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
  • 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
  • D01F6/92—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 polyesters
• • 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 filaments having very high electrical conductivities and excellent mechanical properties.
• These threads in particular in the form of monofilaments, can be used, for example, in screens or in conveyor belts.
• polyester fibers for technical applications are in most cases subjected to high mechanical and / or thermal stresses during use.
• the material must have good dimensional stability and constancy of force-elongation properties over as long as possible usage periods.
• the material must not be electrostatically charged during processing and during use.
• polyester-based manmade fibers have proven successful in such environments, when used in humid-hot environments, polyesters are prone to mechanical abrasion in addition to hydrolytic degradation.
• abrasion can have a variety of causes.
• the sheet forming screen or forming fabric is pulled in paper machines for dewatering suction boxes with the result of increased Siebverschl constituentes.
• screen wear occurs due to differences in speed between the paper web and the screen surface or between the screen surface and the surface of the drying drums.
• Tissue wear also occurs in other technical fabrics due to abrasion; e.g. in conveyor belts by grinding over fixed surfaces, in filter fabrics by mechanical cleaning and in screen printing fabrics by passing a squeegee over the screen surface.
• Multi-ply fabrics are used in the forming fabrics of modern paper machines.
• vacuum boxes are used on the underside of the sieve to accelerate the dewatering of the paper web by means of negative pressure.
• the contact surfaces of the edges of these suction boxes with the forming fabric are usually made of ceramic to prevent excessive wear on the suction boxes.
• monofilaments of polyamide e.g. made of polyamide 6 or polyamide 6.6. Otherwise, monofilaments of polyethylene terephthalate (hereinafter referred to as "PET"), of which the forming wire essentially consists, are predominantly used because of the higher dimensional stability.
• PET polyethylene terephthalate
• a proven design is the so-called interchangeable shot on the underside of the sieve: Here, an excess of a polyamide monofilament with the following PET monofilaments is used alternately. This achieves a compromise between abrasion resistance and dimensional stability.
• thermoplastic polyurethane TPU
• thermoplastic polyester such as polyethylene terephthalate isophthalate
• thermoplastic polyurethane having melting points of 200 to 230 ° C were used (see, eg EP-A-674.029 ).
• polyester compositions of crystalline thermoplastic polyester resins, polyester elastomers and sorbitan esters are made DE 691 23 510 T2 known. These are characterized by good moldability, in particular by a good release ability.
• polyester compositions containing an aromatic polycarbonate, a polyester derived from alkanediol and benzene dicarboxylic acids, and a polyester urethane elastomer or a polyether imide ester elastomer are known. These have improved flow properties while maintaining good mechanical properties.
• a finished thread is coated with a mixture of nano-carbon tubes and a polymer. Since the coated thread is not stretched further, the carbon bridges of the amorphous coating are not ruptured, resulting in very good electrical conductivities.
• the object of the present invention is to provide filaments which have excellent electrical conductivity, good mechanical properties and excellent abrasion resistance.
• filaments generally refers to fibers of finite length (staple fibers), fibers of infinite length (filaments) and multifilaments composed of staple fibers or secondary thereto spun yarns understood.
• the melt-spun threads are preferably used in the form of monofilaments.
• modulus of elasticity is understood to mean the secant modulus of the force-strain characteristic between 0 and 1% elongation.
• elastic elongation is understood as meaning the linear progression of the force-strain characteristic from its origin to the deviation from the linearity.
• An elastic elongation of 0.5% thus corresponds to a linear course of the force-strain curve from 0% to 0.5% elongation; an elastic elongation of 1.5% therefore a linear curve of the force-elongation characteristic of 0% to 1.5%.
• polyester of component a thread-forming polyesters according to the invention are used which, after spinning, stretching and, if appropriate, relaxing, give threads with the moduli of elasticity and elastic strains described above.
• these are polyethylene terephthalate homopolymers or copolymers containing ethylene terephthalate units. These polymers are thus derived from ethylene glycol and optionally further alcohols and terephthalic acid or its polyester-forming derivatives, such as terephthalic acid esters or chlorides.
• thermoplastic polyesters are known per se. Building blocks of thermoplastic copolyesters a) are preferably the abovementioned diols and dicarboxylic acids, or correspondingly constructed polyester-forming derivatives.
• Primary acid component of the polyesters is terephthalic acid, optionally together with minor proportions, preferably up to 15 mol%, based on the total amount of the dicarboxylic acids, of other aromatic and / or aliphatic and / or cycloaliphatic dicarboxylic acids, preferably with para- or trans-aromatic compounds, such as 2,6-naphthalenedicarboxylic acid or 4,4'-biphenyl-carboxylic acid, and preferably with isophthalic acid and / or with aliphatic dicarboxylic acids, such as with adipic acid or sebacic acid.
• suitable dihydric alcohols may be used. Typical representatives thereof are aliphatic and / or cycloaliphatic diols, for example propanediol, 1,4-butanediol, cyclohexanedimethanol or mixtures thereof.
• Examples of preferred components a) are copolyesters which, in addition to polyethylene terephthalate units, have further units derived from alkylene glycols, in particular ethylene glycol, and aliphatic and / or aromatic dicarboxylic acids, such as adipic acid, secacic acid or isophthalic acid.
• Particularly preferred components a) are polyethylene terephthalate homopolymers or copolyesters containing recurring structural units of the polyethylene terephthalate, repeating structural units of the polyethylene adipate, polyethylene sebacate or especially of the polyethylene isophthalate.
• the polyesters of component a) 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 to 0.93 dl / g, (measured at 25 ° C in dichloroacetic acid (DCE)).
• IV values solution viscosities
• Threads of polyesters with a content of free carboxyl groups of less than or equal to 3 meq / kg are preferred.
• These preferably contain a means for occluding free carboxyl groups, for example a carbodiimide and / or an epoxide compound.
• Such treated polyester yarns are stabilized against hydrolytic degradation and are particularly suitable for use in humid-hot environments, especially in paper machines or as a filter.
• thermoplastic and elastomeric block copolymers of component b) can be of very different types. Such block copolymers are known to the person skilled in the art.
• components b) are thermoplastic and elastomeric polyurethanes (TPE-U), thermoplastic and elastomeric polyesters (TPE-E), thermoplastic and elastomeric polyamides (TPE-A), thermoplastic and elastomeric polyolefins (TPE-0) and thermoplastic and elastomeric styrene Block copolymers (TPE-S).
• TPE-U thermoplastic and elastomeric polyurethanes
• TPE-E thermoplastic and elastomeric polyesters
• TPE-A thermoplastic and elastomeric polyamides
• TPE-0 thermoplastic and elastomeric polyolefins
• TPE-S thermoplastic and elastomeric styrene Block copolymers
• thermoplastic and elastomeric block copolymers b) can be composed of a wide variety of monomer combinations. As a rule, these are blocks of so-called hard and soft segments.
• the soft segments are typically derived from polyalkylene glycol ethers in TPE-U, TPE-E and TPE-A.
• the hard segments are typically derived from short chain diols or diamines in TPE-U, TPE-E and TPE-A. In addition to the diols or diamines, the hard and soft segments of aliphatic, cycloaliphatic and / or aromatic dicarboxylic acids or diisocyanates are built up.
• thermoplastic polyolefins are block copolymers comprising blocks of ethylene-propylene-butadiene and of polypropylene (EPDM / PP) or of nitrile-butadiene and of polypropylene (NBR / PP).
• Particularly preferred components b) are thermoplastic and elastomeric styrene block copolymers.
• block copolymers which have blocks of styrene-ethylene and of propylene-styrene (SEPS) or of styrene-ethylene and of butadiene-styrene (SEBS) or of styrene and of butadiene (SBS).
• thermoplastic block copolymer and elastomeric block copolymer are block copolymers which behave at room temperature comparable to the conventional elastomers, but can be plastically deformed under heat supply and thus exhibit a thermoplastic behavior.
• thermoplastic and elastomeric block copolymers have in some areas physical crosslinking points (e.g., minor valence forces or crystallites) that dissolve on heat without the polymer molecules decomposing.
• carbon black and / or graphite particles are used. These are carbon blacks or graphites whose primary particles are arranged in the form of aggregates, which preferably have the shape of a tang, in particular having the shape of elongated filaments.
• the carbon blacks used according to the invention consist of nanoscale primary particles. These are generally spherical and typically have diameters in the range from 10 to 300 nm. Due to the strong anisotropy of the aggregates of carbon black particles or graphite platelets used according to the invention, longitudinally aligned aggregates form during the spinning of the thread, which are electrically conductive along the longitudinal axis of the thread Form paths. In the unstretched thread these aggregates are partially present in a näulter form and are stretched by stretching in the thread longitudinal direction, but not torn. In this way, the electrically conductive paths are obtained in the thread.
• Particularly preferably used components c) are carbon blacks, which are present in the form of elongate aggregates made up of a plurality of primary particles in contact with one another and the drawn thread has an electrical conductivity of at least 0.5 ⁇ 10 -6 Siemens / cm, preferably at least 1 , 0 * 10 -5 Siemens / cm, measured in the longitudinal direction of the thread.
• the amounts of components a), b) and c) in the threads according to the invention can be selected within wide limits.
• the threads typically contain from 20 to 70% by weight of component a), from 15 to 40% by weight of component b) and from 5 to 50% by weight of component c), in each case based on the total mass of the thread.
• the combination of components a), b) and c) used according to the invention gives the filaments not only excellent abrasion resistance, but also good textile-technological properties, in particular good dynamic properties and excellent dimensional stability, as well as excellent electrical conductivity.
• the components a), b) and c) required for producing the threads according to the invention are known per se, some are commercially available or can be prepared by processes known per se.
• the threads according to the invention may contain, in addition to components a), b) and c), further auxiliaries d).
• processing aids 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.
• antioxidants are phosphorus compounds, such as phosphoric acid esters or sterically hindered phenols.
• pigments or matting agents examples include organic dye pigments or titanium dioxide.
• viscosity modifiers are polybasic carboxylic acids and their esters or polyhydric alcohols.
• the threads according to the invention can be in any desired form, for example as multifilaments, as staple fibers, as secondary spun yarns, also in the form of twisted yarns, or in particular as monofilaments.
• the threads according to the invention are present as multicomponent threads.
• these are side-on threads or, in particular, core-sheath threads.
• the sheath preferably consists of a composition comprising components a), b), c) and optionally d) and the core consists of a filament-forming polymer which determines the mechanical properties, mainly the strength and elongation at break, of the total filament.
• a particularly preferred combination is a core-sheath thread whose core consists of polyester, preferably of polyethylene terephthalate, and whose sheath contains the components a), b), c) and optionally d).
• the weight ratio of core to sheath is 95: 5 to 20:80, preferably 75:25 to 45:55, more preferably 70:30 to 50:50.
• the titer of the threads according to the invention can vary within wide limits. Examples are 1 to 45,000 dtex, in particular 100 to 4,000 dtex.
• the cross-sectional shape of the threads according to the invention may be arbitrary, for example round, oval or n-cornered, where n is greater than or equal to 3.
• the threads of the invention can be prepared by methods known per se.
• composition comprising components a), b), c) and optionally d) is preferably used in the form of a masterbatch.
• the threads according to the invention are drawn one or more times during production.
• a polyester produced by solid phase condensation is used.
• the hot polymer filament is cooled, e.g. in a cooling bath, preferably in a water bath, and then wound up or peeled off.
• the removal speed is greater than the injection rate of the polymer melt.
• the yarn produced in this way is then re-stretched one or more times, optionally fixed and wound up, as is known from the prior art for the abovementioned melt-spinnable polymers.
• the threads according to the invention are preferably used for the production of textile surface constructions, in particular of woven fabrics, spiral fabrics, laid or knitted fabrics. These textile surface constructions are preferably used in screens.
• Textile surface constructions containing the threads according to the invention are likewise the subject of this invention.
• the threads according to the invention can be used in all industrial fields. They are preferably used in applications in which increased wear and static electricity due to mechanical stress are to be expected. Examples thereof are the use in screen fabrics and filter cloths for gas and liquid filters, in dry belts, for example for the production of food, in packaging containers or in hoses for conveying small particles. These uses are also the subject of the present invention.
• filaments of the invention in the form of monofilaments relates to their use as conveyor belts or as components of conveyor belts.
• the threads according to the invention can also be used in screens intended for use in paper machines.
• PET polyethylene terephthalate
• the melted spun masses from both extruders were spun, drawn and drawn into a bicomponent 20-hole spinneret with a hole diameter of 1.0 mm at a flow rate of 488 g / min and a take-off speed of 31 m / min into core-shell monofilaments heat-set in the hot-air duct at 255 ° C under heat-shrinkage.
• the textile technological data of the monofilaments obtained are shown in Table 1.
• the PET used was a type with an IV value of 0.72 dl / g.
• the masterbatch consisted of 50% by weight of the PET type described above, and 27% by weight of a thermoplastic elastomeric styrene block copolymer, 20% by weight of a conductivity carbon black and 3% by weight of processing stabilizer, lubricant, steric hindered amine and silane.
• a commercially available antistatic monofilament (Homer AIX from the Albany Group) served as comparison.
• Example 1 1) Example 2 1) Comparative example tensile strenght 20.8 20.4 13.6 (CN / tex) Modulus of elasticity (GPa) 11.8 10.6 11.8 elastic 1.3 1.4 1.3 Strain (%) Elongation at break (%) 32.5 60.6 31.3 Titre (dtex) 2715 2703 4483 el. resistance 1.6 * 10 -5 1.8 * 10 -5 6.6 * 10 -6 (S / cm) 1) The products of Examples 1 and 2 differed in heat setting

Landscapes

• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Textile Engineering (AREA)
• Manufacturing & Machinery (AREA)
• Artificial Filaments (AREA)
• Woven Fabrics (AREA)
• Multicomponent Fibers (AREA)
• Filtering Materials (AREA)
• Belt Conveyors (AREA)

Applications Claiming Priority (1)

Publications (3)

Family

ID=39531295

Family Applications (1)

Country Status (6)

Cited By (3)

Families Citing this family (13)

Citations (7)

Family Cites Families (11)

• 2007
  • 2007-02-24 DE DE102007009119A patent/DE102007009119A1/de not_active Withdrawn
• 2008
  • 2008-01-25 PT PT08001372T patent/PT1961846E/pt unknown
  • 2008-01-25 AT AT08001372T patent/ATE540145T1/de active
  • 2008-01-25 EP EP08001372A patent/EP1961846B1/fr active Active
  • 2008-02-14 JP JP2008032962A patent/JP2008231654A/ja active Pending
  • 2008-02-21 US US12/070,782 patent/US20080207799A1/en not_active Abandoned
  • 2008-02-21 US US12/070,818 patent/US7825174B2/en active Active

Patent Citations (7)

Also Published As

Similar Documents

Legal Events