KR970007489B1 - Aromatic polyamide and the manufacturing method thereof - Google Patents

Abstract

Aromatic polyamide(I) polymer having a high hardness and elastic properties is manufactured. In formula, R is aromatic ring, X is H, Cl, Br, I, NO2, CN, or C1-C4 alkyl or alkoxy, n is 10-10,000, Y is CONH(orNHCO), R' is phenyl, naphthalene, biphenyl, aromatic nucleus can substitute with H, Cl, Br, I, NO2, CN or C1-C4 alkyl or alkoxy. The degree of polymerization does not lower in the process and administration of factory is very easy because of without containing sulfuric acid in optical anisotropy aromatic polyamide.

Description

Optically anisotropic aromatic polyamide dope, moldings and preparation method thereof

1 is a phase variation of a polymer according to the concentration of an inorganic salt and a polymer in a polar solvent,

2 is a phase variation of a polymer according to the degree of polymerization of the polymer and the concentration in the polar solvent of the polymer,

3 is a phase variation of a polymer depending on the concentration of the polymer and the viscosity of the polymer dope.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to aromatic polyamides, and in particular, novel aromatic polyamide polymers and methods for preparing the same, optically anisotropic aromatic polyamide dope and preparation thereof which can be easily dissolved in polar organic solvents to form optically anisotropic dope. And a highly elastic aromatic polyamide fiber molding made from the above optically anisotropic aromatic polyamide dope.

In general, the wholly aromatic polyamide fiber and its molded products have high strength, high elasticity, heat resistance, abrasion resistance, and electrical insulation, and are useful for special industrial fields such as composite materials and building materials such as aircraft, automobile industry, leisure, and sporting goods. Is being used. Due to such usefulness, various manufacturing methods for the wholly aromatic polyamide fibers and their molded articles have been developed. In the case of optically anisotropic aromatic polyamide dope, the polymer chains are oriented in the fiber axis direction when they are extruded from the spinneret during molding. Since the high-strength high-elastic fibers can be produced without the post-stretching process, the research on the preparation of optically anisotropic aromatic polyamide dope is active.

For example, DuPont, USA, dissolves polybenzamide and polypanaphenylene terephthalamide in 100% sulfuric acid to produce optically anisotropic aromatic polyamide dope and extrusion spray to produce high strength, high elastic aromatic polyamide fibers. Methods have been developed and industrialized (see US Pat. Nos. 3,671,542 and 3,673,143).

In addition, U.S. Patent No. 4,018,735 discloses a method for preparing anisotropic aromatic dope by dissolving an aromatic polyamide prepared by introducing 5 to 35 mol% of a heterocyclic unit such as benzoxazole or imidazole in sulfuric acid. .

However, the methods disclosed in the above-mentioned documents are carried out by heating and dissolving aromatic polyamide in 100% sulfuric acid in preparing optically anisotropic dope of aromatic polyamide, thereby lowering the degree of polymerization during dissolution and deteriorating physical properties. It causes environmental pollution and difficult process control.

The present invention has been made to solve such problems of the prior art, and a first object of the present invention is to provide a novel aromatic polyamide polymer capable of forming optically anisotropic aromatic polyamide dope under milder conditions than before. Has

The present invention also has a second object to provide an optically anisotropic aromatic polyamide dope comprising the aromatic polyamide polymer described above and free of sulfuric acid and a method for producing the same.

The present invention also has a third object to provide a high-strength, high-elasticity aromatic polyamide fiber mainly containing the novel aromatic polyamide described above and a method for producing the same.

In order to achieve the above first object, the present invention provides an aromatic polyamide polymer represented by the following structural formula (I).

[In Structural Formula (I)

Wherein X = H, Cl, Br, I, NO ₂ or an alkyl or alkoxy group having 1 to 4 carbon atoms, n represents an integer of 10 to 100,000, to be.]

The aromatic diamine forming the repeating unit of the above formula (I) is characterized by having a nitrile group in the aromatic nucleus.

The aromatic polyamide polymer of the structural formula (I) is obtained by condensation polymerization of an aromatic diamine substituted with a nitrile group in an aromatic nucleus with an aromatic dieside halide.

Aromatic diamines that can be used in the present invention are characterized by having an aromatic nuclei nitrile group and representative examples are as follows, and are not limited to these examples as shown in general structural formula (I).

Wherein Y is Cl, Br, I, NO ₂ or an alkyl or alkoxy group having 1 to 4 carbon atoms.

Representative examples of the aromatic dieside halides that can be used in the present invention include isophthalic acid chloride, naphthyl acid chloride, diphenyl acid chloride, which are unsubstituted or have Cl, Br, I, NO ₂ or 1 to 4 carbon atoms. It may have an alkyl or alkoxy group.

The aromatic polyamide polymer represented by the above structural formula (I) prepared according to the present invention is 2.0 or more, preferably 2 to 2, having an intrinsic viscosity soluble in a polar organic solvent containing an inorganic salt and substituted with a nitrile group in the aromatic nucleus. High molecular weight novel aromatic polyamide polymer of ten.

Intrinsic viscosities are obtained by extrapotation using a Ubbelohde viscometer with 5 viscosity lean concentrations (30 ° C., using 98% sulfuric acid).

(t: viscometer passage time of solution, t ₀ : viscometer passage time of solvent only, C: concentration of solution)

The aromatic polyamide of the present invention can be confirmed by the nitrile group absorption characteristic band appearing at 2230 cm ^-1 of the infrared spectra spectrum.

The aromatic polyamide polymer of the above formula (I) is capable of achieving the second object by forming an optically anisotropic aromatic polyamide polymerization dope which exhibits a silvery-white gloss while the polymerization solution is stirred when polymerized by the following method. have.

1) preparing a polymerization solvent comprising an amide organic solvent, a urea organic solvent, or a mixed organic solvent thereof;

2) adding and dissolving an aromatic diamine substituted with a nitrile group to the aromatic core in the polymerization solvent,

3) pyridine is added to the solution as a polycondensation catalyst,

4) Add the aromatic dieside halide while maintaining the temperature of the solution at 0-50 [deg.] C. with vigorous stirring,

5) Stirring is continued for 1 to 360 minutes to obtain a highly viscous polymer solution having a silvery white color during stirring.

The highly viscous polymer solution is an optically anisotropic polyamide dope which appears in various colors when viewed under a polarization microscope. The polymer solution is spun into a coagulation bath through a spinneret and easily processed into a high-strength, high-elastic polyamide fiber, film, or pulp molding. Can be. In addition, the optically anisotropic polyamide dope system according to the present invention does not contain sulfuric acid, so there is no deterioration in polymerization degree of the polyamide polymer, and there are various advantages in that it can be easily managed in the process.

In the present invention, as the organic solvent, any organic solvent of amide or urea can be used, but especially N-methyl-2-pyrrolidone (NMP), N, N-dimethylacetamide (DMAc) hexa The use of methylphosphoamide (HMPA), N, N, N ', N'-tetramethyl urea (TMU), N, N-dimethylformamide (DMF), dimethylsulfoxide (DMSO) or mixtures thereof desirable.

In addition, an inorganic salt may be further added to the polymerization solvent used in the present invention in order to increase the solubility of the aromatic polyamide. Representative examples of such inorganic salts include halogenated alkali metal salts or halogenated alkaline earth metal salts such as CaCl ₂ , LiC ₁ , NaCl, KCl, LiBr, KBr, and the like.

These inorganic salts may be added alone or in the form of a mixture of two or more kinds. The amount of the inorganic salt added is preferably in the range of 12% by weight or less relative to the total amount of the polymerization solvent. When the amount of the inorganic salt added exceeds 12% by weight, the objective effect of the present invention can no longer be expected and becomes uneconomical.

The second object of the present invention is that in addition to the polymerization method described above, the aromatic polyamide of the structural formula (I) is 7 wt% or more in a polar organic solvent containing at least 1 wt% or more of an inorganic salt. It may also be achieved by a method of dissolving at 20 ° C., preferably 20 ° C. to 70 ° C., to obtain a silvery white optically anisotropic dope.

As the polar organic solvent, any organic solvent of amide or urea can be used, but in particular, N-methyl-2-pyrrolidone (NMP), N, N-dimethylacetamide (DMAc) hexamethylphosphoamide ( Preference is given to using HMPA), N, N, N ', N'-tetramethylurea (TMU), N, N-dimethylformamide (DMF), dimethylsulfoxide (DMS) or mixtures thereof.

In addition, representative examples of the inorganic salts used in the present invention include halogenated alkali metal salts or halogenated alkaline earth metal salts such as CaCl ₂ , LiC ₁ , NaCl, KCl, LiBr, KBr, and the like.

These inorganic salts may be added alone or in the form of a mixture of two or more kinds. The addition amount of an inorganic salt is made to contain at least 1 weight% or more in an organic polar solvent. Preferably 1-10 weight% is good. When the content of the inorganic salt is 1% by weight or less, the solubility of the polyamide polymer of the present invention represented by the above structural formula (I) to the organic polar solvent is poor, making it difficult to prepare an optically anisotropic dope, and the content of the inorganic salt is 10% by weight or more. As the inorganic salt content increases, there is no effect of improving the solubility of the polyamide polymer, which is economically undesirable. In the present invention, the concentration of the polyamide polymer in the organic polar solvent for forming the optically anisotropic dope may vary depending on the degree of polymerization of the polyamide polymer, the viscosity of the dope or the concentration of the inorganic salt in the organic polar solvent, but at least 7% or more. It is preferably 7 to 23% by weight. At 7% or less, the polymer content is low, so that the optical properties of the dope are isotropic. At 23% by weight or more, the optical properties of the dope are present in a solid state, thereby preventing the effect of the present invention (FIG. 1).

In addition, in preparing the optically anisotropic polyamide dope of the present invention, it is preferable that the physical properties of the polyamide polymer represented by the above-mentioned structural formula (I) have a degree of polymerization of at least two or more intrinsic viscosity.

When the degree of polymerization of the polyamide polymer is 2 or less, the optically anisotropic dope desired in the present invention cannot be obtained even if the concentration of the polyamide polymer in the organic polar solvent is increased (FIG. 2).

In addition, the viscosity of the dope, together with the polymer content in the dope, has a great influence on the optical properties of the dope.

Optically anisotropic dope is obtained when the viscosity of the dope is 1000 poise or more and the polymer content in the dope is in the range of 10 to 20% by weight (see FIG. 3).

FIG. 1 shows an isotropic and anisotropic phase diagram depending on the concentration of the polymer and the concentration of DMAc-LiCl when the aromatic polyamide polymer of formula (I) of the present invention is dissolved in a DMAc-LiCl solution.

As shown in FIG. 1, when the content of the inorganic salt LiCl in the polar organic solvent dimethylacetamide is 1% or less, the solubility of the polyamide polymer is decreased so that the optical properties of the dope are isotropic or exist in the solid state in the solvent. Done. The optical properties of the dope show anisotropy within the concentration of 7-23% by weight of the polymer in the polar organic solvent.

FIG. 2 shows isotropic and anisotropic phase shifts depending on the extreme viscosity of the degree of polymerization of the aromatic polyamide of the formula (I) of the present invention and the concentration of the polymer. The LiCl concentration in DMAc is 4% by weight.

As shown in FIG. 2, even when the concentration of the polymer in the polar organic solvent is 7% or more, which shows optical anisotropy in FIG. 1, the degree of polymerization of the polymer does not exhibit anisotropy when the polymer viscosity is 2 or less.

3 shows the concentration of the aromatic polyamide polymer of formula (I) (wherein the LiCl concentration in DMAc is 4% by weight) and the viscosity of the dope, showing anisotropy at a specific concentration (10-20% by weight). It is shown to be much lower than the viscosity showing isotropy.

The present invention provides a molded article of a fiber, pulp or film obtained by spinning and solidifying an optically anisotropic spinning dope of polyamide represented by the following structural formula (I) in order to achieve the third object.

[In Structural Formula (I)

Wherein X = H, Cl, Br, I, NO ₂ or an alkyl or alkoxy group having 1 to 4 carbon atoms, n represents an integer of 10 to 100,000, to be.]

The aromatic polyamide fiber represented by the above structural formula (I) has a tensile strength of 10 g / d or more and a tensile modulus of 450 g / d or more and has high strength and high elasticity.

The aromatic polyamide fiber of the present invention represented by the above structural formula (I) comprises an aromatic diamine and an aromatic dieside halide monomer substituted with a nitrile group in an aromatic nucleus comprising an amide solvent, a urea solvent, or a mixed solvent thereof. The aromatic represented by the above structural formula (I) obtained by polycondensation reaction at a polymerization temperature of 0 to 50 ° C. using pyridine as a polymerization catalyst in a polymerization solvent in which an inorganic salt of a halogenated alkali metal salt or an alkali alkaline earth metal salt is added to a polar organic solvent. Optically anisotropic polyamide dope comprising a polyamide polymer; Or dissolving the aromatic polyamide of the above formula (I) in an organic solvent containing an inorganic salt of an alkali metal salt or a halogenated alkaline earth metal salt to prepare an optically anisotropic aromatic polyamide dope; It is produced by spinning and coagulating by washing and drying with a coagulation bath with an air layer of 2-5 cm through the spinneret.

Next, the present invention will be described in more detail with reference to preferred embodiments of the present invention. However, these examples are provided to more easily understand the present invention, but the present invention is not limited to the following embodiments.

Example 1

87 ml of dimethylacetamide (DMAc) was taken in a 250 ml reactor under nitrogen stream, and 3 g of LiCl was added thereto to completely dissolve the polymerization solvent. Here, 12 g of 4,4'-diamino-2-cyano benzanilide was added and completely dissolved. 12.6 ml of pyridine was added and 9.66 g of terephthaloyl chloride was added at once with vigorous stirring while maintaining the temperature of the solution at 10-15 ° C. Immediately after the addition, the polymerization solution increased in viscosity to give a silvery white optically anisotropic dope having viscosity after a few minutes. Anisotropic dope was confirmed by the polarizing microscope. The ultimate viscosity (measured in 30 ° C., 98% sulfuric acid solution) of the recovered aromatic polyamide was 4.7.

The anisotropic dope is extruded and sprayed through a spinneret into an air layer of 1 to 2 cm and solidified in a 20% aqueous dimethylacetamide solution maintained at about 5 ° C. and wound on a roller at the maximum speed. After sufficiently washing with distilled water, the tensile strength of the dried filament in the dryer at 150 ℃ was 160g / d, tensile modulus was 450g / d.

Example 2

50 ml of dimethylacetamide (DMAc) was taken in a 250 ml reactor under a nitrogen stream, and 1.8 g of LiCl was added thereto to completely dissolve the polymerization solvent. To this was added 8.3 g of 4,4'-diamino-2-cyano benzanilide and completely dissolved. 8 ml of pyridine was added and 6.68 g of terephthaloyl chloride was added at once with vigorous stirring, maintaining the temperature of the solution at 10-15 ° C. Immediately after the addition, the polymerization solution increased in viscosity to give a silvery white optically anisotropic dope having viscosity after a few minutes. Anisotropic dope was confirmed by the polarizing microscope. The ultimate viscosity (measured in 30 ° C., 98% sulfuric acid solution) of the recovered aromatic polyamide was 4.5.

The anisotropic dope is extruded through a spinneret into an air layer of 1 to 2 cm and solidified in a 20% aqueous dimethylacetamide solution maintained at about 5 ° C. and wound on a roll at maximum speed. After washing sufficiently with distilled water, the tensile strength of the dried filament in a dryer at 150 ° C. was 18 g / d and the tensile modulus was 500 g / d.

Example 3

50 ml of dimethylacetamide (DMAc) was taken in a 250 ml reactor under a nitrogen stream, and 1.6 g of LiCl was added thereto to completely dissolve the polymerization solvent. 7.97 g of 4,4'-diamino-2-cyano benzanilide was added thereto and completely dissolved. 8.4 ml of pyridine was added and 6.42 g of terephthaloyl chloride was added at once with vigorous stirring while maintaining the temperature of the solution at 10-15 ° C. Immediately after the addition, the polymerization solution increased in viscosity to give a silvery white optically anisotropic dope having viscosity after a few minutes. Anisotropic dope was confirmed by the polarizing microscope. The ultimate viscosity (measured in 30 ° C., 98% sulfuric acid solution) of the recovered aromatic polyamide was 5.9.

The anisotropic dope is extruded and sprayed through a spinneret into an air layer of 1 to 2 cm and solidified in a 20% aqueous dimethylacetamide solution maintained at about 5 ° C. and wound on a roller at the maximum speed. After washing sufficiently with distilled water, the tensile strength of the dried filament in a dryer at 150 ° C. was 18 g / d and the tensile modulus was 400 g / d.

Example 4

50 ml of dimethylacetamide (DMAc) was taken in a 250 ml reactor under a nitrogen stream, and 1.7 g of LiCl was added thereto to completely dissolve the polymerization solvent. To this was added 4,4'-diamino-2-cyano benzanilide g and completely dissolved. 8.4 ml of pyridine was added and 6.43 g of perephthaloyl chloride was added at once with vigorous stirring, maintaining the temperature of the solution at 10-15 ° C. Immediately after the addition, the polymerization solution increased in viscosity to give a silvery white optically anisotropic dope having viscosity after a few minutes. Anisotropic dope was confirmed by the polarizing microscope. The ultimate viscosity (measured in 30 ° C., 98% sulfuric acid solution) of the recovered aromatic polyamide was 5.9.

The anisotropic dope is extruded and sprayed through a spinneret into an air layer of 1 to 2 cm and solidified in a 20% aqueous dimethylacetamide solution maintained at about 5 ° C. and wound on a roller at the maximum speed. After washing sufficiently with distilled water, the tensile strength of the dried filament in the dryer at 150 ° C. was 22 g / d and the tensile modulus was 500 g / d.

Example 5

130 ml of dimethylacetamide (DMAc) was taken in a 250 ml reactor under nitrogen stream, and 3.3 g of LiCl was added thereto to completely dissolve the polymerization solvent. Here 8 g of 4,4'-diamino-2-cyano benzanilide was added to dissolve completely. 8 ml of pyridine was added and 6.44 g of terephthaloyl chloride was added at once with vigorous stirring while maintaining the temperature of the solution at 10-15 ° C. Immediately after the addition, the polymerization solution increased in viscosity to give a silvery white optically anisotropic dope having viscosity after a few minutes. Anisotropic dope was confirmed by the polarizing microscope. The ultimate viscosity (measured at 30 ° C. and 98% sulfuric acid solution) of the recovered aromatic polyamide was 6.3.

10 g of the recovered aromatic polyamide was added to 52.5 g of a 4% by weight LiCl-dimethylacetamide solution to prepare a silver white anisotropic dope while dissolving at 50 ° C. The anisotropic dope is extruded through a spinneret into an air layer of 1-2 cm, solidified through a 20% aqueous dimethylacetamide solution maintained at about 5 ° C. and wound on a roller at maximum speed. After washing sufficiently with distilled water, the tensile strength of the dried filament in the dryer at 150 ° C. was 15 g / d and the tensile modulus was 450 g / d.

Claims (18)

An aromatic polyamide polymer represented by the following structural formula (I). [In Structural Formula (I) X represents H, Cl, Br, I, NO ₂ , CN or an alkyl or alkoxy group having 1 to 4 carbon atoms, n represents an integer of 10 to 100,000, and Y represents Indicates. And R 'represents a phenyl group, a naphthalene group and a biphenyl group, and these aromatic nuclei may be substituted with H, Cl, Br, I NO ₂ , CN or an alkyl or alkoxy group having 1 to 4 carbon atoms.] The aromatic polyamide polymer according to claim 1, wherein a nitrile group absorption characteristic band appears at 2230 cm ^-1 of the infrared spectral spectrum. The aromatic polyamide polymer according to claim 1, which is soluble in a polar organic solvent containing an inorganic salt. The aromatic polyamide polymer according to claim 1, which has a molecular weight having an intrinsic viscosity of 2 to 10. 1) preparing a polymerization solvent comprising an amide organic solvent, a urea organic solvent, or a mixed organic solvent thereof, 2) adding and dissolving an aromatic diamine substituted with a nitrile group in an aromatic core to the polymerization solvent, and 3) the solution. Pyridine was added as a polycondensation catalyst, 4) the aromatic dieside halide was added while maintaining the temperature of the solution at 0.-50 占 폚 and vigorously stirred, and 5) the polymerization reaction was continued for 1 to 360 minutes. A method for producing an optically anisotropic aromatic polyamide polymer dope represented by the above structural formula (I). The method of claim 5, wherein the organic solvent is N-methyl-2-pyrrolidone, N, N-dimethylacetamide, hexamethylphosphoamide, N, N, N ', N'-tetramethyl urea, N A method for producing an optically anisotropic aromatic polyamide polymerization dope represented by Structural Formula (I), characterized in that it is a polar organic solvent selected from the group consisting of N-dimethylformamide and dimethyl sulfoxide (DMSO). The optically anisotropic poly represented by formula (I) according to claim 5, wherein the inorganic salt is one or a mixture of two or more selected from the group consisting of CaCl ₂ , LiC ₁ , NaCl, KCl, LiBr, and KBr. Process for the preparation of amide polymerized dope. The method for producing an optically anisotropic polyamide polymerization dope according to any one of claims 5 to 7, wherein the amount of the inorganic salt added is 12% by weight or less based on the total amount of the polymerization solvent. . The method of claim 5, wherein the aromatic diamine is an aromatic diamine compound substituted with a nitrile group in an aromatic nucleus. The aromatic diamine according to claim 5 or 9, wherein a nitrile group is substituted for the aromatic nucleus. Wherein Y is Cl, Br, I, NO _2, or an alkyl or alkoxy group having 1 to 4 carbon atoms. Optically anisotropic polyamide polymerization dope represented by formula (I), characterized in that it is selected from the group consisting of: Manufacturing method. The method of claim 5, wherein the aromatic dieside halide is an isophthalic acid chloride, naphthyl acid chloride, diphenyl acid chloride, or a substituent of Cl, Br, I, NO ₂ or an alkyl or alkoxy group having 1 to 4 carbon atoms. A method for producing an optically anisotropic polyamide polymerized dope represented by Structural Formula (I), which is selected from the group consisting of: Optically anisotropic aromatic polyamide, characterized in that the aromatic polyamide polymer represented by the formula (I) is dissolved in a polar organic solvent containing at least 1% by weight or more of inorganic salts at a dissolution temperature of 20 to 100 ° C. Method for preparing dope. 13. The method for producing optically anisotropic aromatic polyamide dope according to claim 12, wherein the content of the dope of the aromatic polyamide polymer represented by the above formula (I) is 7 to 23% by weight. The method for producing an optically anisotropic aromatic polyamide dope according to claim 12 or 13, wherein the aromatic polyamide represented by Structural Formula (I) has an intrinsic viscosity of 2 to 10 minutes. 13. The method for preparing optically anisotropic aromatic polyamide dope according to claim 12, wherein the content of the inorganic salt is 1 to 10% with respect to the polar organic solvent. 16. The optically anisotropic aromatic polyamide dough according to claim 12 or 15, wherein the inorganic salt is selected from one or two or more selected from the group consisting of CaCl ₂ , LiC ₁ , NaCl, KCl, LiBr, and KBr. Method of preparation A molded article of the group consisting of fibers, pulp or film of the polyamide represented by the structural formula (I), which is obtained by spinning and solidifying the optically anisotropic spinning dope of the polyamide represented by the structural formula (I). 18. The molded article according to claim 17, wherein the polyamide fibers represented by the above formula (I) have high strength and high elastic properties of 10 g / d or more in tensile strength and 450 g / d in tensile modulus.