EP1620673A2 - Method of coating the inner wall of a pipe with a latex film - Google Patents

Method of coating the inner wall of a pipe with a latex film

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Publication number
EP1620673A2
EP1620673A2 EP04742560A EP04742560A EP1620673A2 EP 1620673 A2 EP1620673 A2 EP 1620673A2 EP 04742560 A EP04742560 A EP 04742560A EP 04742560 A EP04742560 A EP 04742560A EP 1620673 A2 EP1620673 A2 EP 1620673A2
Authority
EP
European Patent Office
Prior art keywords
latex
pipe
monomers
water
internal wall
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.)
Withdrawn
Application number
EP04742560A
Other languages
German (de)
French (fr)
Inventor
Hélène BLAISE-GRAFTIEAUX
Gérard Riess
Philippe Marteil
Jean-Marie Schwob
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
D'etudes De Travaux Hydrauliques Et D'addu Ste
Solvay Solutions UK Ltd
Original Assignee
ANJOU RECH
Anjou Recherche
Rhodia UK Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by ANJOU RECH, Anjou Recherche, Rhodia UK Ltd filed Critical ANJOU RECH
Publication of EP1620673A2 publication Critical patent/EP1620673A2/en
Withdrawn legal-status Critical Current

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
    • F16L55/00—Devices or appurtenances for use in, or in connection with, pipes or pipe systems
    • F16L55/16—Devices for covering leaks in pipes or hoses, e.g. hose-menders
    • F16L55/162—Devices for covering leaks in pipes or hoses, e.g. hose-menders from inside the pipe
    • F16L55/165—Devices for covering leaks in pipes or hoses, e.g. hose-menders from inside the pipe a pipe or flexible liner being inserted in the damaged section
    • F16L55/1656—Devices for covering leaks in pipes or hoses, e.g. hose-menders from inside the pipe a pipe or flexible liner being inserted in the damaged section materials for flexible liners
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
    • B05D7/22—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials to internal surfaces, e.g. of tubes
    • B05D7/222—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials to internal surfaces, e.g. of tubes of pipes
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D133/00—Coating compositions based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Coating compositions based on derivatives of such polymers
    • C09D133/04—Homopolymers or copolymers of esters
    • C09D133/06—Homopolymers or copolymers of esters of esters containing only carbon, hydrogen and oxygen, the oxygen atom being present only as part of the carboxyl radical
    • C09D133/08—Homopolymers or copolymers of acrylic acid esters
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D135/00—Coating compositions based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a carboxyl radical, and containing at least another carboxyl radical in the molecule, or of salts, anhydrides, esters, amides, imides or nitriles thereof; Coating compositions based on derivatives of such polymers
    • C09D135/06—Copolymers with vinyl aromatic monomers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
    • F16L58/00—Protection of pipes or pipe fittings against corrosion or incrustation
    • F16L58/02—Protection of pipes or pipe fittings against corrosion or incrustation by means of internal or external coatings
    • F16L58/04—Coatings characterised by the materials used
    • F16L58/10—Coatings characterised by the materials used by rubber or plastics
    • F16L58/1009—Coatings characterised by the materials used by rubber or plastics the coating being placed inside the pipe
    • F16L58/1045—Coatings characterised by the materials used by rubber or plastics the coating being placed inside the pipe the coating being an extruded or a fused layer

Definitions

  • the present invention relates to a method of coating the internal wall of a pipe with a protective film comprising the formation of this film from at least one latex.
  • the invention also relates to the use of latex to form a film intended for coating the internal wall of a pipe to reduce or eliminate the release of one or more constituents of the material of said pipe in a liquid led by the latter. .
  • a pipe, a pipe or a portion of pipe whose inner wall is coated with a film obtained from at least one latex represents further objects of the invention.
  • the method according to the invention is particularly applicable to a water supply pipe, in particular drinking water, preferably having a temperature below about 30 ° C, in particular less than or equal to about 20 ° C.
  • the method according to the invention finds a particularly advantageous application for the coating of metal pipes, in particular lead pipes.
  • the water leaving the supply station is always below this limit of 10 ⁇ g / l but is loaded with lead element by passing through the old pipes.
  • the film must have the following characteristics to correspond to the identified need: impermeability to water and lead, adhesion to used lead, that is to say untreated and having been attacked by drinking water, or possibly stripped , sufficient flexibility to withstand hose twists, - service life greater than 10 years.
  • the polymer which constitutes it must meet the following requirements: be made from chemical compounds (monomers, initiators, additives) falling within the "food quality" standards, in the case of coating the internal wall of a pipe intended for the drinking water supply, have good chemical resistance to water and chlorine.
  • the process must be as simple as possible to limit successive operations increasing the cost of the operation, suitable for application in pipes of both small and large diameters, as well as on a network comprising fittings and branches. , and allow the coating of the pipeline in a short time, in order to limit the duration of the water cut as much as possible.
  • the film must be formed under conditions of temperatures close to ambient.
  • Lining with a polymer is already a technique used in the field of internal pipe coatings.
  • patent DE 4012605 describes a process for repairing and sheathing of waste water pipes, for public or industrial use.
  • the coating consists of a bituminous emulsion containing a dispersion of poly (chlorobutadiene) and possibly other polymers, such as natural resins, poly (vinyl propionate or acetate) or polyvinyl alcohol.
  • the dispersion is applied as a spray and drying is ensured by a current of hot air.
  • a liquid epoxy resin is circulated, after an abrasive cleaning, in the pipes, going from the smallest to the largest diameters.
  • the sufficient quantity of resin calculated for a pipeline or a stage, is pushed inside the pipeline by compressed air.
  • the resin is heated by a stream of hot air.
  • French patent FR 2 728 652 relates to a process for the internal coating of small diameter pipes in which an epoxy resin is pushed by a flexible pad with a diameter slightly smaller than that of the pipes. The regular movement of the resin + buffer assembly is ensured by a small pressure difference.
  • Application GB 1 322 122 relates to a method for sealing leaks in pipes, in particular by applying natural or synthetic latex.
  • the resins used generally have a "pot-life", that is to say a lifetime in the container of use, of short duration, which makes their use not very easy.
  • the use of at least one latex to form a film coating the internal wall of a pipe overcomes these constraints, while meeting official requirements for organic material that can be used in fixed installations for the distribution, treatment and production of water, in particular water intended for consumption, namely in particular the migration limit on the part of the finished material, the organoleptic quality of the water, the bacterial inertia (no contribution to the formation of a biofilm) and the absence of cytotoxicity.
  • the latex used to form the film is such that, when it is diluted to 20% of dry extract in demineralized water, its conductivity is less than 1.3 mS / cm.
  • the conductivity of said latex diluted to 20% of dry extract in demineralized water will be less than 1 mS / cm, preferably less than 0.9 mS / cm.
  • latex diluted to 20% of dry extract in demineralized water means a latex reduced to a solid level of 20% by adding demineralized water.
  • Conductivity is measured using a conductivity meter at a temperature of 20 ° C.
  • latex in the present description is meant a suspension of polymer particles generated in situ in a continuous phase consisting of an aqueous solvent, preferably water or a water / cosolvent mixture, for example an alcohol.
  • the particle diameter is of the order of 10 nm to 5 ⁇ m, in particular from 100 to 300 nm.
  • the monomers chosen from styrene and its derivatives, butadiene, chloroprene and esters are used more specifically according to the invention as ethylenically unsaturated monomer to form the latex.
  • (meth) acrylic esters is meant the esters of acrylic acid or methacrylic acid with hydrogenated or fluorinated C ⁇ -C 12 alcohols, preferably Ci-C ⁇ .
  • C ⁇ -C 12 alcohols preferably Ci-C ⁇ .
  • Vinyl nitriles more particularly include those
  • C 3 -C ⁇ 2 such as in particular acrylonitrile and methacrylonitrile.
  • styrene can be replaced in whole or in partly by derivatives such as alphamethylstyrene or vinyltoluene.
  • the other ethylenically unsaturated monomers which can be used alone or in mixtures or which can be copolymerized with the above monomers are in particular: - vinyl esters of carboxylic acids such as vinyl acetate, vinyl versatate, vinyl propionate, halides vinyl, ethylenic unsaturated mono- and dicarboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid and the mono-alkyl esters of dicarboxylic acids of the type mentioned with alkanols preferably C ⁇ -C and their N-substituted derivatives, amides of unsaturated carboxylic acids such as acrylamide, methacrylamide, N-methylolacrylamide or methacrylamide, N-alkylacrylamides, - ethylenic monomers comprising a sulfonic acid group and its alkali or ammonium salts, for example vinylsulfonic acid, vinylbenzene sulf
  • zwitterionic monomers such as for example sulfopropyl (dimethyl) aminopropyl acrylate.
  • zwitterionic monomers such as for example sulfopropyl (dimethyl) aminopropyl acrylate.
  • Monomers allowing crosslinking during processing, for example by chemical, thermal or photochemical means, such as glycidyl methacrylate or dihydrodicyclopentadienyl acrylate.
  • said latex is preferably formed by polymerization or copolymerization of food grade monomers. Lists of approved monomers are available country by country.
  • Advantageous food grade monomers are chosen from methacrylic esters, in particular n-butyl acrylate, methacrylic acid and its derivatives; styrene and its derivatives.
  • said latex comprises a polymer or a copolymer having a film-forming temperature of between 0 ° C and 20 ° C.
  • said latex comprises a polymer or a copolymer having a glass transition temperature (T g ) of less than 20 ° C, and even more preferably of a glass transition temperature of between 0 ° C and 10 ° C.
  • T g glass transition temperature
  • the latex which can be used for the purposes of the invention advantageously has a high level of solids, in particular greater than or equal to 20%, in particular from 30 to 50%.
  • Another advantageous property of said latex is to have a low level of coagulum, in particular less than 10%, preferably less than 0.1%. The level of solids and the level of coagulum are determined as indicated in Example 1.
  • the latex before its use to form a film, is subjected to a purification treatment intended to reduce the concentration of water-soluble constituents of said latex.
  • water-soluble constituent is meant in the present description the residual monomers remaining in the solvent after polymerization, the oligomers comprising approximately 2 to 10 monomeric units, the salt residues originating from the polymerization initiators, the ions originating from the polymerization buffer and , when surface-active agents are used during the formation of the latex, those of them which are not involved in the stabilization of the polymer particles, as well as any other constituent which remains in solution in the continuous phase at the resulting from the formation of latex.
  • This purification treatment is advantageously carried out by dialysis and / or ultrafiltration.
  • the method of coating the internal wall of a pipe comprises the following steps: filling a pipe with latex, draining said pipe so as to allow the overflow to flow latex and to form a layer of latex on the internal wall of the pipe, - the latex layer is heated so as to form the protective film on the internal wall of said pipe.
  • the latex has a lifespan of several hours, making its use particularly easy.
  • the filling of the pipe is for example carried out at room temperature.
  • the heating of the latex layer so as to form the protective film can be carried out at a temperature of the order of 30 to 80 ° C.
  • the internal wall of the pipe can be coated with several superimposed latex films, in particular with two superimposed latex films.
  • each of the latex films is applied after drying of the preceding film, each of the films has a thickness of approximately 50 to 500 ⁇ m, preferably 100 to 250 ⁇ m.
  • the filling of the pipe can advantageously be carried out under pressure, for example a pressure of 2 to 50 Pa.
  • the lining of the internal wall of the pipe can be carried out on the pipe as it is, without prior treatment of the latter.
  • the pipes or pipe portions thus coated have improved torsional strength properties compared to pipes coated with resins, such as certain epoxy resins, due to the elastic properties of latex.
  • the latex capable of being used for the purposes of the invention can be obtained by conventional methods.
  • the reagents used to obtain a latex which can be used for the purposes of the invention are those used conventionally in the emulsion polymerization technique. This involves four main constituents: the dispersion medium (or continuous phase), the surfactant (s); conventionally up to 0.01 to 10% by mass relative to the monomer (s), depending on the type of stabilization, the monomer (s), the initiator, soluble in the dispersing medium, generally at height of 0.5 to 2% by mass relative to the monomer (s).
  • Chain transfer agents Mention may in particular be made of chain transfer agents, buffering agents for controlling the pH of the medium, and chelating agents.
  • the dispersion medium generally consists of water or a water / cosolvent mixture such as an alcohol, in particular methanol, in which the constituents are dispersed or dissolved.
  • the surfactant is first dissolved in the aqueous phase, leading to the formation of a micellar solution, if the surfactant concentration is sufficient (critical micellar concentration).
  • ionic surfactants will be used, especially anionic surfactants such as sodium alkylsulfonates.
  • Non-ionic surfactants can also be used, as well as macromolecular surfactants consisting of block copolymers comprising a block based on poly (ethylene oxide) (POE), linked to a hydrophobic block composed of a polymer chain. , such as poly (styrene) (PS) or poly (methyl methacrylate) (PMMA).
  • POE poly (ethylene oxide)
  • PS poly (styrene)
  • PMMA poly (methyl methacrylate)
  • the hydrophilic part can also be, instead of a POE chain, an anionic or cationic hydrophilic sequence.
  • the monomers are added to this micellar solution, and stabilized using the surfactant.
  • the latexes which can be used for the purposes of the invention can be derived from the copolymerization of several monomers, in order to benefit from a wide range of modular properties. These can in particular be more or less water-soluble.
  • the initiators generally come from the category of peroxides, in particular inorganic (H 2 O 2 , K 2 S 2 O ⁇ ).
  • the most widely used initiator is potassium or sodium persulfate. It can be combined with a redox couple such as (Fe 2+ / Fe 3+ ) in order to be able to lower the polymerization temperature.
  • the buffers allow the polymerization medium to be kept at a constant pH throughout the reaction. Regulation of the pH also makes it possible to avoid the formation of certain ionic associations which would prevent the completion of the reaction.
  • Chain transfer agents are used to control the average molecular weight of the polymer and to prevent crosslinking.
  • an alkyl mercaptant of general formula R-SH will be used.
  • Chelating agents may also prove to be necessary to render inactive certain metal ions liable to disturb the polymerization and are chosen according to the type of ion and the pH of the medium.
  • latexes which can be used for the purposes of the invention can be functionalized, that is to say that reactive or ionizable functions are covalently linked to the surface of the particles.
  • This functionalization can be carried out: by incorporation of reactive chemical groups carried by the radical initiator (sulphate or carboxylate are the most frequent), - by stabilization of ionic or non-ionic surfactants of the "surfmers” type, by post-polymerization chemical modification , or by incorporation of functional monomers in the chains by copolymerization.
  • functionalization will be used with carboxylic monomers, such as acrylic and / or methacrylic acids to improve the adhesion and promote the interactions of latexes with substrates, in particular metallic.
  • the synthesis of the latex can be carried out in a closed reactor, known as "batch" mode, in which all the components (water, surfactant, monomer, optional buffer) necessary for the synthesis are introduced into the reactor before initiating the reaction, that this being carried out at given temperature and stirring.
  • a commercially available latex can also be used for the purposes of the invention.
  • said latex will be subjected to a purification treatment by dialysis and / or ultrafiltration prior to its use for coating the internal wall of a pipe.
  • the latex diluted for example to 20% is introduced into a recirculation tank and it is passed through an ultrafiltration module at a speed between 1 to 5 m / s at room temperature and a pressure between 1 and 5 is applied. bars.
  • the ultrafiltration module can be used with mineral or organic membranes, with a cutoff threshold (pore size) adapted to the latex used.
  • the latex is purified by diafiltration until the required purity is obtained.
  • the latex is sufficiently purified from the moment when the conductivity approaches the threshold where it is constant.
  • This value depends on the latex used and its initial dilution state.
  • the latex is sufficiently purified when its conductivity is less than 1.3 mS / cm, preferably less than 1 mS / cm , and even more preferably less than 0.9 mS / cm.
  • the temperature is regulated by means of a water bath thermostatically controlled at a temperature of 70 ° C. Stirring can be adjusted to different values between 0 and 1000 rpm. The most common agitation is 250 to 300 rpm.
  • the reactor is surmounted by a coolant, and a nitrogen inlet allowing the degassing of the entire system and the solutions.
  • the addition is done by means of syringes and syringe pumps, allowing the monomers to be added alone or in emulsion at a variable speed, between 1.45 and 145 ml / h.
  • the kinetics are followed by regular samples, and the reaction stopped when the conversion rate reaches 100%, or when it stabilizes (for incomplete reactions).
  • the latex is bubbled with nitrogen for half an hour and cooled to room temperature.
  • the coagulum is separated from the latex by filtration through a sieve. 1.3 / Determination of the conversion rate
  • the conversion rate Te is defined by the ratio between the real solid rate of the latex and that of the theoretical latex, corrected by the initial solid rate, according to the following formula:
  • Ts real solid content, determined by dry extract
  • TSJ initial solid level, due to the initiator, to the surfactants and to the possible buffer
  • the particle size is determined by quasi-elastic light scattering, on a Coulter N4 + type device from the company Coultronics.
  • the slightly diluted latex (20 to 30% solid content) is introduced into a flexible cellulose dialysis tube with a cutoff threshold of 50,000 Da (Spectra / Pore 7), then immersed in distilled water.
  • Dilution is necessary due to the difference in osmotic pressure on either side of the membrane.
  • the exchange water is renewed every twelve hours at the start and then every day until a constant conductivity of this water is obtained.
  • the overall purification operation can thus last up to 15 or 20 days, in particular for latexes whose conversion has not been complete.
  • Latexes were synthesized according to the "modified" batch-shot process, that is to say that the addition of the rest of the monomer, including the acid, is done continuously and not in one times after approximately 90% conversion of the majority of the monomers introduced in batch.
  • the seed is composed of styrene and butyl acrylate in proportion 41/59. It consists of almost 68% of all the monomers.
  • the latex L 4 below was synthesized by adding the functionalized monomer (AMA) at a speed of 20 ml / h, carrying out the addition 1 hour after the start of the polymerization. Its characteristics are given in table 3 below:
  • Latex L 4 is subjected to a purification by dialysis as indicated in Example 1.
  • the penetration of water inside the film can contribute to the diffusion of lead, and, by accumulation at the film / substrate interface, is likely to generate adhesion defects and problems of delamination of the coating.
  • a styrene / butyl acrylate / acrylic acid latex was used
  • the film was prepared on a Teflon® plate using a film puller leading to a wet thickness of 500 ⁇ m.
  • the solid content of the latex applied is between 30 and 50% depending on the viscosity of the latter. After drying, the film thickness is around 200 ⁇ m.
  • the drying takes place in two stages, the latex deposited on Teflon® being first left at 20 ° C for 20 minutes, then placed at 50 ° C for one hour.
  • the film is then left at 20 ° C. for three hours in order to simulate the implementation on pipe in real medium in the interval of a day of 10 hours. It is then cut into 9 cm 2 squares, in six copies.
  • the water sensitivity of the films is evaluated by gravimetry following continuous immersion in water at 20 ° C, on the films free of any support.
  • the exposed surface is therefore twice the real surface of films deposited on a substrate.
  • the graph M (t) / Mo (expressed as a percentage) ⁇ f (t) (expressed in h) is represented in FIG. 1.
  • the following symbols are used: - * - represents the latex dialysis -m- represents the latex not dialysis
  • the pipeline is completely filled with a 3N phosphoric acid solution. After a contact time of 10 to 15 minutes, the pipe is drained, rinsed and dried at room temperature.
  • the latex coating is done in the same way, without the need to allow the latex to stagnate.
  • the hose is filled, then drained without waiting. No excess latex should remain in the hose.
  • the ends of the tube are also coated with latex to avoid inadvertent contact of lead with water.
  • This first layer is allowed to dry for one hour at 50 ° C, in a vertical position in a thermostatically controlled enclosure.
  • the second coating is carried out in the same way, after a cooling time of approximately 5 to 10 minutes.
  • the ends are protected and insulated by dipping them in hot paraffin over a height of about 5 mm.
  • the pipe section After the complete coating step (depending on the number of layers) the pipe section is left at 20 ° C for 3 hours. It is first closed with parafilm® to prevent evaporation, and placed in an enclosure thermostatically controlled at 30 ° C. For all filling operations, one end of the tube is closed with several layers of parafilm®.
  • a preliminary test consists of a 2-day stagnation of the water introduced into these sections of pipeline. Depending on the lead concentration measured, the pipe is rinsed and filled again with distilled water. This second stagnation lasts 15 days.
  • the lead concentration is measured, after stirring the assembly at the end of the stagnation period, using a SCANNING SA-1000 analyzer (Palintest Instruments) on 5 ml samples.

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  • Life Sciences & Earth Sciences (AREA)
  • Wood Science & Technology (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Mechanical Engineering (AREA)
  • Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
  • Application Of Or Painting With Fluid Materials (AREA)

Abstract

The invention relates to a method of coating the inner wall of a pipe with a protective film, consisting in forming said protective film from at least one latex. The invention also relates to the use of at least one latex in order to form a film that is intended to coat the inner wall of a pipe.

Description

Procédé de revêtement de la paroi interne d'une canalisation par un film de latexMethod of coating the internal wall of a pipe with a latex film
La présente invention concerne un procédé de revêtement de la paroi interne d'une canalisation par un film protecteur comprenant la formation de ce film à partir d'au moins un latex.The present invention relates to a method of coating the internal wall of a pipe with a protective film comprising the formation of this film from at least one latex.
L'invention concerne également l'utilisation de latex pour former un film destiné au revêtement de la paroi interne d'une canalisation pour réduire ou supprimer le relargage d'un ou plusieurs constituants du matériau de ladite canalisation dans un liquide conduit par celle-ci.The invention also relates to the use of latex to form a film intended for coating the internal wall of a pipe to reduce or eliminate the release of one or more constituents of the material of said pipe in a liquid led by the latter. .
Une canalisation, un tuyau ou une portion de tuyau dont la paroi interne est revêtue d'un film obtenu à partir d'au moins un latex représente des objets ultérieurs de l'invention. Le procédé selon l'invention est notamment applicable à une canalisation d'alimentation en eau, en particulier en eau potable, de préférence ayant une température inférieure à environ 30°C, en particulier inférieure ou égale à environ 20°C.A pipe, a pipe or a portion of pipe whose inner wall is coated with a film obtained from at least one latex represents further objects of the invention. The method according to the invention is particularly applicable to a water supply pipe, in particular drinking water, preferably having a temperature below about 30 ° C, in particular less than or equal to about 20 ° C.
Le procédé selon l'invention trouve une application particulièrement avantageuse pour le revêtement de canalisations métalliques, en particulier les canalisations en plomb.The method according to the invention finds a particularly advantageous application for the coating of metal pipes, in particular lead pipes.
En effet, la décision récente de l'Union Européenne et de la France de s'aligner sur les recommandations de l'Organisation Mondiale de la Santé (OMS) en diminuant la teneur limite acceptable en plomb dans l'eau potable de 50 à 10 μg/l d'ici l'année 2013 impose aux entreprises gestionnaires des réseaux de distribution de trouver rapidement une solution qui satisfasse à la fois les normes et les particuliers.Indeed, the recent decision of the European Union and France to align with the recommendations of the World Health Organization (WHO) by reducing the acceptable limit content of lead in drinking water from 50 to 10 μg / l by the year 2013 requires companies managing distribution networks to quickly find a solution that meets both standards and individuals.
L'eau en sortie de station d'approvisionnement étant toujours en dessous de cette limite de 10 μg/l mais se charge en élément plomb en passant dans les conduites anciennes.The water leaving the supply station is always below this limit of 10 μg / l but is loaded with lead element by passing through the old pipes.
Dans les habitations, la solution unique, pour le moment, reste souvent de casser les cloisons, murs et aménagements de l'habitation pour accéder aux tuyaux.In homes, the only solution, for the moment, often remains to break the partitions, walls and fittings of the home to access the pipes.
Il convient donc de mettre au point une méthode de rénovation non destructive des canalisations.It is therefore advisable to develop a method of non-destructive renovation of pipes.
Le film doit présenter les caractéristiques suivantes pour correspondre au besoin identifié : imperméabilité à l'eau et au plomb, adhésion sur plomb usagé, c'est-à-dire non traité et ayant subi les attaques de l'eau potable, ou éventuellement décapé, souplesse suffisante pour supporter des torsions de tuyau, - durée d'efficacité supérieure à 10 ans.The film must have the following characteristics to correspond to the identified need: impermeability to water and lead, adhesion to used lead, that is to say untreated and having been attacked by drinking water, or possibly stripped , sufficient flexibility to withstand hose twists, - service life greater than 10 years.
Le polymère qui le constitue doit répondre aux exigences suivantes: être élaboré à partir de composés chimiques (monomères, amorceurs, additifs) entrant dans les normes "qualité alimentaire", dans le cas du revêtement de la paroi interne d'une canalisation destinée à l'alimentation en eau potable, présenter une bonne résistance chimique à l'eau et au chlore.The polymer which constitutes it must meet the following requirements: be made from chemical compounds (monomers, initiators, additives) falling within the "food quality" standards, in the case of coating the internal wall of a pipe intended for the drinking water supply, have good chemical resistance to water and chlorine.
En outre, le procédé doit être le plus simple possible pour limiter les opérations successives accroissant le coût de l'opération, convenir pour l'application dans des tuyaux à la fois de petits et gros diamètres, ainsi que sur un réseau comportant raccords et embranchements, et permettre l'enduction de la canalisation dans un délai court, afin de limiter au maximum la durée de la coupure d'eau.In addition, the process must be as simple as possible to limit successive operations increasing the cost of the operation, suitable for application in pipes of both small and large diameters, as well as on a network comprising fittings and branches. , and allow the coating of the pipeline in a short time, in order to limit the duration of the water cut as much as possible.
De plus, le film doit être formé dans des conditions de températures proches de l'ambiante.In addition, the film must be formed under conditions of temperatures close to ambient.
Le chemisage par un polymère est déjà une technique employée dans le domaine des revêtements internes de canalisation.Lining with a polymer is already a technique used in the field of internal pipe coatings.
Ainsi, le brevet DE 4012605 décrit un procédé de réparation et le gainage de canalisation d'eaux usées, à usage public ou industriel. Le revêtement est constitué d'une emulsion bitumineuse contenant une dispersion de poly(chlorobutadiène) et éventuellement d'autres polymères, tels que résines naturelles, poly(vinyle propionate ou acétate) ou polyvinyl alcool. La dispersion est appliquée en spray et le séchage est assuré par un courant d'air chaud.Thus, patent DE 4012605 describes a process for repairing and sheathing of waste water pipes, for public or industrial use. The coating consists of a bituminous emulsion containing a dispersion of poly (chlorobutadiene) and possibly other polymers, such as natural resins, poly (vinyl propionate or acetate) or polyvinyl alcohol. The dispersion is applied as a spray and drying is ensured by a current of hot air.
Dans le procédé de la demande EP 0 299 134, on fait circuler, après un nettoyage abrasif, une résine époxy liquide dans les canalisations, en allant des plus petits vers les plus gros diamètres. La quantité de résine suffisante, calculée pour une canalisation ou un étage, est poussé à l'intérieur de la canalisation par de l'air comprimé. Le chauffage de la résine est assuré par un courant d'air chaud.In the process of application EP 0 299 134, a liquid epoxy resin is circulated, after an abrasive cleaning, in the pipes, going from the smallest to the largest diameters. The sufficient quantity of resin, calculated for a pipeline or a stage, is pushed inside the pipeline by compressed air. The resin is heated by a stream of hot air.
Le brevet français FR 2 728 652 concerne un procédé de revêtement intérieur de canalisation de faible diamètre dans lequel une résine époxy est poussée par un tampon souple de diamètre légèrement inférieur à celui de la canalisation. Le déplacement régulier de l'ensemble résine + tampon est assuré par une faible différence de pression.French patent FR 2 728 652 relates to a process for the internal coating of small diameter pipes in which an epoxy resin is pushed by a flexible pad with a diameter slightly smaller than that of the pipes. The regular movement of the resin + buffer assembly is ensured by a small pressure difference.
La demande GB 1 322 122 concerne une méthode pour colmater les fuites dans des tuyaux, notamment par l'application de latex naturel ou synthétique.Application GB 1 322 122 relates to a method for sealing leaks in pipes, in particular by applying natural or synthetic latex.
Toutefois, ces méthodes ne permettaient pas de s'affranchir d'un certain nombre de contraintes techniques, telles que par exemple la nécessité de démonter des robinets d'alimentation et de poser des vannes provisoires, ou de chauffer la canalisation après vidange du trop-plein de latex.However, these methods did not make it possible to overcome a certain number of technical constraints, such as for example the need to dismantle supply taps and to install temporary valves, or to heat the pipe after draining of the overflow. full of latex.
De plus, les résines utilisées ont en général une "pot-life", c'est-à- dire une durée de vie dans le récipient d'utilisation, de courte durée, ce qui rend leur utilisation peu aisée.In addition, the resins used generally have a "pot-life", that is to say a lifetime in the container of use, of short duration, which makes their use not very easy.
On a maintenant trouvé que l'utilisation d'au moins un latex pour former un film revêtant la paroi interne d'une canalisation permet de s'affranchir de ces contraintes, tout en répondant aux exigences officielles en matière de matériau organique pouvant être utilisé dans des installations fixes de distribution, de traitement et de production d'eau, notamment d'eau destinée à la consommation, à savoir notamment la limite de migration de la part du matériau fini, la qualité organoleptique de l'eau, l'inertie bactérienne (pas de contribution à la formation d'un biofilm) et l'absence de cytotoxicité. Selon l'invention, le latex utilisé pour former le film est tel que, lorsqu'il est dilué à 20% d'extrait sec dans de l'eau déminéralisée, sa conductivité est inférieure à 1 ,3 mS/cm.It has now been found that the use of at least one latex to form a film coating the internal wall of a pipe overcomes these constraints, while meeting official requirements for organic material that can be used in fixed installations for the distribution, treatment and production of water, in particular water intended for consumption, namely in particular the migration limit on the part of the finished material, the organoleptic quality of the water, the bacterial inertia (no contribution to the formation of a biofilm) and the absence of cytotoxicity. According to the invention, the latex used to form the film is such that, when it is diluted to 20% of dry extract in demineralized water, its conductivity is less than 1.3 mS / cm.
En particulier, la conductivité dudit latex dilué à 20% d'extrait sec dans de l'eau déminéralisée sera inférieure à 1mS/cm, de préférence inférieure à 0,9 mS/cm.In particular, the conductivity of said latex diluted to 20% of dry extract in demineralized water will be less than 1 mS / cm, preferably less than 0.9 mS / cm.
Par " latex dilué à 20% d'extrait sec dans de l'eau déminéralisée ", on entend un latex ramené à un taux de solide de 20% par ajout d'eau déminéralisée . La conductivité est mesurée à l'aide d'un conductimètre à une température de 20°C.The term "latex diluted to 20% of dry extract in demineralized water" means a latex reduced to a solid level of 20% by adding demineralized water. Conductivity is measured using a conductivity meter at a temperature of 20 ° C.
Par "latex", on entend dans la présente description une suspension de particules de polymère générées in situ dans une phase continue constituée par un solvant aqueux, de préférence de l'eau ou un mélange eau/cosolvant, par exemple un alcool.By "latex" in the present description is meant a suspension of polymer particles generated in situ in a continuous phase consisting of an aqueous solvent, preferably water or a water / cosolvent mixture, for example an alcohol.
De préférence, le diamètre des particules est de l'ordre de 10 nm à 5 μm, en particulier de 100 à 300 nm.Preferably, the particle diameter is of the order of 10 nm to 5 μm, in particular from 100 to 300 nm.
Pour former le latex, on utilise plus spécifiquement selon l'invention comme monomère éthyléniquement insaturé des monomères choisis parmi le styrène et ses dérivés, le butadiène, le chloroprène, les estersTo form the latex, the monomers chosen from styrene and its derivatives, butadiene, chloroprene and esters are used more specifically according to the invention as ethylenically unsaturated monomer to form the latex.
(méth)acryliques, les esters vinyliques, les nitriles vinyliques, lesdits monomères sont polymérisés ou copolymérisés.(meth) acrylic, vinyl esters, vinyl nitriles, said monomers are polymerized or copolymerized.
Par esters (méth)acryliques, on désigne les esters de l'acide acrylique ou de l'acide méthacrylique avec les alcools en Cι-C12 hydrogénés ou fluorés, de préférence en C-i-Cβ. Parmi les composés de ce type, on peut citer : l'acrylate de méthyle, l'acrylate d'éthyle, l'acrylate de propyle, l'acrylate de n- butyle, l'acrylate d'isobutyle, l'acrylate de 2-éthylhexyle, l'acrylate de t-butyle, le méthacrylate de méthyle, le méthacrylate d'éthyle, le méthacrylate de n-butyle, le méthacrylate d'isobutyle. Les nitriles vinyliques incluent plus particulièrement ceux enBy (meth) acrylic esters is meant the esters of acrylic acid or methacrylic acid with hydrogenated or fluorinated Cι-C 12 alcohols, preferably Ci-Cβ. Among the compounds of this type, there may be mentioned: methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, 2-acrylate -ethylhexyl, t-butyl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isobutyl methacrylate. Vinyl nitriles more particularly include those
C3-Cι2, comme en particulier l'acrylonitrile et le méthacrylonitrile.C 3 -Cι 2 , such as in particular acrylonitrile and methacrylonitrile.
Il est à noter que le styrène peut être remplacé en totalité ou en partie par des dérivés tels que l'alphaméthylstyrène ou le vinyltoluène.It should be noted that the styrene can be replaced in whole or in partly by derivatives such as alphamethylstyrene or vinyltoluene.
Les autres monomères éthyléniquement insaturés, utilisables seuls ou en mélanges, ou copolymérisables avec les monomères ci-dessus sont notamment : - les esters vinyliques d'acides carboxyliques comme l'acétate de vinyle, le versatate de vinyle, le propionate de vinyle, les halogénures de vinyle, les acides mono- et di- carboxyliques insaturés éthyléniques comme l'acide acrylique, l'acide méthacrylique, l'acide itaconique, l'acide maléique, l'acide fumarique et les mono-alkylesters des acides dicarboxyliques du type cité avec les alcanols de préférence en Cι-C et leurs dérivés N-substitués, les amides des acides carboxyliques insaturés comme l'acrylamide, le méthacrylamide, le N-méthylolacrylamide ou méthacrylamide, les N-alkylacrylamides, - les monomères éthyléniques comportant un groupe acide sulfonique et ses sels alcalins ou d'ammonium par exemple l'acide vinylsulfonique, l'acide vinyl- benzène sulfonique, l'acide alpha-acrylamido méthylpropane-sulfonique, le 2-sulfoéthylène-méthacrylate, les amides de la vinylamine, notamment le vinylformamide ou le vinylacétamide, les monomères éthyléniques insaturés comportant un groupe amino secondaire, tertiaire ou quaternaire, ou un groupe hétérocyclique contenant de l'azote tel que par exemple les vinylpyridines, le vinylimidazole, les (méth)acrylates d'aminoalkyle et les (méth)acrylamides d'aminoalkyle comme le diméthylaminoéthyl-acrylate ou -méthacrylate, le ditertiobutylaminoéthyl- acrylate ou -méthacrylate, le diméthylamino méthyl-acrylamide ou -méthacrylamide. Il est de même possible d'utiliser des monomères zwitterioniques comme par exemple l'acrylate de sulfopropyl (diméthyl)aminopropyle. - des monomères permettant une réticulation lors de la mise en oeuvre, par exemple par voie chimique, thermique ou photochimique, tels que le méthacrylate de glycidyle ou l'acrylate de dihydrodicyclopentadienyle. Lorsque ladite canalisation est destinée à l'alimentation en eau potable, ledit latex est formé de préférence par polymérisation ou copolymérisation de monomères de qualité alimentaire. Des listes de monomères agrées sont disponibles pays par pays. Des monomères de qualité alimentaire avantageux sont choisis parmi les esters méthacryliques, notamment l'acrylate de n-butyle, l'acide méthacrylique et ses dérivés; le styrène et ses dérivés.The other ethylenically unsaturated monomers which can be used alone or in mixtures or which can be copolymerized with the above monomers are in particular: - vinyl esters of carboxylic acids such as vinyl acetate, vinyl versatate, vinyl propionate, halides vinyl, ethylenic unsaturated mono- and dicarboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid and the mono-alkyl esters of dicarboxylic acids of the type mentioned with alkanols preferably Cι-C and their N-substituted derivatives, amides of unsaturated carboxylic acids such as acrylamide, methacrylamide, N-methylolacrylamide or methacrylamide, N-alkylacrylamides, - ethylenic monomers comprising a sulfonic acid group and its alkali or ammonium salts, for example vinylsulfonic acid, vinylbenzene sulfonic acid, alpha-acrylamido methylpropane-sulfoni acid that, 2-sulfoethylene methacrylate, amides of vinylamine, in particular vinylformamide or vinylacetamide, ethylenic unsaturated monomers comprising a secondary, tertiary or quaternary amino group, or a heterocyclic group containing nitrogen such as for example the vinylpyridines, vinylimidazole, aminoalkyl (meth) acrylates and aminoalkyl (meth) acrylamides such as dimethylaminoethyl acrylate or -methacrylate, ditertiobutylaminoethylacrylate or -methacrylate, dimethylamino methylacrylamide or -methacrylamide. It is likewise possible to use zwitterionic monomers such as for example sulfopropyl (dimethyl) aminopropyl acrylate. - Monomers allowing crosslinking during processing, for example by chemical, thermal or photochemical means, such as glycidyl methacrylate or dihydrodicyclopentadienyl acrylate. When said pipe is intended for drinking water supply, said latex is preferably formed by polymerization or copolymerization of food grade monomers. Lists of approved monomers are available country by country. Advantageous food grade monomers are chosen from methacrylic esters, in particular n-butyl acrylate, methacrylic acid and its derivatives; styrene and its derivatives.
Selon un aspect préféré de l'invention, ledit latex comprend un polymère ou un copolymère ayant une température formation de film comprise entre 0°C et 20°C.According to a preferred aspect of the invention, said latex comprises a polymer or a copolymer having a film-forming temperature of between 0 ° C and 20 ° C.
Selon un aspect préféré de l'invention, ledit latex comprend un polymère ou un copolymère ayant une température de transition vitreuse (Tg) inférieure à 20°C, et de manière encore plus préférentielle d'une température de transition vitreuse comprise entre 0°C et 10°C. Le latex utilisable aux fins de l'invention présente avantageusement un taux de solides élevé, en particulier supérieur ou égal à 20%, notamment de 30 à 50%. Une autre propriété avantageuse dudit latex est de présenter un taux de coagulum faible, notamment inférieur à 10%, de préférence inférieur à 0,1%. Le taux de solides et le taux de coagulum sont déterminés comme indiqué dans l'exemple 1.According to a preferred aspect of the invention, said latex comprises a polymer or a copolymer having a glass transition temperature (T g ) of less than 20 ° C, and even more preferably of a glass transition temperature of between 0 ° C and 10 ° C. The latex which can be used for the purposes of the invention advantageously has a high level of solids, in particular greater than or equal to 20%, in particular from 30 to 50%. Another advantageous property of said latex is to have a low level of coagulum, in particular less than 10%, preferably less than 0.1%. The level of solids and the level of coagulum are determined as indicated in Example 1.
De préférence, le latex, préalablement à son utilisation pour former un film, est soumis à un traitement de purification destiné à diminuer la concentration en constituants hydrosolubles dudit latex.Preferably, the latex, before its use to form a film, is subjected to a purification treatment intended to reduce the concentration of water-soluble constituents of said latex.
Par "constituant hydrosoluble", on entend dans la présente description des monomères résiduels restant dans le solvant après polymérisation, les oligomères comprenant environ 2 à 10 unités monomériques, les résidus de sels provenant des amorceurs de polymérisation, les ions provenant du tampon de polymérisation et, lorsque des agents tensio- actifs sont utilisés lors de la formation du latex, ceux d'entre eux qui ne sont pas impliqués dans la stabilisation des particules de polymère, ainsi que tout autre constituant qui reste en solution dans la phase continue à l'issue de la formation du latex. Ce traitement de purification est avantageusement mis en oeuvre par dialyse et/ou ultrafiltration. Ledit latex, à l'issue d'un tel traitement de purification, présente une concentration en constituants hydrosolubles inférieure à celle du latex obtenu à l'issue de la polymérisation ou de la copolymérisation. Selon un aspect avantageux, le procédé de revêtement de la paroi interne d'une canalisation comprend les étapes suivantes : on remplit une canalisation à l'aide d'un latex, on vidange ladite canalisation de manière à laisser s'écouler le trop-plein de latex et à former une couche de latex sur la paroi interne de la canalisation, - on chauffe la couche de latex de manière à former le film protecteur sur la paroi interne de ladite canalisation.By "water-soluble constituent" is meant in the present description the residual monomers remaining in the solvent after polymerization, the oligomers comprising approximately 2 to 10 monomeric units, the salt residues originating from the polymerization initiators, the ions originating from the polymerization buffer and , when surface-active agents are used during the formation of the latex, those of them which are not involved in the stabilization of the polymer particles, as well as any other constituent which remains in solution in the continuous phase at the resulting from the formation of latex. This purification treatment is advantageously carried out by dialysis and / or ultrafiltration. Said latex, at the end of such a purification treatment, has a lower concentration of water-soluble constituents than that of the latex obtained at the end of the polymerization or of the copolymerization. According to an advantageous aspect, the method of coating the internal wall of a pipe comprises the following steps: filling a pipe with latex, draining said pipe so as to allow the overflow to flow latex and to form a layer of latex on the internal wall of the pipe, - the latex layer is heated so as to form the protective film on the internal wall of said pipe.
Ce procédé ne nécessite aucun démontage des canalisations. De plus, le latex a une durée de vie de plusieurs heures, rendant son utilisation particulièrement aisée. Le remplissage de la canalisation est par exemple effectué à température ambiante.This process does not require any disassembly of the pipes. In addition, the latex has a lifespan of several hours, making its use particularly easy. The filling of the pipe is for example carried out at room temperature.
Le chauffage de la couche de latex de manière à former le film protecteur peut être effectué à une température de l'ordre de 30 à 80°C.The heating of the latex layer so as to form the protective film can be carried out at a temperature of the order of 30 to 80 ° C.
La paroi interne de la canalisation peut être revêtue de plusieurs films de latex superposés, en particulier de deux films de latex superposés.The internal wall of the pipe can be coated with several superimposed latex films, in particular with two superimposed latex films.
Dans ce cas, chacun des films de latex est appliqué après séchage du film précédent, chacun des films a une épaisseur d'environ 50 à 500 μm, de préférence 100 à 250 μm.In this case, each of the latex films is applied after drying of the preceding film, each of the films has a thickness of approximately 50 to 500 μm, preferably 100 to 250 μm.
Le remplissage de la canalisation peut être avantageusement effectué sous pression, par exemple une pression de 2 à 50 Pa.The filling of the pipe can advantageously be carried out under pressure, for example a pressure of 2 to 50 Pa.
Le revêtement de la paroi interne de la canalisation peut être effectué sur la canalisation telle quelle, sans traitement préalable de celle-ci.The lining of the internal wall of the pipe can be carried out on the pipe as it is, without prior treatment of the latter.
Avantageusement, lorsque ladite canalisation est en plomb, un traitement préalable au moyen d'un acide peut être effectué. On utilisera avantageusement l'acide orthophosphorique, en particulier à la molarité 3N. L'invention concerne également un tuyau ou une portion de tuyau revêtu d'un film obtenu à partir d'au moins un latex, dont le revêtement est susceptible d'être effectué par le procédé décrit plus haut.Advantageously, when the said pipe is made of lead, a preliminary treatment with an acid can be carried out. Advantageously, orthophosphoric acid will be used, in particular with 3N molarity. The invention also relates to a pipe or a portion of pipe coated with a film obtained from at least one latex, the coating of which can be carried out by the method described above.
Les tuyaux ou portions de tuyaux ainsi revêtus présentent des propriétés de résistance à la torsion améliorées par rapport à des tuyaux revêtus de résines, telles que certaines résines époxy, du fait des propriétés élastiques du latex.The pipes or pipe portions thus coated have improved torsional strength properties compared to pipes coated with resins, such as certain epoxy resins, due to the elastic properties of latex.
Le latex susceptible d'être utilisé aux fins de l'invention peut être obtenu par des procédés usuels. Les réactifs mis en œuvre pour l'obtention d'un latex utilisable aux fins de l'invention sont ceux utilisés de manière classique dans la technique de polymérisation en emulsion. Celle-ci met en jeu quatre constituants principaux : le milieu de dispersion (ou phase continue), le ou les agent(s) tensîoactif(s) ; classiquement à hauteur de 0,01 à 10% en masse par rapport au(x) monomère(s), suivant le type de stabilisation, le(s) monomère(s), l'amorceur, soluble dans le milieu dispersant, généralement à hauteur de 0,5 à 2% en masse par rapport au(x) monomère(s).The latex capable of being used for the purposes of the invention can be obtained by conventional methods. The reagents used to obtain a latex which can be used for the purposes of the invention are those used conventionally in the emulsion polymerization technique. This involves four main constituents: the dispersion medium (or continuous phase), the surfactant (s); conventionally up to 0.01 to 10% by mass relative to the monomer (s), depending on the type of stabilization, the monomer (s), the initiator, soluble in the dispersing medium, generally at height of 0.5 to 2% by mass relative to the monomer (s).
D'autres constituants peuvent intervenir pour améliorer les propriétés du latex final, et/ou assurer un meilleur contrôle de la réaction de certains systèmes.Other constituents can intervene to improve the properties of the final latex, and / or ensure better control of the reaction of certain systems.
On peut citer notamment des agents de transferts de chaîne, des agents tampon pour maîtriser le pH du milieu, et des agents chélatants.Mention may in particular be made of chain transfer agents, buffering agents for controlling the pH of the medium, and chelating agents.
Le milieu de dispersion est constitué généralement par de l'eau ou un mélange eau/cosolvant tel qu'un alcool, en particulier le méthanol, dans laquelle sont dispersés ou dissous les constituants.The dispersion medium generally consists of water or a water / cosolvent mixture such as an alcohol, in particular methanol, in which the constituents are dispersed or dissolved.
Lors de la mise en œuvre de la synthèse, l'agent tensioactif est d'abord dissous dans la phase aqueuse, conduisant à la formation d'une solution micellaire, si la concentration en tensioactif est suffisante (concentration micellaire critique). On utilisera de préférence des agents tensioactifs ioniques, notamment des agents tensioactifs anioniques tels que les alkylsulfonates de sodium.During the implementation of the synthesis, the surfactant is first dissolved in the aqueous phase, leading to the formation of a micellar solution, if the surfactant concentration is sufficient (critical micellar concentration). Preferably ionic surfactants will be used, especially anionic surfactants such as sodium alkylsulfonates.
On peut également utiliser des agents tensioactifs non-ioniques, ainsi que des agents tensioactifs macromoléculaires constitués de copolymères à blocs comportant une séquence à base de poly(oxyde d'éthylène) (POE), liée à une séquence hydrophobe composée d'une chaîne polymère, tel que poly(styrène) (PS) ou poly(méthacrylate de méthyle) (PMMA). La partie hydrophile peut également être, au lieu d'une chaîne de POE, une séquence hydrophile anionique ou cationique.Non-ionic surfactants can also be used, as well as macromolecular surfactants consisting of block copolymers comprising a block based on poly (ethylene oxide) (POE), linked to a hydrophobic block composed of a polymer chain. , such as poly (styrene) (PS) or poly (methyl methacrylate) (PMMA). The hydrophilic part can also be, instead of a POE chain, an anionic or cationic hydrophilic sequence.
Les monomères sont ajoutés à cette solution micellaire, et stabilisés grâce à l'agent tensioactif.The monomers are added to this micellar solution, and stabilized using the surfactant.
Les latex utilisables aux fins de l'invention peuvent être issus de la copolymérisation de plusieurs monomères, afin de bénéficier d'une large palette de propriétés modulables. Ceux-ci peuvent notamment être plus au moins hydrosolubles.The latexes which can be used for the purposes of the invention can be derived from the copolymerization of several monomers, in order to benefit from a wide range of modular properties. These can in particular be more or less water-soluble.
Les amorceurs sont généralement issus de la catégorie des peroxydes, notamment inorganiques (H2O2, K2S2Oδ).The initiators generally come from the category of peroxides, in particular inorganic (H 2 O 2 , K 2 S 2 O δ ).
L'amorceur le plus utilisé est le persulfate de potassium ou de sodium. Il peut être associé à un couple rédox tel que (Fe2+/Fe3+) afin de pouvoir abaisser la température de polymérisation.The most widely used initiator is potassium or sodium persulfate. It can be combined with a redox couple such as (Fe 2+ / Fe 3+ ) in order to be able to lower the polymerization temperature.
Les tampons permettent de conserver le milieu de polymérisation à un pH constant tout au long de la réaction. La régulation du pH permet également d'éviter la formation de certaines associations ioniques qui empêcheraient de mener la réaction à terme.The buffers allow the polymerization medium to be kept at a constant pH throughout the reaction. Regulation of the pH also makes it possible to avoid the formation of certain ionic associations which would prevent the completion of the reaction.
Les agents de transfert de chaîne sont utilisés pour contrôler la masse moléculaire moyenne du polymère et éviter les réticulations. On utilisera par exemple un alkyle-mercaptant de formule générale R-SH.Chain transfer agents are used to control the average molecular weight of the polymer and to prevent crosslinking. For example, an alkyl mercaptant of general formula R-SH will be used.
Les agents chélatants peuvent également s'avérer nécessaires pour rendre inactifs certains ions métalliques susceptibles de perturber la polymérisation et sont choisis en fonction du type d'ion et du pH du milieu. Alternativement, il est possible de synthétiser des latex en l'absence d'agents tensioactifs, notamment ceux contenant des monomères portant au moins une fonction acide carboxylique, en adaptant les paramètres de la réaction de polymérisation, à savoir la vitesse d'agitation, le pourcentage massique en monomère portant au moins une fonction acide carboxylique par rapport à la quantité de monomères totale et le pourcentage massique en amorceur par rapport la quantité de monomères totale, de manière à obtenir des particules de latex de taille appropriée.Chelating agents may also prove to be necessary to render inactive certain metal ions liable to disturb the polymerization and are chosen according to the type of ion and the pH of the medium. Alternatively, it is possible to synthesize latexes in the absence of surfactants, in particular those containing monomers carrying at least one carboxylic acid function, by adapting the parameters of the polymerization reaction, namely the speed of agitation, the mass percentage of monomer carrying at least one carboxylic acid function relative to the total quantity of monomers and the mass percentage of initiator relative to the total quantity of monomers, so as to obtain latex particles of appropriate size.
Les latex utilisables aux fins de l'invention peuvent être fonctionnalisés, c'est à dire que des fonctions réactives ou ionisables sont liées de manière covalente à la surface des particules.The latexes which can be used for the purposes of the invention can be functionalized, that is to say that reactive or ionizable functions are covalently linked to the surface of the particles.
Cette fonctionnalisation peut être réalisée : par incorporation de groupes chimiques réactifs portés par l'amorceur radicalaire (sulfate ou carboxylate sont les plus fréquents), - par stabilisation des agents tensioactifs ioniques ou non ioniques de type "surfmers", par modification chimique post-polymérisation, ou par incorporation de monomères fonctionnels dans les chaînes par copolymérisation. On utilisera avantageusement la fonctionnalisation par des monomères carboxyliques, tels que les acides acryliques et/ou méthacryliques pour améliorer l'adhésion et favoriser les interactions des latex avec les substrats, notamment métalliques.This functionalization can be carried out: by incorporation of reactive chemical groups carried by the radical initiator (sulphate or carboxylate are the most frequent), - by stabilization of ionic or non-ionic surfactants of the "surfmers" type, by post-polymerization chemical modification , or by incorporation of functional monomers in the chains by copolymerization. Advantageously, functionalization will be used with carboxylic monomers, such as acrylic and / or methacrylic acids to improve the adhesion and promote the interactions of latexes with substrates, in particular metallic.
La synthèse du latex peut être réalisée en réacteur fermé, dite en mode "batch", dans laquelle tous les composants (eau, tensioactif, monomère, tampon éventuel) nécessaires à la synthèse sont introduits dans le réacteur avant d'amorcer la réaction, celle-ci étant conduite à température et agitation données.The synthesis of the latex can be carried out in a closed reactor, known as "batch" mode, in which all the components (water, surfactant, monomer, optional buffer) necessary for the synthesis are introduced into the reactor before initiating the reaction, that this being carried out at given temperature and stirring.
On peut également mettre en œuvre une synthèse en plusieurs étapes, et notamment la polymérisation dite "ensemencée" dans laquelle la synthèse débute par la polymérisation d'une "semence" composée d'une partie des monomères. Pour l'addition de la seconde partie des monomères, soit en batch, soit en semi-continu, on se place dans la période où le nombre de particules est constant, l'amorceur étant ajouté en parallèle.It is also possible to carry out a synthesis in several stages, and in particular the so-called "seeded" polymerization in which the synthesis begins with the polymerization of a "seed" composed of a part of the monomers. For the addition of the second part of the monomers, either in batch, or semi-continuous, we place ourselves in the period where the number of particles is constant, the initiator being added in parallel.
On peut également utiliser aux fins de l'invention un latex disponible commercialement. De préférence, ledit latex sera soumis à un traitement de purification par dialyse et/ou ultrafiltration préalablement à son utilisation pour l'enduction de la paroi interne d'une canalisation.A commercially available latex can also be used for the purposes of the invention. Preferably, said latex will be subjected to a purification treatment by dialysis and / or ultrafiltration prior to its use for coating the internal wall of a pipe.
Le latex dilué par exemple à 20% est introduit dans un bac de recirculation et on le fait passer dans un module d'ultrafiltration à une vitesse comprise entre 1 à 5 m/s à température ambiante et on applique une pression comprise entre 1 et 5 bars.The latex diluted for example to 20% is introduced into a recirculation tank and it is passed through an ultrafiltration module at a speed between 1 to 5 m / s at room temperature and a pressure between 1 and 5 is applied. bars.
Le module d'ultrafiltration peut être utilisé avec des membranes minérales ou organiques, avec un seuil de coupure (taille des pores) adapté au latex utilisé. Le latex est purifié par diafiltration jusqu'à obtenir la pureté requise.The ultrafiltration module can be used with mineral or organic membranes, with a cutoff threshold (pore size) adapted to the latex used. The latex is purified by diafiltration until the required purity is obtained.
On considère que le latex est suffisamment purifié à partir du moment où la conductivité se rapproche du seuil où elle est constante.It is considered that the latex is sufficiently purified from the moment when the conductivity approaches the threshold where it is constant.
Cette valeur dépend des latex utilisés et de leur état de dilution initiale.This value depends on the latex used and its initial dilution state.
On peut également utiliser d'autres techniques de purification, notamment des techniques d'absorption sur résine.Other purification techniques can also be used, in particular absorption techniques on resin.
A titre d'exemple, pour un latex dilué à environ 20% dans de l'eau déminéralisée, on considère que le latex est suffisamment purifié lorsque sa conductivité est inférieure à 1 ,3 mS/cm, de préférence inférieure à 1 mS/cm, et de manière encore plus préférentielle inférieure à 0,9 mS/cm.By way of example, for a latex diluted to approximately 20% in demineralized water, it is considered that the latex is sufficiently purified when its conductivity is less than 1.3 mS / cm, preferably less than 1 mS / cm , and even more preferably less than 0.9 mS / cm.
L'invention est illustrée par les exemples ci-dessous :The invention is illustrated by the examples below:
Exemple 1 : Synthèse de latex de terpolymère en mode "batch" 1.1/ Appareillage et conditions de la réactionEXAMPLE 1 Synthesis of Terpolymer Latex in "Batch" Mode 1.1 / Apparatus and Conditions of the Reaction
L'ensemble des réactions a été conduit dans un réacteur "Sovirel" simple enveloppe de 250 ml, avec un agitateur de type ancre. Compte tenu du volume du réacteur, la masse totale (réactifs + eau) engagée dans la réaction est de 150 g.All of the reactions were carried out in a 250 ml single-shell "Sovirel" reactor, with an anchor-type stirrer. Given the volume of the reactor, the total mass (reactants + water) involved in the reaction is 150 g.
La régulation de la température est assurée au moyen d'un bain d'eau thermostaté à la température de 70°C. L'agitation peut être réglée à différentes valeurs comprises entre 0 et 1000 tr/min. L'agitation la plus courante est de 250 à 300 tr/min.The temperature is regulated by means of a water bath thermostatically controlled at a temperature of 70 ° C. Stirring can be adjusted to different values between 0 and 1000 rpm. The most common agitation is 250 to 300 rpm.
Le réacteur est surmonté d'un réfrigérant, et d'une arrivée d'azote permettant le dégazage de l'ensemble du système et des solutions.The reactor is surmounted by a coolant, and a nitrogen inlet allowing the degassing of the entire system and the solutions.
Pour les synthèses en batch-shot et semi-continu, l'addition se fait au moyen de seringues et de pousse-seringues, permettant d'ajouter dans le réacteur les monomères seuls ou en emulsion à une vitesse variable, comprise entre 1 ,45 et 145 ml/h.For batch-shot and semi-continuous syntheses, the addition is done by means of syringes and syringe pumps, allowing the monomers to be added alone or in emulsion at a variable speed, between 1.45 and 145 ml / h.
La cinétique est suivie par prélèvements réguliers, et la réaction arrêtée lorsque le taux de conversion atteint les 100%, ou qu'il se stabilise (pour les réactions non complètes).The kinetics are followed by regular samples, and the reaction stopped when the conversion rate reaches 100%, or when it stabilizes (for incomplete reactions).
Le latex est mis sous bullage d'azote une demi-heure et refroidi jusqu'à température ambiante.The latex is bubbled with nitrogen for half an hour and cooled to room temperature.
1.2/ Détermination du taux de solide et du taux de coagulum Le taux de solide Ts est déterminé par la méthode des extraits secs. Une masse mι_ de latex prélevée est laissée à 120 °C jusqu'à masse constante. La masse de polymère sec rτis obtenue après évaporation complète permet le calcul du taux de solide : ms Ts = mL Le taux de coagulum représente la part de monomères introduits dans le réacteur que l'on retrouve sous forme de particules agglomérées. Ainsi :1.2 / Determination of the rate of solid and of the rate of coagulum The rate of solid Ts is determined by the method of dry extracts. A mass of latex sampled is left at 120 ° C. until constant mass. The mass of dry polymer rτis obtained after complete evaporation allows the calculation of the solid rate: m s Ts = m L The coagulum rate represents the share of monomers introduced into the reactor which is found in the form of agglomerated particles. So :
nicoagulumnicoagulum
% coagulum = m monomères% coagulum = m monomers
Le coagulum est séparé du latex par filtration sur tamis. 1.3/ Détermination du taux de conversionThe coagulum is separated from the latex by filtration through a sieve. 1.3 / Determination of the conversion rate
Le taux de conversion Te est défini par le rapport entre le taux de solide réel du latex et celui du latex théorique, corrigé du taux de solide initial, suivant formule suivante :The conversion rate Te is defined by the ratio between the real solid rate of the latex and that of the theoretical latex, corrected by the initial solid rate, according to the following formula:
Ts - TSJ Tc = Ts - TSJ Tc =
avecwith
Ts : taux de solide réel, déterminé par extrait secTs: real solid content, determined by dry extract
TSJ : taux de solide initial, dû à l'amorceur, aux tensioactifs et au tampon éventuelTSJ: initial solid level, due to the initiator, to the surfactants and to the possible buffer
Tsth : taux de solide final théorique calculé à partir des quantités introduitesTs t h: theoretical final solid rate calculated from the quantities introduced
1.4/ Détermination de la taille des particules1.4 / Determination of the particle size
La taille des particules est déterminée par diffusion quasi élastique de la lumière, sur un appareil type Coulter N4+ de la société Coultronics.The particle size is determined by quasi-elastic light scattering, on a Coulter N4 + type device from the company Coultronics.
1.5/ Synthèse du latex Les abréviations suivantes sont utilisées ci-après :1.5 / Synthesis of latex The following abbreviations are used below:
ABu acrylate de n-butyleABu n-butyl acrylate
AMA acide méthacrylateAMA methacrylate acid
KPS persulfate de potassiumKPS potassium persulfate
SDS dodécylsulfate de sodium Sty styrèneSDS sodium dodecyl sulfate Sty styrene
Les proportions des monomères pour la synthèse de terpolymères poly(styrène-co-acrylate de butyle-co-acide méthacrylique) sont fixées à 37/58/5. L'agitation est fixée à 300 tr/min. La recette type, pour un taux de solide de 50%, de cette série de latex est indiquée ci-dessous : Sty (Atochem) 29,6 gThe proportions of the monomers for the synthesis of poly (styrene-butyl co-acrylate-co-methacrylic acid) terpolymers are fixed at 37/58/5. Stirring is set at 300 rpm. The standard recipe, for a solid content of 50%, of this series of latex is indicated below: Sty (Atochem) 29.6 g
ABu (Fluka) 46,4g AMA (Aldrich) 4 g SDS (Fluka) 0,4 g (0,5% des monomères) Eau 80 gABu (Fluka) 46.4g AMA (Aldrich) 4 g SDS (Fluka) 0.4 g (0.5% of the monomers) Water 80 g
KPS (Prolabo) 0,6 g ( 0,75% des monomères) NaHCO3 (Fluka) 0,328 gKPS (Prolabo) 0.6 g (0.75% of the monomers) NaHCO 3 (Fluka) 0.328 g
Le tableau 1 ci-dessous présente les caractéristiques des latex obtenus :Table 1 below presents the characteristics of the latexes obtained:
Tableau 1Table 1
* en % massique par rapport aux monomères * in% by mass relative to the monomers
** indice de polydispersité mesuré par l'appareil IP Coulter N4 + C (Coultronics)** polydispersity index measured by the IP Coulter N4 + C device (Coultronics)
1.6/ Purification des latex1.6 / Purification of latex
Le latex légèrement dilué (20 à 30% de taux de solide) est introduit dans un tube de dialyse souple en cellulose de seuil de coupure 50 000 Da (Spectra/Pore 7), puis immergé dans l'eau distillée.The slightly diluted latex (20 to 30% solid content) is introduced into a flexible cellulose dialysis tube with a cutoff threshold of 50,000 Da (Spectra / Pore 7), then immersed in distilled water.
La dilution est nécessaire du fait de la différence de pression osmotique de part et d'autre de la membrane.Dilution is necessary due to the difference in osmotic pressure on either side of the membrane.
L'eau d'échange est renouvelée toutes les douze heures au début puis tous les jours jusqu'à obtenir une conductivité constante de cette eau.The exchange water is renewed every twelve hours at the start and then every day until a constant conductivity of this water is obtained.
L'opération globale de purification peut ainsi durer jusqu'à 15 ou 20 jours, notamment pour les latex dont la conversion n'a pas été totale.The overall purification operation can thus last up to 15 or 20 days, in particular for latexes whose conversion has not been complete.
Exemple 2 : Synthèse d'un latex en mode "batch" avec alimentation contrôlée en monomère fonctionnalisant Des latex, de même composition globale ont été synthétisés selon le procédé batch-shot "modifié", c'est-à-dire que l'ajout du reste de monomère, dont l'acide, est fait en continu et non en une seule fois après environ 90% de conversion de la majorité des monomères introduits en batch.Example 2 Synthesis of a Latex in "Batch" Mode with Controlled Supply of Functionalizing Monomers Latexes, with the same overall composition, were synthesized according to the "modified" batch-shot process, that is to say that the addition of the rest of the monomer, including the acid, is done continuously and not in one times after approximately 90% conversion of the majority of the monomers introduced in batch.
La semence est composée de styrène et d'acrylate de butyle en proportion 41/59. Elle est constituée de près de 68% de la totalité des monomères.The seed is composed of styrene and butyl acrylate in proportion 41/59. It consists of almost 68% of all the monomers.
Le tableau 2 donne la composition type des latex obtenus :Table 2 gives the typical composition of the latexes obtained:
Tableau 2 - Composition typeTable 2 - Typical composition
Le latex L 4 ci-dessous a été synthétisé en ajoutant le monomère fonctionnalisé (AMA) à une vitesse de 20 ml/h, en réalisant l'ajout 1 heure après le début de la polymérisation. Ses caractéristiques sont données dans le tableau 3 ci-dessous :The latex L 4 below was synthesized by adding the functionalized monomer (AMA) at a speed of 20 ml / h, carrying out the addition 1 hour after the start of the polymerization. Its characteristics are given in table 3 below:
Tableau 3Table 3
Le latex L 4 est soumis à une purification par dialyse comme indiqué dans l'exemple 1. Latex L 4 is subjected to a purification by dialysis as indicated in Example 1.
Exemple 3 : Etude des propriétés de résistance à l'eau en fonction du traitement de dialyse du film de latexExample 3 Study of the Water Resistance Properties as a Function of the Dialysis Treatment of the Latex Film
La pénétration de l'eau à l'intérieur du film peut contribuer à la diffusion du plomb, et, par accumulation à l'interface film/substrat, est susceptible de générer des défauts d'adhésion et des problèmes de délamination du revêtement. On a utilisé un latex styrène/acrylate de butyle/acide acryliqueThe penetration of water inside the film can contribute to the diffusion of lead, and, by accumulation at the film / substrate interface, is likely to generate adhesion defects and problems of delamination of the coating. A styrene / butyl acrylate / acrylic acid latex was used
37/59/3 dialyse ou non.37/59/3 dialysis or not.
Le film a été préparé sur plaque de Téflon® au moyen d'un tire- film conduisant à une épaisseur humide de 500 μm. Le taux de solide du latex appliqué est compris entre 30 et 50% selon la viscosité de ceux-ci. Après séchage, l'épaisseur du film est de l'ordre de 200 μm.The film was prepared on a Teflon® plate using a film puller leading to a wet thickness of 500 μm. The solid content of the latex applied is between 30 and 50% depending on the viscosity of the latter. After drying, the film thickness is around 200 μm.
Le séchage s'effectue en deux temps, le latex déposé sur Téflon® étant d'abord laissé à 20 °C pendant 20 minutes, puis placé à 50 °C pendant une heure.The drying takes place in two stages, the latex deposited on Teflon® being first left at 20 ° C for 20 minutes, then placed at 50 ° C for one hour.
Le film est ensuite laissé à 20 °C pendant trois heures afin de simuler la mise en œuvre sur canalisation en milieu réel dans l'intervalle d'une journée de 10 heures. Il est ensuite découpé en carrés de 9 cm2, en six exemplaires.The film is then left at 20 ° C. for three hours in order to simulate the implementation on pipe in real medium in the interval of a day of 10 hours. It is then cut into 9 cm 2 squares, in six copies.
La sensibilité à l'eau des films est évaluée par gravimétrie suite à une immersion continue dans l'eau à 20 °C, sur les films libres de tout support. La surface exposée est donc le double de la surface réelle de films déposés sur un substrat.The water sensitivity of the films is evaluated by gravimetry following continuous immersion in water at 20 ° C, on the films free of any support. The exposed surface is therefore twice the real surface of films deposited on a substrate.
Pour visualiser la quantité d'eau absorbée M(t) relativement à la masse de polymère M0 en contact avec l'eau, on a tracé le graphe :To visualize the quantity of water absorbed M (t) relative to the mass of polymer M 0 in contact with water, we have drawn the graph:
M(t)/M0 = f(t), avec M(t)= masse d'eau absorbée à l'instant t, en g Mo = masse du polymère en contact avec l'eau, en g t = temps, en hM (t) / M 0 = f (t), with M (t) = mass of water absorbed at time t, in g Mo = mass of the polymer in contact with water, in gt = time, in h
Le graphe M(t)/Mo (exprimé en pourcentage)^ f(t) (exprimé en h) est représenté sur la figure 1. Les symboles suivants sont utilisés : -*- représente le latex dialyse -m- représente le latex non dialyseThe graph M (t) / Mo (expressed as a percentage) ^ f (t) (expressed in h) is represented in FIG. 1. The following symbols are used: - * - represents the latex dialysis -m- represents the latex not dialysis
Ce graphe montre que, pour un même latex, l'absorption d'eau est très faible et reste constante lorsque le latex a été dialyse.This graph shows that, for the same latex, the water absorption is very low and remains constant when the latex has been dialyzed.
Exemple 4 : Test de diffusion du plomb dans une canalisation revêtue d'un film de latexExample 4 Test of diffusion of lead in a pipe coated with a latex film
On a utilisé des sections de canalisation de 5 cm de long et de 2 cm de diamètre, issues de réseaux démantelés.Pipe sections 5 cm long and 2 cm in diameter were used, coming from dismantled networks.
Dans un premier temps, la canalisation est remplie entièrement d'une solution d'acide phosphorique 3N. Après un temps de contact de 10 à 15 minutes, la canalisation est vidangée, rincée et séchée à température ambiante.First, the pipeline is completely filled with a 3N phosphoric acid solution. After a contact time of 10 to 15 minutes, the pipe is drained, rinsed and dried at room temperature.
L'enduction par le latex se fait de la même manière, sans avoir besoin de laisser stagner le latex. Le tuyau est rempli, puis vidangé sans attendre. Aucun excédent de latex ne doit rester dans le tuyau. Les extrémités du tube sont également enduites de latex afin d'éviter tout contact intempestif du plomb avec l'eau.The latex coating is done in the same way, without the need to allow the latex to stagnate. The hose is filled, then drained without waiting. No excess latex should remain in the hose. The ends of the tube are also coated with latex to avoid inadvertent contact of lead with water.
Cette première couche est mise à sécher pendant une heure à 50 °C, en position verticale dans une enceinte thermostatée. A l'issue de ce premier cycle de séchage, la deuxième enduction est pratiquée de la même façon, après un temps de refroidissement d'environ 5 à 10 minutes.This first layer is allowed to dry for one hour at 50 ° C, in a vertical position in a thermostatically controlled enclosure. At the end of this first drying cycle, the second coating is carried out in the same way, after a cooling time of approximately 5 to 10 minutes.
Les extrémités sont protégées et isolées en les trempant dans la paraffine chaude sur une hauteur de 5 mm environ.The ends are protected and insulated by dipping them in hot paraffin over a height of about 5 mm.
Après l'étape complète d'enduction (dépendante du nombre de couches) la section de conduite est laissée à 20 °C pendant 3 heures. Elle est d'abord obturée au moyen de parafilm® pour éviter l'évaporation, et placée dans une enceinte thermostatée à 30 °C. Pour toutes les opérations de remplissage, l'une des extrémités du tube est obturée à l'aide de plusieurs couches de parafilm®.After the complete coating step (depending on the number of layers) the pipe section is left at 20 ° C for 3 hours. It is first closed with parafilm® to prevent evaporation, and placed in an enclosure thermostatically controlled at 30 ° C. For all filling operations, one end of the tube is closed with several layers of parafilm®.
Un essai préliminaire consiste en une stagnation de 2 jours de l'eau introduite dans ces sections de canalisation. Suivant la concentration en plomb mesurée, la canalisation est rincée, et remplie à nouveau d'eau distillée. Cette seconde stagnation dure 15 jours.A preliminary test consists of a 2-day stagnation of the water introduced into these sections of pipeline. Depending on the lead concentration measured, the pipe is rinsed and filled again with distilled water. This second stagnation lasts 15 days.
La concentration en plomb est mesurée, après agitation du montage à la fin de la durée de stagnation, à l'aide d'un analyseur SCANNING SA - 1000 (Palintest Instruments) sur des échantillons de 5 ml.The lead concentration is measured, after stirring the assembly at the end of the stagnation period, using a SCANNING SA-1000 analyzer (Palintest Instruments) on 5 ml samples.
Les résultats obtenus au bout de 2 jours et au bout de 15 jours sont rapportés dans le tableau 4 ci-dessous :The results obtained after 2 days and after 15 days are reported in Table 4 below:
Tableau 4Table 4
3 couches 3 layers

Claims

REVENDICATIONS
1. Procédé de revêtement de la paroi interne d'une canalisation par un film protecteur, comprenant la formation dudit film protecteur à partir d'au moins un latex, caractérisé en ce que ledit latex, dilué à 20% d'extrait sec dans de l'eau déminéralisée, présente une conductivité inférieure à 1,3 mS/cm.1. A method of coating the internal wall of a pipe with a protective film, comprising the formation of said protective film from at least one latex, characterized in that said latex, diluted to 20% of dry extract in demineralized water has a conductivity of less than 1.3 mS / cm.
2. Procédé selon la revendication 1 , caractérisé en ce que ledit latex, dilué à 20% d'extrait sec dans de l'eau déminéralisée, présente une conductivité inférieure à 1 mS/cm. 2. Method according to claim 1, characterized in that said latex, diluted to 20% of dry extract in demineralized water, has a conductivity less than 1 mS / cm.
3. Procédé selon les revendications 1 ou 2, caractérisé en ce que ledit latex ,dilué à 20% d'extrait sec dans de l'eau déminéralisée, présente une conductivité inférieure à 0,9 mS/cm.3. Method according to claims 1 or 2, characterized in that said latex, diluted to 20% of dry extract in demineralized water, has a conductivity less than 0.9 mS / cm.
4. Procédé selon les revendications 1 ou 2, caractérisé en ce que ladite canalisation est destinée à l'alimentation en eau, cette dernière ayant une température inférieure à environ 30°C, de préférence inférieure ou égale à environ 20°C.4. Method according to claims 1 or 2, characterized in that said pipe is intended for the supply of water, the latter having a temperature below about 30 ° C, preferably less than or equal to about 20 ° C.
5. Procédé selon la revendication 3, caractérisé en ce que ladite canalisation est destinée à l'alimentation en eau potable.5. Method according to claim 3, characterized in that said pipe is intended for the supply of drinking water.
6. Procédé selon l'une quelconque des revendications 1 à 4, caractérisé en ce que ladite canalisation est en matériau métallique.6. Method according to any one of claims 1 to 4, characterized in that said pipe is made of metallic material.
7. Procédé selon la revendication 5, caractérisé en ce que ladite canalisation est en plomb.7. Method according to claim 5, characterized in that said pipe is made of lead.
8. Procédé selon l'une quelconque des revendications 1 à 7, caractérisé en ce que le latex est formé par polymérisation ou copolymérisation de monomères éthyléniquement insaturés choisis parmi le styrène et ses dérivés, le butadiène, le chloroprène, les esters (méth)acryliques, les esters vinyliques et les nitriles vinyliques.8. Method according to any one of claims 1 to 7, characterized in that the latex is formed by polymerization or copolymerization of ethylenically unsaturated monomers chosen from styrene and its derivatives, butadiene, chloroprene, (meth) acrylic esters , vinyl esters and vinyl nitriles.
9. Procédé selon l'une quelconque des revendications 1 à 8, caractérisé en ce qui concerne ledit monomère est choisi parmi les esters de l'acide acrylique ou de l'acide méthacrylique avec des alcools en C1-C12 hydrogénés ou fluorés. 9. Method according to any one of claims 1 to 8, characterized with regard to said monomer is chosen from esters of acrylic acid or methacrylic acid with C 1 -C 12 alcohols hydrogenated or fluorinated.
10. Procédé selon la revendication 9, caractérisé en ce que ledit monomère est choisi parmi l'acrylate de méthyle, l'acrylate d'éthyle, l'acrylate de propyle, l'acrylate de n-butyle, l'acrylate d'isobutyle, l'acrylate de 2-éthyIhexyle, l'acrylate de t-butyle, le méthacrylate de méthyle, le méthacrylate d'éthyle, le méthacrylate de n-butyle et le méthacrylate d'isobutyle.10. Method according to claim 9, characterized in that said monomer is chosen from methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate , 2-ethylhexyl acrylate, t-butyl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate and isobutyl methacrylate.
11. Procédé selon l'une quelconque des revendications 1 à 8, caractérisé en ce que ledit monomère est un nitrile vinylique en C3-C12.11. Method according to any one of claims 1 to 8, characterized in that said monomer is a C 3 -C 12 vinyl nitrile.
12. Procédé selon l'une quelconque des revendications 1 à 7, caractérisé en ce que le latex est formé par polymérisation ou copolymérisation de monomères éthyléniquement insaturés choisis parmi : les esters vinyliques d'acides carboxyliques, les halogénures de vinyle, les acides mono- et di- carboxyliques insaturés éthyléniques et les mono- alkylesters des acides dicarboxyliques avec les alcanols en C1-C4 et leurs dérivés N-substitués, les amides d'acides carboxyliques insaturés, les monomères éthyléniques comportant un groupe acide sulfonique et ses sels alcalins ou d'ammonium, les amides de la vinylamine, - les monomères éthyléniques insaturés comportant un groupe amino secondaire, tertiaire ou quaternaire, ou un groupe hétérocyclique contenant de l'azote, les monomères zwitterioniques, les monomères permettant une réticulation lors de la mise en oeuvre, par exemple par voie chimique, thermique ou photochimique, lesdits monomères éthyléniquement insaturés étant utilisés seuls ou copolymérisés avec des monomères choisis parmi le styrène et ses dérivés, le butadiène, le chloroprène, les esters (méth)acryliques, les esters vinyliques et les nitriles vinyliques. 12. Method according to any one of claims 1 to 7, characterized in that the latex is formed by polymerization or copolymerization of ethylenically unsaturated monomers chosen from: vinyl esters of carboxylic acids, vinyl halides, mono acids and ethylenic unsaturated dicarboxylic acids and monoalkyl esters of dicarboxylic acids with C 1 -C 4 alkanols and their N-substituted derivatives, unsaturated carboxylic acid amides, ethylenic monomers containing a sulfonic acid group and its alkaline salts or of ammonium, the amides of vinylamine, - the unsaturated ethylenic monomers comprising a secondary, tertiary or quaternary amino group, or a heterocyclic group containing nitrogen, the zwitterionic monomers, the monomers allowing a crosslinking during the setting works, for example by chemical, thermal or photochemical means, said ethylenically monomers unsaturated being used alone or copolymerized with monomers chosen from styrene and its derivatives, butadiene, chloroprene, (meth) acrylic esters, vinyl esters and vinyl nitriles.
13. Procédé selon l'une quelconque des revendications 1 à 7, caractérisé en ce que le latex est formé par polymérisation ou copolymérisation de monomères de qualité alimentaire. 13. Method according to any one of claims 1 to 7, characterized in that the latex is formed by polymerization or copolymerization of food grade monomers.
14. Procédé selon l'une quelconque des revendications 1 à 8, caractérisé en ce que les monomères utilisés pour former le latex sont choisis parmi l'acide acrylique et ses dérivés, l'acide méthacrylique et ses dérivés, et le styrène et ses dérivés. 14. Method according to any one of claims 1 to 8, characterized in that the monomers used to form the latex are chosen from acrylic acid and its derivatives, methacrylic acid and its derivatives, and styrene and its derivatives .
15. Procédé selon l'une quelconque des revendications 1 à 14, caractérisé en ce que ledit latex comprend un polymère ou un copolymère ayant une température de formation de film comprise entre 0°C et 20°C.15. Method according to any one of claims 1 to 14, characterized in that said latex comprises a polymer or a copolymer having a film forming temperature between 0 ° C and 20 ° C.
16. Procédé selon l'une quelconque des revendications 1 à 15, caractérisé en ce que ledit latex comprend un polymère ou un copolymère ayant une température de transition vitreuse (Tg) inférieure à 20°C.16. Method according to any one of claims 1 to 15, characterized in that said latex comprises a polymer or a copolymer having a glass transition temperature (T g ) below 20 ° C.
17. Procédé selon l'une quelconque des revendications 1 à 16, caractérisé en ce que ledit latex comprend un polymère ou un copolymère ayant une température de transition vitreuse (Tg) comprise entre 0 et 10°C.17. Method according to any one of claims 1 to 16, characterized in that said latex comprises a polymer or a copolymer having a glass transition temperature (T g ) between 0 and 10 ° C.
18. Procédé selon l'une quelconque des revendications 1 à 17, caractérisé en ce que le diamètre des particules de latex est compris entre18. Method according to any one of claims 1 to 17, characterized in that the diameter of the latex particles is between
10 nm et 5 μm, de préférence entre 100 et 300 nm.10 nm and 5 μm, preferably between 100 and 300 nm.
19. Procédé selon les revendications 1 à 18, caractérisé en ce que ledit latex a un taux de solides supérieur ou égal à 20%, de préférence de 30 à 50%. 19. Method according to claims 1 to 18, characterized in that said latex has a solids content greater than or equal to 20%, preferably from 30 to 50%.
20. Procédé selon les revendications 1 à 18, caractérisé en ce que ledit latex a un taux de coagulum inférieur à 10%, de préférence inférieur à 0,1 %.20. Method according to claims 1 to 18, characterized in that said latex has a coagulum rate of less than 10%, preferably less than 0.1%.
21. Procédé selon l'une quelconque des revendications 1 à 19, caractérisé en ce que le latex, préalablement à son utilisation pour former un film, est soumis à un traitement de purification destiné à diminuer la concentration en constituants hydrosolubles dudit latex.21. Method according to any one of claims 1 to 19, characterized in that the latex, prior to its use to form a film, is subjected to a purification treatment intended to reduce the concentration of water-soluble constituents of said latex.
22. Procédé selon la revendication 21 , caractérisé en ce que le traitement de purification est effectué par dialyse et/ou ultrafiltration.22. Method according to claim 21, characterized in that the purification treatment is carried out by dialysis and / or ultrafiltration.
23. Procédé selon l'une quelconque des revendications 21 ou 22, caractérisé en ce que ledit latex à l'issue de ce traitement présente une concentration en constituants hydrosolubles inférieure à celle du latex obtenu à l'issue de la polymérisation ou de la copolymérisation. 23. Method according to any one of claims 21 or 22, characterized in that said latex at the end of this treatment has a lower concentration of water-soluble constituents than that of the latex obtained at the end of the polymerization or of the copolymerization .
24. Procédé selon l'une quelconque des revendications 1 à 23, caractérisé en ce qu'il comprend les étapes suivantes : on remplît une canalisation à l'aide d'un latex, on vidange ladite canalisation de manière à laisser s'écouler le trop-plein de latex et à former une couche de latex sur la paroi interne de la canalisation, on chauffe la couche de latex de manière à former le film protecteur sur la paroi interne de ladite canalisation.24. Method according to any one of claims 1 to 23, characterized in that it comprises the following steps: filling a pipe with a latex, draining said pipe so as to let the latex overflow and to form a layer of latex on the internal wall of the pipe, the latex layer is heated so as to form the protective film on the internal wall of said pipe.
25. Procédé selon la revendication 24, caractérisé en ce que le remplissage de la canalisation est effectué à température ambiante. 25. The method of claim 24, characterized in that the filling of the pipe is carried out at room temperature.
26. Procédé selon les revendications 24 ou 25, caractérisé en ce qu'on chauffe la couche de latex à une température de l'ordre de 30 à 80°C.26. The method of claims 24 or 25, characterized in that the latex layer is heated to a temperature of the order of 30 to 80 ° C.
27. Procédé selon l'une quelconque des revendications 1 à 26, caractérisé en ce que la paroi interne de ladite canalisation est revêtue de plusieurs films de latex superposés. 27. Method according to any one of claims 1 to 26, characterized in that the internal wall of said pipe is coated with several superimposed latex films.
28. Procédé selon la revendication 27, caractérisé en ce que chacun des films de latex est appliqué après séchage du film précédent.28. The method of claim 27, characterized in that each of the latex films is applied after drying the previous film.
29. Procédé selon les revendications 27 ou 28, caractérisé en ce que chacun des films a une épaisseur comprise entre environ 50 à 500 μm, de préférence 100 à 250 μm. 29. Method according to claims 27 or 28, characterized in that each of the films has a thickness of between approximately 50 to 500 μm, preferably 100 to 250 μm.
30. Procédé selon l'une quelconque des revendications 27 à 29, caractérisé en ce que la paroi interne de ladite canalisation est revêtue de deux films de latex superposés.30. Method according to any one of claims 27 to 29, characterized in that the internal wall of said pipe is coated with two superimposed latex films.
31. Procédé selon l'une quelconque des revendications 25 à 30, caractérisé en ce que le remplissage de la canalisation est effectué sous pression. 31. Method according to any one of claims 25 to 30, characterized in that the filling of the pipe is carried out under pressure.
32. Procédé selon la revendication 31, caractérisé en ce que ladite pression est de l'ordre de 2 à 50 Pa.32. Method according to claim 31, characterized in that said pressure is of the order of 2 to 50 Pa.
33. Procédé selon l'une des revendications 6 à 32, caractérisé en ce que ladite canalisation est, préalablement au revêtement de sa paroi interne, soumise à un traitement au moyen d'un acide. 33. Method according to one of claims 6 to 32, characterized in that said pipe is, prior to coating of its internal wall, subjected to a treatment using an acid.
34. Procédé selon la revendication 33, caractérisé en ce que ledit traitement est effectué au moyen d'acide orthophosphorique. 34. Method according to claim 33, characterized in that said treatment is carried out by means of orthophosphoric acid.
35. Utilisation d'au moins un latex pour former un film destiné au revêtement de la paroi interne d'une canalisation, pour réduire ou supprimer le relargage d'un ou plusieurs constituants du matériau de ladite canalisation dans un liquide conduit par cette canalisation. 35. Use of at least one latex to form a film intended for coating the internal wall of a pipe, to reduce or eliminate the release of one or more constituents of the material of said pipe into a liquid carried by this pipe.
36. Tuyau ou portion de tuyau, caractérisé en ce que sa paroi interne est revêtue d'un film obtenu à partir d'au moins un latex, ledit latex présentant une conductivité inférieure à 1,3 mS/cm, lorsqu'il est dilué à 20% d'extrait sec dans de l'eau déminéralisée.36. Pipe or portion of pipe, characterized in that its internal wall is coated with a film obtained from at least one latex, said latex having a conductivity of less than 1.3 mS / cm, when diluted 20% dry extract in demineralized water.
37. Tuyau ou portion de tuyau selon la revendication 36, caractérisé en ce que ledit revêtement est susceptible d'être effectué par le procédé selon l'une quelconque des revendications 1 à 34. 37. Pipe or portion of pipe according to claim 36, characterized in that said coating is capable of being carried out by the method according to any one of claims 1 to 34.
EP04742560A 2003-04-22 2004-04-22 Method of coating the inner wall of a pipe with a latex film Withdrawn EP1620673A2 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR0304925A FR2854223B1 (en) 2003-04-22 2003-04-22 PROCESS FOR COATING THE INTERNAL WALL OF A LATEX FILM PIPING
PCT/FR2004/000985 WO2004094890A2 (en) 2003-04-22 2004-04-22 Method of coating the inner wall of a pipe with a latex film

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EP (1) EP1620673A2 (en)
AU (1) AU2004233421A1 (en)
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WO (1) WO2004094890A2 (en)

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WO2010120617A2 (en) * 2009-04-16 2010-10-21 3M Innovative Properties Company Method and composition suitable for coating drinking water pipelines
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CN103173071A (en) * 2013-03-07 2013-06-26 王程皓 Mercerizing emulsion paint for interior walls and preparation method thereof
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CN105255266A (en) * 2014-07-14 2016-01-20 开平市开物化工建材有限公司 Internal wall mercerizing latex paint based on HUER thickening agents, and production process thereof
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FR2854223B1 (en) 2006-07-14
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US20070160754A1 (en) 2007-07-12
AU2004233421A1 (en) 2004-11-04
FR2854223A1 (en) 2004-10-29
WO2004094890A2 (en) 2004-11-04

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