Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L27/00—Compositions of 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 halogen; Compositions of derivatives of such polymers
  • C08L27/02—Compositions of 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 halogen; Compositions of derivatives of such polymers not modified by chemical after-treatment
  • C08L27/12—Compositions of 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 halogen; Compositions of derivatives of such polymers not modified by chemical after-treatment containing fluorine atoms
  • C08L27/16—Homopolymers or copolymers or vinylidene fluoride
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J3/00—Processes of treating or compounding macromolecular substances
  • C08J3/005—Processes for mixing polymers
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L27/00—Compositions of 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 halogen; Compositions of derivatives of such polymers
  • C08L27/02—Compositions of 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 halogen; Compositions of derivatives of such polymers not modified by chemical after-treatment
  • C08L27/12—Compositions of 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 halogen; Compositions of derivatives of such polymers not modified by chemical after-treatment containing fluorine atoms
  • C08L27/20—Homopolymers or copolymers of hexafluoropropene
• • 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
  • F16L11/00—Hoses, i.e. flexible pipes
  • F16L11/04—Hoses, i.e. flexible pipes made of rubber or flexible plastics
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L2203/00—Applications
  • C08L2203/18—Applications used for pipes
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L2205/00—Polymer mixtures characterised by other features
  • C08L2205/02—Polymer mixtures characterised by other features containing two or more polymers of the same C08L -group
  • C08L2205/025—Polymer mixtures characterised by other features containing two or more polymers of the same C08L -group containing two or more polymers of the same hierarchy C08L, and differing only in parameters such as density, comonomer content, molecular weight, structure
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L2205/00—Polymer mixtures characterised by other features
  • C08L2205/03—Polymer mixtures characterised by other features containing three or more polymers in a blend
  • C08L2205/035—Polymer mixtures characterised by other features containing three or more polymers in a blend containing four or more polymers in a blend
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L2207/00—Properties characterising the ingredient of the composition
  • C08L2207/04—Thermoplastic elastomer

Definitions

• the present invention relates to a fluorinated polymeric composition, processes for the manufacture thereof, and products that can be made therefrom, including polymeric sheaths of flexible hoses used for transporting fluids from petroleum marine, or "off-shore", and land, or “on-shore”) or gas.
• the transport of chemicals in the liquid or gaseous state in pipes has many advantages: it is more economical once the infrastructure is in place; it allows the transport of large volumes; it ensures a great security of supply, thanks to a regular flow; finally, it is safer than rail or road.
• PVDF polyvinylidene fluoride
• Flexible hoses are also used for the transport of oil or natural gas extracted from submarine or terrestrial deposits. These pipes are formed of multilayer structures including polymeric sheaths and reinforcing layers of metal or composite materials.
• Flexible hoses include, from the inside to the outside:
• At least one internal sealing tube in contact with the transported fluid consisting of a polymeric material
• BE 832851 discloses fluorinated elastomers comprising a molar proportion of 50 to 85% of VDF and 15 to 25% of hexafluoropropylene (HFP), ie a mass proportion of 47 to 71% of VDF and 29 to 53% of HFP, which are used for the manufacture of PVDF molded bodies comprising from 1 to 30% by weight of fluoroelastomer.
• HFP hexafluoropropylene
• EP 1342752 discloses PVDF-based compositions comprising: (A) a PVDF homopolymer or a VDF-based copolymer; (B) a fluoroelastomer; (C) optionally a plasticizer.
• the fluorinated elastomer (B) is present in an amount of from 0.5 to 10 parts by weight per 100 parts of homopolymer or copolymer (A) and from 0 to 10 parts by weight of a plasticizer (C) with the condition further that the sum of (B) plus (C) is from 0.5 to 10.5 parts by weight.
• compositions correspond to the following mass proportions: 89.5 to 90.5% of a PVDF homopolymer or a VDF-based copolymer (A); 0.5 to 9% of a fluoroelastomer (B); 0 to 9% of a plasticizer (C).
• A a PVDF homopolymer or a VDF-based copolymer
• B a fluoroelastomer
• C a plasticizer
• EP 608639 discloses polymeric compositions comprising, by weight, 60 to 80% of PVDF, 20 to 40% of a thermoplastic copolymer of VDF and another fluorinated comonomer (present in amounts of 5 to 25% in the copolymer), and from 5 to 20% of a plasticizer (relative to the sum of the PVDF and the copolymer).
• thermoplastic copolymers envisaged include VDF / HFP copolymers.
• the HFP contents indicated in the copolymers which are disclosed in the examples are of the order However, these compositions undergo an extraction of the plasticizer in contact with certain chemical substances. As a result, the sheaths made with these compositions do not maintain a stable geometry, their volume and therefore their thickness tending to decrease over time.
• An excessive decrease in the thickness of the sheath may therefore have the effect of degrading the crimping pressure and the sealing of the nozzle.
• WO 2006/045753 discloses polymeric compositions comprising a PVDF homopolymer, a thermoplastic fluorinated copolymer and a third component which can be a plasticizer at up to 5% by weight, a perfluorinated polymer or a low molecular weight VDF polymer.
• the thermoplastic fluorinated copolymer may for example be a copolymer of VDF and another fluorinated comonomer, which may be present in a content of 5 to 25%.
• the mixture of PVDF homopolymer and fluorinated copolymer has an average intrinsic viscosity of less than 2 dl / g.
• the polymeric composition has a melt apparent viscosity of less than or equal to 60,000 Pa.s at a rate gradient of 1 s- 1 .
• the fluorinated polymeric compounds of the tubular structures made with such compositions In particular, when the structures are subjected to repeated movements due to marine currents, the fatigue strength of these fluorinated polymeric compounds is considered insufficient.
• FR 2987624 discloses compositions comprising a PVDF homopolymer, an elastomeric fluorinated copolymer and a plasticizer.
• the copolymer has elastomeric properties which it confers on the fluorinated polymer compound and which makes it possible not only to increase the fatigue strength of said compound, but also to improve the cold strength. This is an essential difference with the object of the document WO 2006/045753, where, precisely, it is sought for compositions capable of forming non-elastomeric fluorinated polymeric compounds.
• the extraction of the plasticizer that occurs during the lifetime of the tubular structure in addition to modifying the geometry of the sheaths (volume variation and thickness) as already mentioned above, gradually leads to a loss of properties initially provided. by plasticizing (flexibility, resilience), thus limiting the life of articles based on these compositions.
• the object of the present invention is therefore to develop a novel polymeric composition based on a particular PVDF homopolymer, an elastomeric fluorinated copolymer and a third low viscosity fluorinated component, said composition having mechanical properties and improved chemical compared to known compositions, and which do not evolve over the life of the pipe in service to manufacture pipes and pipes remaining mechanically reliable in the long term especially for the monogaine pressure application used in the field off-shore.
• thermoplastic polymeric composition comprising the following components A, B and C:
• PVDF vinylidene polyfluoride homopolymer
• FCTHM very high molecular weight chains
• VDF vinylidene fluoride
• the polymeric composition according to the invention is free of plasticizer.
• component A is a PVDF homopolymer comprising a fraction of very high molecular weight chains (FCTHM), which are defined as chains with a molar mass greater than 3,000,000 g / mol, including non-transferred chains. or late transferred (FCNT) defined below.
• FCTHM very high molecular weight chains
• the other chains of component A are made by initiation and transfer or earlier transfer and have molar masses below 3,000,000 g / mol.
• the mass proportion of chains of very high molar mass in component A is calculated by the following formula:
• the mass proportion of chains with a molecular weight of less than 3000000 g / mol expressed as polymethyl methacrylate equivalent in component A is determined by steric exclusion chromatography under the conditions described below.
• the dimethylsulfoxide (DMSO) to which sodium nitrate (NaN0 3 ) at a concentration of 0.1 mol / L has been added is both the eluent and the solvent of the samples.
• the concentration of the samples of component A prepared is of 2 g / L, the dissolution is made for 4 hours at a temperature of 95 ° C.
• the solution obtained is filtered using a syringe filter with a porosity of 0.45 ⁇ m and a volume of 200 ⁇ m is injected into the size exclusion chromatography line.
• This is typically provided with 2 columns in series of length 300 mm and diameter 8 mm, particle size 7 ⁇ , porosity 100 Angstrom and 1000 Angstrom, regulated temperature at 50 ° C.
• Polymer Standards Service columns referenced PSS PFG 1000 Angstrom and PSS PFG 100 Angstrom were used.
• the detection at the column outlet is done by a differential refractometer. It is also regulated in temperature at 50 ° C.
• the standards used for calibration of the columns are narrow polymethyl methacrylates (PMMA) covering the column separation range.
• the proportion of chains of very high molecular weight thus calculated represents up to 50% by weight of component A, including the terminal.
• Component A has a melt flow index of less than or equal to 15 g / 10 min, advantageously less than or equal to 10 g / 10 min, preferably less than or equal to 5 g / 10 min, according to the standard ISO 1,133.
• Component B is present in the composition at a mass content higher than
• the comonomer is hexafluoropropylene
• the elastomeric copolymer is present in the composition in a mass proportion of more than 10 to 40%, advantageously 15 to 40%, preferably 17 to 35%, inclusive.
• the proportion by weight of comonomer in the copolymer is greater than 25%.
• it is: greater than or equal to 26%, and / or less than or equal to 40%, preferably less than or equal to 37%.
• Component C is a VDF homopolymer having a lower viscosity than component A; it is present in the composition in a mass proportion ranging from 1 to 20%, in particular from 2 to 18% and preferably from 5 to 15%.
• the ratio of the apparent melt viscosities of components A and C is greater than or equal to 5, in particular greater than or equal to 10 and preferably greater than or equal to 50. This ratio is less than 500, preferably less than 400
• the apparent melt viscosities of components A and C are expressed in Pa.s and measured on a capillary rheometer at a temperature of 230 ° C. and a shear of 100s -1 .
• thermoplastic polymer composition consists of:
• FCTHM very high molar mass
• the subject of the invention is also a process for the manufacture of the above composition, comprising the mixture of homopolymer, copolymer, fluorinated modifier and any additives.
• This manufacturing method comprises any method which makes it possible to obtain a homogeneous mixture of the various constituents. Among these methods, mention may be made of the mixture in the molten or dry state.
• the composition according to the invention is prepared by melt blending all the constituents, on a compounding tool such as a twin-screw extruder, a co-kneader or an internal or cylinder mixer.
• a compounding tool such as a twin-screw extruder, a co-kneader or an internal or cylinder mixer.
• the homopolymer of PVDF (component A) and the elastomeric copolymer (component B) are in dry form during mixing, preferably in the form of powders, and preferably the mixture with component C is carried out at room temperature.
• the molten state on a compounding tool such as a twin-screw extruder, a co-kneader or an internal or cylinder mixer.
• the above process comprises mixing the PVDF homopolymer (component A) and the elastomeric copolymer (component B) in latex form, drying the homopolymer and copolymer mixture, and the Combination of the dried mixture with the component C is carried out in the molten state on a compounding tool such as a twin-screw extruder, a comalizer or an internal or cylinder mixer.
• a compounding tool such as a twin-screw extruder, a comalizer or an internal or cylinder mixer.
• composition according to the invention obtained by the manufacturing method described above can then be transformed for use in the form of pipes or cables, in particular using tools such as an extruder equipped with a suitable die. .
• the subject of the invention is also, in general, a tube comprising at least one layer consisting of the composition according to the invention.
• said tube is intended to be used as a polymeric sheath of flexible hoses used for transporting fluids from oil and gas operations.
• the sheath can be used, in combination with at least one reinforcing layer and possibly an outer protective sheath, as a flexible hose for transporting fluids from oil or gas operations.
• said tube is a land transport pipe of products in the gaseous state.
• the aforementioned pipe is for the transport of gaseous products, especially for the transport of hydrogen, oxygen, water vapor, carbon monoxide, ammonia, hydrogen fluoride, hydrochloric acid, hydrogen sulphide, any gas from the cracking of hydrocarbons, or mixtures thereof.
• said tube is intended for the ground transportation of products in the liquid state, for example the transport of water, solvents, petroleum products, or mixtures thereof.
• the aforementioned pipe is a service station underground pipe or a vehicle fuel supply pipe.
• the invention also relates to an electric cable made from the above-mentioned composition.
• the invention also relates to the use of the composition described above, for the manufacture of pipes or electrical cables.
• the present invention overcomes the disadvantages of the state of the art.
• composition according to the invention makes it possible to manufacture pipes and pipes that remain mechanically reliable in the long term.
• the composition according to the invention is particularly suitable for the manufacture of polymeric sheaths for flexible hoses for the transport of fluids from petroleum operations and pipes for the transport of liquid or gaseous synthesis products (for example for the transport of hydrogen).
• the composition according to the invention is particularly suitable for being implemented by extrusion or coextrusion, which allows its transformation into tubes.
• a PVDF homopolymer of low viscosity makes it possible to lower the viscosity of the composition in order to make it easily transformable by extrusion or coextrusion in the molten state.
• the use for this purpose of a PVDF homopolymer of lower viscosity than that of component A (component C) makes it possible to obtain a 100% fluorinated composition, in which all the components are compatible and which do not encounter any problems.
• selective degradation and / or extraction of the plasticizer in contact with certain chemical substances known during the use of a plasticizer such as dibutyl sebacate (DBS).
• PVDF homopolymer of low viscosity in place of an extractable plasticizer makes it possible to preserve the mechanical properties of the composition over time, in particular the resistance to impact and fatigue and to avoid the volume variation of the objects obtained from the composition.
• the composition is used for the manufacture of polymer sheaths for flexible hoses intended for the transport of fluids from petroleum operations and pipes for the transport of liquid or gaseous synthesis products (for example for the transport of hydrogen)
• the hose considered is mechanically reliable in the long term and its volume is conserved over time which allows a simplified design of the tips.
• thermoplastic polymer composition comprising the following 3 components:
• FCTHM very high molar mass
• Component A is a PVDF homopolymer comprising up to 50% by weight of chains of molar mass greater than 3,000,000 g / mol, representing the fraction of chains of very high molar mass. Said fraction is advantageously between 20 to 50%, preferably 25 to 45% by weight of component A.
• These polymers are prepared by a synthesis process, especially in emulsion, in which:
• VDF vinylene fluoride
• a dispersion of VDF (vinylidene fluoride) in water is produced, optionally with the aid of a surfactant, the said dispersion being initially brought into contact with a non-organic initiator soaked in water capable of causing the polymerization of the monomers; and then, a portion of the PVDF having been formed in the presence of the non-organic initiator dissolved in water, is added: either (i) a chain transfer agent capable of propagating the polymerization, said polymerization is then initiated by a non-organic initiator soluble in water or by an organic initiator, or (ii) an organic initiator capable of to also carry out chain transfer and optionally a non-organic initiator soluble in water.
• VDF vinylene fluoride
• the principle of this process is based on the formation, at the beginning of polymerization, of a fraction of very high molecular weight macro-molecular chains, produced before the introduction of transfer agent (or before a transfer-type secondary reaction or termination helping to strongly limit the chain length) and without initiator capable of inducing a transfer reaction.
• the reaction therefore starts without a transfer agent (CTA), and the first charge of CTA is injected at a conversion rate of the monomers, for example of the order of 5% by weight.
• the necessary dose of CTA can then be introduced incrementally or continuously, the total amount and the rate of introduction to adjust the average molar mass of the polymer.
• the product obtained will show a specific molecular weight distribution with a first population of very high mass and a second population of limited mass.
• the polymerization step after addition of the first dose of transfer agent can also be carried out under the effect of an organic initiator whose contribution to the transfer reactions will be more or less important.
• FCTHM is still obtained during the first polymerization step in the presence of the non-organic initiator, and a second fraction of moderate molar mass is formed under the sole action of the organic initiator.
• the rate of conversion of the VDF before the first injection of CTA determines the fraction of very high-mass chains (in particular chains not transferred or transferred late) formed without transfer agent called "non-transferred chain fraction". Then the very high mass chains having been formed the number of injections or the rate of introduction of the CTA determines the distribution of the molar masses of the PVDF fraction which is not very high mass.
• the total volume of CTA is not a critical parameter. It must be adjusted to set the average molar mass of the polymer that is associated with the melt viscosity. The volume of water in which the dispersion of the monomers is carried out, the amounts of surfactant, initiator and CTA are readily determinable by those skilled in the art.
• the polymerization is carried out in a stirred reactor, then the PVDF is separated everywhere (it is in the form of solid particles) and the water is separated.
• these techniques are known per se and are described in US Patents 4025709, US 4569978, US 4360652, EP 626396 and EP 0655468.
• the aqueous emulsion is polymerized at a temperature of 50 to 130 ° C.
• the polymerization is carried out at an absolute pressure of 40 to 120 bar.
• surfactant any product capable of dispersing the monomers in water to facilitate their polymerization.
• US Pat. No. 4,025,709, US Pat. No. 4,560,478, US Pat. No. 4,360,462, EP No. 6,046,666, EP No. 2,059,463 and EP No. 2,089,463 describe the methods for synthesizing PVDF by aqueous emulsification of VDF and its polymerization, there are numerous surfactant formulations.
• the amount of surfactant introduced at the start or during polymerization may be between 0.01 and 5 parts per 100 parts of water present in the initial charge of the reactor.
• inorganic peroxides for example in the form of salts, such as potassium or sodium persulfate, may be mentioned.
• the amount of initiator may range from 0.002 to 0.2 parts per 100 parts of monomers consumed in the reaction.
• Various coreactants well known to those skilled in the art may also be added to these inorganic peroxides to increase their rate of decomposition or to lower their temperature of use.
• organic initiator optionally used to continue the reaction
• hydrocarbon peroxides such as di-tert-butylperoxide, di-cumylperoxide or benzoyl peroxide
• dialkyl percarbonates such as diethyl or di-so-propylpercarbonate
• peracids or peresters such as t-butyl perpivalate; t-amyl perpivalate or t-butyl peroxybenzoate.
• the transfer agent is meant any product that limits the molecular weight of the polymer while propagating the polymerization reaction.
• the amount of transfer agent depends essentially on its nature and the average molar mass desired for the polymer fraction obtained in its presence, which conditions the average viscosity of the final product.
• the transfer agent used represents from 0.01 to 5 parts per 100 parts of monomers consumed in the reaction.
• the proportion of very high molar mass chains can represent up to 50% the weight of the component A and it is advantageously between 20 to 50%, preferably from 25 to 45% inclusive.
• the PVDF homopolymer used in the context of the invention as component A has a melt flow index of less than or equal to 15 g / 10 min, advantageously less than or equal to 10 g / 10 min, and ideally less than or equal to 5 g / 10 min, according to ISO 1133 (230 ° C, 12.5 kg), in order to guarantee good mechanical strength properties.
• Component B is present in the composition at a mass content greater than 10%).
• the elastomeric copolymer is present in the composition in a mass proportion of more than 10 to 40%, advantageously 20 to 40%, preferably 25 to 35%, inclusive.
• the mass content of copolymer in the composition is greater than or equal to 11%, or 12%, or 13%, or 14%, or 15%, or 16%>, or 17%>, or 18%, or 19%, or 20%, or 21%, or 22%, or 23%, or 24%, or 25%, or 26%, or 27%, or 28%, or 29%, or 30%, or 31%, or 32%>, or 33%>, or 34%, or 35%, or 36% , or 37%, or 38%, or 39%.
• the mass content of copolymer in the composition is less than or equal to 39%, or 38%, or 37%, or 36%, or 35%, or 34%, or 33%.
• the proportion by weight of comonomer in the copolymer is greater than 25%.
• it is: greater than or equal to 26%, and / or less than or equal to 40%, preferably less than or equal to 37%.
• the mass proportion of HFP in the copolymer is greater than 25%.
• it is: greater than or equal to 26%, and / or less than or equal to 40%, preferably less than or equal to 37%.
• the mass proportion of HFP in the elastomeric copolymer is preferably estimated by nuclear magnetic resonance (NMR).
• NMR nuclear magnetic resonance
• the copolymer samples are dissolved in a 5 mm diameter NMR tube.
• the copolymer samples are dissolved in tetrahydrofuran-d8 (THF-d8) at 60 ° C.
• An amount of copolymer (about 10 mg) is placed in a tube and solvent is added to fill 5.5 cm of tube (about 0.75 mL solvent).
• a heating block is used to bring the samples to the desired temperature.
• the samples are heated for at least one hour until dissolution of the solid and disappearance of the gel.
• the tubes are returned to check for frost.
• the spectra are acquired on a Bruker Advance type spectrometer operated at 60 ° C. and are analyzed according to a method analogous to that described in "Composition and Sequence Distribution of Vinylidene Fluoride Copolymer and Terpolymer Fluoroelastomers". Determination by NMR spectroscopy and 19 F correlation With Some properties ". M. Pianca et al, Polymer, 1987, vol.28, 224-230. However, the integration of the group CF instead of the group CF3 is used.
• the elastomeric copolymer used for the preparation of the composition according to the invention is devoid of homopolymer.
• the copolymer can be manufactured by the method described in the publication by M. Pianca et al supra.
• elastomeric copolymer is meant, as defined by ASTM in Special Technical Publication No. 184, a material capable of being stretched at room temperature up to twice its own length and which once released after holding on for 5 minutes, resumes to within 10%, its initial length at the same time.
• the fluoroelastomers that may be used in the context of the invention may be chosen from true elastomers or polymeric resins serving as the basic constituent for obtaining true elastomers.
• Component C is a low molecular weight VDF homopolymer; it is present in the composition in a mass proportion ranging from 1 to 20%, in particular from 2 to 18% and preferably from 5 to 15%.
• the ratio of the apparent melt viscosities of the components A and C is greater than or equal to 5, in particular greater than or equal to 10 and preferably greater than or equal to 50. This ratio is less than 500, preferably less than 500. at 400.
• the apparent melt viscosities of components A and C are expressed in Pa.s and measured on a capillary rheometer at a temperature of 230 ° C. and a shear of 100s 1 .
• the composition according to the invention may comprise at least one additive and / or at least one filler and / or electrically conductive particles and / or inorganic or organic pigments or dyes.
• fillers non-limiting mention may be made of mica, alumina, talc, carbon black, graphenes, expended graphites, carbon nanotubes, glass fibers and calcium carbonate.
• UV stabilizers preferably with the exception of agents of the IRGANOX ® type
• flame retardants preferably with the exception of flame retardants, heat stabilizers, manufacturing auxiliaries (preferably with the exception of polyolefins and in particular ethylene-based polymers).
• the above compounds distinct from the FCTHM PVDF, the copolymer and the PVDF homopolymer of low mass, are present at a level of at most 20%, preferably at most 15%, or at 10%. not more than 7% or not more than 5% or not more than 3% or not more than 2% or not more than 1% (in mass proportion to total composition).
• the subject of the invention is also a process for the manufacture of the above composition, comprising mixing the PVDF homopolymer (component A), the elastomeric copolymer (B) and the low molecular weight PVDF homopolymer (component C).
• This manufacturing method comprises any method which makes it possible to obtain a homogeneous mixture of the various constituents. Among these methods, mention may especially be made of the mixture in the molten or dry state. More particularly, the composition according to the invention is prepared by melt blending of all the constituents, on a compounding tool such as a twin-screw extruder, a comalizer or an internal or roll mixer.
• the FCTHM PVDF homopolymer (component A) and the copolymer (component B) are in dry form during mixing, preferably in the form of powders.
• the above method comprises premixing components A and B in latex form (or emulsions), and then drying the premix in a powder.
• An alternative is to pre-mix the component A in latex form with the copolymer B in powder form (or vice versa), then to dry this type of premix into a powder.
• the component C in the form of powder or latex, as well as any additives may be incorporated into the compositions during the mixing of the PVDF and the copolymer, or else mixed with one or the other of these constituents prior to their mixing, or else during the premixing of the PVDF and the copolymer according to the pre-mixing techniques described above.
• composition according to the invention makes it possible to manufacture: - all types of pipes for the transport of gaseous or liquid products, in particular intended to transport gaseous products for the synthesis of chemicals or intended to transport individual consumer products, whether industrial or public,

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• Chemical & Material Sciences (AREA)
• General Engineering & Computer Science (AREA)
• Engineering & Computer Science (AREA)
• Medicinal Chemistry (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• Mechanical Engineering (AREA)
• Compositions Of Macromolecular Compounds (AREA)
• Rigid Pipes And Flexible Pipes (AREA)
• Organic Insulating Materials (AREA)
• Insulated Conductors (AREA)
• Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)

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• 2015
  • 2015-07-27 FR FR1557155A patent/FR3039559B1/fr active Active
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  • 2016-07-27 WO PCT/FR2016/051943 patent/WO2017017373A1/fr active Application Filing
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