IE45577B1 - Mixtures of synthetic fibres of filaments containing carbon black - Google Patents

Abstract

The dark colour of antistatic, carbon black-containing synthetic fibres or yarns can be made to disappear visually by using carbon black-containing fibres that are composed of acrylonitrile polymers or copolymers and have a boil-out shrinkage of 10 to 70%, in particular 20 to 50%, and mixing 0.1 to 20% by weight of those fibres with 99.9 to 80% by weight of carbon black-free fibres composed of polyamide, polyester, polyalkene or poly(mod)acrylics. On bringing about the boil-out shrinkage, for example in tufted material, the dark colour of the carbon black-containing fibres is then hidden.

Description

Thia invention relates to fibre and filaaeat nistures consisting of high-shrinkage'synthetic fibres or filaaeats containing carbon black and standard synthetic fibres or filsaeats free from carbon black of, for osaapls, a polyamide, polyester, poly-alkylene or poly(sod)aerylis, to a prooess for their production and to testila articles produced from then.

It is generally toom that synthetic fibres or filesents of polyacrylonitrile, polyamide, polyesters Io or Boiyalksaas end sheet-fora textiles produced fr&a thsa have ths undesirable property of besoming electrostatically charged and this property restricts their use in the textile or industrial sector. A troublesome charge such as this is developed when the surface resistance of the TO fibres amounts to more than 10 ohms, as measured at - S3°G/5O$ relative humidity. A variety of different measures have already been proposed to obviate this disadvantage„ la many cases, attempts are made to improve tho conductivity of tha fibres or filaments by subjecting them or the textiles ga produced from them to a surface treatment with antistatic preparations. Unfortunately, ite antistatic effect obtained la this way is often not permanent.

Another widely used method is to six the fibre or filesent substrates with specific conductivity-improving - 2 = polymers which almost alwayscontain polyethylene oxide units as their effective component, and subsequently to spin the mixtures from the solution or melt. For producing antistatic fibres or filaments of the type in question, this involves different processing technology in relation to the production of non-modlfied fibres or filaments and, hence, additional effort.

A recent prooess for reducing the electrostatic charging of sheet-form textiles, such as floor coverings . for example (cf. for example Chemiefasem/Textilindnstrie, January, 1976, page 14), is based on the addition of metal fibres to normal fibres of the above-mentioned type and spinning them together, but unfortunately this frequently gives rise to considerable difficulties. The high price of the metal fibres ls also a certain obstacle, as also is the deterioration in light colours affecting the textile articles produced from the mixture.

One relatively well established method of imparting high surface conductivity to polymeric systems is to add carbon black to them before they are processed. Examples are thermoplastic materials or elastomers containing additions of carbon black, such ae for example poly(ethylenevinylacetate), natural rubber, styrene-butadiene rubber, polychloroprene, nitrile rubber, etc. The quantities of carbon black used may make up as much as 50# by weight of the mixture of solids (of. for example Advances Chem.Ser. 134 (1974), pages 171-183). 45877 Filaments modified with cartoon black are already 5 in use in the textile sector. In their ease, improved antistatic behaviour is generally obtained. However, it. is important for any textile application of filaments modified with carbon black to avoid an unfavourable visual 10 impression caused by the modificiation of the articles with carbon black» Although carbon-jacket filaments (epitropics) .are known (Textile Manufacturer, July 197%, pages 19-23), they can only be added to filament yarns of normal polyester or polyeside and in addition, ‘ lead'to an unfavourable appearance of light colours in.the case of solid-colour yarns and fabrics. In 15 addition, filaaents consisting of a carbon eore/polyeaide jacket have been processed ia admixture with polyamides (Shesaiefasern/Textllindustrie, January, 1976» page 1%). la. this ease, too, however, the addition is confined solely to filament7yarns (3CF), - If has now-been found, that mixtures of 5 to 85^ go by weight of.carbon black and 95 to 75$ by weight of aa . acrylonitrile eopclyser,- whsa spun together iron s.solvent which dissolves the acrylonitrile copolymer, gives--filaaents or fibres which, ia their fully shrunkstate and depending - 25 ' 1 upon- theytyge and quantity of carbon black- used, have -- - . permanent surface2resistant of. 10 to 10 ohms, as measured &t 25°C/50$ relative air humidity, If has 'also bass found that these acrylic fibres or filaments esataising carbon black need only be mixed in a proportion -- » 4 “ _ - of from 0,1 to 20^ by weight of tbe total mixture with other filaments or fibres, for example of poly(mod)acrylic, polyamide, polyester or polyalkene, in order to produce sheet-form textiles, such ae floor coverings, woven and knitted fabrics, whioh have adequate antistatic properties for practical purposes.

Zn addition, it has surprisingly been found that the dark spots in the textile article caused hy the acrylic fibres or filaments containing oarbon black can be rendered less noticeable or even completely avoided hy using shrinkable carbon-black-containing fibres or filaments. The reason for this is that, whereas mixture effects are obtained, as expected, hy adding normally shrinking acrylic fibres or filaments containing carbon black, there is quite unexpectedly very little, if any, change in the optical effect in oases where corresponding medium-shrinkage or high-shrinkage fibres or filaments are used, providing measures are taken to ensure that these carbon-black-containing medium-shrinkage or high-shrinkage fibres and filaments are able to shrink fully ia the textile article. Thus, textile products produced from fibre yarn or filament yarn mixtures of this kind, such as for example floor coverings, woven and knitted fabrics and also nonwoven*, do not show any streakiness after a shrinkageinitiating treatment such as, for example, boiling, dyeing, streaming, printing, lataxing and any other finishing process taking place at elevated temperature (approximately 100*c). - s 48 577 In particular, this makes it possible to obtain light colours without in any way detracting from the visual appearance of the textile.

It is clear that this principle mentioned in regard to acrylic filaments in particular applies equally to any shrinkable synthetic fibres or filaments containing carbon black.

Accordingly, the present invention provides fibre and filament mixtures consisting of from 0.1 to 20# by weight and preferably of froa 0.2 to 5# by weight of carbon—black-containing synthetic fibres or filaments having a boiling-induced shrirjtage of frcm 10 to 70%, and of from 99.9 to 80% by weight and preferably of frcm 99.8 to 95% by weight of synthetic fibres or filaments of polyamide, polyester, poly (mod)acrylic or polvalkene.

The quantity of carbon black in the filaments or fibres containing carbon black generally amounts to between. 5 sad 25#, by weight and preferably to between 10 and 20# by weight, based on the total solids content. 2o In order to obtain as good as possible a turnout of the finished textile, the boiling-induced shrinkage of the filaments or fibres containing carbon black amounts to between 10 and 70# and preferably to between 20 and 50#.

By the addition of; carbon black, the surface resistance of the fully shrunk fibres or filaments is reduced • -< ip' from an original level of more than .10 nhm3 to values ' 3 11 of-froa about 10 to 10 ohms (as measured at 23°C/5G$ . . «β «. 48877 relative hualdity after 10 washes In accordance with DIN 54 345, sheet 1).

The carbon-black-containing filaaents or fibres ay consist of polyamides, of polyesters, of polyalkenes, but preferably of acrylonitrile(oo)polyaers.

The invention is described by way of exaaple in the following with reference to the production and processing of high-shrinkage (aod)aerylic fibres containing carbon black.

To produce the acrylic or modacrylic fibres containing oarbon blaok, oarbon black is aixed with and finely dispersed, by high-speed stirring, in a solution of an acrylonitrile copolymer, optionally in the presence of snail quantities of an eaulslTier to facilitate dispersion. The solution is then spun under the known conditions of dry spinning or wet spinning. On the other hand, it is also possible to prepare a separate aixture of the total quantity of carbon black required and part of the acrylonitrile copolyaer required in the corresponding solvent, to filter the suspension and then to add a streaa thereof in the oorreot ratio to the dissolved residual quantity of polyaer either just before the spinneret through a static aizer or even in a kettle. Suitable solvents are any solvents known to the ezpert such as, for exaaple, the preferred solvents dimethyl foraaaide and diaethylacetaaide. Solution, promoters are not necessary. The tows are then processed into filaments in known manner by washing out the solvent - 710 drawing, preparing, drying, crimping and steaming, or by additional process steps into fibres,, In order to obtain final shrinkage levels of from 10 to 70$ low dryer temperatures are applied aad only very little steam is admitted during the steaming process, or alternatively the steamer is operated as a drying unit, (She quantity aad type of carbon black used determine the surface resistance of the modified acrylic fibres or filaments. It is, of course, preferred to use carbon blacks which specifically show es improved conductivity in relation to other carbon blacks , although it is also possible to use other types of carbon black, The carbon blacks generally used have an average particle disaster of from 10 to 60 oja, preferably from 15 to 4s0 aja, and a surface (¾}. of from 60 to 300 a2/®»' ο preferably from 90 to 260 to /g.

The quantity of carbon black used should amount to at least 5$ by weight aad. to at most 25fs by weight, based. oa the sum total of the solids used, because it is only with quantities' within this range that the intrinsic - conductivity of'normal fully shrunk acrylic fibres or filaments —13 is increased from approximately 10 J Siemens to between io31 and, 10”^ Mieseas, leaving the minimum taxtile values (strength,. elongation, etc, ) intact, Any acrylonitrile copolymers knows to and used by tho expert for the production of synthetic acrylic fibres . or filassata may be used .for the purposes of the invention, - 8 25 43577 The acrylonitrile oopolyaers in question are primarily substrates of which at least ©5% by weight consist of acrylonitrile and which, in addition, contain (aeth) acrylates, vinyl carboxylate,(aeth)allyl oarboxylates, (iso)butenyl oarboxylates, aaleatss, fuaaratss, (aeth) acrylonaaides and N-substituted derivatives, vinyl ethers, styrene and derivatives, alkenes, aethaorylonitrile, also dye-receptive additives such as, for axaaple, (noth) acrylic aoid, itaconic acid, aaleio acid, vinyl-, (aeth)allyl-,styrsne-sulphonic acid, sulphoalkyl(aeth) acrylates,vinyl-, (aeth)- allyl-phosphonic aoid or Nsulphoalkyl(aeth)acryiaaide.

Since the total content of acrylonitrile is theoretically reduced by the addition of earbon black, the total acrylonitrile contest of the fibres or fileaents aodified with oarbon black can easily be less than ©5% by weight, depending upon the quantity of carbon black added and the type of acrylonitrile oopolyaer used* It is, of course, also possible to use acrylonitrile oopolyners with an acxylonitrile content of far less than 8SJ( by weight, i.e. so-called aodaorylics, for exaaple those of aorylonitrils or vinyl or vinylidene halide with acrylonitrile contents of 60 or 40% by weight.

The shrinkage level of the types containing the oarbon blaok aay be favourably influenced in particular by the coaonoaer content of the substrate.

When spinning these fibres from earbon black/polyaer mixtures the spinning velocity advantageously is from ISo-jJoo m/fflin, preferably 2oo m/mln and the stretching 3o kratio is from 1 t 1.8 to 1 t 3.o, preferably 1 s 8,0» 1 ι 2.5.

These carbon blaok acrylic fibres or filaments are peraanGntiy antistatic, even after rcpeatod washing, with 5 IT surface resistance values of from Nr to 1© ©tes in their fully shrunk state, as measured at 23°C/50jC relative air humidity ia accordance with SIN 54 345, sheet X.

For producing other high-shrinkage synthetic fibres or filaments containing carbon black, it is possible to use,'for example, polyeaprolaotaa, salyhexEHQthylana adipic amide, polysmina unfieeomolc acid, poly-(is®phthaloyl-Qphoayleas disnlde) palypyrrolidone, polyethylene glycol . .torephthslate, polysyclohexans-l,4-dis@thyl©l terephthalate, pelybstyleE® glycol terephthalate, polypivalolactcne, poly(l-hyfircsyethosy-4-earboxy)-beasen8, polyethylene or poly- , propyieaso. ' ' ' Bo£liagdec@d shrinkage levels of sore than 50% say bo obtained particularly easily by using polyesters . or mixed polyamides ae ths fibre or filament substrate.

\ In order to obtain textile articles, preferably floor coverings,' but aloe knitted fabrics, woven fabrics and aon-wovsns, with inclusion of these special fibres or filaments, spinning fibre or filanemt yarn mixtures arc prepared from 99,3 to 805 by weight of aliphatic or aromatic polyamide, polyester, paly(Eod)aorylie or gelyalkene fibres or filaments ahd from 0.1 to 20£ by weight of the - - high-shrinkage oarbbtt bisek-aontaisihg synthetic-fibres ®r .filaments,. -After &. shrinkage-initiating treatment,. sueh as the standard aad necessary finishing processes, . : - for.sxespls dyeing, the sheet-form textiles produced .- - 104SS77 from these filament yarn or spinning fibre mixtures by conventional textile processes are in no way affected in their appearance by the presence of the mediumshrinkage or high-shrinkage black fibres or filaments fully shrunk in the finished article, whereas normalshrinkage fibres or filaments containing carbon black are noticeable in the finished article.

If desired, antistatic additives may also be used during the finishing, if any, of the particular textile constructions. Examples of the fibres or filaments used as the main constituent of the fibre or filament mixtures are fibres or filaments of poly-f-oaprolaotam, polyhexairethylene adipic amide, polyaminoundecanoic acid, polypyrrolidone, poly(iso-phthaloyl-m-phenylene diamide), polyethylene glycol terephthalate, polycyclohexane-1,4dimethylol terqihthalate, polybutylene glycol terephthalate, polypivalolactone,poly(l-hydroxyethoxy-4-carboxybenzene), polyethylene, polypropylene, poly(aorylonitrlle methacrylate), poly(aorylonitrile vinylacetate), poly(acrylonitrile vinyl20 idene chloride) or polyacrylonitrile vinyl chloride).

Poly-i-oaprolactam, polyhexamethylene adipic amide, polyethylene glycol terephthalate, polycyclohexane-1,4dimethylol terephthalate, poly(acrylonitrile methyl acrylate) or polypropylene are preferably used.

The finished textile articles obtained from the fibre or filament mixtures show the properties characteristic of the substrate fibres or filaments such as, for example, - ll· 455Ή textile-technological data, utility values, gloss, appearance, dyeahility etc. and, in addition, are permanently antistatic. In the case of floor coverings for example, this is reflected in the fact that any one walking over a floor covering, even in rooms with low air humidity, will feel no adverse effects, for example electrical shocks, as a result of electrostatic charging.

For example, individual charges of from 200 to at most 1800 volts are measured in accordance with DIN 54 345, sheet 2, on velvet-pile carpets produced in this way and provided with an antistatic reinforcing finish. With other textile articles such as knitted pullovers for example, the permanent antistatic finish prevents the familiar unpleasant effects of charging and discharging such as, for exaaple, crackling and sparking, during dressing and undressing. Another advantage is that these permanently antistatic articles can also he dyed in light colours. Another feature worth mentioning, especially In regard to floor coverings produced in accordance with the invention, is that their sensitivity to water stains is no higher than that of floor coverings consisting entirely of the normal synthetic fibres and filaments mentioned here.

The carbon black content of the fibres/filaments may be indirectly determined by elemental analyses. In the case of carbon-black-containing(mod)acrylic fibres -12 45377 for example, their nitrogen content is determined and compared with the corresponding value of fibres of the same type, but free from carbon black. The carbon black content is obtained by calculating the difference.

In order to determine boiling-induced shrinkage, individual capillaries are fastened at their ends to clips and are vertically suspended, the capillary length being determined. They are then immersed in boiling water for 2 minutes, after which their length is remeasured. The difference between the original length and the final length is calculated as a percentage of the original length. The measurement is made 10 times and the results are averaged out.

In the case of fibres, filaments, yarns and sheetform textiles, the antistatic effect is tested by measuring the electrical resistance values in accordance with DIN 54 545, sheet 1, and, in the case of floor coverings, additionally in accordance with DIN 54 345, sheet 2.

The textile properties, the utility values of the textile articles and also the fastness values (fastness to light and fastness of dye finishes) are determined in accordance with the known test specifications.

Sensitivity to water stains is determined as follows: ml of desalted water are poured onto a carpet, followed after complete drying in air by evaluation on the grey scale according to DIN 54001.

The production of the carbon-black-containing - 1345877 antistatic acrylic fibres and filaments, which are subsequently mixed with polyamide, polyester and polyacrylic fibres and processed into textile articles, is described in the following.

EXAMPLE I a) Preparation of a carbon black starting mixture 18.2 kg of dimethyl formamide (BMP) and 5.1 kg of a commercial-grade conductive carbon black, of the type used for electrically conductive lacquers and plastics, . with.an average particle size of 23 mp and a specific surface area of 15o m2/g (Cor&x L, a produce of Degussa, Frankfurton-Main) (Corax is a Trade Mark) ware vigorously stirred for 24 hours Wiile cooling. Thereafter, 11.3 kg of a 29.5% by weight solutian of am acrylonitrile copolyaer in DMF were added to this suspension, followed by stirring for. another 3 hours without cooling. The acrylonitrile copolymer consisted of by weight 'of acrylonitrile, 5.5$ by weight of methylacrylate and 0.5$ by weight of sodium mothallyl sulphonate and had-s K-v&e of83 (Fikentseher, Cellulosechomie 13, · Ϊ932, page 58). In order to remove swollen particles, this mixture was forced through a cloth-covered filter press. b) . . Dry spinning .1kg of the filtered starting mixture, 4.7 kg of the above acrylonitrile copolymer, 7.1 kgof DMF and 0,1 kg of iso-nonyl phenol polyglycol ether were heated for 2 hours to 80eC to dissolve the polymer. For spinning, the suspension was pumped through a. heat exchanger in which: it was heated to approximately 130°C, to a spinneret- containing ' β « 45S77 bores each with a diameter of 0.25 mm. The spinneret was situated at the upper end of a 4.5 metres long spinning duct with a diameter of 280 mm. To remove the solvent from the filaments leaving the spinneret, the duct was heated to 210°C and exposed to a stream of hot air (380°C) flowing at a rate of 40 m5/h· The filaments were taken off at 180 m/minute and wound into package form.

The spinning denier was 32 dtex. The tow was stretched in a ratio of 1:2.3 in hot water(7o°C) and the solvent adhering to it was washed out. The tow was then prepared, dried to 70°C in the absence of shrinkage, crimped and cut into fibres 150 mm long. The fibres were then freed from residual moisture by blowing with air.

The fibres showed the following properties: Denier: 17.7 dtex (determined by weighing out) Carbon black content (determined by N-analysis ):18,45 by weight.

Boiling-induced shrinkage: 45% Surface resistance of the fully shrunk fibres (after 10 washes): 7 x 105 ohm.

To produce filaments, the same procedure was adopted and a crimped tow was obtained. 0) Production of a velvet - pile fabric A yarn (oount 3.8/l) was spun from a mixture of 0»5% by weight of the above-described fibre with 99.55 by weight of a nylon -6 fibre with a denier of 20 dtex, A semiworsted yarn, in which the component fibres were - 15 4S577 homogeneously mixed, was readily obtained by conventional worsted-spinning techniques without any additional aids.

A carpet with a pile weight of 600 g and a pile depth of 6 mm was produced from this yarn in a 1/8» tufting machine.

The velvet-pile carpet thus produced was·dyed a very light beige with a combination of standard acid dyes, the shrinkage of the carbon-black-containing fibres also being initiated during dyeing, and was then coated on its back with a standard stabilising composition and with a foam, both based on SBB-la'tex, 4$ of a standard antistatic agent having been added to the precoating compound to improve its intrinsic conductivity. Evaluation of the . aarpet- did not reveal any deterioration in its optical appearance attributable to the presence of black fibres.

Antistatic behaviour; individual charges of less than 500 volts were measured.

Comparison. Example For comparison with the above-mentioned floor covering, a carpet of the 20 dtex nylon-6 fibre was produced under exactly the same conditions, except that the fibre according to the invention was not added. Evaluation of this.'carpet revealed an optical appearance entirely identical with that of the above-mentioned floor. . covering.. Testing of the fastness values and utility values of both carpets also produced entirely identical values, . neither carpet being sensitive to water stains. Antistatic behaviour; individual charging values>7000 volts. - 16 _ . ' In order to test the antistatic effect for permanence, both carpets were subjected to a continuous walking test over a period of 3 months. Individual charging values after this period: Carpet of Example 1 ,s400 volts Carpet of the Comparison Example: >6500 volts EXAMPLE 2 a) Starting mixture An acrylonitrile copolymer/carbon black mixture was initially prepared in the same way as in Example 1 using the same polymer. The carbon black used was of the type which is also used inter alia for dyes, paper, carbon paper, etc,, with an average particle size of 29 mp and a surface of 96 a2/g (Printex 140, a product of Degussa, Frankfurt-onMain). (Printex is a Trade Mark). b) Spinning 17.6 kg of the filtered carbon black starting mixture, 7.8 kg of DMF, 5.2 kg of the acrylonitrile copolymer characterised in Example 1 and 0.1 kg of the polyglycol ether mentioned in Example 1 were vigorously stirred for 2 hours at SO°C. As in Example 1, the suspension was pumped to a spinneret with 96 bores, each 0.25 am in diameter, which was situated at the upper end of an 8.5 metres long duct with a diameter of 280 mm. The duct was heated to 170°C, the amount of air flowing through it amounted to 40 a^/h and the temperature of the air wae 300°C. The filaments were run off at 200 a/minute and wound into package fora. 45877 . The tow. was processed into fibres under the same conditions as in Exaaple 1. The fibres had the following properties: Denier: 15·5 dtex 5 Cut length: 150 es Carbon.black content:· 18.8 $ by weight Boiling-induced shrinkages 41 0 Surface resistance of the fully shrunk fibres (after 10 washes): g 5 x 10 ohms. 10 -c) Production of a tufted article ’. · A mixed yam (count 3.5/1) was produced from a mixture . of 5 0 of the fibre described is b) viith 97 % by weight of a polyacrylonitrile fibre (94 % of acrylonitrile, 5.5 0 of methylacrylate, 0.5 0 of sodium methsllyl .sulphonate) with a 15 denier of 17 dtex, .and was processed into a tufted article with a pile, weight.of 850 g/a2 and a pile depth of 10 mm. She polyacrylonitrile fibre had been previously flock-dyed as '’oliye0 colour with standard basic dyes. It was latexed (is the ease way ae described in Example 1), during which 20 the shrinkage of the carbon-black-containing fibre was initiated, and coated. Visual evaluation: no noticeable bleak fibres. Antistatic behaviour: individual charging values <1000 volts. Comparison Example 25 For comparison,; 4537 7 the antistatic behaviour, the tests results were identical with those of Example 2: individual charging values >>- 5000 volts.

EXAMPLE 3 52,8 kg of an acrylonitrile copolyaer/carbon black starting mixture prepared in the same way as in Example 2, .4 kg of DMF and 17.6 kg of the repeatedly mentioned acrylonitrile copolymer were vigorously stirred for 3 hourB at 80°C. For spinning, the suspension was pumped through a heat exchanger, in which it was heated to 130°C before entering the spinneret, to the spinneret containing 180 bores, each with a diameter of 0.3 mm. This spinneret was situated at the upper end of the spinning duct used in Example 2 which was heated to 170°C and through which flowed 40 m^/h of air at a temperature of 290“C. The filaments were run off at 200 m/minute and wound into package form.

The spinning denier amounted to approximately 20 dtex.

As already repeatedly mentioned, further processing was carried out after stretching in a ratio of 1:2.5 by washing, preparation, drying at 65°C in the absence of shrinkage, crimping, cutting and blowing with air.

The fibres had the following properties: Denier: 7.9 dtex Cut length: 100 mm Carbon black content: 17,1 # by weight Bolling-induced shrinkage: 39 # Surface resistance of the fully shrunk fibres (after 10 washes): Q x 10 ohms.' A yarn (count 6/2) was spun from a mixture of 1 5 by weight of this fibre and 99 5 by weight of nylon-6 fibre (12 dtex). A floor covering with a pile weight of 720 g and a pile depth oi 7 ffl was produced from this twisted yarn, in which the. two fibres were homogeneously mixed. It was dyed in the same way as described in Example 1, ths shrinkage of the carboa-blsek-eoataining fibre being released during dyeing. However, the bach of the floor covering was stabilised by coating with an SBR latex to which no. antistatic agent had been added for increasing intrinsic conductivity.

She optical appearance of the floor covering was also not impaired by the presence of the black fibre. Antistatic behaviour: individual charging values “C 3600 volts. Comparison Example For comparison with the above-mentioned floor covering a carpet was produced under exactly the same conditions from the 12 dtex nylon-6 fibre. Antistatic behaviour: individual charging values 12000 volts.

EXAMPLE 4 (does not correspond to the invention) 14.2 kg of a starting mixture of carbon black and acrylonitrile copolymer prepared in the same way as in Example 2, 9-9 kg of DMF, 5«9 kg of the acrylonitrile' copolymer described in Example 1 and 0.05 kg· of tho aromatic polyglycol were stirred for 2 hours at 80°C. This was followed by spinning in the same way as described in Example 2 - „ 20 25 45377 The tow was stretched in a ratio of 1:2.5 in hot water, after which the DMF was washed out with hot water. The tow was then prepared and dried at lJO’C with 20 $ permitted shrinkage. The tow was then crimped, cut and briefly treated with superheated steam in order to remove the remaining residual shrinkage.

The fibres showed the following properties: Denier: 16.5 dtex Cut length: 150 mm Carbon black content: 15.1 $ by weight Residual shrinkage: 1.4 $ Surface resistance of the fully shrunk fibre (after 10 washes): 5 x 1010 ohms.

The yarn (count 3.8/1) was spun from a mixture of 5 $ 15 by weight of the described fibre and 95 $ by weight of a nylon-6 fibre. The tufted article produced with a pile weight of 600 g/m2 and a pile depth of 6 mm was dyed dark red and provided with the same back finish as described in Example 3. Visual evaluation: the non-shrunk black fibres are clearly noticeable. The mixture effect obtained could possibly he of Interest. Antistatic behaviour: individual charging values: O 2200 volts. With the same back finish as in Example 1: individual charging values Z* 300 volts. Comparison Examples for comparison with the above-mentioned floor covering, a carpet was produced under otherwise the same conditions from the 20 dtex nylon-6 fibre. Antistatic behaviour: individual “ 21 charging values: ^>11,000 volts (finish as im Example 3). After the same back finishing treatment as in Example 1, the individual charging values amounted to 6500 volts. EXAMPLE 5 .1 kg of the acrylonitrile copolyaer/carbon black starting mixture produced is accordance with Example 1, kg of the same acrylonitrile copolymer as in Example 1 and 35 kg of K®1 were vigorously stirred for A hours at 80°C. For dry spinning, the suspension was pumped through a heat exchanger, in which it was heated to I20°C, to a 180-hore spinneret with individual bore diameters of 0.25 mm.

The spinning duct was 8.5 metres long and280 aa in diameter. The duet temperature was adjusted to 180°C and air heated to 3θ0°0 was passed through the duct at a rate of 40 s^/h. The filaments were run off at 200 m/minute.

Thetow was stretched in a ratio of 1:3.0 in hot water, after whioh the solvent adhering to it was washed out. The tow was then prepared, dried in the absence of shrinkage at 70eC, crimped, cut into fibres 100ana long and 60 ma long end the residual moisture in the fibres was removed by blowing with air.

- The fibres showed the following properties: .

Denier: 3.5 dtex Cdrhes black contents 9.8 # by weight Boiling-induced shrinkage: 37 # ' Surface resistance of the fully shrunk fibres (after 10 washes) x ip (to. - --. .. --. : -:. τ; / Ξ - 22 “ 2 45S77 a) Production of a tufted article A yarn (count 2.8/1) was spun fro» a homogeneous mixture of 2 Jt by weight of this fibre (cut length 100 mm) and 98 Ji by weight of a polycyclohexane dimethylol terephthalate fibre with a denier of 6.7 dtex. A tufted carpet with a pile weight of 850 g and a pile depth of 10 mm was produced on a 5/32 . tufting machine. The carpet was then dyed a light Berber shade with a standard combination of dispersion dyes in the presence of a carrier, the shrinkage of the carbon-blackcontaining fibres being initiated during dyeing. The carpet was then stabilised and coated in the same way as described in Example 1. The black component fibre was not noticeable on evaluation. On the contrary, a completely uniform harmonious optical impression was obtained. Antistatic behaviour: individual charging values 800 volt*.

Comparison Example For comparison, a floor covering was produced under otherwise the same conditions from a cyclohexyl dimethanol terephthic fibre with a denier of 6.7 dtex which had not been mixed with the fibre according to the invention.

Antistatic behaviour: personal charging values ^>500 volts, b, Production of a knitted fabric After the production of a homogeneous fibre mixture, a mixture of 1 $ by weight of the described fibre and 99 Jt by weight of a polyacrylonitrile fibre (dtex 3.3, 60 mm) with the same composition as in Example 2, which had previously been flock-dyed a gold shade, was spun by 3-oyclinder spinning into a yarn (count 28/2) which was made 48577 up.into a dense knitted fabric. ' Visual assessment after fixing in the usual way (steaming), during which shrinkage of the carbon-black- . containing fibre was initiated, revealed a completely uniform 5 colour turnout. In other wards, the optical impression was not impaired by.the black component fibres. Antistatic behaviours a surface resistance of 6 x IO10 ohms was measured after ten domestic washes. Comparison Example 10 For comparison, a knitted fabric was produced, under exactly the same conditions from a polyacrylonitrile fibre to which the fibre according ta. the invention had not been 'added. Antistatic behaviour? surface resistance (after 15 . 10 domestic washes) /’IO1-’ ohms. Example 6. A tufted carpet produced, in accordance with Example 1 was not piece-dyed, but instead was screen-printed in the usual way (four colour printings green/olive/brown/white). The shrinkage of the csrbon-black-containing fibre was 20 initiated by the necessary steaming process. Visual assessment? uniform optical impression, no black fibres noticeable. Antistatic behaviour: individual charging values 500 volts, - . Comparison-Example 25 Individual charging values.of 4800 volts were measured on the tufted carpet produced under otherwise the same conditions from nylon-6 fibre (20 dtex) to which the - fibre.accordingto the invention bad not been added. . . . . -- - 24 - -45577 EXAMPLE 7 0 by weight of the crisped tow produced in accordance with Example 1 (individual denier dtex 18) was doubled with 99 0 by weight of a nylon-6 filament yam of dtex 2670 f 126. The mixture of both filament yarns produced in this way was wound into package form and subsequently processed under the normal conditions for BCF yarns (bulked continuous filament) into a loop pile carpet with a pile weight of 500 g and a pile depth of 5 mm. After winch vat dyeing in a light beige colour, during which the carbon-blackcontaining acrylic fibre was fully shrunk, the carpet was stabilised (as described in Example l) and coated.

Ylsual evaluation: uniform appearance, no black filaments noticeable. Antistatic behaviour: individual charging values < 700 volts.

Comparison Example Personal charging values of the comparison carpet produced without the fibre according to the invention, but under otherwise exactly tbe same conditions: 5300 volts.

Claims (18)

1. CLAIMS:1. A fibre or filament mixture comprising from 0.1 to 20% by weight of synthetic fibres or filaments containing carbon black and having a boiling-induced 5 shrinkage of from 10 to 70%, and from 99.9 to 80% by weight of synthetic fibres or filaments of polyamide, polyester , polyalkylene or poly (mod) acrylic.

2. A fibre or filament mixture as claimed in Claiip 1, wherein the carbon black content of the 10 synthetic fibres or filaments containing carbon black is from 5 to 25% by weight, based on the sum total of solids.

3. A fibre or filament mixture as claimed in Claim 1 or 2, wherein, in their fully shrunk state, 15 the synthetic fibres or filaments containing carbon 3 11 black have a surface resistance of from 10 to 10 ohms, as measured after 10 washes and at 23°C/5O% relative humidity in accordance with DIN 54 345, sheet 1.

4. A fibre or filament mixture as claimed in 20 any one of Claims 1 to 3, wherein the synthetic fibres or filaments containing carbon black are (mod)acrylic fibres or filaments.

5. A fibre or filament mixture as claimed in any one of Claims 1 to 4, wherein the fibres or 25 filaments not containing carbon-black are fibres or filaments of poly-e-caprolactam. 45877

6. A fibre or filament mixture as claimed in any one of Claims 1 to 4, wherein the fibres or filaments not containing carbon black are fibres or filaments of polycyclohexane-1 ,4-dimethylol terephthalate. 5

7. A fibre or filament mixture as claimed in any one of Claims 1 to 4, wherein the fibres or filaments not containing carbon black are fibres or filaments of an acrylonitrile copolymer.

8. A fibre or filament mixture as claimed in Claim 1, 10 substantially as hereinbefore described with reference to any of the Examples.

9. A process for the production of a fibre or filament mixture, wherein from 0.1 to 20% by weight of synthetic fibres or filaments containing carbon black and having a 15 boiling induced shrinkage of from 10% to 70% are mixed with from 99.9 to 80% by weight of synthetic fibres or filaments of polyamide, polyester, polyalkylene or poly(mod)acrylic.

10. A process as claimed in Claim 9, wherein the carbon-black content of the fibres or filaments containing 20 carbon-black is from 5 to 25% by weight, based on the sum total of solids.

11. A process as claimed in Claim 9 or 10, wherein, in their fully shrunk state, the synthetic fibres or filaments containing carbon black have 27 4 5877 after 10 washes, and at 23°C/50 5 relative humidity in accordance with DIN 54345, sheet 1.

12. A process as claimed in any one of Claims 9 to 11 wherein the synthetic fibres or filaments containing carbon black are (aod)acrylic fibres or filaments.

13. A precess as claimed in any one of Claims 9 to 12, wherein the fibres or filaments not containing carbon black are fibres or filaments of poly-s-caprolaetam.

14.. .A process as claimed in any one of Claims 9 to 12, wherein the fibres or filaments not containing carbon black are fibres or filaments of polycyelohexane-l,4-dimethylol terephthalate.

15. A process as claimed in any one of Claims 9 to 12, wherein the fibres or filaments not containing carbon black are fibres or filaments of an acrylonitrile copolymer.

16. A process as claimed in Claim 9 , substantially as hereinbefore described with reference to any of the Examples.

17. . A fitee or filament mixture whan produced by a process as claimed in any one of Claims 9 to 16.

18. Textile structures with permanently antistatic properties comprising a fibre or filament mixture as claimed in any one of Claims 1 to 8 and 17.