KR920006371B1 - Manufacturing process of aromatic polyamide fiber - Google Patents

Abstract

The preparing method of wholly aromatic polyamide fiber with excellent strength by combining two wholly aromatic polyamide pregolymers comprises; making 1st prepolymer solution of intrinsic viscosity of 1.0-3.0 by combining same mol terephthaloyldichloride with p-phyenylenediamine previously solubilized into amide solvent containing inorganic salt, adding 2nd prepolymer solution of intrinsic viscosity of 0.5-2.5 made by combining m- phenylenediamine with same mol isophthaloyldichloride in amide solvent to the 1st prepolymer to make single phase prepolymer spining dopes, expressed as -NG-Ar-NHCO-Ar'-CO- [or and Ar' are each phenyl group substituted on meta or para position; mol. ratio of meta/para is 5/95 - 55/45 , spinning them into polymerization accelerating coagulation bath containing pyridine only or mixture of pyridine and amide solvent.

Description

Method for producing aromatic polyamide fibers

The present invention relates to a method for producing an aromatic polyamide fiber, and more particularly, a high molecular weight wholly aromatic polyamide having excellent strength by kneading two aromatic polyamide prepolymer solutions prepared as two and using them as a single phase spinning solution. The present invention relates to a method for producing a fiber.

Conventionally, after mixing para-phenylenediamine or meta-phenylenediamine with terephthaloyldichloride or isophthaloyldichloride in an N-methyl-2-pyrrolidone or dimethylacetamide solvent, and copolymerizing water, A method for producing aromatic polyamide fibers by spinning with a coagulant liquid as a main component is described in Japanese Patent Application Laid-Open No. 57-22071, Japanese Patent Application Laid-Open No. 59-20763, and Japanese Patent Application No. 49-12120. In this case, the solubility of the polymer in N-methyl-2-pyrrolidone or dimethylacetamide solvent is lowered and spinning is less likely to occur. Therefore, the method is limited to a low molecular weight fiber manufacturing method. .

Accordingly, the present invention provides an aromatic polyamide fiber having excellent physical properties by adjusting the molecular weight of the polymer so as to be capable of spinning in order to solve the problems of the prior art, and increasing the molecular orientation and polymerization degree of the polymer in a coagulating solution made of tertiary amine. The purpose is to provide a way to.

Hereinafter, the present invention will be described in detail.

In the present invention, in the preparation of aromatic polyamide fibers by wet spinning a spinning dope made of a prepolymer into a molecular promoting coagulating solution through water, followed by washing with water, drying and heat treatment, para- previously dissolved in an amide solvent Phenylenediamine was mixed with an equimolar amount of terephthaloyldichloride to prepare a first prepolymer solution having an intrinsic viscosity of 1.0 to 3.0, and isophthaloyldichloride in an equimolar amount with meta-phenylenediamine in an amide solution. Was prepared by kneading a second prepolymer solution having an inherent viscosity of 0.5 to 2.5, and then preparing a single-phase prepolymer spinning solution represented by the following structural formula (I), and then polymerizing pyridine alone or a mixture of pyridine and amide solvent. It is characterized by a method for producing anti-aromatic polyamide fibers which are spun into a promoting coagulation solution.

-NH-Ar-Nl1CO-Ar'-CO- (I)

In the above formulae, Ar, Ar 'is a phenyl group substituted at meta or para position, and the molar ratio of meta / para is 5/95 to 55/45.

Referring to the present invention in more detail as follows.

The present invention is to prepare a first prepolymer by dissolving paraphenylenediamine in an amide-based solvent containing an inorganic salt, and then adding terephthaloyl dichloride to the reaction, and containing the inorganic salt as described above Dissolving meta-phenylenediamine in an amide solvent, and then adding isophthaloyl chloride and reacting to prepare a second prepolymer, and kneading the first prepolymer and the second polymer solution to form the structural formula A method of producing an aromatic polyamide fiber, comprising the step of obtaining the prepolymer spinning solution of (I) and wet spinning it onto a molecular promoter coagulating solution.

The present invention relates to an amide-based solvent, for example, an inorganic salt containing 0.5 to 15% by weight relative to NMP, DMAc, HMPA, DMF, DMSO and the like, for example, LiCl ₂ , CaCl ₂ , KCl, KBr, LiBr and the like. After dissolving phenylenediamine, terephthaloyldichloride was added in an equimolar amount while maintaining the temperature below 40 ° C. under a nitrogen atmosphere to react at room temperature to prepare a first prepolymer before gelation. It has 4 to 20% by weight of the total silver, and the intrinsic viscosity of the prepolymer is preferably 1.0 to 3.0, particularly 1.5 to 2.5.

On the other hand, after dissolving meta-phenylenediamine in the inorganic salt as described above containing 0.5 to 15% by weight with respect to the amide solvent as described above, isopre while maintaining the temperature below 40 ℃ under nitrogen atmosphere Tallowyl dichloride is added to react at room temperature to prepare a second prepolymer before gelation. At this time, the content of the polymer is 5 to 30% by weight in total, and the intrinsic degree of the prepolymer is preferably 0.5 to 2.5, particularly 1.0 to 2.0.

The first and second prepolymer solutions obtained in this manner are kneaded to prepare a single-phase prepolymer spinning solution represented by the above formula (I), which is then introduced into a cylinder with a temperature controller, and the nozzle diameter is 0.05 to 1.0. When the spinning solution is extruded into a molecular polymerization coagulation solution consisting of a tertiary amine or a tertiary amine containing an amide solvent as described above, the polymerization solution is continuously polymerized by molecular orientation polymerization. The molecular weight of the polymer is rapidly increased by the catalysis of the tertiary amine. For this reason, when the extruded fibrous polymer is wound at an appropriate speed, an aromatic polyamide fiber having a high degree of orientation is produced.

Here, the narrower the diameter of the nozzle, the easier the extraction of the spinning solution, the better reaction with the tertiary amine, and the longer the contact time with the spinning solution and the coagulating solution, the more advantageous, but the practical elongation of 0.1 to 300 seconds is good. (SSF) is 1-4, and spinning temperature is -10-45 degreeC, but it is preferable to maintain 0 degreeC-25 degreeC for economic reasons.

On the other hand, the aromatic polyamide fibers produced according to the present invention exhibits a property that the initial modulus increases within 30 to 200% when heat treated under tension, and is not only possible for the fibers, but also when the nozzle spacing is adjusted to produce a film. It becomes possible.

In the present invention, the measured value for the intrinsic viscosity can be obtained by the following equation.

Intrinsic Viscosity (IV) = l n ( n _rel ) / C (II)

Where C is the concentration of 0.5 g of polymer dissolved in 100 m1 of concentrated sulfuric acid (95-98%), and n _re1 is the flow time rate of the amide solvent and the spinning solution measured by the Ostwald viscometer at 30 ° C.

Hereinafter, the present invention will be described in more detail with reference to Examples.

Example 1

A four-necked flask was prepared and sufficiently passed through dry nitrogen. Then, 1200 ml of N-methyl-2-pyrrolidone was added and the temperature was raised to 100 ° C., and 27.0 g of calcium chloride was added to dissolve completely. Subsequently, 24.50 g (0.23 mol) of para-phenylenediamine was added to the solution, followed by adding 45.95 g (0.23 mol) of terephthaloyl dichloride while cooling using a cooling water bath, and reacting for 15 minutes while stirring at 3000 rpm. To prepare a first prepolymer (A). At the same time, 1200 ml of N-methyl-2-pyrrolidone was added to four flasks in the same manner, the temperature was raised to 80 ° C, and 5 l.45 g (0.40 mol) of meta-phenylenediamine was completely dissolved. After cooling, 96.50 g (0.48 mole) of isophthaloyl dichloride was added thereto and reacted for 15 minutes while stirring at a rotational speed of 3,000 rpm to prepare a second prepolymer (B). Then, 50 g of the second prepolymer solution (B) was taken and kneaded with 950 g of the first prepolymer solution (A) to prepare an isotropic spinning solution. The spinning solution was transferred to a cylinder equipped with a 0.5 mm diameter, L / D l.0 detainer, spun into a pyridine coagulating solution, wound at 20 m / min, washed with water, dried, and aromatic polyamide fibers. Was prepared.

At this time, the intrinsic viscosity was 4.2, and E (elongation%) / T (tensile strength g / d) / Mi (initial modulus g / d) was 5.5 / 16/330.

[Examples 2 to 5]

In the same manner as in Example 1, but changing the mixing ratio of the first polymer solution (A) and the second polymer solution as shown in Table 1 below is shown in Table 1.

Table 1

Comparative Example 1

After completely passing dry nitrogen through a four-necked flask to completely remove moisture, 1200 m1 of N-methyl-2-pyrrolidone was added thereto, the temperature was raised to 100 ° C, and 49 g (0.46 mol) of para-phenylenediamine and 2.58 While completely dissolving g (0.02 mole) of meta-phenylenediamine and cooling with a cooling water bath, 91.90 g (0.23 mole) of terephthaloyldichloride and 4.83 g (0.02 mole) of isophthaloyldichloride were added and rotated. After reacting for 20 minutes while stirring the speed at 3000 rpm, 25 g of LiCl ₂ was added to prepare a spinning solution. The thus obtained product was transferred to a cylinder equipped with a mold having a diameter of 0.5 mm and L / D 1.0, and then spun into a water coagulation liquid and wound at a speed of 25 m / min, and the resulting fiber was washed with water and dried to prepare an aromatic polyamide fiber. It was.

At this time, the intrinsic viscosity is 4.2 and E (elongation%) / T (tensile strength g / d) / Mi (initial modulus g / d) = 5.4 / 8/180.

[Comparative Examples 2 to 5]

The mixing ratio of para-phenylenediamine and equimolar amount of tetraphthaloyldichloride and metaphenylenediamine and equimolar amount of isophthaloyldichloride was changed in the same manner as in Comparative Example 1. Table 2 is as follows.

TABLE 2

[Examples 6 to 9]

The results of the same method as in Example 1 while changing the composition of the coagulation solution are shown in Table 3 below.

Table 3

Claims (1)

In the preparation of the aromatic polyamide fibers by wet spinning the prepolymer spinning dope into a molecular promoting coagulating solution through a detention, and then washing with water, drying, and heat treatment, para-dissolved in an amide solvent containing an inorganic salt in advance Equimolar amount of terephthaloyldichloride was mixed with -phenylenediamine to prepare a first prepolymer solution having an intrinsic viscosity of 1.0 to 3.0, and isophthaloyldi in an equimolar amount with meta-phenylenediamine in an amide solvent. The second prepolymer solution having an intrinsic viscosity of 0.5 to 2.5 obtained by mixing chlorides was kneaded to prepare a single phase prepolymer spinning solution represented by the following structural formula (I), and then a pyridine alone or a molecule mixed with a pyridine and an amide solvent. A method for producing an aromatic polyamide fiber, characterized in that it is spun into a polymerization accelerator coagulating solution. -N H-Ar-NHCO-Ar '-CO-(I) In the above formulae, Ar and Ar 'are phenyl groups substituted in meta or para position, and the molar ratio of meta / para is 5/95 to 55/45.