Phosphorus-containing flame retardant modified attapulgite modified polyethylene fiber and preparation method thereof

Abstract

The invention relates to the technical field of polyethylene, and discloses a phosphorus-containing flame retardant modified attapulgite modified polyethylene fiber, epoxidized attapulgite reacts with polyethylene glycol terephthalate to obtain polyethylene glycol terephthalate modified attapulgite, and the polyethylene glycol terephthalate modified attapulgite reacts with toluene-2, 4-diisocyanate to obtain the phosphorus-containing flame retardant modified attapulgite modified polyethylene fiber. The preparation method comprises the following steps: carrying out a reaction on isocyanate esterified polyethylene glycol terephthalate modified attapulgite and dibenzyl phosphite to obtain dibenzyl phosphite-based polyethylene glycol terephthalate modified attapulgite, blending the dibenzyl phosphite-based polyethylene glycol terephthalate modified attapulgite with polyethylene, and carrying out a melt spinning method to obtain the phosphorus-containing flame retardant modified attapulgite modified polyethylene fiber. The polyethylene glycol terephthalate and the attapulgite can absorb and disperse stress, oxyacid of phosphorus can be generated after the dibenzyl phosphite is combusted, a carbon layer formed on the surface of the composite wood-plastic plate is promoted, the attapulgite can be deposited on the surface of the carbon layer, the gas barrier property and other properties of the carbon layer are enhanced, and therefore the flame retardant property of the composite wood-plastic plate is improved.

Description

Technical Field

[0001] The invention relates to the technical field of polyethylene, in particular to a phosphorus-containing flame retardant-modified attapulgite-modified polyethylene fiber and a preparation method thereof. Background Art

[0002] In today's fast-paced living environment, people are more and more particular about their clothes, which has led to widespread attention to the performance of fiber-making fabrics. Polyethylene fiber has excellent properties such as low density and strong insulation, which makes it widely used in filter materials, tarpaulins, mesh belts and other fields. However, the polyethylene matrix itself is brittle and has low strength, so traditional polyethylene needs to be modified. In recent years, polyethylene has been modified by filling with inorganic nanomaterials and blending with organic polymer materials. By combining the excellent properties of inorganic nanomaterials and organic polymer materials, the mechanical, flame retardant and other comprehensive properties of polyethylene are improved, and the application range of polyethylene wood-plastic boards is expanded, which has become a research hotspot for researchers.

[0003] Attapulgite is a natural hydrated magnesium aluminum silicate nanoclay mineral with abundant reserves in China. It is currently widely used in industrial fields such as catalysis and adsorption. With the deepening of research, people have found that attapulgite can be used as a good polymer reinforcement material. Chinese patents such as CN106674686A and CN112063029A disclose a feasible method for blending attapulgite with polyethylene to form a hybrid composite material with high mechanical strength. However, most of these patents do not modify the attapulgite, do not solve the problem of the single functionality of attapulgite, and the hydrophilicity and easy agglomeration problems of attapulgite have not been well solved. Therefore, it is necessary to modify the attapulgite, and further introduce organic polymers with strengthening and toughening effects or flame retardant small molecules such as diphenyl phosphite through the hydroxyl groups on its surface, which can effectively enhance the functionality of the attapulgite and further expand the application range of the attapulgite. Summary of the invention

[0004] In view of the shortcomings of the prior art, the present invention provides a phosphorus-containing flame retardant-modified attapulgite-modified polyethylene fiber and a preparation method, which solves the problem of poor toughness and flame retardancy of the polyethylene fiber.

[0005] To achieve the above object, the present invention provides the following technical solution: a phosphorus-containing flame retardant-modified attapulgite-modified polyethylene fiber, and the preparation method of the phosphorus-containing flame retardant-modified attapulgite-modified polyethylene fiber comprises the following steps: (1) adding toluene solvent, attapulgite and 3-glycidyloxypropyltrimethoxysilane in a mass ratio of 150-600:10:0.6-2 into a reactor, mixing evenly and transferring to an oil bath, reacting at 40-60° C. for 2-6 hours, centrifuging after the reaction, washing and drying to obtain epoxidized attapulgite; (2) adding epoxidized attapulgite and polyethylene terephthalate into a torque rheometer, mixing them evenly, setting the rotor speed to 30-50 r / min, reacting, cooling the product, washing and drying it, and obtaining polyethylene terephthalate modified attapulgite; (3) adding tetrachloroethane and polyethylene terephthalate modified attapulgite into a reactor, dispersing by ultrasonic until completely dissolved, then adding toluene-2,4-diisocyanate and dibutyltin dilaurate, mixing evenly and transferring to an oil bath, reacting at 60-80° C. for 4-12 h, centrifuging after the reaction, washing and drying to obtain isocyanate polyethylene terephthalate modified attapulgite; (4) Add tetrachloroethane, acetonitrile, diphenyl phosphite and potassium hydroxide to the reactor, mix well and transfer to an oil bath, raise the temperature to 70-90°C and reflux for 1-2 hours, continue to add isocyanate-modified polyethylene terephthalate attapulgite, stir and react for 4-8 hours, centrifuge after the reaction, wash and dry to obtain dibenzyl phosphite-based polyethylene terephthalate modified attapulgite; (5) Add polyethylene and dibenzyl phosphite-based polyethylene terephthalate-modified attapulgite into a single-screw extruder, mix well and then melt-extrude, transfer to a melt spinning machine for spinning, and obtain phosphorus-containing flame retardant-modified attapulgite-modified polyethylene fibers.

[0006] Preferably, in step (2), the mass ratio of epoxidized attapulgite to polyethylene terephthalate is 10:25-60.

[0007] Preferably, the reaction temperature in step (2) is 240-260° C. and the reaction time is 20-40 min.

[0008] Preferably, in step (3), the mass ratio of tetrachloroethane, polyethylene terephthalate-modified attapulgite, toluene-2,4-diisocyanate and dibutyltin dilaurate is 300-850:10:0.5-1.4:0.02-0.06.

[0009] Preferably, in step (4), the mass ratio of tetrachloroethane, acetonitrile, diphenyl phosphite, potassium hydroxide and isocyanate-modified attapulgite is 200-600:60-150:1.2-3:0.3-0.8:10.

[0010] Preferably, in step (5), the mass ratio of polyethylene to dibenzyl phosphite-based polyethylene terephthalate modified attapulgite is 100:2-8.

[0011] Compared with the prior art, the present invention has the following beneficial technical effects: The phosphorus-containing flame retardant-modified attapulgite-modified polyethylene fiber has a large number of epoxy groups on the surface of the attapulgite modified by 3-glycidyloxypropyltrimethoxysilane, which can undergo a ring-opening reaction with the carboxyl groups in polyethylene terephthalate under high temperature conditions to obtain polyethylene terephthalate-modified attapulgite. Under the catalytic action of the catalyst dibutyltin dilaurate, the terminal hydroxyl groups in the polyethylene terephthalate can react with the isocyanate groups in toluene-2,4-diisocyanate. The reaction can obtain isocyanated polyethylene terephthalate modified attapulgite, and the pH in dibenzyl phosphite can react with the isocyanate group in the isocyanated polyethylene terephthalate modified attapulgite after being activated by potassium hydroxide to obtain dibenzyl phosphite-based polyethylene terephthalate modified attapulgite, thereby chemically bonding the polyethylene terephthalate macromolecules and the dibenzyl phosphite flame retardant small molecules to the surface of the attapulgite, effectively expanding the functionality and application range of the attapulgite.

[0012] The phosphorus-containing flame retardant modified attapulgite modified polyethylene fiber is prepared by melt blending polyethylene and dibenzyl phosphite-based polyethylene terephthalate modified attapulgite, and then using a melt spinning method to finally obtain the phosphorus-containing flame retardant modified attapulgite modified polyethylene fiber. Polyethylene terephthalate serves as a flexible long chain, which can improve the flexibility of the composite polyethylene wood-plastic board and enhance the ability of the composite wood-plastic board to absorb plastic deformation work caused by external stress. In addition, the fiber is more likely to rub against the polyethylene matrix, thereby improving the tensile strength and other mechanical properties of the composite wood-plastic board to a certain extent. , and attapulgite itself can also absorb part of the stress energy, thereby further enhancing the toughness of the composite wood-plastic board. In addition, the dibenzyl phosphite group grafted on the surface of attapulgite will generate a large amount of phosphorus oxygen-containing acid when burning, which catalyzes the polyethylene matrix into carbon, and then forms a dense carbon layer on the surface of the composite wood-plastic board to protect the inside of the matrix from further combustion. The silicate minerals generated after the combustion of attapulgite will be deposited on the surface of the carbon layer, enhancing the gas barrier and other properties of the carbon layer. By combining the synergistic flame retardant effect of dibenzyl phosphite and attapulgite, the flame retardant properties of the composite wood-plastic board are further improved. DETAILED DESCRIPTION

[0013] To achieve the above object, the present invention provides the following specific implementation methods and examples: A phosphorus-containing flame retardant-modified attapulgite-modified polyethylene fiber, the preparation method of which comprises the following steps: (1) adding toluene solvent, attapulgite and 3-glycidyloxypropyltrimethoxysilane in a mass ratio of 150-600:10:0.6-2 into a reactor, mixing evenly and transferring to an oil bath, reacting at 40-60° C. for 2-6 hours, centrifuging after the reaction, washing and drying to obtain epoxidized attapulgite; (2) Add epoxidized attapulgite and polyethylene terephthalate in a mass ratio of 10:25-60 into a torque rheometer, mix well, set the rotor speed to 30-50 r / min, react at 240-260° C. for 20-40 min, wash and dry the product after cooling, and obtain polyethylene terephthalate modified attapulgite; (3) adding tetrachloroethane and polyethylene terephthalate modified attapulgite into a reactor, dispersing them by ultrasonic until they are completely dissolved, and then adding toluene-2,4-diisocyanate and dibutyltin dilaurate, wherein the mass ratio of tetrachloroethane, polyethylene terephthalate modified attapulgite, toluene-2,4-diisocyanate and dibutyltin dilaurate is 300-850:10:0.5-1.4:0.02-0.06, mixing them evenly and transferring them to an oil bath pot, reacting them at 60-80°C for 4-12h, centrifuging, washing and drying after the reaction to obtain isocyanate polyethylene terephthalate modified attapulgite; (4) adding tetrachloroethane, acetonitrile, diphenyl phosphite and potassium hydroxide to the reactor, mixing well and transferring to an oil bath, raising the temperature to 70-90°C and reflux for 1-2h, and continuing to add isocyanate-modified polyethylene terephthalate attapulgite, wherein the mass ratio of tetrachloroethane, acetonitrile, diphenyl phosphite, potassium hydroxide and isocyanate-modified polyethylene terephthalate attapulgite is 200-600:60-150:1.2-3:0.3-0.8:10, stirring and reacting for 4-8h, centrifuging after the reaction, washing and drying to obtain dibenzyl phosphite-based polyethylene terephthalate modified attapulgite; (5) Adding polyethylene and dibenzyl phosphite-based polyethylene terephthalate-modified attapulgite in a mass ratio of 100:2-8 into a single-screw extruder, mixing them evenly and then melt-extruding them, and transferring them to a melt spinning machine for spinning to obtain phosphorus-containing flame retardant-modified attapulgite-modified polyethylene fibers. Example 1

[0014] (1) Add 90 mL of toluene solvent, 5 g of attapulgite and 0.3 g of 3-glycidyloxypropyltrimethoxysilane into a reactor, mix well and transfer to an oil bath, react at 40 ° C for 2 h, centrifuge after the reaction, wash and dry to obtain epoxidized attapulgite; (2) Add 5 g of epoxidized attapulgite and 12.5 g of polyethylene terephthalate into the torque rheometer, mix them evenly, set the rotor speed to 30 r / min, react at 240 °C for 20 min, cool the product, wash and dry it to obtain polyethylene terephthalate modified attapulgite; (3) Add 95 mL of tetrachloroethane and 5 g of polyethylene terephthalate-modified attapulgite into the reactor, disperse by ultrasonic until completely dissolved, then add 0.25 g of toluene-2,4-diisocyanate and 0.01 g of dibutyltin dilaurate, mix well and transfer to an oil bath, react at 60 ° C for 4 h, centrifuge after the reaction, wash and dry to obtain isocyanate-modified polyethylene terephthalate-modified attapulgite; (4) Add 65 mL of tetrachloroethane, 40 mL of acetonitrile, 0.6 g of diphenyl phosphite and 0.15 g of potassium hydroxide to the reactor, mix well and transfer to an oil bath, raise the temperature to 70 ° C and reflux for 1 hour, continue to add 5 g of isocyanate-modified polyethylene terephthalate attapulgite, stir and react for 4 hours, centrifuge after the reaction, wash and dry to obtain dibenzyl phosphite-based polyethylene terephthalate modified attapulgite; (5) Add 50 g of polyethylene and 1 g of dibenzyl phosphite-based polyethylene terephthalate-modified attapulgite into a single-screw extruder, mix well and then melt-extrude, transfer to a melt spinning machine for spinning, and obtain phosphorus-containing flame retardant-modified attapulgite-modified polyethylene fibers. Example 2

[0015] (1) Add 160 mL of toluene solvent, 5 g of attapulgite and 0.5 g of 3-glycidyloxypropyltrimethoxysilane into a reactor, mix well and transfer to an oil bath, react at 45 °C for 3 h, centrifuge after the reaction, wash and dry to obtain epoxidized attapulgite; (2) Add 5 g of epoxidized attapulgite and 18 g of polyethylene terephthalate into the torque rheometer, mix them evenly, set the rotor speed to 35 r / min, react at 245 °C for 25 min, cool the product, wash and dry it to obtain polyethylene terephthalate modified attapulgite; (3) Add 140 mL of tetrachloroethane and 5 g of polyethylene terephthalate-modified attapulgite into the reactor, disperse by ultrasonic until completely dissolved, then add 0.4 g of toluene-2,4-diisocyanate and 0.015 g of dibutyltin dilaurate, mix well and transfer to an oil bath, react at 65 °C for 6 h, centrifuge after the reaction, wash and dry to obtain isocyanate-modified polyethylene terephthalate-modified attapulgite; (4) Add 80 mL of tetrachloroethane, 60 mL of acetonitrile, 0.8 g of diphenyl phosphite and 0.2 g of potassium hydroxide into the reactor, mix well and transfer to an oil bath, raise the temperature to 75 ° C and reflux for 1 hour, continue to add 5 g of isocyanate-modified polyethylene terephthalate attapulgite, stir and react for 5 hours, centrifuge after the reaction, wash and dry to obtain dibenzyl phosphite-based polyethylene terephthalate modified attapulgite; (5) Add 50 g of polyethylene and 2 g of dibenzyl phosphite-based polyethylene terephthalate-modified attapulgite into a single-screw extruder, mix well and then melt-extrude, transfer to a melt spinning machine for spinning, and obtain phosphorus-containing flame retardant-modified attapulgite-modified polyethylene fibers. Example 3

[0016] (1) Add 240 mL of toluene solvent, 5 g of attapulgite and 0.7 g of 3-glycidyloxypropyltrimethoxysilane into a reactor, mix well and transfer to an oil bath, react at 50 ° C for 4 h, centrifuge after the reaction, wash and dry to obtain epoxidized attapulgite; (2) Add 5 g of epoxidized attapulgite and 22 g of polyethylene terephthalate into the torque rheometer, mix them evenly, set the rotor speed to 40 r / min, react at 250°C for 30 min, cool the product, wash and dry it to obtain polyethylene terephthalate modified attapulgite; (3) Add 180 mL of tetrachloroethane and 5 g of polyethylene terephthalate-modified attapulgite into the reactor, disperse by ultrasonic until completely dissolved, then add 0.5 g of toluene-2,4-diisocyanate and 0.02 g of dibutyltin dilaurate, mix well and transfer to an oil bath, react at 70 ° C for 8 h, centrifuge after the reaction, wash and dry to obtain isocyanate-modified polyethylene terephthalate-modified attapulgite; (4) Add 120 mL of tetrachloroethane, 80 mL of acetonitrile, 1 g of diphenyl phosphite and 0.26 g of potassium hydroxide to the reactor, mix well and transfer to an oil bath, raise the temperature to 80 ° C and reflux for 2 h, continue to add 5 g of isocyanate-modified polyethylene terephthalate attapulgite, stir and react for 6 h, centrifuge after the reaction, wash and dry to obtain dibenzyl phosphite-based polyethylene terephthalate modified attapulgite; (5) Add 50 g of polyethylene and 3 g of dibenzyl phosphite-based polyethylene terephthalate-modified attapulgite into a single-screw extruder, mix well and then melt-extrude, transfer to a melt spinning machine for spinning, and obtain phosphorus-containing flame retardant-modified attapulgite-modified polyethylene fibers. Example 4

[0017] (1) Add 340 mL of toluene solvent, 5 g of attapulgite and 1 g of 3-glycidyloxypropyltrimethoxysilane into a reactor, mix well and transfer to an oil bath, react at 60 ° C for 6 h, centrifuge after the reaction, wash and dry to obtain epoxidized attapulgite; (2) Add 5 g of epoxidized attapulgite and 30 g of polyethylene terephthalate into the torque rheometer, mix them evenly, set the rotor speed to 50 r / min, react at 260°C for 40 min, cool the product, wash and dry it to obtain polyethylene terephthalate modified attapulgite; (3) Add 265 mL of tetrachloroethane and 5 g of polyethylene terephthalate-modified attapulgite into the reactor, disperse by ultrasonic until completely dissolved, then add 0.7 g of toluene-2,4-diisocyanate and 0.03 g of dibutyltin dilaurate, mix well and transfer to an oil bath, react at 80 °C for 12 h, centrifuge after the reaction, wash and dry to obtain isocyanate-modified polyethylene terephthalate-modified attapulgite; (4) Add 185 mL of tetrachloroethane, 95 mL of acetonitrile, 1.5 g of diphenyl phosphite and 0.4 g of potassium hydroxide to the reactor, mix well and transfer to an oil bath, raise the temperature to 90 ° C and reflux for 2 h, continue to add 5 g of isocyanate-modified polyethylene terephthalate attapulgite, stir and react for 8 h, centrifuge after the reaction, wash and dry to obtain dibenzyl phosphite-based polyethylene terephthalate modified attapulgite; (5) Add 50 g of polyethylene and 4 g of dibenzyl phosphite-based polyethylene terephthalate-modified attapulgite into a single-screw extruder, mix well and then melt-extrude, transfer to a melt spinning machine for spinning, and obtain phosphorus-containing flame retardant-modified attapulgite-modified polyethylene fibers.

[0018] Comparative Example 1 (1) Add 100 mL of toluene solvent, 5 g of attapulgite and 0.4 g of 3-glycidyloxypropyltrimethoxysilane into a reactor, mix well and transfer to an oil bath, react at 45 °C for 3 h, centrifuge after the reaction, wash and dry to obtain epoxidized attapulgite; (2) Add 5 g of epoxidized attapulgite and 14 g of polyethylene terephthalate into the torque rheometer, mix them evenly, set the rotor speed to 35 r / min, react at 245 °C for 25 min, cool the product, wash and dry it to obtain polyethylene terephthalate modified attapulgite; (3) Add 50 g of polyethylene and 1.2 g of polyethylene terephthalate-modified attapulgite into a single-screw extruder, mix well, and then melt-extrude. The mixture is then transferred to a melt spinning machine for spinning to obtain attapulgite-modified polyethylene fibers.

[0019] Comparative Example 2 (1) Add 320 mL of toluene solvent, 5 g of attapulgite and 0.9 g of 3-glycidyloxypropyltrimethoxysilane into a reactor, mix well and transfer to an oil bath, react at 55 °C for 5 h, centrifuge after the reaction, wash and dry to obtain epoxidized attapulgite; (2) Add 50 g of polyethylene and 3.8 g of epoxidized attapulgite into a single-screw extruder, mix well and then melt-extrude, transfer to a melt spinning machine for spinning, and obtain attapulgite-modified polyethylene fibers.

[0020] The composite fibers in the examples and comparative examples were prepared into sample cloths with a size of 6 cm×6 cm, and the impact strength of the composite fibers was tested using a HH300-500J impact strength tester.

[0021]

[0022] The composite fibers in the embodiments and comparative examples were prepared into sample cloths with a specification of 6 cm×6 cm, which were placed in a JF-3 digital oxygen index tester. Air was introduced and ignited from the top after the gas was stable. The oxygen concentration was measured when it was half burned, and the limiting oxygen index was calculated.

[0023]

Claims

1. A phosphorus-containing flame retardant-modified attapulgite-modified polyethylene fiber, characterized in that: The following steps are involved: (1) Mixing toluene solvent, attapulgite and 3-glycidyloxypropyltrimethoxysilane in a mass ratio of 150-600:10:0.6-2, and transferring the mixture to an oil bath, reacting the mixture at 40-60°C for 2-6 hours, centrifuging, washing and drying the mixture after the reaction to obtain epoxidized attapulgite; (2) adding epoxidized attapulgite and polyethylene terephthalate into a torque rheometer, mixing them evenly, setting the rotor speed to 30-50 r / min, reacting, cooling the product, washing and drying it, and obtaining polyethylene terephthalate modified attapulgite; (3) Add polyethylene terephthalate modified attapulgite to tetrachloroethane solvent, disperse by ultrasonic until completely dissolved, then continue to add toluene-2,4-diisocyanate and dibutyltin dilaurate, mix well and transfer to an oil bath, react at 60-80°C for 4-12h, centrifuge after the reaction, wash and dry to obtain isocyanate polyethylene terephthalate modified attapulgite; (4) Add diphenyl phosphite and potassium hydroxide to a mixed solvent of tetrachloroethane and acetonitrile, mix well and transfer to an oil bath, raise the temperature to 70-90°C and reflux for 1-2 hours, continue to add isocyanate-modified polyethylene terephthalate attapulgite, stir and react for 4-8 hours, centrifuge after the reaction, wash and dry to obtain dibenzyl phosphite-based polyethylene terephthalate modified attapulgite; (5) Add polyethylene and dibenzyl phosphite-based polyethylene terephthalate-modified attapulgite into a single-screw extruder, mix well and then melt-extrude, transfer to a melt spinning machine for spinning, and obtain phosphorus-containing flame retardant-modified attapulgite-modified polyethylene fibers.

2. The phosphorus-containing flame retardant-modified attapulgite-modified polyethylene fiber according to claim 1, characterized in that: In the step (2), the mass ratio of epoxidized attapulgite to polyethylene terephthalate is 10:25-60.

3. The phosphorus-containing flame retardant-modified attapulgite-modified polyethylene fiber according to claim 1, characterized in that: The reaction temperature in step (2) is 240-260° C. and the reaction time is 20-40 min.

4. The phosphorus-containing flame retardant-modified attapulgite-modified polyethylene fiber according to claim 1, characterized in that: In the step (3), the mass ratio of tetrachloroethane, polyethylene terephthalate modified attapulgite, toluene-2,4-diisocyanate and dibutyltin dilaurate is 300-850:10:0.5-1.4:0.02-0.

06.

5. The phosphorus-containing flame retardant-modified attapulgite-modified polyethylene fiber according to claim 1, characterized in that: In the step (4), the mass ratio of tetrachloroethane, acetonitrile, diphenyl phosphite, potassium hydroxide and isocyanate-modified attapulgite is 200-600:60-150:1.2-3:0.3-0.8:

10.

6. The phosphorus-containing flame retardant-modified attapulgite-modified polyethylene fiber according to claim 1, characterized in that: In the step (5), the mass ratio of polyethylene to dibenzyl phosphite-based polyethylene terephthalate modified attapulgite is 100:2-8.

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