KR20130020592A - How to make polyester yarn - Google Patents

Abstract

The present invention relates to a polyester yarn that can be used for fabrics for airbags, and in particular, a step of esterifying an aromatic dicarboxylic acid having 6 to 24 carbon atoms and an aliphatic dicarboxylic acid having 2 to 24 carbon atoms with glycol, the ester reaction Polycondensation reaction of the oligomer produced by the step, solid phase polymerization of the polymer produced by the polycondensation reaction, and melt spinning and stretching the polyester chip produced by the solid phase polymerization reaction It relates to a manufacturing method, yarn for airbags produced therefrom, and fabrics for airbags comprising the same.
Polyester yarns produced according to the present invention are not only low modulus, high strength but also have high shrinkage characteristics. In addition, the polyester yarn of the present invention significantly lowers the stiffness and secures excellent mechanical properties, thereby providing excellent storage properties, shape stability, and air barrier effect when used as an airbag fabric. In addition, the use of the polyester yarn of the present invention can significantly improve air permeability while preventing slipping and tearing of the fabric due to internal pressure during air bag deployment, thereby protecting the occupant from the impact of a car crash. Can be.

Description

How to make polyester yarn {PROCESS FOR PRODUCING POLYESTER FIBER}

The present invention relates to a method for producing a polyester yarn that can be used for fabrics for airbags, and more particularly, to a method for producing polyester yarns having excellent storage properties, flexibility, shape stability, and improved air barrier property during airbag deployment. It relates to yarn and fabric for airbags obtained from.

Generally, an air bag detects a collision impact applied to a vehicle at the time of a frontal collision at a speed of about 40 km / h or more at a speed of about 40 km / h by the impact sensor, And inflates the inflator to supply air to the inflator, thereby protecting the driver and the passenger. The structure of a typical air bag system is the same as that shown in Fig.

1, a general airbag system includes an inflator 121 that generates gas by ignition of a priming tube 122, and an airbag 124 that inflates and deploys toward the driver of the driver's seat by the generated gas An airbag module 100 mounted on the steering wheel 101, an impact sensor 130 for generating an impact signal in the event of an impact, and an electronic control module (not shown) for igniting the primer 122 of the inflator 121 And an electronic control module 110. When the vehicle collides head-on, the airbag system configured as described above senses an impact in the impact sensor 130 and transmits a signal to the electronic control module 110. At this time, the electronic control module 110 recognizing this ignites the primer 122 to burn the gas generating agent in the inflator 121. The gas generating agent thus combusted expands the air bag 124 through rapid gas generation. The inflated and deployed airbag 124 partially absorbs the impact load due to the collision while contacting the front surface of the driver and collides with the inflated airbag 124 as the driver's head and chest move forward due to inertia The gas of the airbag 124 is rapidly discharged to the exhaust hole formed in the airbag 124, so that the front surface of the driver is buffered. Therefore, by effectively buffering the impact force transmitted to the driver in the frontal collision, it is possible to reduce the secondary injury.

As described above, after the airbag used in the vehicle is manufactured in a predetermined form, the inflator 121 operates by being mounted on the handle of the vehicle, the side glass window or the side structure of the vehicle in a folded state to minimize the volume thereof, and maintaining the folded state. Allow the airbag to inflate and deploy.

Therefore, in order to effectively maintain the folding and packageability of the airbag when installing the vehicle, to prevent damage and rupture of the airbag itself, to exhibit excellent airbag cushion deployment performance, and to minimize the impact on passengers, the airbag fabric has excellent mechanical properties. In addition, foldability and flexibility to reduce the impact on passengers is very important. However, airbag fabrics that maintain excellent air blocking effect and flexibility at the same time for the safety of the passengers, sufficiently endure the impact of airbags and can be effectively mounted in a vehicle have not been proposed.

Conventionally, polyamide fibers such as nylon 66 have been used as a material for yarn for airbags. However, nylon 66 is excellent in impact resistance, but inferior in terms of moisture resistance, light resistance, shape stability and high raw material cost compared to polyester fiber.

On the other hand, Japanese Patent Application Laid-Open No. 04-214437 proposes the use of polyester fibers in which such defects are alleviated. However, in the case of manufacturing an air bag using such a conventional polyester yarn, due to the high stiffness and low flexibility peculiar to polyester, it is difficult to store it in a small volume in the vehicle, thereby reducing the folding ability and providing the passenger with the air bag cushion. There is considerable room for the impact to be applied. In addition, due to the characteristics of the polyester which is not decomposed by moisture or heat, there is a limit in maintaining sufficient mechanical properties and development performance under the severe conditions of high temperature and high humidity, so that it has not been applied commercially.

Therefore, it is possible to maintain a good shape stability and air blocking effect suitable for use as a fabric for airbags, and to develop a fiber yarn having excellent mechanical properties even under the harsh conditions of flexibility, storage properties, and high temperature and high humidity to reduce the impact on passengers. There is a need for research.

The present invention exhibits optimized flexibility and mechanical properties as yarn for airbags, making polyester yarns capable of providing airbag cushions that can further enhance foldability and deployment performance while minimizing passenger impact during deployment. To provide a method.

The present invention also aims to provide a polyester yarn produced according to the above method.

The present invention also provides a fabric for an air bag manufactured using the polyester yarn.

The present invention comprises the steps of esterifying an aromatic dicarboxylic acid having 6 to 24 carbon atoms and an aliphatic dicarboxylic acid having 2 to 24 carbon atoms with glycol; Polycondensation reaction of the oligomer produced by the ester reaction; Solid-phase polymerizing the polymer produced by the polycondensation reaction; And melt spinning and stretching the polyester chip produced by the solid state polymerization reaction, wherein the aromatic dicarboxylic acid, aliphatic dicarboxylic acid, and glycol have a molar ratio of the total amount of dicarboxylic acid and glycol. Provided is a 1: 1 to 1: 1.5, a molar ratio of aromatic dicarboxylic acid and aliphatic dicarboxylic acid is 1: 0.01 to 1: 0.15 to provide a method for producing a polyester yarn to react.

The present invention also provides a polyester yarn produced by the above method.

The present invention also provides a fabric for an air bag manufactured using the polyester yarn.

Hereinafter, a method of manufacturing a polyester yarn and an airbag yarn and a fabric prepared therefrom according to a specific embodiment of the present invention will be described in detail. It will be apparent to those skilled in the art, however, that this is not intended to limit the scope of the invention, which is set forth as an example of the invention, and that various modifications may be made to the embodiments within the scope of the invention.

In addition, throughout this specification, "comprising" or "containing ", unless specifically stated, refers to including any and all components (or components) Can not be interpreted as excluding.

The fabric for the polyester airbag is melt spun to a polymer including polyethylene terephthalate (hereinafter referred to as "PET") to produce an unstretched yarn, which is stretched to obtain a stretched yarn (ie, yarn), and then through this process. It can be produced by weaving the obtained polyester yarn. Therefore, the properties of the polyester yarn is directly or indirectly reflected in the physical properties of the fabric for the polyester airbag.

In particular, in order to apply polyester as an airbag yarn instead of polyamide fibers such as conventional nylon 66, the high temperature and high humidity stiffness resulting from the low fusion heat capacity and the low melting heat capacity due to the high modulus and stiffness of the polyester yarn Under the conditions, it should be possible to overcome the deterioration of physical properties and consequently the deterioration of development performance.

Polyester has a high stiffness structure compared to nylon in the molecular structure has a high modulus characteristics. For this reason, when used as a fabric for airbags to be mounted on a car, the packing (packing) is significantly reduced. In addition, the carboxyl end groups (hereinafter referred to as "CEG") in the polyester molecular chain attack the ester bond under high temperature and high humidity conditions to cause molecular chain breakage, thereby deteriorating physical properties after aging. Becomes

Accordingly, the present invention is produced by using a specific aromatic dicarboxylic acid and aliphatic dicarboxylic acid together in the optimum composition range in the reaction of dicarboxylic acid and glycol which is a dihydric alcohol in the production process of the polyester yarn. It has excellent toughness, tear strength and edge comb resistance, and maintains high air barrier performance while significantly lowering the stiffness of polyester yarn. Applicable

 In particular, the experimental results of the present inventors, by applying a polyester yarn prepared through the optimized composition range and process conditions, such as airbag fabric, exhibits improved folding properties, shape stability, and air barrier effect to produce a car It has been found that excellent mechanical properties, air leakage prevention, airtightness, and the like can be maintained even under severe conditions of packing and high temperature and high humidity in mounting and the like.

According to one embodiment of the present invention, a method for producing a polyester yarn is provided. Such a method for producing a polyester yarn comprises the steps of ester-reacting an aromatic dicarboxylic acid having 6 to 24 carbon atoms and an aliphatic dicarboxylic acid having 2 to 24 carbon atoms with glycol; Polycondensation reaction of the oligomer produced by the ester reaction; Solid-phase polymerizing the polymer produced by the polycondensation reaction; And melt spinning and stretching the polyester chip produced by the solid state polymerization reaction. In addition, in the ester reaction step, the aromatic dicarboxylic acid, aliphatic dicarboxylic acid, and glycol are such that the molar ratio of total dicarboxylic acid and glycol is 1: 1 to 1: 1.5, and aromatic dicarboxylic acid and aliphatic The molar ratio of the dicarboxylic acid can be 1: 0.01 to 1: 0.15 so as to react.

Hereinafter, a method of manufacturing such a polyester yarn will be described in detail for each step.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other features and advantages of the present invention will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: FIG.

2 is a process diagram schematically showing a polyester yarn manufacturing process including the melt spinning and stretching step according to an embodiment of the present invention. As shown in Figure 2, the production method of the polyester yarn for the airbag of the present invention melts the polyester polymer prepared in the manner described above, cooling the molten polymer spun through the detention with quenching-air The emulsion is applied to the undrawn yarn using an emulsion roll (220, or oil-jet), and the oil applied to the undrawn yarn is subjected to a constant air pressure using a pre-interlacer (230). It can be uniformly dispersed on the surface. Then, after the stretching process through the multi-stretching device (241 ~ 246), and finally by the second pressure (2 ^nd Interlacer, 250) in the constant pressure (intermingle) to the yarn (intermingle) winding the winding machine 260 Can be produced to produce yarn.

On the other hand, the production method of the present invention, in order to manufacture a high-strength low modulus high-shrink polyester yarn that can be effectively used for fabric for airbags, it can be used to prepare a high viscosity polyester polymer. In particular, the polyester polymer can be produced by esterifying a glycol with an aromatic dicarboxylic acid having 6 to 24 carbon atoms and an aliphatic dicarboxylic acid having 2 to 24 carbon atoms. The polyester polymer thus prepared has a low carboxyl end group (CEG) content with high intrinsic viscosity, so that excellent mechanical properties and air leakage prevention, airtightness, etc., even after aging under severe conditions of high temperature and high humidity when processed into a polyester yarn It can be effectively applied to fabrics for airbags.

In particular, the polyester polymer in the production method of the present invention comprises the steps of ester-reacting the aromatic dicarboxylic acid having 6 to 24 carbon atoms and the aliphatic dicarboxylic acid having 2 to 24 carbon atoms with glycol; Polycondensation reaction of the oligomer produced by the ester reaction; Solid-phase polymerizing the polymer produced by the polycondensation reaction; And melt spinning and stretching the polyester chip produced by the solid state polymerization reaction.

The esterification reaction of the present invention is carried out using an aromatic dicarboxylic acid having 6 to 24 carbon atoms and an aliphatic dicarboxylic acid having 2 to 24 carbon atoms as a dicarboxylic acid component. At this time, the aromatic dicarboxylic acid having 6 to 24 carbon atoms include terephthalic acid (p-phthalic acid), isophthalic acid (m-phthalic acid), phthalic acid (o-phthalic acid), diphenyl ether dicarboxylic acid, bi And at least one selected from the group consisting of phenyldicarboxylic acid, 1,4-naphthalene dicarboxylic acid, 1,5-naphthalene dicarboxylic acid and ester-forming derivatives thereof. Among them, it is preferable to use terephthalic acid in consideration of economical properties and physical properties of the finished product.

In addition, examples of the aliphatic dicarboxylic acid having 2 to 24 carbon atoms which perform ester reaction with the glycol component include oxalic acid, malonic acid, succinic acid, and glutaric acid. Glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, and ester-forming derivatives thereof And at least one selected from the group consisting of. Among them, adipic acid can be used together with terephthalic acid in consideration of economical properties and finished product properties.

The glycol which carries out the ester reaction with the dicarboxylic acid component is composed of an aliphatic diol having 2 to 16 carbon atoms, an alicyclic diol having 6 to 24 carbon atoms, an aromatic diol having 6 to 24 carbon atoms, and an ethylene oxide or propylene oxide adduct thereof. One or more types selected from the group can be mentioned. More specifically, the glycols that can be used to prepare the polyesters of the invention include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5 -Pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-dodecanediol, diethylene glycol C2-C, such as trimethylene glycol, tetramethylene glycol, hexamethylene glycol, triethylene glycol, tetraethylene glycol, tetramethyl ethylene glycol, pentaethylene glycol, hexaethylene glycol, octaethylene glycol, dipropylene glycol, tripropylene glycol, etc. C6-C24, such as alkanediol of 16, cyclohexanediol, cyclohexanedimethanol, cyclohexanediethanol, cyclohexanedipropanol, cyclohexanedibutanol, cyclohexanedipentanol, cyclobutanedimethanol, cyclopentanedimethanol Alicyclic diols, and non Phenol A, can be cited as aromatic diols having 6 to 24, such as bisphenol S, ethylene oxide or propylene oxide adducts of these diol components.

The process for producing such a polyester polymer is to be applied to a TPA (Terephthalic Acid) process for reacting and esterifying a dicarboxylic acid component, that is, an aromatic dicarboxylic acid and an aliphatic dicarboxylic acid with a glycol component which is a dihydric alcohol. Can be. The general polyester TPA method is a direct reaction in which an acid reaction is carried out without using a catalyst in an ester reaction in which the dicarboxylic acid and glycol are esterified. For example, as shown in following Reaction Scheme 1, the method of producing polyethylene terephthalate (PET) directly by esterification of tetraphthalic acid and ethylene glycol is mentioned.

[Reaction Scheme 1]

This TPA reaction requires high temperatures to be maintained due to insolubility and low reactivity of the dicarboxylic acids. The oligomer prepared as described above may be subjected to a polycondensation reaction at high temperature while adding a catalyst under high vacuum to obtain a polymer having a predetermined viscosity. The polymer thus produced is discharged through a nozzle using a gear pump or a high pressure inert gas (N ₂ ). The polymer thus discharged is solidified with cooling water and cut into suitable sizes.

When preparing polyester according to the conventional TPA method as described above, a carboxyl end group is generated by pyrolysis generation by ester reaction and polycondensation reaction proceeding at high temperature, and dicarboxylic acid having carboxyl end group as a raw material is used. By use, the resulting polyester final polymer contains a large amount of carboxyl end groups. In addition, in the case of applying a polyester yarn containing a large amount of carboxyl end groups to the fabric for the air bag, as described above, the terminal carboxyl group existing as an acid under high temperature and high humidity causes the existing molecular chain cleavage, thereby reducing the physical properties of the fabric Is caused. In this aspect, the present invention performs low-temperature polymerization by optimizing the polycondensation and solid-phase polymerization of the dicarboxylic acid and diol components in mild conditions, and not only minimize the content of such carboxyl end groups, but also through additional solid-phase polymerization By combining terminal carboxyl groups and hydroxyl groups, the molecular weight of the polymer can be increased while reducing the content of CEG.

On the other hand, when the polyester is manufactured using dicarboxylic acid and ethylene glycol according to the general TPA method as described above and fabricated to make the fabric, the shrinkage rate is lower than that of nylon, so the rigidity of the fabric structure is lowered, the air permeability is significantly lowered Fabric slippage occurs at the stitching area and tearing stiffness is also reduced. In addition, when manufacturing the airbag with such a fabric, the airbag is damaged by a strong pressure during the airbag deployment may not be able to play a role of protecting the occupant of the existing airbag.

Therefore, in the present invention, in the preparation of the polyester polymer, the aromatic dicarboxylic acid having 6 to 24 carbon atoms and the aliphatic dicarboxylic acid having 2 to 24 carbon atoms are added together with glycol in a predetermined range to undergo ester reaction and polycondensation. It is possible to manufacture high shrinkage yarns of high strength and low modulus. That is, by adding an aliphatic dicarboxylic acid together with an aromatic dicarboxylic acid in the ester reaction with glycol, a linear structure is introduced in place of the benzene ring in the molecular chain to reduce the rigidity of the molecular chain, thereby reducing the attraction between the molecular chains. Can be. As a result, the movement of the molecules themselves can be made free, so that the structure that can be easily deformed by heat, that is, the heat shrinkage can be facilitated. In addition, according to the present invention, by using a high viscosity chip (Chip) to perform low-temperature spinning and to minimize the radial tension in the delayed cooling portion, to secure a high viscosity filament (filament) even at low elongation of high strength, high shrinkage The yarn can be manufactured.

In addition, the polyester yarn obtained by reacting glycol with an aromatic dicarboxylic acid having 6 to 24 carbon atoms and an aliphatic dicarboxylic acid having 2 to 24 carbon atoms is not only low modulus and high strength but also has high shrinkage characteristics. . As a result, when manufacturing the airbag fabric using such yarn, it prevents the fabric from slipping and tearing due to internal pressure during airbag deployment, and also improves air permeability, thereby protecting the occupant from impact.

Meanwhile, in the present invention, esterification and polycondensation of the aromatic dicarboxylic acid having 6 to 24 carbon atoms and aliphatic dicarboxylic acid having 2 to 24 carbon atoms and glycol may be performed according to a conventional method known as TPA method. It is not specifically limited to other process conditions.

However, according to one preferred embodiment of the present invention, the molar ratio of the dicarboxylic acid component and glycol in the ester reaction step, that is, the total amount of the aromatic dicarboxylic acid and aliphatic dicarboxylic acid and the molar ratio of glycol is 1: 1 to 1: 1.5, preferably 1: 1.1 to 1: 1.45, more preferably 1: 1.1 to 1: 1.4. In this case, the molar ratio of the dicarboxylic acid component and glycol may be 1: 1 or more in terms of improving the process efficiency of the polymerization reaction, and may be 1: 1.5 or less in consideration of the CEG and DEG content of the polymer.

In addition, the molar ratio of the aromatic dicarboxylic acid and aliphatic dicarboxylic acid may be 1: 0.01 to 1: 0.15, preferably 1: 0.01 to 1: 0.14, more preferably 1: 0.01 to 1: 0.13. At this time, the molar ratio of the aliphatic diol and the alicyclic diol may be 1: 0.01 or more in terms of excellent physical properties when processing the fabric for airbags, and may be 1: 0.15 or less in terms of improving yarn manufacturing process efficiency.

The ester reaction may be carried out at 230 to 300 ℃, preferably 250 to 290 ℃, the reaction time may be carried out for 2 hours to 7 hours, preferably 3 to 5 hours. At this time, the reaction time and the reaction temperature can be carried out by adjusting in terms of improving the physical properties and productivity of the polymer.

In the present invention, the polycondensation reaction may be performed at a temperature of 250 to 290 ° C., preferably 270 to 285 ° C., and may be performed at a pressure of 2 Torr or less and preferably 1 Torr or less. At this time, the reaction time may be carried out for 2 to 5 hours, preferably 3 to 4 hours, the reaction time and the reaction temperature may be carried out by adjusting in terms of improving the physical properties and productivity of the polymer.

In particular, the polycondensation reaction can be adjusted to a low level of the viscosity of the molten polymer through low-temperature polymerization, preferably the intrinsic viscosity of the polymer produced after the polycondensation reaction is 0.4 dl / g or more or 0.4 to 0.80 dl / g To be more preferable, it is preferable to adjust the amount to be 0.5 dl / g or more in terms of minimizing the carboxyl group at the end of the polymer.

The polymer produced after the polycondensation reaction minimizes the size of the chip so as to minimize the internal / external reaction difference and increase the reaction rate in the next solid phase polymerization step, that is, the specific surface area of the chip is reduced. It can be used larger. In addition, preferably, the polymer produced after the polycondensation reaction has a chip size of 1.0 g / 100ea to 3.0 g / 100ea so as to increase a specific surface area, more preferably 1.5 g / 100ea to 2.5 g / 100ea. It may be cleaved so as to perform solid phase polymerization.

In this case, the shape of the polymer chip may be prepared by using a spherical shape in order to prevent fusion during the solid phase polymerization. Such spherical, ie, polymer chips in the form of balls or beads may be manufactured by underwater cutting. The polymer chip may be manufactured, for example, by cutting a polymer while making a knife in water to make pellets. In particular, since the polymer pellets cut in water are surrounded by water immediately after cutting, the adhesion of the pellets to each other can be minimized and can be approximately spherical until cooled. That is, since the polymer has an elastomeric substrate, the polymer may be rolled round to produce chips having a shape close to an ellipse or a sphere. In the present invention, the spherical polymer chip may have a cross section of a circle or ellipse shape.

The solid phase polymerization reaction may be carried out at a temperature of 200 to 240 ℃, preferably 205 to 235 ℃, it may be carried out at a pressure of 2 Torr or less, preferably 1 Torr or less. At this time, the reaction time may be carried out for 10 hours or more or 10 to 40 hours, the reaction time and the reaction temperature may be carried out by adjusting in terms of improving the final viscosity and radioactivity.

In the present invention, by performing a low-temperature polymerization of mildly polycondensation reaction of the melt polymerization and proceeding a solid phase polymerization as an additional reaction, by combining the resulting carboxyl end group (CEG) with a hydroxyl group to reduce the CEG content And increase the molecular weight of the polymer.

The polyester polymer further subjected to solid phase polymerization may have an intrinsic viscosity of at least 0.7 dl / g or at least 0.7 to 2.0 dl / g, preferably at least 0.85 dl / g, more preferably at least 0.90 dl / g. It is preferable to improve the physical properties and the radioactivity of the yarn. The intrinsic viscosity of the chip should be 0.7 dl / g or more to prepare a yarn having desirable high strength and high elongation characteristics. However, as described above, in order to manufacture a high-strength low modulus polyester yarn, melt spinning using a high-viscosity polyester polymer, for example, a polyester polymer having an intrinsic viscosity of 0.85 dl / g or more in an unstretched yarn manufacturing process And it is desirable to effectively lower the modulus by maintaining the high viscosity range through the stretching process to exhibit high strength with low stretching. In addition, it is more preferable that the intrinsic viscosity is 2.0 dl / g or less in order to prevent the molecular chain cutting and the pressure increase due to the discharge amount in the spinning pack due to the rise of the melting temperature of the polyester polymer.

In addition, in order to maintain a good physical properties even under high temperature and high humidity conditions when applied to the fabric for the air bag by using a polyester yarn, the molecular weight of the polyester polymer is preferably 30 meq / kg or less. Here, the CEG content of the polyester polymer is maintained in the lowest range even after the process of melt spinning and stretching, so that the final polyester yarn is characterized by high strength and excellent morphological stability, mechanical properties, excellent properties of expression properties under severe conditions It is desirable to be able to secure. In this respect, if the CEG content of the polyester polymer exceeds 30 meq / kg, the intramolecular CEG content of the polyester yarn finally produced through melt spinning and stretching processes is excessive, such as 30 meq / kg to 50 meq. Increasing to more than / kg, the ester bond is cleaved by the CEG under high humidity conditions may cause a decrease in the properties of the yarn itself and the fabric produced therefrom.

Preferably, the polyester polymer contains polyethylene terephthalate (PET) as a main component, and in order to secure excellent mechanical properties as a yarn for airbags, it preferably contains 70 mol% or more, more preferably 90 mol% or more. Can be.

On the other hand, the polyester yarn manufacturing method of the present invention melt-spun the polyester polymer of the high intrinsic viscosity and low CEG content to produce a polyester non-drawn yarn.

At this time, in order to obtain a polyester undrawn yarn satisfying a low initial modulus and a high elongation range, it is preferable that the melt spinning process is performed in a low temperature range so as to minimize pyrolysis of the polyester polymer. In particular, the low-temperature spinning, for example, 270 to the intrinsic viscosity and CEG content of the high-viscosity polyester polymer to minimize the decrease in physical properties according to the process, that is, to maintain the high viscosity and low CEG content of the polyester polymer It may be carried out at a temperature of 300 ℃, and may be carried out at a temperature of preferably 275 ℃ or more, more preferably 280 ℃ or more for efficient spinning process performance. Here, the spinning temperature refers to the extruder temperature, and when the melt spinning process is performed above 300 ° C., thermal decomposition of the polyester polymer occurs in a large amount, thereby lowering the intrinsic viscosity and increasing the CEG content. May be large, and the surface damage of the yarn may result in deterioration of overall physical properties, which is undesirable. On the contrary, when the melt spinning process is performed at less than 270 ° C., melting of the polyester polymer may be difficult, and radioactivity may be deteriorated by N / Z surface cooling, and thus, the melt spinning process may be performed within the above temperature range. Do.

As a result of the melt spinning process of the polyester polymer in this low temperature range, the decomposition reaction of the polyester polymer is minimized to maintain a high intrinsic viscosity to secure a high molecular weight, thereby achieving a high stretching ratio in a subsequent stretching process. It is found that a yarn of high strength can be obtained without applying, and thus, a low drawing process can be performed, thereby effectively lowering the modulus, thereby obtaining a polyester yarn satisfying the above-described physical properties.

In addition, the melt spinning process can be carried out in a manner that minimizes the polyester polymer decomposition reaction, so that the melt spinning process can be carried out under a lower radiation tension, that is, to minimize the spinning tension, It can be controlled at a low speed of 300 to 1,000 m / min, preferably 350 to 700 m / min. This selective progression of the melt spinning process of the polyester polymer under low radiation tension and low spinning rate can further minimize the decomposition reaction of the polyester polymer.

On the other hand, the unstretched yarn obtained through this melt spinning process exhibits an intrinsic viscosity of at least 0.8 dl / g or 0.8 dl / g to 1.2 dl / g, preferably at least 0.85 dl / g, more preferably at least 0.90 dl / g. Can be. In addition, the CEG content in the molecule of the unstretched yarn obtained through low temperature spinning may be 50 meq / kg or less, preferably 40 meq / kg or less, and more preferably 30 meq / kg or less. The intramolecular CEG content of these untwisted yarns can be maintained at the same level in the stretched yarn, that is, the polyester yarn, which has undergone the subsequent stretching process.

In particular, such a high viscosity and low CEG content polyester polymer performs melt spinning under the low temperature conditions as described above to suppress the thermal decomposition of the polyester polymer as much as possible, thereby intrinsic viscosity and CEG content of the polyester polymer and the polyester yarn The difference can be minimized. For example, melt spinning and subsequent processes may be performed such that the difference in intrinsic viscosity between the polyester polymer and the polyester yarn is 0.5 dl / g or less or 0 to 0.5 dl / g, preferably 0.4 dl / g or less. In an actual process, the difference in intrinsic viscosity may be expressed as 0.1 dl / g or more. In addition, the difference in the intramolecular CEG content between the polyester polymer and the polyester yarn may be carried out to 20 meq / kg or less or 0 to 20 meq / kg, preferably 15 meq / kg or less, in the actual process The CEG content difference may appear to be more than 3 meq / kg.

The present invention by suppressing the decrease in the intrinsic viscosity and increase in the CEG content of the polyester polymer as described above, it is possible to ensure excellent elongation while maintaining excellent mechanical properties of the polyester yarn, high strength low modulus yarn suitable for airbag fabric Can be prepared.

And, the polyester polymer, for example PET chip, is preferably spun through a mold designed such that the fineness of the monofilament can be 0.5 to 20 denier, preferably 1 to 15 denier. That is, the denier of the monofilament should be 1.5 denier or more in order to reduce the possibility of the trimming caused by the interference between each other during the generation of the trimming during the spinning and cooling, and the fineness of the monofilament should be 15 denier or less to increase the cooling efficiency. .

In addition, after melt spinning the polyester polymer, a cooling step may be added to produce the polyester non-drawn yarn. It is preferable that the cooling process is performed by applying cooling wind at 15 to 60 캜, and it is preferable to adjust the cooling air flow rate at 0.4 to 1.5 m / s under each cooling wind temperature condition. As a result, it is possible to more easily produce a polyester non-stretched yarn showing physical properties according to an embodiment of the invention.

On the other hand, after the polyester undrawn yarn is produced through such a spinning step, the undrawn yarn is stretched to produce a drawn yarn. In this case, the stretching process may be performed under a stretching ratio of 5.0 to 6.0, preferably 5.0 to 5.8. In particular, in the stretching step, the polyester unstretched yarn passes through GR 1 and GR 2, and then stretches at a draw ratio of 3.0 to 5.0, preferably 3.2 to 4.8, between GR 2 and GR 3, and GR 3 and GR. It can proceed at a draw ratio of 1.0 to 2.0, preferably 1.2 to 1.8, between four.

The polyester non-drawn yarn is optimized to melt spinning process to maintain a high intrinsic viscosity and low initial modulus and to minimize the intramolecular CEG content. Therefore, when the drawing process is carried out under a high draw ratio condition of more than 6.0, it may be over-stretched, so that cutting or wool may occur in the drawn yarn, and a yarn having a low elongation and high modulus may be manufactured by a high degree of fiber orientation. . In particular, when the elongation of the yarn is lowered and the modulus is increased under such high draw ratio conditions, the folding and storage properties may be poor when applied as an airbag fabric. On the other hand, when the drawing process is performed under a relatively low draw ratio, the fiber orientation is low, and the strength of the polyester yarn manufactured therefrom may be partially lowered. However, when the stretching process is performed under a stretching ratio of 5.0 or more in terms of physical properties, for example, a high strength low modulus polyester yarn suitable for application to an airbag fabric, etc. can be manufactured, and thus, the stretching process may have a stretching ratio of 5.0 to 6.0. It is preferable to proceed under conditions.

According to another suitable embodiment of the present invention, a melt spinning process using a high viscosity polyester polymerized chip to produce a low modulus polyester yarn while simultaneously satisfying the properties of high strength and low shrinkage in a direct spinning process, The process may include stretching, heat setting, relaxing and winding up through a multi-stage high-speed roller to wind up the winder.

The stretching process may be performed after passing the undrawn yarn through the godet roller under the condition of an oil pick-up amount of 0.2% to 2.0%.

In the relaxation process, the relaxation rate is preferably 1% to 10%, and when less than 1%, it is difficult to express the shrinkage rate, and it may be difficult to manufacture high elongation low modulus fibers according to the formation of high fiber orientation as in high draw ratio conditions. If it exceeds 10%, the noise on the high-speed roller becomes severe and workability cannot be secured.

In addition, the stretching process may further perform a heat-setting process for heat-treating the undrawn yarn at a temperature of approximately 170 to 250 ℃, preferably 175 to 245 ℃, more preferably for the proper progress of the stretching process May be heat-treated at a temperature of 180 to 240 ℃. If the temperature is less than 170 ° C, the thermal effect is insufficient and the relaxation efficiency is low to achieve the shrinkage rate. When the temperature exceeds 250 ° C, the yarn strength is lowered due to pyrolysis and the tar is increased. .

At this time, the winding speed may be 2,000 to 4,000 m / min, preferably 2,500 to 3,700 m / min.

On the other hand, according to another embodiment of the invention, there is provided a polyester yarn produced through the method as described above. Such polyester yarns can be prepared by melt spinning a polyester polymer, for example PET chips, as described above, to produce undrawn yarns, and stretching the undrawn yarns, as described above, Specific conditions or processing methods may be directly or indirectly reflected on the physical properties of the polyester yarn to produce a polyester yarn having predetermined characteristics.

In particular, the polyester yarn produced through such process optimization is not only low modulus, high strength, but also has characteristics of high shrinkage. As a result, when manufacturing an airbag fabric using such a polyester yarn, it is possible to prevent the fabric from slipping and tearing due to internal pressure during airbag deployment and to significantly improve air permeability, and at the same time minimize the impact on passengers. It turns out that you can.

Polyester yarns produced according to the invention have an initial modulus of 40-100 g / d, elongate at least 0.5% when subjected to 1.0 g / d of stress at room temperature, and 4.3 when subjected to stress of 4.0 g / d. It has been found that polyester yarns for airbags that stretch by more than 7.5% can be secured when stretched by more than% and subjected to a stress of 7.0 g / d. In addition, the optimization of the melt spinning and stretching process in the present invention, it is possible to minimize the carboxyl end group (CEG, Carboxyl End Group) which is present as an acid under high humidity conditions to cause the basic molecular chain cleavage of polyester yarn It turns out that. Therefore, such a polyester yarn exhibits a low initial modulus and a high elongation range at the same time, and thus can be preferably applied to fabrics for airbags having excellent mechanical properties and storage properties, shape stability, impact resistance, and air blocking effect.

In general, polyester has a structure of high stiffness compared to nylon due to its molecular structure, and thus exhibits high modulus characteristics, and when used as a fabric for airbags, the folding and packing properties are remarkably reduced, resulting in a narrow automobile. Storage in the space becomes difficult. By the way, the polyester yarn obtained through the controlled melt spinning and stretching process exhibits properties of high strength low modulus and is lower in initial modulus than previously known polyester industrial yarns, i.e. 40 to 100 g / d, preferably 50 An initial modulus of from 100 to 100 g / d, more preferably from 55 to 95 g / d.

In this case, the modulus of the polyester yarn is a physical property value of the elastic modulus obtained from the slope of the elastic section of the stress-strain diagram obtained in the tensile test, and when the object is stretched from both sides, the elastic modulus indicating the degree of stretching and deformation of the object The value corresponds to In addition, the initial modulus of the yarn is the modulus value of the elastic modulus at the point where the elastic section starts after the "0" point in the stress-strain. If the initial modulus of the yarn is high, the elasticity is good, but the stiffness of the fabric may be poor. If the initial modulus is too low, the stiffness of the fabric may be good, but the elasticity of the fabric may be low, and thus the toughness of the fabric may be deteriorated. By the way, the polyester yarn of the present invention is optimized in the range that the initial modulus is much lower than the conventional polyester industrial yarn. As such, fabrics for airbags made from polyester yarns having a lower initial modulus than conventional ones solve high stiffness problems of conventional polyester fabrics, and exhibit excellent folding, flexibility, and storage properties. Can be.

The polyester yarn also has a feature of minimal elongation with low initial modulus. For this reason, when the polyester yarn is subjected to a stress of 1.0 g / d at room temperature, the polyester yarn may be stretched at least 0.5% or 0.5% to 1.5%, preferably 0.7% to 1.2%, and subjected to a stress of 4.0 g / d. At least 4.3% or 4.3% to 20%, preferably 4.3% to 15%, and at least 7.5% or 7.5% to 25%, preferably 7.5% to 20% when subjected to a stress of 7.0 g / d. It can be stretching. Due to this property, the airbag fabric manufactured from the polyester yarn can solve the high stiffness problem of the existing polyester fabric, and can exhibit excellent folding property, flexibility, and storage property.

It is preferable that such polyester yarn contains polyethylene terephthalate (PET) as a main component. At this time, the PET is a variety of additives can be added in the manufacturing step, in order to exhibit suitable properties for the fabric for the air bag may be a yarn containing at least 70 mol% or more, more preferably 90 mol% or more. have. Hereinafter, the term PET means a case where the PET polymer is 70 mol% or more without any special explanation.

At the same time, the polyester yarn has an improved intrinsic viscosity, i.e., 0.8 dl / g or more or 0.8 dl / g to 1.2 dl / g, preferably 0.85 dl / g to 1.15 dl /, as compared to previously known polyester yarns. g, more preferably 0.90 dl / g to 1.10 dl / g. Intrinsic viscosity is preferably secured in the above range in order to prevent thermal deformation in the coating process, etc. when the polyester yarn is applied to the air bag.

The intrinsic viscosity of the yarn should be 0.8 dl / g or more to exert high strength at low stretching to satisfy the required strength of the airbag yarn, and otherwise it may be forced to express physical properties with high stretching. When high stretching is applied, the degree of orientation of the fiber is increased to obtain high modulus properties. Therefore, it is preferable to maintain the intrinsic viscosity of the yarn at 0.8 dl / g or more to enable low modulus expression by applying low stretching. In addition, since the yarn viscosity is greater than 1.2 dl / g, the stretching tension may increase during stretching, which may cause a process problem, so 1.2 dl / g or less is more preferable. In particular, the polyester yarn of the present invention maintains such a high degree of intrinsic viscosity, while providing low ductility with low stretching, and at the same time can provide sufficient mechanical properties, impact resistance, toughness, etc. for the fabric for the airbag. The high strength characteristic which can be further given.

Therefore, it is possible to manufacture a fabric for an airbag which simultaneously exhibits excellent mechanical properties and storage properties, form stability, impact resistance, and air barrier effect by using a polyester yarn exhibiting such low initial modulus and high elongation, preferably high intrinsic viscosity. Become. Therefore, by using the polyester yarn, it is possible to obtain a fabric for an air bag, which exhibits lower ductility and folding property, flexibility, and storage property, but also exhibits excellent impact resistance, shape stability, mechanical properties, and airtightness. These polyester fabrics for airbags exhibit excellent mechanical properties, shape stability, and air barrier effects, while providing excellent folding properties and storage properties when mounted in tight spaces of cars, while minimizing the impact on passengers with excellent flexibility. Since it can protect, it can be preferably applied as a fabric for airbags.

In addition, the polyester yarns of the present invention may be prepared under melt spinning and stretching conditions as described above, resulting in significantly lower carboxyl end group (CEG) content compared to previously known polyester yarns. That is, the polyester yarn may exhibit a CEG content of 50 meq / kg or less, preferably 40 meq / kg or less, more preferably 30 meq / kg or less. The carboxyl end groups (CEG) in the polyester molecular chains attack ester bonds at high temperature and high humidity to cause molecular chain breakage, thereby degrading physical properties after aging. Particularly, if the CEG content exceeds 50 meq / kg, the ester bond is cleaved by the CEG under high humidity conditions when the air bag is used for application, so that the physical property is degraded, so the CEG content is preferably 50 meq / kg or less. Do.

Meanwhile, the polyester yarn according to the embodiment of the present invention has a tensile strength of 7.5 g / d or more or 7.5 g / d to 11.0 g / d, preferably 8.0 g / d or more or 8.0 g / d to 10.0 g /. d, and elongation at break may be at least 13% or 13% to 35%, preferably at least 14% or 14% to 25%. In addition, the yarn may exhibit a dry heat shrinkage of 3.5% or more or 3.5% to 12%, preferably 4.0% or more. As described above, by securing the intrinsic viscosity, initial modulus, and elongation range in an optimum range, the polyester yarn of the present invention can not only secure strength and physical properties to an excellent degree, but also exhibit excellent performance when manufactured as a fabric for airbags. Can be. In particular, by optimizing and maintaining the dry heat shrinkage of the polyester yarn to a high level as described above, it is possible to effectively control the morphological stability, air permeability, deactivation resistance, etc. of the fabric through high shrinkage at the same time.

In addition, the polyester yarn of the present invention preferably has a shrinkage stress of 0.005 to 0.075 g / d at 150 ℃ corresponding to the laminate coating temperature of the general coating fabric, at 200 ℃ corresponding to the sol coating temperature of the general coating fabric It is preferable that the shrinkage stress of is 0.005 to 0.075 g / d. That is, the shrinkage stress at 150 ° C. and 200 ° C. should be 0.005 g / d or more, respectively, to prevent sagging of the fabric due to heat during the coating process, and should be 0.075 g / d or less to be cooled at room temperature after the coating process. Relaxation stress can be alleviated. The shrinkage stress is based on values measured under a fixed load of 0.10 g / d.

As described above, in order to prevent deformation in heat treatment processes such as coating, the polyester yarn also has a crystallinity of 35% to 60%, preferably 40% to 53%, more preferably 41% to 50%. Can be. The degree of crystallinity of the yarn is preferably at least 35% to maintain thermal form stability when applied to the fabric for airbags, and when the crystallinity is greater than 60%, the problem that the impact absorption performance is deteriorated due to the decrease in the amorphous region is reduced. It is preferable that it can become 60% or less.

In addition, the polyester yarn may be a single yarn fineness of 0.5 to 20 denier, preferably 2.0 to 10.5 denier. In order to effectively use the polyester yarn in the airbag fabric, it is necessary to maintain low fineness and high strength in terms of storage, so that the total fineness of the applicable yarn is 200 to 1,000 denier, preferably 220 to 840 denier, more preferably 250 To 600 denier. In addition, the more filaments of the yarn may give a soft touch, but in the case of too many yarns, the radioactivity may not be good, so the number of filaments may be 50 to 240, preferably 55 to 220, and more preferably 60 to 200. Can be.

On the other hand, according to another embodiment of the invention, there is provided a polyester fabric for an air bag comprising the polyester yarn described above.

In the present invention, the airbag fabric refers to a woven fabric or a nonwoven fabric used for manufacturing an airbag for an automobile, and is characterized by being manufactured using a polyester yarn manufactured through the process as described above.

In particular, the present invention by using a polyester fiber having a high shrinkage characteristics of high strength-high elongation low modulus, rather than the existing polyester fibers having high strength-low elongation and high modulus, the energy absorption ability at the time of inflating the air bag will be excellent In addition, it is possible to provide a polyester fabric for airbags having excellent shape stability, air barrier property, and excellent folding property, flexibility, and storage property. In addition, the airbag fabric is not only excellent in room temperature physical properties, but also maintains excellent mechanical properties and airtightness after aging (aging) under severe conditions of high temperature and high humidity.

More specifically, the airbag fabric of the present invention is a tensile strength of 220 kgf / inch or 220 to 350 kgf / inch, preferably 230 kgf / inch measured at room temperature by the American Society for Testing and Materials Standard ASTM D 5034 method Can be. In the case of the tensile strength, it is preferable to be 220 kgf / inch or more in terms of properties of existing airbags, and in reality, it is preferable to be 350 kgf / inch or less in terms of physical properties.

The fabric for the air bag may be 20% or more, or 20% to 60%, preferably 30% or more, measured at room temperature by the American Society for Testing and Materials Standard ASTM D 5034 method. In the case of the cutting elongation, it is preferable to be 20% or more in terms of physical properties required for existing air bags, and in reality, it is preferable to be 60% or less in terms of physical properties.

In addition, since the coating material for airbags is rapidly expanded by hot-high pressure gas, an excellent tear strength level is required. The tear strength indicating the burst strength of the coating fabric for airbags is determined by the American Society for Testing and Materials ASTM D 2261 method. When measured at room temperature may be 23 kgf or more or 23 to 60 kgf, preferably 25 kgf or more. Here, when the tear strength of the coated fabric is less than the lower limit, that is, 23 kgf at room temperature, the airbag may burst when the airbag is deployed, which may cause a great risk to the airbag function.

Fabric for airbags according to the present invention has a sliding resistance of at least 380 N or 380 to 1,000 N, preferably 400 N or more, more preferably 420, measured at room temperature (25 ° C.) by the American Society for Testing and Materials Standard ASTM D 6479 method. Can be greater than or equal to N. In addition, the polyester fabric may be 300 N or more or 320 to 970 N, preferably 310 N or more, more preferably 320 N or more measured at 90 ℃. At this time, the deactivation resistance of the polyester fabric is measured at room temperature (25 ℃) and 90 ℃, when less than 380 N and less than 300 N, respectively, the fabric strength of the airbag cushion sewing area is sharply worse when the air bag deployment, the actual air bag deployment In the fabric, a pinhole and a tearing of the fabric may occur due to a bark push phenomenon, which may be undesirable.

In addition, the fabric for the airbag according to the present invention may be less than 4.0%, preferably less than 2.0% of the fabric shrinkage in the warp direction and the weft direction, respectively, measured by the ASTM D 1776 method. Here, in terms of the shape stability of the fabric, it is most preferable that the fabric shrinkage ratio in the warp direction and the weft direction do not exceed 1.0%.

The fabric may have an air permeability of 10.0 cfm or less, or 0 to 10.0 cfm, measured at room temperature by the American Society for Testing and Materials Standard ASTM D 737 method. In particular, the air permeability of the fabric for the airbag can be significantly lowered by including the rubber component coating layer in the fabric, it is possible to ensure the air permeability of the value close to almost 0 cfm. However, when the rubber coating is not carried out, the uncoated fabric of the present invention has an air permeability of 10.0 cfm or less or 0 to 10.0 cfm, preferably 3.5, measured at room temperature by the American Society for Testing and Materials Standard ASTM D 737 method. cfm or less, or 0.1 to 3.5 cfm, more preferably 1.5 cfm or less, or 1.0 cfm or less. At this time, when the air permeability exceeds 10.0 cfm, more preferably 3.5 cfm, it may not be preferable in terms of maintaining the airtightness of the fabric for the airbag.

In addition, the fabric for the air bag of the present invention may be less than 1.2 kgf or 0.2 to 1.2 kgf, preferably 1.0 kgf measured at room temperature by the American Society for Testing and Materials Standard ASTM D 4032 method. In particular, when 530 denier or more may be 1.2 kgf or less, when less than 460 denier may have a range of 1.0 kgf or less.

In order to use the fabric of the present invention, it is preferable to maintain the above-described stiffness range, and if the stiffness is too low, less than 0.2 kgf, the protective bag may not have sufficient protective support during airbag expansion and deployment. Even in the case of poor shape retention performance, the storage performance may be reduced. In addition, in order to prevent the deterioration of storage properties by becoming too hard and difficult to fold, and to prevent discoloration of the fabric, 1.2 kgf or less is preferable, and in particular, when less than 460 denier, 1.0 kgf or less is preferable. In the case of more than 530 denier, it is preferable to be 1.2 kgf or less.

On the other hand, according to another embodiment of the invention, there is provided a method of manufacturing a fabric for airbags using the polyester yarn described above. The fabric manufacturing method for the airbag of the present invention includes the steps of weaving the dough for the airbag using the polyester yarn, the step of refining the woven dough for the airbag, and the step of tentering the refined fabric.

In the present invention, the polyester yarn may be produced as a final airbag fabric through a conventional weaving method, refining and tentering process. At this time, the weaving form of the fabric is not limited to a specific form, and both plain weave type and OPW (One Piece Woven) type weaving type are preferable.

In particular, the airbag fabric of the present invention can be manufactured by beaming, weaving, refining, and tentering processes using the polyester yarn as weft and warp yarns. The fabric may be manufactured using a conventional weaving machine, and is not limited to the use of any specific loom. However, plain weave fabrics may be manufactured using a Rapier Loom, an Air Jet Loom, or a Water Jet Loom, and the OPW type fabric may be manufactured using Jacquard looms Loom. ≪ / RTI >

The fabric for the airbag thus manufactured is manufactured in the form of an airbag cushion having a predetermined shape while undergoing cutting and sewing. The airbag is not limited to a particular type and can be manufactured in a general form.

On the other hand, according to another embodiment of the invention, there is provided an airbag system including the airbag.

The airbag system can be equipped with conventional devices well known to those skilled in the art. The airbag can be broadly divided into a frontal airbag and a side curtain airbag. The frontal airbag includes a driver's seat, a passenger's seat, a side protection, a knee protection, an ankle protection, and a pedestrian protection airbag. The side curtain type airbag protects the passenger in the event of a side collision or an overturning accident. Therefore, the airbag of the present invention includes both the front airbag and the side curtain airbag.

In the present invention, matters other than those described above can be added or subtracted as required, and therefore, the present invention is not particularly limited thereto.

According to the present invention, by using a specific aromatic dicarboxylic acid and aliphatic dicarboxylic acid together as a dicarboxylic acid component to react with glycol in an optimum composition range, it has excellent flexibility and folding properties with excellent mechanical properties A method of making a polyester yarn suitable for fabric for airbags is provided.

The polyester yarns produced in this way exhibit high strength, low modulus, and high shrinkage at the same time, so that they can not only obtain excellent form stability, mechanical properties, and air barrier effect when used in airbag fabrics, but also have excellent folding properties and Flexibility is ensured, which significantly improves the storage performance of the car and minimizes the impact on the passengers, thereby protecting the occupants.

Therefore, the polyester yarn manufactured according to the present invention and the polyester fabric using the same can be very preferably used for manufacturing a vehicle airbag.

1 shows a general airbag system.
2 is a process diagram schematically showing a polyester yarn manufacturing process according to an embodiment of the present invention.

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

Examples 1-5

Under the process conditions shown in Table 1, the molar ratio (AA / TPA) of terephthalic acid (TPA) and adipic acid (AA) is 0.02 to 0.12, and the dicarboxylic acid component and ethylene glycol (EG) The ester reaction was carried out for 4 hours between 285 and 292 DEG C with a molar ratio [EG / (TPA + AA)] of 1.3. After the ester reaction, the resulting oligomer was subjected to a polycondensation reaction for 3 hours 30 minutes between 284 to 290 ° C to produce a polymer.

At this time, the polyester polymer (chip) produced through the polycondensation reaction was cut in water using an underwater cutter device was prepared in the form of pellets of a spherical shape such as beads.

Since the produced polyester polymer (chip) in the shape of a sphere does not entangle each other during solid phase polymerization, the solid phase polymerization temperature can be higher than that of the conventional copolymer solid phase polymerization, and here it is 22 ~ 24 at 235 ℃ Solid phase polymerization was further performed for a time to prepare a polyester solid phase polymer chip having an intrinsic viscosity (IV) of 1.3 dl / g.

The polyester solid-state polymerization chip was prepared by spinning and stretching in the process as shown in Figure 2 to prepare a polyester yarn for air bags.

In particular, the polyester solid-state polymerization chip is melted at a temperature of 290 ~ 294 ℃ to discharge the molten polyester through the spinneret, and delayed by passing the discharged molten polyester through a delayed cooling section consisting of a hood-heater and a heat insulating plate Delayed quenching.

The delayed quenched polyester fiber was imparted with an emulsion using an emulsion imparting device in roll form. At this time, the amount of the emulsion is 0.8 parts by weight based on 100 parts by weight of yarn, the emulsion used is ethylene oxide / propylene oxide addition diol ester (30 parts by weight), ethylene oxide addition diol ester (15 parts by weight), glyceryl tri A spinning emulsion comprising an ester (10 parts by weight), trimethylpropane triester (10 parts by weight), and a small amount of antistatic agent was used.

The emulsified yarn was passed through a pre-collector and stretched using a roller.

After the stretching, the second yarn (2 ^nd Interlacer) was used to impart an interconnect to the stretched polyester yarn, and then wound with a winding machine to prepare a polyester yarn.

At this time, the molar ratio of each component, ester reaction, polycondensation reaction, solid state polymerization reaction conditions, intrinsic viscosity of the PET polymer, melt spinning, elongation ratio, heat treatment process conditions such as heat treatment, and the like are shown in Table 1 below, the remaining conditions are poly The usual conditions for the preparation of ester yarns were followed.

division Example 1 Example 2 Example 3 Example 4 Example 5 AA / TPA molar ratio 0.12 0.9 0.07 0.04 0.02 EG / (TPA + AA) molar ratio 1.3 1.3 1.3 1.3 1.3 Ester Reaction Temperature (℃) 285 285 290 290 292 Ester Reaction Time (hr) 4 4 4 4 4 Polycondensation reaction temperature (℃) 284 284 288 290 290 Polycondensation reaction time (hr) 3.5 3.5 3.5 3.5 3.5 Raw Chip IV (dl / g) 0.64 0.65 0.66 0.67 0.67 Solid State Polymerization Reaction Temperature (℃) 235 235 235 235 235 Solid State Polymerization Reaction Time (hr) 24 24 22 23 24 IV after solid state polymerization (dl / g) 1.3 1.3 1.3 1.3 1.3 Chip size (g / 100ea) 2.0 2.0 2.0 2.0 2.0 Radiation temperature (℃) 290 290 292 292 294 Winding speed (m / min) 3,000 3,000 3,000 3,000 3,000 Total mystery 5.91 5.82 5.80 5.75 5.72 Heat treatment temperature (℃) 220 222 222 224 227 % Relaxation 3.4 3.8 4.3 4.5 5.0

Physical properties of the polyester yarns prepared according to Examples 1 to 5 were measured by the following methods, and the measured physical properties are summarized in Table 2 below.

1) Crystallinity

The density ρ of the polyester yarn was measured at 25 ° C. according to the density gradient pipe method using n-heptane and carbon tetrachloride, and the crystallinity was calculated according to the following formula 1.

[Equation 1]

Where ρ is the density of the yarn, ρ _c is the density of the crystal (1.457 g / cm ^{3 for} PET), and ρ _a is the density of the amorphous (1.336 g / cm ^{3 for} PET).

2) intrinsic viscosity

Extract the emulsion from the sample using carbon tetrachloride, melt with OCP (Ortho Chloro Phenol) at 160 ± 2 ° C, and measure the sample viscosity in the viscous tube at 25 ° C using an automatic viscosity meter (Skyvis-4000). To obtain the intrinsic viscosity (IV) of the polyester yarn in accordance with the following formula (2).

[Equation 2]

Intrinsic Viscosity (IV) = {(0.0242 × Rel) + 0.2634} × F

Where

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ego,

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to be.

3) CEG content

Carboxyl End Groups (CEGs) of polyester yarns are prepared by placing 0.2 g of a sample into a 50 mL Erlenmeyer flask, adding 20 mL of benzyl alcohol, according to the requirements of ASTM D 664 and D 4094. plate) up to 180 ℃, hold for 5 minutes to completely dissolve the sample, then cooled to 160 ℃, 5-6 drops of phenolphthalene when the temperature reaches 135 ℃, titrated with 0.02 N KOH, colorless to pink The CEG content (COOH million equiv./kg of sample) was calculated by the following Equation 3 at the titration point.

[Equation 3]

CEG = (A-B) × 20 × 1 / W

Where A is the amount of KOH consumed in the titration of the sample (mL), B is the amount of KOH consumed in the titration of the blank sample (mL), and W is the weight of the sample (g).

4) initial modulus

Initial modulus was measured by calculating the elastic modulus from the slope of the elastic section of the stress-strain graph obtained in the tensile test according to the method of the American Society for Testing and Materials, ASTM D 885.

5) Tensile strength and elongation at break

The tensile strength and the elongation of the polyester yarn were measured using an all-purpose material tester (Instron). The sample length was 250 mm, the tensile speed was 300 mm / min, and the initial load was set at 0.05 g / d.

6) Dry Heat Shrinkage

Dry heat shrinkage was measured for 2 minutes at a temperature of 180 ° C. and ultra-high load (0.05 g / d) using a Testrite MK-V instrument from Testrite, UK.

7) single yarn fineness

The single yarn fineness was measured by taking the yarn of 9,000 m using a bobbin and measuring the total fineness (Denier) of the yarn by dividing it by the number of filaments.

8) Elongation

The tensile strength and the cutting elongation were measured in the same manner as in the method, and an elongation value corresponding to each load was confirmed on the SS curve.

division Example 1 Example 2 Example 3 Example 4 Example 5 Crystallinity (%) 41.8 42.5 43.1 43.5 44.5 Yarn specific viscosity (dl / g) 0.98 0.99 0.99 0.98 0.98 Yarn CEG (meq / kg) 22 23 23 24 24 Initial modulus (g / d) 73 76 80 82 84 Tensile strength (g / d) 9.1 8.9 8.9 9.1 9.2 Cutting Elongation (%) 23.2 22.5 21.5 20.9 20.7 Dry heat shrinkage (%) 9.9 9.5 8.6 7.5 6.7 Single Sand Island (de) 9.8 8.8 7.6 6.8 5.8 Total fineness (de) 7.7 7.7 8.3 4.2 4.7 Filament number 460 460 500 500 460 Elongation
(%) At 1.0 g / d stress 0.89 0.87 0.83 0.81 0.80 At 4.0 g / d stress 9.9 9.7 9.6 9.4 9.2 7.0 g / d stress 15.8 15.6 15.3 14.7 14.5

Comparative Examples 1 to 5

According to the same method as in Examples 1 to 5, except that the conditions described in Table 3 were applied, and the polymer chips in the form of cylinders were manufactured in a strand manner rather than underwater cutter devices. Polyester yarns of Comparative Examples 1 to 5 were prepared.

In particular, Comparative Examples 1 and 2 did not include separate adipic acid, and the ester reaction was performed using terephthalic acid.

division Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 AA / TPA molar ratio - - 0.17 0.22 0.28 EG / (TPA + AA) molar ratio 1.3 1.2 1.3 1.3 1.3 Ester Reaction Temperature (℃) 290 295 285 283 280 Ester Reaction Time (hr) 4 4 4 4 4 Polycondensation reaction temperature (℃) 295 300 295 295 295 Polycondensation reaction time (hr) 3.5 3.5 3.5 3.5 3.5 Raw Chip IV (dl / g) 0.66 0.67 0.63 0.63 0.64 Solid State Polymerization Reaction Temperature (℃) 240 240 225 220 215 Solid State Polymerization Reaction Time (hr) 26 26 28 32 35 IV after solid state polymerization (dl / g) 1.3 1.3 1.3 1.3 1.3 Chip size (g / 100ea) 3.5 3.5 3.5 3.5 3.5 Radiation temperature (℃) 305 305 302 302 302 Winding speed (m / min) 3,000 3,000 3,000 3,000 3,000 Total mystery 6.15 6.12 6.25 6.35 6.47 Heat treatment temperature (℃) 240 240 215 210 203 % Relaxation 3.5 4.2 3.5 2.6 2.2

Physical properties of the polyester yarn prepared according to Comparative Examples 1 to 5 are summarized in Table 4 below.

division Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Crystallinity (%) 50.5 51.2 34.3 33.5 32.4 Yarn specific viscosity (dl / g) 0.83 0.88 0.87 0.84 0.79 Yarn CEG (meq / kg) 33 35 38 41 41 Initial modulus (g / d) 113 115 118 125 127 Tensile strength (g / d) 8.5 8.8 7.7 6.2 5.3 Cutting Elongation (%) 16.4 16.7 15.7 14.2 12.9 Dry heat shrinkage (%) 3.2 3.6 13.4 14.9 15.2 Single Sand Island (de) 1.25 6.0 6.0 3.0 3.3 Total fineness (de) 200 240 600 700 800 Filament number 160 40 50 230 240 Elongation
(%) At 1.0 g / d stress 0.39 0.41 0.42 0.43 0.44 At 4.0 g / d stress 3.82 3.71 3.81 3.84 3.85 7.0 g / d stress 7.23 7.22 7.23 7.67 7.92

Manufacture example 1-5

Weaving fabric dough for airbags using a rapier weaving machine using polyester yarns prepared according to Examples 1 to 5 (inclined x weft: 41 x 41 to 49 x 49), and for airbags after refining and tenting Fabric was prepared. In addition, the polyvinyl chloride (PVC) resin on the fabric was coated with a resin knife coating method (knife over ro1l coating) in the coating amount coating amount 20 g / m ² range to prepare a PVC coated fabric.

At this time, the remaining fabric manufacturing process conditions were in accordance with the conventional conditions for the production of polyester fabric for airbags.

Meanwhile, the physical properties of the polyester fabrics for the airbags thus prepared were measured by the following method, and the measured physical properties are summarized in Table 5 below.

(a) Tensile strength and elongation at break

The specimen was cut from the airbag fabric and fixed to the lower clamp of the tensile strength measuring device according to the American Society for Testing and Materials, ASTM D 5034. The strength and elongation at the time of breaking the airbag fabric specimen were measured while moving the upper clamp upward.

(b) Tear strength

The tear strength of the fabric for airbags was measured according to the American Society for Testing and Materials, ASTM D 2261.

(c) Fabric shrinkage in warp and weft directions

Fabric shrinkage in the warp / weft direction was measured according to the American Society for Testing and Materials, ASTM D 1776. First, after cutting the specimen from the OPW airbag fabric, mark the length before shrinking in the direction of warp and weft, and measure the contracted length of the specimen heat-treated in the chamber for 1 hour at 149 ° C. Fabric shrinkage ratio of {(length before shrinkage-length after shrinkage) / length before shrinkage × 100%} was measured.

(d) lecture

The ductility of the fabric was measured by the circular bend method using a ductility measuring device according to the American Material Testing Association standard ASTM D 4032. In addition, the cantilever method may be applied as a method of measuring the stiffness, and the stiffness can be measured by measuring the bend length of the fabric using a cantilever measuring device, which is a test bench that is inclined at an angle to give a bend to the fabric.

(e) after

The thickness of the fabric for airbags was measured according to the American Society for Testing and Materials, ASTM D 1777.

(f) air permeability

According to the American Society for Testing and Materials, ASTM D 737, the airbag fabric was allowed to stand at 20 ° C. and 65% RH for at least one day, and then the amount of air passing through a circular section of 38 cm ² was measured at 125 Pa.

(g) bow resistance

The uncoated fabric before coating treatment was used to measure the edge comb resistance of the fabric at room temperature (25 ° C.) by the method according to the American Society for Testing and Materials, ASTM D 6479.

division Preparation Example 1 Preparation Example 2 Production Example 3 Production Example 4 Production Example 5 Tensile strength (kgf / inch) 237 240 242 244 255 Cutting Elongation (%) 38 41 43 46 49 Tear strength (kgf) 25 26 27 27 26 Fabric Shrinkage
(%) slope 1.7 1.6 1.5 1.4 1.4 Weft 1.6 1.5 1.5 1.4 1.3 Lecture degree (kgf) 0.36 0.38 0.40 0.41 0.42 Air permeability (cfm) 0.43 0.40 0.48 0.53 0.55 Deactivation Resistance (N) 590 570 527 522 480

Comparative Production Examples 1 to 5

Except for using the polyester yarn prepared according to Comparative Examples 1 to 5 according to the same method as Preparation Examples 1 to 5 to prepare a polyester fabric for air bags and to measure the physical properties are summarized in Table 6 below.

division compare
Production Example 1 compare
Production Example 2 compare
Preparation Example 3 compare
Production Example 4 compare
Preparation Example 5 Tensile strength (kgf / inch) 222 224 205 180 165 Cutting Elongation (%) 32 30 30 28 25 Tear strength (kgf) 15 14 16 13 10 Fabric Shrinkage
(%) slope 0.5 0.5 3.5 5.2 6.5 Weft 0.4 0.4 2.9 4.5 6.4 Lecture degree (kgf) 1.67 1.70 1.65 1.77 1.66 Air permeability (cfm) 1.58 1.48 1.67 1.44 1.45 Deactivation Resistance (N) 256 213 315 357 360

As shown in Table 5, the fabrics for airbags of Preparation Examples 1 to 5 using the polyester yarns of Examples 1 to 5 prepared by reacting glycol with aromatic dicarboxylic acids and aliphatic dicarboxylic acids in an optimum range are It has been found that it is possible to realize improved stiffness and high edge comb. In particular, in the case of the fabric for airbags of Preparation Examples 1-5, the tensile strength and air permeability are 237-255 kgf / inch and 0.43-0.55 cfm, respectively. In addition, the fabrics for airbags of the production examples 1 to 5 can achieve significantly improved results, in terms of stiffness and degumming resistance, respectively, 0.36 to 0.42 kgf and 480 to 590 N. It can be seen that.

On the other hand, as shown in Table 6, the polyester fabrics of Comparative Preparation Examples 1 to 5 using the polyester yarns of Comparative Examples 1 to 5 are significantly inferior in mechanical properties and airtightness, and do not meet the characteristics of fabric properties for airbags. Confirmed. In particular, the lecture and air permeability are significantly increased to 1.65 ~ 1.77 kgf and 1.44 ~ 1.67 cfm, respectively, it can be seen that the airtightness, etc. can be significantly reduced when mounted with the air bag. In addition, it can be seen that the tensile strength and the slide resistance fall significantly to 165 to 224 kgf / inch and 213 to 360 N, respectively. In this case, when the deactivation resistance and the tensile strength are significantly low, airbag fabric properties may not be satisfied, causing the airbag to burst during airbag deployment.

Claims (26)

Ester-reacting an aromatic dicarboxylic acid having 6 to 24 carbon atoms and an aliphatic dicarboxylic acid having 2 to 24 carbon atoms with glycol;
Polycondensation reaction of the oligomer produced by the ester reaction;
Solid-phase polymerizing the polymer produced by the polycondensation reaction; And
Melt spinning and stretching the polyester chip produced by the solid state polymerization reaction;
Including,
The aromatic dicarboxylic acid, aliphatic dicarboxylic acid, and glycol are such that the molar ratio of the total amount of dicarboxylic acid and glycol is 1: 1 to 1: 1.5, and the molar ratio of aromatic dicarboxylic acid and aliphatic dicarboxylic acid. Is a method of producing a polyester yarn to be reacted to be 1: 0.01 to 1: 0.15. The method of claim 1,
Method for producing a polyester yarn to perform the polycondensation reaction at a temperature of 250 to 290 ℃. The method of claim 1,
Process for producing a polyester yarn to perform the solid phase polymerization reaction at a temperature of 200 to 240 ℃. The method of claim 1,
The aromatic dicarboxylic acid is terephthalic acid, isophthalic acid, phthalic acid, diphenyl ether dicarboxylic acid, biphenyl dicarboxylic acid, 1,4-naphthalene dicarboxylic acid, 1,5-naphthalene dicarboxylic acid and esters thereof Process for producing at least one polyester yarn selected from the group consisting of derivatives. The method of claim 1,
The aliphatic dicarboxylic acid is at least one polyester yarn selected from the group consisting of oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suveric acid, azelaic acid, sebacic acid and ester forming derivatives thereof. Manufacturing method. The method of claim 1,
The glycol is at least one polyester yarn selected from the group consisting of aliphatic diols having 2 to 16 carbon atoms, alicyclic diols having 6 to 24 carbon atoms, aromatic diols having 6 to 24 carbon atoms, and ethylene oxide or propylene oxide adducts thereof. Way. The method of claim 1,
The polymer produced after the polycondensation reaction is a method of producing a polyester yarn having an intrinsic viscosity of 0.4 dl / g or more. The method of claim 1,
The polymer produced after the polycondensation reaction is a method for producing a polyester yarn for airbags to perform a solid-phase polymerization after cutting the chip size to 1.0 g / 100ea to 3.0 g / 100ea. The method of claim 1,
The polymer produced after the polycondensation reaction is a method of producing a polyester yarn for airbags to perform a solid state polymerization by producing a spherical shape of the chip. The method of claim 1,
Process for producing a polyester yarn to perform the solid state polymerization reaction for 10 hours or more. The method of claim 1,
The polyester chip produced after the solid phase polymerization reaction comprises a polyethylene terephthalate 70 mol% or more of the polyester yarn production method. The method of claim 1,
The polyester chip produced after the solid phase polymerization reaction has an inherent viscosity of 0.7 dl / g or more polyester yarn manufacturing method. The method of claim 1,
A method of producing a polyester yarn that melt-spun polyester chips produced by the solid state polymerization reaction at 270 to 300 ℃. The method of claim 1,
Method of producing a polyester yarn melt-spun the polyester chip produced by the solid-phase polymerization reaction under a spinning speed of 300 m / min to 1,000 m / min. The method of claim 1,
A method of producing a polyester yarn that melt-spun the polyester chip produced by the solid-phase polymerization reaction and stretched to a total draw ratio of 5.0 to 6.0. The method of claim 1,
Method of producing a polyester yarn further comprises a heat setting step at 170 to 250 ℃ temperature after the stretching step. The method of claim 1,
Method of producing a polyester yarn further comprises a relaxation step of 1% to 10% relaxation rate after the stretching step. A polyester yarn made by the process according to any one of claims 1 to 17. 19. The method of claim 18,
Polyester yarns with a crystallinity of 35 to 60%. 19. The method of claim 18,
Polyester yarns having a tensile strength of at least 7.5 g / d and an elongation at break of at least 13%. 19. The method of claim 18,
Polyester yarns having an elongation of at least 0.5% at 1.0 g / d stress measured at room temperature, an elongation of at least 4.3% at 4.0 g / d stress, and an elongation of at least 7.5% at a stress of 7.0 g / d. 19. The method of claim 18,
Polyester yarns with an initial modulus of 40 to 100 g / d. A polyester fabric comprising the polyester yarn according to claim 18. 24. The method of claim 23,
The fabric is a polyester fabric having a tear strength of 23 kgf or more measured by the American Society for Testing and Materials Standard ASTM D 2261 method. 24. The method of claim 23,
The fabric is a polyester fabric having a sliding resistance of 380 N or more measured at room temperature (25 ℃) by the American Society for Testing and Materials Standard ASTM D 6479 method. 24. The method of claim 23,
The fabric is a polyester fabric having a hardness of 1.2 kgf or less measured by the American Society for Testing and Materials Standard ASTM D 4032 method.

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