RU2476454C1 - Method of producing moulded articles in form of fibres and threads made from heterocyclic polyamides - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to the technology of producing moulded articles in form of fibres and threads made from a heterocyclic aromatic polyamide. Disclosed is a method of producing moulded articles from a heterocyclic aromatic polyamide, involving polycondensation of terephthaloyl chloride with a mixture of aminoimine 5(6)-amino-2(para-iminoquinone) benzamide, having melting point of 235±3°C, with aromatic diamine 5(6)-amino-2(para-aminophenyl) benzimidazole, having melting point of 216±3°C, with content of the latter of 5-60 wt % and para-phenylene diamine in amount of 0-30 wt %. The obtained polycondensation solution with dynamic viscosity of 300-800 P is homogenised, moulded into a settling aqueous-organic bath, washed, dried at temperature not higher than 120°C. The end products can be used to produce high-strength composite materials, articles operating under high loads, fabrics for making protective articles etc.

EFFECT: obtained articles have improved physical and mechanical properties (breaking tenacity, modulus of elasticity, breaking stress in microplastic) with low fluctuation of characteristics.

2 cl, 1 dwg, 5 tbl, 5 ex

Description

The invention relates to a technology for producing molded products in the form of fibers, threads from heterocyclic aromatic polyamides and can be used in the manufacture of composite materials, special products operating under high loads, fabrics for the manufacture of protective products against ballistic impacts, thermal shielding, rubber-technical and other products.

Known molded product in the form of fibers based on aromatic copolyamide (RF Patent No. 2167961), which is characterized by an elongation at break of at least 4.5% and a specific breaking load with a large variation interval (54-230) cN / tex. The copolymerization process is carried out in an amide-salt medium, and molding is carried out from sulfate solutions. This technology is complicated by additional solvent removal and recovery operations.

A known method of producing a molded product from heterocyclic aromatic copolyamides and copolyimides (RF Patent No. 2409710 from 01.20.2011) containing benzimidazole fragments, including the stages of synthesis, molding and heat strengthening of copolymers. As a result of copolycondensation of a mixture of aromatic diamines - diaminobenzimidazole, aminoiminobenzimidazole, p-phenylenediamine or without it with a mixture of aromatic dianhydrides - terephthaloyl chloride and pyromellitic dianhydride in dimethylacetamide with lithium chloride, no more benzenides containing benzenesides are obtained; or characterized in that in the aprotic solvent system of dimethylacetamide with lithium chloride (up to 4 wt.%) mixtures of diamines are introduced in stages: diam nobenzimidazole (DAFBI), aminoiminobenzimidazole (AIFBI) and paraphenylenediamine (PFDA) with or without it in a molar ratio of 0≤PFDA≤0.3. At the stage of obtaining the oligomeric system, terephthaloyl chloride (TFA) is added up to 95% of its molar fraction relative to the mixture of diamines, followed by the introduction of a mixture of the remaining amount (at least 5% molar parts) of terephthaloyl chloride with pyromellitic dianhydride in a ratio of 0.05≤PDA≤0.2 by mol (prototype )

However, the heterogeneity in the composition of the mixture of diamines (DAFBI) with (AIFBI) due to the lack of control of the composition of the mixture causes a large variation in the uncontrolled viscosity parameters of the spinning solutions and, as a result, an uncontrolled change in the physicomechanical properties of the finished product.

The absence of regulated melting points of aromatic diamines and their purity values (amount of impurities) does not allow programming the parameters of the formation of polycondensation solutions and the scope of the finished product.

The lack of regulated values of the compositions of the intermediate products before molding causes a high dispersion of physical and mechanical properties of the finished product.

An object of the invention is to provide high physical and mechanical properties (specific tensile load, elastic modulus, breaking stress in microplastics), achieve low fluctuation of indicators with a small interval of their change, and forecasting the areas of application of the finished product according to the properties of the intermediate products.

The technical problem is solved by the use of the starting aromatic amines 5 (6) -amino-2 (para-iminoquinone) benzodiimide (AI) with a melting point of 235 ± 3 ° C and 5 (6) -amino-2 (para-aminophenyl) benzimidazole (YES) with a melting point of 216 ± 3 ° C with a content of the latter of 5-60% and p-phenylenediamine (PFDA) in an amount of 0-30 wt.%, as well as the use of various quantitative compositions of the three starting aromatic amines in accordance with diagram 1 and the introduction of a control system technological parameters depending on the composition of the starting aromatic diamines and with properties of intermediate products with the provision of different technologies for the production of end products for various purposes, having a linear density of at least 29 tex, a specific breaking load of at least 80 cN / tex with a coefficient of variation of not more than 7.5%, elongation of at least 3.2 with a confidence interval not more than ± 0.4% and / or having a linear density of at least 29.4 tex with a coefficient of variation of not more than 5.0%, specific breaking load of at least 230 cN / tex with a coefficient of variation of not more than 5.0%, initial modulus elasticity of at least 14,900 kg / mm ^2, elongation of not less than 2.8%, breaking stress yarn tensile microplastics at least 480 kg / mm ^2.

The final products are used for the manufacture of high-strength composite materials, special products operating under high loads, fabrics for the manufacture of protective products against ballistic impacts, thermal protective, rubber products, etc.

The diagram is based on the principle of molar (weight) fractions of amines in the initial mixture (the working area is shaded).

The polycondensation solution, depending on the quantitative compositions of the starting aromatic amines, is characterized by a dynamic viscosity in the range of 300-800 P.

The structure of the obtained polyamide is characterized by the presence of benzimidazolamide (I), benzimidazolimide (II), benzodiimidquinoid (III), p-phenylenediamide (IV) groups (fragments I-IY).

The named groups were identified by the method of IR polarization spectroscopy according to the fluctuations of the characteristic bands (table A).

Table a Identification of copolymer fragments No. Fragment Number Type of communication IR polarization Frequency, cm ^-1 one. I C = o σ 1650 NH σ 3280-3300 2. II C = n π 1635 O-n π 3400-3450 3. C = o σ 1660 III C = C π 1642 C = c π 1642 C = n π 1635 four. C = O σ 1655 IV NH σ 3300

The polarization π and σ determines the location in space of the molecular group relative to the orientation axis of the polymer system.

The control and regulation system contains the following parameters: composition of the mixture and the melting point of aromatic amines (AI) and (YES), the quantitative composition of impurities in the mixture of aromatic amines (AI) and (YES), the moisture content and the amount of impurities in the solvent dimethylacetamide (DMAA), viscosity polycondensation product, the composition of the polycondensation products, the values of the plasticizing extract and heat treatment mode.

Determination of the composition (AI) and (YES) allows you to choose the field of application of the finished product.

Based on data on the composition of the mixture of amines and instrumental and chemical methods of analysis in the process of obtaining molded products in the form of fibers and threads, a plasticizing hood and a heat treatment mode are regulated.

The heat treatment mode includes drying at a temperature of no higher than 120 ° C or drying at a temperature of no higher than 120 ° C, followed by additional heat treatment of products at temperatures of 320-340 ° C and heat extraction at a temperature of 405 ° C or without it.

The method is material-saving, because allows you to get finished products with various properties without changing the composition of the input raw materials, and energy-saving due to the ability to control the parameters of the process of obtaining polymer systems and fiber formation by measuring the characteristics of the input and intermediate products.

The claimed formula is confirmed by examples.

Example 1. A method of obtaining a complex aramid yarn of linear density 29.4 tex for the manufacture of personal protective equipment.

For a mixture of amines (AI) :( YES), the composition of the mixture was 95: 5, the melting point of crystalline forms was 235.8 ° C and 219 ° C, and the impurity content was 0.3%.

Based on the data obtained, the scope of the finished product is determined - for the manufacture of personal protective equipment. For dimethylacetamide, the moisture content was determined - 0.05%, the moisture content was regulated to a value of 0.025 by adding regenerated DMAA. The impurity content in DMAA was 0.050%.

Production method

8.69 g of lithium chloride (LiCl) is dissolved in 300 ml of dimethylacetamide (DMAA) until it is completely dissolved.

5.96 g of the mixture (AI) are added to the resulting solution: (YES) and 2.8 g of p-phenylenediamine until the diamines are completely dissolved. The solution was cooled to 15 ° C. After dissolution, with constant stirring, 8.20 g of terephthaloyl chloride is added.

In a polycondensation solution, the viscosity parameter was determined - 540 P. With a viscosity value above the regulated value, a solvent is added to the system. According to the value of viscosity, a plasticizing extract is selected - (+ 55%).

The finished solution is homogenized for 2 hours with constant stirring at a temperature of 20 ± 2 ° C, and then vacuum and filtered. Before molding, the parameter of the composition of the polycondensation product in the film was determined by the IR method — the content of amidebenzimidazole groups was 80%.

The value of the composition determines the heat treatment mode.

Molding is carried out through a 200 × 0.08 die in a precipitation bath consisting of 95% organic components and 5% water at T = 20 ° C at a speed of 16.4 m / min with a negative die drawing and plasticizing (+ 55%). Then the threads are passed through a wash bath, drying rollers at T = 120 ° C and heat treated at T = 340 ° C. The physical and mechanical properties of the finished molded product are determined, which are presented in table 1.

Table 1. No. Indicator Value one. Linear Density 28.9 2. The coefficient of variation in linear density,% 2.9 3. Specific breaking load, cN / tex 280 four. Coefficient of variation in specific breaking load,% 4.0 5. Elongation at break,% 3.3 6. Confidence interval for elongation,% ± 0.4

Example 2. A method of obtaining a complex aramid yarn of linear density 29.4 tex for the manufacture of heat-resistant and rubber products

For a mixture of amines (AI) :( YES), the composition of the mixture was 40:60, the melting point of crystalline forms was 235 ° C and 213 ° C, and the impurity content was 0.4%.

Based on the data obtained, the scope of the finished product is determined - for the manufacture of heat-resistant and rubber products.

For dimethylacetamide, the moisture content was determined - 0.05%, the moisture content was regulated to a value of 0.025 by adding regenerated DMAA. The impurity content in DMAA was 0.1%. DMAA is used after additional regeneration with an impurity content of 0.05%.

Production method

8.69 g of lithium chloride (LiCl) is dissolved in 300 ml of dimethylacetamide (DMAA) until it is completely dissolved.

To the resulting solution was added 5.75 g of the mixture (AI) :( YES) and 1.44 g of p-phenylenediamine until the diamines were completely dissolved. The solution was cooled to 15 ° C. After dissolution, with constant stirring, 7.92 g of terephthaloyl chloride is added.

In a polycondensation solution, a viscosity parameter of 450 P was determined. A plasticizing extract (+ 50%) was selected for the viscosity value.

The finished solution is homogenized for 2 hours with constant stirring at a temperature of 20 ± 2 ° C, and then vacuum and filtered. Before molding, the parameter of the composition of the polycondensation product in the film was determined by the IR method — the content of amidebenzimidazole groups was 70%.

The value of the composition determines the heat treatment mode.

Molding is carried out through a 200 × 0.08 die in a precipitation bath consisting of 95% organic components and 5% water at T = 20 ° C at a speed of 16.4 m / min with a negative die drawing and plasticizing (+ 50%). Then the threads are passed through a wash bath, drying rollers at T = 120 ° C.

The physicomechanical properties of the finished molded product are determined, which are presented in table 2.

Table 2. No. Indicator Value one. Linear Density 28.8 2. The coefficient of variation in linear density,% 2.9 3. Specific breaking load, cN / tex 85 four. Coefficient of variation in specific 4.0 breaking load,% 5. Elongation at break,% 3.2 6. Confidence interval for elongation,% ± 0.4

Example 3. A method of obtaining a complex aramid yarn of linear density 58.8 tex for the manufacture of organoplastics.

For a mixture of amines (AI): (YES), the composition of the mixture was 82:18, the melting point of crystalline forms was 238 ° C and 219 ° C, and the impurity content was 0.5%.

Based on the data obtained, the scope of the finished product is determined - for the manufacture of organoplastics.

For dimethylacetamide, the moisture content was determined - 0.05%, the moisture content was regulated to a value of 0.03 by adding regenerated DMAA. The impurity content in DMAA was 0.03%.

Production method

8.69 g of lithium chloride (LiCl) is dissolved in 300 ml of dimethylacetamide (DMAA) until it is completely dissolved.

5.98 g of the mixture (AI) are added to the resulting solution: (YES) and 1.49 g of p-phenylenediamine until the diamines are completely dissolved. The solution was cooled to 15 ° C. After dissolution, with constant stirring, 8.22 g of terephthaloyl chloride is added.

In a polycondensation solution, a viscosity parameter of 780 Pz was determined. If the viscosity is higher than regulated, a solvent is added to the system. According to the value of viscosity, a plasticizing extract is selected - (+ 45%)

The finished solution is homogenized for 2 hours with constant stirring at a temperature of 20 ± 2 ° C, and then vacuum and filtered. Before molding, the parameter of the composition of the polycondensation product in the film was determined by the IR method — the content of amidebenzimidazole groups was 61%.

The value of the composition determines the heat treatment mode. Molding is carried out through a 300 × 0.08 spinneret into a precipitation bath consisting of 95% organic components and 5% water at T = 20 ° C at a speed of 12.5 m / min with a negative spinneret and plasticizing (+ 45%). Then the filaments are passed through a washing bath, drying rollers at T = 120 ° C and heat treated at T = 320 ° C, and then further pulled at 405 ° C.

The physicomechanical properties of the finished molded product are determined, which are presented in table 3.

Table 3. No. Indicator Value one. Linear Density 59.1 2. The coefficient of variation in linear density,% 2.9 3. Specific breaking load, cN / tex 250 four. Coefficient of variation in specific breaking load,% 2.3 5. Elongation at break,% 2,8 6. Confidence interval for elongation,% ± 0.2 7. The breaking stress of the thread under tension in microplastics, kgf / mm ² 520 8. Modulus of elasticity (GPa) / kgf / mm ² 150/15300

Example 4. A method of obtaining a complex aramid yarn of linear density 58.8 tex for the manufacture of special items.

For a mixture of amines (AI): (YES), the composition of the mixture was 90:10, the melting point of crystalline forms was 238 ° C and 217 ° C, and the impurity content was 0.55%.

Based on the data obtained, the scope of the finished product is determined - for the manufacture of special products.

For dimethylacetamide, the moisture content was determined - 0.04%, the moisture content was regulated to a value of 0.03 by adding regenerated DMAA. The impurity content in DMAA was 0.03%.

Production method

8.69 g of lithium chloride (LiCl) is dissolved in 300 ml of dimethylacetamide (DMAA) until it is completely dissolved.

To the resulting solution was added 8.03 g of a mixture of aromatic amines (AI) and (YES) until they were completely dissolved. The solution was cooled to 15 ° C. After dissolution, with constant stirring, 8.22 g of terephthaloyl chloride is added.

In a polycondensation solution, the viscosity parameter is determined - 380 P. At a viscosity value above the regulated value, a solvent is added to the system. According to the value of viscosity, a plasticizing extract is selected - (+ 60%).

The finished solution is homogenized for 2 hours with constant stirring at a temperature of 20 ± 2 ° C, and then vacuum and filtered. Before molding, the parameter of the composition of the polycondensation product in the film was determined by the IR method — the content of amide benzimidazole groups was 95%.

The value of the composition determines the heat treatment mode.

Molding is carried out through a 300 × 0.08 spinneret into a precipitation bath consisting of 95% organic components and 5% water at T = 20 ° C at a speed of 12.5 m / min with a negative spinneret and plasticizing (+ 60%). Then the threads are passed through a wash bath, drying rollers at T = 120 ° C and heat treated at T = 320 ° C.

The physicomechanical properties of the finished molded product are determined, which are presented in table 4.

Table 4. No. Indicator Value one. Linear density tex 59.0 2. The coefficient of variation in linear density,% 5.0 3. Specific breaking load, cN / tex 270 four. Coefficient of variation in specific breaking load,% 3.42 5. Elongation at break,% 4.5 6. Confidence interval for elongation,% ± 0.2

Example 5. A method of obtaining a complex aramid yarn of linear density 29.4 tex for the manufacture of composites.

For a mixture of amines (AI) :( YES), the composition of the mixture was 50:50, the melting point of crystalline forms was 238 ° C and 218 ° C, and the impurity content was 1.0%.

Based on the data obtained, the scope of the finished product is determined - for the manufacture of composites.

For dimethylacetamide, the moisture content was determined - 0.04%, the moisture content was regulated to a value of 0.05 by adding regenerated DMAA. The impurity content in DMAA was 0.05%. Additional regeneration of DMAA to an impurity content of 0.03%.

Production method

8.69 g of lithium chloride (LiCl) is dissolved in 300 ml of dimethylacetamide (DMAA) until it is completely dissolved.

8.03 g of a mixture of aromatic amines (AI) and (YES) are added to the resulting solution until they are completely dissolved. The solution was cooled to 15 ° C. After dissolution, with constant stirring, 8.22 g of terephthaloyl chloride is added.

In a polycondensation solution, the viscosity parameter is determined - 350 P. At a viscosity above the regulated value, a solvent is added to the system. According to the value of viscosity, a plasticizing extract is selected - (+ 75%).

The finished solution is homogenized for 2 hours with constant stirring at a temperature of 20 ± 2 ° C, and then vacuum and filtered. Before molding, the parameter of the composition of the polycondensation product in the film was determined by the IR method — the content of amidebenzimidazole groups was 100%.

The value of the composition determines the heat treatment mode.

Molding is carried out through a 200 × 0.08 die in a precipitation bath consisting of 95% organic components and 5% water at T = 20 ° C at a speed of 12.5 m / min with a negative die drawing and plasticizing (+ 75%). Then the threads are passed through a wash bath, drying rollers at T = 120 ° C.

The physicomechanical properties of the finished molded product are determined, which are presented in table 5.

Table 5. No. Indicator Value one. Linear density tex 29.0 2. The coefficient of variation in linear density,% 3.0 3. Specific breaking load, cN / tex 80 four. Coefficient of variation in specific breaking load,% 7.5 5. Elongation at break,% 4.5 6. Confidence interval for elongation,% ± 0.3

Claims (2)

1. A method for producing molded articles in the form of fibers, threads from a heterocyclic aromatic polyamide characterized by the presence of benzimidazolamide, benzimidazolimide, benzodiimidinoid groups in combination with or without p-phenylenediamide units, including polycondensation of terephthaloyl chloride (mixture of 6-aminoimino-6-aminoimino) paiminoquinone) benzdiimide having a melting point (235 ± 3) ° C, with aromatic diamine 5 (6) amino-2 (paraaminophenyl) benzimidazole having a melting point (216 ± 3) ° C, with a content the latter 5-60 wt.% and para-phenylenediamine in an amount of 0-30 wt.%, the resulting polycondensation solution with a dynamic viscosity of 300-800 P is homogenized, formed into a precipitating water-organic bath, washed, dried at a temperature not exceeding 120 ° C . 2. The method according to claim 1, characterized by additional heat treatment of products at temperatures of 320-340 ° C and heat extraction at a temperature of 405 ° C or without it.

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