High resilience and anti-creep copolyamide monofilament, its preparation method and application

Abstract

The present application discloses a high resilience and anti-creep copolymerized nylon monofilament, its preparation method and application. The inorganic nanoparticles are surface-modified by a silane coupling agent. After the modified nanoparticles are uniformly mixed with the copolymerized polyamide, they are added to a twin-screw extruder for melt blending and extrusion. The melt-extruded filament is cooled by a coolant to form a nascent filament. The nascent filament is subjected to two-stage stretching and then to a setting treatment. According to the technical solution provided by the embodiments of the present application, by providing inorganic nanoparticles and surface-modifying the inorganic nanoparticles with a silane coupling agent, the surface effect of the nanoparticles is improved, and the dispersibility of the nanoparticles in the polymer matrix is improved. At the same time, the terminal epoxy group of the coupling agent also undergoes a graft copolymerization reaction with the amino group of the copolymerized polyamide, extending the molecular chain of the polyamide, greatly restricting the movement of the molecular chain, and further reducing the creep effect of the polymer monofilament.

Description

Technical Field

[0001] The present invention generally relates to the field of monofilaments, and in particular to high resilience and creep-resistant copolyamide monofilaments and their preparation methods and applications. Background Art

[0002] The use of copolyamide PA6 / 66 monofilaments as fishing lines requires meeting the following several indicators: high transparency, good softness, high strength, and good toughness. To achieve this goal, there have been many related studies. For example, simply using inorganic nano-additives and polyamide for melt blending. Since inorganic nano-particles are prone to agglomeration in the polymer matrix and agglomerate into larger particles, it not only fails to improve the resilience but instead becomes a stress concentration point, reducing its original performance. In addition, there are many studies using organic nucleating agents, plasticizers, etc. to modify. It is very difficult to obtain a monofilament product with high strength, good softness and smoothness, good resilience, and good transparency by adding these additives. Summary of the Invention

[0003] In view of the above-mentioned defects or deficiencies in the prior art, it is desired to provide a high resilience and creep-resistant copolyamide monofilament and its preparation method and application.

[0004] In the first aspect, a preparation method of a high resilience and creep-resistant copolyamide monofilament is provided, including the steps:

[0005] S10: Provide inorganic nano-particles, and perform surface modification on the inorganic nano-particles through a silane coupling agent to form modified nano-particles.

[0006] S20: After uniformly mixing the modified nano-particles with copolyamide, add them into a twin-screw extruder for melt blending and extrusion. The mass fraction of the modified nano-particles is 1-2, and the mass fraction of the copolyamide is 98-99.

[0007] S30: The melt-extruded filament is cooled by a coolant, the temperature of the coolant is less than or equal to 0 °C, and then it is drawn and wound to form a primary filament.

[0008] S40: Perform two-stage stretching on the primary filament. The first stage stretching is steam stretching, and the stretching ratio is 3-4 times. The second stage stretching is hot air stretching, and the stretching ratio is 1.1-1.5 times. Then perform a setting treatment to form a high resilience and creep-resistant copolyamide monofilament.

[0009] In the second aspect, a copolyamide monofilament prepared by the above-mentioned preparation method of a high resilience and creep-resistant copolyamide monofilament is provided.

[0010] In the third aspect, an application of the above copolyamide monofilament is provided.

[0011] According to the technical solution provided by the embodiments of the present application, by providing inorganic nanoparticles and surface-modifying the inorganic nanoparticles with a silane coupling agent, the surface effect of the nanoparticles is improved, and the dispersibility of the nanoparticles in the polymer matrix is improved. At the same time, the terminal epoxy group of the coupling agent also undergoes a graft copolymerization reaction with the amino group of the copolyamide, extending the molecular chain of the polyamide, greatly restricting the movement of the molecular chain, further reducing the creep effect of the polymer monofilament, thereby improving the elastic recovery rate of the fiber and obtaining a high-elasticity nylon monofilament. Description of the Drawings

[0012] Other features, objects, and advantages of the present application will become more apparent by reading the detailed description of the non-limiting embodiments with reference to the following drawings:

[0013] Figure 1 It is a flow chart of the preparation method of the high-elasticity and creep-resistant copolyamide monofilament in this embodiment. Detailed Embodiments

[0014] The present application will be further described in detail below with reference to the drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the related invention and are not intended to limit the invention. In addition, it should be noted that only the parts related to the invention are shown in the drawings for the convenience of description.

[0015] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The present application will be described in detail below with reference to the drawings and embodiments.

[0016] Please refer to Figure 1 , this embodiment provides a method for preparing a high-elasticity and creep-resistant copolyamide monofilament, including the steps of:

[0017] S10: Provide inorganic nanoparticles, and surface-modify the inorganic nanoparticles with a silane coupling agent to form modified nanoparticles.

[0018] S20: After uniformly mixing the modified nanoparticles with the copolyamide, add them to a twin-screw extruder for melt blending and extrusion. The mass fraction of the modified nanoparticles is 1-2, and the mass fraction of the copolyamide is 98-99.

[0019] S30: The melt-extruded filament is cooled by a coolant, the temperature of the coolant is less than or equal to 0 °C, and then it is drawn and wound to form a primary filament.

[0020] S40: Perform two-stage stretching on the primary filament. The first stage of stretching is steam stretching, and the stretching ratio is 3-4 times. The second stage of stretching is hot air stretching, and the stretching ratio is 1.1-1.5 times. Then, perform a shaping treatment to form a high-elasticity and creep-resistant copolyamide monofilament.

[0021] In this embodiment, by providing inorganic nanoparticles and surface-modifying the inorganic nanoparticles with a silane coupling agent, the surface effect of the nanoparticles is improved, and the dispersibility of the nanoparticles in the polymer matrix is improved. At the same time, the terminal epoxy group of the coupling agent also undergoes a graft copolymerization reaction with the amino group of the copolyamide, extending the molecular chain of the polyamide, greatly restricting the movement of the molecular chain, further reducing the creep effect of the polymer monofilament, thereby improving the elastic recovery rate of the fiber and obtaining a high-elasticity nylon monofilament.

[0022] First, an inorganic nanoparticle is provided, and the inorganic nanoparticle is surface-modified with a silane coupling agent. Among them, the selected inorganic nanoparticle is a spherical particle, a rod-shaped particle, or a layered particle. The shape of the selected nanoparticle has no necessary connection with the operation steps, and different shapes are feasible.

[0023] Optionally, the inorganic nanoparticle is one or more of inorganic nano-TiO2, inorganic nano-SiO2, nano-CaCO3, nano-whiskers, nano-attapulgite, silicate, vermiculite. In this embodiment, inorganic nano-materials are selected for surface modification. There are various inorganic nano-materials available. Preferably, one or more of the above are used. The dispersibility of the inorganic nanoparticles in the polymer matrix is improved through a silane coupling agent, so that the modified inorganic nanoparticles can be fully dispersed in the copolyamide, fully mixed with the copolyamide, and react with it.

[0024] Specifically, the surface modification of the inorganic nanoparticles includes:

[0025] S11: The inorganic nanoparticles are fully mixed with an ethanol solution with a mass fraction of 75%, and the mass ratio of the inorganic nanoparticles to the ethanol solution is 5-10:100;

[0026] S12: The silane coupling agent is added to the mixed solution, and the pH value of the mixed solution is adjusted to 7-9 with sodium hydroxide. The addition amount of the silane coupling agent is 1-3% of the mass of the inorganic nanoparticles;

[0027] S13: The mixed solution is heated to 75-85°C, kept warm and stirred for 6-8 hours;

[0028] S14: The mixed solution after heat preservation is centrifuged to obtain modified nanoparticles.

[0029] The inorganic nanoparticles are fully mixed with an ethanol solution whose solvent is water. Subsequently, a silane coupling agent is added, and the pH value is adjusted by adding sodium hydroxide. After adjustment, it is stirred evenly to obtain a first mixed solution. Subsequently, the first mixed solution is heated in a way of slowly increasing the temperature. After heat preservation and stirring for a period of time, a second mixed solution is obtained. Since the silane coupling agent is easily grafted onto the nanoparticles in an alkaline environment and the grafting rate is the highest, modified nanoparticles with the highest grafting rate are obtained.

[0030] The second mixed solution is centrifuged to obtain the solid, which is the modified nanomaterial. After obtaining the solid product, drying and grinding are still required. The modified nanoparticles are ground to the required particle size to make their distribution more uniform in the copolyamide.

[0031] Furthermore, the silane coupling agent is one of KH550, KH560, and KH570. In this embodiment, a relatively large variety of silane coupling agents are selected. However, different silane coupling agents have different surface modification effects on inorganic nanoparticles. For example, when KH560 is selected as the coupling agent, the end group of this coupling agent is an epoxy group, which can improve the surface effect of the nanoparticles and the dispersibility of the nanoparticles in the polymer matrix. At the same time, the end-group epoxy group of KH560 also undergoes a graft copolymerization reaction with the amino group of the copolyamide, extending the molecular chain of the polyamide, greatly restricting the movement of the molecular chain, and further reducing the creep effect of the polymer monofilament, thereby improving the elastic recovery rate of the fiber. When KH550 is selected as the coupling agent, the end-group of this coupling agent is an amino group, which forms a hydrogen bond with the terminal hydroxyl group of the polyamide, and it can also achieve the role of surface modification. However, the hydrogen bond force is not as strong as the covalent bond force, and the effect of the product produced is slightly worse than that modified by the coupling agent KH560. Therefore, preferably, KH560 is used as the silane coupling agent for surface modification.

[0032] Preferably, the viscosity of the copolyamide is 2.4 - 3.2. The viscosity of the copolyamide in this embodiment is beneficial to the formation of high-strength and high-elasticity-recovery monofilaments.

[0033] Preferably, the above-mentioned inorganic nanoparticles are SiO 2 particles, and the silane coupling agent is KH560 coupling agent. The following chemical formula shows the modification of SiO2 by the coupling agent KH560, making the end group of SiO 2 particles modified to an epoxy group and undergoing a graft copolymerization reaction with the copolyamide.

[0034]

[0035] Subsequently, the particles of the modified nanoparticles are uniformly mixed with the copolyamide, and then added to a twin-screw extruder for melt blending and extrusion. In this embodiment, the outlet of the twin-screw extruder used is conical, and the screw temperature is 235-255 °C;

[0036] The filaments obtained by melt extrusion need to be cooled by a coolant. Preferably, the temperature of the coolant is set to be less than or equal to 0 °C. By quenching with this coolant, the filaments ejected hardly crystallize in the coolant and maintain an unstable crystal structure, which is more convenient for the subsequent stretching process and can finally obtain a copolyamide monofilament product with high strength, high elastic recovery rate, good transparency, and high softness and smoothness. In this embodiment, an alcohol solution, such as ethanol, is preferably used as the coolant.

[0037] The as-formed primary filaments are subjected to two-stage stretching. The first stage is steam stretching. The primary filaments are stretched through a steam water tank at 100 °C, and the stretching ratio is 3-4 times. The second stage is hot air stretching. The filaments are stretched through a hot air stretching oven, and the temperature is set to 150-200 °C, and the stretching ratio is 1.1-1.5 times. Finally, a setting treatment is carried out at a temperature of 150-210 °C to obtain a copolyamide monofilament product, which is then wound up and stored.

[0038] This embodiment also provides a high-elasticity and creep-resistant copolyamide monofilament prepared by the above method. This monofilament has the characteristics of high strength, high elastic recovery rate, good transparency, and high softness and smoothness.

[0039] The above copolyamide monofilament is applied to a fishing line. When used as a fishing line, it can meet the characteristics of good softness, high strength, and good toughness.

[0040] According to the above method, three examples and nine comparative examples are given below, and tests on the single-filament breaking strength, single-filament elongation, knotting ratio, and elastic recovery rate of the examples and comparative examples are carried out:

[0041] Example 1:

[0042] Step 1. Surface modification treatment of inorganic nano-SiO2

[0043] Nano-SiO2 and an ethanol solution with a mass fraction of 75% (the solvent is water) are added to a reaction kettle. The mass ratio of the two is 5:100 and they are fully mixed. Then KH560 is added, and the addition amount is 1% of the mass fraction of nano-SiO2. The pH value is adjusted to 7-9 and stirred evenly to obtain a mixed system A. Then the temperature is slowly raised to 75-85 °C, and it is kept warm and stirred for 6 hours to obtain a mixed system B. The mixed system B is centrifuged to obtain a product C, which is then cooled, dried, and ground to obtain modified nano-SiO2 with a particle size of 10-20 μm.

[0044] Step 2: Copolymerization grafting reaction of modified nano-SiO₂ and copolyamide

[0045] The modified nano-SiO₂ powder particles obtained in Step 1, with a content of 1%, and copolyamide PA6 / 66 with a content of 99% are first mixed at high speed in a high-speed mixer, and then added together to a conical twin-screw extruder for melt blending and extrusion. The screw temperature is 255 °C, the spinneret specification is 0.8*32H, the metering pump speed is 8 r / min, and then it passes through a high-boiling-point alcohol solution with a coolant temperature of -10 °C for quenching, then through a drawing machine, and then wound up to obtain a nascent filament. Then the obtained nascent filament passes through a steam water bath at 100 °C for single-stage drawing, with a single-stage drawing ratio of 5 times, and then through a hot air drawing oven with a temperature set at 180 °C, and a two-stage drawing ratio of 1.25 times. Finally, it is subjected to setting treatment and wound up to obtain a PA6 / 66 monofilament product, and the setting treatment temperature is 200 °C.

[0046] Example 2:

[0047] Step 1: Surface modification treatment of inorganic nano-SiO₂

[0048] Nano-SiO₂ and an ethanol solution with a mass fraction of 75% (solvent is water) are added to a reaction kettle, and their mass ratio is 8:100 and fully mixed. Then KH550 is added, and the addition amount is 2% of the mass fraction of nano-SiO₂. After adjusting the pH value to 7 - 9 and stirring evenly, a mixed system A is obtained. Then it is slowly heated to 75 - 85 °C, kept warm and stirred for 7 hours to obtain a mixed system B. The mixed system B is centrifuged to obtain a product C, then cooled, dried, and ground to obtain modified nano-SiO₂ with a particle size of 10 - 20 μm. Step 2. Copolymerization grafting reaction of modified nano-SiO₂ and copolyamide

[0049] Step 2: Copolymerization grafting reaction of modified nano-SiO₂ and copolyamide

[0050] The modified nano-SiO₂ powder particles obtained in Step 1, with a content of 1.5%, and the copolyamide PA6 / 66 with a content of 98.5% are first mixed at high speed in a high-speed mixer, and then added together into a conical twin-screw extruder for melt blending and extrusion. The screw temperature is 255 °C, the spinneret specification is 0.8*32H, the metering pump speed is 8 r / min, and then it passes through a high-boiling-point alcohol solution with a coolant temperature of -10 °C for quenching, then through a drawing machine, and then wound up to obtain a nascent filament. Then, the obtained nascent filament passes through a steam water tank at 100 °C for a first drawing, and the first drawing ratio is 5 times. Then, it passes through a hot air drawing oven with a temperature set at 180 °C, and the second drawing ratio is 1.25 times. Finally, it is subjected to shaping treatment and wound up to obtain a PA6 / 66 monofilament product, and the shaping treatment temperature is 200 °C.

[0051] Example 3:

[0052] Step 1. Surface modification treatment of inorganic nano-SiO₂

[0053] Nano-SiO₂ and an ethanol solution with a mass fraction of 75% (the solvent is water) are added to a reaction kettle, and the mass ratio of the two is 10:100 and fully mixed. Then, KH570 is added, and the addition amount is 3% of the mass fraction of nano-SiO₂. After adjusting the pH value to 7 - 9 and stirring evenly, a mixed system A is obtained. Then, it is slowly heated to 75 - 85 °C, kept warm and stirred for 8 hours to obtain a mixed system B. The mixed system B is centrifuged to obtain a product C, then cooled, dried, and ground to obtain modified nano-SiO₂ with a particle size of 10 - 20 μm. Step 2. Copolymerization grafting reaction of modified nano-SiO₂ and copolyamide

[0054] Step 2. Copolymerization grafting reaction of modified nano-SiO₂ and copolyamide

[0055] The modified nano-SiO₂ powder particles obtained in Step 1, with a content of 2%, and the copolyamide PA6 / 66 with a content of 98% are first mixed at high speed in a high-speed mixer, and then added together into a conical twin-screw extruder for melt blending and extrusion. The screw temperature is 255 °C, the spinneret specification is 0.8*32H, the metering pump speed is 8 r / min, and then it passes through a high-boiling-point alcohol solution with a coolant temperature of -10 °C for quenching, then through a drawing machine, and then wound up to obtain a nascent filament. Then, the obtained nascent filament passes through a steam water tank at 100 °C for a first drawing, and the first drawing ratio is 5 times. Then, it passes through a hot air drawing oven with a temperature set at 180 °C, and the second drawing ratio is 1.25 times. Finally, it is subjected to shaping treatment and wound up to obtain a PA6 / 66 monofilament product, and the shaping treatment temperature is 200 °C.

[0056] Comparative Example 1:

[0057] In Step 1, the mass ratio of nano-SiO2 to the ethanol solution is 3:100, and other process conditions are the same as those in Example 1.

[0058] Comparative Example 2:

[0059] In Step 1, the mass ratio of nano-SiO2 to the ethanol solution is 15:100, and other process conditions are the same as those in Example 1.

[0060] Comparative Example 3:

[0061] In Step 1, the coupling agent added is a titanate coupling agent, and other process conditions are the same as those in Example 1.

[0062] Comparative Example 4:

[0063] In Step 1, the amount of KH550 added is 0.5% of the mass fraction of nano-SiO2, and other process conditions are the same as those in Example 1.

[0064] Comparative Example 5:

[0065] In Step 1, the amount of KH550 added is 4% of the mass fraction of nano-SiO2, and other process conditions are the same as those in Example 1.

[0066] Comparative Example 6:

[0067] In Step 1, the stirring reaction time is 5 hours, and other process conditions are the same as those in Example 1.

[0068] Comparative Example 7:

[0069] In Step 1, the stirring reaction time is 10 hours, and other process conditions are the same as those in Example 1.

[0070] Comparative Example 8:

[0071] In Step 2, the addition amount of the modified nano-SiO2 is 0.5%, and other process conditions are the same as those in Example 1.

[0072] Comparative Example 9:

[0073] In Step 2, the addition amount of the modified nano-SiO2 is 4%, and other process conditions are the same as those in Example 1.

[0074] The following gives the relevant parameters of the monofilaments in each example and comparative example:

[0075]

[0076] The above data show that: 1. Compared with Example 1, Comparative Example 1 shows that: the nanoparticle solution is too dilute, the crosslinking degree is too large, and the elasticity becomes worse instead;

[0077] 2. Compared with Example 1, Comparative Example 2 shows that when the nanoparticle solution is too concentrated, both the strength and elasticity are poor.

[0078] 3. Compared with Example 1, Comparative Example 3 shows that when other coupling agents are used, the effect becomes worse, and both the strength and elasticity are poor.

[0079] 4. Compared with Example 1, Comparative Example 4 shows that when KH550 is selected as the coupling agent and the amount is too small, both the strength and elasticity are poor.

[0080] 5. Compared with Example 1, Comparative Example 5 shows that when KH550 is selected as the coupling agent and the amount is too large, the degree of crosslinking is high and the elasticity is poor.

[0081] 6. Compared with Example 1, Comparative Example 6 shows that the reaction is incomplete, the grafting rate is not high, there is agglomeration, and both the strength and elasticity are poor.

[0082] 7. Compared with Example 1, Comparative Example 7 shows that when the reaction time is too long and the reaction has been completed, there is no obvious change in the indicators, which is the same as Example 1.

[0083] 8. The results of Comparative Examples 8 and 9 show that when blending with copolyamide, if the amount of modified nanoparticles added is too small, there is no significant change in the improvement of mechanical properties. If the amount is too large, it cannot play the role of enhancing and toughening in the polymer matrix. Instead, it is easy to agglomerate into stress concentration points, resulting in a decrease in the properties of the monofilament itself.

[0084] The above description is only the preferred embodiments of the present application and the explanation of the applied technical principles. Those skilled in the art should understand that the scope of the invention involved in the present application is not limited to the technical solutions formed by the specific combination of the above technical features. It should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the technical solutions formed by mutually replacing the above features with the (but not limited to) technical features with similar functions disclosed in the present application.

Claims

1. A preparation method of a high resilience and anti-creep copolymerized nylon monofilament, characterized in that, it includes the steps: S10: Provide inorganic nanoparticles, and perform surface modification on the inorganic nanoparticles through a silane coupling agent to form modified nanoparticles, where the inorganic nanoparticles are inorganic nano-SiO 2 ; S20: After uniformly mixing the modified nanoparticles and the copolymerized polyamide, add them into a twin-screw extruder for melt blending and extrusion. The mass portion of the modified nanoparticles is 1-2, and the mass portion of the copolymerized polyamide is 98-99; S30: The melt-extruded filament is cooled by a coolant. The temperature of the coolant is less than or equal to 0 °C, and then it is drawn and wound to form a primary filament; S40: The primary filament is subjected to two-stage stretching. The first stretching is steam stretching with a stretching ratio of 3-4 times, and the second stretching is hot air stretching with a stretching ratio of 1.1-1.5 times. Then it is subjected to a setting treatment to form a high resilience and anti-creep copolymerized nylon monofilament; The surface modification of the inorganic nanoparticles specifically includes: S11: Fully mix the inorganic nanoparticles with an ethanol solution with a mass fraction of 75%. The mass ratio of the inorganic nanoparticles to the ethanol solution is 5-10:100; S12: Add the silane coupling agent to the mixed solution, and adjust the pH value of the mixed solution to 7-9 with sodium hydroxide. The addition amount of the silane coupling agent is 1-3% of the mass of the inorganic nanoparticles; S13: Heat the mixed solution to 75-85 °C, keep warm and stir for 6-8 hours; S14: Centrifuge the mixed solution after heat preservation to obtain modified nanoparticles.

2. The preparation method of a high resilience and anti-creep copolymerized nylon monofilament according to claim 1, characterized in that, S10 further includes drying and grinding the modified nanoparticles. The particle size after grinding is 10-20 μm.

3. The preparation method of a high resilience and anti-creep copolymerized nylon monofilament according to claim 1, characterized in that, the inorganic nanoparticles are spherical particles, rod-shaped or layered.

4. The preparation method of a high resilience and anti-creep copolymerized nylon monofilament according to claim 1, characterized in that, the silane coupling agent is one of KH550, KH560, KH570.

5. A copolymerized nylon monofilament prepared by the preparation method of a high resilience and anti-creep copolymerized nylon monofilament according to any one of claims 1-4.

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