WO2019139406A1 - Polyethylene terephthalate yarn for airbag - Google Patents

Abstract

A fabric for an airbag equipped for an automobile needs to exert stable performance even when exposed to various climatic environments, and thus the tearing strength of a fabric exposed to a high-temperature environment must be sufficiently high to reduce the breakage of an airbag due to tearing of the fabric during the development of the airbag, so that the present invention provides a polyethylene terephthalate fiber for an airbag, allowing a fabric for an airbag to express high tearing strength even after the exposure to a high-temperature environment of 80°C for 48 hours.

Description

Polyethylene terephthalate yarn for airbags

This application claims the benefit of priority based on Korean Patent Application No. 10-2018-0003734 filed on August 11, 2018, and the entire contents of the Korean patent application are incorporated herein by reference.

Since the fabric for an airbag mounted on an automobile must exhibit a stable performance even when exposed to various climatic environments, the tear strength of the fabric exposed to a high temperature environment must be sufficiently high to reduce the damage of the airbag due to the tearing of the fabric during the airbag deployment .

The airbag fabric requires various characteristics such as low air permeability for smooth deployment at the time of collision, high energy absorbing ability for preventing damage breakage of the airbag itself, and foldability of the fabric itself for improving the storage capacity. Nylon 66 materials have been mainly used as the fibers suitable for the airbag fabrics, but in recent years, there has been a growing interest in fiber materials other than nylon 66 due to economical reasons such as cost reduction.

A large number of techniques for realizing an airbag that is excellent in collapsibility and small in storage capacity without damaging the strength and low air permeability suitable for the airbag have been disclosed. For example, Japanese Patent Application Laid-Open Publication No. 1-41438 discloses that the above-mentioned object is achieved by manufacturing a fabric for airbags made of fibers having a strength of 8.5 g / d or more and a monofilament fineness of 3 denier or less . Although no mention has been made on the difference between the coated fabric and the non-coated fabric in the above publication, the airbag fabric disclosed in the above publication is substantially a so-called coated fabric coated with an elastomer such as chloroprene rubber on the surface of the fabric, , The strength and retention properties are surely satisfied, but the point that maintenance of low air permeability can not be sufficiently satisfied.

Japanese Laid-Open Patent Publication No. 4-201650 discloses a polyamide multifilament comprising a plurality of single filaments each having a single-filament fineness of 1.0 to 12 denier and a single filament deformation of 1.5 to 7.0, A technique for obtaining a fabric for weaving is disclosed. However, the technology of manufacturing the airbag fabric of the above publication also satisfies the requirement as an airbag fabric when applied to a covering fabric. However, when applied to a non-bloomed fabric, the problem of air permeability, .

As a technique relating to a non-coated fabric, there is a method described in Japanese Patent Application Laid-Open No. 7-252740. It is disclosed in this publication that a fabric for a non-covered airbag having a low air permeability, a folding property, and a high retractability is obtained by using a flat cross-section yarn having a flatness of 1.5 or more. However, the uncoated airbag fabric of the above publication has an air permeability of 0.3 cc / cm < 2 > / sec or more at a low pressure (124 Pa), and has not satisfactorily satisfied the low air permeability required recently.

U.S. Patent No. 5,073,418 discloses a method of making a cloth with a yarn of 500 denier or less and then performing a color rendering in order to reduce the air permeability by knife rendering to improve airtightness. However, There is a problem that the price falls.

European Patent Publication No. 416483 discloses a heat shrinkable or heat shrinkable non-coated fabric for airbag production using a synthetic filament yarn having a substantially symmetrical structure with a denier of 300 to 400 dtex, So that the tear strength of the fabric is lowered.

European Patent Publication No. 436950 discloses a process for making a fabric made of a polyamide filament yarn having a heat shrinkage rate of 6 to 15% at 160 DEG C and a fabric structure of at least nearly symmetric at a temperature of 60 to 140 DEG C in an aqueous bath, A synthetic filament yarn is rapidly heated in an aqueous bath of a high temperature so that a product fabric of the fabric can be applied to various kinds of fabrics for airbags Since the fabric must exhibit stable performance even when exposed to the climatic environment, the tear strength of the fabric exposed to the high temperature environment must be sufficiently high to reduce the damage of the bag due to tearing of the fabric during the airbag deployment.

In order to solve the above problems, the airbag fabric to be mounted on a vehicle must exhibit stable performance even when exposed to various climatic environments. Therefore, the tear strength of the fabric exposed to the high temperature environment must be sufficiently high, It is possible to reduce the damage of the airbag caused by the airbag, and the strength of the yarn in the high temperature tensile test of 85 ° C is 6.5gf / den. Or more and a breaking elongation of 19% or more, the tear strength of the fabric is higher even after aging at 80 DEG C, and the object is to provide a polyethylene terephthalate fiber for airbags suitable for high temperature environments.

In order to achieve the above object, the present invention provides a polyethylene terephthalate multifilament obtained by spinning a polyethylene terephthalate chip having an intrinsic viscosity of 0.8 to 1.3 dl / g, wherein the yarn has a strength of 6.5 gf / dec. By weight and a elongation at break of 19% or more, based on the total weight of the poly (ethylene terephthalate) multifilament.

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

According to another preferred embodiment of the present invention, the polyethylene terephthalate multifilament is characterized in that the total fineness of the polyethylene terephthalate multifilament is 100 to 1000 denier and the fineness of the multifilament is 2 to 10.

According to another preferred embodiment of the present invention, the airbag fabric is characterized in that the airbag fabric aged at 80 DEG C for 48 hours has an intrinsic tear strength of 19 kgf or more.

Since the airbag fabric to be mounted on the automobile of the present invention must exhibit stable performance even when exposed to various climatic environments, the tear strength of the fabric exposed to the high temperature environment must be sufficiently high to reduce the breakage of the airbag due to tearing of the fabric during the airbag deployment process . The airbag fabric has a yarn strength of 6.5 gf / den in 85 ° C high temperature tensile test. And the elongation at break of 19% or more, the tear strength of the fabric is higher even after aging at 80 < 0 > C.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view showing a process for producing a fiber for a polyethylene terephthalate airbag.

Best Mode for Carrying Out the Invention The present invention will be described in more detail based on the drawings and examples.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail.

It should be understood, however, that the invention is not intended to be limited to the particular embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

The present invention relates to a polyethylene terephthalate multifilament prepared by spinning a polyethyleneterephthalate chip having an intrinsic viscosity of 0.8 to 1.3 dl / g by adjusting the force-deformation curve of the polyethylene terephthalate multifilament to a fabric for an airbag, The present invention provides a fabric for an airbag that is improved in the portion of the airbag.

The present invention relates to a polyethylene terephthalate (PET) obtained by spinning a polyethylene terephthalate chip having an intrinsic viscosity (IV) of 0.8 to 1.3 dl / g for safely absorbing instantaneous impact energy of an exhaust gas generated by explosive explosion of an airbag in an airbag fabric. Multifilaments are used. A polyester yarn having an intrinsic viscosity of less than 0.8 dl / g is not suitable because it does not provide a yarn having sufficient toughness. 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, polyester chips having intrinsic viscosity in the range of 0.80 to 1.30 dl / g are melted by setting the temperature condition of extruder 1 to be low. At this time, the temperature of the molten polymer is set to 290 to 300 DEG C and the temperature is applied for keeping the gear pump 2 warm. At this time, too, the set temperature of the keeping temperature of the gear pump 2 is lowered, The temperature of the polymer is adjusted to be 290 to 300 ° C so that the pyrolysis due to heat generation or high temperature is not caused to the maximum, so that the properties of the polymer itself are not lost as much as possible. The diameter of the nozzle hole of the spinneret 3 is set to 0.3 to 0.6 phi and the ratio of the hole length to the hole diameter (L / D) of the spinneret 3 is set to 2 to 3, Thereby imparting a high degree of extensibility. The length of the hood heater 4 is increased to 250 to 400 mm and the temperature of the hood heater 4 is raised to 300 to 380 ° C so that the spun fibers are subjected to the conditions in the hood . The amorphous and non-oriented yarns thus formed are supplied to the air supply pipe inlet 5 in a large amount of air having a temperature of 10 to 17 占 폚 and discharged to the air exhaust pipe outlet 6 so as to be rapidly quenched . At this time, the supply amount was made 50 to 90 mmAq (aqua) and the exhaust amount was made 70 to 100 mmAq. After the solidified yarn in the amorphous and non-oriented state is passed through an appropriate amount of oil ring through the emulsifying agent supply device 7, a certain type of guide is applied before the godet roller (GR) 2, GR 3 is applied to GR 3 and GR 3 in order to ensure that the width of the contact area is in the range of 1,000 ~ 3,000 (mm ² ) ( ² mm to 10,000 mm) of the surface of the multifilament yarn on the surface of the upper surface of the ^first and second rollers GR 1 and GR 4, and after the second drawing is performed on the GR 3 and GR 4, the rollers GR 4 and GR 5 are relaxed, 13).

According to the present invention, in the high temperature tensile test at 85 캜, the strength of the yarn is 6.5 gf / And the elongation at break of 19% or more, the tear strength of the fabric is higher even after aging at 80 < 0 > C.

The polyethylene terephthalate raw material of the present invention has a toughness of 32 x 10 < ^-1 > g / d or more as measured in a high temperature tensile test at 85 deg.

In the 85 DEG C high temperature tensile test of the present invention, the strength of the yarn is 6.5 gf / And the cutting elongation is 19% or more, the process used for forming the yarn in the hood is such that the polyethylene terephthalate multifilament has a structure that is as amorphous and non-oriented as possible when passing through a hood heater (4) And the thus formed amorphous and non-oriented yarns are rapidly cooled in the cooling zones 5 and 6 to maintain the amorphous and no-orientation states as much as possible to enable the operation at a high stretching ratio.

The factor that greatly affects the multifilament of the present invention is the contact width of the filament yarn in the GR in which the initial primary drawing and the secondary drawing are performed. By adjusting the contact width, a desired force-strain curve of the multifilament of the present invention is obtained. The polyethylene terephthalate filaments passing through the cooling zones (5, 6) have contact areas of a certain width with the surfaces of GR 2 and GR 3, which have a great influence on the initial primary and secondary stretching. It is preferable that the width of contact of the multifilament yarn with the surface of the godet roller where the initial primary stretching takes place is 2,000 to 4,000 mm ² and the width of the multifilament yarn contacting the surface of the godet roller where the secondary stretching takes place is 7,000 to 9,000 mm ² desirable.

In the case where the width of contact with the multifilament yarn on the surface of the godet roller where the initial primary elongation occurs is less than 2,000 mm ² and / or the width of contact with the multifilament yarn on the godet roller surface where the second elongation occurs is less than 7,000 mm ² , It is difficult to obtain a preferable multifilament of the present invention because heat transfer is difficult and the unevenness of the emulsion results in lowering in stretchability.

On the other hand, if the initial primary stretching takes place to the extent godet Saga multifilament contact with the roller surface than 4,000mm ^2, and / or the second stretching and the extent to which this occurs godet Saga multifilament contact with the roller surface than 9,000mm ^2, Problems such as pin yarn induction and tar occurrence due to contact between multifilament occur. Therefore, multifilaments with an amorphous orientation should be appropriately adjusted to achieve maximum extensibility with an appropriate contact area.

There are various factors that affect the extent to which the multifilament yarn contacts the surface of the godet roller. As a factor, the contact area increases in proportion to the number of turns (turn number) of the filaments wound on the drawn GR. That is, the contact width can be adjusted by adjusting the number of windings.

Another important factor is to adjust the warp wound on the GR by applying a constant shape guide to keep the yarn spread constant between the GRs.

In the present invention, it is preferable to use a prism-shaped guide. If the shape of the V-shaped guide is narrow, the width decreases and eventually the contact width decreases. If the guide is in the form of a pratt, the width increases and the contact width increases.

When the godet rollers 2 and 3 of the present invention are in the form of a prat, the guide groove width is preferably 2.5 to 6.5 mm. More preferably 3 to 5 mm, and most preferably 4 mm. In the case where the width of the prat-shaped guide groove is 6.5 mm, there is a problem that pin yarn is generated due to the contact between the pillars. When the width of the V-shaped guide groove is 2.5 mm, the godet roller is not uniformly heat- there is a problem.

Another factor controlling the contact width is the stretching tension of the roller, the stretching temperature, and the amount of emulsion.

In the present invention, the width of contact of the multifilament yarn to the surface of GR 2, which has a large influence on the primary drawing by organically binding the various factors, is 2,000 to 4,000 mm ² , and GR 3 The width of the surface of the multifilament yarn contacting the surface is adjusted to 7,000 to 9,000 mm ² , thereby obtaining the desired multifilament of the present invention.

The polyethylene terephthalate produced through such a process had a yarn strength of 6.5 gf / And the elongation at break is 19% or more. The polyethylene terephthalate raw material has a toughness of 32 x 10 < ^-1 > g / d or more as measured in a high temperature tensile test at 85 deg.

The total fineness of the polyethylene terephthalate multifilament for an airbag 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 deniers is used, the fabric for airbags is satisfactory in terms of retractability but is not preferable because of the lack of strength and the bag may rupture at the time of deployment and collision after deployment. On the contrary, if the total fineness exceeds 1000 denier, sufficient strength is obtained as an airbag, which can be satisfied from the viewpoint of safety, but the fabric becomes thick and the retention becomes poor.

The monofilament fineness of the multifilament constituting the fabric for an airbag is preferably 5 denier or less, and more preferably 4.5 denier or less. Generally, as the fiber having a small single filament fineness is used, the resultant fabric is flexible and excellent in folding property and storage stability. Further, 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. If the single yarn fineness exceeds 5 denier, it is not preferable because the folding property and the storage ability of the fabric are deteriorated, and the low air permeability is deteriorated and the sufficient function as the airbag fabric can not be exhibited.

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

Examples 1, 2, and 3

A polyester chip having an intrinsic viscosity of 1.00 dl / g was extruded through a nozzle having a diameter of 0.4 mm, a ratio of length to diameter (L / D) of 3 and a number of holes of 120, cooled with air at 15 ° C, And the temperature of the godet roller 2 was 100 캜 and the godet roller 3 temperature was 125 캜. The spinning temperature, the stretching ratio, the relaxation rate and the godet roller 4 temperature were the conditions specified in Table 1, and the godet roller 2 The number of windings of the filaments in the godet roller 3 (second elongation point) is 7, the shape of the guide before the godet rollers 2 and 3 is prat, and the width of the guide groove is 4 mm, and the speed of the godet roller GR 4 was set at 2700 m / min, and 500 denier / 120f was radiated and stretched.

Comparative Example 1

The main conditions are the same as those of Examples 1, 2 and 3, and the spinning temperature, the stretching ratio, the relaxation rate and the godet roller 4 temperature were set as shown in Table 1. The guides of the godet rollers 2 and 3 were wide, The width of the groove is 6.5 mm, the number of filaments wound on the godet roller 2 is 5, and that on the godet roller 3 is 7.

Comparative Example 2

The main conditions were the same as in Comparative Example 1, and the spinning temperature, the stretching ratio, the relaxation rate and the godet roller 4 temperature were set as shown in Table 1. The width of the guide grooves was 2.5 mm), the number of times of winding is 6 in the godet roller 2 of the filament, and 8 in the godet roller 3.

How to measure

The physical properties of the yarn and airbag fabric prepared through Examples 1 to 3 and Comparative Examples 1 and 2 were measured by the following test methods.

1) Intrinsic viscosity (I.V.) measurement of polyester chips

Phenol and 1,1,2,3-tetrachloroethanol in a weight ratio of 6: 4 was dissolved in a reagent (90 DEG C) for 90 minutes so as to have a concentration of 0.4 g / 100 mL, and the solution was dissolved in Ubbelohde The solution was transferred to a viscometer and maintained at 30 ° C in a thermostatic chamber for 10 minutes. The drop number of the solution was obtained by using a viscometer and an aspirator. The number of drops of the solvent was also determined by the same method, and then the RV value and the IV value were calculated by the following equation.

R.V. = Samples falling in water / solvent drops in seconds

I.V. = 1/4 x [(R.V.- 1) / C] + 3/4 (ln R.V./C)

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

2) Measuring the strength of yarn

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

3) High tensile strength of yarn

In measuring the maximum strength (gf / d.) And maximum elongation (%) of the yarn, the sample length is 250 mm, the tensile speed is 300 mm / min, the initial load is 0.05 gf / The test was carried out using a universal material testing machine (Instron, model 5565) equipped with an environmental chamber of 3119-600 Series for testing at a high temperature, not at room temperature. The sample was mounted, and the strength test was carried out when the chamber temperature reached 85 캜. Tensile tests were carried out five times per sample and average values were used.

The strength (gf / den.) After the tensile test was calculated by dividing the strength (kgf) of the yarn when subjected to high temperature tensile test at a fineness (denier) value measured under standard conditions (25 ° C., 65% RH).

4) Dry heat shrinkage measurement of yarn

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

5) Tensile strength measurement after 80 ℃ high temperature aging of fabric

The yarn thus produced is woven in a water jet loom in plain weave with an oblique density of 50 and an oblique density of 49, and then dried through a can dryer having a surface temperature of 180 ° C. The air bag fabric thus manufactured was subjected to hot tear strength test in the following manner. The fabric for airbags was aged at 80 DEG C for 48 hours and left for 24 hours under the conditions of 25 DEG C and 65% RH. The tear strength of the fabrics was measured using a universal material testing machine (Instron, Model 4465) , The tear strength was calculated as an average value of the maximum peaks of peaks issued when the test pieces were torn while constantly pulling at a test speed of 50 mm / min.

	Example 1	Example 2	Example 3	Comparative Example 1	Comparative Example 2
Radiation temperature	295 DEG C	295 DEG C	290 ° C	305 ℃	305 ℃
Stretching cost	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 (godet roller temperature 4)	245 ° C	240 ℃	235 ° C	245 ° C	250 ℃
The winding number of the filament at the godet roller 2 (first elongation point)	5 times	5 times	5 times	5 times	6 times
The number of take-up times of the filament at the godet roller 3 (second elongation point)	7 times	7 times	7 times	7 times	8 times
The shape of the guide before the godet rollers 2 and 3 and the width of the guide groove	Pratt shape, width 4mm	Pratt shape, width 4mm	Pratt shape, width 4mm	Pratt shape, width 6.5mm	V groove shape, width 2.5mm
85 ℃ Measured yarn strength (gf / den.)	7.2	7.3	7.5	6.4	6.2
85 ℃ Measuring elongation of yarn (%)	21.1	22.2	22.3	24.0	23.0
Toughness of yarn measured at 85 ° C (× 10 -1 g / d)	33.1	34.4	35.4	31.4	29.2
Tear strength (kgf) of the fabric aged at 80 ° C for 48 hours.	19.7	20.1	20.4	18.5	18.1

As in Examples 1 to 3, in the high temperature tensile test at 85 캜, the strength of the yarn was 6.5 gf / Or more and a breaking elongation of 19% or more, the tear strength of the fabric is higher than that of the fabric after aging at 80 ° C, so that when the airbag is exposed to a high temperature environment, the bag is prevented from being broken due to tearing There are advantages to be able to.

Unless specifically defined otherwise herein, 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 this invention belongs.

Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the contextual meaning of the related art and are to be interpreted as either ideal or overly formal in the sense of the present application Do not.

[Description of Symbols]

1: Extruder

2: Gear pump

3: spinning detention

4: Hood heater

5: Air inlet inlet

6: Exhaust air outlet

7: Radial emulsion feeder

8: Drawing godet roller GR1

9: Drawing godet roller GR2

10: Drawing godet roller GR3

11: Drawing godet roller GR4

12: Drawing godet roller GR5

13: Winding roller (winder)

Claims (5)

1. In a polyethyleneterephthalate multifilament obtained by spinning a polyethylene terephthalate chip having an intrinsic viscosity of 0.8 to 1.3 dl / g, the yarn has a strength of 6.5 gf / den in 85 < 0 > C high temperature tensile test. By weight and a elongation at break of 19% or more for polyethylene terephthalate multifilament for airbags.
2. The method according to claim 1,

   Wherein the polyethylene terephthalate yarn has a toughness of 32 x 10 < ^-1 > g / d or more as measured in the 85 DEG C high temperature tensile test.
3. The method according to claim 1,

   Wherein the polyethylene terephthalate multifilament has a total fineness of 100 to 1000 denier and a multifilament has a fineness of 2 to 10. 2. The polyethylene terephthalate multifilament for airbags according to claim 1,
4. A fabric for an air bag woven using the polyethylene terephthalate multifilament of claim 1.
5. 5. The method of claim 4,

   Wherein the airbag fabric has an airbag fabric aged for 48 hours at < RTI ID = 0.0 > 80 C < / RTI >

Images