KR0144089B1 - Aromatic polyamide pulp and method of manufacturing thereof - Google Patents

Abstract

The present invention relates to an aromatic polyamide pulp by adding and dissolving an inorganic salt or a mixture of a small amount of a Lewis acid compound in an amide solvent, a urea polymerization solvent or a mixed solvent thereof, and then reacting the aromatic diamine with an aromatic dieside chloride. It relates to a process for the preparation of polymers and orientations by means of a stirrer in a continuous polymerization-orientation-gelling device in a short time without the use of tertiary amines, which are expensive and harmful to humans, and regardless of isotropic or anisotropic and continuous or discontinuous discharge. It is possible to maximize the molecular orientation, which is an essential element for pulping, as well as to produce pulp with excellent physical properties.

Description

Aromatic Polyamide Pulp and Method for Making the Same

1 is a schematic diagram of an open batch batch polymerization-orientation-gelling apparatus used in the present invention.

FIG. 2 is an enlarged view of the stirrer configured in the batch polymerization-orientation-gelling apparatus shown in FIG.

FIG. 3 is a longitudinal sectional view of the reaction vessel constituted in the batch polymerization-orientation-gelling apparatus shown in FIG.

4 is a state diagram of the reactants in the preparation of the primary polymer solution

5 is a state diagram of the reactants in the preparation of the secondary polymer solution

* Explanation of symbols for main parts of the drawings

1: Continuous mixer 2: Agitator

3: rotating shaft 4: driving motor

5: Wing of the stirrer 6: heating wire

7: stopper 8: discharge outlet

A: 1 primary aromatic dieside chloride B: diamine solution

C: Secondary Aromatic Diesidechloride D: 1 Primary Polymer Solution

The present invention relates to a method for producing an aromatic polyamide pulp, and more specifically, to an amide solvent, a urea polymerization solvent, or a mixed solvent thereof, an inorganic diamine or a mixture of a small amount of a Lewis acid compound is added and dissolved to form an aromatic diamine. And a method for producing an aromatic polyamide pulp having excellent physical properties by reacting with an aromatic dieside chloride.

Conventionally, a method for producing aromatic polyamide pulp using a mixed solvent obtained by adding an inorganic salt and a tertiary amine to an amide solvent as a technique for producing aromatic polyamide pulp is known from US Patent No. 4,511,623. In the above method, an aromatic diamine and an aromatic dieside chloride are added to an polymerization solution in which an inorganic salt and a tertiary amine are added to an amide solvent, followed by rapid shearing force before stirring and gelation, and left to stand to further increase intrinsic viscosity to prepare pulp. However, in the case of preparing the aromatic polyamide of high polymerization degree by the above method, the polymerization reaction proceeds rapidly by adding the added tertiary amine and the aromatic dieside chloride once so that the gelation occurs within a few seconds, so that the batch formula Not only is the process control difficult in polymerization, but it is also very difficult from the industrial point of view to manufacture pulp by continuous polymerization, and high molecular weight pulp with fibril is developed because the molecular chain exhibits an isotropic orientation without molecular orientation during gelation. In order to prepare the problem that must be left or aged for at least 5 hours after polymerization have.

In addition, Korean Patent Publication No. 92-4154 describes a process for aging by discharging anisotropic polymer solution prior to gelation into a container continuously, but in the above process, in the case of an isotropic polymer solution, the final physical properties are deteriorated due to the powder state rather than pulp. In addition, even in the case of an anisotropic polymer solution, in order to be anisotropic, it must have a certain viscosity or more, which is likely to cause gelation, which causes considerable difficulty in the manufacturing process. In addition, in order to increase the intrinsic viscosity and orientation of the polymer during aging, a long time of 0.5 to 5 hours is required, and the molecular orientation due to its own characteristics is smaller than that of artificially stirring to orient the microfibrils of the final pulp. Low, even in the pulping process has a low molecular orientation has a problem in that it takes a long time to develop the same level of microfibrils.

In addition, Korean Patent Publication No. 90-4911 and many other patents disclose that a liquid crystal prepolymer having a certain viscosity (intrinsic viscosity) before gelation is extruded through a unit as an alignment device and sprayed or contacted with a tertiary amine solvent. Although a method for producing pulp has been proposed, in the above method, when a unit that is an alignment device is used, a solution of polymer is gelled from the wall of the unit, and the alignment device is clogged, thus making the process difficult.

Aromatic polyamide pulp is generally prepared using a batch polymerization process. For example, a pulp is prepared by mixing, stirring and polymerizing a polymerization solvent, a monomer and the like in one reaction vessel. This batch polymerization method has the advantages of the physical properties of the resulting pulp, but because of the discontinuous, there is a disadvantage such as low productivity and high production cost.

Therefore, in order to impart continuity to the production of the aromatic polyamide pulp, it may be considered that many reaction vessels are sequentially arranged, but this method makes it difficult to obtain a polymer of a certain physical property, and the productivity is reduced, and also the contents in the reaction vessel. In order to remove the lid, the lid of the container must be opened and closed. The stirrer, the polymerization solvent inlet tube, the monomer inlet tube, and various installation lines are connected to the lid, so the opening and closing of the lid is almost impossible.

Therefore, in view of the above-mentioned problems of the prior art, the present invention does not use expensive tertiary amines, and further increases the degree of polymerization and orientation while completely eliminating the problem of solidifying the process line by gelation, thereby further increasing the degree of pulping. It is an object of the present invention to make aromatic polyamide pulp having excellent physical properties at low production cost by facilitating a continuous manufacturing process.

According to the present invention attaining the above object, a homopolymer or copolymer having a repeating unit represented by the following structural formula (I) or (II), comprising the following steps (a) to (j) Processes for the preparation of aromatic polyamide pulp in the form are provided:

(a) preparing a polymerization solvent by adding an inorganic salt alone or a mixture with a Lewis acid compound to an amide organic solvent, a urea organic solvent or a mixed solvent thereof;

(b) dissolving aromatic diamine in the polymerization solvent to prepare a diamine solution,

(c) preparing a primary polymer solution by adding 20 to 50% by weight of 100% by weight of the total amount of aromatic dieside chloride to be reacted in an equimolar amount with the aromatic diamine to the diamine solution,

(d) adding a remaining weight percent of the aromatic dieside chloride to the primary polymer solution and mixing the same to prepare a secondary polymer solution,

(e) After discharging the secondary polymer solution into an open batch polymerization-orientation-gelling device consisting of a stirrer and a reaction vessel, the polymer solution is polymerized and oriented before gelation using a stirrer and left for a predetermined time. Gelling to a degree that is separated from the stirrer and the reaction vessel,

(f) separating the gelled polymer from the stirrer and the reaction vessel,

(g) cutting the separated polymer into suitable sizes,

(h) aging the cleaved polymer at a predetermined temperature until solidified,

(i) immersing the solidified polymer in a coagulation solution to extract a polymerization solvent, and

(j) pulverizing the polymer from which the polymerization solvent is extracted in a pulping apparatus, followed by washing with water and drying.

(In the formula, R ₁ , R ₂ , R ₃ are each any one aromatic group selected from the following,

In the aromatic groups, X is hydrogen, chlorine, bromine, iodine or an alkyl or alkoxy group having 1 to 4 carbon atoms, and Y is

Hereinafter, with reference to the accompanying drawings illustrating a preferred embodiment of the present invention will be described in more detail the present invention.

According to the present invention, the input of the polymerization solvent, the monomer, and the like, which is a preliminary step of pulp production, is carried out in a continuous process, and the final polymerization, orientation and gelation are performed in an open batch batch polymerization-orientation-gelling apparatus. After a certain period of time after gelling, the entire polymer becomes a soft gelled state due to the viscosity. When the stirrer and the reactor are separated from the polymer, the polymer does not adhere to the surface of the stirrer or the reaction vessel. In the batch polymerization-orientation-gelling apparatus, polymerization and orientation can be maximized by using a general blade-shaped stirrer, thereby maximizing molecular orientation, which is essential for pulping, and producing pulp with a constant physical property. .

Hereinafter, the present invention will be described in more detail for each process.

The polymerization solvent used in the production of the aromatic polyamido pulp of the present invention is prepared by adding an inorganic salt alone or a mixture with a Lewis acid compound to an organic solvent.

As such an organic solvent, an amide organic solvent, a urea organic solvent or a mixed organic solvent thereof can be used. Specific examples thereof include N-methyl-2-pyrrolidone (NMP), N, N-dimethylacetamide (DMAc), hexamethylphosphoramide (HMPA), N, N-dimethylformamide (DMF), N, N, N ', N'-tetramethylurea (TMU) or mixtures thereof.

The inorganic salt contained in the polymerization solvent of the present invention is for increasing the solubility of the polymer, and examples thereof include halogenated alkali metal salts or alkaline earth metal salts such as CaCl ₂ , LiCl, 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 thereof. The addition amount of the inorganic salt is preferably 12% by weight or less relative to the total amount of the polymerization solvent, and when the addition amount exceeds 12% by weight, no further effect can be expected and it becomes uneconomical.

In addition, a small amount of Lewis acid compounds may be added to the polymerization solvent in addition to the inorganic salt in order to further increase the solubility of the polymer. The Lewis acid-based compound is preferably selected from halogen elements and transition metal compounds, or compounds in which halogen elements and group IIIA, IVA, VA or VIA elements of the periodic table are combined. Representative examples of such Lewis acid compounds include BF ₃ , BCl ₃ , AlCl ₃ , MgCl ₃ , FeCl ₂ , FeCl ₃ , ZnCl ₂ , SbCl ₂ , HgCl ₂ , and the like. It is preferable to mix the Lewis acid compound in the range of 0.1 to 5% by weight based on the total amount of the polymerization solvent. When the addition amount is less than 0.1% by weight, the solubility of the final polymer is increased and the molecular weight is higher than that of the inorganic salt alone. It is difficult to expect an increase effect, and when the addition amount exceeds 5% by weight, there is an effect of increasing solubility and molecular weight, but it is uneconomical.

When the inorganic salt is mixed with the polymerization solvent alone, the intrinsic viscosity of the pulp is increased by increasing the solubility during the polymerization process when the inorganic salt and the Lewis acid compound are mixed based on the same content.

According to a preferred embodiment of the present invention, after the polymerization solvent is prepared, the aromatic diamine solution is prepared by dissolving the aromatic diamine in the polymerization solvent, and using the quantitative supply and the temperature control device, etc. At the same time, 20-50% of the total amount of the aromatic dieside chloride to be reacted in an equimolar amount with the aromatic diamine is first quantitatively and continuously supplied. It is preferable to keep the temperature of the primary polymer solution reacted with a part of the aromatic dieside chloride in the range of 0 to 30 ° C.

The primary polymer solution thus obtained is again supplied to a continuous mixer capable of temperature control at a constant amount and at a constant temperature using a device equipped with a quantitative supply and a temperature controller, and at the same time, the remaining 50 to 80% of the aromatic dieside chloride is A secondary polymer solution is prepared by quantitatively, continuously feeding, mixing, and reacting.

A continuous mixer is not necessary here. When the primary polymerization solution and the aromatic dieside chloride are directly added to the reaction vessel, the aromatic dieside chloride vapor in the molten state may rise to corrode the device. Therefore, it is effective to use a continuous mixer if possible. In a continuous mixer, the mixing-reaction time is sufficient to uniformly mix, that is, approximately 5 to 30 seconds.

On the other hand, when producing a primary polymer solution or a secondary polymer solution, it is preferable to add a reactant in the same direction as illustrated in FIG. 4 and FIG. Injecting the reactants in this manner is advantageous because the mixing is short and uniform. In FIG. 4 and FIG. 5, the tube (tube) in which the primary aromatic dieside chloride (A) or the secondary aromatic dieside chloride is introduced is wound by a hot wire, which is affected by the external temperature. It is to prevent the hardening. A continuous mixer is a system capable of mixing and discharging, which continuously produces a secondary polymer solution.

The secondary polymer solution uniformly mixed in the continuous mixer is discharged to the reaction vessel of the open batch polymerization-orientation-gelling apparatus regardless of continuous or discontinuous through the discharge port at the rear of the continuous mixer and polymerized until gelation by stirring using a stirrer. . In this way, the molecular orientation can be imparted as much as possible to increase the degree of polymerization and to rotate the stirrer. In the present invention, the reason for the polymerization and orientation by stirring until gelation is that if it is stirred until gelation, the polymer is pulverized and the molecular orientation worsens again.

In FIG. 1 a batch polymerization-oriented-gelling device is schematically shown. Each reaction vessel of the batch polymerization-orientation-gelling apparatus of FIG. 1 can be moved up and down and rotated, and the orbital movement of the reaction vessel about the rotation axis 3 can occur continuously or discontinuously. You can also adjust with. In addition, the rotational speed (rpm) of the stirrer drive motor 4 can also be adjusted. As shown in FIG. 3, the reaction vessel is preferably larger in diameter than the bottom so that the polymer is well separated. The number of the stirrer blades 5 may be one as shown in FIG. 2, and may be more than that.

The polymer stirred until gelation is allowed to stand for some time (approximately 5 minutes or more) without stirring until it gels to the extent that it is separated from the stirrer and reaction vessel.

After gelling in this way, the stirrer is first separated from the polymer, the reaction vessel is turned upside down to completely separate the polymer from the reaction vessel, and then cut to a suitable size.

Since the polymer separated from the reaction vessel is not yet solidified, there is a possibility that the degree of polymerization does not increase on the surface of the polymer when reacted with moisture in the air. The cleavage of the separated polymer is therefore advantageously carried out in an atmosphere that is as moisture free as possible.

After the polymer is cut, it is aged and solidified. The ripening temperature is appropriately 25 to 150 ℃. If the aging temperature is less than 25 ℃ aging takes too much time for the aging of the polymer, it is uneconomical, if the aging temperature exceeds 150 ℃, the intrinsic viscosity of the final pulp occurs. In this aging process, the molecular orientation is further increased as well as the intrinsic viscosity when the polymer is solidified.

After aging and solidification, the polymer is immersed in water or a mixed coagulation solution containing 0 to 40% by weight of a polymerization solvent and an inorganic salt to extract the polymerization solvent in the polymer. The extraction process of the polymerization solvent is necessary before the pulping process, because the pulping of the polymer without the extraction process lowers the physical properties of the pulp such as fibrillation.

As described above, the polymer from which the polymerization solvent is extracted is added with a large amount of coagulant in a pulping apparatus, pulverized and dried to prepare a desired polyamide pulp. At this time, the coagulant is used after neutralizing the mixed aqueous solution containing 0 to 40% by weight of the inorganic salt and the polymerization solvent extracted in the water or polymerization solvent extraction step. The reason for using such a mixed aqueous solution is that the physical properties of the final pulp tend to increase rather than using pure water only in the pulping apparatus.

In the present invention, the concentration of the polymer is suitably 3 to 15% by weight with respect to the polymerization solvent, and when the content is 3% by weight or less, a high intrinsic viscosity pulp can be prepared, but the concentration of the polymer is uneconomical, and the concentration of the polymer is more than 15% by weight. It is difficult to produce pulp with high intrinsic viscosity due to a decrease in solubility.

The aromatic polyamide pulp thus prepared has an intrinsic viscosity (IV) of not less than 3.5 g / mV obtained from the following formula (III) and a Canadian Standard Freeness of 250 measured by the method of TAPPI standard T227 om-85. It is about 500 ml.

I.V (g / ㎗) = ln (ηrel) / C (III)

{C is the concentration of the polymer solution (solution dissolved 0.5g of polymer in 100ml of 95-98% concentrated sulfuric acid), ηrel is the relative viscosity is the ratio of the flow time measured by a capillary viscometer at a temperature of 30 ℃, The solvent is 95-98% concentrated sulfuric acid.}

As described above, according to the present invention, the polymerization and polymerization are carried out by using a stirrer in a continuous polymerization-orientation-gelling apparatus in a short time without the use of tertiary amines which are expensive and harmful to the human body, and regardless of isotropic or anisotropic and continuous or discontinuous discharge. The high orientation can be easily given to the polymer, and the polymer can be spontaneously separated from the reaction vessel without any special force in the polymerized gel to give polymerization and maximum orientation in the development-system. This makes it possible to continuously produce polyamide pulp of excellent physical properties.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited by Examples.

Example 1

After adjusting the vessel containing 1000 kg of N-methyl-2-pyrrolidone to 80 ° C., 80 kg of CaCl ₂ was added, stirred, and dissolved to prepare a polymerization solvent. 48.67 kg of p-phenylene diamine was added to the polymerization solvent, followed by stirring and dissolution to prepare a diamine solution. The diamine solution thus prepared was adjusted to 5 ° C. using a metering feeder and a temperature controller, and then fed to the mixing device at 1128.67 g / min while supplying 27.41 g / min of terephthaloyl chloride in solution. To prepare a primary polymer solution (see FIG. 4).

The primary polymer solution was again adjusted to 5 ° C. using a temperature controller and fed to a continuous mixer at 1156.08 g / min using a metering feeder while simultaneously supplying 63.95 g / min of terephthaloyl chloride in solution. Mix for 10 seconds (see Figure 5). At this time, the temperature of the continuous mixer was adjusted so that the internal polymer temperature did not exceed 60 ℃.

The polymer solution polymerized under these conditions is discharged into a reaction vessel of an open type batch polymerization-orientation-gelling apparatus installed at the lower end of the discharge port as shown in FIG. 1, and then polymerized until stirring by stirring with a stirrer in the polymerization-orientation-gelling apparatus. And the polymer was separated from the container after it was orientated and left to gel for 5 minutes.

The polymer separated in the continuous transfer polymerization-orientation-gelling apparatus is cut to a suitable size, aged at 100 ° C. for 1 hour, immersed in water, and extracted with an appropriate amount of the polymerization solvent, and then pulverized, washed with water and dried in a pulping apparatus. Aromatic polyamide pulp was obtained.

The intrinsic viscosity of the obtained aromatic polyamide pulp was 4.8, and the Canadian standard freedom was 348 ml.

[Examples 2 to 7 and Comparative Examples 1 to 3]

The same procedure as in Example 1 was repeated except for changing some of the conditions as shown in Tables 1 and 2 below. Physical properties of the prepared aromatic polyamide pulp are shown in Table 3 below.

Claims (9)

A process for preparing an aromatic polyamide pulp in the form of a homopolymer or copolymer having a repeating unit represented by the following structural formula (I) or (II), comprising the following steps (a) to (j) :( a) preparing an polymerization solvent by adding an inorganic salt alone or a mixture with a Lewis acid compound to an amide organic solvent, a urea organic solvent or a mixed solvent thereof, and (b) dissolving an aromatic diamine in the polymerization solvent to diamine. Preparing a solution, (c) preparing a primary polymer solution by adding 20-50 wt% of 100 wt% of the total amount of aromatic dieside chloride to be reacted in an equimolar amount with the aromatic diamine in the diamine solution, (d) Injecting the remaining weight% of the aromatic dieside chloride in the primary polymer solution and mixed evenly to prepare a secondary polymer solution, (e) stirring the secondary polymer solution After discharging to an open batch polymerization-orientation-gelling apparatus consisting of a reaction vessel, the polymer solution is polymerized and oriented until gelation using a stirrer, and left for a predetermined time to gel the polymer to be separated from the stirrer and the reaction vessel. (f) separating the gelled polymer from the stirrer and the reaction vessel, (g) cutting the separated polymer to an appropriate size, and (h) ripening the cut polymer at a predetermined temperature until solidified. (I) immersing the solidified polymer in a coagulation solution to extract a polymerization solvent, and (j) pulverizing the polymer from which the polymerization solvent is extracted in a pulping apparatus, followed by washing and drying. (In the formula, R ₁ , R ₂ , R ₃ are each any one aromatic group selected from the following, In the aromatic groups, X is hydrogen, chlorine, bromine, iodine or an alkyl or alkoxy group having 1 to 4 carbon atoms, and Y is The method of claim 1, wherein each of the reactants in the same direction in the preparation of the primary polymer solution or the secondary polymer solution, characterized in that for producing an aromatic polyamide pulp. The method for producing an aromatic polyamide pulp according to claim 1, wherein the leaving time for gelling the polymer in the batch polymerization-orientation-gelling apparatus is 10 seconds or more and 5 minutes or less. The method for producing an aromatic polyamide pulp according to claim 1, wherein the aging temperature is 25 to 150 ° C. The method for producing an aromatic polyamide pulp according to claim 1, wherein the coagulating liquid is water or a mixed coagulation liquid of water and an organic solvent and an inorganic salt used for polymerization. The method for producing an aromatic polyamide pulp according to claim 5, wherein the total amount of the organic solvent and the inorganic salt in the coagulation solution is 40% by weight or less based on the total amount of the coagulation solution. The method of claim 1, wherein the aromatic polyamide is poly (para-phenylene terephthalamide). Prepared by the method comprising the following steps (a) to (g), characterized by the following structural formula (I) or (II) characterized in that the intrinsic viscosity is not less than 3.5g / ,, Canadian standard degree of freedom 250-500ml Aromatic polyamide pulp in the form of a homopolymer or copolymer having a repeating unit, comprising: (a) an inorganic salt alone or a mixture with a Lewis acid compound in an amide organic solvent, a urea organic solvent or a mixed solvent thereof, and then a polymerization solvent. (B) preparing a diamine solution by dissolving the aromatic diamine in the polymerization solvent, and (c) 20 to 100% by weight of the total amount of aromatic dieside chloride to react an equimolar amount with the aromatic diamine in the diamine solution. Preparing a primary polymer solution by adding 50% by weight, (d) adding the remaining weight% of aromatic dieside chloride to the primary polymer solution, and mixing the secondary (E) discharging the secondary polymer solution into an open batch polymerization-orientation-gelling device comprising a stirrer and a reaction vessel, and then polymerizing and orienting the polymer solution before gelation using a stirrer. (G) separating the gelled polymer from the stirrer and the reaction vessel, and (g) cutting the separated polymer into an appropriate size. (h) aging the cleaved polymer at a predetermined temperature until solidified, (i) immersing the solidified polymer in a coagulating solution to extract a polymerization solvent, and (j) extracting the polymerization solvent. Pulverizing the polymer in a pulping apparatus, followed by washing and drying. (In the formula, R ₁ , R ₂ , R ₃ are each any one aromatic group selected from the following, In the aromatic groups, X is hydrogen, chlorine, bromine, iodine or an alkyl or alkoxy group having 1 to 4 carbon atoms, and Y is 9. The aromatic polyamide pulp of claim 8 wherein said aromatic polyamide is poly (para-phenylene terephthalamide).