EP0450539A2 - Process for cleaning hydrophilic porous matrices - Google Patents
Process for cleaning hydrophilic porous matrices Download PDFInfo
- Publication number
- EP0450539A2 EP0450539A2 EP91105096A EP91105096A EP0450539A2 EP 0450539 A2 EP0450539 A2 EP 0450539A2 EP 91105096 A EP91105096 A EP 91105096A EP 91105096 A EP91105096 A EP 91105096A EP 0450539 A2 EP0450539 A2 EP 0450539A2
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- EP
- European Patent Office
- Prior art keywords
- process according
- water
- surfactant
- heterogeneous system
- compress
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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- 238000000034 method Methods 0.000 title claims abstract description 18
- 238000004140 cleaning Methods 0.000 title claims abstract description 7
- 239000000126 substance Substances 0.000 claims abstract description 18
- 239000012736 aqueous medium Substances 0.000 claims abstract description 5
- 239000008151 electrolyte solution Substances 0.000 claims abstract description 3
- 229940021013 electrolyte solution Drugs 0.000 claims abstract description 3
- 239000004530 micro-emulsion Substances 0.000 claims description 19
- 230000002209 hydrophobic effect Effects 0.000 claims description 18
- 239000004094 surface-active agent Substances 0.000 claims description 18
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 18
- 239000001913 cellulose Substances 0.000 claims description 16
- 229920002678 cellulose Polymers 0.000 claims description 16
- 239000012535 impurity Substances 0.000 claims description 14
- SNRUBQQJIBEYMU-UHFFFAOYSA-N dodecane Chemical compound CCCCCCCCCCCC SNRUBQQJIBEYMU-UHFFFAOYSA-N 0.000 claims description 10
- 230000007928 solubilization Effects 0.000 claims description 9
- 238000005063 solubilization Methods 0.000 claims description 9
- AMQJEAYHLZJPGS-UHFFFAOYSA-N N-Pentanol Chemical compound CCCCCO AMQJEAYHLZJPGS-UHFFFAOYSA-N 0.000 claims description 8
- 239000000839 emulsion Substances 0.000 claims description 8
- 239000007788 liquid Substances 0.000 claims description 8
- 239000000693 micelle Substances 0.000 claims description 7
- DBMJMQXJHONAFJ-UHFFFAOYSA-M Sodium laurylsulphate Chemical compound [Na+].CCCCCCCCCCCCOS([O-])(=O)=O DBMJMQXJHONAFJ-UHFFFAOYSA-M 0.000 claims description 6
- 235000019333 sodium laurylsulphate Nutrition 0.000 claims description 6
- 239000006185 dispersion Substances 0.000 claims description 5
- 239000003995 emulsifying agent Substances 0.000 claims description 5
- 229920006395 saturated elastomer Polymers 0.000 claims description 5
- 125000000217 alkyl group Chemical group 0.000 claims description 4
- 230000001476 alcoholic effect Effects 0.000 claims description 2
- 239000004745 nonwoven fabric Substances 0.000 claims description 2
- 238000007789 sealing Methods 0.000 claims 1
- -1 alkyl-ammonium halides Chemical class 0.000 description 11
- 239000004698 Polyethylene Substances 0.000 description 6
- 239000012071 phase Substances 0.000 description 6
- 229920000573 polyethylene Polymers 0.000 description 6
- 239000000758 substrate Substances 0.000 description 4
- 239000000463 material Substances 0.000 description 3
- 150000001338 aliphatic hydrocarbons Chemical class 0.000 description 2
- 125000000129 anionic group Chemical group 0.000 description 2
- 239000007864 aqueous solution Substances 0.000 description 2
- 125000002091 cationic group Chemical group 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 238000001704 evaporation Methods 0.000 description 2
- BXWNKGSJHAJOGX-UHFFFAOYSA-N hexadecan-1-ol Chemical compound CCCCCCCCCCCCCCCCO BXWNKGSJHAJOGX-UHFFFAOYSA-N 0.000 description 2
- 239000002502 liposome Substances 0.000 description 2
- 239000007791 liquid phase Substances 0.000 description 2
- 239000003960 organic solvent Substances 0.000 description 2
- 239000002904 solvent Substances 0.000 description 2
- KILNVBDSWZSGLL-KXQOOQHDSA-N 1,2-dihexadecanoyl-sn-glycero-3-phosphocholine Chemical compound CCCCCCCCCCCCCCCC(=O)OC[C@H](COP([O-])(=O)OCC[N+](C)(C)C)OC(=O)CCCCCCCCCCCCCCC KILNVBDSWZSGLL-KXQOOQHDSA-N 0.000 description 1
- CPELXLSAUQHCOX-UHFFFAOYSA-M Bromide Chemical compound [Br-] CPELXLSAUQHCOX-UHFFFAOYSA-M 0.000 description 1
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 1
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 1
- 239000004743 Polypropylene Substances 0.000 description 1
- 239000004141 Sodium laurylsulphate Substances 0.000 description 1
- 230000002745 absorbent Effects 0.000 description 1
- 239000002250 absorbent Substances 0.000 description 1
- 238000004220 aggregation Methods 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- 150000001298 alcohols Chemical class 0.000 description 1
- 239000003945 anionic surfactant Substances 0.000 description 1
- 239000008346 aqueous phase Substances 0.000 description 1
- 150000004945 aromatic hydrocarbons Chemical class 0.000 description 1
- 125000004432 carbon atom Chemical group C* 0.000 description 1
- 239000003093 cationic surfactant Substances 0.000 description 1
- 229960000541 cetyl alcohol Drugs 0.000 description 1
- 239000008367 deionised water Substances 0.000 description 1
- 229910021641 deionized water Inorganic materials 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- LQZZUXJYWNFBMV-UHFFFAOYSA-N dodecan-1-ol Chemical compound CCCCCCCCCCCCO LQZZUXJYWNFBMV-UHFFFAOYSA-N 0.000 description 1
- DDXLVDQZPFLQMZ-UHFFFAOYSA-M dodecyl(trimethyl)azanium;chloride Chemical compound [Cl-].CCCCCCCCCCCC[N+](C)(C)C DDXLVDQZPFLQMZ-UHFFFAOYSA-M 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 229910052736 halogen Chemical class 0.000 description 1
- 150000002367 halogens Chemical class 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 235000012054 meals Nutrition 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- DULAEBAGAYVIDN-UHFFFAOYSA-N n-dodecyl-n-methyldodecan-1-amine;hydrochloride Chemical compound [Cl-].CCCCCCCCCCCC[NH+](C)CCCCCCCCCCCC DULAEBAGAYVIDN-UHFFFAOYSA-N 0.000 description 1
- 239000002736 nonionic surfactant Substances 0.000 description 1
- 239000011505 plaster Substances 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 229920003023 plastic Polymers 0.000 description 1
- 229920001155 polypropylene Polymers 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- GGHPAKFFUZUEKL-UHFFFAOYSA-M sodium;hexadecyl sulfate Chemical compound [Na+].CCCCCCCCCCCCCCCCOS([O-])(=O)=O GGHPAKFFUZUEKL-UHFFFAOYSA-M 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 230000003381 solubilizing effect Effects 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 238000009736 wetting Methods 0.000 description 1
- 239000002888 zwitterionic surfactant Substances 0.000 description 1
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
- C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
- C11D17/00—Detergent materials or soaps characterised by their shape or physical properties
- C11D17/0008—Detergent materials or soaps characterised by their shape or physical properties aqueous liquid non soap compositions
- C11D17/0017—Multi-phase liquid compositions
- C11D17/0021—Aqueous microemulsions
-
- C—CHEMISTRY; METALLURGY
- C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
- C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
- C11D2111/00—Cleaning compositions characterised by the objects to be cleaned; Cleaning compositions characterised by non-standard cleaning or washing processes
- C11D2111/10—Objects to be cleaned
- C11D2111/14—Hard surfaces
- C11D2111/24—Mineral surfaces, e.g. stones, frescoes, plasters, walls or concretes
Definitions
- the present invention relates to a process for cleaning hydrophilic porous matrices.
- the present invention relates to a process for removing hydrophobic impurities from wall surfaces or pictorial works of art etc., by means of circumscribed solubilization of said impurities.
- the complex and numerous operations which are used for the restoration of a work of art and in particular of frescos comprise also "cleaning" operations, i.e. the removal of impurities - for the most part solid impurities - which may be present and usually are distributed at random, said operations often being of particular importance.
- cleaning operations i.e. the removal of impurities - for the most part solid impurities - which may be present and usually are distributed at random, said operations often being of particular importance.
- hydrophobic impurities which are distributed in porous (and generally hydrophilic) matrices.
- the removal of hydrophobic impurities from generally hydrophilic porous matrices can be carried out, without the above drawbacks, by using dispersed heterogeneous systems composed of dispersions of a liquid in another liquid insoluble therein, stabilized by amphiphilic substances, or of molecular aggregates of said amphiphilic substances dispersed in an aqueous medium or in aqueous electrolyte solutions.
- amphiphilic substances whenever used in the present specification and in the claims, denotes those substances whose molecular structure contains both a hydrophilic portion and a hydrophobic portion; therefore, said substances are stable at the interface of the heterogeneous system and act as surfactants.
- heterogeneous systems utilized in the process of the present invention are preferably in the form of:
- amphiphilic substances are employed to stabilize the heterogeneous system. They can be emulsifiers or surfactants.
- Emulsions are composed of a continuous liquid phase and of a discontinuous liquid phase immiscible therewith, the latter being dispersed in the former by means of an emulsifier.
- emulsifier Common emulsion types are oil-in-water and water-in-oil; the term "oil” being used to denote any water-in-soluble fluid, such as, e.g., an aliphatic or aromatic hydrocarbon or a halogen derivative thereof.
- emulsifiers are distributed over the surface of the dispersed phase.
- suitable emulsifiers are cetyl alcohol and lauryl alcohol with sodium cetylsulphate or sodium laurylsulphate.
- mice denotes any molecular aggregate of about 50 to about 100 molecular units of an amphiphilic substance which spontaneously forms in aqueous media above a certain concentration which depends on the type of amphiphilic substance utilized. Said aggregates can exhibit different shapes such as spheric, cylindrical or disc-like.
- the amphiphilic substance can be a known surfactant which is arranged with the hydrophilic portion turned towards the water phase and the hydrophobic portion turned towards the molecular aggregate inside.
- the surfactants capable of forming micelles can be cationic, anionic, non-ionic or zwitterionic surfactants.
- Suitable surfactants are sodium alkylsulphates of formula: CH3-(CH2) n - 0 - SO3 ⁇ Na+ wherein n is an integer ranging from 6 to 30; and the alkyl-ammonium halides of formula: CH3(CH2) n - N+ (R)3 A ⁇ wherein n is an integer of from 6 to 30, R is an alkyl radical containing from 1 to 3 carbon atoms and A ⁇ is a halide ion such as bromide and chloride.
- Suitable surfactants of the non-ionic type are, e.g., poly-(oxyethylene) alcohols or poly(oxyethylene) alkylphenols.
- surfactants are sodium dodecylsulphate and dodecyl-trimethyl-ammonium chloride.
- amphiphilic substance exhibits a double alkyl chain, single-lamellar or multi-lamellar aggregation structures (which are called blisters or liposomes) are obtained.
- Preferred double alkyl chain surfactants are didodecyl-methyl-ammonium chloride of formula [ CH3(CH2)11 ]2 N+ (CH3)2 Cl ⁇ and dipalmitoyl phosphatidyl choline of formula
- Microemulsions are composed of two immiscible liquids such as water and oil and of a surfactant and a co-surfactant, both arranged at the interface of the two immiscible liquids.
- microemulsions are stable, homogeneous and optically transparent and form spontaneously.
- micelles and oil-in-water microemulsions are preferred in the cleaning process of the present invention.
- microemulsions have proved to be surprisingly effective.
- This system preferably consists of a microemulsion of an aliphatic hydrocarbon in water, stabilized with a surfactant of the non-ionic, anionic or cationic type and with a preferably alcoholic co-surfactant.
- microemulsion is a system composed of dodecane in water and containing sodium dodecylsulphate as surfactant and pentanol as co-surfactant.
- the hydrophilic phase of the dispersion is particularly suitable for the hydrophilic substrate onto which it has to act.
- solubilization areas in particular, in the micelles and in the blisters, the solubilization of the hydrophobic impurities occurs in molecular areas which are also hydrophobic while in the emulsions and microemulsions the solubilization occurs in areas substantially consisting of the hydrophobic oil phase dispersed in the hydrophilic matrix.
- All these systems act as solubilizers of the hydrophobic impurities, thus eliminating the drawbacks caused by the treatment of surfaces with organic solvents. Furthermore, all these systems are suitable for being applied onto hydrophilic substrates, such as those of wall surfaces and pictorial works in general, as they exhibit a continuous aqueous phase which secures the wetting of the hydrophilic matrices, and therefore their contact with the hydrophobic material, for a sufficiently long period of time.
- the cleaning process usually comprises the following steps carried out in the order given:
- the hydrophobic impurities After removal of the compresses the hydrophobic impurities have been solubilized or at any rate detached from the substrate and are therefore readily and spontaneously removable.
- the cellulose pulp can, for example, be of a type such as ARBOCEL® BC or mixtures thereof with ARBOCEL® BWW.
- the synthetic pulp can, for instance, be composed of polyethylene and/or polypropylene fibrils.
- any other inert and absorbent substrate can be utilized such as, for example, fossil meal, micronized silicas etc.
- the duplex paper usually consists of an inner plastic material sheet, such as polyethylene (which is brought into contact with the surface to be treated), and of an outer cellulose sheet.
- An alternative method of application comprises causing the heterogeneous system to continuously flow, at a controlled flowrate, from a proper container (tank) to the area of interest - previously subjected to a humidification treatment - through a suitable micropiping, and removing the heterogeneous system downstream after solubilization of the hydrophobic impurities has occurred.
- Said method permits a continuous renewal of the solubilizing agent.
- a microemulsion was prepared by dispersing 0.08% by volume of dodecane in an aqueous solution of 0.5 moles of sodium dodecylsulphate and 1 mole of pentanol. Dodecane was gradually added under stirring. The system, opalescent at the beginning, became suddenly limpid after a few hours and remained in this state when maintained at a temperature ranging from 15 to 35°C.
- the fresco surface to be cleaned containing splashes of wax (H) was first treated with a compress of cellulose pulp (type ARBOCEL BC 200®) impregnated with deionized water, in order to saturate the plaster surrounding the wax-coated area with humidity.
- a compress of cellulose pulp type ARBOCEL BC 200®
- deionized water in order to saturate the plaster surrounding the wax-coated area with humidity.
- the cellulose pulp compress was removed and replaced by a compress (A) composed of 70% of cellulose type ARBOCEL® BC 200 and 30% of cellulose pulp type ARBOCEL® BWW 40, impregnated with the water/sodium dodecyl sulphate/pentanol/dodecane microemulsion prepared as described above.
- Compress (A) was surrounded by a compress (B) of cellulose pulp type ARBOCEL® BC 300 impregnated with dionized water, and the whole was coated with Japanese paper and cellulose pulp impregnated with water (C).
- the microemulsion was made to flow in contact with the surface to be cleaned from a bottle (L) through a pipe equipped with a flow regulator (I), the cannula (E) of said pipe being in contact with the part to be cleaned through a perforation in compresses (B) and (C).
- Compresses (B) and (C) were covered with a duplex paper consisting of a polyethylene film (D) and of a cellulose paper sheet (F) in order to prevent the components of the microemulsion from evaporating.
- a duplex paper sheet (G) was arranged, which consisted of a polyethylene layer in contact with the fresco and of an outer layer of cellulose paper. In this manner the polyethylene layer isolated the picture while the paper absorbed the excess microemulsion, thereby preventing it from dropping onto the underlying picture surface.
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- Chemical & Material Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Wood Science & Technology (AREA)
- Organic Chemistry (AREA)
- Cleaning Implements For Floors, Carpets, Furniture, Walls, And The Like (AREA)
Abstract
Description
- The present invention relates to a process for cleaning hydrophilic porous matrices.
- More in particular, the present invention relates to a process for removing hydrophobic impurities from wall surfaces or pictorial works of art etc., by means of circumscribed solubilization of said impurities.
- The complex and numerous operations which are used for the restoration of a work of art and in particular of frescos comprise also "cleaning" operations, i.e. the removal of impurities - for the most part solid impurities - which may be present and usually are distributed at random, said operations often being of particular importance. Of particular interest is the removal of hydrophobic impurities, which are distributed in porous (and generally hydrophilic) matrices.
- In these cases, the most obvious operation would be the treatment with hydrophobic organic solvents capable of solubilizing the impurities. Generally, however, said treatment only has the effect of distributing said impurities over a greater surface or to convey them into the porous hydrophilic material which is typical of the surfaces considered.
- According to the present invention, the removal of hydrophobic impurities from generally hydrophilic porous matrices can be carried out, without the above drawbacks, by using dispersed heterogeneous systems composed of dispersions of a liquid in another liquid insoluble therein, stabilized by amphiphilic substances, or of molecular aggregates of said amphiphilic substances dispersed in an aqueous medium or in aqueous electrolyte solutions.
- The term "amphiphilic substances", whenever used in the present specification and in the claims, denotes those substances whose molecular structure contains both a hydrophilic portion and a hydrophobic portion; therefore, said substances are stable at the interface of the heterogeneous system and act as surfactants.
- The heterogeneous systems utilized in the process of the present invention are preferably in the form of:
- (a) emulsions, apparently heterogeneous, optically non-transparent and only kinetically stable;
- (b) micelles, i.e. aggregates of amphiphilic substances, surface-active in water;
- (c) blisters and/or liposomes, i.e. molecular aggregates consisting of structures composed of a double layer of amphiphilic molecules having an approximately spheric shape; or
- (d) microemulsions, apparently homogeneous, optically transparent and thermodynamically stable (in contrast to the above "real" emulsions).
- The amphiphilic substances are employed to stabilize the heterogeneous system. They can be emulsifiers or surfactants.
- Emulsions are composed of a continuous liquid phase and of a discontinuous liquid phase immiscible therewith, the latter being dispersed in the former by means of an emulsifier. Common emulsion types are oil-in-water and water-in-oil; the term "oil" being used to denote any water-in-soluble fluid, such as, e.g., an aliphatic or aromatic hydrocarbon or a halogen derivative thereof.
- These systems are generally cloudy, lactescent and thermodynamically unstable. The emulsifier is distributed over the surface of the dispersed phase. Examples of suitable emulsifiers are cetyl alcohol and lauryl alcohol with sodium cetylsulphate or sodium laurylsulphate.
- The term "micelles" denotes any molecular aggregate of about 50 to about 100 molecular units of an amphiphilic substance which spontaneously forms in aqueous media above a certain concentration which depends on the type of amphiphilic substance utilized. Said aggregates can exhibit different shapes such as spheric, cylindrical or disc-like.
- The amphiphilic substance can be a known surfactant which is arranged with the hydrophilic portion turned towards the water phase and the hydrophobic portion turned towards the molecular aggregate inside. The surfactants capable of forming micelles can be cationic, anionic, non-ionic or zwitterionic surfactants.
- Specific examples of suitable surfactants are sodium alkylsulphates of formula:
CH₃-(CH₂)n - 0 - SO₃ ⁻ Na⁺
wherein n is an integer ranging from 6 to 30;
and the alkyl-ammonium halides of formula:
CH₃(CH₂)n - N⁺ (R)₃ A⁻
wherein n is an integer of from 6 to 30, R is an alkyl radical containing from 1 to 3 carbon atoms and A⁻ is a halide ion such as bromide and chloride. - Suitable surfactants of the non-ionic type are, e.g., poly-(oxyethylene) alcohols or poly(oxyethylene) alkylphenols.
- Preferred examples of surfactants are sodium dodecylsulphate and dodecyl-trimethyl-ammonium chloride.
- If the amphiphilic substance exhibits a double alkyl chain, single-lamellar or multi-lamellar aggregation structures (which are called blisters or liposomes) are obtained.
-
- Microemulsions are composed of two immiscible liquids such as water and oil and of a surfactant and a co-surfactant, both arranged at the interface of the two immiscible liquids.
- Depending on whether the dispersed phase is oil or water, it is possible to obtain oil-in-water microemulsions or water-in-oil microemulsions. The microemulsions are stable, homogeneous and optically transparent and form spontaneously.
- Among the above heterogeneous systems, micelles and oil-in-water microemulsions are preferred in the cleaning process of the present invention.
- In particular, microemulsions have proved to be surprisingly effective. This system preferably consists of a microemulsion of an aliphatic hydrocarbon in water, stabilized with a surfactant of the non-ionic, anionic or cationic type and with a preferably alcoholic co-surfactant.
- A specific example of such a microemulsion is a system composed of dodecane in water and containing sodium dodecylsulphate as surfactant and pentanol as co-surfactant.
- By using the above heterogeneous systems it is possible to achieve a complete solubilization or to at least increase the solubility of hydrophobic compounds, as said systems contain compounds or molecular areas which are also hydrophobic and, therefore, capable of interacting with the hydrophobic substances to be solubilized. This is of particular importance when the continuous phase of the dispersion is water or an aqueous solution which by itself would be absolutely unsuited for solubilization. On the other hand, the hydrophilic phase of the dispersion is particularly suitable for the hydrophilic substrate onto which it has to act.
- The above systems have two different types of solubilization areas; in particular, in the micelles and in the blisters, the solubilization of the hydrophobic impurities occurs in molecular areas which are also hydrophobic while in the emulsions and microemulsions the solubilization occurs in areas substantially consisting of the hydrophobic oil phase dispersed in the hydrophilic matrix.
- All these systems act as solubilizers of the hydrophobic impurities, thus eliminating the drawbacks caused by the treatment of surfaces with organic solvents. Furthermore, all these systems are suitable for being applied onto hydrophilic substrates, such as those of wall surfaces and pictorial works in general, as they exhibit a continuous aqueous phase which secures the wetting of the hydrophilic matrices, and therefore their contact with the hydrophobic material, for a sufficiently long period of time.
- The cleaning process usually comprises the following steps carried out in the order given:
- onto the parts to be cleaned there are first applied compresses of cellulose or synthetic pulp saturated with water, which usually are kept in contact with said parts for about one to about two hours; during this step, the area of interest is saturated with humidity;
- subsequently, there are applied onto the selected parts compresses of cellulose or synthetic pulp saturated with a heterogeneous system such as, for example, the above microemulsion;
- the treated parts are sealed by means of duplex paper and/or a non-woven fabric in order to prevent both the evaporation of the volatile components of the heterogeneous system and the diffusion thereof beyond the selected area;
- the cellulose or synthetic pulp compresses are allowed to remain in contact with the surface to be cleaned for about 2 to about 6 hours.
- After removal of the compresses the hydrophobic impurities have been solubilized or at any rate detached from the substrate and are therefore readily and spontaneously removable.
- The cellulose pulp can, for example, be of a type such as ARBOCEL® BC or mixtures thereof with ARBOCEL® BWW. The synthetic pulp can, for instance, be composed of polyethylene and/or polypropylene fibrils.
- Naturally, instead of the cellulose or synthetic pulp, any other inert and absorbent substrate can be utilized such as, for example, fossil meal, micronized silicas etc.
- The duplex paper usually consists of an inner plastic material sheet, such as polyethylene (which is brought into contact with the surface to be treated), and of an outer cellulose sheet.
- An alternative method of application comprises causing the heterogeneous system to continuously flow, at a controlled flowrate, from a proper container (tank) to the area of interest - previously subjected to a humidification treatment - through a suitable micropiping, and removing the heterogeneous system downstream after solubilization of the hydrophobic impurities has occurred.
- Said method permits a continuous renewal of the solubilizing agent.
- The following non-limiting example is to further illustrate the present invention.
- A microemulsion was prepared by dispersing 0.08% by volume of dodecane in an aqueous solution of 0.5 moles of sodium dodecylsulphate and 1 mole of pentanol. Dodecane was gradually added under stirring. The system, opalescent at the beginning, became suddenly limpid after a few hours and remained in this state when maintained at a temperature ranging from 15 to 35°C.
- With reference to the attached figure, the fresco surface to be cleaned, containing splashes of wax (H), was first treated with a compress of cellulose pulp (type ARBOCEL BC 200®) impregnated with deionized water, in order to saturate the plaster surrounding the wax-coated area with humidity.
After two hours, the cellulose pulp compress was removed and replaced by a compress (A) composed of 70% of cellulose type ARBOCEL® BC 200 and 30% of cellulose pulp type ARBOCEL® BWW 40, impregnated with the water/sodium dodecyl sulphate/pentanol/dodecane microemulsion prepared as described above. - Compress (A) was surrounded by a compress (B) of cellulose pulp type ARBOCEL® BC 300 impregnated with dionized water, and the whole was coated with Japanese paper and cellulose pulp impregnated with water (C).
- The microemulsion was made to flow in contact with the surface to be cleaned from a bottle (L) through a pipe equipped with a flow regulator (I), the cannula (E) of said pipe being in contact with the part to be cleaned through a perforation in compresses (B) and (C). Compresses (B) and (C) were covered with a duplex paper consisting of a polyethylene film (D) and of a cellulose paper sheet (F) in order to prevent the components of the microemulsion from evaporating.
- In the part below the surface to be cleaned, and beneath the polyethylene film (D), a duplex paper sheet (G) was arranged, which consisted of a polyethylene layer in contact with the fresco and of an outer layer of cellulose paper. In this manner the polyethylene layer isolated the picture while the paper absorbed the excess microemulsion, thereby preventing it from dropping onto the underlying picture surface.
- After a treatment of about 4 hours it was observed that the treated part was completely clean and the splashes of wax had thoroughly been removed.
Claims (9)
- Process for cleaning hydrophilic porous matrices by means of solubilization of hydrophobic impurities, which comprises treating the surface to be cleaned with a dispersed heterogeneous system composed of dispersions of a liquid in another liquid, said dispersions being stabilized by amphiphilic substances, or of molecular aggregates of said amphiphilic substances dispersed in an aqueous medium or in aqueous electrolyte solutions.
- Process according to claim 1, wherein the dispersed heterogeneous system is in the form of emulsions, micelles, blisters or microemulsions.
- Process according to claim 2, wherein the emulsion is of the type oil-in-water or water-in-oil, said oil being a water-insoluble liquid, and the emulsion is stabilized with an emulsifier.
- Process according to claim 2, wherein the micelles are molecular aggregates of about 50 to about 100 molecular units of amphiphilic substances in an aqueous medium.
- Process according to claim 4, wherein the amphiphilic substances exhibit a double alkyl chain.
- Process according to claim 2, wherein the microemulsion is composed of two immiscible liquids and is stabilized by a surfactant and a co-surfactant, preferably of the alcoholic type.
- Process according to claim 6, wherein the microemulsion comprises dodecane in water and contains sodium dodecylsulphate as surfactant and pentanol as co-surfactant.
- Process according to anyone of the preceding claims, comprising the following sequence of steps:- applying onto the parts to be cleaned a compress of cellulose or synthetic pulp saturated with water and keeping said compress in contact with said parts for about one to about two hours;- subsequently applying onto said parts a compress of cellulose or synthetic pulp saturated with the heterogeneous system;- sealing the treated parts by means of duplex paper or a non-woven fabric;- removing the compress after about 2 to 6 hours.
- Process according to anyone of claims 1 to 7, wherein the heterogeneous system is caused to flow, at a controlled rate, from a container to the area of interest, which area had previously been subjected to a humidification treatment, through a micropiping, and removing the heterogeneous system downstream after the solubilization of the hydrophobic impurities has occurred.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
IT19912A IT1240734B (en) | 1990-04-02 | 1990-04-02 | PROCEDURE FOR CLEANING HYDROFILE POROUS DIES |
IT1991290 | 1990-04-02 |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0450539A2 true EP0450539A2 (en) | 1991-10-09 |
EP0450539A3 EP0450539A3 (en) | 1991-12-18 |
Family
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Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP19910105096 Withdrawn EP0450539A3 (en) | 1990-04-02 | 1991-03-28 | Process for cleaning hydrophilic porous matrices |
Country Status (2)
Country | Link |
---|---|
EP (1) | EP0450539A3 (en) |
IT (1) | IT1240734B (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2000054868A2 (en) * | 1999-03-12 | 2000-09-21 | The Court Of Napier University | A method for the extraction of oil by microemulsification |
Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE2319892A1 (en) * | 1972-04-20 | 1973-10-31 | Kao Corp | LIQUID DETERGENT MIXTURE |
DE2728464A1 (en) * | 1976-06-30 | 1978-01-05 | Nordtend Ab | PROCEDURES FOR THE PROTECTION AND CLEANING OF SURFACES SUBJECT TO CONTAMINATION WITH HYDROPHOBIC, IN PARTICULAR OILY SUBSTANCES |
EP0160762A1 (en) * | 1984-04-07 | 1985-11-13 | The Procter & Gamble Company | Stabilized oil-in-water cleaning microemulsions |
EP0263486A2 (en) * | 1986-10-06 | 1988-04-13 | LARAC S.p.A. | Improved compositions for the sulphation-removing cleaning of carbonatic lithoidal surfaces |
DE3637711A1 (en) * | 1986-11-05 | 1988-05-11 | Remmers Chemie Gmbh & Co | Composition for cleaning porous mineral building elements |
EP0268880A2 (en) * | 1986-11-03 | 1988-06-01 | LARAC S.p.A. | Cleaning pad for the removal of sulfates from frescoed surfaces |
-
1990
- 1990-04-02 IT IT19912A patent/IT1240734B/en active IP Right Grant
-
1991
- 1991-03-28 EP EP19910105096 patent/EP0450539A3/en not_active Withdrawn
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE2319892A1 (en) * | 1972-04-20 | 1973-10-31 | Kao Corp | LIQUID DETERGENT MIXTURE |
DE2728464A1 (en) * | 1976-06-30 | 1978-01-05 | Nordtend Ab | PROCEDURES FOR THE PROTECTION AND CLEANING OF SURFACES SUBJECT TO CONTAMINATION WITH HYDROPHOBIC, IN PARTICULAR OILY SUBSTANCES |
EP0160762A1 (en) * | 1984-04-07 | 1985-11-13 | The Procter & Gamble Company | Stabilized oil-in-water cleaning microemulsions |
EP0263486A2 (en) * | 1986-10-06 | 1988-04-13 | LARAC S.p.A. | Improved compositions for the sulphation-removing cleaning of carbonatic lithoidal surfaces |
EP0268880A2 (en) * | 1986-11-03 | 1988-06-01 | LARAC S.p.A. | Cleaning pad for the removal of sulfates from frescoed surfaces |
DE3637711A1 (en) * | 1986-11-05 | 1988-05-11 | Remmers Chemie Gmbh & Co | Composition for cleaning porous mineral building elements |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2000054868A2 (en) * | 1999-03-12 | 2000-09-21 | The Court Of Napier University | A method for the extraction of oil by microemulsification |
WO2000054868A3 (en) * | 1999-03-12 | 2001-03-01 | Univ Napier | A method for the extraction of oil by microemulsification |
Also Published As
Publication number | Publication date |
---|---|
IT9019912A0 (en) | 1990-04-02 |
EP0450539A3 (en) | 1991-12-18 |
IT1240734B (en) | 1993-12-17 |
IT9019912A1 (en) | 1991-10-02 |
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