High-strength ultra-fine denier nylon 66 filament and method of making same

Abstract

The application provides high-strength superfine denier nylon 66 filaments and a preparation method thereof, and belongs to the technical field of nylon. Nylon 66 spinning grade chips are solid-phase tackified and humidified, a nano modifier is added, melt extrusion is carried out, pressure spinning is carried out after multi-stage filtration, cooling, oiling, drafting and setting, and winding, so that the high-strength superfine denier nylon 66 filaments are prepared. The high-strength superfine denier nylon 66 filaments prepared by the application have high mechanical strength, low denier, small heat shrinkage, uniform and stable yarns, low production cost, good comprehensive performance and wide application prospect.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of nylon, in particular to a high-strength ultra-fine denier nylon 66 filament and a preparation method thereof. BACKGROUND

[0002] Nylon 66, also known as polyhexamethylene adipamide or PA66, is an engineering plastic with excellent performance, high strength, friction resistance, high temperature resistance, corrosion resistance and other characteristics. It has a wide range of applications in the fields of engineering plastics and synthetic fibers, especially in the fields of automobiles, electronics and electrical appliances, rail transportation and other fields. The monomers of nylon 66, adipic acid and hexamethylene diamine, are mainly derived from petroleum and are prepared by polymerization.

[0003] The nylon 66 industry began industrialization in 1939 and was widely used in the fields of chemical fibers and engineering plastics. In the past 10 years, the world's nylon consumption has increased by about 7.5% per year. As an engineering plastic, nylon is widely used in military textiles, industry, clothing, decoration, engineering plastics and other fields.

[0004] High-strength ultra-fine denier nylon 66 fiber has the advantages of high strength, good rigidity, impact resistance, oil and chemical resistance, wear resistance and self-lubrication, especially better hardness, rigidity, heat resistance and creep performance. However, its preparation method is complex, the preparation process is unstable, and the performance of the prepared product is not good.

[0005] Chinese patent document CN101871134A discloses a fine denier nylon 66 fully drawn fiber spinning production process, which adopts a slicing and primary drawing method (a pair of hot rollers) spinning process without heat relaxation and heat setting. The strength of the nylon 66 fiber produced by the patent is 5.2 cN / dtex at 11 dtex / 7f. The nylon 66 fiber produced by the patent has low strength and cannot meet the needs of some high-strength use fields. In addition, the production process disclosed in the patent only uses primary drawing without relaxation and heat setting, which may result in unstable fiber properties, especially after moisture absorption, the strength decreases greatly, affecting the performance of subsequent products. SUMMARY

[0006] The purpose of the present application is to provide a high-strength ultra-fine denier nylon 66 filament and a preparation method thereof, which has high mechanical strength, low denier, small heat shrinkage, uniform and stable yarn, low production cost, good comprehensive performance and broad application prospects.

[0007] The technical solution of the present application is as follows:

[0008] The application provides a preparation method of high-strength ultra-fine denier nylon 66 filaments.

[0009] As a further improvement of the application, the following steps are included:

[0010] S1. Solid phase tackifying and moisture conditioning: the nylon 66 spinning grade chips are subjected to solid phase tackifying and moisture conditioning treatment to obtain nylon 66 medium-high tack chips;

[0011] S2. Melt extrusion: the nylon 66 medium-high tack chips are sent to a screw extruder, and a nano modifier is added for melt extrusion;

[0012] S3. Filtration spinning: the melt is subjected to multi-stage filtration, then is pumped to a spinning box by a pressure boosting pump, is metered by a metering pump, and is spun through a spinning assembly;

[0013] S4. Cooling: the filaments are cooled by side blowing to form a filament bundle;

[0014] S5. Oiling: the cooled filament bundle is subjected to oiling to eliminate static electricity;

[0015] S6. Stretching and setting: the oiled filament bundle is subjected to stretching and setting treatment;

[0016] S7. Winding: the set filament bundle is wound into a filament bobbin to obtain high-strength ultra-fine denier nylon 66 filaments.

[0017] As a further improvement of the application, the relative viscosity of the nylon 66 spinning grade chips in step S1 is 2.2-2.3, the water content of the nylon 66 medium-high tack chips is 650-750 ppm, the relative viscosity is 3.3-3.5, and the solid phase tackifying is carried out on the chips under the condition of 140-170 DEG C and reverse flow circulation of nitrogen; the addition amount of the nano modifier in step S2 is 2-3 wt%, and the temperature of the melt extrusion is 280-300 DEG C.

[0018] As a further improvement of the application, the preparation method of the nano modifier is as follows:

[0019] T1. Preparation of carbon-deposited nano silicon dioxide: nano mesoporous silicon dioxide is added to water, iron chloride is added, stirring and adsorption are carried out, centrifugation, washing and drying are carried out, under the protection of inert gas, n-hexane is introduced, and heating reaction is carried out to obtain carbon-deposited nano silicon dioxide;

[0020] T2. Preparation of modified nano-silica: carbon deposition nano-silica is added to water, dopamine hydrochloride and catalyst are added, heating and stirring reaction, centrifugation, washing, drying, to obtain modified nano-silica;

[0021] T3. Preparation of composite mixed solution: graphene oxide and sodium benzoate are added to water, hydrothermal reaction, to obtain composite mixed solution;

[0022] T4. Coating: modified nano-silica is added to the composite mixed solution, stirring and mixing reaction, centrifugation, washing, drying, to obtain nano-modifier.

[0023] As a further improvement of the present application, the particle size of the nano-mesoporous silica in step T1 is 150-250 nm, the mass ratio of the nano-mesoporous silica to ferric chloride is 10:1-2, the ventilation amount of the n-hexane is 0.2-0.4 mL / min, the temperature of the heating reaction is 600-700℃, and the time is 25-35 min.

[0024] As a further improvement of the present application, the mass ratio of the carbon deposition nano-silica, dopamine hydrochloride and catalyst in step T2 is 12-15:3-5:0.5-1, the catalyst is Tris-HCl solution with pH=8.5-9.5, the temperature of the heating and stirring reaction is 40-50℃, and the time is 2-3 h.

[0025] As a further improvement of the present application, the mass ratio of the graphene oxide and sodium benzoate in step T3 is 10:3-5, the temperature of the hydrothermal reaction is 65-75℃, and the time is 20-24 h; the mass ratio of the modified nano-silica to the composite mixed solution in step T4 is 9-11:30-50, the temperature of the stirring and mixing reaction is 35-45℃, and the time is 1-2 h.

[0026] As a further improvement of the present application, the filament fineness of the spinning nozzle in step S3 is 0.02-0.05 mm, the multi-stage filtration is carried out by suction filtration system and multi-layer filtration device in turn, the multi-layer filtration device is tightly combined by one layer of sand and one layer of mesh in turn, and the last layer is tightly combined with the lower spinning plate; the amount of oil in step S5 is controlled to be 0.5-1.5%; the drafting and setting in step S6 is realized by 1 section of preheating, 2 sections of stretching and 2 sections of setting between six pairs of hot rollers: the temperature of the first pair of hot rollers is 30-40℃, the temperature of the second pair of hot rollers is 45-55℃, the first pair of hot rollers and the second pair of hot rollers play a preheating role on the yarn, and the stretching ratio is 1-1.01 times; the winding speed in step S7 is 3000-4000 m / min.

[0027] The application further protects the high-strength ultra-fine denier nylon 66 filament prepared by the above preparation method.

[0028] As a further improvement of the application, the breaking strength is 12-15 g / D, and the denier is 15-25 D.

[0029] The application has the following beneficial effects:

[0030] The melt flowing in the melt storage cavity is filtered by the air extractor, and the impurities filtered out are guided out of the melt storage cavity through the filter pipe in the melt storage cavity, so as to realize the purpose of filtering out the fine particles, oil mist and other impurities on the surface of the melt and in the cavity; the filtered melt flows into the multiple layers of the filter device through the flow-through hole at the lower end of the storage cavity, and the multiple layers of the filter device are tightly combined and uniformly and staggered distributed, and are tightly combined with the spinneret below, so as to ensure the thickness and flatness of the metal sand and avoid migration, so that the yarns sprayed by high pressure are more uniform and stable.

[0031] The original nylon chip is transported into the drying tower for solid-phase drying and viscosity increase, so that the chip reaches the high-viscosity chip required for spinning, then the dried chip is treated for moisture adjustment to stabilize the water content to 650-750 ppm, in the suitable water content range, the polymerization reaction of the polymer is regulated, the amide group of the nylon forms a hydrogen bond with the water molecules, which can change the mechanical properties of the formed nylon yarn, increase the elongation at break and improve the impact strength, and also expand the material, thereby reducing the denier, so that the ultra-fine denier nylon yarn is obtained. The treated chip is melted and extruded by a screw extruder, and then is transported to the spinning box under high pressure by using a booster pump for secondary pressurization during the melt conveying process, is spun through a metering pump after metering, and the yarn is cooled to form a yarn bundle through low-temperature side blowing, the cooled yarn bundle is oiled to eliminate static electricity, then is drawn and set, and finally is wound into a bobbin on a winding machine.

[0032] The crystallization rate of the nylon material is low, the crystallization morphology and size are difficult to control, and the size stability of the product is low. The addition of the nucleating agent can improve the crystallization rate of the nylon material and also improve the mechanical strength.

[0033] The application adds a nano modifier in the process of melt extrusion, the nano modifier takes inorganic nano mesoporous silica as a core, is a better inorganic nucleating agent of nylon material, has lower cost and has a good reinforcing effect on the mechanical properties of the nylon material, but has poor compatibility with the nylon material, is difficult to uniformly disperse in the nylon material matrix and has low nucleation efficiency. The carbon material is deposited on the surface through chemical vapor deposition, the mechanical modification effect on the nylon material is greatly improved, and after being modified by polydopamine, the dispersion capacity in the nylon material is improved, and the nano modifier can be well compounded and coated with graphene oxide and sodium benzoate, so that a stable nano modifier is obtained.

[0034] The graphene oxide has good compatibility with the nylon material, but direct addition of the graphene oxide can easily cause agglomeration and affect the mechanical improvement of the nylon material. The mixing and reaction of the graphene oxide and sodium benzoate realizes uniform dispersion of the nano filler, effective contact promotes the formation of a heat conduction network, so that the thermal conductivity is improved, the nano modifier is coated on the surface of the modified nano silica, the dispersion and compatibility of the nano modifier in the nylon material are promoted, and the nano modifier is not easy to agglomerate, which helps to improve the mechanical properties, heat dissipation performance and thermal shrinkage rate of the material.

[0035] The high-strength ultra-fine denier nylon 66 filament prepared by the application has high mechanical strength, low denier, small thermal shrinkage rate, uniform and stable yarn, low production cost, good comprehensive performance and wide application prospect. DETAILED DESCRIPTION

[0036] The technical solutions in the embodiments of the application will be clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the application.

[0037] The nano mesoporous silica has an average particle size of 200 nm; the graphene oxide has a purity of >99%, a thickness of <5 nm and an average flake diameter of 20 μm, and is purchased from Jiangsu Xianfeng Nanometer Material Technology Co., Ltd.

[0038] Preparation of the nano modifier

[0039] The method comprises the following steps:

[0040] T1. Preparation of carbon-deposited nano silica: 10 g of nano mesoporous silica is added to 200 mL of water, 1 g of ferric chloride is added, stirring and adsorption is performed for 20 min, centrifugation, washing, drying, nitrogen protection, hexane is introduced at a flow rate of 0.2 mL / min, heating to 600℃, and reaction is performed for 25 min to obtain carbon-deposited nano silica;

[0041] T2. Preparation of modified nanosilica: 12 g of carbon-deposited nanosilica was added to 200 mL of water, 3 g of dopamine hydrochloride and 0.5 g of catalyst were added, heated to 40°C, stirred for 2 h, centrifuged, washed, dried, and modified nanosilica was prepared;

[0042] The catalyst is Tris-HCl solution with pH = 8.5;

[0043] T3. Preparation of composite mixture: 1 g of graphene oxide and 0.3 g of sodium benzoate were added to 100 mL of water, and hydrothermal reaction was carried out at 65°C for 20 h to prepare the composite mixture;

[0044] T4. Coating: 9 g of modified nanosilica was added to 30 g of composite mixture, and mixed reaction was carried out at 35°C for 1 h, centrifuged, washed, dried, and nanomodifier was prepared.

[0045] Preparation of nanomodifier of Preparation Example 2

[0046] The preparation includes the following steps:

[0047] T1. Preparation of carbon-deposited nanosilica: 10 g of nanometer mesoporous silica was added to 200 mL of water, 2 g of ferric chloride was added, stirred for 20 min, centrifuged, washed, dried, and under the protection of nitrogen, the flow rate of the introduced n-hexane was 0.4 mL / min, heated to 700°C, and reacted for 35 min to prepare carbon-deposited nanosilica;

[0048] T2. Preparation of modified nanosilica: 15 g of carbon-deposited nanosilica was added to 200 mL of water, 5 g of dopamine hydrochloride and 1 g of catalyst were added, heated to 50°C, stirred for 3 h, centrifuged, washed, dried, and modified nanosilica was prepared;

[0049] The catalyst is Tris-HCl solution with pH = 9.5;

[0050] T3. Preparation of composite mixture: 1 g of graphene oxide and 0.5 g of sodium benzoate were added to 100 mL of water, and hydrothermal reaction was carried out at 75°C for 24 h to prepare the composite mixture;

[0051] T4. Coating: 11 g of modified nanosilica was added to 50 g of composite mixture, and mixed reaction was carried out at 45°C for 2 h, centrifuged, washed, dried, and nanomodifier was prepared.

[0052] Preparation of nanomodifier of Preparation Example 3

[0053] The preparation includes the following steps:

[0054] T1. Preparation of carbon-deposited nanosilica: 10 g of nanosilica was added to 200 mL of water, 1.5 g of ferric chloride was added, and stirring adsorption was performed for 20 min. Centrifugation, washing, and drying were performed, and under the protection of nitrogen, hexane was introduced at a flow rate of 0.3 mL / min. Heating was performed to 650 DEG C, and reaction was performed for 30 min. Carbon-deposited nanosilica was prepared.

[0055] T2. Preparation of modified nanosilica: 13 g of carbon-deposited nanosilica was added to 200 mL of water, 4 g of dopamine hydrochloride and 0.7 g of a catalyst were added, heating was performed to 45 DEG C, and stirring reaction was performed for 2.5 h. Centrifugation, washing, and drying were performed. Modified nanosilica was prepared.

[0056] The catalyst was a Tris-HCl solution with pH = 9;

[0057] T3. Preparation of a composite mixture: 1 g of graphene oxide and 0.4 g of sodium benzoate were added to 100 mL of water, and hydrothermal reaction was performed at 70 DEG C for 22 h. A composite mixture was prepared.

[0058] T4. Coating: 10 g of modified nanosilica was added to 40 g of the composite mixture, stirring and mixing reaction was performed at 40 DEG C for 1.5 h, centrifugation, washing, and drying were performed. A nanomodifier was prepared.

[0059] Comparative Preparation Example 1

[0060] Compared with Preparation Example 3, the difference is that step T1 is not performed.

[0061] Details are as follows:

[0062] T1. Preparation of modified nanosilica: 13 g of nanosilica was added to 200 mL of water, 4 g of dopamine hydrochloride and 0.7 g of a catalyst were added, heating was performed to 45 DEG C, and stirring reaction was performed for 2.5 h. Centrifugation, washing, and drying were performed. Modified nanosilica was prepared.

[0063] The catalyst was a Tris-HCl solution with pH = 9;

[0064] T2. Preparation of a composite mixture: 1 g of graphene oxide and 0.4 g of sodium benzoate were added to 100 mL of water, and hydrothermal reaction was performed at 70 DEG C for 22 h. A composite mixture was prepared.

[0065] T3. Coating: 10 g of modified nanosilica was added to 40 g of the composite mixture, stirring and mixing reaction was performed at 40 DEG C for 1.5 h, centrifugation, washing, and drying were performed. A nanomodifier was prepared.

[0066] Comparative Preparation Example 2

[0067] Compared with Preparation Example 3, the difference is that step T2 is not performed.

[0068] Specifically as follows:

[0069] T1. Preparation of carbon-deposited nanosilica: 10 g of nanometer mesoporous silica was added to 200 mL of water, 1.5 g of ferric chloride was added, and stirring adsorption was performed for 20 min, centrifugation, washing, drying, and under the protection of nitrogen, the introduction of n-hexane was performed at a flow rate of 0.3 mL / min, heating to 650℃, and reaction for 30 min to prepare carbon-deposited nanosilica;

[0070] T2. Preparation of a composite mixed solution: 1 g of graphene oxide and 0.4 g of sodium benzoate were added to 100 mL of water, and hydrothermal reaction was performed at 70℃ for 22 h to prepare a composite mixed solution;

[0071] T3. Coating: 10 g of carbon-deposited nanosilica was added to 40 g of the composite mixed solution, and stirring mixing reaction was performed at 40℃ for 1.5 h, centrifugation, washing, and drying to prepare a nanomodifier.

[0072] Comparative Preparation Example 3

[0073] Compared with Preparation Example 3, the difference lies in that no sodium benzoate was added in step T3.

[0074] Specifically as follows:

[0075] T3. Preparation of a graphene oxide solution: 1.4 g of graphene oxide was added to 100 mL of water to prepare a graphene oxide solution.

[0076] Comparative Preparation Example 4

[0077] Compared with Preparation Example 3, the difference lies in that steps T3 and T4 were not performed.

[0078] Specifically as follows:

[0079] T1. Preparation of carbon-deposited nanosilica: 10 g of nanometer mesoporous silica was added to 200 mL of water, 1.5 g of ferric chloride was added, and stirring adsorption was performed for 20 min, centrifugation, washing, drying, and under the protection of nitrogen, the introduction of n-hexane was performed at a flow rate of 0.3 mL / min, heating to 650℃, and reaction for 30 min to prepare carbon-deposited nanosilica;

[0080] T2. Preparation of modified nanosilica: 13 g of carbon-deposited nanosilica was added to 200 mL of water, 4 g of dopamine hydrochloride and 0.7 g of a catalyst were added, heating to 45℃, stirring reaction for 2.5 h, centrifugation, washing, and drying to prepare modified nanosilica, which is a nanomodifier;

[0081] The catalyst is a Tris-HCl solution with pH = 9.

[0082] Example 1

[0083] The embodiment provides a preparation method of high-strength ultra-fine denier nylon 66 filament, which comprises the following steps:

[0084] S1. Solid phase tackifying and moisture adjusting: nylon 66 spinning grade chips with a relative viscosity of 2.2 are subjected to solid phase tackifying and moisture adjusting treatment to obtain nylon 66 medium-high tackiness chips with a water content of 650 ppm and a relative viscosity of 3.3; the solid phase tackifying is carried out on the chips by adopting nitrogen for countercurrent circulation at 140 DEG C;

[0085] S2. Melt extrusion: the nylon 66 medium-high tackiness chips are sent to a screw extruder, and the nano modifier prepared in preparation example 1 is added in an amount of 2 wt%, and melt extrusion is carried out at 280 DEG C;

[0086] S3. Filtration spinning: the melt is subjected to multi-stage filtration, and then is conveyed to a spinning box by a booster pump, and is spun through a spinning assembly after metering by a metering pump, and the spun filament has a fineness of 0.02 mm;

[0087] The multi-stage filtration is carried out by sequentially performing suction filtration by a suction filtration system and filtration by a multi-layer filtration device, the multi-layer filtration device is sequentially and closely combined by one layer of sand and one layer of mesh, and the last layer is closely combined with the lower spinneret;

[0088] S4. Cooling: the yarn is cooled by side blowing to form a yarn bundle;

[0089] S5. Oiling: the cooled yarn bundle is subjected to oiling to eliminate static electricity, and the oil addition amount is controlled to be 0.5%;

[0090] S6. Drafting and setting: the oiled yarn bundle is subjected to drafting and setting treatment; the drafting and setting are realized by 1 stage of preheating, 2 stages of stretching and 2 stages of setting between six pairs of hot rollers, wherein the temperature of the first pair of hot rollers is 30 DEG C, the temperature of the second pair of hot rollers is 45 DEG C, the first pair of hot rollers and the second pair of hot rollers preheat the yarn, and the stretching ratio is 1 times;

[0091] S7. Winding: the set yarn bundle is wound into a yarn can, and the winding speed is 3000 m / min, and the high-strength ultra-fine denier nylon 66 filament is prepared.

[0092] Embodiment 2

[0093] The embodiment provides a preparation method of high-strength ultra-fine denier nylon 66 filament, which comprises the following steps:

[0094] S1. Solid phase tackifying and moisture adjusting: nylon 66 spinning grade chips with a relative viscosity of 2.3 are subjected to solid phase tackifying and moisture adjusting treatment to obtain nylon 66 medium-high tackiness chips with a water content of 750 ppm and a relative viscosity of 3.5; the solid phase tackifying is carried out on the chips by adopting nitrogen for countercurrent circulation at 170 DEG C;

[0095] S2. melt extrusion: the nylon 66 medium-high viscosity chip is sent to a screw extruder, the nano modifier prepared in Preparation Example 2 is added, the addition amount is 3wt%, and melt extrusion is carried out at 300℃;

[0096] S3. filtration spinning: the melt is filtered through multiple stages, then is delivered to a spinning box through a booster pump, is metered through a metering pump, and is jetted through a spinning assembly, the jetted filament fineness is 0.05mm;

[0097] The multiple-stage filtration is carried out through suction filtration of a suction filtration system and filtration of a multi-layer filtration device in sequence, the multi-layer filtration device is sequentially and tightly combined by one layer of sand and one layer of mesh, and the last layer is tightly combined with the lower spinneret;

[0098] S4. cooling: the yarn is cooled through side blowing to form a yarn bundle;

[0099] S5. oiling: the cooled yarn bundle is subjected to oiling to eliminate static electricity, and the oil addition amount is controlled to be 1.5%;

[0100] S6. drafting and setting: the oiled yarn bundle is subjected to drafting and setting treatment; through 1st preheating, 2nd stretching, and 2nd setting between six pairs of hot rollers, the first pair of hot rollers has a temperature of 40℃, the second pair of hot rollers has a temperature of 55℃, the first pair of hot rollers and the second pair of hot rollers preheat the yarn, and the stretching ratio is 1.01 times;

[0101] S7. winding: the set yarn bundle is wound into a yarn can, the winding speed is 4000m / min, and a high-strength ultra-fine denier nylon 66 filament is prepared.

[0102] Example 3

[0103] The embodiment provides a preparation method of a high-strength ultra-fine denier nylon 66 filament, comprising the following steps:

[0104] S1. solid-phase viscosity increase and moisture adjustment: nylon 66 spinning-grade chips with a relative viscosity of 2.25 are subjected to solid-phase viscosity increase and moisture adjustment treatment, to obtain nylon 66 medium-high viscosity chips with a water content of 700ppm and a relative viscosity of 3.4; the solid-phase viscosity increase is carried out on the chips under the condition of 155℃ and through countercurrent circulation of nitrogen;

[0105] S2. melt extrusion: the nylon 66 medium-high viscosity chip is sent to a screw extruder, the nano modifier prepared in Preparation Example 3 is added, the addition amount is 2.5wt%, and melt extrusion is carried out at 290℃;

[0106] S3. filtration spinning: the melt is filtered through multiple stages, then is delivered to a spinning box through a booster pump, is metered through a metering pump, and is jetted through a spinning assembly, the jetted filament fineness is 0.03mm;

[0107] The multi-stage filtration is carried out in turn by suction filtration system suction filtration and multi-layer filter device filtration, the multi-layer filter device is sequentially and closely combined by one layer of sand and one layer of net, and the last layer is closely combined with the lower spinneret;

[0108] S4. Cooling: the filaments are cooled by side blowing to form a tow;

[0109] S5. Oiling: the cooled tow is passed through an oiling device to eliminate static electricity, and the attached amount of oil is controlled to be 1%;

[0110] S6. Drafting and setting: the oiled tow is subjected to drafting and setting treatment; 1 section of preheating, 2 sections of stretching and 2 sections of setting are realized between six pairs of hot rollers: the temperature of the first pair of hot rollers is 35℃, the temperature of the second pair of hot rollers is 50℃, the first pair of hot rollers and the second pair of hot rollers preheat the filaments, and the stretching ratio is 1.005 times;

[0111] S7. Winding: the set tow is wound into a bobbin at a speed of 3500 m / min, and high-strength ultra-fine denier nylon 66 filaments are prepared.

[0112] Comparative Example 1

[0113] Compared with Example 3, the difference lies in that the nano modifier is prepared from Comparative Preparation Example 1.

[0114] Comparative Example 2

[0115] Compared with Example 3, the difference lies in that the nano modifier is prepared from Comparative Preparation Example 2.

[0116] Comparative Example 3

[0117] Compared with Example 3, the difference lies in that the nano modifier is prepared from Comparative Preparation Example 3.

[0118] Comparative Example 4

[0119] Compared with Example 3, the difference lies in that the nano modifier is prepared from Comparative Preparation Example 4.

[0120] Comparative Example 5

[0121] Compared with Example 3, the difference lies in that no nano modifier is added.

[0122] Comparative Example 6

[0123] Compared with Example 3, the difference lies in that no multi-layer filter device filtration is performed.

[0124] Comparative Example 7

[0125] Compared with Example 3, the difference lies in that the moisture content after humidification is 300 ppm.

[0126] Test Example 1

[0127] The high-strength ultra-fine denier nylon 66 filaments prepared from the examples 1-3 and the comparative examples 1-7 of the present application were tested for performance, and the results are shown in Table 1.

[0128] Table 1

[0129]

[0130] From the above table, it can be seen that the high-strength ultra-fine denier nylon 66 filaments prepared from the examples 1-3 of the present application have good comprehensive performance.

[0131] The above description is merely preferred embodiments of the present application, but not to limit the present application, and any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A process for the production of high-strength ultra-fine denier nylon 66 filaments, characterized in that, High-strength ultra-fine denier nylon 66 filaments are prepared by solid-phase tackifying and moisture conditioning of nylon 66 spinning grade chips, adding nano-modifier, melt extrusion, multi-stage filtration, pressure spinning, cooling, oiling, drawing and setting, winding, and the nano-modifier is prepared by the following method: T1. Preparation of carbon-deposited nano-silica: nano-mesoporous silica is added to water, iron chloride is added, stirred and adsorbed, centrifuged, washed, dried, and then n-hexane is introduced under inert gas protection, and heated to react to obtain carbon-deposited nano-silica; the mass ratio of the nano-mesoporous silica and the iron chloride is 10:1-2; T2. Preparation of modified nano-silica: carbon-deposited nano-silica is added to water, dopamine hydrochloride and a catalyst are added, heated and stirred to react, centrifuged, washed, and dried to obtain modified nano-silica; the mass ratio of the carbon-deposited nano-silica, the dopamine hydrochloride and the catalyst is 12-15:3-5:0.5-1; T3. Preparation of a composite mixture: graphene oxide and sodium benzoate are added to water, and a composite mixture is prepared by hydrothermal reaction; the mass ratio of the graphene oxide and the sodium benzoate is 10:3-5; T4. Coating: modified nano-silica is added to the composite mixture, stirred and mixed to react, centrifuged, washed, and dried to obtain a nano-modifier; the mass ratio of the modified nano-silica and the composite mixture is 9-11:30-50.

2. The production method according to claim 1, characterized by, The method comprises the following steps: S1. Solid-phase tackifying and moisture conditioning: nylon 66 spinning grade chips are subjected to solid-phase tackifying and moisture conditioning to obtain nylon 66 medium-high tack chips; S2. Melt extrusion: the nylon 66 medium-high tack chips are fed into a screw extruder, and a nano-modifier is added for melt extrusion; S3. Filtration and spinning: the melt is filtered through multiple stages, then is pumped by a pressure booster to a spinning box, and is spun through a spinning assembly after being metered by a metering pump; S4. Cooling: the yarn is cooled by side blowing to form a yarn bundle; S5. Oiling: the cooled yarn bundle is oiled to eliminate static electricity; S6. Drawing and setting: the oiled yarn bundle is subjected to drawing and setting; S7. Winding: the set yarn bundle is wound into a yarn can to obtain high-strength ultra-fine denier nylon 66 filaments.

3. The preparation method according to claim 2, characterized in that, In step S1, the relative viscosity of the nylon 66 spinning grade chips is 2.2-2.3, the water content of the nylon 66 medium-high tack chips is 650-750 ppm, and the relative viscosity is 3.3-3.5; the solid-phase tackifying is carried out by reverse flow circulation of the chips at 140-170 DEG C under nitrogen; in step S2, the addition amount of the nano-modifier is 2-3 wt%, and the melt extrusion temperature is 280-300 DEG C.

4. The method of claim 1, wherein, In step T1, the particle size of the nano-mesoporous silica is 150-250 nm, the n-hexane flow rate is 0.2-0.4 mL / min, the heating reaction temperature is 600-700 DEG C, and the reaction time is 25-35 min.

5. The preparation method according to claim 1, characterized in that, The catalyst in step T2 is Tris-HCl solution with pH=8.5-9.5, the temperature of the heated stirring reaction is 40-50℃, and the time is 2-3h.

6. The method of claim 1, wherein, The temperature of the hydrothermal reaction in step T3 is 65-75℃, and the time is 20-24h; the temperature of the stirring mixing reaction in step T4 is 35-45℃, and the time is 1-2h.

7. The preparation method according to claim 2, characterized in that, In step S3, the filament fineness of the jetting is 0.02-0.05mm, the multi-stage filtration is carried out by filtration system filtration and multi-layer filtration device filtration in turn, the multi-layer filtration device is composed of a layer of sand and a layer of net in order, and the last layer is tightly combined with the lower jetting plate; in step S5, the oil addition is controlled to be 0.5-1.5%; in step S6, the drafting and setting are realized by 1 section of preheating, 2 sections of stretching, and 2 sections of setting between six pairs of hot rollers: the temperature of the first pair of hot rollers is 30-40℃, the temperature of the second pair of hot rollers is 45-55℃, the first pair of hot rollers and the second pair of hot rollers have a preheating effect on the yarn, and the stretching ratio is 1-1.01 times; in step S7, the winding speed is 3000-4000m / min.

8. A high-strength ultra-fine denier nylon 66 filament prepared by the preparation method of any one of claims 1-7.

9. The high-strength microdenier nylon 66 filament of claim 8, wherein, The breaking strength is 12-15g / D, and the denier is 15-25D.

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