KR101451192B1 - Polyethylene terephthalate filament for using air-bag - Google Patents

Abstract

The present invention relates to a process for producing an airbag fabric wherein the PET fiber produced by spinning a PET chip having an intrinsic viscosity of 0.8 to 1.3 dl / g elongates less than 4% when subjected to an initial stress of 1.0 g / d at room temperature, and having a strength-deformation curve that elongates by 8% or more when subjected to a stress of 10 g / d or more, and a cut elongation of 30% or more, characterized in that a PET filament ≪ / RTI >
Wherein the fiber has a terminal carboxyl group (CEG) content of 30 eq / Ton or less and a single filament fineness of 5 denier or less, and the PET fiber is used in either warp or weft yarns or both weft yarns and weft yarns.

Description

[0001] Polyethylene terephthalate filament for air bag [0002]

The present invention relates to a polyethylene terephthalate (PET) fiber for airbags, which improves the impact energy absorbing performance of instantaneous high pressure of PET fabric for airbags by adjusting the force-deformation curve of the fiber in a process of melt- How to do it.

Generally, an airbag refers to a device that protects the driver and passengers by explosion of the working gas device when a collision is detected by the sensor, and the bag is instantaneously inflated by the explosive gas. Description of the Related Art [0002] In recent years, an airbag has become indispensable as a device for ensuring the safety of a passenger on a vehicle, and the mounting rate of the airbag in a vehicle has been increasing rapidly.

The airbag fabric requires various characteristics such as low air permeability for smooth deployment in collision, high energy absorbing ability to prevent damage or rupture of the airbag itself, and foldability of the fabric itself to improve the storage capacity.

Nylon 66 is superior in impact resistance, but it is inferior in weather resistance and light resistance compared to polyester fiber, and nylon 66 is superior in nylon 66 because of economical efficiency such as cost reduction. Interest in non-66 textile materials is increasing.

Yarns used in typical airbag fabrics typically have a strength of from 8 to 10 g / d and an elongation at break of from 15 to 25%. When such yarns are used in curtain airbags, when high pressure gas is injected momentarily, The frequency of occurrence of defects is increased.

Polyethylene terephthalate (hereinafter referred to as PET) As a conventional method for producing high strength properties in the production of filament yarn, techniques have been developed in the direction of increasing the crystallinity on the microstructure of the fibers. As a method of increasing the crystallinity in the microstructure of a fiber, a method of producing a highly crystalline polyester resin in the polymerization step, a method of producing a general polyester resin having an intrinsic viscosity of 0.6 dl / g by a high speed radiator at a spinning speed of 7,000 m / A method of applying high temperature heat during the stretching process and a general polyester resin having an intrinsic viscosity of 0.6 dl / g are subjected to solid phase polymerization by a multistage temperature raising method to obtain a polyester having an intrinsic viscosity of 0.850 dl / g In order to overcome the mechanical thermal limitations caused by the use of the ester resin and PET alone, there are PET and a second component having excellent mechanical thermal properties, and a modification method by copolymerization and blending.

In this case, the crystallinity in the microstructure of the fiber is improved, but the fineness is generated when the interlacing technique, which is generally used, has a poor homeability. The fin yarns cause process problems in the case of flammability and heat treatment, and cause a decrease in the strength utilization ratio of yarns after they are made into air bag fabrics.

In addition, when a high-viscosity chip resulting from solid phase polymerization is used, or when a highly crystalline resin is used as a raw material in the polymerization step, there arises a problem that the spinning processability is lowered.

Therefore, in order to use the polyethylene terephthalate fiber in the air bag, the pin hole is minimized in the rod portion during the air bag cushion deployment, so that gas leakage from the rod portion is minimized, Improved performance and improved fabric tearing on the rods and the like are essential for fabricating airbag fabrics.

Korean Patent Publication No. 10-2012-0111418 (Oct. 10, 2012) Korean Registered Patent No. 10-1060246 (Aug. 23, 2011)

An object of the present invention is to provide a method for improving impact energy absorbing performance of an instantaneous high pressure of a PET fabric for an airbag in the production of a PET filament yarn by melt spinning a conventional PET chip.

The present invention relates to a PET fiber produced by spinning a polyethylene terephthalate (PET) chip having an intrinsic viscosity of 0.8 to 1.3 dl / g, which elongates less than 4% when subjected to an initial stress of 1.0 g / d at room temperature, and has a force-deformation curve that elongates by 8% or more when subjected to a stress of 10 g / d or more and a cut elongation of 30% or more.

According to a preferred embodiment of the present invention, the PET multifilament has a terminal carboxyl group (CEG) content of 30 eq / Ton or less.

According to another preferred embodiment of the present invention, the PET fiber has a monofilament fineness of 5 denier or less.

According to another preferred embodiment of the present invention, the PET fiber is used for either warp or weft yarns or for warp yarns and weft yarns.

The present invention aims to produce PET fibers for airbags capable of improving the impact energy absorbing performance of instantaneous high pressure of an airbag fabric, and the invention can be used to produce fabrics for airbags with improved impact energy absorbing performance .

The present invention is described in detail as follows.

The polyethylene terephthalate fiber for an airbag of the present invention is a polyethylene terephthalate fiber 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 inside the airbag, Polyethylene terephthalate multifilament obtained by spinning is used. A polyester chip having an intrinsic viscosity of less than 0.8 dl / g does not provide a yarn having sufficient toughness, and when the intrinsic viscosity is 1.3 dl / g or more, the polyester tends to deteriorate in stretchability.

As the resin for producing the multifilament for an airbag of the present invention, in addition to polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene-1,2-bis (phenoxy) '- dicarboxylate, poly (1,4-cyclohexylene-dimethylene terephthalate) and copolymers comprising at least one repeating unit of such a polymer, such as polyethylene terephthalate / isophthalate copolyester, Polybutylene terephthalate / naphthalate copolyester, polybutylene terephthalate / decanedicarboxylate copolyester, and mixtures of two or more of the foregoing polymers and copolymers. Of these, polyethylene terephthalate resins are particularly preferred in view of their mechanical properties and fiber formation.

Suitable fibers for the polyethylene terephthalate multifilament for the airbag of the present invention are preferably stretched less than 4% when the force-strain curve is subjected to an initial stress of 1.0 g / d. If the yarn has an initial stress of 1.0 g / d % Or more will cause the fabric to be damaged early due to rapid deformation of the fabric.

Also, in the present invention, it is preferable that the sagging is 8% or more when the stress is 3.0 g / d and the cut elongation is 30% or more. When the sagging is 3.0 g / d, the sagging is less than 8% And the instantaneous impact energy absorbing performance of the fabric made from this is lowered.

It is preferable that the yarn of the present invention is applied to the airbag fabric in which the resin is coated or the film is laminated, because the air permeability of the relevant portion increases when the elongation rate of the yarn is high and the exhaust gas leaks.

The polyethylene terephthalate fiber used in the polyethylene terephthalate fabric for an airbag of the present invention is characterized in that the content of the carboxyl end group (CEG (Carboxyl End Group)) is 30 eq / Ton or less.

If a polyethylene terephthalate yarn having a CEG content of more than 30 eq / Ton is used, the tensile strength and tear strength of the fabric are deteriorated under high humidity conditions, which is undesirable.

The monofilament fineness of the polyethylene terephthalate fiber for an airbag of the present invention is preferably 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. 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. If the single fiber fineness is more than 5 denier, the folding property and the storage ability of the fabric are deteriorated and the low air permeability is deteriorated, so that the fabric can not exhibit sufficient function as the airbag fabric.

The polyethylene terephthalate fiber produced by the production method of the present invention can be woven in lozenge loops, air jets or water jet looms in the form of a plain weave, or in the form of a piece woven (OPW (One Piece Woven)) in a jacquard loom. Further, after the weaving, it is preferable to perform refining treatment and heat set treatment at 160 to 190 占 폚.

According to another preferred embodiment of the present invention, the airbag fabric is coated with 20 to 80 g / m 2 by weight of a coating agent selected from the group consisting of silicone, polyurethane, acrylic, neoprene and chloroprene, or 15 to 60 g / In a laminating manner. The film to be used herein may be selected from the group consisting of a polyamide-based resin and a polyolefin-based resin in the form of a double layer or a polyester-based resin and a polyolefin-based resin in the form of a double layer.

The physical properties of Examples and Comparative Examples were measured or evaluated as follows.

1) Intrinsic viscosity (I.V.)

0.1 g of the sample was dissolved in a reagent (90 ° C) mixed with phenol and 1,1,2,2-tetrachloroethanol 6: 4 (weight ratio) for 90 minutes, transferred to a Ubbelohde viscometer, For 10 minutes, and use a viscometer and an aspirator to determine the number of drops of the solution. The number of drops of the solvent The RV value and I.V. Values were calculated.

R.V. = Sample falling water / solvent falling water water

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

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

2) How to measure 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) Air permeability of fabric

The air permeability of the fabric was measured under a pressure of 125 Pa in accordance with the ASDM D737 method using a Frazier air permeability meter

4) Deployment test of airbag cushion

The module was fabricated with the airbag fabric and allowed to stand at 85 ℃ for 4 hours and then developed for 3 minutes.

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

Example 1

Solid phase polymerized polyethylene terephthalate chips each containing 40 and 200 ppm of manganese and antimony metals and having a manganese / phosphorus ratio of 1.8 and a water content of 20 ppm and having an intrinsic viscosity (IV) shown in the following Table 1, respectively.
The prepared chips were melt-spun using an extruder at a beam temperature of 300 ° C and a B / L exhaust of 80 mm Aq. Thereafter, the discharged yarn was solidified by passing through a heating zone (atmosphere temperature: 350 ° C) having a length of 120 mm directly below the nozzle and a cooling zone having a length of 500 mm (blowing cooling air having a wind velocity of 0.5 m / sec at 20 ° C) Followed by oiling.
Thereafter, each unstretched yarn was stretched and wound up at a speed of 550 m / min for the godet roller 1, at a speed of 3,300 m / min for the godet roller 4, and at a stretching ratio of 6.0 to obtain the final drawn yarn A , B, C and D, respectively.

As shown in Table 2 below, yarn D was formed on the warp yarn and yarn A was formed on the weft yarn, and the warp yarn was woven in plain weave so that the fabric density was 57 x 57 per inch in both the oblique direction and the warp direction, In a water bath set stepwise from 50 ° C to 95 ° C and heat set at 190 ° C for 2 minutes. And coated with a silicone-based coating agent at a weight of 65 g / m 2.

The air permeability of the fabric thus fabricated was evaluated for its air permeability. The fabric was manufactured in the form of a curtain airbag and equipped with an inflator having a gas pressure of 406 kPa. The nearest region where the high pressure gas was injected, The damage to the nicknamed "calzone" site was observed and marked as PASS and FAIL in Table 2.

Example 2

The air permeability of the woven and coated fabric was evaluated in the same manner as in Example 1 except that the warp yarn was constituted by the yarn D as shown in Table 2 below and the weft yarn was constituted by the yarn B. The results are shown in Table 2, The test was carried out with an inflator with a gas pressure of 406 kPa. The nearest site where the high-pressure gas was injected, called the "calzone" area, was observed and the results are shown in Table 2 as PASS and FAIL.

Comparative Example 1

Table 2 shows the air permeability of the fabric woven and coated in the same manner as in Example 1 except that the warp yarn was constituted by the yarn D and the weft yarn was constituted by the yarn C as shown in Table 2 below. The test was carried out with an inflator with a gas pressure of 406 kPa. The nearest site where the high-pressure gas was injected, called the "calzone" area, was observed and the results are shown in Table 2 as PASS and FAIL.

division Yarn A Yarn B Yarn C Yarn D Seed 420d / 96f 420d / 96f 420d / 96f 420d / 96f Intrinsic viscosity (dl / g) 0.88 0.89 0.88 0.88 Single yarn fineness (den) 4.4 4.4 4.4 4.4 Elongation (%) at a stress of 1.0 g / d 1.0 1.4 0.8 0.9 Elongation (%) at a stress of 3.0 g / d 12.7 20.6 6.4 7.5 Breaking strength (g / d) 4.8 4.3 9.2 8.7 Elongation at break (%) 37.4 42.8 13.4 20.1 CEG content (eq / Ton) 27.8 28.1 27.4 27.6

division Example 1 Example 2 Comparative Example 1 slope Yarn D Yarn D Yarn D Weft Yarn A Yarn B Yarn C In the cushion development test, whether the "calzone" area is damaged PASS PASS FAIL Air permeability of fabric (cm3 / cm2 / s) 0.1 or less 0.1 or less 0.1 or less

As shown in Table 2, the polyethylene terephthalate fabric produced according to Example 1 and Example 2 of the present invention had excellent impact energy absorbing ability of the instantaneous high pressure of the yarn used in the weft, The degree of damage to the nearest site, the so-called calzone site, where high pressure gas is injected is improved.

Claims (4)

A polyethylene terephthalate fiber produced by spinning a polyethylene terephthalate chip having an intrinsic viscosity of 0.8 to 1.3 dl / g,
A polyethylene having an elongation of less than 4% when subjected to an initial stress of 1.0 g / d at room temperature and a force-deformation curve elongating more than 8% when subjected to a stress of 3.0 g / d, Terephthalate fiber.
The method according to claim 1,
Wherein the polyethylene terephthalate fiber has a terminal carboxyl group (CEG) content of 30 eq / Ton or less.
The method according to claim 1,
Wherein the polyethylene terephthalate fiber has a monofilament fineness of 5 denier or less.
A polyethylene terephthalate fabric for airbags, characterized in that the polyethylene terephthalate fiber of claim 1 is used either in warp or weft or in both warp and weft.