Flame-retardant polyester fiber having excellent dyeing property and method for preparing the same

Abstract

The present invention relates to a flame-retardant polyester fiber prepared using a titanium-based catalyst and an additive flame retardant, and to a flame-retardant polyester fiber having excellent dyeing properties with low acetaldehyde generation, excellent dyeing properties, and very low nozzle surface contamination, and a method for preparing the same.

Description

Technical Field

[0001] This invention relates to flame-retardant polyester fibers with excellent dyeability and their preparation methods. Background Technology

[0002] Polyesters possess excellent mechanical properties, chemical stability, and a high melting point, making them not only the most widely used synthetic fiber material but also a commercially important polymer used in various plastic products. To expand the applications of polyesters, numerous studies are underway, particularly attempts to improve properties and increase productivity by synthesizing polyesters with high polymerization degrees and low carboxyl content in shorter timeframes.

[0003] On the other hand, antimony compounds or germanium compounds are typically used on an industrial scale in the preparation of the aforementioned polyester resins. However, polyester resins prepared using antimony compounds as catalysts have adverse effects on safety, hygiene, and the environment due to their toxicity. While polyester resins prepared using germanium compounds as catalysts may be suitable in terms of transparency and safety, germanium compounds themselves are very expensive, resulting in unavoidable economic disadvantages. Therefore, there is an urgent need for a polycondensation catalyst that can replace them. For example, Korean Patent Publication No. 10-2016-0130764 discloses a flame-retardant polyester composition prepared using an antimony-based catalyst.

[0004] Therefore, many compounds have been proposed as alternatives to previously used antimony or germanium compounds as catalysts. Among them, titanium-based catalysts have attracted much attention due to their low cost and lack of safety and hygiene concerns. However, polyester resins prepared using titanium-based catalysts have a distinctive yellow color and poor thermal stability. Consequently, large amounts of acetaldehyde are generated as byproducts during decomposition reactions, such as polycondensation and melt molding, necessitating further investigation.

[0005] On the other hand, depending on the method of using the flame retardant in the aforementioned polyester resin, the flame retardant is classified into additive flame retardants and reactive flame retardants. Additive flame retardants refer to methods that improve the flame retardancy of polymers by physically adding flame retardants to polymer materials. For example, Korean Patent Publication No. 10-2004-00252101 discloses polyester fibers and nonwoven fabrics prepared by adding additive flame retardants to polyester resin.

[0006] The aforementioned additive flame retardants have the advantages of being easy to mix with polyester resins and having excellent flame retardant effects. However, polyester fibers prepared using these additive flame retardants have a high b-value (b*). Therefore, compared with CEPPA, which is the mainstream product in the existing flame retardant polyester market, there is a problem of poor color yield.

[0007] Furthermore, when excessive dye is applied under high-temperature dyeing conditions, the main chain of flame-retardant polyester resin undergoes thermal decomposition and hydrolysis, leading to a decrease in the strength and durability of flame-retardant polyester fibers, and may also result in a reduction in flame retardancy due to the shedding of flame retardant. Summary of the Invention

[0008] Technical issues

[0009] This invention was developed to solve the above-mentioned problems. The invention aims to prepare flame-retardant polyester fibers with excellent dyeability while using additive flame retardants, which contain very little or no antimony and / or cobalt components in the fibers.

[0010] Solution to the problem

[0011] The flame-retardant polyester fiber of the present invention, which has excellent dyeability, includes 10 ppm to 20 ppm of titanium (Ti) element in the fiber, and, based on phosphorus (P) element, includes 0.55 wt% to 0.75 wt% of an additive flame retardant represented by the following chemical formula 1 relative to 100 wt% of the fiber.

[0012] [Chemical Formula 1]

[0013]

[0014] In the above chemical formula 1, R is an alkylene group having 1 to 5 carbon atoms, n is an integer from 1 to 20, and m is an integer from 1 to 80.

[0015] As a preferred embodiment of the present invention, the weight-average molecular weight of the above-mentioned additive flame retardant can be 5,000 to 11,000.

[0016] As a preferred embodiment of the present invention, the above-mentioned titanium element can be derived from a titanium-based catalyst represented by the following chemical formula 2.

[0017] [Chemical Formula 2]

[0018]

[0019] In the above chemical formula 2, R 1 and R 2 Each is independently a straight-chain alkylene with 1 to 5 carbon atoms or a branched alkylene with 3 to 5 carbon atoms.

[0020] In a preferred embodiment of the present invention, when calculating the chromaticity coordinates of the above-mentioned fibers using a CIE standard light source and a standard observer, b* can be 1.0 to 2.5.

[0021] In a preferred embodiment of the present invention, the acetaldehyde production of the above-mentioned fiber, as measured by a gas detection tube, can be less than 400 ppb.

[0022] As a preferred embodiment of the present invention, the limiting oxygen index (LOI) of the above-mentioned fiber, measured according to the KS M 3032 method, can be 30% or more.

[0023] In a preferred embodiment of the present invention, the strength of the above-mentioned fiber can be from 3.6 g / de to 6.0 g / de.

[0024] As another object of the present invention, a method for preparing flame-retardant polyester fibers with excellent dyeability may include: step 1, reacting an acid component with a glycol component to obtain an esterification reactant; step 2, preparing a polymerization product by mixing and reacting a polymerization reactant comprising the above-mentioned esterification reactant, a heat stabilizer and a titanium-based catalyst; step 3, removing impurities from the above-mentioned polymerization product; step 4, preparing a flame-retardant polyester resin by mixing the polymerization product obtained in step 3 with an additive flame retardant represented by the following chemical formula 1; step 5, preparing a spun fabric by spinning the above-mentioned flame-retardant polyester resin; and step 6, preparing flame-retardant polyester fibers by stretching the above-mentioned spun fabric.

[0025] As a preferred embodiment of the present invention, based on the total weight of the flame-retardant polyester resin, the content of the additive flame retardant can be from 5.0% to 7.0% by weight.

[0026] [Chemical Formula 1]

[0027]

[0028] In the above chemical formula 1, R is an alkylene group having 1 to 5 carbon atoms, n is an integer from 1 to 20, and m is an integer from 1 to 80.

[0029] As a preferred embodiment of the present invention, based on the total weight of the above-mentioned polymerization reactants, the above-mentioned titanium-based catalyst may include 200 ppm to 400 ppm of a catalyst represented by the following chemical formula 2.

[0030] [Chemical Formula 2]

[0031]

[0032] In the above chemical formula 2, R 1 and R 2 Each is independently a straight-chain alkylene with 1 to 5 carbon atoms or a branched alkylene with 3 to 5 carbon atoms.

[0033] The effects of the invention

[0034] The flame-retardant polyester fiber of the present invention does not contain antimony compounds and / or cobalt compounds, thus it is human-friendly, has excellent dyeability and flame retardancy, and produces low acetaldehyde during the preparation of the flame-retardant polyester fiber, resulting in very low surface contamination of the spinning nozzle. Detailed Implementation

[0035] The preparation method of the flame-retardant polyester fiber with excellent dyeability of the present invention will be described in more detail below.

[0036] The method for preparing the above-mentioned flame-retardant polyester fiber may include: step 1, reacting an acid component with a glycol component to obtain an esterification reactant; step 2, preparing a polymerization product by mixing and reacting a polymerization reactant including the above-mentioned esterification reactant, a heat stabilizer, and a titanium-based catalyst; step 3, removing impurities from the above-mentioned polymerization product; step 4, preparing a flame-retardant polyester resin by mixing the polymerization product obtained in step 3 with an additive flame retardant; step 5, preparing a spun fabric by spinning the above-mentioned flame-retardant polyester resin; and step 6, preparing a flame-retardant polyester fiber by stretching the above-mentioned spun fabric.

[0037] Specifically, the acid component and the glycol component may be included in a molar ratio of 1:1.0 to 1:5.0, preferably 1:1.0 to 1:2.0. In this case, when the molar ratio of the glycol to the acid is less than 1.0, the acidity may increase excessively during polymerization, which may lead to the problem of promoting side reactions. When the molar ratio of the glycol to the acid is greater than 5.0, the degree of polymerization may be low.

[0038] On the other hand, the acid component may include at least one selected from terephthalic acid, aromatic polycarboxylic acids having 6 to 14 carbon atoms, aliphatic polycarboxylic acids having 2 to 14 carbon atoms, and sulfonic acid metal salts. Preferably, it may include at least one selected from terephthalic acid, aromatic polycarboxylic acids having 6 to 12 carbon atoms, aliphatic polycarboxylic acids having 3 to 14 carbon atoms, and sulfonic acid metal salts. Preferred examples of the acid component may include at least one selected from oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, octanoic acid, citric acid, pimelic acid, azelaic acid, sebacic acid, nonanoic acid, decanoic acid, dodecanoic acid, and hexadecanoic acid. More preferably, the acid component is terephthalic acid, which does not reduce the heat resistance of the polyester.

[0039] On the other hand, the aforementioned diol component may include components represented by the following chemical formula 3, and in addition, the aforementioned diol component may further include ethylene glycol, etc.

[0040] [Chemical Formula 3]

[0041]

[0042] In addition, the esterification reaction in step 1 can be carried out under esterification reaction conditions commonly used in the art. As a preferred example, it can be carried out at 200°C to 260°C at a speed of 40 rpm to 80 rpm for 150 minutes to 240 minutes. More preferably, it can be carried out at 210°C to 250°C at a speed of 50 rpm to 70 rpm for 180 minutes to 210 minutes.

[0043] In addition, as the aforementioned heat stabilizer, commonly used heat stabilizers in the art can be used. Preferably, one or more of the following can be used alone or in combination: trimethyl phosphate, triethyl phosphate, tributyl phosphate, tributoxyethyl phosphate, tricresyl phosphate, triaryl phosphate isopropylated, and hydroquinone bis(diphenyl phosphate).

[0044] In addition, based on the amount of phosphorus (P) in the total weight of the above-mentioned polymer reactants, the heat stabilizer may be included in the amount of 10 ppm to 30 ppm, preferably 15 ppm to 25 ppm.

[0045] Furthermore, the aforementioned polymerization reactants may also contain a complementary colorant. As the complementary colorant, a mixture of blue and red dyes can be used, which replace cobalt compounds that cause pulmonary interstitial fibrosis and are classified as human carcinogens, and are therefore harmless to humans. In addition, the aforementioned polymerization reactants may contain 1 ppm to 10 ppm, preferably 3 ppm to 7 ppm, of the aforementioned complementary colorant.

[0046] In addition, the above-mentioned titanium-based catalyst can be a titanium-based catalyst represented by the following chemical formula 2, preferably a titanium chelate catalyst represented by the following chemical formula 2.

[0047] [Chemical Formula 2]

[0048]

[0049] In the above chemical formula 2, R 1 and R 2 Each of the components can be a straight-chain alkylene with 1 to 5 carbon atoms or a branched alkylene with 3 to 5 carbon atoms. Preferably, each of the components can be a straight-chain alkylene with 1 to 3 carbon atoms or a branched alkylene with 3 to 4 carbon atoms.

[0050] Furthermore, the titanium-based catalyst represented by the above chemical formula 2 is stable even in the presence of water molecules. Therefore, even if the above titanium-based catalyst is added before the esterification reaction, which produces a large amount of water as a byproduct, it will not be deactivated. As a result, the esterification and polycondensation reactions can be carried out in a shorter time than before, and coloring can be suppressed. In addition, the above titanium-based catalyst has excellent polymerization reactivity even at lower polymerization temperatures. The number of carboxyl groups (-COOH) generated at the end of the polyester resin prepared with a higher degree of polymerization is reduced. Therefore, nozzle surface contamination caused by oligomers and monomers during the spinning process can be reduced, thereby reducing the number of times the nozzle surface needs to be cleaned, which improves production yield and reduces defect rate. In addition, it is possible to prepare human-friendly polymers with reduced acetaldehyde content.

[0051] Furthermore, based on the total weight of the aforementioned polymerization reactants, the titanium-based catalyst may include 200 ppm to 400 ppm, preferably 220 ppm to 380 ppm, and more preferably 250 ppm to 350 ppm. If less than 200 ppm of the titanium-based catalyst is included, the fiber's b* (b-value) will be too high, leading to poor dyeability and dye uptake, increased acetaldehyde production, and the inability to produce a human-friendly polymer. If more than 400 ppm of the titanium-based catalyst is included, there may be an excessive increase in carboxyl groups (-COOH) at the end of the flame-retardant polyester resin.

[0052] Secondly, the polymerization reaction in step 2 can be carried out by slowly reducing the pressure to a final pressure of 0.5 Torr while raising the temperature to 270°C to 290°C, preferably to 275°C to 285°C.

[0053] Secondly, the impurity removal in step 3 can be carried out by removing unreacted oligomers and byproducts under reduced pressure using a vacuum pump, and can be carried out for 20 to 40 minutes, preferably 25 to 35 minutes.

[0054] Secondly, the additive flame retardant in step 4 can be an additive flame retardant represented by the following chemical formula 1. The content of the additive flame retardant relative to the total weight of the flame-retardant polyester resin can be 5.0% to 7.0% by weight, preferably 5.2% to 6.8% by weight, and more preferably 5.5% to 6.5% by weight. If the content of the additive flame retardant is less than 5.0% by weight, the flame retardancy may be insufficient, or the flame retardant properties may be uneven. If the content of the additive flame retardant exceeds 7.0% by weight, the number of times the spinneret needs to be wiped will increase due to the high viscosity.

[0055] [Chemical Formula 1]

[0056]

[0057] In the above chemical formula 1, R is an alkylene group having 1 to 5 carbon atoms, preferably an alkylene group having 2 to 4 carbon atoms. Furthermore, n is an integer from 1 to 20, preferably an integer from 5 to 10. Additionally, m is an integer from 1 to 80, preferably an integer from 20 to 40.

[0058] Furthermore, the weight-average molecular weight of the aforementioned additive flame retardant can be from 4,000 to 11,000, preferably from 5,000 to 10,000, and more preferably from 6,000 to 8,000. If the weight-average molecular weight is less than 4,000, there may be a problem of reduced spinning operability due to low viscosity. If the weight-average molecular weight exceeds 11,000, the high viscosity of the polymer will cause pressure loss in the spinning process, resulting in uneven discharge and reduced fiber fineness uniformity.

[0059] Furthermore, the number of carboxyl groups (-COOH) in the flame-retardant polyester resin prepared in step 4, as determined by the PHOL method, can be between 33 and 40, preferably between 33 and 38. If the number of carboxyl groups exceeds 40, the process economy may suffer as the contamination level on the nozzle surface increases.

[0060] Furthermore, the intrinsic viscosity of the aforementioned flame-retardant polyester resin can be from 0.60 dl / g to 0.80 dl / g, preferably from 0.62 dl / g to 0.78 dl / g.

[0061] Secondly, spinning in step 5 can be performed through a spinneret (nozzle). Preferably, the spinneret can be O-shaped and can be spun at a spinning speed of 1000 mpm (meters / minute) to 1300 mpm at a temperature of 250°C to 290°C. Preferably, spinning can be spun at a spinning speed of 1050 mpm to 1250 mpm at a temperature of 260°C to 280°C.

[0062] Secondly, the stretching in step 6 can be performed at a stretching ratio of 2.5 to 4.1, preferably 2.8 to 3.8.

[0063] Furthermore, the flame-retardant polyester fiber prepared by the above method may contain 10 ppm to 20 ppm of titanium relative to the total weight of the fiber, preferably 12 ppm to 18 ppm of titanium, and more preferably 14 ppm to 16 ppm of titanium.

[0064] At this point, when the titanium content is below 10 ppm, the dyeability and dye uptake of the fiber may be poor, and the production of acetaldehyde may increase, making it impossible to produce fibers that are not friendly to human health. Furthermore, when the titanium content exceeds 20 ppm, the number of carboxyl groups at the ends of the prepared polyester resin may increase excessively, leading to increased contamination on the nozzle surface and potentially reducing the economic efficiency of the process.

[0065] Furthermore, the aforementioned titanium element can be used to derive titanium-based catalysts represented by the following chemical formula 2.

[0066] [Chemical Formula 2]

[0067]

[0068] In the above chemical formula 2, R 1 and R 2 Each of the components can be a straight-chain alkylene with 1 to 5 carbon atoms or a branched alkylene with 3 to 5 carbon atoms. Preferably, each of the components can be a straight-chain alkylene with 1 to 3 carbon atoms or a branched alkylene with 3 to 4 carbon atoms.

[0069] In addition, based on the amount of phosphorus (P) relative to the total weight of the fiber, the flame-retardant polyester fiber may include 0.55% to 0.75% by weight of an additive flame retardant, preferably 0.58% to 0.72% by weight of an additive flame retardant.

[0070] The physical properties of the above-mentioned flame-retardant polyester fibers are as follows.

[0071] First, the limiting oxygen index (LOI) of the above-mentioned fiber, as determined by the KS M 3032 method, can be 30% or more, preferably 30% to 40%, and more preferably 30% to 36%.

[0072] Furthermore, when calculating chromaticity coordinates using a CIE standard light source and a standard observer, the b* (b value) of the aforementioned fiber can be from 1.0 to 2.5, preferably from 1.0 to 2.1.

[0073] Furthermore, the strength of the aforementioned fibers can be from 3.6 g / de to 6.0 g / de, preferably from 4.0 g / de to 6.0 g / de, and more preferably from 4.4 g / de to 5.2 g / de. If the strength of the fibers is less than 3.6 g / de, the strength is too low and therefore may not be suitable for use as carpets or interior decoration fabrics.

[0074] In addition, the acetaldehyde production of the above-mentioned fiber, as measured by the gas detection tube, is less than 400 ppb, preferably 300 ppb to 400 ppb, and more preferably 310 ppb to 390 ppb.

[0075] Carpets or interior decoration fabrics shaped into a predetermined form can be manufactured by including the aforementioned flame-retardant polyester fibers. Preferred examples of the aforementioned interior decoration fabrics may include blinds, curtains, etc.

[0076] The present invention has been described above with reference to examples, but these are merely illustrative and not intended to limit the scope of the invention. Those skilled in the art will understand that various modifications and applications not illustrated above can be made to the invention without departing from its essential characteristics. For example, the various structural elements specifically represented in the examples of the invention can be modified. Furthermore, any differences related to such modifications and applications should be interpreted as falling within the scope of the invention as defined in the claims.

[0077] [Example]

[0078] Example 1: Preparation of flame-retardant polyester fibers

[0079] Terephthalic acid (TPA) is prepared as the acid component, and ethylene glycol (EG) is prepared as the glycol component.

[0080] In addition, the above-mentioned acid component and diol component were mixed in a molar ratio of 1:1.12 and subjected to esterification reaction at a temperature of 250°C and a pressure of 1140 Torr to prepare the esterified product.

[0081] Then, after transferring the esterification reactants to a polycondensation reactor, a polymerization product is prepared by reacting a mixture of the esterification reactants, a heat stabilizer, and a titanium-based catalyst represented by the following chemical formula 2-1. At this time, the polymerization is carried out by slowly reducing the pressure to a final pressure of 0.5 Torr while simultaneously raising the temperature to 280°C.

[0082] [Chemical Formula 2-1]

[0083]

[0084] In the above chemical formula 2-1, R 1 and R 2 Each is an independent straight-chain alkylene group having one carbon atom.

[0085] Furthermore, triethyl phosphate was used as the aforementioned heat stabilizer, and the aforementioned heat stabilizer was added such that, relative to the total weight of the aforementioned polymerization reactants, the content of the aforementioned heat stabilizer, based on phosphorus element, was 25 ppm.

[0086] In addition, 300 ppm of the above-mentioned titanium-based catalyst was added relative to the total weight of the above-mentioned polymerization reactants.

[0087] Furthermore, impurities from the above-mentioned polymer products can be removed by removing unreacted oligomers and byproducts under reduced pressure using a vacuum pump for 30 minutes.

[0088] Furthermore, after preparing a flame-retardant polyester resin by mixing 6% by weight of an additive flame retardant (weight-average molecular weight of 7000) represented by the following chemical formula 1-1 with the remaining amount of the above-mentioned polymer product, the flame-retardant polyester resin is spun to produce a spun fabric. At this time, the above spinning is performed at 275°C and a spinning speed of 1250 mpm (meters / minute).

[0089] [Chemical Formula 1-1]

[0090]

[0091] In the above chemical formula 1-1, R is a straight-chain alkylene group having 3 carbon atoms, n is an integer of 10, and m is an integer of 40.

[0092] Flame-retardant polyester fibers were then prepared by stretching the above-mentioned spun material at a stretch ratio of 3.3.

[0093] Examples 2 and 3: Preparation of flame-retardant polyester fibers

[0094] Except for the change in the content of the titanium-based catalyst as shown in Table 1 below, flame-retardant polyester fibers were prepared in the same manner as in Example 1 for Examples 2 to 3.

[0095] Examples 4 and 5: Preparation of flame-retardant polyester fibers

[0096] Except for the changes in the flame retardant content as shown in Table 1 below, flame retardant polyester fibers were prepared in the same manner as in Example 1 for Examples 4 to 5.

[0097] Examples 6 and 7: Preparation of flame-retardant polyester fibers

[0098] Except for changing the molecular weight of the flame retardant as shown in Table 1 below, flame-retardant polyester fibers were prepared in the same manner as in Example 1 for Examples 6 to 7.

[0099] Comparative Examples 1 to 2: Preparation of Polyester Fibers

[0100] Except for the change in the content of the titanium-based catalyst represented by chemical formula 2 as shown in Table 1 below, flame-retardant polyester fibers were prepared in the same manner as in Example 1 to Comparative Examples 1 to 2.

[0101] Comparative Examples 3 to 4: Preparation of Polyester Fibers

[0102] Except for the changes in the content of flame retardant as shown in Table 1 below, flame-retardant polyester fibers were prepared in the same manner as in Example 1 for Comparative Examples 3 to 4.

[0103] Comparative Examples 5 and 6: Preparation of Polyester Fibers

[0104] Except for changing the molecular weight of the flame retardant as shown in Table 1 below, flame-retardant polyester fibers were prepared in the same manner as in Example 1 for Comparative Examples 5 to 6.

[0105] Comparative Examples 7 to 10: Preparation of Polyester Fibers

[0106] Except for changing the type and content of the polymerization catalyst as shown in Table 1 below, flame-retardant polyester fibers were prepared in the same manner as in Example 1 for Comparative Examples 7 to 10.

[0107] Table 1

[0108]

[0109]

[0110] Experimental Example 1: Evaluation of the Physical Properties of Resin and Fiber

[0111] The physical properties of the flame-retardant polyester resins and flame-retardant polyester fibers prepared in Examples 1 to 7 and Comparative Examples 1 to 10 were evaluated using the following methods, and the results are shown in Tables 2 to 4 below.

[0112] (1) Determination of intrinsic viscosity

[0113] Polyester resin was melted in ortho-chlorophenol solvent at 110°C with a concentration of 2.0 g / 25 ml for 30 minutes, and then kept at a constant temperature of 25°C for 30 minutes. The intrinsic viscosity was measured using an automatic viscosity testing device connected to a CANON viscometer.

[0114] (2) Quantitative analysis of carboxyl terminus

[0115] Polyester resin was determined according to the PHOL method. Accurately weigh 0.1000 g to 0.1500 g of the polymer powder (crushed to 20 mesh) and place it in a test tube. Add 5 ml of benzyl alcohol and heat at 210 °C for 120 to 150 seconds while stirring with a micro-stirrer. Immediately after dissolution, immerse the test tube in water at 20 °C to 30 °C for 6 to 7 seconds to rapidly cool. Pour the contents into a 50 ml beaker containing 10 ml of chloroform, add another 5 ml of benzyl alcohol to the test tube, stir for 60 seconds, completely rinse off any remaining resin solution, and then add this to the beaker as the titrant. Using phenol red (0.1% benzyl alcohol solution) as an indicator, titrate the 0.1 N sodium hydroxide benzyl alcohol solution using a microsyringe (100 μl). Correct the titration result based on the blank test results for the titrant, and calculate the carboxyl content according to the following formula 1.

[0116] [Relation 1]

[0117]

[0118] Where f is the concentration coefficient of the 0.1N sodium hydroxide benzyl alcohol solution.

[0119] (3) Strength measurement

[0120] The strength of polyester fibers was determined using an automatic tensile testing machine (Textechno) at a speed of 20 mm / min and a clamping distance of 10 mm. The strength was obtained by dividing the load applied when the fiber was stretched by a constant force until it was cut by the fineness (denier).

[0121] (4) Number of wipes

[0122] During the fiber preparation process, the number of times the spinneret is wiped per day is calculated.

[0123] (5) Determination of b* (b value) and K / S value (color intensity)

[0124] The color of polyester fibers was analyzed using a colorimeter, and the b* and K / S values ​​were determined. The measurement method was based on spectrophotometry, employing a CIE standard illuminant and a standard observer to calculate the chromaticity coordinates.

[0125] (6) Acetaldehyde production

[0126] The prepared polyester fibers were placed in 3L Tedlar bags, filled with nitrogen to 2 / 3 capacity, and then placed in an oven with the internal temperature set to 65°C for 2 hours. After heating, the bags were left at room temperature for 30 minutes, and then further filled with nitrogen until the bags were completely filled. The amount of acetaldehyde produced was then measured using a gas detection tube manufactured by Gastec.

[0127] (7) Limiting Oxygen Index (LOI) Measurement

[0128] The limiting oxygen index (LOI) of polyester fibers was determined according to the KS M 3032 method.

[0129] (8) Spinning operability (number of drops)

[0130] The number of drops per hour is measured during the spinning process.

[0131] (9) Evaluation of cross-sectional uniformity

[0132] When expressing the diameter variation rate among individual yarns of polyester fiber as a percentage, if the above variation rate is less than 5%, it is evaluated as "good"; if the above variation rate is 5% to 8%, it is evaluated as "average"; and if the above variation rate exceeds 8%, it is evaluated as "poor".

[0133] Table 2

[0134]

[0135] Table 3

[0136]

[0137]

[0138] Table 4

[0139]

[0140] Referring to Tables 2 to 4 above, it can be confirmed that the flame-retardant polyester fibers prepared in Examples 1 to 7 have excellent physical properties. On the other hand, Comparative Example 1, with a residual titanium content of 7 ppm, has a higher b* (b value) compared to Example 2, with a residual titanium content of 10 ppm. Therefore, the fibers have poor dyeability, poor dyeing rate (color strength, K / S), and high acetaldehyde production, posing a problem of harm to human health.

[0141] In addition, compared with Example 3, where the residual titanium content in the fiber was 20 ppm, Comparative Example 2, where the residual titanium content in the fiber was 23 ppm, generated excessive carboxyl groups (COOH groups) at the end of the flame-retardant polyester resin, resulting in a significant increase in the surface contamination of the nozzle and thus a problem of shortened wiping cycle.

[0142] Furthermore, compared with Example 4, which contained 5.0% by weight of the added flame retardant, Comparative Example 3, which contained 4.5% by weight of the added flame retardant, exhibited significantly poor flame retardancy.

[0143] In addition, compared with Example 5, which contained 7.0% by weight of the additive flame retardant, Comparative Example 4, which contained 7.5% by weight of the additive flame retardant, showed increased nozzle surface contamination, resulting in a significantly shorter wiping cycle.

[0144] Furthermore, compared with the flame-retardant polyester fiber prepared using an additive flame retardant with a weight-average molecular weight of 5000 (Example 6), the fiber prepared using an additive flame retardant with a weight-average molecular weight of 4000 has low viscosity, resulting in poor fiber strength and increased number of drips during the spinning process, leading to poor fiber quality.

[0145] In addition, compared with flame-retardant polyester fiber with a weight average molecular weight of 10,000 (Example 7), the fiber of Comparative Example 6, which was prepared using an additive flame retardant with a weight average molecular weight of 12,000, has high viscosity and therefore has the problem of uneven cross-section.

[0146] Furthermore, compared to Example 1, which used a compound represented by Chemical Formula 2-1 as a titanium-based catalyst, Comparative Example 7, which used titanium acetylacetonate instead of the compound represented by Chemical Formula 2-1 as a titanium-based catalyst, had an excessive number of carboxyl groups (COOH groups) at the resin end, resulting in increased contamination on the nozzle surface and a shorter wiping cycle. Additionally, compared to Example 1, Comparative Example 7 exhibited poor dyeing properties and dye uptake, and produced a higher amount of acetaldehyde, resulting in relatively poor physical properties.

[0147] Furthermore, compared to Example 1, which used a compound represented by Chemical Formula 2-1 as a titanium-based catalyst, Comparative Examples 8 to 10, which used an antimony-based catalyst as a polymerization catalyst, showed a significant increase in the number of carboxyl (COOH) groups. This resulted in increased nozzle surface contamination, a shorter wiping cycle, significantly higher acetaldehyde production, and poorer dyeability and dyeing rate. Therefore, it can be concluded that the fibers of Comparative Examples 8 to 10 have inferior physical properties compared to fibers prepared using a titanium-based catalyst.

[0148] Those skilled in the art can readily implement simple variations or modifications of the present invention, and such variations or modifications are all within the scope of protection of the present invention.

Claims

1. A flame-retardant polyester fiber having excellent dyeing property, the polyester fiber being produced by spinning a flame-retardant polyester resin prepared by mixing a 5.0 to 7.0 wt% additive flame retardant represented by the following Chemical Formula 1 and a polymerization product, spinning the flame-retardant polyester resin to produce a spun material, and then drawing the spun material, characterized in that: the polymerization product is produced by polymerization reaction of a polymerization reactant including an esterification reactant obtained by reacting an acid component with a diol component, a heat stabilizer, and a titanium-based catalyst represented by the following Chemical Formula 2, the polymerization reactant includes 200 to 400 ppm of the titanium-based catalyst with respect to the total weight of the polymerization reactant, the additive flame retardant has a weight average molecular weight of 5,000 to 11,000, the polyester fiber includes 10 to 20 ppm of titanium element, the polyester fiber has an limiting oxygen index of 30% or more according to the KS M 3032 method, the polyester fiber has a strength of 3.6 to 6.0 g / denier, and the acetaldehyde generation amount of the fiber is 400 ppb or less as measured by a gas detection tube, the Chemical Formula 1 is: [Chemical Formula 1] R-(O)n-H (1) (wherein R is an alkylene group having 1 to 5 carbon atoms, n is an integer of 1 to 20, and m is an integer of 1 to 80), and the Chemical Formula 2 is: [Chemical Formula 2] Ti(OR)4 (2) (wherein R is an alkyl group having 1 to 5 carbon atoms).

1. A flame-retardant polyester fiber having excellent dyeing property, the polyester fiber being produced by spinning a flame-retardant polyester resin prepared by mixing a 5.0 to 7.0 wt% additive flame retardant represented by the following Chemical Formula 1 and a polymerization product, spinning the flame-retardant polyester resin to produce a spun material, and then drawing the spun material, characterized in that: the polymerization product is produced by polymerization reaction of a polymerization reactant including an esterification reactant obtained by reacting an acid component with a diol component, a heat stabilizer, and a titanium-based catalyst represented by the following Chemical Formula 2, the polymerization reactant includes 200 to 400 ppm of the titanium-based catalyst with respect to the total weight of the polymerization reactant, the additive flame retardant has a weight average molecular weight of 5,000 to 11,000, the polyester fiber includes 10 to 20 ppm of titanium element, the polyester fiber has an limiting oxygen index of 30% or more according to the KS M 3032 method, the polyester fiber has a strength of 3.6 to 6.0 g / denier, and the acetaldehyde generation amount of the fiber is 400 ppb or less as measured by a gas detection tube, the Chemical Formula 1 is: [Chemical Formula 1] R-(O)n-H (1) (wherein R is an alkylene group having 1 to 5 carbon atoms, n is an integer of 1 to 20, and m is an integer of 1 to 80), and the Chemical Formula 2 is: [Chemical Formula 2] Ti(OR)4 (2) (wherein R is an alkyl group having 1 to 5 carbon atoms).

1. A flame-retardant polyester fiber having excellent dyeing property, the polyester fiber being produced by spinning a flame-retardant polyester resin prepared by mixing a 5.0 to 7.0 wt% additive flame retardant represented by the following Chemical Formula 1 and a polymerization product, spinning the flame-retardant polyester resin to produce a spun material, and then drawing the spun material, characterized in that: the polymerization product is produced by polymerization reaction of a polymerization reactant including an esterification reactant obtained by reacting an acid component with a diol component, a heat stabilizer, and a titanium-based catalyst represented by the following Chemical Formula 2, the polymerization reactant includes 200 to 400 ppm of the titanium-based catalyst with respect to the total weight of the polymerization reactant, the additive flame retardant has a weight average molecular weight of 5,000 to 11,000, the polyester fiber includes 10 to 20 ppm of titanium element, the polyester fiber has an limiting oxygen index of 30% or more according to the KS M 3032 method, the polyester fiber has a strength of 3.6 to 6.0 g / denier, and the acetaldehyde generation amount of the fiber is 400 ppb or less as measured by a gas detection tube, the Chemical Formula 1 is: [Chemical Formula 1] R-(O)n-H (1) (wherein R is an alkylene group having 1 to 5 carbon atoms, n is an integer of 1 to 20, and m is an integer of 1 to 80), and the Chemical Formula 2 is: [Chemical Formula 2] Ti(OR)4 (2) (wherein R is an alkyl group having 1 to 5 carbon atoms).

1. A flame-retardant polyester fiber having excellent dyeing property, the polyester fiber being produced by spinning a flame-retardant polyester resin prepared by mixing a 5.0 to 7.0 wt% additive flame retardant represented by the following Chemical Formula 1 and a polymerization product, spinning the flame-retardant polyester resin to produce a spun material, and then drawing the spun material, characterized in that: the polymerization product is produced by polymerization reaction of a polymerization reactant including an esterification reactant obtained by reacting an acid component with a diol component, a heat stabilizer, and a titanium-based catalyst represented by the following Chemical Formula 2, the polymerization reactant includes 200 to 400 ppm of the titanium-based catalyst with respect to the total weight of the polymerization reactant, the additive flame retardant has a weight average molecular weight of 5,000 to 11,000, the polyester fiber includes 10 to 20 ppm of titanium element, the polyester fiber has an limiting oxygen index of 30% or more according to the KS M 3032 method, the polyester fiber has a strength of 3.6 to 6.0 g / denier, and the acetaldehyde generation amount of the fiber is 400 ppb or less as measured by a gas detection tube, the Chemical Formula 1 is: [Chemical Formula 1] R-(O)n-H (1) (wherein R is an alkylene group having 1 to 5 carbon atoms, n is an integer of 1 to 20, and m is an integer of 1 to 80), and the Chemical Formula 2 is: [Chemical Formula 2] Ti(OR)4 (2) (wherein R is an alkyl group having 1 to 5 carbon atoms). ​ ​ ​ ​ ​ ​ In the above Chemical Formula 2, R 1 and R 2 each independently is a linear alkylene group having 1 to 5 carbon atoms or a branched alkylene group having 3 to 5 carbon atoms.

2. The flame-retardant polyester fiber having excellent dyeing properties according to claim 1, characterized by, b is from 1.0 to 2.

5.

3. A process for producing a flame-retardant polyester fiber having excellent dyeing property, characterized by, ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ In the above Chemical Formula 2, R 1 and R 2 each independently is a linear alkylene group having 1 to 5 carbon atoms or a branched alkylene group having 3 to 5 carbon atoms.

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