RU2409710C1 - Method of producing fibres, threads, films from heterocyclic aromatic polyamidoimides, containing benzimidazole fragments, and fabric based on said threads - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: method involves preparation of two solutions of a mixture of 5(6)-amino-2(para-aminophenyl)benzimidazole with 5(6)-amino-2(para-iminoquinone)benziimide in dimethylacetamide which contains lithium chloride, and then addition of paraphenylenediamine and an equimolar amount of terephthaloyl chloride to the first solution, and to the second solution - an equimolar amount of a dianhydride of pyromellitic acid. Said solutions are mixed at room temperature until formation of a spinning solution with dynamic viscosity of 300-600 P and concentratio of 3.5-4.0 wt %. The solution is filtered, vacuum treated and formed in a water-salt or water-alcohol settling bath, dried and thermally treated in free state. Industrial fireproof ballistic fabric is then produced from the obtained fibres. Threads obtained according to the invention have elementary fibre diametre higher than 10 mcm, rupture resistance not lower than 280 cN/tex and relative elongation of 3.8-4.5%.

EFFECT: invention enables to obtain fibres, threads, films with high elasticity while retaining good strength properties.

2 cl, 3 tbl, 4 ex

Description

The invention relates to a technology for producing molded products in the form of fibers, threads or films made of synthetic polymers, in particular from heterocyclic aromatic polyamidoimides containing benzimidazole fragments, and can be used for the production of special-purpose fabrics or composite materials.

1. A known method of producing a thread from a heterocyclic aromatic polyamide, including the synthesis of aromatic copolyamide benzimidazole based on 5 (6) amino-2-para-aminophenylbenzimidazole, para-phenylenediamine, terephthaloyl chloride with preliminary dissolution of diamines, cooling the solution to 15-20 ° C, adding first, 80-92% of the equimolar ratio of terephthaloyl chloride, and then after stirring for 30 minutes, by gradually introducing the remaining amount of terephthaloylchloid by cooling. The resulting 3.5-5.0% solution after filtration and deaeration is formed into a precipitating water-dimethylacetamide bath with a negative die drawing, subjected to orientational drawing, drying and heat treatment under vacuum at 340-360 ° C (RU 2277139 C1, published. 05/27/2006).

The resulting filaments have a strength of up to 270 gf / tex, breaking stress in microplastics up to 600 kgf / mm ² .

However, in the above analogue, the threads have a strength of not higher than 270 gf / tex and an elongation in the range of 2.5-3.0%.

2. A known method for producing a heat-resistant polyimide film from a polyimide amide salt based on various aromatic tetracarboxylic acid dianhydrides, including pyromellitic dianhydride, by pouring a solution onto a substrate, immersion in a precipitation bath, drying and heat treatment (US Pat. No. 6,716,270, published April 6, 2004).

The polymer from which the film was obtained by the specified method contains only polyimide groups, and the film is intended for the manufacture of separation membranes.

3. From the patent of the Russian Federation 2352595, publ. 04/20/2009, a method for producing polyimide fibers from a polycondensation solution of polyamide acid is known. For the polycondensation medium in an amide solvent, a mixture of diamines ¹ -diaminotrifenilamina 4.4 and 5 (6) -amino-2-p-aminofenilbenzimidazola dianhydride and a mixture of 3.3 ¹ 4.4 ¹ -benzofenontetrakarbonovoy acid dianhydride of pyromellitic acid.

According to this method, at the polycondensation stage, a mixture of 5 (6) -amino-2-para-aminophenylbenzimidazole and pyromellitic dianhydride is introduced to prevent gelation and stabilize the technology.

4. Known fabric for the manufacture of ballistic resistant products made of threads formed from a dope of an aromatic copolymer of dibasic terephthalic acid chloride and diamines of benzimidazole and p-phenylenediamine (patent 2337304, published. 10.27.2008).

According to the said patent, the polymer from which the thread is made contains only polyamidebenzimidazole groups, and the thread has a diameter of elementary fiber of not higher than 10 μm.

5. A known method for producing heat-resistant fibers or films from polyamidimides obtained by high-temperature polycondensation using aromatic dicarboxylic acids or mixtures thereof and a mixture of trimellitic and pyromellitic acid dianhydrides (SU 359836 A, published. 16.01.1973). These fibers have a strength of 45-62 gf / tex and an elongation of 5.5-11.8%.

According to the method for producing heat-resistant fibers, pyromellitic dianhydride is introduced into a mixture of diisocyanates to increase the solubility of the dope, while the filaments have a low strength at the level of 45-62 gf / tex.

The technical problem to which this invention is directed is to obtain fibers, filaments or films having increased elasticity while maintaining high strength characteristics, in a technically safe way.

The stated technical problem is achieved by copolycondensation in an amide-salt system based on dimethylacetamide of reactive bifunctional compounds of a mixture of aromatic diamines and aromatic acid dianhydrides.

As aromatic diamines, a mixture of 5 (6) -amino-2 (para-aminophenyl) benzimidazole (DAFBI) with 5 (6) -amino-2 (para-iminoquinone) benzodiimide (AIPDI) and p-phenylenediamine (PFDA) is used.

As aromatic acid dianhydrides, terephthalic acid dichloride (DCA) and pyromellitic dianhydride (DPA) are used.

Polycondensation is carried out in a system of dimethylacetamide cooled to 10 ° C, containing lithium chloride up to 4 wt.%. The polycondensation process consists of the stages of obtaining a solution of polyamides and a solution of polyamido acids, mixing them.

Obtaining a solution of polyamides involves sequentially dissolving a mixture of DAPBI and AIPDI in a crystalline state in a mass ratio of 55: 45-10: 90 and after completely dissolving the mixture, adding PFDA in an amount of 0-0.3 mol fractions relative to a mixture of DAPBI + AIPDI and adding an equimolar amount of DCA relative to mixtures of diamines.

Obtaining a solution of polyamido acids involves sequentially dissolving a mixture of DAPBI and AIPDI in a crystalline state in a mass ratio of (55:45) - (10:90) and after complete dissolution of the mixture, the addition of an equimolar amount of DPC relative to the mixture of diamines.

The preparation of the dope is carried out by introducing 5-10 volume fractions of a polyamido acid solution into 90-95 volume fractions of a polyamide solution at room temperature.

The spinning solution has a polymer concentration of 3.5-4.0 wt.% And a viscosity of at least 300 P.

The resulting spinning solution is filtered, dehydrated and sent for spinning in water-salt or water-alcohol baths. The resulting fibers, filaments and films are subjected to plasticization drawing of no more than 20%, washed, dried at a temperature of no higher than 120 ° C and heat treated in a free state at a temperature of no higher than 350 ° C. The resulting polymer is characterized by the presence of polyamide, polyimidol, polyimide groups based on benzimidazole.

The product obtained according to the invention contains the named fragments identified by the method of IR polarization spectroscopy by the fluctuations of the characteristic absorption bands (table 1).

No. Kind of radical Type of communication Polarization Frequency, cm ^-1 one

σ 1651 π 1600 2

π S 1773 σ aS 1723 π 1600 3

σ 3300-3360 Ar π 1600 four

σ 3300-3350

π 3200-330 5

Ar π 1600 6

σ 3200-3300 7

π 1630 Ar π 1600 8

π 1630 Ar 9

π 1630

π 3600 Ar π 1600

The yarns obtained according to the invention have a fiber diameter of more than 10 μm, a tensile strength of at least 280 cN / tex and an elongation of between 3.8-4.5%.

From the obtained threads or yarns based on the claimed product are made fabrics with high strength, heat-resistant and ballistic properties. The invention is illustrated by examples.

Example 1. 95 g of lithium chloride are dissolved in 2.85 L of dimethylacetamide (DMAA). The obtained amide-salt solvent is cooled to T = 10 ° C and a mixture of DAFBI and AIPDI is added to it at a ratio of 55:45 in the amount of 36.18 g. After complete dissolution, 32.62 g of DCA are added to the solution.

To prepare a second solution, 5 g of lithium chloride is dissolved in 0.15 L of dimethylacetamide (DMAA). The obtained amide-salt solvent is cooled to T = 10 ° C and a mixture of DAFBI and AIPDI is added to it at a ratio of 55:45 in the amount of 1.90 g. After complete dissolution, 1.95 g of DPC is added to the solution. The solutions are mixed at room temperature and a spinning solution is obtained with a polymer concentration of 3.85% by weight and a viscosity of 450 P. After filtration and evacuation, molding is carried out through a die 200 by a wet method. The resulting yarn is drawn with a spun-drafted hood of -20%, dried at a temperature of 120 ° C and heat treated at a temperature of 350 ° C. Data on the properties of the finished yarn are shown in table 2.

Example 2. 95 g of lithium chloride are dissolved in 2.85 L of dimethylacetamide (DMAA). The obtained amide-salt solvent is cooled to T = 10 ° C and a mixture of DAPBI and AIPDI is added to it at a ratio of 15:85 in the amount of 26.88 g. After complete dissolution, 10.4 g of PFDA is added to the solution, then 34 , 34 g of DHA. To prepare a second solution, 5 g of lithium chloride is dissolved in 0.15 L of dimethylacetamide (DMAA). The obtained amide-salt solvent is cooled to T = 10 ° C and a mixture of DAPBI and AIPDI is added to it at a ratio of 11:89 in the amount of 1.41 g. After complete dissolution, 0.55 g of PFDA is added to the solution, then 1.91 is added. g WPC.

The solutions are mixed at room temperature and a spinning solution is obtained with a polymer concentration of 4.0 wt.% And a viscosity of 600 P. After filtration and evacuation, molding is carried out through a die 200 by a wet method. The resulting filaments are drawn with a spinneret hood - 20%, dried at a temperature of 120 ° C and heat treated at a temperature of 350 ° C. Data on the properties of the finished yarn are shown in table 2.

Example 3. 90 g of lithium chloride is dissolved in 2.7 l of dimethylacetamide (DMAA). The obtained amide-salt solvent is cooled to T = 10 ° C and a mixture of DAPBI and AIPDI is added to it at a ratio of 20:80 in the amount of 30.72 g. After complete dissolution, PFDA in the amount of 6.93 g is added, then 30 , 91 g of DHA. To prepare a second solution, 10 g of lithium chloride is dissolved in 0.3 l of dimethylacetamide (DMAA). The obtained amide-salt solvent is cooled to T = 10 ° C and a mixture of DAPBI and AIPDI is added to it at a ratio of 20:80 in the amount of 3.41 g. After complete dissolution, PFDA in the amount of 0.37 g is added, then 1 93 g of duodenum.

The solutions are mixed at room temperature and a spinning solution is obtained with a polymer concentration of 3.7 wt.% And a viscosity of 404 P. After filtering and evacuating, molding is carried out through a die 200 by a wet method. The resulting yarn is drawn with a spun-drafted hood of -20%, dried at a temperature of 120 ° C and heat treated at a temperature of 350 ° C. Data on the properties of the finished yarn are shown in table 2.

Example 4. 85 g of lithium chloride are dissolved in 2.55 L of dimethylacetamide (DMAA). The obtained amide-salt solvent is cooled to T = 10 ° C and a mixture of DAFBI and AIPDI is added to it at a ratio of 25:75 in the amount of 32.30 g. After complete dissolution, 29.21 g of DCA are added to the solution.

To prepare a second solution, 15 g of lithium chloride are dissolved in 0.45 L of dimethylacetamide (DMAA). The obtained amide-salt solvent is cooled to T = 10 ° C and a mixture of DAFBI and AIPDI is added to it at a ratio of 25:75 in the amount of 5.7 g. After complete dissolution, 6.0 g of WPC is added to the solution. The solutions are mixed at room temperature and a solution is obtained with a polymer concentration of 3.5 wt.% And a viscosity of 300 P. After filtering, the film is formed by the dry-wet method. The resulting films are drawn with a hood of -30%, dried at a temperature of 120 ° C and heat treated at a temperature of 350 ° C. Data on the properties of the film are shown in table 2.

table 2 The ratio of monomer components for polycondensation and the properties of the obtained filaments and films Example No. Mixture composition Elongation at break,% The specific strength of the thread, SN / Tex diamines acid dianhydrides PFDA, pier. share DAFFBY, wt.% AIFDI, wt.% DOS, they say. share KDP, pier. share one 0 55 45 0.94 0.06 3.95 295 2 0.3 fifteen 85 0.95 0.05 4.1 305 3 0.2 twenty 80 0.9 0.1 4.5 281 4 (film) 0 25 75 0.8 0.2 3.8 150 cN / mm ²

Example 5. From the obtained multifilament yarn with a linear density of 29 tex with an elementary fiber diameter of 14.3 μm on STB-180 looms, a fabric is made by weaving 2/2 twill with a base density and a weft of 212 threads per 10 cm and a surface density of 198 g / m ² .

The fabric indicators presented in table 3 indicate that the fabric has high strength, ballistic, fire retardant properties.

Table 3 Fabric indicators No. Indicator Value one Breaking load of a strip of fabric 50 × 200 mm, N
- based
- by duck 5826
6166 2 Elongation at break,%
- based
- by duck 6.0
4,54 3 Tearing load of a strip of fabric measuring 70x200 mm, N - based > 100 - by duck 85.3 four Abrasion resistance, cycles - for cloth > 30000 - for abrasive 1300 5 Ballistic resistance of the package V ₅₀ , m / s -18 layers of fabric 537 - 30 layers of fabric 606 6 Fire resistance (flame holding time 30 s) Off, does not smolder after removal from flame

Claims (2)

1. A method for producing molded articles in the form of fibers, threads, films from heterocyclic aromatic polyamidoimides containing benzimidazole moieties, comprising preparing a first solution by dissolving a mixture of 5 (6) amino-2 (para-aminophenyl) benzimidazole with 5 (6) amino 2 (para-iminoquinone) benzodiimide in a weight ratio of (55:45) - (10:90) in dimethylacetamide cooled to 10 ° C, containing up to 4 wt.% Lithium chloride, first adding 0-0.3 mol. the proportion of paraphenylenediamine with respect to the specified mixture, and then the equimolar amount of terephthalic acid dichloride, preparing a second solution by dissolving a mixture of 5 (6) amino-2 (para-aminophenyl) benzimidazole with 5 (6) amino-2 (para-iminoquinone) benzidiimide in a mass ratio of (55:45) - (10:90) in dimethylacetamide cooled to 10 ° C, containing up to 4 wt.% lithium chloride, adding an equimolar amount of pyromellitic dianhydride, mixing 90-95 volume fractions of the first solution with 5- 10 volume fractions of the second solution at rooms temperature until the formation of a spinning solution with a dynamic viscosity of 300-600 P and a concentration of 3.5-4.0 wt.%, filtering the resulting spinning solution, evacuation, molding in a water-salt or water-alcohol precipitation bath, drying at a temperature not higher 120 ° C and heat treatment in a free state at a temperature not exceeding 350 ° C. 2. Technical fire retardant ballistic fabric made of threads and / or yarn of heterocyclic aromatic polyamidoimides containing benzimidazole fragments obtained by the method according to claim 1.