KR20110073992A - Polyethyleneterephthalate fiber for air bag and fabric using the same - Google Patents

Abstract

PURPOSE: A polyethylene terephthalate fiber for an air bag and a fabric using the same are provided to prevent air bag burst. CONSTITUTION: A polyethylene terephthalate fiber for an air bag contains a force-deformation curve. The force-deformation curve increases under 4% in case that the initial stress is 1.0g/d at room temperature. The force-deformation curve increases under 12% in case that the intermediate stress is 4.5g/d. The force-deformation curve increases 3% or more until the fiber is cut from that the tensile strength is minimally 7.0g/d.

Description

Polyethylene terephthalate fiber for air bag and fabric using the same

The present invention relates to polyethylene terephthalate fibers for airbags and fabrics for airbags using the same, in particular by adjusting the force-strain curve of polyethylene terephthalate multifilament obtained by spinning a polyethylene terephthalate chip having an intrinsic viscosity of 0.8 to 1.3 Application to airbag fabrics provides airbag fabrics with improved bursting of edge bars to prevent bursting in airbag cushion deployment tests.

The requirements for airbags include a variety of items such as low breathability for smooth deployment during a crash, high energy absorption to prevent damage and rupture of the airbag itself, and foldability of the fabric itself to improve storage. 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 is increasing for cost reduction.

In order to use polyethylene terephthalate yarn in the air bag, it is necessary to solve the problem of popping up in the airbag cushion module deployment test.Efforts to improve the energy absorption performance of the polyethylene terephthalate air bag and to prevent the air bag edge bar from bursting during the air bag inflation Efforts are being made.

It is an object of the present invention to provide a polyethylene terephthalate fiber in which an airbag fabric using polyethylene terephthalate fiber is adjusted so that the force-strain curve of the fiber of the polyethylene terephthalate is not broken in the airbag cushion development test. .

In order to solve the above problems, according to a preferred embodiment of 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, at an initial temperature of 1.0 g / d at room temperature Force-strain curves that stretch less than 4% when subjected to strain, less than 12% when subjected to medium stress of 4.5 g / d, and stretch at least 3% until the fiber is cut from a tensile strength of at least 7.0 g / d. It has a cut elongation of 15% or more, a maximum thermal stress of 0.2 ~ 0.5g / d, terminal carboxyl group (CEG) content of 35mmol / kg or less, single yarn fineness of 5 denier or less to provide a polyethylene terephthalate multifilament do.

According to another suitable embodiment of the present invention, the total fineness of the polyethylene terephthalate multifilament is 150 to 1000 denier.

According to another suitable embodiment of the present invention, there is provided a fabric for an air bag woven using the polyethylene terephthalate multifilament.

According to another suitable embodiment of the present invention, the airbag fabric is prepared by coating at 15 to 60 g / m ² weight using a coating agent selected from the group consisting of silicone, polyurethane, acrylic, neoprene and chloroprene, (1 A coating fabric for an airbag having a tensile strength of 190 to 300 kgf, (2) tear strength of 25 to 40 kgf, and (3) air permeability of 0.5 CFM (Cubic Feet per Minute) is provided.

The present invention adjusts the force-strain curve of the polyethylene terephthalate fiber, the polyethylene terephthalate multifilament is stretched to less than 4% when subjected to the initial stress of 1.0 g / d at room temperature, subjected to medium-stress of 4.5 g / d Has a force-strain curve that stretches less than 12% when stretched and stretches by at least 3% from a tensile strength of at least 7.0 g / d until the fiber is cut, elongation at break of 15% and maximum thermal stress of 0.2-0.6 g By using polyethylene terephthalate fibers having a / d, terminal carboxyl group (CEG) content of 35 mmol / kg or less and single yarn fineness of 5 denier or less, a fabric for an air bag that does not burst in an air bag cushion development test can be prepared.

The present invention adjusts the force-strain curve of polyethylene terephthalate multifilament produced by spinning polyethylene terephthalate chip having an intrinsic viscosity of 0.8 to 1.3, and applies it to an airbag fabric so that the edge portion of the edge is not broken in the airbag cushion development test. To provide a fabric for the air bag improved the phenomenon.

According to a preferred embodiment of the present invention, in order to safely absorb the instantaneous impact energy of the exhaust gas generated by the explosive explosion inside the airbag, the airbag fabric obtained by spinning a polyethylene terephthalate chip having an intrinsic viscosity (IV) of 0.8 to 1.3. Polyethylene terephthalate multifilament is used. Polyester yarns having IVs with an inherent viscosity of less than 0.8 dl / g are not suitable because they do not provide yarns with sufficient toughness.

The resin for producing the synthetic fiber multifilament for the airbag of the present invention is polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene-1,2-bis (phenoxy) ethane-4, Copolymers comprising 4'-dicarboxylate, poly (1,4-cyclohexylene-dimethylene terephthalate) and at least one repeating unit of the polymer, for example polyethylene terephthalate / isophthalate copolyester , Polybutylene terephthalate / naphthalate copolyester, polybutylene terephthalate / decanedicarboxylate copolyester, and mixtures of two or more of the above polymers and copolymers. Among them, polyethylene terephthalate resin is particularly suitable for the present invention in terms of mechanical properties and fiber formation.

As for the terminal carboxyl group (CEG) content of the polyethylene terephthalate fiber of this invention, 35 mmol / kg or less is suitable. When the terminal carboxyl group (CEG) content of polyethylene terephthalate yarn exceeds 35mmol / kg, the hydrolysis performance of the yarn is lowered, making it difficult to maintain the performance of the airbag fabric under high temperature and high humidity conditions.

Fibers suitable for the polyethylene terephthalate multifilament for airbags of the present invention are preferred to elongate less than 4% when the force-strain curve is subjected to an initial stress of 1.0 g / d. Elongation of more than% may cause the fabric to be damaged early due to rapid deformation of the fabric.

In addition, in the present invention, when subjected to the medium-term stress of 4.5g / d, it is preferable to extend less than 12% of yarn, which extends more than 12% to the medium-term stress of 4.5g / d, the ventilation of the fabric is rapidly increased to exhaust gas It causes burns in the human body.

In addition, in the present invention, it is preferable that the fabric using polyethylene terephthalate yarn is stretched by 3% or more until the yarn is cut from a tensile strength of at least 7.0 g / d to have a tensile strength and tear strength suitable for use as an air bag. If the yarn is stretched less than 3% from the tensile strength of at least 7.0 g / d until the yarn is cut, there is a problem that the tensile strength and tear strength are insufficient when weaving a low weight fabric due to the lack of the maximum tensile load absorbing ability of the yarn.

The cutting elongation of the polyethylene terephthalate multifilament for airbags of the present invention is 15% or more, but if the cutting elongation is less than 15%, the airbag cushion is less suitable for absorbing energy when the airbag cushion is suddenly inflated. do.

It is preferable that the maximum thermal stress of the polyethylene terephthalate multifilament for airbags of this invention is 0.2-0.6 g / d. There is a problem that the yarn strength is insufficient in the production conditions of the yarn with a maximum thermal stress of less than 0.2 g / d, and the elongation of the yarn is low at the production conditions in which the maximum thermal stress is more than 0.6d / g.

It is preferable that the total fineness of the polyethylene terephthalate multifilament for airbags of this invention is 150-1000 denier, More preferably, it is 200-700 denier. If the total fineness is less than 150 denier yarns, the fabric for airbags is satisfactory in terms of storage, but it is not preferable because the bag lacks strength and may cause the bag to rupture during deployment and after a passenger collision. On the contrary, when the total fineness exceeds 1000 denier, sufficient strength is obtained as an air bag and satisfactory in terms of safety, but the fabric becomes thicker and the storage capacity becomes worse.

About single yarn fineness of the multifilament which comprises the fabric for airbags, it is suitable that it is 5 denier or less, Preferably it is 4.5 denier or less. Usually, the more the fiber of a single yarn fineness is used, the softer the woven fabric will be, the more excellent the foldability and the better the storage performance. Moreover, single yarn fineness becomes small, and covering property improves, As a result, the air permeability of a woven fabric can be suppressed. If the single yarn fineness exceeds 5 denier, it is not preferable because it does not exert sufficient function as an airbag fabric with deterioration of the foldability and storage property of the fabric and also deterioration of low breathability.

In the polyethylene terephthalate fiber produced by the manufacturing method of the present invention using an air jet or water jet loom, the residual oil of the fabric is preferably 0.1% by weight or less. It is desirable to weave into water jet rooms. Furthermore, after weaving, it is preferable to perform refining treatment and hot set treatment at 160 to 190 캜.

When weaving a woven fabric with polyethylene terephthalate fiber produced by the production method of the present invention, it is preferable to weave a plain weave having a symmetrical structure, but in order to obtain an attractive woven fabric, a yarn having a thinner linear density may be used. You can also weave in Panama.

Woven fabrics can be used by coating at 15 to 60 g / m ² weight using a coating agent selected from silicon, polyurethane, acrylic, neoprene and chloroprene to ensure low breathability suitable for airbag fabrics.

The physical property evaluation of an Example and a comparative example was measured or evaluated as follows.

1) Intrinsic viscosity (I.V.)

After dissolving 0.1 g of the sample in a reagent (90 ° C.) mixed with phenol and 1,1,2,2-tetrachloroethanol 6: 4 (weight ratio) for 90 minutes, transfer to a Ubbelohde viscometer and place it in a 30 ° C. thermostat. The solution is held for 10 minutes at, and the drop seconds of the solution are obtained by using a viscometer and an aspirator. The number of seconds of falling of the solvent can also be obtained by the following equations obtained from the above equations. The value was calculated.

R.V. = Number of drops of solvent / number of drops of solvent

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

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

2) Thermal stress measurement of yarn

Using KANEBO's thermal stress tester (model: KE-3LS), the yarn was looped to 10 cm, hooked on the upper and lower hooks, and subjected to an initial load of 0.05 g / den on the sample and heated at 2.2 ° C / sec. The stress generated in the sample is recorded in the chart and measured.

3) Measurement of terminal carboxyl group (CEG) content of yarn

The terminal carboxyl group content is analyzed by GRI (Geosynthetic Research Institute) Test Method "GG7" method and expressed in mmol / kg units.

4) How to measure the elongation of yarn

After leaving the yarn in a standard condition, that is, a constant temperature and humidity chamber at a temperature of 25 ° C. and a relative humidity of 65% for 24 hours, the sample is measured by a tensile tester using the ASTM 2256 method.

5) weaving and coating of fabrics

The filament yarns are woven into plain weave at 50 × 50 yarn densities per inch in both warp and weft directions. The dough is refined and shrunk in a jig at 95 ° C. in an aqueous bath and heat set at 185 ° C. for 2 minutes. And it was coated with a weight of 25g / m ² using a silicone-based coating agent.

6) tensile strength of fabric

Using Instron 4465 (manufactured by Instron, USA), the fabric is allowed to stand at 10 cm wide and 15 cm long after being left for 24 hours under standard conditions (20 ° C, 65 relative humidity) according to ASTM D 5034. Tensile strength of was measured.

7) Tear strength of fabric

Tear strength of the fabric after instron 4465 (manufactured by Instron, USA) for at least 24 hours under standard condition (20 ℃, 65 relative humidity) according to the tongue method according to ASDM D 2261 Was measured.

8) 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.

9) Deployment test of airbag cushion

After making the module with airbag fabric and leaving it at 85 ℃ for 4 hours, the development test was conducted within 3 minutes to observe the burst and evaluated PASS and FAIL.

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 following Examples.

Example 1

It is produced under the conditions of GR4 temperature 250 ℃, GR5 temperature 170 ℃, and relaxation ratio 9.2%. Plain as possible to prepare a dough for airbags.

Comparative Example 1

Polyethylene terephthalate yarn produced in the same conditions as in Example 1 except for the GR4 temperature 175 ℃, GR5 temperature 110 ℃, relaxation ratio 1.9% conditions and the characteristics shown in Table 1 below the same method as in Example 1 Dough for airbags was prepared.

Example 2

The dough prepared in Example 1 was refined and thermally contracted by passing through a 95 ° C. aqueous bath, and then heat-fixed at 185 ° C. for 2 minutes. And it is coated with a weight of 25g / m ² using a silicone coating agent.

Evaluation of the physical properties of the fabric thus prepared and the airbag cushion development test results are shown in Table 2 below.

Comparative Example 2

Evaluation of the physical properties of the fabric produced by treating the dough prepared in Comparative Example 1 in the same manner as in Example 2 and airbag cushion development test results are shown in Table 2 below.

TABLE 1

division standard cinnabar
Island
(den) burglar
(g / den) Shindo
(%) CEG
(mmol / kg) maximum
Thermal stress
(g / den) At 1.0 g / d
Elongation (%) At 4.5g / d
Elongation (%) % Elongation from 7.0 g / d to cutting Example 1 500d / 120f 4.2 9.0 22.6 25.1 0.29 0.9 9.7 5.1 Comparative Example 1 630d / 48f 13.2 8.1 12.3 25.3 0.53 0.8 5.4 4.0

TABLE 2

division The tensile strength
(Slope X weft, kgf) Phosphorus strength
(Slope X weft, kgf) Air permeability
(CFM) Airbag cushion
Deployment test Example 2 223 × 221 27.3 × 27.7 0.1 or less PASS Comparative Example 2 241 × 239 27.9 × 28.8 0.1 or less FAIL

Claims (4)

In the polyethylene terephthalate multifilament obtained by spinning a polyethylene terephthalate chip having an intrinsic viscosity of 0.8 to 1.3, Less than 4% when subjected to an initial stress of 1.0 g / d at room temperature, less than 12% when subjected to medium stress of 4.5 g / d, and when the fiber is cut from a tensile strength of at least 7.0 g / d. It has a force-strain curve that extends by 3% or more, and has an elongation at break of 15% or more, a maximum thermal stress of 0.2 to 0.5 g / d, a terminal carboxyl group (CEG) content of 35 mmol / kg or less, and a single yarn fineness of 5 denier or less. Polyethylene terephthalate multifilament characterized by the above-mentioned. The polyethylene terephthalate multifilament according to claim 1, wherein the total fineness of the polyethylene terephthalate multifilament is 150 to 1000 denier. An airbag fabric woven using the polyethylene terephthalate multifilament of claim 1. The airbag coating fabric of claim 3 is manufactured by coating at 15 to 60 g / m ² weight using a coating agent selected from the group consisting of silicone, polyurethane, acrylic, neoprene and chloroprene, and satisfying the following properties: (1) Tensile strength 190 to 300kgf, (2) Tear strength 25 to 40kgf, (3) Air permeability less than 0.5 CFM (Cubic Feet per Minute)