KR100193939B1 - How to make nylon 46 multifilament - Google Patents

Abstract

1. The technical field to which the invention described in the claims belongs

A method for the production of nylon 46 multifilament yarns having thermal dimensional stability characteristics that inhibited spherical formation and growth.

2. The technical problem that the invention tries to solve

Inhibition of excessive spheroid formation, the core of yarn during melt spinning of nylon 46 filament yarn

3. Summary of the Solution of the Invention

After melt spinning above the crystallization temperature, it passes through the heating hood, and then cools with an inert gas and stretches.

4. Important uses of the invention

Sewing thread rubber reinforcement and industrial material fiber

Description

How to make nylon 46 multifilament

1 is an atmosphere temperature for each emission region.

2 is a schematic configuration diagram according to the present invention.

3 is a cross-sectional view taken along line AA of the present invention.

4 is an enlarged configuration diagram of the third view of the present invention.

* Explanation of symbols for main parts of the drawings

1: detention 2: heating hood

3: low temperature inert gas 4: quenching part

5: low temperature outlet 6: perforated plate

7: mesh filter 8: nonwoven filter

9: heat insulation

The present invention relates to a method for producing a nylon 46 multifilament yarn (hereinafter referred to as nylon 46) having thermal dimensional stability characteristics in which spherical formation and growth are suppressed.

Nylon 46, represented by polytetraadipamide, has a high melting temperature of 270 ° C. or higher, so that thermal deterioration occurs severely when melted, and the crystallization rate is high, resulting in excessive formation and growth of crystallites, which are cores of the yarn. Processing into fibers is difficult, and such a phenomenon is particularly difficult to have poor stretchability and thermal dimension stability characteristics in the manufacture of fibers.

The conventional technique proposed as a method for solving this problem is to melt-spin nylon 46 polymer at a spinning temperature of 300 ° C. or higher and 340 ° C. or lower, and to pass the heating hood 2 directly under the detention with a spinning atmosphere temperature of 300 ° C. or higher. Is applied in Japanese Laid-Open Patent Publication No. 59-88910, Japanese Patent Application Laid-Open No. 3-9204, and a nylon 46 non-drawn yarn having a relative viscosity of 2.7 or more. A two-stage stretching method has been proposed in which the hot plate temperature of the secondary stretching region is 240 ° C or higher, the roller temperature following the hot plate is 220 ° C or higher, and the contact time between the yarn and the heating body is 0.4 seconds or more.

Although the above method solves the specificity of the high-melting nylon 46 polymer and the problems caused by it, in the former case, the method of inhibiting crystallization by inhibiting the occurrence of the spherical properties of the nylon 46 polymer is prevented. When the heating hood 2 is installed at a spinning atmosphere temperature of 300 ° C. or higher, a low viscosity of the molten polymer and decomposition due to rapid deterioration may cause a dropping phenomenon in which the polymer flows like water, resulting in cuts during stretching. Increasing the occurrence of the moor is a problem of economic efficiency and workability, and there is a problem in the crystallization delay, suppression by the conventional method by adjusting the length of the heating hood (2).

This is because, due to the different discharge amount and take-up speed per spinneret depending on the conditions, the passing and staying time of the thread in the heating hood 2 are different due to the change in the draft of the thread within the heating hood 2, so that the heat history received by the emission thread is different. As the crystallization progresses, the adverse effect of promoting spheroid growth is caused. In the latter case, thermal degradation occurs due to partial thermal degradation and recrystallization due to the temperature of the hot plate and the heat roller. Is a disadvantage that is easy to occur and difficult to obtain high strength and thermal dimension stability.

In addition, Japanese Patent Application Laid-Open No. 60-134015 proposes a method of suppressing spherical formation by passing through a pressure tube (usually 2 kgf / cm 2 or more), which is a high pressure when a thread passes through a high pressure gas sealed portion under the pressure tube. It destroys the sealing effect of gas and causes airflow defect in pressurized pipe, causing severe cross-disturbance, resulting in lower inter-fiber physical properties due to four-contact.

The present invention is to solve this problem and to practicalize the excellent properties of the nylon 46 polymer, and melt spinning the nylon 46 polymer to inhibit the spherical formation and growth as much as possible to perform three times stretching of 4.5 times or more continuously It is a method for producing a nylon 46 fiber having excellent physical properties of 9.0 g / d or more, 20% or more of cut elongation, 1.0% or less of dry heat shrinkage, 2.5% or less of non-aqueous shrinkage rate, or 95% or more of heat-resistant strong retention.

Hereinafter, the present invention will be described in detail, the nylon 46 polymer used in the present invention has a melting point of more than 92 mol% is composed of units of -NH- (CH ₂ ) ₄ -NH-CO (CH ₂ ) ₄ -CO- 280 ℃ The number average molecular weight measured by the gel permeation chromatography method by dissolving the nylon 46 unstretched yarn of the present invention in an olso-cresol and 2.2.2 trifluoro ethanol 1: 9 is above. It is preferable that the number average molecular weight is 8000 or more in order to give higher intensity | strength.

When the number average molecular weight of the nylon 46 unstretched yarn of the present invention exceeds 9000, the melt viscosity in a conventional screw-type melt extruder becomes excessively high, and due to the non-uniform heat dissipation of the molten polymer itself, In case of nylon 46 non-drawn yarn having a number average molecular weight of less than 6000, excessive stretching occurs during the three-stage stretching required in the present invention, resulting in a large amount of cutting of the filament, resulting in uneven workability and fiber properties. It becomes bad.

The spinning of high polymer polymers of nylon 6 and nylon 66 is carried out at 275 to 295 ° C, whereas for nylon 46 the spinning is carried out at higher temperatures. This is due to the higher content of amide groups in nylon 46 than in nylon 6 or nylon 66.

It is difficult to produce a fiber having excellent physical properties due to the rapid deterioration of nylon 46 due to the high temperature during spinning at the detention temperature of 310-330 ° C. proposed in Japanese Patent Laid-Open No. 59-88910.

In the present invention, the extruder type melt spinning machine supplies a chip of nylon 46 having a relative viscosity of 3.4 or more, but minimizes deterioration by low temperature supply by performing the temperature of the chip supply part of the extruder at 250 to 280 ° C, and the temperature of the detention (1). Is 290 ~ 310 ℃, and the molten polymer that passes through 100 ~ 300 plural holes is detained by a draw roller having a pulling speed of 400 ~ 800 meters per minute so that the spinning draft is 30 ~ 80, and the ambient temperature is 290 ~ 310. After passing the inside of the heating hood (2) maintained at 0.degree. C. within 0.2 seconds or more and within 0.8 seconds, a low temperature inert gas (3) such as nitrogen (N ₂ ) of 5 ° C or more and less than 15 ° C is introduced under the heating hood (2). To quench the exit thread.

In other words, by minimizing the residence time of the discharged molten polymer in the crystallization progression region (250 ℃-260 ℃) by improving the incomplete fiber structure due to the formation and growth of the spherical crystals due to the rapid crystallization rate to improve the elongation after the nylon It has been proposed as a method to improve the thermal dimensional stability at high temperatures, which is inherent in 46.

The present invention proposed as a method of minimizing the formation and growth of the spherical wells by minimizing the formation of the crystallization temperature region of nylon 46 in the temperature distribution from immediately below the detention (1) to before the take-up roller. A low temperature outflow tube 5 is installed between the part 4 and the low temperature outflow cylinder 5 of the mesh filter 7, a perforated plate 7 having 300 to 500 outflow holes, and a nonwoven fabric filter 8, in turn. The discharge yarns melt-extruded from the mold 1 pass through the heating hood 2 by stacking them so that the low-temperature inert gas 3 of 5 ° C. or more and less than 15 ° C., preferably 7 ° C. or more and less than 12 ° C. It is then quenched to inhibit the formation and growth of wells.

At this time, if the low-temperature inert gas (3) of less than 5 ℃ inflow quenching is too rapid quenching due to the structural difference between the inside of the filament and the surface layer (orientation and birefringence) causes the draw failure in later stretching, in particular stretched yarn Cracking of each filament surface results in deterioration of physical properties and poor quality of sand.

Even when the inert gas 3 of 15 ° C. or more is introduced, the discharge yarn in the molten state that has passed through the heating hood is allowed to pass through the atmosphere of the crystallization temperature region for a long time. It is impossible to obtain a fiber whose formation and growth are suppressed.

The cooling length by the inert gas 3 depends on the discharge speed, which means the residence time of the discharge yarn in the cooling length by the inert gas 3.

In the present invention, the take-off speed (discharge rate) of the discharge yarn is usually 400 to 900 m / min, and the cooling length by the inert gas 3 at this time is 50 to 100 mm.

If the cooling length is less than 50mm, the cooling residence time is too short to inhibit the formation and growth of the spheroid. If the cooling length is more than 100mm, the cooling residence time is too long, so that the structural difference between the inside of the filament and the surface layer (orientation and Birefringence) results in poor drawability during stretching, and in particular, due to cracking of the filament surface of each of the stretched yarns, deterioration of physical properties and poor quality.

According to the above method, nylon 46 fiber having excellent thermal dimensional stability of 9.0g / d or more, 20% or more of cut elongation, 1.0% or less of dry heat shrinkage, 2.5% or less of non-aqueous shrinkage, 2.5% or less of heat resistance, and 95% or more of heat resistance stability The nylon 46 fiber obtained by the present invention is excellent in high melting point and high heat resistance thermal dimensional stability, and is very useful as sewing thread, rubber reinforcement and other industrial materials.

[Examples and Comparative Examples]

In the extruder type melt spinning machine, melt 46 nylon chips with a relative viscosity of 3.7, varying the discharge rate and take-up speed from 150 g to 600 g per minute through spinnerets with 144 and 205 multiple spinnerets, respectively (400, 600, 900 per minute). Meter) After changing the temperature conditions of the low temperature inert gas as shown in the following Examples and Comparative Examples, a high magnification was carried out to obtain physical properties as shown in Table 1 and Table 2, wherein the inert gas was nitrogen gas.

The above result was measured by the following method.

(Strength, elongation at break)

Instron's 1123 Universal Testing Machine was used under conditions of a sample length of 25 cm and a tensile speed of 50 cm / min.

(Dry shrinkage rate, non-shrinkage rate, heat-resistant strength retention rate)

The dry heat shrinkage was measured under a load of 50 cm / min with a tensile length of Lo under a load of 0.1 g / d.

(Dry shrinkage rate, non-shrinkage rate, heat-resistant strength retention rate)

The dry heat shrinkage was set to Lo with the sample length under a load of 0.1 g / d and the load was removed, and then heat treated in a drying oven at 180 ° C. for 30 minutes. The non-aqueous shrinkage was also heat treated at 100 ° C. for 15 minutes in hot water in the same manner as the dry heat shrinkage. The length measured at the same load was made into L, and dry heat shrinkage rate and non-aqueous shrinkage rate were calculated | required by the following formula.

The heat-resistant strong maintenance rate is a strong percentage before and after heat treatment at 180 ° C. for 30 minutes in a drying oven.

(Chinese New Year Confirmation)

The surface and the cross section of the fiber were confirmed at a magnification of 10000 times using a model name JSM-T330A scanning electron microscope of JEOL, Japan.

Claims (3)

A method for producing a nylon 46 multifilament in which a nylon 46 chip is melt spun above a crystallization temperature and passed through a heating hood and a quenching portion at 290 ° C. to 310 ° C., and is drawn between 5 ° C. and 15 ° C. between the heating hood and the quenching part. A method for producing a nylon 46 multifilament, characterized by cooling with less than an inert gas. The method of claim 1, wherein the length of cooling the discharge yarn with an inert gas is 50 to 100 mm. The method of claim 1 wherein the inert gas is nitrogen gas.