SK150994A3 - Fast-spun filaments based on polycaprolactam and process for producing them - Google Patents

Description

Technical field

The present invention relates to fibers with a relative viscosity (RV) of 2.0 to 3.0 (measured at a concentration of 1 g fiber per 100 ml by weight 96% sulfuric acid) based on polycaprolactam which are obtainable by:

(a) extrudes a melt consisting essentially of polycaprolactam through a spinneret, so that polycaprolactam filaments are formed;

(b) the filaments thus produced are cooled; and

(c) the cooled filaments are drawn off at a rate of at least 3600 + 1250. (3.0-RV) / m / min, wherein the polycaprolactam used is produced in the presence of at least one dicarboxylic acid selected from the group consisting of C 4 -C 10 alkanedicarboxylic acids , C5-C8 cycloalkanedicarboxylic acids, benzenedicarboxylic acids and naphthalenedicarboxylic acids, which may contain up to two sulfonic acid residues and whose carboxy groups are not adjacent to an amine of an N-alkyl-N, N-dialkanecarboxylic acid of 1 to 6 carbon atoms in the alkyl and 1 to 10 carbon atoms in each alkane moiety and 1,4-piperazinediacanecarboxylic acid having 1 to 10 carbon atoms in each alkane moiety.

The invention further relates to a process for the production of such fibers which can be used for the production of flat systems (Flächengebilden), as well as flat systems of these fibers.

BACKGROUND OF THE INVENTION

In the rapid spinning of polyamides, the fibers (Fäder) exiting the spinneret are generally drawn off at a speed above 3000 m / min from the spinner, whilst in conventional, conventional spinning, typically a maximum spinning speed of 1200 m / min is employed.

Compared to conventional spinning, rapid spinning provides a general advantage in higher productivity. In a few cases, especially polycaprolactam, the production step of saving can be saved under these circumstances. Furthermore, in the fast spinning. The advantage is that spinning and reeling are generally less dependent on the moisture content and the temperature of the surrounding air in the space than in conventional spinning. In addition, the shelf life of the wound fiber is generally improved until further processing over conventional spinning fibers. In addition, fast-spun fibers are generally particularly well suited for forming during elongation, warping at elongation and sizing at elongation.

The term " stretch-forming " refers to lengthening and shaping in a single working step in which a special fiber structure associated with the directional orientation of the macromolecules is formed during the forming. This generally results in higher elasticity, bulk coverage and thermal insulation as compared to smooth fibers. To improve further processing, such fibers can be further oiled or swirled (verwirbeln).

For the production of warp-knitted fabrics or fabrics, a large number of fibers must be fed in parallel to each other as a warp to a warp-knitting machine or to a loom. For this purpose, more than a hundred and sometimes up to several thousand fibers are wound on a spool. tree. In this process, the fibers are often expanded, oiled, paraffinized or sized to achieve a better marginal portion of the fibers and improve further processability. A larger number of such trees could be assembled in the next step to increase the number of fibers. The production of a partial warp tree can be combined with co-lengthening the entire warp of fibers (warp lengthening), sizing the fiber warp (sizing length), increasing the shear and providing better mechanical protection to the sizing agent wrap.

The stretching can also be associated with spinning, which is known per se, or can be integrated in it (on-line).

In European patent no. 201 189B discloses a process for the production of fast spinning polyamide filaments by extruding a molten polymer blend containing a low molecular weight additive such as water at a relative viscosity of from 2.0 to 3.0 (measured in 96% by weight sulfuric acid), the resulting filaments are cooled and the cooled filaments are drawn at a rate of 3,200 m / min. However, polycaprolactam fibers which are produced in the presence of a dicarboxylic acid chain regulator are not disclosed.

DE-A 40 19 780 describes a process for the production of polycaprolactam in the presence of dicarboxylic acids which serve as chain regulators. Fibers rapidly drawn at a pull-off speed of 4250 m / min, made from the caprolactam described therein (with a relative viscosity RV = 2.36), exhibit in fiber strength and ductility comparable to those of the prior art. ¹

The drawback of the elongated and recovered elongated or elongated fibers therefrom is that they generally have a lower tensile force value than the corresponding conventional spinning fibers up to the same elongation at the highest tensile force or fiber formation. Furthermore, the variation in the tensile force at fiber elongation achievable in measuring the tensile force independent of variation in length (tensile force-length change) of such fast-spun fibers is generally satisfactorily large, i.e. the curve is generally quite flat.

Compared to fast-spun polyamide 66 (polyhexamethylene amide adipic acid), fast-spun polycaprolactam fibers have the same elongation at the highest tensile strength after stretching and further have the disadvantage of low curl stability.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a fast spinning of polycaprolactam-based fibers which does not have the above-mentioned disadvantages. In particular, it is those fibers which have a higher change in tensile force (relative to the change in length), i.e. a steeper tensile force curve - a change in length, an improved maximum tensile force, and an improved curl stability when forming the fibers.

The fibers mentioned above have been found.

In addition, a process for the production of these fibers, their use in the manufacture of flat assemblies as well as flat assemblies of these fibers has been found.

According to the present invention, a melt is substantially spun which essentially comprises the polycaprolactam as defined above, wherein the cooled filaments are withdrawn at a rate of at least 600 3,600 I 1,250. (3.0-RV) / m / min, preferably at least 3 3 ^. 800 -i · 1250 (3.0-RV) / m / min. At a withdrawal rate higher than 3 3,600 + 1,250. (3.0-RV) / m / min, it is observed that the expected improvement in peak traction is not achieved. This is reflected in the fact that the higher the spinning speed is above / 3600 ϊ · 1 250. (3,0-RV) / m / min at a given value of relative viscosity RV, the higher the increase in the maximum tensile strength of the fiberized fibers . Commercially available polycaprolactam does not, according to the experience of the present inventor, have this effect either at all or only to a minor extent (see comparative examples).

The effect does not occur according to previous observations below the spinning speed / 3600 + 1250. (3.0-RV) / m / min at a given value of relative viscosity RV.

The upper limit of the spinning speed is generally not higher than 8,000 m / min and depends essentially on the melt viscosity of the spinning melt and the spinning equipment used.

The relative viscosity of the RV polycaprolactam to be spun is generally in the range of 2.0 to 3.0 (measured at a concentration of 1 g of caprolactam used per 100 ml of 96% sulfuric acid at 25 ° C, preferably in the range of 2.3 Polycaprolactam with a relative viscosity of more than 3.0 is generally highly viscous to allow it to be quickly spun and polycaprolactam with a relative viscosity of less than 2.0 does not generally form fiber-stable fibers.

The relative viscosity of the RV spinning fibers in the process of the present invention is in the range of from 2.0 to 3.0 (measured at a concentration of 1 g of polycaprolactam used per 100 ml of 96% sulfuric acid) at 25 ° C, preferably in the range of 2.3 to 2.9.

The process according to the invention uses a polycaprolactam which has been produced in the presence of at least one dicarboxylic acid which acts as a chain regulator. Such polycaprolactams are known, for example, from U.S. Pat. No. 3,386,976 and German DE-A 40 19 780. The production of the polycaprolactam according to the invention is preferably carried out in a one-step process as described in DE-A 40 19 780.

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The caprolactam is expediently polymerized in the presence of water as the initiator using a dicarboxylic acid together as a chain regulator at a temperature in the range of from 230 to 300 ° C, preferably from 240 to 290 ° C.

A suitable device for carrying out the polymerization is known to the person skilled in the art and is described, for example, in the German patents DE-AS 24 48 100 and 14 95 198 and in European patent no. 20 946B.

The water used as initiator is generally employed in an amount ranging from 0.1 to 5% by weight, in particular from 0.5 to 3.0% by weight, based on polycaprolactam.

The dicarboxylic acids used are preferably those which act as chain diffuser in the hydrolytic polymerization of caprolactam and do not decompose under polymerization and spinning conditions and also do not result in discoloration or other undesirable effects. Furthermore, dicarboxylic acids, which can, for example, cause the formation of a ring structure by chain bounding, are also not suitable. Examples of unsuitable dicarboxylic acids include succinic acid and phthalic acid, since ring closure can cause chain delimitation.

Suitable dicarboxylic acids are, for example, C 4 -C 10 alkanedicarboxylic acids such as adipic acid, pimelic acid, corkic acid, azelaic acid, sebacic acid, undecanedioic acid and dodecanedioic acid, preferably adipic acid, cycloalkane dicarboxylic acids of 5 to 8 carbon atoms such as cyclopentic acid 1,3-dicarboxylic acid and cyclohexane-1,4-dicarboxylic acid, preferably cyclohexane-1,4-dicarboxylic acid, benzenedicarboxylic acids and naphthalenedicarboxylic acids, which can carry up to two sulfonic acid residues, the corresponding alkali metal salts being also counted and their carboxy groups are not adjacent, such as terephthalic acid, isophthalic acid, naphthalene-2,6-dicarboxylic acid, and 5-sulfoisophthalic acid, preferably terephthalic acid, isophthalic acid and 5-sulfoisophthalic acid, and mixtures thereof of arginine N-alkyl-N, N-dialkanecarboxylic acids having 1 to 2 6 carbon atoms in the alkyl moiety and in each case having 4 to 10 carbon atoms in the alkane moiety, such as an amine of N-methyl-N, N-dicaproic acid and an amine of N-methyl-N, N-diacetic acid and 1,4-piperazinedic acid alkanecarboxylic acid in each case having 1 to 6 carbon atoms in the alkane moiety, such as an acid

1,4-piperazinediacetic acid, 1,4-piperazinediopropionic acid, 1,4-piperazinedipentanoic acid, 1,4-piperazinedipentanoic acid and 1,4-piperazinediindexanoic acid, preferably

1,4-piperazinediacetic acid and 1,4-piperazinedipropionic acid.

Fibers with dicarboxylic acids that carry tertiary amino groups can generally be easily dyed with anionic dyes. These may in some cases be desirable to achieve particularly intense color tones.

Fibers containing sulfonate groups are generally well colored with cationic dyes. In contrast, the ability of such fibers to react with the anionic dyes found in many foods and beverages decreases, reducing the susceptibility to soiling.

The dicarboxylic acids are expediently introduced into the upper part of the polymerization zone, ensuring complete mixing with the polymerizing melt. However, the dicarboxylic acids may also be added before or during the polymerization.

The dicarboxylic acids are generally added in an amount ranging from 0.05 to 0.6 mol%, in particular from 0.1 to 0.5 mol%, based on caprolactam.

In another embodiment, N, N-di (C ₁ -C ₆ -alkyl) amino- (C ₂ -C ₁₂ -alkyl) amine-type diamines can be used as chain regulator in addition to said di-8 carboxylic acids, if desired to improve dyeability compared to anionic dyes.

Examples which may be mentioned are 2-diethylamino-1-ethylamine, 6-dietylamino-1-hexylamine, 3-dimethylamino-1-propylamine and 3-diethylamino-1-propylamine, preferably 3-dimethylamino-1-propylamine and 3-diet .ylamino-l-propylamine.

The diamines of the N, N-di (C 1 -C 6 -alkyl) amino- (C ₂ -C ₁₂ -alkyl) amine type are preferably used in an amount ranging from 0.05 to 0.3 mol%, preferably from 0.1 to 0.3 mol% based on caprolactam. The use of less than 0.05 mole% does not generally lead to a substantial improvement in colorability, and above 0.3 mole% in general, the chain-bounding diamine will have a strong effect.

In another embodiment, in addition to the dicarboxylic acids mentioned above, primary monoamines may be used as chain regulator if it is desired to reduce the carboxyl group content and improve the melt stability of the product.

Suitable monoamines are C 4 -C 12 alkylamines and C ₆ -aryl-C ₁ -C ₄ -alkylamines, such as butylamine, pentylamine, hexylamine, heptylamine, octylamine, nonylamine, decylamine, undecylamine, dodecylamine, phenylmethylamine, phenymethylamine, phenymethylamine, phenymethylamine, phenymethylamine, phenymethylamine , phenylpropylamine and phenylbutylamine, preferably hexylamine, octylamine, decylamine and phenylethylamine.

The primary monoamines are preferably used in an amount ranging from 0.05 to 0.5 mol%, particularly preferably from 0.1 to 0.4 mol%, based on caprolactam.

In general, the polymerization can be carried out at a pressure in the range from 100 to 2000 kPa. A particularly preferred embodiment is that the polymerization is carried out continuously at the same pressure of from 100 to 190 kPa, preferably from 100 to 170 kPa, measured in the vapor phase of the polymerization zone, while maintaining a water content of from 0.1 to 0.5 %, in particular from 0.1 to 0.4 wt. in the melt. It will be appreciated that the excess amount of water above the range introduced above into the reaction zone is continuously distilled depending on the pressure used to maintain the above water content.

The polymerization time is generally 5 to 20 hours, preferably 8 to 12 hours, and is governed essentially by the desired properties of the product.

The polycaprolactam is conveniently removed from the polymerization zone at the lower end.

The content of chemically bound dicarboxylic acids (determined by hydrolysis of polycaprolactam and subsequent analysis) in the extracted and dried end product is generally in the range of from 5 to 60 mmol / kg, preferably from 10 to 50 mmol / kg. Generally, at values below 5 mmol / kg, it does not provide the desired improvement in the properties of the fibers obtained by rapid spinning. At values above 60 mmol / kg it is generally not possible to achieve the desired relative viscosity or the desired molecular weight for the production of the polymer.

If the end product contains additional chemically bonded diamines, their content is generally in the range from 5 to 30 mmol / kg, preferably from 10 to 30 mmol / kg, with the content of chemically bonded dicarboxylic acids generally being in the range of 10 to 50 mmol / kg, preferably from 15 to 50 mmol / kg.

The content of residual steam-extractable monomers and oligomers in the ready-to-spin polycaprolactam is selected in the range of 0 to 2% by weight. based on polycaprolactam.

The water content of the ready-to-spin polycaprolactam is generally in the range below 0.4 wt%, preferably from 0.02 to 0.15 wt%.

The fibers whirled according to the invention usually have an elongation at the highest tensile strength in the range of from 30 to 100%, preferably from 40 to 90%. By swirling, the elongation at the highest tractive force can further decrease as necessary.

The spinning polycaprolactam, as well as the fibers derived therefrom, may contain conventional additives and processing aids. Their proportion is usually up to 5% by weight, preferably up to 3% by weight. based on the total weight of polycaprolactam.

Conventional additives are, for example, stabilizers and oxidation retardants, anti-thermal decomposition agents, anti-ultraviolet decomposition agents, dyes, pigments, matting agents and antistatic agents.

For example, oxidation retardants and heat counteracting agents are sterically hindered phenols, hydroquinones, phosphites and derivatives of such compounds as well as substituted representatives of this group and mixtures of such compounds as well as copper compounds such as copper iodide and copper acetate.

Examples of stabilizers against ultraviolet radiation are substituted resorcinols, salicillates, benzotriazoles and benzophenones, which can generally be used in amounts up to 1% by weight. and divalent manganese compounds J are also suitable for this purpose

Suitable dyes are organic pigments and the usual spinning dyes such as complex chromium and copper compounds, inorganic pigments such as titanium dioxide and cadmium sulfide, iron oxides and carbon black for dyeing.

Conventional compounds such as polyalkylene oxides and derivatives thereof may be used as antistatic agents.

The addition of the additives can be carried out at any stage of the fiber production according to the invention, but the additives are expediently added before the stabilizers are added, in order to ensure protection from the outset. Accordingly, stabilizers are generally added during the polymerization process, as long as the process does not interfere with the addition.

The fibers of the present invention may be elongated, coextruded, coextruded, coextruded, coextruded, and formed in a manner known per se, as desired.

DÍženie tzv. the smooth yarn is carried out in one and the same fast spinning step (so-called fully draw yarn FDY or fully oriented yarn) or in separate work steps. Simultaneous stretching, sizing with simultaneous elongation and shaping during elongation are generally carried out in a working step separate from rapid spinning.

The fiber fibers of the present invention can be further processed into fibers (Faser) in a manner known per se. The flat assemblies can be produced, for example, by weaving, knitting on knitwear or knitting.

The quick-spinning fibers of the present invention have the advantage over the fibers obtained according to the prior art in that they have an improved tensile force, a steeper tensile force curve - a change in length, as well as a curl stability. The fibers according to the present invention further have a small number of elongation defects according to the prior art, as compared to the hitherto known fast-spun polycaprolactam fibers.

12 '

Further observation has shown that the polycaprolactam used according to the invention is characterized by reduced melt elasticity and a particular crystal morphology develops in the formation of the fiber. The improved properties of the fibers of the present invention are believed to be associated with the particular elastic melt behavior of the polymer and the particular fiber morphology.

DETAILED DESCRIPTION OF THE INVENTION

Examples

For the production of polycaprolactam, a VK tube with a mechanically stirred first reaction zone according to European Patent No. 20,946A is used. The VK tube has a filling volume of 340 liters and is heated with oil as the heat carrier.

The relative viscosity of RV of polycaprolactam or fiber is determined at a concentration of 1 g per 100 ml. 96% sulfuric acid at 25 º C.

The residual moisture content is determined by the method of determining the vapor pressure on an Ackermann instrument.

The content of chemically bound dicarboxylic acids and chemically bound diamine is calculated from the amount added. The content can also be determined by hydrolysis of polycaprolactam in dilute mineral acid and subsequent analysis of the mixture thus obtained.

To characterize the melt elasticity of polycaprolactam, the elasticity J _e at the elasticity determined by the oscillatory shear of the dicarboxylic acid controlled test samples of the present invention relates to the flexibility of J _{e Ref of} standard propionic acid products of the same viscosity.

The measurement is performed with a RDS2 rheometry dynamic spectrometer (Rheometrics) using a plate-to-plate arrangement (25 mm radius, 1 mm apart) at a temperature of 1350 ° C, with a shear amplitude of 0.3. The accumulation moiety G 'and the loss module G for a circular frequency from 0.3 to 100 rad / s are measured. On the measured curve, a circular frequency is indicated, for which the loss modulus shows a value of G corresponding to 10 ³ Pa. From the loss module G 'corresponding to this, the flexibility according to equation 1 is calculated.

J _e = G / (g) ² = G '/ 10 ⁶ Pa ² (equation 1)

Analogously, the flexibility of the reference set I _t is the product of the regulated propionic the same viscosity. · Finally, calculated by the relative number of R Measuring the ratio of the elasticity of the melt 2 by the equation

R - J _e / J _{e Ref} (equation 2)

This value represents a rheological characteristic number which makes it possible to detect a difference in very high dissolution melt elasticity (Auflósung).

The elongation at the highest tensile force is determined in a Uster-Tensorapid I measuring device with a clamping length of 200 mm for pre-oriented fibers (POY) and 500 mm for shaped fibers. The test time until fiber breakage is in the range of 20 ± 2 seconds. The tensioning force for pre-oriented fibers is 0.025 cN / dtex, for elongated fibers 0.05 cN / dtex and for shaped fibers 0.2 cN / dtex.

The maximum tensile force R _H at fine tensioning shall be calculated according to equation 3 ^r H '/ ^Tt v (equation 3) in which:

R _h means the highest tractive force in cN a

Tt _v means the initial (default) fineness in dtex.

The highest tensile force used shall be the highest value found in the elongation measurement at the highest tensile force.

The elongation at maximum tensile force ^E H shall be determined as the ratio of change in length / µl when the maximum tensile force is reached to the initial length l _{y of the} test sample and determined according to equation 4

Eg = / \ 1. 100% / l _v (equation 4), whereby the variation in length / µl is calculated from the difference in length of the test specimen at maximum pulling force, iH and initial length l _v In parallel to these determinations, plot the maximum pulling force versus change in length.

Warping errors are determined on a Lindly Standard Yarn Inspector Šerieš 1900 at a warp speed of 600 m / min.

The curl of the shaped fiber is determined according to DIN 53 840.

Directional curling of the shaped fiber is determined according to DIN 53 840.

The curl resistance of the shaped fiber is determined according to DIN 53 840.

In some selected examples, the spinning fiber morphology is characterized by low angle X-ray scattering (RKWS). Measurement of low angle X-ray scattering (RKWS) is performed in a Kiessig chamber at a pre-formed vacuum. The shades in the collimator tube have a diameter of 0.4 or 0.3 mm, the distance A between the fiber sample and the X-ray film (Agfa-Gevaert, Osray M3) is 400 mm. The source of radiation is a copper tube operated at a voltage of 37 kV and a current of 36 mA, the selection line of which (lambda wavelength = 0.15418 nm) is used for measurement.

To test the low-angle X-ray scattering, pre-oriented fibers are wound onto the frame, paying attention to the exact parallel position of the individual fibers. The fiber bundles with a thickness of 0.7 to 1 mm are perpendicular to the X-ray beam, the fiber axes being arranged vertically. The irradiation time is from 20 to 40 hours.

Meridian reflection of low-angle X-ray scattering of the crystal amorphous superstructure of the pre-oriented fibers is evaluated using a photometer (Microdensitomer 3CS, from Joyce Loebl).

The meridian reflection is determined on parallels to the film equator running meridial maxima using a gray wedge wedge of D = 0.95. The half-width of the resulting photometric curve is a measure of the thickness / _{F of the} crystal fibrils perpendicular to the filament axis. The lateral thickness of the crystal / \ _F, the closer the equations / \ _F ~ lambda (nm) / B (rad) (Equation 5) where lambda is a wavelength of X-rays, and

B (rad) is half the width of the photometric curve, measured in an arc

The value of B (rad) shall be obtained from half the width measured in millimeters of B (rad) by the equation

B (rad) = B (mm) / Λ. F (equation 6)

In formula A, the distance between the fiber test sample and the X-ray film and F is the photometer transmission factor. With the values A = 400 mm and F = 5 substituted to equation 5, the equation 7 / ρ - [lambda (nm) / B (mm)] is obtained. 2.10 ³ (equation 7)

For spinning, polycaprolactam is melted in a 3E-24S extruder (Barmag, 38 mm diameter, D / L ratio = 24) and extruded through nozzles (number of holes 12, hole diameter 0.20 mm, capillary length 0.40 mm) . The resulting fibers are first passed through an exhaust shaft (1600 mm high, 0.4 m / s lateral air blowing, 22 ° C and 65% relative humidity) and finally through a drop shaft (2000 mm high), drawn to AMS-Inventa controlled spinning station via 2 Duos galets with a diameter of 150 mm and winds on a SW 46 1S-900 reel winding device, obtained from Barmag.

The distance of the nozzle from the oil element is 1300 mm.

Mining is carried out cold at 740 m / min on a Rieter J5 / 10a extension.

The forming is performed on a machine designed for this purpose by FK6L-10 from Barmag at a speed of 600 or 800 m / min.

A. A method for producing polycaprolactam

Example 1

Molten caprolactam containing 0.5 wt. % water and 0.53 wt. The terephthalic acid as chain regulator is fed continuously and with stirring into the VK tube at normal pressure in the first reaction zone. The throughput is 25 kg / h. At the same time, a mixture of 70 wt. % polycaprolactam (relative viscosity = 1.9) and 30 wt. titanium dioxide (anatase modification) at 225 g / h to the first polymerization zone. The temperature in the first polymerization zone is 252 C. The polymerization heat released in the other reaction zones is removed by appropriate cooling using the internal heat exchangers. The temperature in the last reaction zone is 265 ° C.

After extraction with boiling water and subsequent drying, the product has a relative viscosity of 2.39, a (chemically bound) terephthalic acid content of 36 mmol / kg, a residual moisture content of 0.046% by weight. and a titanium dioxide content of 0.3 wt. The elastic flexibility J _e is 8.3 x ^{10 -6} Pa ^-1 and the relative specific number R corresponds to 0.78.

Example 2

Caprolactam is polymerized with 0.80 wt. The terephthalic acid as chain regulator is analogous to Example 1. The throughput is 30 kg / h and the metering of the titanium dioxide mixture corresponds to 270 g / h. The other test conditions were maintained as in Example 1.

The product has a relative viscosity of 2.32 and a (chemically bound) terephthalic acid content of 54 mmol / kg. The elastic flexibility J is 5.1.10 Pa and has a specific R number of 0.48. The residual moisture content is 0.016% by weight. and a titanium dioxide content of 0.3 wt.

Example 3

Caprolactam with a water content of 0.7 wt. % is polymerized with 0.21 wt. of terephthalic acid as a chain regulator at an excess pressure of 30 kPa in analogy to Example 1. The throughput is 34 kg / h. The temperature of the first reaction zone is adjusted to 240 C. No titanium dioxide is added.

The product has a relative viscosity of 2.71 and a (chemically bound) terephthalic acid content of 14 mmol / kg. The residual moisture content 0.019 wt.

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Example 4

Caprolactam with a water content of 0.6 wt. % is polymerized with 0.29 wt. terephthalic acid as chain regulator as in Example 3. The temperature in the first reaction zone was adjusted to 245 ° C. The remaining experimental conditions are maintained as in the example

3. No titanium dioxide is added.

The product has a relative viscosity of 2.71 and a (chemically bound) terephthalic acid content of 19 mmol / kg. Residual moisture content 0.021 wt.

Example 5a

Caprolactam with a water content of 0.6 wt. % is polymerized with 0.37 wt. terephthalic acid as a chain regulator analogous to Example 3. The temperature of the first reaction zone is adjusted to 251 C. C. The remaining experimental conditions were maintained as in Example 3. No titanium dioxide was added.

The product has a relative viscosity of 2.67, a (chemically bound) terephthalic acid content of 25 mmol / kg. Residual moisture content of 0.091 wt.

Example 5b

Caprolactam with a water content of 0.5% by weight. % is polymerized with 0.26 wt. adipic acid as a chain regulator analogously to Example 3. The throughput is 35 kg / h. The temperature of the first reaction zone is adjusted to 250 C. The remaining test conditions are maintained as in Example 3. No titanium dioxide is added.

The product has a relative viscosity of 2.67 and a (chemically bound) adipic acid content of 20 mmol / kg. The residual moisture content is 0.018% by weight.

I

Example 5c

Caprolactam is polymerized with 0.5 wt. % lithium salt of 5-sulfoisophthalic acid as chain regulator and 0.18 wt. titanium dioxide. After extraction with boiling water followed by drying, the product has a relative viscosity of 2.55 and a titanium dioxide content of 0.20% by weight. and a moisture content of 0.031 wt.

B. Rapid spinning of polycaprolactam

Example 6

The polycaprolactam produced in Example 1 is spun at a melt temperature of 265 ° C

(a) at a speed of 4 500 m / min; and

(b) at a speed of 5 500 m / min.

The relative viscosity of the fiber is 2.48. The titre after spinning is a) dtex 50 12 and b) dtex 41 12 12.

The fibers obtained at a spinning speed of 4,500 m / min and following elongation have a dtex titer of 44 f12.

The results are presented in Table 1.

Comparative Example 1

The run of Example 6 was repeated with commercial polycaprolactam (chain regulator: propionic acid, content in product = 40 mmol / kg, RV = 2.37, titanium dioxide content of 0.3 wt.%, Elastic flexibility 11,5.10 ^{- 6} Pa ^-1 , residual moisture content = 0.044% by weight) under otherwise identical conditions.

The results are presented in Table 1.

Example 7

The polycaprolactam produced in Example 2 is spun at a melt temperature of 265 ° C and a) at a speed of 5,500 m / min; and

(b) at a speed of 6 000 m / min.

The relative viscosity of the fiber is 2.31. The titre after spinning is a) dtex 42 f12 and b) dtex 43 f12.

The results are presented in Table 2.

Comparative Example 2

The experiment of Example 7 was repeated with the same commercially available polycaprolactam from Comparative Example 1 under otherwise identical conditions.

The results are presented in Table 2.

Example 8

The polycaprolactam produced in Example 3 is spun at a melt temperature of 275 ° C and a) at a speed of 4500 m / min;

(b) at a speed of 5 500 m / min; and

(c) at a speed of 6 000 m / min.

The relative viscosity of the fiber is 2.79. Titer after spinning poses

at (a) dtex 54 f12; at (b) dtex 51 f12 a at (c) dtex 52 f. 12. titer after stretching, the dtex is 45 f 12 at the spinning speed

500 m / min.

The results are presented in Table 3.

Comparative Example 3

The experiment of Example 8 was repeated with commercially available polycaprolactam (chain regulator: propionic acid, product content = 20 mmol / kg, relative viscosity ~ 2.68, elastic flexibility; 10.0.10 ^-6 Pa ^-1 , residual moisture content - 0.012 % by weight) under otherwise identical conditions.

The results are presented in Table 3.

Example 9

The polycaprolactam produced in Example 4 is spun at a melt temperature of 275 ° C and a speed of 4,500 m / min. The relative viscosity of the fiber is 2.83. The titer after spinning is dtex 54 f 12. Finally, the forming is carried out on a corresponding FK6L-10 (from Barmag) at a speed of 600 m / min and a heating temperature of 180 ° C with a D: Y ratio of 2.33 per HE- yarn (disc combination and arrangement: Ceratex fully ceramic discs in 1-5-1 configuration).

The results are presented in Table 4.

Comparative Example 4

The experiment of Example 9 was repeated with the commercially available polycaprolactam of Comparative Example 3 (residual moisture content 0.017 wt%) under otherwise identical conditions.

The results are presented in Table 4.

Example 10

The polycaprolactam produced in Example 5a is spun at a melt temperature of 275 ° C and a speed of 5,500 m / min. The relative viscosity of the fiber is 2.69. The titre after spinning is dtex 54 f12.

The results are presented in Table 4.

s

Comparative Example 5

The experiment of Example 10 was repeated with a commercially available polycaprolactam (chain regulator: propionic acid, product content = 20 mmol / kg, relative viscosity = 2.66, elastic flexibility = 10.0.10 ^-6 Pa ^-1 , residual moisture content = 0.098% %) under otherwise identical conditions.

The results are presented in Table 5.

Example 11

Polycaprolactam produced similar to Example 5a (with a terephthalic acid content of 0.37% by weight as a chain regulator, a relative viscosity = 2.67, a chemically bound terephthalic acid content of the final product = 25 mmol / kg and a residual moisture content of 0. 02% by weight), is spun at a melt temperature of 275 ° C and a speed of 4,500 m / min. The relative viscosity of the fiber is 2.78. The titer after spinning is dtex 54 f 12. Finally, the shaping is performed on the respective FK6L-10 machine (from Barmag) at a speed of 800 m / min and a heating temperature of 180 ° C, with a disc combination of Ceratex 1-5-1 and a ratio of D: Y corresponding to 2.2.

The results are presented in Table 6.

Comparative Example 6

The experiment of Example 11 was repeated with commercially available polycaprolactam (chain regulator: propionic acid, product content = 20 mmol / kg, relative viscosity = 2.68, residual moisture content = 0.017 wt%) under otherwise identical conditions.

The results are presented in Table 6.

Comparative Example 7 (An analogous embodiment to German DE-A 40 19 780.)

Polycaprolactam produced analogously to Example 4 of German patent DE-A 40 19 780, with a relative viscosity of 2.36, a titanium dioxide content corresponding to 0.03% by weight. and a residual moisture content corresponding to 0.04% by weight is melted in an extruder (Barmag 3E, 30 mm diameter 3-zone helix, with a low temperature mixing portion (LTM) and a por 2323 D / L = 24) at a temperature of 269 ° C and extruded through nozzles (13 holes, hole diameter 0.20 mm, capillary length 0.40 mm). Finally, the fibers are cooled in a blow chamber (1,500 mm long, transverse blowing) with air heated to 24 ° C and a relative humidity of 40% and then fed to a drop shaft of 2,200 mm length for winding on a reel.

The winding is carried out without the use of ballet swivel heads SW46 SSD from Barmag at a speed of 4250 m / min. The titre after spinning corresponds to dtex f 13.

The distance of the nozzle from the oil element is 1300 mm.

Mining is carried out on an appropriate yarn winding machine J5 / 10a from Rieter at a speed of 605 m / min to a titer after length of 44 f 13.

The results are presented in Table 7.

Comparative Example 8

The experiment of Comparative Example 7 is repeated with a commercially available polycaprolactam (chain regulator: propionic acid, product content = 40 mmol / kg, relative viscosity = 2.36, titanium dioxide content = 0.03 wt%, residual moisture content = 0 %, 04% by weight) under otherwise identical conditions.

Example 12

The polycaprolactam produced in Example 5b is spun at a melt temperature of 275 ° C and a) at a speed of 4,500 m / min;

(b) at a speed of 5 500 m / min; and

(c) at a speed of 6 000 m / min.

The relative viscosity of the fiber is 2.78. The titre after spinning is a) dtex 53 f 12, b) dtex 53 f 12 and c) dtex 54 f 12.

The fibers obtained at a spinning speed of 4,500 m / min and an attached elongation have a dtex titer of 44 f12.

The results are presented in Table 8.

Example 13

The polycaprolactam produced in Example 5c is spun at a melt temperature of 275 ° C and a) at a speed of 4500 m / min;

(b) at a speed of 5 500 m / min; and

(c) at a speed of 6 000 m / min.

The relative viscosity of the fiber is 2.57. The titre after spinning is a) dtex 54 f12, b) dtex 54 f12 and c) dtex 55 f12.

The fibers obtained at a spinning speed of 4,500 m / min and an attached elongation have a dtex titer of 44 f12.

The results are presented in Table 8.

Comparative example 9

The experiments of Examples 12 and 13 were repeated with commercially available polycaprolactam (chain regulator: propionic acid, product content = 20 mmol / kg, relative viscosity = 2.72, residual moisture content = 0.033 wt%) under otherwise identical conditions.

The results are presented in Table 8.

Table 1

Example 6 and Comparative Example 1

Towing speed m / min

POY (pre-oriented thread):

highest tensile force at fine tension cN / dtex elongation at highest tensile force%

Example 6

a) b)

Comparative Example 1

a) b)

500

500

500

500

4.5

4.6

4.3

4.2

53

54

FIBER FIBER:

highest tensile force at fine tension cN / dtex 4.8

4.6 elongation at maximum tractive force% 38

Overheating errors / 100 kg 0.3

Warp errors / 100 km 0.02

1.0

0.03

Example 6 shows that the highest tensile force in fine tensioning of the fibers is higher and in further processing results in a small number of errors as in Comparative Example 1

Table 2

Example 7 and Comparative Example 2

Example 7

a) b)

Comparative Example 2

a) b)

Towing speed m / min 5,500 6,000 5,500 6,000

POY (pre-oriented thread):

highest tensile force at fine tension cN / dtex elongation at highest tensile force% lateral crystal length nm

4.8 4.8 4.2 4.4

51 54 50

4.7 5.9 8.0 9.4

In these examples, the ultimate tensile strength at fine fiber tension (POY) is 9-14% higher than that of the prior art fibers.

Table 3

Example 8 and Comparative Example 3

Example 8

a) b) c)

Towing speed m / min

500 5 500 6 000

POY (pre-oriented fiber): highest tensile cN / dtex at fine tension

4.19 4.39

4.43 elongation at highest tensile force% lateral crystal thickness i nm 9.1

FIBER FIBER:

highest tensile force cN / dtex 4.73 at fine tension elongation at highest tensile force% 39

Table 3

Comparative Example 3 a) b) c) draw rate m / min

POY (pre-oriented thread):

highest tensile force at fine tension cN / dtex elongation at highest tensile force% lateral thickness of crystals nm

FIBER FIBER:

highest tensile force at fine tension cN / dtex elongation at highest tensile force%

500 5 500 6 000

3.72 3.81 3.75

66 59

10.5

4,38 4,6

These examples show that the ultimate pulling force (POY) of the present invention is also at a relatively low dicarboxylic acid content in the pre-oriented fiber 3 to 18% higher than in the comparative material and that at a draw speed of 6000 m / min there is a further increase in value.

Table 4

Example 9 and Comparative Example 4

Example 9

Comparative Example 4

POY (pre-oriented thread):

highest tensile force at fine tension cN / dtex 4.45 3.79 elongation at highest tensile force% 70

Fiber shaped at elongation: elongation ratio 1: 1.25 titer dtex 45 f 12 highest tractive force with gentle stretching cN / dtex 4.8

1: 1.31 43 f 12

4.4

drag at highest pulling force % 29 curvy E% 59 directional curling K% 43 curl stability B% 84

In this case, the highest tensile strength in the fine fiber tensioning (POY) of the present invention is 19% higher and in the yarn shaped at elongation 9% higher than in the comparative material. The curl stability of the fibers made of the polycaprolactam of the present invention is substantially increased (9%).

Table 5

Example 10 and Comparative Example 5 _x

Example 10 Comparative Example 5

POY (pre-oriented thread):

highest tensile force at fine tension cN / dtex

4.9

4.5 elongation at highest tractive effort% 53.9

55.5

The example illustrates the excellent highest tensile strength in the fine tensioning of the fibers of the present invention as compared to the prior art fibers. As can be seen from the example, an extraordinary combination of high strength and lower elongation at the highest tensile force, which can still be reduced by swirling, is unusual for the pre-oriented fiber. It shows excellent capability of the fibers according to the invention for further direct use, i. without additional gravity, as a pre-oriented fiber ready for use as a yarn.

Table 6

Example 11 and Comparative Example 6

Example 11 Comparative Example 6

POY (pre-oriented fiber): highest tractive force

with gentle tension cN / dtex 4.27 3.79 T dragging at high pulling force % 66 78 * lateral thickness nm 7.7 10.5 Fiber shaped on debt: ratio 1: 1.25 1: 1.31 titer j dtex 45 f 12 43 f 12 highest towing strength with gentle tension cN / dtex 4.9 4.36 dragging at high pulling force % 30 29 curvy E% 57 58 directional curvature K% 40 39

curl stability B%

In this example, the highest tensile strength of the fine tension of the fibers of the present invention is 12% higher in the yarn formed by elongation than in the comparative material. The curl stability is increased by 9% and demonstrates the suitability of the fibers of the invention also for the high forming speed under stretching.

Table 7

Comparative Examples 7 and 8

Comparative Comparative Example 7 Example 8

POY (pre-oriented thread):

highest tensile force at fine tension cN / dtex 4.4327 elongation at highest tensile force% 68

Tensioned fiber: highest tensile force at fine tension cN / dtex 4.95 elongation at highest tensile force% 35 elongation error / 100 kg 1.1 warping error / 100 km 0.31

4.98

0.17

These comparative examples show that at a pull-off speed of 4,250 m / min and a relative viscosity of 2.36 for dicarboxylic acid-regulated products (comparative example).

7) the highest tensile force is only 2.8% better when finely tensioning pre-oriented fibers than with a monocarboxylic compound-controlled product. This value is still within the precision of the assay. In the case of elongated fibers, no improvement can be discerned compared to the prior art product (Comparative Example 8).

Table 8

Examples 12 and 13 and Comparative Example 9

Example 12

a) b) c) Towing speed m / min 4 500. 5 500 6 000 POY (pre - oriented highest tractive force Fiber) cN / dtex 4.6 4.6 4.7

when gently tensioned stretch at highest

pulling force about, *about 70 61 54 FIBER FIBER: highest tensile force with gentle tension cN / dtex 5.3 drag on top ššej pulling force % 39

Example 13 a) b) c) Towing speed m / min 4,500 5,500 6,000 POY (pre - oriented highest tractive force Fiber) cN / dtex 4.6 4.8 4.8

at gentle tension, elongation at maximum tractive force% 68 59 54

FIBER FIBER:

highest tensile force cN / dtex 5.5 at fine tensioning elongation at highest tensile force% 36

Comparative example 9

a) b) C) Towing speed m / min 4,500 5,500 6 000 POY (pre - oriented Fiber) highest tractive force cN / dtex 4,1 4,2 4.1 with gentle stretching drag at highest pulling force % 77 65 60 FIBER FIBER: highest tractive force cN / dtex 4.9 with gentle stretching drag at highest pulling force % 40

In these examples, the ultimate tensile strength of the fine fiber tension in the case of the pre-oriented fiber and the elongated fiber is 8 to 17% higher than that of the prior art fibers.

Claims (7)

Fibers with a relative viscosity RV of 2.0 to 3.0 measured at a concentration of 1 g fiber per 100 ml by weight. 96% sulfuric acid, based on polycaprolactam, which are obtainable by the addition of (a) extrudes a melt consisting essentially of polycaprolactam through a spinneret so that polycaprolactam filaments are formed; (b) the filaments thus produced are cooled; and (c) the chilled filaments are withdrawn, characterized in that the chilled filaments are withdrawn at a rate of at least 600 3600 + 1250. (3,0 - RV) / m / min and provided that the polycaprolactam used is produced in the presence of at least one dicarboxylic acid selected from the group consisting of - C 4 -C 10 alkanedicarboxylic acids, - cycloalkane dicarboxylic acids of 5 to 8 carbon atoms, - benzenedicarboxylic acids and naphthalenedicarboxylic acids, which may contain up to two sulfonic acid residues and whose carboxyl groups are not adjacent, i an N-alkyl-N, N-diacocanecarboxylic acid amine having from 1 to 6 carbon atoms in the alkyl portion and in each case from 4 to 10 carbon atoms in the alkane portion; and - 1,4-piperazinedialocarboxylic acid having 1 to 10 carbon atoms in each alkane moiety Fibers according to claim 1, characterized in that the polycaprolactam is produced in the presence of at least one N, N-di (C 1 -C 6 -alkyl) amino- (C 1 -C 4 -alkyl) amine. Fibers according to claim 1 or 2, characterized in that they have an elongation at maximum 100% elongation. 4. A method for producing fibers with a relative viscosity RV of 2.0 to 3.0 measured at a concentration of 1 g fiber per 100 ml by weight. 96% sulfuric acid, based on polycaprolactam as claimed in claim 1, wherein the ^PART C (a) extrudes a melt consisting essentially of polycaprolactam through a spinneret, so that polycaprolactam filaments are formed; (b) the filaments thus produced are cooled; and (c) the chilled filaments are drawn off, characterized in that the chilled filaments are drawn off at a rate of at least / 3 600 + 1 250. (3,0-RV) / m / min and provided that the polycaprolactam used is produced in the presence of of at least one dicarboxylic acid _r . selected from the group consisting of n-alkanedicarboxylic acids having 4 to 10 carbon atoms, - cycloalkane dicarboxylic acids of 5 to 8 carbon atoms, - benzenedicarboxylic acids and naphthalenedicarboxylic acids, which may contain up to two sulphonic acid residues and whose carboxyl groups are not adjacent - an N-alkyl-N, N-dialkanecarboxylic acid amine having from 1 to 6 carbon atoms in the alkyl portion and in each case from 4 to 10 carbon atoms in the alkane portion, and - 1,4-piperazinedialocarboxylic acid having 1 to 10 carbon atoms in each alkane moiety A process for the production of polycaprolactam-based fibers according to claim 4, characterized in that a polycaprolactam which has been produced in the presence of at least one N, N-di (C 1 -C 6 -alkyl) amino- (C ₂ -C 11 _L 2 -) is ^used. (C 1 -C 4 alkyl) amine, C 4 -C 12 primary alkylamine, or C 6 -C 6 aralkylamine and C 1 -C 4 alkyl. Use of fibers according to claim 1, 2 or 3 or fibers produced according to claim 4 or 5 for producing fibers or flat assemblies. Fibers and flat assemblies obtainable using the fibers of claim 6.