High-strength polyethylene yarn with improved shrinkage rate and method for producing the same

Abstract

To provide high-strength polyethylene original yarn with an improved shrinkage ratio and a manufacturing method thereof.SOLUTION: A ratio (A / B) is 16 or over, wherein A is the highest point of an intensity peak formed in a scattering vector of 0-0.04Å-1 in small angle X-ray scattering (SAXS) and B is the highest point of an intensity peak formed in a scattering vector of 0.05-0.08Å-1, a shrinkage ratio is 2.5% or over, a crystallinity is 65-85%, a weight-average molecular weight (Mw) is over 300,000 g / mol and 600,000 g / mol or under, and a molecular weight distribution is over 5 and under 9.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a high-strength polyethylene yarn having an improved shrinkage rate and a method for producing the same. Specifically, it has a specific microstructure, improves shrinkage, and enables the production of high-density raw material. The present invention relates to a high-strength polyethylene yarn and a method for producing the same. [Background technology]

[0002] Not only those involved in the security field, such as police and military personnel, In many other industries, people who handle sharp cutting tools are also at constant risk of injury. To minimize the risk of injury, protective products such as gloves or clothing should be provided. It must be done.

[0003] The protective product provides adequate protection for the human body from weapons such as knives or sharp cutting tools. Therefore, it is required to have cut resistance.

[0004] To provide high cut resistance to protective products, high strength polyethylene yarn is used in the protective products. For example, high-strength polyethylene yarn is used alone to manufacture raw rolls. Or, after high-strength polyethylene yarn and other types of yarn are combined to form a plied yarn, The plied yarn can be used to manufacture a raw material.

[0005] Ultra-high molecular weight polyethylene (UHMWPE) is a type of high-strength polyethylene yarn. In order to solve the environmental problems caused by the use of organic solvents in the gel spinning method, A melt-spun yarn using high-density polyethylene with a low weight-average molecular weight has also been developed. do.

[0006] High density polyethylene polymers, unlike other polymers, have a very small number of short or long It has branched molecular chains. Due to the influence of these branched chains, The high-strength polyethylene yarns produced by the melt spinning method are mostly high in crystallinity and low in shrinkage. When the shrinkage rate is low, the yarn is used in the weaving and knitting processes to manufacture finished products. The disadvantage is that the density of the weaving and knitting of the product can only be determined by the It is necessary to manufacture a high density raw material with a higher density than the density determined by the density of the knitting. It is possible. Summary of the Invention [Problem to be solved by the invention]

[0007] One object of the present invention to solve the problems of the prior art is to provide a high strength polyethylene having an improved shrinkage ratio. The present invention provides a raw lent yarn and a method for producing the same.

[0008] It also enables the production of raw fabric that is highly cut-resistant yet provides excellent comfort when worn. The present invention provides polyethylene yarn and a method for producing the same.

[0009] In addition, it has a higher areal density than the areal density that can be adjusted in existing weaving and knitting processes. The present invention aims to provide a high-strength polyethylene yarn capable of providing a raw fabric having the above properties, and a method for producing the same. do. [Means for solving the problem]

[0010] As a result of research conducted to achieve the above object, the inventors of the present invention have discovered a method for manufacturing a semiconductor device having a specific microstructure. By producing polyethylene yarn with high shrinkage, the shrinkage rate of the yarn is improved and high strength materials are produced. The present invention was completed based on the discovery that the above-mentioned properties can be expressed.

[0011] Furthermore, by using such polyethylene yarn with an improved shrinkage rate for weaving and knitting, This allows us to provide a higher density base fabric, while also providing excellent wearability while still offering high cut resistance. The present invention was completed based on the discovery that it is possible to manufacture a raw sheet that can provide such a feeling.

[0012] The polyethylene raw yarn having the specific microstructure was analyzed by small angle X-ray scattering (S AXS) scattering vectors satisfy a specific range, and this specific microstructure We have found that it is possible to achieve the desired physical properties with raw yarn that satisfies the structure.

[0013] In the present invention, the scattering vector of small angle X-ray scattering (SAXS) described below is As long as it is possible to produce a raw yarn that satisfies a specific range, the means for producing the raw yarn is not limited. For example, The molecular weight distribution of the ethylene resin, the spinning temperature during the production of the raw yarn, the draw ratio, and the draw temperature are determined by a specific The scattering vector of the small angle X-ray scattering (SAXS) There is no limitation thereto as long as the rule satisfies the range described below.

[0014] In one aspect of the present invention, the scattering vector of small angle X-ray scattering (SAXS) is 0 to 0.04 Å. -1 To The highest point A of the intensity peak that occurs when scattering occurs and the scattering vector 0.05 to 0. 08Å -1 Ratio of the peak intensity (Intensity Peak) occurring at point A to the highest point B (A / B) The present invention relates to polyethylene yarn having a modulus of elasticity of 16 or more and a shrinkage rate of 2.5% or more.

[0015] In one embodiment, the raw yarn has a melt index (MI) measured at 190°C and 2.16 kg. The molecular weight distribution may be more than 5 and less than 9.

[0016] In one embodiment, the raw yarn may have a crystallinity of 65 to 85%. In one embodiment, the raw yarn may have a melting temperature of 130 to 140°C. In one embodiment, the raw yarn has a density of 0.93 to 0.97 g / cm 3 It is possible.

[0017] Another aspect of the present invention is a method for producing polyethylene yarn, comprising the steps of: The melt index (MI) measured at 190°C and 2.16 kg was 0.3 to 6 g / 10 min. The polyethylene chips having a molecular weight distribution of more than 5 and less than 9 are melted to produce a polyethylene melt. obtaining a melt; Spinning the polyethylene melt through a die having a plurality of nozzle holes. and, A plurality of filtrates are formed when the polyethylene melt is discharged from the nozzle holes. allowing the lament to cool; A process for converging the cooled filaments to form a multifilament yarn. Tep and drawing the multifilament yarn at a total draw ratio of 5 to 20 times and heat setting; , winding the drawn and heat-set multifilament yarn; The small-angle X-ray scattering (SAXS) vector is 0 to 0.04 Å. -1 occurs in The highest point A of the intensity peak and the scattering vector 0.05 to 0.08 Å -1 The ratio (A / B) of the peak intensity (Intensity Peak) generated at the highest point B is 16 or more. and a method for producing polyethylene yarn having a shrinkage rate of 2.5% or more.

[0018] In one embodiment, the spinning temperature of the polyethylene melt may be 220 to 300°C. In one embodiment, the maximum stretching temperature during the stretching may be 100 to 150°C.

[0019] In one embodiment, the drawing step may be performed by multi-stage drawing. In one embodiment, the stretching step is performed using a plurality of godet rollers. Ugh. In one embodiment, the drawing step is carried out in a multistage drawing process of 4 to 20 stages. Possible.

[0020] In one embodiment, the plurality of godet rollers are set at a temperature of 50 to 150°C, The temperature of the first godet roller among the plurality of godet rollers is 50 to 80°C, The temperature of the last godet roller among the plurality of godet rollers is 100 to 150°C. the law of nature, The godet rollers other than the first and last godet rollers among the plurality of godet rollers The temperature of each godet roller is the same as that of the godet roller immediately preceding it. or may be higher. [Effects of the Invention]

[0021] The polyethylene yarn of the present invention has a specific microstructure, which gives it high strength. It is also possible to provide polyethylene raw yarn having an improved shrinkage rate.

[0022] Furthermore, raw rolls of woven or knitted fabrics manufactured from such polyethylene raw yarns have been used in the past. It provides a higher density raw material than raw material manufactured using high-strength polyethylene raw material yarn. It is possible.

[0023] Furthermore, although the polyethylene fiber according to the present invention is produced by melt spinning, The high strength allows it to be used in protective products with excellent cut resistance. be. [Brief explanation of the drawings]

[0024] [Figure 1] 1 is a small angle X-ray scattering (SAXS) graph of the raw yarn according to Example 1. [Figure 2] 1 is a small angle X-ray scattering (SAXS) graph of the raw yarn according to Example 2. [Figure 3] 1 is a small angle X-ray scattering (SAXS) graph of the raw yarn according to Example 3. [Figure 4] 1 is a small angle X-ray scattering (SAXS) graph of the raw yarn according to Comparative Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0025] The present invention will be described in more detail below. Unless otherwise defined, all technical and scientific terms are understood to be within the meaning of the present invention by those skilled in the art. The terms used in the description of the present invention have the same meaning as commonly understood by one person. The terms are merely for the purpose of describing particular embodiments and are not intended to limit the invention. It is not something to do.

[0026] Furthermore, the singular forms used in the specification and the appended claims shall be used where the context clearly indicates otherwise. Unless otherwise indicated, plural forms may be intended to be included.

[0027] Furthermore, when a part is described as "including" a certain component, this means that the part "includes" the component unless otherwise specified. It means that other components may be included, rather than excluding other components. .

[0028] The inventors of the present invention have discovered a high strength polyethylene that can achieve high strength and high shrinkage. As a result, we have developed a polyethylene base material with a specific microcrystalline structure. We have found that such properties can be achieved with yarn.

[0029] Specifically, one embodiment of the present invention is a method for producing a small-angle X-ray scattering (SAXS) sample having a scattering vector of 0 to 0.04 Å -1 The highest point A of the peak intensity (Intensity Peak) and the scattering vector 0.0 5~0.08Å -1 The ratio of the peak intensity (Intensity Peak) occurring at the highest point B to the peak intensity (A / B) is 16 or more and the shrinkage rate is 2.5% or more. The target and the shrinkage ratio are within the range that satisfies the A / B and shrinkage ratio of the small angle X-ray scattering (SAXS) simultaneously. It is possible to manufacture high-density rolls of fabric that are high in strength and shrinkage. We have discovered this and completed the present invention.

[0030] The A / B ratio of the small angle X-ray scattering (SAXS) is 16 or more, preferably 18 or more, and more preferably It may be 20 or more and 40 or less. Specifically, it may be 16 to 35. A specific fine crystal structure is formed at A raw material that satisfies a shrinkage rate of 3% or more, 3.5% or more, 4% or more, specifically 2.5 to 10%. The shrinkage rate means the dry heat shrinkage rate at 100°C. In addition to the above, a high strength raw yarn can be provided.

[0031] The present invention relates to a method for manufacturing a thin film having a small angle X-ray scattering (SAXS) A / B ratio of 16 or more and a shrinkage ratio of 2.5 or less. % or more at the same time, there is no restriction on the manufacturing method. However, examples include the molecular weight distribution of polyethylene resin, the spinning temperature during the production of raw yarn, and the elongation. It can be produced by adjusting the stretch ratio and stretching temperature within a specific range.

[0032] More specifically, a polyethylene resin with a molecular weight distribution of more than 5 and less than 9 is used. The spinning temperature is 220 to 300°C, and the draw ratio is 5 to 20 times. The stretching temperature may be 100 to 150°C. However, the above conditions are merely examples. It is not limited to this. It can be implemented by changing various conditions in the ordinary technical field. and are intended only to illustrate or explain the present invention and are not intended to limit the scope of the present invention. It's not something like that.

[0033] The configuration of the present invention will be described in more detail below.

[0034] In one embodiment of the present invention, the polyethylene resin used as a raw material has a repeating unit. It means that the units are essentially ethylene, and small amounts of other monomers, such as α-olefins, may be present. acrylic acid and its derivatives, methacrylic acid and its derivatives, vinylsilanes and It may also be a copolymer of ethylene and its derivatives. A blend (mixture) of the polymer with a copolymer of other α-olefins or the like is also possible.

[0035] More preferably, copolymers of ethylene with α-olefins such as propylene and butene-1. By using the above, it is possible to incorporate short-chain or long-chain branches to some extent, which is the high yield of the present invention. It is further advantageous to provide a raw yarn having a shrinkage ratio, and this is also applicable to ethylene homopolymers. Any material that satisfies the physical properties of the invention can be used.

[0036] The polyethylene resin has a weight average molecular weight of 600, which allows for melt spinning. 000 g / mol or less, more specifically 80,000 to 600,000 g / mol. Ugh.

[0037] In one embodiment of the present invention, the polyethylene raw yarn has a molecular weight distribution of more than 5 and less than 9. The molecular weight may be, more preferably, 6 to 8, and even more preferably, 6.5 to 7.5. The molecular weight distribution is the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) (Mw / Mn) and is the polydispersity index or molecular weight distribution index. It is also called the melting point diameter (MWD). The number of minutes (MI) is 0.3 to 6 g / 10 min, and more preferably 0.4 to 3 g / 10 min It is possible.

[0038] Within the range where all of the above physical properties are satisfied, the flowability of the molten material during melt extrusion of the raw yarn is good, and the heat This prevents the occurrence of cracks and ensures processability, such as preventing thread breakage during stretching, resulting in a uniform It is possible to manufacture raw yarn with the desired properties, with high strength and a shrinkage rate of 2.5% or less. The raw yarn can be provided as above.

[0039] In addition, the density is 0.93 to 0.97 g / cm 3 , more preferably 0.941 to 0.965 g / cm 3 and the molecular weight distribution is in the range of more than 5 and less than 9. By using DPE, the crystallinity can be increased to 65-85%, more preferably 70% by melt spinning. The crystallinity of the polyethylene raw yarn can be measured by X-ray diffraction. During crystallinity analysis using a random analyzer, this can be derived along with the crystallite size.

[0040] In one embodiment, the raw yarn has a circular cross section, although the cross-sectional shape is not limited thereto. It may be a structure in which a twist or the like is formed.

[0041] In one embodiment, the polyethylene raw yarn of the present invention comprises 40 to 500 continuous filaments (co The multifilament yarn may be a bundle of continuous filaments. Each of the strands may have a fineness of 1 to 3 denier, and the polyethylene yarn is In the above range, the raw fabric is light and durable. This makes it possible to provide a raw material that is excellent in terms of durability.

[0042] Hereinafter, a method for producing a polyethylene yarn according to one embodiment of the present invention will be specifically described. The polyethylene fiber of the present invention has a small-angle X-ray scattering (SAXS) vector of 0 to 0.04 Å. -1 The highest point A of the peak intensity (Intensity Peak) and the scattering vector 0.05 0.08Å -1 Ratio of the peak intensity (Intensity Peak) generated at point A to the highest point B (A / B) If the physical properties of 16 or more and shrinkage rate of 2.5% or more are satisfied, there are no restrictions on the manufacturing method. This is not intended to be exhaustive, and the following is intended to describe one embodiment.

[0043] A method for producing a raw yarn according to one aspect of the present invention includes: The melt index (MI) measured at 190°C and 2.16 kg was 0.3 to 6 g / 10 min. The polyethylene chips having a molecular weight distribution of more than 5 and less than 9 are melted to produce a polyethylene melt. obtaining a melt; Spinning the polyethylene melt through a die having a plurality of nozzle holes. and, A plurality of filtrates are formed when the polyethylene melt is discharged from the nozzle holes. allowing the lament to cool; A process for converging the cooled filaments to form a multifilament yarn. Tep and The multifilament yarn is stretched at a total stretch ratio of 5 to 20 times and heat-set. Steps to take: winding the drawn and heat-set multifilament yarn; may include:

[0044] Each step will be explained in detail. First, polyethylene in the form of chips is is fed into an extruder 100 and melted to obtain a polyethylene melt.

[0045] The polyethylene chips may have a polydispersity index (PDI) of greater than 5 and less than or equal to 9. It has a melt index (MI) of 0.3 to 6 g / 10 min. 00g / mol or less, more specifically 80,000 to 600,000g / mol, preferably is 100,000 to 500,000 g / mol, more preferably 200,000 to 400, The polymer may have a weight average molecular weight (Mw) of 0.000 g / mol. In this range, high strength raw yarn can be produced, specifically, having a tensile strength of 10 g / d or more. The weight average molecular weight (Mw) can be 600,000 g / If the melt viscosity is too high, exceeding 1000 mol, the spinning equipment will be overloaded due to the high melt viscosity. As a result, the process is not properly controlled, making it difficult to guarantee the excellent physical properties of the raw yarn. Therefore, the polyethylene chips preferably have a molecular weight of 600,000 g / mol or less. More specifically, it is 80,000 to 600,000 g / mol, preferably 100,000 to 5 00,000 g / mol, more preferably 200,000 to 400,000 g / mol It is preferable that the polymer has a weight average molecular weight (Mw).

[0046] The molten polyethylene is conveyed through a nozzle by a screw in the extruder, The extrusion is performed through a plurality of holes formed in the die. It is determined according to the DPF (Denier Per Filament) and fineness of the raw yarn. For example, When producing a raw yarn having a total fineness of 75 denier, the spinneret has 20 to 75 holes. When a raw yarn having a total fineness of 450 denier is produced, The gold may have 90 to 450 holes, preferably 100 to 400 holes.

[0047] The melting process in the extruder and the extrusion process through the die are The melting point can be changed depending on the application. For example, the melting point is 150 to 315°C. The reaction may be carried out preferably at 220 to 300°C, more preferably at 250 to 290°C. That is, the temperature of the extruder and die is 150 to 315°C, preferably 220 to 300°C, more preferably It is preferable to maintain the temperature at 250 to 290°C.

[0048] When the spinning temperature is less than 150°C, the polyethylene is not uniformly dispersed due to the low spinning temperature. In contrast, when the spinning temperature exceeds 315°C, If the polyethylene is heated, thermal decomposition of the polyethylene may occur, and the desired strength may not be achieved. do.

[0049] The ratio (L / D) of the hole length L to the hole diameter D in the die is 3 to 40. If L / D is less than 3, die swell may occur during melt extrusion. This makes it difficult to control the elastic behavior of polyethylene, resulting in poor spinnability. When L / D exceeds 40, necking of the molten polyethylene passing through the nozzle occurs. In addition to thread breakage due to the ing phenomenon, non-uniform discharge due to pressure drop can occur.

[0050] The molten polyethylene is extruded from the holes in the spinneret, and the difference between the spinning temperature and room temperature causes the polyethylene to The polyethylene begins to solidify, forming a semi-solid filament. In this case, not only semi-solidified filaments but also completely solidified filaments are Both are called "filaments."

[0051] The plurality of filaments are cooled in a cooling zone (or "quenching zone"). The filament is cooled by air cooling. It is possible.

[0052] The filament cooling in the cooling section uses cooling air at a speed of 0.2 to 1 m / sec. It is preferable that the cooling temperature is 15 to 40°C. If the temperature is less than this, the elongation will be insufficient due to supercooling, and yarn breakage may occur during the drawing process. If the cooling temperature exceeds 40°C, the fineness between the filaments may increase due to uneven solidification. The deviation becomes large and thread breakage may occur during the drawing process.

[0053] Furthermore, by performing multi-stage cooling in the cooling section, crystallization can be performed more uniformly. It can be done like this.

[0054] More specifically, the cooling section is divided into three or more sections. For example, three cooling sections. When the cooling system consists of three parts, the temperature is designed to gradually decrease from the first cooling section to the third cooling section. Specifically, the first cooling section is set to 40 to 80°C. The second cooling section can be set to 30 to 50°C, and the third cooling section can be set to 15 to 30°C.

[0055] In addition, by setting the air velocity in the first cooling section to the highest, the surface becomes smoother and the fibers Specifically, the first cooling section is a cooling section that is cooled by a wind speed of 0.8 to 1 m / sec. The temperature is cooled to 40-80°C using wind, and the second cooling section is at a speed of 0.4-0.6 m / s The temperature is cooled to 30-50°C using cooling air at a speed of 0.2-1 / 2. The temperature is cooled to 15-30°C using cooling air with a speed of 0.5m / sec. By adjusting the conditions in this way, the crystallinity becomes higher and the surface becomes smoother. The raw yarn can be produced.

[0056] Next, the cooled and completely solidified filaments are bundled by a bundler to form a multi-fiber Form a lament.

[0057] The polyethylene yarn of the present invention may be produced by a direct spin-draw (DSD) process. That is, the multifilament is directly drawn into a multistage drawing section including a plurality of godet roller sections. The film is then stretched in multiple stages at a total stretch ratio of 5 to 20 times, preferably 8 to 15 times, and then It can be wound onto the underside.

[0058] As an example, the drawing step using a plurality of godet rollers is a multi-stage drawing step of four or more stages. Preferably, the stretching step is carried out using a plurality of godet rollers. In this case, the multistage drawing may be performed in 4 stages or more and 20 stages or less. In this case, sudden stretching occurs in each section of the godet roller, which causes fluffing during the production of filament yarn. The frequency of the fibers increases, the initial modulus increases, and the raw fabric may become excessively stiff. When the multistage drawing is performed in 20 stages or more, the friction between the filament yarn and the godet roller increases. This can increase the strain and cause filament damage and breakage.

[0059] In addition, the polydispersity index (PDI) is between 5 and 9, and the melting index is between 0.3 and 6 g / 10 min. Even if polyethylene chips having a melt index (MI) of 190°C are used, the present invention If the conditions for the draw ratio, draw temperature, and number of stages are not met, the desired physical properties may be obtained. For example, the maximum stretching temperature is 100 to 150°C. It is preferable that the total stretching ratio is 5 to 20 times and that multi-stage stretching of 4 or more stages is performed. The maximum drawing temperature means the highest temperature in the drawing section, and the total drawing ratio is , refers to the final draw ratio of the fiber after the final draw compared to the fiber before drawing.

[0060] For example, the multi-stage stretching may be performed using a plurality of godet rollers in four or more stages, more specifically, four stages. The drawing may be performed in a multi-stage drawing of 20 stages or more. The temperature of the first godet roller GR1 among GRn can be 50-80°C. The temperature of the last godet roller GRn may be 100 to 150°C. and each of the remaining godet rollers except for the last godet roller section (GR1, GRn) The temperature of the godet roller is set to be equal to or higher than that of the godet roller of the previous stage. The temperature of the last godet roller portion GRn can be determined by the temperature of the godet roller portion of the immediately preceding stage. It can be set to the same temperature as or higher than the temperature of It is possible that this will happen.

[0061] In addition, during multi-stage stretching, by giving a shrinkage stretch (relaxation) of 1 to 5% in the last stretching section, This makes it possible to provide a yarn with even greater durability.

[0062] To give a more specific example, the multi-stage drawing unit is composed of a total of four godet roller sections. The first godet roller section is stretched 2 to 4 times at 50 to 80°C, and the second godet roller section is stretched 2 to 4 times at 50 to 80°C. The dead roller stretches the film 3 to 10 times at 70 to 100°C, and the third godet roller stretches the film 3 to 10 times at 80 to 1 At 10°C, the stretch rate is 1.1 to 3 times, and at 100 to 150°C, the shrinkage rate is 1 to 5% at the 4th godet roller. The first godet roller portion may be configured to perform shrinking and stretching (relaxation). Each of the fourth godet roller sections may be formed of a plurality of godet rollers. For example, it may be formed of two or more godet rollers, more specifically, two to ten godet rollers. do.

[0063] Alternatively, the multifilament may be wound as an undrawn yarn, and then the undrawn yarn may be wound. The polyethylene raw yarn of the present invention can be produced by drawing the drawn yarn. That is, the polyethylene raw yarn of the present invention is produced by melt-spinning polyethylene to produce an undrawn yarn. It may also be produced by a two-stage process in which the undrawn yarn is then drawn.

[0064] If the total draw ratio applied in the drawing process is less than 5, the final polyethylene raw yarn The crystallinity of the polymer cannot be 65% or more, and the A / B ratio of small angle X-ray scattering (SAXS) is 1. 6 or more and the shrinkage rate cannot be achieved. There is a risk of pilling being induced on the rolls produced from the raw yarn.

[0065] On the other hand, if the total stretching ratio exceeds 20 times, thread breakage may occur. The strength of the polyethylene yarn obtained as a result is not suitable, and the weaving properties of the polyethylene yarn are poor. Not only is this not good, but the fabric made using it is too stiff, making it difficult for users to use. It can be inconvenient.

[0066] The linear speed of the first godet roller GR1, which determines the spinning speed of the melt spinning of the present invention, is determined. When the multi-stage drawing section is used, the total drawing ratio is 5 to 20 times, preferably 8 to 15 times. The linear speed of the remaining godet rollers is determined appropriately so that it can be applied to multifilaments. can be.

[0067] The multi-stage drawing section simultaneously performs multi-stage drawing and heat setting of the multifilament. The multi-stage drawn multifilament is wound on the winder, and A clear polyethylene yarn is completed.

[0068] The polyethylene fiber of the present invention produced as described above is suitable for use in protective films that require excellent cut resistance. It can be used to manufacture protective products (e.g., protective gloves, underwear, bags, etc.).

[0069] The present invention will be described in more detail below based on examples and comparative examples. The examples and comparative examples are merely examples for explaining the present invention in more detail, and are not intended to be limiting unless otherwise specified. However, the present invention is not limited by the following examples and comparative examples. The physical properties were measured as follows.

[0070] <Weight average molecular weight (Mw) (g / mol) and polydispersity index (PDI)> The polyethylene yarn was completely dissolved in the following solvent and then subjected to the following gel permeation chromatography: The weight average molecular weight (Mw) and polydispersity index of the polyethylene yarn were measured using gel permeation chromatography (GPC). The PDI (Mw / Mn:PDI) was calculated for each of the samples.

[0071] -Analytical equipment: Tosoh HLC-8321GPC / HT -Column: PLgel guard (7.5 x 50 mm) + 2 x PLgel mixed-B (7.5 x 30 0mm) -Column temperature: 160℃ Solvent: Trichlorobenzene (TCB) + 0.04 wt.% dibutylhydroxytoluene (BHT)(after drying with 0.1% CaCl2) -Injector and detector temperature: 160℃ -Detector: RI Detector -Flow rate: 1.0ml / min -Injection volume: 300mL -Sample concentration: 1.5mg / mL -Standard sample: polystyrene

[0072] <Tensile strength (g / d), initial modulus (g / d), and elongation (%)> According to ASTM D2256 method, Instron Engineering Corp. (Ca The deformation-stress curve of the polyethylene yarn was obtained using a universal tensile tester (Nton, Massachusetts). The sample length was 250 mm, the tensile speed was 300 mm / min, and the initial load ( The load was set to 0.05 g / d. The stress and elongation at the breaking point were used to calculate the tensile strength. The degree of elongation (g / d) and the elongation rate (%) are calculated, and the maximum gradient of the curve near the origin is calculated. The initial modulus (g / d) was calculated from the tangent line. After five measurements were taken for each raw yarn, The average value was calculated.

[0073] <Crystallization of raw yarn> XRD equipment (X-ray Diffractometer) [Manufacturer: PANalytical, Model: EM The crystallinity of polyethylene yarn was measured using a PYREAN. The raw fiber was cut to prepare a sample having a length of 2.5 cm. After fixing the sample in a holder, measurements were carried out under the following conditions.

[0074] Light source (X-ray Source):Cu-Kα radiation Power: 45KV x 25mA Mode: Continuous scan mode Scan angle range: 10~40° Scan speed: 0.1° / sec

[0075] <Melting index> Measured at 190°C and 2.16 kg in accordance with ASTM D1238.

[0076] <Small angle X-ray scattering> XRD equipment (X-ray Diffractometer) [Manufacturer: PANalytical, Model: EM PYREAN] was used for measurement.

[0077] From the measured graph, the scattering vector is 0 to 0.04 Å. -1 The peak intensity (In The highest point A of the ion-excited ... -1 Peaks that occur at The ratio (A / B) of the peak intensity to the highest point B was calculated.

[0078] Light source (X-ray Source):Cu-Kα radiation Power: 45KV x 40mA Mode: Continuous scan mode Scan angle range: 0.1~2.0° Scan speed: 0.01° / sec

[0079] <Shrinkage rate> The polyethylene yarn was cut to obtain a sample of 70 cm length, and both ends of the sample were The display was placed at a distance of 10 cm from each other (i.e., the distance between the display points = 50 cm m) Next, the sample was hung on a jig so that no load was applied to it, and the sample was placed in a hot air circulatory system. The sample was heated at 100°C for 30 minutes in a circular furnace. After the sample was taken out and allowed to cool slowly to room temperature, the distance between the indicated points was measured. The dry heat shrinkage of the polyethylene yarn at 100°C was calculated using the data.

[0080] Dry heat shrinkage rate (%)=[(L0-L1) / L0]×100 (where L0 is the distance between the display points before heating (i.e., 50 cm), and L1 is , the distance between the indicated points after heating.)

[0081] The average dry heat shrinkage obtained from the two tests was calculated.

[0082] [Example 1] <Production of polyethylene yarn> Produce polyethylene yarn containing 240 filaments with a total fineness of 500 denier. Ta.

[0083] Specifically, 0.962 g / cm 3 density, weight average molecular weight of 340,000 g / mol (Mw), a molecular weight distribution of 7.5, and a melt index (MI at 1 Polyethylene chips having a temperature of 90°C were fed into the extruder and melted. The resin was extruded through a die with 240 holes. The diameter of the holes in the die The ratio of the hole length L to D (L / D) was 6. The die temperature was 260°C. .

[0084] The filament formed by extrusion from the nozzle hole of the die is divided into three sections. The first cooling section was cooled by cooling air with a speed of 0.9 m / sec. In the second cooling section, the temperature is cooled to 35°C by cooling air with a speed of 0.5 m / sec. In the third cooling section, the material was finally cooled to 25°C by cooling air at a speed of 0.4 m / sec. After cooling, the fibers were bundled into a multifilament yarn using a bundler.

[0085] The multifilament yarn then moved to a drawing section, which consisted of four sections: It consists of a multi-stage extension section and a total of four godet roller sections, each of which is The first godet roller section has a maximum temperature of 80°C. The maximum temperature of the second godet roller is 90°C, the maximum temperature of the third godet roller is 95°C, The maximum temperature of the fourth godet roller was set at 120°C, and the draw ratio was The first godet roller stretches the paper twice, the second godet roller stretches it three times, and the third godet roller stretches it three times. In the fourth godet roller section, the paper is stretched 1.4 times, and in the fourth godet roller section, the paper is stretched 1.4 times. The stretched part is stretched to a total stretch ratio of 8 times, and the stretched part is stretched to a total stretch ratio of 4% compared to the stretched part. Fixed.

[0086] The drawn multifilament yarn was then wound onto a winder. was 0.8g / d.

[0087] The physical properties of the produced yarn were measured and are shown in Table 1 below. In addition, small angle X-ray scattering (SAXS) The small-angle X-ray scattering (SAXS) scattering vectors were measured and shown in Figure 1. -1 The highest point A of the peak intensity (Intensity Peak) and the scattering vector 0.05 to 0 .08Å -1 Ratio of the peak intensity (Intensity Peak) generated at point A to the highest point B (A / B) was 28.

[0088] [Example 2] <Production of polyethylene yarn> In Example 1, the total stretch ratio was adjusted to 11 times. A raw yarn was produced in the same manner as in Example 1.

[0089] The physical properties of the produced yarn were measured and are shown in Table 1 below. In addition, small angle X-ray scattering (SAXS) The small-angle X-ray scattering (SAXS) scattering vectors were measured and shown in Figure 2. -1 The highest point A of the peak intensity (Intensity Peak) and the scattering vector 0.05 to 0. 08Å -1 The ratio (A / B) of the peak intensity (Intensity Peak) generated at the highest point B is It was 27.5.

[0090] [Example 3] <Production of polyethylene yarn> In Example 1, the total stretch ratio was adjusted to 13 times. A raw yarn was produced in the same manner as in Example 1.

[0091] The physical properties of the produced yarn were measured and are shown in Table 1 below. In addition, small angle X-ray scattering (SAXS) The small-angle X-ray scattering (SAXS) scattering vectors were measured and shown in Figure 3. -1 The highest point A of the peak intensity (Intensity Peak) and the scattering vector 0.05 to 0. 08Å -1 The ratio (A / B) of the peak intensity (Intensity Peak) generated at the highest point B is It was 22.6.

[0092] [Example 4] <Production of polyethylene yarn> In Example 1, 0.961 g / cm 3 density of 340,000 g / mol weight-average molecular weight (Mw), molecular weight distribution of 5.5, and melt index ( A polyethylene chip with a stretch ratio of 13 was used. The yarn was produced in the same manner as in Example 1, except that the yarn was adjusted to

[0093] The physical properties of the produced yarn were measured and are shown in Table 1 below. Small angle X-ray scattering (SAXS) Vector 0~0.04Å -1 The highest point A of the intensity peak that occurs at Scattering vector 0.05~0.08Å -1 The maximum intensity peak that occurs at The ratio to high point B (A / B) was 16.

[0094] [Example 5] <Production of polyethylene yarn> In Example 1, 0.961 g / cm 3 density of 340,000 g / mol It had a weight-average molecular weight (Mw), a molecular weight distribution of 8, and a melt index (MI) of 1.6 g / 10 min. A polyethylene chip with a temperature of 190°C was used, and the total stretching ratio was adjusted to 13 times. The yarn was produced in the same manner as in Example 1, except that the yarn was cut.

[0095] The physical properties of the produced yarn were measured and are shown in Table 1 below. Small angle X-ray scattering (SAXS) Vector 0~0.04Å -1 The highest point A of the intensity peak that occurs at Scattering vector 0.05~0.08Å -1 The maximum intensity peak that occurs at The ratio to high point B (A / B) was 18.

[0096] [Comparative Example 1] <Production of polyethylene yarn> In Example 1, 0.960 g / cm 3 density of 340,000 g / mol It had a weight-average molecular weight (Mw), a molecular weight distribution of 3, and a melt index (MI) of 1.5 g / 10 min. A polyethylene chip with a temperature of 190°C was used, and the total stretching ratio was adjusted to 11 times. The yarn was produced in the same manner as in Example 1, except that the yarn was cut.

[0097] The physical properties of the produced yarn were measured and are shown in Table 1 below. In addition, small angle X-ray scattering (SAXS) The small-angle X-ray scattering (SAXS) scattering vectors were measured and shown in Figure 4. -1 The highest point A of the peak intensity (Intensity Peak) and the scattering vector 0.05~ 0.08Å -1 The ratio of the peak intensity (Intensity Peak) occurring at the highest point B to the peak intensity (A / B) was 15.

[0098] [Table 1]

[0099] Although the present invention has been described above with reference to specific and limited examples and drawings, The above examples are merely provided for a more general understanding of the present invention. It is understood by those skilled in the art that the present invention pertains to the present invention that Many modifications and variations are possible in light of the above teachings.

[0100] Therefore, the spirit of the present invention should not be limited to the described embodiments, but should be understood to be within the scope of the following claims. Not only the scope of the claims described above, but also equivalent or equivalent modifications to the scope of the claims All of these can be said to fall within the scope of the concept of the present invention.

Claims

1. Small angle X-ray scattering (SAXS) scattering vector 0-0.04 Å －１ The highest point A of the intensity peak that occurs at 0.05 to 0.08 Å and the scattering vector －１ the ratio (A / B) of the peak intensity (Intensity Peak) occurring at point A to the highest point B is 16 or more, the shrinkage rate is 2.5% or more, and the crystallinity is 65 to 85%, The weight average molecular weight (Mw) is more than 300,000 g / mol and not more than 600,000 g / mol; A polyethylene raw yarn having a molecular weight distribution of more than 5 and less than 9.

2. 2. The polyethylene yarn according to claim 1, wherein the yarn has a melt index (MI) measured at 190°C and 2.16 kg of 0.3 to 6 g / 10 min.

3. The polyethylene yarn according to claim 1, wherein the yarn has a melting temperature of 130 to 140°C.

4. The raw yarn has a density of 0.93 to 0.97 g / cm ３ The polyethylene fiber according to claim 1,

5. A polyethylene raw yarn as described in claim 1, having a melt index (MI) measured at 190°C and 2.16 kg of 0.3 to 6 g / 10 min and a molecular weight distribution of more than 5 and less than 9.

6. The polyethylene raw yarn is Melting the polyethylene chips to obtain a polyethylene melt; Spinning the polyethylene melt through a die having a plurality of nozzle holes; cooling the plurality of filaments formed when the polyethylene melt is extruded from the nozzle holes; converging the cooled filaments to form a multifilament yarn; drawing and heat setting the multifilament yarn at a total draw ratio of 5 to 20 times; winding the drawn and heat-set multifilament yarn; Including, 2. The method for producing polyethylene yarn according to claim 1, wherein the step of cooling the plurality of filaments comprises a step of performing multi-stage cooling in a cooling unit having three cooling sections designed so that the temperature gradually decreases from the first cooling unit to the third cooling unit.

7. A method for producing polyethylene raw yarn as described in Claim 6, wherein the drawing is performed in a multi-stage drawing process of 4 to 20 stages.

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