DE1910000A1 - Process for the separation of flocked thread material and in particular for the separation of flocked carbon threads - Google Patents

Description

Dr. O. DITTMANN

PATENT LAWYERS

Munich 9, Bcreiiaranger 15.

Telephone 29 73 69

Description of the company's patent application

COURTAULDS LIMITBD
18, Hanover Square
London W. τ / England

concerning

Procedure n for the separation of flocked thread material, and in particular for the separation of flaked carbon threads

Priority: February 27, 1968 No. 9375/68, UK

Parallel oriented carbon thread of short staple length embedded in a polymer matrix provide a useful form of a self-lubricating surface and are the subject \ prior German Patent Application No. * P 18 10 182.I ₀ The present invention relates to the production of carbon short staple fiber bodies for the preparation of such material are appropriately oriented.

According to the invention, a method for producing a body with a short apple fiber length includes cutting

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of the carbon fibers on a short staple length »deposition a carrier by electrostatic flocculation, 80 that the deposited flake is essentially made up of parallel Threads normal to the support, and attach the flokkung in the orientation by means of a binding agent

Carbon threads can be produced by using organic thread material with regard to special conditions Temperature and the surrounding atmosphere. In this way, the threads can be brought to one temperature in a first stage in the range of about 200 to 300 ° C in an atmosphere which is inert, but preferably oxidizing Has properties, and they can then be heated to a temperature above 1000 ° C in an inert atmosphere will. If graphitized threads are to be produced, so a further retention treatment is necessary Temperature above 2000 ° C and preferably above 2500 ° 0 also takes place in an inert atmosphere. Carbon threads, which are made by using polyacrylni.tril- -fädeii subject to this procedure are so particularly good Products. In the method according to the invention, carbon threads that have been produced by treating organic thread material such as polyacrylonitrile thread is used after the first swej of the heat treatment stages, although it is in some cases it is preferred to use graphitized threads use,.

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Preferred for use in the method according to the invention Carriers are glass fabrics and essentially any knitted or woven textile material such as nylon, polyester, Polyacrylonitrile, viscose and natural fibers such as cotton. Auoh film material can be used · So In one form of the invention, short staple carbon fibers are applied to a substrate in an electrostatic flocculation process deposited in a fabric or film, where they are in their Orlen »- A bonding agent such as an adhesive or a curable resin coating can be used to secure the coating. Suitable glue are for example polyurethane or dispersions of polyacrylic ester; where, however, oriented carbon threads into one If the polymer matrix is to be incorporated, it may be preferred to use a liquid polymer coating as the binder To use form or in the form of a precursor or a corresponding prepolymer.

Carbon threads are available in relatively short or long staple lengths, but they can also be obtained in continuous thread form. Carbon threads suitable for use in the process according to the invention should be very have a short stack length and must therefore be cut will. Suitable stack lengths are, for example, in the length range from 0.5 to 5 mm, although in some cases up to up to 10 mm can be used. Such lengths can be cut by tying bundles of longer threads into one

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Cutting machine of the guillotine type or with rotating knives on clock t. It is important that the threads after cutting are all of substantially the same length; ever The better a uniform length can be achieved, the more suitable they are for their intended purpose. carbon ad en do not show "a lot of thread-to-thread friction, like that that it is usually not necessary to use a friction reducing agent Finish to use. The humidity of the procedure conditions is of some importance? in this way one can make carbon threads of this type in an electrostatic Field. More uniform in relatively dry conditions to fly"

In electrostatic flocking, the threads to be flocked are charged by bringing them into contact with a charged surface. The charged stain is repelled from the charged surface when it has assumed its charge and can then be collected on a grounded surface, onto which it is deposited with threads normal to the grounded surface. Accordingly, it is preferred that the carrier or the binder or both be electrically conductive. The binder can for example have antistatic properties or the carrier can be provided with an antistatic coating if it is not itself conductive. If the binder has to be hardened or otherwise made hard, this can be done immediately after the

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Deposition of the flake can be carried out on it. The carriers coated with carbon dioxide in this way can be impregnated with a polymer material in accordance with the manner described in German patent application P 18 IO 182.1 and shaped into shaped objects for bearing surfaces.

The invention is illustrated by the following example: A woven glass fiber fabric (example 4-thread satin veil) is coated with a thin layer of an acrylic adhesive (C. Lennig Primal KH). The coated glass fabric is introduced into a flocking apparatus in such a way that the fabric is brought into contact with the earthed surface and with the adhesive layer on the charged surface. The flocking apparatus is essentially a generator with high potential; a quantity of 2.5 mm flake of carbon thread, made in an automatic guillotine cutter, is applied to the charged surface. Immediately thereafter, the fibers are attracted towards the earthed surface, but are effectively trapped in the adhesive coating and cut perpendicular to the surface. When a sufficient amount of flake has been deposited, the coated fabric is removed and the adhesive layer.

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used stable surfaces, as described in the German Fatent application F 18 10 182.1.

Similar coated fabrics are also made using a woven glass cloth , plain weave and nylon 6 woven fabric, plain weave. In any case, satisfactory resistant surfaces are obtained.

Claims

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Claims (1)

Claims ·) A method for producing a body old short Star · pelfasern, characterized in "that carbon fibers into short staple length, they atischeidet on a carrier by means of electrostatic flocking, so that the deposited flake consists of of substantially parallel filaments normal to the support" and the flake is attached in this orientation by a binding agent. 2. The method according to claim 1, characterized It is not possible to use carbon threads that are manufactured by heating an organic thread material to a temperature in the range of about 200 up to 500 ° C in an oxidizing atmosphere and then carbonizing at a temperature above 1000 ° C in an inert atmosphere. 3. The method according to claim 2 »marked thereby net that one uses carbon threads, which are essentially have been graphitized by heating to a temperature above 2000 ° 0. - 7th 909845/1396 4 · Method according to one of Claims 1 to 3 »thereby characterized »that one carbon threads used, which have been made from organic thread material, the whole or mainly of polyacrylonitrile duration. 5 «The method according to any one of claims 1 to 4, characterized characterized in that a knitted or woven textile material is used as the substrate. 6, method according to claim 5 »characterized in that that the textile material used is made of glass, nylon, polyester, polyacrylonitrile, viscose or cotton, 7. Method according to one of Claims 1 to 4 _f, characterized in that a film is used as the carrier. 8ο Method according to one of claims 1 to 7, characterized characterized in that one is used as a binder uses an adhesive or a curable resin coating » 9. The method according to claim 8, characterized in that - · - η e t that a polyurethane or a dispersion of one or more polyacrylic esters is used as the binder « 909845/13 9 6 10t A method according to any one of claims 1 to 9 _f characterized in that carbon ens t offäden of a tape slopes S in the range of 0.5 5 The ram applies τβΓ- <, 11 «Method according to one of claims 1 to 10, characterized in that an electrically conductive substrate is used ₀ 12. The method according to any one of claims 1 to 11, characterized characterized »that an electrically conductive binder is used. - 9 909845/1 396