DE4321289A1 - Electret fibres with improved charge stability, manufacture thereof, and textile material containing same - Google Patents

Abstract

Published without abstract.

Description

The present invention relates to electret fibers due to a level of charge control agents significantly improved Have charge stability, their production and thread and sheet-like textile materials, in particular yarns, cables and Nonwovens consisting of these improved electret fibers or these contain.

Electret fibers in the context of this invention are fibers electrically non-conductive materials that have an applied able to store electrostatic charge for a long time.

Electret fibers are so far mainly related to the Problem of ultrafine dust filtration has been described. (Eg from Biermann, "Evaluation of permanently charged elektrofibrous 17. DOE Nuclear Air Cleaning Conference, Denver, USA, (1982) and in man-made fibers / textile industry 40/92, (1990/9)). The filter materials described differ both regarding the materials that make up the fibers also in terms of the way in which the electrostatic charge is applied to the fibers.

The electrostatic charge can be generated by various methods be applied.

So it is possible to use polymer films on both sides to charge different electrostatically and then to split. This gives so-called split-film fibers, which in the Usually be stored as a fiber fleece.

Furthermore, it is known to be in a strong electrostatic field to spin in or the spun fibers or Fiber products, e.g. B. fleeces, an electrical  Corona discharge, z. B. between high-tensioned tips or Wires and grounded surface electrodes, suspend.

Particularly advantageous is the charging by triboelectric Effects, d. H. Charge separation by friction of the fiber materials with other media, eg. B. other polymer materials, solids such as metal surfaces or liquid or gaseous media.

Various fiber raw materials have been investigated and recommended to electret fibers with advantageous Electret properties, such as long-lasting charge stability, To produce moisture and chemical resistance. there should these advantageous properties even if possible low cost.

Here are fluoropolymers such as polytetrafluoroethylene or Perfluorinated ethylene / propylene copolymers as very good Electrified materials, the high charge stability, characterized by a charge half-life (charge Life span) from years to decades, with good Combine temperature stability and low moisture absorption. Serious disadvantages of these polymers, such as their high price and the great difficulties of their processing, however, have theirs Use largely prevented.

Good resistance to chemicals and moisture also have Electret fibers of polyolefins, such as polyethylene and Polypropylene, or polycarbonates. commercial Fine filter consist of these electret materials (Chemical fibers / textile industry, as indicated above). One serious disadvantage of these fibers is the relatively low Charge half-life only on the order of about one Year lies. This is usually a too short period of time one considers that z. B. when using the fibers for the Filtering the time from fiber manufacturing to Use of the filter plus the filter life easily can be over a year.

As long as electret fibers for the production of  It was therefore recommended to use and use particulate filters constant urgent need to find a fiber material, the value for money with significantly improved charge stability, Resistance to moisture and chemicals, as well as good textile and mechanical properties combined and there are already known proposals for this.

U.S. Patent 4,789,504 recommends that Effectiveness of polypropylene electret filters thereby increase in that a fatty acid salt is added to the polymer material becomes.

It is from Journal of Electrostatics, 24 (1990) pp. 283-293 known that the temperature at which under standardized Measuring conditions on the charge density of a polyacrylate electret half sinks, rising from 126 to 180 ° C, when the polymer is about 10 wt .-% titanium dioxide is added. However, this addition has in addition to a deterioration of mechanical properties a increased moisture sensitivity resulting in a use in filter materials.

It has now been found that it is possible to produce fibers, the excellent textile properties and a considerable extended half-life of the electric charge, d. H. a have significantly improved charge stability.

The electret fibers according to the invention with improved Charge stability are characterized in that they consist of a Material consist, the predominantly a thread-forming Polymer or polycondensate and 0.01 to 30% by weight (preferably 0.01 to 10, in particular 0.1 to 5 wt .-%), based on the weight of the material, organic or contains organometallic charge control agent.

Fibers in the context of the present invention are continuous fibers (Filaments) or staple fibers, preferably with staple lengths of 0.5 to 50 mm or pulp, split fibers or split-film fibers, the also in special embodiments for special Applications may be present.  

Low or partially oriented electret fibers, d. H. such only little or no stretched, like normal fibers as a hotmelt adhesive fiber for solidification of z. B. fleeces be used; High-shrinkage electret fibers can be used for Compaction and solidification of textile fabrics, be used in particular by nonwovens.

Multicomponent electret fibers may be in core / sheath arrangement or in side-by-side arrangement, one of the Components is the electret fiber according to the invention.

Multi-component fibers and their preparation are described for. B. in "Falkai, synthetic fibers", page 124 ff. in particular Fig. 5.4. Multi-component fibers with an inventive Electret components can be used for special purposes z. B. side by side fibers as self-crimping fibers when the Components have a different heat shrinkage; Core / sheath fibers as adhesive fibers when the sheath is a relative has low melting point, or at appropriate Cross-sectional arrangement of the components, eg. In the Iceland / Sea Arrangement, also as split fibers for the production of particularly fine Titre of the electret fibers.

Another interesting core / sheath arrangement of the Fibers of the invention consist of a core of normal Polymer material and a jacket made of electret material.

Preference is given to fibers according to the invention with particularly large Surface, d. H. fine titers z. B. below 3 dtex, in particular below 2 dtex, or multilobal profile fibers z. B. polygonal or star-shaped profiles or for example ribbon or Dumbbell profiles.

The fibers can be used in all processing conditions, such. B. as Monofilaments, as a debris or flake, as a pulp slurry, as linear structures such as spun yarn, multifilament yarn, cables, Sliver, or as a fabric such as Wirrvliese from stack or Endlosfasern in particular Spunbonds or carding or Kardenvliese, scrim, fabric or knitwear available.

The electret fibers according to the invention are particularly preferred in  Shape of multifilament yarns, cables and nonwovens.

Subject of this invention are both the electrically neutral Fibers and fiber products, such. Yarn, cable or nonwoven fabrics, as well as the electrostatically charged. It is irrelevant whether the charge was deliberately applied (eg by Corona discharge) or spontaneously due to triboelectric effects originated.

While the improved electrical properties of the Electret fibers according to the invention substantially on the characteristic electret behavior of its manufacture Based on the material used, the result application advantages in their entirety from the advantageous combination of electrical and mechanical, and form-related properties.

The material of which the fibers according to the invention are made is characterized by the fact that he

• a) after an electrical charge, a maximum of Discharge current at a temperature above 50 ° C, preferably between 100-250 ° C, in particular between 100 and 180 ° C. wherein the Entladestromkurve after passing through the Maximums again has a pronounced sloping branch, and
• b) at 25 ° C a half-life of the electric charge of has at least 6 months, where
• c) its charge halving temperature above 100 ° C, preferably between 100-250 ° C, in particular between 100 and 180 ° C and
• d) after a standard charging (unilaterally grounded film of 50 .mu.m thickness, exposed for 3 min. Corona discharge) has a charge density of at least 1 x 10 ^-9 Coulomb / cm².

The improvement in charge stability naturally correlates with certain limits with the concentration of the charge control agent in the material of the electret fibers according to the invention.  

The concentration is adjusted so that the fibers face conventional a sufficient improvement in electrical Properties while maintaining good textile technology and mechanical properties.

The electret fibers according to the invention surprisingly show a high triboelectric effect, d. H. they are strong to do so spontaneously by interacting with their environment charge. This causes z. B. one of these fibers Existing or these fibers containing dust filter without Separate electrical charging (eg by a corona Discharge) when flowing with gases (eg in use) or by friction on other types of solid materials spontaneously a much higher electrostatic charge and thus a much better particle separation achieved than an equal constructed dust filter made of normal fibers.

The measurement of the discharge current of the material takes place in the Way that a circular, clamped in a holder sample a film made of the material on one side with a Aluminum layer is vaporized, with the metallized side on a grounded metal block is placed and of the free one Page is charged with a corona discharge for 3 min. After that The sample is cooled and left for a few hours at normal temperature conditioned. Subsequently, the discharge of the electret sample using the "Air Gap Current TSC" method (described in "Electrets", editor G.M.Sessler, in "Topics in Applied Physics", 2nd edition, (1987), Vol. 33, p. 95 ff., Springer Verlag) a heating rate of 2 ° C / min measured.

During heating, the discharge current is continuously measured and recorded against the temperature.

Characteristic of the material, in addition to the amount of charge, the location of the temperature peaks of the discharge and the Presence of a sloping branch of the discharge curve behind the Peaks.

The half-life of the electric charge is the period of time  within that originally on the electricty material applied charge at 25 ° C has dropped to half.

Below the charge halving temperature is that temperature be understood, in the charge density of the material half of its value at 25 ° C falls.

The improved electrical properties result from the Composition of the material.

The material usually consists mostly of one Polymer or polycondensate, but other polymers or Contain monomers or inorganic additives, the usually in synthetic fiber materials for training special properties are present. As an example, only called the matting agents.

As polymers in the context of this invention are not only the high molecular weight compounds obtained by polymerization, such as As polyolefins, polyacrylates, polyacrylonitrile u. like. but also the polycondensation producible, such as As polyester or polyamides, etc.

The polymers and polycondensates which are used in the process according to the invention material to be used are predominantly included in the Usually intrinsic viscosities from 0.45 to 1.2, preferably 0.6 to 0.9 dl / g, measured in dichloroacetic acid at 25 ° C.

The thread-forming polymer or polycondensate of The material to be used according to the invention is melt-spinnable or solution spinnable.

From solutions by wet or dry spinning process spinnable Polymers allow the use of thermally less stable Charge control agents.

An embodiment of the invention is characterized that the material predominantly a thread-forming polymer Contains from the group of polyolefins, halogenated Polyolefins, polyacrylates, polyacrylonitrile, polystyrene and Fluoropolymers.  

Preferably, such a material contains predominantly one filament-forming polymer from the group polyethylene, Polypropylene, polyacrylonitrile, polytetrafluoroethylene and perfluorinated ethylene / propylene copolymer, in particular from Group polyethylene and polypropylene.

Another embodiment of the invention is characterized characterized in that the material predominantly a thread-forming Polycondensate contains from the group of polyesters, in particular Polyalkylene terephthalate, such as. For example, polyethylene terephthalate, Polycarbonates, aliphatic or aromatic polyamides, Polyimides, polyether ketones (eg PEK and PEEK), polyarylene sulfides in particular polyphenylene sulfide, polyacetals and cellulose esters, especially cellulose 2 1/2 and tri-acetate.

Electret fibers of aromatic polyamides according to the invention, Polyether ketones (eg, PEK and PEEK), and polyarylene sulfides in particular polyphenylene sulfides meet in particular Demands for increased chemical and / or thermal Resistance.

Another preferred embodiment of the invention is characterized characterized in that the material predominantly a thread-forming Polycondensate from the group of polyesters, polyether ketones and Contains polyphenylene sulfide, in particular polyalkylene terephthalate. Another preferred embodiment of the invention is characterized in that the material predominantly Contains polypropylene.

Polypropylene and polyester electret threads according to the invention may, from the point of view of varietal purity (slight Recyclability) with particular advantage in the automotive industry be used.

The material of the electret fibers according to the invention contains a Charge control agents, as in toners for electrophotographic Processes is included.

Charge control agents for electrophotographic processes are in  large number known from the patent literature.

Accordingly, the material contains as charge control agent one or more compounds from the following classes:
triphenylmethane; Ammonium and immonium compounds; fluorinated ammonium and immonium compounds; biscationic acid amides; polymeric ammonium compounds; diallylammonium compounds; Aryl sulfides derivatives; Phenol derivatives; Phosphonium compounds and fluorinated phosphonium compounds; Calix (n) arenes; Metal complex compounds; benzoimidazolones; or azines, thiazines or oxazines, which are listed in the Color Index as Pigments, Solvent Dyes, Basic Dyes or Acid Dyes.

Charge control agents used individually or in combination with each other are contained in the electret fibers according to the invention and the Fibers convey very good electret properties:

• 1. Triarylmethane derivatives such as, for example:
  Color Index Pigment Blue 1, 1: 2, 2, 3, 8, 9, 9: 1, 10, 10: 1, 11, 12, 14, 18, 19, 24, 53, 56, 57, 58, 59, 61, 62, 67 or, for example, Color Index Solvent Blue 2, 3, 4, 5, 6, 23, 43, 54, 66, 71, 72, 81, 124, 125 and those in the Color Index under Acid Blue and Basic Dye listed triarylmethane compounds, provided that they are suitable in terms of their temperature stability and processability, such as Color Index Basic Blue 1, 2, 5, 7, 8, 11, 15, 18, 20, 23, 26, 36, 55, 56, 77th , 81, 83, 88, 89, Color Index Basic Green 1, 3, 4, 9, 10, which in turn are particularly suitable for Color Index Solvent Blue 125, 66 and 124.
• Particularly suitable is Color Index Solvent Blue 124 in the form its highly crystalline sulfate or trichloro-triphenylmeth tetrachloraluminats.
• Further examples for the preparation according to the invention Electret fibers are well suited charge control agents of Triphenylmethane series are the in DE-PS 19 19 724 and DE PS 16 44 619 described compounds.  
• Furthermore, triphenylmethanes as described in US-A-5 051 585, in particular those of the formula 1 wherein
  R¹ and R³ are the same or different and -NH₂, a mono- and dialkylamino group whose alkyl groups have 1-4, preferably 1 or 2, C atoms, a mono- or di-omega hydroxyalkylamino group whose alkyl groups have 2-4, preferably 2C- Have atoms, an optionally N-alkyl-substituted phenyl or phenalkylamino whose alkyl has 1-4, preferably 1 or 2 C atoms whose phenalkyl group in the aliphatic bridge has 1 to 4, preferably 1 or 2 C atoms and their phenyl nucleus one or two of the following substituents: alkyl having 1 or 2 C atoms, alkoxy having 1 or 2 C atoms and can carry the sulfonic acid group, mean
  R² is hydrogen or has one of the meanings given for R¹ and R³,
  R⁴ is hydrogen, halogen, preferably chlorine, or a sulfonic acid group or together with R⁵ forms a fused phenyl ring,
  R⁵ together with R⁴ forms a fused-on phenyl ring,
  R⁶, R⁷, R⁹ and R¹⁰ are each hydrogen or an alkyl radical having 1 or 2 C atoms, preferably methyl, and
  R⁸ is hydrogen or halogen, preferably chlorine, and
  X ^{- represents} one equivalent of an anion, in particular a chloride, sulfate, molybdate, phosphomolybdate and borate anion. Particularly preferred is a charge control agent of formula 1 wherein R¹ and R³ phenylamino groups R² is an m-methylphenylamino group and the radicals R⁴ to R10 are all hydrogen.
• Second Ammonium and immonium compounds as described in US-A-5,015 676th
• 3. fluorinated ammonium and immonium compounds as described in US Pat. No. 5,069,994, especially those of the formula 3 wherein
  R¹ perfluorinated alkyl having 5-11 C atoms,
  R², R³ and R⁴ are the same or different and are alkyl having 1 to 5, preferably 1 to 2 C atoms,
  X ^{- is} one equivalent of an anion, preferably a tetrafluoroborate or tetra-phenylborate anion.
• Preferably means
  R¹ perfluorinated alkyl having 5-11 C atoms,
  R² and R³ are ethyl and
  R⁴ methyl
• 4. Bis-cationic acid amides as described in PCT-A-91/10172, especially those of the formula 4 wherein
  R¹, R² and R³ are identical or different alkyl radicals having 1-5 C atoms, preferably methyl,
  n is an integer from 2 to 5,
  and X ^{- represents} one equivalent of an anion, preferably a tetraphenylborate anion.
• 5. Diallylammonium compounds as described in DE-A-41 42 541, in particular those of the formula 5 wherein
  R¹ and R² denote identical or different alkyl groups having 1-5, preferably 1 or 2, C atoms, but in particular stand for methyl groups and X ^{- represents} one equivalent of an anion, preferably represents a tetraphenylborate anion, as well as those from these obtainable polymeric ammonium compounds of formula 6 (as described in DE-A-40 29 652 or DE-A-41 03 610), wherein n has a value corresponding to molecular weights of 5,000 to 500,000. However, particular preference is given to compounds of the formula 6 having molecular weights of 40,000 to 400,000.
• 6. Arylsulfide derivatives as described in DE-A-40 31 705, in particular those of the formula 7 wherein
  R¹, R², R³ and R⁴ denote identical or different alkyl groups having 1-5, preferably 2 or 3, C atoms, and
  R⁵ is one of the divalent radicals -S-, -SS-, -SO- or -SO₂-.
  For example, R¹ to R⁴ are propyl groups and R⁵ is the group -S- S-.
• 7. phenol derivatives as described in EP-A-0 258 651, in particular those of the formula 8 wherein
  R¹ and R³ are alkyl or alkenyl groups having 1 to 5, preferably 1 to 3, C atoms and R² and R⁴ are hydrogen or alkyl having 1 to 3, preferably methyl.
• As an example may be mentioned the compounds in which R¹ to R⁴ Methyl groups or in which R² and R⁴ are hydrogen and R¹ and R³ stand for the group -CH₂-CH = CH₂.
• 8. Phosphonium compounds and fluorinated phosphonium compounds as described in US Pat. No. 5,021,473 and in US Pat. No. 5,147,748, in particular those of the formula 9 wherein
  R¹, R², R³ and R⁴ denote identical or different alkyl groups having 1-8, preferably 3 to 6, C atoms, and X ^{- represents} one equivalent of an anion, preferably a halide anion
  and 10; wherein
  R¹ is a highly fluorinated alkyl radical having 5-15, preferably 6-10, C atoms,
  R², R³ and R⁴ are alkyl having 3-10 C atoms or phenyl and
  X ^{- stands} for one equivalent of an anion.
• As an example of a compound of formula 9 is called tetrabutyl phosphonium bromide, as examples of compounds of formula 10 may be mentioned the compounds with R¹ = C₈F₁₇-CH₂-CH₂-, R² = R³ = R⁴ = phenyl and X ^- = PF₆- or the tetraphenylborate anion.
• 9. Calix (n) arene as described in EP-A-0 385 580 and as described in EP-A-0 516 434, in particular those of the formula II wherein
  R is hydrogen, halogen, preferably chlorine, straight-chain or branched alkyl having 1-12 C atoms, aralkyl, z. B. benzyl or phenethyl, -NO₂, -NH₂, -NHR¹ or HR¹R², where R¹ is alkyl having 1-8 C-atoms, optionally substituted phenyl or -Si (CH₃) ₃.
• 10. Metal complex compounds, such as chromium, cobalt, iron, zinc or aluminum azo complexes or chromium, cobalt, iron, zinc or aluminum salicylic acid complexes of the formulas 12, 13 and 14 wherein
  M is a 2- or 3-valent metal atom, preferably chromium, cobalt, iron, zinc or aluminum,
  Y and Z are divalent aromatic rings, preferably the formulas m is one of the numbers 1 or 2 and K⁺ is one equivalent of a cation, wherein
  M is a 2- or 3-valent metal atom, preferably chromium, cobalt, iron,
  R¹ is hydrogen, halogen, preferably Cl, nitro or amidosulfonyl
  R² is hydrogen or nitro,
  R³ is hydrogen, the sulfonic acid group, -CO-NH-R⁴, where R⁴ = phenyl, alkyl having 1-5 C atoms, which may be substituted by a mono-, di- or trialkylamino group if necessary, and
  Z is a counterion which establishes the neutrality of the complex, preferably a proton, an alkali or an ammonium ion, wherein
  M is a divalent metal central atom, preferably a zinc atom,
  R¹ and R² are identical or different, straight-chain or branched alkyl groups having 1-8, preferably 3-6 C atoms, for example tert. Butyl, mean.
• Such compounds are described in EP-A-0 162 632, US-A-4 908,225, EP-A-0 393 479, EP-A-0 360 617, EP-A-0 291 930, EP-A-0 280,272, EP-A-0 255 925, EP-A-0 251 326, EP-A-0 180 655, EP-A-0 No. 141,377, US Pat. No. 4,939,061, US Pat. No. 4,623,606, US Pat. No. 4,590,141 and / or US Pat characterized by the CAS numbers 31714-55-3, 104815-18-1, 84179-68-8, 110941-75-8, 32517-36-5, 38833-00-00, 95692-86-7, 85414-43-3, 136709-14-3, 135534-82-6, 135534-81-5, 127800-82-2, 114803-10-0, 114803-08-6.
• Examples of particularly preferred metal complex compounds of formula 13 above are given in the following table.

  table

• 11. Benzimidazolones as described in EP-A-0 347 695, in particular those of the formula 15 wherein
  R¹ is alkyl having 1-5 C atoms and R² is alkyl having 1-12 C atoms
  and X ^{- is} one equivalent of an anion, especially a chloride or tetrafluoroborate anion.
• As an example may be mentioned the compound with R¹ = CH₃ and R² = C₁₁H₂₃
  or Azines of the following Color Index numbers: CI Solvent Black 5, 5: 1, 5: 2, 7, 31 and 50; CI Pigment Black 1, CI Basic Red 2 and CI Basic Black 1 and 2.

The material preferably contains as charge control agent one or more different compounds from the following classes:
Triphenylmethanes of the formula 1; Diallylammonium compounds of the formula 5 and the polymeric ammonium compounds of the formula 6 obtainable therefrom; Aryl sulfide derivatives of the formula 7; Metal complex compounds of the formulas 12 and 13.

Particular preference is given to electret fibers according to the invention whose material contains as charge control agent a compound of the formula 1 in which R¹ and R³ are phenylamino and R² is 3-methylphenylamino and X ^{- is} a sulfate equivalent. This compound, known as CI Solvent Blue 124, corresponds to the following Formula 16:

Particular preference is also given to electret fibers according to the invention whose material contains as charge control agent a compound of formula 5 or 6, wherein R¹ and R² is methyl and X ^{- is} a tetraphenylborate anion.

Furthermore, particular preference is given to the invention Electret fibers whose material as a charge control agent a A compound of formula 7 wherein R¹, R², R³ and R⁴ are propyl and R⁵ is a Disulfide bridge, or the formula 13, wherein R¹ is chlorine, R² Hydrogen and Z is a proton contains.

The versatile applications of the invention Electret fibers are made possible by the combination of the above described material composition with the by in the Forming conditions applied to adjust textile technical data of the fibers. It is surprising that the electret fibers come with virtually the same bandwidth textile properties, like the fibers consisting of the corresponding polymer without charge control agent Addition were made.

The electret fibers according to the invention have a titer in the range from 0.02 to 20 dtex.

In the case of "split-film fibers" comes an average Titers of 0.02 to 30 dtex, with small proportions coarser and finer fibers.

Fibers with a titer of 0.02 to 1 dtex, in particular of 0.02 to 0.5 dtex preferably by the "splitting" technique (not confused with the split-film technique). there are bicomponent fibers that are made of electrolytic material and a in a solvent-soluble material with "Iceland in the Sea "- cross sections are produced and where the Electrolyte forms the islands, with the relevant Solvent treated. This dissolves the soluble components bicomponent fiber and it will be extraordinary preserved fine island fibers.

The electret fibers according to the invention are further characterized in that the tensile strength of the fibers is 20 to 80, preferably 30 to 65 cN / tex,
the elongation at break 10 to 200%, preferably 10 to 60%, in particular 20 to 50%,
the heat shrinkage, measured at 200 ° C dry (S₂₀₀) 0 to 50%, preferably <10%
is.

Tear strength, elongation and heat shrinkage are controlled in a customary manner during production by adjusting the spinning speed, the stretching and the fixing conditions as required.
Tensile strengths of 20-30 cN / tex are interesting for special applications, where it is important that the fibers can break under certain loads. The usual textile application range requires strengths of about 30-60 cN / tex. On the other hand, technical fiber materials must have high strengths in the range up to about 80 cN / tex.
Elongation is also set according to the application. For technical, high-strength yarns low strains of about 10-15% are required, normal textile applications are adjusted to fiber materials with an elongation of about 20-40%, for special applications, eg. As for the production of three-dimensionally deformable textile fabrics, yarns with the highest possible extensibility, for example up to 200%, are desirable.
The shrinkage of the fiber materials is set for conventional textile applications to values below 10%, for the production of staple fiber webs z. B. to <5%. However, it can also pronounced high shrinkage fibers for special applications, eg. B. for densification or crimping of fabrics may be of interest.

The electret fibers according to the invention can have a Preparation application from 0 to 0.3 wt .-%, preferably 0 to 0.15 % By weight. A preferred embodiment prepared Electret fibers according to the invention is that they have a have hydrophobic preparation, in particular one that as hydrophobizing agent wax or a fluoropolymer such. B.  Polytetrafluoroethylene, contains.

As already indicated above, the inventive Electret fibers in various forms as linear or planar formations exist. In particular, they can be in shape multifilament yarns, cables and nonwovens.

The multifilament yarns according to the invention have as planned Use usually titres of 20 to 500 dtex and 10 to 200 Capillaries and have substantially the above textile technical values of the electret fibers according to the invention. Of course, the yarns can also be used as blended yarns other synthetic as well as natural fibers wherein the non-electret fibers are not only with respect to their electrical properties, but also in terms of their usual textile properties, such as tear strength, elongation at break, Shrinkage behavior, etc. of the electret fiber according to the invention can distinguish.

This is especially important when special effects, such as B. high bulk effects, loop yarn effects, core-shell Structures u. Like. Should be produced, or if the yarns Melt fibers should contain so that they are in a Stiffen the heating.

Cables are multifilament strands with a few thousand to some Million individual capillaries, with the selection within this Scope with regard to the planned end use.

In the form of cables, the electret fibers according to the invention the further processing and processing levels, eg. B. the crimping, the Drawing, fixation, dyeing equipment, etc. be supplied.

Also, the electret fibers according to the invention in the form of Cables are easily stored.

The nonwovens of the electret fibers according to the invention provide a particularly valuable form of these fibers  single described below. Your main application area lies in the production of fine dust filters.

The electret fibers according to the invention can of course also in combination with a non-electret material as Two-component fibers are present.

They can, for example, as a bicomponent fiber with Core / shell structure with a core of electret material of the Claim 1 specified composition and a coat lower melting polymer material.

Such fibers can with particular advantage for the production of continuous or staple fiber webs bonded by heating be used.

The electret fibers according to the invention can also be used as Bicomponent fiber with core / sheath structure made up of a core Normal fiber material, d. H. any spinnable Polymer material, and a jacket of electrified material of the above present composition.

The electret fibers according to the invention can also be used with others Fiber materials, eg. B. with effect yarns or melt fibers be processed together into nonwovens or blended yarns, z. B. Commingel yarn spun or blown.

The present invention also relates to a method for Production of the electret fibers according to the invention by spinning a thread-forming material from the melt or from a Solution in a suitable solvent, wherein in per se known Way after the wet spinning or dry spinning process can be worked, if necessary cooling the spun filaments, peeling at a speed in the Range of about 100 to 8000 m / min, preferably from 1000 to 5000 m / min and subsequent further, usual Procedural steps, such as drafting and depending after the intended further use Wirrablage, Summary of yarns or cables, texturing, fixation,  Cut to staple fibers, which is characterized in that a Material is spun, the predominantly a thread-forming Polymer or polycondensate and 0.01 to 30% by weight (preferably 0.01 to 10, in particular 0.1 to 5 wt .-%), based on the weight of the material, organic or contains organometallic charge control agent.

Alternatively, the invention also relates to a method for Production of the electret fibers according to the invention by splitting of fissile multilobal fibers extending along the fiber axis containing extending segments of the electret material or by matrix resolution of an "Island in the Sea" filament of Island areas consist of the electrictive material, or by Splitting a foil from the electrified material, which also characterized in that the electret material predominantly a filament-forming polymer or polycondensate and 0.01 to 30 wt .-% (preferably 0.01 to 10, in particular 0.1 to 5 wt. %), based on the weight of the material, organic or contains organometallic charge control agent.

As further alternatives for the production of the invention Electret fibers take into account the fiber blowing process, such as it is described in German Patent Application 19 64 060 or "flash" spinning in the electrostatic field, as in U.S. Patent 3,319,309, each of which is incorporated herein by reference Use of the electret material to be used according to the invention.

In melt spinning, the electret material on a Temperature of about 30-50 ° C above the melting point of the polymer heated and the melt in the usual way through spinnerets extruded. The temperature of the melt is within the specified range chosen so that an optimal flow of the Material sets the not too high spinning pressure for the orientation of the filaments required shear forces allowed to build.

For example, a material that is predominantly made Polypropylene is, at about 260 ° C, a material based on  Polyester spun at about 280-310 ° C.

If the polymer spun from the melt, so must the filaments withdrawn through the spinning openings by cooling be solidified. The cooling can be done in any known way be executed and also allows in the processing of Elektreterkstoffs the targeted control of Filament. So z. B. a delay of cooling possible by a Rechauffeur if fibers with a special Shrinkage / strength characteristic to be produced or it can be a sharp asymmetric blowing done when Self-crimping fibers are to be produced. Especially recommended for the production of fine single titers under 1 dtex In contrast, a so-called. Central blowing, the one particular uniform and thus tension-free cooling of the filaments guaranteed.

The spinning of the electret fibers according to the invention from solutions the material in a suitable solvent also takes place according to well-known methods. In principle, the same conditions as normal polymers. The Solidification of the emerging from the spinneret solution, during Dry spinning, by evaporation of the solvent or, in Wet spinning, by precipitation of the material in filament form in a Fällbad done.

This results in advantages in particular in terms of Material composition. It can then also such Materials are used, which are a charge control agent contained, which at the melting temperature of the polymer material is not stable.

In the spinning processes mentioned can except spinnerets with round spinning openings and those used with profile openings and it can by special arrangements known per se or - Designs of the openings Mehrkomponentenfilamente in Side by side arrangement or core-sheath type spun become.

Deducting speeds down to 100 m / min  mainly used for the production of titers above 4 dtex. Economically more interesting spin spinning speeds between 1000 and 5000 m / min, in particular very fine titers spun at the highest speeds of this range become.

The production of the material to be spun according to the invention happens by homogeneous incorporation of the charge control agent in the polymer material from which the material predominantly consists. It is particularly advantageous, the charge control agent in Form of a masterbatch.

The spun filaments are usually stretched the extent of which, on the one hand, depends on the spin orientation the filaments, on the other hand of the desired strength and Extensibility properties is determined. While filaments the were obtained at spinning speeds below 1000 m / min need vigorous stretching, if they are too textile yarns or Fabrics are to be processed, the extent of the required stretching with increasing spinning speed steadily, since these filaments already a relatively high Have spinning orientation.

Feinsttiter, at the highest speeds of this Sphere are spun, therefore, fully oriented Filaments (so. FOY) and require no Nachverstreckung.

If high-strength filaments are to be produced, then one is Drawing up to an elongation at break of about 10% and below usual, for particularly stretchy filaments, z. For manufacturing of thermoformable fabrics, the stretching is only low and is calculated so that elongation at break of up to 200% yield.

The filaments can be stretched either in the form of Multifilamentgarnen or in the form of cables are subjected.

The tension required for drawing can by Godets or by drawing dies or stretching shafts  be generated. While godets through the filaments or yarns Dragging friction on the rotating godet surface are in Stretching or stretching the filaments through a entrained strong air flow.

A special meaning comes with the stretch shafts at the Wirrablage of filament material for the production of random webs, especially of "spunbonds" too.

The stretching can be at room temperature or at elevated Temperature, in particular above the glass transition point be executed. A so-called cold stretching usually leads to special high shrink filaments, the hot stretch leads to filaments, the usual textile technically expedient Have shrinkage values of 0 to 10%.

The stretching of the filament materials can be done in a known manner one or more stages.

The electret fibers according to the invention can also be used with all be provided known texturing. So it is possible the Filaments, preferably in cable form, one Subjecting stuffer box crimping; they can be present finer fiber bundle by swirling nozzles with or without Overfeeding of a portion of the supplied fibers to more or less closed yarns or too fancy yarns or too to be swirled to snare yarns or they can False-twist texturing or stretched False-wire texturing be subjected.

Further textile technical embodiments of the multifilament yarns arise when the electret fibers according to the invention in Combination with fibers of different shrinkage Bicomponent yarns are spun in which the triggering shrinking leads to a spontaneous ripple.

Also the side-by-side mentioned above Bicomponent fibers with an electret share can be chosen a component with one of the electret material different shrinkage characteristics by triggering the Shrinking be curled.  

A particularly preferred form for the invention Electret fibers, as already said above, the form of Fleeces.

Namely, these nonwovens can with particular advantage for Production of highly effective and particularly durable dust filters, in particular of fine dust filters, are used.

Surprisingly, it has been found that it is possible, high textile properties, especially stability and a very variable construction with a very considerable Extension of the half-life of the electric charge to combine when the fibrous material of the nonwoven fabric contains or consists of electret fibers according to the invention.

An object of the present invention is thus a Nonwoven fabric consisting of or containing synthetic fibers, wherein this nonwoven fabric at least in part from inventive Electret fibers is constructed.

The proportion of electret fibers in the nonwoven, the this the desired property combination mediates, u. U. be surprisingly small.

Often there is a noticeable economic and technical Advantage already for a nonwoven which is at least 10% Contains electret fibers.

In general, it is expedient to use a nonwoven fabric, the 50-100% contains electret fibers, with the highest technical Requirement profiles are naturally fulfilled with nonwovens can consist of 100% electret fibers.

The titers of the synthetic fibers of the invention in Nonwovens and any products made from them, in particular the dust filter, are in the for these applications usual range.

From case to case it may be useful to use mixed titers In particular, in such nonwovens, not 100  % of electret fibers, electret fibers and normal fibers have different titers.

The synthetic fibers can be continuous fibers or staple fibers, suitably with staple lengths of 0.2-200 mm, be. In this case, nonwovens of continuous fibers are preferably in the form of Spunbonds ago, staple fibers with staple lengths less than 20 mm conveniently by Naßlegeverfahren, staple fibers with Staple lengths over 20 mm expediently by carding too Nonwovens processed.

However, it is also readily possible nonwovens which contain both continuous and staple fibers. So can be z. B. in many cases the desired Property combination of a filament nonwoven fabric (such consists of continuous filaments) by mixing in a suitable Adjust the proportion of electret staple fibers.

Furthermore, it may be useful to produce nonwovens Mixtures of two or more varieties of the invention Electret fibers, each variety being another of the above Contains charge control agent.

Of course, mixtures of electret Staple fibers and normal staple fibers to a spunbonded nonwoven fabric be stored in confusion.

This tray can, as usual, by dry or wet Take place. The drying of the staple fibers takes place in usually on the card, the filing of continuous fibers after the Spunbond process immediately after spinning. It can the spun filaments go through a stretched shaft, in which they are stretched and one for the filing on the running sieve advantageous speed be accelerated. A consolidation of the Spunbonds is usually done by a Calender passage of the freshly deposited filament mass.

The suitable synthetic fibers generally consist of the spinnable polymers specified above, in particular from Polyamide, polyacrylonitrile, polyethylene, polypropylene or  Polyester.

Preference is given to synthetic fibers of polyester, in particular of Polyethylene terephthalate, and polypropylene.

The solidification of the nonwovens can in principle in each done known manner. So it is possible, for example, that Nonwoven through a binder to solidify with the fleece is impregnated and then cured or the Binder may be a melt binder, the z. B. in powder form or is incorporated in the web in the form of binder yarns, and the the nonwoven solidified by heat to the nonwoven fabric.

The solidification of the nonwoven fabric to nonwoven fabric can also by Calendering done, with some mechanical entanglement the filaments, partly an autogenous weld to the Crossing points occurs.

Of course, the hot-melt adhesive material may also be used as a Component of a side-by-side bicomponent fiber or as Cloak of a core-sheath bicomponent fiber into the nonwoven be introduced.

Advantageously, nonwovens according to the invention have proved, which has been mechanically solidified. Under one mechanical consolidation is for example the needles too understand or z. B. hydromechanical solidification, as they z. As described in EP-A-0 108 621.

A combination of different types of consolidation can after Need also done.

The weight per unit area of the nonwovens according to the invention depends of course, after the scheduled deployment. Usually it is 5 to 300 g / m², preferably at 100 to 250 g / m², but can for special tasks also about z. B. at up to 1000 g / m².

Further preferred embodiments of the invention Nonwovens are a spunbond, in particular by needling or Hot-melt adhesive consolidated spunbond or even a dry or wet-laid solidified by hot melt adhesive Staple fiber nonwoven fabric.  

Optionally, the nonwoven fabric with another Textile material z. B. another nonwoven or a Textile material defined yarn layer, which also made Electret fibers or may contain such combined become.

In particular, occasionally the combination with supportive and reinforcing or protective covering textile materials he wishes. In a preferred embodiment, the or non-woven webs according to the invention especially on both sides with a protective textile material, z. B. a nonwoven fabric, in particular a fine fleece covered. In particular when using the nonwovens according to the invention as Dust filter is often the combination with coarse or deep filters appropriate.

The present invention also relates to a method for Production of the Nonwovens According to the Invention by Wirrablage of synthetic continuous or staple fibers in per se known Weise (cf .: "Radko Krcema, Handbuch der Textilverbundstoffe", Deutscher Fachverlag GmbH (1970), page 53) on a moving Underlay, or by fleece formation from staple fibers on the Card or card, then solidification, that by is characterized in that at least a part of the stored Synthetic fibers are electret fibers.

In the production of spunbond nonwovens, the According to the invention contain a proportion of electret fibers can a mixture of electret fibers and normal staple fibers in the desired mixing ratio in a conventional manner filed dry or after a Naßlegeverfahren to fleece and subsequently solidified.

But it is also possible, nonwovens made of endless fibers and To produce staple fibers by the filing of the Endlosfasern an admixture of the staple fibers provides. In In this case, either the continuous fibers or the Staple fibers wholly or partly made of electret fibers.  

Also in the production of nonwovens after the spunbond process It is possible to use normal fibers and electret fibers when filing to mix. For this example, the electret fibers be prepared separately and from fiber reservoirs, for. B. Coil racks, peeled off and through tuyeres in the on the Tray directed fiber stream of normal fibers fed be, or the spinning beams, which are used to produce the Fleece filaments serve, in addition to spin openings for Normal fibers also have spinning openings for electret fibers, the ratio of the different spinning apertures and the Amount of filaments spun from the desired filaments Ratio of normal and electret fibers in the nonwoven fabric equivalent.

In general, for the production of nonwoven fabrics according to the invention at least 10% by weight of electret fibers deposited or one Fiber mixture containing at least 10 wt .-% of electret fibers processed on the card or card to fleece.

The proportion of deposited electret fibers is preferably 50 to 100%, and to achieve the maximum effects are 75 to 100 % of the deposited fibers electret fibers.

The solidification of the web to nonwoven fabric takes place in itself known manner using a binder, or a Melt binder or by calendering or, preferably, on mechanical way. However, it is also possible to have different ones combine this solidification process.

Binder can z. B. polymer solutions or dispersions or To be latices that are impregnated or impregnated on the fleece Spray applied and after evaporation of the liquid phase at the crossing points of the filaments Training "binding sails".

But it can also be used Duroplastbinder which, if necessary in a heat treatment, cure and the fiber crossing points fix. Also melt binder, the z. B. in the form of powders or  preferably incorporated in the form of binder fibers the fleece and when heating the web above its melting point converge at the fiber crossing points and binding points form, which after cooling again, the fleece to the nonwoven fabric solidify, can be used with good success.

A similar consolidation can be achieved by the "autogenous" Welding the fleece filaments at their crossing points when you achieve the calf of a calendering close to the fleece Subjecting melting temperature of nonwoven filaments.

Good results also results in a mechanical consolidation z. B. by needling or by hydromechanical hardening, as they are For example, in EP-A-0 108 621 is described. in this connection does not suffer any chemical or thermal stress on the Filament, so that the advantageous physical Properties of the filaments due to their preparation, for. B. be taught by quick-spinning and stretching operations, undiminished transferred to the nonwoven fabric.

For producing a combination of an inventive Nonwoven fabric with a textile material defined yarn layer is the Nonwoven fabric with this textile material to connect so that no Delamination may occur. This requirement is best fulfill, if the connection of the components by needles, Gluing or sewing takes place.

Particularly preferred is the preparation of such composites by firing collar technique.

This is a Kettwirktechnik, in which the Nonwoven directionally oriented through yarns, preferably high solid yarns with or without electret fiber content or off Electret fibers, reinforced. This warp knitting technique will open so-called Raschel machines performed. A special suitable Raschel machine for producing an inventive formed composite material is the type RS 3 MSU-V of the company Karl Mayer, Textilmaschinenfabrik GmbH, Obertshausen.  

The nonwovens, which from the electret fibers according to the invention exist or contain an effective proportion of such - As already mentioned above - with particular advantage to Production of fine filters used.

An object of the present invention is therefore also these Application of the electret fibers and their containing Textile materials, in particular nonwovens.

For manufacturing reasons, it may be advantageous to Fibers before web formation with an antistatic preparation to provide that only at the end of the manufacturing process, for. B. after the finishing of the filters, is washed out.

It has surprisingly been found that in many Cases in the production of nonwovens as an antistatic one unusually diluted preparation or even just water can be used. This embodiment of the Manufacturing process is particularly environmentally friendly.

Then the filters are then targeted, z. B. in one Corona discharge, electrostatically charged.

Moreover, it has surprisingly been found that in the Production of nonwovens from the electret fibers according to the invention on the clutter or in their use as a filter due to the Flow through with gases through triboelectric effects in the In most cases already sufficient electrical charge the nonwovens, so that a separate charging step can be omitted.

The following embodiment illustrates a possible preferred embodiment of the present invention.

example 1

Polyethylene terephthalate fiber raw material was invented modified by mixing with as much of the charge director of formula 16 (C.I. Solvent Blue 124) in the form of a Masterbatches that the concentration of Solvent Blue 124 in the Spunware was 0.5% by weight. It was the masterbatch from the produced highly crystalline form of the charge control agent whose  X-ray diagram (Cu-Kα radiation) contributes a strong reflex 2 δ ° = 18.47, three medium reflections at 2 δ ° = 6.97; 12.1 and 13.9 and weak broad reflections at 2 δ ° = 20.0; 21.7; 22.5; 24.8; 28.2; 30.7 and 32.2.

The material thus produced was after conventional Melt spinning technology spun. The spinning temperature was 285 ° C, the spinning take-off speed was 1500 m / min.

The produced spun goods became also conventional Bandstraßenentechnologie (stuffer box crimping, fixation and Section) to wool-like, modified according to the invention Staple fibers processed with a single titer of 1.3 dtex.

From the manufactured modified staple fibers and from Mixtures of these fibers with normal fibers (titers of normal fibers likewise 1.3 dtex) and in each case 20% by weight of binder fibers (type: Bi-component fiber polyester / co-polyester in core / shell construction with a jacket melting point of 110 ° C, titer 3 dtex) in the below compositions were on a Test card made of nonwovens. Varying was the Basis weight (m) of the nonwovens and the proportion of normal fibers. The nonwoven bonding was carried out thermally at 160 ° C and a Residence time of 3 minutes.

The separation efficiency of the produced nonwovens were in one conventional filter test bench, which works according to the principle of Scattered light measurement works, tested.

The following test parameters were set:
Flow velocity: 20 cm / s, whereby in each case the pressure difference DD stated below,
Particle mass concentration: 50 mg / m³,
Dusting time: varies from 1 to 3 minutes,
Test dust: "ac fine" with the following composition:

particle size Particle content [%] 0.3-0.5 μm 55.5 0.5-1.0 μm 17.3 1.0-3.0 μm 26.6 3.0-5.0 μm 0.5 <5.0 μm Not relevant

Pattern 1:
m = 200 g / m²;
DD = 23 Pa;
80% by weight of fibers modified according to the invention;
20% by weight bicomponent binder fibers

Pattern 2:
m = 200 g / m²
DD = 26 Pa;
40% by weight of fibers modified according to the invention;
40% by weight of normal fibers
20% by weight bicomponent binder fibers

Pattern 3:
m = 200 g / m²;
DD = 25 Pa;
80% by weight of normal fibers
20% by weight bicomponent binder fibers

Pattern 4:
m = 100 g / m²;
DD = 10 Pa;
80% by weight of fibers modified according to the invention;
20% by weight bicomponent binder fibers

Pattern 5:
m = 100 g / m²;
DD = 10 Pa;
80% by weight of normal fibers
20% by weight bicomponent binder fibers.

The separation performances achieved with these nonwoven patterns are The following tables show:

Table 1

Degrees of separation of samples 1 to 5 after a dusting time of 1 minute

Table 2

Degrees of separation of samples 1 to 3 after a dusting time of 2 minutes

Table 3

Degrees of separation of samples 1 to 3 after a dusting time of 3 minutes

Example 2

As in example 1, polyethylene terephthalate fiber raw material was used modified according to the invention with the charge control agent of Formula 16 (C.I. Solvent Blue 124). The mixture was as in Example 1, but here used as much of the masterbatch was that the concentration of the Solvent Blue 124 in the Spunbond 1.0 wt%. Here was again in the Example 1 used, highly crystalline form of Charge control agent used.

Analogously to Example 1, the material thus obtained was spun, in which case a titer of 1.7 dtex was produced. From the fiber material, as described in Example 1, a nonwoven having a basis weight of 200 g / m ² and a binder fiber content of 20 wt .-% (bicomponent fiber as in Example 1) was prepared and solidified.

The nonwoven thus obtained is referred to as pattern 6 below. For comparison was under quite the same spinning and Nonwoven web forming conditions Nonwoven with Solvent Blue 124 modified polyethylene terephthalate produced. This fleece is referred to as pattern 7 in the following.

The separation performance of these two nonwoven patterns are described in the Table 4 below.  

Table 4

Degree of separation T (x) of the nonwoven pattern 6 (according to the invention) and 7 (comparison) after a dusting time of 1 to 10 minutes

Table 4 shows particularly clearly the significant Improvement of the separation performance for fine dusts after a longer time Pollination time, by the use of the invention Nonwoven material is achieved.

Table 5 below shows that the invention Nonwoven material surprisingly after a discharge by a water treatment its very good separation efficiency maintains without an external charge must be made.  

Table 5

Degree of separation T (x) of the nonwoven pattern 6 after immersion in water and subsequent drying

Example 3

Is used instead of the charge control agent of formula 16 used in Example 1 is one of formula 6, wherein R¹ and R² are methyl groups, and X ^{- is} a tetraphenylborate anion whose average molecular weight, determined by measuring the solution viscosity, about 300 000 and that has a melting point / decomposition point of 225 ° C, and otherwise worked exactly as described in Example 1, one arrives at a filter material, which also has very good separation efficiency. The charge control agent of the formula 6 used in this example can be prepared as described in Preparation Example 3 of DE-A-41 03 610. Table 6 below shows the degree of separation T (x) of the nonwoven fabric filter obtained with this charge control agent of the present invention.

Table 6

Separation degrees T (x) of the nonwoven fabric filter obtained with the charge control agent of the formula 6 after dusting times of 1 to 10 minutes

Claims (31)

1. electret fibers having improved charge stability, characterized in that they consist of a material which is predominantly a filament-forming polymer or polycondensate and 0.01 to 30 wt .-% (preferably 0.01 to 10, in particular 0.1 to 5 wt. %), based on the weight of the material, contains organic or organometallic charge control agent. 2. electret fibers according to claim 1, characterized that the thread-forming polymer or polycondensate is melt-spinnable. 3. electret fibers according to claim 1, characterized that the thread-forming polymer or polycondensate solution is spinnable. 4. electret fibers according to any one of claims 1 to 3, characterized in that the material predominantly a thread-forming polymer contains from the group of Polyolefins, the halogenated polyolefins, the Polyacrylates, polyacrylonitrile, polystyrene and Fluoropolymers. 5. electret fibers according to any one of claims 1 to 4, characterized in that the material predominantly a filament-forming polymer contains from the group Polyethylene, polypropylene, polyacrylonitrile, Polytetrafluoroethylene and perfluorinated ethylene / propylene Copolymer. 6. electret fibers according to claim 5, characterized that the material predominantly a thread-forming Polymer contains from the group polyethylene and Polypropylene.   7. Elektretfasern according to any one of claims 1 to 3, characterized in that the material predominantly a thread-forming polycondensate contains from the group of Polyester, polycarbonates, aliphatic or aromatic Polyamides, polyimides, polyether ketones (eg PEK and PEEK), Polyarylene sulfides, in particular polyphenylene sulfide, Polyacetals and cellulose esters. 8. Elektretfasern according to any one of claims 1 to 3 and 7, characterized in that the material predominantly contains a filament-forming polycondensate the group of polyesters, polyether ketones and Polyphenylene sulfide. 9. electret fibers according to claim 8, characterized that the material predominantly polyalkylene terephthalate contains. 10. electret fibers according to any one of claims 1 to 9, characterized in that the material predominantly Contains polypropylene. 11. electret fibers according to any one of claims 1 to 10, characterized in that the material a Charge control agent contains as in toners for Electrophotographic processes is included. 12. electret fibers according to any one of claims 1 to 11, characterized in that the material contains as charge control agent one or more compounds from the following classes:
triphenylmethane; Ammonium and immonium compounds; fluorinated ammonium and immonium compounds; biscationic acid amides; polymeric ammonium compounds; diallylammonium compounds; Aryl sulfides derivatives; Phenol derivatives; Phosphonium compounds and fluorinated phosphonium compounds; Calix (n) arenes; Metal complex compounds; benzoimidazolones; or azines, thiazines or oxazines, which are listed in the Color Index as Pigment Dyes, Solvent Dyes, Basic Dyes or Acid Dyes. 13. Electret fibers according to at least one of claims 1 to 12, characterized in that the material contains as charge control agent one or more different compounds from the following classes:
Triphenylmethanes of the formula 1; Ammonium and immonium compounds of the formula 2; fluorinated ammonium and immonium compounds of the formula 3; biscationic acid amides of formula 4; Diallylammonium compounds of the formula 5; the obtainable from these available polymeric ammonium compounds of formula 6; Aryl sulfide derivatives of the formula 7; Phenol derivatives of the formula 8; Phosphonium compounds and fluorinated phosphonium compounds of formulas 9 and 10; Calix (n) arene of formula 11; Metal complex compounds of formulas 12, 13 and 14; Benzimidazolones of formula 15; or azines of the following Color Index numbers: CI Solvent Black 5, 5: 1, 5: 2, 7, 31 and 50-; CI Pigment Black 1, CI Basic Red 2, CI Basic Black 1 and 2, and CI Oxidation Base 1; or thiazines of the following Color Index numbers: CI Basic Blue 9, 24 or 25 and CI Solvent Blue 8; or oxazines of the Color Index numbers CI Pigment Violet 23, CI Basic Blue 3, 10 or 12; and the azines, thiazines and oxazines listed in the Color Index under Basic Dye or Acid Dye as far as they tolerate the spinning and processing temperatures of the electret material. 14. Electret fibers according to at least one of claims 1 to 13, characterized in that the material contains as charge control agent one or more different compounds from the following classes:
Triphenylmethanes of the formula 1; Diallylammonium compounds of the formula 5 and the polymeric ammonium compounds of the formula 6 obtainable therefrom; Aryl sulfide derivatives of the formula 7; Metal complex compounds of the formulas 12 and 13. 15. Electret fibers according to any one of claims 1 to 14, characterized in that the material contains as charge control agent a compound of formula 1, wherein R¹ and R³ phenylamino and R² is 3-methyl-phenylamino and X ^{- is} a sulfate equivalent. 16. Electret fibers according to any one of claims 1 to 15, characterized in that the material contains as charge control agent a compound of formula 5, wherein R¹ and R² is methyl and X ^{- is} a tetraphenylborate anion. 17. Elektretfasern according to any one of claims 1 to 16, characterized in that the material as Charge control agent contains a compound of formula 7, wherein R¹, R², R³ and R⁴ are propyl and R⁵ is a disulfide bridge is. 18. electret fibers according to any one of claims 1 to 17, characterized in that the material as Charge control agent contains a compound of formula 13, wherein R¹ is chlorine, R² is hydrogen and Z is a proton. 19. Electret fibers according to any one of claims 1 to 18, characterized in that it has a titer in the range from 0.02 to 15 dtex. 20. electret fibers according to any one of claims 1 to 19, characterized in that the tensile strength of the fibers 20 to 80, preferably 30 to 65 cN / tex,
the elongation at break 10 to 200%, preferably 10 to 50%, in particular 20 to 30%,
the heat shrinkage, measured at 200 ° C dry (S₂₀₀), 0 to 50%, preferably <10%. 21. Electret fibers according to any one of claims 1 to 20, characterized in that it has a Preparation application from 0 to 0.3 wt .-%, preferably 0 to 0.08 wt.% Have. 22. Elektretfasern according to any one of claims 1 to 21, characterized in that it takes the form of Multifilament yarns, cables and nonwovens are present. 23. Elektretfasern according to any one of claims 1 to 22, characterized in that in combination with a non-electret material as bicomponent fibers available. 24. Elektretfasern according to any one of claims 1 to 23, characterized in that they are as bicomponent fiber with core / shell structure with a core out Electrolyte specified in claim 1 Composition and a coat of lower present melting polymer material. 25. Elektretfasern according to any one of claims 1 to 24, characterized in that they are as bicomponent fiber with core / shell structure with a core of one any spinnable polymeric material and a sheath of electret material specified in claim 1 Composition present. 26. A process for the preparation of the electret fibers of the claim 1 by spinning a thread-forming material from the Melt or from a solution in a suitable Solvent, wherein in a conventional manner after the Naßspinn- or the dry-spinning process can be worked can, if necessary, cooling the spun Filaments, peel off at a speed in the range from about 100 to 8000 m / min, preferably from 1000 to 5000  m / min and subsequent further, usual Process steps, such as drafting if necessary and depending on the intended further use Wirrablage, Summary on yarns or cables, texturing, Fixation, cut into staple fibers, characterized that a material is spun, the predominantly one filament-forming polymer or polycondensate and 0.01 to 30 wt .-% (preferably 0.01 to 10, in particular 0.1 to 5% by weight), based on the weight of the material, organic or organometallic charge control agent contains. 27. Process for producing the electret fibers of the claim 1 by columns of fissile multilobal fibers, the along the fiber axis extending segments of the Electrolyte contained or by matrix dissolution of an "Island in the Sea" filament of its island areas consist of the electric material, or by splitting a foil from the electret material, thereby characterized in that the Elektretwerkstoff predominantly a filament-forming polymer or polycondensate and 0.01 to 30 wt .-% (preferably 0.01 to 10, in particular 0.1 to 5% by weight), based on the weight of the material, organic or organometallic charge control agent contains. Nonwoven fabric consisting of or containing electret fibers of Claim 1. 29. Dust filter consisting of or containing a nonwoven fabric of claim 28. 30. Use of the electret fibers of claim 1 to Production of nonwovens. 31. Use of the electret fibers of claim 1 to Production of dust filters.