Thermally adhesive composite fiber, method for preparing the same, fiber assembly and nonwoven fabric containing the same

Abstract

The present invention relates to a thermal adhesive composite fiber, a method for preparing the same, a fiber assembly and a nonwoven fabric comprising the same. More specifically, the present invention relates to a thermal adhesive composite fiber having a low process defect rate, excellent productivity, excellent adhesiveness and elastic recovery rate, and a method for preparing the same, and also relates to a fiber assembly and a nonwoven fabric that are suitable for use in materials that come into contact with the human body because they are harmless to the human body.

Description

Technical Field

[0001] The present invention relates to a thermal adhesive composite fiber, a method for preparing the same, a fiber assembly and a nonwoven fabric comprising the same. More specifically, the present invention relates to a thermal adhesive composite fiber having a low process defect rate, excellent productivity, excellent adhesiveness and elastic recovery rate, and a method for preparing the same, and also relates to a fiber assembly and a nonwoven fabric that are suitable for use in materials that come into contact with the human body because they are harmless to the human body. Background Art

[0002] Generally, polyurethane foam is a foam prepared by mixing isocyanate and polyol with a blowing agent, a catalyst, etc., and simultaneously performing a foaming reaction and a polymerization reaction. Since the polyurethane foam is lightweight, has excellent thermal insulation, electrical insulation, chemical resistance, resilience and durability, it is widely used as an elastic material in the field of cushioning materials. However, polyurethane foam has problems such as yellowing and odor, environmental hazards and deterioration of physical properties.

[0003] On the other hand, in addition to polyurethane foam, fiber aggregates welded with environmentally friendly heat-adhesive fibers that are harmless to the human body are also used as elastic materials. Elastomers used as fiber aggregate materials are used for packaging containers, automotive interior materials, elastic fibers and other purposes due to their unique elasticity. In addition, unlike rubber materials that cannot be recycled, these elastomers are easy to recycle, so their demand is greatly increasing. In particular, thermoplastic polyester copolymers are used as fiber aggregate materials due to their excellent elasticity.

[0004] Thermoplastic elastomer (TPE) is a polymer that has two different properties at the same time, that is, a polymer that has both thermoplasticity that can be reformed when heated and elasticity as an elastomer of a rubbery polymer. Thermoplastic elastomer is a block copolymer, generally composed of a hard segment block that exhibits thermoplastic properties and a soft segment block that exhibits elasticity, thereby exhibiting two different properties at the same time.

[0005] These thermoplastic elastomers are prepared by copolymerizing acid components such as terephthalic acid, dimethyl terephthalate, isophthalic acid and dimethyl isophthalate with diol components such as poly(tetramethylene ether) glycol, butanediol, polyethylene glycol and ethylene glycol. However, when preparing low-melting thermoplastic elastomers by such polymerization methods, there are problems such as the need for equipment for storing and injecting butanediol and equipment for recovering by-products such as tetrahydrofuran. In particular, tetrahydrofuran is a highly dangerous substance with toxicity and explosiveness, and its safety management is difficult.

[0006] Furthermore, although the demand for these thermoplastic elastomers is rising, the market size is relatively small, so there is a disadvantage of increased fixed costs when producing polymers by a polymerization method, resulting in increased costs. Summary of the invention

[0007] Technical issues

[0008] The present invention has been made to solve the above-mentioned problems, and the problem to be solved by the present invention is to provide a thermally adhesive composite fiber which is excellent in thermal adhesiveness and elastic recovery rate and can reduce the cost, and a fiber assembly and nonwoven fabric including the same.

[0009] Another problem to be solved by the present invention is to provide a method for producing a thermally adhesive composite fiber with a low process defect rate and excellent productivity.

[0010] Means of solving the problem

[0011] In order to solve the above-mentioned problems, the present invention provides a thermally adhesive composite fiber, which is obtained by conjugating and spinning a thermoplastic polyester elastomer resin and a polyester resin, wherein the thermoplastic polyester elastomer resin is a block copolymer having a melting point of 110°C to 180°C and including a soft segment having a structure represented by the following Chemical Formula 1 in an amount of 5 mol % to 25 mol %, and the polyester resin has a melting point of 230°C to 280°C.

[0012] [Chemical formula 1]

[0013]

[0014] In the above chemical formula 1, R represents C 3 To C 5 Alkylene.

[0015] In a preferred embodiment of the present invention, the thermoplastic polyester elastomer resin may include a block copolymer formed by an ester exchange reaction of resin A and resin B, wherein the resin A includes a compound represented by the following chemical formula 2, and the resin B includes at least one of a compound represented by the following chemical formula 3 and a compound represented by the following chemical formula 4.

[0016] [Chemical formula 2]

[0017]

[0018] [Chemical formula 3]

[0019]

[0020] [Chemical formula 4]

[0021]

[0022] In the above Chemical Formulae 2 to 4, P 1 and P 2 Each independently R 1 and R 2 Each independently is C 3 To C 5 Alkylene, R 3 To R 5 Each independently is C 1 To C 3 Alkylene, R 6 C 4 H 8 , n is a rational number from 5 to 45, x is a rational number from 25 to 90, y is a rational number from 10 to 75, a and c are each independently a rational number from 55 to 80, and b and d are each independently a rational number from 20 to 45.

[0023] In a preferred embodiment of the present invention, the thermoplastic polyester elastomer resin may be formed by reacting the resin A and the resin B at a weight ratio of 7:3 to 2:8.

[0024] In a preferred embodiment of the present invention, the melting point of the resin A may be 140°C to 175°C, and the softening point of the resin B may be 110°C to 150°C.

[0025] In a preferred embodiment of the present invention, the elastic recovery rate of the thermoplastic polyester elastomer resin measured according to the ASTM D638 standard test method may be 80% to 99%.

[0026] In order to solve the above-mentioned problems, the present invention provides a fiber assembly including the above-mentioned thermal adhesive conjugate fiber.

[0027] In a preferred embodiment of the present invention, the fiber assembly may further include polyethylene terephthalate (PET) fibers.

[0028] In a preferred embodiment of the present invention, the detected concentrations of antimony (Sb) and cobalt (Co) as heavy metals in the fiber assembly may be independently 0.1 ppm to 10 ppm.

[0029] In order to solve the above-mentioned problems, the present invention provides a nonwoven fabric including the above-mentioned fiber assembly.

[0030] In addition, in order to solve the above-mentioned problems, the present invention provides a method for preparing a thermally adhesive composite fiber, and the above-mentioned method for preparing a thermally adhesive composite fiber comprises: step (1), copolymerizing a resin A including a compound represented by the following chemical formula 2 and a resin B including a compound represented by the following chemical formula 3 and at least one of a compound represented by the following chemical formula 4 through an ester exchange reaction to synthesize a thermoplastic polyester elastomer resin; step (2), conjugating and spinning the above-mentioned thermoplastic polyester elastomer resin and a polyester resin having a melting point of 230°C to 280°C.

[0031] [Chemical formula 2]

[0032]

[0033] [Chemical formula 3]

[0034]

[0035] [Chemical formula 4]

[0036]

[0037] In the above Chemical Formulae 2 to 4, P 1 and P 2 Each independently R 1 and R 2 Each independently is C 3 To C 5 Alkylene, R 3 To R 5 Each independently is C 1 To C 3 Alkylene, R 6 C 4 H 8 , n is a rational number from 5 to 45, x is a rational number from 25 to 90, y is a rational number from 10 to 75, a and c are each independently a rational number from 55 to 80, and b and d are each independently a rational number from 20 to 45.

[0038] Effects of the Invention

[0039] The thermally adhesive composite fiber, fiber assembly and nonwoven fabric thereof according to the present invention have excellent thermal adhesiveness and elastic recovery rate and low harm to the human body. Therefore, they have the advantage of being easily used in materials that come into direct contact with the human body, such as bedding or automobile interior materials.

[0040] In addition, according to the preparation method of the thermally adhesive composite fiber of the present invention, no by-products are generated during the preparation process, the process is easy to manage, the process is simplified, and the productivity is high. Even in small-scale production, the increase in fixed costs can be minimized, thereby reducing the manufacturing cost of the thermally adhesive composite fiber.

[0041] The problem to be solved by the present invention is to provide a thermal adhesive composite fiber having excellent thermal adhesiveness and elastic recovery rate and capable of reducing costs BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 FIG. 1 is a diagram schematically showing a cross section of a thermally adhesive composite fiber according to an embodiment of the present invention.

[0043] Figure 2 The figure schematically shows a cross section of a thermal adhesive composite fiber according to another embodiment of the present invention. DETAILED DESCRIPTION

[0044] Best Mode for Carrying Out the Invention

[0045] Hereinafter, the present invention will be described in more detail with reference to embodiments and accompanying drawings.

[0046] As described above, the existing thermal adhesive composite fiber generates a large amount of by-products during the manufacturing process, and a separate device for processing the by-products is required. Moreover, these by-products are difficult to process, and there are problems such as increased manufacturing costs. Therefore, the inventors of the present invention provide a thermal adhesive composite fiber in an attempt to solve the above-mentioned problems. The thermal adhesive composite fiber is obtained by conjugating a thermoplastic polyester elastomer resin and a polyester resin, wherein the thermoplastic polyester elastomer resin has a melting point of 110° C. to 180° C. and includes a soft segment having a structure represented by the following Chemical Formula 1 at a content of 5 mol % to 25 mol %, and the polyester resin has a melting point of 230° C. to 280° C.

[0047] [Chemical formula 1]

[0048]

[0049] In the above chemical formula 1, R represents C 3 To C 5 Alkylene.

[0050] Preferably, the above n can be a rational number ranging from 5 to 45.

[0051] Here, including the soft segment in an amount of 5 to 25 mol % in the thermoplastic polyester elastomer resin means that the content of the soft segment repeating unit including the structure represented by the above Chemical Formula 1 is 5 to 25 mol % relative to the total content of the resin.

[0052] In the present invention, the above-mentioned soft segment is included in the above-mentioned thermoplastic polyester elastomer resin in an amount of 5 mol% to 25 mol% by polymer blending, so that the above-mentioned thermoplastic polyester elastomer resin exhibits excellent thermal adhesiveness and elasticity due to the thermoplasticity of the resin, and the polyester elastomer has a dry surface property while having a sticky surface property, thereby having improved processability. In addition, when it is manufactured by conjugation spinning between a low-melting point polyester having a melting point of 230° C. to 280° C. and the above-mentioned polyester elastomer resin, there is an advantage that the generation of by-products can be minimized and the manufacturing cost can be reduced.

[0053] More preferably, the thermoplastic polyester-based elastomer may include the soft segment in an amount of 10 mol % to 20 mol %.

[0054] If the content of the soft segment in the thermoplastic polyester elastomer resin is less than 5 mol%, there may be a problem of not being able to exhibit sufficient elasticity. On the contrary, if the content of the soft segment exceeds 25 mol%, there may be a problem of reduced processability due to friction on the elastomer surface.

[0055] Hereinafter, each component included in the above-mentioned thermal adhesive conjugate fiber will be described in detail one by one.

[0056] The heat-adhesive composite fiber of the present invention is prepared by blending and spinning a thermoplastic polyester elastomer resin and a low-melting-point polyester resin, wherein the thermoplastic polyester elastomer resin has a melting point of 110°C to 180°C.

[0057] Preferably, the thermoplastic polyester-based elastomer resin may have a melting point of 120°C to 165°C.

[0058] If the melting point of the above-mentioned thermoplastic polyester elastomer resin is lower than 110°C, the mechanical properties such as welding property, heat resistance, hardness, tensile strength and elastic modulus during spinning may be reduced. Moreover, if the melting point of the above-mentioned thermoplastic polyester elastomer resin exceeds 180°C, the thermal bonding performance may be reduced or the temperature of the manufacturing process may be increased during the manufacturing process of the fiber assembly.

[0059] The thermoplastic polyester elastomer resin may include a block copolymer formed by an ester exchange reaction of resin A and resin B, wherein the resin A includes a compound represented by the following Chemical Formula 2, and the resin B includes at least one of a compound represented by the following Chemical Formula 3 and a compound represented by the following Chemical Formula 4.

[0060] [Chemical formula 2]

[0061]

[0062] [Chemical formula 3]

[0063]

[0064] [Chemical formula 4]

[0065]

[0066] In the above Chemical Formulae 2 to 4, P 1 and P 2 Each independently expresses

[0067]

[0068] And, R 1 and R 2 Can be expressed independently of C 3 To C 6 Preferably, R 1 Can be C 3 To C 4 Alkylene, R 2 Can be C 4 Alkylene.

[0069] And, R 3 To R 5 Can be independently C 1 To C 3 Preferably, R 3 , R 4 and R 5 Can be C 2 Alkylene.

[0070] In addition, R 6 Can be C 4 H 8 ,n can be a rational number from 5 to 45.

[0071] x may be a rational number ranging from 25 to 90. Preferably, x may be ranging from 50 to 80.

[0072] y may be a rational number from 10 to 75. Preferably, y may be from 20 to 50, and preferably, the ratio of x to y may be from 2:1 to 5:1.

[0073] The segment repeated x times has hardness, and the segment repeated y times has softness. When x becomes larger in the ratio of x to y of 5:1, the molar ratio of the segment having hardness becomes too large, resulting in a problem of insufficient elasticity. On the contrary, when y becomes larger in the ratio of x to y of 2:1, the molar ratio of the segment having softness becomes too large, so workability may be deteriorated.

[0074] a and c may each independently be a rational number of 55 to 80, preferably, each independently be a rational number of 55 to 70.

[0075] b and d may each independently be a rational number of 20 to 45, preferably, each independently be 30 to 45.

[0076] In addition, the ratio of a to b and the ratio of c to d may preferably be 1: 1 to 3: 1. The segment repeating the above a times and the segment repeating b times have high crystallinity, and the segment repeating c times and the segment repeating d times have low crystallinity. If the ratio of a to c is greater than 1: 1 compared to the ratio of b to d, the molar ratio of the segment having high crystallinity may be excessively increased, resulting in an increase in the melting point.

[0077] In addition, the resin A may preferably be an elastic polyester elastomer having a melting point of 140 to 175° C. If the melting point of the resin A is less than 140° C., heat resistance may be reduced, and if the melting point exceeds 175° C., thermal bonding at high temperature may be required.

[0078] In addition, the resin B may preferably be a low melting point polyester resin having a softening point of 110° C. to 150° C. If the softening point of the resin B is lower than 110° C., heat resistance may be a problem, and if the softening point of the resin B exceeds 150° C., thermal bonding at a high temperature may be required.

[0079] The thermoplastic polyester elastomer resin may be a block copolymer formed by reacting the resin A and the resin B at a weight ratio of 7:3 to 2:8. Preferably, the weight ratio of the resin A to the resin B may be 60:40 to 30:70, more preferably 50:50 to 40:60.

[0080] If the ratio of resin A is greater in the weight ratio of resin A to resin B of 7:3, there is a problem of increased manufacturing cost. On the contrary, if the ratio of resin A is smaller in the weight ratio of resin A to resin B of 2:8, there may be a problem that the elasticity of the thermal adhesive composite fiber cannot be fully expressed.

[0081] According to a preferred embodiment, the above-mentioned resin A and resin B can be connected by a chain extender including at least one selected from the group consisting of pyromellitic dianhydride, trimellitic dianhydride, carbonyl bis-(1-caprolactam), diepoxidebisphenol A-diglycidyl ether, diepoxide ibsphenol F-diglycidyl ether, and epoxide, but is not limited thereto.

[0082] The chain extender is added to adjust the melting point and improve the copolymerization efficiency in the transesterification step between resin A and resin B, and can be selected from compounds that react with the terminal carboxyl group or hydroxyl group of the resins represented by the above Chemical Formulas 2 to 4.

[0083] Preferably, the content of the chain extender may be 0.1 to 10 parts by weight relative to 100 parts by weight of the thermoplastic polyester elastomer resin. Preferably, the content of the chain extender may be 0.1 to 3 parts by weight, and more preferably, in terms of minimizing the transesterification reaction time and the gelation of the polymer, it can be obtained according to the following relational formula 1.

[0084] [Equation 1]

[0085] Chain extender content (weight %) = (weight average molecular weight of chain extender (M w )×the carboxyl terminal content of the reaction extrusion target resin)÷(2×10 4 )

[0086] If the content of the above-mentioned chain extender is less than 0.1 parts by weight, the ester exchange reaction between resin A and resin B may be too long, resulting in a decrease in productivity. If the content of the above-mentioned chain extender is greater than 10 parts by weight, the chain is excessively elongated, causing polymer gelation, resulting in poor spinning operability and deterioration of the physical properties of the thermally adhesive composite fiber.

[0087] In addition, the thermoplastic polyester elastomer resin may include 0.1 to 3 parts by weight of an antioxidant relative to 100 parts by weight of the thermoplastic polyester elastomer resin to prevent thermal decomposition and aging. The antioxidant may be at least one selected from the group consisting of hindered phenolic antioxidants, diphenylamine antioxidants, metal complex antioxidants, and hindered amine light stabilizers. Preferably, tetramethylene (3,5-di-tert-butyl-4-hydroxyphenyl) propionate or tris (2,4-di-tert-butylphenyl) phosphite may be used alone, or tetramethylene (3,5-di-tert-butyl-4-hydroxyphenyl) propionate and tris (2,4-di-tert-butylphenyl) phosphite may be used in combination.

[0088] If the content of the antioxidant is less than 0.1 parts by weight, the effect of adding the antioxidant may be insufficient. On the contrary, if the content of the antioxidant exceeds 3 parts by weight, the mechanical properties of the thermal adhesive composite fiber may be deteriorated.

[0089] In addition, the intrinsic viscosity of the thermoplastic elastomer resin may preferably be 0.8 dl / g or more, more preferably 0.9 dl / g to 1.5 dl / g, and further preferably 1.0 dl / g to 1.3 dl / g. If the intrinsic viscosity is less than 0.8 dl / g, the spinning workability may be reduced.

[0090] Furthermore, in a preferred embodiment of the present invention, the elastic recovery rate of the thermoplastic polyester elastomer resin measured according to the ASTM D638 standard measurement method may be 85% to 99%.

[0091] In addition, the thermally adhesive composite fiber according to the present invention is a composite fiber obtained by conjugating and spinning the above-mentioned thermoplastic polyester elastomer resin and a low-melting polyester resin having a melting point of 230°C to 280°C, and the above-mentioned low-melting polyester resin may include at least one selected from polyethylene terephthalate (PET) resin, polybutylene terephthalate (PBT) resin, polytrimethylene terephthalate (PTT) resin and polyethylene naphthalate (PEN) resin, preferably, it may include at least one selected from polyethylene terephthalate resin, polybutylene terephthalate resin and polyethylene naphthalate resin, and more preferably, it may include polyethylene terephthalate resin.

[0092] In addition, the intrinsic viscosity of the low-melting polyester resin may preferably be 0.5 dl / g to 1.0 dl / g, more preferably 0.55 dl / g to 0.90 dl / g, and even more preferably 0.65 dl / g to 0.75 dl / g. If the intrinsic viscosity of the low-melting polyester resin is less than 0.50 dl / g, the strength of the prepared thermal adhesive composite fiber may be reduced, and if the intrinsic viscosity of the low-melting polyester resin exceeds 1.0 dl / g, the workability of spinning and stretching may be reduced.

[0093] The melting point of the low-melting polyester resin may be 230° C. to 280° C., preferably 240° C. to 265° C. If the melting point is lower than 230° C., the stability of the fiber morphology may be reduced during post-processing. On the contrary, if the melting point exceeds 280° C., the spinning workability may be problematic.

[0094] The heat-adhesive composite fiber according to the present invention is a bicomponent composite fiber obtained by conjugating and spinning the above-mentioned thermoplastic polyester elastomer resin and the low-melting polyester resin, and preferably, it can be a side-by-side type fiber or a sheath-core type fiber. Specifically, Figure 1 This is a diagram schematically showing a cross-section of a parallel composite fiber according to a preferred embodiment of the present invention. The cross-sectional shape of the composite fiber itself may vary depending on the ratio and melt viscosity between the thermoplastic polyester elastomer resin and the low-melting point polyester resin, but the cross-sectional shape of the composite fiber is not limited.

[0095] In addition, the average fineness of the thermally adhesive composite fiber according to the present invention can be 1 denier to 15 deniers, preferably, 3 denier to 10 deniers. If the average fineness is less than 1 denier, the spinnability and productivity are reduced, and the problem of reduced thickness of the fiber assembly occurs due to reduced spacing between the composite fibers and increased bonding points. If the average fineness exceeds 15 deniers, insufficient cooling occurs during spinning, the cross-section becomes uneven, and the bonding points decrease during preparation of the fiber assembly, reducing the surface uniformity of the fiber assembly.

[0096] In addition, the average fiber length of each filament of the thermally adhesive composite fiber according to the present invention can be 16 mm to 100 mm, preferably, it can be 24 mm to 96 mm, and more preferably, it can be 32 mm to 72 mm. If the average fiber length is less than 16 mm, then in the combing process of the fiber assembly, due to insufficient physical bonding of the composite fibers, the combing workability and the morphological stability of the fiber assembly may deteriorate. If the average fiber length exceeds 100 mm, in the combing process of the fiber assembly, the entanglement of the composite fibers increases, resulting in a problem of reduced surface uniformity of the fiber assembly.

[0097] In order to solve the above-mentioned problems, the present invention provides a fiber assembly including the above-mentioned thermal adhesive conjugate fiber.

[0098] In a preferred embodiment of the present invention, the fiber assembly may further include polyethylene terephthalate fibers.

[0099] In a preferred embodiment of the present invention, the detected concentrations of antimony and cobalt as heavy metals in the fiber assembly may be independently 0.1 ppm to 10 ppm.

[0100] Generally, a catalyst containing heavy metals such as antimony is used as a catalyst in the process of polymerizing polyester fibers, but the use of the catalyst is eliminated in the present invention to minimize the heavy metal content remaining in the final fibers and fiber assemblies, thereby providing materials suitable for direct contact with the human body, such as automotive interior materials, furniture panels, etc.

[0101] According to a preferred embodiment of the present invention, the compression set of the fiber assembly may be 15% or less. The compression set may be measured according to ASTM D 3574.

[0102] Furthermore, the polyethylene terephthalate fibers contained in the fiber assembly together with the thermally adhesive conjugate fibers may preferably be non-elastic polyester staple fibers.

[0103] The mixing ratio of the thermal adhesive composite fiber to the polyethylene terephthalate fiber may be 10:90 to 60:40, preferably 20:80 to 50:50, and more preferably 30:70 to 50:50, based on weight. If the ratio of the thermal adhesive composite fiber is greater than 60:40, the hardness of the fiber assembly increases, making it difficult to use it as a material for a mattress, etc., and if the ratio of the thermal adhesive composite fiber is less than 10:90, the morphological stability of the fiber assembly may decrease.

[0104] In order to solve the above-mentioned problems, the present invention provides a nonwoven fabric including the above-mentioned fiber assembly.

[0105] In addition, in order to solve the above-mentioned problems, the present invention provides a method for preparing a thermally adhesive composite fiber, and the above-mentioned method for preparing a thermally adhesive composite fiber comprises: step (1), copolymerizing a resin A including a compound represented by the following chemical formula 2 and a resin B including a compound represented by the following chemical formula 3 and at least one of a compound represented by the following chemical formula 4 through an ester exchange reaction to synthesize a thermoplastic polyester elastomer resin; step (2), conjugating and spinning the above-mentioned thermoplastic polyester elastomer resin and a polyester resin having a melting point of 230°C to 280°C.

[0106] [Chemical formula 2]

[0107]

[0108] [Chemical formula 3]

[0109]

[0110] [Chemical formula 4]

[0111]

[0112] In the above Chemical Formulae 2 to 4, P 1 and P 2 Each independently R 1 and R 2 Each independently is C 3 To C 5 Alkylene, R 3 To R 5 Each independently is C 1 To C 3 Alkylene, R 6 C 4 H 8 , n is a rational number from 5 to 45, x is a rational number from 25 to 90, y is a rational number from 10 to 75, a and c are each independently a rational number from 55 to 80, and b and d are each independently a rational number from 20 to 45.

[0113] The type and content of the resin used in the above-mentioned preparation method are the same as those described above, and thus detailed description will be omitted below.

[0114] The transesterification reaction between the resin A and the resin B can be carried out in a static mixer or a twin-screw mixer.

[0115] Specifically, the static mixer may be a high shear static mixer, and the number of divisions may be 500,000 to 5,000,000, preferably 1,000,000 to 3,000,000. When the number of divisions is less than 500,000, the copolymerization reaction is insufficient, and it is difficult to express elasticity, and it becomes a cause of reduced spinnability due to die-swell during spinning. When the number of divisions exceeds 5,000,000, the resin cannot be discharged at an equal pressure during spinning due to pressure loss in the static mixer, so there is a problem of reduced spinnability.

[0116] In a preferred embodiment of the present invention, the efficiency of the copolymerization reaction can be improved by adjusting the residence time and reaction temperature of the molten resin during the biaxial kneading. If the residence time of the molten state is less than 1 minute, the copolymerization reaction is insufficient due to insufficient reaction time, so the melting point changes slightly or it is difficult to show elasticity, and it becomes the cause of reduced spinnability due to mold release expansion during spinning. If the reaction time exceeds 5 minutes, there is a problem of physical properties deteriorating due to reduced productivity and degradation. The reaction temperature is preferably adjusted to 200°C to 270°C. If the temperature is lower than 200°C, the reaction is too slow, resulting in poor productivity. On the contrary, if the temperature exceeds 270°C, thermal decomposition will occur, making it difficult to obtain the desired fiber physical properties.

[0117] Hereinafter, embodiments of the present invention will be described in more detail. However, the scope of the present invention is not limited to the following embodiments, and those skilled in the art to which the present invention belongs may change and replace the constitution of the present invention to facilitate implementation without departing from the technical spirit of the present invention.

[0118] Modes for carrying out the invention

[0119] <Example>

[0120] Preparation Example 1

[0121] Polyester resin: The polyester resin was prepared by polycondensing terephthalic acid as an acid component and ethylene glycol as a diol component using a titanium-based polymerization catalyst. At this time, the prepared polyester resin had an intrinsic viscosity of 0.652 dl / g and a melting point of about 252°C.

[0122] Thermoplastic polyester elastomer: The thermoplastic polyester elastomer is prepared by melt-kneading resin A, which is a compound represented by the following chemical formula 2, and resin B, which is a compound represented by the following chemical formula 3. Specifically, resin A is a commercial polyester elastomer resin having an intrinsic viscosity of 1.752 dl / g, a melting point of 162° C., and a Shore A hardness of 80, and resin B is an antimony-free (Sb-free) low-melting polyester resin having an intrinsic viscosity of 0.648 dl / g and a softening point of 148° C. obtained by polycondensation using a titanium-based polymerization catalyst.

[0123] [Chemical formula 2]

[0124]

[0125] [Chemical formula 3]

[0126]

[0127] 50 parts by weight of the resin A and 50 parts by weight of the resin B were mixed to form a mixture, 0.5 parts by weight of a chain extender and 0.2 parts by weight of an antioxidant were added to 100 parts by weight of the mixture, and an ester exchange reaction was carried out using a twin-screw extruder (screw diameter: 32 mm, L / D=40).

[0128] During the above reaction and extrusion process, the resin temperature in the extruder was adjusted to 250° C., the screw speed was adjusted to 300 rpm, the residence time was adjusted to 1.5 minutes, and the prepared resin composition was cooled and sliced ​​to prepare a thermoplastic polyester elastomer resin.

[0129] Preparation Example 2

[0130] A thermoplastic polyester elastomer resin was prepared in the same manner as in Preparation Example 1 except that a low melting point polyester resin represented by the following Chemical Formula 4 having an intrinsic viscosity of 0.648 dl / g and a melting point of 143° C. was used as Resin B instead of the compound of the above Chemical Formula 3.

[0131] [Chemical formula 4]

[0132]

[0133] Preparation Example 3

[0134] The same method as Preparation Example 1 was used except that the weight ratio of Resin A to Resin B was adjusted to 4:6.

[0135] Preparation Example 4

[0136] The preparation was carried out in the same manner as in Preparation Example 1 except that the weight ratio of Resin A to Resin B was adjusted to 3:7.

[0137] Preparation Example 5

[0138] Preparation was performed in the same manner as in Preparation Example 1, except that the thermoplastic polyester elastomer resin was kneaded in a static mixer having a division number of 1.5 million divisions instead of in a twin-screw mixer.

[0139] Comparative Preparation Example 1

[0140] The same method as Preparation Example 1 was used except that the weight ratio of Resin A to Resin B was adjusted to 1:9.

[0141] Comparative Preparation Example 2

[0142] The same method as Preparation Example 1 was used except that the weight ratio of Resin A to Resin B was adjusted to 7:3.

[0143] Comparative Preparation Example 3

[0144] Preparation was performed in the same manner as in Preparation Example 1, except that a commercial polyester elastomer resin represented by the following Chemical Formula 2 was used alone as the thermoplastic polyester elastomer resin. The commercial polyester elastomer resin had an intrinsic viscosity of 1.45 dl / g, a melting point of 152° C., and a Shore D hardness of 40.

[0145] [Chemical formula 2]

[0146]

[0147] Experimental Example 1: Determination of elastic recovery rate

[0148] According to the ASTM D638 standard measurement method, a tensile specimen was prepared using the thermoplastic polyester elastomer resin prepared according to the above preparation example, and the elastic recovery rate was measured using a universal testing machine. The results are shown in Table 1 below.

[0149] Experimental Example 2: Shore Hardness Determination

[0150] The Shore D hardness of the thermoplastic polyester elastomer resin prepared according to the above preparation example was measured according to the ASTM D2240 standard measurement method. The results are shown in Table 1 below.

[0151] Experimental Example 3: Determination of soft segment molar ratio

[0152] The molar ratio of the soft segment contained in the thermoplastic polyester elastomer resin prepared according to the above-mentioned Preparation Example and Comparative Preparation Example was analyzed by NMR. The measurement results are shown in Table 1 below.

[0153] Table 1

[0154]

[0155]

[0156] *IV: Inherent Viscosity

[0157] Content in polyester elastomer resin

[0158] Example 1

[0159] Use the form Figure 1The parallel type spinneret with the cross section shown conjugate-spins the low melting point polyester resin and the thermoplastic polyester elastomer resin prepared according to the above Preparation Example 1 to produce composite fibers with a fineness of 6 deniers and a fiber length of 64 mm.

[0160] The nonwoven fabric was prepared by mixing and combing 50 wt % of the above-mentioned thermal adhesive composite fiber and 50 wt % of non-elastic polyethylene terephthalate fiber to form a nonwoven fabric, and then heat-treating the mixture in a tenter. The processing temperature of the tenter was 170° C. on the inlet side and 200° C. on the outlet side.

[0161] Example 2

[0162] The same method as in Example 1 was used except that the thermoplastic polyester elastomer resin prepared according to Preparation Example 2 was used.

[0163] Example 3

[0164] The same method as in Example 1 was used except that the thermoplastic polyester elastomer resin prepared according to Preparation Example 3 was used.

[0165] Example 4

[0166] The same method as in Example 1 was used except that the thermoplastic polyester elastomer resin prepared according to Preparation Example 4 was used.

[0167] Example 5

[0168] The same method as in Example 1 was used except that the thermoplastic polyester elastomer resin prepared according to Preparation Example 5 was used.

[0169] Example 6

[0170] In addition to using the formation Figure 2 The preparation was carried out in the same manner as in Example 1 except that a sheath-core spinneret having the cross section shown was used for conjugate spinning.

[0171] Comparative Example 1

[0172] The same preparation as in Example 1 was performed except that the thermoplastic polyester elastomer resin prepared according to Comparative Preparation Example 1 was used.

[0173] Comparative Example 2

[0174] Except for using the thermoplastic polyester elastomer resin prepared according to Comparative Preparation Example 2, the rest was prepared in the same manner as in Example 1.

[0175] Comparative Example 3

[0176] Preparation was performed in the same manner as in Example 1, except that individual fibers were made by individually spinning the thermoplastic polyester-based elastomer resin.

[0177] Experimental Example 4: Evaluation of elastic recovery rate of fiber assembly

[0178] The prepared thermally adhesive nonwoven fabric was compressed to 75% of the initial thickness over 24 hours, and the compression set of the fiber assembly was determined by the following equation 2 based on the thickness after the compression was released for 1 hour.

[0179] [Equation 2]

[0180]

[0181] The measurement results are shown in Table 2 below.

[0182] Table 2

[0183] Classification Thermally bonded composite fiber Compression set rate (%) Non-woven fabric processing yield Example 1 Preparation Example 1 9 ○ Example 2 Preparation Example 2 8 ○ Example 3 Preparation Example 3 10 ○ Example 4 Preparation Example 4 14 ○ Example 5 Preparation Example 5 9 ○ Example 6 Preparation Example 6 11 ○ Comparative Example 1 Comparative Preparation Example 1 69 ○ Comparative Example 2 Comparative Preparation Example 2 10 △ Comparative Example 3 Comparative Preparation Example 3 12 ×

Claims

1. A thermally adhesive composite fiber, It is characterized in that The thermoplastic polyester elastomer resin is a block copolymer having a melting point of 110° C. to 180° C. and including a soft segment having a structure represented by the following Chemical Formula 1 in an amount of 5 mol % to 25 mol % and conjugated with a polyester resin having a melting point of 230° C. to 280° C.: [Chemical formula 1] In the chemical formula 1, R represents C 3-5 Alkylene, n represents a rational number from 5 to 45, The thermoplastic polyester elastomer resin includes a block copolymer formed by an ester exchange reaction between resin A and resin B. The resin A includes a compound represented by the following chemical formula 2, The resin B includes at least one of a compound represented by the following Chemical Formula 3 and a compound represented by the following Chemical Formula 4: [Chemical formula 2] [Chemical formula 3] [Chemical formula 4] In the chemical formula 2 to the chemical formula 4, P 1 and P 2 Each independently R 1 and R 2 Each independently is C 3 To C 5 Alkylene, R 3 To R 5 Each independently is C 1 To C 3 Alkylene, R 6 C 4 H 8 , n is a rational number from 5 to 45, x is a rational number from 25 to 90, y is a rational number from 10 to 75, a and c are each independently a rational number from 55 to 80, b and d are each independently a rational number from 20 to 45, The thermoplastic polyester-based elastomer resin is formed by reacting the resin A and the resin B at a weight ratio of 7:3 to 2:

8.

2. The thermally adhesive composite fiber according to claim 1, It is characterized in that The melting point of the resin A is 140°C to 175°C, and the softening point of the resin B is 110°C to 150°C.

3. The thermally adhesive composite fiber according to claim 1, It is characterized in that The elastic recovery rate of the thermoplastic polyester elastomer resin measured according to the ASTM D638 standard test method is 80% to 99%.

4. A fiber assembly, It is characterized in that The thermally adhesive composite fiber according to any one of claims 1 to 3 is included.

5. The fiber assembly according to claim 4, It is characterized in that The fiber assembly further includes polyethylene terephthalate fibers.

6. The fiber assembly according to claim 4, It is characterized in that The concentrations of antimony and cobalt as heavy metals in the fiber assembly are each independently in the range of 0.1 ppm to 10 ppm.

7. A nonwoven fabric, It is characterized in that A fiber assembly comprising the fiber assembly according to any one of claims 4 to 6.

8. A method for preparing a thermally adhesive composite fiber, It is characterized in that include: Step (1), copolymerizing a resin A including a compound represented by the following chemical formula 2 and a resin B including at least one of a compound represented by the following chemical formula 3 and a compound represented by the following chemical formula 4 through an ester exchange reaction to synthesize a thermoplastic polyester elastomer resin; Step (2), conjugate spinning the thermoplastic polyester elastomer resin and a polyester resin having a melting point of 230° C. to 280° C.: [Chemical formula 2] [Chemical formula 3] [Chemical formula 4] In the chemical formula 2 to the chemical formula 4, P 1 and P 2 Each independently R 1 and R 2 Each independently is C 3 To C 5 Alkylene, R 3 To R 5 Each independently is C 1 To C 3 Alkylene, R 6 C 4 H 8 , n is a rational number from 5 to 45, x is a rational number from 25 to 90, y is a rational number from 10 to 75, a and c are each independently a rational number from 55 to 80, and b and d are each independently a rational number from 20 to 45.

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