SUMMARY OF THE INVENTION

The present invention relates to a method for removing silicone fluids or compositions containing silicone fluids from a surface. More specifically, the invention relates to a method fr removing silicone fluids from a surface by means of ap_ --ying to the surface a monosaccha- ride ester or a composition comprising a monosaccharide ester.

BACKGROUND OF THE INVENTION

Silicone fluids are widely used today both industrially and domestically and an immense number of industrial pro¬ ducts comprises silicone fluids.

One of the great disadvantages of silicone fluids is that, once applied to a surface, they are extremely dif¬ ficult to remove. Further, they have a tendency to creep, i.e. to migrate and spreaα over adjacent surfaces. For instance, it is a common experience that applications of silicone fluid as e.g. a lubricant in one corner of a room soon leads to occurrence of silicone film all over the surfaces of said room, e.g. floor, walls, furniture.

Methods known in the art for removing silicone fluids by chemical means are few and mostly based on hydrolysis of the silicone, i.e. relatively harsh methods.

In Noll, Walter: "Chemie und Technologie er Silicone" , Verlag Chemie GmbH, 2 . ed . , 196Q, page 512 , is recommen¬ ded acid hydrolysis at elevated temperature combined with solvent based detergent solutions.

EP 0 199 227 Bl discloses a process for removing sili-

cones from fibres, yarns or sheetlike textile material wherein agueous solutions of surface-active eguilibration catalysts which are capable of reversibly breaking sil- oxane bonds, e.g. organic esters of sulfuric acid and phosphoric acid and organic ammonium compounds, are used at elevated temperatures and high or low extremes of pH. The active substances applied in the process are environ¬ mentally undesirable.

GB Patent Specification 1.267.509 discloses a composition for removing silicone-containing materials from a glass surface, e.g. an automobile wind screen, which contains as the active substances eerie oxide and an organic det¬ ergent or surfactant. The disclosed compositions are ex- pensive in use.

European Patent Application EP 0 437 216 A2 discloses a silicone-dissolving agent comprising one or more mono- esters of a long chained branched carboxylic acid with a long chained branched alcohol. The use of such esters are undesirable from an environmental point of view since it is well known that long chained branched compounds are slowly biodegradable.

CS Patent 264 707 Bl disloses the use of strong brine

(20-50 w/w% NaCl in water) for removal of mold releasing silicone fluids from the surface of thermoplastics in order to enable painting of the surface.

Finally, it should be mentioned that certain solvents like trichloroethylene are capable of dissolving silicone fluids but these solvents have well-known adverse effects on the environment or constitute serious hazards for the personnel employing them.

Thus, even if a number of methods are known for removal of silicone fluids or films from surfaces, none are

broadly applicable and all of them have disadvantages either in relation to danger to the personnel, danger to the environment, undesirable influence on the surface to be treated or expensive in use.

BRIEF DESCRIPTION OF THE INVENTION

It has surprisingly been found that certain mono- or di- saccharide monoesters have the capability of easy and ef- ficient removal of silicone fluids or compositions con¬ taining silicone fluids from a variety of surfaces.

These esters may be applied in an aqueous solution, pre¬ ferably in a concentration of 0.001 - 10%, more preferab- ly in a concentration of 0.005 - 8%, especially in a con¬ centration of 0.01 - 5%. The removal or cleaning effect may be obtained with or without mechanical treatment de¬ pending on the surface and the type of silicone fluid or silicone-containing composition to be removed.

For environmental reasons it is preferred to use mono- or disaccharide monoesters of straight chain fatty acids with chain lengths from C ₈ to C ₂₂ . Esters of the shorter fatty acids are preferred for certain types of silicone fluids.

There are several advantages of the method of the present invention such as simple and easy cleaning under mild conditions, often ambient temperature and a low consump- tion of the active compound, i.e. the monoester. Also, the active monoesters are non-irritating to skin and ey¬ es, and are non-toxic. Furthermore, they are very quickly biodegraded and exhibit low aquatoxicity.

A further advantage which is due to the efficiency, low price and non-toxic and non-irritant properties of the esters applied in the method of the invention is that a

range of new applications for silicone fluids become pos¬ sible, i.e. applications which hitherto have been imposs¬ ible because of the resistance of the silicone fluid to removal. Examples of new applications are as mold release agents, metal working fluids, or for vehicle wash. Thus, all applications where a substantially complete removal of silicone is necessary after it has performed its func¬ tion are now possible due to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a method of substan¬ tially removing a silicone fluid or a silicone-containing composition from a surface which method comprises the steps of

a) applying to the surface an effective amount of a monoester compound of the general formula I

R-COO-X-OR ¹ (I)

wherein

X represents a mono- or disaccharide moiety carrying the group -OR ¹ at the anomeric carbon atom and carrying the group R-COO- at a primary hydroxy group;

R ¹ represents hydrogen, alkyl having 1 - 6 carbon atoms or one of the following groups

H3 CH3 0

\ / II

C C

/ \ / \

wherein Y represents methylene or ethylene; and

R represents straight or branched alkyl, alkenyl, alkadi¬ enyl or alkatrienyl having 4 - 24 carbon atoms optionally substituted with hydroxy; or mixtures thereof; and

b) optionally subjecting the surface to a mechanical treatment; and

c) removing the silicone fluid and the monoester com- pound(s) from the surface.

Conveniently, the steps of the method of the invention are consecutive steps.

Silicones are polyorganosiloxanes having a structure si¬ milar to that of organically modified quartz and a back¬ bone of alternating silicon and oxygen atoms. The back¬ bone can be modified in various ways through the incor¬ poration of carbon-based side groups such as methyl. Di- methyl-based silicones may be fluid, resinous or elasto- meric in nature depending on the molecular weight and the configuration of the molecule. Silicone fluids are also known as silicone oils or uncured silicones.

Silicone fluids are linear polymers having a number of silicon atoms in the chain from 2 to more than 1000 cor¬ responding to viscosities in the range of 0.65 to 2,000,000 mm ² /s (1 mm ² /s = 1 cS) . Branched polymers having the same viscosities may also be classified as silicone fluids; this is also applicable for polyorganocyclosil- oxanes which sometimes are referred to as volatile sili¬ cones. Each silicon atom is linked to the next via an in¬ termediate oxygen atom. The free valencies of the silicon atoms are saturated with organic groups, primarily methyl groups, but occasionally also with phenyl, vinyl or amino groups.

Thus, silicone fluids can be modified by incorporating reactive groups such as amino into the molecules as a means of attaching other organic groups, e.g. polygly- cols, or they can be combined with various solid materi¬ als such as silica aerogels and xerogels and hydrophobic silicas of various types, or linear polymers and cyclo- polymers can be combined. The resulting silicone copoly- mer fluids may have properties which are remarkable dif¬ ferent from the properties of the original fluids.

Examples of silicone fluids are polydimethyl siloxanes and copolymers thereof with polyalkyleneoxide; polydimet¬ hyl cyclosiloxanes, e.g. the tetramer and pentamer there¬ of, and mixtures thereof with e.g. polydimethyl siloxa- nes; polymethylphenylsiloxanes; trimethyl polysiloxanes; and stearoxy trimethyl silane wax.

Silicone fluids are transparent, tasteless and odourless liquids which are physiologically compatible, and their viscosity remains virtually constant over a wide range of temperatures. The silicone fluids are highly stable in the temperature range of about -60°C to about 300°C, they are pourable at low temperatures and have excellent di¬ electric properties and low surface tension.

Furthermore,silicone fluids have very desirable pro¬ perties such as water repellency, lubricity, low volati¬ lity and good shear stability, i.e. they display a high degree of chemical inertness and resistance to weather- ing.

The advantageous properties of silicone fluids make them extremely useful substances which may form the basis of emulsions, greases, adhesives, sealants, coatings and chemical specialties.

Thus, silicone fluids are useful in a variety of applica-

tions, e.g. as plastic additives, hydraulic fluids, vi¬ bration damping liquids, antifoamers, water repellent agents, impregnating agents, release agents, particle and fiber treatments, cosmetic additives, polishes, lubri- cants, surfactants and heat-transfer media.

In the present specification and claims, the term "sili¬ cone fluid" denotes a linear or branched polyorganosi- loxane compound, a polyorganocyclosiloxane compound or a copolymer thereof having a viscosity in the range of about 0.65 to 2,000,000 mm ² /s, preferably in the range of about 0.65 to 150 mm ² /s or the range of about 150 to 10,000 mm ² /s or in the range of about 10,000 to 1,000,000 mm ² /s, especially in the range of about 10 to 150 mm ² /s or the range of about 150 to 10,000 mm ² /s or the range of 10,000 to 700,000 mm ² /s, in which the free valencies of the silicon atoms are fully or partly saturated with met¬ hyl groups. In case of partly saturation with methyl groups, the remaining free valencies are saturated with groups selected among amino, phenyl and vinyl groups.

The term "silicone-containing composition" as used herein relates to a composition comprising a silicone fluid.

The term "surface" as used herein relates to any surface which may be subjected to treatment with a silicone fluid or a silicone-containing composition. Examples of surfac¬ es may be any hard surface such as metal, plastics, rub¬ ber, board, glass, wood, paper, concrete, rock, marble, gypsum and ceramic materials which optionally are coated, e.g with paint, enamel etc.; or any soft surface such as fibres of any kind (yarns, textiles, vegetable fibres, rock wool, hair etc.), skin (human or animal), and nails.

It is to be understood that by using the method of the present invention, a silicone fluid or a silicone-con¬ taining composition may be removed completely or may be

substatially removed, i.e. that the cleaned surface gives a clean impression by visual inspection and/or may be subjected to an assay showing a substantial removal of the silicone, e.g. preferably a removal of silicone of at least 70%, more preferably at least 85%, even more pre¬ ferably at least 95%, especially at least 98%, as com¬ pared to the amount of silicone fluid or silicone-con¬ taining composition present on the surface prior to applying the method of the invention.

In a preferred embodiment of the method of the invention is used a compound of formula I wherein X represents a monosaccharide moiety carrying the group -OR ¹ at the anomeric carbon atom and carrying the group R-COO- at a primary hydroxy group;

R ¹ represents alkyl with 2 - 6 carbon atoms or one of the following groups

H3C CH3 0

\ / II

C C

/ \ / \

wherein

Y represents methylene or ethylene; and R represents alkyl with 4 - 24 carbon atoms.

In all monosaccharides - apart from fructose - in formula I, the group designated -OR ¹ is connected to the terminal anomeric carbon atom.

The parent monosaccharide as well as the compounds of formula I may be in the α- or β-form. Mixtures of com¬ pounds in - or β-forms, respectively, may also be appli¬ ed in the method according to the present invention.

Preferably R ¹ is hydrogen or a linear or branched alkyl group, preferably an unsubstituted alkyl group. Preferab¬ ly, the group R ¹ contains 1, 2, 3 or 4 carbon atoms. Examples of specific, preferred groups R ¹ are methyl, et- hyl, propyl, isopropyl and butyl, most preferred ethyl and isopropyl.

X is a mono- or disaccharide moiety consisting of one he- xose or pentose unit. Preferred mono- or disaccharides corresponding to the moiety X are glucose, fructose, ri- bose, annose, galactose, ahalose and sucrose, the most preferred monosaccharides being glucose, sucrose and ga¬ lactose.

Preferred fatty acids corresponding to the moiety

R-COO- in formula I are saturated and unsaturated fatty acids, preferably containing 6 - 22 carbon atoms, more preferably containing 8 - 22 carbon atoms. Examples of such preferred fatty acids are hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, dode- canoic acid, tetradecanoic acid, hexadecanoic acid, oc- tadecanoic acid, eicosanoic acid, docosanoic acid, cis-9- octadecenoic acid, cis,cis-9,12-octadecadienoic acid, cis,cis,cis-9,12,15-octadecatrienoic acid and 12-hydroxy- 9-octadecenoic acid.

The selection of the optimal chain length of the fatty acid moiety depends on the surface to be cleaned as well as on the type of silicone fluid to be removed and may be determined by routine experimentation of a person skilled in the art.

In another preferred embodiment of the method of the in¬ vention is used a compound of formula I selected among the following compounds: ethyl 6-0-hexanoylglucoside, ethyl 6-0-heptanoylglucosi de, ethyl 6-0-octanoylglucoside, ethyl 6-O-nonanoylgluco

side, ethyl 6-O-decanoylglucoside, ethyl 6-0-dodecanoyl glucoside, ethyl 6-O-tetradecanoylglucoside, ethyl 6-0- hexadecanoylglucoside, ethyl 6-O-octadecanoylglucoside, ethyl 6-O-eicosanoylglucoside, ethyl 6-O-docosanoylgluco side, ethyl 6-0-cis-9-octadecenoylglucoside, ethyl 6-0- cis,cis-9,12-octadecadienoylglucoside, ethyl 6-0-cis,- cis,cis-9,12,15-octadecatrienoylglucoside, isopropyl 6-0- hexanoylglucoside, isopropyl 6-0-heptanoylglucoside, iso¬ propyl 6-O-octanoylglucoside, isopropyl 6-0-nonanoylglu- coside, isopropyl 6-0-decanoylglucoside, isopropyl 6-0- dodecanoylglucoside, isopropyl 6-0-tetradecanoylglucosi- de, isopropyl 6-O-hexadecanoylglucoside, isopropyl 6-0- octadecanoylglucoside, isopropyl 6-0-eicosanoylglucoside, isopropyl 6-0-docosanoylglucoside, isopropyl 6-0-cis-9- octadecenoylglucoside, isopropyl 6-0-cis,cis-9,12-octade cadienoylglucoside, isopropyl 6-0-cis,cis,cis-9,12,15- octadecatrienoylglucoside, propyl 6-0-hexanoylglucoside, propyl 6-0-heptanoylglucoside, propyl 6-0-octanoylgluco- side, propyl 6-0-nonanoylglucoside, propyl 6-0-decanoyl- glucoside, propyl 6-0-dodecanoylglucoside, propyl 6-0- tetradecanoylglucoside, propyl 6-0-hexadecanoylglucoside, propyl 6-0-octadecanoylglucoside, propyl 6-0-eicosanoyl¬ glucoside, propyl 6-0-docosanoylglucoside, propyl 6-0- cis-9-octadecenoylglucoside, propyl 6-0-cis,cis-9,12-oc tadecadienoylglucoside, propyl 6-0-cis,cis,cis-

9,12,15—octadecatrienoylglucoside, butyl 6-0-hexanoylglu¬ coside, butyl 6-0-heptanoylglucoside, butyl 6-0-octanoyl- glucoside, butyl 6-0-nonanoylglucoside, butyl 6-0-decano¬ ylglucoside, butyl 6-0-dodecanoylglucoside, butyl 6-0- tetradecanoyl-glucoside, butyl 6-0-hexadecanoylglucoside, butyl 6-0-octadecanoylglucoside, butyl 6-0-eicosanoyl¬ glucoside, butyl 6-0-docosanoylglucoside, butyl 6-0-cis- 9-octadecenoylglucoside, butyl 6-0-cis,cis-9,12-octa-de- cadienoylglucoside or butyl 6-0-cis,cis,cis-9,12,15- octadecatrienoylglucoside.

The monoesters used in the method according to the pres-

ent invention can be prepared as described in US Patent 5,191,071 or by conventional methods of preparation. US 5,191,071 discloses that the monoesters of the general formula I may be prepared by enzymatic syntheses of sugar esters in very high yields by using as substrates for the enzymatic esterification a carbohydrate carrying an alkyl group with 2 - 6 carbon atoms, phenyl or alkyl phenyl at the hydroxy group at the terminal anomeric carbon atom and a free fatty acid or an ester thereof as the ether substrate for the reaction. The products of the reaction are sugar esters carrying an alkyl group at the hydroxy group at the anomeric carbon atom. Using this process it is possible to prepare a preparation containing more than 80%, preferably more than 90%, even more preferred more than 95%, of a compound of formula I. The enzymes which can be applied by the process are enzymes capable of forming ester linkages. This group of enzymes comprises hydrolases, such as esterases, and lipases. The enzymes applied by the process may be used in a soluble state or the enzymes may be immobilised, if desired. Also, the enzymes may be modified by chemical or genetic methods in order to optimise their reactivity in regard to a speci¬ fic reaction of interest. Examples of specific enzymes which may be used by the process are porcine pancreatic lipase and microbial lipases obtained, e.g. from strains of Aspercfillus. Rhizopus. Pseudo onas. Enterobacterium. Chromobacterium. Geotricium. Penicillium. Mucor. Candida, and Humicula. Examples of preferred strains are Mucor Miehei, Candida antarctica. DSM 3855, DSM 3908 and DSM (deposited at Deutsche Sammlung von Mikroorganismen according to the Budapest Treaty at 29 September 1986, 8 December 1986 and 8 December 1986, respectively) Pseudomonas cepacia. DSM 3959 (deposited on 30 January 1987) , and Humicola lanuqinosa. DSM 3819 and DSM 4109 (deposited on 13 August 1986 and 4 May 1987, respective¬ ly) . Further lipases are obtainable from Humicola brevispora. brevis var. ther oidea and insolens which

were deposited at DSM under the Nos. 4110, 4111 and 1800, respectively, on 4 May 1987, 4 May 1987 and 1 October 1981, respectively. Additional lipases are obtainable from the following strains, which are freely available to the public from Centralbureau voor Schimmelculturen

(CBS) , American Type Culture Collection (ATCC) , Agricul¬ tural Research Culture Collection (NRRL) and Institute of Fermentation, Osaka (IFO) under the indicated deposit numbers: Candida antarctica: CBS 5955, ATCC 34888, NRRL Y-8295, CBS 6678, ATCC 28323, CBS 6821 and NRRL Y-7954; Candida tsukubaensis: CBS 6389, ATCC 24555 and NRRL Y- 7792; Candida auriculariae: CBS 6379, ATCC 24121 and IFO 1580; Candida humicola: CBS 571, ATCC 14438, IFO 0760, CBS 2041, ATCC 9949, NRRL Y-1266, IFO 0753 and IFO 1527 and Candida foliorum: CBS 5234 and ATCC 18820.

The process may be carried out simply by mixing a glycoside of the general formula HO - X - OR ¹ , where X and R ¹ each is as defined above, with an acid or an ester thereof of the general formula R-COOR ² , where R ² repre¬ sents hydrogen or lower alkyl, in the presence of the enzyme and, optionally, the reaction may be carried out in a solvent in which the enzyme exhibits the desired activity. Preferably, no solvent is added. If an organic solvent is used, it should have no deleterious effect on the enzyme. Examples of such solvents are ketones, hydro¬ carbons and ethers. Preferred solvents are pentan, hexan, heptan and 2-butanone. Preferably, the reaction medium is non-aqueous or contains only the approximate amount of water which is needed to ensure a good reactivity and life-time of the applied enzyme. Conveniently, the reac¬ tion temperature is in the range of about 20 - 100°C, preferably about 30 - 80°C. Preferably, the reaction is performed at a low pressure, preferably below about 0.05 bar.

The monoesters used in the method according to the inven-

tion may be used in dilute aqueous solutions alone, i.e. as the only active ingredient, and without builders or other ingredients. Under certain conditions it may be de¬ sirable to formulate the monoesters with other detergent ingredients known in the art, for instance to aid in par¬ ticle removal or to prevent particle redeposition on the surface to be cleaned.

In a preferred embodiment of the present invention, the monoesters are applied in an aqueous solution, preferably in a concentration of between about 100 ppm and about 100,000 ppm, more preferably in a concentration of between about 500 ppm and about 80,000 ppm, especially in a concentration of between about 1000 ppm and about 50,000 ppm.

In another aspect, the present invention relates to a cleaning composition comprising a monoester of the for- ro-.ila I capable of substantially removing silicone fluids or silicone elastomers or silicone-containing composi¬ tions from a surface. Such a cleaning composition may comprise an efficient amount of a monoester of the for¬ mula I and water and optionally one or more builders, surfactants and/or additives. The pH of the cleaning com- position is preferably neutral or near-neutral such as below 8, whereby the conventional hazards of alkaline or highly alkaline cleaning composition may be avoided.

A cleaning composition comprising a compound of formula I may be in any convenient form, such as a powder or a li¬ quid.

Liquid and powder cleaning compositions may be formulated in analogy with "Frame formulations for liquid/powder heavy-duty detergents" (J. Falbe: Surfactants in Consumer Products. Theory, Technology and Application, Springer- Verlag 1987) by replacing all or part (e.g. 50%) of the

non-ionic surfactant with a compound of formula I. Thus, liquid cleaning compositions may in addition to the com¬ pound of formula I comprise anionic surfactants, non-io¬ nic surfactants, cationic surfactants, amphoteric surfac- tants, suds controlling agents, foaming boosters, enzy¬ mes, builders, formulation aids, chelating agents, anti- corrosion agents, optical brighteners, stabilizers, fab¬ ric softeners, fragrances, dyestuffs and water.

Similarly, powder cleaning compositions may comprise an¬ ionic surfactants, non-ionic surfactants, cationic sur¬ factants, amphoteric surfactants, suds controlling agents, foaming boosters, chelating agents, ion exchan¬ gers, alkalis, cobuilders, bleaching agents, bleach ac- tivators, bleach stabilizers, fabric softeners, antirede- position agents, enzymes, optical brighteners, anticorro- sion agents, fragrances, dyestuffs and blueing agents, formulation aids, fillers and water.

It should be noted that the cleaning composition of the invention may be useful at any pH and any temperature usually applied in cleaning processes. Accordingly, the present method may preferably be applied at any tempera¬ ture between about 5°C and about 100°C, more preferably at a temperature below about 70°C. For a substantial removal of certain types of silicone fluids or silicone- containing compositions from certain surfaces, it may be advantageous to apply the method at a temperature above ambient temperature. The determination of the optimum or near optimum temperature is a matter of routine experi¬ mentation for the skilled person. Also, the present method may be applied at any pH. However, it may be con¬ venient to apply the method at neutral or near-neutral pH for safety and environmental reasons.

A problem regularly seen in the automobile repair busi¬ ness is repainting a car which has been treated with a

silicone fluid based lacquer sealant. The new layer of paint applied will not spread evenly but leaves small holes due to the silicone. As a result four to six subse¬ quent painting operations have to be performed before an intact surface is obtained. Obviously, the result is not acceptable.

A common problem is experienced in the building business where silicone based joint fillers are widely applied. Any accidental contamination of surfaces adjacent to where the filler is applied requires, if not removed im¬ mediately, tediously scraping with e.g. a knife and for¬ ceful rubbing with a wet cloth. Even then it is normally not possible to get the surface completely clean.

Also, spillages of silicone fluids requires extended scrubbing to remove and often it is simply not possible to clean the contaminated surface fully.

The present invention provides a method which is believed to solve problems of the nature stated above.

Thus, it is contemplated that the method of the invention is useful in the petrochemical industry, the agrochemical industry, the food industry, the detergent industry, the tyre industry, in the treatment of sewage, in the cosme¬ tics industry, the pharmaceuticals industry, the textile industry, the leather industry, the plastics industry, the metal industry, in construction, and in the surface and coating industry.

Furthermore, it is contemplated that the method of the invention is useful for removing silicone-containing hair care products, skin care products, deodorants, decorative cosmetics, oral hygiene products, softening products, water repellant products, defoaming products, adhesion promoting products, sewing-thread lubricants, laquer ad-

ditives, thermostable paints, functional coatings, anti- corrosion protection products, coil coating products, silicone alkyds, printing inks, plasticising additives, toners, fuser oils, release agents, pharmaceutical prod- ucts, welding additives, automobile polishes, furniture polishes; and/or for removing silicone fluids used in the preparation or manufacture of such products.

It is contemplated that the method of the present inven- tion may also prove useful for the removal of silicone elastomers or silicone resins (semi-cured or cured sili¬ cones) or compositions comprising such substances.

The invention is further described in the following exam- pies which are not intended to as in any way limiting the scope of the invention.

EXAMPLE 1

An object glass for use in a microscope was greased with conventional silicone-containing laboratory cockstopper grease whereafter it was placed in a laboratory ultra¬ sonic cleaning bath filled with a 0.5% aqueous solution of ethyl-6-0-decanoylglucoside.

The ultrasound was turned on for 5 minutes during which period the layer of silicone concentrated into droplets which finally left the glass slide and rose to the sur¬ face of the bath.

EXAMPLE 2

A spherical laboratory flask for vacuum distillation which was soiled with silicone fluid (supplied by Dow- Corning, brand name DC 200, having a viscosity of 100 mm ² /s) used for heating the flask was rubbed with a cloth soaked in a 10% aqueous solution of ethyl-6-0-decanoyl-

glucoside.

The flask was rinsed in tap water and finally wiped dry with a clean cloth. As a result the flask surface became completely clean.

A similar procedure was used to clean the vinyl floor where the same silicone fluid was spilled. Again, the floor became totally free of silicone as evaluated by visual inspection.

EXAMPLE 3

Accidental spots, 4 days old, of silicone joint filler used for stabilizing glass in metal frames for revolving doors was efficiently and easily removed from the glass by spraying the glass with a 0.5% solution of ethyl-6-0- decanoylglucoside in tap water, followed by wiping with a clean cloth.

EXAMPLE 4

Silicone joint filler which had contaminated a wooden kitchen table and where the stains were several months old were easily removed by rubbing with a cloth soaked in a 10% solution of ethyl 6-O-coconut fatty acyl glucoside followed by wiping with a clean moist cloth.

EXAMPLE 5

A washing machine which is used for washing flasks for insulin was sometimes used for washing ampoules which are siliconized on the inside. This leaves silicone on the washing machine's inner surfaces which is transferred to the non-siliconized flasks in the following many wash cycles. As a consequence the labels on the flasks fall off. Normally, it takes 5 to 6 washing cycles before the

silicone oil is removed.

The silicone fluid used for siliconizing ampoules was a Wacker Silicone Fluid Emulsion E2 (35% dispersion of a non-reactive medium-viscosity (2000 - 7500 mPa/s) dimet¬ hyl polysiloxane in water) , supplied by Wacker-Chemie GmbH, Munich, Germany. It was applied on the ampoules at a solids content of 1%.

In several tests it was shown that a single washing cycle with a 0.2% solution of ethyl-6-0-decanoylglucoside com¬ pletely cleaned the machine.

EXAMPLE 6

Removal of silicone oil from a metal surface

The following experiments were carried out in order to demonstrate the cleaning effect of the method of the invention.

Materials and methods:

- 15 stainless steel discs (type 18/8-Cr/Ni) , mat, each measuring 60 mm in diameter and having a thickness of 3 mm were selected for equal appearance and perform¬ ance.

- Silicone fluid: PDMS (Dimethyl silane, obtained from Wacker Chemie, type Wacker AK350, 350 cP) .

- Pre-cleaning agent: Deconex (Borer Chemie) . - De ineralised water.

- Chroma Meter (Minolta CR300, measuring head 8 mm) .

15 discs were cleaned in Deconex 20% at room temperature overnight. The discs were rinsed with hot tap water fol- lowed by rinsing with demineralised water and drying with a clean towel. The discs were left to equilibrate for about 60 minutes. Each disc was weighed and the

reflectance was measured with a Chroma Meter as an aver¬ age of 3 measurements. The discs were soiled by applying 6 drops of silicone fluid in the middle of the horizon¬ tally placed discs which were allowed to migrate to a diameter of about 35-40 mm within about 1 hour. The soiled discs were weighed and the reflectance was measured (average of 3 measurements) . Five 1000 ml beakers were each filled with 800 ml cleaning or deter¬ gent solution to be tested and placed on a magnetic stirrer at room temperature. 3 discs were immersed in each beaker and kept under vigorous circulation for 5 minutes. The discs were removed from the beakers, dried and allowed to equilibrate for 1 hour, followed by weigh¬ ing and measurement of reflectance (average of 3 measure- ments) .

The following compounds were tested:

A: Ethyl 6-0-decanoylglucoside B: Ethyl 6-0-dodecanoylglucoside

C: Ethyl 6-0-coconut fatty acyl glucoside

D: C ₁₂ . ₁₄ alkylpolyglycoside (DP 1,4) sold under the trade name "Plantaren 600" (manufactured by Henkel KGaA, Dϋsseldorf, Germany) . E: C _g . ₁₀ alkylpolyglycoside (DP 1,6) sold under the trade name "APG 225 UP" (manufactured by Henkel KGaA, Dϋsseldorf, Germany) . F: C, ₆ -alkylether ethoxylate (C ₆ E0 ₂ ) [AEO] sold under the trade name "BRIJ52" (manufactured by ICI Chemicals and Polymers, Ltd, Middlesborough, Cleveland, U.S.A.). G: Conventional laboratory cleaning agent sold under the trade name "RBS 35" (sold by Bie & Berntsen, Denmark, Catalogue No. 27000; manufactured by Carl Roth GmbH + Co. , Karlsruhe, Germany).

Cleaning compositions each containing one of the com-

pounds to be tested were prepared by heating the ethyl glycoside in question to 60°C, mixing the ester with boiling demineralised water and performing the final dilution with cold demineralised water.

Compounds D, E, F and G are comparison compounds. Each compound was tested in various concentrations, i.e. con¬ centration (w/w%) of active compound in the cleaning or detergent solution in order to determine the minimum con¬ centration giving optimum cleaning effect.

The cleaning effect is expressed in terms of the differ¬ ence in reflectance measurements of soiled and cleaned discs, since the amount of silicone present on the metal discs after applying the method of the invention was too low to be determined by weighing the discs.

The cleaning effect is expressed as "% recovery of light reflection".

The results are shown in Table 1.

TABLE 1

Compound % Recovery Min. dosage for pH of light optimum cleaning reflection

A >90 0.05 w/w% 5-7

B >90 0.01 w/w% 5-7

C -60 0.1 w/w% 5-7

D >90 0.005 w/w% -6

E >90 0.1 w/w% 9-10

F no effect - -6

G >80 >3-5 W/W% 11-12

From the data it can be concluded that compounds A and B (ethyl 6-0-decanoylglucoside and ethyl 6-O-dodecanoyl- glucoside, respectively) have the same good cleaning effect as the known, conventional cleaning compositions D and E (Plantaren and APG225) but may either be more effective (lower minimum dosage required for obtaining same good effect) , more economical or more environmental- friendly.

EXAMPLE 7

Removal of silicone oil from glass and plastic surfaces

The following experiments were carried out in order to demonstrate the cleaning effect of the method of the invention on glass and plastic surfaces.

Materials and methods:

The materials were as described in example 6 except for:

- 15 float glass discs each measuring 60 mm in diameter and having a thickness of 4 mm were selected for equal appearance and performance.

- 15 PPMMA acrylic discs each measuring 60 mm in diam¬ eter and having a thickness of 4 mm were selected for equal appearance and performance.

The method was as described in example 6 except for:

1. The discs were cleaned in Deconex 20% before soiling for 10 minutes.

2. Since the glass and acrylic discs were transparent, the reflectance was measured with standard white paper as background.

The following compounds were tested:

B: Ethyl 6-O-dodecanoylglucoside

G: Conventional laboratory cleaning agent sold under the trade name "RBS 35" (sold by Bie & Berntsen, Denmark, Catalogue No. 27000; manufactured by Carl Roth GmbH + Co., Karlsruhe, Germany).

The cleaning effect is expressed as "% weight removal of silicone".

The results are shown in Table 2.

TABLE 2

Glass - Min. dosage for Acrylic plast Min. dosage

Compound % Removal optimum clean¬ % Removal for opt. clean¬ (weight) ing (glass) (weight) ing (acr. plast)

B 97 0. 5 w/w% 99 0 . 5 w/w%

G 99 5-10 w/w% 85 10 w/w%

From the data it can be concluded that compound B (ethyl 6-O-dodecanoylglucoside) has the same good cleaning effect on glass as the known, conventional cleaning com¬ position G (RBS 35) but is at least 10 times more effec¬ tive (lower minimum dosage required for obtaining same good effect) and, likewise, ethyl 6-0-dodecanoylglucoside has a better cleaning effect on acrylic plast than com¬ pound G (RBS 35) and is much more effective (at least 20 times) .