KR20000046088A - Method for preparing modified polyamide 6 fiber containing benzene ring structure - Google Patents

Abstract

PURPOSE: A method for preparing polyamide 6 fiber which can be stably spun by improving the melt stability of the polymer and inhibiting the generation of carbides from monomer and oligomer when the polyamide is spun for a long time is provided. CONSTITUTION: A method for preparing modified polyamide 6 fiber containing benzene ring structure according to the present invention comprises preparing a polymer by melting and reacting caprolactam at 240 to 290°C using water as an initiator wherein an aromatic dicarboxylate compound in the amount of 0.1 to 2.0 wt% as a chain modifier is added before the polymerization reaction and a metal compound is added thereto.

Description

Process for preparing modified polyamide 6 fibers containing benzene ring structure

The present invention relates to a process for producing modified polyamide 6 fibers containing a benzene ring structure, and more particularly, to producing polyamide 6 by polymerizing caprolactam, using water as an initiator and aromatic dicar as chain regulator. The present invention relates to a method for producing modified polyamide 6 fiber having excellent melt stability and improved spinning property by adding an excess of carboxyl terminal to the amine terminal using a carboxylate and adding a magnesium compound before or during polymerization.

Conventionally, acetic acid is generally used as a terminal blocker of a chain structure in the preparation of polyamide 6 for fiber. Such acetic acid is used to block the amine end of the polymer to optimize the molecular weight to stabilize physical properties during spinning. Not only does it have a problem of low efficiency due to scattering when it is polymerized to boiling point, but also has a stabilizing effect on general spinning below 4,000m / min of spinning speed. Is promoted to cause problems such as difference in physical properties between yarns, trimming, and lowering of stretchability.

Therefore, the modification of the polymer is urgently required to obtain high-speed spinning and high efficiency. For this modification, the crystal structure of the polymer is finely mixed with or alone with mono or dicarboxylic acid, mono or diamine having good reactivity with caprolactam. It is proposed to make a modification.

However, this method has excellent viscosity stabilization effect in general spinning, but it does not reach a substantial equilibrium state as it folds at high speed during high speed spinning, which in turn facilitates the decomposition of the polymer, thereby causing the difference in physical properties, trimming and elongation between the radiators. There is a problem that is not suitable for high-speed spinning, such as causing a decrease.

Therefore, in order to manufacture the yarn at a high speed, it is necessary to improve the stabilization of the polymer, and to do so, it is necessary to have an excess of carboxyl ends relative to the amine ends to suppress thermal decomposition from the amine ends.

U.S. Patent No. 2,174,527 discloses a method for stabilizing a polymer by blocking the amine end with an excess of dicarboxylic acid in a diacid-diamine polyamide, and U.S. Pat. A method of polymerization using a chain extender is shown.

In addition, U.S. Patent No. 3,386,967 has a high molecular weight of 25,000 to 40,000 with a number average molecular weight of 25,000 to 40,000 through a multi-step process using 0.1 to 0.7 mole percent dicarboxylic acid, namely adipic acid, sebacic acid, dodecanediol acid and terephthalic acid. A method of preparing a polymer is disclosed, and US Pat. No. 3,839,530 discloses a method of using dicarboxylic acid anhydride as a chain regulator, but the compound is relatively volatile and difficult to maintain.

More recently, U. S. Patent No. 5,149, 758 uses terephthalic acid or isophthalic acid as a chain regulator in an amount of 0.1 to 0.6% by weight, with a total terminal content of 115 to 150 meq / kg and an amine terminal content of 25 meq / kg or more. A method for preparing an amide polymer is shown.

The conventional methods described above have the advantage of stabilizing the polymer by using dicarboxylic acid as a chain regulator of the polymer and obtaining a high-strength polyamide fiber, but the compound is dissolved in caprolactam which is a raw material of water and polyamide. Has a problem that is difficult to industrialize in the continuous production process of polyamide, such as precipitation or supplementation due to the very low or insoluble problem.

In addition, the polyamide made of the above-described compound has improved radioactivity and physical properties, but due to the carbide of volatile materials such as monomers and oligomers accumulated on the spinneret surface when melt spinning for a long time at high speed There is still a problem that poor workability of spinning at high speed still occurs, such as single cutting.

Carbide accumulated on the spinneret surface not only causes the bending of the molten polyamide during spinning, but also causes the bending to become larger, which causes the molten polyamide to adhere to the spinneret and ultimately cause single cutting. . Therefore, in order to produce a normal product, stop the spinning every certain time and clean the spinning nozzle will have the disadvantages of inconvenience and reduced productivity.

Particularly, in high-speed spinning, the effect of carbide generation is much higher than that of general spinning at low speed, and when the warping phenomenon of polyamide occurs, it leads directly to trimming, which causes a decrease in productivity and property irregularities.

An object of the present invention is to solve the above problems, to improve the melt stability of the polymer without the need for supplementation of existing equipment, and to suppress the generation of carbides by monomers and oligomers even during high-speed spinning of polyamide, It is to provide a method for producing polyamide 6 fibers that can stably spin.

That is, the present invention is to prepare a modified polyamide 6 fiber having a benzene ring structure, when the caprolactam is melted at 240 to 290 ℃ to prepare a polymer, water is added as an initiator 0.1 to 5% by weight compared to caprolactam And modifying the benzene ring containing an aromatic dicarboxylate compound as 0.1 to 2.0% by weight before the polymerization as a chain regulator, and adding 10 to 100 ppm to the metal atom before the polymerization or during the spinning. A method for producing polyamide 6 fibers.

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

First, the initiator is adjusted to 5% by weight or less according to the characteristics of the polymerization apparatus, and 0.1 to 2.0% by weight, preferably 0.2 to 1.0% by weight, of the aromatic dicarboxylate compound used as the chain regulator is added to the caprolactam raw material. To caprolactam raw material.

At this time, when the aromatic dicarboxylate is added in excess of 2.0% by weight, the degree of polymerization is remarkably lowered. Therefore, it is preferable to add less than 2.0% by weight in order to modify the polymer while maintaining an appropriate degree of polymerization.

As an aromatic dicarboxylate compound used as an initiator, it has a C1-C6 alkyl group or hydrogen group, for example, dialkyl terephthalate, dialkyl isophthalate, dialkyl naphthalate, terephthalic acid, isophthalic acid And the like, of which dimethyl terephthalate and dimethyl isophthalate are preferable from an industrial point of view.

By using such an aromatic dicarboxylate as a polymer chain regulator, it is possible to have an excess of carboxyl terminal relative to the amine terminal, and the total terminal content of the extracted and dried chips has 100 to 150 meq / kg. Since dyeing is an important item, it is preferable to have an amine terminal content of 30 to 60 meq / kg.

In the present invention, a magnesium compound is added to improve reactivity and to prevent bending and breakage caused by the flexibility of the yarn and melt spinning. Examples thereof include magnesium oxide, magnesium acetate, magnesium chloride, Magnesium stearate and the like, and the magnesium compound may be added before polymerization or upon spinning.

The magnesium compound used in the present invention is added at 10 to 100 ppm on the basis of magnesium element before polymerization or spinning, but when it is used below 10 ppm, the wiping period is insufficient to be extended, and when it is used above 100 ppm, the wiping extension period is good. One becomes unsuitable by causing a decrease of raw material property and chromaticity

Thus, by using the dicarboxylate and magnesium compounds in parallel as in the method used in the present invention, it is possible to obtain a polyamide fiber stable in high-speed spinning at the same time to obtain a melt stability and radioactive improvement effect without changing the existing equipment do.

Of course, the filaments produced by the above method may contain conventional additives and processing aids. For example, heat stabilizers such as copper (I) iodide and copper (II) acetate, light stabilizers using manganese (II), matting agents such as titanium dioxide, and the like, and antistatic agents include, for example, polyalkylene oxides and derivatives thereof. Can be used.

The additive can be added at any stage during the production of the filament yarn of the invention, but the stabilizer is preferably added at the beginning of the polymerization to achieve stabilization at the start. In addition, the moisture content of the manufactured chip is preferably less than 0.5% by weight, because if the moisture content is high, depolymerization occurs during spinning, resulting in poor sand quality in the final filament and causing workability deterioration.

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

Examples 1-4

First, in Examples 1 to 4, in order to measure the solubility of the chain regulator in the caprolactam raw material, the solubility was measured by dissolving each of the chain regulator in the caprolactam 1,000 g in an 80 ° C. thermostat until the maximum saturation. Recorded at 1.

Chain conditioner Solubility (%) 10% dissolution time Example 1 Dimethyl terephthalate 25% 10 Example 2 Dimethyl isophthalate 21% 12 Example 3 Terephthalic acid 15% 40 Example 4 Isophthalic acid 12% 45

As a result, the aromatic dialkyl carboxylate compound has better solubility than dicarboxylic acid, and also takes a short time to completely dissolve when added 10% of caprolactam, so that it can be added to existing processes without difficulty and precipitates. There is no advantage over carboxylic acids in mass production.

Examples 5-8 and Comparative Examples 1-3

A mixture was prepared by adding 100 parts by weight of caprolactam, 2 parts by weight of water as an initiator and a chain regulator as shown in Table 2, and adding magnesium compound at an initial stage of polymerization at 200 ppm to improve radioactivity.

The prepared mixture was placed in a polymerization reactor and polymerized at 265 ° C. for 4 hours. After removing the internal pressure and reacted for 2 hours at a reduced pressure of 480 Torr to prepare a polyamide 6 chip. Each polyamide prepared was to have a similar relative viscosity of 2.55 levels, and the polymerization properties were shown in Table 2.

After extracting and drying the obtained polyamide 6 chip, it was spun under a condition of a spinning temperature of 270 ° C. and a discharge amount of 38 g / min through a spinneret made of SUS-316 having 24 0.25 mm Φ holes in a 400 mm Φ extruder. Cooling the air at 20 ° C. while blowing at an air velocity of 0.6 m / min to impart an emulsion, and then wound up at a rate of 5500 m / min to obtain 70d / 24f yarn. In addition, the properties of the filaments obtained and the short break generation time are compared to each shown in Table 2 below.

Example 5 Example 6 Example 7 Example 8 Comparative Example 1 Comparative Example 2 Comparative Example 3 Polymerization condition Chain conditioner DMT DMI TPA IPA PA SA HA Input content (% by weight) 0.40 0.40 0.25 0.25 0.20 0.20 0.10 Relative Viscosity (RV) 2.44 2.46 2.45 2.43 2.45 2.43 2.43 Extract content (%) 9.8 10.0 10.3 10.8 11.3 11.9 11.9 After extraction and drying Relative Viscosity (RV) 2.52 2.54 2.51 2.54 2.56 2.55 2.59 Amine group (A) (meq / kg) 41 40 22 45 45 45 50 Carboxyl group (C) (meq / kg) 69 68 81 63 68 80 60 Overall end (A + C) (meq / kg) 110 108 103 108 108 101 101 After spinning Radio workability (%) 95 90 80 82 65 70 40 Strength (g / d) 5.56 5.52 5.56 5.53 5.45 5.42 5.42 Elongation (%) 36 35 34 35 35 33 33 Single trimming occurrence time (hrs) 51 48 40 41 36 40 23 Scene defects (/ 100km) 0.26 0.29 0.36 0.36 1.26 0.90 1.50

Note) 1.TPA: terephthalic acid IPA: isophthalic acid

PA: propionic acid SA: sebacic acid

HA: Acetic acid DMT: Dimethyl terephthalate

DMI: Dimethyl Isophthalate

2. The unit of terminal content (A or C) is meq / kg.

3. Relative Viscosity (RV) is measured at 25 ° C of 1 g of polymer per 100 ml of 95% sulfuric acid.

As shown in Table 2, by using a dicarboxyl compound having a benzene ring structure as a chain control agent, it was possible to obtain a high strength filament, and can also be a good result defect than the comparative example.

Examples 9-12 and Comparative Examples 4-6

In Examples 5 to 8 and Comparative Examples 1 to 3, a magnesium compound was added as a second additive during the polymerization of 30% by weight in order to improve the radioactivity.

Example 9 Example 10 Example 11 Example 12 Comparative Example 4 Comparative Example 5 Comparative Example 6 Polymerization condition Chain conditioner DMT DMI TPA IPA PA SA HA Mg Compound (ppm) 30 30 30 30 30 30 30 After spinning Radio workability (%) 100 100 90 92 75 80 60 Strength (g / d) 5.56 5.52 5.56 5.53 5.45 5.42 5.42 Elongation (%) 36 35 34 35 35 33 33 Single trimming occurrence time (hrs) 61 58 50 51 36 40 23 Scene defects (/ 100km) 0.16 0.19 0.26 0.26 0.86 0.70 1.50

As can be seen from Table 3, both Examples and Comparative Examples were added to the magnesium compound to reduce the radioworkability, the canonical defects, and the occurrence of short cuts, but also shows that the Example is superior to the Comparative Example.

Example 13 and Comparative Example 7

As shown in Table 4, dimethyl terephthalate was used as a chain regulator and a magnesium compound was added to the initial stage of polymerization to improve radioactivity, and polyamide 6 polymer was added at 265 ° C. at 4500 m / min and 6000 m /, respectively. Spin at min.

The relative viscosity (RV) of the prepared filament was 2.51, and the linear density was 70d / 24f. The results are shown in Table 4 below.

Note) 1.DMT: Dimethyl Terephthalate

2. Relative Viscosity (RV) is measured at 25 ° C of 1 g of polymer per 100 ml of 95% sulfuric acid.

As shown in Table 4, in the case of Comparative Example 7 shows the phenomenon that the occurrence frequency of single cutting significantly increased with increasing the spinning speed, in the case of Example 13 added in combination with magnesium compound, single yarn and It can be seen that the canonical defect is markedly reduced.

As described above, an aromatic dicarboxylate is used as a chain regulator during polyamide polymerization to have an excess of carboxyl terminal relative to the amine terminal, and a magnesium compound is used in parallel at the initial stage of polymerization or spinning to achieve a high speed of 6000 m / min. Excellent spinning workability in spinning, carbide adhesion to the spinneret surface is reduced, so that the occurrence of short-breaks is significantly reduced, it has an excellent effect in terms of productivity.

Claims (7)

In preparing a modified polyamide 6 fiber having a benzene ring structure, water is used as an initiator when melting the caprolactam at 240 to 290 ° C. to prepare a polymer, and an aromatic dicarboxylate compound is used as a chain regulator to 0.1 to A method for producing a modified polyamide 6 fiber containing a benzene ring structure, which is added before polymerization at 2.0% by weight and a metal compound is added thereto. The method for producing modified polyamide 6 fiber containing benzene ring structure according to claim 1, wherein water as the initiator is added at 0.1 to 5% by weight. The method for producing modified polyamide 6 fiber containing benzene ring structure according to claim 1, wherein the amount of the dialkyl carboxylate as the chain regulator is 0.2 to 1.0% by weight. The method for producing modified polyamide 6 fiber containing benzene ring structure according to claim 1 or 3, wherein the dialkyl carboxylate has an alkyl group having 1 to 6 carbon atoms or a hydrogen group. [Claim 2] The modified polyamide 6 fiber containing benzene ring structure according to claim 1, wherein the metal compound is a magnesium compound, which is added at the initial stage of polymerization or spinning at a concentration of 10 to 100 ppm based on the elemental magnesium. Manufacturing method. The method of claim 5, wherein the magnesium compound is one or two selected from magnesium oxide, magnesium acetate, magnesium chloride, and magnesium stearate. The method of claim 1, wherein the amine terminal content of the extracted chip has a 30 to 60 meq / kg, the total terminal content of 100 to 150 meq / kg to prepare a modified polyamide 6 fiber containing a benzene ring structure Way.