DE1469122A1 - Process for improving the tensile strength of fibers, threads or foils made of polyureas - Google Patents

Description

P 14 69 122. 6 New «documents

S. I. DU PONT DE HSMOURS AND COMPANY 10th and Market Streets, Wilmington, Delaware 19898, v.St.A.

Process to improve the tensile strength of fibers, Threads or polion made from polyureas

The invention relates to a high tensile strength and a high modulus having shaped structures made of oriented, linear, completely synthetic, a "rigid chain" (βtiff-chain) containing polymers with a tensile strength of at least 9 g / den and an initial modulus of at least 180 g / den «

In recent years, the use of glass for the production of fibers has become increasingly important. Fiberglass are due to their high, i. H. la range of about 6.3 up to 6.9 g / the horizontal tensile strength, their high modulus, which is about 330 g / den «and your good waiting

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has been chosen for many purposes » Purely many purposes, such as use as ^ textile material, however, such fibers are unsuitable because of their relatively high density and brittleness. That's how it is Long-term flexural strength of glass fibers is known to be extremely low

Attempts have been made to produce completely synthetic fibers, which have a lower density than the glass fibers and a high flexural strength. However, searches have not proven to be completely successful because of the low density and high flexural strength only at the expense of one or more of the other desirable properties, such as travel strength, modulus and Heat resistance.

Surprisingly, it has now been found that, by suitable selection of a completely synthetic polymeric material and a simple treatment of the fibers made from it, a fiber material can be obtained which has all of the above-mentioned properties in combination. These new fibers not only have a module _s - which is in the glass fiber area, but also have a higher tear strength, excellent fatigue strength and a relatively low density «

The invention is accordingly directed to molded structures made of entirely synthetic polymers that have a high initial modulus in combination with a high tear strength

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strength, excellent flex life and low density. Another object of the invention is to provide a measure can be selected based on the polymers in which one can develop these highly desirable properties _o Another invention aims to develop transactions of a method for achieving this extraordinary self · ™. Further advantages and details of the purpose of the invention emerge from the following description »

The invention provides shaped, oriented structures made from linear, fully synthetic, rigid chain materials having a tensile strength of at least 9 g / denier and an initial modulus of at least 180 g / denier. The polymeric substances are selected from linear, orientable λ all-round synthetic, rigid-chain organic polymers, which have recurring units consisting of cyclic groups connected by functional links, a freezing temperature (T) of at least 180 ° C and a Young ¹ see module (E _u ) of at least 50 g / den. In a further embodiment of the invention, these new structures are produced ₉ by stretching the polymeric material at a temperature above the _{glass transition temperature and below its melting temperature 9} while it is in an essentially amorphous state.

For the purposes of the invention, the parameters E and T mentioned above are defined as follows: E "is the

Wg U,

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Young'ache modulus in g / den of Tollatändig reoriented polymer which is ο χ equal to 11.3, wherein the speed of sound ο in the polymer, measured in km / EEO at 26 ° C and represents from 30 to 70 i "relative humidity. For the polymers according to the invention, c is measured on a shaped structure from the pure, unoriented polymer by means of sound at a frequency of 10 KHz using pulses of 60 Hz duration. T is determined from graphs of E ^ versus T, usually at the main curvature point just below the crystallization temperature. The values of T measured in the manner described above essentially coincide with the values obtained in non-acuatic measurements, if the difference in the observational scale of the various detection methods is taken into account accordingly.

The expression “organic polymer ¹¹ includes all those linear, orientable, rigid chain, completely synthetic polymers with recurring units consisting of cyclic groups, which meet the above-described requirements for T and E _u . The particular structure of the cyclic groups or other groups that can be contained in the chain does not result in any restrictions. Only those polymers of the class described above which have rigid chains with strong interchain forces meet the requirements for a value of T of at least 180 ° C and of E of at least 50 g / the.

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When carrying out the invention, suitable polymeric substances can easily be selected from the class of polymers which have a glass transition temperature (T) of at least 180 ° and a Young's modulus (E _u ) of at least 50 g / den The stretching treatment can then be carried out using a conventional device, but must be carried out at a temperature at which the orientation rate significantly exceeds the rate of crystallization, i.e. the stretching must take place while the polymer is moving is in a substantially amorphous plastic state. This temperature lies in the range between the glass transition temperature (T) and the melting temperature of the polymeric material. A temperature must be selected at which the poly = ture can be oriented, and this temperature must therefore be below the decomposition temperature for those polymers which tend to decompose before melting.

The preferred stretching temperature for a particular material can easily be determined by determining the percent molecular orientation of the material stretched at different temperatures. The degree of orientation introduced by stretching the shaped article varies with the particular polymeric material used, but generally Has. In order to obtain the product according to the invention it has been found necessary that the molecular orientation be _{at least about 60 to 70 ° o}

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The following examples serve to further explain the invention without, however, characterizing it exhaustively. min bi is true. The values obtained are based on 3 to 20 filament sizes at a relative humidity of 65 ° and a temperature of 21 ° in order to obtain average properties. The flexural fatigue strength of the specimens is determined by passing 21 threads over a steel wire 0.076 mm in diameter, attaching one end of each thread to a clamp that can be rotated 180 ° around the main axis of the wire, and attaching a weight to each thread which corresponds to 0.6 g / den. A test cycle: each completed when the clamp is rotated 180 ° _{r as a} result the threads have been unwound from the wire and assume a position in which they hang freely from the clamp. Another test cycle is completed when the
The clamp is rotated 180 ° in the opposite direction, so that the threads are wrapped around the wire again

The flexural abrasion resistance of the threads is determined by applying a fiber layer with a total denier of 3500 den Fastened in a frame under a tension of 1.81 kg The threads are ge over a sapphire edge back and forth leads until complete failure occurs. The in di

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ipielen specified total number of cycles represents the ; el represents the values obtained on five samples prior to the occurrence of a hunted one.

i a ρ i e 1 1

g DiphenylenH ^ '- diisocyanate are in 1000 cm * 9thylformamide dissolved at 70 ° and in a large ing-Jiiecher entered. Set while stirring vigorously a solution of 112.2 g of 2,5-dimethylpiperazine in 1000 Dimethylformamide at 70 °. The polymerization sohrei · » on rapidly to form a clear, straw-colored gel; the temperature rises to about 90 °. One continues to stir inο The gelled solution is at 50 to 100 ° for some time in order to thermally reduce the polymer down to the molecular Doesn't decompose, which is a clear, gel-free. (which in the present case has an inherent diversity in dimethylformamide of 2.48). The solution will be centrifuged to remove bubbles and placed in a 60 ° old spin hopper.

Solution is at 122 ° through a 20-Looh spinning nozzle diameter 0.127 mm) at a temperature of 120 ° and a temperature of the nozzle holder

120 °, with the feed under a pressure of 14 at ; a speed of 8.76 cn; / min takes place. The t flows in at a temperature of 195 °, with the The laughing temperature is 190 ° at the head and 250 ° at the bottom.

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The thread bundle is at a spin draw factor of 4.0 withdrawn and is a uniform one, the shape of a elongated dog bone corresponding cross-section. Its as-spun properties are in Table I indicated.

Tabel Properties in the developed state Inherent Visooeität in Dimethylformamide 2.13 Tensile strength, g / den 2.7

Stretching, # 36

Initial modulus, g / den 52 Work rest at 3 #, £ 48

Tensile strength recovery at 5 #, $> 71

Young's module (E _u ), g / the 72nd Freezing temperature CTj, ⁰ C 250 The unoriented thread described above is over a

Plate stretched 1.8 times at 285 °. The drawn thread properties are given in Table II.

* · = ■ 8

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Table II Tear strength, g / den 9.9

Elongation » $> 5.2

Beginning module, g / den Molecular orientation +), #

+) The molecular orientation became acute, ale

certainly..

example

The thread material obtained in Example 1 is stretched in the following manner by methods which differ from the procedure described above.

3.1 m / min through a 35.6 cm long air bath of 325 ° µm

a) The thread is at an entry speed of 3.1 m / min through a 35.6 the 2.28faohe stretched.

b) The thread is fed through a 35.6 at an entry speed of 21 »3 m / min

stretched 2.28 times.

21a3 m / min through a 35.6 cm long air bath of 325 ° µm

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c) The thread is at an entry speed vr 9t1 m / min through a 35.6 cm long air bath at 308 ° that is 2.5 times as bad.

d) The thread is laid over a plate with a curvilinear Tt temperature profile of 50.1 cm length with an entry speed of 9.1 m / min and a Haximalplat * temperature of 320 ° stretched »

The properties of the threads obtained are in the tabc III stated.

Table III

attempt Ice cream,
κ / den Elongationι Initial module,
g / den a 9.4 4.8 278 b 9.5 6.3 243 C. 10.6 5.2 300 d 12.0 5.5 308 At a P i e 1 3

This example explains the influence of the stretching temperature on the end properties of the threads. A thread produced according to Example 1 (initial properties: with strength 1.9 g / den, elongation 35 $> and initial modulus 48 g / den) is used at different temperatures and others

¹⁰ "ORIGINAL INSPECTED

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Chen conditions (initial speed 9.1 m / min, rod length 50.8 cm, stretching ratio 2.6) stretched »a sheet with a curvilinear temperature profile is left behind. The properties of the threads obtained are given in Table IY.

Ta at le IV

Lmal plat- tensile strength- elongation, initial molecular temperature, speed, modulus, orientation, C g / den i » g / den $

295 7.8 4.2 256 90 305 7.6 4.0 274 84 325 8.1 4.2 253 93 335 10.0 5.0 262 90

i β ρ i el 4

test described above is at the same could factors, but by using a thread wieholt, the g /, an elongation of 36 f> and a Anfangsmovon 49 g / has the state in ereponnenen a Reiesfeetigkeit 2.5 denier. The results are given in Table V

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Ia lie lie

Maximum plat- Reissfeäßig- elongation, beginnings- molecular type temperature, speed, modulus, orientation,

° C g / den i> g / den $>

295 9.6 5.3 242 88 305 10.4 5.2 279 82 315 10.2 5.2 271 85 325 8.9 4.4 277 90 335 9.3 3.5 265 83

It gives elongation at different relative humidities no different results, since at these drawing temperatures any water associated with the thread passes through Evaporation is lost and cannot result in a softening of the polymer.

The threads produced according to this example prove to be against boiling and aging as well as against in intense electron irradiation stable. They have good short-term heat resistance, good dimensional stability even under load at elevated temperature, good Hot bass properties and satisfactory recovery properties. Their transversely measured properties are in Compared to the properties obtained when measured in the longitudinal direction, lower, but satisfactory in comparison with other synthetic threads and in comparison with glass surprisingly good.

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A comparison of the flexural fatigue strength and flexural abrasion resistance of the above threads with those of glass (the only material that gives a similar tensile strength behavior) the values obtained are surprising high. They show threads »- also unlike glass ~ one good moisture retention, that of silk and cotton is comparable.

The physical properties of the sample identified in Table V and stretched over a plate with a maximum temperature of 305 ° after boiling are in the table YI compiled.

Table VI

Tear strength at 21 °, g / den 10.4 Elongation at 21 °, # 5.2

Initial modulus at 21 °, g / the 279

Molecular orientation, i> 82 Travel strength at 21 °, wet, 6.8 g / den

Elongation at 21 °, wet, 96 3 »9

Initial modulus at 21 °, wet, g / den 265 Tear strength at 90 °, nose, g / den 4.1

Elongation at 90 °, wet, i> 3.2

Initial modulus at 90 °, wet, g / den 163

Work recovery at 3 # stretch, i> 48

Tensile strength recovery at y & elongation, # 76

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Table YI (port setting)

Flexural fatigue strength, cycles 3081 Sieve abrasion resistance, cycles 50

When the threads are exposed to a tempera for 48 hours! of 118 °, the heat resistance is reduced by 10 ° and the elongation by 6 °, the beginnings on the other hand slightly increased *

example

70.7 g (0.3 mol) of 3 ₉ 3 ^{t are dissolved}
phenylene together with 9 $ 8 g (0.6 mol) of triethylamine in methylene chloride, dilute this solution to 150 cnr, kt; bring it to 8 ° and place it in a large Waring mixer. A solution of 67.7 g (0.3 mol) of isophthaloyl chloride in 1500 cm ^{5 of} methylene chloride is further cooled to 12 ° with vigorous stirring Waring-Miec. The addition of the second solution all at once causes the temperature to rise to about 33 °. The polymer precipitates immediately and is obtained by trating; its inherent viscosity is 1, to 1.60 ES is suspended in water, heated to 100 °, filtered, washed with water and dried in a vacuum oven 110 °.

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g of the polymer thus obtained «earth in 1630 g

00 car) Dimethylaulfoxyd dissolved and centrifuged to remove sen au · The solution is fed into a spinning duct, the torrate container of which is a receptacle » Ages of 2 1 has. The storage container is set to 100 ° old. The solution is passed through a 15-hole spinning nozzle ^ diameter 0.127 ma) pressed out. The protrusion ' the nozzle is kept at 150 °; the cell temperature protrudes 255 °, the head temperature 140 °. At a spinning *

3k of 10.9 kg / cm becomes a uniform thread bundle wound at a speed of 94.2 »/ min; the cut of the single threads is dog-bone-like.

Spinning is continued for 3 3/4 hours without any increase in spinning pressure. The spun thread material is drawn out in distilled water for 60 hours, in order to remove the solvent, and then air-dried. It has a tensile strength of g / den, an elongation of 129 3 * and an initial modulus of 34 g / den. Its Young's modulus in the completely undetected state (E _u ) is 58 g / den and its injection temperature (?) 253 °. The thread material described above

1 over a 76.2 cm long plate (curvilinear temperature profile, peak temperature 340 ° and average » The temperature in the central zone 312 °) by 3, times 3draws, whereby the thread is mainly oriented rather than crystallized. That one small crystal! " it exhibiting thread material is then again over a

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50.8 cm long horizontal profile plate at 375 ° around the

Stretched 1.5 times to give it a very high crystallinity to be granted »When the ao treated thread is tested, the following results are obtained:

T a Ta e 1 1 e VII

Tear strength, g / den

Elongation, # 6.8

Beginning module, g / den 182

Friction strength, nose, at 21 °, g / den 7.4

Stretch, wet, at 21 °, $ 5.4

Initial modulus, wet, at 21 °, g / den 179

Tear strength at 75 °, g / den 6.2

Elongation at 75 °, $> 5.5

Initial modulus at 75 °, g / den 102

Tear strength at 225 °, g / den 4,?

Elongation at 225 °, 6.7 lbs

Initial modulus at 225 °, g / the 52

Tear strength at 300 °, g / den 2.6

Elongation at 300 °, $ 12

Initial modulus at 300 °, g / den. 33

Flexural fatigue strength at room temperature, cycles 1 330 000

Flexural fatigue strength at 140 °

in nitrogen, cycles 114,000

Recovery after boiling:

Work recovery at 3 # stretch, $> 48

Tensile recovery at $ 5> elongation, # 74

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The thread described above shows, apart from the high strength and rigidity, an extraordinary bending behavior ο It is not only very surprising that such a thread with a high modulus has a high resistance Shows bending tests, but it also proves to be far superior to most commercial textile fibers

Example 6

9 to 7 g of 2,5-dimethylpiperazine are dissolved in 270 cm 2 of dimethylacetamide which contains 5 g of lithium chloride per 100 cm. The solution is quickly stirred in an "Osterisser" and a solution of 21.37 g of 3.3 ^f -dimethyl-4.4 ^l -diisocyanate-diphenylene in 65 cnr of dimethyl acetamide, which ^{contains 5 5} g of lithium chloride per 100 cm, is added. 2 minutes after the start of the reaction, 0.46 g of 2,5-dimethylpiperazine in 15 cm ^{5 of} the abovementioned solvent is added, with stirring, in order to convert any excess xocyanate. The solution quickly becomes very viscous; it contains about 8 # solids and can be spun directly. A small portion of the solution is separated off, the solid components are precipitated by adding water, the polymer is dried and redissolved in concentrated sulfuric acid in order to determine the inherent viscosity, which is determined to be 2.56 ο

The solution is introduced into the storage container, which is heated to 52 °, of a device for dry spinning and is poured through

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a 10-Looh spinneret (hole diameter 0.127 mm) for one Pump pressure of 17 »6 at squeezed out, with the temperature of the spinneret 85 °> that of the inflowing air is 215 ° and the temperature of the shaft is 200 ° at all points « The yarn is with a spin draw factor of 2.1 with wound up at a speed of 98.8 m / min »Under under these conditions, the thread material retains sufficient solvent so that no finish has to be applied » However, the thread is then drawn out in cold water for 4 days to remove the dimethyl acetamide and lithium chloride to remove.

The thread material thus obtained (tensile strength 1.9 g / denier, elongation 48 #, initial modulus 59 g / denier, T 205 ° and Young's modulus 84 g / denier) is pre-stretched on a 30.5 cm long hot plate, its maximum temperature (near the center of the plate) is 351 ° and which has a temperature of 289 ° at the front end and 297 ° at the rear end. With an entry speed of 9.1 m / min and a take-up speed of 23.8 m / min, a draw ratio of 2.6 is obtained. The thread material develops a sonic modulus (of the oriented sample) of 551 g / den; its strength is 12.1 g / den, its elongation 3.3 $> and its initial tensile strength modulus 415 g / denο

Example 7

A thread sample produced according to Example 6 is over a hot rod stretched 3.3 times at 350 ° >

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After this stretching treatment, the thread material has the following properties:

Tabe lle VIII

Young's modulus, g / den 469

Tear strength, g / den 11.5

Elongation, # 3.7

Initial modulus, g / den 401

Example 6

This example shows the superiority of the invention Thread in the insert A manufactured according to Example 1 Thread A (tensile strength 2.4 g / denier, elongation 10 # and initial modulus 85 g / denier) is compared with a thread B, in which a tensile strength of 9 g / den, an elongation of 5 J »and an initial modulus of 280 g / den. The filaments are cut into 1.3 cm stacks by deposition from an aqueous slurry into sheets transferred and used as reinforcement in the manufacture of polyester resin panels The properties of the products used are given in Table IX »

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Table IX Fiber reinforcement, characteristic Tensile strength, kg / cm χ tO ^? Tensile modulus, kg / cm χ ΙΟ ⁵ Flexural strength, kg / cm ² 10 ³ Flexural modulus, kg / cm χ 10 *

Thread A Thread B 40 40 0.69 1.27 49 77 0.98 1.6 32 56

Table IX shows the excellent improvements made by developing the high quality properties in Reinforcement Bßweoken. How the table is eelgt the tensile strength and the modulus as well as the flexural strength and the flexural modulus almost doubled for the same percentages of fibers. The properties of the products reinforced with fiber B correspond to those of the Polyester resin with glass fibers can be obtained, which, however, result in poor weld line strength.

The following examples explain the critical importance of the limits of T_ and E _{u of} the synthetic polymers of which the products according to the invention are made.

Example 9

A linear polyamide is made from 2,5-Dimethylpiperaeln and Terephthaloylochloride produced by placing in a Waring

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Mixer at room temperature 10.6 g (0.1 Hol) sodium carbonate, 1.05% water, 45% of a 13.7 # aqueous 2,5-dimethylpiperazine solution (0.055 mol) and 50 cm · ⁵ methylene chloride Mixture with rapid stirring a solution of 10.15 g (0.05 Hol) of terephthaloyl ^{chloride in 50 cm 5 of} methylene chloride. The reaction mixture is poured into a glass beaker and the methylene chloride is evaporated from the mixture on a steam bath. The polymer is then isolated, washed and dried; the yield is 12 g, the inherent viscosity of the polymer in m-cresol (in 0.5 # solution) 1.53 · The polymer has a softening point above 400 ° and a glass transition temperature (T) of 292 ° · The polymer becomes _{dissolved in technical formic acid and shaped into solid fibers with a value of E u} equal to 27 g / den according to the technique of dry spinning from a solution with a solids content of 16 pounds.

The highest stretching ratio is obtained with the above thread at a stretching temperature of 450 °. The polymer can be stretched 4.4 times; the best physical properties achieved are a tensile strength of 7.7 g / denier, an elongation of 8 $> and an initial modulus of 150 g / denier. Since the present polymer does not meet the minimum requirement for E _n , the high resistance to ice and the high initial modulus cannot be achieved, although T also meets the requirement described above.

The following table contains a list of known grain

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Mercial polymers as well as other polymer measures, which _{further explain the critical importance of the values of T and E u} in the production of the products according to the invention. When using the process according to the invention, no structures with a tensile strength of at least 9 g / den and an initial modulus of at least 180 g / den can be obtained from the polymers given in the table.

Table polymer

Of course, schuk 6 nylon 66 nylon Polyacrylonitrile

Polyamide made from 2,5-dimethylpiperazine and terephthalic acid

Polyamide from bis (4-aminocyclohexyl) methane and terephthalic acid

Polyamide made from 2,5-dimethylpiperazine and adipic acid

Polyamide made from piperazine and hexahydroterephthalic acid

Polyethylene terephthalate

The following table XI lists a few in the inventions Polymers falling within the appropriate scope ο

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E _u > g / den -73 1-2 40 18th 50 21 73 25th 292 27 220 30th 90 36 > 300 41 68 24

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Table XI

Polymer

m-phenylenediamine and isophthalic acid 1,4-oyolohexane-dioxime and diphenylene-4,4 ^l -diocyanate

3 »3 * -Dimethy1-4,4 · -diamino-dlphenylene and isophthalic acid

Tetramethylpiperazine and 3 »3'-dimethyl-4» 4'-dieooyanate-diphenylene 2,5-dimethyl-N, N'-diaminopiperaein and isophthalic acid

2,5-dimethylpiperazine and diphenylene-4,4'-diisooyanate

2,5-dimethyl-N, N ^l -diaminoplperazine and dibeneoic acid

2,5-Dimethylpiperaein and 3 »3'-Dimethy1-4» 4 • -diieooyanat-diphenylen 2,5-diethylpiperein and phenylene-1,3-diisocyanate

A comparison of the above table with the polymers given in Table X shows the stark contrast in the Young's modulus of the unoriented polymers and in their glass transition temperatures.These polymers and a large number of similar polymers and copolymers with rigid polymer chains thus fall within the scope of the invention , d, a they have a freezing temperature above 180 ° and a value of E _u above 50 g / den ο

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E _u , g / den V ° 51 273 51 210 58 253 60 190 61 244 72 250 78 215 84 205 50 206

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The above examples illustrate the implementation of the invention without, however, characterizing it exhaustively; in the Rather, any of the changes described herein with respect to the fabric and the working conditions can be made to the lengths of the invention compared to the hare names used in the examples «

In the examples, the term "curvilinear temperature profile ¹ 'has been used. This external pressure denotes a temperature profile which is inconsistent along the plate over which the thread is stretched."

In the above examples it has been shown that a very high tensile strength in combination with a very high initial modulus can be developed in filaments made from a polymer having a rigid chain, the glass transition temperature (T ") being seen along with the Young's Module (E _y ) forms a measure for the choice of polymer. The method of developing these excellent properties has also been explained. Generally these fibers have a density below about 1.5 g / cm 'compared to about 2.5 g / onr in the case of Olas.

Depending on the polymer, the stretching conditions change within certain limits _o The stretching temperature used must, however, as described above, be within the limits of the range defined by the glass transition temperature and the melting point of the polymeric material o Furthermore

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85Γ

the stretching must take place before the crystallization of the Polymers occurs.

As the examples show, the maximum changes that vary with the type of polymer subject to stretching The stretching ratios that are achieved in the production of the threads according to the invention are comparatively low. A sufficiently high draw ratio is chosen to obtain full orientation.

The stretching can be carried out by passing the thread over or past a heated rod, heated roller, heated plate or the like. As the orientation and crystallization processes Require finite times, the fluctuating dwell times of the thread in the heated drawing zone of a Rod or plate seriously affects the thread properties influence; z. B. any stretching partial amount that could occur outside of the stretch point, in the Bar stretching is lost because the length of time the thread is under the stretching tension at an elevated temperature »is short. When stretching on plates the threads remain under the stretching tension at the stretching temperature for much longer

According to a preferred embodiment of the method according to the invention, the thread is stretched over a plate, which has a curvilinear temperature profile with a suitable apex temperature. As described above, the

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8treokung take place before the crystallization of the polymer occurs. When using a curvilinear temperature profiles, the Fadenteinperatur gradually approaches the maximum, which erlaufet an orientation of the molecular chains before the occurrence of a significant crystallization "However, you crystallinity is not a critical feature of the erfindungsgemäasen products, as well as non-crystallizing polymeric materials under the above parameter B _u and T fall "

From the description above, the reasons for which drawing on a plate may be preferable to develop maximum physical properties can be seen o However, bar drawing can also give excellent results if only a short dwell time of the thread at a certain optimal drawing temperature is required (cf. Example 7) "The advantages of the curvilinear temperature profile can, however, be achieved in bar stretching by using a number of individually heated bars to generate a similar temperature profile over the entire stretching area". but the achievement of a certain temperature profile with hot air requires a more complicated heating device

The critical properties of the polymers are the production of shaped articles with the ultimate strength in travel

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and rigidity of the products according to the invention have been clearly pointed out above. In addition to the polymers already listed, polymers and copolymers of other polyamides, polyureas, as well as polysulfonamides, polyesters, polyethers, polyurethanes, polyesteramides, polycarbodiimides, etc., in which the recurring units consist of cyclic groups linked by various functional members, can also be selected are that rigid-chained polymers with strong chain between forces provide _0. the cyclic groups may be carbocyclic or heterocyclic and the functional elements can be any of the usually high molecular weight polymers in terms occurring ο

Pie fibers and films according to the invention are not suitable only for most of the application purposes "for which so far Glass fibers were the only usable and available materials, but can also be used if one Fiber with lower. Density and higher flexural strength is required. The fibers according to the invention are suitable It is used to reinforce plastics, especially when the low weight of the body is important. Another important use is in protective clothing of the kind that have strength and stiffness as well Impact resistance are necessary. The many other uses include use in the form of mats, needled nonwovens, knitted, crocheted or woven fabrics, flat structures and covered ropes. Generally can the fibers according to the invention for the purposes of use are used where high strength, high

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resistance to deformation and good stability under load required are.,

All parts, proportions and! Percentages relate to » unless otherwise stated »on weight.

Numerous other changes are within the scope of the invention possible.

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Claims (1)

Q-412 / Q-55O August 8, 1968 Claim Process for improving the travel strength of fibers, threads or foils made of polyureas by stretching them at a temperature above the freezing temperature and below the melting temperature, characterized in that fibers, threads or foils made of polymeric ureas with a Young's modulus of at least 50 g / den and a glass transition temperature of at least 180 ° G, which is obtained by reacting 2,5-dimethylpiperazine with phenylene 1,5 ~ diisocyanate, diphenylene-4 »4 ^l -diisoeyanate or 3,3'-dimethylpiperazine 1-4 , 4 • -diieocyanatodiphenylene or by reacting tetramethylpiperazine with 3 ^ 3 ^l - ^> dimethyl-4,4 ^l -diisocyanatodiphenylene have been obtained α - 29 - 909814 / $ 112 ORIGINAL INSPECTS)