MX2012014677A

MX2012014677A - Fabric for airbag, using polyethylene terephthalate fiber with excellent heat resistance.

Info

Publication number: MX2012014677A
Application number: MX2012014677A
Authority: MX
Inventors: Il-Won Jung; Seung-Cheol Yang
Original assignee: Hyosung Corp
Priority date: 2010-06-24
Filing date: 2011-05-27
Publication date: 2013-02-11
Also published as: DE112011102093B4; WO2011162486A3; GB2495645A; CA2801482C; RO131566A2; US20130089725A1; CN102959147A; CA2801482A1; DE112011102093T5; JP2013528719A; RO131566B1; WO2011162486A2; CN102959147B

Abstract

The present invention relates to fabric for an airbag, using a polyethylene terephthalate fiber, and more specifically, to fabric for an airbag with improved heat resistance and instantaneous thermal deformation prepared by preparing a polyethylene terephthalate fiber for an airbag by controlling the strength and elongation of a polyethylene terephthalate fiber and using the same, to replace known fabric for an airbag using yarns made of Nylon 66. The fabric for an airbag of the present invention, comprising a polyethylene terephthalate fiber prepared by spinning polyethylene terephthalate chips having an intrinsic viscosity of 0.8-1.3 dl/g, has a heat resistance of 0.45-0.65 seconds at 450 and a heat resistance of 0.75-1.0 seconds at 350 .

Description

AIR BAG FABRIC, WHICH USES A FIBER OF POLYETHYLENE TERTHTALATE WITH EXCELLENT THERMAL RESISTANCE Field of the Invention The present invention relates to a fabric for an air bag using a polyethylene terephthalate fiber, and particularly, to a fabric for an air bag having improved thermal resistance and instantaneous thermal stress index, which is manufactured at using a polyethylene terephthalate fiber for an air bag, manufactured by controlling the strength and elongation of the polyethylene terephthalate fiber to replace a conventional fabric for an air bag using a wire formed of nylon 66.

Background of the Invention An airbag requires characteristics of low air permeability to break easily in a car accident, and absorb energy to prevent damage and deploy the same airbag. In addition, to store with greater ease, the characteristics in relation to the folding of the same fabric are required. As a convenient fiber having the characteristics described above, nylon 66 has generally been used. However, lately, to save costs, attention has been focused on fibers other than nylon 66.

As a fiber capable of being used for an air bag, polyethylene terephthalate can be used. However, when the polyethylene terephthalate is used as a yarn for an air bag, the seams are broken during the cushion module tests of the air bag. To solve this problem, it is important to use a polyethylene terephthalate yarn that does not degrade the energy absorption of an air bag. In addition, it is necessary to improve the flexibility of the fabric for an airbag by using a polyethylene terephthalate fiber that will be easily stored.

Brief Description of the Invention Technical problem The present invention relates to the supply of a fabric for an air bag using polyethylene terephthalate, which has an excellent energy absorption, which causes few external seam ruptures during the air bag's crash development tests, and that is stored more easily. Technical solution According to an exemplary embodiment of the present invention, there is provided a fabric for an air bag that includes a polyethylene terephthalate fiber manufactured by spinning a polyethylene terephthalate granule having an intrinsic viscosity of 0.8 to 1.3 dl / g. The fabric for an airbag has a thermal resistance of 0.45 to 0.65 seconds at 350 ° C, which is calculated by the following equation.

Equation 1 Thermal resistance (sec) of the fiber = ?? - T2 In equation 1, T, is the time in which a bar of steel heated to 350 ° C falls from 10 cm on the fabric and through it, and T2 is the time in which the same steel bar falls from the same height.

According to another exemplary embodiment of the present invention, a fabric for an air bag is provided which includes a polyethylene terephthalate fiber manufactured by spinning a polyethylene terephthalate granule having an intrinsic viscosity of 0.8 to 1.3 dl / g. The fabric for an airbag has a thermal resistance of 0.75 to 1.0 seconds at 450 ° C, which is calculated by the following equation, and an instantaneous thermal stress index of 1.0 to 5.0%.

Equation 2 Thermal Resistance (sec) of the fabric = T3 - T4 In equation 2, T3 is the time that a steel bar heated to 450 ° C falls from 10 cm on the fabric and through it, and T4 is the time when the same steel bar falls from the same height.

According to yet another exemplary embodiment of the present invention, the fabric for an airbag has a stiffness of 5.0 to 15.0 N.

According to another exemplary embodiment of the present invention, the polyethylene terephthalate fiber has a stiffness of 8.0 to 11.0 g / d, and an elongation of 15 to 30% at room temperature.

In accordance with yet another exemplary embodiment of the present invention, the polyethylene terephthalate fiber has an instantaneous thermal stress index of 1.0 to 5.0%, and a filament size of 4.5 deniers or less.

Advantageous Effects The present invention provides a polyethylene terephthalate fabric for an air bag, which overcomes the lack of flexibility, which is a disadvantage of a conventional fabric for an air bag, and has a better thermal resistance. As a consequence, a module of the air bag made using the fabric for an air bag can be stored more easily and unfolds infrequently, due to pressure and heat instantaneously applied by a gas that expands at high temperature during the Airbag deployment tests.

Detailed description of the invention The present invention provides a polyethylene terephthalate fabric for an air bag manufactured by manufacturing a polyethylene terephthalate fiber for an air bag by controlling the strength and elongation of the polyethylene terephthalate fiber, so as to obtain excellent thermal resistance and instantaneous thermal stress index. As a result, external seams break less frequently during the airbag cushion deployment tests, and the folding and storage of the fabric for an airbag is improved.

In the present invention, the fabric for an air bag uses a polyethylene terephthalate multifilament which is obtained by spinning a polyethylene terephthalate granule having an intrinsic viscosity (IV) of 0.8 to 1.3 dl / g to safely absorb the instantaneous impact energy of a consumed gas generated due to the explosion of gunpowder in the airbag. A polyester yarn having an intrinsic viscosity (IV) of less than 0.8 dl / g is not convenient, because the polyester yarn does not have enough strength to be used as an air bag.

A resin for producing a synthetic fiber multifilament for an air bag can be selected from the group consisting of polymers such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene-1,2-bis (phenoxy) ethane-4,4'-dicarboxylate, and poly (1,4-cyclohexylene-dimethylene); the copolymers include at least one of the polymers as a repeating unit, such as polyethylene terephthalate / isophthalate copolyester, terephthalate copolyester / polybutylene naphthalate, and terephthalate dicarboxylate copolymer / polybutylene decane; and a mixture of at least two of the polymers and copolymers. Among these, in the present invention, more preferably a polyethylene terephthalate resin is used in terms of mechanical properties and in the formation of a fiber.

The polyethylene terephthalate fiber for an air bag of the present invention can have a resistance of 8.0 to 11.0 g / d and an elongation of 15 to 30% at room temperature. When the strength of the polyethylene terephthalate fiber for an air bag of the present invention is less than 8.0 g / d, the polyethylene terephthalate fiber is not suitable for the present invention because of the low resistance to rupture and resistance to tearing fiber manufactured for an airbag.

In addition, when the elongation of the fiber is less than 15%, the absorption energy is decreased when a cushion of the airbag suddenly expands, and therefore, the cushion of the airbag deploys, which does not it is convenient. When a yarn is manufactured to have a fiber elongation of more than 30%, sufficient expression of the tension force is difficult due to the characteristics of a yarn manufacturing process.

The polyethylene terephthalate fiber for an air bag of the present invention may have a filament size of 4.5 denier or less, and preferably 3 denier or less. Generally, since a fiber having a smaller filament size is used, the obtained fabric becomes flexible, so that it reaches an excellent fold and a storage better. In addition, when the size of the filament is smaller, the coverage properties are improved at the same time. Consequently, the air permeability of the fabric can be inhibited. When the filament size is more than 4.5 deniers, the fabric has degraded folding and storage, and lowers air permeability, and therefore, the fabric can not serve properly as a fabric for an air pocket.

The polyethylene terephthalate fiber for an air bag of the present invention may have an instantaneous thermal stress index of 0.1 to 5.0%, and preferably 2.0 to 4.0% at 100 ° C. When the instantaneous thermal stress index of the fiber is less than 1.0%, the energy absorption applied when the airbag cushion expands due to a high temperature gas is degraded, and therefore, the cushion of the Air bag unfolds easily. In addition, when the instantaneous thermal stress index of the fiber is more than 5.0%, a fiber length is increased at high temperature, and therefore, the airbag cushion seams break when it expands due to a high temperature gas. Therefore, a gas that expands without control escapes.

In uncoated polyethylene terephthalate fabric whose density is 50 wefts or warps per inch after a washing and shrinking process, the stiffness may be from about 5.0 to 15.0 N, and preferably from 6.0 to 9.0 N when evaluated by the measurement of the circular fold. When the stiffness is more than 15.0 N, the fabric becomes stiff, and therefore, it is difficult to store in the manufacture of the air bag module and degrades in the unfolding operation of the air bag cushion.

In uncoated polyethylene terephthalate fabric whose density is 50 wefts or warps per inch after the washing and shrinking process, the thermal resistance measured using a bar heated to 350 ° C in a hot bar test may be 0.75 to 1.0 seconds When the thermal resistance measured at 350 ° C is less than 0.75 seconds, the thermal resistance of the fabric for an airbag is too low to withstand a high temperature gas in the deployment of the airbag cushion, and so Therefore, the external seams of the airbag break easily. When the thermal resistance measured at 350 ° C is more than 1.0 second, since a polyethylene terephthalate yarn having a larger filament size is necessarily used, the rigidity of the fiber is increased, and therefore, the Fabric for an airbag is difficult to store in the module.

In the uncoated polyethylene terephthalate fabric whose density is 50 wefts or warps per inch after a shrinkage and wash process, the thermal resistance measured using a steel bar heated to 450 ° C in a hot bar test may be from 0.45 to 0.65 seconds.

When the thermal resistance measured at 450 ° C is less than 0.45 seconds, the thermal resistance of the fiber for an airbag is too low to withstand a high temperature gas in the deployment of the airbag cushion, and so Therefore, the external seams of the airbag break easily. When the thermal resistance measured at 450 ° C is more than 0.65 seconds, since a polyethylene terephthalate yarn having a larger filament size is necessarily used, the rigidity of the fabric is increased, and therefore, the Fabric for an airbag is difficult to store in the module.

In the present invention, the fabric can be woven with the polyethylene terephthalate fiber as a flat fabric having a symmetrical structure. Or, to obtain the most favorable physical properties, the fabric can be woven as a 2/2 panama fabric having a symmetrical structure using a yarn having a smaller linear density.

The woven fabric can be coated with a coating agent selected from the coating agents based on silicon, polyurethane, acrylic, neoprene, and chloroprene at a weight of 15 to 60 g / m2 to ensure low air permeability, which is convenient for the fabric for an airbag.

The evaluation of the physical properties in the examples and comparative examples was done as follows: 1) Intrinsic Viscosity (I.V., for its acronym in English) 0. 1 g of a sample was dissolved in a reagent prepared by mixing the phenol and 1,1, 2,2-tetrachloroethanol in a weight ratio of 6: 4 (90 ° C) for 90 minutes. The resulting solution was transferred to an Ubbelohde viscometer and kept in a constant temperature oven of 30 ° C for 10 minutes, and a solution drop time was measured using a viscometer and a vacuum cleaner. A decay time of a solvent was also measured as described above, and then the R.V. and I.V. they were calculated by the following equations.

R.V. = Sample Fall Time / Solvent Fall Time I.V. = 1/4 x [(R.V.-1) / C] + 3 / 4x (In. R.V./C) In the above equation, C is the concentration (g / 100 ml) of the sample in the solution. 2) Measurement of the Instant Thermal Tension Index A bundle of filaments having a thickness of approximately 59 deniers was made by randomly selecting the multifilament yarn. The bundle of filaments was mounted on a TA instrument (model name: TMS Q-400) having a length of 10 mm, and therefore, a tension of 1.0 gf / den was applied thereon. 2 minutes after the application of tension, a test was started and the temperature increased rapidly from 30 to 100 ° C for 30 minutes. An instantaneous thermal stress index was obtained by dividing an increase in length of the sample when the temperature approached 100 ° C by an initial length of the sample, and is shown as a percentage. 3) Measurement of Fabric Rigidity The stiffness of a fabric was measured by measuring the circular fold according to the specification of ASTM D4032. Here, the stiffness was measured with respect to the warp and weft directions, and an average of the values obtained in the directions of the warp and weft is shown in units of Newtons (N). 4) Method of Measurement of the Thermal Resistance of the Fabric (test of hot bar at 350 ° C) A bar of cylindrical steel has a weight of 50 g and a diameter of 10 mm was heated to 350 ° C and then dropped vertically from 10 cm onto a cloth for an air bag. Here, the time in which the heated bar fell through the fabric was from You, and the time in which the bar fell without the fabric was from T2. The thermal resistance was measured by the following equation. Here, a non-folded fabric layer was used for an air bag.

Equation 1 Thermal Resistance (Seg) of the fabric = Tt - T2 5) Method of Measurement of the Thermal Resistance of the Fabric (hot bar test of 450 ° C) A cylindrical steel rod having a weight of 50 g and a diameter of 10 mm was heated to 450 ° C and then dropped vertically from 10 cm onto a cloth for an air bag.

Here, the time in which the heated bar fell through the fabric was T3, and the time in which the bar fell without the fabric was T. The thermal resistance was measured by the following equation. Here, a non-folded fabric layer was used for an air bag.

Equation 2] Thermal Resistance (Seg) of the Fabric = T3 - T4 6) Method to Measure the Stress Force and the Elongation of the Thread A sample of the yarn was left at a constant temperature and in a constant humidity chamber under standard conditions, ie, a temperature of 25 ° C and a relative humidity of 65% for 24 hours, and was tested by an ASTM 2256 method using a voltage tester. 7) Fabric and Fabric Coating A flat fabric was woven with a filament yarn to have a yarn density of 50 wefts or warps per inch in both weft and warp directions. A raw fabric was washed and contracted in the water baths, which were gradually set from 50 to 95 ° C using a continuous washing machine, and then treated at 200 ° C for 2 minutes by the thermomechanical treatment. Subsequently, the fabric was coated with a coating agent based on silicon at a weight of 25 g / m2. 8) Airbag Cushion Unfolding Test An air bag driver module (DAB) was made with a coated cloth for an air bag, and was subjected to a static test for several minutes after being left at 85 ° C for 4 hours . Here, one pressure of a powder inflator was 180 kPa, and when the tearing of the fiber, which forms a stippling and burning of the fabric, was not shown after the deployment test, it was evaluated as "Step". However, when any tearing of the fabric was shown, which forms a stippling in a seam and abrasion of the fabric, it was evaluated as "failure".

Mode of the Invention Next, the present invention will be described in detail with respect to the examples, but the scope of the present invention is not limited to the following examples and comparative examples.

Example 1 A raw fabric for an air bag was made with a polyethylene terephthalate yarn having the characteristics listed in table 1 by weaving in flat form using a rapier loom to have a fabric density of 50 wefts or warps per inch in both directions of the weft and the warp.

Example 2 A raw fabric for an air bag was made with a polyethylene terephthalate yarn having the characteristics listed in table 1 by the method as described in example 1.

Example 3 A raw fabric for an air bag was made with a polyethylene terephthalate yarn having the characteristics listed in table 1 by the method as described in example 1.

Comparative Example 1 A raw fabric for an air bag was made with a nylon 66 yarn having the characteristics listed in table 1 by a flat weave using a rapier loom to have a fabric density of 50 wefts or warps per inch in both directions of the weft and warp.

Comparative Example 2 A crude fiber for an air bag was made with a polyethylene terephthalate yarn having the characteristics listed in table 1 by the method as described in comparative example 1.

Comparative Example 3 A crude fiber for an air bag was made with a polyethylene terephthalate yarn having the characteristics listed in table 1 by the method as described in comparative example 1.

Example 4 The raw fabric manufactured in Example 1 was washed and contracted in gradually adjusted aqueous baths from 50 to 95 ° C using a continuous washing machine, and then treated at 200 ° C for 2 minutes by the thermomechanical treatment. In an uncoated state, the fabric was measured in stiffness, thermal resistance at 350 ° C and thermal resistance at 450 ° C, the results of which are shown in Table 2.

In addition, the manufactured fabric was coated with a silicon-based coating agent at a weight of 25g / m2 and heat-treated at 180 ° C for 2 minutes. A cushion of the air bag was made with the heat treated fabric, and subjected to a deployment test for the air bag cushion. The results of the test and storage in a module are shown in table 2.

Example 5 The crude fiber manufactured in example 2 was treated by the method described in example 4. The physical properties, result of a test of deployment of air bag cushion and storage in a module of the manufactured fabric, are shown in the table 2.

Example 6 The crude fiber manufactured in example 2 was treated by the method described in example 4. The physical properties, result of a test of deployment of air bag cushion and storage in a module of the manufactured fabric are shown in table 2 .

Comparative Example 4 The raw fabric manufactured in Comparative Example 1 was washed and contracted in gradually adjusted aqueous baths at 50 to 95 ° C using a continuous washing machine, and then treated at 200 ° C for 2 minutes by thermomechanical treatment. In an uncoated state, the fiber was measured in stiffness, thermal resistance at 350 ° C and thermal resistance at 450 ° C, the results of which are shown in Table 2.

In addition, the manufactured fabric was covered with a silicon-based coating agent at a weight of 25 g / m2 and heat-treated at 180 ° C for 2 minutes. A cushion of the air bag was made with the thermally treated fabric, and subjected to a deployment test for the cushion of the air bag. The results of the test and storage in a module are shown in table 2.

Comparative Example 5 The raw fabric made in comparative example 2 was treated by the method described in comparative example 3. The physical properties resulting from a test of deployment and storage in a module of the manufactured fabric are shown in table 2.

Comparative Example 6 The raw fabric made in comparative example 3 was treated by the method described in comparative example 3. The physical properties, result of a test of deployment and storage in one module of the manufactured fabric are shown in table 2. Table 1 Table 2 Although the invention has been shown and described in relation to certain exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the scope of the invention as defined by the appended claims.

Claims

1. A fabric for an air bag, comprising: a polyethylene terephthalate fiber manufactured by spinning a polyethylene terephthalate granule having an intrinsic viscosity of 0.8 to 1.3 dl / g, where the fabric for an airbag has a thermal resistance at 350 ° C from 0.75 to 1.0 seconds, which is calculated by the following equation: Equation 1 Thermal resistance (sec) of the fabric = Ti - T2 where is the time in which a steel bar heated to 350 ° C falls from 10 cm on the fabric through the cloth, and T2 is the time in which the same steel bar falls from the same height.

2. A fabric for an air bag, comprising: a polyethylene terephthalate fiber manufactured by spinning a polyethylene terephthalate granule having an intrinsic viscosity of 0.8 to 1.3 dl / g, where the fabric for an airbag has a thermal resistance at 450 ° C from 0.45 to 0.65 seconds, which is calculated by the following equation: Equation 1 Thermal Resistance (sec) of the fabric = T3 - T4 where T3 is the time that a steel bar heated to 450 ° C falls from 10 cm on the cloth through the fiber, and T4 is the time that the same steel bar falls from the same height.

3. The fabric for an air bag according to any of claims 1 and 2, wherein the polyethylene terephthalate fiber has an instantaneous thermal stress index of 1.0 to 5.0%

4. The fabric for an air bag according to any of claims 1 and 2, wherein the fabric for an air bag has a stiffness of 5.0 to 15.0 N.

5. The fabric for an air bag according to any of claims 1 and 2, wherein the polyethylene terephthalate fiber has a resistance of 8.0 to 11.0 g / d, and an elongation of 15 to 30% at room temperature.

6. The fabric for an air bag according to any of claims 1 and 2, wherein the polyethylene terephthalate fiber has a filament size of 4.5 denier or less.