Classifications

• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
  • D01F6/00—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof
  • D01F6/88—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from mixtures of polycondensation products as major constituent with other polymers or low-molecular-weight compounds
  • D01F6/90—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from mixtures of polycondensation products as major constituent with other polymers or low-molecular-weight compounds of polyamides
• • 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
• • 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 a process for manufacturing polyamide-based yarns, fibers and filaments, and also to the yarns, fibers and filaments that may be obtained by the process.
• Polyarnide-based yarns, fibers and filaments are produced by melt-spinning a polyamide or a polyamide-based composition. Melt-spinning consists in extruding the polyamide or the composition through dies and in cooling at the die outlets. Articles intended for use in many fields are thus manufactured. Examples that may be mentioned include multifilament yarns for the textile industry, fibers intended to be processed by spinning, or for the manufacture of nonwoven articles, cables intended to be chopped to form short fibers that may be flocked, and monofilaments and multifilaments for specific applications, especially industrial applications.
• This drawing step is also carried out for the manufacture of monofilaments. Furthermore, depending on the applications, a drawing operation may be applied to all the types of yarns obtained by the processes described above. Thus, the yarns obtained by the POY processes are very often drawn either directly on leaving the spinning process (integrated drawing), or in a separate step comprising an uptake of the yarns.
• document FR 2 677 376 describes the addition of nanometer-sized mineral particles. The presence of these particles allows the spinning speeds to be increased. However, it is difficult to obtain a good dispersion of the particles, to the extent that the level of breaks during spinning may be large.
• One object of the present invention is to propose a process for manufacturing yarns, fibers and filaments based on a polyamide composition having a molecular structure that makes it possible to improve the total production efficiency of the spinning process, especially by improving the drawability of the yarns produced, thus making it possible to have, for example, for an identical spinning speed, a much higher metreage of yarns per unit of time produced after spinning.
• the invention proposes a process for manufacturing synthetic, polyamide-based yarns, fibers and filaments, comprising the following operations:
• compound A a linear polyamide
• compound B chosen from the group comprising:
• a polyamide or a polyamide composition comprising:
• starburst or H-shaped macromolecular chains comprising one or more cores and at least three polyamide branches or three polyamide segments linked to the said core, obtained from amino acid and/or lactam monomers,
• melt flow index of the polyamide or of the polyamide composition measured according to ISO standard 1133 at 275° C. under a 100 g charge being greater than 20 g/10 min
• the term “spinning” means the operation consisting in extruding the material in melt form through dies and then in cooling it between the dies and at least one first point of entrainment.
• the expression “process for manufacturing yarns, fibers and filaments” means the combination of steps leading to yarns, fibers and filaments.
• the process especially comprises the spinning operation. It may comprise other operations carried out after the spinning operation, including a drawing step (in continuous mode or in repeat mode), making it possible to improve the mechanical properties of the spun products and to obtain, for example, a rupture modulus and a residual elongation at break that are compatible with the processes for using these products and the processes for treating them.
• Processes for treating the spun products that may be mentioned include relaxing, curling, texturing, heat-setting and dyeing treatments.
• the process according to the invention comprises an operation of melt-blending at least two compounds, a compound A and a compound B.
• the two compounds are thermoplastic.
• the blend may be obtained by any means conventionally used for producing a blend of two thermoplastic compounds, for example a single-screw or twin-screw and/or a barrier-screw extrusion device. It is possible, for example, to add granules of compound B to compound A in melt form, or to mix together granules of compound A and of compound B and to melt the blend of granules.
• additives such as pigments, delustring agents, dull-spinning agents, catalysts, heat and/or light stabilizers, antibacterial agents and antifungal agents. It may be, for example, a dull-spinning agent chosen, for example, from titanium dioxide or zinc sulphide particles.
• the melt-blending may be followed by a solidification and a granulation.
• the solid blend is then remelted for the spinning operation.
• the melt-blending operation is directly followed by the spinning operation, without intermediate solidification and granulation.
• the blend of compounds is melt-spun. This operation is performed by extrusion through dies, at a suitably selected temperature and pressure. All the known spinning devices may be used.
• compound A is a linear polyamide or a composition based on a linear polyamide.
• polyamides that may be used, mention may be made of polyamides of the type obtained from lactams and/or from amino acids. Mention is made in particular of nylon-6, nylon-11 and nylon-12, and blends and copolymers based on these polyamides.
• the linear polyamides may be used for the blending operation in pure form, or in the form of a composition with, for example, one of the additives mentioned above.
• compound A is a linear polyamide, or a composition based on a linear polyamide obtained from a diacid monomer and a diamine monomer.
• diacid monomers include adipic acid, which is the preferred acid, decanoic acid or sebacic acid, dodecanoic acid, and phthalic acids such as terephthalic acid and isophthalic acid.
• Diamine monomers include hexamethylene-diamine, methylpentamethylenediamine, 4,4′-diaminodicyclohexylmethane, butanediamine and meta-xylylenediamine.
• the polyamides obtained from these monomers are especially nylon-6,6 (polyhexamethylenediamine adipate), nylon-4,6 and nylon-6, 12.
• the linear polyamides that are suitable for the invention are also copolyamides comprising at least 90 mol % of repeating units corresponding to the polyamides described above, the other repeating units possibly originating from diacid, diamine, amino acid or lactam monomers.
• Copolyamides that may especially be mentioned include nylon-6,6/6 containing less than 5 mol % of nylon-6 units.
• the polyamides that are suitable for the invention may also comprise a monofunctional monomer conventionally used in the production of these polymers, as a chain-limiter.
• Compound B is, in a first embodiment of the invention, a polymer or a polymer composition comprising starburst or H-shaped macromolecular chains and, where appropriate, linear macromolecular chains.
• Polymers or polymer compositions comprising such starburst or H-shaped macromolecular chains are described, for example, in documents FR 2 743 077, FR 2 779 730, U.S. Pat. No. 5,959,069, EP 0 632 703, EP 0 682 057 and EP 0 832 149. These compounds are known to have an improved melt index when compared with linear polyamides.
• the melt index of compound B used in the context of the invention measured according to ISO standard 1133 at 275° C. under a 100 g load, is greater than 20 g/10 min.
• the starburst or H-shaped macromolecular chains are obtained by using a multifunctional compound containing at least three reactive functions, all the reactive functions being identical.
• This compound may be used as a comonomer in the presence of other monomers in a polymerization process. It may also be placed in contact with a polyamide during an extrusion operation.
• the starburst or H-shaped macromolecular chains comprise a core and at least three polyamide branches.
• the branches are linked to the core via a covalent bond, by means of an amide group or group of another nature.
• the core is an organic or organometallic chemical compound, preferably a hydrocarbon-based compound optionally comprising hetero atoms and to which the branches are linked.
• Branches are polyamide chains. They may show branching, and this is especially the case for the H-shaped structures.
• the polyamide chains constituting the branches are preferably of the type obtained by polymerization of lactams or amino acids, for example of nylon-6 type.
• Compound B optionally comprises, in addition to the starburst or H-shaped chains, linear polyamide macromolecular chains.
• the weight ratio between the amount of starburst or H-shaped chains in compound B and the sum of the amounts of starburst or H-shaped chains and of linear chains is between 0.1 and 1, limits included. It is preferably between 0.5 and 1.
• compound B is a starburst polyamide, that is to say a polyamide comprising starburst macromolecular chains, obtained by copolymerization using a monomer blend comprising:
• a multifunctional compound comprising at least three reactive functions chosen from amines, carboxylic acids and derivatives thereof, all the reactive functions being identical,
• R 2 and R 3 which may be identical or different, represent substituted or unsubstituted, aliphatic, cycloaliphatic or aromatic hydrocarbon-based radicals containing from 2 to 20 carbon atoms, and possibly comprising hetero atoms,
• Y is a primary amine radical when X represents a carboxylic radical
• Y is a carboxylic radical when X represents a primary amine radical.
• the polymerization (polycondensation) reaction is advantageously carried out until the thermodynamic equilibrium is reached.
• the monomer blend can comprise other compounds, such as chain limiters, catalysts or additives.
• T 0 represents the number of moles of multifunctional compound
• N 0 represents the initial number of moles of monomer of formula (IIa) or (IIb)
• R R 0 represents the initial number of moles of monomer of formula (III)
• T 0 represents the number of moles of multifunctional compound
• N 0 represents the initial number of moles of monomer of formula (IIa) or (IIb)
• R 0 represents the initial number of moles of monomer of formula (III)
• compound B is an H-shaped polyamide, that is to say a polyamide comprising H-shaped macromolecular chains, obtained by copolymerization using a monomer blend comprising:
• the sum of the functional groups of c) and d) being between 1.5 and 0.66, the ratio in equivalents between the functional groups of c) and the functional groups of d) being between 0.17 and 1.5.
• compound B is obtained by melt-blending, for example using an extrusion device, of a polyamide of the type obtained by polymerization of lactams and/or of amino acids, and of a multifunctional compound comprising at least three identical reactive functions chosen from amine and carboxylic acid functions.
• the polyamide is, for example, nylon-6.
• compound B is a multifunctional compound such as those used as the core for the synthesis of the starburst polyamides and/or H-shaped polyamides described above and below. This compound is added directly to compound A in the melt in a manner similar to the processes for introducing the compounds B of starburst polyamide or H-shaped polyamide type.
• the multifunctional compounds used may be chosen from compounds with an arborescent or dendritic structure. They may also be chosen from the compounds represented by formula (I):
• R 1 is a linear or cyclic, aromatic or aliphatic hydrocarbon-based radical containing at least two carbon atoms and possibly comprising hetero atoms,
• A is a covalent bond or an aliphatic hydrocarbon-based radical containing from 1 to 6 carbon atoms
• Z represents a primary amine radical or a carboxylic group
• m is an integer between 3 and 8.
• the radical R 1 is either a cycloaliphatic radical such as a tetravalent cyclohexanonyl radical, or a 1,1,1 -triylpropane or 1,2,3-triylpropane radical.
• radicals R 1 that are suitable for the invention, mention may be made, for example, of substituted or unsubstituted trivalent phenyl and cyclohexanyl radicals, tetravalent diaminopolymethylene radicals with a number of methylene groups advantageously of between 2 and 12, such as the radical derived from EDTA (ethylenediaminetetraacetic acid), octavalent cyclohexanonyl or cyclohexadinonyl radicals, and radicals derived from compounds obtained from the reaction of polyols such as glycol, pentaerythritol, sorbitol or mannitol, with acrylonitrile.
• EDTA ethylenediaminetetraacetic acid
• octavalent cyclohexanonyl or cyclohexadinonyl radicals radicals derived from compounds obtained from the reaction of polyols such as glycol, pentaerythritol,
• the radical A is preferably a methylenic or polymethylenic radical such as ethyl, propyl or butyl radicals, or a polyoxyalkylenic radical such as a polyoxyethylenic radical.
• the number m is greater than 3 and advantageously equal to 3 or 4.
• the reactive function of the multifunctional compound represented by the symbol X—H is a function capable of forming an amide function.
• polyfunctional compounds of formula I examples include 2,2,6,6-tetra( ⁇ -carboxyethyl)cyclohexanone, diaminopropane-N,N,N′,N′-tetraacetic acid of the following formula:
• R 1 represents a 1,1,1-triylpropane or a 1,2,3-triylpropane radical
• A represents a polyoxyethylenic radical.
• nitrilotrialkylamines in particular nitrilotriethylamine, dialkylenetriamines, in particular diethylenetriamine, trialkylenetetramines and tetraalkylenepentamines, the alkylene preferably being ethylene or 4-aminoethyl-1,8-octanediamine. Mention is also made of the dendrimers of formula (II)
• R is a hydrogen atom or a group —(CH 2 ) n —NR 1 2 in which
• R 1 is a hydrogen atom or a group —(CH 2 ) n —NR 2 2 in which
• R 2 is a hydrogen atom or a group —(CH 2 ) n —NR 3 2 in which
• R 3 is a hydrogen atom or a group —(CH 2 ) n —NH 2 ,
• n being an integer between 2 and 6
• x being an integer between 2 and 14.
• n is preferably an integer equal to 3 or 4, in particular 3, and x is preferably an integer between 2 and 6 (limits included), preferably equal to 2, 3 or 4 and in particular 2.
• Each radical R may be chosen independently of the others.
• the radical R is preferably a hydrogen atom or a group —(CH 2 ) N —NH 2 .
• multifunctional compounds containing 3 to 10 and preferably 3 or 4 carboxylic acid groups are also made.
• the ones that are preferred are compounds containing an aromatic and/or heterocyclic ring, for example benzyl, naphthyl, anthracenyl, biphenyl and triphenyl radicals, or heterocycles, for instance pyridine, bipyridine, pyrrole, indole, furan, thiophene, purine, quinoline, phenanthrene, porphyrine, phthalocyanine and naphthalocyanine.
• an aromatic and/or heterocyclic ring for example benzyl, naphthyl, anthracenyl, biphenyl and triphenyl radicals, or heterocycles, for instance pyridine, bipyridine, pyrrole, indole, furan, thiophene, purine, quinoline, phenanthrene, porphyrine, phthalocyanine and naphthalocyanine.
• 3,5,3′,5′-Biphenyltetracarboxylic acid acids derived from phthalocyanine and from naphthalocyanine, 3,5,3′,5′-biphenyltetracarboxylic acid, 1,3,5,7-naphthalenetetracarboxylic acid, 2,4,6-pyridinetricarboxylic acid, 3,5,3′,5′-bipyridyltetracarboxylic acid, 3,5,3′,5′-benzophenonetetracarboxylic acid and 1,3,6,8-acridinetetracarboxylic acid are most particularly preferred, and even more particularly trimesic acid and 1,2,4,5-benzenetetracarboxylic acid.
• TTAC 1,3,5-triazine-2,4,6-triaminocaproic acid
• the weight proportion of compound B relative to the weight of compounds A and B in the blend is advantageously less than 30%, preferably less than 20% and even more preferably less than 15%. According to this characteristic, no account is taken of the possible presence of other additives.
• the yarns, fibers and filaments obtained from the blend of compounds A and B comprise starburst or H-shaped polyamide macromolecular chains and linear polyamide chains.
• the weight proportion of the starburst or H-shaped macromolecular chains relative to the total weight of the starburst or H-shaped and linear macromolecular chains is preferably less than 25% and even more preferably less than 15%.
• the process according to the invention can be used in the context of a high-speed spinning process, for example at speeds above 3 500 m/min, of POY, HOY or FEI type, for the manufacture of multifilament yarns, or in the LOY process for the manufacture of fibers.
• the yarns obtained have, surprisingly, a drawability that is greater than that observed with the yarns obtained from linear polyamide conventionally used, such as nylon-6,6 for mechanical properties that are comparable and compatible with the use of these products in the various applications such as the textile industry.
• the products obtained according to the process of the invention have a rupture modulus and a residual elongation at break equivalent to those shown by nylon-6,6 yarns.
• This improved drawability thus makes it possible to improve production efficiency of the process for manufacturing yarns either by increasing the spinning speed or by increasing the draw ratio applied to the yarns obtained or by applying these two increases.
• the process of the invention makes it possible to manufacture yarns, fibers or monofilaments with application of a global draw ratio, the draw ratio applied to the spinning plus the draw ratio applied during the drawing step, that is higher than that which may be applied to linear polyamide yarns, for the same level of rupture modulus and elongation at break for the yarn thus obtained.
• the process of the invention also makes it possible to produce, by melt-spinning and drawing, yarns with a very fine yarn count, for example of less than 0.8 dtex and preferably less than 0.6 dtex. Specifically, it is possible according to the process of the invention to produce yarns at the die outlet with a fine yarn count, in a manner similar to that obtained with a linear polyamide, and with a similar device. However, since it is possible to apply a higher draw ratio to the yarns obtained by the process of the invention, it is easy to understand that the final yarn count of the yarn according to the invention is markedly lower for equivalent mechanical properties. This possibility is especially very advantageous for the manufacture of fibers with a very small yarn count.
• the process according to the invention can be used in the context of a manufacture of yarns, fibers and filaments starting with a linear polyamide of high molecular mass.
• These polyamides are generally used to obtain improved mechanical properties and/or improved chemical resistance or heat resistance properties, for instance abrasion resistance. It is in particular adapted to the manufacture of fibers for felts for paper machines.
• the use of compound B makes it possible to spin at a lower temperature and/or at lower pressure compared with the conditions that would be necessary in the absence of the compound. It is thus possible either to obtain yarns that are more resistant to abrasion since the molecular mass of the polyamide is higher, or to obtain fibers whose properties are similar, with a less restrictive process.
• the linear polyamide is a nylon-6 whose relative viscosity, measured at 25° C. at a concentration of 0.01 g/ml in a 96% sulphuric acid solution, is greater than 3.5 and preferably greater than 3.8.
• these compounds are introduced in dried form, preferably with a moisture content of less than 0.3%, and a compound capable of catalysing the polycondensation of the polyamide is added, preferably in a weight concentration of between 0.005% and 5%.
• This compound may be chosen from phosphorus compounds, for example phosphoric acid or tris(2,4-di-tert-butylphenyl) phosphite (sold by the company CIBA under the reference Irgafos 168, or as a blend with N,N-hexamethylenebis(3,5-di-tert-butyl-4-hydroxyhydrocinnamide) under the reference Irganox B 1171).
• This compound may be added in the form of powder or in the form of concentrate to a polyamide matrix (masterbatch). The blending of the various compounds is carried out in a single-screw or twin-screw extrusion device.
• the spinning is generally carried out at moderate speed, of less than 1 000 m/min, with a subsequent drawing operation.
• Compound A nylon-6,6 with a viscosity index of 136 ml/g, measured at 25° C. at a concentration of 0.01 g/ml in a 90% formic acid solution, with a concentration of acid end functions (GTA) of 55 meq/g of polymer and a concentration of amine end functions (GTC) of 66 meq/g of polymer.
• GTA acid end functions
• GTC concentration of amine end functions
• Compound B starburst polyamide, obtained by copolymerization using caprolactam in the presence of 0.5 mol % of 2,2,6,6-tetra(carboxyethyl)cyclohexanone, according to a process described in document FR 2 743 077, comprising about 80% of starburst macromolecular chains and 20% of linear macromolecular chains, with a viscosity index of 98.2 ml/g measured according to the method described above and a GTA of 13.9 meq/g and a GTC of 165.3 meq/g, and a melt index in the melt, measured at 275° C. under 100 g, of 55 g/10 minutes.
• Compound C nylon-6 with a relative viscosity, measured at 25° C. at a concentration of 0.01 g/ml in a 96% sulphuric acid solution, of about 3.8, sold by the company BASF under the reference B4000.
• the elongation at break and breaking stress properties of the yarns are determined on an Erichsen tensile testing machine placed in an air-conditioned room at 50% RH and 23° C. after conditioning the yarns for 72 hours under these conditions.
• the initial length of the yarns is 50 mm and the running speed is 50 mm/min.
• the compounds are melt-blended using a single-screw extrusion device and the melt is then spun, with a speed at the first point of call, also known as the spinning speed, of 4 200 m/min, so as to obtain a continuous yarn comprising 34 filaments with a total yarn count indicated in Table I below.
• the spinning conditions are collated in Table I below, the properties of the yarns obtained being collated in Table II. TABLE I Flow Die rate of temper- Spinning polymer Spinning Composition ature pressure in the speed Ex.
• the compounds are melt-blended using a twin-screw extrusion device and the melt is then spun, with a speed at the first point of call of 3 300 m/min, so as to obtain a continuous multifilament yarn of 55 dtex per 10 filaments.
• the temperature, pressure and spinning rate, and also the properties of the yarns obtained, are specified in Table IV.
• a yarn is prepared as in Example 5, using compound C alone.
• the temperature, pressure and spinning rate, and also the properties of the yarns obtained, are specified in Table IV.
• TABLE IV Example 5 Comparative Example 6 Compound C 80% 100% Compound B 20% Spinning temperature 285° C. 320° C. Spinning rate Few breaks Very large number of breaks Pressure in the die 150 bar 150 bar Elongation at break (%) 95 95 Breaking stress (cN/tex) 25 25
• the present invention relates to a process for manufacturing polyamide-based yarns, fibers and filaments, and also to the yarns, fibers and filaments that may be obtained by the process.
• the present invention relates to a process for manufacturing yarns, fibers and filaments based on a polyamide composition having a molecular structure that makes it possible to improve the total production efficiency of the spinning process, especially by improving the drawability of the yarns produced, thus making it possible to have, for example, for an identical spinning speed, a much higher metreage of yarns per unit of time produced after spinning.
• the invention consists of a process for manufacturing synthetic, polyamide-based yarns, fibers and filaments, comprising the following operations:
• compound A a linear polyamide
• compound B chosen from the group comprising:
• a polyamide or a polyamide composition comprising:
• starburst or H-shaped macromolecular chains comprising one or more cores and at least three polyamide branches or three polyamide segments linked to the said core, obtained from amino acid and/or lactam monomers,
• linear polyamide macromolecular chains obtained from amino acid and/or lactam monomers
• melt flow index of the polyamide or of the polyamide composition measured according to ISO standard 1133 at 275° C. under a 100 g charge being greater than 20 g/10 min

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Textile Engineering (AREA)
• Engineering & Computer Science (AREA)
• Medicinal Chemistry (AREA)
• Organic Chemistry (AREA)
• Polymers & Plastics (AREA)
• Health & Medical Sciences (AREA)
• Compositions Of Macromolecular Compounds (AREA)
• Polyamides (AREA)
• Artificial Filaments (AREA)
• Yarns And Mechanical Finishing Of Yarns Or Ropes (AREA)

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