EP0683812A1

EP0683812A1 - Cleaning

Info

Publication number: EP0683812A1
Application number: EP94906311A
Authority: EP
Inventors: Neil Rogers; Paul Withers
Original assignee: Individual
Current assignee: Individual
Priority date: 1993-02-12
Filing date: 1994-02-11
Publication date: 1995-11-29
Also published as: CA2155977A1; WO1994018300A3; WO1994018300A2; AU6006994A; GB9302869D0

Abstract

An aqueous based cleaning composition, e.g. for textiles, comprises in addition to a major part of water, a surface active agent, a base and an organic acid, or a salt of a base and an organic acid, and a dispersed phase of a hydrocarbon. The hydrocarbon is preferably a terpene, most preferably limonene. The composition may be used for cleaning textile articles in a process which involves directing ultrasonic waves at the articles to be cleaned.

Description

CLEANING

This invention relates to cleaning. The invention provides a composition for use in cleaning, a process for the preparation of the composition and a method of cleaning.

Textile materials, for example garments or curtains, are often cleaned using a well-known process of "dry cleaning". In dry cleaning, an article to be cleaned is immersed in a cleaning fluid ^"and agitated to dislodge particles of dirt and grease. The cleaning fluid aids removal of the dirt and grease from the article and subsequently aids dispersion and sequestration of the dirt and grease in the cleaning fluid.

Some problems with dry cleaning are associated with the cleaning fluids used. The most widely used cleaning fluids are highly flammable hydrocarbons and chlorinated hydrocarbons, particularly tetrachloroethene. The use of such highly inflammable solvents, which also have low flash points, presents a significant fire risk and, accordingly, the solvents must be handled very carefully under strictly controlled conditions. Also, the use of the solvents presents an environmental hazard and a health risk to personnel, since they are often carcinogenic. Furthermore, the solvents are highly volatile and may be absorbed through the skin or inhaled. Thus, it would be preferable to use a less problematic solvent in cleaning.

It is an object of the present invention to alleviate at least some of the aforementioned problems.

According to a first aspect of the present invention there is provided an aqueous based cleaning composition comprising, in addition to a major part of water, a surface active agent, a base and an organic acid, or a salt of a base and an organic acid, and a dispersed phase of a hydrocarbon.

According to a second aspect of the present invention, there is provided a process for the preparation of the cleaning composition of the first aspect, the process comprising admixing a major proportion of water with minor proportions of a surface active agent, a base and an organic acid, or a salt of a base and an organic acid, and a hydrocarbon.

It has been found that the cleaning composition is effective for removing dirt and grease from many articles, for example, from textile materials. The composition is particularly advantageous in comparison to the solvents used in dry cleaning described above since a major portion of the composition is water and only a minor portion is comprised by potentially flammable and/or toxic hydrocarbon. Thus, the composition may - be more environmentally and toxicologically acceptable compared to the known dry cleaning solvents. The cleaning composition is also effective for cleaning non-textile materials, for example work surfaces made of wood or plastics material. Other uses of the cleaning composition are in metal degreasing and wool scouring.

The preferred hydrocarbons for use in the cleaning composition of the invention are terpenes which are built up of isoprene (C_£H₈) units. Terpenes are classified into open chain, monocyclic, bicyclic, sesqui and polyterpenes and any such form of terpene may be used in the composition of the invention. Most preferably the terpene is limonene which has the chemical name 4-isopropenyI-l- methylcyclohexene (C₁₀H₁₆). Limonene may be provided by D'limonene which is of citrus origin. D'Limonene generally contains at least 95% 4-isopropenyl-l-methylcyclohexene. Another name for D'Limonene is stripper oil (see also Food Chemicals Codex, 1981). D'Limonene is mostly composed of mono Terpene Hydrocarbons.

Synonyms for D'Limonene include (+)-Carvene, Citrene, Limonene, 1,8-p-Menthadiene. The preferred source of D'Limonene is Brazilian.

Other terpene hydrocarbons derived form the essential oils extracted from the leaves, blossoms, fruits and barks belonging to the family Coniferae and Myrtaceae and the genus Citrus may also be used in place of D'Limonene. The essential oils comprise mixtures of Terpenes which have the empirical formula (C₅H₈)_n and oxidation products of these.

Other hydrocarbons which may be used in compositions of the invention include carrotenes, pine oil, white spirit, paraffin (kerosene), iso-paraffins, and petroleum distillates. These products may also be in the form of their odourless alternatives.

White spirit (C.A".S. No. 8052-41-3) includes a mixture of saturated and unsaturated hydrocarbons and, optionally, aromatic hydrocarbons and the invention covers the constituents of the mixture singularly or in combination. Where the white spirit includes aromatic hydrocarbons, preferably it comprises 15-20% of aromatic hydrocarbons. Aromatic hydrocarbons include C₆-C₁₂ aromatics. Preferred aromatic hydrocarbons include C₇ (toluene), C₈ and C_g aromatic hydrocarbons. Turpentine is also a mixture of hydrocarbons, for example cyclic terpene hydrocarbons, primarily α-pinene and the invention of the first aspect covers the constituents of the mixture singularly or in combination.

It should also be understood that he term 'hydrocarbon' as used herein is also intended to cover substituted hydrocarbons, e.g. halogenated hydrocarbons such as chlorinated hydrocarbons. The amount of hydrocarbon present in the composition is preferably less than 10%, more preferably less than 5% by weight of the total weight thereof. Even more preferably the amount of hydrocarbon is less than 3% and ideally less than 2% on the same weight basis.

The composition further comprises an organic acid and a base, or a salt of these two components. The organic acid should be a weak acid. Most preferably the organic acid is a water soluble carboxylic acid, ideally one having 6 or less carbon atoms. It is also preferred that the organic acid is a monocarboxylic acid. Thus preferred acids include formic acid, propionic acid, butyric acid, valeric acid, and caproic acid. The most preferred acid for use in the composition is glacial acetic acid although other commercial grades commonly known as ethanoic acid, technical grade, vinegar acid may also be used. It is however possible to use higher functionality acids, e.g. citric acid.

If free acid is included in the composition then it is preferably incorporated therein in an amount of less than 10%, more preferably less than 5%, and most preferably less than 2%, by weight of the total weight of the composition.

The base is preferably ammonia used in the form of an aqueous solution (e.g. products known as ammonia solution, aqueous ammonia, ammonia liquor, and ammonium hydroxide. Preferred ammonia solutions are these known as '880 ammonia' having an ammonia content of 33- 34%. The ammonia solution should be a clear, colourless solution free from suspended matter and residual deposits.

Bases other than ammonia may also be used, e.g. alkali metal hydroxides such as sodium or potassium hydroxide. Other bases which may be used include alkanolamines.

The amount of base used is preferably less than 10%, more preferably less than 5% by weight of the composition, most preferably less than 2% by weight. Any amount of base relative to acid may be used.

It is also possible to incorporate in the composition a salt of a base and an organic acid. In this case the salt will generally be added instead of the free acid and base, but may be added as a supplement thereto. Preferred salts are those derived from any of the aforementioned bases and organic acids. Most preferred are the ammonium salts of organic carboxylic acids, e.g. ammonium acetate.

The salt, if used, is preferably added in an amount of less than 10%, more preferably less than 5%, e.g. less than 2%.

The actual acid/base combination or salt used in the composition may be governed by the end use thereof. Thus if the composition for use is cleaning textile materials then the acid is preferably acetic acid and the base is preferably ammonia. Alternatively ammonium acetate may be used as salt. For cleaning of leather it is preferred that the acid is formic acid and the base is ammonia. Alternatively ammonium formate may be used as a salt.

Water from any source may be used in the composition. It is, however, preferred to use soft water or distilled water. The recommended water type is distilled, although this may be replaced with de-ionised or waters up to a Hardness of 30ppm calcium as calcium carbonate. Generally the amount of water present will not be less than 60%, more usually not less than 70% by weight.

The detergent is adapted to disperse the hydrocarbon-containing solvent in the water. Any anionic and/or a non-ionic surfactant may be used. The detergent is preferably biodegradable. The detergent suitably comprises a long chain (e.g. C₈-C _{1 6}) sulphonic acid (or salt thereof), for example a long chain alkyl benzene sulphonate such as dodecyl benzene sulphonate which may be in combination with a fatty alkylamide. Other surfactants include olefin sulphonates and paraffin sulphonates. The amount of surface active agent in the composition is preferably less than 10%, more preferably, less than 5%, e.g. less than 2%.

The surfactant may be added as formulation which contains components other than the surfactants e.g. water and terpene. The surfactant formulation may for example contain at least one surface active agent together with a monoethanolamine, a glycol ether, D'limonene, and/or water. One such formulation (referred to in Example 1 below as surfactant Formulation A) comprises the following components.

PREFERRED % WEIGHT D'Limonene 18.50

Water 52.00

Monoethanolamine (MEA) 3.00

Dodecylbenzene sulphonic acid (DBSA) 16.50

Butyl diglycol ether (BDE) 10.00

If such a surfactant formulation, the D'limonene may exist as an emulsion in the water, the emulsified phase having a droplet size of 1 micron or less.

The D'Limonene present in this 'surfactant formulation' may provide part of the total D'limonene for the composition of the invention.

The monoethanolamine in the above formulation is preferred but may be replaced by any alkanolamine. The butyl diglycol ether may be replaced with any suitably commercially available glycol ether such as diethylene glycol monomethyl ether, diethylene glycol monobutyl ether, and ethylene glycol monoethyl ether.

Additionally, the 'surfactant formulation' may contain any one or combinations of the following components either in addition to or as at least a partial replacement for the MEA, DBSA and/or BGE, namely lauryl-myristyl ethoxylates, cetyl-stearyl ethoxylates, cetyl-oleyl alcohol ethoxylates, fatty alcohol ethoxylates, oxo alcohol ethoxylates, branched oxo alcohol ethoxylates, isotridecyl alcohol ethoxylates, 2- ethylehaxanol ethoxylates, nonylphenol ethoxylates, octylphenol ethoxylates, low foaming, biodegradable alkoxylates, amine oxides, alkylolamides, alcohol ethoxy sulphates, or castor oil ethoxylates or propoxylates. However, the total amount of MEA, DBSA and BDGE present in the formulation may be replaced by the same total amount of one or more compounds as listed in the previous sentence.

Formulations in accordance with the invention may contain a perfume or a reodourant, particularly if it is desired to suppress the aroma of the hydrocarbon. A reodourant will be particularly desirable in the case where the hydrocarbon is D'Limonene.

The preferred reodourant is a complex blend of essential oils and aromatic plant extract compounded with synthetic aroma chemicals.

Preferably the pH of a cleaning composition for use in cleaning textile articles is 5.5-6.5. It is however possible to use pH values outside this range, and this may be desirable for other cleaning applications. Thus for example the pH may be greater than 7. The pH may for example be greater than 9, e.g. in the range 9 to 12.

A preferred composition in accordance with the invention comprises

Carboxylic Acid (e.g. acetic 1-2% by weight or formic)

Base (e.g. ammonia) 1-2% by weight

Hydrocarbon 0.5-1.5% by weight

Surface Active Agent 1-2% by weight

Reodourant 0.1-1% by weight

Water Balance

Generally the amount of water will not exceed 95.2%.

The formulations may be mixed together in any suitable apparatus for producing the emulsified phase of the hydrocarbon, which will typically have a droplet size of 10-30 microns. It is preferred, but not essential, that the components are added to the water in the following order, namely acid, base, hydrocarbon, surface active agent, reodourant.

Formulations of the type exemplified above may be supplied to the end use. It is however also possible for the end user to be supplied with various component of the formulation and to effect the final mixing/dilution as required. Thus, for example, it is possible to produce a formulation comprising.

Water 85% by weight

Acid 5% by weight

Base 5% by weight

Surface Active Agent 5% by weight Such a formulation may be diluted, by the end user, with 80% of water and then 1% by weight of hydrocarbon and re-odourant. Dispersion of the hydrocarbon may take place in the apparatus in which the cleaning composition is used, e.g. laundry apparatus.

In addition to the components discussed above, the composition may include further components selected from the following.

1. Thickening agents such as a xanthan polysaccharide compounded singly or with synthetic or natural thickeners such as cellulose ethers, locust bean gum, starches, sodium alginate etc. Such thickening agents would serve as an acid to reduce the effect of mechanical damage during use of the composition for washing textile articles.

2. An optical brightening agent.

3. A cationic surfactant for providing softening fabric conditioning.

4. An amphoteric -surface active agent for improved cleaning performance.

5. Preservatives.

6. Glycerine.

7. Fat-liquoring agent (for leather).

8. An amine for preventing corrosion when the composition is to be used for metal degreasing.

According to a third aspect of the present invention, there is provided a method of cleaning an article, the method comprising treating the article with a cleaning composition according to the first aspect of the invention.

The method may comprise immersing the article, for example, a textile article, in the cleaning composition. The method of the third aspect of the invention as applied to the cleaning of textile article has the significant advantage over conventional washing processes using water (e.g. in conjunction with detergent) in that it is found that the textile articles dry considerably more rapidly. Preferably agitation means is provided for aiding cleaning.

According to a fourth aspect of the present invention, there is provided a method of cleaning a textile article, the method comprising arranging the textile article in a container which contains a cleaning composition in accordance with the first aspect of the invention and using ultrasonic waves to clean said article in said container.

Preferably, ultrasonic waves are directed at the article in the container.

Preferably, the direction of travel of the ultrasonic waves is varied during said method of cleaning.

The method of the fourth aspect of the invention may provide a method of cleaning which is improved over other known methods, in particular the dry cleaning method described above. For example, cleaning is achieved without physically agitating the textile articles. Such physical agitation may reduce detrimental effects on the shape and/or texture of the articles. The time that the article must spend in said container may be significantly less than in the dry cleaning method and, furthermore, the time that must be spent finishing the cleaned article may also be reduced.

The method suitably uses a cleaning apparatus (which provides s fifth aspect of the invention) which comprising a treatment fluid container in which a textile article to be cleaned may be immersed and ultrasonic cleaning means arranged to direct ultrasonic waves suitably at said textile article when in said container, so as to clean said textile article. The cleaning apparatus may include holding means for a textile article. Movement means may be provided for moving a textile article held by said holding means from a first position in which it is not arranged within said container to a second position in which it is arranged with said container. Said holding means and/or said movement means are preferably integral components of said apparatus.

The apparatus may include a plurality of said holding means and/or said movement means. Said plurality are preferably arranged to be selectively positioned adjacent said container so that a selected article to be cleaned may be arranged in said container. Said plurality of holding means and/or movement means may be provided on a conveyor system. The conveyor system preferably comprises an endless conveyor.

The apparatus may include a plurality of containers each containing a cleaning-composition. The method may include arranging the article to be cleaned in each container during said method of cleaning. One of said containers may include a composition arranged to rinse the textile article. When provided, said holding means and/or said movement means are preferably adapted to arrange selectively the article to be cleaned in each container.

Filtration means may be provided for filtering the cleaning composition in one or each container.

The apparatus may include heating means for heating the cleaning composition in said bath. Suitably, therefore, the method includes heating the cleaning composition above ambient temperature but preferably to less than 100°C.

The invention is illustrated by the following non-limiting examples. Example 1

A cleaning composition was formulated by admixing the following component.

Reodourant 0.30

This formulation is designated as 'Invention' in the Tables below.

The composition was used in a converted Spencer dry-cleaning (Model 113) with overnight distillation (not used). The cage diameter was 0.91 metres (3 feet). The following conditions were employed.

Washing Time 6.5 minutes

Drying Time 27 minutes

Solvent Temperature 35-40°C

Spin Time 1 minute

Ambient Temperature 18-22 C

Hot Air in Starts at 40°C

Hot Air out 33°C

Cage Temperature Up to 108°C Maximum The composition was tested on a light fawn 65% polyester/35% viscose fabric which had various stains applied thereto. The results were compared with those obtained using perchloroethylene (standard dry-cleaning solvent).

The results were as shown in the following Table. In the Table, the designation 'Totally' indicates that the stain was totally removed. Similarly 'Partially' indicates partial removal, 'Trace' indicates a trace was removed, 'Almost Totally' indicates almost total removal of the stain, and 'Not' indicates that the stain was not removed.

It can be seen from the above that, for many stains, the cleaning properties of the composition of the invention were more effective than those of the perchloroethylene.

Claims

1. An aqueous based cleaning composition comprising, in addition to a major part of water, a surface active agent, a base and an organic acid, or a salt of a base and an organic acid, and a dispersed phase of a hydrocarbon.

2. A composition as claimed in claim 1 wherein the hydrocarbon is a terpene.

3. A composition as claimed in claim 3 wherein the terpene comprises 4-isopropenyl-l-methylcyclohexene.

4. A composition as claimed in claim 3 wherein the terpene is provided by D'limonene.

5. A composition as claimed in any one of claims 1 to 4 wherein the hydrocarbon is present in an amount less than 5% by weight of the composition.

6. A composition as claimed in any one of claims 1 to 5 comprising an organic acid and a base.

7. A composition as claimed in claim 6 wherein the acid is a water soluble carboxylic acid having 6 or less carbon atoms.

8. A composition as claimed in claim 7 wherein the acid is acetic acid or formic acid.

9. A composition as claimed in any one of claims 6 to 8 wherein the acid is present in the composition in an amount less than 5% by weight.

10. A composition as claimed in any one of claims 6 to 9 wherein the base is ammonia.

11. A composition as claimed in any one of claims 6 to 10 wherein the amount of the base is less than 5% by weight.

12. A composition as claimed in any one of claims 1 to 11 wherein the surface active agent comprises a long chain sulphonic acid or salt thereof.

13. A composition as claimed in claim 12 wherein the surface active agent comprises a dodecyl benzene sulphonate.

14. A composition as claimed in any one of claims 1 to 13 wherein the amount of surface active agent is less than 5% by weight.

15. A composition as claimed in claim 1 comprising a monocarboxylic acid having less than 6 carbon atoms in any amount less than 2%, a base in an amount less than 2%, a surface active agent in an amount less than 2%, a terpene in an amount less than 2%, optional incidental ingredients, and a balance of water.

16. A process for the preparation of the cleaning composition as claimed in claim 1, the process comprising admixing a major proportion of water with minor proportions of a surface active agent, a base and an organic acid, or a salt of a base and an organic acid, and a hydrocarbon.

17. A method of cleaning an article comprising treating the article with a cleaning composition according to any one of claims 1 to 15.

18. A method as claimed in claim 17 wherein the article is a textile article.

19. A method as claimed in claim 18 wherein ultrasonic waves are directed at the textile article during the cleaning operation.

20. A method as claimed in claim 17 for cleaning leather.

21. A method as claimed in claim 17 for scouring wool.

22. A method as claimed in claim 17 for degreasing metal.

23. A method of cleaning a textile article, the method comprising arranging the textile article in a container which contains a cleaning compositions as claimed in any one of claims 1 to 15 and using ultrasonic waves to clean said article in said container.

24. A cleaning apparatus comprising a treatment fluid container in which a textile article to be cleaned may be immersed and ultrasonic cleaning means arranged to direct ultrasonic waves at said textile article when in said container.

25. Apparatus as claimed in claim 24 including holding means for a textile article.

26. Apparatus as claimed in claim 25 comprising movement means for moving a textile article held by said holding means first position in which it is not arranged within said container to a second position in which it is arranged within said container.

27. Apparatus as claimed in claim 25 or 26 including a plurality of holding means and/or movement means arranged to be selectively positioned adjacent said container so that a selected article to be cleaned may be arranged in said container.

28. Apparatus as claimed in claim 27 wherein said plurality of holding means and/or movement means are provided on a conveyor system, for example an endless conveyor.