KR100375244B1 - Aromatic polyamide polymer, polymer dope, and method for producing the same - Google Patents

Abstract

PURPOSE: Provided are an aromatic polyamide polymer which shows increased solubility in polar organic solvents and forms an aromatic polyamide dope at milder condition than ever without decreasing of heat resistance and strength, a polymer dope, and a method for producing the same. CONSTITUTION: The polyamide polymer has a recurring unit of formula 1. The polyamide polymer is produced by reacting an aromatic diamine compound of formula 2 and an aromatic diacid compound of formula 3 in the presence of polymerization solvent selectively containing inorganic salt. In the formulas 1-3, R is , X is CN, Cl, Br, I, NO2, C1-C4 alkyl group or C1-C4 alkoxy group, n is an integer of 10-100,000, R' , and Y is halogen elements such as F, Cl, Br, I.

Description

Aromatic Polyamide Polymers, Polymerized Dopes, and Methods for Making the Same

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to aromatic polyamides, and in particular, to novel aromatic polyamide polymers, polymeric dope, and methods for their preparation that are readily soluble in polar organic solvents.

In general, the wholly aromatic polyamide fiber and its molded products are characterized by high strength, high elasticity, heat resistance, abrasion resistance, and electrical insulation, which are useful for special industrial fields such as composite materials and construction materials such as aircraft, automobile industry, leisure, and sporting goods. Is being used. However, aromatic polyamide resins are poorly soluble in common polar organic solvents. Therefore, when the aromatic polyamide resin is dissolved in a polar organic solvent for the production of moldings, it is difficult to prepare a high concentration of the polymerization dope due to the poor solubility in the solvent of the resin, resulting in a problem that the radioactivity and the moldability deteriorate. do.

In order to solve such a problem, a method of producing an aromatic polyamide polymerization dope using a high concentration of sulfuric acid as a solvent is generally used.

For example, US Pat. Nos. 3, 671, 542 and 4, 018, 735 disclose that optically anisotropic aromatic polyamide dope is prepared by heating and dissolving polybenzamide and polyparaphenylene terephthalamide in 100% sulfuric acid. It has been developed and industrialized to produce a high-strength highly elastic aromatic polyamide fiber by spraying.

In addition, US Patent Nos. 4, 018 and 735 disclose a method for preparing anisotropic aromatic dope by dissolving aromatic polyamide prepared by introducing 5 to 35 mol% of heterocyclic units such as benzoxazole or imidazole in sulfuric acid. Is disclosed.

However, the methods disclosed in the above-mentioned documents, in the preparation of optically anisotropic dope of aromatic polyamide, by dissolving the aromatic polyamide in 100% sulfuric acid by heating dissolution, the degree of polymerization is lowered during dissolution, and also the use of sulfuric acid It causes environmental pollution and difficult process control.

In order to improve the above problems due to the use of sulfuric acid, Japanese Unexamined Patent Publication Nos. 51-76386, 51-134743, 51-136916, 61-252229, 62-27431, 62-225530, 62-177002 and 62-177023 disclose methods for introducing ether bonds into aramid chains.

Such a method improves the solubility of the aromatic polyamide in the polar organic solvent, but causes a problem in that heat resistance and strength are lowered due to ether bonds introduced into the aromatic polyamide chain. This can be predicted by the result of ether bonding that the primary structure of the aramid chain has a zigzag shape.

US Patent No. 5006629 and 5274071 disclose a method of copolymerizing benzidine diamine containing a substituent as a diamine repeating unit, dicarbonyl repeating unit having a fused benzene ring, diamine having an ether bond, and the like. This method does not improve the solubility of the aromatic polyamide in the polar organic solvent.

The present invention relates to a novel aromatic polyamide to improve these problems of the prior art, so that the solubility in the polar organic solvent can be increased without reducing the heat resistance and strength to form an aromatic polyamide dope under milder conditions than before. To provide novel aromatic polyamide polymers. It is also an object to provide aromatic polyamide dope comprising the aromatic polyamide polymer described above and containing no sulfuric acid.

The present invention relates to novel aromatic polyamide polymers, polymeric dope and processes for their preparation that are readily soluble in polar organic solvents.

The aromatic polyamide polymer of the present invention has a repeating unit of the following structural formula (I), and the aromatic diamine compound of the following structural formula (II) and the aromatic dieside compound of the following structural formula (III) optionally contain an inorganic salt under a polymerization solvent. It is made by reaction.

In formulas (I) to (III), R is And R 'is X is CN, Cl, Br, I NO ₂ , an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms, n is an integer of 10-100,000, Y is F, Cl, Br, I and the like. Halogen element.

The aromatic polyamide polymerization dope of this invention consists of 5-30 weight% of aromatic polyamide polymers which have a repeating unit of following structural formula (I), and 70-95 weight% of polar organic solvents which optionally contain an inorganic salt.

In formulas (I) to (III), R is And R 'is A represents, X is an alkoxy group having 1 to 4 carbon atoms or an alkyl group of CN, Cl, Br, I, NO 2, 1 to 4 carbon atoms, n is an integer from 10-100000.

The method for producing the aromatic polyamide polymer and the polymerization dope of the present invention may be prepared by the following process.

(A) preparing a polymerization solvent consisting of an amide organic solvent, an urea organic solvent, or a mixed organic solvent thereof, optionally containing an inorganic salt,

(B) adding and dissolving the aromatic diamine compound of formula (II) to the polymerization solvent;

(C) maintaining the temperature of the solution at 0 to 50 DEG C and adding the aromatic dieside compound of the structural formula (III) with strong stirring;

(D) optionally selected from the group consisting of carbonates, hydrides, hydroxides and oxides of alkali or alkaline earth metals of LiCO ₃ , CaCO ₃ , LiH, CaH ₂ , LiOH, Ca (OH) ₂ , Li ₂ O or CaO; The addition of the inorganic alkali compound to the reaction system to neutralize the acid generated during the polymerization reaction to prepare a highly viscous polymer dope,

(E) Water is added to the polymer dope to precipitate the polymer, and then the polymer is recovered.

In the present invention, the organic solvent may be an amide solvent, a urea solvent or a mixed solvent thereof. Especially N-methyl-2-pyrrolidone (NMP), N, N-dimethylacetamide (DMAc), hexamethylphosphoamide (HMPA), N, N, N ', N'-tetramethylurea (TMU) Preference is given to using N, N-dimethylformamide (DMF), dimethylsulfoxide (DMSO) or mixtures thereof. In addition, the polymerization solvent used in the present invention optionally contains an inorganic salt in order to increase the solubility of the aromatic polyamide. Representative examples of such inorganic salts include halogenated alkali metal salts, halogenated alkaline earth metal salts such as CaCl ₂ , LiCl, NaCl, KCl, LiBr and KBr.

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 5% by weight or less based on the total amount of the polymerization solvent. That is, the weight of the inorganic salt is preferably 5% or less based on the total amount of the polymerization solvent to which the inorganic salt is added.

When the added amount of the inorganic salt exceeds 5% by weight, the effect of increasing the polymer solubility is insignificant compared to the added amount, which is uneconomical.

In this invention, 1, 4'-bis (4-aminophenyl carboxamido) benzene which has a substituent in benzene is used as a compound which has a repeating unit of structural formula (I). Substituted cyano group is the best to achieve the object of the present invention, but in addition to the cyano group, a substituted halide group, nitro group, alkyl having 1 to 4 carbon atoms or alkoxy group having 1 to 4 carbon atoms may be used. Terephthaloyl chloride was used as an aromatic dieside compound of the formula (III).

Aromatic dieside halides having dicarbonyl repeating units in the production of polyamide polymers react with aromatic diamines in a 1: 1 molar ratio, but in order to control the degree of polymerization of the resulting polymer, one component may be added in excess of the molar ratio. A monoacid halide or amine compound may be added to terminate the reaction. After the polymerization reaction, an inorganic alkali compound may be optionally added to neutralize the polymerization dope.

In order to maintain a constant degree of polymerization in the polymerization dope prepared in the present invention, the concentration of the polymerization dope is an important parameter. The concentration of the polymer in the polymerization dope is preferably 5 to 30% by weight. More preferably, the polymerization dope having uniform physical properties may be prepared when it is 10 to 20% by weight. At this time, the intrinsic viscosity has a range of 3 to 10.

At the time of superposition | polymerization, since reaction of the aromatic diamine compound of structural formula (II) and the aromatic dieside compound of structural formula (III) advances very quickly, it is preferable to maintain the temperature of a polymerization system in the range of 0-50 degreeC. It is also important to avoid contamination with water and other impurities that can terminate the polymerization.

The polymer in the high viscosity polymer solution thus prepared was found to have a very high solubility in the polymerization solvent, thereby forming a stable polymerization dope. When the polymer concentration of the polymerized dope was in the range of 5 to 30% by weight, there was little change in viscosity before and after standing for 5 days. When the stable polymerization dope is spun into the coagulation bath directly through the spinneret, polyamide fibers having high strength and high elasticity can be easily produced. It is also possible to produce a film using a solution casting method. On the other hand, the polymerized polymer solution may be mixed with a non-solvent such as methyl alcohol or water to obtain a pulp polymer, and the pulp obtained may be collected separately and stored in a "resin" form.

This resin can then be used for the production of moldings in the future. Since such resins have high solubility in polar organic solvents, the molded resin can be prepared by dissolving the stored resins in polar organic solvents, processing them to a desired shape, and drying or solidifying them.

The aromatic polyamide polymer and the aromatic polyamide dope according to the present invention do not contain sulfuric acid, so that the polymerization degree of the aromatic polyamide polymer is not lowered, and the production cost is increased due to the recovery of sulfuric acid due to the use of sulfuric acid, and the production by sulfuric acid Process problems such as plant corrosion and work hazards can also be addressed.

The present invention will be described in more detail with reference to Examples.

Example 1

Preparation of 1,4'-bis (4-amino phenylcarbox amido) cyanobenzene having a nitrile group in the aromatic nucleus

a) Preparation of 1, 4'-bis (4-nitro phenylcarbox amido) cyanobenzene

Under nitrogen stream, 500 g of dimethylacetamide (hereinafter referred to as DMAc) was dissolved in 13.3 g (0.1 mole) of 6-cyanoparaphenylenediamine while stirring with a mechanical stirrer, and then cooled to 10 ° C. using a cooling bath. After cooling, 37.2 g (0.2 mol) of 4-nitrobenzoyl chloride was added while increasing the stirring speed.

Continue stirring for 4 days, then add DMAc to dissolve completely and filter. The highly viscous liquid obtained by filtering the filtered liquid was placed in distilled water, stirred, and solidified. The mixture was filtered, washed with water, washed with acetone, washed, filtered and dried in a vacuum oven at a temperature of 80 ° C. to obtain 1,4′-bis (4- Nitro phenylcarbox amido) 41.1 g of cyanobenzene was prepared. Yield 95%.

b) Preparation of 1, 4'-bis (4-amino phenylcarbox amido) cyanobenzene

While stirring 500 g of ethanol, 5 g of paradium / carbon (5%) and 10 g of 1,4'-bis (4-amino phenylcarbox amido) cyanobenzene were added and stirred at 85 ° C. using an oil bath. Then, the hydrogen pressure is maintained at a pressure of 4Kg and allowed to stand for 24 hours. After completion of the reaction, the resultant was filtered and the solid separated was dissolved in acetone again and re-filtered to separate paradium / carbon (5%). The solution was recrystallized from activated carbon, and then recrystallized using a Soxhlet apparatus with acetone and ethanol ratio of 1: 1. The solution was separated and dried to obtain 1,4'-bis (4-amino phenylcarbox amido). 7.68 g of cyanobenzene is prepared. The yield is 92%.

c) preparation of aromatic polyamide polymerization dope

100 g of dimethylacetamide (DMA c) and 2 g of LiCl were added to a fully dried three-necked flask under nitrogen stream, followed by stirring, followed by 12.93 g of 1,4'-bis (4-amino phenylcarboxamido) cyanobenzene. To dissolve completely.

After maintaining the temperature of the solution at 10 ° C., 7.07 g of terephthaloyl chloride (TPC) was added at once with vigorous stirring to prepare a viscous aromatic polyamide polymerization dope. Water is added to the polymerization dope to precipitate the polymer to recover the polymer. The intrinsic viscosity of the produced aromatic polyamide polymer is 7.2.

Examples 2-11

An aromatic polyamide polymerization dope was prepared in the same manner as in Example 1 except that the amount of the polymerization monomer, the inorganic salt and the polymerization solvent was changed as shown in Table 1.

Example 12

An aromatic polyamide polymerization dope was prepared in the same manner as in Example 1 except that 2 g of CaCl ₂ was added instead of LiCl used in preparing the aromatic polyamide polymerization dope.

Example 13

An aromatic polyamide polymerization dope was prepared in the same manner as in Example 1 except that 4 g of CaCl ₂ was added instead of LiCl used in preparing the aromatic polyamide polymerization dope.

Table 1 shows the results of evaluating the intrinsic viscosity and solution stability of the aromatic polyamide polymerization dope prepared in Examples 1 to 13.

The intrinsic viscosity and the stability evaluation method of the solution dope are as follows.

Inherent Viscosity (Inherent Viscosity: I.V)

Where C is the concentration of the polymer solution (0.5 g dissolved in 100 ml of 95-98% concentrated sulfuric acid) and the relative viscosity Is the ratio of the flow time measured with a capillary viscometer at a temperature of 30 ° C., and the solvent is 95% to 98% concentrated sulfuric acid.

Solution Dope Stability

After the polymerization dope was prepared for 5 days at room temperature, the intrinsic viscosity was measured and compared with the initial intrinsic viscosity.

The aromatic polyamide polymer of the present invention is excellent in solubility in polar organic solvents without deterioration in heat resistance and strength. Therefore, a polar organic solvent may be used instead of sulfuric acid as a solvent when preparing a polymerization dope for forming a molding.

Since the aromatic polyamide polymerization dope of the present invention does not contain sulfuric acid, there is no degradation of the polymer, and the problem of corrosion of the manufacturing equipment and process risks due to the use of sulfuric acid can be solved.

Claims (17)

An aromatic polyamide polymer having a repeating unit of the following formula (I). Wherein R is And R 'is A represents, X is an alkoxy group having 1 to 4 carbon atoms or an alkyl group of CN, Cl, Br, I, NO 2, 1 to 4 carbon atoms, n is an integer from 10-100000. An aromatic polyamide polymer having a repeating unit of formula (I) according to claim 1, characterized in that it is soluble in polar organic solvents. Aromatic poly having a repeating unit of the following formula (I) characterized by reacting an aromatic diamine compound of formula (II) with an aromatic dieside compound of formula (III), optionally under a polymerization solvent containing an inorganic salt Process for the preparation of amide polymer. In formulas (I) to (III), R is And R 'is X is CN, Cl, Br, I, NO ₂ , an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms, n is an integer of 10 to 100,000, Y is F, Cl, Br, I And halogen elements. The process for producing an aromatic polyamide polymer according to claim 3, wherein the polymerization temperature is 0 to 50 ° C. The method for producing an aromatic polyamide polymer according to claim 3, wherein the polymerization solvent is an amide organic solvent, a urea organic solvent or a mixed solvent thereof. The process according to claim 3 or 5, wherein the polymerization solvent is N-methyl-2-pyrrolidone (NMP), N, N-dimethylacetamide (DMAc), hexamethylphosphoamide (HMPA), N, N, N ' , N'-tetrasulfoxide (DMSO) or a mixture thereof. The method of claim 3, wherein the inorganic salt is at least one compound selected from the group consisting of CaCl ₂ , LiCl, NaCl, KCl, LiBr and KBr. The method for producing an aromatic polyamide polymer according to claim 3 or 7, wherein the inorganic alkali compound is contained in an amount of 5% by weight or less based on the total amount of the polymerization solvent. The method for producing an aromatic polyamide polymer according to claim 3, wherein the aromatic diamine compound of formula (II) is 1,4'-bis (4-amino phenylcarbox amido) cyanobenzene. The method for producing an aromatic polyamide polymer according to claim 3, wherein the aromatic dieside compound of formula (III) is terephthalic acid chloride. A wholly aromatic polyamide polymerization dope comprising 5 to 30% by weight of an aromatic polyamide polymer having a repeating unit of the formula (I) and 70 to 95% by weight of a polar organic solvent optionally containing an inorganic salt. Wherein R is And R 'is A represents, X is an alkoxy group having 1 to 4 carbon atoms or an alkyl group of CN, Cl, Br, I, NO 2, 1 to 4 carbon atoms, n is an integer from 10-100000. The organic solvent according to claim 11, wherein the polar organic solvent is N-methyl-2-pyrrolidone (NMP), N, N-dimethylacetamide (DMAc), hexamethylphosphoamide (HMPA), N, N, N ', N '-Tetrasulfoxide (DMSO) or mixtures thereof, characterized in that the wholly aromatic polyamide polymerization dope. The wholly aromatic polyamide polymerization dope according to claim 11, wherein the inorganic salt is at least one compound selected from the group consisting of CaCl ₂ , LiCl, NaCl, KCl, LiBr and KBr. A method for producing a wholly aromatic polyamide polymerized dope, wherein the aromatic polyamide polymer having a repeating unit of the following formula (I) is selectively dissolved in a polar organic solvent containing an inorganic salt. Wherein R is And R 'is A represents, X is an alkoxy group having 1 to 4 carbon atoms or an alkyl group of CN, Cl, Br, I, NO 2, 1 to 4 carbon atoms, n is an integer from 10-100000. The method for producing a wholly aromatic polyamide-polymerized dope according to claim 14, wherein the content of the dope of the aromatic polyamide polymer having a repeating unit of the formula (I) is 5 to 30% by weight. The method of claim 14, wherein the polar organic solvent is N-methyl-2-pyrrolidone (NMP), N, N-dimethylacetamide (DMAc), hexamethylphosphoamide (HMPA), N, N, N ', N '-Tetrasulfoxide (DMSO) or mixtures thereof. The method according to claim 14, wherein the inorganic salt is N-methyl-2-pyrrolidone (NMP), N, N-dimethylacetamide (DMAc), hexamethylphosphoamid (HMPA), N, N, N ', N '-Tetrasulfoxide (DMSO) or a mixture thereof, a method for producing a wholly aromatic polyamide polymerization dope.