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
  • D01F1/00—General methods for the manufacture of artificial filaments or the like
  • D01F1/02—Addition of substances to the spinning solution or to the melt
  • D01F1/09—Addition of substances to the spinning solution or to the melt for making electroconductive or anti-static filaments
• • 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
  • D01F8/00—Conjugated, i.e. bi- or multicomponent, artificial filaments or the like; Manufacture thereof
  • D01F8/04—Conjugated, i.e. bi- or multicomponent, artificial filaments or the like; Manufacture thereof from synthetic polymers
  • D01F8/12—Conjugated, i.e. bi- or multicomponent, artificial filaments or the like; Manufacture thereof from synthetic polymers with at least one polyamide as constituent
• • 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
  • D01F8/00—Conjugated, i.e. bi- or multicomponent, artificial filaments or the like; Manufacture thereof
  • D01F8/04—Conjugated, i.e. bi- or multicomponent, artificial filaments or the like; Manufacture thereof from synthetic polymers
  • D01F8/14—Conjugated, i.e. bi- or multicomponent, artificial filaments or the like; Manufacture thereof from synthetic polymers with at least one polyester as constituent

Definitions

• the present invention relates to conductive dirt-repellent core-sheath fibers, in particular monofilaments, which can be used in particular in technical fabrics.
• melt-spinnable fluoropolymers have good thermal stability, good chemical resistance and dirt-repellent properties. Attempts have already been made to process melt-spinnable fluoropolymers into fibers, multi- and monofilaments in order to use them to produce textile surfaces for technical applications with the above-mentioned properties of fluoropolymers.
• a disadvantage of melt-spinnable fluoropolymers is the high creep behavior. Fibers and filaments made from this material therefore have only low tensile strengths and are not dimensionally stable.
• fluoropolymers with polymers with good mechanical properties, e.g. with polyethylene terephthalate (hereinafter also called "PET").
• PET polyethylene terephthalate
• fluoropolymers are often incompatible with other polymers and generally do not mix.
• a two-phase mixture is often formed in which the fluoropolymers form spatial islands.
• the proportion by weight of fluoropolymer that can be metered in is therefore often limited, since the boundary layers of the polymers adhere to one another only poorly. In fibers, this property manifests itself as a "tendency to splice".
• Fibers made of synthetic polymers and fabrics made from them have the disadvantage, however, that they can become charged with static electricity.
• Conductive fibers for the production of textile fabrics, such as fabrics for technical use, or for other purposes, e.g. for brushes have always been the target of numerous developments.
• a flame retardant, electrically conductive fabric which contains electrically conductive and flame-retardant electrically non-conductive fibers.
• the electrically conductive fibers can contain electrically conductive particles such as carbon black or metal particles, have metal coatings or consist of electrically conductive materials such as polyanilines. Polyester and polyolefins are described as fiber materials.
• DE-A-39 38 414 describes high-strength fabrics made of synthetic fibers, which are woven in the form of electrically conductive fibers in warp and weft, and still contain electrically non-conductive fibers.
• the electrically conductive fibers consist of polyolefins and contain graphite or carbon black.
• EP-A-160,320 describes core-sheath monofilaments for use in hair brushes made from selected polymers.
• the core contains nylon or polyester which comprise at least 60% by weight of polybutylene terephthalate units.
• the jacket contains special nylon types or copolyether esters.
• DE-U-86/06334 discloses core sheath fibers, the core of which consists of thermoplastic, preferably polyamide, and the sheath of which is made of electrically conductive plastic, preferably of polyamide, which contains carbon black or metals.
• JP-A-07 / 278,956 describes electrically conductive copolyesters which mainly contain polybutylene terephthalate units and which are doped with carbon black. Core-sheath fibers made from this material are also described, in which the core consists of aromatic polyester.
• electrically conductive heterofilaments are known, which can be configured, for example, as core-sheath fibers.
• PET and other polyesters or PET / nylon are described as examples of core and sheath polymers.
• WO-A-01 / 20,076 discloses nonwovens with a high dielectric constant. Mixtures of polyvinylidene fluoride and polypropylene are proposed as fiber material. The products made from it are characterized by an extended half-life of electrostatic charges and can be used as electrostatic filters.
• US-A-6,085,061 describes a brush for cleaning electrostatically charged surfaces.
• Core-sheath fibers whose core is electrically conductive and whose sheath is made of polyvinylidene fluoride can be used as fiber materials.
• DE-A-44 12 396 discloses melt-spun undrawn, electrically non-conductive fibers with a core-sheath structure, the sheath of which contain fluoropolymers.
• Polycarbonate is used as the core polymer.
• This fiber is used as an optical fiber and is due to its low strength for technical textiles such as technical fabrics, not suitable.
• high reflection at the boundary layer and the lowest possible attenuation of the electromagnetic wave are important. Both properties can only be achieved by using a high-purity coating.
• JP-A-2001-127,218 describes a semiconducting fiber made of a fluoropolymer containing carbon black. This fiber has no core-sheath structure and is used for the production of non-wovens, for example by the melt-blow process. The fiber is not drawn.
• the present invention was based on the object of combining the application-related advantages of the materials known for fiber production without having to accept the disadvantages known from the use of the individual materials.
• adhesion problems normally occur at the interface between two polymers. This applies in particular when using fluoropolymers known to have poor adhesion with other polymers. Surprisingly, it has been shown that very good adhesion to the polymer core can be achieved when using a fluoropolymer doped with electrically conductive particles.
• Another object of the present invention is therefore to provide core-sheath fibers with good adhesion between the individual layers.
• the present invention thus provides fibers, in particular monofilaments, which combine high chemical and antistatic properties thermal resistance and good mechanical dimensional stability and high tensile strength.
• the invention relates to a melt-spun fiber with a core-sheath structure and a tensile strength of at least 15 cN / tex, the core of which contains a synthetic thermoplastic polymer that is not a fluoropolymer, and the sheath of which contains at least one melt-spinnable fluoropolymer and particles of electrically conductive material.
• the synthetic thermoplastic polymers forming the core can be of any nature as long as they are melt-spinnable and give the fiber the properties desired for the particular application. Fluoropolymers are not included in the synthetic thermoplastic polymers, although in addition to these polymers the core may also contain fluoropolymers as a blend component.
• thermoplastic materials are polyolefins, such as polyethylene, polypropylene or copolymers containing ethylene and / or propylene units in combination with other alpha-olefin units copolymerized therewith, such as alpha-butylene, alpha-pentylene, alpha-hexylene or alpha-octylene; Polyesters such as polycarbonate, aliphatic / aromatic polyesters or fully aromatic polyesters; Polyamides, such as aliphatic or alphatic / aromatic polyamides (nylon types) or fully aromatic polyamides (aramids); or polyether ketones, that is to say polymers which have at least ether and ketone groups and generally aromatic divalent radicals, such as phenylene, in the repeating chain, many combinations of these groups being possible, for example PEK, PEEK or PEKK; or polyarylene sulfides, preferably polyphenylene sulfide; or polyether esters, that is to say polymers which have at least
• the core of the core-sheath fibers according to the invention preferably contains polyamides and in particular polyester.
• thermoplastic polyamides which are preferably used in the compositions according to the invention are known per se.
• thread-forming polyamides such as aliphatic or aliphatic / aromatic polyamides, such as e.g. Polycaprolactam, poly- (hexamethylene-1,6-diaminadipic acid diamide), poly- (hexamethylene-1,6-diamine-sebacic acid diamide), poly- (hexamethylene-1,6-diamine-terephthalic acid diamide) or poly- (hexamethylene -1,6-diamine isopthalklarediamid); or also completely aromatic polyamides, such as poly (phenylene-1,4-diamine-terephthalic acid diamide) or poly- (phenylene-1,4-diamine-isophthalic acid diamide).
• aliphatic or aliphatic / aromatic polyamides such as e.g. Polycaprolactam, poly- (hexamethylene-1,6-diaminadipic acid diamide), poly- (hexamethylene-1,6-diamine-sebacic
• the polyamides used according to the invention usually have viscosity numbers according to DIN 53727 of 120 to 350, preferably 150 to 320 cm 3 / g (measured at 25 ° C. in sulfuric acid).
• thermoplastic polyesters and / or aromatic liquid-crystalline polyesters used with particular preference in the compositions according to the invention are known per se.
• thread-forming polyesters such as polycarbonate or aliphatic / aromatic polyesters, such as, for example, polybutylene terephthalate, polycyclohexanedimethyl terephthalate, polyethylene naphthalate or in particular polyethylene terephthalate, but also completely aromatic, liquid-crystalline polyesters, such as polyoxibenzonaphtoate.
• Modules of thread-forming polyesters are preferably diols and dicarboxylic acids or correspondingly constructed oxycarboxylic acids.
• the main acid component of the polyesters is terephthalic acid or cyclohexanedicarboxylic acid, but other aromatic and / or aliphatic or cycloaliphatic dicarboxylic acids may also be suitable, preferably para or trans-aromatic compounds, such as 2,6-naphthalene dicarboxylic acid or 4,4'-biphenyldicarboxylic acid , but also p-hydroxy-benzoic acid.
• aliphatic Dicarboxylic acids such as adipic acid or sebacic acid, are preferably used in combination with aromatic dicarboxylic acids.
• Typical suitable dihydric alcohols are aliphatic and / or cycloaliphatic and / or aromatic diols, for example ethylene glycol, propanediol, 1,4-butanediol, 1,4-cyclohexanedimethanol but also hydroquinone.
• thermoplastic polyesters are selected in particular from the group consisting of polyethylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polypropylene terephthalate, polybutylene terephthalate, polycyclohexanedimethanol terephthalate, polycarbonate or a copolycondensate containing polybutylene glycol, terephthalic acid and naphthalene acid and naphthalene units.
• thermoplastic polyesters are aromatic, liquid-crystalline polyesters, in particular polyesters containing p-hydroxybenzoate units.
• polyesters which are to be used in hot and humid environments, such as monofilaments when used in paper machines and which contain polyester as the core component
• these polyesters are preferably stabilized against hydrolytic degradation by adding polyester stabilizers.
• Such stabilized fibers show a significant reduction in the degradation tendency of the polyester, so that lifetimes of monofilaments can be achieved, which are equivalent to those of monofilaments based on extremely resistant fiber materials, such as polyarylene sulfides or oxides.
• Fibers containing polyester stabilized in the core are particularly preferred, particularly preferably carbodiimides.
• the polyesters used according to the invention usually have solution viscosities (IV values) of at least 0.60 dl / g, preferably from 0.60 to 1.05 dl / g, particularly preferably from 0.62-0.93 dl / g ( measured at 25 ° C in dichloroacetic acid (DCE)).
• IV values solution viscosities
• the fluoropolymers forming the jacket can also be of any nature as long as they are melt-spinnable.
• the fluoropolymers used according to the invention are poly (fluoroolefin) homopolymers and / or copolymers derived from ethylenically unsaturated fluorine-containing olefin monomers and other monomers copolymerizable therewith. Such polymers are also known per se.
• melt-spinnable copolymers of tetrafluoroethylene with other alpha-olefins such as ethylene, propylene, butylene, hexylene or octylene.
• Homopolymers or copolymers can also be used which are derived from other fluorine-containing monomers, for example from mono-, di- or trifluoroethylene, from vinyl fluoride or in particular from vinylidene fluoride.
• melt-spinnable copolymers of tetrafluoroethylene with at least one alpha-olefin, preferably with ethylene is particularly preferred.
• PVDF Polyvinylidene fluoride
• the invention therefore also relates to a heterofilament fiber containing at least two components, the first component being an electrical insulator and one thermoplastic polymer that is not a fluoropolymer and the second component comprises polyvinylidene fluoride.
• the particles of electrically conductive material present in the sheath of the melt-spun fiber according to the invention can be of any nature as long as they give the sheath an increased electrical conductivity.
• These can be particles of carbon, for example carbon fibers, carbon black or graphite; from metals, for example from copper, silver, aluminum or iron; made of metal alloys, for example bronze; or act from conductive plastics, for example from polyanilines or from polypyrrole.
• the particles can be in any form, for example in the form of fibers or in the form of round or irregular particles.
• the content of the electrically conductive particles in the jacket should be selected so that there is a significant increase in the electrical conductivity of the plastic material. Typical amounts are in the range of up to 50% by weight, preferably 2 to 15% by weight, based on the amount of the jacket material.
• Melt-spun fibers in which the sheath contains between 2% by weight and 15% by weight, in particular between 4% by weight and 9% by weight, of electrically conductive particles are particularly preferred.
• the core-sheath fibers according to the invention can be in any form, for example as multifilaments, as staple fibers or in particular as monofilaments.
• the titer of the core-sheath fibers according to the invention can also vary within wide ranges. Examples of this are 100 to 45,000 dtex, in particular 400 to 7,000 dtex.
• Monofilaments are particularly preferred.
• Monofilaments whose cross-sectional shape is round, oval or n-angular are particularly preferred, n greater than or equal to 3.
• the staple lengths for staple fibers can also vary widely, for example between 30 and 70 mm.
• the core of the core-sheath fiber according to the invention forms the mechanical carrier of the fiber, while the sheath mainly determines the usage properties, such as antistatic behavior and sliding behavior.
• a commercially available PET raw material can preferably be used as the core.
• a fluoropolymer based on PVDF is particularly preferably used for the jacket, which was previously processed into a spinnable mixture, in particular with carbon black.
• the proportion by weight of component A) forming the core to component B) forming the shell is, based on the total amount of these components, 50 to 95% by weight, preferably 60 to 80% by weight, for component A) and 50 to 80% by weight for component B) 5% by weight, preferably 40 to 20% by weight.
• the core-shell fibers according to the invention can be produced by methods known per se.
• the two polymers or mixtures containing these polymers are preferably dried immediately before being fed into the extruder, melted in the extruder and filtered through a spin pack.
• the fluoropolymer is provided with the electrically conductive particles. This is usually done before the fluoropolymer is fed to the extruder, but can also be done immediately before the spin pack. Masterbatches containing the fluoropolymer and electrically conductive particles can also be used.
• the molten polymer thread is cooled in a spinning bath, for example a water bath, and then wound up or drawn off.
• the pulling-off speed is greater than the spraying speed of the polymer melt and thus causes the thread formed to stretch.
• the heterofilament spun thread thus produced is then preferably subjected to post-drawing, particularly preferably in several stages, in particular a two- or three-stage post-drawing, with a total drawing ratio of 1: 3 to 1: 8, preferably 1: 4 to 1: 6.
• heat setting preferably follows, using temperatures of 130 to 280 ° C; work is carried out at a constant length or a shrinkage of up to 30% is permitted.
• the spinning take-off speed is usually 10-40 m per minute.
• thermoplastic polymer of the core and the fluoropolymer of the shell are spun into a bicomponent monofilament in a core-shell structure, surprisingly a very good core-shell adhesion is shown.
• the conductivity of the jacket can be lost during stretching, but can be restored by heat treatment and the shrinkage caused thereby, preferably above the melting point of the jacket material, but below the melting temperature of the core.
• the surface properties are mainly determined by the conductively doped fluoropolymer.
• the fibers according to the invention are distinguished by very good dirt repellency, good chemical resistance and electrical conductivity.
• the combination with the fluoropolymer leads to fibers with improved sliding properties compared to fibers made of pure thermoplastic polymer. These fibers show increased dirt repellency compared to fibers made from pure thermoplastic polymer.
• the fibers according to the invention can contain auxiliaries.
• auxiliaries are processing aids, stabilizers, antioxidants, plasticizers, lubricants, pigments, matting agents, viscosity modifiers or crystallization accelerators.
• processing aids are siloxanes, waxes or longer-chain carboxylic acids or their salts, aliphatic, aromatic esters or ethers.
• stabilizers and antioxidants are the polyester stabilizers already mentioned above, phosphorus compounds, such as phosphoric acid esters or carbodiimides.
• pigments or matting agents examples include organic dye pigments or titanium dioxide.
• viscosity modifiers are polyvalent carboxylic acids and their esters or polyvalent alcohols.
• the fibers according to the invention are preferably used for the production of textile fabrics, such as woven fabrics, knitted fabrics, knitted fabrics, laid fabrics and nonwovens.
• Textile fabrics containing monofilaments according to the invention are particularly suitable for technical purposes, such as for filters, as screen printing materials or in particular as paper machine screens.
• the monofilaments according to the invention have good textile-physical properties and are easy to weave.
• the fabrics have the usual dimensional stability of the core-forming thermoplastic polymers.
• Fabrics made from these monofilaments are ideally suited for technical fabrics, particularly in the filtration of aggressive media, where there is also a risk of electrostatic charging; i.e. especially in solid-gaseous and solid-liquid filtration.
• the invention also relates to the use of the fibers for the production of textile fabrics which are used in environments with high chemical and / or physical stress, in particular as paper machine screens or as technical fabrics, such as those e.g. in filtration, for the production of conveyor belts or as reinforcing inserts.
• the fibers are used as monofilaments and in particular as weft threads in the fabric.
• the use of the monofilaments according to the invention as paper machine screens can be in the forming section, the press section or in particular in the dryer section respectively. In the dryer section, the monofilaments according to the invention are used in particular as spiral screens.
• the fibers used according to the invention in particular in the form of monofilaments, usually have a titer range from 10 to 4500 tex, an elastic modulus from 2.0 to 8.0 N / tex, a tenacity-related strength from 15 to 50 cN / tex Elongation at break from 15 to 45% and a hot air shrinkage at 180 ° C from 1.0 to 20.0%.
• Core-shell fibers made of polyethylene terephthalate and polyvinylidene fluoride containing carbon black
• PET polyethylene terephthalate
• PVDF polyvinylidene fluoride
• the core-sheath monofilament obtained had the following properties: titres 2890 dtex strength 24 cN / tex HLS (hot air shrink 10 'at 160 ° C) 2.5% loop strength > 20 cN / tex elongation 44% BZD (reference elongation at 12 cN / tex) 8.5% BZD (reference elongation at 15 cN / tex) 13% EGG. Resistance (10 mm clamping length) 8 * 10 5 (ohms) EGG. Resistance (150 mm clamping length) 9 * 10 6 (ohms)

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Textile Engineering (AREA)
• Manufacturing & Machinery (AREA)
• Multicomponent Fibers (AREA)
• Chemical Or Physical Treatment Of Fibers (AREA)
• Treatments For Attaching Organic Compounds To Fibrous Goods (AREA)
• Laminated Bodies (AREA)

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Publications (3)

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• 2002
  • 2002-10-24 DE DE10249585A patent/DE10249585B4/de not_active Expired - Fee Related
• 2003
  • 2003-09-18 DE DE50311164T patent/DE50311164D1/de not_active Expired - Lifetime
  • 2003-09-18 EP EP03021088A patent/EP1413653B1/fr not_active Expired - Lifetime
  • 2003-09-18 AT AT03021088T patent/ATE422570T1/de active
  • 2003-09-18 DK DK03021088T patent/DK1413653T3/da active
  • 2003-09-18 PT PT03021088T patent/PT1413653E/pt unknown
  • 2003-09-18 ES ES03021088T patent/ES2321389T3/es not_active Expired - Lifetime
  • 2003-10-07 US US10/680,284 patent/US20040078903A1/en not_active Abandoned
  • 2003-10-22 PL PL03363021A patent/PL363021A1/xx not_active Application Discontinuation
  • 2003-10-24 JP JP2003364329A patent/JP2004143659A/ja active Pending

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