Hoechst Aktiengesellschaft

Hoechst Trevira Gmbh & Co Kg

Hoechst Gmbh

Acordis Kehlheim Gmbh

Richard Neuert

Holger Jung

Peter Klein

Gerhard Stein

Bernd Huber

Georg-Emerich Miess

Hans-Tobias Macholdt

Werner Groh

Jorg Dahringer

Werner Bruckner

Uwe Kampschulte

Jutta Cardinal

Dieter Eichenauer

Wilbert Kemper

This invention describes high-strength fibers with high initial moduli from homopolymers or copolymers comprising at least 70% by weight repeating acrylonitrile and/or methacrylonitrile units, and a process especially adapted for their preparation, and their use, especially as reinforcing materials or for producing filters or friction coatings. The fibers according to the invention have a strength of more than 100 cN/tex and an initial modulus of more than 15 N/tex (based on 100% elongation).

High-strength high-modulus polyacrylonitrile fibers, method for their production and use

Cut-resistant fibers comprise a filler having a Mohs hardness of at least 3 and a fiber-forming material comprising selected aromatic polyamides soluble in polar aprotic organic solvents. The fibers are useful for manufacturing protective clothing.

Cut-resistant aramid fibers, yarns comprising these aramid fibers and

Fibers having a tenacity of more than 80 cn/tex and a filament linear density of more than 8 dtex which contain as the fiber-forming material an aromatic polyamide which is soluble in organic solvents and spinnable from isotropic spinning solutions. The fibers can be used for example as reinforcing materials, as heat-resistant insulator materials, for producing filter fabrics or as insulating materials.

Aramid fibers of high strength and high linear density, production

Described are aramid fibers with a spin finish comprising

Spin finished aramid fibers and use thereof

A process for producing mass-colored fiber or film, comprises the steps of:

Mass-colored formed structures based on aromatic polyamides,

A process for producing fibers or films by the steps of: a) preparing an aromatic polyamide by polycondensation of dicarbonyl dihalides or mixtures thereof with at least two diamines in N-alkyllactams as a solvent, the polycondensation being of at least 90 mol %, based on the total amount of dicarbonyl dihalides in the reaction mixture, of compounds of the formula I or mixtures of such compounds Hal--OC--Ar.sup.1 --CO--Hal (I) with at least 90 mol%, based on the total amount of diamines in the reaction mixture, of compounds of the formula II and optionally III or mixtures of such compounds H.sub.2 N--Ar.sup.2 --NH.sub.2 (II), H.sub.2 N--Ar.sup.3 --NH.sub.2 (III) where Ar.sup.1, Ar.sup.2 and Ar.sup.3 are independently of each other a bivalent aromatic radical, the proportion of structural repeat units in the aromatic polyamide derived from the compounds of the formula II, based on the proportion of the structural repeat units derived from the compounds of the formulae II and III, being at least 50 mol %, and said aromatic polyamide is soluble in organic solvents, b) forcing the solution of the aromatic polyamide obtained in step a) through dies of the desired cross-sectional shape at temperatures from 40.degree. to 120.degree. C. to form fibers or films, c) removing the organic solvent in a conventional manner to produce solvent-leaner or -free fibers or films sufficiently mechanically stable and nontacky for further processing. The process of the invention omits the customary neutralization after the aromatic polyamide has been prepared.

Production of fibers or films using specific forming solutions and the

Two-component loop yarns are composed of core and effect filaments, at least part of the core component consisting of aromatic polyamides, wherein the aromatic polyamides contain the structural repeat units of the formulae I and II

Two-component loop yarns comprising aramid filaments, manufacture

A process for maintaining or increasing the tensile strength of fibers of aromatic copolyamides which are formed from a major portion of para-monomers and are soluble in organic aprotic and polar solvents. The process involves storing the fibers in alkaline media after production by wet or dry spinning processes, after treatment of the dry or wet spun fibers, and storing the fibers in an aqueous environment having a pH of at least 10. The tensile strength of the fibers is retained or increased.

Process for maintaining of improving the mechanical properties of fibers

Aromatic polyamide staple fiber bundles of improved dispersibility in viscous matrices and production of fiber-reinforced composites Described are bundles of aromatic polyamide staple fibers having a staple length of at least 1 mm which have been provided with an effective amount of an agent which enhances the cohesion of the fiber bundle. The staple fiber bundles are held together by the adhesive before mixing into a matrix material and separate into individual fibers on mixing into the matrix material. There is no need for special mixing apparatus.

Aromatic polyamide staple fiber bundles of improved dispersibility in

Aromatic copolyamides, production thereof, formed structures and production thereof Described are aromatic copolyamides comprising the structural repeat units of the formulae I, II and III ##STR1## where Ar.sup.1, Ar.sup.2, Ar.sup.3 and Ar.sup.4 are independently of one another bivalent aromatic radicals whose valence bonds are disposed para or comparably coaxial or parallel to each other,

Aromatic copolyamides, production thereof, formed structures and

Aromatic polyamide compositions with improved electrostatic properties, formed structures produced therefrom, and use and production thereof. Described are compositions comprising an aromatic polyamide which is soluble in organic solvents and from 0.01 to 30% by weight, based on the weight of the composition, of an organic or organometallic charge control agent. The compositions can be used for producing formed structures, in particular fibers; these fibers are preferably used for producing webs which can be used for producing dust filters.

Aromatic polyamide compositions with improved electrostatic properties,

A method monitors and measures the uniformity of tows with mechanical sensing elements in the course of production on a tow line. The tension of the running tow is measured upstream of a transport roll arrangement and is utilized as a measure of the uniformity of the tow. Irregularities in the tow result in tow tension determination outside a predetermined tension range, and when the determined tension measurement is outside that range the irregular tow portions are remove. Also, the frequency of tow tension determination outside a predetermined range may be used as an indication of tow quality and for removing substandard tows.

Monitoring the uniformity of tows

Novel aramid fibers with a spin finish having useful properties for the production of sheet materials are described in the present application. The aramid fibers contain at least three elements including an anionic antistat based on phosphoric, phosphonic, or phosphoric and phosphonic esters; a compound of the formula .sup.1 --COO--(CH.sub.2 --CH.sub.2 --O--).sub.x --R.sup.2 ; and a compound of the formula R.sup.2 --O--(R.sup.4 --O).sub.y --R.sup.5, wherein R.sup.1 is alkyl or alkenyl, x is an integer from 2 to 20 R.sup.2 is hydrogen or alkyl, R.sup.3 is alkyl or alkenyl, y is an integer from to 8, R.sup.4 is ethylene, propylene, or butylene, and R.sup.5 is alkyl.

A process and apparatus for guiding a continuous moving tow in synthetic fiber manufacture. The profile (the thickness distribution and width) and the position of the tow are continuously sensed in a non-contact manner and an appropriate electrical signal is generated. This electrical signal is used to control the profile and the position of the tow in such a way that its profile and position stay within predetermined target value ranges. The tow geometry is preferably sensed using a CCD camera, while the tow geometry is controlled using tow-engaging deflecting means. In this way it is possible to optimize tow profile and position, for example for entry into a stuffer box (FIG. 1).

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Winkelhaid, Germany

Richard Neuert