RU2285760C1 - Method of manufacturing high heat-resistant threads from copolyamidobenzimidazole with reduced degree of shrinkage - Google Patents

Abstract

FIELD: polymer production.

SUBSTANCE: invention relates to technology of manufacturing heat-resistant threads from aromatic polyamides, in particular copolyamidobenzimidazole, and can be used in manufacture of filter cloth for treating hot gases to remove toxic dust, in textile industry for sewing protective clothing for life-servers, firemen, oil and gas industry workers, and other those working in extremal situations, as well as for manufacturing carpet coverings and decorative and finishing fabrics. Method comprises synthesis of copolymer from mixture of 25-30 mol % 5(6)-amino-2-(4-aminophenyl)benzimidazole, 10-30 mol % p-phenylenediamine, and 40-60 mol % m-phenylenediamine per 100% terephthaloyl chloride in aprotic organic solvent in presence of LiCl or CaCl₂ until specific viscosity of copolymer in concentrated sulfuric acid achieves 1.2 to 2.0. p-Phenylenediamine is then added during cooling of resulting solution to 0-15°C. Thus obtained polycondensation solution is molded into water-organic bath to form thread, which is subjected to plasticizing stretching, rinsing, and drying.

EFFECT: simplified and reduced in price thread manufacturing process and reduced degree of shrinkage of thread.

5 cl, 1 tbl, 12 ex

Description

The invention relates to a technology for producing heat-resistant threads from aromatic polyamides, in particular from copolyamidobenzimidazole, and can be used to produce filter fabrics for cleaning hot gases from toxic dust; in the textile industry for tailoring protective clothing for rescuers, firefighters, oil workers, gas workers and others working in extreme situations; for the manufacture of carpets, decorative and finishing fabrics for furniture, curtains in air, land, sea transport, etc.

A known method for producing copolyamidobenzimidazole filaments, including the manufacture of a polycondensation solution in the process of polymer synthesis from a mixture of 5 (6) -amino, 2- (para-aminophenyl) benzimidazole (HCDA) and metaphenylenediamine (m-FDA) with a ratio of the latter 10-70: 30 -90 mol.% Per 100 mol.% Of terephthaloyl chloride (TPC) in an organic aprotic amide solvent in the presence of lithium chloride or calcium chloride, molding into a water-organic precipitation bath, 80-150% plasticizing extract, washing, drying and heat treatment (patent RF 2180369, 2002 )

Closest to the invention is a method for producing heat-resistant filaments from copolyamidobenzimidazole, including the manufacture of a polycondensation solution in the synthesis of copolyamide 5 (6) -amino-2- (paraaminophenyl) benzimidazole, para-phenylenediamine and a third diamine, for example 2-chloro-para-phenylenediamine, with terephthaloyl chloride in an organic aprotic amide solvent in the presence of LiCl or CaCl ₃ , molding is carried out in an aqueous-organic precipitation bath. The resulting thread is subjected to plasticization drawing, washed, dried, heat treated and thermally drawn in the temperature range 350-410 ° C (RF patent 2017866, 1994).

One of the main requirements for fabrics for sewing filter bags or special clothes is a low degree of heat shrinkage. However, shrinkage at a temperature of 300 ° C of the most economical yarns according to the known method (RF patent 2180369, 2002), containing a minimum number of links of expensive diamine HCDA (for example, 20-30 mol.%) And not subjected to labor-intensive, requiring large energy costs technological operations for their heat treatment, reaches 20-30%. This is unacceptable by fire safety standards, according to which the tissue shrinkage rate at 300 ° C should not exceed 5%. In the known method, heat treatment of threads not only eliminates heat shrinkage, but also leads to a significant increase in their cost.

The objective of the invention is to simplify the process for the production of copolyamidobenzimidazole yarn and reduce its cost by reducing the number of stages of the process, i.e. refusal to carry out the operation for heat treatment of the thread or carrying out this stage, but at lower temperatures than for known ones, as well as reducing the degree of heat shrinkage of the threads.

The problem is solved due to the fact that the method involves the preparation of a 9-15% polycondensation solution during synthesis from a mixture of HCDA and m-PDA, in which para-phenylenediamine (p-PDA) is added, with terephthaloyl chloride in an organic aprotic amide solvent for example dimethylacetamide (DMAA) or N-methylpyrrolidone, in the presence of lithium chloride or calcium chloride. The molar content of diamines per 100 mol.% DHA is:

GTsDA 25-30

m-FDA 40-60

p-FDA 10-30

and the synthesis is carried out to obtain a specific viscosity of the polymer in concentrated sulfuric acid from 1.2 to 2.0. The molding is carried out in an aqueous-organic bath, preferably containing 50-65 wt.% Amide solvent, at 18-40 ° C.

Then the thread is subjected to plasticization drawing by 80-150%, washed and dried. The polymer has the following chemical structure:

where m = 25-30, n = 40-60, P = 10-30 and m + n + p = 100.

The introduction of p-PDA hard links, the cost of which does not exceed that for m-PDA, leads to an increase in the overall rigidity of aramid macromolecules and a decrease in the degree of thermal shrinkage of the yarn based on this polymer with increased rigidity of molecular chains.

The mechanical properties of the strands are little dependent on the composition of the copolymer at the above boundaries, but the permissible thermal shrinkage of freshly formed strands is observed only when the content of p-FDA units in the macromolecules is 15 mol % and higher. Therefore, for filaments from a copolymer with a p-FDA unit content of less than 15%, heat treatment is required. The upper limit of the amount of p-PDA is due to the solubility of the copolymer, the increase in viscosity and the degree of structuring of solutions. With its content of more than 30 mol%, it is not possible to obtain spinning solutions with a concentration of more than 9% with the necessary combination of the specific viscosity of the polymer and the viscosity of the spinning solution, while the use of 25-30 mol% of HCDA and the rest of m-PDA in the diamines is unchanged. In addition, it is known that the processing of low-concentrated polymer solutions is not economically feasible. To obtain low-shrink filaments with an acceptable strength of 30-50 cN / tex without expensive heat treatment and hardening operations, the specific viscosity of the polymer should be 1.2-2.0, and the solution viscosity 75-210 Pa · s.

For processing into yarns, both acidic solutions with HCl content and neutralized by the introduction of calcium oxide (CaO), lithium hydroxide (LiOH) or other bases after completion of the polymer synthesis are used. Only part of HCl (80-85%) of its total content can be neutralized, i.e. the so-called free HCl, since the rest is firmly bound to the benzimidazole polymer cycles having base properties.

The formation of the thread is carried out wet through a die with openings of 0.07-0.1 mm in diameter to a precipitation bath containing a 50-65% solution of DMAA or N-methylpyrrolidone in water, at room temperature 18-24 ° C or raised to 40 ° C with a winding speed on a rotating reel of 15-25 m / min. Spinning hood is from minus 40 to plus 40%, and plasticizing hood, conducted in air in the entrained bath layer with a thread, from 80 to 150%. After washing from the solvent, salt and hydrochloride, neutralizing the hydrochloride residues in the yarn with an alkaline reagent, drying and twisting, the physical and mechanical properties of the yarn are determined.

The viscosity of the spinning solutions is determined by the duration of the fall of the control steel ball in the medium of the solution at 20 ° C.

As a characteristic of the molecular weight of the polymers, the specific viscosity is used, which is determined on a Ubbelode capillary viscometer for solutions of 0.5 g of dry polymer in 100 ml of 96% sulfuric acid at 20 ° C.

The linear density of the filament is determined by weighing 1 m of filament, and of single fibers by the resonance method, at a moisture content of about 5% for freshly formed and about 3% after heat treatment.

The strength of the threads (specific breaking load) and elongation at break is determined on a tensile testing machine using a clamping length of 250 mm according to generally accepted methods.

If it is necessary to increase the strength characteristics, it is possible to conduct heat treatment of the threads. Heat treatment can be carried out in a free state at 320-350 ° C for 15-30 minutes (the thread is wound on glass spools) in an inert nitrogen atmosphere or in vacuum, or by passing a 500 tex linear density thread through an electrically heated tube with a temperature of 320-350 ° C for 20 seconds in air with a minimum tension provided by stretching the thread by 5%.

The determination of heat shrinkage of the thread is carried out by keeping 1 m of the thread in the cabinet at 300 ° C for 5 minutes.

The invention is illustrated by the following examples.

Example 1

The synthesis of a polymer from a mixture of diamines 5 (6) amino, 2- (para-aminophenyl) benzimidazole (HCDA), meta-phenylenediamine (m-PDA) with terephthaloyl chloride (TPC) with a unit ratio of 30:55:15, respectively, in the medium is described N-methylpyrrolidone with CaCl ₂ addition and spinning from the resulting 11.0% solution.

120 ml of dry N-methylpyrrolidone containing 3.0% calcium chloride, 4.060 g (0.01810 mol) of HCDA, 3.589 g (0.03319 mol) of m-PDA and 0.979 g (0.00905 mol) of p -FDA. The total amount of moisture in the reaction mixture is 0.03-0.04%. It should not exceed 0.05%.

After cooling to 10-15 ° C, 9.745 g (0.0480 mol) of TPC (80% of the equimolar) are added to the resulting suspension of diamines with a partial or complete transition to the p-PDA solution after cooling to 10-15 ° C. The solution becomes transparent at the initial stage of TPC dosing and quickly heats up to 30-35 ° C as a result of the exothermic synthesis reaction. After 15-30 minutes, the remaining amount of TPC is added in parts with continuous stirring, i.e. 2.506 g (0.01234 mol), maintaining the temperature of the solution in the range of 30-35 ° C, after which stirring was continued for another 2 hours. Get the finished solution with a viscosity of 85 PA · s and a specific viscosity of the polymer of 1.30.

A polycondensation 11.0% solution with a content of 2.6% CaCl ₂ and 2.9% HCl is used to spin the filament without neutralizing the hydrochloride in it, after filtration and dehydration. Molding is carried out in a wet manner through a die on 100 holes with a diameter of 0.07 mm. The temperature of the spinning solution and precipitation bath 18-22 ° C. As a precipitation bath, a 50% solution of N-methylpyrrolidone in water is used. The flow rate of the solution to the die is 4.30 g / min. Spinneret drawing of the jet in the precipitation bath is negative, equal to minus 40%, plasticizing stretching of the thread by 150%, it is carried out in air in the bed carried out with the thread of the precipitation bath at normal temperature between two biscuits rotating at different speeds. The thread is partially washed with water and taken at a speed of 15 m / min on a rotating perforated bobbin. On the bobbin, the thread is finally washed from solvent, salt and hydrochloride, neutralize the remaining hydrochloride with a NaOH solution, washed from excess alkali, dried at 80 ° C and twisted to 120 torsions per 1 meter. The yarns are obtained with the following indicators: T / P / Y = 33.1 / 36.5 / 11.0 where, T - linear density, tex; P - strength, cN / tex; Y - elongation at break,%.

Part of the thread is heat treated at 350 ° C. The properties of the threads, as well as the properties of the polymer solution are shown in the table. The heat shrinkage of a freshly formed yarn is 5%, and after heat treatment a non-shrink yarn is obtained. Heat treatment provides an increase in yarn strength by 1.5 times (from 36.5 to 55 cN / tex), but with a decrease in elongation at break from 11 to 7%. As a result of heat treatment, the equilibrium moisture absorption also decreases from 10-12% for a freshly formed yarn to 6-8% (under conditional conditions at 20 ° C and 65% relative humidity).

Examples 2 and 3.

The formation of filaments from 11% solutions obtained by synthesizing a polymer from a mixture of diamonds HCDA, m-PDA and p-PDA with terephthaloyl chloride with a ratio of 25:55:20 mol. %, respectively, in DMAA medium supplemented with LiCI with hydrochloride in solution (Example 2) or neutralized with LiOH reagent (Example 3).

The synthesis of the polymer and spinning are carried out according to example 1 with the exception of changes in some parameters.

120 ml of DMAA and 3.27 g of lithium chloride (2.8%) are then charged into a glass reactor, then 3.131 g (0.01396 mol) of HCDA, 3.321 g (0.03071 mol) of m-PDA and 1.208 g (0.01117 praying) p-FDA. The suspension is cooled, after which 50% of the equimolar amount of terephthaloyl chloride is added with vigorous stirring.

After 30 minutes, the remaining terephthaloyl chloride is added in portions, the total amount of which is 11.337 g (0.05584 mol), maintaining the temperature of the solution in the range of 30-35 ° C. At the end of the TPC dosage, stirring is continued even after 2 hours. The hydrochloride formed as a result of polymer synthesis is neutralized with 100% lithium hydroxide, adding LiOH gradually so that the temperature of the solution does not exceed 50 ° C. Amount of LiOH 2.674 g (0.1147 mol). The resulting solution with a polymer concentration of 10.8%, 5.8 LiCl and 1.5% water is used to form the filament (example 3), like a similar solution after the synthesis of the polymer under the same conditions, but without the stage of neutralization of the hydrochloride (polymer concentration 11 , 0%, 2.4% LiCl and 3.0% HCl (Example 2): Molding is carried out through dies for 200 holes with a diameter of 0.07 mm with a solution feed of 4.30 g / min with a die drawing of about 40% and optimal plasticizing hood, equal to 100%. The properties of the solutions and indicators of the threads are shown in the table. Freshly formed thread is quite high strength indices of 42-48 cN / tex, apparently due to the increased specific viscosity of the polymer 1.72-1.75.

Example 4

The polymer synthesis with a ratio of 30:50:20 mol units is described. % from a mixture of diamines HCDA: m-PDA: p-PDA with terephthaloyl chloride in DMAA with CaCl ₂ addition and spinning of the obtained 10.8% solution after neutralization of free hydrochloride with calcium oxide in it.

100 l of DMAA (humidity 0.02-0.035%) are poured into the reactor, 1.100 kg of CaCl ₂ are loaded after drying in vacuum at 200 ° C with a moisture content of not more than 0.05% (1.15% CaCl ₂ in DMAA) and dissolution is carried out for 30 minutes in an inert nitrogen atmosphere at 20 ° C. Continuing stirring, load the diamines: 3,010 kg (13,423 mol) of HCDA, 2,419 kg (22,372 mol) of m-PDA and 0.968 kg (8,951 mol) of p-PDA, and cool the mixture to 15-17 ° C, then in it after 30 minutes from the beginning of the loading of diamines, a portion of terephthaloyl chloride is charged in an amount of 75% of the polymer necessary for the synthesis (6, 8 kg). The temperature of the medium rises due to the exothermic reaction, however, the reactor is cooled and the subsequent dosage of terephthaloyl chloride is carried out so that it does not exceed 35-40 ° C and is not lower than 25 ° C. 30 minutes after the first loading of terephthaloyl chloride, the remaining amount is added in portions with an interval of 15 minutes, without adding more terephthaloyl chloride if the required solution viscosity is reached. A total of 9.084 kg (44.745 moles) of TPH is taken, i.e. an amount close to equimolar with respect to diamines. An 11.0% polymer solution containing the hydrochloride is obtained.

After 2 hours of stirring, the hydrochloride is neutralized by adding to the solution of calcium oxide in four approximately equal portions with an interval of 30 minutes, cooling the reactor so that the temperature of the solution does not exceed 40 ° C. In total, 2.133 kg (38.036 mol) of CaO are used, calculated on the neutralization of 85% HCl, given that the remaining amount of HCl is firmly bound to the benzimidazole polymer cycles, forming a salt form.

10.8% polycondensation solution containing 4.7% CaCl ₂ , 0.6% water and 0.4% HCl bound to the polymer, with a viscosity of 75 Pa · s and a specific viscosity of 1.23 polymer after filtration and dehydration used for forming filaments by wet method through a die 2400 holes with a diameter of 0.07 mm in a precipitation bath containing a 50% solution of DMAA in water and about 2% CaCl ₂ at room temperature (18-24 ° C). The filing of the solution on the die 67.0 g / min. Spinneret drawing of the jet is close to 15%, and the plasticizing drawing of the thread, which is carried out in air in a layer of a precipitation bath carried away with the thread between two Pentavils rotating at different speeds, is 80%. The exit speed of the thread after plasticization drawing 14.5 m / min. This is followed by washing the yarn, treating with dilute NaOH to neutralize the HCl bound to the polymer, washing from excess alkali that are carried out in successively installed troughs, drying the yarn at 100-110 ° C on a drum dryer and accepting it on a rotating cartridge without twisting at a speed of 15, 0 m / min Get a thread of linear density 500 tex with the following indicators for single fibers.

T / P / Y = 0.22 / 30 / 11.0.

The thermal shrinkage of the obtained yarn for 5 minutes at 300 ° C is 4.05%.

To conduct heat treatment, the thread is passed through an electric heated tube with a temperature of 320 ° C and a residence time in the zone with an elevated temperature of 20 seconds and with a hood by 5%. Get heat-treated thread with indicators for single fibers.

T / P / Y = 0.21 / 40 / 8.0.

Thermal shrinkage of the filament is 2.7%.

Example 5 (comparative).

Synthesize a polymer with a ratio of units of 30:70 mol. % from a mixture of diamines HCDA: m-PDA with terephthaloyl chloride, which is described in patent RF 2180369, under similar conditions as in example 4. Get a 10.8% solution with a viscosity of 65 PA · s and a specific viscosity of the polymer of 1.25 after neutralizing the free hydrochloride in it (85% of the total HCl content), which is used for wet spinning of threads through a die on 2400 holes with a diameter of 0.07 mm with a solution feed to the die of 67.0 g / min. The molding is carried out in the same way as described in example 4, with a plasticization extract by 110%.

The exit speed of the thread after plasticization drawing 14.5 m / min and the speed of reception of dry threads 15.0 m / min.

A yarn of linear density 510 tex is obtained with the following indices for single fibers.

T / P / Y = 0.22 / 34.0 / 14.

The heat shrinkage of the filament is 15.0%, it decreases to 5% after heat treatment under the conditions described above at a temperature in an electrically heated tube of 350 ° C. The properties of the fiber after heat treatment T / P / U = 0.21 / 40.5 / 10.

Examples 6 and 7.

Spinning from a 10.8% polymer solution obtained in example 4, a composition of 30:50:20 mol. % HCDA: m-PDA: p-PDA with terephthaloyl chloride, carried out according to example 1 with the exception of changes in some parameters.

The molding of the threads is carried out wet with a temperature of the solution and precipitation bath of 20-22 ° C, which is used as a 50 and 65% solution of DMAA in water (examples 6 and 7, respectively), through a die for 100 holes with a diameter of 0.1 mm. The flow rate of the solution to the die is 7.50 g / min. Spinneret drawing of the jet is close to 30 and 15%, and the optimal plasticizing drawing of the thread is 110 and 140% in examples 6 and 7, respectively. The thread is taken onto a bobbin at a speed of 25 m / min and the same treatments are carried out on a bobbin as in Example 1.

The yarns with properties T / P / Y = 34.0 / 35.0 / 12 and 33.5 / 37.0 / 11 and heat shrinkage of 4.2 and 4.8% are obtained (see table).

Example 8

The synthesis of the polymer with a ratio of 30/50/20 mol% is described. % of diamonds HCDA: m-PDA: p-PDA with terephthaloyl chloride with a specific viscosity of the polymer η _beats = 2.0 in DMAA with CaCl ₂ addition and neutralization of free hydrochloride with CaO reagent and spinning from the obtained 10% solution.

The polymer synthesis and spinning are carried out according to example 1, with the exception of changes in some parameters. For the synthesis of the polymer take 120 ml of dry DMAA with a moisture content of not more than 0.03%, 2.91 g of CaCl ₂ (2.5% in a solution of DMAA), 3.353 g (0.01495 mol) of HCDA, 2.695 g (0.02492 mol ) m-PDA, 1.078 g (0.00997 mol) of p-PDA and 10.119 g (0.04984 mol) of terephthaloyl chloride. The hydrochloride formed as a result of polymer synthesis is neutralized with calcium oxide by 85%, i.e. neutralize free hydrochloride, adding it gradually so that the temperature of the solution does not exceed 50 ° C. A total of 2.375 g (0.04235 mol) of CaO is added. Get ready 10.0% solution containing 5.6% CaCl ₃ , 0.6% water and 0.4% bound to the polymer HCl, with a viscosity of 150 Pa · s and a specific viscosity of polymer 2.0, which is used for forming the thread.

The filament is formed in a wet manner through a die on 100 holes with a diameter of 0.08 mm. As a precipitation bath, a 50% solution of DMAA in water is used at ordinary temperature (18-24 ° C). The flow rate of the solution to the die is 4.30 g / min. Spinneret drawing of jets is close to minus 10%, and plasticizing drawing of threads is 110%. The thread is taken onto the bobbin at a speed of 15 m / min and the bobbin is subjected to the same treatments as in Example 1. A thread of linear density 30.1 tex is obtained, the properties of which are shown in the table (including the thread after heat treatment at 350 ° C) . Heat shrinkage of a freshly formed yarn 4.5%.

Example 9

The synthesis of the polymer with a ratio of 30/50/20 mol% is described. % of diamines HCDA: m-PDA: p-PDA with terephthaloyl chloride in DMAA with CaCl ₂ addition and neutralization of free hydrochloride with CaO reagent and spinning from the resulting 15% solution.

The polymer synthesis and spinning are carried out according to example 1, with the exception of changes in some parameters.

120 ml of dry DMAA and 2.91 g of CaCl ₂ (2.5%) are then charged into a glass reactor, then 5.483 g (0.02445 mol) of HCDA, 4.406 g (0.04074 mol) of m-PDA and 1.763 g (0, 01630 mole) p-FDA. The suspension is cooled, after which 50% of the equimolar amount of terephthaloyl chloride is added with vigorous stirring. After 30 minutes, the remaining terephthaloyl chloride is added in portions, the total amount of which is 16.544 g (0.08149 mol), maintaining the temperature of the solution in the range of 30-35 ° C. Stirring is continued and after 2 hours, the hydrochloride formed by the synthesis of the polymer is neutralized with 85% calcium oxide, adding it gradually so that the temperature does not exceed 50 ° C. A total of 3.885 g (0.06927 mol) of CaO is added. Get ready 15% solution containing 7.1% CaCl ₃ , 0.8% water and 0.6% bound to the polymer HCl, with a viscosity of 122 Pa · s, the specific viscosity of the polymer 1, 2, which is used to form the thread at a temperature of at least 40 ° C, since below this temperature a precipitate precipitates from the solution.

The filament is formed in a wet manner through a die on 100 holes with a diameter of 0.08 mm. As a precipitation bath, a 50% solution of DMAA in water with a temperature of 40 ° C is used. The solution is supplied to a die of 4.30 g / min. Spinneret drawing of the jet is close to minus 10%, and plasticizing drawing of 110%. The thread is taken onto a bobbin at a speed of 15 m / min and the bobbin is subjected to the same treatments as in Example 1. A thread of linear density 45.2 tex is obtained, the properties of which are shown in the table (including the thread after heat treatment at 350 ° C) . Heat shrinkage of a freshly formed yarn 3.9%.

Examples 10 and 11.

Describes the synthesis of the polymer with a ratio of 25/45/30 units (example 10) and 30/40/30 mol. % (example 11) from diamines HCDA: m-PDA: p-PDA with terephthaloyl chloride in DMAA medium with CaCl ₂ addition and neutralization of free hydrochloride with CaO reagent, spinning from the obtained 11% solutions.

The synthesis of the polymer and the formation of the threads is carried out according to example 1 with a change in the load of monomers corresponding to the new composition of the polymers. For the synthesis of the polymer with a ratio of units 25/45/30 mol. % take 120 ml of DMAA, 2.91 g of CaCl ₂ (2.5%), 3.203 g (0.01428 mol) of HCDA, 2.780 g (0.02571 mol) of m-PDA and 1.854 g (0.01714 mol) of -FDA and 11.601 g (0.05714 mol) of terephthaloyl chloride, as well as 2.804 g (0.0500 mol) of CaO to neutralize free HCl. The neutralization is carried out as described in example 8. The properties of the prepared 11% solution containing 6.1% CaCl ₂ , 0.65% water and 0.4% polymer bound HCl and freshly formed filament linear density 33.1 tex and heat-treated at 350 ° C threads are shown in the table. The parameters for forming the yarn are the same as in Example 8. The heat shrinkage of the freshly formed yarn is 0.05%.

A similar 11% polymer solution, but with a link ratio of 30:40:30 mol. % of the same monomers in DMAA with CaCl ₂ gives a precipitate after synthesis of the polymer when it is cooled to room temperature. Therefore, its processing is possible at elevated temperatures, and at 18-20 ° C, a solution of 9% concentration is stable. To synthesize a polymer to produce such a solution, 120 ml of DMAA, 2.91 g of CaCl ₂ (2.5%), 2.974 g (0.01326 mol) of HCDA, 1.912 g (0.01768 mol) of m-PDA, 1.434 g ( 0.01326 mol) p-PDA and 8.972 g (0.04419 mol) of terephthaloyl chloride, as well as 2.106 g (0, 3756 mol) of CaO to neutralize the free HCl therein (Example 11). As a result of molding with the same parameters as in example 8, a filament of linear density of 27.1 tex is obtained. The properties of a 9.0% solution with a content of 5.3 CaCl ₂ , 0.5% water and 0.4% HCl bound to the polymer and indicators of freshly formed and heat-treated at 350 ° C threads are shown in the table. Thermal shrinkage of a freshly formed thread does not exceed 0.5%. The thread is most durable after heat treatment (91.6 cN / tex).

Example 12

The synthesis of the polymer with a ratio of units 30/60/10 mol. % of diamines HCDA: m-PDA: p-PDA with terephthaloyl chloride in DMAA medium with CaCl ₂ addition and neutralization of free hydrochloride with CaO reagent, spinning from the obtained 11% solution.

The polymer synthesis is carried out according to example 1 with a change in the load of monomers corresponding to the new composition of the polymers.

As a result of polymer synthesis and spinning, yarns with the same parameters as in Example 8, a yarn with a linear density of 33.2 tex are obtained. The properties of the polymer and the performance of freshly formed and heat-treated at 350 ° C threads are shown in the table.

Thermal shrinkage of a freshly formed yarn is 6.9%. It is higher than permissible (5%). Therefore, such a thread can be used for the production of textile products only after its heat treatment.

Properties of solutions and filaments based on polymers from a mixture of diamines HCDA, m-PDA and p-PDA and terephthaloyl chloride Example No. The ratio of GCDA / m-FDA / p-FDA, mol. % The concentration of the solution,% The viscosity of the solution, PA · s The specific viscosity of the polymers Properties of Freshly Formed Yarn Heat Treatment Thread Properties one 2 3 four 5 6 7 8 9 10 eleven 12 one 30:55:15 11.0 85 1.30 33.1 36.5 11.0 5,0 32,0 60.0 7.0 2 25:55:20 11.0 210 1.72 33.1 48.0 14.0 4,5 32.3 72.0 9.0 3 25:55:20 10.8 140 1.75 32,5 42.0 12.0 4,5 31.3 68.0 8.9 four 30:50:20 10.8 75 1.23 0.22 * 30,0 11.0 4,5 0.21 * 40,0 8.0 5 30:70 (for comparison) 10.8 65 1.25 0.22 * 34.0 14.0 fifteen 0.21 * 40.5 10.0 6 30:50:20 10.8 75 1.23 34.0 35.0 12.0 4.2 32,5 58.0 7.0 7 30:50:20 10.8 75 1.23 33.5 37.0 11.0 4.8 32,0 60.0 8.0 8 30:50:20 10.0 150 2.0 30.1 54.0 11.0 4,5 29.0 75.0 8.5 9 30:50:20 15.0 122 1.20 45,2 32,0 8.7 3.9 44.0 57.3 8.8 10 25:45:30 11.0 116 1.48 33.1 44.5 12.6 0.05 32,0 50,0 6.8 eleven 30:40:30 9.0 124 1.74 27.1 41.1 12.0 0.5 26.3 91.6 6.3 12 30:60:10 11.0 60.0 1.20 33,2 35.0 17.0 6.9 32,4 60.0 12.5 * The indicators of single fibers in a thread of linear density 500 tex are given.

Claims (5)

1. A method of producing heat-resistant filaments from copolyamidobenzimidazole with a reduced degree of heat shrinkage, comprising the manufacture of a polycondensation solution during the synthesis of a copolymer from a mixture of 5 (6) amino-2- (para-aminophenyl) benzimidazole, para-phenylenediamine and third diamine with terephthaloyl chloride in organic an aprotic amide solvent in the presence of LiCl or CaCl ₂ , molding into an aqueous-organic precipitation bath, plasticizing hood, washing and drying, characterized in that methane is used as the third diamine α-phenylenediamine in the following molar ratio of dimines per 100 mol.% terephthaloyl chloride: 5 (6) -Amino-2- (para-aminophenyl) benzimidazole 25-30 Meta-phenylenediamine 40-60 Para-phenylenediamine 10-30 and the synthesis is carried out to obtain a specific viscosity of the copolymer in concentrated sulfuric acid from 1.2 to 2.0. 2. The method according to claim 1, characterized in that the polycondensation solution is neutralized by the introduction of calcium oxide or lithium hydroxide. 3. The method according to claim 1, characterized in that dimethylacetamide or N-methylpyrrolidone is used as the organic aprotic amide solvent. 4. The method according to claim 1, characterized in that the molding is carried out in a precipitation bath containing 50-65 wt.% Amide solvent at 18-40 ° C. 5. The method according to claim 1, characterized in that after drying the thread is additionally heat treated at 320-350 ° C for 0.3-30 minutes