TWI855241B - High-strength polyamide 610 multifilament, ropes, racket strings, fabrics for bagging materials, fishing nets - Google Patents

Abstract

A high-strength polyamide 610 complex yarn, characterized by: a sulfuric acid relative viscosity of 3.0~3.7, and a dry strength of more than 9.2cN/dtex and less than 11.0cN/dtex. Provides high-strength polyamide 610 complex yarn.

Description

High-strength polyamide 610 multifilament, ropes, racket strings, packaging materials, fabrics, fishing nets

The present invention relates to a polyamide 610 multifilament having a higher strength than previous polyamide 610 multifilaments.

Compared with general-purpose multifilaments such as polyester or polypropylene, multifilaments of polyamide 6 or polyamide 66 have higher strength and elongation and superior fleece quality, so they can be used in many related applications such as airbags, tire curtains, racket strings, ropes, fishing nets, and bag straps. In the field of industrial materials, polyamide 6 and polyamide 66 have been used for many years from the perspective of high strength and elongation, high wear resistance, softness, and durability. Among them, polyamide 6 and polyamide 66 are generally polymers with water and moisture absorption. Therefore, in multifilaments of so-called general-purpose polyamides such as polyamide 6 or polyamide 66, the strength decreases due to water absorption or the dimensional changes due to moisture absorption are large. Therefore, there is a problem of reduced strength and reduced wear resistance due to water absorption.

On the other hand, as low water absorption polyamide multifilaments, multifilaments of polyamide 11, polyamide 610, and polyamide 612 are known, and are proposed as fibers for cleaning brushes, for example (Patent Document 1).

In addition, as a method for producing high-strength polyamide composite yarns required in the field of industrial materials, a method of adding a small amount of water to a polymer before melting has been proposed (Patent Document 2).

In order to obtain high-strength polyamide 6 or polyamide 66, it is necessary to increase the polymer viscosity and increase the elongation ratio. However, it is known that since high-viscosity polymers are rigid, the elongation is hindered near the high ratio. When mechanically forcibly elongated, the molecular chain is often cut, resulting in broken filaments, thereby reducing productivity. Therefore, as a method for stably obtaining high-strength polyamide yarns, it is proposed that when melt-spinning polyamide with a high viscosity relative to sulfuric acid to produce filaments, the water content of the polymer before melting is adjusted to a range of 0.04 wt% to 0.11 wt%.

The report states: In order to provide polyamide 610 multifilaments with sufficient strength for industrial material use based on the water addition technology for such general-purpose polyamide 6 and polyamide 66 polymers, a small amount of water is added to polyamide 610 fragments, thereby taking into account both the raw yarn strength of 8.5cN/dtex (centinewunk/dtex) required in the general industrial material field and good pile quality, and providing polyamide 610 multifilaments as low water absorption fibers for the industrial material field (patent document 3).

[Prior art literature]

[Patent Literature]

[Patent document 1] Japanese Patent Publication No. 2011-1635

[Patent document 2] Japanese Patent Publication No. 2014-214405

[Patent Document 3] International Publication No. 2019/163971

The polyamide multifilaments produced by the previous method disclosed in Patent Document 1 have lower strength and poorer fleece quality than polyamide 6 or polyamide 66, and therefore are difficult to expand to industrial material uses that require high-strength multifilaments.

In the technology disclosed in Patent Document 2, generally speaking, if water is added to the polymer before melting, the viscosity of the polymer immediately after melt ejection is reduced relative to the viscosity of the polymer before melting, so the desired high strength can be obtained by adjusting the manufacturing conditions such as the elongation ratio, and the elongation ratio decreases accordingly. As a result, it can be seen that the greater the water content of the polymer, the lower the elongation product (toughness) of the filament, the balance of the physical properties of the filament is destroyed, and good filaments with high strength and high elongation cannot be obtained. The practical appropriate water addition rate for polyamide 6 and polyamide 66 polymers is limited.

The technology disclosed in Patent Document 3 can be used to provide polyamide 610 multifilament to the field of industrial materials. However, in applications such as tire cords, ropes, and racket strings, which place particular emphasis on product strength and durability, higher multifilament requirements are required. Twisted yarn is strong. In order to bear the high strength of twisted yarn products by using multifilaments for general industrial materials, it is possible to consider increasing the number of parallel yarns to ensure the strength. However, there is a cost increase associated with an increase in the weight of the product or an increase in the number of multifilaments used. worry. Therefore, there is a demand for improving the strength of the multifilament itself. However, according to Patent Document 3, even if polyamide 610 multifilament suitable for general industrial materials can be provided, it is difficult to stably produce a strength exceeding 9 cN/dtex.

The subject of the present invention is to provide a high-strength, low-water-absorption polyamide composite that cannot be obtained by the prior art.

The inventors of the present invention have conducted diligent research to solve the above-mentioned problem, and the present invention includes the following structure.

(1) A high-strength polyamide 610 multifilament, characterized in that the relative viscosity of sulfuric acid is 3.0-3.7, and the strength when dry is greater than 9.2 cN/dtex and less than 11.0 cN/dtex.

(2) The high-strength polyamide 610 multifilament described in (1) is characterized in that the total fiber fineness is 100 dtex to 2500 dtex and the single fiber fineness is 1.5 dtex to 40 dtex.

(3) The high-strength polyamide 610 complex yarn as described in (1) or (2), wherein the birefringence Δn is greater than 50.0×10 ^-3 .

(4) The high-strength polyamide 610 complex yarn as described in any one of (1) to (3), characterized in that: the relative viscosity of sulfuric acid is 3.0-3.3, and the strength when dry is greater than 9.2 cN/dtex and less than 11.0 cN/dtex.

(5) The high-strength polyamide 610 multifilament described in any one of (1) to (4), characterized in that the change rate of strength, elongation and intermediate elongation when absorbing water is less than 10%.

(6) A rope characterized by using the high-strength polyamide 610 multifilament described in any one of (1) to (5).

(7) A racket string, characterized by using a high-strength polyamide 610 complex yarn as described in any one of (1) to (5).

(8) A fabric for bag material, characterized by using the high-strength polyamide 610 multifilament described in any one of (1) to (5).

(9) A fishing net characterized by using the high-strength polyamide 610 multifilament described in any one of (1) to (5).

According to the present invention, a polyamide 610 complex yarn exhibiting high strength can be provided which is realized by polyamide 6 or polyamide 66 complex yarn.

1: Spinning die opening

2: Heating tube

3: Cross-flow cooling device

4: Cooling wind

5: Silk thread

6: Pipeline

7: Oil supply device

8: Pulling roller

9: Pulling roller

10: First extension roller

11: Second extension roller

12: The third extension roller

13: Relaxation Roller

14: Entanglement endowment device

15: Winding machine (winding machine)

16: Fiber packaging

FIG1 is a schematic diagram of a direct spinning stretching device preferably used in the present invention.

The raw material fragments (hereinafter also referred to as fragments) of the high-strength polyamide 610 complex of the present invention are polyamide 610. It is preferred to include only polyamide 610, but in fact, it is sufficient to include polyamide 610. Within the range that does not damage the characteristics of the present invention, other polymers can be mixed within the range of 5% by mass or less, and copolymerization can also be performed. As the polymer/copolymer unit to be mixed or copolymerized, polyamides such as polyamide 6, polyamide 66, polyamide 11, and polyamide 12 are preferred.

The sulfuric acid relative viscosity (hereinafter referred to as viscosity) of the raw material fragments of the high-strength polyamide 610 multifilament of the present invention is preferably 3.6~4.0, more preferably 3.7~3.9, and further preferably 3.7~3.8. If the viscosity of the fragments is less than 3.6, when the moisture content of the fragments is set to the following preferred range, the viscosity of the polyamide 610 multifilament will be excessively reduced, and sometimes it is difficult to fully obtain the dry strength. In addition, if it exceeds 4.0, the melt viscosity of the polymer in the spinning machine will become higher, and the ejection property, spinnability or elongation from the die mouth will sometimes be impaired. In addition, the sulfuric acid relative viscosity refers to the value obtained by dissolving the sample in 98% sulfuric acid and measuring it at 25°C using an Ostwald viscometer.

The moisture content of the polyamide 610 fragments used as the raw material of the polyamide 610 multifilament of the present invention is preferably 0.15 wt % or more, more preferably 0.20 wt % to 0.35 wt %, and particularly preferably 0.25 wt % to 0.35 wt %. In order to obtain the high-strength polyamide 610 multifilament of the present invention, it is important to further improve the elongation by increasing the moisture content and reducing the melt viscosity compared with the previous technology. Furthermore, by the high water addition rate described above, water molecules invade the polyamide molecular chain and show a plasticizing effect, thereby greatly improving the elongation and achieving an increase in the ultimate elongation ratio. By these multiple effects, a high-strength polyamide 610 multifilament can be obtained. Furthermore, as a method for adjusting the moisture content, it is preferred to add a measured amount of water to the dried fragments and stir the fragments, but the method is not limited as long as the above range is achieved.

The sulfuric acid relative viscosity (hereinafter referred to as viscosity) of the high-strength polyamide 610 multifilament of the present invention needs to be 3.0~3.7, preferably 3.0~3.5, and further preferably 3.0~3.3. If the viscosity of the multifilament is less than 3.0, it is impossible to obtain a raw yarn with sufficient strength. If the viscosity exceeds 3.7, the elongation and pile quality may sometimes deteriorate.

In the use of tire curtains, ropes, and racket strings, the lightness of the product is important. Therefore, in order to meet the above requirements, the dry strength of the polyamide 610 multifilament of the present invention needs to be more than 9.2cN/dtex and within 11.0cN/dtex. More preferably, it is within 9.5cN/dtex~11.0cN/dtex.

It is difficult to produce high-strength fibers exceeding 9.2 cN/dtex using conventional methods, but by adjusting the high moisture content used in the present invention and achieving the following ranges of chip viscosity and multifilament viscosity, high-strength polyamide 610 multifilaments can be obtained.

The inventors have conducted diligent research and found that in order to obtain a high-strength polyamide 610 multifilament with a dry strength exceeding 9.2 cN/dtex, it is important to improve the elongation of the elongated portion compared to the previous technology and achieve a high-ratio elongation. Therefore, it was found that it is necessary to set the viscosity of the raw material chips to 3.6~4.0, the moisture content to 0.2 wt%~0.35 wt%, and the viscosity of the polyamide 610 multifilament to 3.0~3.7. Furthermore, in the case of polyamide 6 and polyamide 66, when the moisture content is 0.2 wt% or more, the water content in the polymer is excessive, and the equilibrium state of polymerization and decomposition of the polymer during the heating of the melt spinning shifts significantly to the decomposition side, the polymer decomposes, and the decrease in melt viscosity becomes greater. Thus, in order to ensure high strength, the elongation ratio of the extended part is set too high, resulting in a problem of reduced elongation and fuzzing due to increased mechanical load. On the other hand, in polyamide 610, surprisingly, although the phenomenon of reduced melt viscosity is the same, the elongation can be maintained even if the elongation ratio is set high, resulting in a high-strength, high-elongation multifilament. It is believed that this is because water molecules in polyamide 610 molecules act as plasticizers. In fact, high-strength polyamide 610 multifilaments that can achieve high-ratio elongation by adding water at a ratio of 0.2% to 0.35% by weight suggest that the orientation degree described later increases, and the elongation is improved due to the presence of water molecules.

The elongation is preferably 15% or more, and more preferably 17% or more. The quality of the fleece in the spinning step of polyamide 610 multifilament with an elongation of less than 15% is greatly deteriorated, and the number of broken yarns in the stretching step increases, so the productivity is sometimes poor.

The change rates of strength, elongation and intermediate elongation of the polyamide 610 multifilament of the present invention when absorbing water are preferably all less than 10%. More preferably, they are all less than 5%, and further preferably, they are all less than 2%. If the change rates of strength, elongation and intermediate elongation when absorbing water are less than 10%, the change of the strength-elongation curve, the so-called SS curve, when absorbing water can be suppressed compared with polyamide 6 or polyamide 66, which are general-purpose polyamides. This can suppress the reduction in strength of fiber products caused by water absorption due to outdoor rainfall or use at sea, and in addition, by suppressing the change of the SS curve, a product with excellent dimensional stability can be provided. This property is exhibited in polyamide 610 multifilament with low water absorption, and is an important property because maintaining product strength is one of the required properties, especially in high-strength applications. The change rate of these properties refers to the degree of change from the dry value to the water-absorbed value, and is a value measured using the method described below.

The total fiber density of the polyamide 610 multifilament of the present invention is preferably 100 dtex to 2500 dtex, and more preferably 100 dtex to 2000 dtex. If the total fiber density exceeds 2500 dtex, the amount of polymer ejected from the die becomes large, and the cooling of the yarn just after spinning is insufficient, and sometimes a multifilament with sufficient strength cannot be obtained.

As for the single fiber fineness, it is preferably 1.5dtex~40dtex, and more preferably 1.5dtex~15dtex. The polyamide 610 multifilament with a single fiber fineness of less than 1.5dtex has low wear resistance with the stretching roller in the spinning step, and when the stretching ratio is increased to obtain high-strength fibers, the quality of the pile may deteriorate. On the other hand, if it exceeds 40dtex, it becomes difficult to cool the polymer in the spinning step, and sometimes sufficient strength cannot be obtained.

The birefringence △n of the high-strength polyamide 610 complex of the present invention is preferably 50.0×10 ^-3 or more, and more preferably 52.0×10 ^-3 or more. The birefringence of the complex is an indicator of the molecular orientation, but it is believed that the high-strength polyamide 610 complex of the present invention has a sufficient amount of water molecules in the polyamide molecules by adding a high ratio of water to the raw material fragments, and the water molecules show a plasticizer effect, thereby improving the elongation. By improving the elongation, the mechanical stretching ratio can be increased, and the molecular orientation of the obtained complex, that is, the birefringence, is further increased. With regard to polyamide complexes, if the molecular orientation increases, the orientation crystallization also proceeds and increases gradually, so the strength of the complex is easily increased. In addition, birefringence Δn refers to a value measured using a polarizing microscope described later.

Next, the method for manufacturing the high-strength polyamide 610 multifilament of the present invention is described. The polyamide 610 multifilament can be preferably manufactured by the following method based on conventional melt spinning, but in the present invention, it is particularly effective to manufacture the polyamide 610 multifilament by direct spinning and drawing. In addition, when performing melt spinning, it is preferred to add a specified amount of water on the basis of managing the fragments to an appropriate viscosity, thereby increasing the strong elongation and suppressing the generation of broken yarns or fuzz during drawing, so that a high-strength polyamide 610 multifilament can be obtained as a result.

The following is an explanation using Figure 1 as an example.

FIG1 is a schematic diagram of a direct spinning stretching device preferably used in the present invention.

The polyamide 610 chips with adjusted viscosity, moisture content, etc. are melted and kneaded by an extruder-type spinning machine (not shown in FIG. 1 ), and then ejected from a spinning die 1 in a spinning section to be spun. The spinning temperature is generally set to a temperature that is 30°C or higher than the melting point of the target polymer. If the temperature is less than 30°C, the polymer cannot be uniformly melted due to insufficient heat, and the melt viscosity also increases, so the spinning property is unstable. The spun yarn 5 spun from the spinning die 1 passes through a heating cylinder 2 and is cooled by a cross-flow cooling device 3 using cooling air 4. The cooled wire 5 passes through the pipe 6, and is supplied with a treatment agent by the oil supply device 7, and is then pulled by the pulling roller 8. The pulled wire 5 is pre-stretched between the pulling rollers 8 and 9. After that, it is stretched in three stages by the first stretching roller 10, the second stretching roller 11, and the third stretching roller 12, and is relaxed by the relaxation roller 13. The relaxed wire 5 is wound by the winding imparting device 14, and is wound by the winding machine 15, thereby forming a fiber package 16.

As mentioned above, the viscosity of the polyamide 610 fragments used as raw materials is preferably 3.6~4.0, and the moisture content is preferably above 0.2% by weight.

The pulling speed during the pulling is 350m/min~1100m/min, preferably 400m/min~800m/min. The treatment agent in the present invention is preferably used as a non-aqueous treatment agent, and sufficient physical properties can be obtained even if an aqueous treatment agent is used. The treatment agent is preferably applied by an oiling roller device or guided oil supply.

The steps from stretching to winding are preferably a method of winding after two or more stages of stretching. When stretching is performed in two or more stages, it is preferably performed after pre-stretching. It is preferred that the pre-stretching and the first stage of stretching are performed by heat stretching before and after the glass transition temperature, and the remaining stretching and heat setting are usually performed at a high temperature of 150℃~220℃. More preferably, it is 170℃~210℃.

The stretching ratio, i.e., the ratio between the pulling roller 8 and the second stretching roller 11, is usually in the range of 3 to 6 times. Furthermore, the winding speed is usually preferably 2000m/min to 5000m/min, and more preferably 2000m/min to 4000m/min. In addition, it is preferred to use a winding device to roll the yarn into a flat tube under the condition of a winding tension of 20gf to 250gf.

The polyamide 610 complex of the present invention can be manufactured by the above method.

[Implementation example]

The present invention is described in detail below based on the embodiments, but the present invention is not limited to these embodiments. Furthermore, the measurement method of each measured value in the embodiments is as follows.

(1) Sulfuric acid relative viscosity (ηr): Take polymer fragments or filaments as samples, dissolve 0.25 g of the sample in 25 mL of 98% sulfuric acid, and measure it at 25°C using an Ostwald viscometer. The relative viscosity is calculated using the following formula. The measured value is calculated as the average value of five samples.

ηr = the number of seconds for the sample solution to flow down / the number of seconds for sulfuric acid to flow down.

(2) Moisture content: The measurement was performed by combining Hiranuma Sangyo's Hiranuma trace moisture measuring device "AQ-2200" and Hiranuma Sangyo's moisture vaporization device "EV-2000". That is, the moisture in the sample fragments was extracted using Hiranuma Sangyo's EV-2000, and the moisture content was measured using Hiranuma Sangyo's AQ-2200. The sample was set to 1.5g, and the nitrogen used for moisture vaporization was set to 0.2L/min.

The measurement conditions are as follows.

． Step 1: Temperature 210℃, time 21 minutes

． Drying time 0 minutes

．End B.G. 0μg

．Cooling time: 1 minute

． B.G. Stable times 30 times

． Reverse flushing time: 20 seconds.

(3) Total fiber density: Using JIS L1013 (2010) 8.3.1 A method, the positive fiber density is measured at a specified load of 0.045 cN/dtex and is set as the total fiber density.

(4) Number of filaments: Calculated using the method of JIS L1013 (2010) 8.4.

(5) Single fiber fineness: (3) total fineness divided by (4) number of filaments.

(6) (Dry) Strength/tensile strength/elongation: Measured according to JIS L1013 (2010) 8.5.1 under the constant elongation conditions shown in the standard test. The specimen was tested using the "TENSILON" UCT-100 manufactured by Orientech, with a clamp interval of 250 mm and a tensile speed of 300 mm/min. Strength and elongation were obtained from the maximum strength and maximum elongation of the S-S curve, and strength was obtained by dividing strength by total fiber density.

(Drying) Intermediate elongation: According to JIS L1017 (2002) 8.7a), using a reference fiber of 940 dtex, calculate the elongation under a constant load F (N) in the following formula as the intermediate elongation.

F=44×D/940

F: constant load (N), D: (3) total fiber density (dtex).

(7) (When absorbing water) Strength/tensile strength/elongation: According to the requirements of JIS L1013 (2010) 8.3.1 A method, small yarns of specified yarn length are made and immersed in tap water at 20°C for 24 hours. After 24 hours, the small yarns are taken out and measured under the constant speed elongation conditions shown in the JIS L1013 (2010) 8.5.1 standard test within 10 minutes. Strength and elongation are calculated from the maximum strength and maximum elongation of the S-S curve, and strength is calculated by dividing strength by total fiber density.

(When absorbing water) Intermediate elongation: According to JIS L1017 (2002) 8.7a), using a reference fiber of 940 dtex, calculate the elongation under a constant load F (N) in the following formula as the intermediate elongation.

F=44×D/940

F: constant load (N), D: (3) total fiber density (dtex)

For the strength when water absorbed, elongation when water absorbed, and intermediate elongation when water absorbed obtained by the measurement, the difference is taken from the values when dry, and the absolute values are divided by the strength when dry, elongation when dry, and intermediate elongation when dry, and expressed as percentages to calculate the change rate of strength when water absorbed, the change rate of elongation when water absorbed, and the change rate of intermediate elongation when water absorbed.

(8) Birefringence △n: The measurement is performed using a molecular orientation measuring device (Type: DELT_N-IIH) manufactured by INTEC. Wax is dripped onto a glass slide, a single filament of a filament is placed, and a cover glass is placed from the top. The glass slide is placed in a polarizing microscope and focused on both ends of the filament. A wavelength plate is inserted into the microscope and the wavelength λ that produces black fringes at both ends of the filament is adjusted. In this measurement, the wavelength plates are combined and adjusted to 2.5λ. The diameter D of the filament is then measured by image processing. Then the interval L between the two black interference fringes on both sides is measured.

In principle, it can be calculated by △n=R/d (R: optical path difference, d: transmission distance), but in this device, the optical path difference R is measured according to the wavelength of the wavelength plate, and the single wire diameter D and the interval L of the black interference fringe are measured by image processing, thereby automatically calculating △n.

[Implementation Example 1]

A 5 wt% aqueous solution of copper acetate was added as an antioxidant to the polyamide 610 (N610) fragments obtained by liquid phase polymerization, and 70 ppm of copper was added relative to the weight of the polymer for adsorption. Next, a 50 wt% aqueous solution of potassium iodide and a 20 wt% aqueous solution of potassium bromide were added in an amount of 0.1 wt% potassium relative to 100 wt% of the polymer fragments, and solid phase polymerization was performed using a solid phase polymerization device, followed by the addition of water to obtain polyamide 610 fragments with a sulfuric acid relative viscosity of 3.80 and a water content of 0.31 wt%.

As a spinning device, the device shown in FIG. 1 was used. The polyamide 610 chips were supplied to the extruder, and the ejection amount was adjusted by a metering pump so that the total fiber fineness was about 470 dtex. The spinning was carried out at a spinning temperature of 285°C, and after filtering with a metal nonwoven filter in a spinning pack, the spinning was carried out through a spinning die with a hole number of 48. The spun yarn passed through a heating cylinder heated to a temperature of 250°C and then cooled and solidified by cooling air at a wind speed of 40 m/min. The aqueous treatment agent is applied to the cooled and solidified yarn by the oil supply device 7, and the yarn is revolved to the spinning take-up roller and taken up. Thereafter, the taken-up yarn is temporarily not taken up and a 5% stretch is applied between the take-up roller 8 and the take-up roller 9, and then the first stage of stretching is performed between the take-up roller 9 and the first stretching roller 10 in such a manner that the rotation speed ratio between the rollers becomes 2.55, and then the second stage of stretching is performed between the first stretching roller 10 and the second stretching roller 11 in such a manner that the rotation speed ratio between the rollers becomes 1.35. Then, the third stretching is performed between the second stretching roller 11 and the third stretching roller 12 in such a way that the rotation speed ratio between the rollers becomes 1.65. The rotation speed ratio between the traction roller 8 and the third stretching roller 12 is set to 6.0.

Then, a 5% relaxation heat treatment is performed between the third stretching roller 12 and the relaxation roller 13, and the yarn is subjected to a winding treatment by the winding imparting device 14, and then the yarn is wound by the winding machine 15. The surface temperature of each roller is set such that the drawing roller is at room temperature, the yarn supply roller is 45°C, the first stretching roller is 95°C, the second stretching roller is 150°C, the third stretching roller is 200°C, and the relaxation roller is 140°C. The winding treatment is performed by spraying high-pressure air at right angles to the running yarn in the winding imparting device. Guides for controlling the traveling yarn were set before and after the winding imparting device, and the pressure of the sprayed air was fixed at 0.2MPa. Under the above conditions, polyamide 610 multifilament with a yarn density of 470dtex was obtained.

The obtained multifilament has very high elongation and can be stretched at a high ratio. The dry strength can reach 10.1 cN/dtex. The multifilament also has a high birefringence of 58.2, which indicates that the orientation crystallization in the multifilament is fully promoted. The strength change rate when absorbing water, the elongation change rate when absorbing water, and the intermediate elongation change rate when absorbing water are all less than 5%, and a multifilament with excellent dimensional stability and suppressed physical property degradation when absorbing water is obtained.

[Example 2]

The fragments were solid-phase polymerized using the same method as in Example 1, and water was added to obtain polyamide 610 fragments with a sulfuric acid relative viscosity of 3.80 and a water content of 0.25% by weight.

Except for adjusting the moisture content of the fragments, the same method as Example 1 was used for manufacturing.

Although the moisture content was set to 0.25% by weight, the obtained multifilament had very high elongation and could be stretched at a high rate. The dry strength was 10.0 cN/dtex. The birefringence of the multifilament was also high at 55.2, suggesting that the oriented crystallization in the multifilament was fully promoted. The evaluation results of the tensile test when absorbing water are shown in Table 1.

[Implementation Example 3]

The fragments were solid-phase polymerized using the same method as in Example 1, and water was added to obtain polyamide 610 fragments with a sulfuric acid relative viscosity of 3.80 and a water content of 0.21% by weight.

The third stretching is performed between the second stretching roller 11 and the third stretching roller 12 in such a way that the rotation speed ratio between the rollers becomes 1.59, and the rotation speed ratio between the traction roller 8 and the third stretching roller 12 is changed to 5.75. The same method as in Example 1 is used for manufacturing.

Although the moisture content was set to 0.21% by weight, the obtained multifilament had high elongation and could be stretched at a high rate. The dry strength was 9.8 cN/dtex. The birefringence of the multifilament was also high at 52.3, suggesting that the oriented crystallization in the multifilament was promoted. The evaluation results of the tensile test when absorbing water are shown in Table 1.

[Implementation Example 4]

The fragments were solid-phase polymerized using the same method as in Example 1, and water was added to obtain polyamide 610 fragments with a sulfuric acid relative viscosity of 3.80 and a water content of 0.25% by weight.

The third stretching is performed between the second stretching roller 11 and the third stretching roller 12 in such a way that the rotation speed ratio between the rollers becomes 1.59, and the rotation speed ratio between the traction roller 8 and the third stretching roller 12 is changed to 5.75. The same method as in Example 1 is used for manufacturing.

Although the moisture content was set to 0.25% by weight, the obtained multifilament had very high elongation and could be stretched at a high ratio. The dry strength was 9.6 cN/dtex. The multifilament also had a high birefringence of 53.8, suggesting that the oriented crystallization in the multifilament was fully promoted. The evaluation results of the tensile test when absorbing water are shown in Table 1.

[Implementation Example 5]

The fragments were solid-phase polymerized using the same method as in Example 1, and water was added to obtain polyamide 610 fragments with a sulfuric acid relative viscosity of 3.80 and a water content of 0.22% by weight.

The discharge volume is adjusted by a metering pump so that the total fiber density is about 970 dtex, and the yarn is spun through a spinning die with 204 holes.

The third stage of the stretching is performed between the second stretching roller 11 and the third stretching roller 12 in a manner that the rotation speed ratio between the rollers becomes 1.50, and the rotation speed ratio between the traction roller 8 and the third stretching roller 12 is changed to 5.42. The same method as in Example 1 is used for manufacturing.

Although the moisture content was set to 0.22% by weight, the total fiber density was set to 970 dtex, and the number of filaments was set to 204, the obtained multifilament had high elongation and could be stretched at a high rate. The dry strength was 9.4 cN/dtex. The birefringence of the multifilament was also high at 51.6, suggesting that the oriented crystallization in the multifilament was fully promoted. The evaluation results of the tensile test when absorbing water are shown in Table 1.

[Implementation Example 6]

The fragments were solid-phase polymerized using the same method as in Example 1, and water was added to obtain polyamide 610 fragments with a sulfuric acid relative viscosity of 3.79 and a water content of 0.15% by weight.

The third stretching is performed between the second stretching roller 11 and the third stretching roller 12 in a manner such that the rotation speed ratio between the rollers is 1.55, and the rotation speed ratio between the traction roller 8 and the third stretching roller 12 is changed to 5.60. The same method as in Example 1 is used for manufacturing.

Although the moisture content was set to 0.15% by weight, the obtained multifilament had high elongation and could be stretched at a high rate. The dry strength was 9.7 cN/dtex. The birefringence of the multifilament was also high at 52.0, suggesting that the oriented crystallization in the multifilament was fully promoted. The evaluation results of the tensile test when absorbing water are shown in Table 1.

[Implementation Example 7]

The fragments were solid-phase polymerized using the same method as in Example 1, and water was added to obtain polyamide 610 fragments with a sulfuric acid relative viscosity of 3.78 and a water content of 0.26% by weight.

The discharge volume is adjusted by a metering pump so that the total fiber density is about 235 dtex, and the yarn is spun through a spinning die with 136 holes.

The first stage of the stretching is performed between the traction roller 9 and the first stretching roller 10 in a manner that the rotation speed ratio between the rollers is 2.40, the second stage of the stretching is performed between the first stretching roller 10 and the second stretching roller 11 in a manner that the rotation speed ratio between the rollers is 1.35, and the third stage of the stretching is performed between the second stretching roller 11 and the third stretching roller 12 in a manner that the rotation speed ratio between the rollers is 1.41. The rotation speed ratio between the traction roller 8 and the third stretching roller 12 is changed to 4.80. The same method as in Example 1 is used for manufacturing.

Although the moisture content was set to 0.26% by weight, the total fiber density was set to 235 dtex, and the number of filaments was set to 136, the obtained multifilament had extremely high elongation and could be stretched at a high rate. The dry strength was 9.3 cN/dtex. The birefringence of the multifilament was also high at 54.2, suggesting that the oriented crystallization in the multifilament was fully promoted. The evaluation results of the tensile test when absorbing water are shown in Table 1.

[Implementation Example 8]

The fragments were solid-phase polymerized using the same method as in Example 1, and water was added to obtain polyamide 610 fragments with a sulfuric acid relative viscosity of 3.81 and a water content of 0.25% by weight.

The discharge volume is adjusted by a metering pump so that the total fiber density is about 1400 dtex, and the yarn is spun through a spinning die with 204 holes.

The first stage of the stretching is performed between the traction roller 9 and the first stretching roller 10 in a manner that the rotation speed ratio between the rollers is 2.70, the second stage of the stretching is performed between the first stretching roller 10 and the second stretching roller 11 in a manner that the rotation speed ratio between the rollers is 1.35, and the third stage of the stretching is performed between the second stretching roller 11 and the third stretching roller 12 in a manner that the rotation speed ratio between the rollers is 1.46. The same method as in Example 1 is used for manufacturing except that the rotation speed ratio between the traction roller 8 and the third stretching roller 12 is changed to 5.60.

Although the moisture content was set to 0.25% by weight, the total fiber density was set to 1400 dtex, and the number of filaments was set to 204, the obtained multifilament had high elongation and could be stretched at a high rate. The dry strength was 9.3 cN/dtex. The birefringence of the multifilament was also high at 51.3, suggesting that the oriented crystallization in the multifilament was fully promoted. The evaluation results of the tensile test when absorbing water are shown in Table 1.

[Comparison Example 1]

The fragments were solid-phase polymerized using the same method as in Example 1, and water was added to obtain polyamide 610 fragments with a sulfuric acid relative viscosity of 3.82 and a water content of 0.05% by weight.

The polyamide 610 fragments are supplied to the extruder in the same manner as in Example 1, and the ejection amount is adjusted by a metering pump so that the total fiber density is about 470 dtex. The spinning is carried out at a spinning temperature of 285°C, and after filtering with a metal non-woven filter in the spinning assembly, the spinning is carried out through a spinning die with a hole number of 48. The spun yarn passes through a heating cylinder heated to a temperature of 250°C and is cooled and solidified by cooling air at a wind speed of 40m/min. The aqueous treatment agent is applied to the cooled and solidified yarn by an oil supply device 7, and the yarn is swung back to the spinning take-up roller and the yarn is drawn. After that, the pulled yarn is temporarily not wound and a 5% stretch is applied between the pulling roller 8 and the pulling roller 9, and then the first stretching is performed between the pulling roller 9 and the first stretching roller 10 in a manner that the rotation speed ratio between the rollers becomes 2.55, and then the second stretching is performed between the first stretching roller 10 and the second stretching roller 11 in a manner that the rotation speed ratio between the rollers becomes 1.35. Then, the third stretching is performed between the second stretching roller 11 and the third stretching roller 12 in a manner that the rotation speed ratio between the rollers becomes 1.35. The rotation speed ratio between the pulling roller 8 and the third stretching roller 12 is set to 4.9.

Then, a 5% relaxation heat treatment is performed between the third stretching roller 12 and the relaxation roller 13, and the yarn is subjected to a winding treatment by the winding imparting device 14, and then the yarn is wound by the winding machine 15. The surface temperature of each roller is set such that the drawing roller is at room temperature, the yarn supply roller is 45°C, the first stretching roller is 95°C, the second stretching roller is 150°C, the third stretching roller is 200°C, and the relaxation roller is 140°C. The winding treatment is performed by spraying high-pressure air at right angles to the running yarn in the winding imparting device. Guides for controlling the traveling yarn were set before and after the winding imparting device, and the pressure of the sprayed air was fixed at 0.2MPa. Under the above conditions, polyamide 610 multifilament with a yarn density of 470dtex was obtained.

The obtained multifilament has insufficient elongation, and the limit of the rotation speed ratio between the drawing roll 8 and the third stretching roll 12 is about 5 times. The strength during drying is limited to about 8.8 cN/dtex. It was confirmed that the birefringence of the multifilament is also 47.0, which is lower than the multifilament of the present invention. The evaluation results of the tensile test during water absorption are shown in Table 2.

[Comparison Example 2]

The fragments were solid-phase polymerized using the same method as in Example 1 without adding water. The sulfuric acid relative viscosity of the obtained polyamide 610 fragments was 3.82, and the moisture content was 0.02% by weight.

The same method as in Comparative Example 1 was used for manufacturing except that the moisture content of the chips was changed.

The obtained multifilament has insufficient elongation, and the upper limit of the rotation speed ratio between the drawing roller 8 and the third stretching roller 12 is about 5 times. The strength during drying is limited to about 8.9 cN/dtex.

The produced guide was set up, and the pressure of the sprayed air was fixed at 0.2 MPa. Under the above conditions, a polyamide 610 multifilament of 470 dtex was obtained. It was confirmed that the birefringence of the multifilament was also 47.2, which was lower than that of the multifilament of the present invention. The evaluation results of the tensile test during water absorption are shown in Table 2.

[Comparison Example 3]

The fragments were solid-phase polymerized using the same method as in Example 1 without adding water. The sulfuric acid relative viscosity of the obtained polyamide 610 fragments was 4.00 and the moisture content was 0.02% by weight.

The third stretching is performed between the second stretching roller 11 and the third stretching roller 12 in a manner such that the rotation speed ratio between the rollers becomes 1.24, and the rotation speed ratio between the traction roller 8 and the third stretching roller 12 is changed to 4.50. The same method as in Example 1 is used for manufacturing.

The obtained multifilament has poor elongation, and the limit of the rotation speed ratio between the drawing roller 8 and the third stretching roller 12 is about 4.5 times. The strength during drying is limited to about 8.3cN/dtex, and the quality of the pile is also poor. It is confirmed that the birefringence of the multifilament is also 46.3, which is lower than the multifilament of the present invention. The evaluation results of the tensile test during water absorption are shown in Table 2.

[Comparison Example 4]

The fragments obtained by liquid phase polymerization were changed from polyamide 610 fragments to polyamide 6 fragments, and a 5 wt% aqueous solution of copper acetate was added as an antioxidant for mixing, and 70 ppm of copper was added relative to the weight of the polymer for adsorption. Next, a 50 wt% aqueous solution of potassium iodide and a 20 wt% aqueous solution of potassium bromide were added in an amount of 0.1 wt% potassium relative to 100 wt% of the polymer fragments, and solid phase polymerization was performed using a solid phase polymerization device, and water was added to obtain polyamide 6 fragments with a sulfuric acid relative viscosity of 3.80 and a water content of 0.05 wt%.

The polyamide 6 fragments are supplied to the extruder in the same manner as in Example 1, and the ejection amount is adjusted by a metering pump so that the total fiber density is about 2100 dtex. The spinning is carried out at a spinning temperature of 285°C, and after filtering with a metal nonwoven filter in the spinning assembly, the spinning is carried out through a spinning die with a hole number of 306. The spun yarn passes through a heating cylinder heated to a temperature of 315°C and is cooled and solidified by cooling air at a wind speed of 35m/min. The aqueous treatment agent is applied to the cooled and solidified yarn by an oil supply device 7, and the yarn is swung to the spinning take-up roller and the yarn is drawn. After that, the pulled yarn is temporarily not wound and a 7% stretch is applied between the pulling roller 8 and the pulling roller 9, and then the first stretching is performed between the pulling roller 9 and the first stretching roller 10 in a manner that the rotation speed ratio between the rollers becomes 2.90, and then the second stretching is performed between the first stretching roller 10 and the second stretching roller 11 in a manner that the rotation speed ratio between the rollers becomes 1.50. Then, the third stretching is performed between the second stretching roller 11 and the third stretching roller 12 in a manner that the rotation speed ratio between the rollers becomes 1.15. The rotation speed ratio between the pulling roller 8 and the third stretching roller 12 is set to 5.37.

Then, a relaxation heat treatment of 8% is performed between the third stretching roller 12 and the relaxation roller 13, and the yarn is subjected to a winding treatment by the winding imparting device 14, and then the yarn is wound by the winding machine 15. The surface temperature of each roller is set such that the drawing roller is at room temperature, the yarn supply roller is 45°C, the first stretching roller is 105°C, the second stretching roller is 180°C, the third stretching roller is 200°C, and the relaxation roller is 145°C. The winding treatment is performed by spraying high-pressure air at right angles to the running yarn in the winding imparting device. Guides for controlling the traveling yarn were set before and after the winding imparting device, and the pressure of the sprayed air was fixed at 0.3MPa. Under the above conditions, polyamide 6 multifilament with a density of 2100dtex was obtained.

Regarding the extensibility of the obtained multifilament, the limit of the rotation speed ratio between the drawing roll 8 and the third stretching roll 12 is about 5.6 times. At this time, the strength during drying is limited to about 9.2 cN/dtex. It was confirmed that the birefringence of the multifilament was also 48.2, which is lower than the polyamide 610 multifilament of the present invention. The evaluation results of the tensile test during water absorption are shown in Table 2. Since it is a polyamide 6 multifilament, the strength decreases greatly during water absorption.

1: Spinning die opening

2: Heating tube

3: Cross-flow cooling device

4: Cooling wind

5: Silk thread

6: Pipeline

7: Oil supply device

8: Pulling roller

9: Pulling roller

10: First extension roller

11: Second extension roller

12: Third extension roller

13: Relaxation Roller

14: Entanglement endowment device

15: Winding machine (winding machine)

16: Fiber packaging

Claims (9)

A high-strength polyamide 610 complex yarn is characterized in that it is produced by melt-spinning polyamide 610 raw material fragments having a sulfuric acid relative viscosity of 3.6-4.0 and a moisture content of 0.20 wt%-0.35 wt%, and stretching them at a stretching ratio of 3 to 6 times, and the sulfuric acid relative viscosity is 3.0-3.7, and the strength when dry exceeds 9.2 cN/dtex and is within 11.0 cN/dtex. The high-strength polyamide 610 multifilament as described in claim 1, wherein the total fiber density is 100 dtex to 2500 dtex and the single fiber fiber density is 1.5 dtex to 40 dtex. The high-strength polyamide 610 complex as described in claim 1 or claim 2, wherein the birefringence Δn is greater than 50.0×10 ^-3 . The high-strength polyamide 610 complex yarn as described in claim 1 or claim 2, wherein the relative viscosity of sulfuric acid is 3.0-3.3, and the strength when dry exceeds 9.2 cN/dtex and is within 11.0 cN/dtex. The high-strength polyamide 610 multifilament as described in claim 1 or claim 2, wherein the change rate of strength, elongation and intermediate elongation when absorbing water is less than 10%. A rope characterized by using the high-strength polyamide 610 complex yarn as described in any one of claims 1 to 5. A racket string, characterized by using the high-strength polyamide 610 complex yarn as described in any one of claim 1 to claim 5. A fabric for packaging material, characterized by using the high-strength polyamide 610 complex yarn as described in any one of claim 1 to claim 5. A fishing net characterized by using the high-strength polyamide 610 complex yarn as described in any one of claims 1 to 5.

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