DE2337103B2 - Antistatic synthetic two-component thread - Google Patents

Description

Low electrostatic charging is described in U.S. Patent 3,639,807. In such carpets, however, the wire can bend and entangle and as a result of efficacy a ^bU The 'use of distributed in fibers of electrically conductive carbon black door antistatic textile applications in the US patents 2845962 and 3706195 beschneben; However, these fibers have poor mechanical and physical properties, such as brittleness and poor toughness, and therefore may not survive processing into normal everyday objects or use in such, as is pointed out in US Pat. No. 3582448 in the electrically conductive coatings containing carbon black on synthetic threads for antistatic purposes

The use of electrically conductive, thinly insulated with electrically non-conductive synthetic fibers Wire for the production of carpets from

rJie ^ Vr 3475898 and 3558419

describe synthetic antistatic, made from coat and core composed of filaments in which either polyethylene oxide is dispersed in the core or the Core made from a special polyether-polyamide block copolymer consists. In some applications, however, it has been found that both embodiments to an insufficient reduction of the electrostatic charging capacity of the target Thread u & J textile lead.

The invention relates to a new antistatic synthetic two-component thread from core-sheath-Tvp. consisting of an endless. electrically non-conductive sheath made of a synthetic thermoplastic thread-forming polymer, which surrounds a core made of a synthetic thermoplastic polymer and at least 50 ",, the thread cross-sectional area occupies, and thereby characterized in that the core disperses in the thermoplastic synthetic polymer, electrically contains conductive soot, is itself electrically conductive and has a direct current potential of 2 kV has an electrical resistance of less than 0.4 x 10 6 "ohms / cm and the jacket optionally is molecularly oriented.

For use in low concentrations in a mixture with other threads, the core of the threads according to the invention preferably has a resistance of less than 0.4 · 10 ⁹ ohm / cm under a direct current potential of 2 kV.

Materials of high electrical conductivity for the core, i.e. those containing more than 20 percent by weight Containing carbon black are preferably used for threads, in which the portion of the sheath is at least 80%.

The invention provides antistatic threads used in light colored fabrics can be. For such purposes, the proportion of the sheath in the thread is at least 90%, and the coat is matted to partially cover the black core, so that the thread can be (as described below, determined) has light reflectance greater than 20%. Of the preferred matted thread contains 2 to 7 weight percent titanium dioxide pigment in the sheath.

By suitable choice of the polymer for the jacket, antistatic threads are obtained according to FIG Invention that can be colored as desired and fluffy together under the most varied of conditions can be made and suitable for purposes of use

_w 'nd, where the toughness of the coat is important.

Surprisingly, the threads according to the invention, although they predominantly consist of the non-conductive sheath, which acts as an electrical insulator, can be used as a very small component of fabrics, yarns or other textiles, which mainly consist of other synthetic fibers or threads require antistatic protection, regardless of the relative humidity used for antistatic purposes, e.g. B. to prevent the accumulation of static electricity. The invention therefore also relates to antistatic yarns and staple fibers consisting of a mixture of non-conductive synthetic threads with threads according to the invention, the latter being present in a proportion of less than 20 percent by weight of the mixture. Concentrations of threads according to the invention in such mixtures can have an excellent antistatic effect, even if the threads according to the invention are contained in the mixtures only in low concentrations of less than 2 \ ; however, the mixtures preferably contain at least about 0.05 percent by weight of these threads. In such mixtures, the polymer of the thread jacket can be dyed together with the non-conductive threads; In particular, the polymer of the thread jacket can belong to the same polymer class as that from which the non-conductive threads are made.

The particularly preferred products according to the invention are electrically conductive fibers for manufacture of carpets with an electrostatic charging capacity of less than 2.5 kV according to the test for the electrostatic charging capacity of carpets explained below. These fibers show an excellent combination of electrical conductivity and antistatic properties, without having an undesirable color.

The invention also includes a method of making the synthetic antistatic of the invention Bicomponent threads made by composite spinning of two synthetic thermoplastic Polymers with different electrical conductivity, the polymer for the thread jacket is thread-forming and the proportion of this polymer is at least 50 percent by volume, as well as collecting the sponneren threads, characterized in that the material used for the electrically conductive The core of the thread is an electrically conductive polymer which is dispersed in carbon black and is used as a material for drn Thread sheath an electrically conductive polymer used and, if necessary, the threads, if necessary with heating, stretched so much that they assume a strength of at least 1.5 g / den.

To further explain the invention, reference is made to the drawings.

Fig. 1 is a schematic cross section through a consisting of sheath and core thread according to the invention;

Fig. 2 is a schematic cross section through an antistatic yarn which is made from a Gemisi.h from Threads according to FIG. I and non-conductive, synthetic 6s see threads best fit.

In the illustrated in Fig I Fadenquerschnitt5 the core 1 consists of electrically conductive us Ruß3 which is embedded in a polymer 4, and is surrounded by the group consisting of a non-conductive polymer shell. 2

According to FIG. 2, threads with the cross section shown in FIG larger number of non-conductive, synthetic threads 6.

The "non-conductive sheath" of the threads according to the invention consists of a synthetic, thread-forming polymer. The threads have an electrical surface resistance of more than 0.4 · 10 ¹² Ohm / cm, determined by contact with the thread surfaces at low DC voltages, for example 100V or less. Homofibers made from such sheath materials also have resistances of more than 0.4 · 10 ¹² ohm / cm, determined by the same method. Linear polymers of high molecular weight that are processed into threads of sufficient strength and toughness for the application are referred to as "thread-forming".

Compared to the nicely designed coat of high electrical resistance, the core of the filaments has a low resistance and a high electrical resistance Conductivity once electrical contact has been made with it. The electric one Contact with the thread core can either be with the help of electrodes that penetrate the sheath and come into direct contact with the core, or made with the help of surface contact electrodes be, in which case one applies such a high voltage that the current through the The thread sheath penetrates and an electrical contact with the core is established as a result. if one works with surface contact electrodes according to the latter method, occurs when the Direct current voltage to several hundred and especially several thousand volts a sudden Increase in the amperage, as described below in the explanation of the test procedure. Once the electrical conductivity has been established in this way, the electrical current flows Current usually continues, even if the voltage is subsequently reduced, provided that only the contact of the thread with the electrodes of the measuring device is not changed.

The low electrical resistance of the core of these threads is an indication that the core of the entire measured thread length is electrically related. Related interruptions of the core between the measuring electrodes tend to have a higher electrical resistance noticeable, approaching that of the mantle. Occasional related interruptions of the core are not particularly detrimental to the antistatic behavior of the threads according to the invention. Preferably, however, the core should over the entire length of the fibers or threads according to the invention regardless of whether it is staple fibers or filaments, be uninterrupted. It is essential that the thread core is uninterrupted over such a length of the thread that the bereflendt Thread together with other such antistatic threads make an effective antistatic one Network forms. Threads that meet the specified level of electrical Have conductivity of the core, offer an effective antistatic protection.

The thread jacket can consist of any desired, extrudable, synthetic, thermoplastic, thread-forming polymers or copolymers. These include polyolefins, such as polyethylene and polypropylene, acrylic polymers, polyamides and polyesters of thread-forming molecular weight. Particularly suitable polymers for the thread coat -are the polyamides obtained by condensation of diamines and dicarboxylic acids or of amino acids, the polyesters, especially those of low and _to terephthalic acid or isophthalic acid Olykolen. such as ethylene glycol, tetramethylene glycol and hexahydro-p-xylylene diol. as well as the polyacrylonitriles. These polymers can be modified in a known manner with regard to their dyeability, for example by introducing basic or acidic dye sites through copolymerization, in order to make it easier to mix them and dye them together with other dyed or dyed synthetic fibers.

The tensile strength properties and other physical properties of the threads according to the Invention depend primarily on the polymer of the sheath for threads of high strength the material used for the jacket is polymers of higher molecular weight and those that are stretched to a greater degree. Although undrawn filaments according to the invention for some Applications can have sufficient strength, drawn threads are preferred.

The thickness of the jacket must be sufficient to provide the core with the necessary protection, e.g. B. Strength as well Resistance to heat and abrasion, and to hide the core when required. in the In general, the jacket should have a thickness of at least 3μ: the use of larger jacket thicknesses depends on the titer or diameter of the thread that can be used. For normal Sheath thicknesses suitable for textile thread denier are in the range from 8 to 22μ. Maybe if the Threads z. B. must be processed at high temperatures. /. B. by bulging in the hot gas or Steam nozzle or by texturing, it is essential that the thread jacket have such a high melting point Has. that it does not soften or melt under the processing conditions. For such purposes, it is preferred to use the jacket a higher melting polymer, such as polybexamethylene adipamide, to steep of polycaprolactarn.

The thread core consists of a dispersion of electrically conductive carbon black in a thermoplastic Polymer. The core material is primarily taking into account electrical conductivity selected based on processability. The carbon black concentration in the core of the thread can be 15 to 50%. With Soot concentrations of 20 to 35%, which are preferred, result in high electrical conductivity, while the processability is still maintained to a sufficient extent. The material for the Core preferably has a resistivity of less than 200 ohms / cm and in particular of less than 50 ohm / cm. The use of known, specially made for this purpose, elec- 6s Irish, more conductive types of carbon black make it possible to reduce the required amount of carbon black to one Minimum.

Since plastic masses are stiffened by high soot loading, the generally softer, lower-melting polymers (which also have a correspondingly lower glass transition temperature than materials for the thread core compared to the stiffer, higher-melting polymers are preferred. The polymer of the core preferably has a lower melting point and a lower freezing temperature than that of the thread jacket this facilitates processing (e.g. prevents breakage of the thread core and an interruption in the distribution of the soot particles), while the electrical conductivity in the thread core and the finished thread is maintained. that leaves fell ^one of Werkstoffdes thread core spun itself to Fäder, and therefore the polymer for the core line need not be a fiber-forming polymer. that is to Fadenkernpolymerisat under the required conditions for the spinning of Polymerisatmantels heat-resistant & nd be extrudable. Suitable polymers for the mass of the thread core in which the carbon black particles are embedded are, for example, polyamides, polyesters and acrylic polymers. Polyether, polycaprolactone and polyolefins (e.g. polypropylene, high and low pressure polyethylene). These polymers can be mixed with other substances such as oils or waxes to facilitate processing. Copolymers, such as those made from ethylene and vinyl acetate, can also be used.

The carbon black can be distributed in the fiber core polymer by known mixing processes. One must ensure that the carbon black is distributed so evenly in the fiber core polymer that the mass without excessive mixing and the associated decrease in electrical conductivity can be extruded.

For satisfactory spinning, it is important to remove volatile substances from the polymers that the Soot has been added to be removed prior to melt spinning. This can be during or after the collaboration of the carbon black with the polymer. It can also be useful to use such polymers e.g. Can be dried under low vacuum at 68 ° C for 16 hours. Furthermore, the usual precautionary measures are used, to prevent oxidative decomposition during spinning, e.g. by removing the oxygen in the polymer lines with the help of Excludes inert gas, etc.

The cross-sectional area (which is directly related to the filament volume) of the electrically conductive The core of the composite thread just needs to be sufficient to give the thread the desired electrical power Resistance and may only need to be 0.5 percent by volume. The lower one Limit depends primarily on the processability to form sheath-core threads of sufficient uniform texture with still sufficient cohesion of the thread core with the low ones Thread core volumes.

The spinning of the threads according to the invention can be used in conventional spinning systems for spinning Sheath-core threads are made from two polymers, with the different properties of the two Components to be considered. The threads can be easily spun using conventional spinning methods with polymers, as described, for example, in US Pat. No. 7936482

Further instructions for spinning polyamides can be found in U.S. Patent 2,989,798.

The threads can be drawn by conventional methods; however, care must be taken avoid sharp corners that could break or damage the core of the thread. In general one preferably uses the hot stretching process, in which the thread during the Stretching is additionally heated. This will further soften the core material and stretch it relieved. The antistatic threads can be made with conventional, synthetic, undrawn threads be padded and stretched together.

The threads according to the invention can easily be produced with a tenacity of at least 1.5 g / den, which is completely sufficient if the threads a! s quantitatively smaller component with others Threads are mixed. The threads preferably have an elongation at break of at least 10%. but less than 150%. on. The properties of mixed textiles depend primarily on the properties of the other threads. For general purposes, the threads according to the invention have one Filament denier of less than 50 and preferably less than 25 den.

The threads can have a round or non-round cross-section, an eccentric or concentric arrangement of cladding and core as well as combinations of these features. Because of the concentric Arrangement achieves the best protection and the best concealment of the thread core. The delicacy of the The core of the thread contributes greatly to its concealment. and threads with fine kernels can be dyed in or patterned textiles are used that do not otherwise have any other covering that covers the core of the thread Feature. You can also use the core of the thread, if necessary. with the help of an opacifier in the form of cavities or in the form of a white, solid, powdery matting agent. like titanium dioxide, conceal in the jacket. Out of round. ζ B. multi-leaf cross-sectional shapes carry on to cover the thread line.

The variables that affect the masking of the yarn core, include the thickness and the dyeability of the sheath, the ratio of sheath tu core, the concentration of matting agents such as titanium dioxide, which are in the sheath as well as voids, due to separation between the sheath and core materialize and can occur when it comes to oriented threads whose sheath and core consist of dissimilar polymers, in which, for example, the sheath consists of a polyamide and the core of polyethylene.

Without a covering thread jacket to hide the black color, they are filled with soot Fibers generally have a light reflectance of less than 5%. Reflectivity values of more than 20%, as can be achieved according to the invention, represent a very significant improvement, because it avoids that light-colored textile fabrics through the threads according to the invention a darker one Take on color.

The threads according to the invention are capable of all types of textile fabrics. like knitted. Carpets, Woven and nonwovens to give excellent anti-static protection. You can conventional additives and stabilizers, such as dyes and oxidation inhibitors, contain. she can handle all types of textile processing such as crimping, texturing, washing, bleaching, etc. be subjected. They can be combined with staple fiber yarns or filamentary yarns and as staple fibers or be used as filaments.

The threads according to the invention can be used in the course of yarn production (e.g. during spinning, drawing Texturing, plying, rewinding, yarn spinning) or in the manufacture of the textile materials whose threads or fibers are united. Care should be taken to ensure that the antistatic threads suffer as few fractures as possible. For example, when handling the relative lengths and shrinkage The antistatic threads and the other threads are coordinated to ensure good workmanship availability and the desired packability, subject availability. To achieve rotatability or texturability

Description of the test procedures
Electric resistance of the thread core

The electrical resistance of the thread core is determined from the current intensity measured when a voltage of 2 kV is applied to a 5.08 cm long Prolx. A suitable device is the 15 kV "Biddle Dielectric Tester" (James G. Biddlt Company, Plymouth Meeting, Pennsylvania, USA). A three-thread bundle is just clamped between two electrodes 5.08 cm apart and sufficient voltage is applied to observe a current flow (eg 1 to 4 kV) As soon as current flows, the voltage is set to 2 kV and the current strength is calculated according to Ohm's law R = EI. If the current strength is 2 kV in a 5.0 cm long sample, for example 10μΑ, the resistance for the three threads is 0.4 10 * Ohm / cm. The resistance per thread is then 1.2 10 ⁸ Ohm / cm. In order to achieve current flow in the above experiment, the voltage should be increased gradually in order to avoid a sudden increase in the current strength, which could burn out the threads. Burnout can easily be determined visually (on broken, melted or charred threads), and such samples must be disregarded in the determination. The resistance of threads that are shorter than 5 cm can be measured by adjusting the distance between the electrodes accordingly.

Reflectivity

The light reflectivity, namely the brightness or whiteness of the sample compared to a standard made of magnesium oxide, with a photoelectri see reflectometer for sure. A suitable device is the photoelectric reflectometer, Ma dell 610, with a green color mixing filter (catalog no. 6130), "Search Unit Model 610-Y", and a white lacquered working standard plate which is calibrated so that it has a reflectivity of 70 to 75% has (Catalog No. 6162) available from Photovol Corporation, 95 Madison Avenue, New York, N.Y 10016. The electrically conductive thread sample to which the Measurement is to be carried out, aul 5.08 cm ■ 7.62 cm black mirror card file (in about six layers of thread) wrapped around the reflectance on the cards (as an average from 10 measurements).

Percentage of soot in the core
Customary analytical methods can be used to determine the soot concentration in the material of the thread core. A method suitable for polyethylene containing carbon black is described or can be derived from ASTM test standard D-1603-68. This is the thermogravimetric method which is suitable for use in the absence of non-volatile pigments or fillers other than carbon black.

Percentage of the core in the thread

The easiest way to determine the percentage by volume of the core is to determine the cross-sectional area of the black core by measuring below the Compare the microscope with that of the entire thread. This can easily be done at about 400 times Carry out enlargement. With round threads you can easily determine the size from the ratio of the square of the core diameter to the square of the total thread diameter. One takes the mean of ten determinations to compensate for any irregularities. For threads with With a non-circular cross-section, the calculation can easily be carried out using measurements made on microphotographic Recordings of thread cross-sections have been carried out at a known magnification are.

When the polymer of the shell is so different from that of the core Solubility differs in that it differs through exposure to solvents can be removed, the percentage of the core can be determined gravimetrically, by dissolving the coat and adding the weight of the insoluble core to the weight of the original Sample compares. So you can, for example, to dissolve a jacket made of polyhexamethylene adipamide Use formic acid from a polyethylene core.

Determination of the specific resistance
of the core material

The specific resistance of the core material containing carbon black is determined by measuring the direct current resistance over a length of 5.08 cm of a 2.54 cm wide and 0.25 mm thick film strip. Such films can easily be produced by pressing a powdery or tablet-shaped sample of the core material between two aluminum foils in a press heated above the melting point of the core material under a pressure of 1400 kg / cm ² for 1 to 2 minutes. After cooling, the aluminum foil is peeled off the sample foil, and strips 2.54 cm wide and about 6.35 to 7.62 cm long are cut out of the sample. The thickness of the foil is measured with a micrometer. A strip is clamped between two copper electrodes that are 5.08 cm apart and the Glerchstromwidefstand is determined with an ohmmeter. The specific resistance of the film in ohms cm is calculated from the reading of the measuring device in ohms as the product of the measured resistance, multiplied by the width, multiplied by the thickness, divided by the length of the sample, all expressed in cm .

Example I.

There are concentric sheath-core threads mil

■ ο a jacket made of polyhexamethylene adipic acid amic with a relative viscosity of 45 and a polyethylene containing 20 "electrically conductive carbon black core made. The soot is an »extra-conductive * Oil furnace soot (non-volatile carbon 98 "", volatile substances 2 ° ". Particle size 30 rnp, lowest specific electrical resistance in the dry state), available from Cabot Corporation, 125 High Street, Boston. Massachusetts 02110. USA. This Carbon black is described in the technical reports "S-8" and "1518/173" from the company mentioned. the Carbon black dispersion is made by making the carbon black

. at 120 ° C with high pressure polyethylene (density 0.916: Melt index 23; »Alathon 2821« of the applicant) married in the dough mixer. The soot is slow and the mixture is poured 10 minutes after the addition of carbon black has ended. This polyethylene is due to selected for its softness. (Other suitable resins are high pressure polyethylene with a density of 0.916 and a melt index of 11.9 alone or in a mixture with 15 to 40 ",, oil or wax) The melted carbon black mixture is filtered through a sieve with a mesh size of 0.15 mm and extruded. Press films show excellent carbon black distribution and electrical conductivity with one

resistivity of 12.7 ohm cm. Using this material for the core, sheath-core continuous filaments, namely three monobloc with a filament denier of 65 denier, m ^; * spun at a speed of 389 m min, whereby the total

titer is kept constant and the volume of the core is reduced by changing the pumping speeds that the samples shown in Table I are obtained. The core volume is determined by the Pump speed determined and through analysis

of the cross-section of the threads at a magnification of 200 times. It becomes a three-hole stainless steel spinneret Steel is used, which feeds the polymers for the jacket and the core concentrically and individually until they are on the front face of the spinneret

step out. Throw an oath capillary used, QBi the Kempoiymerisat to the front surface of the spinneret to guide, where it emerges, surrounded by the shell polymer. The threads have a thread denier spun out of 65. Then they will be with a

Speed of 183 m / min drawn at a maintained at 150 ⁰ C, curved hot plate to das3,06fache. The physical and electrical properties of the game are shown in Table I.

Table I.

volume, %
^? adentiter, the.
^? estigkett, g / den
elongation. ",

Sample no.

50
21.4
1.5
26.2 40
20.6
f, 9
36.4

3 4th 5 25th 18th 12th 21.4 21.2 19.9 2.4 2.T 3.4 30.3 54.7 574

continuation

I. 2 Sample no
3 4th 5 Initial modulus, g / den
Electrical resistance χ ΙΟ ⁹ ,
Ohm / cin / thread *)
Breakdown voltage. kV
Electrostatic charging capacity
of the carpet. kV (according to example 2) 15.3
2.0 17.9
0.98
1.6
3.0 25.1
2.64
3.4
2.8 20.3
1.57
3.4
3.0 25.2
5.24
4.6
2.6

*) derechnet from the current strength in μΑ. determined at 1 kV

The sample carpets in Table I are made from a commercially available 204-thread bulk carpet yarn Polyhexamethylene adipamide with a gel titer of 3700, consisting of three-winged endless bottles, made with a pile height of 1.27 cm. A strand of electrically conductive thread (approx 0.56 percent by weight) is pinned with the carpet yarn during unwinding and then for pimpling used. The visibility of the electrically conductive threads in the carpet decreases with decreasing Volume of thread core decreases noticeably. .

Example 2

Production of the thread jacket polymer

30th

A stainless steel vessel is charged with 317.5 kg of an aqueous solution containing 50 weight percent hexamethylene diammonium adipate, whereupon 721 g of a 10 weight percent solution of manganese (II) hypophosphite [Mn (H ₂ POj) ₂ ] in water. 70 g of 25 weight percent acetic acid and 100 ml of an 11.2 percent silicone antifoam agent are added. The batch is concentrated by evaporation to a solids content of 75 percent by weight and transferred to a stainless steel autoclave equipped with a stirrer. The air is displaced from the autoclave by inert gas and the contents are heated to 200 ° C up to a pressure of 17 atm. 14.83 kg of a 49 percent strength by weight aqueous titanium dioxide slurry are then added with stirring. The heating is continued until the temperature reaches 273 ° C. and the pressure is then gradually released to atmospheric pressure. The polymerization is continued according to Example 1 of US Pat. No. 2163636. After the end of the polymerization reaction, the molten polymer is sirang-pressed in the form of 6J-mm strands. After cooling with water, the strands are cut into 6.3 x 4.7 mm chips, which are suitable for remelting in a spinning device. The flakes have the following properties:

Relative viscosity 43.5

(NH ₂ ) 46.0 equivalents per 10 ^ g

TiO ₂ 5.04 "/ ,,

Mn (H ₂ PO ₂ J ₂ 0.048 \

Thread core polymer

Composition 6s

Polyethylene 70 percent by weight

Electrically conductive carbon black
according to Example 1 30 percent by weight

Polyethylene

High pressure polyethylene (density 0.916; melt index 23 according to ASTM D-1238) manufactured by E. I. du Pont de Nemours and Company, for injection molding. The polyethylene contains 50 ppm antioxidant, to improve its heat and aging resistance.

Manufacturing

A 3.7-1 capacity two-blade dough mixer is charged with 1905 g of polyethylene and 816.5 g of carbon black. The whole is mixed for 30 minutes at 140.degree. ^C. , extruded, sieved through a sieve with a mesh size of 0.15 mm and shaped into tablets.

The product has the following properties:

Specific resistance
(a film cast at 180 ° C) 2.9 to 4.2 ohm cm

Soot content 30.2 ""

Moisture content 0.04 ° ,.

If the moisture content is higher than 0.1 "", the tablets should be spun for 24 hours be dried at 70 ° C in a vacuum.

The spinning

The polymers for the shell and the core are placed in a screw melt spinning machine Use of the spinneret arrangement shown in US Pat. No. 2936482 to be concentric Sheath-core threads are spun.

The jacket polymer is fed through at a rate of 19.8 g / min (calculated from dei Capacity and speed of pomp ") and the core polymer at a high speed of 0.7 g / min (calculated from the capacity and speed the pump) so that a concentrically arranged composite thread is obtained, which consists of 96 percent by volume of sheath and zi 4 percent by volume of core the temperatures of the polymers for the shell and the core in the screw melt direction set as follows:

Zones of the

Sdineckenschmetz-

vibration

Above
center
Below

TemperatOT des Manteipolymerisats

149
285
28 «

Temperature of

fCernpofynierissts

120
222
265

The spinning block temperature is 293 ° C. Pie hopper RSr the two polymers are mi ^f inert gas flushed.

The relative viscosity of the jacket polymer when it emerges from the spinneret (during free fall) is 56; the increase in relative viscosity is the result a further polymerization of the dried polyhexamethylene adipamide in the screw melter. The spinning speed is 814 m / min. The spun yarn collected is gray and has the following properties:

Reflectivity

IO

Finishing on the yarn ~ l <0 "/ _n Core, volume percentage 4 Coat, percent by volume 96 Titer of the spun bundle, the 60 ¹ p

Number of threads per bundle 3

Reflectivity 37 to 40 %

The stretching

The electrically conductive dreifädige yarn 60 is stretched in the draw-twister at a winding speed of 366 m / min and a temperature of 18O shoe ^'J C to 2.7 times.

The drawn yarn has the following properties:

Thread count 3

Strength, g the 3.8

Elongation at break. ",. 35

Modulus, g / den at 10 percent

Stretching 13

Electrical resistance of the

Core bundle 1.8 · 10 ⁷ ohm-cm

35

Common puffing

A strand of 3400 denier 1400 denier 1400 denier, 4-cavity, 4-cavity hollow filament polyamide strand. as described in British Patent 1,292,388. is puffed together with a strand of the electrically conductive yarn at one point on the hollow filament spinning machine. The yarns are placed in a heating box under a tension of 10 to 20 g on the last wrap around the heat setting roller. before they reach the bulk nozzle, united. The Wärtnefixicrwalze located at 195 "C, and the yarn speed is 1084 m / min. The common bulking is carried out by passing the yarn through an operating under a pressure of from 8:44 kg / cm ² at 240 ° C bulking in Belgian Patent 573,230 The yarn is then guided with a random, three-dimensional, curvilinear crimp with an alternating S and Z twist, and the yarn is then cooled and wound up.

The tensile properties of the bulked yarn are approximately the same as those of the parent yarn. Sham-dyed carpets with flat knobs (pile height 1.27 cm, weight per unit area 0.996 kg / m ⁴ , fabric density 4 mm, 7 stitches per 2.5 cm), made from yarns that contain the electrically conductive threads (sample) and from yarns, which contain no electrically conductive threads (control), with a commercially available polypropylene adhesive as a carpet base, and which are rubberized with conventional latex, provide the following values for the electrostatic charging capacity at 20 "relative humidity and 21 ^D C:

5 sample
control Electrostatic charging
ability of the carpet 1.5 to 2, OkV
10.2 to 11 kV

25th

30 This test conforms to AATCC test standard 1 34-1969 with changes made by the Carpet and Rug Institute in September 1971 .

In the raw carpets and the shine-dyed carpets, the three-ply 20-denier strands made of electrically conductive threads give a very faint bluish tinge. Colored carpets from continuous filament yarns Bausch, the electrically conductive threads included, show in most monochrome tones no difference and only minor differences in certain monochromatic light colors. e.g. yellow, orange and pink when compared to the control carpet.

Optionally, the threads according to the invention can be in the form of staple fibers. e.g. in quantities from 0.5 to 5 percent by weight, together with non-conductive elements Staple fibers in carpet yarn \ crv \ endei.

Example! 3

This example shows that you have to be careful! must pay attention. that the threads according to the invention do not lose conductivity when they are drawn.

There are threads with an eccentric sheath-core arrangement with a sheath made of polyhexamethylene adipamide. which has a relative viscosity of 44 and 0.3% TiO ₂ , and a core of polycaprolactam (relative viscosity 45: 31.8 equivalents of NH _{2 end} groups per 10 ⁶ g) with a carbon black content of 20 ". The carbon black is the same as in example 1. The proportion of the core in the RMcn is 40 percent by volume. The three-thread yarn is spun with a linear density of 79 denier.

The yarn is cold drawn on a drawing pin. As Table 11 shows, the electrical contradiction increases of the cold drawn yarn with the draw ratio. If the thread is without a pin on a domed heating plate is "hot drawn" at 160 ° C, there is practically no increase in resistance. It is assume that when the yarn is heated in a heated drawing zone during drawing, the core will do so is softened to the extent that a break in the core or an interruption in the distribution of the carbon particles. which is necessary for conductivity. is avoided.

Tables

Horizontal bar ratio Electrical resistance
of the core
Ohm / cm / 3 threads 1 (undrawn)
1.5
3.0 0.6 I0 ⁸
2.4 IO ¹²
2.0 ■ 10 ^u
2.75-10 "*) 3.0 (hot drawn)

* 1 Calculated: one / one height on the three hides.

is

Example 4
Sheath polymer

Polyethylene terephthalate flakes with a relative viscosity of 23 + 2, determined on 0.8 g of polymer in 20ml hexafluoroisopropanol at 25 ° C.

Core polymer

22 ",, electrically conductive

Screw melting
zane Temperature of
Sheath polymerisais
"C Temperature of
Core polymers
C. Above
center
Below 249
281
289 206
250
265

Polycaprolactam with
Soot according to example t.

Manufacturing

A predispersed slurry of 22.680 kg of electrically conductive carbon black, 86.180 kg of caprolactam and 83.910 kg of distilled water is prepared in a mixing vessel with stirring at 50 to 55 ° C. This slurry is charged to a stainless steel autoclave with a capacity of 227 kg and provided with a stirrer. The autoclave is cleared of air and filled with inert gas, whereupon heating begins. The temperature of the autoclave is increased to 258 "C and the pressure to 17.6 kg cm ² in order to carry out the initial ring opening of the caprolactam and the prepolymerization reactions. After this heating period, which lasts about 6 to 7 hours, the pressure gradually falls within I ¹ α Hours of relaxation from 17.6 kg cm ² to atmospheric pressure (relaxation period). The polymer is then extruded at 278 ° C. as a continuous band, cooled with water and cut into flakes 3.2 mm in size. The flakes are washed with water for 4 hours with stirring in a kettle at 95 ° C. in order to remove residues of the monomer. This operation is repeated three more times: Finally, 6.3 " _{o of} caprolactam has been extracted. The polymer is dried in vacuo (635 mm Hg) until the moisture content is less than 0.3". The flakes are melted again, extruded, sieved through a sieve with decreasing mesh sizes (0.6 to 0.074 mm) and pressed into tablets, which are then dried in vacuo to a moisture content of less than 0.03 ".

The specific electrical resistance of this Polymerisa! cast foils varies between 10 and 60 ohm cm.

Spinning and drawing

The polymers for the shell and the core are in a combined spinning and stretching machine at a winding speed of 1372 m / min (calculated from the speed of the winding roller in rpm) spun and drawn together.

The jacket polymer is at a throughput rate of 29.7 g / min (calculated from the Titer in the spun state and the winding speed) and the core polymer with a rate of increase of 6.7 g / min (calculated • from the titer in the spun state and the winding speed) fed, so that a concentric sheath-core thread is formed, which is 81 percent by weight (calculated from the throughput rates) from the jacket and at 19 percent by weight (calculated from the throughput speeds) consists of a core. When spinning, the temperatures Jtt of the billet melter as follows set:

The spinning block temperature is 29o ⁰ C. The yarn is drawn using a powered with steam Verstreckungsdüse and electrically heated, held at 180 ⁰ C rollers (16 wraps) to three times.

The drawn yarn is black and has the following properties:

Number of threads per bundle 1

Titer 19.02

Overall finish on the

Yarn. "" 1.83

Electrical resistance

of the core 1.3 · \ (f ohm / cm

Strength, g / den 2.5

Elongation at break, ",, 39.9

Module at 10 percent

Elongation, g the 13.6

Example 5
Sheath polymer

Polyethylene reed flakes with a relative Viscosity of 30.

Core polymerizai
Manufactured according to example 2.

Spin

The shell polymer and the core polymer graze according to Example 2 at one speed spun together by 787 m'min. The shell polymer is with a throughput speed of 36.3 g / min (calculated from the speed and the capacity of the pump) and the core polymer with a throughput rate of 1.38 g / min (calculated from the speed and the capacity of the pump) fed so that you get a concentric Composite thread is obtained, 96 percent by volume from the sheath and 4 percent by volume from the core exists, determined by enlarged cross-sectional receptacles.

When spinning, the temperature of the screw melting device for the jacket polymer set as follows:

Schncckcnschmel / -
contraption Temperature of
Mnnteipolymcrisats
C. Temperature of
Core polymer
C. Zone 1
Zone 2 286
284 114 (top)
184 (center)
242 (below)

The spinning block temperature is 292 ⁰ C.

A three-thread yarn of 60 denier is spun.

Stretch

The dreifädige 60-to-sheath Kcrngarn is at a speed of 415 m / min at a 97 ⁰ C hot heating shoe by 3.8 times stretched.

409 583/342

23

The drawn yarn has the following properties:

Titer, the 17.2

Thread count 3

Electrical resistance of the core,

Ohm / cm / thread 2.66 ■ JO ⁸

Strength, g / den 5.3

Elongation at break, "" 21.5

Initial modulus at 10 percent

Elongation, g / den 43.2

This sheath core yarn is used together with a commercially available 34-ply polyester yarn of 150 den textured in a false twist texturing machine. That jointly textured yarn (a strand of three-strand sheath core yarn of 17.2 denier with one strand of the 34-thread polyester yarn of 150 denier) is processed into a »Swiss pique« double-knitted fabric. This Knitted fabrics are dyed and finished using known methods. After washing 30 times, the knitted fabric becomes in an electrostatic tester (electrometer, Model E 525, from Presco Scientific Company) investigated and compared with a control knitted fabric made only from the same polyester yarn under the has been established under the same conditions.

103

Trial fabric ..
Control knit

Flektroslat Ladunsz au! "The knitted fabric. V after 0 seconds | after 120 seconds

400

2750

380
2550

This results in good electrostatic protection of the test product.

35

Example 6

A three-strand yarn of 60 denier is made from the polyhexamethylene adipamide used in Example 2 as the polymer for the sheath and the polycaprolactam used in Example 4 with a carbon black content of 28 " _o as the material for the core 4 percent by volume composed of the core, will be called at a 180 ⁰ C, the curved hot plate (61 cm) stretched to 3.0 times the yarn has then the following properties.:

Bundeltiter, the 20.2

Strength, g / den 3.18

Elongation at break, "" 49.1

Initial module, g / the 24.4

Electrical resistance of the core.

Ohm / cm / thread 1.77 I0 ⁹

Reflectivity, "" 32

Common puffing

The electrically conductive yarn is bulked according to Example 2 together with a 68-thread, basic stainable continuous hollow-thread carpet thread made of polyhexamethylene adipic acid amide with a titre of 1225 denier and made into carpets with flat knobs with a pile height of 6.35 mm and a weight per unit area of 0.475 kg / m ² processed as described in Example 2.

The reflectivity and static electricity of shine-colored carpets are compared with the corresponding properties of control carpets, which are not electrically conductive Thread included.

Electrostatic Loading capacity

of the carpet

kV)

1.5 to 2.4

8.6 to 9.8

Reflectivity
of the carpet

65

75

sample

Control ...

·) As in example 2.

The visual rating of the carpets is consistent with the measured reflectivity.

Example 7

Threads (4 strands with a tension of 60 den, 3 threads) with a polyamide sheath and a polyethylene core according to Example 2. the for use manufactured as staple fibers have the following properties:

Finishing on the yarn.
Weight percent core.
Weight per coat
Carbon content of
Kerns, "

.. 0.43
.. 3.5
..96.5

32.3

Reflectivity, " _o 39

Electrical resistance of the
Core bundle (12 threads) .. 2.0 · IO ^T Ohm cm

The spun yarn is drawn. putting 8 strands in an experimental drawing machine combined and with a winding speed of 210 m / min at a hot shoe temperature of 180 ° C to be stretched 3.0 times.

The drawn yarn has the following properties:

Bundeltiter, the 690

96 thread count

Firmness, g / den 4.72

Elongation at break. ", May 18

This electrically conductive yarn bundle is cut into pieces approximately 16.5 cm long and, during carding, 0.6, 2 or 5 "" is mixed in with commercially available carpet staple fibers made of polyhexamethylcnadipamide. 4 processed with 3.5 Z twists and 3.5 S twists each 2.54 cm. The yarns are heat set in the autoclave and then into carpets with cut pile (electric wool style) with a basis weight of 1.19 kg / m ² , a fabric density of 3.96 The carpets are washed and dyed in a conventional manner with a mixture of three commercially available yellow, red and blue acid dyes.

The dyed carpets give the following in the shuffle test at 20 "relative humidity and 21 ° C Values for the electrostatic charging rate:

Relationship of amUititjschen
Fibers? N basic fibers

0: 100
0.6: 99.4
2.0: 98.0
5.0: 95.0

As in example 2.

by virtue of the carpet
kV)

9.4

3.2
2.5
1.9

Example 8

This example illustrates an additional capacity for variation in the application of the invention. Every The sample has three threads per strand and the carbon black is the same as in Example 1.

Sample A is similar to the sample prepared according to Example 2 with the difference that the threads have a band-shaped cross section. The material for the The thread core contains 0.25 percent by weight of 1,3,5-trimethyl-2,4,6-tris- (3,5-di-tert-buty! -4-hydroxybenzyi) benzene as an oxidation retarder.

Sample B is similar to Sample A; the threads ^ have, however a three-leaf cross-section with a modification ratio from 2.50.

Samples C to H have round thread cross-sections.

Sample C consists of threads with a sheath made of polyhexamethylene adipamide, which contains 5% titanium dioxide contains, and a core made of 40% polypropylene, 20 "- ,, made of polyethylene, 10% a commercially available elastomeric copolymer from ethylene, propylene and a non-conjugated one Dien and 30% carbon black.

Sample D consists of threads with a sheath made of commercially available polypropylene and a core such as in sample A.

ίο sample E has the same jacket as sample D, while the core consists of a commercially available polycaprolactone resin with a carbon black content of 30%.

Sample F has a jacket made of polyhexamethylene adipamide with a titanium dioxide content of 5% and a core made of a commercially available polypropylene resin with a carbon black content of 25%.

Sample G has a jacket made of the same polypropylene as sample D and a pin core made of an im Commercially available polyethylene ether resin with a carbon black content of 26%.

Sample H is a non-exchanged control sample with a polyamide sheath as in sample A. and a core made of the same polyethylene resin. However without soot content.

The properties of the threads of these samples are shown in Table III.

Table III

sample Ver
stretching
relationship Tiler Idleness Test
strain At first
module Kernanieil
Volume percentage Reflection
capital
of the yarn More food
Resistance of the
Core yarn 10 * the g the g Jen (Cross-section) Ohm cm of thread A. 2.77 21.6 2.65 68.4 21.6 <10 28.5 1.2 B. 2.7 21.1 3.00 81.8 22.1 35 0.97 C. 3 110.6 2.19 62.8 14.2 3 49 3.54 D. 2.26 42.3 3.69 126 28.6 7.5 11 3.54 E. 2.0 104.4 1.72 150 14.7 7.4 12.5 0.15 F. 2.5 33.3 2.49 34.2 17.6 7.5 31.6 11.8 G 2.0 55.7 3.29 108 28.7 15th 11 0.12 H 2.70 19.1 3.87 34.5 23.6 4th > 10 ⁷

1 sheet of drawings

Claims (8)

23 Patent claims: .1, Antistatic synthetic two-component thread of the core-sheath type, consisting of an endless, electrically non-conductive sheath «Ms a synthetic thermoplastic thread-forming polymer that has a core made of a synthetic thermoplastic polymer surrounds and at least 50% of the thread cross-sectional area occupies, characterized in that the core in the thermoplastic synthetic Polymer contains dispersed, electrically conductive carbon black, is itself electrically conductive and below a DC potential of 2 kV, an electrical resistance of less than 0.4 10 "ohms / cm and the jacket is optionally molecularly oriented. 2. Thread according to claim 1, characterized in that the jacket _{occupies at least 80 ° o of} the thread cross-sectional area and the electrically conductive core contains more than 20 percent by weight of carbon black. 3. Thread according to claim 1 and 2, characterized in that the jacket is matted and the thread has a light reflectivity of more than 20 ° _o . 4. Thread according to claim 1 to 3, characterized in that the core is 15 to 50 percent by weight Contains soot. 5. Thread according to claim 1 to 4, characterized in that the polymer of the thread core has a lower Schnelzpu-kt and a lower glass transition temperature than the polymer of the thread jacket. 6. Process for the production of the synthetic antistatic two-component threads according to Claim 1 to 5 by composite spinning of two synthetic thermoplastic polymers with different electrical conductivity, with the polymer forming the thread for the thread sheath and the proportion of this polymer is at least 50 percent by volume, as well as collecting of the spun threads, characterized in that the material used for the electrically conductive thread core an electrically conductive carbon black in dispersion containing polymer and as Material used for the thread jacket and, if necessary, an electrically non-conductive polymer the threads then, optionally with heating, drawn so much that they have a firmness of at least 1.5 g / den. 7. The method according to claim 6, characterized in that that one has a mass with a specific electrical resistance of less for the core used as 200 ohm / cm. 8. Mixed continuous filament yarn or staple fiber mixture, characterized in that it consists of electrically non-conductive synthetic threads and less than 20 percent by weight of threads according to ß Claim 1 exists. 103