High-enthalpy-value non-molten-drop nylon 66 filament and preparation method thereof

Abstract

The invention relates to the technical field of high polymer materials, and discloses a high-enthalpy-value non-molten-drop nylon 66 filament and a preparation method thereof. The preparation method of the high-enthalpy-value non-molten-drop nylon 66 filament comprises the following steps: reacting epoxy modified boron nitride with 1-amino-3-butene-2-alcohol to obtain functionalized boron nitride; phase change microcapsules are prepared by taking octadecane as a core material and functionalized boron nitride as a wall material additive; grafting the nylon 66 to obtain grafted modified nylon 66; combining the phase change microcapsules with the grafted nylon 66 to obtain phase change modified nylon 66; the preparation method comprises the following steps: mixing phase change modified nylon 66 and a functional additive, carrying out melt extrusion, carrying out melt spinning, and carrying out water cooling, oiling, hot drafting and air cooling winding to obtain the high-enthalpy-value non-molten-drop nylon 66 filament. The high-enthalpy-value non-molten-drop nylon 66 filament disclosed by the invention is high in enthalpy value and has excellent flame retardance, molten-drop resistance and water resistance.

Description

Technical Field

[0001] The invention relates to the technical field of polymer materials, in particular to a high enthalpy non-melting nylon 66 filament and a preparation method thereof. Background Art

[0002] Temperature changes are closely related to people's daily lives. The greenhouse effect, extreme abnormal climate, and the stuffy feeling of special protective clothing can seriously affect the physical and mental health of the human body. Thermostatic fabrics can spontaneously regulate temperature to provide a comfortable wearing experience for the human body. Nylon has excellent processing and mechanical properties and is one of the commonly used materials for thermostatic fabrics. Nylon 66 is a common nylon material with a limiting oxygen index value of 24 and a UL-94 flame retardant grade of V-2. The disadvantage of poor flame retardancy limits its application range. Therefore, it is of great significance to solve the flame retardant problem of nylon 66. For example, Chinese patent CN107057346B discloses a flame-retardant nylon composition, which includes the following components in percentage by mass: nylon 6660%-93%; inorganic-coated organic silsesquioxane flame retardant 1%-15%; nitrogen-based flame retardant and / or phosphorus-based flame retardant 5%-25%; stabilizer 0.1%-1%. The inorganic-coated organic silsesquioxane flame retardant is compounded with nitrogen-based flame retardant and / or phosphorus-based flame retardant to achieve a good flame retardant effect, but the anti-dripping performance of the flame-retardant nylon composition needs to be further improved. Summary of the invention

[0003] In order to solve the above technical problems, the present invention provides a method for preparing high enthalpy non-melting nylon 66 filaments, comprising the following steps:

[0004] Step (1), first modifying boron nitride to obtain epoxy-modified boron nitride, and reacting the epoxy-modified boron nitride with 1-amino-3-butene-2-ol to obtain functionalized boron nitride;

[0005] Step (2), using octadecane as the core material, methyl methacrylate as the wall material, pentaerythritol tetraacrylate as the wall material crosslinking agent, and functionalized boron nitride as the wall material additive to prepare phase change microcapsules;

[0006] Step (3), grafting nylon 66 with 2-hydroxyethyl acrylate to obtain grafted modified nylon 66;

[0007] Phase change microcapsules were combined with grafted nylon 66 using isophorone diisocyanate as a crosslinking agent to obtain phase change modified nylon 66.

[0008] Step (4), the phase change modified nylon 66 and the functional additive are mixed and melt-extruded, melt-spinned, and then water-cooled, oiled, hot-drawn and air-cooled and wound to obtain high thermal enthalpy non-melting nylon 66 filaments;

[0009] Wherein, the preparation method of the functional additive comprises the following steps:

[0010] Step S1, modifying citric acid with thionyl chloride to obtain modified citric acid, and reacting the modified citric acid with p-hydroxybenzaldehyde to obtain an intermediate product A;

[0011] Step S2, the intermediate product A reacts with pyrrole to obtain an intermediate product B; the intermediate product B reacts with ethylenediamine to obtain an intermediate product C;

[0012] Step S3: the intermediate product C reacts with 4,4'-(hydroxyphosphoryl)dibenzoic acid to obtain an intermediate product D; the intermediate product D reacts with ethylene glycol and sodium carbonate to obtain a functional additive.

[0013] Preferably, in the step (1), the epoxy-modified boron nitride is prepared by the following method: adding boron nitride powder and γ-glycidyloxypropyltrimethoxysilane to ethanol, adding deionized water after ultrasonic treatment for 20-40 minutes, adjusting the pH of the mixed system to 4.5-5.5 with oxalic acid, heating to 55-65°C and stirring for 100-150 minutes, filtering, washing, and drying, wherein the mass ratio of boron nitride powder, γ-glycidyloxypropyltrimethoxysilane, ethanol, and deionized water is (2-3):(2-3):(80-120):(15-25);

[0014] In the above process, γ-glycidyloxypropyltrimethoxysilane is used to modify boron nitride and introduce epoxy groups on the surface of boron nitride.

[0015] Preferably, in step (1), the preparation method of the functionalized boron nitride is as follows: epoxy-modified boron nitride is added to N,N-dimethylformamide and stirred, and then 1-amino-3-butene-2-ol is added, and the reaction is continued at 70-90° C. with stirring for 20-30 hours. After the reaction is completed, centrifugation, washing, and drying are performed, wherein the mass ratio of epoxy-modified boron nitride, N,N-dimethylformamide, and 1-amino-3-butene-2-ol is (2.5-3.5):(50-100):(0.8-1.5);

[0016] In the above process, the epoxy group in the epoxy-modified boron nitride reacts with the amino group of 1-amino-3-butene-2-ol to introduce a carbon-carbon double bond and a hydroxyl group on the surface of the boron nitride.

[0017] Preferably, in the step (2), the preparation method of the phase change microcapsule is: mixing the oil phase and the water phase, stirring and dispersing at a speed of 2800-3200 r / min at 33-38°C for 10-20 min to form an oil-in-water emulsion; stirring the oil-in-water emulsion in a water bath at 80-90°C at a speed of 500-700 r / min for 5-7 h, filtering, washing, and drying.

[0018] Furthermore, in the step (2), the aqueous phase is obtained by mixing sodium dodecyl sulfate and deionized water in a mass ratio of (4.5-10.5):(100-200); the oil phase is obtained by mixing methyl methacrylate, pentaerythritol tetraacrylate, octadecane, azobisisobutyronitrile, and functionalized boron nitride in a mass ratio of (50-100):(10-20):(50-100):(0.1-5):(10-20), and ultrasonicating for 20-40 minutes;

[0019] In the above process, sodium dodecyl sulfate is used as an emulsifier, methyl methacrylate is used as a main component of the wall material, pentaerythritol tetraacrylate is used as a crosslinker of the wall material, and functionalized boron nitride is used as a wall material additive. Under the initiation of azobisisobutyronitrile, methyl methacrylate, pentaerythritol tetraacrylate, and functionalized boron nitride are polymerized through reactions between double bonds to wrap octadecane to form phase change microcapsules. Octadecane has the characteristics of high thermal enthalpy and high physical and chemical stability. Its phase change temperature is between 20-30°C, which is within the comfortable temperature range for the human body.

[0020] Preferably, in step (3), the preparation method of the graft modified nylon 66 is as follows: 2-hydroxyethyl acrylate, hydrogen peroxide and water are mixed to obtain a treatment liquid, nylon 66 powder is added to the treatment liquid at 63-68°C, soaked for 80-120 minutes, filtered, washed and dried to obtain graft modified nylon 66, wherein the mass ratio of 2-hydroxyethyl acrylate, hydrogen peroxide, water and nylon 66 powder is (5-15):(0.25-0.75):(11.4-34.2):10;

[0021] In the above process, hydrogen peroxide provides a free radical source, and hydroxyl radicals attack the polyamide main chain of nylon 66 to form polymer free radicals. The polymer free radicals interact with the double bonds of 2-hydroxyethyl acrylate to form a copolymer, thereby grafting 2-hydroxyethyl acrylate onto nylon 66 and introducing hydroxyl groups into nylon 66.

[0022] Preferably, in step (4), the preparation method of the phase change modified nylon 66 is as follows: adding isophorone diisocyanate and dibutyltin dilaurate to acetone, heating to 55-60°C, adding grafted modified nylon 66, stirring to react for 3-5h, and then adding phase change microcapsules. After the -NCO reaction is complete, evaporating and removing acetone; wherein the mass ratio of isophorone diisocyanate, dibutyltin dilaurate, acetone, grafted modified nylon 66, and phase change microcapsules is (8.8-13.2):(0.03-0.06):(50-80):(15-25):(5-15);

[0023] In the above process, the two isocyanate groups of isophorone diisocyanate react with the hydroxyl groups on the grafted modified nylon 66 and the wall of the phase change microcapsule respectively. Isophorone diisocyanate plays the role of a cross-linking agent to connect the phase change microcapsule to the grafted modified nylon 66.

[0024] Preferably, in step (4), the mass ratio of the phase change modified nylon 66 to the functional additive is 1:(0.1-0.4); and the melt spinning temperature is 250-260°C.

[0025] Preferably, in step (4), the preparation method of the functional additive is:

[0026] Step S1, adding citric acid to tetrahydrofuran, then adding thionyl chloride, heating to 57-63°C for reaction for 20-30h, after the reaction is completed, evaporating to remove the solvent and excess thionyl chloride to obtain modified citric acid, wherein the mass ratio of citric acid, tetrahydrofuran and thionyl chloride is (1.9-3.8):(30-50):(4.2-8.5);

[0027] Add modified citric acid to ethanol, stir for 10-30 minutes, then add p-hydroxybenzaldehyde, react at room temperature for 20-25 hours, and after the reaction is completed, evaporate and remove the solvent to obtain an intermediate product A; wherein the mass ratio of modified citric acid, ethanol, and p-hydroxybenzaldehyde is (2.5-5):(40-50):(1.2-2.5);

[0028] In the above process, the carboxyl group of citric acid reacts with thionyl chloride to convert the carboxyl group in citric acid into acyl chloride, and the acyl chloride then reacts with the phenolic hydroxyl group of p-hydroxybenzaldehyde to obtain intermediate product A;

[0029] Step S2, adding the intermediate product A to a mixed solution of propionic acid and propionic anhydride, adding dropwise a 9.2wt% pyrrole / propionic acid mixed solution at a rate of 0.8-1.2mL / min at 145-155°C, reacting for 3.5-4.5h in a nitrogen atmosphere, and after the reaction, removing the solvent by rotary evaporation, and obtaining an intermediate product B by petroleum ether column chromatography; wherein the mass ratio of the intermediate product A, propionic acid, propionic anhydride, and pyrrole / propionic acid mixed solution is (4.7-9.4):(100-200):(40-80):(22-44);

[0030] Add ethylenediamine to N,N-dimethylformamide, then add intermediate product B, heat to 80-100°C and react for 20-26 hours. After the reaction is completed, distill and chromatograph by petroleum ether column to obtain intermediate product C; wherein the mass ratio of ethylenediamine, N,N-dimethylformamide and intermediate product B is (2-3.5):(30-50):(5.1-10.2);

[0031] In the above process, the aldehyde group in the intermediate product A reacts with pyrrole to form an intermediate product B containing a porphyrin ring structure; the unreacted acyl chloride in the intermediate product B reacts with the amino group of ethylenediamine to form an intermediate product C;

[0032] Step S3, at room temperature, adding the intermediate product C to methanol, then adding 4,4'-(hydroxyphosphoryl)dibenzoic acid, and dropping a methanol solution of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide at a concentration of 0.07 g / L while stirring, stirring for 20-30 hours, and after the reaction is completed, filtering, washing, and drying to obtain an intermediate product D; wherein the amount ratio of the intermediate product C, methanol, 4,4'-(hydroxyphosphoryl)dibenzoic acid, and the methanol solution of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide is (1.7-3.4) g:(80-150) g:(1.5-3.5) g:(15-30) mL;

[0033] The intermediate product D and ethylene glycol are mixed, heated to 45-55° C., sodium carbonate is added, and the mixture is stirred to react until no gas is released, and then the pressure is adjusted to 40-100 Pa and heated to 55-65° C., the mixture is stirred to react until no gas is released, cooled, filtered, washed, and dried to obtain a functional additive; wherein the mass ratio of the intermediate product D, ethylene glycol, and sodium carbonate is (22.5-45):(200-300):(0.6-1.2);

[0034] In the above process, the amino group in the intermediate product C reacts with the carboxyl group at one end of 4,4'-(hydroxyphosphoryl)dibenzoic acid to form the intermediate product D; the carboxyl group and the phosphoryl group in the intermediate product D react with ethylene glycol and sodium carbonate to form phosphorus-containing ion groups and ethylene glycol esters, thereby obtaining a functional additive containing a porphyrin ring, a benzene ring, an amide group, a hydroxyl group, an ester group, and a phosphorus-containing ion group.

[0035] The high enthalpy non-melting nylon 66 filaments are prepared by the method for preparing the high enthalpy non-melting nylon 66 filaments.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] 1. The present invention uses methyl methacrylate as the main component of the wall material, pentaerythritol tetraacrylate as the wall material crosslinking agent, and functionalized boron nitride as the wall material additive to wrap octadecane to form a phase change microcapsule. Boron nitride has excellent thermal conductivity, thermal stability and mechanical properties. Using it as a wall material additive can not only enhance the mechanical properties of the microcapsule wall material, prevent the microcapsule shell from being damaged in subsequent treatment to cause the leakage of the phase change material octadecane, but also enhance the thermal stability and temperature response sensitivity of the microcapsule wall material, increase the enthalpy value of the microcapsule, and enable the phase change microcapsule to play an excellent heat storage and temperature regulation effect. In addition, , boron nitride is functionalized and added to the wall material in the form of chemical bonds, which can prevent boron nitride from agglomerating and make it more evenly distributed in the wall material to achieve better results; further, nylon 66 is grafted with 2-hydroxyethyl acrylate, and isophorone diisocyanate is used as a cross-linking agent to connect phase change microcapsules to the grafted modified nylon 66 in the form of chemical bonds, so that the phase change microcapsules are evenly distributed in the nylon 66 filaments, and the connection strength between the phase change microcapsules and the grafted modified nylon 66 is increased, thereby improving the water washability of the nylon 66 filaments.

[0038] 2. The present invention blends functional additives with phase change modified nylon 66 to prepare high enthalpy non-melting nylon 66 filaments. The functional additives contain a variety of functional groups (porphyrin ring, benzene ring, amide group, hydroxyl group, ester group, phosphorus-containing ion group) and nitrogen and phosphorus elements. During the combustion process, the nitrogen and phosphorus elements can play a synergistic flame retardant effect; π-π stacking is formed between the porphyrin ring and the benzene ring, hydrogen bonding can be formed between the functional groups in the functional additives, and the phosphorus-containing ion groups form ion aggregation when heated. A physical cross-linking network is formed under the joint action of hydrogen bond cross-linking and ion aggregation, which restricts the movement of nylon 66 polymer chains, effectively improves the melt viscosity and strength of nylon 66, promotes carbonization, and achieves the effect of flame retardancy and anti-melt dripping; further, the functional additives and phase change modified nylon 66 can also be cross-linked through hydrogen bonds, so that the cross-linking density of the functional additive and phase change modified nylon 66 blend system is increased, and the introduction of porphyrin ring and benzene ring rigid groups has a positive effect on the improvement of the mechanical properties of nylon 66 filaments. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a process flow chart of the preparation method of high enthalpy non-melting nylon 66 filament of the present invention;

[0040] Figure 2 It is a schematic diagram of the synthesis of the intermediate product A of the present invention;

[0041] Figure 3 It is a schematic diagram of the synthesis of the intermediate product C of the present invention;

[0042] Figure 4 It is a schematic diagram of the synthesis of the functional additive of the present invention;

[0043] Figure 5 It is a comparison chart of limiting oxygen index test of high enthalpy non-melting nylon 66 filaments of Examples 2-4 of the present invention and Comparative Examples 2-7;

[0044] Figure 6 It is a comparison chart of the melting enthalpy value test of high enthalpy value non-melting nylon 66 filaments after washing 50 times in Examples 2-4 of the present invention and Comparative Examples 2-7. DETAILED DESCRIPTION

[0045] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0046] Example 1

[0047] This embodiment discloses a method for preparing a functional additive, comprising the following steps:

[0048] Step S1, adding 2.7 g of citric acid to 4 g of tetrahydrofuran, and then adding 6.4 g of thionyl chloride, heating to 60° C. to react for 25 h. After the reaction is completed, evaporating to remove the solvent and excess thionyl chloride to obtain modified citric acid;

[0049] 3.8 g of modified citric acid was added to 45 g of ethanol, stirred for 20 min, and then 1.9 g of p-hydroxybenzaldehyde was added, and the reaction was carried out at room temperature for 22 h. After the reaction was completed, the solvent was evaporated to obtain an intermediate product A;

[0050] Step S2, adding 7.1 g of the intermediate product A to a mixture of 150 g of propionic acid and 60 g of propionic anhydride, adding dropwise 33 g of a 9.2 wt% pyrrole / propionic acid mixed solution at a rate of 1 mL / min at 150° C., reacting for 4 h in a nitrogen atmosphere, and after the reaction, removing the solvent by rotary evaporation, and obtaining an intermediate product B by petroleum ether column chromatography;

[0051] 2.8 g of ethylenediamine was added to 40 g of N,N-dimethylformamide, and then 7.7 g of intermediate product B was added, and the mixture was heated to 90°C for reaction for 24 h. After the reaction was completed, the mixture was distilled and chromatographed on a petroleum ether column to obtain intermediate product C.

[0052] Step S3, at room temperature, add 2.6 g of the intermediate product C to 120 g of methanol, then add 2.5 g of 4,4'-(hydroxyphosphoryl)dibenzoic acid, and dropwise add 22.5 mL of a 0.07 g / L methanol solution of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide while stirring, and stir to react for 25 h. After the reaction is completed, filter, wash, and dry to obtain an intermediate product D;

[0053] Mix 33.8 g of intermediate product D and 250 g of ethylene glycol, heat to 50°C, add 0.9 g of sodium carbonate, stir and react until no gas is released, then adjust the pressure to 70 Pa and heat to 60°C, stir and react until no gas is released, cool, filter, wash and dry to obtain a functional additive.

[0054] Example 2

[0055] This embodiment discloses a method for preparing high enthalpy non-drip nylon 66 filaments, comprising the following steps:

[0056] Step (1), adding 2 g of boron nitride powder and 2 g of γ-glycidyloxypropyltrimethoxysilane to 80 g of ethanol, ultrasonically treating for 20 min, adding 15 g of deionized water, adjusting the pH of the mixed system to 4.5 with oxalic acid, heating to 55° C. and stirring for 100 min, filtering, washing, and drying to obtain epoxy-modified boron nitride;

[0057] 2.5 g of epoxy-modified boron nitride was added to 50 g of N,N-dimethylformamide and stirred, and then 0.8 g of 1-amino-3-butene-2-ol was added, and the mixture was stirred and reacted at 70° C. for 20 h. After the reaction was completed, the mixture was centrifuged, washed, and dried to obtain functionalized boron nitride;

[0058] Step (2), dissolving 4.5 g of sodium dodecyl sulfate in 100 g of deionized water to form an aqueous phase; mixing 50 g of methyl methacrylate, 10 g of pentaerythritol tetraacrylate, 50 g of octadecane, 0.1 g of azobisisobutyronitrile, and 10 g of functionalized boron nitride, and ultrasonicating for 20 min to form an oil phase; mixing the oil phase and the aqueous phase, stirring and dispersing at 33° C. at a speed of 2800 r / min for 20 min to form an oil-in-water emulsion; stirring the oil-in-water emulsion in a water bath at 80° C. at a speed of 500 r / min for 7 h, filtering, washing, and drying to obtain phase change microcapsules;

[0059] Step (3), mixing 2-hydroxyethyl acrylate, hydrogen peroxide, and water to obtain a treatment solution, adding nylon 66 powder to the treatment solution at 63° C., soaking for 80 minutes, filtering, washing, and drying to obtain grafted modified nylon 66, wherein the mass ratio of 2-hydroxyethyl acrylate, hydrogen peroxide, water, and nylon 66 powder is 5:0.25:11.4:10;

[0060] 8.8g of isophorone diisocyanate and 0.03g of dibutyltin dilaurate were added to 50g of acetone, heated to 55°C, 15g of grafted modified nylon 66 was added, stirred and reacted for 3h, and then 5g of phase change microcapsules were added. After the -NCO reaction was completed, the acetone was evaporated to obtain phase change modified nylon 66;

[0061] Step (4), the phase change modified nylon 66 and the functional additive are mixed and melt-extruded in a mass ratio of 1:0.1, melt-spinned at 250°C, and then water-cooled, oiled, hot-drawn and air-cooled and wound to obtain high thermal enthalpy non-melting nylon 66 filaments.

[0062] Example 3

[0063] This embodiment discloses a method for preparing high enthalpy non-drip nylon 66 filaments, comprising the following steps:

[0064] Step (1), adding 3g of boron nitride powder and 3g of γ-glycidyloxypropyltrimethoxysilane to 120g of ethanol, ultrasonically treating for 40min, adding 25g of deionized water, adjusting the pH of the mixed system to 5.5 with oxalic acid, heating to 65°C and stirring for 150min, filtering, washing, and drying to obtain epoxy-modified boron nitride; adding 3.5g of epoxy-modified boron nitride to 100g of N,N-dimethylformamide and stirring, then adding 1.5g of 1-amino-3-butene-2-ol, continuing to stir and react at 90°C for 20h, after the reaction is completed, centrifuging, washing, and drying to obtain functionalized boron nitride;

[0065] Step (2), dissolving 10.5 g of sodium dodecyl sulfate in 200 g of deionized water to form an aqueous phase; mixing 100 g of methyl methacrylate, 20 g of pentaerythritol tetraacrylate, 100 g of octadecane, 5 g of azobisisobutyronitrile, and 20 g of functionalized boron nitride, and ultrasonicating for 40 min to form an oil phase; mixing the oil phase and the aqueous phase, stirring and dispersing at 38° C. at a speed of 2800 r / min for 10 min to form an oil-in-water emulsion; stirring the oil-in-water emulsion in a 90° C. water bath at a speed of 700 r / min for 5 h, filtering, washing, and drying to obtain phase change microcapsules;

[0066] Step (3), mixing 2-hydroxyethyl acrylate, hydrogen peroxide, and water to obtain a treatment solution, adding nylon 66 powder to the treatment solution at 68° C., soaking for 120 minutes, filtering, washing, and drying to obtain grafted modified nylon 66, wherein the mass ratio of 2-hydroxyethyl acrylate, hydrogen peroxide, water, and nylon 66 powder is 15:0.75:34.2:10;

[0067] 13.2g of isophorone diisocyanate and 0.06g of dibutyltin dilaurate were added to 80g of acetone, heated to 60°C, 25g of grafted modified nylon 66 was added, stirred and reacted for 5h, and then 15g of phase change microcapsules were added. After the -NCO reaction was completed, the acetone was evaporated to obtain phase change modified nylon 66;

[0068] Step (4), the phase change modified nylon 66 and the functional additive are mixed and melt-extruded in a mass ratio of 1:0.4, melt-spinned at 260° C., and then water-cooled, oiled, hot-drawn and air-cooled and wound to obtain high thermal enthalpy non-melting nylon 66 filaments.

[0069] Example 4

[0070] This embodiment discloses a method for preparing high enthalpy non-drip nylon 66 filaments, comprising the following steps:

[0071] Step (1), adding 2.5 g of boron nitride powder and 2.5 g of γ-glycidyloxypropyltrimethoxysilane to 100 g of ethanol, ultrasonically treating for 30 min, adding 20 g of deionized water, adjusting the pH of the mixed system to 5 with oxalic acid, heating to 60 ° C and stirring for 120 min, filtering, washing, and drying to obtain epoxy-modified boron nitride; adding 3 g of epoxy-modified boron nitride to 75 g of N, N-dimethylformamide and stirring, then adding 1.2 g of 1-amino-3-butene-2-ol, continuing to stir and react at 80 ° C for 25 h, after the reaction is completed, centrifuging, washing, and drying to obtain functionalized boron nitride;

[0072] Step (2), dissolving 7.5 g of sodium dodecyl sulfate in 150 g of deionized water to form an aqueous phase; mixing 75 g of methyl methacrylate, 15 g of pentaerythritol tetraacrylate, 75 g of octadecane, 0.8 g of azobisisobutyronitrile, and 15 g of functionalized boron nitride, and ultrasonicating for 30 min to form an oil phase; mixing the oil phase and the aqueous phase, stirring and dispersing at 35° C. at a speed of 3000 r / min for 15 min to form an oil-in-water emulsion; stirring the oil-in-water emulsion in a water bath at 85° C. at a speed of 600 r / min for 6 h, filtering, washing, and drying to obtain phase change microcapsules;

[0073] Step (3), mixing 2-hydroxyethyl acrylate, hydrogen peroxide, and water to obtain a treatment solution, adding nylon 66 powder to the treatment solution at 65° C., soaking for 100 minutes, filtering, washing, and drying to obtain grafted modified nylon 66, wherein the mass ratio of 2-hydroxyethyl acrylate, hydrogen peroxide, water, and nylon 66 powder is 10:0.5:22.8:10;

[0074] 11g of isophorone diisocyanate and 0.04g of dibutyltin dilaurate were added to 65g of acetone, heated to 58°C, 20g of grafted modified nylon 66 was added, stirred and reacted for 4h, and then 10g of phase change microcapsules were added. After the -NCO reaction was completed, the acetone was evaporated to obtain phase change modified nylon 66;

[0075] Step (4), the phase change modified nylon 66 and the functional additive are mixed and melt-extruded at a mass ratio of 1:0.25, melt-spinned at 255° C., and then water-cooled, oiled, hot-drawn and air-cooled and wound to obtain high thermal enthalpy non-melting nylon 66 filaments.

[0076] The functional additives in the above Examples 2-4 are the functional additives prepared in Example 1.

[0077] Comparative Example 1

[0078] Compared with Example 1, in Comparative Example 1, in the process of preparing intermediate product C, intermediate product A is used instead of intermediate product B, that is, the functional additive in this comparative example does not contain a porphyrin ring, and other conditions remain unchanged.

[0079] Comparative Example 2

[0080] Compared with Example 4, in the process of preparing high thermal enthalpy non-drip nylon 66 filaments, Comparative Example 2 uses the functional additive prepared in Comparative Example 1, and other conditions remain unchanged.

[0081] Comparative Example 3

[0082] Compared with Example 4, in Comparative Example 3, in the process of preparing high thermal enthalpy non-drip nylon 66 filaments, the intermediate product C is used to replace the functional additive, and other conditions remain unchanged.

[0083] Comparative Example 4

[0084] Compared with Example 4, in the process of preparing high thermal enthalpy non-drip nylon 66 filaments, Comparative Example 4 uses intermediate product D instead of functional additives, and other conditions remain unchanged.

[0085] Comparative Example 5

[0086] Comparative Example 5 Compared with Example 4, in the process of preparing phase change microcapsules in Comparative Example 5, boron nitride powder is used instead of functionalized boron nitride, and other conditions remain unchanged.

[0087] Comparative Example 6

[0088] Comparative Example 6 Compared with Example 4, in the process of preparing the phase change microcapsules in Comparative Example 6, no functionalized boron nitride was added, and other conditions remained unchanged.

[0089] Comparative Example 7

[0090] Compared with Example 4, in Comparative Example 7, during the preparation of phase change modified nylon 66, the phase change microcapsules and the grafted modified nylon 66 were directly mixed, and the two were not cross-linked by isophorone diisocyanate, and other conditions remained unchanged.

[0091] In the above embodiments and comparative examples, the boron nitride powder, CAS No. 10043-11-5, particle size 30-50nm, properties: white loose powder, solubility: insoluble in water, comes from Hebei Teng Bimetallic Materials Co., Ltd.; nylon 66 powder, density 1.12-1.16g / cm3, shrinkage rate 0.8-1.2%, heat deformation temperature 100°C, water absorption rate>2.0%, comes from Shanghai Fangang Plastic Raw Materials Co., Ltd.

[0092] Experimental example

[0093] The performance of high enthalpy non-drip nylon 66 filaments of Examples 2-4 and Comparative Examples 2-7 was tested.

[0094] 1. Flame retardancy test: The limiting oxygen index of each group of nylon 66 filament samples was measured by ZR-1 intelligent oxygen index tester to characterize the flame retardancy.

[0095] 2. Anti-melt drop test: The UL-94 vertical burning test machine (CZF-5) was used to study the melt drop of each group of nylon 66 filament samples.

[0096] 3. Differential Scanning Calorimeter (DSC) Test: Wash the nylon 66 filament sample with water 50 times, cut it into pieces, weigh 5-10 mg and place it in an aluminum crucible. The protective gas is nitrogen, the heating rate is 10℃ / min, the temperature range is 0-50℃, and the melting enthalpy of the sample is measured by DSC test.

[0097] The test results are shown in Table 1:

[0098] Table 1

[0099]

[0100] It can be seen from the test results in Table 1 that the high enthalpy non-melting nylon 66 filaments prepared in Examples 2-4 of the present invention have high enthalpy, excellent flame retardant and anti-melting dripping properties, and the melting enthalpy is still 59 J / g after 50 water washings, showing good water washing resistance. From the comparison between Comparative Example 2 and Example 4, it can be seen that the porphyrin ring in the functional additive promotes carbonization by increasing the content of flame retardant element nitrogen and the melt viscosity and strength of nylon 66, thereby achieving the flame retardant and anti-melting dripping effect; from the comparison between Comparative Examples 3-4 and Example 4, it can be seen that the phosphorus-containing ion groups in the functional additive provide flame retardant element phosphorus and promote the formation of ion aggregation, thereby improving the flame retardancy and anti-melting dripping properties of nylon 66 filaments; from the comparison between Comparative Examples 5-6 and Example 4, it can be seen that boron nitride as a wall material additive can prevent the microcapsule shell from being damaged in subsequent processing to cause the leakage of the phase change material octadecane, thereby enhancing the thermal stability of the microcapsule wall material The phase change microcapsules are uniformly distributed in the wall material, and the phase change microcapsules are uniformly distributed in the nylon 66 filaments, and the connection strength between the phase change microcapsules and the grafted modified nylon 66 is improved, thereby improving the water washing resistance of the nylon 66 filaments and preventing the decrease of the thermal enthalpy value due to the shedding of the phase change microcapsules during the water washing process.

[0101] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing high enthalpy non-drip nylon 66 filament, characterized in that: The following steps are involved: Step (1), first modifying boron nitride to obtain epoxy-modified boron nitride, and reacting the epoxy-modified boron nitride with 1-amino-3-butene-2-ol to obtain functionalized boron nitride; Step (2), using octadecane as the core material, methyl methacrylate as the wall material, pentaerythritol tetraacrylate as the wall material crosslinking agent, and functionalized boron nitride as the wall material additive to prepare phase change microcapsules; Step (3), grafting nylon 66 with 2-hydroxyethyl acrylate to obtain grafted modified nylon 66; Phase change microcapsules were combined with grafted nylon 66 using isophorone diisocyanate as a crosslinking agent to obtain phase change modified nylon 66. Step (4), the phase change modified nylon 66 and the functional additive are mixed and melt-extruded, melt-spinned, and then water-cooled, oiled, hot-drawn and air-cooled and wound to obtain high thermal enthalpy non-melting nylon 66 filaments; The method for preparing the functional additive comprises the following steps: Step S1, modifying citric acid with thionyl chloride to obtain modified citric acid, and reacting the modified citric acid with p-hydroxybenzaldehyde to obtain an intermediate product A; Step S2, the intermediate product A reacts with pyrrole to obtain an intermediate product B; the intermediate product B reacts with ethylenediamine to obtain an intermediate product C; Step S3: the intermediate product C reacts with 4,4'-(hydroxyphosphoryl)dibenzoic acid to obtain an intermediate product D; the intermediate product D reacts with ethylene glycol and sodium carbonate to obtain a functional additive.

2. The method for preparing high enthalpy non-drip nylon 66 filament according to claim 1, characterized in that: In the step (1), the epoxy-modified boron nitride is prepared by the following method: adding boron nitride powder and γ-glycidyloxypropyltrimethoxysilane to ethanol, ultrasonically treating for 20-40 minutes, adding deionized water, adjusting the pH of the mixed system to 4.5-5.5 with oxalic acid, heating to 55-65°C and stirring for 100-150 minutes, filtering, washing, and drying, wherein the mass ratio of boron nitride powder, γ-glycidyloxypropyltrimethoxysilane, ethanol, and deionized water is (2-3):(2-3):(80-120):(15-25).

3. The method for preparing high enthalpy non-drip nylon 66 filament according to claim 1, characterized in that: In the step (1), the preparation method of the functionalized boron nitride is as follows: epoxy-modified boron nitride is added to N,N-dimethylformamide and stirred, and then 1-amino-3-butene-2-ol is added, and the reaction is continued at 70-90°C with stirring for 20-30 hours. After the reaction is completed, centrifugation, washing, and drying are performed, wherein the mass ratio of epoxy-modified boron nitride, N,N-dimethylformamide, and 1-amino-3-butene-2-ol is (2.5-3.5):(50-100):(0.8-1.5).

4. The method for preparing high enthalpy non-drip nylon 66 filament according to claim 1, characterized in that: In the step (2), the preparation method of the phase change microcapsule is as follows: the oil phase and the water phase are mixed, and the mixture is stirred and dispersed at a speed of 2800-3200 r / min at 33-38°C for 10-20 min to form an oil-in-water emulsion; the oil-in-water emulsion is stirred in a water bath at 80-90°C at a speed of 500-700 r / min for 5-7 h, filtered, washed, and dried.

5. The method for preparing high enthalpy non-drip nylon 66 filament according to claim 4, characterized in that: In the step (2), the aqueous phase is obtained by mixing sodium dodecyl sulfate and deionized water in a mass ratio of (4.5-10.5):(100-200); the oil phase is obtained by mixing methyl methacrylate, pentaerythritol tetraacrylate, octadecane, azobisisobutyronitrile, and functionalized boron nitride in a mass ratio of (50-100):(10-20):(50-100):(0.1-5):(10-20), and the mixture is ultrasonicated for 20-40 minutes.

6. The method for preparing high enthalpy non-drip nylon 66 filament according to claim 1, characterized in that: In the step (3), the preparation method of the grafted modified nylon 66 is as follows: 2-hydroxyethyl acrylate, hydrogen peroxide and water are mixed to obtain a treatment liquid, nylon 66 powder is added to the above treatment liquid at 63-68°C, soaked for 80-120 minutes, filtered, washed and dried to obtain grafted modified nylon 66, wherein the mass ratio of 2-hydroxyethyl acrylate, hydrogen peroxide, water and nylon 66 powder is (5-15):(0.25-0.75):(11.4-34.2):

10.

7. The method for preparing high enthalpy non-drip nylon 66 filament according to claim 1, characterized in that: In the step (4), the preparation method of the phase change modified nylon 66 is as follows: adding isophorone diisocyanate and dibutyltin dilaurate to acetone, heating to 55-60°C, adding grafted modified nylon 66, stirring to react for 3-5 hours, and then adding phase change microcapsules. After the -NCO reaction is completed, evaporating and removing the acetone; wherein the mass ratio of isophorone diisocyanate, dibutyltin dilaurate, acetone, grafted modified nylon 66, and phase change microcapsules is (8.8-13.2):(0.03-0.06):(50-80):(15-25):(5-15).

8. The method for preparing high enthalpy non-drip nylon 66 filament according to claim 1, characterized in that: In the step (4), the mass ratio of the phase change modified nylon 66 to the functional additive is 1:(0.1-0.4); and the melt spinning temperature is 250-260°C.

9. The method for preparing high enthalpy non-drip nylon 66 filament according to claim 1, characterized in that: In the step (4), the preparation method of the functional additive is: Step S1, adding citric acid to tetrahydrofuran, then adding thionyl chloride, heating to 57-63°C for reaction for 20-30h, after the reaction is completed, evaporating to remove the solvent and excess thionyl chloride to obtain modified citric acid, wherein the mass ratio of citric acid, tetrahydrofuran and thionyl chloride is (1.9-3.8):(30-50):(4.2-8.5); Add modified citric acid to ethanol, stir for 10-30 minutes, then add p-hydroxybenzaldehyde, react at room temperature for 20-25 hours, and after the reaction is completed, evaporate and remove the solvent to obtain an intermediate product A; wherein the mass ratio of modified citric acid, ethanol, and p-hydroxybenzaldehyde is (2.5-5):(40-50):(1.2-2.5); Step S2, adding the intermediate product A to a mixed solution of propionic acid and propionic anhydride, adding dropwise a 9.2wt% pyrrole / propionic acid mixed solution at a rate of 0.8-1.2mL / min at 145-155°C, reacting for 3.5-4.5h in a nitrogen atmosphere, and after the reaction, removing the solvent by rotary evaporation, and obtaining an intermediate product B by petroleum ether column chromatography; wherein the mass ratio of the intermediate product A, propionic acid, propionic anhydride, and pyrrole / propionic acid mixed solution is (4.7-9.4):(100-200):(40-80):(22-44); Add ethylenediamine to N,N-dimethylformamide, then add intermediate product B, heat to 80-100°C and react for 20-26 hours. After the reaction is completed, distill and chromatograph by petroleum ether column to obtain intermediate product C; wherein the mass ratio of ethylenediamine, N,N-dimethylformamide and intermediate product B is (2-3.5):(30-50):(5.1-10.2); Step S3, at room temperature, adding the intermediate product C to methanol, then adding 4,4'-(hydroxyphosphoryl)dibenzoic acid, and dropping a methanol solution of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide at a concentration of 0.07 g / L while stirring, stirring for 20-30 hours, and after the reaction is completed, filtering, washing, and drying to obtain an intermediate product D; wherein the amount ratio of the intermediate product C, methanol, 4,4'-(hydroxyphosphoryl)dibenzoic acid, and the methanol solution of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide is (1.7-3.4) g:(80-150) g:(1.5-3.5) g:(15-30) mL; The intermediate product D and ethylene glycol are mixed, heated to 45-55°C, and sodium carbonate is added, and the reaction is stirred until no gas is released, and then the pressure is adjusted to 40-100 Pa and heated to 55-65°C, and the reaction is stirred until no gas is released, and the mixture is cooled, filtered, washed, and dried to obtain a functional additive; wherein the mass ratio of the intermediate product D, ethylene glycol, and sodium carbonate is (22.5-45):(200-300):(0.6-1.2).

10. A high enthalpy non-drip nylon 66 filament prepared by the method for preparing high enthalpy non-drip nylon 66 filament according to any one of claims 1 to 9.

Images