KR20230075098A - Polyolefin monofilament yarn having improved abrasion resistance, method of manufacturing the same, and molded article manufactured thereby - Google Patents

Abstract

The present invention relates to a polyolefin-based monofilament yarn having improved abrasion resistance, a manufacturing method thereof, and a molded article manufactured thereby. More specifically, the present invention mixes a proper amount of a stiff nucleus agent with a base resin containing homo polypropylene and high density polyethylene and uses a high temperature tensile testing machine to continuously perform multi-layered stretching and room temperature cooling processes, thereby manufacturing polyolefin-based monofilament with improved mechanical physical properties including flexural modulus and flexural strength because a crystal size in a resin composition is made small to improve abrasion resistance, and phase separation does not occur. In addition, the polyolefin-based monofilament yarn of the present invention is small in terms of weights compared to other monofilaments such as nylon, polyester, etc. so that the polyolefin-based monofilament yarn is not sunk in water, is excellent hydrophobic, and is inexpensive compared to other organic fibers, and accordingly, using the advantages, the polyolefin-based monofilament yarn can be applicable to stretched fibers, ropes or fish nets and cords for fishery.

Description

Polyolefin monofilament yarn having improved abrasion resistance, method of manufacturing the same, and molded article manufactured thereby}

The present invention relates to a polyolefin-based monofilament yarn having improved abrasion resistance, a method for producing the same, and a molded product manufactured thereby.

Polypropylene resin not only exhibits excellent molding processability and chemical resistance, but also has relatively excellent tensile strength, flexural modulus, and stiffness, and is inexpensive, so it is applied to applications such as extrusion and injection. However, since the crystal grains are structurally not dense and the abrasion resistance is weak, improvement in the abrasion resistance of polypropylene is required for commercial application.

Since the crystal particles related to the abrasion resistance of polypropylene vary according to the characteristics of the resin itself, such as molecular weight, molecular weight distribution, and isotactic index, in order to meet the mechanical properties and abrasion resistance required for commercial finished products, Various methods such as improving the isotactic index, changing the processing conditions or adding a nucleating agent are introduced.

However, there is no clear study on the relationship between crystal grains and abrasion resistance of mono yarns of polyolefin ropes used in fishery ropes or fishing nets, so there is an urgent need for technology development.

Korea Patent No. 10-0838040

In order to solve the above problems, an object of the present invention is to provide a polyolefin-based monofilament yarn having improved wear resistance and mechanical properties.

An object of the present invention is to provide a molded article made of the polyolefin-based monofilament yarn of the present invention.

In addition, an object of the present invention is to provide a method for producing a polyolefin-based monofilament yarn capable of producing a high-stretched polyolefin-based monofilament yarn in a short time using multi-step drawing of a high-temperature tensile tester.

The present invention relates to a polyolefin-based resin composition comprising 0.05 to 0.2 parts by weight of a rigid nucleating agent based on 100 parts by weight of a base resin containing 65 to 85% by weight of homo polypropylene and 15 to 35% by weight of high-density polyethylene at a temperature of 190 to 270 ° C. A polyolefin-based monofilament yarn obtained by two-stage stretching of an extruded product obtained by extrusion with a single-screw or twin-screw extruder with a high-temperature tensile tester, wherein the high-density polyethylene has a density of 0.910 to 0.980 g/cm ³ , and the rigid nucleating agent is sodium Benzoate, phosphate sodium salt or a mixture thereof, the polyolefin monofilament yarn has a draw ratio of 9 to 14, a fineness of 1500 to 1900 denier, and tenacity measured according to ASTM D 638 Provides a polyolefin-based monofilament yarn of 9 to 13 gf / denier.

In addition, the present invention provides a molded article made of the polyolefin-based monofilament yarn according to the present invention.

In addition, the present invention provides a polyolefin-based resin composition comprising 0.05 to 0.2 parts by weight of a rigid nucleating agent based on 100 parts by weight of a base resin containing 65 to 85% by weight of homo polypropylene and 15 to 35% by weight of high-density polyethylene Preparing a polyolefin-based resin composition; Extruding the polyolefin-based resin composition at a temperature of 190 to 270 ° C. and then cutting to prepare an extruded product; Injecting the extruded product into a high-temperature tensile tester and performing primary stretching at a temperature of 100 to 150 °C; firstly cooling the firstly stretched extruded material to room temperature; Secondary stretching at a temperature of 100 to 150 ° C. after cutting the first extruded material cooled to room temperature; And preparing a polyolefin-based monofilament yarn by secondarily cooling the secondarily drawn extruded discharge material to room temperature, wherein the high-density polyethylene has a density of 0.910 to 0.980 g/cm ³ , and the rigid nucleating agent is sodium benzoate. 8, phosphate sodium salt, or mixtures thereof, and the polyolefin-based monofilament yarn has a draw ratio of 9 to 14, a fineness of 1500 to 1900 denier, and a tenacity measured according to ASTM D 638. It provides a method for producing a polyolefin-based monofilament yarn that is 9 to 13 gf / denier.

The polyolefin-based monofilament yarn according to the present invention is determined in the resin composition by mixing an appropriate amount of a rigid nucleating agent with a base resin including homo polypropylene and high-density polyethylene, and then continuously performing multi-step drawing and cooling at room temperature using a high-temperature tensile tester. By reducing the size, abrasion resistance is improved, and phase separation does not occur, so that polyolefin monofilaments having improved mechanical properties such as flexural modulus and flexural strength can be manufactured.

In addition, the polyolefin-based monofilament yarn according to the present invention has a low specific gravity compared to other monofilaments such as nylon and polyester, does not sink in water, has excellent hydrophobicity, and has advantages of being cheaper than conventional organic fibers. Furthermore, there is an advantage that can be applied to stretched fibers, fishery ropes or fishing nets, and cords using this.

The effects of the present invention are not limited to the effects mentioned above. It should be understood that the effects of the present invention include all effects that can be inferred from the following description.

1 schematically shows a process for manufacturing a polyolefin-based monofilament yarn according to the present invention using multi-stage stretching of a high-temperature tensile tester.
Figure 2 is a photograph showing the abrasion tester device.

Hereinafter, the present invention will be described in more detail as an embodiment.

The present invention relates to a polyolefin-based monofilament yarn having improved abrasion resistance, a method for producing the same, and a molded product manufactured thereby.

As described above, conventional polypropylene resins have problems in reducing shrinkage, preventing distortion or warping in molded products, and causing surface defects, and thus their application range is limited.

Therefore, in the present invention, after mixing an appropriate amount of a rigid nucleating agent with a base resin including homo polypropylene and high-density polyethylene, a polyolefin-based monofilament yarn is prepared by continuously performing multi-stage drawing and cooling at room temperature using a high-temperature tensile tester, thereby preparing a resin composition. Wear resistance can be improved by reducing the size of the inner crystal, and mechanical properties such as flexural modulus and flexural strength can be improved because phase separation does not occur.

In addition, the polyolefin-based monofilament yarn of the present invention has a low specific gravity compared to other monofilaments such as nylon and polyester, does not sink in water, has excellent hydrophobicity, and has advantages of being cheaper than conventional organic fibers. Furthermore, there is an advantage that can be applied to stretched fibers, fishery ropes or fishing nets, and cords using this.

Specifically, the present invention relates to a polyolefin-based resin composition comprising 0.05 to 0.2 parts by weight of a rigid nucleating agent based on 100 parts by weight of a base resin containing 65 to 85% by weight of homo polypropylene and 15 to 35% by weight of high-density polyethylene at 190 to 270 ° C. A polyolefin-based monofilament yarn obtained by two-stage stretching of an extruded product obtained by extrusion with a single-screw or twin-screw extruder at a temperature with a high-temperature tensile tester, wherein the high-density polyethylene has a density of 0.910 to 0.980 g/cm ³ , and the rigid nucleating agent is sodium benzoate, phosphate sodium salt, or a mixture thereof, and the polyolefin-based monofilament yarn has a draw ratio of 9 to 14, a fineness of 1500 to 1900 denier, and strength measured according to ASTM D 638 ( tenacity) provides a polyolefin-based monofilament yarn of 9 to 13 gf / denier.

The homo polypropylene may have a melt flow index (230 ° C, 2.16 kg) of 1 to 10 g/10 min, preferably 2 to 7 g/10 min, and most preferably 3 to 5 g/10 min. g/10 min. At this time, when the melt flow index of the homopolypropylene does not satisfy the above range, yarn strength and elongation may decrease.

The high-density polyethylene may have a density of 0.910 to 0.980 g/cm ³ , preferably 0.950 to 0.965 g/cm ³ . In addition, the high-density polyethylene may have a melt flow index (Melt Flow Index, 190 ° C, 2.16 kg) of 0.1 to 5 g / 10 min, preferably 0.3 to 2 g / 10 min, and most preferably 0.5 to 0.7 g/10 min. At this time, if the density and melt flow index of the high-density polyethylene do not satisfy all of the respective ranges, mechanical properties and yarn strength may be reduced.

The base resin may include 65 to 85% by weight of homo polypropylene and 15 to 35% by weight of high density polyethylene, preferably 70 to 80% by weight of homo polypropylene and 20 to 30% by weight of high density polyethylene, , most preferably 73 to 77% by weight of homo polypropylene and 23 to 27% by weight of high-density polyethylene.

The rigid nucleating agent reduces the crystal size so that the fine-sized crystals are evenly distributed in the polyolefin resin composition, so that the interface between the base resin and the crystals is reduced and phase separation does not occur, thereby improving mechanical properties such as flexural modulus and flexural strength, and at the same time improving wear resistance can be significantly improved.

The hard nucleating agent may be sodium benzoate, sodium phosphate salt type or a mixture thereof, preferably sodium benzoate. The hard nucleating agent may be 0.05 to 0.2 parts by weight, preferably 0.1 to 0.18 parts by weight, and most preferably 0.13 to 0.16 parts by weight, based on 100 parts by weight of the base resin. If the content of the rigid nucleating agent is less than 0.05 parts by weight, wear resistance properties may not appear evenly, and conversely, if it exceeds 0.2 parts by weight, the effect of improving wear resistance is insufficient and economical efficiency is poor.

The polyolefin-based monofilament yarn is a polyolefin-based monofilament yarn obtained by extruding the extruded product obtained by extruding with a single-screw or twin-screw extruder at a temperature of 190 to 270 ° C. in two stages with a high-temperature tensile tester, and the draw ratio is 9 to 14, the fineness is 1500 to 1900 denier, and the strength (tenacity) measured according to ASTM D 638 may be 9 to 13 gf / denier. Preferably, the draw ratio may be 12 to 13, the fineness may be 1800 to 1850 denier, and the strength may be 9.7 to 10 gf/denier.

In addition, the polyolefin-based resin composition may have a flexural modulus of 1420 to 1470 Mpa, a flexural strength of 38.4 to 38.9 Mpa, and a melting point of 162.4 to 165 °C, measured according to ASTM D 790. Preferably, the flexural modulus may be 1450 to 1460 Mpa, the flexural strength may be 38.8 to 38.9 Mpa, and the melting point may be 162.7 to 162.9 °C.

On the other hand, the present invention provides a molded article made of the polyolefin-based monofilament yarn according to the present invention.

In addition, the present invention provides a polyolefin-based resin composition comprising 0.05 to 0.2 parts by weight of a rigid nucleating agent based on 100 parts by weight of a base resin containing 65 to 85% by weight of homo polypropylene and 15 to 35% by weight of high-density polyethylene Preparing a polyolefin-based resin composition; Extruding the polyolefin-based resin composition at a temperature of 190 to 270 ° C. and then cutting to prepare an extruded product; Injecting the extruded product into a high-temperature tensile tester and performing primary stretching at a temperature of 100 to 150 °C; firstly cooling the firstly stretched extruded material to room temperature; Secondary stretching at a temperature of 100 to 150 ° C. after cutting the first extruded material cooled to room temperature; And preparing a polyolefin-based monofilament yarn by secondarily cooling the secondarily drawn extruded discharge material to room temperature, wherein the high-density polyethylene has a density of 0.910 to 0.980 g/cm ³ , and the rigid nucleating agent is sodium benzoate. 8, phosphate sodium salt, or mixtures thereof, and the polyolefin-based monofilament yarn has a draw ratio of 9 to 14, a fineness of 1500 to 1900 denier, and a tenacity measured according to ASTM D 638. It provides a method for producing a polyolefin-based monofilament yarn that is 9 to 13 gf / denier.

1 schematically shows a process for manufacturing a polyolefin-based monofilament yarn according to the present invention using multi-stage stretching of a high-temperature tensile tester. Referring to FIG. 1 , first, in step (1a), the extruded product is fixed to the grip of a tensile tester in an oven set to a stretching temperature, the temperature is stabilized for 5 minutes, and then the primary stretching is performed. Subsequently, immediately after the first stretching in step (1b), a room temperature cooling process is performed for 5 minutes while fixing the stretched extruded material to the grip. In the next step (1c), immediately after the room temperature cooling process, the firstly stretched extruded material is detached from the grip and then cut into a short length of 20 to 30 cm. In step (1d), the cut extruded material is fixed to a grip having a distance between grips of 18 to 28 cm, and temperature stabilization is performed for 5 minutes. Finally, step (1e) shows the process of producing a highly stretched polyolefin-based monofilament by terminating the secondary drawing at 90 to 95% of the strain that leads to ductile failure after temperature stabilization and proceeding with a cooling process at room temperature for 5 minutes.

Hereinafter, each step will be described in detail.

In the step of preparing the extruded discharge product, the polyolefin-based resin composition may be extruded at a temperature of 190 to 270 ° C. using a single screw extruder and a cutting machine, passing through the single screw extruder An extruded discharged product can be produced by passing the discharged reactant through a cooling water bath at 25 to 35°C and then taking it out with a cutting machine at a speed of 5 to 15 m/min.

The extruded product preferably has a diameter of 1.5 to 3.0 mm and a length of 10 to 20 cm. When the extruded material is cut in the above diameter and length ranges, multi-stage stretching using a high-temperature tensile tester is possible in a later step, and thus a polyolefin-based monofilament having a high elongation rate can be manufactured. However, if the diameter and length of the extruded material are out of the above range, the high-temperature tensile tester has a limited vertical test space, so that it is impossible to simulate the manufacture of a polyolefin-based monofilament with a high elongation rate of 10 times or more.

In the primary stretching step, the primary stretching may be completed in a strain hardening section in which orientation of the polymer chains and cross-sectional shrinkage of the extruded product uniformly occur after passing through a specific stretching ratio. Specifically, in the primary stretching, the extruded product is fixed to a grip having a distance between grips of 6.5 to 7.5 cm of a high-temperature tensile tester, and the extrusion product is stretched at a temperature of 100 to 150 ° C so that the length of the extruded product is 20 to 30 cm. can make it At this time, when the length of the extruded material is out of the above range, it is difficult to perform secondary drawing, which is a subsequent process, and it is difficult to manufacture and simulate a high-elongation monofilament. In particular, the length of the extruded material should be 1.5 to 3 times longer than the distance between the grips so that it can be drawn without single yarn in the necking section and stably stretched until the strain hardening, which is the end section of the first drawing.

The primary stretching may be performed at a temperature of 100 to 150 °C, preferably at a temperature of 100 to 150 °C, and most preferably at a temperature of 110 to 120 °C. At this time, if the temperature of the primary stretching is less than 100 ℃, the extruded material may not be sufficiently stretched, conversely, if it exceeds 150 ℃, the extruded material is excessively stretched so that the motion of the polymer chains is non-oriented. can

The first step of room temperature cooling may be performed to limit the movement of polymer chains to the maximum extent through a room temperature cooling process of the firstly stretched extruded discharged product. That is, the first room temperature cooling may be performed in order to maximally limit entanglement or twisting due to polymer motion in the drawing process of manufacturing commercial monofilaments. In addition, in order to proceed with the secondary stretching in a tensile tester having a limited vertical test space, it may be performed to shorten the extruded product cooled to room temperature to a certain length.

The first room temperature cooling may be performed for 1 to 10 minutes, preferably 2 to 8 minutes, more preferably 4 to 6 minutes, and most preferably 5 minutes. At this time, if the cooling time range at the first room temperature is not satisfied, it is difficult to effectively restrict the movement of the polymer chain, and entanglement or twisting may occur due to the movement of the polymer.

The first room temperature cooling may be performed in order to maximally limit entanglement or twisting caused by polymer motion in the drawing process of manufacturing commercial monofilaments. In addition, in order to proceed with the secondary elongation in a tensile tester having a limited vertical test space, it may be performed to shorten the extruded product cooled to room temperature to a certain length.

The secondary stretching may include cutting the extruded material cooled to room temperature to a length of 25 to 30 cm, fixing it to a grip having a distance between grips of 18 to 28 cm, and performing secondary stretching. The secondary stretched extruded material undergoes a temperature stabilization step for 2 to 7 minutes, and then the strain at which ductile fracture occurs at a tensile rate of 900 to 1300 mm/min at a temperature of 100 to 150 ° C is 90 to 95% Extension can be terminated. Preferably, after temperature stabilization for 4 to 6 minutes, it may be performed at a tensile rate of 950 to 1100 mm/min. At this time, when the strain rate is out of the above range, physical properties such as yarn strength, shrinkage rate, and crystallinity may be significantly deteriorated.

The secondary stretching may be performed at a temperature of 100 to 150 °C, preferably at a temperature of 110 to 120 °C. At this time, if the temperature of the secondary stretching is less than 100 ° C, the movement of polymer chains by thermal energy is small, and unstretched or primary stretched extrusion extrusion products may be cut off, and conversely, if it exceeds 150 ° C, torsional force As the chain is non-oriented and stretched, the yarn strength may decrease.

The step of preparing the polyolefin-based monofilament yarn may be prepared by secondarily cooling the secondarily drawn extruded material to room temperature. The secondary cooling at room temperature may be performed immediately after the end of the secondary stretching process while fixing the secondly stretched extruded material to the grip of a tensile tester to prevent thermal relaxation of the polymer chain.

In particular, although not explicitly described in the following Examples or Comparative Examples, etc., in the method for producing polyolefin-based monofilament yarn according to the present invention, the polyolefin-based monofilament yarn prepared by varying the following conditions is conventionally used. Durability, flexibility, transparency and toughness were further evaluated.

As a result, unlike the other conditions and different numerical ranges, it was confirmed that the physical properties of durability, flexibility, transparency and toughness were evenly excellent, unlike the existing polyolefin-based monoyarns, when all of the following 9 conditions were satisfied. By having these properties, it was found that it is suitable for application to stretched fibers, fishery ropes or fishing nets, and cords.

① the polyolefin-based resin composition includes 0.13 to 0.16 parts by weight of a rigid nucleating agent based on 100 parts by weight of a base resin containing 73 to 77% by weight of homopolypropylene and 23 to 27% by weight of high-density polyethylene, and ② the homopolypropylene is melted. The melt flow index (230 ℃, 2.16 kg) is 3 to 5 g / 10 min, ③ the high-density polyethylene has a density of 0.950 to 0.965 g / cm ³ , and the melt flow index (Melt Flow Index, 190 ℃, 2.16 kg) is 0.5 to 0.7 g/10 min, ④ the hard nucleating agent is sodium benzoate, ⑤ in the step of preparing the extruded product, the extrusion product has a diameter of 1.5 to 3.0 mm and a length of 10 to 20 cm, , ⑥ The first stretching step is to stretch the extruded material to a length of 20 to 30 cm at a temperature of 110 to 120 ℃, ⑦ The second stretching step is the first stretching at a temperature of 110 to 120 ℃ Stretching is terminated when the strain rate of the extruded material cooled at room temperature is 90 to 95%, ⑧ the polyolefin-based resin composition has a flexural modulus of 1450 to 1460 Mpa and a flexural strength of 38.8 to 38.9 Mpa measured according to ASTM D 790. And, the melting point is 162.7 to 162.9 ℃, ⑨ the polyolefin-based monofilament yarn has a draw ratio of 12 to 13, a fineness of 1800 to 1850 denier, and a tenacity measured according to ASTM D 638 of 9.7 to 10 gf/denier.

However, if any of the above 9 conditions is not satisfied, it is difficult to apply to elongated fibers, fishery ropes or fishing nets, or cords due to significantly reduced flexibility or reduced durability, transparency or toughness. Confirmed.

The polyolefin-based monofilament yarn may undergo Poisson shrinkage in which the cross section of the resin becomes uniformly small and strain hardening in which stress gradually increases due to stabilization of plasticity change when the yarn passes through the natural stretching period. In this process, the polymer chains bent in a lamellar shape within the destroyed spherulite may be aligned in a line in the stretching direction to form a microfibril structure.

In addition, a linear crystal starts to be generated in the microfiber structure by stress induced crystallization, and the orientation and crystallization of the polymer chain are important factors determining the strength of the mono yarn. After a specific deformation point in the strain hardening section, a stress-whitening phenomenon occurs. After the entangled polymer chains of the amorphous region connecting the fine fiber structures are released in the stretching direction, the fine fiber connecting molecules (Tie Molecules are cut off and a large number of pores (cavities) are created. The size of these pores gradually increases as stretching proceeds, and as a result, ductile fracture may eventually occur in the extruded product.

Therefore, in the present invention, plasticity change is stabilized by using a high-temperature tensile tester at a temperature of 100 to 150 ° C., and after the first high-temperature elongation is completed in the strain hardening step in which polymer chains are oriented in a row, the extruded product is fixed to the grip of the tensile tester and Polyolefin-based monofilament yarn is prepared by cooling it at room temperature, drawing it at a secondary high temperature, and then repeatedly cooling it at room temperature for the second time, so that the polymer chains oriented in the stretching direction are entangled by thermal relaxation or twisted in orientation It can stabilize the plasticity change without torsion.

In addition, the polyolefin-based monofilament yarn is capable of producing and copying highly-stretched polyolefin-based monofilament yarns in a short time by continuously performing multi-stage stretching and room temperature cooling processes of the polyolefin-based resin using a high-temperature tensile tester, and production of monofilament yarns is possible. There is an advantage that a large-scale stretching device is not required for the measurement, and the error due to the difference in measurement is small.

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited by the following examples.

Examples 1 to 5: Preparation of polyolefin resin composition

75% by weight of homopolypropylene having a melt flow index of 4.0 g/10min and 25% by weight of high-density polyethylene having a density of 0.952 g/cm ³ and a melt flow index of 0.6 g/10min A polyolefin resin composition was prepared by mixing sodium benzoate, a strong nucleating agent, with 100 parts by weight of the base resin in the mixing ratio shown in Table 1 below.

Examples 6 to 9: Preparation of polyolefin monofilament yarn (mono yarn)

Using the polyolefin resin compositions prepared in Examples 1 to 4 in turn, a monofilament yarn was produced by drawing in the following manner so as to have a draw ratio of 12.4: 1.

[stretching method]

The extruded material used in the tensile test was prepared using the polyolefin resin composition using a single-screw extruder and cutting machine manufactured by Tanabe Corporation VS40-NSIII. The extruder barrel temperature was 210 °C, 230 °C and 250 °C, respectively, and the rotational speed of the screw was 40 to 60 rpm. The extrudate discharged from this extruder passed through a cooling water bath at 25 to 35° C. and was taken out by a cutting machine at a constant speed of 5 to 15 m/min. The extruded material having a diameter of 1.5 to 3.0 mm passing through the cooling water tank was taken and cut into a length of 10 to 20 cm.

Using Shimadzu's AG-20Knxd high-temperature tensile tester, the extruded material having a diameter of 1.5 to 3.0 mm and a length of 10 to 20 cm was made into a mono yarn highly stretched 10 times or more using the high-temperature multi-stage stretching method according to the present invention. fabrication simulated. At this time, the extruded product is fixed to a grip having a distance between grips of the tensile tester of 6.5 to 7.5 cm, and after a temperature stabilization step for 5 minutes, a temperature of 110 ° C. at a tensile rate of 1000 mm / min until the strain hardening step The first elongation has been completed. Then, immediately after the end of the first stretching, the first room temperature cooling process was performed for 5 minutes while being fixed to the grip of the stretched extruded material.

After the room temperature cooling step, the extruded material first stretched from the grip of the tensile tester was cut to a length of 25 to 30 cm, and then fixed to a grip having a distance between grips of 18 to 28 cm. Then, after a temperature stabilization step for 5 minutes, the secondary stretching was terminated at 90 to 95% of the strain value at which ductile fracture occurs at a tensile rate of 1000 mm/min at a temperature of 110 °C. Immediately after the end of the second drawing, a second room temperature cooling step was performed for 5 minutes while being fixed to the grip of the drawn extrusion product, and then a polyolefin monofilament yarn (mono yarn), which is a secondly drawn extrusion product, was obtained.

Experimental Example 1: Evaluation of mechanical properties of polyolefin resin composition

In order to confirm the mechanical properties of the polyolefin resin compositions prepared in Examples 1 to 5, the flexural modulus and flexural strength according to ASTM D790 and the melting point were measured with a differential scanning calorimeter (DSC), and the results were Table 2 shows.

According to the results of Table 2, in the case of Examples 1 to 5, as the content of the rigid nucleating agent increased, the mechanical properties of flexural modulus and flexural strength improved, and in Example 5 containing 0.2 parts by weight of the rigid nucleating agent, the increase was further increased. It was confirmed that there was a slight decrease.

Experimental Example 2: Evaluation of abrasion resistance and yarn strength of monofilament yarn

For each of the monofilament yarns prepared in Examples 6 to 9, yarn strength according to ASTM D638 and abrasion resistance were measured by the following method, and the results are shown in Table 3 below.

[Abrasion resistance evaluation method]

Figure 2 is a photograph showing the abrasion tester device. The wear resistance evaluation according to FIG. 2 used a self-constructed wear measurement device. For the evaluation of wear resistance, the stroke of the serial reciprocating actuator was set to 150 mm, and the particle size was no. An abrasive stone of 220 was used. Then, a load of 200 g was applied to each monofilament specimen of Examples 6 to 9 stretched at 12.4: 1, a total of 600 reciprocating abrasion was performed at 50 rpm, and then the abrasion resistance was evaluated by the reduced weight.

According to the results of Table 3, in the case of Examples 6 to 9, as the content of sodium benzoate, a rigid nucleating agent, increased, the weight due to abrasion decreased, and in Example 9, it was confirmed that it was reduced by up to 15%.

Through this, when adjusting the content of the rigid nucleating agent, the size of the crystals in the resin composition is reduced so that the fine-sized crystals are evenly distributed, the interface between the base resin and the crystals is minimized, and phase separation is prevented to reduce the amount of wear during wear. confirmed that there is It was found that it is important to optimize the content of the rigid nucleating agent in order to apply this to a polyolefin-based elongated fiber or a polyolefin-based rope used for fishing rods or fishing nets.

10: Sample grips of a tensile tester with a distance between grips of 6.5 to 7.5 cm installed in a high-temperature oven
11: extrusion ejection with a diameter of 1.5 to 3.0 mm and a length of 10 to 15 cm
20: primary stretched extruded product
30: Extruded material cut to a certain length of 20 to 30 cm immediately after the first stretching
40: extruded ejection fixed in grips with a distance between grips of 18 to 28 cm
50: secondary stretched extruded material

Claims (10)

A polyolefin-based resin composition comprising 0.05 to 0.2 parts by weight of a rigid nucleating agent based on 100 parts by weight of a base resin containing 65 to 85% by weight of homo polypropylene and 15 to 35% by weight of high-density polyethylene is prepared at a temperature of 190 to 270 ° C. As a polyolefin-based monofilament yarn obtained by two-stage stretching of an extruded product obtained by extrusion with a twin-screw extruder with a high-temperature tensile tester,
The high-density polyethylene has a density of 0.910 to 0.980 g/cm ³ ,
The hard nucleating agent is sodium benzoate, sodium phosphate salt type or a mixture thereof;
The polyolefin-based monofilament yarn has a draw ratio of 9 to 14, a fineness of 1500 to 1900 denier, and a tenacity of 9 to 13 gf / denier measured according to ASTM D 638. filament yarn.
According to claim 1,
The homopolypropylene has a melt flow index (Melt Flow Index, 230 ° C, 2.16 kg) of 1 to 10 g / 10 min.
According to claim 1,
The high-density polyethylene has a melt flow index (Melt Flow Index, 190 ° C, 2.16 kg) of 0.1 to 5 g / 10 min. Polyolefin-based monofilament yarn.
According to claim 1,
The polyolefin-based resin composition has a flexural modulus of 1420 to 1470 Mpa, a flexural strength of 38.4 to 38.9 Mpa, and a melting point of 162.4 to 165 ° C., measured according to ASTM D 790.
A molded article made of the polyolefin-based monofilament yarn of any one of claims 1 to 4.
Preparing a polyolefin-based resin composition comprising 0.05 to 0.2 parts by weight of a rigid nucleating agent based on 100 parts by weight of a base resin containing 65 to 85% by weight of homo polypropylene and 15 to 35% by weight of high-density polyethylene;
Extruding the polyolefin-based resin composition at a temperature of 190 to 270 ° C. and then cutting to prepare an extruded product;
Injecting the extruded product into a high-temperature tensile tester and performing primary stretching at a temperature of 100 to 150 °C;
firstly cooling the firstly stretched extruded material to room temperature;
Secondary stretching at a temperature of 100 to 150 ° C. after cutting the first extruded material cooled to room temperature; and
Preparing a polyolefin-based monofilament yarn by secondarily cooling the secondarily drawn extruded discharge material to room temperature; Including,
The high-density polyethylene has a density of 0.910 to 0.980 g/cm ³ ,
The hard nucleating agent is sodium benzoate, sodium phosphate salt type or a mixture thereof;
The polyolefin-based monofilament yarn has a draw ratio of 9 to 14, a fineness of 1500 to 1900 denier, and a tenacity of 9 to 13 gf / denier measured according to ASTM D 638. Manufacturing method of filament yarn.
According to claim 6,
In the step of preparing the extruded discharged product, the extruded discharged product has a diameter of 1.5 to 3.0 mm and a length of 10 to 20 cm.
According to claim 6,
The primary stretching step is a method for producing a polyolefin-based monofilament yarn that is stretched so that the length of the extrusion discharge is 20 to 30 cm.
According to claim 6,
The secondary stretching step is a method for producing a polyolefin-based monofilament yarn that terminates the stretching when the strain rate of the extruded discharged product cooled to room temperature is 90 to 95%.
According to claim 6,
The polyolefin-based resin composition includes 0.13 to 0.16 parts by weight of a rigid nucleating agent based on 100 parts by weight of a base resin containing 73 to 77% by weight of homo polypropylene and 23 to 27% by weight of high-density polyethylene,
The homo polypropylene has a melt flow index (Melt Flow Index, 230 ° C, 2.16 kg) of 3 to 5 g / 10 min,
The high-density polyethylene has a density of 0.950 to 0.965 g/cm ³ , a melt flow index (190 °C, 2.16 kg) of 0.5 to 0.7 g/10min,
The hard nucleating agent is sodium benzoate;
In the step of preparing the extruded discharged product, the extruded discharged product has a diameter of 1.5 to 3.0 mm and a length of 10 to 20 cm,
The primary stretching step is to stretch the extruded material to a length of 20 to 30 cm at a temperature of 110 to 120 ° C.
The secondary stretching step is to end the stretching when the strain rate of the extruded product cooled to room temperature is 90 to 95% at a temperature of 110 to 120 ° C.
The polyolefin-based resin composition has a flexural modulus of 1450 to 1460 Mpa, a flexural strength of 38.8 to 38.9 Mpa, a melting point of 162.7 to 162.9 ° C, measured according to ASTM D 790,
The polyolefin-based monofilament yarn has a draw ratio of 12 to 13, a fineness of 1800 to 1850 denier, and a tenacity of 9.7 to 10 gf / denier measured according to ASTM D 638. Filament yarn manufacturing method.

Images