DK153800B - PROCEDURE FOR MAKING POLYAMIDE FIBERS AND POLYAMIDE MOVIES WITH HIGH TENSION STRENGTH AND EXTENSION EXTENSION OF 3.5% - Google Patents

Description

DK 153800B

island

The invention relates to a process for the production of polyamide fibers or films which at the same time exhibit a tensile strength of at least 18 g per square meter. denier, a fracture elongation of at least 3.5% and crystalline regions with a primary, 5 apparent crystallite size, measured as specified below, of less than 52 angstroms, by extrusion of a spinning solution through an aperture over a gap in the form of a layer of inert , non-coagulant liquid or gas into a coagulation bath.

US Patent No. 3,414,645 discloses a wet spinning process with a dry spinning nozzle in which a solution of exclusively aromatic polyamides in an amide such as Ν, Ν-dimethylacetamide is extruded over an air gap into a coagulation bath and then stretched, washed, dried and dried. 15 are stretched to filaments.

German Publication No. 1,810,426 discloses the use of certain optically anisotropic spinning solutions of carbocyclic aromatic polyamides by a wet-spinning method to produce fibers of good strength in the fresh-spun state, i.e. without stretching or heat treatment. While high temperature stretching increases tensile strength, heating can adversely affect certain fiber properties for many applications. Heating causes an increase in crystallinity, which is generally accompanied by greater brittleness and less fracture elongation. Such fibers are of lesser value for various applications, such as reinforcing yarns or cords for embedding in tires and belts.

The polyamide fibers and films prepared by the process of the invention are obtained by extrusion of highly concentrated, highly acidic solutions of certain aromatic polyamides over an air gap or through a layer of a non-coagulant liquid such as toluene into a coagulation bath.

The aromatic polyamides used in the process have straight, rigid polymer chains which, due to

^ DK 153800B

ISLAND

2 in their rod-like nature, when present in highly concentrated solutions, have been found to render the polymer optically anisotropic, i.e. that they depolarize plane polarized light. These anisotropic solutions are nematic (thread-like), the anisotropy being one-dimensional. The anisotropy is due to the fact that the rod-like polyamide molecules tend to unite in bundles in local areas in these rather concentrated solutions. That association has been proven to be retained by air gap spinning, thus providing direct fibers of high strength without stretch orientation.

However, only certain para-oriented aromatic polyamides have shown the ability to provide such anisotropic spinning solutions, and even if a polymer of this type is selected, other requirements must also be met. A suitable solvent must be selected and the polymer concentration must be extremely high to provide anisotropy. Precisely this latter presents particular difficulties because a solution immediately before it becomes anisotropic usually exhibits such a high viscosity that the solution 20 can hardly be stirred.

Given the high viscosity, one skilled in the art would hardly consider the addition of additional polymer as desirable. However, it has now surprisingly been found that a decrease in viscosity often occurs when additional polymers are added. Thus, since very anisotropic spinning solutions are desired, particularly high polymer concentrations are obtained, which are obtained only with certain acid solvents, and the spinning must be carried out through a layer of inert, non-coagulant medium.

The fibers or films made by the process of the invention preferably have a structurally solid, radial orientation which is not detected by any of the known fibers made of the same polymer. The presence of radial orientation occurs when the fibers or films have a lateral crystallite order (LKO) of at least 10, 3

ISLAND

. DK 153800 B

in '5 ·' with an LKO value of 10 or greater signifies significant radial orientation. In radial orientation, the planes of the benzene rings in the polymer chains are assumed to be oriented radially, i.e. according to the radius of the fiber.

Furthermore, the fibers produced by the method of the invention have a combination of tensile strength and elongation that are not exhibited by any known fibers.

Fibers with a fracture elongation greater than 3.5% are known, but only in combination with tensile strengths well below 18 gpd. On the other hand, fibers with a tensile strength of at least 18 gpd are known, but only in combination with fracture extensions of less than 3.5%.

However, a break elongation of more than 3.5% is required for fibers to be used for cover orders and, of course, the tensile strength must be as high as possible.

Some filaments according to German Publication Nos. 1 810 426 and 1 929 694 have tensile strengths and logarithmic viscosity figures as stated herein. However, none of these filaments has an LKO value of at least 10, and none of the filaments with a tensile strength of at least 18 gpd have a fracture elongation of at least 3.5% or an apparent crystallite size of less than 52 Å. Examples 12 and 24 of German Publication No. 1 810 426 show e.g. fracture extensions of only 2.0% and 3.2%, respectively, when the tensile strength is greater than 18 gpd. The same goes for the filaments in German Publication No. 1 929 694.

Furthermore, it is known to spin at least some polyamides having a logarithmic viscosity number greater than 2.0 dl / g at a concentration of at least 30 g / 100 ml of solvent. However, the known spinning is a conventional wet spinning which suffers from the usual shortcomings thereof. German. Publication No. 1,810,426 does not relate to air gap spinning, and the logarithmic viscosity of the polyamides is too low like the solvent used, and the polymer concentration. In addition, the tensile strength of these known fibers is low.

Air gap spinning of aromatic polyamides is quite

DK 153800B

4

ISLAND

disclosed in U.S. Patent No. 3,414,6457, however, a considerable number of selections must be made from this United States Patent before reaching the present invention.

5 First, choose the right polymer. Only one polyamide among those mentioned in United States Patent No. 3,414,645, namely poly (4,4'-benzanilidylene-terephthalamide), fulfills the requirements set forth here in a structural sense. However, one of ordinary skill in the art has no urge at all to select just this particular polyamide for the spinning, as it is clear from the United States patent that fibers made by the process of this patent have only fairly ordinary properties (about 6-7 g per denier ) which is no better than the properties obtained by dry spinning of similar polyamides, e.g. poly (m-phenylene isophthalamide). Thus, one skilled in the art would not expect that poly (4,41-benzanilidylene-terephthalamide) fibers were in any way superior to all other fibers. Of course, even if the latter compound was used for the spinning, in order to dissolve this polyamide, one of the solvents clearly preferred by the method of U.S. Patent No. 3,414,645, namely an amide, had to be employed. Hereby, however, one will not be able to prepare a suitable solution due to the low solubility shown by poly (4,4'-benzanilidylene terephthalamide) herein.

This connection will e.g. do not form solution in N, N - dimethylacetamide containing 6.5% lithium chloride, even at a concentration of only 9.3%. If one skilled in the art tried to use sulfuric acid as a solvent for poly (4,4'-30-benzanilidylene terephthalamide), he would not get filaments both with high breaking strength and with a breaking elongation of at least 3.5% unless the polyamide had sufficient high logarithmic viscosity number, and the solution had a sufficiently high concentration (at least 14% by weight in sulfuric acid. However, one skilled in the art would hardly attempt to prepare a

ISLAND

5

DK 153800B

solution with a polyamide concentration greater than 14% in sulfuric acid, as experiments show that such solutions are solid, at least at room temperature, which is the one most commonly used in technical plants.

U.S. Patent No. 3,414,645 does not indicate that all of these selections necessary to arrive at the present invention would be advantageous in any way.

The usual concentration of spinning the 10 meta-oriented aromatic polyamides according to the examples of US Patent No. 3,414,645 from amide solutions is 10-30% by weight. According to Table I, the preferred polymer concentration in these amide solvents is 15-22 wt%. However, the usual concentration of spinning para-oriented aromatic polyamides from amide solutions is much lower, especially in the case of high molecular weight polymers.

The concentration of 10-30 wt% polymer, on the other hand, relates to the Ν, Ν-dimethylacetamide solutions, which are those actually used in the examples in the United States patent. Although 20 sulfuric acid is proposed as an alternative solvent, one skilled in the art would have no particular incentive to choose this instead of Ν, Ν-dimethylacetamide, which is used in the U.S. Patent Examples because he would only expect to obtain the same results with both types of 25 solvents and because sulfuric acid is much more difficult to use industrially.

Thus, those skilled in the art who have many possible spinning methods at their disposal would have no particular reason for choosing precisely the method of U.S. Patent No. 3,414,645 and then for applying it to another and very special group of polymers in special solvents by a particular concentration so as to solve a completely different problem, namely the provision of very high strength filaments, especially for use as tire reinforcement. The filaments produced in accordance with the United States Patent Specification have by extension 6

DK 153800B

ISLAND

only ordinary properties that are about the same as obtained by dry spinning, and US Pat.

3,414,645 does not indicate that filaments of particularly high tensile strength can be obtained by modifying the known method of polymer, solvent and polymer concentration.

In contrast, the polyamide fibers or polyamide films obtained by the process according to the invention have an unusually high tensile strength in comparison with known fibers and films of the same polymer types. It is the process of making these polyamide fibers or polyamide films that condition these properties.

The fibers and films in question can only be obtained from certain specific polyamides with straight, rod-like polymer chains. These polyamides have the ability to form anisotropic spinning solutions, which behave like liquid crystals because the rod-like molecules are linked to each other in bundles within local areas of the spinning solution. Precisely the use of polymers constructed with certain divalent radicals ensures that they are straight, rod-like polymer chains whose rod-like nature will not be disturbed if two otherwise rigid radicals with elongated bonds are joined by azo or azoxy groups between the amide groups.

The azo and azoxy groups are also even and rigid. The properties of the present fibers or films are based more on the straight, rod-like nature of the polyamides rather than on the particular polyamide composition used.

Accordingly, the process of the invention is characterized in that as a spinning solution 30 a polyamide consisting mainly of repeating units is selected from the following:

0 0 HH

-C-R "C- (I) -N-R'-N- (II)"

ISLAND

7 DK 153800B

O H

and -CR "-N- (III) where the units I and II, where they occur, are mainly 5 in equimolar amounts and where for at least 95 mol% of the total R, R 'and R" groups, which may be the same or different, R 'is selected from 1,4-phenylene optionally substituted with a methyl group or chlorine atom, and 4,4'-biphenylene, R "is 1,4-phenylene, and R is as defined 1Q for R 'as well as transvinylene, trans-1,4-cyclohexylene, 1,5-naphthylene and 2,5-pyridylene, wherein the 1,4-phenylene groups may be mutually linked to an azo group and n is 0 or 1, dissolved in sulfuric acid, the concentration of which is at least 98%, chlorosulfonic acid, fluorosulfonic acid or mixtures thereof to a polyamide concentration (C) of at least 30 g per 100 ml of solvent, the logarithmic viscosity number of the starting polyamide being at least 2, 8 dl / g measured at 30 ° C and a concentration of 0.5 g polymer per

100 ml of solvent in concentrated sulfuric acid.

The most preferred fibers and films have an LKO of at least 10 and are automatically obtained by the process when at least 75% of the R groups are 1,4-phenylene and at most 25 mole% of all groups of Formulas I, II and III are groups of formula III.

The most preferred spinning solutions, e.g. poly-25 (p-phenylene terephthalamide) solutions are solid at room temperature and must be heated to spin. It has thus been found in practice that a suitable range for the extrusion is temperatures from 40 up to 120 ° C. Above 120 ° C, the anisotropic nature of these solutions is destroyed. The 30 best fiber properties are obtained at the highest polymer concentrations, e.g. 40-56 g / 100 ml solvent. A preferred extrusion temperature range is 70-90 ° C, which provides the best treatment conditions while preserving anisotropy.

35 The best fiber properties are obtained using

ISLAND

8

DK 153800B

lyamides having the highest logarithmic viscosity numbers, preferably at least 3.0, especially at least 4.0, and most preferably 4.5 dl / g. The fibers or film preferably have an LKO value of at least 20.

The fibers and films produced by the process of the invention are characterized by an exceptionally high tensile strength in combination with moderate fracture extensions, which give high toughness at low to moderate degree of crystallinity as indicated by the apparent crystallite size.

The fibers and films thereby have fracture extensions of at least 3.5%, preferably 4.5%, and their tensile strength is at the same time from 18 to 32 g per minute. denier or even higher. Typically, the fracture elongation is from 3.5 to 7% and the fracture toughness 15 can be from 0.40 to 1.5 gpd or even higher and the initial modulus can be from 300 to 800 gpd or even higher.

Fibers with a modulus of at least 400 are preferred. The fibers have orientation angles of from approx. 30 ° to 12 °.

To further illustrate the invention, the drawing serves to illustrate - FIG. 1 schematically shows an apparatus for carrying out the method according to the invention for making fibers; FIG. 2 shows a cross section of such a fiber; FIG. 3, 4, 5 and 6 are graphical representations of electron diffraction patterns determined in selected areas of this cross-section, where the sections shown by dashed arcs have the lowest photographic density, while the fully drawn arcs are reproduced such that the stroke thickness is proportional to the photographic density, FIG. 7 and 10 are drawings of a densitometer trace of whole and half diffraction patterns, respectively; and FIGS. 8 and 9 are drawings of part of a densitometer trace.

In FIG. 1, a spinning solution is pumped through a transport line 51 through a spinning head 52, through the openings Ο L, DK 153800 B.

9 in a spinning nozzle 53 through a layer of liquid or gas 55 and down into a coagulation bath 56 in a spinning tube 60 through which the filaments 54 delivered from the nozzle 53 are passed. Even in the fresh-spun condition, these filaments are strong enough to pass as a multifilament bundle 65 under a conductor 57 and are wound directly onto a rotating spool 59. The coagulation fluid in the bath 56 contained in a container 61 is entrained through the spinner tube 60 and falls down into a container 62 from which it is led back by a pump 63 and a tube 64 to the container 61.

Polyamide fibers or polyamide films will in the fresh-spun condition prepared by the process of the invention from copolyamides, i.e. wherein R and R 'are a mixture of at least two different groups or, when units I, II and III are found, have an extension of at least 4.5%, while products made from homopolyamide will have an extension of at least 3%.

At least 95 mole% of R, R 'and R "together are selected as above from trans-1,4-cyclohexylene, 1,4-phenylene, 1,5-naphthylene, 2,6-naphthylene 2, 2,5-pyridylene 4,4'-biphenylene "- <O> - and trans-vinylene, wherein the 1,4-phenylene groups may be linked to an azo group.

Furthermore, the 1,4-phenylene group may be substituted by a methyl group or chlorine which is non-reactive (e.g., thermal) upon subsequent processing of the polymer, e.g. heat treatment of a shaped article of the polymer.

Such reactivity is undesirable as it can cause branching and crosslinking and may adversely affect the spinning and / or fiber properties.

The chains of the linear condensation polymers used in the process of the invention may comprise up to approx. 5% (on a molar basis) of groups not falling 0 10

DK 153800B

in accordance with the above-mentioned regulation, ie. that they do not have elongated bonds or are not rigid.

It will be appreciated that these non-conforming groups vary in their influence on the properties of the fresh-spun products. Thus, rigid groups, such as m-phenylene, whose chain-extending bonds are neither coaxial nor parallel and oppositely directed, and very flexible groups such as hexamethylene and decamethylene will usually be used in small amounts, while groups such as 4,4'-10-biphenylene , can be used in larger amounts of up to 5% to form fibers which still have the usual combination of properties. Although not preferred, a small amount of the amide units in the linear condensation polymer chain can be replaced, if desired, with other stable non-amide forming units, for example, ester forming units or urea or sulfonamide forming units. Usually, such products are more difficult to manufacture and have a more limited use.

The polymer to be spun may be a homopolymer, a random copolymer, an ordered copolymer or mixtures of homopolymer and / or copolymers as described above. Conventional additives such as dyes, fillers, matting agents, UV stabilizers and antioxidants can be incorporated into the fibers and films of this invention.

Preferred polyamides include: poly (p-phenylene terephthalamide) hereafter (PPD-T), poly (p-phenylene-ρ, ρ1 - biphenyl dicarboxamide), poly (p-phenylene-1,5-naphthalene di carboxamide), poly (trans-1,4-cinnamamide), copoly (p-phenylene-4,4'-azoxybenzene dicarboxamide / terephthalamide), poly (p-phenylene-4,4'-trans-stilbene dicarboxamide) and poly (p-phenylene-acetylenedicarboxamide).

The polymers to be used in the process of the invention are conveniently prepared by reacting suitable monomers in the presence of a low temperature technique of the amide type solvent as described in U.S. Pat.

DK 153800 B

11 o Tent No. 3,063,966. To obtain high molecular weight polymers, the monomers and the solvent should contain a minimum of impurities and the water content of the total reaction mixture should be less than 0.03% by weight.

Poly (p-phenylene terephthamide) is conveniently prepared by dissolving 1728 parts of p-phenylenediamine in a mixture of 15,200 parts of hexamethylphosphoramide and 30,400 parts of N - methylpyrrolidone, cooling to 15 ° C in a polymerization boiler covered with nitrogen, to which 3243 parts are added. powdered terephthaloyl chloride with rapid stirring. The solution forms gel and transforms into a dry crumbly material over 3 to 4 minutes. Stirring is continued for 1 1/2 hours, if possible under cooling to keep the product temperature at approx. 25 ° C. The polymerization is mainly quantitative, and the final reaction mixture contains 7.5% polymer with a logarithmic viscosity number of approx. 5.5 dl / g.

The logarithmic viscosity number of the polymer from this system can be controlled by the ratio of monomer to solvent. A reduction in the amount of monomer 20 from over 9.83% to 8.64% gives a reaction mixture containing 6.5% polymer with a logarithmic viscosity number of 6.0 dl / g. The use of approx. 11.7% monomer gives a reaction mixture of 9.0% polymer with a logarithmic viscosity number of 2.5 dl / g.

The crumbly acidic product is stirred vigorously or ground with water in a Waring mixer or a colloid mill and the resulting polymer slurry is filtered. The wet polymer is further washed by resuspending with soft water to remove solvent and HCl and collecting on a filter. The solution and filtration are repeated approx. fine times in a row followed by a final wash with distilled water.

To aid in the neutralization, one of the soft water wash containers may also contain sodium carbonate or sodium hydroxide. The polymer is then dried at 120-140 ° C.

The polymerizations may also be carried out by means of

ISLAND

12

DK 153800B

continuous mixing of the monomers.

Suitable solvents are sulfuric acid with a concentration of at least 98%, chlorosulfonic acid, fluorosulfonic acid and mixtures of these acids. The sulfuric acid may have a concentration above 100%, ie. fuming sulfuric acid. A sulfuric acid with a concentration of approx. 99.8% is preferred. Higher concentrations may be used, but the presence of excess sulfur trioxide tends to degrade the polymer, thereby reducing the logarithmic viscosity number. This can cause a loss of filament tensile strength. The degradation is time- and temperature-dependent, so that the time if fuming sulfuric acid in which the polymer is exposed to elevated temperatures should be kept to a minimum. The definition of suitable solvents does not preclude the presence of certain additives. Thus, hydrogen fluoric acid, halogenated alkyl sulfonic acids, halogenated aromatic sulfonic acids, halogenated acetic acids, halogenated lower alcohols and halogenated cations or aldehydes can usually be found in amounts up to about 20%. 30% of the total weight of the solvent and additives. The exact amount of additive that may be present depends, of course, on the particular solution-polymer combination used. The use of fluorosulfonic acid (rather than sulfuric acid) or lower polymer concentrations allows the use of larger amounts of an additive. The greater the percentage of halogen present in the additive, the greater is usually the amount of additive that can be used up to the phase separation limit. Trifluoromethanesulfonic acid can usually be present in an amount equal to the weight of the above sulfuric acids. In addition, sulfones, chlorinated phenols and nitrobenzenes can be used as solution additives in a smaller amount than the halogenated additives described above.

The water content of the spinning fluid should be checked for

DK 153800 B

ISLAND

nice to be less than 2%. Excess water can interfere with the formation of spinning solutions suitable for spinning and can also lead to unusually large degradation of the polymer. The relatively anhydrous polymer 5 (preferably less than 1% water) should be mixed with an anhydrous solvent under conditions which expose the polymer as little as possible to the effect of atmospheric humidity and the spinning solution should be stored under a dry atmosphere.

The spinning solutions should be mixed and kept during the spinning process at the lowest temperature at which it is possible to keep them liquid to reduce the degradation of the polymer resulting in lower values of the logarithmic viscosity number. The time that the spinning solutions are exposed to temperatures above 90 ° C should be made as short as possible.

A particularly suitable method is to continuously prepare the spinning solution and feed it directly to the spinning nozzle, with any residence time, e.g. in reservoir or tank, make as little as possible. If the process is carried out in batches and the spinning solutions are to be stored for later use, they can be frozen in solid form, especially under a dry nitrogen cover. Such a densified spinning solution can be ground into granules or powders and then used as feed material for a screw extruder and then passed to a spinning nozzle.

Here, the concentration (C) of the spinning solution is defined as grams of polymer per minute. 100 ml of solvent at 25 ° C. By "solvent" is meant the sulfuric acid in question plus any solvent additive present.

At least 30 g, but more than 40 g of polymer per 100 ml of solvent is used. When the solvent is sulfuric acid containing approx. 98 to approx. 100% H 2 SO 4, this corresponds to spinning solutions containing at least 14, preferably 35, at least 18% by weight of polymer. In a spinning solution for use

DK 153800 B

In the process of the invention, e.g. used in the spinning step between 40 and 56 g of poly (p-phenylene terephthalamide) with a logarithmic viscosity number of at least 3.0 dl / g per 100 ml of acid. These amounts correspond to between 18% and 22% by weight of polymer in the acidic spinning solutions described above.

It should be emphasized that usable solvents all have a high density (E ^ SO ^ 1.83, HSO ^ Cl 1.79 and HSOgF 1.74 g / ml). The use of such high density solvents 10 results in a much higher volume fraction of polymer than when using alkylamides such as hexamethylphosphoramide and dimethylacetamide (weights of about 0.9 to 1.0 g / ml). A high volume fraction is also obtained by the high concentrations of polymer in the spinning solutions.

In the process of the invention, the aim is precisely to use as high a spinning solution concentration as possible, since it has generally been found that the tensile strength of the fibers produced is increased with the polymer concentration in the spinning solution. Since spinning solutions 20 of useful concentrations are solid at room temperature, they must first be melted into spinning liquids by raising the temperature; but increasing the temperature causes polymer degradation, as evidenced by losses in the logarithmic viscosity number, and therefore the melting state 25 is sought to be minimized.

It is desirable that the extrusion of a spinning solution yield a fiber with a logarithmic viscosity number of at least 2.5 dl / g. A fiber having a given logarithmic viscosity number can be obtained by starting from a polymer with a moderate logarithmic viscosity number and operating so that degradation is kept to a minimum, or by assuming a higher logarithmic viscosity number and working with a more severe Decomposition. For purposes of the invention, the logarithmic viscosity number of the polymer in the fresh-spun fiber is used (assuming appropriate washing and drying to 15

DK 153800B

ISLAND

avoidance of unnecessary decomposition), which is defined as the logarithmic viscosity number of the polymer in the spinning solution as it is extruded. Accordingly, the logarithmic viscosity number of the polymer in the spinning solution 5, as extruded, must be at least 2.8.

The spinning solutions used in the process of the invention have unexpected stability. It turns out that the acidity of the sulfuric acid is diminished by the presence of high concentrations of the rigid 10 chain polyamides. The spinning solutions are prepared from a PPD-T polymer with a logarithmic viscosity number of 4.88 dl / g in sulfuric acid (100%) at concentrations of 46, 21.8 and 3.7 g / ml. 100 ml. The stability of the spinning solutions is tested by heating for 3 hours at 100 ° C. The polymer isolated from the heated solutions has a logarithmic viscosity of 4.2, 2.8 and 1.9 dl / g, respectively. A further sign of a diminished "acidity" in the concentrated spinning solutions is that PPD-T spinning solutions of 46 g / ml. 100 ml are essentially non-reactive with aluminum metal at 20-70-80 ° C, while spinning solutions at a concentration of 25 g / ml. 100 ml react strongly.

In some cases, it has proved advantageous to relieve the pressure in the liquid spinning solution prior to spinning.

The polyamide solvent system used as a spinning solution in the process of the invention / behaves mainly as polymer melts. A typical spinning solution of 46 g PPD-T with a logarithmic viscosity number of approx. 4 dl / g in 100 ml of 100% sulfuric acid may have a bulk viscosity of approx. 900 poise at 105 ° C, at approx.

1000 poise at 80 ° C, and then greatly increase as the spinning solution solidifies to an opaque solid below ca. 70 ° C. The bulk viscosity is increased with higher logarithmic viscosity numbers at a given concentration and temperature. The spinning fluid described above is a hazy,

ISLAND

16

DK 153800B

translucent liquid at temperatures below approx. 135 ° C, at which temperature it becomes relatively clear.

So far, spinning solutions containing approx. 49 g PPD-T per 100 ml of sulfuric acid the highest concentration that can be processed in conventional mixers, conveyors and spinning machines, due to the extremely high bulk viscosity of the mixtures. When the usual technique is used to reduce the viscosity by increasing the temperature, a high degradation of the polymer occurs. The use of more efficient mixers in combination with more efficient cooling in the mixer will allow the use of higher concentrations. The viscosity at these higher concentrations is a function of the polymer-solvent system used.

Typically, spinning solutions can be extruded at any temperature from the lowest at which they are sufficiently liquid to be processed to up to approx. 120 ° C. Since the amount of degradation is dependent on time and temperature, a temperature as low as 20 should be practically possible, preferably below 90 ° C. The spinning solutions are preferably extruded at 70-90 ° C. If higher temperatures are desired for any reason, the apparatus should be designed so that the time during which the spinning solution is exposed to elevated temperature is kept to a minimum.

The spinning solutions of this invention are usually solid at room temperature. As the temperature increases, they melt and become less viscous and translucent to transparent. They are optically anisotropic, i.e. microscopic regions of a given spinning solution are birefringence. A spinning solution depolarizes plane polarized light as the light transmission properties within microscopic areas vary with the direction. This property is associated with the existence of at least a portion of the spinning solution in a liquid crystalline or mesomorphic state. These spin-35 solutions behave anisotropically in the relaxed state.

ISLAND

17

DK 153800 B

For a well-mixed spinning solution of a given composition and concentration, the temperature at which the melting takes place is accurately reproducible and reversible. This melting property is accompanied by a heat absorption as indicated by differential thermal analysis. The melting temperature of solidified spin solutions can also be determined by measuring the intensity of polarized light passing through a thin sample and a 90 ° crossed analyzer as the temperature is raised. The melting temperature is the temperature at which the transmitted light intensity increases rapidly. Usually, the melting temperature increases with the concentration. PPD-T sulfuric acid pulp solutions of 32, 40 and 46 g per For example, 100 ml of acid have a melting point of 40-50 ° C, 63-65 ° C and 72-82 ° C, respectively. A spinning solution that is incompletely mixed and has a distribution of phases of different concentration will have a wider melting range.

As the temperature of molten anisotropic spin solution increases, a point is reached at which the amount of anisotropic phase begins to decrease. This temperature (Ta) 20 can be determined by measuring the change in the scatter of polarized light at small angles (e.g., 1 °) by passing through a thin layer of spinning solution. The Ta value increases with the concentration of the polymer, e.g. For example, the PPD-T / E 2 SO 2 - spinning solution at 32, 40 and 46 g / 100 ml - concentrations are found to have Ta values of approx. 80-100 ° C, 82-135 ° C and 110-122 ° C. Even above these temperatures, the spinning solutions are very aniostropic and give good results in the process of the present invention, but fibers with the highest tensile strength will be obtained by the spinning of spin solutions at temperatures above the melting point and below the Ta value.

The extrusion conditions are discussed under the spin debonding conditions for fibers in the following section. It is understood that the comments also apply to the method of application to film extrusion.

18

ISLAND

DK 153800 B

Spinning nozzles and all other appliance parts should be constructed of materials that are resistant to the strong acids used.

The diameters of the nozzle openings and the ratio of the length of the capillary tube to the diameter of the hole (L / D) in the spinning nozzle are not critical. Strong fibers are obtained with round openings with a diameter of 0.025 to 0.25 mm and an L / D ratio of 1.0 to 1.83. The process can also be carried out with non-round holes of various shapes, e.g. narrow slits, especially of 0.02 x 0.05 mm, 0.02 x 25 mm or 0.175 x 75 mm.

The spacing between the holes is not critical and is dictated by the structural materials and filament stability obtained by the spinning.

The jet velocity (denoted by "SH") is the mean velocity of the spinning solution in the spinning capillary tube calculated from the volume of the spinning solution passing through one aperture. and from the cross-sectional area of the opening and may be from 5.1 m per mine. or 20 even lower and to 350 m per. mine. or even higher. The minimum value for a given spinning solution and opening is determined by the ability of the spinning solution to flow continuously and cleanly. A smaller aperture diameter will give a higher minimum flow rate than larger apertures.

The spin stretch factor (SSF) as used herein is the ratio of the velocity of the fiber as it exits the coagulation bath to the flow rate. Spinning tensile factors as low as 1.0 or lower and as high as 14 or more may be used. The minimum spinning tensile factor to be used in a particular spinning solution and opening is determined by the ability to form a filament with a relatively uniform denier and the desired physical properties. The maximum usable spin stretching factor is limited by the filament damage in the method. Usually, an increase in spinning tension

ISLAND

19

DK 153800 B

The flow factor from a low value at a given flow rate fibers with higher tensile strengths and modulus and lower fracture extensions and denier. One skilled in the art can readily adjust the aperture diameter, the thickness of the gas layer, the flow rate, and the spinning tensile factor of a given spin solution and the spinning apparatus to obtain a fiber having the desired denier and physical properties.

It is important that the spinning nozzle opening be separated from the coagulation bath by a liquid layer of a gas or a non-coagulating liquid such as toluene or heptane. The thickness of the liquid layer can range from 0.1 to 10 cm or more, and is especially from about 10 cm. 0.5 to 2 cm. The use of a larger thickness increases the risk that adjacent filaments will fuse.

15 The configuration of the spinner tube 60 and the nature of the guide 57 of FIG. 1 can affect the extension and modulus of the yarn in the freshly spun condition. At the same flow rate and recovery rate, a straight tube usually provides a higher yarn elongation and lower modulus 20 with a tube constricted at its lower end. Similarly, a roller guide provides a higher yarn break extension than a tightening taper. Applicable spinner tube dimensions will vary with the germination rate and yarn value.

Various baths can be used to coagulate the fiber. Satisfactory results have been obtained with both aqueous and non-aqueous systems. Useful aqueous systems range from pure water to systems containing high concentrations of sulfuric acid (70%), ammonium hydroxide 30 or salts such as calcium chloride, potassium carbonate or sodium chloride. Aqueous baths containing organic solvents miscible with water, e.g. methanol and ethylene glycol are also useful. Examples of non-aqueous coagulation baths include 100% methanol and methylene chloride solutions containing 5-50% methanol, N, Ν'-dimethyl-20

DK 153 800 B

0 formamide or N, N'-dimethylacetamide. Bath temperatures from -25 ° C to 28 ° C are preferred. A large number of coagulants can be used at temperatures from below 0 ° C to 50 ° C or more. In particular, the temperature of the bath is kept below 10 ° C (especially below 5 ° C) to obtain the highest tensile breaking strength in the films.

Due to the degradation effect of even small amounts of acids in the yarn, a complete removal of the acid is important to achieve high tensile strength fibers. Water alone or combinations of alkaline solutions and water 10 can be used for its removal.

A suitable washing method is to spray the filament bundle as it leaves the coagulation bath with an aqueous alkaline solution (saturated sodium bicarbonate or 0.05 N sodium hydroxide), removing the surface liquid from the filaments with a wiper (e.g., a sponge) or a jet, wash with water (about 75 ° C) to reduce the acid content to approx. 1% (on dry fiber basis) and coil recovery. Such coils can be stored for short periods (up to about 24 hours in water or dilute alkaline solutions before final washing). Preferably, the final wash (e.g., with 75 ° C hot water) should reduce the acid or base content to below 0.01% (on a dry basis).

While small amounts of yarn can be washed and neutralized on the bobbin, it is preferred that the yarn be washed as such in thin layers in troughs, on rollers sprayed from above with the spray liquid, on screens, belts or the like. In a continuous process, the filament bundle can be washed and neutralized with a fluid moving at the same speed as the filaments.

30 The carefully washed fibers can be dried on the coil with air at up to 150 ° C. The fibers may conveniently be dried on heated rollers (e.g., 160 ° C). If the fibers are dried under a tension of less than approx. 0.3 gpd, which is the preferred method, the properties do not change very much. Use of voltages above 0.3 gpd decreases 21

DK 153800B

ISLAND

elongation and increases the modulus relative to what is obtained by drying without voltage.

The properties of the yarns in the freshly spun condition can be changed with heat treatment. Heating a yarn under tension, especially in an inert atmosphere, at a temperature of 150 ° C to 550 ° C increases the yarn module from approx. 15 to 100% and reduces the yarn extension by approx. 50%. The module increase is greater with increased voltage and temperature. Typical stresses and times used for impact at 10 150 ° C are approx. 2 to 12 gpd for 1.5 to 6 seconds and at 550 ° C 0.5 to 2 gpd for 1-6 seconds. At low and medium temperatures, the yarn tensile strength does not change significantly, but it can be reduced after treatment at 450 ° C or more.

Yarns to be heat treated are usually dried beforehand, but the effect of heat treatment can be made with wet yarns directly from washing or with wet yarns by a slight extension of the heating time.

Experimental Procedure 20 Logarithmic Viscosity Number ·

The logarithmic viscosity number is defined by equation ln (h rel) 25 c in which c is the concentration (0.5 g of polymer or fiber in 100 ml of solvent) of the polymer solution and rel (relative viscosity) is the ratio of the flow time 30 of the polymer solution to the solvent measured at 30 ° C in a capillary viscometer. The solvent is concentrated sulfuric acid (95-98% E 2 SO 2), unless otherwise indicated.

The filament properties are measured on fibers that have been conditioned at 21 ° C and a relative humidity of 65% 35 (R.H.) for at least 16 hours, unless otherwise indicated. twine

ISLAND

22

DK 153800B

properties are measured on yarns that have been conditioned at 24 ° C and 55% R.H. for at least 16 hours. All the measurements are performed within the fiber conditioning range.

Tensile strength (Ten), fracture elongation (E), initial modulus (Mi), and toughness (tensile toughness) (Tou) are obtained by breaking a single filament or multifilament yarn in an Instron test apparatus (Instron Engineering Corp., Canton,

Mass.).

Some filaments are broken with measuring lengths (distance 10 between claws) of 2.54 cm. The mean of the results for three filaments is calculated. The yarns are given a twist of three turns per second. 2.54 cm (below 0.1 gpd voltage) and broken at 24.5 cm measuring length. All samples are extended at a constant degree of elongation (10% elongation per minute for fibers having an E value of less than 8% and 60% elongation per minute for fibers having an E 'value of 8-100%) until the sample broken.

The denier value of a single filament (d.p.f.) is calculated from its functional resonant frequency determined by vibrating a 7-9 cm fiber length under voltage, changing the frequency (A.S.T.M. D1577-66, part 25, 1968). This filament is then used in the tensile strength test.

The denier value of the yarn is determined by weighing a known length (at 0.1 gpd voltage). A length of 90 cm is appropriate.

Tensile breaking strength (g / denier g.p.d.) rupture elongation (%), initial modulus (g.p.d.) and toughness (gram-centimeter per denier centimeter or simple g.p.d.) as defined by A.S.T.M. D2101, part 25, 1968 is obtained from the power extension diagram and the measured denier. In practice, the measured 30 denier of the sample, test conditions, and sample identification are fed to a computer before the trial is started. The computer reproduces the power elongation diagram of the fiber as it breaks, and then calculates the fiber properties.

It should be noted that different values 35 are obtained with single filaments (filament properties) and with multi-

ISLAND

23

DK 153800B

filament yarns (yarn properties) of the same sample. The filament breach forces are higher than the fire breach forces in the Turks - typically approx. 1.2: 1, the filament rupture extensions are higher than the yarn rupture extension and the filament modules are lower than the yarn values. If nothing is specified, all of the properties listed below are filament properties.

The physical properties of all the yarns in the examples are measured with a yarn with three twists per minute. 2.54 cm. This results in a different twist multiplier (SM) 10 for yarns of different denier value: "M _ (twist / 2.54 cm) \ denier of yarn bm 73 15 It has been observed that the initial module of a yarn decreases, as the SM value increases. The module of a 700 denier yarn (S.M. 1.08 at 3 turns per 2.54 cm) will e.g. be approx. 5% lower than the module of an equivalent 200 denier yarn (S.M. 0.58 at 3 turns per 2.54 cm).

The film force extension and break elongation properties are measured with films that have been conditioned in the same environment and in the same way as used with yarns. The test results are obtained by breaking a film, using a sample length of 5 cm at 100% elongation per minute.

25 minutes.

Spin solution viscosities are measured with a Brookfield Viscometer with spindle # 7 at 10 rpm. minute.

The orientation angle 0V of the fiber as discussed in 30 "X-Ray Diffraction Methods in Polymer Science" by Lercy E. Alexander, Wiley-Interscience (1969) Chapter 4, p. 264, is determined by the following method. A wide angle X-ray diffraction pattern (transmission pattern) of the fiber is made using a Warhus pinhol camera. The camera 35 consists of a collimator tube with a length of 7.6 cm with two 24

ISLAND

DK 153800 B

lead pinols with a diameter of 0. 0635 cm at each end and at a distance of 5 cm between sample and film. A vacuum is produced in the camera under the influence, the radiation is produced using a Philips X-ray unit (Cat. No.

5 12045) with a copper fine-focus diffraction tube (catalog no.

14000320) and a nickel beta filter. The unit is operated at 40 kv and 16 ma. A fiber sample holder with a thickness of 0.051 cm is filled with the sample. All the filaments in the x-ray are kept essentially parallel. The diffraction pattern 10 is reproduced on a Kodak No-Screen ^ medical X-ray wave film (NS-54T) or the like. The film is affected for a sufficient period of time to obtain a pattern that is acceptable according to conventional standards (e.g., a pattern in which the diffraction spots to be measured have an adequate photographic density, e.g. 0.2 and 1.0 to be accurately readable, usually an operation time of about 25 minutes is appropriate, however, a smaller operating time may be suitable and even desirable for highly crystalline and oriented samples to obtain a more accurate reading. 20 readable pattern.

The arc length in degrees at the half-maximum intensity (angle to points with 50% of the maximum intensity) of one of the main equatorial spots is measured and taken as the orientation angle of the sample. The specific arc used to determine the orientation angle of fibers described in the following examples, where more than one main arc exists, is that which appears at the higher value of 2 Θ.

In some cases, especially poly (p-phenylene-chloro-terephthalamide), the diffraction pattern of the heat-treated fiber has been found not to contain any major equatorial spots. When this is the case, two spots are usually observed, one on each side of the equatorial position. The orientation angle of these fibers is then measured on a suitable meridional arc (especially 006 backbone).

. DK 153800 B

25

ISLAND

using a diffractometer, and this angle is compared to the obtained orientation angle of the corresponding arc by electron diffraction as described later.

5 The orientation angles of the fibers produced are determined by a densitometer method from the X-ray film.

The azimuthal intensity distribution of the diffraction arc is obtained using a Leeds and Northrup microphotometer (Catalog No. 6700-P1) whose electronic components 10 have been replaced by a Keithley 410 Micro-Microamperter (Keithley Instruments Inc., Cleveland , Ohio). The measurements from this device are fed to a Leeds & Northrup Speedo-max Recorder, type G.

In measuring, the film is placed on a disk, the instrument is focused on the film, and the center of the diffraction pattern is made coincident with the center of the disk. Both of these centers are made to coincide with the luminous flux of the instrument. The disc and the film are moved so that the luminous flux is allowed to pass through the most intense area of the diffraction spot, the opposite spot is checked to ensure accurate centering, and after any necessary fine tuning is performed, the azimuthal rendering is performed. intensity track at least one rotation of the film at 360 ° on a suitable coordinate paper. A curve is obtained with the 25 two main peaks, where the intensity axis is considered the vertical axis and the angular displacement the horizontal axis. A baseline is drawn for each peak as a straight line tangential to the minimum on each side of the peak. The perpendicular is folded from each maximum peak to the baseline. Through the center of each of the perpendicular (i.e., "half-intensity" point), a horizontal line is drawn which intersects each leg of the respective curves. The leg-to-leg length of each of the horizontal "half-intensity" lines is converted to arc degrees as follows. The horizontal distance equiva-35

ISLAND

26

DK 153800B

Late to 360 ° angular displacement is determined by rotating a given point through 360 ° followed by a direct measurement of the horizontal displacement for such rotation. One of the two main peaks mentioned above can e.g. is used for this purpose. By direct ratio calculation, the "half-intensity" leg-to-leg distance is converted to degrees. The mean value of two arcs is calculated and this is the orientation angle referred to in this specification.

Values determined by this method have been found to be 10 accurate - 0.7 ° at the 95% probability level.

Method of Determining Apparent Crystalline Size The X-ray diffraction scans of the fibers produced by the method of the invention differ depending on the chemical structure, crystallinity and degree of order and orientation of the fiber. A measurement of the apparent crystallite size (TKS) for each of the observed main diffraction peaks is calculated from data obtained from an X-ray diffraction pattern, using a throwback technique to reproduce the intensity trace by means of an X-ray diffractometer.

A Philips X-ray wave generator, a wide-angle diffractometer and an electronic circuit mirror are used to reproduce the diffraction pattern. Ca. 1.5 meters of yarn is wound around a modified Philips sample holder with the axis of the yarn perpendicular to the mechanical axis (2 Θ) of the diffractometer. The modification of the sample holder consists of cutting of approx. 21, 0.25 mm wide along the corner of the holder and placing a thin layer of lead film across the lower side of the rectangular opening so that only the fibers at the top will be exposed to the X-ray wave flow. Using a nickel-filtered copper radiation (1.5418Å), a trace of the diffraction intensity from 6 ° to 38 ° 2Θ is plotted with a scan rate.

ISLAND

27

DK 153800B

rate of 12.7 ram per per minute, at a time constant setting of 2, with 0.5 ° scattering and receiving openings and using a scintillation detector with a heat pulsation analyzer, 2Θ being the angle between non-5-diffracted and diffracted current. A full scale impact of the recorder is set such that the entire diffraction curve remains on the scale which is linear but with the largest response possible and preferably with a maximum intensity of at least 50% of the scale.

The diffraction scans or diffractograms observed for fibers made by the process of the invention, when the sample is crystalline, consist of patterns with several peaks. In most cases, two main peaks are located in the area from approx. 17 15 to 25 ° 2Θ (for most samples 19 to 24 ° 2Θ). In a few cases, one of the two peaks will be visible only as a bend, however, which will be sufficient to locate its position. Sometimes only a significant narrow crystal peak is observed. The method used to determine the apparent crystallite size (in "X-ray Diffraction Methods in Polymer Science" by L.E.

Alexander, Wiley-Interscience, 1969, Chapter 7) are listed below.

If the sample is not crystalline, the diffractogram will contain only a single very wide peak. In this case, the apparent crystallite size is considered zero.

A baseline is first made on the scan, drawing a straight line between the points on curve 30 at 9 ° and 36 ° 2Θ. Then, the perpendicular from the top center of the selected peak is dropped to the baseline, and the midpoint between the apex of the peak and the baseline is marked on the vertical line. A horizontal line is then drawn through the midpoint. This line can cut off one shoulder of the top 35 pen, or if the minimum between the two main peaks is low

. DK 153800B

28

ISLAND

enough, both shoulders. The width of the selected peak at this point is obtained either by measuring the distance of the horizontal line from one shoulder to the vertical line and multiplying it by two or, if possible, the distance between both shoulders along the horizontal line. The distance is expressed as the peak (or "line") - the width in radians obtained by using the scale of 2Θ to convert the observed line width in cm to degrees and optionally radians. If B is the observed line width in radians, the corrected line width is beta in radians (cf. the above literature reference page 443) S = \ | b2 -b2 where b is the instrument width in radians, b is determined by measuring the line width of the localized peak at ca. 28 ° 2Θ on the diffractogram of a silicon crystal powder sample from the distributors of the X-ray wave apparatus (Philips Elec- tronic Instruments, Mount Vernon, N.Y.), the constant b is the line width in radians. The instrument settings used are: scan rate 0.125 ° 2Θ per per minute, time constant setting 8 and curve drawing 2.54 cm per minute. minute.

Finally, the apparent crystallite size 25 is associated with the chosen throwback given by TKS = - β cos Θ 30 in which K is taken as one (unit), X is the x-ray wavelength (here 1.5418 Å), β is the corrected line width in radians (see above), Θ is the Bragg angle (1/2 of the 2o value of the selected peak as determined from the diffractogram).

The primary apparent crystallite size 29

ISLAND

DK 153800 B

(PTKS) used in the structural definition of products made by the process of the invention is defined for the fibers having more than one significant crystal peak as the apparent crystallite size calculated for the peak found at the smaller (minimum) value of 2Θ.

In this measurement, it is observed that the line width is affected by stresses and impurities in the crystals (which are of unknown size) and by the crystallite size, and 10 for this reason, the obtained crystallite size is apparently called.

Values determined by this method have been found to be + accurate - 2Å at the 95% probability level.

15 Quantitative Lateral Crystallite Order Trial Introduction

The experiment involving the use of electron diffraction of thin fiber sections demonstrates that the products produced have a uniform lateral arrangement of the crystal planes which may be shown to be associated with tensile strength of improved products. The preferred structure has a set of planes whose mean position is parallel to those planes containing the fiber axis and radius.

The test procedure identifies the largest (i.e., the most intense) of the equatorial reflections in a conventional fiber X-ray diffraction pattern (obtained by the method of determining the apparent crystallite support). Most fibers have two main backscatter corresponding to d spacing from approx. 3.9 to 30 4.9Å and are referred to as "class I structures". Some fibers have only one main throwback corresponding to the same d-gap space and are determined as "class II structures".

An electron diffraction unit is calibrated so that the above main backslashes can be identified in the electron diffraction pattern of specified thin fi gures.

DK 153800B

bersections, since this test procedure only applies to these main throwbacks.

The density of the principal reflections in the electron diffraction patterns is measured in a specific way and a lateral crystallite order (L.K.O.) value is calculated.

cut Production

The fibers (or films) to be examined are heated relaxed or at low voltage for a period of approx.

10 for 10 seconds at a temperature of 400-500 ° C, selecting the exact conditions to avoid degradation or destruction of the fiber. This heating is usually carried out by passing the fiber through a nitrogen-filled heated metal tube under a voltage just sufficient to avoid contact with the tube.

A bundle of fibers exactly aligned (about 1 mm in diameter and 5 cm long) is immersed in an epoxy resin. A small section is cut from the specimen and glued to the end of a tapered rod holding.

20 Heated film samples are most easily immersed using small "ΒΞΕΜ" capsules (e.g. from Ladd Research Industries, Burlington, Vermont). A section is cut from the tapered tip of a capsule along a diameter for inserting the sample inserted at the corner of the film 25 ° to the capsule axis. The capsule is then filled with epoxy resin and polymerized.

0.1-0.2 μπι thick sections are cut from the immersed fiber or film samples, preferably using a diamond knife and a microtome designed to produce 30 very thin sections (eg "Ultratome" from LKB Stockholm, Sweden) at a cut-off rate of 1 mm per second. second or less. The samples should be oriented during cutting so that the corner of the knife is perpendicular to the long axis (extrusion direction) of the fiber bundle or film and is parallel to the thickness direction of the film.

31

ISLAND

DK 153800 B

Fibers and films with a Class I structure are cut at an angle of 45 ° to the long axis of the sample.

Fibers and films with a class II structure are cut so that the molecular chain axis is approximately perpendicular to the surface of the section (determined using a universal step polarization microscope).

The film section must be manufactured so that it contains at least one long side (parallel to the cutting direction) and a short side (perpendicular to the cutting direction) that are original extrusion surfaces.

Applicable sections should be of such quality that they do not contain significant knife marks, shadow marks, folds or compression disorders (cf.

15 D. Kay, "Techniques for Electron Microscopy," 2nd Edition, page 220; FEW. Davis, Philadelphia 1965).

electron

The fiber sections prepared above are transferred to electron microscopy grids and placed in the usual high resolution position in an AE1 EM-6G electron microscope operating at an accelerating voltage of 100 KV. The half-plate image tube is turned into position. The microscope is set to diffraction and the coarse diffraction tuner is rotated counterclockwise 25 times (to obtain an enlargement of approximately 600 times) from the diffraction focus position. The section to be examined is rotated until the long axis (approximately parallel to the cutting direction and passing through the center of the section) of the fiber (or film) section is 30 perpendicular to the corner of the half-plate mesh. The selected area aperture (hereinafter "aperture") (with an effective diameter of about 1 mm in the object plane) is placed along the short axis (through the center of the section and perpendicular to the long axis) of the fiber section centered at a point one or 35 two aperture diameters from the corner of the fiber section (this will

ISLAND

32

DK 153800B

referred to as the S position). The diffraction pattern is then focused, the photographic film (du Pont Ortho-S) is advanced a little further than halfway into the column and the curve is drawn. The G'rovdif fraction adjuster is turned once again counterclockwise and the aperture is moved to a position along the axis of the fiber section and centered at a point spaced one or two aperture diameters from the corner of the fiber section (this will in the the following will be referred to as the L position). The diffraction 10 pattern is set, the photographic film is advanced to the column and the diffraction pattern is plotted. The process is repeated with at least three different fiber sections.

FIG. 2 shows an arrangement of a fiber section 15 (2) (cut by 45 °) the opening (4) and the corner (6) of the half-plate mask in the microscope image before the S-position diffraction pattern is taken. Also shown is a long axis (8) of the section perpendicular to the corner (6), a short axis (7) and the position (9) of the opening for the L-position pattern.

Sections of film are oriented as above, opening at any location one or two diameters from one of the two long corners of the section and at one point one or two aperture diameters from the short corner of the section near its center of S and L respectively. -positions.

The procedure described above for processing the films yields three photographic negatives with each two electron diffraction patterns (e.d.) and one line (made from the corner of the half-plate mask) for each pattern.

FIG. 3 shows a typical e.d. pattern taken in the S-30 position of a poly (p-phenylene terephthalamide) fiber made in accordance with the invention. An index line (18) is drawn through the center of the pattern parallel to the corner of the half-plate mask. The patterns have pairs of diffraction arcs (10, 12 and 14) with each arc of a pair of equal radii 35 (from the center of the pattern). Each arch of the pairs has its 33

ISLAND

DK 153800 B

maximum density point (hereinafter referred to as "maximum" of the arcs corresponding to the principal equatorial reflections in the X-ray fiber pattern) as measured in an azimuthal direction, located on a line (not shown) (hereinafter "the center line") passing through the center of the pattern.

The center is hidden by a high-density circular region (16) caused by an incident electron flow. Arches 10 and 12 are identified as the main reflections for this Class I structure and therefore have "maximum".

FIG. 4 shows an e.d. pattern taken in the L-position of the same section as used for making FIG. 3. In this and the following figures, the dense portions around the center (20) have been omitted and only the main backscatter is shown.

FIG. 5 shows an e.d. pattern in the S position. The localization of maxima (10, 11 and 12) corresponds to the main backscatter by X-ray.

A section of a fiber which is not made according to the invention, but which is typical of poly (p-phenyl terephthalamide) fibers made by a conventional wet-spinning, provides e. 4 in both the S and L positions.

Quality tests for diffraction patterns - class I structures

Suitable e.d. patterns have the following characteristics: A. At least a few maxima with a center line parallel (within - 30 °) to the index line and one of the following designs.

30 (1) another pair of maxima with a center line parallel (within - 30 °) to the index line (cf. FIG.

4), or (2) another pair of maxima with a center line of the wine + corner (within - 30) on the index line (cf. Figures 3 and 35 5), or 34

ISLAND

DK 153800 B

(3) a diffraction ring (i.e., a main 360 ° cap without maxima); (4) in any case, the above types of patterns may have a second pair of maxima with the same radius as one of the above maxima (cf. Figures 5 and 6).

B. Two main diffraction rings.

If the properties under A or B are not obtained, a new diffraction pattern must be made with a different section, or a different diffraction pattern must be made with the same section with a slight displacement of the selected area aperture position.

If the center lines of two pairs of maxima are perpendicular to each other (within 30 °) in the S-position pattern, the same reflections in the L-position must be either (1) 15 on the center lines parallel (within 30 °), cf. FIG. 3 and 4, or (2) on the initially mutually perpendicular (within 30 °) center lines with the inner and outer reflections interchanged. The absence of conditions (1) or (2) is a sign of cut-off disorder and new 20 sections should be cut and examined.

The maxima and / or head rings in a set of patterns for a given sample are denoted by "a" or "b" when examining S-position patterns.

If the S-position pattern has maxima on a line 25 perpendicular (within - 30 °) on the index line (cf. Figures 3, 5 and 6), all the rings and / or maxima in both the S and L-position patterns corresponding to to each other in radius (from the center of the pattern) to these maxima, are marked "b", and the other principal maxima or rings, if found, must be marked "a".

If there are no maxima on a line perpendicular (within 30 °) to the index line, and if (1) two pairs of maxima exist that can be connected by parallel lines (within 30 °) to the index line, cf. FIG. 4, or 35 (2) if both rebounds are completely poor,

ISLAND

35

DK 153800B

or (3) if a pair of maxima and a ring are found, the outer (greater distance from the center of the pattern) pair of maxima or the outer ring must be designated "b" and the inner "a".

5

Quality tests for diffraction patterns - class II structures

Suitable e.d. patterns have the following characteristics: A. a single ring in both the S and L position patterns or B. a pair of maxima with a center line within 25 ° (a) parallel or (b) perpendicular to the index line of The S-position pattern, and an L-position pattern with a pair of maximum with a center line that is perpendicular or parallel to the index line of conditions (a) and (b) for the S position within 15 °.

densitometry

The machined film with the E.D. patterns is examined with a Joyce-Loebl microdensitometer, using a 10X objective, a 20: 1 ratio arm, 1.6d slit opening and a 4mm slit opening. Each pattern of a Class I structure is scanned along a center line connecting the most parallel maxima with the index line or in the absence of 25 maxima in the area (eg, for a ring) along the index line.

Class II structures with a uniform ring such as the main rollback are scanned twice through the center of the pattern, (1) parallel and (2) perpendicular to the index line. A class II pattern with a pair of maxima 30 is scanned along the center line of the maxima and on a line through the center of the pattern perpendicular to the center line.

FIG. 7 shows a densitometer groove (4) along the center line of the maxima (10) of the pattern of FIG. 4. The peaks (26 and 28, designated "a" and "b") are due to the maxima (10) and 35 (12) of FIG. 4. The maximum density plateau (30) is due to this

ISLAND

36

DK 153800B

scaled center and a baseline appears.

Analysis of densitometer traces

The tests require that the ratio of the heights 5 (proportional to the density of the e.d. patterns) of the peaks is known and that the peaks are designated "a" or "b" referring to the e.d. pattern. Since the peaks can be close and overlap, a correction should be made if this is the case. One method of doing this and the definition of the peak height is discussed below. In each case, an arc background line (32) is drawn - cf. FIG.

8 - with a flexible curve line between the bottom (34) of the center groove (35) and the lower outer portion of the groove (36).

15 1. Trace with two dissolved peaks

The outer shoulder (27) of the inner top (26) is extended by a straight line (38) drawn parallel to the substantially linear upper portion of the outer shoulder (29) of the outer top (28). The inner shoulder of the outer top (28) 20 is extended by a line (40) drawn parallel to the substantially linear upper portion of the inner shoulder of the inner top (26). The peak height of the peak is the smaller vertical distance between the peak and (1) the background line (2) the extension of the shoulder of the second peak. In FIG. 8 is the top-25 height of the top (26) measured on the vertical line (42) from the top to the background line. The top height of the top (28) is measured on the vertical line (44) between the top and the extension (38) of the shoulder.

30 2. Trace with two peaks, one dissolved and the other a friend depot

These are dissolved by analogy as above - cf. FIG. 9. Place a piece of parchment paper over the track and draw a horizontal reference line. The portion of the groove 35 comprising the turning point (28) of the unresolved peak and 37

ISLAND

DK 153800 B

and the shoulder (31) of the turning point is drawn on the paper. The paper is then moved, keeping the reference line horizontal so that the drawing of the shoulder falls on top of the shoulder (27) of the dissolved top and the lower shoulder (33) of the turning point. The drawing is transferred using carbon paper to the original track, thereby obtaining a corrected shoulder (44). The peak height of the turning point (28) is the maximum vertical separation between the original and the corrected shoulder of this peak. The peak height of the dissolved peak (26) 10 is the vertical distance from the peak to the background line.

3. Tracks with a single top

The peak height is the vertical distance from the top to the background line.

15 A. Tracks with two unpinned peaks

The peak heights are considered to be the same, and the relationship between the two top heights is taken as one, cf. FIG. 10, showing a half scan of the pattern of FIG. 6th

20 Calculations

The sum of the densities of the measured head back cost in a half scan (outer center) should be at least 0.5 above the density of the background line.

The scanning of the entire pattern should provide a substantially 25 symmetrical trace with the heights (measured over the background line) of the right-hand and left-hand peaks associated with the most intense maximum in the pattern, each not more than 20% from the mean of the left. and right - hand values.

Based on the structural factors that determine the peak heights, a parameter A has been chosen as a measure of the degree of the preferred structure in the manufactured products. For class I structures A = (a / b) „/ (a / b) T where a / b is the ratio of the peak heights of the diffractions a and b, and the indices S and L refer to the S and L positions, respectively. .

38

ISLAND

DK 153800 B

In the case of Class II structures A = (H ^ / ^) · ^ where and ^ are defined as follows: In a (single) annular e.d. pattern, and H2 are the peak heights of a scan perpendicular to the index line and parallel.

5 For an e.d. pattern with a single pair of maxima, and H2 are the peak heights of a scan (a) perpendicular (within 25 °) on the index line and (b) perpendicular to the scan direction (a). The indices S and L refer to patterns taken with S and N positions, respectively.

10 A value of "A" (Ar) is calculated using values of a and b on the right side of the densitometer track for both positions. Another value of "A" (A ^) is calculated, using values of a and b on the left half of the densitometer trace for the same patterns.

The lateral crystallite order (L.K.O.) value of a fiber (i.e., for a given section) is the mean of Ar and A- ^ for this section. If both values are finite, their mean value is calculated directly. If one of the values consists of a finite value and an infinite value, the mean value of their reciprocal values is calculated and the reciprocal value of this mean is indicated. If both values are infinite, the mean is infinite.

The following are the mean L.K.O. values and the range of the values (used "infinitely") of three tested sample filaments made according to the embodiments identified by No. below.

Example Mean LQO Value Range 1 i i-i 30 2A (a) 72 24-i (b) 26 9.5-45 (c) i i-i 2B 18 5.5-34 4a i i-i 35 i i-i

ISLAND

39

DK 153800B

Example Mean LQQ Value Range b 34 29-38 bx 114 72-ie 1.4 1.2-1.6 5 eL 11 3-25 f 68 62-79 f1 i ii g 152 96-ih 118 20-306 10 hL 35 27-44 ii ii j 1.6 0.9-2.8 ki ii kx 7.2 6.6-8.0 15 1 38 20-ir 1.8 1.7-1.9 s 1 , 2 0.6-2.2 5a 44 15-ic 6.5 5.5-8.3 20 8 d 72 15-132 e 462 154-if 105 35-ig 37 15-81 h 65 12-110 25 ii ii The LKO values for PPD-T filaments made by conventional wet-spinning methods range from 0 to 4.5, with most of the values being about. 1.0.

30

fiber density

The fiber densities are measured using a plastic density gradient tube method specified in ASTM Method D 1505-68, Part 27, 1970. This method is modified using heptane carbon tetrachloride at 25 ° C.

0 40

DK 153800B

as the liquid system for the density gradient tube. The densities of four loosely knit short (about 1 to 2 cm) lengths of filament or yarn are determined and the mean given.

5 In the following, density values (for three 3 significant figures) (in grams / cm) are given for the fibers of the Examples.

Example Table Fiber Density 10 1 Freshly spun 1.44 2 A 6 a 1.45 2 A 6 b 1.45 2 A 6 c 1.45 2 B 3 1.42 15 4 3 a 1.48 ax 1.43 b 1 , 42 e 1.40 βχ 1.42 20 f 1.41 fl 1.42 g 1.43 h 1.43 hx 1.46 25 i 1.43 j 1.47 k 1.39 kx 1.36 1 1 , 43 30 r 1.46 s 1.40 5 4a 1.45 b 1.46 c 1.44 35 8 6 d 1.45

ISLAND

41

DK 153800B

Example Table Fiber Density e 1.45 f 1.44 g 1/41 5 h 1.45 i 1.43

The fully aromatic polyamide fibers produced by the process of the invention should preferably have a density of at least 1.38 g / cm to ensure that the fibers have not contained too many bubbles which will greatly reduce the tensile strength.

Example 1 PPD-T having a logarithmic viscosity number of 5.4 dl / g is mixed in a beaker with sulfuric acid (99.7% 3 SO 100 ml of acid (20% by weight). The crude mixture of dough-like consistency is transferred to a blender consisting of two open top cylinders (each with a capacity of about 250 ml) connected to a stainless steel tube which is also connected through a T to a swan neck which is temporarily closed. Each cylinder has a filter package [3-50 mesh screens / 1-325 mesh screen / 3-50 mesh screens, (mesh / 2.54 cm)] at the bottom. The mixer is equipped with two 25 pistons that close each cylinder tightly. A small hole in each piston is opened for an initial test of each piston to ensure removal of air and then closed. A water bath with a temperature of approx. 95 ° C is placed around the mixer. After approx. Within 1-2 hours, the polymer solvent mixture is passed through the pistons from one cylinder to the other with a total of approx. 5 recycles. With the entire mixture, now a spinning solution, in cylinder 1 (and the connecting line), the plug is removed from the swan neck connected to the connecting line, and the swan neck is connected to an electrically heated spinning block

ISLAND

., ..... DK 153800B

4 2. --'- J

with a stainless steel felt filter (Dynaloy X5 manufactured by Fluid Dunamics, Inc., Morristown, N.J.) and a 1.27 cm diameter spinning nozzle with 0.05 mm diameter holes. The water bath at a temperature of 95 ° C is placed again around the mixer and the first length of the pipe. The short length of pipe between the water bath and the spinning block (100 ° C) is equipped with a steam jacket.

The spinning solution is pumped from the mixer through the spinning nozzle at a flow rate of 64 meters per minute.

10 minutes through a 1 cm thick layer of air vertically into water at 4 ° C using a spinner tube and a winding member as shown in FIG. 1 at a speed of 442 m / min, giving an SSF value of 6.9.

The fibers, after careful washing and air drying, have a logarithmic viscosity of 4.8 dl / g and a d.p.f. value of 0.92.

A portion of the dried multifilament is assembled into yarn with a total denier of 183 and passed through a 3.05 meter long tube containing nitrogen at 525 ° C under a voltage of 1.4 gpd at a rate giving a residence time of approx. . 2 seconds (91 meters per minute). The yarn is stretched only approx. 1,005 times its original length.

The properties of freshly spun fibers and of the bonded and heat treated fibers are set forth below.

In the freshly spun After heat-condition treatment

Filament, Ten./E/Mi/tou 26 / 3.7 / 750 / 0.50 21 / 2.2 / 950 / 0.23

Yarn, Ten./E/Mi 22.8 / 2.8 / 811 20.5 / 1.7 / 1103 30

Yarn, twine, gpd 0.314 0.164

Orientation angle 11.2 ° 9.0 °

Apparent crystal size 40 Å 109 Å 35 43

ISLAND

DK 153800 B

Example 2A, A PPD-T polymer with logarithmic viscosity of 6.0 dl / g is added to sulfuric acid (99.7% H 2 SO 2) at 40 ° C in a water-coated commercial flat mixer through a top 5 conduit for over 2 minutes to obtain an amount of 46 g polymer per 100 ml of acid. The mixer is closed and placed under a vacuum of 68.5 to 76 cm Hg. The temperature of the water jacket is increased to 85 ° C and the planar blades are started at low speed. After approx. In 12 minutes, the temperature of the cooling jacket is reduced to 77 ° C, giving a temperature in the solution of between 79 and 82 ° C. The mixture is continued for approx. 2 hours. The solution then has a bulk viscosity of 2300 poise.

The spinning solution is transferred to a glass-lined boiler surrounded by a water cooling jacket (90 ° C). A vacuum of approx. 69-76 cm Hg for approx. 30 minutes to remove any air bubbles caused by the transfer. The spinning solution is pumped from the boiler through a transfer line enclosed by a spiral conduit with hot water (90 ° C) to an electrically heated (80 ° C) spinning block

and connected to a gear pump. The gear pump directs the spinning solution through a second passage in the block to a water-clad (80 ° C) spinning package containing a stainless steel blanket held in place by a support shield and a spinning 25 nozzle with a diameter of 12.7 mm containing 100 holes of 0.050 mm diameter. The spinning solution is extruded from the spinning nozzle at a flow rate of approx. 63 m per per minute vertically through a 5 mm layer of air into water of 1 ° C in a spinning tube as shown in FIG. 1. Filaments a and b 30 are made, using a free-rotating roller under the spinner tube to guide the wire string to the winding member, while a ceramic rod is used for filament c. Multifilament is wound at different speeds on a coil while spraying water (50 ° C). The yarn coils are stored in a water tank. The coils are then immersed in 0.1 N

ISLAND

44

DK 153800B

sodium bicarbonate and further extracted with water (70 ° C) on a forward coil extraction apparatus of the type disclosed in U.S. Patent No. 2,659,225.

The extracted multifilament is recovered and dried on coils at 70 ° C. The properties of the dried multifilament with a logarithmic viscosity number of 5.2 dl / g are given for the fiber types a, b and c in Table VI. These fibers have spin drag factors of 1.5, 3.4 and 4.4, respectively.

B. A spinning solution containing 46 g PPD-T (logarithmic viscosity number of 5.9 dl / g) per ml. 100 ml of sulfuric acid (above 99% H2 SO4) is mixed and extruded from a gap of 0.63 x 8.9 mm at a flow rate of approx.

19.5 m / min through a 3.2 mm thick layer of air into a 1.6 x 25 mm vertical water flow of 7 ° C, and the film is passed under a ceramic bar and wound onto a coil with an SSF. value of approx. 2.3. The coil is sprayed with a saturated sodium hydrogen carbonate solution. After neutralization, washing and drying, a 871 denier film has a Ten./E/Mi 18 / 5.7 / -360 at refraction, using a 5 cm gauge length 20 at a 100% elongation rate. minute. Conditioning and testing is carried out under conditions used for yarns.

The film has a logarithmic viscosity number of at least 5.0 • dl / g.

Example 3

This example demonstrates the use of other solvents and describes variations in the process to determine factors which are important for the achievement of fibers having the desired tensile strength of at least 18 gpd to avoid undesired results. Therefore, some of the fibers below this value are not made according to the invention.

Spinning solutions of PPD-T with a logarithmic viscosity number of 5.4 dl / g (4.6 for objects f, k, m 35 and n) and various acids and acids containing additives.

ISLAND

45

DK 153800B

ver are prepared by hand mixing followed by 15 to 120 minutes of mixing in a mixer according to Example 1. The spinning solutions are extruded with an apparatus as described in Example 1 through a spinning nozzle with holes of diameter 0.016 mm through a 1 cm thick layer of air. 1-3 ° warm water, rewind, wash thoroughly in water and air dry on the coil.

Specific conditions and results are given below. The solvents used are HSO ^ Cl, 10 HSO ^ F, HSOgF / H ^ SO ^ mixture (49/51 wt) and (100%) for the fibers a, b, c and d. The solvent for fiber e is a mixture of FSOgH and hydrogen fluoric acid and, for the fibers, a mixture of an additive and sulfuric acid (100%). The recovery rates range from 185 (fiber j) to 610 (fi 15 ber g) meters per second. minute. The concentration of spinning solutions ranges from 34 (fiber a) to 47 (fiber f) grams of polymer per 100 ml of solvent and additive. Other specific conditions and fiber properties are given in Table I.

It is observed that the use of sulfonic acids 20 as additives to the fibers f and g gives a lower spin solution viscosity than with sulfuric acid alone.

The spinning solution for fiber e containing hydrogen fluoric acid has a melting point of approx. 50 ° C lower than the melting point of a fluorine sulfuric acid spinning solution (eg, for fiber b) and can be spun at a lower temperature.

The fiber g has an exceptionally high yarn modulus in the freshly spun condition. Similar high values have been obtained with spinning solutions containing trifluoromethanesulfonic acid as additive.

The apparent crystallite size is in each case less than 52 Å.

The amount of additive that can be tolerated under normal spinning conditions of the spinning solution is limited. Attempts to make fiber f using a 60/40 ratio of additive to solvent g.

ISLAND

46

DK 15380GB

is only a paste that cannot be extruded. Testing on the production of fiber m using a 20/80 ratio of additive to solvent to 20% polymer gives a highly viscous mixture that cannot be extruded.

5 Attempts to make fiber j using a 40/60 ratio of additive to solvent give only a dry crumbly mass.

10 15 20 25 30 35

DK 153800 B

47 and

and −G t n • Η φ X

g + JHinHCMOO no Γ "in in OHO -tf cm • P-H'G '*“ * ·' - - - * · "• ricn <ί in in w in« 3 <«^ p ^ ^ ^ mm ^ HO '

g λ: η t n and g ο · Η + J

| G> m • η Η θ 'π ιο ιη η Η Ο cm ιη -3 * ιη co ^ ν * «· *. ν * «» ** · Q) · (Μ ϊ Ν (Ν ΙΟ Η Η Η OO oo CM 00 ΓΟ 00

pQ Q G

W'dOOOOO Ο Ο Ο Ο Ο Ο Ο Ο Ο βτΐ & ΓΟΟ ^^ 'ί1 οο η - = 31 O' · tø οο cm ΐ '* cn CD tn -sj1 v £> ^ vo' sj * tø oo r- sp ιη -3 * ιη ιη ro

tn H

dp oo r · «vo oo r- σ οο σ cm σ ^ i> oo *» *, *. · »» * * · »*» W *> »* · *» v H 10 'tf LO ^ cP OO CO CM CM IT) CO "tf" tf CO <1 * «£ η H co r ·' · r - cm Η σ in ^ p οο σ in

Φ Pi CM CM CM CM rH CM CM H CM Η Η Η Η H

Eh tn •

Pn • O in Η> tf co i> cm co η- H ro "tf O tø CO '*' '* · *. ·».' · »'' '' <F η ^ 10 H r ~ cm σ" tf "tf -tf" tf in co tn hhiu φ ioh> g φ M · ^

Φ GtnoaOOOtør'- O om «3 * f" σ O O O O

j3 · Η> ιΗβιηΌνοοοσ oo O H r "σ oo H oo oo

G 1¾¾ Λ Φ Η Η H

EH cn -G

I G

0 Φ

Pi g tø O O O cm O O O θ 'O θ' Γ 'r- ~ oo

> 1 H CM CM CM CM CM CM CM H CM Η Η Η H

0 \ 0 I-I

IIH OOO OOOOO oo cm cncnooOOOcM in cm cm cm cm cm cm η h «I tn ^ XXXXXXXXXX xx X x HG'GOOOOO Ο Ο Ο Ο Ο CM O CM 00 Οι-H-HOOOOoo σ oo co oo oo oo co oo oo O Pi fi Η Η H i—)

I Η I

1 Gill I I G

rg 1 G G H G I ctjrHIHO

• rH i> AND MG Φ-Η I ^ 0 0 0 H

g-H G -G -Gen n <G -ri -G G to, G rG G

cn + J -G -G -G -G Η φ φ φ G GO) Ό 'Φ Φ G -Η Ο Ο Φ

tT> -r | φ φ φ Φ m g G -G G Φ Μ Φ * G -G P-i ΡΛ -Η N

G <G. +> +> +) -G G f-ι> m I rSG Λ> i G Φ 10 OH G G

-H G G G G G ΦΦ O cn cm -G Φ Men ο M co M GitS-GH Φ

GG-rH-H-H-H tnM GG 'Φ M AND G Φ ΟΦ -ft HH I O G

enH O!> i Η O (M ti> 1 H O HM Η Μ co G M-ι> i cm G O

· ©, φ g cn m m 'OenpGmmi ^ jG ^ i'OGGi ^ GM

3 Ό T3 Ti -H H hGG ΟΉ -Hen Ο o cm G X10 cm, G -G

a,>, · Η G G Ή 0 IG ΜΦ · Ηφ Ή Φ G ′ G −G

O iG -PM ΗΉΉ a «esm £ | ftcMΦ G

M

Φ

ρΡΦρΟΟ'ΦΦ m tn XI -H -rt Ai h g G

H

fG

48

ISLAND

DK 153800 B

Example 4

This example shows the use of various polyamides made from diamines and diacid halogens.

The polymers are prepared by dissolving the amine in a solvent, cooling the amino solution to 5-10 ° C, and then rapidly adding the diacid chloride with stirring and continuing stirring if possible for at least 1 hour. The polymer is recovered from the crumbly mass or gel by pulverizing in water in a Waring Blendor mixer, collecting on a filter and re-washing with water and then drying. The usual precautions are taken to obtain high molecular weight polymers.

The monomers used and the polymers formed appear from Table II, where the terms "PPD" and "TC1" are used for p-phenylenediamine and terephthaloyl chloride. Some specific details of the polymerization are given in Table III. When two monomers of the same type are used for the preparation of copolymers, the molar ratio of the monomers is given.

Mixtures of two solvents, hexamethylene phosphoramide (A) and N-methylpyrrolidone (B), are used for all fibers except fiber a using a 100% Ν, Ν-dimethylacetamide (DMAc) and fiber j, where equal volumes of B and DMAc are used. The weight ratio of the two solvents is given in the table as is the weight ratio of the solvent to the total monomer quantity.

Spinning solutions are prepared using sulfuric acid (99.7 to 100.0% E 2 SO 2) (a mixture of sulfuric acid and fluorosulfonic acid in the weight ratio of 1: 1 for fibers j, 1 and n and 1.15: 1 for fiber b ^) to form 46 g of polymer per 100 ml of acid (20% by weight). In some cases, the polymer used is a mixture of several different pores 49

DK 153800B

ISLAND

tions of polymer.

The spinning solutions are extruded at temperatures (spinning nozzle block) between 51 and 100 ° C (with the exception of fiber j using a temperature of 35 ° C), using an apparatus and technique as set forth in Example 1, from spinning nozzles containing holes. with a diameter of 0.051 or 0.076 mm through a layer of air (0.5 to 1.9 cm) in water (0 to 4 ° C) and the filaments are wound at a rate of 71 m per per minute for fiber j 10 to 438 m per minute. The fibers are thoroughly washed with water and dried on the coils.

The S.S.F. and filament properties are listed in Table III. The logarithmic viscosity number of fiber e and e ^ is measured at a concentration of 0.1%.

A 20/80 copolymer for fiber a, a 5/95 copolymer for fiber c, d, m and o, and a homopolymer for n and p are all listed in Table II and can be spun into fibers according to the o-friendly process .

When spinning solutions containing 56 g of polymer per

20 ml of sulfuric acid (23.4% by weight) prepared from poly (chloro-p-phenylene terephthalamide) having a logarithmic viscosity number of 4.1 dl / g is attempted spun according to this method, fibers having a filament tensile strength are obtained. of 17 gpd, ie just below the minimum specified for the invention, which results from a very high polymer concentration.

30 35

DK 153800 B

50

0) Eh P

Ό I Eh> i O Q Eh \ Eh Eh ft

M ft I Eh Eh PQ \ Eh I I

H B ft Q \ \ oj Eh Eh Eh \ P m φ I \ ft PQ hJ1 Ά Η \ H Eh PM »

SOP ft PQ <1 PQ O H UK ft CM> i ft ft \ I I I I I ll \ l H ft ft H Q Q Q P P PP ft P

O Η H Pft ft ft ft ft ft ftft O ft ft U U P ft ft ft ft ft ft ft ft ft ft 'O I -

• H C 1 I I 1 I Ό I I

g (DGG, £ lH <l) -HO il (CHCDCDftCnS + JgiHl p Η> ιΗΗΦΦϋ \ ίΰ [ΟΦ td (ti β> i> iSH N -Ρ Ό H> i— Λ oi! H) β β - 0) β - ϋ H (ti ϋ Ti Οι Η

Pi! (1) Φ Ό -P (DTJft g ϋ (d Η I T3 A Q * Λ ΛΜ \ · ΛΉ φ <ti -Ρ Κ g ft β

& ι I ft ftg U O g Ρ Η ϋ CD td \ H

φ ft I -rl td Ή N (d Φ (d ft ϋ Η β ro p \ ft λη g (dH-μ ϋ <i> i rd ω -η φ β \ I td Cd I cd H -PP rai H p • P (D β - ϋ P - AOA CD β -Ρ> i> 1 β i-i (i) ^ -P td «sp -P η ft -P idi! Β - ft <D> 1 Η -ϋ g -ϋ ϋ - OPP ft <D Ό I Ρ Η β ^ ft 3 '^ ftO'dW O -P CD ϋ H Ln CD t> l Qi NI 0 Ή I © I Η H Η IP ft g * · S β i ! β β Ρ β β Μ β g β ϋ β Φ d td cm> 1 CD ft— CD— φφ φ CD CD CD Cd CD Ο Φ-Ρ T3 H | i-) ϋ I 'β ϋ Ti Η -P Η Η-Ρ Η Η Η β Η \> ι tti β

Ο ft ftH -Η-Η> ι \> i> ι β> ι CD X ϋ (D

ftl I g Λ g β Τί β β Ό β ϋ β - Η β Η Ο -Ρ Η ft Ρ td 1 (ti Φ Η CD (ϋ -Η CD-P CD 'β> t Φ g Ιϋ ^ I OH - H i! g ϋ i! gi! i! i! Η β ϋ 3 - ft β PHtti ^ tCfftioft ft (ti ft ft ft g Φ ftH "'tf Φ φ ο ϋ ϋ" iS i X> —- i> <icd injij icti - ρ ϋ Η Η U -P * 3 * -P ft O ft * ft ft O ftp ftH ft fti! "= 1 * CD pp Η ϋ '-', β '-' ϋ '-' ϋ'- '-Η' - 'ϋ' - 'Φ' - 'Φ I' -'il '-'- PI -

0> ift> ift> iS)> ig> iP> 1-P> iiJ ft> ιϋ> h I ftO

H w HCD HCDHtd Hid Hfti H \ H-P 'HftHfi —Ή CD ΡΟΦΟΦίΡΟΦΟΦ> ig A H ft CD ft CD ftH ft td ftH ftH ft ft H ftp ftH h (d

td O O-P O-P 0¾ Oi! ΟΌ And OCD O OCD O> i Ο M

Eh ftOl OIOI Ο-ΡϋΙ OtdOPftO-POfi ftO

Η H

U Η I Ό> i I

Eh U H HO I

I Eh> i I Η Ρ Η P> i.

H I \ \ β O U O fti Ph CQ

Ο β Ό Ο H Eh Hi! ft H

Ό Eh P tti Η Λ ϋ \ ϋ -P \>,

XκϋΡ Ρ Ο Ό Ο ϋ P X

Ρ I ft -Ρ Ο H id Η Η H ft © O

0 \ φΗϋϋ> ιΡ> ιΦϋ i) Η β β - ϋ Eh Η Ο Ο OP -Ρ Ρ i! HHHOs \ rdHHH (DCD td

Ogg ίρΗΌ β tdi! td-PH ο (Dtdtd β:> ιΗ φ ϋ ΟϋΟ> ι Η ΡΗΗΦ ΟΡΝ-ΡΗ-ΡΡβ Ό iprO'O ϋ: Ν Ο β ϋ> ι ϋ Ό φ β ωββ ft β Η Φ ftO ft> ι ϋ Η Η Φ Φ Ο © .β Λ ΦΗ Φϋ ft Ό 'Ο Η Η βϋ ϋ Ο Ρ td Ρ td Η -ρ 1> η> i Η Η Η Ν φ ϋ ΦΧ Ό Ρ β β β g rQ ίΡ fdH +) -Ρ -Ρ CD Η Ο> ι η φ φ td ι ρ IUP ϋ Ρϋυβ ft gi ϋ I - td - Eh O ft Ο I Eh H | td ft ft ft ftH ^ g HIH 0 H ra I g ιό Ό η ι ι wu * β · * \ ϋ cn ϋ β \ td ν.ρ Ρ ft Οι 10 Επ -Μ * Η srrdOHH Ο (ti Ό Η ΓΗ Ρ 1 I Η Η ο Ρ Η 'Ο Ο

PP i I I I IP I eh I 1 + lpl | H

OOl O \ I O - A

CM H CMP P p PH Ρ Π3 Ρ Ό PH Η H QO

A A - »ΡΡ ft ft iJ ft H ft ft fti! “U ftO O O H ft ft ft ft O ft P ft ft ft O Eh ftp

P

Φ rQ · H * * * * * * ** * * -HftftfrQ <D4-ltPrC! u

DK 153800 B

51

Ooo vo cm r ~~ oo O vo- ^ nHco Q%. * k «*» * ** ** · * · ** j> r ^ oo cn O oo H -tf ιο uo O m ^

q CN CN ri CN H CN i-I i-IrHCNHH

vj r-OooOOOfnsfOO ^ H ^ cNO ^ cNr- cl] o I — I rOCNCN'vF'tfCOCNCNCNCOCNCN ri N n ft v • Η ^ ΓΟ'ίΐηιη'Όσΐ'ίΐ'ΟΗΓ ^ οοΓ'νοοο ^ οΗ 3 ior ' ^ 'i ^ iniriin'i> inuicoh'i o 4J ^ oooooooooooooooooo (il pi v * ^ *. · ****' *** · * ^ · **** '* ··· -

ΐζ} οΐ-νΤΟΝΟΟι — ICO'M'HHi — IHCNCNcOH'vPr-li — I

<3000000000000000000 ^ rifthinnff> 'iOcoiio ^ W5fmMhoi) N «(, i aSCinni'iominiiii / iiiiiDiii ^ in'fiiiaiot' X) nj ιησιοοιηΐ'-ιοΓΝίοοοιηιησ'ιΟΝοοιο— = t <r - io p ϋιφΡ-οοοίΗΗοοσιηΟΗΗίΝοο ^ οοσ ^ 'χΐ' ^ ΐΝ

pq ^ p ^ HCNCNCNiHi-ICNCNCNCNCNr-ICNi-li-lCNCNCN

-μ λ; in • riCCncrit ^ '^ ron ^ Lncrir'OoO'if ^ f ^ mm cm |> _j \ a »*» «**, *, *» *. * »*. *. *» * »** ^ ιίΗΐΊΐηπίΛΓΟίΊκιη 'ηιιι ^ ΓΠ ^ ιη vo ^ oo διϋ ϋ O -

H P

H

H

ft Η · m O Η Η 'ϊ H m m r ^ oo O m <n σο co in cri i £>, q • romfiofsi'iCNoonHcNvDLnfNi'iiLnrooo ^ i «id ω

EH

Φ II ri il tnu) (D (lJonmmr-oocninr '~ ooOcNCNincor''r ~ r''r ~ * © · tn <3 S fc. · * ·· * ·· *. *' ***. * · . *. »» · ** · * · * «* ·· * '·' H & r30Hooincnin'3 <oO'3, i> cocncnincriCNO '! 3 <in P-rH · Η ΰ Η Η Η Η Η Η

ο · β η Ο S

ι ι μ wm <υ <η «L ijiH CQ ΟΟΟΟΟΟΟ σιΟΟΟΟ ^ ΟΟΓ- ι 1 ¢ 3 ^> ss *. * -» · *. ** · * · * ρΐι -Η · Η rfj Η Η ι-Ι rl σι ιΗ ΟΥ Οι — Ir-li — ΙσΊι — Ιι — Ιι — ΙΟ one

m κι m O 1,1 κι κι o m O m OOOO

o. ^ ιο m ui σι in h m οι m σι oo σι \ CN \. \ \ \ \ \\ \\ \\\\

m σι in O m in m o m O m OOOO

cn \ m - = ^ in n κι m h γν h in ti EH * · α) i r-- g P E-ι Eh E-i ti Eh> i ft Eh \\ \ Eh> i \ E ^

ri El ft I E-ι Eh tQ Eh E ^ E ^ E- ^ lft! ^ E ^ E ^ I

O I \ Q \ \ ni Eh E \\ QinvoX \ P

ftQQftpQ ^ SH V * i — 1 i—! E ~ i E- * ft * ffl 5 ft ft ftft PQ <| CQUHU-Uir! K ft N (M B <ft

ftft \ irillllll \ llll \ WPQPPPPPPPftPPPPft HHPftftftftftftftftftOftftftftQ OOPftftftftftftftftftftftftftftQ

µ O)

O t — I i — I i — I i — li — li — I

Hid Id φ <4-1 i? ί · Η -r->, cj Ai, ¾ ri ti ω <U <HP

ft

ISLAND

52

DK 153800B

Example 5

This example shows polyamides made from A-B monomers, i.e. monomers having both the reactive molecule moieties in a single molecule (cf. formula unit III of claim 1).

A random copolymer (fiber a) (p-benzamide / p - phenylene-tetraphthalamide 25/75) is prepared by adding p-aminobenzoyl chloride hydrochloride to a cooled (about 6 ° C) solution of p-phenylenediamine in a mixture of 10 , 4 parts by weight of hexamethylphosphoramide and 10 parts by weight of N-methylpyrrolidone. After approx. 5 minutes and with continued cooling to approx. 6 ° C, terephthaloyl chloride is rapidly added with stirring. Stirring is continued for approx. 5 minutes. The polymer is recovered as described above. The molar ratio of the three monomers used is 1: 3: 3, respectively.

A random copolymer (fiber b) (p-benzamide / chloro-p-phenylene terephthalamide 75/25) is prepared by dissolving p-aminobenzoyl chloride and chloro-p-phenylenediamine in Ν, Ν-dimethylacetamide, cooling to ca. 11 ° C, rapid addition of terephthaloyl chloride with stirring and recovery of the polymer as indicated above after standing overnight. The monomer ratio (on a molar basis) is 3: 1: 1.

A homopolymer (fiber c) (poly (p-benzamide) is prepared by cooling Ν, Ν-dimethylacetamide to -10 ° C and rapid addition of 4- (aminobenzamido) benzoyl chloride hydrochloride (solvent / monomer weight ratio = 6, 5) with stirring After stirring for 2 3/4 hours, the mixture is neutralized with lithium carbonate and stirring is continued for a further 1 1/2 hours The polymer is recovered as described above.

The logarithmic viscosity of the polymer ranges from 4.0 dl / g (fiber b) to 5.0 dl / g (fiber a). Spinning solutions are prepared using 100 ml of sulfuric acid (99--100% I 40 g of polymer (20 wt%) for all articles except c (18 wt%).

The spinning solutions are extruded at temperatures between 37 (fiber b) and 68 ° C (fiber c) using a 53

ISLAND

DK 153800 B

apparatus and a technique as set forth in Example 1, from spin nozzles containing holes of 0.051 or 0.076 mm diameter through a layer of air (0.5-1.2 cm) in water (1-3 ° C) ), and the filaments are wound at speeds from 5,184 meters per second. per minute at fiber b to 325 meters per minute. The fibers are thoroughly washed in water and dried on the coils.

The properties are listed in Table IV.

Table IV

Filament properties Oriental

Log.viskt. Ten E Mi dpf Tou PTKS ring wine-Fiber S.S.F. Yarn (dl / g) gpd% gpd_gpd boiling 4.7 5.4 32 5.4 800 1.9 0.90 32 11.9 b 4.5 3.9 23 4.8 680 3.3 - 14 15 c 5.7 3.7 19 4.05701,00.41 11 15.8

Example 6

This example shows some variation in the spinning process. Spinning solutions of PPD-T in sulfuric acid in (99.7-20-100% I₂SO ^) are prepared and spun using an apparatus and general technique as set forth in Example 1. Some specific conditions and results are set forth in Table V.

All the spinning solutions contain 46 g of polymer per 100 ml of solvent (20% by weight) with the exception of fiber e, wherein

pC

until 38 gm is used. 100 ml (17% by weight).

All the spinning solutions are extruded at approx. 95 ° C (spinning nozzle block) with the exception of fibers e, i and j (73, 75 and 80 ° C) from a spinning nozzle with holes of 0.051 diameter with the exception of fibers c, d and j 30 (0.25, 0.20 and 0.076 mm) through a layer of air of thickness from 0.5 to 1.5 cm with a coagulation bath. The coagulation bath is water for all fibers except f, g and h to which 47.5, 54 and 70% H9 SO4 are used, respectively. For the latter three, the multifilament coming from the coagulation tube is passed under one rod in another

54 DK 153800 B

ISLAND

bath (water, 15 ° C), under yet another rod and then to the winding means. The recovery speed is from 198 to 440 m / min.

All the fibers are carefully washed and dried on the coil. The filament tensile strengths are given in Table V.

All the objects have (a) filament break extensions of 3/5 to 4/8%, (b) filament modulus of 420 (fiber e) to 850 g.p.d. (fiber f), (c) denier per. filaments of 1.1 to 2.7 with the exception of fibers c and d (10 12.4 and 10.5, respectively) and have toughness values of 0.22 to 0.69 gpd.

When the process of producing fiber e is changed by placing the front of the spinning nozzle under a water surface, the maximum recovery speed that can be used is only 27 m / min. at a spinning tensile factor of 0.6 to form 9.2 d.p.f. filaments with a tensile strength of 3.7 gpd.

In the production of fiber a, an SSF of 3 is now used, whereby filaments with tensile strengths of 23, 22 and 21 gpd are obtained when spinning tube lengths of 20 are 21.6, 10.0 and 1.27 cm. The variation in the spool tube length varies with the velocity of the water and, as a result, with the tension of the filament string.

The spinning conditions of fiber a are modified by extrusion of the spinning solution at ca. 90 ° C (from a polymer with a logarithmic viscosity number of 4.6 dl / g) through a 1 cm thick layer of air vertically into a bath of 4 ° C water, under a guide and out of the bath to a winding member at a speed of 147 m / min. and with an SSF of 3.0.

The washed and dried fibers have a filament tensile strength of 30 gpd. This procedure is repeated, replacing the air layer with a 1 cm thick layer of toluene, so that the nozzle face is dipped into toluene.

The apparent crystallite size is in each case less than 52 Λ.

35

DK 153800 B

55 r-i cd

I -P

mg

0) cd tn oi -P

• ri m G -hq)

al · C · η S -P

H ft <D P £ t3 -P-H

and nci (D-Pcd -Hen cd S S ffl A U O _ -H -P = P => ι Μ 0) = = ti X =

Μ O Η β P tn CO

cd cd -P OQ)> i O-H

> Λ ra Peg ω h>

I I

-p Ό G G 0) 0) p Λ! Ό

EXlUftincMn ^ co co H O O

cd ^ l> itn <NoJHHi-) cm cm cm ro h

h ft) -P Η P CO ft -P

i Μ P ft) O P -P • P rk oi cd σο H m O ιΗΗ'ί'οο O <D m - = --- - - - - - smoke cmO ^ o 5f c * in a "tf

G ft h H

-H p! ft-H CO G

To you

> rdO

Λ in „φ tjidi in h 5f: m nm- ^ m m Æ cd g cm cn

cd O (D

B ft · P

01

tn u β G

^ φΐη and co co lo O

Q) MOcy \ σ \ σι σι oo oo

* ϋ (DO

3¾. = = s co · ug cd r- 'cd cd cd cd cd

4J§ O OOOO O

0) -P Λί W

H

cd S ^ -p μ οι οι cd cm m ^ co .g 4J tn ^^ - ii - e ø \ o ^ ^ ii locm \ = = \ \ • H -H CD rH r ~ r- r- ^ σι oo P 01 gt) - - * ·, * cd O sf · ψ '«ρ m co cm

tnAJ rH

O and o PI -H ft i>

P

r £ JcdrQOrO (D P S 'β Η · η

• H

Pr 0

v DK 153800 B

56 t: "':

Example 7

This example shows the effect of the extrusion temperature on the process.

A spinning solution containing 46 g of polymer 5 100 ml of sulfuric acid (99% 3 SO 2) prepared from PPD-T with a logarithmic viscosity number of 5.2 dl / g is extruded using the general procedure described in Example 2 from a 100-hole spinning nozzle having a diameter of 0.05 mm through a 4.8 mm thick layer of air in water at a temperature of 5 ° C. The fibers are wound at a rate of approx.

153 m / min. with an SSF value of approx. 4.7 to 5.5. The spin solution in the boiler is kept at approx. 85 ° C. The temperature of the supply line, the spinning block and the spinning nozzle is approximately set to the extrusion temperature for each spinning.

The particular temperatures of the spinning solution - which is extruded - the logarithmic viscosity number of the fiber and filament properties are given below. The apparent crystallite size is in each case less than 52 Å.

20 Fiber_ a b c d

Extrusion temperature ° C 85 100 110-115 115-120

Onion. viskt. (dl / g) 4.8 4.5 3.9 3.2

Ten. gpd 24 22 19 11 E% 5.04.6 4.5 3.9 25 Mi gpd 484 458 414 303 dpf 1.3 1.3 1.3 1.5

Example 8

Poly (p-phenylene terephthalamide) fibers (PPD-T) 30 are made using the usual spinning conditions given in Example 2A with the exceptions given below. The fiber properties are given in Table VI for the items d-i.

The extrusion temperatures are approx. 85 ° C with the exception of fiber i, using a temperature of 95 ° C. The coagulation bath is water with a temperature

ISLAND

57

DK 153800B

of 1-4 ° C with the exception of i, where water of temperature 20 ° C is used. For the fibers d, e, f and h, a roller is used after the spinner tube. A ceramic pivot pin is used for the fibers g and i. The fibers e and h ex-5 are sprayed from spinning nozzles with 570 and 285 holes respectively. All of the spinning nozzles contain holes with a diameter of 0.05 mm with the exception of fiber f (holes with a diameter of 0.15 mm). The flow rates go from approx.

21 (fiber f) to 58 m / min. (fiber i). The spin stretching factors range from 3.5 (fiber i) to 5.2 (fiber d).

Fiber g is prepared from granules of a solidified spinde solution by melting in a screw extruder with screwdriver.

For the fibers e and h, a feed wheel 15 which is sprayed with sodium bicarbonate is used before the winding member which is sprayed with water. With the fibers e and h, the coils are stored in water and then in dilute aqueous sodium hydroxide during feeding of the extrusion means. The fibers e and h are dried on hot rollers at 120 ° C.

The fibers f and i are washed with water on the coil and placed in water for 12 hours and then dried in air at room temperature.

The fibers d and g are washed with aqueous solution of sodium bicarbonate on the coil and in the bath prior to extrusion. Fiber d is dried at 40 ° C and fiber g is dried at 75 ° C.

The yarns of the filaments identified as the fibers d, g, and h are 6-, 4-, and 2-thread shank yarns, respectively.

The filament properties of fibers d, e and h are examined on 5, 5 and 4 single filaments, respectively.

In particular, the yarns of this example can be used to make cover orders. Such yarns should have a logarithmic viscosity of at least 4.0 dl / g and yarn properties (ten / e) of at least 18 gpd and 3%. Preferably, yarn 35 used for cover orders should have a logarithmic viscosity number of

DK 153800B

ISLAND

58 4.5 dl / g and ten / E / tou (of yarn) of 20 / 3.5 / 0.35. The filaments in preferred yarns have a dpf value of less than 2.5 and preferably less than 2.0, as a greater conversion of the yarn strength into cover word strengths is thereby achieved than with a greater dpf value. Preferred yarns have tensile strength / elongation / toughness measured at 150 ° C, which is at least 70% of the value measured at 24 ° C.

10 15 20 25 30 35

DK 153800 B

59 ri (UfS'Qnr ^ rvjvDnor ^ r ^ ro rtjEnb1- · '·' * · * · * · "* · '· AJ ooooooooo tn

ri t3OOOOOOOOO (Driftr'COCOrliN O ^ OOH CnS DiiniiwininOtoinin CD

-p vDoomoiLnr ^ vDooH

£ h (¾ 0 \ ° ** ** ** * “· ** ** * * - Φ Li") ^^^^^^^ g · siritJ'cr'f'N'iri ^ iai-i

rl (PftNNtMNNCMOI (MN

• Η B &>! Ri ri ri o) ri-Htn O lo ^ OooOcnvo ririHc ^ nr-HLnooOr- '

OTD ^ ^ T ^ HHR cvir ^ R ^ H

[ri _ •> αί · ψ (> ΐΝΐηθΝ05

PM

• ΓΟιΗγΗι — li — ICNCNr — li — I

P H

• oiin ^ rimin ^ Mw

ririJfoc'oro'tfiromrnLncN

ri O A "" "" * - * * · *

(UEnCnOOOOOOOOO

-Q

ri rt3r-t ^ co <Titn <yitocnt £) H ^ Hft'iM'Tinr'CMLnMoo> ϋ] 2 & ιιΠΓ ~ σΐΊΐυην £ ΐίηιηιη ri

rH {D moicoHtoin ^ HO

Φ tr> Pri o \ °, £ j cd roncn ^ nroro '^ n ri ri ·

Eh ririT3cNoooo <y> <Nmi-iO <N

ritUA * · * · * · * ·· '·' * '·' * '

OBDlrltN ^ rinrlrlUICO

NNNNNNMNrl I o

CD I

+> tnh riin (DOcnir) '= rO' ^ cx) fNn tUri ^ 4 *> * · »*. ·» - * “** -H -ri ri O roiHCMUD ^ inr ^ LT) ri ri Ή CN r- 1 rH CN i-liHrHi-li-IO>

CO

k> ^ oriLncoo ^ oococncnr-ir ^ PL | 'Ί ^ ^ ιίη η'ίΐη'ί

• -Pri & 'CN M IN IN I · ψ f' CO M

^ \ »• 'O * -' · '·' ··· '0 [ηΛΗΐηιηιηιη ^ ιη · ί ^ ιη ri-rl> w ri

<D

XiriÆOlDCDM-lCJirri-H

• H

iri

Claims (5)

60 DK 153800B Patent claim. A method of producing polyamide fibers or films which simultaneously exhibit a tensile strength of at least 18 grams per square meter. denier, a fracture elongation of at least 3.5% for the newly spun fibers and crystalline regions having a primary apparent crystallite size, as measured in the specification, of less than 52 angstroms, by extrusion of a spinning solution through an opening over a gap in shape of a layer of inert non-coagulant liquid or gas 10 into a coagulation bath, characterized in that as a spinning solution a polyamide consisting mainly of repeating units selected from the following is used: 15 0 0 HH-C-Rn-C- (I) -N-R'-N- (II) 0 H and -CR "-N- (III) 20 where the units I and II, where they occur, are predominantly in equimolar amounts and where for at least 95 mol% of the total R, R 'and R "- groups which may be the same or different apply that R 'is selected from 1,4-25-phenylene optionally substituted with a methyl group or with a chlorine atom, and 4,4'-biphenylene, R "is 1,4-phenylene and R is as defined for R * as well as transvinylene, trans-1,4-cyclohexylene, 1,5-naphthylene, 2,6-naphthylene and 2,5-pyridylene, wherein 1.4 the phenylene groups may be interconnected with an azo group and n is 0 or 1, dissolved in sulfuric acid, the concentration of which is at least 98%, chlorosulfonic acid, fluorsulfonic acid or mixtures thereof to a polyamide concentration (C) of at least 30 g per 100 The logarithmic viscosity number of the starting polyamide is at least 2.8 dl / g measured at 30 ° C and a concentration of 0.5 g of polymer per 100 ml of solvent in concentrated sulfuric acid. 2. A process according to claim 1, characterized in that at least 75% of the R groups are 1,4-phenylene and that not more than 25 mol% of all groups of formulas I, II and III are groups of formula III . 3. A method according to claim 2, characterized in that the spinning solution fixed at 25 ° C is extruded at 40-120 ° C. Process according to claim 1, characterized in that the concentration of polyamide is 40-56 g / ml. 100 15 ml of solvent. Process according to claim 1, characterized in that the spinning solution is extruded at 70-90 ° C. 20 25 30 35