CH630937A5 - Polyester mouldings - Google Patents

Description

The invention further relates to a method for producing the shaped body in the form of a fiber.

DE-OS 2 520 819 describes a class of polyesters with 5 certain advantages over polyethylene terephthalate. These polyesters show optical anisotropy in the molten state, and they can be melt-spun into fibers which, in the heat treatment according to the processes described in DE-OS 2 520 820, have an increased toughness. It is proposed to use such heat-treated polyester fibers in tire cord and in other industrial and consumer products where high strength enables less yarn to be used, with the accompanying economic and other advantages. 15 In such end uses, especially truck tires, very high temperatures, e.g. B. above 150 ° C occur. It is therefore important that the cord yarn has high strength at room temperature and also high strength at elevated temperatures. The yarns produced from the 20 polyesters according to the invention meet these requirements.

The molded polyester body according to the invention is characterized by the features specified in claim 1.

In addition to units I and II, the new polyester of the molded body can contain up to 10 mol% (based on the total mol of the units) of other aromatic or cycloaliphatic units which form polyesters.

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(III)

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corresponds.

4. Shaped body according to claim 1, characterized in that it has a fiber shape.

5. Shaped body according to claim 1, characterized in that it has a film shape.

6. Shaped body according to claim 1, characterized. that it has the shape of a rod or a rod.

7. Shaped body in fiber form according to claim 4, characterized by a toughness of at least 18 g / den and an at least 65% retention of tensile strength at 150 ° C. 45

8. Shaped body in fiber form according to claim?, Characterized by an at least 70% retention of tensile strength at 150 ° C.

9. A process for producing the shaped body in the form of a fiber according to claim 4, characterized in that 50 is spun a melt of the polyester, the spun product is wound to form an oriented fiber and the fiber is heated in an inert atmosphere for a time sufficient to increase the toughness of the fiber.

55

The invention relates to moldings made from a new polyester, which in fiber form offers high toughness and high retention of tensile strength at elevated temperatures. The 60th

The fiber-forming polyesters are optically anisotropic in the melt. However, they can be spun in the melt and have an inherent viscosity of at least 0.7, determined according to the method described below. The fibers produced therefrom can be heat-treated to give fibers which have tenacity above 18 g / den and a retention of at least 65% of this tenacity at 150 °.

The invention is explained in more detail in the accompanying drawings. 1 shows the tenacity (g / den) versus temperature (° C.) for yarn according to the invention made of polyester (curve A) and for yarn from two comparison samples, namely the polymers of examples 2 and 3 (curve B and C) , applied. The comparative polymers are described in DT-OS 2 520 819. In Figure 2, toughness retention (%) versus temperature (° C) is plotted for the same set of polymers.

The polyester moldings can be produced or spun and the fibers can be increased in order to increase the toughness according to the general methods as described in DT-OSen 2520 819 and 2520820 and in particular in Examples 1 and 4 to 8 the heat to be treated.

The new polyesters can be produced from phenylhydroquinone and terephthalic acid or their functionally equivalent derivatives. If comonomer reaction participants are used, they can also be added or used as their functionally equivalent derivatives. Among such comonomers there can be mentioned: resorcinol, isophthalic acid, hydroquinone, p-hydroxybenzoic acid and 4,4'-dihydro-xydiphenyl, which give the following repeating units:

-0- <2>, Jt-py, -O-0-O -, - O-0-S- and-0- •

òs c = °

Mixtures of comonomers such as hydroquinone and resorcinol can also be used. The presence of the comonomer units lowers the melting point, which was expected, and facilitates the melt spinning treatment. In some cases, additional benefits such as filament abrasion resistance, filament adhesion to rubber are obtained. The fibers according to the invention, which are made from homopolymers, are of particular economic advantage compared to a copolymer, since fewer reactants are required to produce the homopolymer.

The terms “at least predominantly consisting of” or “containing essentially” have the meaning that all stated materials and conditions are very important in the implementation, but that unspecified materials and conditions are not excluded as long as they do not prevent the beneficial results of the present invention are obtained.

The melt polymerization, preferably under anhydrous conditions in an inert atmosphere, is used for the polymer synthesis. In general, the polymerization is continued until the polyester has a molecular weight sufficient for fiber production. Inherent viscosities of at least 0.7, which are determined as described below, are suitable for the production of moldings or moldings or pressed parts.

The new polyesters show an optical anisotropy in the molten state, determined according to the method described in DT-OS 2 520819. The polyesters have excellent thermal stability in the molten state, and they can be easily molded into fibers, films, rods or bars and other shaped articles or pressed articles. In the aforementioned DT-OSen 2 520819 and 2520 820, the heat-treated fibers according to the invention are not specifically mentioned, although they are included. However, the fibers according to the invention are surprising since they show both high strength and excellent strength retention at 150 ° C. The new, heat-treated polyester fibers according to the invention have tenacity of more than 18 g / den and retain at least 65%, more preferably at least 70%, of the tenacity at 150 ° C. Rods or rods made from the polymers according to the invention exhibit a high torsional modulus at elevated temperatures, and high heat deflection temperatures (heat deflection temperatures, determined according to ASTM D648 at 18.58 kg / cm 2 (264 psi) on a single, injection-molded rod).

The retention of toughness and moduli for fibers at elevated temperatures in the range of 100 to 200 ° C are in a number of reinforcement applications, e.g. B. in tires [R. E. Wilfong and J. Zimmermann,!. Applied Polymer Sei., 17, 2039-2051 (1973)], is important where heat accumulation or accumulation and high operating temperatures up to 150 ° C. frequently occur, in particular in the case of truck tires [FS Conant, Rubber Chem. And Technology, 44.397 -439 (1971) and P. Kainradl, G. Kaufmann and F. Schmidt, Kautschuk und Gummi-Kunststoffe, 19, 27-36 (1966)]. They are also important in other applications, such as clutch linings, brake linings, reinforcements for conveyor belts in glass production, ropes and cables in pump rods and suction pipes in oil wells. It is also important that the fibers have high toughness at elevated temperatures because the yarn toughness determines the amount of yarn required for truck tires or for reinforcements in other high temperature applications. The heat-treated fibers according to the invention are particularly useful for these purposes since they have a high retention of the tensile strength properties at elevated temperatures as well as high absolute

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Have tensile strength values at elevated temperatures.

Filaments of lower strength than specified were obtained. It is believed that careful and thorough mixing of the reactants during the polymerization is at least partially responsible for the better properties. The proportions and identity of the comonomers can also influence the properties. Other factors may be the purity of the components and the particular heat treatment conditions selected.

Manufacture of molded parts or bodies or pressed parts

For fiber production, the molten polymer mass, which is obtained either directly in the melt polymerization of the polymer-forming components or by melting the polymer, can be processed, e.g. B. by a melt spinning unit, and through a spinneret in a quenching atmosphere (z. B. held at room temperature air) and wound.

Fibers can be melt-spun in a manner known per se from spinnerets with a single hole or with many holes. In the melt spinning cell, the melt zone temperature can range from about 310 to about 370 ° C, depending on the sample. Higher temperatures are used for samples that have higher inherent viscosities or higher flow temperatures. Similarly, the spinneret temperatures can range from about 320 to about 375 ° C, depending on the melt zone temperature and melt viscosity of the polymer. Filter packs can be used in the spinneret assembly. The fibers can be spun in a wide speed range, preferably 100 m / min. up to 4500 m / min. The fibers spun in this way are oriented, with an orientation angle below 65 °, preferably below 25 °, determined as described in the present application.

Films can be produced by melt pressing or melt extrusion processes. Extremely tough rods or bars can be manufactured by injection molding. The relatively low viscosity of the melts is advantageous during processing.

In the heat treatment of yarns, it is often preferred to coat them with graphite or other inert materials, thereby avoiding sticking of the touching fibers.

Fiber samples as docks or strands or on spools can be heated in an inert atmosphere (e.g. nitrogen) under a variety of conditions. Heating usually takes about 30 minutes to 4 hours or longer at a maximum temperature that is close to, but below the filament melting point. Interfilament melting should be avoided so that the yarns can be wound up again. It is preferred that the maximum temperature be reached gradually or slowly continuously.

When winding the fiber samples on spools, it is preferred that there be a soft, resilient surface on the spool, e.g. B. a covering made of Fiberfrax® (a batted ceramic insulation from the Carborundum Company). The inert atmosphere within the furnace or other heat treatment chamber is changed during the treatment period by using a stream of inert gas e.g. Nitrogen, entering and leaving an oven sufficient to remove the by-products from the vicinity of the fibers.

As can be seen from the figures of the drawing, the heat-treated fiber of Example 1 (curve A), a fiber according to the invention, has a toughness which is high, i.e. H. which is greater at 150 ° C than that of the heat-treated fibers of Example 2 (curve B) or Example 3 (curve C), and shows a much lower loss of strength with increased

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Temperatures than the other fibers. Examples 7 and 8 (production according to the invention) show that the absolute value of the toughness at 150 ° C. is significantly higher than in the comparative samples (examples 2 and 3). It can be seen that the fibers of Examples 7 and 8 have a higher tenacity than that of Example 1, while the% retention of tensile strength is retained at a high value.

Measurements Inherent Viscosity

The inherent viscosity (r | inh) is defined by the following equation:

10th

rjinh =

In (nirel)

15

in the oil) the relative viscosity and C a concentration of 0.5 polymer in 100 ml of solvent. The relative viscosity (rjrel) is determined by diluting the flow time in a capillary viscometer of the dilute solution of the polymer by the flow time of the pure solvent. The diluted solutions used for the determination (r | rel) have the above-mentioned concentration (C); the flow times are determined at 30 ° C; the solvent is 1,1,1,3,3,3-hexafluoroisopropanol / chlorofrom (50/50, vol / vol).

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Tensile Properties The yarn tensile properties are determined using an "Instron" universal testing instrument (Instron Corporation, Canton Mass.), 30 which is equipped with an "Instron" environmental chamber system for tests at ambient temperature. The samples to be tested are conditioned for at least 1 hour at 21.1 ° C (70 ° F) and 65% relative humidity. The yarns are turned 3 turns / 2.5 cm (or as indicated)

flipped, Z turn, with 0.1 g / pull. Denier, den, is determined according to U.S. Patent No. 3,869,429. The same yarn denier is used in tests at ambient and higher temperatures to determine the retention property at elevated temperatures for a given fiber. The twisted or 40 twisted yarns are mounted with Instron 4C clips so that the gauge length of the yarn (distance between the clamps) is 10.0 ± 0.1 inches (25.4 ± 0.25 cm). The test at ambient temperature is carried out in a fiber conditioning environment. Testing at a higher temperature is done 45 by enclosing the yarn and clips in the environmental chamber, which is checked at the desired temperature. Such samples are kept in the chamber 3 minutes prior to testing. The test is carried out by stretching the yarn samples until they break at a constant rate of 50% / min, based on the standard fiber length. The stress-strain curve is automatically recorded by the "Instron" recorder and / or the stress / strain values are fed into a computer. From these values or from the stress-strain curve, the fracture toughness T is expressed as g / den, the elongation E as an increase in length to break, expressed as a percentage of the nominal standard length, and the initial modulus Mi as g / den of Inclination of a line drawn tangential to the initial linear part of the stress-strain curve is determined. These terms and their calculations are defined in ASTM D2101, part 25, 1968. Average values are calculated from two or more fractions.

Orientation angle OA ° (arc °) indicates the orientation angle and (20 Specific Are) as explained in US Pat. No. 3,671,542. They are determined using the method (2) described there.

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The invention thus relates to moldings made from the new polyester, preferably moldings in the form of fibers, films or foils or in the form of a shaped rod or rod, produced by injection molding or injection molding.

The invention further relates to a process for the production of the shaped body in the form of oriented fibers from the new polyester, in which a melt of the polyester is spun and wound up to form oriented fibers and in which the fibers are heated in an inert atmosphere for a period of time sufficient to increase their toughness.

The fibers of the new polyester which have been heat-treated according to the invention have a tenacity of at least 18 gI and have at least 65% retention of tensile strength at 150 ° C. They preferably have at least 70% retention of tensile strength at 150 ° C.

The invention is illustrated by the following examples. In the examples, the times specified for fiber heat treatment include both the time required to reach the specified temperature and the time the fibers are held at that temperature.

example 1

This example illustrates the manufacture of fibers from a poly (phenyl-1,4-phenylene terephthalate), i.e. it only contains

/ \\ - o- and ti

-C-

7 \ Vc-

Units in essentially equimolar amounts. These fibers show exceptionally high tensile strength retention at elevated temperatures.

54.0 g (0.2 mole) of phenylhydroquinone diacetate and 31.6 g (0.19 mole) of terephthalic acid are placed in a 250 ml three-necked round bottom flask equipped with a stirrer, a nitrogen inlet, a distillation head and a collecting container. The reaction vessel is evacuated three times and flushed with dry nitrogen. The reaction vessel is placed in a Wood metal bath at 290 ° C, stirring is started and then nitrogen flow is maintained. The bath temperature is increased to 300 ° C in about 13 minutes. After a further 27 minutes, the temperature of the bath is increased to 310 ° C, in a further 40 minutes to 320 ° C and in a further 35 minutes to 340 ° C. After a further 23 minutes, the nitrogen stream is shut off and the reaction system is placed in a vacuum, everything at 340 ° C. After a further 8 minutes, the pressure is reduced to about 10 mmHg. 2 min later, the vacuum is released with nitrogen, stirring is stopped and the molten polymer can cool under nitrogen. The yield is 56 g; t] inh = 1.03.

A plug made of this polymer is melt-spun in air through a spinneret with many holes [hole diameter of the spinneret = 0.023 cm, melting zone temperature (MZT) = 341-343 ° C, spinneret temperature = 346 ° C]. The resulting yarn is wound up at 457 m / min.

Three spools of yarn are collected and folded together to form a yarn of approximately 400 den, the T / E / Mi / = 3.4 / 0.9 / 408, O.A. = 14 ° (20.3 °).

Part of the plied yarn is wound on a bobbin covered with Fiber-Frax® (more than one layer) and treated in a nitrogen-purged oven under the following successive conditions; Room temperature -230 ° C / l, 5

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H; 230 to 275 ° C / 1.5 h; 275 to 295 ° C / 1.5 h; 295 to 312 ° C / 1.5 h; 312 to 325 ° C / 12.5 h. The bobbin can cool down and these yarn properties are observed at room temperature: T / E / Mi / den = 21.4 / 3.5 / 546/371. Portions of these yarns are determined for the tensile strength retention at elevated temperatures in accordance with the procedure previously described under the heading "Measurements". The following results are obtained.

Table I

Test temperature, ° C

Fracture toughness at the test temperature

% Retention of the original. Fracture toughness

21st

21.4

100

100

18.9

88

125

17.4

81

150

17.1

80

175

15.6

73

200

15.2

71

a yarn with T / E / Mi / den = 3.2 / 1.7 / 206/110 (determined on a yarn with three twists / 2.54 cm, Z direction). A sample of the layered yarn is wound on a bobbin coated with Fiber-Frax® and heat treated in an oven flushed with 5 nitrogen under these successive conditions: 170 ° C./1 h; Temperature increase to 230 ° C / l h; Temperature increase to 260 ° C / 2 h; Temperature increase to 290 ° C and held for 2% h. The coil can cool and these properties are observed at room temperature: T / E / Mi / den = 9.3 / 2.0 / 389/105. Portions of the heat treated yarns are tested for tensile strength retention at elevated temperatures as described in Example 1; the following results are obtained.

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Table III

Example 2 comparison

In this example it is explained that fibers made of copoly (chloro-1,4-phenylene terephthalate / 2,7-naphthalate) (70/30, mole basis) are worse than the fibers according to the invention in terms of retention of tensile strength at elevated temperature.

Copoly- (chloro-1,4-phenylene terephthalate / 2,6-naphthalate (70/30, mole basis) is prepared and spun into fibers by processes similar to those described in DT-OS 2 520 819. An as spun yarn with these properties: T / E / Mi / den = 7.0 / 1.8 / 533/499, determined on yarn with 3.6 turns / 2.54 cm, Z direction). A yarn sample collected on another bobbin during the same spinning process is wound on a bobbin covered with Fiber-Frax® and heat-treated in a nitrogen-purged oven under the following successive conditions: 220 ° C / lh; Temperature increase kept to 260 ° C / l h; Temperature increase to 285 ° C, held for 1 h; The temperature was raised to 300 ° C. in the course of 0.4 h and held for 12 h. The coil can cool down and these properties are obtained at room temperature: T / E / Mi / den = 34.9 / 4.7 / 597/419. Parts of the heat-treated yarn are tested for tensile strength retention at elevated temperatures, as in Example 1; the following results are obtained.

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Test temperature, ° C

Fracture toughness at the test temperature

% Retention of the original. Fracture toughness

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9.3

100

100

6.6

71

125

6.2

67

150

5.2

56

175

4.2

45

200

3.0

32

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Table II

Test temperature, ° C

Fracture toughness at the test temperature

% Retention of the original. Fracture toughness

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34.9

100

100

25.1

72

125

19.4

56

150

13.7

39

175

11.1

32

200

11.5

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Example 3 - Comparison In this example it is explained that fibers made of poly (chloro-1,4-phenylene hexahydro-terephthalate) are worse than the fibers according to the invention in terms of retention of tensile strength at elevated temperatures.

Poly (chloro-l, 4-phenylene hexahydro-terephthalate) is made from chlorohydrohinone diacetate and hexahydro-terephthalic acid and spun into fibers according to the procedures similar to those described in DT-OS 2 520 819. The as it is, spun yarn is layered six times, with one

Example 4

In this example it is illustrated that the substitution of 8.1 mol% units derived from p-hydroxybenzoic acid for part of the phenyl-1,4-phenylene-terephthalate units in poly- (phenyl-1 , 4-phenylene terephthalate) yarn with high tensile strength and high tensile strength retention at 150 ° C.

A mixture of 663 g (2.45 mol) of phenylhydroquinone diacetate (7 mol% excess), 381 g (2.29 mol) of terephthalic acid and 73 g (0.40 mol of p-acetoxybenzoic acid) is placed in a 21 resin flask , which is equipped with a sufficiently corrosion - resistant metal stirrer, a nitrogen inlet opening and a fractionation column with cooler and a variable removal head. The flask is flushed several times by evacuation and filling with nitrogen and then placed in a Wood metal bath at 195 ° C. The bath and the flask is heated to atmospheric then reduced pressure. The reaction mixture is stirred and the acetic acid reaction product is collected. The temperature of the reaction mixture is controlled by a thermocouple in the melt with a jacket. A nitrogen flow of 28.31 dmVmin is maintained and slowly reduced to zero how the boiler 50 is evacuated as the polymerization progresses, the following temperatures (° C) / past gene time (min) / pressure (mmHg) observed: 148/15/760; 274/26/760; 336/74/380; 341/76/250; 343/78/120; 343/80/50; 344/82 / 1-5; 348/93 / 1-5. After 93 minutes, the reaction mixture is cooled and the reaction vessel 55 is broken to release the polymer. This is then cut to a size such that it passes through a 0.32 cm (Ys inch mesh) screen. The polymer is then subjected to a cleaning process. It is won with 10. % aqueous (NH4) 2C03 solution washed and collected and then washed successively with distilled water, 10% aqueous acetic acid, water, acetone, refluxing acetone (with stirring), additional acetone and dried at 115 ° C and reduced pressure. The cleaning improves the spinning properties. The yield is 662 g (86%) of the polymer with r] inh of 2.12.

The polymer is dried again at 110 ° C. and reduced pressure for several hours and then placed in a simple 2.54 cm screw extruder and spon-

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nen, which is equipped with a pump block and a filter packing device and a spinneret with 100 holes, each hole has a diameter of 0.013 cm. The temperature in the screw feed zone is set so that the polymer melts (the maximum temperature in the 5 block is about 350 ° C.) and is fed uniformly into the spinneret (which is kept at about 345 ° C.) and with a throughput of 12. 4 g / min is extruded. The thread take-up rollers rotate at a surface speed of 220 m / min. The yarn is then passed through an air nozzle for consolidation and wound on a spool driven by a shaft, being careful to prevent mechanical damage to the yarn. The yarn shows a T / E / Mi / den of 6.1 / 1.6 / 400/496 (at 3.6 turns / 2.54 cm); N / A = 16 ° (20.1 °). 15

A circular strand of yarn is treated in an oven that is purged with nitrogen (with the exclusion of air) at these temperatures (° C) / time (h): gradually from 25 to 200 / 1.3; slowly from 200 to 308 / 4.0; 308/12, cooled from 308 to 25/20 1.3. The heat treated yarn shows a T / E / Mi / den of 24.8 / 4.3 / 485/486 (at 3.7 turns / 2.54 cm). At 150 ° C it shows a T / E / Mi / den of 18.9 / 3.8 / 335/487. The retention of toughness is 76%. A certain degree of adherence is observed between the individual filaments.

Example 5

This example illustrates that the substitution of 2.5 mol% units derived from resorcinol for a portion of the units derived from phenylhydroquinone in poly (phenyl-1,4-phenylene terephthalate) Yarn with high tensile strength and high tensile strength retention at 150 ° C results.

This polymer is prepared essentially according to the procedure of Example 4 from 741 g (2.74 mol) of phenylhydroquinone diacetate, 28 g (0.14 mol) of resorcinol diacetate and 448 g (2.70 mol) of terephthalic acid, whereby 784 g (93% product with Y | inh 1.54. The total polymerization time is 76 min, of which 16 min take place under reduced pressure and 338 to 341 ° C.

This and a similar preparation (i] in = 1.66) of extracted, washed and dried polymer is physically mixed, dried and then spun in the extruder of Example 4 under similar conditions; Spinneret temperature = 335 ° C. The yarn has a T / E / Mi / den of 6.3 / 1.7 / 434/531.

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A strand of this yarn is heat treated as described in Example 4 at these temperatures (° C) / times (h): 25-200 / 2; 200-312 / 5; 312 / 6.7; 312-25 / 2.7. The heat treated yarn shows a T / E / Mi / den of 29.7 / 4.4 / 559/506. At 150 ° C shows a T / E / Mi / den of 22.9 / 3.8 / 392/510.

Example 6

This example illustrates the manufacture of high tensile strength and high tensile retention yarn at 150 ° C from a copolymer of poly (phenyl-1,4-phenylene terephthalate) in which 5 mole percent of the units differing from terephthalate. derive thalic acid, are replaced by units derived from trans-hexahydroterephthalic acid.

This polymer is prepared essentially according to the procedure of Example 4 from 790 g (2.89 moles) of phenyl hydroquinone diacetate, 426 g (2.56 moles) of terephthalic acid and 23.2 g (0.135 moles) of trans-hexahydroterephthalic acid. The polymerization is carried out for 66 minutes, of which 18 minutes at 334 to 344 ° C. and reduced pressure. The yield is 790 g (93%) of polymer with r] inh of 1.76.

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The polymer is dried and then spun in the extruder of Example 4 under similar conditions. The yarn shows a T / E / Mi / den of 6.3 / 1.6 / 420/493 (3.6 turns / 2.54 cm ), OA 16 ° (20.1 °).

A skein of this yarn is heat treated as in Example 5. The heat treated yarn shows a T / E / Mi / den of 23.0 / 3.4 / 602/483. At 150 ° C it shows a T / E / Mi / den of 16.8 / 3.0 / 335/489.

Example 7

In this example, the production of poly (phenyl-1,4-phenylene terephthalate) yarn of high tenacity and high tenacity retention at 150 ° C from phenylhydroquinone and terephthalic acid is illustrated.

545 g (2.93 mol-3 mol% excess) of phenylhydroquinone, 471.4 g (2.84 mol ) Terephthalic acid and 0.01 g titanium tetramethylate in 90 ml cyclic tetramethylene sulfone (helps to return the monomers and oligomers to the polymerization). The heated column and domed lid help separate the monomers, especially the phenyl hydroquinone, from the water reaction product. The reaction is carried out with nitrogen purge in a similar manner as in Example 4 at the following temperatures (° C) / times (min) / pressures (mmHg): 220/12/760; 276/32/760; 324/60/760; 326/85/630; 324/100/510; 329/115/380; 332/130/250; 336/145/120; 338/160 / - 5; 336/184/2; 338/228/2; 340/247/2. After 255 min, the reaction mixture is cooled, the polymer is isolated, cut into small pieces and extracted essentially as in Example 4. The yield is 591 g (66%) of polymer with r) inh of 1.61.

The polymer is dried and then spun as in Example 4. The spinneret temperature is 354 ° C, the throughput is 8.7 g / min. The yarn is collected at 165 m / min and shows a T / E / Mi / den of 5.6 / 1.5 / 428/511 (3.6 turns / 2.54 cm); O.A = 17 ° (20.1 °)

A strand of yarn is heat treated as in Example 4 at the following temperatures (° C) / times (h): 25-220 / 1.3; 200-316 / 10; 316/6; 316-25 / 1.3. The heat treated yarn shows a T / E / Mi / den of 22.3 / 3.6 / 573/490 (3.6 turns / 2.5 cm). At 150 ° C it shows a T / E / Mi / den of 18.2 / 3.3 / 394/488.

Example 8

This example explains the production of poly (phenyl-1,4-phenylene terephthalate) fibers with exceptionally high toughness values at 150 ° C.

This polymer is essentially prepared according to the expiration of Example 4 from 780 g (2.89 mol) of phenylhydroquinone diacetate and 448 g (2.70 mol) of terephthalic acid, 760 g (89%) of products having a content of 1 , 8 receives. The total polymerization time is 90 minutes, including 20 minutes under reduced pressure and 343 to 366 ° C. The polymer is isolated, ground and purified by passing a stream of heated nitrogen (250 ° C) up through the finely divided polymer in a column during 2 h directs.

These and four similar preparations are physically mixed, dried, pelletized, then essentially as described in Example 4, but spun through a 70- or 65-hole spinneret. The throughput is 9.9 g / min; the speed of the pickup roller is 256 m / min. The oriented yarn shows a T / E / Mi / den of 5.8 / 1.3 / 473/342 (4.4 turns / 2.54 cm).

A skein of yarn is heat treated as described in Example 4 at the following temperatures (° C) / times (h): 25-200 / 2; 200-317 / 10.7; 317 / 3.3; 317-25 / 2. The warmth7 630 937

traded yarn shows a T / E / Mi / den of 28.4 / 3.4 / 710/335 (4.4 turns / 2.54 cm). At 150 ° C it shows a T / E / Mi / den of 21.5 / 3.2 / 421/347.

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1 sheet of drawings

Claims (3)

630 937 PATENT CLAIMS 1. Polyester molded article, characterized in that the polyester consists at least for the most part of repeating units of the formulas (I) and (II) (II) exists and has a fiber-forming molecular weight. 2. Shaped body according to claim 1, characterized in that the polyester in addition to the units of the formulas (I) and (II) contains up to 10 mol% of other aromatic or cycloaliphatic polyester-forming units. 3. Shaped body according to claim 2, characterized. that the other aromatic, polyester-forming unit of the formula (III)