Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B08—CLEANING
  • B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
  • B08B7/00—Cleaning by methods not provided for in a single other subclass or a single group in this subclass
  • B08B7/0014—Cleaning by methods not provided for in a single other subclass or a single group in this subclass by incorporation in a layer which is removed with the contaminants
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B08—CLEANING
  • B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
  • B08B3/00—Cleaning by methods involving the use or presence of liquid or steam
  • B08B3/04—Cleaning involving contact with liquid
  • B08B3/08—Cleaning involving contact with liquid the liquid having chemical or dissolving effect
• • 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
  • C11D17/04—Detergent materials or soaps characterised by their shape or physical properties combined with or containing other objects
  • C11D17/049—Cleaning or scouring pads; Wipes
• • 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
  • C11D7/00—Compositions of detergents based essentially on non-surface-active compounds
  • C11D7/02—Inorganic compounds
  • C11D7/04—Water-soluble compounds
  • C11D7/10—Salts
  • C11D7/12—Carbonates bicarbonates

Definitions

• the present invention relates to flexible coatings for the sulphation-removing cleaning of frescoed surfaces.
• the present invention relates to flexible coatings for the sulphation-removing cleaning of frescoed surfaces on plasters of prevailingly carbonatic nature.
• a classic method for removing the sulphation consists in acting on it with ammonium carbonate solutions, according to such modalities as not to endanger the integrity of the work of art, and in such a way as to restore a carbonatic surface, with the sulphate ion being removed as ammonium sulphate, by means of a double-exchange reaction.
• a subsequent treatment with barium hydroxide solutions is carried out, which causes a sulphate to be formed, having a low specific volume, and a high chemical inertness.
• barium hydroxide can turn again into barium carbonate, contributing to strengthen the plaster.
• Said formulates are carefully applied and removal by sponging and other delicate mechanical actions after rigorously controlled times of contact with the surfaces.
• compositions for the sulphation-removing cleaning and the analysis of the sulphation of frescoes surfaces comprising a mixture, generally having a paste form, of an aqueous solution of ammonium carbonate with an anion-­exchange resin in powder form.
• the granulometry of the ion-exchange materials must be carefully selected so to minimize their penetration into the microcavities and surface interstices.
• That need generally causes the increase of the particle size of the ion-exchange materials, with a consequent loss of effectiveness of the treatment, caused by a reduction in the contact surface areas.
• the not particularly small particle dimensions have a negative influence on the characteristics of spreadability and self-support of the paste-like mixtures, of not suitable consistency for the sulphation-­removing treatments.
• a protective layer such as, e.g., of light paper, non-woven fabrics, etc., with the effectiveness of the ion exchange being furthermore impaired, and/or to support the same paste by means of suitable gauze fabrics, non-woven fabrics, filter papers, and the like.
• the object of the present invention are therefore flexible coatings for the sulphation-removing cleaning of frescoed surfaces of prevailingly carbonatic nature comprising a fibrous support impregnated with a binding agent and with a paste-like mixture, comprising an aqueous solution of ammonium carbonate and/or bicarbonate and by an anion-exchange material in powder form.
• fibrous supports suitable for preparing the flexible coatings of the present invention comprise the filter papers, the papers endowed with high enough wet- resistance, the so-said dry-papers, i.e, those papers which are prepared from cellulose fibres and synthetic binding agents, cellulosic non-woven fabrics with or without synthetic fibres, woven fabrics endowed with the proper compactness, flexibility and hydrophily, of natural and/or synthetic fibres, such as wool, cotton, flax, jute, acrylic fibres, polyester fibres, polyolefinic fibres, and so forth.
• the anion-exchange material contains preferably the activated functional groups, e.g., in the form of aminic groups or quaternary ammonium bases, free, or salified, and particle dimensions preferably lower than 0.1 mm.
• anion-exchange materials are supplied by the anion-exchange synthetic resins, provided with basic functional groups, in particular, the resins with a matrix based on polymers or copolymers of styrene, of acrylic monomers or on polycondensation resins, or also on crosslinked and functionalized polysaccharides.
• the weight ratio of the anion-exchange material to the solution of ammonium carbonate and/or bicarbonate is comprised within the range of from 0.5 to 3.
• Suitable concentrations of the solutions of ammonium carbonate and/or bicarbonate have resulted to be those comprised within the range of from 1 to 20% by weight; this does not however constitute a limitation.
• Suitable binding agents which can be used in the preparation of the flexible coatings of the present invention comprise the aqueous dispersions of synthetic polymers and/or copolymers with particle charge compatible with that of the necessary anion-exchange materials.
• acetovinylic binding agents e.g., the ethylene-vinyl acetate (EVA) copolymers in practically non-ionic dispersion
• EVA ethylene-vinyl acetate
• polyurethanic binding agents always in non-ionic characteristics dispersion
• concentrations of the latexes comprised within the range of from 20 to 50% by weight
• the bin­ding agents comprise co-binding agents, also anionic, such as, e.g., the salified polymers of acrylic and/or methacrylic acid, in the form of ammonium salts.
• Useful additives for obtaining pastes suitable for coating the fibrous supports can be the kaolinites, the attapulgites, the clay materials in general, with a sufficiently fine granulometry and with a high water retention, at concentrations around 20% by weight relatively to the fine exchange-resin.
• Useful dimensions have demonstrated to be those equal to, or lower than, 100 micrometres; this is not, however, a limitative criterion.
• These mineral additives can be useful for improving the rheologic behaviour of the paste and make it possible a more regular application thereof.
• surface-active compounds both of non-ionic and cationic type, can result useful, for improving the wettability of the components, as well as the germicidal compounds, from quaternary ammonium bases, in the amounts which are regarded as being the most suitable.
• the impregnation of the fibrous support can be accomplished by means of known techniques, such as, e.g., by means of spreading means, brushes, palette-knives, doctors, rollers, spraying equipment, etc., with the desired amounts being deposited.
• the so-obtained coating is dried and exsiccated at a mild temperature, generally not higher than 50°C, and is stored for long time periods.
• the coating When the coating is used, it is reconditioned, e.g., by dipping in demineralized water, or in suitable solutions of ammonium carbonate and/or bicarbonate, and is directly applied into contact, from the ion-exchange material side, with the frescoed surface to be treated, thus all of the problems being overcome, which derive from the use of materials having a consistency and rheological characteristics unsuitable for obtaining self-supporting preparates.
• the flexible coating of the present invention can be used again for sulphation-removing treatments, after a preliminary reactivation by digestion in regenerating solutions, such as, e.g., the ammonium carbonate and/or bicarbonate solutions may be, until the physical-mechanical characteristics of the same coating allow so doing.
• regenerating solutions such as, e.g., the ammonium carbonate and/or bicarbonate solutions may be, until the physical-mechanical characteristics of the same coating allow so doing.
• the flexible coating of the present invention can be obtained by impregnating the fibrous support with a paste of an anion-­exchange material in powder form and water, and a binding agent.
• the impregnated support is dried and exsiccated at a mild temperature, generally not higher than 50°C, and is stored for long time periods.
• the coating When used, it can be reconditioned by means of demineralized water, or in suitable aqueous solutions of ammonium carbonate and/or bicarbonate, with concentrations comprised, e.g., within the range of from 1 to 20% by weight.
• the reconditioning in demineralized water can be necessary in case of treatments of particularly deteriorated frescoed surfaces, so that it is preferable to operate with low-aggressivity coatings. That means eliminating the ammonium salt and operating in the presence of the anion-­exchange material only.
• the flexible coating of the present invention performs its action in the presence of aqueous phase, so, it could be useful, for some applications, to slow down the exsiccation rate thereof, by means of sheets of plastic films, or supplying water or carbonate-containing solution by means of pads or imbibition by capillarity.
• Useful modifications which do not endanger the originality of the invention are: - variations in granulometry and in type of exchange materials; - variations in the ratio of the anion-exchange material to the ammonium carbonate and/or bicarbonate solution; - variations in concentration of ammonium carbonate and/or bicarbonate; - use of detergent, non-ionic or cationic surface-active agents with also germicidal action.
• a preparate obtained according to the following modalities and composition, was spread on dry-paper of approximately 45 g/m2, with the aid of a brush. After drying and exsiccation the coating deposit resulted equal to an average of approximately 70 g/m2.
• the modalities of preparation of the preparate are:
• the following ingredients are prepared and mixed with one another: 75 parts of acetovinylic (EVA) latex Vinnapas EP14 by WACKER, 75 parts of demineralized water, 4 parts of an acidic acrylic latex Crilat D159 by VINAVIL, 80 parts of a 15% solution of ammonium carbonate; this for­mulation is added, with suitable stirring, to the paste of water and anion-exchange resin.
• EVA acetovinylic
• the obtained coating after exsiccation, was washed in a stream of demineralized water and was conditioned in a 7% ammonium carbonate solution.
• Two layers of a preparate, obtained according to the following modalities were applied, by brush, on dry-paper of about 45 g/m2 and on cotton cloths of about 100 g/m2 of weight.
• the coating deposits were respectively of about 110 and 140 g/m2.
• the following ingredients are prepared by mixing, in the order: 75 parts of acetovinylic (EVA) latex Vinnapas EP14 by WACKER, 80 parts of demineralized water, 4 parts of a 15% solution of ammonium carbonate; this formu­lation is added, with suitable stirring, to the paste of water and anion-exchange resin.
• EVA acetovinylic
• the coatings on the basis of supported anion-exchange material, obtained as said above, were dried, washed in a stream of demineralized water, and conditioned in 7% ammonium carbonate solutions.
• the sulphation was removed from a portion of the frescoed surface of the Brancacci chapel of Florence, together with the proteinic substances with which the same surfaces had been treated on the occasion of prior restorations.
• a preparate, obtained according to the following modalities was applied, by palette-knife, on dry-paper of about 45 g/m2.
• the coating deposits were of the order of 80 g/m2 on the average.
• the coating on the basis of supported anion-exchange material was submitted, after drying, to a washing in a stream of demineralized water, and a part thereof was then conditioned in a 12% ammonium carbonate solutions.
• the coating of the invention after washing in a stream of demineralized water, and conditioning in a 5% solution of ammonium carbonate, was applied both on a surface of sulphonated limestone, and on a frescoed surface of 1400. In both cases, it was possible to document cleaning and sulphation-removing effects, by means of visual inspections and chemical analyses.

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Organic Chemistry (AREA)
• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Wood Science & Technology (AREA)
• Inorganic Chemistry (AREA)
• General Chemical & Material Sciences (AREA)
• Cleaning Implements For Floors, Carpets, Furniture, Walls, And The Like (AREA)
• Treatment Of Fiber Materials (AREA)
• Detergent Compositions (AREA)
• Chemical Or Physical Treatment Of Fibers (AREA)
• Polishing Bodies And Polishing Tools (AREA)
• Laminated Bodies (AREA)
• Brushes (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (3)

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ID=11193166

Family Applications (1)

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Cited By (5)

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• 1986
  • 1986-11-03 IT IT22215/86A patent/IT1200526B/it active
• 1987
  • 1987-11-03 EP EP87116146A patent/EP0268880B1/de not_active Expired - Lifetime
  • 1987-11-03 AT AT87116146T patent/ATE90113T1/de not_active IP Right Cessation
  • 1987-11-03 PT PT86067A patent/PT86067B/pt not_active IP Right Cessation
  • 1987-11-03 DE DE87116146T patent/DE3786060T2/de not_active Expired - Fee Related

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