EP1208255A1

EP1208255A1 - High-strength polyester threads and method for producing the same

Info

Publication number: EP1208255A1
Application number: EP00958291A
Authority: EP
Inventors: Joachim Cziollek; Werner Mrose; Dietmar Wandel; Helmut Schwind; Wolfgang Janas; Werner Ude
Original assignee: ZiAG Plant Engineering GmbH; Roehm GmbH Darmstadt
Current assignee: Roehm GmbH Darmstadt; LL Plant Engineering AG
Priority date: 1999-08-10
Filing date: 2000-07-25
Publication date: 2002-05-29
Anticipated expiration: 2020-07-25
Also published as: JP2003506588A; CN1166825C; WO2001011123A1; US6656583B1; EA200200173A1; ATE248939T1; EA004441B1; KR20020036840A; EP1208255B1; AU6986200A; DE19937729A1; CN1370247A; DE50003569D1

Abstract

High strength polyester fibers comprising from 0.1 to 2.0 by weight of an incompatible, thermoplastic amorphous, polymeric additive.

Description

High tenacity polyester thread and process for its manufacture

Description:

The invention relates to high-strength polyester thread with a tensile strength of> 70 cN / tex and a method for producing this thread.

High tensile thread made of polyethylene terephthalate and process for its

Manufacture has long been known (F. Fourne, Synthetic Fibers, Hanser Verlag Munich [1995] 584-586; US Pat. Nos. 3,758,658, 4,374,797 and 4,461,740).

These high-strength threads require special properties, above all a high tensile strength, a low elongation at break and a small number of thread defects. Technologically, these requirements are linked to the use of high draw ratios of at least 1: 5 in raw yarn production. However, higher drawing ratios have their limits if the thread is already damaged by the drawing and thread breaks occur. The higher the production speed, the lower this limit is. However, the technical and economic value of the spin-stretching process when using high production speeds can only be assessed positively if, at the same time, the textile thread quality is not deteriorated, but is even improved. The spinning take-off speed in commercial processes is limited to a maximum of 700 m / min, generally 500 to 600 m / min. The The winding speed is, depending on the stretching ratio, between 2500 m / min and below 3800 m / min.

It is also known from WO 99-07927A1 that the elongation at break of pre-spun polyester filaments (POY) spun at take-off speeds of at least 2500 m / min, preferably 3000 to 6000 m / min, by adding amorphous, thermoplastically processable copolymers based on styrene , Acrylic acid and / or maleic acid or their derivatives compared to the elongation at break of polyester filaments spun under the same conditions can be increased without addition. However, the process cannot be transferred to spinning threads produced at take-off speeds of less than 2500 rπ / min, since, in contrast to POY fibers, these are not very crystalline (<12%), low orientation (birefringence <25 ^• 10 ³ ) and high elongation at break (> 225%). Information on the production of high-strength yarns in the integrated spin-stretching process is not included.

EP 0 047 464 B relates to an undrawn polyester yarn, the addition of 0.2-10% by weight of a polymer of the type - {CH ₂ -CR, R ₂ ) - _n , such as poly (4-methyl-l -pentene) or polymethyl methacrylate, an improved productivity is obtained by increasing the elongation at break of the filament at speeds between 2500 - 8000 m / min. A fine and uniform dispersion of the additive polymer by mixing is necessary, the particle diameter having to be less than 1 μm in order to avoid the formation of fibers. Decisive for the effect is the interaction of three properties - the chemical additive structure, which hardly allows the additive molecules to stretch, the low mobility and the compatibility of polyester and additive.

EP 0 631 638 B describes fibers made predominantly of PET which contain 0.1-5% by weight of a 50-90% imidized polyethacrylate alkyl ester contains. The fibers obtained and subsequently finally drawn at speeds of 500-10,000 m / min are said to have a higher initial modulus. In the examples of industrial yarns, the influence on the module cannot be easily understood; in general, the strengths achieved are low, which is a considerable disadvantage for this product.

It is also known to the person skilled in the art that, under the same spinning and stretching conditions, the tensile strength can be influenced dramatically by changing the amount of relaxation. With the relaxation ratio, the thermal shrinkage of such high-strength thread is set in practice depending on the industrial application. The thermal shrinkage is reduced as the relaxation ratio increases, but so does the tensile strength and LÄSE 5, while the elongation at break increases.

The present invention has for its object to provide high-strength polyester thread with a tensile strength> 70 cN / tex and to provide a method for its production in which spinning take-off speeds and winding speeds can be used that are significantly higher than those of the prior art. In particular, with a relaxation ratio RR> 0.97 tensile strengths> 80 cN / tex, with a relaxation ratio 0.95 <RR <0.97 tensile strengths> 77 cN / tex and with a relaxation ratio RR <0.95 tensile strengths> 70 cN / tex can be achieved.

This object is achieved according to the invention by high-strength polyester thread and by a method for its production according to the claims.

Among polyester here are Po1y (C ₂ , "- alkylene) terephthalates, which up to 15 moles of other dicarboxylic acids and or diols, such as. B. isophthalic acid, adipic acid, diethylene glycol, polyethylene glycol, 1,4-cyclohexanedimethanol, or the other C ₂ _ ₄ -alkylene glycol 1e, may be understood. Preference is given to polyethylene terephthalate with an internal viscosity (IV) in the range from 0.8 to 1.4 dl / g, polypropylene terephthalate with an IV from 0.9 to 1.6 dl / g and polybutylene terephthalate with an IV from 0.9 to 1 , 8 dl / g. Usual additives, such as dyes, matting agents, stabilizers, antistatic agents, lubricants, branching agents, can be added to the polyester or the polyester additive mixture in amounts of 0 to 5.0% by weight without disadvantage.

According to the invention, a copolymer is added to the polyester in an amount of 0.1 to 2.0% by weight, the copolymer having to be amorphous and largely insoluble in the polyester matrix. The two polymers are essentially incompatible with one another and form two phases that can be distinguished microscopically. Furthermore, the copolymer must have a glass transition temperature (determined by DSC with 10 ° C./min heating rate) of 90 to 170 ° C. and must be processable thermoplastically.

The melt viscosity of the copolymer should be chosen so that the ratio of its melt viscosity extrapolated to the measuring time zero, measured at an oscillation rate of 2.4 Hz and a temperature which is equal to the melting temperature of the polyester plus 34.0 ° C (for Polyethylene terephthalate 290 ° C) relative to that of the polyester, measured under the same conditions, is between 1: 1 and 7: 1. That is, the melt viscosity of the copolymer is at least equal to or preferably higher than that of the polyester. Optimal efficiency is only achieved by selecting a specific viscosity ratio of additive and polyester. With such an optimized viscosity ratio, it is possible to reduce the amount of additive additive, which makes the process particularly economical. Surprisingly, the viscosity ratio determined according to the invention as ideal for the use of polymer mixtures for the production of high-strength yarns lies above the

Range which is indicated in the literature as being favorable for the mixing of two polymers. In contrast to the prior art, polymer mixtures with high molecular weight copolymers were excellently spinnable.

Due to the high flow activation energy of the additive polymers, the viscosity ratio increases drastically in the area of the thread formation after the polymer mixture has emerged from the spinneret. Here, the flow activation energy (E) is a measure of the rate of change of the zero viscosity as a function of the change in the measurement temperature, the zero viscosity being the viscosity extrapolated to the shear rate 0. (M. Pahl et al., Practical Rheology of Plastics and Elastomers, VDI-Verlag, Dusseldorf (1995), pages 256 ff.). By choosing a favorable viscosity ratio, a particularly narrow particle size distribution of the additive is achieved

Polyester matrix and by combining the viscosity ratio with a flow activation energy of significantly more than that of the polyester (PET about 60 kJ / ol), ie more than 80 kJ / ol, a fibular structure of the additive is obtained in the spinning thread. The glass transition temperature, which is high in comparison to polyester, ensures that this fibrous structure is quickly consolidated in the spinning thread. The The maximum particle sizes of the additive polymer are about 1000 nm immediately after emerging from the spinneret, while the mean particle size is 400 nm or less. After warping below the spinneret and stretching, fibers with an average diameter <80 nm are formed.

The ratio of the melt viscosity of the copolymer to that of the polyester under the above-mentioned conditions is preferably between 1.5: 1 and 5: 1. Under these conditions, the mean particle size of the additive polymer is 120-300 nm immediately after it emerges from the spinneret, and this results Fibπllen with an average diameter of about 40 πm.

The additive polymers to be added to the polyester according to the invention can, provided they have the properties mentioned above, have a different chemical composition. Three different types of copolymers are preferred, namely

1. A copolymer which contains the following monomer units:

Acrylic acid, methacrylic acid or CH _Z = CR - C00R ¹ , where R is an H atom or a CH ₃ group and R ^{1 is} a C ,. ₁₅ alkyl radical or a C _{5 12} cycloalkyl radical or a C _D. ₁₄ aryl radical,

B styrene or C ₁ . ₃ -alkyl-substituted styrenes,

the copolymer consisting of 60 to 98% by weight of A and 2 to 40% by weight of B, preferably of 83 to 98% by weight of A and 2 to 17% by weight of B, and particularly preferably of 90 to 98% by weight. -% A and 2 to 10 wt .-% B (sum = 100 wt .-%). 2. A copolymer which contains the following monomer units:

C = styrene or C ^ alkyl-substituted styrenes,

D one or more monomers of the formula I, II or III

R - C = C - R ₂ R - C - COOH R - C - C = 0

I I II II) o

0 = C _{χ /} C = 0 R ₂ - C - COOH R - C - C = 0 N

I (i) (ii) (in)

R ₃

where R ,, R ₂ and R _{3 are} each an H atom or a C ,. ₁₅ - alkyl radical or a C _5-12 cycloalkyl radical or a C ₅ . ₁₄ -

Aryl radical,

the copolymer consisting of 15 to 95% by weight of C and 5 to 85% by weight of D, preferably of 50 to 90% by weight of C and 10 to 50% by weight of D and particularly preferably of 70 to 85% by weight. -% C and 15 to 30 wt .-% D, the sum of C and D together making 100%.

3. A copolymer which contains the following monomer units:

E acrylic acid, methacrylic acid or CH ₂ = CR - COOR ¹ , where R is an H atom or a CH ₃ group and R 'is a C,. ₁₅ -Alkylrest or a C ₅ . Is _12- cycloal kylrest or a C ₅ _ ₁₄ aryl est,

F = styrene or C, _ ₃ -alkyl-substituted styrenes, G = one or more monomers of the formula I, II or III

R - C = C - R ₂ R - C - COOH R - C - C = 0

II II II) o 0 = C _{χ /} C = 0 R ₂ - C - COOH R - C - C = 0

N

I (I) (II) (HI)

R ₃

where R ,, R ₂ and R _{3 are} each an H atom or a C, _, ₅ -

Alkyl radical or a C ₅ . ₁₂ -cycloalkyl radical or a C ₅ . ₁₄ - aryl radical,

H = one or more ethylenically unsaturated monomers copolymerizable with E and / or with F and / or G from the group consisting of α-methyl styrene, vinyl acetate, acrylic acid esters, methacrylic acid esters which are different from E, vinyl chloride, vinylidene chloride, halogen-substituted styrenes , Vinyl esters, isopropenyl ethers and dienes, the

Copolymer of 30 to 99% by weight E, 0 to 50% by weight F,> 0 to 50% by weight G and 0 to 50% by weight H, preferably 45 to 97% by weight E, 0 to 30% by weight of F, 3 to 40% by weight of G and 0 to 30% by weight of H and particularly preferably from 60 to 94% by weight of E, 0 to 20% by weight of F, 6 to 30 % By weight of G and 0 to 20% by weight of H, the sum of E, F, G and H totaling 100%. Component H is an optional component. Although the advantages to be achieved according to the invention can already be achieved by copolymers which have components from groups E to G, the advantages to be achieved according to the invention also occur if further monomers from group H are involved in the construction of the copolymers to be used according to the invention.

Component H is preferably selected so that it has no adverse effect on the properties of the copolymer to be used according to the invention. Component H can u. a. can be used to modify the properties of the copolymer as desired, e.g., by increasing or improving the flow properties when the copolymer is heated to the melting temperature, or to reduce residual color in the copolymer, or by using a polyfunctional monomer to do so and to introduce some degree of crosslinking into the copolymer. In addition, H can also be chosen so that a copolymeπsation of components E to G is possible or supported in the first place, as in the case of MSA and MMA, which do not copolymeπsise per se, but copolymeπsieren easily when adding a third component such as styrene.

The monomers suitable for this purpose include vinyl esters, esters of acrylic acid, for example methyl and ethyl acrylate, esters of methacrylic acid which differ from methyl methacrylate, for example butyl methacrylate and ethylhexyl methacrylate, vinylchloride, vinylidene chloride, styrene, α-methyl styrene and the various halogen-substituted styrenes, vinyl and isopropenyl ether, dienes, such as 1,3-butadiene and divinylbenzene. The color reduction of the copolymer can, for example, particularly preferably by using an electron-rich monomer, such as a vinyl ether, vinyl acetate, styrene or α-methyl styrene can be achieved. Particularly preferred among the compounds of component H are aromatic vinyl monomers, such as styrene or α-methyl styrene.

The preparation of the copolymers to be used according to the invention is known per se. They can be prepared in bulk, solution, suspension or emulsion polymerization. Helpful hints can be found with regard to substance polymerization in Houben-Weyl, Volume E20, Part 2 (1987), page 1145ff. Information on solution polymerization can be found there on page 1149ff, while emulsion polymerization is described and explained there on page 1150ff.

In the context of the invention, particular preference is given to bead polymers whose particle size is in a particularly favorable range. The copolymers to be used according to the invention, for example by mixing into the melt of the fiber polymers, are preferably in the form of particles having an average diameter of 0.1 to 1.0 mm. However, larger or smaller pearls or granules can also be used, although smaller pearls place special demands on logistics, such as conveying and drying.

The imidized copolymer types 2 and 3 can be prepared from the monomers using a monomeric imide or by subsequent complete or, preferably, partial imidization of a copolymer containing the corresponding maleic acid derivative. These additive polymers are obtained, for example, by completely or preferably partially reacting the corresponding copolymer in the melt phase with ammonia or a primary alkyl or arylamine, for example amiine (Encyclopedia of Polymer Science and Engineering Vol 16 [1989], Wiley-Verlag, page 78). All of the copolymers according to the invention and, as far as given, their unidentified starting copolymers are commercially available or can be prepared by a process familiar to the person skilled in the art.

The amount of the copolymer to be added to the polyester is 0.1 to 2.0% by weight, with addition amounts of less than 1.5% usually being sufficient. The concentration of the polymeric additive in the range 0.1 to 2.0% by weight is preferably selected depending on the desired spin take-off speed (> 700-1500 m / min) so that the

The birefringence of the spinning thread is <3.5 ^• 10 ^"3. Such birefringence in the spinning thread allows drawing ratios of 1: 5 and ensures the desired high thread strengths, regardless of the spinning take-off speed of up to 1500 m / min at winding speeds also significantly above 3800 m / min.

In this case, the concentration of the additive is determined experimentally in preliminary tests under operating conditions, as follows:

The person skilled in the art knows for a certain polymer without additive according to the invention, under the specific spinning and drawing conditions at a spinning take-off speed v _0, the drawing behavior necessary to achieve high tensile strengths. He also knows the birefringence of the filament in this process or can determine it. If he now wants to run the process according to the invention at higher speeds, he only has to determine the concentration of additive with which the spinning thread has the same birefringence as the spinning thread at v ₀ without additive. For this purpose, the birefringence at the higher spinning speed is determined for about 4 different additive concentrations in the range 0.1% to 1.5% and from the graphic representation this connection determines the necessary concentration by interpolation.

The additive polymer (copolymer) is mixed with the matrix polymer by adding it as a solid to the matrix polymer chips in the

Extruder inlet with chip mixer or gravimetric metering or alternatively by melting the additive polymer, metering by means of a gear pump and feeding into the melt stream of the matrix polymer. So-called masterbatch technologies are also possible, the additive being present as a concentrate in polyester chips which are later added to the matrix polyester in the solid or molten state. The addition to a partial stream of the matrix polymer, which is then mixed into the main stream of the matrix polymer, is also practical.

A homogeneous distribution is then produced by mixing using a static mixer. Advantageously, a specific particle distribution is set by the specific choice of mixer and the duration of the mixing process, before the melt mixture is passed on through product distribution lines to the individual spinning stations and spinnerets. Mixers with a shear rate of 16 to 128 sec ^"1 have been retained. The product of the shear rate (sec ¹ ) and the 0.8th power of the residence time (in sec) should be at least 250, preferably 350 to 1250. Values above 2500 generally avoided in order to keep the pressure drop in the piping limited. The shear rate is defined by the shear rate in the empty tube (sec ^"1 ) times the mixer factor, the mixer factor being a characteristic parameter of the mixer type. For Sulzer SMX types, for example, this factor is about 7-8. The shear rate γ is calculated in the empty tube according to

10 ^yy

- ^r r sec ι i π δ R ³ 60 ^J

and the time according to (sec)

t _ V, = ^v _ ε δ 60

in which

F Required amount of polymer (g / min)

V ₂ = inner volume of the empty pipe (cm ³ )

R = empty tube radius (mm) ε = empty volume fraction 1 (for Sulzer-SMX types 0.84 to 0.88) δ = nominal density of the polymer mixture in the melt (approx. 1.2 g / cm ³ )

Both the mixing of the two polymers and the subsequent spinning of the poly mixture takes place at temperatures, depending on the matrix polymer, in the range from 220 to 320 ° C., preferably at (melting temperature of the matrix polymer + 34) ± 25 ° C. Temperatures of 265 to 315 ° C. are preferably set for PET.

The production of the high-strength thread from the polymer mixtures according to the invention by spinning at take-off speeds from> 700 m / min, preferably 750 to 1000 m / min, stretching with a stretching ratio of at least 1: 5, heat setting and winding at a corresponding speed of> 3800 m / min, is carried out using spinning devices known per se. Here, the filter package according to the known prior art

Filtereinπchtungen and / or loose filter media populated.

After the shear and filtration treatment, the molten polymer mixture is pressed through the holes in the nozzle plate in the nozzle package. In the subsequent cooling zone, the melt threads are cooled below their solidification temperature by means of cooling air, so that sticking or upsetting on the following thread guide member is avoided. The cooling air can be supplied from a climate system by transverse or radial blowing. After cooling, the spinning thread is subjected to spinning preparation, drawn off at a defined speed via godet systems, then drawn, heat-set and finally wound up.

It is typical of high-strength polyester threads that they are produced in large direct melt spinning systems in which the melt is distributed over long heated product lines to the individual spinning lines and within the lines to the individual spinning systems. Here, a spinning line represents a series of at least one row of spinning systems and a spinning system is the smallest spin unit with a spinning head which contains at least one spinneret package including spinneret plates.

In such systems, the melt is subject to a high thermal load with dwell times of up to 35 minutes. Due to the high thermal stability of the additive, the effectiveness of the polymer additive according to the invention does not lead to any noteworthy Limitations of its effect, so that a small amount of additive <2.0% and in many cases <1.5% is sufficient despite high thermal stress.

According to the invention, an improvement in drawability, characterized by an equally high draw ratio at a higher spinning take-off speed, is achieved. In particular, by a suitable choice of the additive concentration C, the spin draw-off speed at the spinneret can be set at least 200 m / min higher than when spinning polyester without additive additive.

The properties of the additive polymer and the mixing technique mean that the additive polymer forms spheroidal or elongated particles in the matrix polymer immediately after the polymer mixture has emerged from the spinneret. The best conditions were found when the mean particle size (arithmetic mean) d ₅₀ <400 nm and the proportion of particles> 1000 nm in a sample cross-section was less than 1%.

The influence of these particles by the spinning draft or the drawing could be verified analytically. New investigations of the thread by the TEM method (transmission electron microscopy) have shown that there is a fibular structure. The mean diameter of the fibers after stretching was estimated at approximately 40 nm and the length / diameter ratio of the fibers was estimated to be> 50. If these cases are not formed or are

Additive particles after leaving the spinneret are too large in diameter or if the size distribution is too uneven, which is the case if the viscosity ratio is insufficient, the effect is lost. Furthermore, a glass transition temperature of 90 to 170 ° C, and preferably a flow activation energy of the copolymers of at least 80 kJ / mol, that is, a higher flow activation energy than that of the polyester atπx is required for the effectiveness of the additives according to this invention. Under this condition, it is possible for the additives to solidify in front of the polyester matrix and to absorb a considerable proportion of the applied spinning tension.

The high-strength threads according to the invention have at least the same quality values as conventional threads without a polymeric additive.

The property values given in the examples below and in the text above were determined as follows:

Additi vfibπllen: The examination of the microtome thin sections of the thread was carried out by means of trans ission electron microscopy and subsequent image analysis, the diameter of the fibers being assessed and the length from the particle diameter determined in samples immediately after the spinneret being estimated.

The internal viscosity (I.V.) was determined on a solution of 0.5 g polyester in 100 ml of a mixture of phenol and 1,2-dichlorobenzene (3: 2 parts by weight) at 25 ° C.

To determine the melt viscosity (initial viscosity), the polymer was dried in vacuo to a water content of <1000 ppm (polyester <50 ppm). The granules were then introduced into the temperature-controlled measuring plate in a cone-plate rheometer, type UM100, Physica Messtechnik GmbH, Stuttgart / DE, while blanketing with nitrogen. The measuring cone (MK210) was melted after the Sample, ie after approx. 30 seconds, positioned on the measuring plate. The measurement was started after a further heating-up period of 60 seconds (measuring time = 0 seconds). The measurement temperature was 290 ° C for polyethylene terephthalate and additive polymers, which are added to polyethylene terephthalate, or was the same

Melting temperature of the affected polyester plus 34.0 ° C. The measuring temperature thus determined corresponds to the typical processing or spinning temperature of the respective polyester. The amount of sample was chosen so that the rheometer gap was completely filled. The measurement was carried out in oscillation with the frequency 2.4 Hz (corresponding to a shear rate of 15 sec ^"1 ) and a deformation amplitude of 0.3, and the amount of the complex viscosity was determined as a function of the measurement time. The initial viscosity was then determined by linear regression converted to zero measurement time.

To determine the glass transition temperature and the melting temperature of the polyester, the polyester sample was first melted at 310 ° C. for 1 minute and immediately quenched to room temperature. The glass transition temperature and the melting temperature were then determined by DSC measurement (differential scanning calorimetry) at a heating rate of 10 ° C./min. Pretreatment and measurement were carried out under a nitrogen blanket.

The birefringence of the fibers (Δη) was determined using

Polarizing microscope with tilt compensator and green filter (540 nm) determined using wedge cuts. The path difference between the ordinary and the extraordinary beam when linearly polarized light passed through the filament was measured. The birefringence is the quotient of the path difference and the Fila ent diameter. In the spinning stretching process, the spun thread was removed after the take-off godet.

The strength properties of the fibers were determined on threads to which a twist of 50 T / m was applied, on a test length of 250 mm with a take-off speed of 200 mm / min. The force, which corresponds to a strain of 5% in the force-strain diagram divided by the titer, is referred to as LASE-5.

The hot air shrink was made using the company's shrinkage tester

Test rites / USA at 160 ° C, a preload of 0.05 cN / dtex and a treatment time of 2 min.

Comparative Examples 1 and 2:

Polyethylene terephthalate chips with an intrinsic viscosity of 0.98 dl / g and a moisture content of 20 ppm were melted in a 7E extruder from Barmag, DE, at a temperature of 295 ° C. and at a pressure of 160 bar pressed a product line with installed static mixers and fed to a 2 x 15 cm ³ spinning pump. The polymer melt was subjected to a shear rate of 29 sec ^"1. The product of the shear rate and the 0.8th power of the residence time in seconds was 532. 0.4 mm nozzle hole diameter). The melt throughput per spinning package was 385 g / min at all settings. This corresponds to a titer of 1100 dtex at a winding speed of 3500 m / min. The nozzle pressure was 330 bar. The spun multifilament thread then went through the spinneret was a 330 mm long reheater (330 ° C), was then cooled in a cross-start system, applied to the spin preparation by means of a Breitschi itzöler and fed to an unheated pair of feed rollers. The speed of this pair of feed rollers is conventionally referred to as the spinning take-off speed. Only for sampling for the determination of the birefringence was the spinning thread already fed to a winding unit after this pair of feed rollers. To produce the high-strength thread, the thread was passed over 4 heated godet duos after the pair of inlet rollers and finally wound up. Stretching took place between the 1st and 3rd duo, heat-setting on the 3rd duo and relaxation between the 3rd duo and the winder (the relaxation ratio representing the ratio of the winding speed to the speed of the fixing duo).

The 4 heated duos had the following temperatures

Duo 1 95 ° C

Duo 2 120 ° C

Duo 3 240 ° C

Duo 4 150 ° C

The preload ratio between Duo 1 and the pair of infeed rollers was 1.02 in all cases. The part 1 relax ratio between Duo 4 and Duo 3 was 0.995 in all cases.

The other test parameters and the results are summarized in the table.

Examples 3 to 7

Execution and polyethylene terephthalate (PET) correspond to the comparative examples. However, was used to manufacture the polymer

Mixture according to the invention an additive by means of a metering device Type KCLKQX2 from K-Tron Soda, DE, dosed into the filler of the extruder. A copolymer of 90% by weight of methyl methacrylate and 10% by weight of styrene was chosen as additive, which had a glass transition point of 118.7 ° C. and a melt viscosity ratio, based on PET, of 2.8. The dosing quantity given in the table was set according to a gravimetric dosing quantity regulation.

The other test parameters and the results are summarized in the table. In all cases the mean diameter of the fibrils in the threads was below 80 nm.

Table:

Claims

claims

1. High-strength polyester threads with a tensile strength of> 70 cN / tex, characterized in that they are made of

α) a polyester which contains at least 85 mol% of poly (C _2-4 -alkylene) terephthalate,

ß) 0.1 to 2.0 wt .-% of an incompatible, thermoplastically processable, amorphous, polymeric additive, which a

Glass transition temperature in the range of 90 to 170 ° C, and

γ) 0 to 5.0% by weight of conventional additives,

exist, the sum of α), ß) and γ) equal to 100%, the ratio of the melt viscosity of the polymeric additive ß) to the melt viscosity of the polyester component α) is 1: 1 to 7: 1, and the polymeric additive ß) in the yarn is in the form of fibrils with an average diameter of <80 nm distributed in the polyester component α).

2. High-strength polyester threads according to claim 1, characterized in that the ratio of the melt viscosities is 1.5: 1 to 5: 1.

3. High-strength polyester threads, according to claims 1 or 2, characterized in that the polymeric additive β) is a copolymer which contains the following monomer units: Acid A = acrylic acid, methacrylic or CH ₂ = CR - COOR ', where R is an H atom or a CH ₃ group and R' yl radical is a C, _ ₁₅ -alkyl or a C. ₅ ₁₂ -cycloalkyl radical or a C ₆ ₁₄ alkyl radical,

B styrene or C ₁ . _3- alkyl substituted styrenes,

the copolymer consisting of 60 to 98% by weight of A and 2 to 40% by weight of B, (total = 100% by weight).

4. High-strength polyester threads according to claim 3, characterized in that the copolymer consists of 83 to 98% by weight of A and 2 to 17% by weight of B (total = 100% by weight).

5. High strength polyester threads according to claim 3 or 4, characterized in that the copolymer consists of 90 to 98 wt .-% A and 2 to 10 wt .-% B (sum = 100 wt .-%).

6. High-strength polyester threads, according to claims 1 or 2, characterized in that the polymeric additive β) is a copolymer which contains the following monomer units:

C = styrene or C ^ alkyl-substituted styrenes,

one or more monomers of the formula I, II or III

R-C = C-R ₂ R-C-COOH R-C-C = 0

II \ n

0 = c _/ c = o R-C-COOH R ₇ -C-C = 0

(I) (II) (III) where R _ls R ₂ and R _{3 are} each an H atom or a C _:. ₁₅ -Al yl radical or a C ₅ _ ₁₂ cycloalkyl radical or a C ₆ _ ₁₄ aryl radical, and wherein the copolymer consists of 15 to 95% by weight of C and 5 to 85% by weight of D, the Sum of C and D together gives 100%.

7. High strength polyester threads according to claim 6, characterized in that the copolymer consists of 50 to 90 wt .-% C and 10 to 50 wt .-% D, the sum of C and D together making 100%.

8. High-strength polyester threads according to claims 6 or 7, characterized in that the copolymer consists of 70 to 85 wt .-% C and 30 to 15 wt .-% D, the sum of C and D together making 100%.

9. High-strength polyester threads, according to claims 1 or 2, characterized in that the polymeric additive β) is a copolymer which contains the following monomer units:

E = acrylic acid, methacrylic acid or CH ₂ = CR - COOR ¹ , where R is an H atom or a CH ₃ group and R 'is a C 1-6 alkyl radical or a C ₅ . ₁₂ -Cycloal kyl rest or a C ₅ . ₁₄ aryl radical,

F = styrene or C, _ ₃ -alkyl-substituted styrenes,

G = one or more monomers of the formula I, II or III

R, -C = C-R ₂ R-C-COOH R-C-C = 0

II II II) oo = c _/ c = o R ₂ —C- -C00H R ₇ —C — C = 0

R where R _1} R ₂ and R _{3 are} each an H atom or a C _:. ₁₅ - alkyl radical or a C ₅ . ₁₂ -Cycloal kyl rest or a C ₆ . ₁₄ - aryl radical,

H one or more ethylenically unsaturated with E and / or with F and / or G copolymerizable monomers from the group consisting of α-methyl styrene, vinyl acetate, acrylic acid esters, methacrylic acid esters, which are different from E, vinyl chloride, vinylidene chloride, halogen-substituted styrenes, vinyl ethers .

Isopropenyl ethers and dienes,

wherein the copolymer consists of 30 to 99% by weight of E, 0 to 50% by weight of F,> 0 to 50% by weight of G and 0 to 50% by weight of H, the sum of E, F, G and H together gives 100%.

10. High-strength polyester threads according to claim 9, characterized in that the copolymer consists of 45 to 97% by weight of E, 0 to 30% by weight of F, 3 to 40% by weight of G and 0 to 30% by weight of H. , where the sum of E, F, G and H together makes 100%.

11. High-strength polyester threads according to claim 9 or 10, characterized in that the copolymer of 60 to 94 wt .-% E, 0 to 20 wt .-% F, 6 to 30 wt .-% G and 0 to 20 wt .-% % H exists, the sum of E, F, G and H together making 100%.

12. A method for producing the high-strength polyester threads according to any one of claims 1-11, characterized in that a) a polyester α) containing terephthalate containing at least 85 mole% of poly (C. ₂ ₄ alkylene), and

0.1 to 2.0% by weight of an incompatible, thermoplastically processable, amorphous polymeric additive β) which has a glass transition temperature in the range from 90 to 170 ° C., the ratio of the melt viscosity of the polymeric additive β) to the melt viscosity of the polyester component α) is 1: 1 to 7: 1,

where these can contain 0 to 5.0% by weight of conventional additives γ),

mixed in the molten state in a static mixer under shear, the shear rate being 16 to 128 sec ^"1 , and the product of the shear rate and the 0.8th power of the residence time in seconds in the mixer is set to a value of at least 250;

b) the melt mixture from stage a) is spun into filaments, the spinning take-off speed being> 700 to

Is 1500 m / min; and

c) the filaments from stage b) are drawn, heat-set and wound up, the drawing ratio being at least 1: 5.

13. A method for producing high-strength polyester threads according to claim 12, characterized in that the spinning take-off speed is 750 to 1000 m / min.

4. A process for the production of high-strength polyester threads according to one of claims 12 to 13, characterized in that the concentration C of the polymeric additive in the range 0.1 to 2.0 wt .-% is selected so that the birefringence of the spun threads <3 , 5 ^• 10 ^"3 is.