SU787424A1 - Method of preparing polyhexamethyleneterephththalamide - Google Patents

Description

cation, exceeds the amount of polymers in weight by ten times. Organic solvents, such as acetone, methanol, are toxic, flammable and explosive liquids (flammable liquids) that require special precautions when handling them.

The closest in technical essence to the present invention is a method for producing polyhexamethylene terephthalamide by solid-phase polycondensation of a precursor of polyhexamethylene terephthalamide obtained from hexamoventerephthalate (salt of TG). At the same time, TG salt is obtained in water (25-100% of water. From the weight of salt) in the form of solid particles at 15О-2ОО С under a pressure of 21-70 kg / mm of water vapor, which is due to the release of water during polycondensation, as well as loadable with salt. The second stage is dopopondensation of the precursor of polyhexamethylentereftLamide in a stream of inert gas at a temperature of 2 ° C below the melting point of the prepolymer. Logarichesky viscosity of the target product 1, S - -v. - - - .- 1.4, filterability index not lower than 0.1 2 The disadvantages of the method are the low molecular mass characteristics of the polyamide (logarithmic viscosity not higher than 1.11-1.14); An increase in molecular weight (1 p - 1.5-1.73) leads to the formation of a partially insoluble polymer in sulfuric acid, which results in two additional operations in the preparation of spinning solutions: filtering and determining the filterability index of each batch of polyhexamethylene terephthalamide. An inventive aspect is the preparation of a high molecular weight, completely soluble in sulfuric acid fiber-forming polymer,. The goal is achieved by the fact that polycondensation of hexamethylene terephthalate (TG salt) is carried out at 3-10-3.2O C, in the presence of 0.03-0.07 wt.% Synergistic thermostabilizing mixture of potassium iodide and Cu-containing macrocyclic compound of the formula in the following ratio components (Synergistic mixture, wt.%:

Potassium iodide 16,6-75

C-containing macrocyclic compound 25-83, 4 The polycondensation process is carried out at a high temperature, 40-50 seconds below the melting point of the polymer, and polyamides are obtained by logarithmic viscosity 2.19-2.56. The resulting polyamide is completely soluble in sulfuric acid without the formation of insoluble particles and helices. By dissolving polyamide in sulfuric acid at 96% concentration, it is possible to obtain viscous, transparent solutions containing 10-11% polymer. In a sulfuric acid hardened oleum (concentration 99-99.5%), clear solutions are obtained without gels containing 15-25% polyamide. Carrying out the polycondensation process at a temperature 20-30 s below the melting point of the polyamide precursor, i.e. at 260–290 ° C, even with the addition of thermal stabilizers, it does not give the desired results (the logarithmic viscosity of the polyamide does not exceed 1.2–1.32). Only carrying out polycondensation at temperatures of 50 and below the melting point of a non-precursor polyamide, namely, a finished poly (36O-365 C) in the presence of a synergistic mixture results in a PA with logarithmic viscosity 2-2.56. A positive effect has a mixture of only the specified composition. Each component, as well as a mixture of a different composition are ineffective,. The preparation of the high molecular weight polyamide is carried out from the hexameti salt. lendiamine and terephthalic acid (hexamethyl terephthalate). Sap synthesized as follows. Freshly distilled hexamethyandiamine, TPD 42 C, 196 C, is dissolved in 5 times the amount of distilled water in an atmosphere of inert rfl3ia (nitrogen, argon) at 60-65 C. Then an equimolar amount of tereftylic acid is metered and mixed until the mixture disappears. acid and the formation of a solution of the salt TG. Temperature 60-65 C, mixing in an inert gas atmosphere. A clear solution of salt. TG is filtered and cooled. When cooled, large white crystals of TG salt fall out. Salt TG is filtered off, washed with isoproyl alcohol and dried in air, and then with a vacuum-stacking cabinet at (Height mm). 57 Salt TG is recrystallized twice and used for polycondensation. The method for producing high molecular weight polyamide from TG salt is as follows. Salt TG with the addition of a mixture of potassium iodide and the C-containing compound (biline), carefully ground in a mortar, or subjected to policondensation in an autoclave, slowly raising the temperature for 2–410 C and continuously rotating the apparatus, or quickly melted the mixture at an ampoule under pressure. The resulting low molecular weight prepopimer with a relative viscosity of a 0.5% solution in concentrated sulfuric acid (96%) O, 081, 25, is then further heated at a temperature of 4 ° C for 3-5 hours at a temperature below the melting point of the polymer (320 ° C ) to form a high molecular weight sulfuric acid fully polyamide capable of forming spin solutions of high concentration. The relative viscosity of polyamine is 3.0 and 3.6, the logarithmic is 2.19 and 2.56, respectively. Example 1.2 g of salt, prepared on the basis of an equimolar ratio of hexamethylenediamine and terephthalic acid, is shifted from 0.001 g of stable and 0.0004 g of potassium iodide. The mixture is placed in an ampoule of heat-resistant stack PA. Argon is injected into the ampoule for 15 minutes and then sealed and placed on Yoomi. in the heated to the alloy By yes .. After 10 minutes, the contents of the ampoule are a homogeneous transparent melt, which is cooled in air. The resulting monolithic prepolymer block with 1.25 relative viscosity in sulfuric acid is removed from the ampoule and crushed. The low molecular weight polyamide is additionally heated at 32 ° C for 2 hours under argon atmosphere. The polymer is obtained from 11, 2-3.6 (2.32-2.56 and defined by the formula 2.MV where, the specific visibility). M.p. poly. amide .360-365 C. Polyamide is completely soluble in 96% sulfuric acid with the formation of solutions of 10% concentration, transparent and viscous, without gels and other insoluble particles: in 99% sulfuric acid they form 15-2O% -ftbie solutions of this polyamide, which can be used to produce durable filaments for wet and dry-wet molding. Example2. The south of the TG salt is thoroughly mixed with 0.005 g of stabilized and 0.002 g of potassium iodide and loaded into ampoules. The ampoule is rinsed with argon, sealed and placed in a 500 ml D autoclave with 4 O ml of water dp creating a back pressure during the formatic polycondensation process. The autoclave is heated to 31 for 1 h and then cooled. A low molecular weight prepolymer with a relative viscosity of 1.2 is ground, and then heated at 320 ° C. for 3 hours under argon. A polymer is obtained with a relative viscosity of 3, O (19), which is completely soluble in sulfuric acid without the formation of gels and insoluble particles. Example 3. A mixture of 20 g of TG salt, 0.02 g of potassium iodide, 0.01 g is stable, 80 ml of water is loaded into a 250 ml autoclave, rinsed with argon and for 1.5-2 hours the temperature is raised to ZOO C under pressure. Then, gradually over a period of 1 hour, the pressure is removed, the temperature is raised to 32 ° C and kept at this temperature for 5 hours in an argon atmosphere. A powdered product with a relative viscosity of 2.8 is obtained, which is completely soluble in sulfuric acid without gels. Polyamide is used for the preparation of spin solutions of 10-15% concentration. Example 4 (control). 5 g Salts of TG are loaded into an ampoule, washed with argon, sealed and placed in a block heated to 5-10 min. The molten prepolymer is then cooled (its logarithmic viscosity is 0.08), recovered and ground. Polycondensation is continued at 320 ° C. for 2 hours in an argon atmosphere. The resulting polyamide has an O viscosity of 8–0.85 and is completely insoluble in sulfuric acid. Example 5 (control). 1 g of TG salt is thoroughly mixed with 0, OOO2g of potassium iodide, loaded into an ampoule, into which argon is repeatedly passed, sealed. The process is then carried out as in Example 1. At the end of the polycondensation process, the polyamide is removed from the ampoule. Dark brown polymer, completely insoluble in sulfuric acid. After filtration, the soluble part has a logarithmic viscosity O, 82. 77 Example 6 (control). Example 5 is carried out, but instead of potassium iodide, 0,0005 g of stable is used. The resulting polymer is white, completely soluble in sulfuric acid, logarithmic viscosity 1.181, 22. Example 7; It was carried out as in Example 1, but the heat stabilizing Synergistic mixture consists of 0, OO08 g Cu-containing compound and O, 0002 g potassium iodide. Ratio, wt.%, 8O: 2O, respectively. The logarithmic viscosity of the polyamide obtained in 96% sulfuric acid is 1.38-1.4. Ponyamide. completely soluble in sulfuric acid 48 Example 8. It is carried out analogously to Example 1. A synergistic mixture consists of O, OOO8 g of a macrocyclic C-containing compound and 0, GO06 of a potassium yoaist. Logarithmic viscosity of polyhexamethylene terephthalamide 1.4. Example 9. It is carried out analogously to Example 1. A heat stabilizing mixture consists of 0, OOO2 g of C-containing macrocyclic compound and 0, OO04 g of potassium iodide. Logarithmic viscosity per meter 1.42-1.45. Similarly, the experiment was carried out at different ratios of the components of the synergistic mixture. In all experiments, the temperature of the stage X is 31 ° С, time 10 min, L stage 320 ° С, 2 h, argon. The data obtained are tabulated.

Without heat stabilizer O, O1 0.02 O, OZ

0.05

0.8-0.85

0.65

0.82

Claims (2)

PA does not dissolve, gels 9787 Thus, the use of the invention will make it possible to obtain a high molecular weight fiber-forming polyhexamethylene terephthalamide which is completely soluble in sulfuric acid, which will improve the quality of products based on it, in particular, tire cord. Claims The method of producing polyhexamethylene terephthalamide by polycondensation of hexamethylene terephthalate by heating, characterized in that, in order to obtain a high molecular weight, completely soluble in sulfuric acid fiber-forming polymer, the polycondensation is carried out at 310-320 ° C in the presence of 0.03, O7 wt.% Synergizing, thermostabilizing mixture of potassium iodide and Cu-co24 containing macrocyclic compounds of the formula in the following ratio of components of the synergistic mixture, wt.%: Potassium iodide 16.6-75 Cu-containing macrocyclic compound 25-83, 4 Sources of information taken into account during the examination 1. France Patent N 1.300.756, cl. From O8 gf, publish. 1962. 2. The patent of France No. 1.351.588, cl. C O8 §G, pubic. 1964 (prototype).