Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K3/00—Use of inorganic substances as compounding ingredients
  • C08K3/02—Elements
  • C08K3/04—Carbon
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
  • B29C48/03—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion
  • B29C48/09—Articles with cross-sections having partially or fully enclosed cavities, e.g. pipes or channels
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K3/00—Use of inorganic substances as compounding ingredients
  • C08K3/01—Use of inorganic substances as compounding ingredients characterized by their specific function
  • C08K3/017—Antistatic agents
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/0008—Organic ingredients according to more than one of the "one dot" groups of C08K5/01 - C08K5/59
  • C08K5/0016—Plasticisers
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/16—Nitrogen-containing compounds
  • C08K5/17—Amines; Quaternary ammonium compounds
  • C08K5/18—Amines; Quaternary ammonium compounds with aromatically bound amino groups
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L77/00—Compositions of polyamides obtained by reactions forming a carboxylic amide link in the main chain; Compositions of derivatives of such polymers
  • C08L77/06—Polyamides derived from polyamines and polycarboxylic acids

Definitions

• the present invention relates to polyamide-based compositions which can be used in particular for the manufacture of monolayer or multilayer tubes and / or pipes in the field of transport and / or storage of hydrocarbons.
• carbon black is more particularly used because of its great commercial availability and its good performance.
• the resistivity changes little at first.
• the percolation threshold a critical rate of carbon black, called the percolation threshold
• the resistivity drops very suddenly until it reaches a relatively stable level (plateau area), where a further increase in the rate of carbon black does not modify hardly any resistivity.
• the technical bulletin "Ketjenblack EC - BLACK 94/01" from the company AKZO NOBEL indicates that a conductive and / or semiconductor carbon black is all the more effective - that is to say, it requires add little to the polymer to give it anti-static properties - as its structure is developed.
• the structure of a carbon black reflects the way in which the basic carbon particles, which constitute the carbon black, are arranged in aggregates, or even in agglomerates.
• the structure of a carbon black can be expressed by its Specific Surface (measured by the nitrogen adsorption method - BET method - according to standard ASTM D 3037-89), as well as by its DBP absorption (di-butyl -phthalate) (measured according to ASTM D 2414-90).
• the carbon blacks marketed by the company AKZO NOBEL are very structured and characterized by a BET surface and a high DBP absorption. They are often referred to as extra conductive carbon blacks. Thanks to their developed structure, the percolation threshold is reached for a low addition rate.
• carbon black behaves like a filler, such as, for example, talc, chalk, kaolin, and therefore affects many other physical and chemical properties.
• the Applicant Company thus found that, for polyamide 12, with an inherent viscosity 1.65 (measured at 20 ° C for a sample of 0.5 g in 100 g of metacresol), plasticized with 11.4% by mass of n-butyl benzene sulfonamide (BBSA), and containing at least 6% by mass of carbon black Ketjenblack EC 600 JD from the company AKZO NOBEL (characterized by a DBP absorption greater than 400 ml / g and by a BET surface area greater than 1000 m 2 / g), the surface resistivity on the tube is less than 10 6 ohms. It also noted, for this same polyamide, that the plateau area (10 2 -10 3 ohms) is reached from 10% by mass of carbon black Ketjenblack EC 600 JD.
• BBSA n-butyl benzene sulfonamide
• the present invention residing in the choice of this "less structured" carbon black, does not achieve a better compromise antistatic / other properties, but leads to an antistatic composition based on polyamide having i ni-.ri n ⁇ èqupm nf- . better rheological and resilience properties.
• the present invention therefore firstly relates to an antistatic polyamide composition, comprising at least one polyamide and a sufficient amount of carbon black to make it antistatic, characterized in that the carbon black is at least one carbon black chosen from those having a BET specific surface, measured according to standard ASTM D 3037-89, from 5 to 200 m 2 / g; in particular from 20 to 100 m 2 / g, and a DBP absorption, measured according to standard ASTM D 2414-90, from 50 to 300 ml / 100 g, in particular from 125 to 250 ml / 100 g.
• the carbon blacks according to the invention can be qualified as conductors or semiconductors, unlike the extra-conductive carbon blacks used in accordance with the prior art, which generally have a BET surface of more than 500 m 2 / g and an absorption DBP greater than 300 ml / 100 g.
• polyamide-based antistatic compositions of the invention preferably contain from 16 to 30% by mass of these “less structured” carbon black (s) or semiconductor (s), and more particularly from 17.5 to 23% by mass, relative to the total composition.
• polyamide-based antistatic compositions of the prior art using "more structured" extra-conductive carbon blacks, for their part generally contain from 4 to 14% by mass, and more particularly from 6 to 10% by mass, for achieve the same level of antistatism.
• the antistatic compositions according to the invention exhibit better fluidity and better impact resistance, as will be illustrated by the Examples below.
• polyamide within the meaning of the present invention is meant polyamides or PAs which contain aliphatic and / or cycloaliphatic and / or aromatic units.
• polyamides obtained by polycondensation of one or more lactams, of ⁇ , ⁇ -amino acids or by a substantially stoichiometric polycondensation of one or more aliphatic diamine (s) and of one or more diacid (s) ) aliphatic carboxylic (s).
• An excess of diamine can be used so as to obtain an excess of amino end groups relative to the carboxyl end groups in the polyamide.
• the lactams contain at least 6 carbon atoms, preferably at least 10.
• the preferred lactams are decalactam, 1 undecalactam, dodecalactam.
• the preferred ⁇ , ⁇ -amino acids are 10-aminodecanoic, 11-aminoundecanoic, 12-aminododecanoic.
• the aliphatic diamines are ⁇ , ⁇ -diamines containing between the terminal amino groups at least 6 carbon atoms, preferably from 6 to 10.
• the carbon chain can be linear (polymethylenediamine) or branched or cycloaliphatic.
• Preferred diamines are hexamethylenediamine (HMDA), dodecamethylenediamine, decamethylenediamine.
• the dicarboxylic acids can be aliphatic, cycloaliphatic or aromatic.
• the aliphatic dicarboxylic acids are ⁇ , ⁇ -dicarboxylic acids having at least 4 carbon atoms (not including the carbon atoms of the carboxylic groups), preferably at least 6, in the linear or branched carbon chain.
• the diacids are azelaic, sebacic and 1,12-dodecanoic acids.
• PA-6 polyhexamethylenesbacamide
• PA-6,12 polyhexamethylenedodecanediamide
• PA-11 poly (undecanoamide)
• PA-12 polylauryllactam
• PA-12 polydodecamethylenedodecanediamide
• PA-6 polycapronamide
• PA-6 polyhexamethyleneadipamide
• PAs have a number average molecular weight generally greater than or equal to 5000. Their inherent viscosity (measured at 20 ° C. for a sample of
• 0.5 g in 100 g of meta-cresol is generally greater than 0.7.
• PA within the meaning of the present invention, is also meant mixtures of polymers containing at least 50% by weight of the polyamides described above where the matrix phase consists of polyamide.
• mixtures By way of example of mixtures, mention may be made of mixtures of aliphatic polyamides and semi-polyamides aromatic and / or amorphous, such as those described in EP 550308, as well as PA-polyolefin blends and in particular those described in EP 342066.
• thermoplastic elastomers based on polyamide which are block copolymers, also called polyether or polyetherblocamides, the rigid blocks of which consist of polyamide and the flexible crystallizable blocks of polyether.
• the compositions according to the invention may also contain at least one additive chosen from: plasticizers; shock additives; phosphoric, phosphorous or hydrophosphorous acid or their esters or sodium or potassium salts or combinations of these products; dyes; pigments, other than carbon black; brighteners; - antioxidants; UV stabilizers; chain limiters; and reinforcing fillers.
• the plasticizers can be any plasticizers known in the field of polyamides, and are in particular chosen from benzene sulfonamide derivatives, such as n-butyl benzene sulfonamide (BBSA) ("Ucemid A"), ethyl toluene sulfonamide ("Santicizer 8") or N-cyclohexyl toluene sulfonamide (“Santicizer 1H”); esters of hydroxy benzoic acids, such as 2-ethylhexyl parahydroxybenzoate (EHPB) and 2-decyl hexyl parahydroxybenzoate (DHPB); lactams, such as caprolactam and N-methyl-pyrrolidone; esters or ethers of tetrahydrofurfuryl alcohol, such as
• Oligoethyleneoxytetrahydrofurfuryl alcohol and esters of citric acid or hydroxy-malonic acid, such than 1 oligoethyleneoxy malonate.
• a particularly preferred plasticizer is n-butyl benzene sulfonamide (BBSA).
• Shock additives the amount of which can be up to 40% by mass relative to the total composition are, for example:
• polyolefins which can be defined as polymers comprising olefin units, such as, for example, ethylene, propylene, butene-1 units or any other alpha olefin; by way of examples, mention may be made of: polyethylenes, such as LDPE, HDPE, LLDPE or VLDPE; - polypropylene; ethylene / propylene copolymers; PE, in particular VLDPE, obtained with a metallocene as catalyst; copolymers of ethylene with at least one product chosen from salts or esters of unsaturated carboxylic acids, or vinyl esters of unsaturated carboxylic acids.
• LLDPE low density polyethylene
• VLDPE polypropylene
• ethylene / vinyl acetate copolymers ethylene / alkyl (meth) acrylate copolymers
• the density of the polyolefin may advantageously be between 0.86 and 0.965, and its MFI may be between 0.3 and 40,
• block copolymers such as ethylene-propylene rubber copolymers (EPR), styrene-b-butadiene-j-styrene copolymers (SBS), styrene-jb-isoprene-1 "-styrene copolymers, ethylene-b-propylene-jb-diene copolymers (EPDM), ethylene-jb-propylene-jb-butadiene or isoprene copolymers, styrene-jb-ethylene-butene -h-styrene copolymers
• EPR ethylene-propylene rubber copolymers
• SBS styrene-b-butadiene-j-styrene copolymers
• EPDM ethylene-jb-propylene-jb-butadiene or isoprene copolymers
• SEBS such as the copolymer sold under the name "KRATON” by the company Shell
• 3) functionalized polyolefins which can be defined as polymers comprising alpha-olefin units and epoxide or carboxylic acid or carboxylic acid anhydride units.
• copolymers of ethylene, of an unsaturated epoxide and optionally of an ester or a salt of unsaturated carboxylic acid or of a vinyl ester of saturated carboxylic acid are, for example, ethylene / vinyl acetate / glycidyl (meth) acrylate copolymers or ethylene / (meth) alkyl acrylate / (meth) glycidyl acrylate copolymers; as examples of the latter, mention may be made of those marketed under the name
• Li / maleic anhydride polyethylene, polypropylene, grafted ethylene propylene copolymers or copolymerized with an unsaturated carboxylic acid anhydride and then condensed with a polyamide (or a polyamide oligomer) monoamine.
• the functionalized polyolefin is chosen from ethylene / vinyl acetate / maleic anhydride copolymers, ethylene / propylene copolymers predominantly in propylene grafted with maleic anhydride and then condensed with monoamino polyamide 6 or monoamino oligomers of caprolactam.
• the alkyl groups of the alkyl acrylate or methacrylate entering these terpolymers can be linear, branched or cyclic, and contain up to 10 carbon atoms; as examples of alkyl (meth) acrylate used in the composition of these terpolymers, mention may be made of methyl acrylate, ethyl acrylate, n-butyl acrylate, acrylate isobutyl, 2-ethylhexyl acrylate, cyclohexyl acrylate, ethyl methacrylate, and most particularly ethyl acrylate, n-butyl acrylate and methyl acrylate; as examples of anhydrides of unsaturated dicarboxylic acids falling within the definition of these co- or terpolymers, there may be mentioned itaconic anhydride, citraconic anhydride, anhydride 2-methyl-maleic, 2,3
• pigments examples include titanium dioxide, cobalt oxide, iron oxide, nickel titanate, organic pigments such as phthalocyanine and anthraquinone derivatives.
• Antioxidants are, for example, copper iodide combined with potassium iodide, derivatives of hindered phenols and hindered amines.
• UV stabilizers there may be mentioned resorcinol derivatives, benzotriazoles or salicylates.
• chain limiters monocarboxylic or dicarboxylic acids or monoamines or aliphatic diamines can be used.
• reinforcing fillers are wollastonite, glass beads, kaolin, talc, mica, the mixture of quartz, mica and chlorite known as "plastorite", calcium and / or magnesium carbonate, glass fibers, boron nitride fibers, carbon fibers.
• the compositions according to the invention can be obtained in a known manner by any technique of mixing the constituents in the molten state such as, for example, extrusion or compounding on a single or double extruder screw, on co-mixer or by any continuous or discontinuous technique, such as for example using an internal mixer.
• the present invention also relates to the methods of transformation of said compositions, as well as to the articles obtained.
• the articles obtained can be tubes, films, pipes, plates, fibers, etc. These materials or articles can be monolayers or multilayers. In the case of multilayer materials or articles, the layer most exposed to the accumulation of electrostatic charges will be based on a composition according to the invention.
• the invention makes it possible in particular to have available mono- or multilayer anti-static and impact-resistant tubes for transporting and / or storing hydrocarbons and in particular petrol.
• extrusion and coextrusion techniques are used in the thermoplastics industry which are suitable for the production of articles.
• Polyamide compositions are respectively prepared, non-antistatic (reference composition), antistatic (comparative composition) and antistatic (composition of the invention), respectively, having the formulations given in Table 1.
• Table 1 Table 1
• Example 1 To prepare the composition of Example 1, the granules of plasticized polyamide modified with polyetherblocamide are introduced into the feed hopper of an extruder of the comalaxer type.
• the extrusion material temperatures are typically of the order of 240 to 270 ° C.
• the flow rate is 15 to 20 kg / h.
• the carbon black is introduced into the molten zone using a feeding hopper on an extruder of the BUSS co-kneader type, the granules of plasticized polyamide, modified by polyetherblocamide, being partly introduced into the feed hopper, partly with carbon black.
• the temperatures of the extrusion material are typically of the order of 240 to 270 ° C.
• the flow rate is 15 to 20 kg / h.
• melt index (MFI) of each of the compositions of Examples 1 to 3 is measured (in g / 10 min) at 235 ° C. under 10 kg (Standard ISO 1133: 91).
• the tested samples contain less than 0.1% moisture.
• compositions of Examples 1 to 3 are extruded in the form of single-layer tubes with an internal diameter of 6 mm and an external diameter of 8 mm, on a single-screw extruder equipped with a screw with a diameter of 45 mm, suitable for the extrusion of polyamides at temperatures from 210 to 250 ° C.
• Cylindrical copper electrodes are introduced at the ends of a 100 mm long tube. A suitable voltage is applied to these electrodes and the current is measured. Resistance as well measured (gross measurement) is then multiplied by the internal circumference of the tube, then divided by the distance between electrodes; we obtain the surface resistivity which is expressed in ohm ( ⁇ ).
• compositions of Examples 1 to 3 are injected on the press in the form of plates at temperatures of 250 to 270 ° C. These plates have the following dimensions: 100 x 100 x 2 mm and allow multiaxial impact tests to be carried out at a speed of 4.3 m / s. In this test, the total energy absorbed (in Joules) by the composition is measured during the impact. We also note the type of rupture facies: fragile or ductile. These tests are carried out at -30 ° C. The plates are conditioned 15 days at 50% relative humidity before being tested.
• compositions of Examples 1 to 3 are extruded in the form of tubes as indicated for the measurement of surface resistivity.
• a mass of 0.912 kg hits a tube perpendicularly from a height of 305 mm.
• a tube passes the test if it retains, after impact, a burst strength (burst pressure) greater than 70% of the burst pressure of an un impacted tube. Otherwise, the tube is considered to break.
• the tubes are tested at -40 ° C.
• the tubes are conditioned 15 days at 50% relative humidity before being tested.

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• Chemical & Material Sciences (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Compositions Of Macromolecular Compounds (AREA)
• Laminated Bodies (AREA)
• Rigid Pipes And Flexible Pipes (AREA)
• Pigments, Carbon Blacks, Or Wood Stains (AREA)

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• 1997
  • 1997-12-23 FR FR9716406A patent/FR2772776B1/fr not_active Expired - Lifetime
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