KR102454034B1 - Polyethyleneterephthalate fiber - Google Patents

Abstract

According to the present invention, since the fabric for an airbag mounted on a vehicle must exhibit stable performance even when exposed to various climatic environments, the tearing strength of the fabric exposed to a high-temperature environment must be sufficiently high to prevent the airbag from being torn during the airbag deployment process. There is provided a polyethylene terephthalate fiber for airbags in which the fabric for airbags exhibits high tearing strength even after being exposed to a high temperature environment of 80°C for 48 hours.

Description

Polyethylene terephthalate fiber for airbags

According to the present invention, since the fabric for an airbag mounted on a vehicle must exhibit stable performance even when exposed to various climatic environments, the tearing strength of the fabric exposed to a high temperature environment must be sufficiently high to reduce the damage of the airbag due to torn fabric during the airbag deployment process. can

Airbag fabrics require various characteristics, such as low air permeability for smooth deployment in the event of a collision, high energy absorption capacity to prevent damage and rupture of the airbag itself, and foldability of the fabric itself to improve storage properties. Nylon 66 material has been mainly used as a fiber suitable for the required characteristics of the airbag fabric, but in recent years, interest in fiber materials other than nylon 66 has been increasing due to economic feasibility such as cost reduction.

Many techniques have been disclosed for realizing an airbag having excellent foldability and a small storage volume without impairing high strength and low air permeability suitable as an airbag. For example, Japanese Unexamined Patent Application Publication No. Hei 1-41438 discloses that the above object is achieved by manufacturing an airbag fabric from yarns having a strength of 8.5 g/d or more and a single yarn fineness of 3 denier or less. are doing Although there is no mention of the difference between the coated fabric and the uncoated fabric in the above publication, the airbag fabric disclosed in the above publication is actually a so-called coated fabric in which an elastomer such as chloroprene rubber is applied to the surface of the fabric, and is an uncoated fabric. In the case of applying the technology to , the strength and storage properties were certainly satisfied, but the maintenance of low air permeability could not be sufficiently satisfied.

In addition, in Japanese Unexamined Patent Publication No. 4-201650, an airbag excellent in strength and foldability is used by using a polyamide multifilament composed of a plurality of single yarns having a different cross section with a single yarn fineness of 1.0 to 12 denier and a single yarn deformation degree of 1.5 to 7.0. A technique for obtaining a dragon fabric is disclosed. However, the airbag fabric manufacturing technology of the above publication also satisfies the required characteristics as an airbag fabric when applied to a coated fabric, but when applied to a non-exposure fabric, there remains a problem to be solved in terms of air permeability, especially in the air permeability in the sewing section. it was.

As a technique related to the uncoated fabric, there is a method described in Japanese Patent Application Laid-Open No. 7-252740. The publication discloses that by using a flat cross-section yarn having a flatness ratio of 1.5 or more, a fabric for an uncovered airbag excellent in low air permeability, foldability and storage property can be obtained. However, the fabric for an uncoated airbag disclosed in the above publication has an air permeability of 0.3 cc/cm 2 /sec or more under a low pressure (124 Pa), which cannot sufficiently satisfy the low air permeability required in recent years.

U.S. Patent No. 5,073,418 discloses a method of manufacturing a fabric with yarns of 500 denier or less and then calendering in order to show the effect of improving airtightness by lowering air permeability by calendering, but such a method is based on the tearing steel of the fabric. There is a problem with the level dropping.

European Patent Publication No. 416483 discloses a heat-shrinkable or heat-shrinkable uncoated fabric for manufacturing an airbag using a synthetic filament yarn having a substantially symmetrical structure and having a denier of 300 to 400 dtex. There is a problem in that the strength is sharply lowered, and the tear strength of the fabric is lowered.

European Patent Publication No. 436950 discloses a dense, dense, comprising treating a fabric made of a polyamide filament yarn having a hot air shrinkage of 6 to 15% at 160° C. and having a fabric structure at least approximately symmetrical in an aqueous bath at a temperature of 60 to 140° C. Although a method for manufacturing an industrial fabric having a single structure is disclosed, which does not require a coating treatment, in this method, the synthetic filament yarn undergoes heat shrinkage rapidly in a high-temperature aqueous bath, so that the present invention provides a variety of fabrics for airbags mounted on automobiles. Since stable performance must be exhibited even when exposed to climatic environments, the tear strength of the fabric exposed to the high temperature environment must be sufficiently high to reduce the damage to the bag due to tearing of the fabric during the airbag deployment process.

Korean Patent Publication No. 10-2012-0067767 Korean Patent Publication No. 10-1997-0021404

In order to solve the above problem, the present invention provides that the fabric for an airbag mounted on a vehicle must exhibit stable performance even when exposed to various climatic environments. It is possible to reduce the damage of airbags caused by airbags, and the fabric for airbags showed that the strength of the yarn was 6.5gf/den in the high temperature tensile test at 85℃. It is an object of the present invention to provide polyethylene terephthalate fibers for airbags suitable for high-temperature environments because fabrics made of yarns with greater than or equal to 19% elongation at cut exhibit higher tear strength even after aging at 80°C.

In order to achieve the above object, in the present invention, in a polyethylene terephthalate multifilament obtained by spinning a polyethylene terephthalate chip having an intrinsic viscosity of 0.8 to 1.3 dl/g, the yarn strength is 6.5 in a high temperature tensile test at 85 ° C. gf/den. Provided is a polyethylene terephthalate multifilament for airbags having a cut elongation of 19% or more.

According to another suitable embodiment of the present invention, the toughness of the polyethylene terephthalate yarn measured in the 85 ℃ high temperature tensile test is 32 × 10 ^-1 g / d or more is characterized.

According to another suitable embodiment of the present invention, the polyethylene terephthalate multifilament has a total fineness of 100 to 1000 denier of the polyethylene terephthalate multifilament, and the single yarn fineness of the multifilament is 2 to 10 denier.

According to another suitable embodiment of the present invention, the airbag fabric provides an airbag fabric, characterized in that the warp tear strength of the airbag fabric aged at 80° C. for 48 hours is 19 kgf or more.

Since the fabric for an airbag mounted on a vehicle of the present invention must exhibit stable performance even when exposed to various climatic environments, the tearing strength of the fabric exposed to a high temperature environment must be sufficiently high to reduce the damage of the airbag due to torn fabric during the airbag deployment process. can The fabric for airbag showed yarn strength of 6.5gf/den in the high temperature tensile test at 85℃. Fabrics made of yarns with greater than or equal to 19% elongation at cut exhibit higher tear strength even after aging at 80°C.

1 is a schematic diagram of a manufacturing process of a fiber for a polyethylene terephthalate airbag.

Hereinafter, the present invention will be described in more detail based on the drawings and examples.

Since the present invention can have various changes and can have various embodiments, specific embodiments are illustrated in the drawings and described in detail in the detailed description.

However, this is not intended to limit the present invention to specific embodiments, and should be understood to include all modifications, equivalents and substitutes included in the spirit and scope of the present invention. In describing the present invention, if it is determined that a detailed description of a related known technology may obscure the gist of the present invention, the detailed description thereof will be omitted.

The present invention adjusts the force-strain curve of polyethylene terephthalate multifilaments manufactured by spinning polyethylene terephthalate chips having an intrinsic viscosity of 0.8 to 1.3 dl/g and applies them to airbag fabrics so that they do not burst in the airbag cushion deployment test. Disclosed is a fabric for an airbag with improved part bursting.

The present invention relates to a polyethylene terephthalate obtained by spinning a polyethylene terephthalate chip having an intrinsic viscosity (IV) of 0.8 to 1.3 dl/g in order for the airbag fabric to safely absorb the instantaneous impact energy of the exhaust gas generated by the explosion of the gunpowder inside the airbag. Use multifilament. A polyester yarn having an intrinsic viscosity of less than 0.8 dl/g of a resin is not suitable because it does not provide a yarn with sufficient toughness. In addition, when the intrinsic viscosity (IV) exceeds 1.3 dl/g, the radioactivity is deteriorated.

The present invention will be described in detail with reference to the accompanying drawings.

In FIG. 1, the polyester chip having an intrinsic viscosity in the range of 0.80 to 1.30 dl/g is melted by setting the temperature condition of the extruder 1 low. At this time, the temperature of the molten polymer is set to 290 ~ 300 ℃, and a temperature is applied to keep the gear pump (2) warm. Also at this time, the set temperature of the heat preservation of the gear pump (2) is lowered and passed through the gear pump (2). Adjust the temperature of the polymer to be used to be 290 ~ 300℃ so that heat generation or thermal decomposition due to high temperature does not occur as much as possible, so that the physical properties of the polymer itself are not lost as much as possible. The diameter of the nozzle hole of the spinneret 3 is 0.3 to 0.6φ, and the ratio (L/D) of the hole length to the hole diameter of the spinneret 3 is 2 to 3 to maintain the spinning draft at a certain level and To provide high ductility. Conditions in the hood so that the length of the hood heater (4) is increased to 250 ~ 400mm and the temperature of the hood heater (4) is increased to 300 ~ 380℃ so that the spun fibers have an amorphous and non-oriented structure as much as possible. makes A large amount of air having a temperature of 10 to 17°C is supplied to the amorphous and non-oriented yarn formed in this way to the inlet (5) of the air supply pipe and discharged to the outlet (6) of the air exhaust pipe to enable rapid cooling. . At this time, the air supply amount was 50 ~ 90mmAq (aqua), and the exhaust amount was 70 ~ 100mmAq. After passing an appropriate amount of oiling to the solidified yarn in the amorphous and non-oriented state through the spinning emulsion supply device 7, a guide of a certain shape is applied before the godet roller (GR) 2 to apply multifilament to the surface of the roller on GR 2 . Make the area where the yarn contacts 1,000 ~ 3,000 (mm ² ) so that the primary stretching is good in GR 2 and GR 3, and then apply a guide before GR 3 to keep the spread of the yarn constant in GR 3 as well. Make the contact area of the multifilament yarn on the surface of the bed about 2,000 ~ 10,000 (mm ² ) so that the secondary stretching is performed well on GR 3 and GR 4, relax between godet rollers GR 4 and GR 5, and then roll the winding roller ( 13) is wound.

According to the present invention, the strength of the yarn in the high temperature tensile test at 85 ℃ 6.5gf / den. Fabrics made of yarns with greater than or equal to 19% elongation at cut exhibit higher tear strength even after aging at 80°C.

The polyethylene terephthalate yarn of the present invention is characterized in that the toughness measured in a high temperature tensile test at 85° C. is 32×10 ⁻¹ g/d or more.

In the 85 ℃ high temperature tensile test of the present invention, the strength of the yarn was 6.5 gf/den. The process used to form yarns with greater than or equal to 19% elongation at cut is to create conditions in the hood so that polyethylene terephthalate multifilaments can have as much amorphous and non-oriented structures as possible when passing through the hood heater (4). This includes the step of rapidly cooling the formed amorphous and non-oriented yarn in the cooling zone (5, 6) to maintain the amorphous and non-oriented state as much as possible to enable work with a high draw ratio.

A factor that greatly affects the multifilament of the present invention is the contact area of the filament yarns at GR where the initial primary stretching and secondary stretching occur. By adjusting the contact area, a desired force-strain curve of the multifilament of the present invention is obtained. The polyethylene terephthalate filaments that have passed through the cooling zones 5 and 6 have a constant area of contact with the surfaces of GR 2 and GR 3 which have a great influence on the initial primary and secondary stretching. The area where the multifilament yarns contact the godet roller surface where the initial primary stretching occurs is preferably ^2,000 to 4,000 mm ² desirable.

When the area where the multifilament yarns contact the godet roller surface where the initial primary drawing occurs is less than 2,000 mm ² and/or the area where the multifilament yarns contact the godet roller surface where the secondary drawing occurs is less than 7,000 mm ² , the multifilaments are uniform It is difficult to obtain the preferred multifilament of the present invention because heat transfer is difficult, and stretchability is lowered due to non-uniformity of the emulsion.

Conversely, when the area where the multifilament yarns contact the godet roller surface where the initial primary stretching occurs is greater than 4,000 mm ² and/or the area where the multifilament yarns contact the godet roller surface where the secondary high draw occurs is greater than 9,000 mm ² , Problems such as pin yarn induction and tar generation due to contact between multifilaments occur. Therefore, it has to be properly adjusted to have an appropriate contact area so that the amorphous non-oriented multifilament can achieve maximum elongation.

There are several factors that affect the contact area of the multifilament yarn with the godet roller surface. As a factor, the contact area increases in proportion to the number of turns (number of turns) of the filament wound on the extension GR. That is, the contact area can be adjusted by adjusting the number of windings.

Another important factor is to adjust the width of the yarn wound around the GR by applying a constant shape guide so that the spread of the yarn between the GRs can be kept constant.

In the present invention, it is preferable to use a guide shape of a fret shape. If the guide shape is a narrow V-groove, the thread width is reduced and the contact area is eventually reduced.

When the guides before the godet rollers 2 and 3 of the present invention are in the form of frets, the guide groove width is preferably 2.5 to 6.5 mm. More preferably, it is 3 to 5 mm, and most preferably, it is 4 mm. When the width of the fret-shaped guide groove is 6.5mm, there is a problem that pin yarn occurs due to the contact between the pillars. there is a problem.

Another factor that controls the contact area is the extension tension of the roller, the stretching temperature and the amount of emulsion.

In the present invention, the area where the multifilament yarn contacts the surface of GR 2, which has a great influence on the primary stretching by organically combining the above various factors, is 2,000 to 4,000 mm ² , and the secondary stretching of the Godet roller GR 3 The multifilaments of the present invention can be preferably obtained by adjusting the area where the multifilament yarns are in contact with the surface of 7,000 to 9,000mm ² .

Polyethylene terephthalate produced through this process showed a yarn strength of 6.5 gf/den in a high temperature tensile test at 85 °C. or more and the elongation at break is 19% or more. The polyethylene terephthalate yarn is characterized in that the toughness measured in a high temperature tensile test at 85° C. is 32×10 ⁻¹ g/d or more.

The total fineness of the polyethylene terephthalate multifilaments for airbags of the present invention is preferably 100 to 1000 denier, more preferably 200 to 700 denier. When a yarn having a total fineness of less than 100 denier is used, the fabric for an airbag is satisfactory in terms of storage properties, but it is not preferable because there is a risk of the bag rupturing during deployment and when a passenger collides after deployment due to insufficient strength. Conversely, if the total fineness exceeds 1000 denier, sufficient strength as an airbag can be obtained, which can be satisfied in terms of safety, but the fabric becomes thick and storage properties deteriorate.

Regarding the single yarn fineness of the multifilaments constituting the fabric for an airbag, it is preferably 5 denier or less, and more preferably 4.5 denier or less. In general, the more fibers with a smaller single yarn fineness are used, the more flexible the resulting fabric is, the better the foldability and the better the storage properties. In addition, the single yarn fineness is reduced and the covering property is improved, and as a result, the air permeability of the fabric can be suppressed. When the single yarn fineness exceeds 5 denier, it is not preferable because it does not exhibit a sufficient function as an airbag fabric with deterioration of foldability and storage properties of the fabric, and deterioration of low air permeability.

Hereinafter, the present invention will be described in detail with reference to examples, but the scope of the present invention is not limited or limited by the examples below.

Examples 1, 2, 3

Polyester chips with an intrinsic viscosity of 1.00 dl/g are extruded through a nozzle having a diameter of 0.4 mm, a length-to-diameter ratio (L/D) of 3, and a number of holes of 120, followed by cooling with air at 15°C and focusing. and the godet roller 2 temperature was 100°C, the godet roller 3 temperature was 125°C, and the spinning temperature, draw ratio, relaxation rate and godet roller 4 temperature were the conditions specified in Table 1, and the godet roller 2 (primary stretching). Point), the number of windings of the filament is 5, and the number of windings of the filament is 7 at Godet roller 3 (second drawing point), and the guide groove is flat before Godet rollers 2 and 3, and the width of the guide groove is It was 4 mm and the speed of the godet roller GR 4 was 2700 m/min, and 500 denier/120f was spun and stretched.

Comparative Example 1

The main conditions of Examples 1, 2, and 3 were the same, and the spinning temperature, draw ratio, relaxation rate and Godet roller 4 temperature were the conditions specified in Table 1, and the guide shape before Godet rollers 2 and 3 was a wide fret shape. The width of the groove is 6.5mm, and the number of windings of the filament is 5 times in Godet roller 2 and 7 times in Godet roller 3.

Comparative Example 2

The main conditions are the same as in Comparative Example 1, and the spinning temperature, draw ratio, relaxation rate, and Godet roller 4 temperature were the conditions specified in Table 1, and the guide shape before Godet rollers 2 and 3 was narrow (the width of the guide groove was 2.5). mm) and the number of windings is 6 times in Godet roller 2 and 8 times in Godet roller 3 of the filament.

How to measure

The physical properties of the yarns and airbag fabrics prepared in Examples 1 to 3 and Comparative Examples 1 to 2 were measured through the following test method.

1) Measurement of intrinsic viscosity (I.V.) of polyester chips

After dissolving 0.1 g of the sample in a reagent (90 ° C) mixed with phenol and 1,1,2,3-tetrachloroethanol in a weight ratio of 6:4 for 90 minutes to a concentration of 0.4 g/100 mL, Ubbelohde It was transferred to a viscometer and maintained in a thermostat at 30° C. for 10 minutes, and the number of seconds of falling of the solution was obtained using a viscometer and an aspirator. The number of seconds of falling of the solvent was obtained in the same way, and then R.V. and I.V. values were calculated by the following equations.

R.V. = Number of seconds of falling of the sample / Number of seconds of falling of the solvent

I.V. = 1/4××

In the above formula, C represents the concentration of the sample in solution (g/100 mL).

2) Measuring the elongation of the yarn

After allowing the yarn to stand for 24 hours in a constant temperature and humidity room with a standard condition, that is, a temperature of 25° C. and a relative humidity of 65% RH, the sample is measured through a tensile tester by the ASTM 2256 method.

3) Measurement of high temperature tensile strength of yarn

In measuring the maximum strength (gf/den.) and maximum elongation (%) of the yarn, the sample length is 250 mm, the tensile speed is 300 mm/min, and the initial load is set to 0.05 gf/den. The tensile test is carried out, but the measurement temperature is tested under high temperature conditions, not at room temperature, using a universal material tester (Instron, Model 5565) equipped with a 3119-600 Series environmental chamber. The sample was mounted, and the elongation test was performed when the chamber temperature reached 85°C. Tensile tests were performed 5 times per sample, and the average value was used.

At this time, when the high-temperature tensile test was performed with the fineness (denier) value measured under standard conditions (25℃, 65%RH), the strength (kgf) value of the yarn was divided by the tensile strength (gf/den.) value after the stagnant tensile test was calculated.

At this time, when the high-temperature tensile test was performed with the fineness (denier) value measured under standard conditions (25℃, 65%RH), the strength (kgf) value of the yarn was divided by the tensile strength (gf/den.) value after the stagnant tensile test was calculated.

4) Measurement of dry heat shrinkage of yarn

The shrinkage of the yarn is measured in a Testrite shrinkage tester under the condition of applying a load of 0.05 gf / denier for 2 minutes at 180 ° C.

5) Measurement of tear strength after high temperature aging at 80℃

The yarn produced in this way is woven in a plain weave with a warp density of 50 per inch and a weft density of 49 on a water jet loom, and then dried through a can dryer with a surface temperature of 180°C. The high-temperature tearing strength of the fabric for airbags prepared in this way was measured as follows. After aging the fabric for airbag at 80℃ for 48 hours and leaving it at 25℃ and 65%RH for 24 hours, the tear strength of the fabric was measured using a universal material tester (Instron, model 4465), and the tongue method according to ASDM D 2261 method. According to the measurement method of , the tear strength was calculated as the average value of the maximum 5 peaks issued when the specimen was torn while pulling at a constant test speed of 50 mm/min.

Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 radiation temperature 295℃ 295℃ 290℃ 305℃ 305℃ draw ratio 5.8 5.9 6.0 5.4 5.4 Relax ratio 9.0% 9.0% 8.5% 10.0% 11.0% heat treatment temperature
(No. 4 godet roller temperature) 245℃ 240℃ 235℃ 245℃ 250℃ Number of windings of filament at Godet roller 2 (1st draw point) 5 times 5 times 5 times 5 times 6 episodes Number of windings of filament at Godet roller 3 (second drawing point) Episode 7 Episode 7 Episode 7 Episode 7 Episode 8 Guide shape and width of guide groove before godet rollers 2 and 3 fret form,
4mm wide fret form,
4mm wide fret form,
4mm wide fret form,
6.5mm wide V Home
shape,
Width 2.5mm 85℃ measured yarn strength (gf/den.) 7.2 7.3 7.5 6.4 6.2 Measured 85℃ Yarn Elongation at Cut (%) 21.1 22.2 22.3 24.0 23.0 Toughness of yarn measured at 85℃ (×10 ^-1 g/d) 33.1 34.4 35.4 31.4 29.2 Warp tear strength (kgf) of fabric aged at 80℃ for 48 hours 19.7 20.1 20.4 18.5 18.1

As in Examples 1 to 3, the strength of the yarn was 6.5 gf/den in a high temperature tensile test at 85 ° C. Fabrics made of yarns with greater than or equal to 19% elongation at cut show higher tear strength even after aging at 80°C. There are advantages that can be

Unless otherwise defined in the present application, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs.

Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related art, and should not be interpreted in an ideal or excessively formal meaning unless explicitly defined in the present application. does not

1: Extruder
2: gear pump
3: spinneret
4: Hood heater
5: Air supply pipe inlet
6: Air exhaust pipe outlet
7: Spinning emulsion supply device
8: Stretch godet roller GR1
9: Stretch Godet Roller GR2
10: Stretch godet roller GR3
11: Stretch Godet Roller GR4
12: Stretch godet roller GR5
13: winding roller (winder)

Claims (5)

In the polyethylene terephthalate multifilament obtained by spinning a polyethylene terephthalate chip having an intrinsic viscosity of 0.8 to 1.3 dl/g,
In the 85℃ high temperature tensile test, the strength of the yarn was 6.5gf/den. or more, and the cut elongation is 19% or more,
Polyethylene terephthalate multifilament for airbag, characterized in that the toughness of the polyethylene terephthalate yarn measured in the 85°C high temperature tensile test is 32×10 ⁻¹ g/d or more.
delete The method of claim 1,
A polyethylene terephthalate multifilament for an airbag, characterized in that the total fineness of the polyethylene terephthalate multifilament is 100 to 1000 denier, and the single yarn fineness of the multifilament is 2 to 10 denier.
An airbag fabric, woven using the polyethylene terephthalate multifilament of claim 1 and aged at 80°C for 48 hours, has a warp tearing strength of 19kgf or more. delete

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