CA2013431A1

CA2013431A1 - Microemulsion engine cleaner and degreaser

Info

Publication number: CA2013431A1
Application number: CA 2013431
Authority: CA
Inventors: Arpad M. Magyar; Joseph M. Russo
Original assignee: Individual
Current assignee: Pennzoil Quaker State Co
Priority date: 1989-03-30
Filing date: 1990-03-29
Publication date: 1990-09-30

Abstract

MICROEMULSION ENGINE CLEANER AND DEGREASER

Abstract of the Disclosure A biodegradable microemulsion comprising an organic solvent component, a coupling agent, a fatty acid, a biodegradable surfactant system, water and a basic component. The microemulsion is highly stable due to the surfactant system and its transparence to visible light. The microemulsion is effective to clean organic grease, oil and inorganic dirt from surfaces such as engines.

Description

2~13~31 MIC~OEMULSION ENGINE CLEANER AND DEGREASER

Technical Field The present invention relates to a cleaning composition useful to remove dirt and grease from surfaces such as automobile engines, garage floors, driveways and the like. In particular, the present invention relates to a microemulsion cleaning and degreasing composition and methods for use thereof.

Back~round Art A problem that has always existed in the automotive field is that automobile engines accumulate dirt, oil and grease. Such accumulations tend to prevent heat transfer and thus contribute to warmer running engines, which in turn decreases fuel-efficiency and increases the use of oil.
Another, frequently encountered problem is that ; such accumulations of dirt, oil and grease cause mechanics and "do-it-yourself" car owners to stain their clothing when working on such engines.
Various preparations and techniques have been used over the years to clean such engines without the need fox removing the engine from the vehicle and submerging it in solvent. For example, hose flushing~ physical scraping, and application of various liquids have all been utilized in the process of degreasing or cleaning automobile engines.

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One of the key problems in cleaning automobile engines with known chemical solvent prepaxations has been that the solvents used drip or run-off quickly before the dirt, oil and grease accumulations can be satisfactorily emulsified and lifted. The thin, rlmny nature of such middle and upper distillates such as kerosene or naphtha make them particularly less effective on the vertical and undersides of the engine, although such solvents perform well when ~he engine is removed and submerged in such solvents.
Engine cleaners and degreasers may be generally classified as all-solvent base types, all-water based types~ which generally include detergents, and combinations of solvents with aqueous detergents.
All-solvent based engine degreasers have been marketed for a number of years. These all-solvent based degreasers include hydrocarbons and hydrocarbon blends such as kerosene, fuel oil, naphtha, and the like. The use of such solvents alone, which has been practiced fox years, is very costly, generally presents pollution disadvantages and the efficiency is not always sufficient. In use, these all-solvent based degreasers are usually sprayed on the automobile engine by squeeze bottle, aerosol pack, or pump delivery. Before the solvent runs off the engine, it is sprayed or flushed with water which forms an emulsion with the solvent to give better cleaning action.
All-solvent based cleaners which incorporate surfactant systems have been found to be effective on greasy deposit removal but tend to leave inorganic, muddy deposits on surfaces. This is a limitation caused mainly by the solubility characteristics of the various emulsifiers and detergents. A solvent based product can 3 2~13~3~

incorporate only relatively low hydrophilic-lipophilic balance (HLB) surfactants with good emulsifying but poor wetting characteristics.
All-water based products are also known which have good wetting ability and cleaning power. These all-water based products generally contain water-soluble detergents and, while being effective on removing dirt, are not as effective on oil and grease removal as or~anic solvents.
A combination of solvents and detergents is also known in the prior art (U.S. Patent 3,717,590, East German Patent DD 0,220,042 and Sweden SE 8 r4~11115) /
but these either are not microemulsions, or incorporate environmentally undesirable components, such as 15 polyoxyethylated phenols, phosphates, highly aromatic solvents, etc.
Cleaning and degreasing compositions which are a combination of solvents and aqueous detergents generally include components of both all-solvent type degreasers and all-water based products together with a surfactant system that enables the mixing of these two types of cleaning and/or degreasing compositions.
The surfactant systems generally include two or more surfactants, each selected to have a suitable or 25 compatible HLB to insure the homogeneity and stability of the overall composition. The surfactants systems usually include both low HLB surfactants that are mGre easily incorporated into solvent components and high HLB surfactan~s that are more easily incorporated into aqueous components.

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Particularly in emulsion-type cleaners and degreasers, the surfactant systems are selected to enable formation of the emulsions as well as stabilize the emulsions over the period of time in which they are stored and/or utilized.
Heretofore emulsion-type cleaning and degreasing compositions have relied on surfactant systems that are highly specific for use with the other components utilized in the overall emulsion. In this regard, the surfactants themselves or other components for which the surfactants are selected to be compatible with have not been biodegradable. Other known emulsion cleaners and degreasers are either not microemulsions, and therefore are neither as stable or effective as microemulsions, or are not sufficiently transparent so as to be stable when exposed to wavelengths of visible light.
U.S. Patent No. 4,302,365 to Holmgren et al.
describes an emulsion type engine degreaser which combines both a solvent and water component, but which is an opaque, viscous emulsion with the inherent instability problems of non-microemulsion type products.
U.S. Patent No. 4,568,480 to Thir et al. describes a microemulsion which is transparent to visible light but which is disadvantageous in that alkoxylated phenol derivatives are used in the surfactant system. These phenol derivatives are biodegradable only to the phenol radical so that such products are undesirable ~or release to the environment since the phenol is toxic.

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The present invention is an improvement over the prior known microemulsion cleaning and degreasing compositions, and provides a highly stable, biodegradable microemulsion transparent to visible light and which demonstrates superior cleaning and degreasing abilities over the prior art.

Disclosure of the Invention It is accordingly one object of the present invention to provide a novel emulsion for cleaning and degreasing solid surfaces.
A further object of the present invention is to provide a highly stable and biodegradable microemulsion cleaning and degreasing composition which is transparent to visible light.
Another object of the present invention is to provide for a method for producing the novel cleaning and degreasing emulsion composition of th~ present invention.
A still further object of the present invention is to provide means for applying and utilizing the novel cleaning and degreasing composition of the present invention.
An even further object of the present invention is to provide a method for cleaning and degreasing solid surfaces such as internal combustion engines, garage floors, driveways and the like.
According to the present invention, there is provided a cleaning and degreasing composition which is in the form of a biodegradable microemulsion which has a particle size sufficiently small to be transparent to visible light and form a stable emulsion.

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Also provided by the present invention are means for applying and utilizing the microemulsion and a method for cleaning and degreasing solid surfaces which utilizes the microemulsion of the present invention.
The invention also provides a composition which is effective to clean oily/dusty/muddy surfaces through solvent and detergent dual action.
In satisfaction of the foregoing objects and advantages, the present invention provides a biodegradable microemulsion cleaning and degreasing composition which comprises an organic solvent component, a coupling agent, a fatty acid, a biodegradable surfactant system, water and a basic component.
Also provided by the present invention is a method for cleaning dirt, grime and grease from a solid surface such as an automotive engine which comprises applying to the engine a biodegradable microemulsion cleaning and degreasing composition which comprises an organic solvent component, a coupling agent, a fatty acid, a biodegradable surfactant system, water and a basic component, permitting the composition to remain on the solid surface for a sufficient period to penetrate the dirt, grime and grease on the solid surface, and thereby loosen and dissolve the dirt, grime and oil, and then flushing the surface with water to remove the mixture of said composition and dirt, grim and grease, and effect cleaning o the solid surface.

Best Mode for Carr~ina out the Invention The cleaning and degreasing composition of the present invention generally includes between about 30%
and about 60% by weight of a organic solvent, 7 20:13~L31 preferably a hydrocarbon solvent, between about 5% to about 15% by weight of a coupling agent, between about 5~ and 15% by weight of a fatty acid, between about 5%
and about 20% by weight of a biodegradable surfact~nt system, between about 20% and about 50% by weight of water, and up to about 5% by weight of a basic component.
This cleaning and degreasing composition of the invention is prepared by emulsifying an organic solvent, e.g., a hydrocarbon such as kerosene, with water to form an emulsion of a very small particle size. The particles formed are smaller than the wavelength of light which thereby makes the product transparent and extremely stable. There is also an increase in viscosity over all-solvent based products which causes the product to cling better and longer to vertical surfaces. This also improves cleaning action by enabling longer contact time. When applied to hot engines, the water tends to simmer and steam off the engine sllrfaces thereby contributing to the cleaning action by increased convection.
A combination of a solvent with water is used to form the microemulsion, the microeml~lsion also incorporating both high and low HLB surfactants, emulsifiers, and wetting agents. The amount of water, howe~er, is characteristically limited to a range up to about 35 wt.%, because exceeding this value results in milky emulsions. These white milky emulsions have much larger particle sizes and have much lower cleaning powers. The present microemulsions are convenient in that they do not have to be shaken before application because a two-phase system does not exist.

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The microemulsion cleaning and degreasing formulation of the present invention is formed by combining together the organic solvent component, a coupling agent, a fatty acid, a biodegradable S surfactant systeml water and a basic component.
The organic solvent functions as a vehicle to carry off grease. In this regard, the microemulsion formulation incorporates the degreasin~ characteristics similar to all solvent based degreasers. Any suitable, middle or upper petroleum distillant solvent may be utilized; however less volatile hydrocarbon solvents are preferxed, e.g., kerosene, because o~ safety considerations.
The coupling agent functions as an emulsion stabilizer, a dirt penetrant, a powerful solvent, and an agent to aid in bringing the organic solvent, e.g., kerosene, into solution. A coupling agent found to be particularly useful for purposes of the present invention is an alkylene glycol ether such as a dipropylene glycol monomethyl ether, which is available commercially under the tradename Arcosolv DPM.
The preferred fatty acid component is an aliphatic fatty acid in the formulation of the present invention.
Preferred fatty acids include tall oil fatty acids.
The atty acid is reactive and forms a soap, e.g.
potassium soap, as a result of reaction with the caustic component. Particularly suitable fatty acids include oleic acids, linoleic acids and mi~tures thereof but including any fatty acid having from about 8 to 30 carbon atoms.
The surfactant system utilized includes at least two nonionic surfactants, ~referably ethoxylated aliphatic alcohols such as those sold under the tradename Neodol by Shell. A mixture of Neodol 91-6 9 ~0~3~

and Neodol 91~2.5 (C6 -Cl1 ethoxylated alcohols) is preferred. Each surfactant is biodegradable and has differenk HLB factors. These nonionic surfactants together function to prevent redeposition of materials removed from the surface and maintain the stability of the microemulsion.
The basic component used in the present formulation is selected to react with the fatty acid to produce a soap for cleaning inorganic dirt. Suitable basic components include alkali metal and ammonium hydroxides such as potassium hydroxide, sodium hydroxide, ammonium hydroxide, and mixtures thereof as well as organic amines and alkanolamines, e.g., ethanolamine. In a preferred embodiment potassium hydroxide and ethanolamine were found to be ideal basic component. The base is used as an aqueous solution having a concentration of 10 to 60 wt%.
The microemulsion is prepared by forming a first mixture (Part A) which includes the organic solvent component, the coupling agent, the fatty acid and the biodegradable surfactant system. To this first mixture is added a second mixture (Part B~ which includes the water and basic component. In forming the emulsion, the first mixture (Part A) is prepared and the second mixture (Part B) is slowly added thereto while heating the overall mixture to between about 50 C to 60 C, until a stable emulsion is formed. The pH of the final emulsion is between about 8.5 and lQØ
The microemulsion cleaner of this invention incorporates all the desirable characteristics of all-solvent based products as well as inorganic dirt removing characteristics of water-based cleaners.

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~dditionally, the present formulation contains environmentally compatible ingredients and is completely biode~radable.
In addition to the above discussed components, a wide variety of solvents, emulsifiers, wetting agents, detergents, co-solvents, coupling agents, pH and viscosity modifiers, corrosion preventatives, etc. can al~o be used in conjunction with the microemulsion to provide specific features.
The formulation of the present invention may be used to remove dirt, grime and grease from a variety of surfaces such as automobile engines, garage floors, driveways and the like. In this regard, the present invention satisfies a long felt need for an engine degreaser which would be effective on greasy deposits as well as on dusty road film.
For convenience of use, the present formulation may be incorporated into a spray pump, squeeze bottle, or an aerosol can and the jet action of the spray will contribute to the cleaning performance by increasing penetration into the dirt and dislodging it. For further convenience, a spray-anyway valve can be incorporated to allow access to otherwise difficult to reach areas.
In a preferred embodiment, the hydrocarbon solvent is selected to act as a vehicle to carry off grease. In this regard, kerosene has been found to be particularly suitable.
The coupling agent has been selected to act as a dirt penetrant, a powerful solvent as well as an aid in bringing the hydrocarbon solvent, e.g., kerosene, into solution. A coupling agent found to be particularly useful for purposes of the present invention is dipropylene glycol monomethyl ether.

11 2013~31 The fatty acid preferably used in the present formulation is a tall oil fatty acid. Additionally, the fatty acid forms a soap, e.g. potassium soap, as a result of reaction with the basic component.
Particularly suitable fatty acids include oleic acids, linoleic acids, linolenic acids, and mixtures thereof.
The surfactant system includes at least one and preferably two or more nonionic surfactants which help to prevent redeposition of loosened material and maintains the emulsion sta~ility. Particularly suitable surfactants include ethoxylated aliphatic alcohols.
The basic component used in the present formulation is selected to react with the fatty acid to produce a soap as discussed above and may include potassium hydroxide, sodium hydroxide, ammonium hydroxide, ethanolamine and mixtures thereof. A
preferred base component is potassium hydroxide or ethanolamine.
The composition is used by spraying it on the surface to be cleaned such as an automobile engine, including hot engines. The composition should then be allowed to stay in place on the surface for an effective period to loosen the dirt, gxime and/or grease, e.g., about 5 to 30 minutes. Usually about lO
minutes is sufficient.
During this period the solvent and detergents penetrate, dissolve and loosen the dirt, grime and grease on the surface. The treated surface should then be flushed with water as by a garden hose in order to remove the mixture of the composition and the loosened and dissolved material removed from the solid surface.
As the mixture is washed off, the emulsifier mixture will cause both the removed material and the solvent to 12 2~3~3~

be washed off the solid surface. The result is a solid surface from which both the dirt, grim and/or grease and the treating composition have been removed.
The following examples are presented to illustrate the invention which is not intended to be considered as being limited thereto. In the examples and throughout percentages are by weight unless otherwise indicated.

EXAMP~E 1 Part ~ Wt. %
Kerosene 42.9 Dipropylene glycol monomethyl ether 10.9 Neodol 91-6 4.9 Neodol 91-2.52 1.9 Acintol FA-33 10.6 1. Neodol 91-6 is a C -C 1 ethoxylated alcohol having an average of 6 ethy~ene oxide groups and is available from Shell Development Company.
2. Neodol 91-2.5 is a C -C 1 ethoxylated alcohol having an average of 2.5 eth~ en1e oxide groups and is available from Shell Development Company.
3. Acintol FA-3 is a fatty acid mixture comprising mainly oleic and linoleic acid and is available from Arizona Chemicals.
Part B
Water 26.0 Potassium hydroxide (45% in H20) 2.8 The emulsion is clear and s~able. Its cleaning performance is equivalent to all-solvent based cleaners on greasy deposits and superior on muddy road film type dirt.

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Part A Wt.%
Dipropylene glycol monomethyl ether 9.0 Dodecylbenzene sulfonic acid 1.5 Atlas N601 4.0 Neodol 91-2.52 18.0 Kerosene 46.63 1. Atlas N60 io naphthenic mineral oil having a viscosity a 60 @ 100 F and is available from Pennzoil Products Company.
2. See Example 1.

Part ~
Water 20.68 Sodium hydroxide 0.19 The product is a clear emulsion which cleans in a manner comparable to all-solvent based products available commercially.

EXAMP~E 3 Part A Wt. %
Dipropylene glycol monomethyl ether 9.7 Neodol 91-6* 6.0 Neodol 91-2.5* 3.0 Oleic acid 8.4 Kerosene 42.0 *See Example 1 14 2~`3~3~

Part B
Water 29-0 Ammonium hydroxide 1.9 The product is a clear emulsion whi.ch clean~ in a manner comparable to the best solvent based products available commercially.

Part A Wt. %
Dipropylene qlycol monomethyl ether 9.7 Oleic acid 9.7 Neodol 91-6l 5.8 Surfynol 440 l.9 Kerosene 41.9 1. See Example 1.
2. Surfynol 440 is a mixture of acetylenic diols.

Part B
Water 29.1 Ammonium hydroxide 1.9 The product is a clear microemulsion which cleans well but performance is somewhat inferior to the formulation of Example l.

Part A Wt. %
Kerosene 48.5 Ethomeen 18/251 2 Alkaril chemical emulsifier2 3 1S 2~343~

1. Ethomeen 18/25 is a polyethyloxylat~d amine available from Akzo.
2. ~lkril chemical emulsifier is a proprietary alkanolamide of Alkaril Chemicals.
Part B
Water 46.S

The product is a clear microemulsion which cleans reasonably well but performance is inferior to formulation of Example 1.

Part A Wt. %
Kerosene 42.85 Dipropylene glycol monomethyl ether 9.56 Acintol FA-3* 11.28 Neodol 91-6* 4.96 Neodol 91-2.5* 1.94 Part B
Water 25.78 Potassium hydroxide 3.63 *See Example 1.

This emulsion has a p~ between about 8.5 and 10.0 and is clear and stable. Its cleaning perfo~mance is equivalent to all-solvent based cleaners on greasy deposits and superior on muddy road film type dirt.
From the above examples it is seen that the microemulsion formulation of the present invention is characteriz0d as having superior cleaning and degreasing abilities as well as being stable and biodegradable.

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Although the invention has been described with reference to particular means, materials and embodiments, from the foregoing description, one skilled in the are can ascertain the essential characteristics of the present invention and various changes and modification may be made to adapt the various uses and characteristics thereof without depaxting from the spirit and scope of the present invention as described in the claims that follow.

Claims

1. A biodegradable microemulsion cleaning and degreasing composition which comprises a organic solvent component, a coupling agent for dirt penetration and to cause the solvent to solubilize, a fatty acid, a biodegradable surfactant system, water and a basic component.

2. A biodegradable microemulsion according to claim 1, wherein said organic solvent component comprises a middle or upper petroleum distillate.

3. A biodegradable microemulsion according to claim 2, wherein said hydrocarbon solvent component comprises kerosene.

4. A biodegradable microemulsion according to claim 1, wherein said coupling agent comprises dipropylene glycol monomethyl ether.

5. A biodegradable microemulsion according to claim 1, wherein said fatty acid comprises a mixture comprising oleic and linoleic acid.

6. A biodegradable microemulsion according to claim 5, wherein said fatty acid is selected from the group consisting of tall oil fatty acids, oleic acids, linoleic acids and mixtures thereof.

7. A biodegradable microemulsion according to claim 1, wherein said surfactant system comprises at least two surfactants.

8. A biodegradable microemulsion according to claim 7, wherein said at least two surfactants comprise nonionic surfactants.

9. A biodegradable microemulsion according to claim 8, wherein said nonionic surfactants comprise ethoxylated aliphatic alcohols.

10. A biodegradable microemulsion according to claim 1, wherein said basic component is an alkali metal hydroxide, an amine or an alkano/amine.

11. A biodegradable microemulsion according to claim 10, wherein said basic component is selected from the group consisting of potassium hydroxide, sodium hydroxide, ammonium hydroxide, alkyl amine, alkanolamine and mixtures thereof.

12. A biodegradable microemulsion according to claim 11, wherein said basic component comprises potassium hydroxide or ethanolamide.

13. A biodegradable microemulsion according to claim 1, wherein said microemulsion has a sufficiently small particle size to be transparent to visible light.

14. A biodegradable microemulsion according to claim 1, wherein said water comprises up to about 35%
by weight of said microemulsion.

15. A biodegradable microemulsion cleaning product which comprises the biodegradable microemulsion of claim 1 incorporated into a spray pump, squeeze bottle, or aerosol applicator.

16. A method of cleaning and degreasing a solid surface which comprises applying to said solid surface the microemulsion of claim 1, permitting the microemulsion to remain on the solid surface for an effective period, and then washing or flushing the surface with water.

17. A method of cleaning a solid surface according to claim 17 wherein said solid surface comprises an engine, a garage floor or a driveway.

18. A method of cleaning a solid surface according to claim 18 wherein said solid surface is an engine which has been heated prior to applying said microemulsion.

19. A biodegradable microemulsion cleaning and degreasing composition which comprises between about 30% and about 60% by weight of a hydrocarbon solvent, between about 5% and about 15% by weight of a coupling agent, between about 5% and about 15% of a fatty acid, between about 5% and about 20% by weight of a surfactant system, between about 20% and about 50% by weight water, and up to about 5% by weight of a basic component.