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Title:
METHOD FOR THE IMPREGNATION OF ASBESTOS IN VIEW OF THE REMOVAL, TRANSPORT AND DISPOSAL THEREOF
Document Type and Number:
WIPO Patent Application WO/2005/110632
Kind Code:
A1
Abstract:
Method for the impregnation and rapid and safe removal of asbestos fibers from structures contaminated or coated with said fibers. The method provides for the use of a new non-toxic, non-flammable and easy-to-apply impregnating product comprising the following components: a) organic oligomers, telomers and monomers with molecular weight included in a range of 100 to 5000, preferably in a range of 150 and 1000, and containing functional groups of the epoxy, hydroxy, acid, acrylic, methacrylic and allyl type; b) organic oligomers, telomers and monomers with molecular weight included in a range of 100 to 5000, preferably in a range of 150 and 3000, and containing functional groups capable of reacting with said component a).

Inventors:
LOCASPI ANGELO (IT)
Application Number:
PCT/EP2005/005326
Publication Date:
November 24, 2005
Filing Date:
May 16, 2005
Export Citation:
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Assignee:
INNOVENTIONS S R L (IT)
LOCASPI ANGELO (IT)
International Classes:
B08B7/00; B09B3/00; (IPC1-7): B09B3/00; A62D3/00; E04G23/00
Foreign References:
EP0455866A11991-11-13
EP0688923A11995-12-27
DE19509708A11996-09-12
DE4344478A11995-06-22
US3519594A1970-07-07
Other References:
PATENT ABSTRACTS OF JAPAN vol. 013, no. 399 (C - 632) 5 September 1989 (1989-09-05)
PATENT ABSTRACTS OF JAPAN vol. 014, no. 197 (C - 0712) 23 April 1990 (1990-04-23)
PATENT ABSTRACTS OF JAPAN vol. 015, no. 512 (C - 0898) 26 December 1991 (1991-12-26)
Attorney, Agent or Firm:
Zanoli, Enrico (Viale Bianca Maria 35, Milano, IT)
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Description:
METHOD FOR THE IMPREGNATION OF ASBESTOS IN VIEW OF THE REMOVAL, TRANSPORT AND DISPOSAL THEREOF DESCRIPTION The invention relates to a method for the rapid impregnation of dry asbestos fibers conventionally used as an insulating and/or intumescent coating on metal or concrete structures. Sprayed (or friable) asbestos was applied in layers of a few centimeters (usually 3 - 5 cm) up until the 1960s on all civil and industrial structures, as it was the most economical and efficient insulating and intumescent agent available on the market. When it was proven that the asbestos fiber was the cause of pleural mesothelioma, the law established that all asbestos installed in previous decades years must first be contained and subsequently removed. Currently, the removal of sprayed asbestos from surfaces coated therewith, transfer thereof from the place of removal to the place of disposal and disposal thereof represent an extremely high health hazard for all operators involved in these three executive phases, as removal is only possible by means of mechanical action. This way of operating inevitably releases a large quantity of asbestos fibers which are dispersed in the air and, consequently, into the environment. All the protections and procedures established by law to protect operators and the environment (containment of the work area, suits, masks, showers, etc), besides being extremely costly, are not totally effective and there is still an impending risk of contact with asbestos fibers. To lessen the danger and facilitate removal of the asbestos, various methods have been proposed, essentially based on the principle of wetting the layer of asbestos with specific fluids to prevent dispersion of the fibers into the air during the phase to remove the coating. Although the fluids proposed facilitate the removal phase they do not however guarantee safety during the subsequent phases (removal from the premises, transport and disposal) as they have no encapsulating action on the asbestos fibers. The fluids currently used do not coat and aggregate the fibers together as they are solutions of propylene glycol, proteins or glucose, etc., or polymer emulsions or latexes which, due to the high molecular weight and dimension of the primary particles of the dispersions, are unable to penetrate in-depth into the weave of the asbestos fibers. A compact surface skin is formed containing therewithin the original fibrils free to be dispersed into the environment and cause damage to the health of the operators and anyone else unintentionally transiting in areas in which asbestos is being removed. The object of the present invention is a new method for the removal of sprayed asbestos which allows to solve the above mentioned problems. In particular, it is an object of the present invention to provide a method which allows the fibrils to be aggregated permanently without dispersion into the environment and without causing damage to the health of operators. The above objects are achieved thanks to a new method, according to the invention, for the impregnation of asbestos according to the appended claim 1. In the method of the invention, absorption of a specific reactive and penetrating fluid by the sprayed asbestos is particularly rapid. In some cases, the increase in weight is such that the asbestos detaches spontaneously from the support, thereby simplifying the removal operation. After evaporation of the dilution solvent, usually water or mixtures of water and ethyl alcohol, i.e. about 4 - 12 hours after application of the fluid according to the invention, the blocks of asbestos have dimensions of a few centimeters, are not friable and are easy to handle for subsequent transport and disposal operations. All this takes place with almost no release of fibers into the environment. The fluid used in the method of the present invention is a mixture that comprises the following components: a) organic oligomers, telomers and monomers with low molecular weight included in a range of 100 to 5000, preferably between 150 and 1000, preferably soluble in hydroalcoholic solutions and containing functional groups of the epoxy, hydroxy, acid, acrylic, methacrylic and allyl type; b) organic oligomers, telomers and monomers with low molecular weight included in a range of 100 to 5000, preferably between 150 and 3000, preferably soluble in hydroalcoholic solutions and containing functional groups capable of reacting with the substances described in the previous point having functionality of the amine, amide, polysulfide, isocyanate, peroxide type. Components a) and b) are preferably used in the form of solutions in suitable solvents, preferably water and/or an alcohol, which is preferably ethyl alcohol. According to a preferred embodiment of the method of the invention, component a) is a hydroalcoholic solution of organic oligomers or telomers containing epoxy functional groups and having a molecular weight between 150 and 1000, more preferably between 200 and 600. Preferably the solution contains between 50 and 80% by weight of component a), more preferably between 60 and 75% by weight. The preferred component b) to be used in combination with the above-mentioned component a), is a hydroalcoholic solution of organic oligomers or telomers containing amine functional groups and having a molecular weight between 150 and 3000, more preferably between 200 and 2000. Preferably the solution contains between 2 and 20% by weight of component b), more preferably between 5 and 15% by weight. Preferably the fluid to be used in the method according to the present invention contains one or more additives or colorants. In practical terms, the method according to the present invention comprises the following steps: preparation of the area to be treated in accordance to applicable laws, for example in accordance with the provisions of art. 34 Legislative Decree 277/91 Law 257/92 and implementing Ministerial Decree 06/09/94; preparation of the treatment fluid by mixing components a) and b) in suitable ratios; application of a first coat of the Product on the surface to be treated, by low pressure spraying, so as to prevent disturbing the state of the fibers and avoid raising dust; after a suitable time, e.g. 30 - 60 minutes after application of the first coat, repeating the operation in areas in which the thickness of the sprayed asbestos is presumed to be greater than 1.5 - 2.0 cm; it is also possible to inject the treatment fluid in areas in which the asbestos is presumed to be particularly thick and which cannot be reached simply by spraying it from the outside; in the case of detached blocks of asbestos, the reverse side of the blocks, i.e. the side not treated by spraying, is also preferably treated with the treatment fluid; after a suitable time, e.g. 6 - 24 hours after application as indicated in the previous points, removal of the asbestos fibers impregnated and aggregated with the Product according to one or more of the following procedures: vacuuming using a specific machine; manual removal of the undetached asbestos fibers by means of a spatula or equivalent means; collection and packaging of detached asbestos blocks. The method according to the invention has the following advantages. The treatment fluid of the invention is capable of in-depth penetration of the network of asbestos fibers and of coating said fibers where said monomers, telomere and oligomers are transformed, in a temperature range from 2 to 200°C, preferable from 0 to 50°C, into polymers with an extremely high molecular weight through reaction between the components a) and b) within a few hours of application. Moreover, the telomer, oligomer and monomer of components a) and b), when diluted with water or mixtures of water and alcohol brings about a mixture which rapidly saturates the asbestos through capillarity and, additionally, does not produce harmful vapors during the application and drying phase. Thanks to the above, the treatment fluid rapidly produces total saturation of the layer of asbestos so that the coating tends to detach spontaneously from the support due to the substantial increase in the weight thereof. Also, the material which is formed following the reaction between components a) and b) in the mass of asbestos treated is insoluble and the mechanical properties after polymerization are sufficient to compact the mass of fibers detached from the support, but not sufficiently high to make difficult the mechanic removal of parts that have not detached spontaneously from the support. It has also been found that the treatment fluid has high adhesiveness on the fibers and produces a homogeneous plastic mass which makes the air-dispersion of asbestos fibers and fibrils impossible during the aforesaid phases. The procedure described hereinbefore is advantageously applicable where the removal of sprayed asbestos or similar materials such as mineral wools is required. These requests come from the building world, principally from the field of extraordinary maintenance of buildings, but also in sectors such as the energy, oil, ship maintenance and transport industries. EXAMPLES General conditions The site in which the treatment method of surfaces sprayed with asbestos was performed, was prepared in accordance with the provisions contained in the above-mentioned Italian Ministerial Decree 06/09/94. EXAMPLE 1 (comparison): DRY REMOVAL During an operation to remove sprayed asbestos from a civil building, a surface of approximately 5 m2 was identified to be used as a test area. For dry removal the following procedures were used: 1. Dry removal was started from the point farthest from the exhaust fans and proceeded towards them, in the direction of air flow, so that the fibers released during the operation were moved away from areas already decontaminated. 2. Large-scale removal of most of the coating then took place using metal scrapers and other manual means. In order to avoid fiber dispersion and in accordance with the law provisions, these tools did not use compressed air and were operated at low speed. 3. One or more operators, standing on a scaffold, removed the coating of the substrate, while other operators on the ground collected the material falling on the floor and bagged it using brushes and plastic dustpans to avoid damaging the polythene sheeting; as work proceeded, the operators on the ground moved the mobile scaffold; when the surfaces to be treated were of considerable height, the asbestos removed was dropped into a collection plate as close as possible to the surface to be treated and connected by piping to bags placed on the floor. 4. In the final phase residues still attached to the substrate were removed; in this phase the surfaces were wet brushed and subsequently vacuumed with absolute filter vacuum cleaner. Removal speed ranged from 0.1 to 0.5 m2/hour, and the concentration of asbestos fibers in the air was approximately 500 - 1000 fibers/liter. EXAMPLE 2 (comparison): WET REMOVAL During an operation to remove sprayed asbestos from a civil building, a surface of approximately 5 m2 was identified to be used as a test area. For wet removal the following procedures were used: 1. An impregnating product such as Litoconam 03 by the firm Roofing Italiana S.r.l. was applied through low pressure spraying, in the amount of 2 — 2.5 kg/m2. 2. The entire asbestos coating was soaked, to obtain impregnation of the material for the entire thickness; in addition to the product mentioned in the previous point, surfactant or saturating acrylic and vinyl products diluted in water can also be used. In accordance with the law provisions the sprayed asbestos was wetted with a "vaporized" widespread jet using an airless pump at low pressure. The material was sprayed a first time to wet the surface, then a second time to obtain saturation. 3. The encapsulating solution was left to act by "penetration" for an adequate time of 12 hours. 4. One or more operators, standing on scaffold, removed the soaked asbestos from the substrate, while other operators on the ground collected the material dropped to the floor and bagged it before it had time to dry; 5. As work proceeded, the operators on the ground moved the mobile scaffold; when the surfaces to be treated were of considerable height, the asbestos removed was dropped into a collection plate placed as close as possible to the surface to be treated. 6. In the final phase residues still attached to the substrate were removed; in this phase the surfaces were wet brushed and subsequently vacuumed with an absolute filter vacuum cleaner. Removal speed was around 2 m2/hour, and the concentration of asbestos fibers in the environment was approximately 100 fibers/liter. EXAMPLE 3 (invention) During an operation to remove sprayed asbestos from a civil building, a surface of approximately 5 m2 was identified to be used as a test area of the method according to the present invention. Part of this surface was horizontal (i.e. ceilings, beams), and the remaining part vertical (walls, pillars). The following procedures were used: 1. 20 parts by weight of hydroalcoholic solution containing 70% of organic oligomers or telomers containing epoxy functional groups and having a molecular weight between 250 and 500 were mixed with 100 parts by weight of a hydroalcoholic solution containing 9% of organic oligomers or telomers containing amine functional groups and having a molecular weight between 400 and 200. 2. The above-obtained treatment fluid was applied using low pressure spraying, in the amount of 1.5 - 2.0 kg/m2. 3. 30 - 60 minutes after application of the first coat, a second coat of treatment fluid was applied to soak the asbestos in depth. 4. An operator then removed the partially adhered asbestos remaining on the support manually or using a vacuum cleaner, and dropping the impregnated asbestos on the ground. 5. The impregnated asbestos was left to dry on the floor for approximately 24 hours. 6. After this time the operator collected the asbestos, which had taken a plastic, compact consistency and did not release fibers, and placed it in bags. Removal speed was around 10 m2/hour, and the concentration of asbestos fibers in the environment was approximately 10 fibers/liter.