KR20050038367A - Polyhexamethylene adipamide fibers for uncoated airbag fabrics and process for preparing the same - Google Patents

Abstract

The present invention relates to a nylon 66 fiber suitable as a yarn for airbag fabric, and melt-extruded polyhexamethyleneadipamide chip having a relative viscosity of 2.5 or more through a spinneret to be cooled and solidified using a cooling gas under the spinneret. Winding the yarn at 1000mpm spinning speed, and a method comprising the step of stretching the wound yarn to a total draw ratio of 4.0 or more and multistage stretching and heat treatment, the value of dry heat shrinkage (195 ℃, 15 minutes) and non-shrinkage It relates to 200-1000 denier high-strength polyhexamethyleneadipamide fibers having a difference in value of (100 ° C, 30 minutes) of 1 or more.

In addition, the manufactured high-strength polyhexamethyleneadipamide industrial yarn of the present invention exhibits two-stage heat shrinkage characteristics, and the fabric using the same may be useful as an uncoated fabric for airbags having high tear strength and low breathability.

Description

Polyhexamethylene adipamide fibers for uncoated airbag fabrics and process for preparing the same}

The present invention relates to a nylon 66 fiber suitable as a yarn for airbag fabric, and melt-extruded polyhexamethyleneadipamide chip having a relative viscosity of 2.5 or more through a spinneret to be cooled and solidified using a cooling gas under the spinneret. Winding the yarn at 1000mpm spinning speed, and a method comprising the step of stretching the wound yarn to a total draw ratio of 4.0 or more and multistage stretching and heat treatment, the value of dry heat shrinkage (195 ℃, 15 minutes) and non-shrinkage It relates to 200-1000 denier high-strength polyhexamethyleneadipamide fibers having a difference in value of (100 ° C, 30 minutes) of 1 or more.

In addition, the manufactured high-strength polyhexamethyleneadipamide industrial yarn of the present invention exhibits two-stage heat shrinkage characteristics, and the fabric using the same may be useful as an uncoated fabric for airbags having high tear strength and low breathability.

In recent years, airbags are indispensable as devices for securing the safety of passengers in vehicles, and the installation rate on vehicles has gradually increased.

The requirements for airbags include a variety of things, such as low breathability for smooth deployment in the event of a crash, high strength to prevent damage and rupture of the bag itself, and furthermore flexibility for preventing passenger face scratches during deployment. In recent years, the airbag fabric itself has become an important requirement in terms of the foldability of the fabric itself, the improvement of the storage properties, and the cost reduction.

Regarding the shape of the air bag, it is roughly divided into a so-called coat fabric in which resin is applied to the surface of the fabric after weaving and a non-coat fabric using the fabric after weaving. It is advantageous.

Until now, many techniques for realizing an airbag excellent in foldability and small in storage volume without impairing the strength and low breathability suitable as an airbag have been disclosed. For example, Japanese Patent Laid-Open No. 1-41438 discloses strength 8.5. It is said that the above object is achieved by using an airbag fabric composed of yarns composed of fibers having a g / d or more and single yarn fineness of 3 deniers or less. Although not mentioned at all, it is substantially related to a so-called coated fabric in which an elastomer such as chloroprene is coated on the surface of the fabric. When the technique is applied to an uncoated fabric, it is certainly satisfied with respect to strength and storage property. However, it was not satisfactory enough in terms of maintaining low breathability.

In addition, Japanese Unexamined Patent Application Publication No. 4-201650 discloses an air bag having excellent strength and foldability by using a polyamide multifilament made of a plurality of single yarns having a single cross section having a single yarn fineness of 1.0 to 12 deniers and a single yarn strain of 1.5 to 7.0. However, a technique for obtaining a woven fabric is disclosed. However, the technique also satisfies the required characteristics as an airbag woven fabric only when applied to a coat woven fabric. Was left.

As a technique related to an uncoated fabric, there is a method described in Japanese Patent Application Laid-Open No. 7-252740. In the publication, by using a flatness of 1.5 or more and a flat cross-section yarn, a fabric for an uncoated air bag which is excellent in low air permeability, foldability, and storage property can be obtained. However, in this technique, the air permeability under low pressure (124 Pa) is 0.3 cc / cm 2 / sec or more, and it is not possible to sufficiently satisfy the air permeability lower than that required in recent years.

On the other hand, in order to cope with the US regulation FMVSS208 as amended in 2000, dualization of inflator is considered. Since this inflator is a two-stage deployment system, the gas output of the second stage is higher than that of the conventional inflator. For this reason, it is required to reduce the air permeability of the sewing part of the airbag and the fabric (hereinafter referred to as the sewing machine mesh misalignment) under the high pressure, which is less breathable than before.

In view of this, for example, Japanese Unexamined Patent Publication No. 2950954 discloses an uncoated fabric using a yarn having a total fineness of 300 to 400 dtex. However, the sewing mesh in the patent is not sufficiently small. Japanese Unexamined Patent Application Publication No. 8-2359 discloses an airbag fabric which defines the amount of residual oil deposition and the lubrication resistance of the fabric in a fabric having a cover cover of 900-1400. Also in the publication, it is hard to say that it is enough to satisfy the sewing part mesh shift.

 U. S. Patent No. 5,073, 418 proposes a method of manufacturing a fabric with less than 500 denier yarns and rendering it in order to lower the air permeability by calendering, thereby improving the airtightness. There is a problem of falling.

EP 416483 discloses heat-shrinkable or heat-shrinkable nonwoven fabrics for the manufacture of airbags having a substantially symmetrical structure and characterized by a synthetic filament yarn having a denier of 300 to 400 dtex, but such a method is known as a synthetic filament yarn. In the process, the strength is sharply lowered, there is a problem that the tear strength of the fabric is lowered.

EP 436950 includes treating a fabric made of polyamide filament yarn at a temperature of 60 ° C. to 140 ° C. in an aqueous bath, with a hot air shrinkage of 6 to 15% at 160 ° C. and at least nearly symmetrical fabric structure. , But a method for producing an industrial fabric having a dense structure, which does not require coating treatment, but such a method is a synthetic filament yarn heat shrinkage rapidly in a high temperature aqueous bath, the fabric quality is degraded, the fabric tear strength Has a problem of falling.

The present invention uses a high-strength polyhexamethyleneadipamide fiber in which the difference between the dry heat shrinkage (195 ° C., 15 minutes) and the non-shrinkage rate (100 ° C., 30 minutes) obtained by controlling the fine structure of the stretched yarn is one or more. By manufacturing the dough for the air bag, the dough can be continuously shrunk in the aqueous bath and hot air, the heat shrinkage of the fabric, which is a problem of the prior art proceeds rapidly, the quality of the fabric is degraded, the tear strength of the fabric is reduced Can be prevented. For this reason, fabrics for airbags made from the fibers of the present invention are excellent in tear strength, thin in thickness, and low in breathability.

It is also an object of the present invention to melt-extrude a polyhexamethyleneadipamide chip having a relative viscosity of 2.5 or more through a spinneret to cool and solidify it using a cooling gas under the spinneret, and to wind the yarn at a spinning speed of 200 to 1000 mpm. And a wound yarn having a total draw ratio of 4.0 or more and multistage stretching and heat treatment, the method comprising a dry heat shrinkage rate (195 ° C., 15 minutes) and a non-shrinkage rate (100 ° C., 30 minutes). The purpose is to provide a high strength polyhexamethyleneadipamide fiber of 200 to 1000 denier having a difference of at least one.

The present invention comprises the steps of (A) melt-extruding polyhexamethyleneadipamide having a hexamethyleneadipamide repeating unit of 85 mol% or more and having a relative viscosity in the range of 2.5 to 4.0 through a spinneret at a temperature of 270 to 320 ° C. ,

(B) cooling and solidifying using a cooling gas under the spinneret and drawing the undrawn yarn at a radial speed of 200 to 1000 mpm,

(C) to provide a high-strength polyhexamethyleneadipamide fiber that satisfies the following properties, prepared by the step of winding the stretched yarn through the multi-stage stretching and heat treatment at a total draw ratio of 4.0 times or more.

(1) the difference between the value of dry heat shrinkage (195 ° C., 15 minutes) and the non-shrinkage rate (100 ° C., 30 minutes) of 1% or more, (2) strength of 9.0 g / d or more, (3) elongation of 20% or more, (4) birefringence of 0.065 or less, (5) 200 to 1000 denier

In addition, the fineness of the polyhexamethyleneadipamide fiber is preferably 630 or 420 denier.

In addition, in the step (C), the one-stage stretching temperature is 20 to 50 ℃, it is preferable that the one-stage stretching ratio is 3.0 times or more.

In addition, in the step (C), the two-stage stretching temperature is 200 to 250 ℃, it is preferable that the two-stage stretching ratio is 2.0 times or less.

Moreover, it is preferable that the single yarn fineness of the said polyhexamethylene adipamide fiber is 3-7 deniers.

In addition, the winding speed of the drawn yarn in the step (C) is preferably 2000 to 3000mpm.

The present invention provides a fabric for an uncovered airbag that satisfies the following physical properties, woven using polyhexamethyleneadipamide fibers.

(1) tensile strength of 200 to 300 kg, (2) tear strength of 30 to 40 kg,

(3) Breathable 1.0 cm ³ / cm ² / sec or less

The polyhexamethyleneadipamide polymer used in the present invention contains at least 85 mole% of hexamethyleneadipamide repeating units, and preferably consists only of hexamethyleneadipamide units.

Alternatively, any polyamide homopolymer and copolymer can be used in place of the polyhexamethyleneadipamide. Such polyamides are mainly aliphatic. Poly (hexamethylene adipamide) (nylon 66); Poly (e-caproamide) (nylon 6); And widely used nylon polymers such as copolymers thereof. Nylon 66 is most preferred. Other nylon polymers that can be advantageously used are nylon 12, nylon 46, nylon 6 · 10 and nylon 6 · 12.

The polyhexamethyleneadipamide chip according to the present invention may be added in an amount such that the residual amount of copper metal in the final polymer is 20 to 50 ppm in order to improve thermal stability. Pyrolysis occurs due to poor thermal stability, and when it is more than 50 ppm, more than necessary copper metal acts as a foreign matter, which is a problem in spinning.

The polyhexamethyleneadipamide chip is fiberized according to the method of the present invention, and FIG. 1 schematically illustrates a manufacturing process according to one embodiment of this invention.

In step (A), the polyhexamethyleneadipamide chip is passed through a pack (1) and a nozzle (2) at a spinning temperature of preferably 270 to 310 ° C., preferably a spinning draft ratio of 20 to 200 (initial winding) Low-temperature melt spinning at a linear speed on the roller / linear speed at the nozzle) can prevent a decrease in the viscosity of the polymer due to thermal decomposition. If the spinning draft ratio is less than 20, the uniformity of the filament cross section worsens, and the drawing workability is significantly lowered. If it exceeds 200, the filament breakage occurs during spinning, making it difficult to produce a normal yarn.

In addition, in this invention, it is an important factor to adjust the filtration residence time in a pack to 3-30 second. If the filtration residence time in the pack is less than 3 seconds, the filtration effect of the foreign matter is insufficient, and if it is more than 30 seconds, pyrolysis is severe due to excessive pack pressure increase.

In addition, in the present invention, it is preferable to set the L / D (length / diameter) of the extruder screw to 20 to 50, which is difficult to uniformly melt when the L / D of the screw is less than 20, and to exceed 50 due to excessive shear stress. Molecular weight fall is severe and physical property is inferior.

In step (B), the melt release yarn 4 of step (A) is quenched by passing through the cooling zone (3).

In the cooling zone 3, an open quenching method, a circular closed quenching method, and a radial outflow quenching method may be applied depending on a method of blowing cooling air. Open quenching is preferred. Subsequently, the discharged yarn 4 solidified while passing through the cooling zone 3 can be oiled by the emulsion applying device 5 to 0.5 to 1.0%.

In step (C), the preferred spinning speed of the undrawn yarn is 200 to 1,000 m / min.

In step (D), the yarn having passed through the first stretching roller 6 is passed through a series of stretching rollers 7, 7, 8, 9 and 10 by spin draw, while the total draw ratio is at least 4.0 times, preferably The final stretched yarn 11 is obtained by stretching to 4.5 to 6.5.

The core of the technical configuration in the present invention is that the value of dry heat shrinkage (190 ° C., 15 minutes) is greater than the value of non-shrinkage rate (100 ° C., 30 minutes), and the difference is 1% or more. Shrinkage of such fibers is achieved by controlling the microstructure of the stretched yarn by a multistage stretching process. The multi-stage stretching process of the present invention consists of a primary stretching process proceeding at a high stretching ratio at a low stretching temperature and a secondary stretching process proceeding at a relatively low stretching ratio at a high temperature.

In the primary stretching step of the present invention, crystallization mainly by orientation proceeds. The crystallization by this orientation is a factor in determining the heat shrink in the fabric refining process. The preferred stretching temperature in the primary stretching process of the present invention is 20 to 50 ℃, the stretching ratio is 3.0 times or more, it is difficult to manage the stretching temperature is less than 20 ℃ without installing an additional cooling device in the stretching roller in the process. It is difficult and economically disadvantageous, and when the stretching temperature exceeds 50 ° C, crystallization by heat proceeds. Moreover, when the draw ratio is less than 3.0 times, sufficient orientation crystallization hardly occurs.

In the secondary stretching step of the present invention, crystallization by heat proceeds at a high temperature. The heat crystals at these high temperatures affect the heat shrinkage of the fabric in the hot air dryer, the drying process after refining. In the secondary stretching step of the present invention, the preferred stretching temperature is 200 to 250 ° C, and the draw ratio is 2.0 times or less. If the stretching temperature is less than 200 ° C, sufficient crystallization by heat does not proceed, and the stretching temperature exceeds 250 ° C. It causes damage to the yarn. In addition, when the draw ratio exceeds 2.0 times, the elongation of the yarn decreases drastically.

The key technical details of the present invention are designed to proceed heat shrinkage in multiple stages according to the temperature of the stretched yarn. The heat shrinkage characteristics of the airbag dough can be thermally contracted to net magnetic chuck in the refining and drying process, showing high quality and high utilization rate.

In the present invention, in the first stretching process, the stretching temperature is 20 to 50 ℃, the draw ratio is 3.0 times or more. In the preferred first drawing process

Stretched polyhexamethyleneadipamide fibers prepared according to the method of the present invention (1) the difference between the value of dry heat shrinkage (190 ° C, 15 minutes) and non-shrinkage (100 ° C, 30 minutes) is 1% or more, ( 2) strength of 9.0 g / d or more, (3) elongation of 20% or more, (4) birefringence of 0.065 or less, and (5) 200 to 1000 denier.

Stretched polyhexamethyleneadipamide fibers produced by the present invention utilize rapier or wortjet looms, so that 210 denier polyamide yarns typically have a yarn number of 27 to 30 / cm to achieve the required air permeability, In the case of 420 deniers, yarns of 16 to 22 / cm in both warp and weft yarns, and in the case of 630 deniers are woven in plain weave with 13 to 18 / cm yarns in both warp and weft yarns.

In the present invention, the woven fabric is preferably woven into a plain weave having a symmetrical structure. However, in order to obtain an attractive woven fabric, a yarn having a thinner linear density may be woven into a 2/2 Panama weave of a symmetrical structure.

Key technical details of the present invention are characterized by a process of heat shrinking the multi-stage in the refining and hot air dryer for airbag manufactured by the above-described method.

In the refining process of the present invention, the dough for airbags first passes through an aqueous bath having a temperature of 50 ° C. and sequentially passes three to six aqueous baths whose temperature rises in steps of 10 to 20 ° C. sequentially. At this time, the temperature of the final aqueous bath is 100 ℃. In the present invention, by sequentially increasing the heat shrink treatment temperature on the dough, it is possible to prevent the decrease in strength due to rapid heat shrink at a high temperature, which is a conventional problem.

Another feature of the present invention is to further heat shrink by passing the fabric subjected to heat shrink after the refining process through a hot air dryer. At this time, the temperature of the hot air dryer is 150 to 220 ℃, the hot air dryer is a structure in which the temperature is sequentially increased in accordance with the progress direction of the fabric. That is, the temperature of the fabric inlet of the hot air dryer is 150 ° C., but the temperature of the fabric outlet is 30 to 70 ° C. higher than the temperature of the inlet. By increasing the temperature of the hot air dryer of the present invention it is possible to prevent the strength decrease due to rapid heat shrink at a high temperature which is a conventional problem.

Another feature of the present invention is to adjust the heat shrinkage ratio in the refining process and the hot air dryer from 6: 4 to 9: 1. In the present invention, the heat shrinkage ratio of the fabric can be calculated from the length reduction of the entire fabric.

As described above, in the present invention, by controlling the non-shrinkage rate in the refining process of the fabric for airbags and the dry heat shrinkage rate in the hot air dryer at an appropriate ratio, it is possible to prevent dignity damage of the fabric due to the rapid shrinkage of the fabric and the strong utilization rate of the fabric Can improve.

Hereinafter, the present invention will be described in more detail based on the following examples. However, the following examples are not intended to limit the present invention, but are not limited thereto. Various physical property evaluations of the yarns and treatment cords prepared in Examples and Comparative Examples of the present invention were performed by the following methods.

(1) Relative viscosity (I.V.)

After dissolving 0.1 g of sample in sulfuric acid (90%) for 90 minutes to make the concentration 0.4g / 100ml, transfer to Ubbelohde viscometer, hold for 10 minutes in 30 ℃ thermostat, use viscometer and aspirator The number of seconds of the drop of the solution was calculated | required. The number of falling seconds of the solvent was also determined in the same manner, and then the R.V. value was calculated by the following equation.

(2) strength

Sample length of 250 mm, 300 mm / min after leaving at least 24 hours under standard conditions (20 ° C., 65% relative humidity) according to ASTM D 885, using Instron 5565 (manufactured by Instron, USA) The elongation was measured under the conditions of the tensile speed and 20 turns / m.

(3) non-shrinkage rate

The sample was left at 20 ° C. and 65% relative humidity for at least 24 hours, and then weighed to a weight of 0.1 g / d to measure the length (L 0), and treated in boiling water at 100 ° C. for 30 minutes under no tension. Next, taken out and left for 4 hours or more, the load was measured and the length (L) was measured, and the shrinkage ratio was calculated by the following equation.

(4) dry heat shrinkage

The sample was left at 20 ° C. and 65% relative humidity for at least 24 hours, and then weighed at a weight corresponding to 0.1 g / d to measure the length (L 0), followed by 10 minutes at 190 ° C. using a dry oven under no tension. After the treatment was taken out and left for 4 hours or more, the load (L) was measured, and the shrinkage ratio was calculated by the following equation.

(5) tensile strength of fabric

Using Instron 4465 (manufactured by Instron, USA), the fabric was allowed to stand for 10 hours or more in a standard condition (20 ° C., 65% relative humidity) according to ASTM D 5034. The tensile strength of the fabric was measured.

(6) tear strength of fabric

Tear steel of fabric using Instron 4465 (manufactured by Instron, USA) for at least 24 hours under standard conditions (20 ° C, 65% relative humidity) according to the tongue method under ASDM D 2261. The degree was measured.

(6) air permeability of fabric

Using a Frazier air permeability meter, the air permeability of the fabric was measured under 125 Pa pressure according to the ASDM 737 method.

(7) birefringence

It is measured by the following method using a polarizing microscope equipped with a Berek compensator.

Example 1

A polyhexamethyleneadipamide chip having a relative viscosity (RV) 3.5 containing 40 ppm each of copper metal was melt spun using an extruder at a spinning draft ratio of 40 at a temperature of 296 ° C. The filtration residence time in the pack was 15 seconds, the screw of the extruder used had an L / D of 35, and a static mixer with three units was installed in the polymer conduit of the pack to evenly mix the melt-spun polymer. The discharged yarn was then solidified through a 500 mm long cooling zone (20 ° C., cooling air blow with a wind speed of 0.5 m / sec) and then oiled with a spinning emulsion. This undrawn yarn was wound at a spinning speed of 470 m / min, gave 2% free draw, and then stretched in two stages. The first stage stretching was performed at 3.7 times at 30 ° C., the second stage stretching was performed at 1.5 times at 223 ° C., heat-set at 230 ° C., relaxed by 2%, and then wound to prepare a final drawn yarn of 630 d / 136 f denier.

The physical properties of the stretched yarn thus prepared are shown in Table 1 below.

[Examples 2 to 4 and Comparative Examples 1 to 4]

As shown in Table 1, a stretched yarn was prepared by performing experiments in the same manner as in Example 1 while varying the fineness, spinning temperature, and stretching conditions.

The physical properties of the drawn yarn thus obtained were evaluated and shown in Table 1 below.

TABLE 1

Example 5

The yarn prepared in Example 1 was plain weaved to a 41 × 41 fabric per inch with a rapier loom to prepare dough for airbags. The dough is first passed through an aqueous bath of 50 ° C., and successively passes through five aqueous baths in which the temperature is sequentially increased by 10 ° C. At this time, the temperature of the final aqueous bath is 100 ℃. After the refining process, further heat shrinkage is carried out by passing the fabric through a hot air dryer. At this time, the temperature of the hot air dryer is 150 to 220 ℃, the hot air dryer is sequentially increased in temperature according to the progress direction of the fabric.

Evaluation of the physical properties of the fabric thus prepared is shown in Table 2 below.

[Comparative Example 5]

The yarn prepared in Comparative Example 1 was flattened to a 41 × 41 fabric per inch with a rapier loom to prepare dough for airbags. The dough is first passed through an aqueous bath of 50 ° C., and successively passes through five aqueous baths in which the temperature is sequentially increased by 10 ° C. At this time, the temperature of the final aqueous bath is 100 ℃. After the refining process, further heat shrinkage is carried out by passing the fabric through a hot air dryer. At this time, the temperature of the hot air dryer is 150 to 220 ℃, the hot air dryer is sequentially increased in temperature according to the progress direction of the fabric.

Evaluation of the physical properties of the fabric thus prepared is shown in Table 2 below.

Comparative Example 6

The yarn prepared in Example 1 was plain weaved to a 41 × 41 fabric per inch with a rapier loom to prepare dough for airbags. The dough is rapidly thermally contracted by passing it through an aqueous bath at 95 ° C., and then dried in a 180 ° C. hot air dryer.

Evaluation of the physical properties of the fabric thus prepared is shown in Table 2 below.

Comparative Example 7

The yarn prepared in Example 1 was plain weaved to a 41 × 41 fabric per inch with a rapier loom to prepare dough for airbags. The dough was thermally contracted using a calendaring apparatus at 180 ° C. at a pressure of 483 kilopascals to prepare a fabric.

Evaluation of the physical properties of the fabric thus prepared is shown in Table 2 below.

Comparative Example 8

The yarn prepared in Comparative Example 1 was flattened to a 41 × 41 fabric per inch with a rapier loom to prepare dough for airbags. The dough is rapidly heat-shrunk by passing through a 95 ° C. aqueous bath, and then dried in a 180 ° C. hot air dryer.

Evaluation of the physical properties of the fabric thus prepared is shown in Table 2 below.

Comparative Example 9

The yarn prepared in Comparative Example 1 was flattened to a 41 × 41 fabric per inch with a rapier loom to prepare dough for airbags. The dough was thermally contracted using a calendaring apparatus at 180 ° C. at a pressure of 483 kilopascals to prepare a fabric.

Evaluation of the physical properties of the fabric thus prepared is shown in Table 2 below.

TABLE 2

division Yarn fine island Fabric Density (Bon / Inch) Tensile strength (㎏) Tear strength (㎏) Thickness (mm) Air permeability (cm 3 / cm 2 / sec) Weight (g / ㎡) Example 5 630d / 136f 41 × 41 271 × 263 33.5 × 28.3 0.37 0.4 234 Comparative Example 5 630d / 136f 41 × 41 241 × 223 23.5 × 20.3 0.39 1.4 239 Comparative Example 6 630d / 136f 41 × 41 211 × 201 19.5 × 18.3 0.40 0.9 237 Comparative Example 7 630d / 136f 41 × 41 205 × 198 18.5 × 18.1 0.3.8 1.4 234 Comparative Example 8 630d / 136f 41 × 41 191 × 182 17.5 × 16.3 0.41 1.9 236 Comparative Example 9 630d / 136f 41 × 41 185 × 171 16.5 × 15.3 0.40 1.7 234

The present invention uses a high-strength polyhexamethyleneadipamide fiber in which the difference between the dry heat shrinkage (195 ° C., 15 minutes) and the non-shrinkage rate (100 ° C., 30 minutes) obtained by controlling the fine structure of the stretched yarn is one or more. By manufacturing the dough for the air bag, the dough can be continuously shrunk in the aqueous bath and hot air, the heat shrinkage of the fabric, which is a problem of the prior art proceeds rapidly, the quality of the fabric is degraded, the tear strength of the fabric is reduced Can be prevented.

1 is a process schematic diagram illustrating the spinning process of the polyhexamethyleneadipamide fiber of the present invention.

Claims (8)

(A) melt extruding a polyhexamethyleneadipamide having a hexamethyleneadipamide repeating unit of 85 mol% or more and having a relative viscosity in the range of 2.5 to 4.0 through a spinneret at a temperature of 270 to 320 ° C; (B) cooling and solidifying using a cooling gas under the spinneret and drawing the undrawn yarn at a radial speed of 200 to 1000 mpm, (C) a high strength polyhexamethyleneadipamide fiber that satisfies the following properties, which is prepared by winding the stretched yarn through multistage stretching and heat treatment at a total draw ratio of 4.0 times or more. (1) the difference between the value of dry heat shrinkage (195 ° C., 15 minutes) and the non-shrinkage rate (100 ° C., 30 minutes) of 1% or more, (2) strength of 9.0 g / d or more, (3) elongation of 20% or more, (4) birefringence of 0.065 or less, (5) 200 to 1000 denier The method of claim 1, High strength polyhexamethyleneadipamide fiber, characterized in that the fineness of the polyhexamethyleneadipamide fiber is 630 denier. The method of claim 1, The high strength polyhexamethyleneadipamide fiber, wherein the polyhexamethyleneadipamide fiber has a fineness of 420 deniers. The method of claim 1, In the step (C), the one-stage stretching temperature is 20 to 50 ℃, the high-strength polyhexamethylene adipamide fiber, characterized in that the one-stage stretching ratio is 3.0 times or more. The method of claim 1, In the step (C), the two-stage stretching temperature is 200 to 250 ℃, the two-stage stretching ratio is polyhexamethyleneadipamide fiber, characterized in that less than 2.0 times. The method of claim 1, High-strength polyhexamethyleneadipamide fiber, characterized in that the single yarn fineness of the polyhexamethyleneadipamide fiber is 3 to 7 denier. The method of claim 1, Polyhexamethylene adipamide fiber, characterized in that the winding speed of the drawn yarn in the step (C) is 2000 to 3000mpm. A non-coated airbag fabric woven using the polyhexamethyleneadipamide fiber of claim 1, which satisfies the following physical properties: (1) tensile strength of 200 to 300kg, (2) tear strength of 30 to 40kg, (3) air permeability of 1.0 cm ³ / cm ² / sec or less