WO1991019831A1

WO1991019831A1 - Cycloparaffins containing cleaning composition and method of using them

Info

Publication number: WO1991019831A1
Application number: PCT/US1991/003992
Authority: WO
Inventors: Maher Ebeid Tadros; Craig Allen Matzdorf; Tushar Kanaiyalal Shah
Original assignee: Martin Marietta Corporation
Priority date: 1990-06-11
Filing date: 1991-06-06
Publication date: 1991-12-26
Also published as: AU8103091A; CA2082071A1

Abstract

Compositions and methods are provided for removal of grease and other contaminants from surfaces by employing cleaning compositions containing cycloparaffins, branched paraffins, and surfactants. Blends containing cycloparaffins and branched paraffins, such as Conoco XP-15 and Conoco XP-20, may be used along with surfactants such as dinonylphenoxypoly (ethyleneoxy) ethanol, sodium lauryl sulfate, trimethyl hexadecyl ammonium chloride, and sodium dodecylbenzene sulfonate.

Description

CYCLOPARAFFINS CONTAINING CLEANING COMPOSITION AND METHOD OF USING THEM

Field of the Invention

The present invention relates to compositions for general-purpose degreasing as well as precision cleaning. The compositions are water rinseable and possess favorable characteristics such as low toxicity, environmental acceptability, low odor, and extremely good cleaning ability.

Background of the Invention In the course of most manufacturing operations and industrial processes, tools and parts become contaminated with various greasy, waxy, oily substances that have to be removed for subsequent processing or for end application. For example, in metal working operations, the incoming materials will be contaminated with substances such as cosmolene and rust preventative oil and may then pick up preservative compounds such as Multifak EP-2 from die faces and Mil-C-16173 from tools and equipment. During forming, many lubricants may then be used, such as drop hammer lubricants (e.g. Houghton 431, castor oil, Houghton 3108), tube bending lubricants (e.g. Houghton 3105, Mil-H-5606, Titen Lube 1129) and miscellaneous other forming lubricants (e.g. Ci flo 20, petrolatum). Then during machining another series of contaminants appears as, for example, coolants (e.g., Tri sol), drilling aids (e.g. beeswax), cutting aids (e.g. WD-40), stamping lubricants (e.g. Johnsons wax) and grinding and honing oils and machine oil.

It is difficult if not impossible to operate without greases and oils for lubrication, corrosion protection etc., and their removal has always been a challenge in production, maintenance, repair, etc. Conventionally, these greases and oils have been removed using various solvents (principally organic) and water-based cleaners. While there are specific cleaners of this type available that will degrease effectively for a certain number of different contaminants, generally there are types of contamination resistant to each cleaner. Accordingly, it is not possible to use a single degreaser for all cleaning operations, and a degree of specialist knowledge is required to ensure that particular contaminants are removed. Also many cleaners are only effective with long treatment times and/or high temperatures for specific contaminants, thus complicating the procedures for clean-up of parts having a variety of contaminants. In addition, or certain contaminants such as cosmolene, there are virtually no satisfactory cleaners available.

Amongst the solvents used for degreasing are the chlorofluorocarbons, also known as CFC's or freons, such as CFC-113, that have been widely used with considerable success, primarily because of their non-fla mability and low toxicity. These chemicals are now under scrutiny because they have been linked with stratospheric ozone depletion and "greenhouse effects". Some chlorocarbons such as trichloroethylene (TCE) and 1,1,1 trichloroethane (TCA) are now being used for cleaning purposes, perhaps because of their reduced ozone depletion potential as compared to CFC's. However, these are hazardous materials and are associated with health and environmental problems. In addition, even though the chlorocarbons and the chlorofluorocarbons are non-flammable, they possess very high vapor pressure and so typically 50% or more of the liquid is lost to the atmosphere during use. Other traditional organic cleaners such as aliphatic ketones (e.g. methyl ethyl ketone (MEK) and acetone) and methylene chloride are similarly falling into disfavor due to toxicity and low flash point.

To address the health and environmental concerns, numerous aqueous cleaners have been developed and are commercially available, but none of these can rival the cleaning efficiency of the above referenced organics, particularly for the removal of heavy greases. Examples of the aqueous cleaners include glycol ethers, silicates and phosphates. Another class of cleaning agent that is being used increasingly in the electronics industry is the terpene group, including such compounds as pinene, gamma terpinene, limonene, and dipentene. These compounds have the ability to dissolve or complex with rosin solder fluxes, oils, waxes, and greasy substances, and are characterized by relatively low toxicity and environmental biodegradability. However, the terpenes have v&ry strong citrus odor and low flash point, both of which contribute adversely to human working conditions and safety. For example, two widely used commercial terpene formulations, Bioact DG-1 and Bioact DG-3 have a strong odor and a flash point around 115°F, whereas any material with a flash point lower than about 140°F is conventionally considered to be flammable.

Industrial trials have been conducted with a wide variety of water-based cleaners, freons and terpenes, comparing their effectiveness against the most significant metal working contaminants. In one such test by General Dynamics ("Evaluation of Water-Based, Terpene and Freon Degreasers," presented at the Waste Minimization Symposium, Los Angeles, California, 1988), a detailed comparison was made of five aqueous degreasers that had been selected as particularly effective: Grace Daraclean 282, Quaker 624 GD, Brulin 815 GD, Turco 42-15, and Oakite Okemclean. Typically, these were effective on some of the contaminants tested. However, none were able to remove cosmolene, even at 160^βF, the highest temperature tested. The freons tested were used in the vapor phase, and were effective against all contaminants except cosmolene, carbowax and mill marks. The terpenes rapidly cleaned most contaminants except carbowax and mill marks. However, extended immersion times were required to remove cosmolene.

Conventional soaps, detergents, and surfactants can also be applied to degreasing, but these are ineffective in cleaning heavy greases.

Petroleum distillates have been used as degreasing agents, particularly in automotive and heavy industrial applications. Typical ingredients include aliphatic petroleum distillates and lesser amounts of aromatic petroleum naphtha, both of which have been identified as possible carcinogens by the National Toxicology Program. In addition, these distillates have strong noxious odor, relatively low breathability limits (e.g., TLV (threshold level value)= 100 p.p.m. in air) and are combustible.

Cycloparaffins have conventionally been used as carrier fluids for pesticides, bases for adhesives, and as diluents in chemical synthesis reactions. However, there is no suggestion of using cycloparaffins in combination with branched paraffins and surfactants as water rinseable degreasing liquids.

Summary of the Invention

It is an object of the present invention to provide a new cleaning composition useful for applications ranging from heavy duty industrial removal of grime, grease and oil, to precision cleaning of delicate optics and electronic components.

Another object of the present invention is to provide a heavy duty degreasing composition which will not damage the original surface and will leave it in suitable condition for subsequent treatment and processing, e.g., application of adhesives or corrosion protective coatings.

Another object of the present invention is to provide a cleaning composition that is effective against a broad spectrum of contaminants including grease, oils, fats, cosmolene, waxes, silicones, bitumen, tars and grime.

A further object of the present invention is to provide a cleaning composition comprising a mixture of cyloparaffins, branched paraffins and surfactants for general cleaning and degreasing applications. The compositions are water rinseable and are characterized by favorable properties such as low toxicity, environmental acceptability, low odor, low flammability, high boiling point, high stability, and good cleaning efficacy for a broad range of contaminants. Another object of the present invention is to provide a method of cleaning a contaminated surface by contacting the surface with a cleaning composition comprising a mixture of cycloparaffins, branched paraffins and surfactants.

These and other objects of the present invention will be more clearly understood from the descriptions of preferred embodiments that follow.

Brief Description of the Drawings

Figure la is a Fourier Transform Infrared (FTIR) reflectance spectrum of an aluminum surface contaminated with DOW #704 silicon oil showing numerous contamination peaks.

Figure lb is an FTIR reflectance spectrum of the same aluminum surface as in Figure la after removal of the DOW #704 silicon oil using a cleaning composition of the present invention.

Figure 2a is an FTIR reflectance spectrum of an initially clean conversion coated aluminum surface.

Figure 2b is the FTIR reflectance spectrum of the same conversion coated aluminum surface as in Figure 2a after contaminating with DOW #704 silicon oil .

Figure 2c is the FTIR reflectance spectrum of the same conversion coated aluminum surface as in Figure 2b after removal of the DOW #704 silicon oil using a cleaning composition of the present invention.

Description of Preferred Embodiment

A water rinseable cleaning composition is provided which comprises a mixture of cycloparaffins, branched paraffins and surfactants. The cleaning composition may comprise from about 15 to about 90 weight percent cycloparaffin, from 0 to about 60 weight percent branched paraffin, and from about 0.1 to about 60 weight percent surfactant. Preferably, the cleaning composition comprises from about 25 to about 85 weight percent cycloparaffin, from about 5 to about 50 weight percent branched paraffin, and from about 1 to about 50 weight percent surfactant. More preferably, the cleaning composition comprises from about 30 to about 75 weight percent cycloparaffin, from about 8 to about 45 weight percent branched paraffin, and from about 10 to about 35 weight percent surfactant. Most preferably, the cleaning composition comprises from about 35 to about 70 weight percent cycloparaffin, from about 10 to about 40 weight percent branched paraffin and from about 15 to about 30 weight percent surfactant.

Suitable cycloparaffins for the present invention include cycloalkanes of the one ring type, e.g., cycloheptanes and cyclooctanes (general formula C_nH2_n) or dicyclic (general formula C_nH _n_2) or tricyclic (general formula _nH2_n_4) or may indeed contain larger multi-ring systems. Typical cycloparaffins may be branched, e.g., may contain methyl and/or ethyl branches attached to the cyclic ring(s). The cycloparaffins may contain from 6 to greater than 50 carbon atoms. Typically, the cycloparaffins contain from about 8 to about 30 carbon atoms. When isolated from petroleum the cycloparaffins contain rings with five, six, or seven carbon atoms and alkyl derivatives of cyclopentane and cyclohexane are commonly found. It is generally preferred to employ cycloparaffins with relatively high average molecular weight that have less odor, lower flash point, and lower toxicity. However, for specific applications, it may be desirable to utilize more highly refined, or specific cycloalkanes such as cyclohexane or cyclopentane, for example.

Branched paraffins are defined as paraffins which contain one or more segments of four carbons attached to each other nonlinearly as shown below:

I

CH₂ I Suitable branched paraffins contain from 4 to greater than 50 carbon atoms. Typically, the branched paraffins contain from about 8 to about 30 carbon atoms. The cycloparaffin and branched paraffin constituents of the present invention may be provided in the form of blended mixtures. Blends containing both cycloparaffins and branched paraffins may be obtained as distillate fractions from crude oil refining and from catalytic reformer effluent or may be prepared by controlled hydrogenation of corresponding unsaturated hydrocarbons. Various blends comprising both cycloparaffins and branched paraffins are commercially available. Examples of some suitable commercially available blends include Conoco XP-10 (100^βF) having a density of 0.79, Conoco XP-13 (130^βF) having a density of 0.80, Conoco XP-14 (140^*F) having a density of 0.81, Conoco XP-15 (150^βF) having a density of 0.81, and Conoco XP-20 (200^βF) having a density of 0.82, where the temperature designations in parentheses are the flash points. The increasing flash point corresponds to increasing average molecular weight and is accompanied by an increase in boiling point and reduced odor. Chemical analysis reveals that Conoco XP-10 is primarily made up of cycloparaffins and branched paraffins containing 9 to 11 carbon atoms, while Conoco XP-15 is primarily composed of cycloparaffins and branched paraffins containing from 11 to 13 carbon atoms. Conoco XP-20 primarily comprises cycloparaffins and branched paraffins containing 14 to 28 carbon atoms. Although these blends are mainly cycloparaffinic, they contain significant quantities of branched paraffins. Thus, for example, while Conoco XP-10 is known to be approximately 85 weight percent naphthenic (i.e., cyclic saturated hydrocarbons), Conoco XP-20 is only about 50 weight percent naphthenic and the balance in both cases is largely branched paraffin. More specifically, Conoco XP-20 is known to comprise about 55 weight percent cycloparaffin (43 weight percent branched cycloparaffin and 12 weight percent bicycloparaffin) and about 37 weight percent branched paraffin, with the remainder largely comprising linear paraffin; For room temperature cleaning, it has been found that compositions containing XP-10 tend to clean slightly faster than compositions containing XP-15 or XP-20. However, cleaning times decrease with increasing cleaning temperature and it is possible to clean at higher temperatures with compositions containing XP-15 and XP-20 while still remaining below their flash points. In general, cycloparaffin/branched paraffin blends are very complex mixtures of hydrocarbons typically characterized by high average molecular weight, high boiling point and low percentages of normal paraffins and aromatics. The cycloparaffins and branched paraffins of the present invention may also include lesser amounts of other hydrocarbons including aliphatic, branched aliphatic, and aromatic compounds, and terpenes and terpene rings. Preferably, the cycloparaffins and branched paraffins are used in such combinations so as to obtain a relatively high boiling point. For general purpose usage it has been found that mixtures of cycloparaffins and branched paraffins with a boiling point in the range of 300^βF - 600^βF are preferred and 350^βF - 550^*F are most preferred.

The cleaning compositions of the present invention also contain a surfactant, such as a soap or a detergent. The surfactant can be nonionic, amphoteric, cationic, or anionic. Mixtures of surfactants can be employed if desired.

Examples of some nonionic surfactants include the alkylene oxide condensation products with higher aliphatic alcohols, alkyl phenols, carboxylic acids, amides, amines, and sulphonamides. A preferred nonionic surfactant is dinonylphenoxypoly (ethyleneoxy) ethanol which is commercially available from Rhone-Poulenc, Inc. as Igepal DM-530.

Examples of some ionic surfactants include higher (C3-CJ3) fatty acid sulfonic acid or salts thereof, such as the sodium, potassium, and ammonium salts thereof. One particular sulfonic acid is the sodium salt of oleic acid sulfonate. Another ionic surfactant has the formula RNHR'COOH wherein R is an aliphatic group having from 8 to 18 carbon atoms and R' is an alkyl group having from 1 to 8 carbon atoms, and salts thereof. R is preferably a higher fatty group and R' preferably has from 1 to 4 carbon atoms. Suitable salts include sodium, potassium, and ammonium salts. A particular surfactant of this type is the sodium salt of N-coco betaamine propionate. Other examples of ionic surfactants are the alkyl benzene sulfonic acids and alkali metal or ammonium salts thereof. A preferred alkyl benzene sulfonic acid is linear alkyl benzene sulfonic acid having from 8 to 18 carbon atoms in the alkyl group, such as dodecylbenzene sulfonic acid. Sodium lauryl sulfate, trimethyl hexadecyl ammonium chloride, and sodium dodecylbenzene sulfonate are also suitable surfactants.

The surfactants is employed in amounts sufficient to achieve water rinseability, which amounts are usually at least about 0.1 weight percent of the composition and preferably at least about 1 weight percent. Amounts of surfactant of 60 weight percent or greater may be used. However, at such high levels cleaning times may increase considerably and elevated temperatures may be required to obtain satisfactory degreasing. The preferred range of surfactant is from about 1 to 50 weight percent, while the more preferred range is from about 10 to 35 weight percent of the composition. The most preferred surfactant range is from about 15 to 30 weight percent. The addition of surfactants in accordance with the present invention also serves to increase the flash point of the cleaning compositions over that of the cycloparaffins and branched paraffins alone. In contrast, boiling point is not significantly affected by the addition of surfactants to the cycloparaffins and branched paraffins. Thus, the boiling point of the present cleaning compositions may range from about 300 to 600^*F, and more preferably may range from about 350 to 550^βF.

The combination of cycloparaffins, branched paraffins and surfactants of the present invention provides for efficient removal of grease, grime, tars, oil and the like. The present cleaning compositions exhibit great affinity for greases and oils and are significantly more effective than traditionally employed cleaners.

For the purpose of the present invention, cleaning of a surface is defined in terms of the FTIR (Fourier Transform Infrared) reflectance spectrum of the surface. A surface is considered to have been cleaned when substantially all of the FTIR reflectance peaks corresponding to contaminates on the surface have been eliminated. Contact with the cleaning composition is preferably carried out with agitation. This can be accomplished either mechanically or ultrasonically or by spraying the composition onto the substrate. After contact with the cleaning composition, the substrate can be rinsed with solvents, such as water or low molecular weight alcohols such as isopropanol, compatible with the compositions and compatible with the substrate. Also, if desired the substrates can be dried, such as by blowing with hot or cold air.

The cleaning compositions of the present invention are generally employed at ambient temperature, but the efficiency of grease removal may be enhanced by heating the mixture slightly while remaining well below the flash point. Thus, elevated cleaning temperatures such as 100 or 150 °F may be employed.

In contrast to most of the known effective degreasers such as the freons, the chlorocarbons and conventional petroleum distillates, the presently disclosed cleaning compositions are substantially non-toxic and environmentally acceptable. As understood in the context of the present invention, these terms indicate that the materials used in the present cleaners are generally considered to be safe when measured against official U.S. Government criteria for hazardous materials. Typical measurements include animal ingestion tests for lethal dose 50 value and for carcinogenicity, flash point and CFC content.

The following non-limiting examples are provided to further illustrate the present invention.

Examples 1-6 illustrate the usefulness of cleaning compositions prepared according to the present invention for cleaning a variety of contaminants.

Example 1: A cleaning composition was prepared containing 80 volume percent (76.2 weight percent) Conoco XP-? and

20 volume percent (23.8 weight percent) dinonylphenoxypoly (ethyleneoxy) ethanol, a non-ionic surfactant sold by Rhone-Poulenc, Inc. under the name Igepal DM-530, having a density of 1.01. The cleaning composition possessed a tag closed cup (TCC) flash point of 172'F. A 1.5" x 5.0" piece of 2014 aluminum was contaminated by manually smearing the surface with 0.10g of Dow Corning #704 silicon oil. The aluminum was then dipped in the cleaning composition at room temperature, agitated mildly for 1 minute, rinsed in tap water, rinsed in deionized water and allowed to air dry for 1/2 hour. It can be seen from the Fourier Transform Infrared (FTIR) reflectance spectra of the contaminated surface (Fig. la) and the cleaned surface (Fig. lb) that essentially all of the peaks corresponding to contaminants on the surface were removed by the cleaning composition.

Example 2: A 1.5" x 5.0" piece of 2014 aluminum was contaminated by manually smearing the surface with 0.15g of drop hammer grease (heavy lubricant). The metal was then dipped in a cleaning composition as described in Example 1 at 40°C (104°F) for 5 minutes and agitated mildly. The piece was removed, tap water rinsed, rinsed in deionized water and then allowed to air dry for 1/2 hour. By comparing the FTIR reflectance spectra of the contaminated surface with the cleaned surface, it could be seen that there was essentially no contamination remaining on the surface.

Example 3: A 1.5" x 5.0" piece of 2014 aluminum was contaminated by manually smearing the surface with O.lδg of cosmolene (a heavy grease that is commonly used for corrosion protection). The cosmolene was allowed to dry overnight. The metal was then dipped in a cleaning composition comprising a mixture of 80 volume percent (76.2 weight percent) Conoco XP-15 and 20 volume percent (23.8 weight percent) Igepal DM-530 at 40°C (104'F) for 5 minutes and mildly agitated. The piece was then tap water rinsed, rinsed in deionized water and allowed to air dry for 1/2 hour. Surface cleanliness was demonstrated by comparing the FTIR reflectance spectra of the contaminated surface and the cleaned surface, showing that there were essentially no peaks remaining corresponding to cosmolene on the surface.

Example 4. A 1.5" x 5" piece of .2014 aluminum was contaminated by manually smearing the surface with O.lOg of CRC 2.26 (a lubricant/protector manufactured by CRC Company) and heated to 50^*C for 1/2 hour to remove residual solvent

(typically CRC 2.26 contains a certain amount of 1,1,1 trichloroethane). The piece was then dipped in a cleaning composition comprising a mixture of 80 volume percent (76.2 weight percent) Conoco XP-15 and 20 volume percent (23.8 weight percent) Igepal DM-530, at ambient temperature, agitated for 1 minute and removed. The piece was then rinsed in tap water, deionized water, and allowed to air dry for 1/2 hour. Surface cleanliness was measured by comparing FTIR reflectance spectra of the contaminated surface and cleaned surface, demonstrating that virtually no contamination peaks remained in the spectrum after treatment.

Example 5: A 1.5" x 5.0" piece of 2014 aluminum was contaminated by manually smearing the surface with O.lOg of Dow Corning #704 silicon oil. The piece was dipped in a cleaning composition comprising a mixture of 80 volume percent (76.2 weight percent) Conoco XP-15 and 20 volume percent (23.8 weight percent) Igepal DM-530, mildly agitated for 1 minute and removed. The piece was then tap water rinsed, rinsed in deionized water and then allowed to air dry for 1/2 hour. Excellent surface cleanliness can be seen after treatment by comparing the FTIR spectra of the contaminated surface, and the cleaned surface which had none of the contamination peaks seen before treatment. Example 6: Aluminum which had previously been coated with Iridite (an aluminum "conversion" coating) was examined in the as-received state by FTIR reflectance spectroscopy (Fig. 2a). The metal was then manually smeared with 0.10 g of Dow Corning #704 silicon oil, and again analyzed by FTIR reflectance spectroscopy (Fig. 2b). The metal was then dipped in a mixture of 80 volume percent (76.2 weight percent) Conoco XP-15 and 20 volume percent (23.8 weight percent) Igepal DM-530 at room temperature, mildly agitated for 1 minute and removed. The piece was tap water rinsed, rinsed in deionized water and then allowed to air dry for 1/2 hour. The extent to which surface cleanliness was restored after treatment is shown by comparing spectra of the as-received surface (Fig. 2a) and contaminated surface (Fig. 2b) with the cleaned surface (Fig. 2c).

Examples 7 and 8 demonstrate the effectiveness of cationic and anionic surfactants when formulated in accordance with the present invention.

Example 7: A cleaning composition was prepared with 80 volume percent (76 weight percent) Conoco XP-15 and 20 percent by volume (24 weight percent) of a cationic surfactant (trimethyl hexadecyl ammonium chloride) which mixes at all ratios to a slightly yellow, clear, homogeneous solution. This solution was compared side-by-side with a cleaning composition comprising 80 volume percent Conoco XP-15 and 20 volume percent Igepal DM-530 (non-ionic surfactant formulation). Two pieces of 6061 aluminum were each contaminated by smearing with 0.15g of drop hammer grease and placed in the respective cleaning compositions. Each composition was mildly agitated for 5 minutes and the metal removed. The pieces were then rinsed in tap water, deionized water and allowed to air dry. The effectiveness of the cationic surfactant was demonstrated using visual inspection, which showed that the rate of grease removal was indistinguishable in either solution, with each piece of aluminum being clean before the 5 minute removal. After drying, both pieces appeared to be clean visually with no apparent residues.

Example 8: A cleaning composition was prepared by mixing 1 volume percent (1.2 weight percent) sodium dodecylbenzene sulfonate (an anionic surfactant sold as Conoco C-550) with 99 volume percent (98.8 weight percent) Conoco XP-15 and heated to 40^βC (104^βF). A 1.5" x 5.0" piece of 6061 aluminum was contaminated with 0.15g of drop hammer grease on one side. The aluminum was then dipped for 5 minutes with mild agitation and removed from the cleaning composition. The aluminum was then thoroughly tap water rinsed, deionized water rinsed and allowed to air dry. Visual inspection showed that all grease had been removed from the aluminum surface by the composition.

Examples 9-12 compare the effectiveness of cleaners prepared in accordance with the present invention and the 1,1,1 trichloroethane (TCA) and a widely used water-based cleaner (Daraclean 282).

Example 9: Three pieces of 2014 aluminum were each contaminated with 0.15g cosmolene and let stand overnight. One piece was dipped in each of the following solutions: (1) a mixture of 80 volume percent (76.5 weight percent) Conoco XP-20 and 20 volume percent (23.5 weight percent) Igepal DM-530 having a tag closed cup flash point of about 215^*F, (2) 1,1,1 trichloroethane (TCA), and (3) Daraclean 282 (a water based alkaline cleaner sold by W.R. Grace Co.), all at 40^βC. After 5 minutes of mild agitation, the pieces were removed, thoroughly rinsed in tap water, deionized water and allowed to air dry. Excellent surface cleanliness of the pieces cleaned in liquids (1) and (2) was demonstrated by comparing the FTIR reflectance spectra of the surface before cleaning to after cleaning where all the contamination peaks had been eliminated. In contrast, the Daraclean 282 was unable to clean the surface of cosmolene as shown by comparable contamination peaks in the FTIR spectra of the surface before cleaning and after cleaning.

Example 10: Three pieces of 2014 aluminum were each contaminated with O.lOg CRC 2.26 corrosion inhibitor and allowed to stand at room temperature overnight. One piece was dipped in each of the following solutions: (1) a mixture of 80 volume percent (76.5 weight percent)

Conoco XP-20 and 20 volume percent (23.5 weight percent) Igepal DM-530, (2) 1,1,1 trichloroethane (TCA), and (3)Daraclean 282 (W.R. Grace Co.), all at 23^βC (73°F). After 1 minute of mild agitation, the pieces were removed, thoroughly rinsed in tap water and deionized water and then allowed to air dry. Good surface cleanliness with liquids (1) and (2) was seen by contaminant peak removal in the FTIR reflectance spectra after cleaning. However, Daraclean 282 was unable to completely clean the surface of CRC 2.26 as shown by contamination peaks in the FTIR spectra of the Daraclean 282 treated surface.

Example 11: Three pieces of 2014 aluminum were each contaminated with O.lOg of Dow Corning #704 silicon oil. One piece each was dipped in the following solutions: (1) 80 volume percent (76.5 weight percent) Conoco XP-20 and 20 volume percent (23.5 weight percent) Igepal DM-530, (2) 1,1,1 trichloroethane (TCA), and (3) Daraclean 282 (W.R. Grace Co.), all at ambient temperature (23^βC, 73^βF). After 3 minutes of mild agitation, the pieces were removed, thoroughly rinsed in tap water, deionized water and allowed to air dry. Surface cleanliness of the pieces cleaned in liquids (1) and (2) was seen by comparing the FTIR reflectance spectra before and after cleaning. The FTIR spectra of silicon oil was still present after treating with Daraclean 282, showing that it was unable to clean the surface. Example 12: Three pieces of 2014 aluminum were each contaminated by manually smearing with 0.15g of drop hammer grease. One piece each was dipped in the following solutions: (1) a mixture of 80 volume percent (76.5 weight percent) Conoco XP-20 and 20 volume percent (23.5 weight percent) Igepal DM-530, (2) 1,1,1 trichloroethane (TCA), and (3) Daraclean 282 (W.R. Grace Co.), all at 40'C (104^*F). After 5 minutes of mild agitation, the pieces were removed, thoroughly rinsed in tap water, deionized water and then allowed to air dry. Surface cleanliness of the pieces cleaned in the first two solutions was seen by comparing the FTIR reflectance spectra before and after cleaning where the contamination peaks were eliminated. Again, Daraclean 282 was unable to clean the surface of drop hammer grease as shown by retained contamination peaks in the FTIR spectra before and after cleaning.

Examples 13-15 show the use of varying amounts of surfactant in the cleaning formulations of the present invention.

Example 13: Conoco XP-15 without surfactant was used at 40^βC

(104^βF) to clean 0.15g of drop hammer grease from a piece of 2014 aluminum in 5 minutes with mild agitation. After thorough water rinsing and drying, an oily residue remained on the surface which could be wiped off but could not be removed with further water rinsing.

Example 14: A cleaning composition comprising a mixture of 1 volume percent (1.2 weight percent) Igepal DM-530 with 99 volume percent (98.8 weight percent) Conoco XP-15 at 40'C (104'F) was used to clean 0.15g of drop hammer grease from 2014 aluminum in 5 minutes with mild agitation. The piece was rinsed thoroughly in tap water, deionized water and allowed to air dry. No residue was present after drying. Example 15: A cleaning composition comprising a mixture of 50 volume percent (55.5 weight percent) Igepal DM-530 with 50 volume percent (44.5 weight percent) Conoco XP-15 at 40°C (104°F) was used to clean 0.15g of drop hammer grease from a piece of 2014 aluminum in 20 minutes with mild agitation. The piece was rinsed thoroughly in tap water, deionized water and allowed to air dry. No residue was present after drying.

Example 16: A cleaning composition was prepared by mixing 80 volume percent (75.8 weight percent) Conoco XP-10 with 20 volume percent (24.2 weight percent) Igepal DM-530 to form a homogeneous solution having a tag closed cup flash point of 115°F. A 1.5" X 5.0" piece of 6061 aluminum was contaminated with 0.15g of drop hammer grease on one side. The cleaning composition was heated to 40°C (104T) and the aluminum piece was dipped for 5 minutes with mild agitation. The aluminum was removed from the composition, thoroughly rinsed with tap water, deionized water and allowed to air dry. Visual inspection showed that no grease was left on the surface.

Many modifications and variations of this invention may be made without departing from its spirit and scope, as will become apparent to those skilled in the art. The specific embodiments described herein are offered by way of example only.

Claims

CLAIMS :

1. A cleaning composition comprising cycloparaffins, branched paraffins, and at least about 0.1 weight percent of a surfactant.

2. A cleaning composition according to claim 1, wherein the cycloparaffins comprise from about 15 to about 90 weight percent, the branched paraffins comprise up to about 60 weight percent, and the surfactant comprises from about 0.1 to about 60 weight percent.

3. A cleaning composition according to claim 1, wherein the cycloparaffins comprise from about 25 to about 85 weight percent, the branched paraffins comprise from about 5 to about 50 weight percent, and the surfactant comprises from about 1 to about 50 weight percent.

4. A cleaning composition according to claim 1, wherein the cycloparaffins comprise from about 30 to about 75 weight percent, the branched paraffins comprise from about 8 to about 45 weight percent, and the surfactant comprises from about 10 to about 35 weight percent.

5. A cleaning composition according to claim 1, wherein the cycloparaffins comprise from about 35 to about 70 weight percent, the branched paraffins comprise from about 10 to about 40 weight percent, and the surfactant comprises from about 15 to about 30 weight percent.

6. A cleaning composition according to claim 1, wherein the cycloparaffins contain from 6 to about 50 carbon atoms.

7. A cleaning composition according to claim 1, wherein the cycloparaffins contain from about 8 to about 30 carbon atoms.

8. A cleaning composition according to claim 1, wherein the branched paraffins contain from 4 to about 50 carbon atoms.

9. A cleaning composition according to claim 1, wherein the branched paraffins contain from about 8 to about 30 carbon atoms.

10. A cleaning composition according to claim 1, wherein the cycloparaffins and branched paraffins are obtained as distillate fraction from crude oil refining.

11. A cleaning composition according to claim 1, wherein the surfactant is selected from the group consisting of non-ionic, amphoteric, cationic and anionic surfactants, and combinations thereof.

12. A cleaning composition according to claim 1, wherein the surfactant is selected from the group consisting of dinonylphenoxypoly (ethyleneoxy) ethanol, sodium lauryl sulfate, tri ethyl hexadecyl ammonium chloride, linear alkyl benzene sulfonic acid, the sodium salt of N-coco betaamine propionate, sodium dodecylbenzene sulfonate, and combinations thereof.

13. A low toxicity, environmentally acceptable cleaning composition comprising from about 15 to about 90 weight percent cycloparaffin, from 0 to about 60 weight percent branched paraffin, and from about 0.1 to about 60 weight percent surfactant.

14. A cleaning composition according to claim 13, wherein the cycloparaffin comprises from about 25 to about 85 weight percent, the branched paraffin comprises from about 5 to about 50 weight percent, and the surfactant comprises from about 1 to about 50 weight percent.

15. A cleaning composition according to claim 13, wherein the cycloparaffin comprises from about 30 to about 75 weight percent, the branched paraffin comprises from about 8 to about 45 weight percent, and the surfactant comprises from about 10 to about 35 weight percent.

16. A cleaning composition according to claim 13, wherein the cycloparaffin comprises from about 35 to about 70 weight percent, the branched paraffin comprises from about 10 to about 40 weight percent, and the surfactant comprises from about 15 to about 30 weight percent.

17. A cleaning composition according to claim 13, wherein the cycloparaffin contains from 6 to about 50 carbon atoms.

18. A cleaning composition according to claim 13, wherein the cycloparaffin contains from about 8 to about 30 carbon atoms.

19. A cleaning composition according to claim 13, wherein the branched paraffin contains from 4 to about 50 carbon atoms.

20. A cleaning composition according to claim 13, wherein the branched paraffin contains from about 8 to about 30 carbon atoms.

21. A cleaning composition according to claim 13, wherein the cylcoparaffin and branched paraffin are obtained as distillate fraction from crude oil refining.

22. A cleaning composition according to claim 13, wherein the surfactant is selected from the group consisting of non-ionic, amphoteric, cationic and anionic surfactants, and combinations thereof.

23. A cleaning composition according to claim 13, wherein the surfactant is selected form the group consisting of dinonylphenoxypoly (ethyleneoxy) ethanol, sodium lauryl sulfate, trimethyl hexadecyl ammonium chloride, linear alkyl benzene sulfonic acid, the sodium salt of N-coco betaamine propionate, sodium dodecyl enzene sulfonate, and combinations thereof.

24. A cleaning composition according to claim 13, wherein the composition has a flash point of greater than 140'F.

25. A cleaning composition according to claim 13, wherein the composition has a boiling point of from about 300 to about 600^*F.

26. A cleaning composition according to claim 13, wherein the composition has a boiling point of from about 350 to about 550'F.

27. A cleaning composition according to claim 13, wherein the composition is water rinseable.

28. A cleaning composition according to claim 13, wherein the composition has low odor.

5 29. A cleaning composition according to claim 13, wherein the composition is capable of removing cosmolene.

30. A cleaning composition according to claim 29, wherein the composition is also capable of removing grease, oils and fats.

31. A cleaning composition according to claim 29, wherein the 10 composition is also capable of removing waxes and silicones.

32. A cleaning composition according to claim 29, wherein the composition is also capable of removing bitumen, tars and grime.

33. A method of cleaning a contaminated surface comprising contacting the surface with a mixture comprising cycloparaffins,

15 branched paraffins, and a surfactant for a sufficient time to solubilize surface contamination, and rinsing with a solvent compatible with said mixture.

34. A method according to claim 33, wherein the cycloparaffins comprise from about 25 to about 85 weight percent of the mixture, the

20 branched paraffins comprise from about 5 to about 50 weight percent of the mixture, and the surfactant comprises from about 1 to about 50 weight percent of the mixture.

35. A method according to claim 33, wherein the rinsing solvent is water.

25 36. A method according to claim 33, wherein the rinsing solvent is a low molecular weight alcohol.

37. A method according to claim 33, wherein said contacting is carried out at ambient temperature.

38. A method according to claim 33, wherein said contacting is carried out at elevated temperature.

39. A method according to claim 33, wherein said surface is contacted via spraying.

40. A method according to claim 33, wherein said surface is contacted via immersion.

41. A method according to claim 40, wherein mechanical agitation is applied during immersion.