High-strength infrared-absorbing polyester yarn and manufacturing method therefor

Abstract

The present invention relates to a high-strength infrared-absorbing polyester yarn and a method for manufacturing same. In particular, the present invention relates to a high-strength infrared-absorbing polyester yarn which, when used in industrial webbings, safety belts, ropes, fabrics, and the like, has characteristics that appear to be distinguished from ordinary yarns when imaged with an infrared camera due to the infrared absorption performance thereof.

Description

High-strength infrared-absorbing polyester yarn and method for manufacturing the same

[0001] The present invention relates to a high-strength infrared-absorbing polyester yarn and a method for manufacturing the same. More specifically, the invention aims to provide a high-strength infrared-absorbing polyester yarn that, when used in industrial webbing, ropes, fabrics, etc., has the characteristic of being distinguishable from ordinary yarn when photographed with an infrared camera due to its infrared absorption performance.

[0002] Polyester yarns, represented by polyethylene terephthalate (hereinafter referred to as "PET"), are widely used for fibers, films, and resins due to their excellent mechanical strength and chemical resistance. For example, in the case of fibers, they are widely used not only for medical applications but also as reinforcing materials for rubber products such as tire cords, seat belts, and webbing. Among these industrial polyester fibers, high-strength polyester fibers with polyethylene terephthalate as the main component are currently widely used as yarns for seat belts.

[0003] Generally, technological development for polyester fibers used in seat belts has focused solely on increasing strength using high-strength yarns, as the process of making webbing from yarn and dyeing results in a decrease in strength due to high-temperature heat treatment.

[0004] These industrial polyester yarns are frequently required to possess additional physical properties depending on the product, such as infrared absorption performance or electromagnetic shielding performance.

[0005] Infrared-absorbing polyester yarns mainly include naphthalocyanine, phthalocyanine, squarillium, diimonium, nitroso, cyanine, nigrosine, and triphenylmethane compounds, or metal oxides such as tungsten oxide. However, while these conventional infrared-absorbing polyester yarns can be used as clothing materials, they have a low strength of less than 6.0 g / d, so they are not suitable for applications requiring high strength characteristics, such as industrial ropes, belts, and webbing.

[0006] [Prior Art Literature]

[0007] [Patent Literature]

[0008] (Patent Document 1) KR 10-1306579 B

[0009] (Patent Document 2) KR 2022-0146563 A

[0010] (Patent Document 3) KR 2012-0133035 A

[0011] The objective of the present invention is to provide a high-strength infrared-absorbing polyester yarn that incorporates a functional material exhibiting infrared absorption performance into the polyester yarn without a reduction in strength, and a method for manufacturing the same.

[0012] One aspect of the present invention for solving the above-mentioned problem relates to a high-strength infrared-absorbing polyester yarn comprising a carbon-based infrared absorber that absorbs light in the infrared region of wavelength 750 nm to 30000 nm, and composed of polyethylene terephthalate having an intrinsic viscosity of 0.7 to 1.0 dl / g, and having a strength of 8.0 g / d or more.

[0013] The above carbon-based infrared absorber may be carbon black, graphite, carbon nanotubes, or carbon nanofibers.

[0014] The above carbon black has a particle size of 10 to 50 nm and a specific surface area (total surface area of ​​carbon black particles per unit mass) of 90 to 110 m² 2You can use / g.

[0015] The carbon nanotubes are single-walled carbon nanotubes (SWNT), multi-walled carbon nanotubes (MWNT), or composites thereof, and the diameter of the carbon nanotubes may be 1 nm to 50 nm. The content of the carbon-based infrared absorber may be 30 ppm to 10,000 ppm based on the total weight of the high-intensity infrared-absorbing polyester yarn.

[0016] Another aspect of the present invention for solving the above-mentioned problem is,

[0017] A step of preparing a polymer by mixing and melting a polyethylene terephthalate masterbatch having a viscosity (IV) of 0.7 to 1.0 dl / g containing a carbon-based infrared absorber that absorbs light in the infrared region of wavelength 750 nm to 30000 nm, and a polyethylene terephthalate chip having an intrinsic viscosity of 1.0 to 1.2 dl / g;

[0018] The present invention relates to a method for manufacturing a high-strength infrared-absorbing polyester yarn comprising the step of obtaining a polyester yarn by spinning the above-mentioned polymer.

[0019] Another aspect of the present invention for solving the aforementioned problem relates to a safety belt comprising a high-strength infrared-absorbing polyester yarn of the present invention.

[0020] The high-strength infrared-absorbing polyester yarn of the present invention has the advantage of having a reflectance of 70% or less at a wavelength of 950 nm, a strength of 8.0 g / d or more, and good appearance quality.

[0021] Unlike ordinary yarns that appear white in an infrared camera, the yarn of the present invention absorbs light in the infrared region and appears as dark gray to black in an infrared camera, thus having the characteristic of being distinguishable from ordinary yarns.

[0022] By using the polyester yarn of the present invention, it is possible to maintain high strength by reducing strength degradation during the processing process and to reduce the number of warp threads of the fabric for the seat belt, thereby enabling the reduction of the thickness or width of the seat belt and making it possible to manufacture a high-strength yet lightweight seat belt at a low cost.

[0023] Figure 1 is a photograph of polyester yarns manufactured in Example 1 and Comparative Example 2 of the present invention taken with an infrared camera.

[0024] The present invention will be described in more detail below with reference to the drawings attached to the present invention.

[0025] In describing the present invention, specific descriptions of related known functions or configurations are omitted to avoid obscuring the essence of the invention.

[0026] In this application, terms such as "comprising" or "having" are intended to specify the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0027] As used herein, terms of degree such as "approximately," "substantially," etc., are used in the sense of being at or close to the stated value when inherent manufacturing and material tolerances are presented in the mentioned meaning.

[0028] One aspect of the present invention relates to a high-strength infrared-absorbing polyester yarn comprising a carbon-based infrared absorber that absorbs light in the infrared region of wavelength 750 nm to 30,000 nm, and composed of polyethylene terephthalate having an intrinsic viscosity of 0.7 to 1.0 dl / g, and having a strength of 8.0 g / d or more.

[0029] The above carbon-based infrared absorber may be carbon black, graphite, carbon nanotubes, or carbon nanofibers.

[0030] The above carbon black has a particle size of 10 to 50 nm and a specific surface area of ​​90 to 110 m² 2 You can use / g.

[0031] The carbon nanotubes mentioned above are single-walled carbon nanotubes (SWNT), multi-walled carbon nanotubes (MWNT), or composites thereof, and the diameter of the carbon nanotubes may be 1 nm to 50 nm.

[0032] It is preferable that the content of the above carbon-based infrared absorber be 30 ppm to 10,000 ppm based on the total weight of the high-strength infrared-absorbing polyester yarn.

[0033] The above yarn may have a reflectance of 70% or less, 60% or less, 50% or less, 40% or less, or 30% or less at a wavelength of 950 nm.

[0034] In the present invention, the yarn was evaluated based on the masterbatch concentration and input amount at which the reflectance at a wavelength of 950 nm is secured to be 70% or less. Since a reflectance of 70% or less at a wavelength of 950 nm appears gray or black in an infrared camera, it is possible to obtain an effect that distinguishes it from ordinary yarn, which appears bright due to the lack of infrared absorption.

[0035] The manufactured polyester yarn may have a tensile strength of 8.0 to 12 g / d, preferably 8.5 to 11.5 g / d, and more preferably 9.0 to 11 g / d. In this case, if the tensile strength of the polyester yarn is below the above range, the stability of the seat belt webbing may be reduced, and if it exceeds the above range, productivity may be reduced.

[0036] In addition, the fineness of the polyester yarn may be 100 to 3,000 denier, preferably 500 to 2,000 denier, and more preferably 1,000 to 1,500 denier. Furthermore, the single filament fineness of the polyester yarn may be 1 to 20 denier, preferably 5 to 15 denier, and more preferably 8 to 14 denier. At this time, if the fineness of the polyester yarn and the single filament fineness are each below the above ranges, the stability as an industrial fiber may be reduced, and if they exceed the above ranges, the touch feel may be poor when manufactured into a fabric.

[0037] Another aspect of the present invention relates to a method for manufacturing a high-strength infrared-absorbing polyester yarn, comprising the steps of: mixing and melting a polyethylene terephthalate masterbatch having a viscosity (IV) of 0.7 to 1.0 dl / g and a polyethylene terephthalate chip having an intrinsic viscosity of 1.0 to 1.2 dl / g, the masterbatch containing a carbon-based infrared absorber that absorbs light in the infrared region of wavelength 750 nm to 30000 nm to produce a polymer; and spinning the polymer to obtain a polyester yarn.

[0038] First, a polyethylene terephthalate masterbatch is prepared containing a pigment that has the characteristic of absorbing light in the near-infrared region, specifically wavelengths of 750 to 3,000 nm. In the present invention, for use in the polyethylene terephthalate melt spinning process, an ultraviolet absorber must be used that does not undergo thermal decomposition at temperatures of around 300°C and exhibits performance above a certain level due to minimal light-induced degradation even after prolonged exposure to sunlight. In the present invention, carbon black, graphite, carbon nanotubes, or carbon nanofibers may be used as carbon-based infrared absorbers. The carbon black has a particle size of 10 to 50 nm and a specific surface area of ​​90 to 110 m². 2A carbon nanotube with a diameter of / g may be used. The carbon nanotube may be a single-walled carbon nanotube (SWNT), a multi-walled carbon nanotube (MWNT), or a composite thereof, and the diameter of the carbon nanotube may be 1 nm to 50 nm.

[0039] In the present invention, the average particle size of the infrared absorber, i.e., the infrared absorbing particles, may be 1 to 50 nm, but is not limited thereto. If the average particle size of the infrared absorbing particles is less than 1 nm, dispersibility is reduced, resulting in a lower yield during the masterbatch manufacturing process, and uneven dispersion may occur, leading to a problem of non-uniform color in the manufactured polyester yarn. Additionally, if the average particle size of the infrared absorbing particles exceeds 50 nm, a large amount of yarn breakage may occur when manufacturing the polyester yarn.

[0040] It is preferable that the content of the above carbon-based infrared absorber be 30 ppm to 10,000 ppm based on the total weight of the high-strength infrared-absorbing polyester yarn.

[0041] The appropriate amount of infrared absorber added to the yarn varies depending on the performance of the type of infrared absorber used. The amount of infrared absorber can range from 30 ppm (corresponding to an infrared absorber content of 750 ppm in the masterbatch) to 10,000 ppm (corresponding to an infrared content of 250,000 ppm in the masterbatch) based on the total weight of the yarn. If the content of the infrared absorber is less than 30 ppm, infrared absorption is reduced and the desired characteristics cannot be obtained. If the content of the infrared absorber exceeds 10,000 ppm, it becomes difficult to manufacture the masterbatch chips and it is difficult to ensure uniform dispersion.

[0042] In the present invention, since the goal is to produce a high-strength polyester yarn with a strength of 8.0 g / d or higher, the intrinsic viscosity (IV) of the polyethylene terephthalate masterbatch containing an infrared absorber is 0.70 to 1.0 dl / g and solid-state polymerization is performed.

[0043] If the viscosity of the masterbatch is less than 0.7 dl / g, it is disadvantageous for developing yarn strength, and if the viscosity of the masterbatch is higher than 1.0 dl / g, non-uniformity in melting of the masterbatch occurs, leading to an increase in fluff and a deterioration in the appearance quality of the yarn.

[0044] It is preferable that the intrinsic viscosity of the polyethylene terephthalate chips, which are the main material for making yarn, be 1.0 to 1.2 dl / g. If the viscosity of the polyethylene terephthalate chips is less than 1.0 dl / g, it is disadvantageous for developing yarn strength, and if it is higher than 1.20 dl / g, uneven melting of the polyethylene terephthalate chips occurs, causing an increase in fluff and a problem with the appearance quality of the yarn deteriorating.

[0045] In order to adjust the intrinsic viscosity of the polyethylene terephthalate masterbatch containing the above-mentioned infrared absorber and the polyethylene terephthalate chip, which is the main material, to a desired level, each material is used by solid-state polymerization. The solid-state polymerization is carried out by drying at less than 1 torr at 120°C, surface crystallizing at 140°C, and then raising the temperature to 235°C and maintaining the temperature until the desired viscosity is achieved.

[0046] As described above, a molten polymer is prepared by mixing a polyethylene terephthalate masterbatch containing an infrared absorber with adjusted intrinsic viscosity with polyethylene terephthalate chips, which are the main material, in an appropriate ratio. This polymer is then extruded by passing it through a spinning nozzle, and subsequently rapidly cooled and solidified by passing it through a cooling zone. At this time, if necessary, a heating device of a certain length may be installed in the section of the hood, specifically the distance from directly below the nozzle to the starting point of the cooling zone. This zone is referred to as a delayed cooling zone or a heating zone, and it has a length of 150 to 450 mm and a temperature of 320 to 400°C (air contact surface temperature).

[0047] In the above cooling zone, depending on the method of blowing cooling air, open quenching, circular closed quenching, radial outflow quenching, and radial inflow quenching methods may be applied, but are not limited thereto. At this time, the temperature of the cooling air injected into the above cooling zone for rapid cooling is controlled to 20 to 50°C. Rapid cooling utilizing such a rapid temperature difference between the hood and the cooling zone is intended to increase the solidification point and spinning tension of the spun polymer, thereby increasing the orientation of the unoriented yarn and the formation of connecting chains between crystals.

[0048] Subsequently, the extruded yarn, which has solidified while passing through a cooling zone, can be oiled at a rate of 0.5 to 1.2 weight percent by applying an oiling device that applies an oil with excellent elongability and thermal efficiency while reducing the friction coefficient between individual yarns. The oiled extruded yarn is spun to form an unoriented yarn. Subsequently, the unoriented yarn is passed through a stretching roller for multi-stage stretching and wound at a speed of 2,500 to 4,500 m / min to produce a high-strength infrared-absorbing polyester yarn with an infrared-absorbing strength of 8.0 g / d or more.

[0049] When stretching an unoriented yarn, a yarn can be formed by stretching the yarn that has passed through the first stretching roller by passing it through a series of stretching rollers using a spin draw method. In the stretching process, the unoriented yarn can be stretched in multiple stages, and the temperature of each stretching roller is higher than the glass transition temperature of the unoriented yarn and lower than 95°C, but the temperature of the last stretching roller is preferably 200 to 250°C.

[0050] In addition, it is preferable that the total draw ratio of the formed yarn be 4.0 to 7.0. If the draw ratio is less than 4.0, productivity decreases and the strength of the yarn decreases, and if the draw ratio exceeds 7.0, crystallization of the oriented non-crystalline region increases, which reduces the drawability and causes yarn breakage, and the molecular chains of the amorphous region in the microstructure of the yarn break, which reduces the uniformity of the molecular chains and may actually reduce the tensile strength utilization rate, which is undesirable.

[0051] Another aspect of the present invention relates to webbing and seat belts manufactured from the high-strength infrared-absorbing polyester yarn of the present invention.

[0052] A webbing for a safety belt can be manufactured by weaving the high-strength infrared-absorbing polyester yarn of the present invention as the warp and a general polyester yarn as the weft. According to the present invention, the strength of the yarn is improved, allowing the number of warp threads used in weaving to be reduced, thereby making the safety belt webbing lighter. The webbing of the present invention is useful for use in safety belts, parachute harnesses and parachute lines, safety nets, trampolines, etc.

[0053] The present invention will be described in detail below through examples. However, these examples are intended to specifically explain the present invention, and the scope of the present invention is not limited to these examples.

[0054] Examples

[0055] Example 1

[0056] A polyethylene terephthalate masterbatch containing carbon black at a concentration of 750 ppm was prepared as an infrared absorber, and then solid-state polymerized to achieve an intrinsic viscosity of 0.90 dl / g. The polyethylene terephthalate chips, which are the main material, were solid-state polymerized to achieve an intrinsic viscosity of 1.05 dl / g and used. 96% of the polyethylene terephthalate chips and 4% of the polyethylene terephthalate masterbatch containing the infrared absorber were mixed and melted, and then spun using a spinneret with a 72-hole nozzle to achieve a carbon black concentration of 30 ppm in the yarn. After undergoing a drawing process under a draw ratio of 5.7 times, the yarn was wound at a speed of 3,150 m / min to produce a 1000 denier / 72 filament polyester yarn. Figure 1 shows a photograph taken with an IR camera of a seat belt webbing manufactured using the polyester yarn according to the present invention. Referring to FIG. 1, it can be seen that the image of the seatbelt webbing of the present invention captured with an infrared (IR) camera is distinguished from the area of ​​Comparative Example 1. Referring to FIG. 1, it can be seen that the infrared-absorbing polyester yarn of Example 1 appears as a darker gray or black color, and thus can be distinguished from the general yarn of Comparative Example 1, which does not absorb infrared light, thereby achieving an effect of improved identification.

[0057] Example 2

[0058] Polyethylene terephthalate masterbatch containing carbon black at a concentration of 125,000 ppm as an infrared absorber was prepared, and a polyester yarn was produced by carrying out the same procedure as in Example 1, except that the concentration of carbon black in the yarn was 5,000 ppm.

[0059] Example 3

[0060] Polyethylene terephthalate masterbatch containing carbon black at a concentration of 250,000 ppm as an infrared absorber was prepared, and a polyester yarn was produced in the same manner as in Example 1, except that the concentration of carbon black in the yarn was 10,000 ppm.

[0061] Example 4

[0062] Polyethylene terephthalate masterbatch containing SWNT at a concentration of 750 ppm as an infrared absorber was prepared, and a polyester yarn was manufactured in the same manner as in Example 1, except that the concentration of SWNT in the yarn was 30 ppm.

[0063] Example 5

[0064] Polyethylene terephthalate masterbatch containing SWNT at a concentration of 25,000 ppm as an infrared absorber was prepared, and a polyester yarn was produced in the same manner as in Example 1, except that the concentration of SWNT in the yarn was 1,000 ppm.

[0065] Example 6

[0066] Polyethylene terephthalate masterbatch containing MWNT at a concentration of 750 ppm as an infrared absorber was prepared, and a polyester yarn was produced in the same manner as in Example 1, except that the concentration of MWNT in the yarn was 30 ppm.

[0067] Example 7

[0068] Polyethylene terephthalate masterbatch containing MWNT at a concentration of 10,000 ppm as an infrared absorber was prepared, and a polyester yarn was produced in the same manner as in Example 1, except that the concentration of MWNT in the yarn was 400 ppm.

[0069] Example 8

[0070] Polyethylene terephthalate masterbatch containing MWNT at a concentration of 25,000 ppm as an infrared absorber was prepared, and a polyester yarn was produced in the same manner as in Example 1, except that the concentration of MWNT in the yarn was 1,000 ppm.

[0071] Example 9

[0072] Polyethylene terephthalate masterbatch containing graphite at a concentration of 750 ppm as an infrared absorber was prepared, and a polyester yarn was produced in the same manner as in Example 1, except that the concentration of graphite in the yarn was 30 ppm.

[0073] Example 10

[0074] Polyethylene terephthalate masterbatch containing graphite at a concentration of 12,500 ppm as an infrared absorber was prepared, and a polyester yarn was produced in the same manner as in Example 1, except that the concentration of graphite in the yarn was 500 ppm.

[0075] Example 11

[0076] Polyethylene terephthalate masterbatch containing graphite at a concentration of 25,000 ppm as an infrared absorber was prepared, and a polyester yarn was produced in the same manner as in Example 1, except that the concentration of graphite in the yarn was 1,000 ppm.

[0077] Test example

[0078] The intrinsic viscosity, yarn strength, infrared absorption performance, etc. of the infrared absorbing masterbatch and polyethylene terephthalate chips prepared in the examples and comparative examples were evaluated and are shown in Tables 1 and 2 below.

[0079] 1) Intrinsic viscosity (IV)

[0080] 0.1 g of the sample was added to a reagent mixed with phenol and 1,1,2,2-tetrachloroethanol in a 6:4 (weight ratio) ratio and dissolved for 90 minutes. The solution was then transferred to a Ubbelohde viscometer and maintained in a 30°C constant temperature bath for 10 minutes. The drop time of the solution was determined using the viscometer and an aspirator. The drop time of the solvent was determined in the same manner, and the RV and IV values ​​were calculated using the following mathematical formula.

[0081] RV = Sample drop seconds / Solvent drop seconds

[0082] IV = 1 / 4(RV- 1) / C + 3 / 4(In RV / C)

[0083] In the above formula, C represents the concentration of the sample in the solution (g / 100 ml).

[0084] 2) The spirit of the original master

[0085] After leaving the yarn in a constant temperature and humidity chamber under standard conditions, namely 25°C and 65%RH relative humidity, for 24 hours, the sample is measured using a tensile testing machine according to the ASTM D2256 method.

[0086] 3) Appearance of the yarn

[0087] During the winding of the yarn, it was checked with a strobo scope for 5 minutes, and if there was no fluff, it was judged to be good, and if fluff was found, it was judged to be defective.

[0088] 4) Lightfastness test of yarn

[0089] After winding the produced yarn densely into four layers on a plastic plate using a winder, a continuous 200-hour lightfastness test is conducted using a Weather-o-meter under conditions of a Xenon lamp, light irradiation intensity of 1.2 W / ㎡ (wavelength 420 nm), distance between the sample and the light source of 350 mm, black panel temperature of 63℃, and relative humidity of 30%.

[0090] 5) Reflectance of yarn (infrared absorption)

[0091] The reflectance of the yarn in the 300–3,000 nm range was measured using a UV-VIS-NIR Spectrophotometer (SHIMADZU, UV-3600 model), and it was determined that the lower the reflectance at 950 nm, the better the infrared absorption performance.

[0092] 6) Infrared camera image measurement

[0093] A yarn was installed in a dark room at a distance of 1 m from an infrared camera (IRON VTR8 model) and tilted backward at a 30° angle, and an image was captured, and the result is shown in Fig. 1. It can be determined that the darker the image appears in the infrared camera, the better the infrared absorption performance.

[0094] Classification Example 1 2 3 4 5 6 7 8 9 10 11 Infrared absorbing pigment Carbon Black SWN™ WNT Graphite yarn Internal infrared absorber concentration (ppm) 30 5000 10000 30 1000 30 400 1000 30 500 1000 Yarn strength (g / d) 9.3 28.5 18.0 79.1 48.7 69.0 58.7 98.3 89.0 98.8 28.6 1 Yarn appearance Good Good Good Good Good Good Good Good Good Good Yarn reflectance (950nm, %) 68.8 20.0 8.6 69.1 29.9 69.3 48.6 26.5 69.7 41.5 26.8 After lightfastness test (200h) Reflectance (950nm,%) 68.9 21.1 10.3 69.1 30.3 69.3 8.9 27.3 69.8 42.2 29.0

[0095]

[0096] Comparative Example 1

[0097] Polyester yarn was manufactured in the same manner as in Example 1, except that polyethylene terephthalate chips with an intrinsic viscosity of 1.05 dl / g were used without adding a polyethylene terephthalate masterbatch containing an infrared absorber.

[0098] Comparative Example 2

[0099] Polyethylene terephthalate masterbatch containing carbon black at a concentration of 500 ppm as an infrared absorber was prepared, and a polyester yarn was produced in the same manner as in Example 1, except that the carbon black concentration in the yarn was 20 ppm.

[0100] Comparative Example 3

[0101] Polyethylene terephthalate masterbatch containing carbon black at a concentration of 275,000 ppm as an infrared absorber was prepared, and a polyester yarn was produced in the same manner as in Example 1, except that the concentration of carbon black in the yarn was 11,000 ppm.

[0102] Comparative Example 4

[0103] Polyethylene terephthalate masterbatch containing SWNT at a concentration of 625 ppm as an infrared absorber was prepared, and a polyester yarn was manufactured in the same manner as in Example 1, except that the concentration of SWNT in the yarn was 25 ppm.

[0104] Comparative Example 5

[0105] Polyethylene terephthalate masterbatch containing MWNT at a concentration of 500 ppm as an infrared absorber was prepared, and a polyester yarn was produced in the same manner as in Example 1, except that the concentration of MWNT in the yarn was 20 ppm.

[0106] Comparative Example 6

[0107] Polyethylene terephthalate masterbatch containing graphite at a concentration of 625 ppm as an infrared absorber was prepared, and then solid-state polymerization was performed to produce a polyester yarn in the same manner as in Example 1, except that the concentration of graphite in the yarn was 25 ppm.

[0108] Comparative Example 7

[0109] Polyethylene terephthalate masterbatch containing metal phthalocyanine at a concentration of 2,500 ppm as an infrared absorber was prepared, and a polyester yarn was produced by carrying out the same procedure as in Example 1, except that the metal phthalocyanine concentration in the yarn was 100 ppm.

[0110] Comparative Example 8

[0111] Polyethylene terephthalate masterbatch containing tungsten oxide at a concentration of 2,000 ppm as an infrared absorber was prepared, and a polyester yarn was produced in the same manner as in Example 1, except that the concentration of tungsten oxide in the yarn was 80 ppm.

[0112] Comparative Example 9

[0113] Polyethylene terephthalate masterbatch containing copper pyrophosphate at a concentration of 2,000 ppm as an infrared absorber was prepared, and a polyester yarn was produced in the same manner as in Example 1, except that the copper pyrophosphate concentration in the yarn was 80 ppm.

[0114] Classification Comparison Example 1 2 3 4 5 6 7 8 9 Infrared absorbing pigment not added Carbon Black SWN™ WNT Graphite Metal Phthalocyanine Tungsten Oxide Copper Pyrophosphate Yarn Internal infrared absorber concentration (ppm) - 20 11,000 25 20 25 100 80 8 0 Yarn strength (g / d) 9.3 5 9.1 2 7.9 2 9.1 9 9.2 1 9.1 8 8.6 7 8.6 5 8.7 5 Yarn appearance Good Good Poor Good Good Good Poor Poor Yarn reflectance (950nm, %) 76.7 71.2 7.3 70.2 72.5 74.0 62.8 63.5 63.7 Reflectance after lightfastness test (200h) (980nm, %)76.771.29.270.272.571.169.370.372.2

[0115]

[0116] Referring to the contents of Tables 1 and 2 above, it can be confirmed that the yarns produced by the methods of Examples 1 to 11 of the present invention had a yarn strength of 8.0 g / d or higher and good appearance quality, and that the yarns had a low reflectance of 70% or less, indicating a characteristic of absorbing more light in the infrared region. In contrast, the yarn of Comparative Example 1 was a general polyester yarn without infrared absorption performance, so its reflectance was high at 76.7%, and the yarns of Comparative Examples 2, 4, 5, and 6 also showed a tendency to have high reflectances of 70% or higher. In the yarns of Comparative Examples 3, 7, 8, and 9, fluff was found, resulting in a problem of poor appearance quality.

[0117] The infrared-absorbing high-strength polyester yarn of the present invention can be used in vehicle seat belts. Recently developed vehicles are equipped with passenger protection devices that detect the occupant's belt wearing status or posture while seated to provide optimal restraint. By applying the infrared-absorbing polyester yarn of the present invention to a vehicle seat belt, accurate information regarding the belt wearing status of the occupant can be obtained, and accordingly, the performance can be improved to enable the seat belt's protective function to be exerted more effectively.

[0118] Although the present invention has been described above with reference to preferred embodiments, those skilled in the art will understand that various modifications and changes can be made to the invention without departing from the spirit and technical scope of the invention as set forth in the claims below. Accordingly, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification, but should be determined by the claims.

Claims

1. A high-strength infrared-absorbing polyester yarn comprising a carbon-based infrared absorber that absorbs light in the infrared region of wavelength 750 nm to 30,000 nm, composed of polyethylene terephthalate having an intrinsic viscosity of 0.7 to 1.0 dl / g, and having a strength of 8.0 g / d or more.

2. A high-strength infrared-absorbing polyester yarn according to claim 1, characterized in that the carbon-based infrared absorber is carbon black, graphite, carbon nanotubes, or carbon nanofibers.

3. In paragraph 2, the carbon black has a particle size of 10 to 50 nm and a specific surface area of ​​90 to 110 m² 2 High-strength infrared-absorbing polyester yarn characterized by having a strength of / g.

4. A high-intensity infrared-absorbing polyester yarn according to claim 2, wherein the carbon nanotube is a single-walled carbon nanotube (SWNT), a multi-walled carbon nanotube (MWNT), or a composite thereof, and the diameter of the carbon nanotube is 1 nm to 50 nm.

5. A high-strength infrared-absorbing polyester yarn according to claim 1, characterized in that the content of the carbon-based infrared absorber is 30 ppm to 10,000 ppm based on the total weight of the high-strength infrared-absorbing polyester yarn.

6. The high-intensity infrared-absorbing polyester yarn according to claim 1, characterized in that the yarn has a reflectance of 70% or less at a wavelength of 950 nm.

7. A step of preparing a polymer by mixing and melting a polyethylene terephthalate masterbatch having a viscosity (IV) of 0.7 to 1.0 dl / g containing a carbon-based infrared absorber that absorbs light in the infrared region of wavelength 750 nm to 30000 nm, and a polyethylene terephthalate chip having an intrinsic viscosity of 1.0 to 1.2 dl / g; A method for manufacturing a high-strength infrared-absorbing polyester yarn comprising the step of obtaining a polyester yarn by spinning the above polymer.

8. A method for manufacturing a high-strength infrared-absorbing polyester yarn, characterized in that, in claim 7, the carbon-based infrared absorber is carbon black, graphite, carbon nanotubes, or carbon nanofibers.

9. A method for manufacturing a high-intensity infrared-absorbing polyester yarn, characterized in that, in claim 8, the carbon nanotube is a single-walled carbon nanotube (SWNT), a multi-walled carbon nanotube (MWNT), or a composite thereof, and the diameter of the carbon nanotube is 1 nm to 50 nm.

10. A method for manufacturing a high-strength infrared-absorbing polyester yarn, characterized in that, in claim 7, the content of the carbon-based infrared absorber is 30 ppm to 10,000 ppm based on the total weight of the high-strength infrared-absorbing polyester yarn.

11. A safety belt manufactured from a high-strength infrared-absorbing polyester yarn according to any one of claims 1 to 6.

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