed to drain the excess hydrocarbon solvent for 30 
seconds and then immersed in another similar 10".times.14".times.10" 
ultrasonic tank charged with Chem Crest 103, a mild alkaline solution 
(Crest Ultrasonics, Trenton, N.J.; pH=8-9.5, a mixture of 
nonylphenoxyethoxyethanol, coconut diethanolamide/diethanolamine and 
hexylene glycol), at 4% concentration and heated at 
140.degree.-150.degree. F. for 5 minutes. The ultrasonic transducers were 
powered by a Genesis generator at 90 watts/gallon and sweep frequency of 
39-41 Khz. 
(3). The parts were allowed to drain the aqueous cleaner for 30 seconds and 
then sprayed with deionized water then immersed in another similarly 
ultrasonically powered tank charged with overflowing deionized water at a 
rate of 1 gallon/minute and heated at 100.degree.-110.degree. F. for 2 
minutes. 
(4). The parts were allowed to drain for 30 seconds and then immersed in 
another similar ultrasonically powered overflowing tank charge with 
deionized water which was heated at 100.degree.-110.degree. F. for w 
minutes. The parts exit between deionized water spraying headers and were 
then allowed to drain for 30 seconds. 
(5). The parts were exposed to air blowoff knives for 15 seconds before 
immersion in a circulated hot air dryer heated at 190.degree.-210.degree. 
F. Sample of the parts were examined for wettability after step number 4 
by fully immersion in a deionized water and were found fully wettable. The 
parts were examined for unremoved flux under long wave ultraviolet light 
or visually under a stereo microscope at 10-45 magnification and were 
found free from any residues. It was noted that the Axarel 32 phase 
separated and on the surface of the aqueous displacement solution in step 
(2), where it was moved into a separation tank or a decanter. 
EXAMPLE 5 
The following industrially manufactured components were processed according 
to the invention. Each group of substrates were subjected to the process 
described below. In each case the substrates were examined for complete 
removal of the contaminants and for complete wettability. 
1. Ingot 10".times.4".times.5" of machined silicone wafers. Surface 
contaminants are SAE 30 mineral oil, silicone particles and silicone 
carbide. 
2. Titanium and steel impellers 7" and 10" diameter. Contaminant is thick 
green wax (Rigidax) compound. 
3. Stainless steel and brass pin points. Contaminant is heavy cutting 
mineral oil product. 
The parts were placed in a suitable stainless steel flat or electrically 
driven rotating basket and processed as follows: 
(1). The parts were immersed in a 10".times.14".times.10" stainless steel 
tank with two parallel spray headers installed close to the bottom of the 
tank and powered by a chemically resistant pump (Manufacturer: Crest 
Ultrasonics, Trenton, N.J.). The tank was filled with Axarel 9100 solvent 
cleaner (From E. I. du Pont, Wilmington, Del.) and heated at 
165.degree.-175.degree. F. The parts were then subjected to the submerged 
spray for 5-10 minutes. 
(2). The parts were allowed to drain the excess hydrocarbon solvent for 30 
seconds and then immersed in another similar 10".times.14".times.10" 
ultrasonic tank charged with Chem Crest 103, a mild alkaline cleaner or 
Chem Crest 211 alkaline cleaner (from Crest Ultrasonics, Trenton, N.J.), 
at 5% concentration and heated at 140.degree.-150.degree. F. for 5-10 
minutes. The ultrasonic transducers were powered by a Genesis generator at 
90 wats/gallon and sweep frequency of 39-41 Khz. 
(3). The parts were allowed to drain the aqueous cleaner for 30 seconds and 
then sprayed with deionized water than immersed in another similar 
ultrasonically powered tank charged with overflowing deionized water at a 
rate of 1 gallon/minute and heated at 100.degree.-110.degree. F. for 2 
minutes. 
(4). The parts were allowed to drain for 30 seconds and then immersed in 
another similar ultrasonically powered overflowing tank charged with 
deionized water which was heated at 100.degree.-110.degree. F. for 2 
minutes. The parts exit between deionized water spraying headers and were 
then allowed to drain for 30 seconds. 
(5). The parts were exposed to air blowoff knives for 15 seconds before 
immersion in a circulated hot air dryer heated at 190.degree.-210.degree. 
F. Sample of the parts were examined for wettability after step number 4 
by fully immersion in a deionized water and were found fully wettable. The 
parts were examined for unremoved oil contaminants under long wave 
ultraviolet light or visually under a stereo microscope at 10-45 X 
magnification or by the clean cloth wipe test were found free from any 
residues. It was noted that the Axarel 9100 phase separated on the surface 
of the aqueous cleaner in step 2, where it was removed into a separation 
tank or a decanter. Using a circulating pump connected to the tank where 
the return solution is pumped close to the solution at slow rate, the 
floating hydrocarbon solvent was sparged out to a decanter. The solution 
was allowed to phase separate and the aqueous cleaner solution was 
returned to tank 2. The hydrocarbon solvent is optionally returned to tank 
1 or collected and distilled under vacuum for reuse or collected for 
proper waste disposal. 
EXAMPLE 6 
The following industrially manufactured components were processed according 
to the invention. Each group of substrates were subjected to the process 
described below. In each case the substrates were examined for complete 
removal of the contaminants and for complete wettability. 
1. Chrome plated steel piston rings. Contaminants are mineral oil, lapping 
compound, silicone carbide. 
2. Semicircular flat galvanized steel wires of various diameters. 
Contaminant is a highly viscous sulfurized heat treat oil. 
The parts were placed in a suitable stainless steel fixture and processed 
as follows: 
(1). The parts were immersed in a 10".times.14".times.10" ultrasonic 
stainless steel tank (Manufacturer: Crest Ultrasonics, Trenton, N.J.). The 
ultrasonic bath transducers were powered by a Genesis.RTM. SA generator at 
90 watts/gallon and sweep frequency of 38-42 Khz (Manufacturer: Crest 
Ultrasonics, Trenton, N.J.). The tank is also fitted with a deeply seated 
spray headers connected to a chemically resistant circulating pump to 
spray the solvent under its surface. The rank was filled with Axarel.RTM. 
9100 solvent cleaner (From E. I. du Pont, Wilmington, Del.), at 
150.degree.-160.degree. F. The parts were first submerged sprayed for 3 
minutes and then turned off and the sonics were turned on for 2 minutes 
then the sequence was repeated one more time. 
(2). The parts were allowed to drain the excess hydrocarbon solvent for 30 
seconds and then immersed in another similar 10".times.14".times.10" 
ultrasonic tank charged with Chem Crest 211 (From Crest Ultrasonics, 
Trenton, N.J.), at 5% concentration and heated at 140.degree.-150.degree. 
F. for 5-10 minutes. The ultrasonic transducers were powered by a 
Genesis.RTM. generator at 90 watts/gallon and sweep frequency of 39-41 
Khz. 
(3). The parts were allowed to drain the aqueous cleaner for 30 seconds and 
then sprayed with deionized water than immersed in another similar 
ultrasonically powered tank charged with overflowing deionized water at a 
rate of 1 gallon/minute and heated at 100.degree.-110.degree. F. for 2 
minutes. 
(4). The parts were allowed to drain for 30 seconds and then immersed in 
another similar ultrasonically powered overflowing tank charged with 
deionized water which was heated at 100.degree.-110.degree. F. for 2 
minutes. The parts exit between deionized water spraying headers and were 
then allowed to drain for 30 seconds. 
(5). The parts were exposed to air knives for 15 seconds before immersion 
in a circulated hot air dryer heated at 190.degree.-210.degree. F. 
Sample of the parts were examined for wettability after step number 4 by 
fully immersion in a deionized water and were found fully wettable. The 
parts were examined for unremoved oils under long wave ultraviolet light 
or examined visually under the microscope at 10-45 X or by the clean wipe 
cloth test and were found free from any residues. It was noted that the 
Axarel.RTM. 9100 separated on the surface of the aqueous displacement 
solution step (2), where it was removed into a separation tank or a 
decanter. 
EXAMPLE 7 
This example illustrates the improvement in drying time according to this 
invention. Telecommunication exposed cable end wires filled with extended 
thermoplastic rubber gel modified with olefinic polymers were processed 
according to this invention as follows. 
A cable end was placed in a suitable stainless steel fixture and processed 
as follows. Material of construction limited the maximum temperature to 
135.degree. F. 
Process A 
1. The cable end wires were immersed in a 12".times.18".times.12" stainless 
steel tank (Manufacturer: Crest Ultrasonics, Trenton, N.J.). The tank is 
fitted with a deeply seated spray headers connected to a chemically 
resistant circulating pump to spray the solvent under its surface. The 
tank was filled with Axarel.RTM. 9100 solvent cleaner (From E.I. du Pont, 
Wilmington, Del.), at 150.degree.-160.degree. F. The parts were submerged 
sprayed for 10 minutes at 130.degree. F. with vertical oscillation. 
2. The cable end wires were allowed to drain the excess hydrocarbon solvent 
for 3 minutes and then immersed in another similar 12".times.18".times.12" 
ultrasonically activated tank charged with Chem Crest 211 (From Crest 
Ultrasonics, Trenton, N.J.), at 5% concentration heated at 135.degree. F. 
for 5 minutes. The ultrasonic transducers were powered by a Genesis 
generator at 90 watts/gallon and sweep frequency of 39-41 Khz. 
3. Step 2 was repeated in another similar tank under the same set of 
conditions. 
4. The cable end wires were allowed to drain the aqueous cleaner for 1 
minute and then sprayed with deionized water then immersed in another 
similar ultrasonically powered tank charged with overflowing deionized 
water at a rate of 1 gallon/minute and heated at 135.degree. F. for 3 
minutes 
5. The cable end wires were subjected to deionized water air spray for 2 
minutes and then allowed to drain for 30 seconds. 
6. The cable was immersed in a circulated hot air dryer heated at 
135.degree. F. for 30 minutes. 
Process B 
1. A cable end was immersed in a 12".times.18".times.12" stainless steel 
tank (Manufacturer: Crest Ultrasonics, Trenton, N.J.). The tank is fitted 
with a deeply seated spray headers connected to a chemically resistant 
circulating pump to spray the solvent under its surface. The tank was 
filled with Axarel.RTM. 9100 solvent cleaner (From: E.I. du Pont, 
Wilmington, Del.), at 150.degree.-160.degree. F. The parts were submerged 
sprayed for 10 minutes at 130.degree. F. with vertical oscillation. 
2. The cable was allowed to drain for 3 minutes and then immersed in a 
circulated air dryer heated at 135.degree. F. for 3 hours. 
Process C 
1. A cable end was immersed in a 12".times.18".times.12" stainless steel 
tank (Manufacturer: Crest Ultrasonics, Trenton, N.J.). The tank is fitted 
with a deeply seated spray headers connected to a chemically resistant 
circulating pump to spray the solvent under its surface. The tank was 
filled with Axarel.RTM. 9100 solvent cleaner (From: E.I. du Pont, 
Wilmington, Del.), at 150.degree.-160.degree. F. The parts were submerged 
sprayed for 10 minutes at 130.degree. F. with vertical oscillation. 
2. The cable was allowed to drain and air dry under the hood for 48 hours. 
Each processed cable end wires was examined visually and by wiping the 
wires with a clean cloth for dryness and residual gel. The wires of the 
cable end according to process A was completely clean and dry. Residual 
Axarel solvent was detected on both of the cable wires cleaned according 
to processes B and C.