IE922193A1 - High tenacity polyester yarn and production thereof - Google Patents

Abstract

A polyester yarn having a novel property combination of high strength, high modulus and low heat shrinkage is described, which is to be produced by high-speed spinning, and a spinning yarn suitable for its production composed of a polyester raw material based on a modified polyethylene terephthalate which contains as modification components, relative to the total acid components, 0.5 - 5.0 mol % of radicals of aliphatic dicarboxylic acids having in total at least 5 C atoms and/or aromatic dicarboxylic acids whose carbonyl bonds are angled or whose aromatic rings carry modification-active substituents, and/or, relative to the total diol components, contains 0.5 to 5 mol % of alkane or cycloalkane diols having 3 to 10 C atoms, di- or tri-ethylene glycol or polyethylene glycol having a molecular weight of up to 4000, has a specific viscosity, measured in a solution of 1 g of the polyester in 100 ml of dichloroacetic acid at 25 DEG C of 0.8 - 1.7, and in that, when it is spun at a spinning take-off rate Va, the quotient Q of double refraction and crystallinity corresponds to the formula 11.86 - 3.94.10<-3> DOLLAR Va + 4.57.10<-7> DOLLAR (Va)<2> > Q > 10.86 - 3.94.10<-3> DOLLAR Va + 4.57.10<-7> DOLLAR (Va)<2> (III)

Description

High tenacity polyester yarn and production thereof Description The present invention relates to a high tenacity, low shrinkage polyester yarn, produced by high speed spinning, which is optimizable in particular in the form of cords, weaves, braids, etc. for various technical purposes, for example for use as load-bearing component in technical products such as awnings, conveyor belts, hoses, V-belts, tires, etc., to a process for producing this yarn, and to the polyester raw material required for said process.

The production of high tenacity yarns made of polyester filaments is known. According to German Auslegeschrift 1288734, the spinning conditions must be selected for this purpose in such a way that the tensions acting on the solidifying filament are unusually low and the asspun filament therefore has a very low molecular orientation. Birefringence values of less than 0.003, preferably even less than 0.002, are stipulated. If such as-spun filaments are later subjected to drawing to a high draw ratio it is possible to obtain yarns having high strengths. The tenacity of such yarns is about 76 cN/tex and their breaking extension is 11%. However, such a yarn still possesses a high thermal shrinkage; for example, in hot air at 200C it is still about 18%. It has become customary to determine the thermal shrinkage at 200*C, since in general 200*C is the highest tempera30 ture which can arise in the coating of fabrics made of such yarns. A yarn material which still has a shrinkage of for example 18% leads to severe and uncontrollable dimensional changes in such a coating process. It is therefore necessary to reduce the thermal shrinkage. This is usually done in thermomechanical shrinkage processes - 2 in which the yarn is shrunk under controlled tension. In this way it is possible, for example, to reduce the thermal shrinkage at 200eC to, for example, 5%. However, this measure leads inevitably also to changes in other properties: increasing the ultimate tensile strength extension, for example to 16% reducing the tenacity from, for example, 76 cN/tex to 72 cN/tex - flattening the stress-strain diagram, i.e. reducing the modulus, expressed for example in terms of the extension under a certain load (reference extension) reducing the shrinkage force.

A high modulus or a low reference extension and suffi15 ciently high shrinkage force coupled with low shrinkage are advantageous in a heat treatment of fabrics, for example in a coating operation, since they counteract any dimensional change due to deformation.

A high modulus and high strength coupled with low shrink20 age is also required for the thermal stability of nontire rubber goods such as, for example, V-belts.

The requirement of high strength and high modulus coupled with low shrinkage has hitherto been difficult to meet, since all thermomechanical measures for reducing thermal shrinkage also result in an impairment of the required properties such as tenacity, breaking extension, modulus and shrinkage force.

To obtain the high strengths required for example of yarns as load-bearing components in coated fabrics or as reinforcing threads for conveyor belts and hoses inevitably also requires, according to the teaching of the above-cited German Auslegeschrift, low spinning takeoff speeds. However, a low spinning takeoff speed also means a lower output per spinneret and hence uneconomical processing.

|E 922193 It is known that a sharp increase in the output per spinneret is obtained with increasing spinning takeoff speed, as represented for example in Figure 1 of German Offenlegungsschrift 2207849. It is also known that, as the spinning takeoff speed increases, the slope of the stress-strain curve, i.e. the modulus, increases, the thermal shrinkage decreases and the shrinkage force increases, but that the attainable tenacity also sharply decreases. It is therefore not surprising that yarns produced by high speed spinning have hitherto been predominantly used for purposes where dimensional stability (high modulus coupled with relatively low shrinkage) is more critical than yarn strength, such as, for example, in the tire cord sector, where it is not the strength of the yarn but the strength in the latexed cord which is decisive.

Table 3 of US Patent 4,491,657 illustrates the decreasing yarn strength of yarns produced by high speed spinning but also the virtually unchanged cord strength compared with yarns produced by low speed spinning, which makes it possible to use these high speed yarns for example as tire cord. According to this disclosure a spinning speed of 3000 m/min results in yarn strengths of only 61 cN/tex.

Similarly, the most recent publication about high speed spinning processes (WO 90/00638) gives maximum yarn strengths of 68.9 cN/tex at spinning speeds of 2900 m/min (Tables 2 and 5), which does not meet the requirements for use in coated fabrics or as reinforcing threads, for example for conveyor belts or hoses.

For industrial yarns for other purposes, for example as load-bearing components in coated fabrics or as reinforcing threads for conveyor belts and hoses, the yarn strength is of eminent importance, in combination with other technically relevant data which need to be optimized for the various uses. For instance, yarns for coating support fabrics should have at least a high breaking strength of > 70 cN/tex, a low hot air shrinkage of < 5% and a high yarn cleanness, i.e. minimum number of filament breakages (snarls). It would be advantageous to have at the same time a high modulus and a sufficiently high shrinkage force.

Yarns which are to be used as reinforcing threads, for example in conveyor belts or hoses, must have a particularly high strength of >75 cN/tex coupled with a heat shrinkage of < 10%.

Owing to these high requirements, in particular owing to the requirement of high yarn strength coupled with low heat shrinkage and also good mechanical quality (no filament breakages), such yarns have hitherto been produced in industry only at low spinning speeds of < 1000 m/min.

For the abovementioned reasons, in particular on account of the beneficial increase in the output per spinneret and the increase in the modulus/shrinkage ratio, it is desirable, however, to produce industrial yarns in general by a high speed spinning process.

German Patent 3,431,831 discloses for example a process for producing industrial yarns from a feed yarn spun at a high spinning takeoff speed of up to 3000 m/min, whereby it is possible to produce yarns which, as evidenced by the examples in this publication, can reach tenacities of up to 72.5 cN/tex. However, these yarns still leave something to be desired in respect of the combination of the abovementioned technically relevant properties. For instance, the attainable tenacity, even in the case of substantial utilization of the drawing potential, is still distinctly below that of yarns spun at low speeds. In particular, it is not possible to meet the requirement of high tenacity coupled with low heat shrinkage to the desired extent.

For instance, Examples 7 and 8 in the table on page 24 of the abovementioned Offenlegungsschrift show that relaxing to values which are required for example for coating supports makes the tensile strength drop to inadequate values. Moreover, it is known from experience that with these high speed spinning yarns it is likewise impossible, on account of the substantial drawing, to achieve the required yarn cleanness, i.e. minimal filament breakages .

It has now been found, surprisingly, that it is possible to produce high tenacity polyester yarns with a combination of properties desirable for industrial use even by high speed spinning, i.e. by spinning at spinning takeoff speeds above 2500 m/min, by starting from a specific polyester raw material based on a modified polyethylene terephthalate.

In what follows, reference is made to Figures 1 and 2. Figure 1 shows graphic representations of the formula II (curve 1) and of the right-hand side of the formula III (curve 2) and also a representation of the dependence of the quotient Q on the spinning speed for a known polyester raw material (curve 3).

The area between curves 1 and 2 denotes the position of preferred polyester raw materials according to the invention.

Figure 2 shows a graphical representation of the relation of birefringence and crystallinity of as-spun yarns produced at the same spinning takeoff speed from a known polyester raw material (curve 1) and from a polyester raw material according to the invention (curve 2).

The specific polyester raw material to be used according to the invention contains as modifying components, based on the total acid components, 0.5-5.0 mol% of radicals of aliphatic dicarboxylic acids having a total of 5 carbon atoms and/or aromatic dicarboxylic acids whose carbonyl bonds are disposed angled or whose aromatic nuclei carry modifying substituents and/or, based on the total diol components, 0.5-5.0 mol% of alkane- or cycloalkane-diols of from 3 to 10 carbon atoms, di- or triethylene glycol or polyethylene glycol having a molecular weight of up to 4000. The average molecular weight of the polyester to be used according to the invention corresponds to a specific viscosity, measured in a solution of 1 g of the polyester in 100 ml of dichloroacetic acid at 25*C, of 0.8-1.7, preferably 1.1-1.5. An essential characteristic of the polyester to be used according to the invention is that on spinning at a spinning takeoff speed (V.) within the range 2500 < V. < 4000 m/min the quotient (Q) of birefringence (Br) and crystallinity (K) as per formula I of the resulting as-spun yarn (i.e. the yarn obtained directly in spinning without any further treatment operation) lies above curve 1 in Fig. 1, or corresponds to the formula II: Q = Br x 1000/K (I) Q > 10.86 - 3.94 x ΙΟ'3 x V. + 4.57 x ΙΟ'7 x (V.)2 (II) The present invention provides an as-spun yarn comprising this polyester raw material and obtained therefrom by high speed spinning at spinning takeoff speeds above 2500 m/min, for example at from 2500 to 6500 m/min or else, depending on the spinning plant, higher.

It is to be expressly noted that the above-spec if ied speed range of from 2500 to 4000 m/min merely serves for testing and characterizing the polyester raw material according to the invention.

If an as-spun yarn produced within this speed range meets the con-ditions of the formula II, then the polyester raw material in question is characterized as utilizable according to the invention, i.e. as a suitable raw material for producing the as-spun yarn according to the invention. Such a raw material can then of course also be spun into said yarn according to the invention at higher speeds than 4000 m/min.

The above-indicated modifying components incorporated in 5 the polyester to be used according to the invention have significant bearing on the crystallization characteristics of the as-spun yarn and are therefore selected from the above-specified group in such a way that the quotient of optical birefringence and crystallinity according to formula I of the as-spun yarn produced therefrom meets the condition defined by the formula II.

Aromatic and aliphatic dicarboxylic acids which can be incorporated into the polyester according to the invention are for example isophthalic acid, sulfoisophthalic acid, methylterephthalic acid, chloroterephthalic acid, methylisophthalic acid, chloroisophthalic acid, 3- or 4-carboxyphenylacetic acid, naphthalene-1,3-, -1,6-, -2,5- or -2,7-dicarboxylic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid or sebacic acid. Diols which can be incorporated as modifiers into the polyester of the invention and to be used according to the invention are for example propanediol, butanediol, pentanediol, dimethylpropanediol, octanediol, isooctanediol, cyclohexanediol, bishydroxymethylcyclohexane, diethylene glycol (= dihydroxydiethyl ether), triethylene glycol (= bis(2-hydroxyethoxy)ethane), and polyethylene glycol or polypropylene glycol having average molecular weights of up to about 4000.

Preference is given to a polyester raw material according to the invention containing as modifying components, based on the total acid components, 0.5-5.0 mol%, preferably from 1 to 3 mol%, of radicals of aliphatic dicarboxylic acids having a total of at least 5 carbon atoms and/or aromatic dicarboxylic acids whose carbonyl bonds are disposed angled.

For use in industry a particularly preferred modifying acid component is isophthalic acid, preferably in amounts β of 0.5-5% by weight, in particular from 1 to 2.5% by weight. Preferred diol components are diethylene glycol, advantageously present in the polyethylene terephthalate in a proportion of from 0.5 to 3% by weight, in particular from 1 to 2% by weight, and for example bishydroxymethyl-cyclohexane, advantageously present in the polyethylene terephthalate in the above-specified proportions of from 0.5 to 5% by weight, preferably from I. 5 to 3% by weight.

The polyethylene terephthalate can also contain combinations of modifying acid and diol components, for example from 0.5 to 2.5% by weight, preferably from 1 to 2% by weight, of isophthalic acid and from 0.5 to 2.5, preferably from 1 to 2, % by weight of diethylene glycol.

The modifying is controlled within the scope of the above directions in such a way that the polyester meets the specification defined by the formula II.

Particular preference is given to those polyester raw materials where the quotient Q of birefringence and crystallinity of the yarn produced therefrom lies between the curves 1 and 2 in Fig. 1 or corresponds to the formula III II. 86 - 3.94 χ ΙΟ*3 χ V. + 4.57 χ ΙΟ'7 χ (V.)2 > Q > 10.86 - 3.94 x 10‘3 χ Va + 4.57 χ ΙΟ7 χ (V,)2 (III) Preference is also given to those polyester raw materials and yarns produced therefrom which contain no pigmenting agents.

The use of modified copolyesters for producing high tenacity multifilament yarns for industrial purposes has been only comparatively rarely described in the literature. For instance, a number of Japanese patent applications claim the use of raw materials containing different proportions of 4,4'-biphenylcarboxylic acid as comonomer. More specifically, the polyester according to JP-A-57 143 516 and JP-A-57 143 517 contains a proportion - 9 of 45-74 mol% of the comonomer, which goes far beyond a customary modification of polyethylene terephthalate. In JP-A-53 006 621 and JP-A-51 082 019, by contrast, only additions of 0.5-5 mol% and of > 10% by weight, respec5 tively, of ethylene 4,4'-biphenylcarboxylate units are described as modifying component. However, none of these Japanese patent applications makes any mention of a high speed spinning process. Moreover, the use of 4,4'-biphenyldicarboxylic acid appears to be too costly for bringing about the improvements according to the invention.

The preparation of a copolyester of reduced softening temperature containing 2,2',6,6'-tetramethylbiphenyl4,4'-dicarboxylic acid as cocomponent is described in US-A-40 35 342. However, the possibility of processing this raw material by a high speed spinning process is not in any way suggested there. Moreover, a sharp reduction in the softening temperature has a disadvantageous effect, for example in the event of hot coating the yarns produced therefrom.

JP-A-52 152 514 describes aromatic diol components and JP-A-57 149 511 mixed-functional monomers, for example p-hydroxybenzoic acid, for use as modifying components. It must be assumed that these chain-stiffening monomers have if anything a disadvantageous effect in high speed spinning. These monomers are therefore not suitable for modifying polyethylene terephthalate according to the invention. The same is true of the addition of diamines and aminocarboxylic acids described respectively in JP-A-55 137 217 and JP-A-55 067 009.

JP-A-63 059 412 and JP-A-53 130 351 concern improvements obtained by ueing polytrimethylene terephthalate, polytetramethylene terephthalate or polyhexamethylene terephthalate or blends of these or similar or corresponding polyisophthalates with polyethylene terephthalate. The polymers in question are autonomous polymers or mixtures of various polymers, but not modifiers within the meaning of the present invention.

The test of a modified polyester raw material to be used according to the invention to see whether it meets the conditions defined by the formulae II or III can be effected by spinning a sample of the raw material at a spinning takeoff speed of from 2500 to 4000 m/min and determining the birefringence and the crystallinity on the resulting as-spun yarn. Thereafter the quotient of the two values is formed and used to test whether the conditions stipulated by the formulae are met.

The birefringence of the as-spun yarns is determined in a known manner by means of a polarizing microscope.

The crystallinity is usually calculated from the density d of the filaments by the following equation: dk(d-d.) Crystallinity (%) = d(dk-da) The density d of the filaments will be determined in a 20 known manner with the aid of a density gradient column (density range 1.35-1.45 g/ml; aqueous zinc salt solution). The density of the amorphous portion d. has been assumed to be 1.331 g/ml and the density of the crystalline material dk has been assumed to be 1.455 g/ml.

If the as-spun yarns according to the invention were produced from the above-described modified polyester raw material at a spinning takeoff speed V, of from 2500 to 4000 m/min they by definition meet the formula Q > 10.86 - 3.94 χ ΙΟ*3 χ V. + 4.57 χ ΙΟ'7 χ (V.)2 II where Q is the quotient of birefringence and crystallinity as per the formula I.

It is clear from the above formula that, depending on the -lispinning takeoff speed at which it was produced, the as-spun yarn according to the invention exhibits a particular characteristic combination of molecular orientation, expressed by the value of the optical birefringence, and crystallinity. Compared with as-spun yarns from conventional, unmodified polyesters the as-spun yarn according to the invention has for the same orientation a significantly lower crystallinity or for the same crystallinity a significantly higher orientation. In the graphic representation of Fig. 2, where the birefringence has been plotted as a measure of the orientation versus the asspun crystallinity, this relation is expressed very clearly.

For example, the as-spun yarn according to the invention has, depending on the spinning takeoff speed V, at which it was produced, a quotient of birefringence and crystallinity according to the formula I as follows: V,: 2500 - 3000 m/min Q: > 3.5 V,: 3000 - 3200 m/min Q: > 3.1 V,: 3200 - 3400 m/min Q: > 2.8 V,: 3400 - 3800 m/min Q: > 2.5 V,: 3800 - 4200 m/min Q: > 2.4 The influence of polyester additives on crystallization characteristics is indicated in the literature. For instance, Japanese Patents No. 58 079 012 and No. 58 065 719 describe for example raw materials which in high speed spinning are likewise said to result in high orientation and low crystallinity of the resulting yarn. However, this effect is achieved not by using a copolyester but by adding sulfurous or antimonous acid or salts thereof to ordinary polyethylene terephthalate.

The same effect is achieved in JP-A-58 047 020 by adding basic sodium or potassium salts and according to JP-A-58 096 624 by adding sodium or potassium alcoholates and also carboxylic anhydrides. None of these cases amount to genuine modification through incorporation of copolymers in the polyester.

A high as-spun shrinkage and a high birefringence at a spinning takeoff speed of 3000 m/min can be achieved according to JP-A-60 071 710 by introducing aliphatic carboxylic acid radicals as end groups. Polyesters modified in this way are said to have advantages for textile purposes. The production of high tenacity industrial filaments is not described.

The as-spun yarn according to the invention can be used 10 as described hereinafter for producing high tenacity yarns for industrial purposes. In this the as-spun yarn according to the invention has the useful advantage that through suitable choice of the further processing conditions it is better optimizable for specific industrial purposes than conventional as-spun yarn.

The present invention further provides the process for further processing the above-described as-spun yarn to give high tenacity polyester yarns for industrial use. This process comprises subjecting the as-spun yarn produced from the above-described polyester raw material at a high spinning speed to single- or multiple-stage drawing at high temperatures. This drawing can take place continuously over takeoff and drawing godets, but preferably is carried out batchwise on a godet production line, maintaining a drawing tension between 20 and 33 cN/tex, preferably between 23 to 29 cN/tex.

The present invention also provides the high tenacity polyester yarn producible by this process from the asspun yarn produced by high speed spinning, the polyester containing as modifying components, based on the total acid components, 0.5-5.0 mol% of radicals of aliphatic dicarboxylic acids having a total of 5 carbon atoms and/or aromatic dicarboxylic acids whose carbonyl bonds are disposed angled or whose aromatic nuclei carry modifying substituents, and/or, based on the total diol components, 0.5-5.0 mol% of alkane- or cycloalkane-diols of from 3 to 10 carbon atoms, di- or triethylene glycol or polyethylene glycol having a molecular weight of up to 4000 and having a specific viscosity, measured in a solution of 1 g of the polyester in 100 ml of dichloroacetic acid at 25“C, of 0.8-1.7, preferably of 1.1-1.5, and the yarn combining the following data: ultimate tensile strength: > 70 cN/tex 10 ultimate tensile strength extension: < 15% reference extension (54 cN/tex): < 12% hot air shrinkage at 200°C: < 8% shrinkage force at 190*C: > 0.30 cN/tex, and the hot air shrinkage at 200’C (HAS200) relating to the ultimate tensile strength (UTS) as follows: HAS200 < UTS - 67.

(Hereinbefore and hereinafter the term ultimate tensile strength is used in short for ultimate tensile strength per unit linear density.) As mentioned earlier, by varying the process parameters it is possible to achieve excellent adaptation of the yarn properties to the intended use.

For instance, it is possible by permitting a low shrinkage of about 4 to 10% in the last drawing stage to produce high tenacity yarns of particularly low hot air shrinkage, which can be used for example as loadbearing components in coated fabrics. The necessary heating of the yarns is effected here by way of heated godets or a hot setting duct. Such a high tenacity polyester yarn produced from modified polyethylene terephthalate by high speed spinning exhibits a combination of the following data: ultimate tensile strength > 70 cN/tex ultimate tensile strength extension: < 15% reference extension (54 cN/tex): < 12% hot air shrinkage at 200°C: < 3% shrinkage force at 190’C: > 0.30 cN/tex or, if a somewhat higher modulus is set, a dramatically increased shrinkage force within the following combination of properties: ultimate tensile strength: >71 cN/tex 5 ultimate tensile strength extension: < 13% reference extension (54 cN/tex): < 10% hot air shrinkage at 200*C: < 4% shrinkage force at 190’C: > 0.75 cN/tex or: ultimate tensile strength: > 74 cN/tex ultimate tensile strength extension: < 12% reference extension (54 cN/tex): < 9% hot air shrinkage at 200eC: < 7% shrinkage force at 190eC: > 1.0 cN/tex.

Without or with only little relaxation (< 4%) and with or without heat treatment it is possible to produce highspeed-spun industrial polyester yarns having extremely high tenacities of above 75 cN/tex, which are preferably usable as reinforcing threads in conveyor belts, hoses and V-belts but are also utilizable as tire cord with distinctly improved yarn strength, in particular when the reguired dimensional stability is achieved at high spinning speeds. If no shrinkage is permitted the resulting yarns have for example the following combinations of properties: ultimate tensile strength: > 75 cN/tex ultimate tensile strength extension: < 10% reference extension (54 cN/tex): < 7% hot air shrinkage at 200*C: < 8%. or in the case of spinning takeoff speeds > 3500 m/min: ultimate tensile strength: > 73.5 cN/tex ultimate tensile strength extension: < 10% reference extension (54 cN/tex): < 7% hot air shrinkage at 200*C: < 6.5%.

Particular preference is given in particular also to those objects according to the invention that comprise a combination of a plurality of preferred features.

The following embodiment examples illustrate the working 5 of the invention and demonstrate the surprising technical advantages associated therewith.

Examples The examples according to the invention were carried out using a pigment-free copolyester of modified polyethylene terephthalate containing 1.6% by weight of isophthalic acid as sole modifying component.

The comparative examples were carried out using a commercial, fiber manufacture polyethylene terephthalate which was pigmented with 0.04% by weight of TiO2. The difference in the quotients of birefringence and as-spun crystallinity as per formula I for the comparative raw material as a function of the spinning takeoff speed V. compared with the modified polyester according to the invention is clear from curve 3 in Fig. 1.

The specific solution viscosity of the polyester raw material according to the invention and that of the comparative raw material are within the range from 0.8-1.7, preferably from 1.1-1.5.

The relative solution viscosity was customarily deter25 mined on solutions of 1.0 g of the polymer in 100 ml of dichloroacetic acid at 25 °C by measuring the flow times of the solution through a capillary viscometer and by determining the flow time of the pure solvent under the same conditions. The polyethylene terephthalate chips used were melted in an extruder, delivered to a spinning pump and spun through a spinning pack. The spinneret plate in the spinning pack had in each case 200 holes each 0.6 mm in diameter.

The filaments were jointly delivered to a spin finish applicator means, provided with a spin finish and taken off and wound up at the speeds indicated in the tables.

Depending on the degree of orientation of the as-spun material, the filaments were then drawn under various conditions and on various drawing machines and partially shrunk.

The spinning and drawing conditions maintained in the individual runs are indicated below in the tables.

In a first series of runs the conditions for producing yarns for coating supports were established. The data relating to this series are found in Tables 1 and 2, Table 2 showing in particular the data obtained in a simulation of industrial production using a high line speed (> 250 m/min) and a large number of filaments (> 250 filaments). The yarn cleanness is also recorded in terms of snarl density.

In a second series of runs the conditions for producing yarns for reinforcing purposes were established. The data relating to this series are given in Table 3.

In the tables below the term breaking strength is used in place of ultimate tensile strength (UTS). - 17 Table 1 Examples of the preparation of yarns for coating supports C •H 4-) E u o C o 00 o • • •H 00 CN B Φ > σι B w co •H • • 00 co Φ £ 4-> 00 0 co 0 +J • • 00 CO O' B •H Ό Γ- M r* • 0 o CN U U <0 K LO Φ © r* 4-) • * (0 σι co Φ >1 Γ—1 0 m CL, CN m 00 * 00 m • • f** cn kl in m Φ • 4-1 r* CN (0 rH Φ >1 0 LO m CN CX • • w* cn Ό l-l <0 Ό C σ\ rH (0 • • 4-1 CN ω *H 4-) (0 4-) E a 0 •H Φ n O' B a Φ X 4J — B K <#> •H Φ M £ Φ 0) X n — Λ U Φ dP ΐ B 4-) u ~ 9 Φ >L •H C C4 Z « t_> Φ u • C 4-) O 9 Φ 0 © 06 K m 3LCL Shrinkage force at 0.47 0.42 0.26 1.37 1.22 0.82 0.33 0.89 0.93 0.88 |at 190*C (cN/tex) _ Table 2 Preparation of coating support yarns under production conditions Run number 12 3 Standard Polyester according polyester to the invention n.p.c (drawn yarn) 1.05 1.20 1.20 Takeoff speed (m/min) 700 2800 3000 Drawing speed (m/min) 300 240 275 Linear density (dtex) 1125 1154 1176 Breaking strength (cN/tex) 73.0 63.1 71.4 Breaking extension (%) 19.7 12.3 12.3 Reference extension at 54 cN/tex (%) 14.6 8.7 9.1 Shrinkage at 200°C (%) 3.5 3.4 3.8 Shrinkage force at 190°C (cN/tex) 0.42 1.14 0.82 Snarls1’ small/large ;n/100 km) 15/0.4 31/1.4 22/0.5 1): optoelectronic method of measurement in the course of cording. - 20 Table 3 Examples of preparation of reinforcing yarns (conveyor belts, pressure hose and the like) c 14 o o f-4 0 • σι f*4 •H iH co o P c Φ > c 14 o o f-4 • σι the co o σι o fM © 4J • σ* c •H Ό m co o 00 u o o • o fH PO u a o o r* Φ 4J CM o • o a fl io Φ >1 c—4 0 cu .14 o o o m 14 1 m o © fH fH PM o o P fH 00 PO o co Φ fH © P • ω fH co PM Φ P Si 14 o o Ό fH o co f-4 M a Ό c a 05 o P • © cn t—1 ber awn yarn) g takeoff (m/min) c H Ό c P C c u • c •H 9 a a cu K cr cn 90 90 255 255 100 100 1 1 o m o σ' © © 1 CN o m © σι m o 1 Cl F4 o © o σι m o 1 CJ w o m o σι © © 1 CJ o m © σι m © 1 CJ fH o m o σι m © 1 CJ fH o © © σ' © © 1 Cl fH o m o σ' m © J CJ fH m m in co ao m r* fH CJ CJ CM + u co • a P P P P υ P u e 9 c 9 s3 TJ 9 TJ 9 ®* O' O' O' P C c c e Λ M P P P M * > P ffl 10 a a P XU M M Φ 6° o o cn Φ El o o in o P> o cn Ο a P P P P <0 c M 9 c MM TJ » Φ β Μ M Pl Ο- in σι fH p* 00 P* *· σι • σι fH • • © • fH o OD fH CJ o 00 © CN co r* © σι * © • σι m • • • • co 00 fH Cl o fH P* m © r~ © © fH © • © o • • • © « f4 © 0 PM CN o f-4 m m CJ Cl p* Cl © ID σι • σι in • • • w· • fH m © CJ o fH p* m m o r* fH N· o • © © • • • © • fH © CJ Cl o © m ID Cl (** CJ PM P* o « σι m • • • • fH 00 00 CJ Cl © P* in r* σι p* P* CJ c* • σι σι • • • co • © fH » r-4 CN o fH © m 00 O Is* co © © • σι • • « • © © f-4 CJ © ID m o Cl r* σι σι ID © • σι p* • • • • o σι 00 CJ Cl o fH ID m o p* P P* rd « © o • • • w· • o © CN CN o f*4 r~ σι in © ID o P* CO σι Cl P* • • CN • fH CJ © o fH fH ρο C 0 m a a p -+ C M > a c a P 9 O' O'2 C 9 I Μ M ' » > a a M M CQti c o M P a x a r-1 βί K Φ P •o >1 P P a e φ TJ M a φ c £ P 0» c Φ M P a O' -.

C K P Φ X P a Φ z M 0 co —* c P a c Φ P M Φ Breaking ,E 922193 12 3 4 5 67 89 10 11 Standard polyester Polyester according to the invention 7.8 6.1 6.0 6.3 6.2 5.8 5.4 5.7 5.4 5.6 5.5 8.5 5.4 5.1 4.4 3.9 7.0 7.1 6.6 6.8 6.1 6.1 Run number Reference extension at 54 cN/tex (%) Shrinkage at 200’C (%)

Claims (23)

What is claimed is:

1. An as-spun yarn for producing synthetic fibers combining high strength with relatively low hot air shrinkage by high-speed spinning, comprising a polyester raw material based on a modified poly-ethylene terephthalate which contains as modifying components, based on the total acid components, 0.5-5.0 mol% of radicals of aliphatic dicarboxylic acids having a total of 5 carbon atoms and/or aromatic dicarboxylic acids whose carbonyl bonds are disposed angled or whose aromatic nuclei carry modifying substituents and/or, based on the total diol components, 0.5-5.0 mol% of alkane- or cyclo-alkanediols of from 3 to 10 carbon atoms, di- or triethylene glycol or polyethylene glycol having a molecular weight of up to 4000, whose average molecular weight corresponds to a specific viscosity, measured in a solution of 1 g of the polyester in 100 ml of dichloroacetic acid at 25°C, of 0.8-1.7, preferably 1.1-1.5, and which on spinning at a spinning takeoff speed V, produces an as-spun yarn which satisfies the formula II Q > 10.86 - 3.94 Χ 10' 3 X V, + 4.57 X 10' 7 X (V.) 2 II where Q is the quotient of birefringence and crystallinity of the resulting as-spun yarn.

2. The as-spun yarn of claim 1, comprising a polyester raw material based on a modified polyethylene terephthalate which as modifying component contains, based on the total acid components, 0.5-5.0 mol% of radicals of aliphatic dicarboxylic acids having a total of 6 carbon atoms and/or aromatic dicarboxylic acids whose carbonyl bonds are disposed angled or whose aromatic nuclei carry modifying substituents. IE 92219 3 - 23

3. The as-spun yarn of either of claims 1 and 2, comprising a polyester raw material based on a modified polyethylene terephthalate which as modifying component contains, based on the total diol components, from 0.5 to 5.0 mol% of radicals of diethylene glycol or of bishydroxymethylcyclohexane.

4. The as-spun yarn of at least one of claims 1 to 3, comprising a polyester raw material based on a modified polyethylene terephthalate which as modifying component contains radicals of isophthalic acid.

5. The as-spun yarn of at least one of claims 1 to 4, comprising a polyester raw material based on a modified polyethylene terephthalate in which the modifying acid component is present in a proportion of from 1 to 3 mol%.

6. The as-spun yarn of at least one of claims 1 to 5, comprising a polyester raw material based on a modified polyethylene terephthalate which on spinning at a spinning takeoff speed V, produces a filament yarn which satisfies the formula III 11.86 - 3.94 X ΙΟ 3 X V. + 4.57 X ΙΟ’ 7 χ (V.) 2 > Q > 10.86 3.94 X ΙΟ’ 3 X V. + 4.57 X ΙΟ' 7 X (V a ) 2 (III) where Q is the quotient of birefringence and crystallinity of the resulting as-spun yarn.

7. The yarn of at least one of claims 1 to 6, wherein the following relation exists between the spinning takeoff speed crysta V, and llinity: the quotient of birefringence V.: 2500 - 3000 m/min Q: > 3.5 V.: 3000 - 3200 m/min Q: > 3.1 V.: 3200 - 3400 m/min Q: > 2.7 V.: 3400 3800 m/min Q: > 2.5

8.

9. - 24 V.: 3800 - 4200 m/min Q: > 2.4 The as-spun yarn of at least one of claims 1 to 7, containing no pigmenting agents. A process for producing the as-spun yarn of claim 1 by spinning a polyester at a spinning takeoff speed above 2500 m/min, which comprises using as polyester a modified polyethylene terephthalate which contains as modifying components, based on the total acid components, 0.5-5.0 mol% of radicals of aliphatic dicarboxylic acids having a total of 5 carbon atoms and/or aromatic dicarboxylic acids whose carbonyl bonds are disposed angled or whose aromatic nuclei carry modifying substituents and/or, based on the total diol components, 0.5-5.0 mol% of alkane- or cyclo-alkanediols of from 3 to 10 carbon atoms, di- or triethylene glycol or polyethylene glycol having a molecular weight of up to 4000, whose average molecular weight corresponds to a specific viscosity, measured in a solution of 1 g of the polyester in 100 ml of dichloroacetic acid at 25°C, of 0.8-1.7, preferably 1.1-1.5, and which on spinning at a spinning takeoff speed V, produces an as-spun yarn which satisfies the formula II Q > 10.86 - 3.94 X 10' 3 X V, + 4.57 X 10’ 7 X (V,) 2 II where Q is the quotient of birefringence and crystallinity of the resulting as-spun yarn. A high tenacity polyester yarn produced from modified polyethylene terephthalate by high speed spinning, the polyethylene terephthalate containing as modifying components, based on the total acid components, 0.55.0 mol% of radicals of aliphatic 10. - 25 dicarboxylic acids having a total of 5 carbon atoms and/or aromatic dicarboxylic acids whose carbonyl bonds are disposed angled or whose aromatic nuclei carry modifying substituents, and/or, based on the 5 total diol components, 0.5-5.0 mol% of alkane- or cycloalkane-diols of from 3 to 10 carbon atoms, dior triethylene glycol or polyethylene glycol having a molecular weight of up to 4000 and having a specific viscosity, measured in a solution of 1 g of the

10 polyester in 100 ml of dichloroacetic acid at 25’C, of 1.0-1.35, and the yarn combining the following data: ultimate tensile strength: > 70 cN/tex ultimate tensile strength extension: < 15% 15 reference extension (54 cN/tex): < 12% hot air shrinkage at 200’C: < 8% shrinkage force at 190’C: > 0.30 cN/tex, and the hot air shrinkage at 200’C (HAS 2O o) relating to the ultimate tensile strength (UTS) as follows: 20 HAS 200 < UTS - 67.

11. The high tenacity polyester yarn of claim 10, combining the following data: ultimate tensile strength: >70 cN/tex ultimate tensile strength extension: < 15% 25 reference extension (54 cN/tex): < 12% hot air shrinkage at 200’C: < 3% shrinkage force at 190’C: > 0.30 cN/tex.

12. The high tenacity polyester yarn of claim 10, combining the following data: 30 ultimate tensile strength: > 71 cN/tex ultimate tensile strength extension: <

13. % reference extension (54 cN/tex): < 10% hot air shrinkage at 200*C: < 4% shrinkage force at 190*C: > 0.75 cN/tex. - 26 13. The high tenacity polyester yarn of claim 10, combining the following data: ultimate tensile strength: > 74 cN/tex ultimate tensile strength extension: < 12% 5 reference extension (54 cN/tex): < 9% hot air shrinkage at 200°C: < 7% shrinkage force at 190“C: > 1.0 cN/tex.

14. The high tenacity polyester yarn of claim 10, combining the following data: 10 ultimate tensile strength: > 75 cN/tex ultimate tensile strength extension: < 10% reference extension (54 cN/tex): < 7% hot air shrinkage at 200*C: < 8%.

15. The high tenacity polyester yarn of claim 10, 15 combining the following data: ultimate tensile strength: > 73.5 cN/tex ultimate tensile strength extension: < 10% reference extension (54 cN/tex): < 7% hot air shrinkage at 200°C: < 6.5%. 20

16. A process for producing a yarn as claimed in claim 10, which comprises subjecting the as-spun yarn of claim 1, produced at a spinning takeoff speed above 2500 m/min, to single- or multiple-stage drawing at elevated temperature under a drawing tension between 25 20 and 33 cN/tex.

17. The process of claim 16, wherein the drawing tension is from 23 to 29 cN/tex. -2718. An as-spun yarn according to claim 1, substantially as hereinbefore described and exemplified.

18. 19. A process for producing an as-spun yarn according to claim 1, substantially as hereinbefore described and exemplified.

19. 20. An as-spun yarn according to claim 1, whenever produced by a process claimed in claim 9 or 19.

20. 21. A high tenacity polyester yarn according to claim 10, substantially as hereinbefore described and exemplified.

21. 22. A process for producing a high tenacity polyester yarn according to claim 10, substantially as hereinbefore described and exemplified.

22.

23. A high tenacity polyester yarn according to claim 10, whenever produced by a process claimed in any one of claims 16, 17 or 22.