High temperature resistant fluoroelastomer processing aid for slurry polyethylene process and preparation method thereof

Abstract

The invention relates to the technical field of fluoroelastomer processing aids, and discloses a high-temperature resistant fluoroelastomer processing aid for a slurry polyethylene process and a preparation method thereof. The invention provides a high-temperature resistant fluoroelastomer processing aid for a slurry polyethylene process by adding graphene oxide modified epoxy resin, fluorine-containing modified epoxy resin and tetrafluoroethylene-vinylidene fluoride copolymer into a double screw extruder, extruding, crushing the extrudate, extracting with acetone, filtering and drying. The high-temperature resistant fluoroelastomer processing aid for a slurry polyethylene process is obtained. The epoxy resin has good temperature resistance, and the graphene oxide has good lubrication effect, so that the orifice of the die head will not be blocked. A large amount of fluoride contained by grafting can be applied to polyethylene to reduce friction between resins, delay shark skin melt fracture, make the surface smoother, and improve processing performance and material flow rate. The graphene oxide itself has good flame retardant effect, and the sulfur element in the additive is synergistic flame retardant.

Description

Technical Field

[0001] The invention relates to the technical field of fluoroelastomer processing aids, in particular to a high-temperature resistant fluoroelastomer processing aid used in a slurry polyethylene process and a preparation method thereof. Background Art

[0002] The low-pressure slurry polyethylene process is a process that connects a slurry loop and a gas-phase fluidized bed in series. It has two series reactors and has the ability to produce bimodal polyethylene. The first reactor is a loop slurry reactor, followed by a gas-phase fluidized bed reactor. During the extrusion and forming production process, the die mouth is often blocked, resulting in reduced product quality and efficiency and melt fracture. Graphene oxide itself has good lubrication and flame retardancy, which is inspired by reacting it with epoxy resin and fluorine-containing compounds to prepare a fluoroelastomer processing aid with excellent performance. Summary of the invention

[0003] 1. Technical issues to be resolved

[0004] In view of the deficiencies in the prior art, the present invention provides a processing aid and preparation method for high temperature resistant fluoroelastomers used in a slurry polyethylene process, which improves melt fracture, improves processing performance, and increases material flow rate, while also having a good flame retardant effect.

[0005] (II) Technical solution

[0006] To achieve the above-mentioned purpose, the present invention provides the following technical scheme: a processing aid for high temperature resistant fluoroelastomer in slurry polyethylene process, comprising the following components by weight: 4-8 parts by weight of graphene oxide modified epoxy resin, 10-25 parts by weight of fluorine-containing modified epoxy resin, and 40-60 parts by weight of tetrafluoroethylene-vinylidene fluoride copolymer.

[0007] Preferably, the preparation method of the graphene oxide modified epoxy resin is:

[0008] S1. Add water-based epoxy resin and ethylenediamine curing agent into a reactor, stir at high speed, add graphene oxide thereto, and perform ultrasonic treatment for 40-70 minutes to obtain graphene oxide-modified epoxy resin.

[0009] Preferably, the mass ratio of the waterborne epoxy resin, ethylenediamine curing agent and graphene oxide is 1:0.02-0.04:1.1-1.3.

[0010] Preferably, the preparation method of the fluorine-modified epoxy resin is:

[0011] (1) adding p-hydroxybenzaldehyde and o-aminotrifluorotoluene to N,N-dimethylformamide solvent, reacting at 75-90° C. for 8-12 hours, and then distilling under reduced pressure, filtering and drying to obtain intermediate 1;

[0012] (2) adding intermediate 1 and 4-amino-3-fluorobenzenethiol to N,N-dimethylformamide solvent, stirring evenly, then adding benzoin dimethyl ether photoinitiator thereto, irradiating with 365 nm ultraviolet light at 40-50° C. for 2-4 h, centrifuging, washing with distilled water, and drying to obtain intermediate 2;

[0013] (3) Add intermediate 2, polyethylene glycol, and epichlorohydrin to tetrahydrofuran solvent, stir and dissolve, then continue to add boron trifluoride ether catalyst, react at 20-25° C. for 2-4 hours, then continue to add sodium hydroxide to carry out ring-closing reaction, heat to 60-70° C. to react for 3-4 hours, centrifuge after completion, wash with n-hexane 2-3 times, and obtain fluorine-modified epoxy resin.

[0014] Preferably, the mass ratio of p-hydroxybenzaldehyde to o-aminotrifluorotoluene in (1) is 1:1.1-1.3.

[0015] Preferably, the mass ratio of the intermediate 1, 4-amino-3-fluorobenzenethiol, and benzoin dimethyl ether photoinitiator in (2) is 1.2-1.3:1:0.02-0.03.

[0016] Preferably, the mass ratio of intermediate 2, polyethylene glycol, epichlorohydrin, boron trifluoride etherate catalyst and sodium hydroxide in (3) is 0.8-1.2:1:2.8-3.5:0.04-0.06:0.05-0.07.

[0017] Preferably, the preparation method of the high temperature resistant fluoroelastomer processing aid for the slurry polyethylene process is: adding graphene oxide modified epoxy resin, fluorine-modified epoxy resin, and tetrafluoroethylene-vinylidene fluoride copolymer into a twin-screw extruder, the extrusion temperature is 170-180°C, the extrusion speed is 50-60min, the extrudate is crushed, extracted with acetone for 6-9h, filtered and dried to obtain the high temperature resistant fluoroelastomer processing aid for the slurry polyethylene process.

[0018] (III) Beneficial technical effects

[0019] The invention provides a high temperature resistant fluoroelastomer processing aid for a slurry polyethylene process by adding graphene oxide modified epoxy resin, fluorine-containing modified epoxy resin and tetrafluoroethylene-vinylidene fluoride copolymer into a twin-screw extruder, extruding, crushing the extrudate, extracting with acetone, filtering and drying.

[0020] Graphene oxide modified epoxy resin and fluorine-modified epoxy resin both have epoxy resin structure, so they have good compatibility, thereby improving the dispersibility in the high temperature resistant fluoroelastomer processing aid used in the slurry polyethylene process. The epoxy resin has good temperature resistance, and the graphene oxide has a good lubricating effect, so that the orifice of the die head will not be blocked. The large amount of fluoride contained in it through grafting can also reduce the friction between resins when used in polyethylene, delay shark skin melt fracture, make its surface smoother, and improve the processing performance and material flow rate. Among them, the graphene oxide itself has a good flame retardant effect and the sulfur element in the additive has a synergistic flame retardant effect. DETAILED DESCRIPTION

[0021] Example 1

[0022] (1) adding p-hydroxybenzaldehyde and o-aminotrifluorotoluene to N,N-dimethylformamide solvent, wherein the mass ratio of p-hydroxybenzaldehyde to o-aminotrifluorotoluene is 1:1.1, reacting at 75° C. for 8 h, and then distilling under reduced pressure, filtering and drying to obtain intermediate 1;

[0023] (2) adding intermediate 1 and 4-amino-3-fluorobenzenethiol to N,N-dimethylformamide solvent, stirring evenly, and then adding benzoin dimethyl ether photoinitiator thereto, wherein the mass ratio of intermediate 1, 4-amino-3-fluorobenzenethiol, and benzoin dimethyl ether photoinitiator is 1.2:1:0.02, irradiating with 365 nm ultraviolet light at 40° C. for 2 h, centrifuging, washing with distilled water, and drying to obtain intermediate 2;

[0024] (3) Add intermediate 2, polyethylene glycol, and epichlorohydrin to tetrahydrofuran solvent, stir and dissolve, then continue to add boron trifluoride etherate catalyst, react at 20° C. for 2 hours, and then continue to add sodium hydroxide to carry out a ring-closing reaction, wherein the mass ratio of intermediate 2, polyethylene glycol, epichlorohydrin, boron trifluoride etherate catalyst, and sodium hydroxide is 0.8:1:2.8:0.04:0.05, heat to 60° C. to react for 3 hours, centrifuge after completion, wash twice with n-hexane, and obtain a fluorine-modified epoxy resin;

[0025] (4) adding a water-based epoxy resin and an ethylenediamine curing agent into a reactor, stirring at high speed, and then adding graphene oxide thereto, wherein the mass ratio of the water-based epoxy resin, the ethylenediamine curing agent, and the graphene oxide is 1:0.02:1.1, and ultrasonically treating for 40 minutes to obtain a graphene oxide-modified epoxy resin;

[0026] (5) 4 parts by weight of graphene oxide modified epoxy resin, 10 parts by weight of fluorine-modified epoxy resin, and 40 parts by weight of tetrafluoroethylene-vinylidene fluoride copolymer are added into a twin-screw extruder at an extrusion temperature of 170°C and an extrusion speed of 50 min. The extrudate is crushed, extracted with acetone for 6 h, filtered, and dried to obtain a high-temperature resistant fluoroelastomer processing aid for a slurry polyethylene process.

[0027] Example 2

[0028] (1) adding p-hydroxybenzaldehyde and o-aminotrifluorotoluene to N,N-dimethylformamide solvent, wherein the mass ratio of p-hydroxybenzaldehyde to o-aminotrifluorotoluene is 1:1.3, reacting at 90° C. for 12 h, and then distilling under reduced pressure, filtering and drying to obtain intermediate 1;

[0029] (2) adding intermediate 1 and 4-amino-3-fluorobenzenethiol to N,N-dimethylformamide solvent, stirring evenly, and then adding benzoin dimethyl ether photoinitiator thereto, wherein the mass ratio of intermediate 1, 4-amino-3-fluorobenzenethiol, and benzoin dimethyl ether photoinitiator is 1.3:1:0.03, irradiating with 365 nm ultraviolet light at 50° C. for 4 h, centrifuging, washing with distilled water, and drying to obtain intermediate 2;

[0030] (3) Add intermediate 2, polyethylene glycol, and epichlorohydrin to tetrahydrofuran solvent, stir and dissolve, then continue to add boron trifluoride etherate catalyst, react at 25° C. for 4 hours, and then continue to add sodium hydroxide to carry out a ring-closing reaction, wherein the mass ratio of intermediate 2, polyethylene glycol, epichlorohydrin, boron trifluoride etherate catalyst, and sodium hydroxide is 1.2:1:3.5:0.06:0.07, heat to 70° C. to react for 4 hours, centrifuge after completion, wash 3 times with n-hexane, and obtain a fluorine-modified epoxy resin;

[0031] (4) adding a water-based epoxy resin and an ethylenediamine curing agent into a reactor, stirring at high speed, and then adding graphene oxide thereto, wherein the mass ratio of the water-based epoxy resin, the ethylenediamine curing agent, and the graphene oxide is 1:0.04:1.3, and ultrasonically treating for 70 minutes to obtain a graphene oxide-modified epoxy resin;

[0032] (5) 8 parts by weight of graphene oxide modified epoxy resin, 25 parts by weight of fluorine-modified epoxy resin, and 60 parts by weight of tetrafluoroethylene-vinylidene fluoride copolymer are added into a twin-screw extruder, the extrusion temperature is 180°C, the extrusion speed is 60 min, the extrudate is crushed, extracted with acetone for 9 h, filtered, and dried to obtain a high temperature resistant fluoroelastomer processing aid for slurry polyethylene process.

[0033] Example 3

[0034] (1) adding p-hydroxybenzaldehyde and o-aminotrifluorotoluene to N,N-dimethylformamide solvent, wherein the mass ratio of p-hydroxybenzaldehyde to o-aminotrifluorotoluene is 1:1.2, reacting at 82.5° C. for 10 h, and then distilling under reduced pressure, filtering and drying to obtain intermediate 1;

[0035] (2) adding intermediate 1 and 4-amino-3-fluorobenzenethiol to N,N-dimethylformamide solvent, stirring evenly, and then adding benzoin dimethyl ether photoinitiator thereto, wherein the mass ratio of intermediate 1, 4-amino-3-fluorobenzenethiol, and benzoin dimethyl ether photoinitiator is 1.25:1:0.025, irradiating with 365 nm ultraviolet light at 45° C. for 3 h, centrifuging, washing with distilled water, and drying to obtain intermediate 2;

[0036] (3) Add intermediate 2, polyethylene glycol, and epichlorohydrin to tetrahydrofuran solvent, stir and dissolve, then continue to add boron trifluoride etherate catalyst, react at 22.5° C. for 3 hours, and then continue to add sodium hydroxide to carry out a ring-closing reaction, wherein the mass ratio of intermediate 2, polyethylene glycol, epichlorohydrin, boron trifluoride etherate catalyst, and sodium hydroxide is 1.0:1:3.15:0.05:0.06, heat to 65° C. and react for 3.5 hours, then centrifuge and wash with n-hexane 2.5 times to obtain a fluorine-modified epoxy resin;

[0037] (4) adding a water-based epoxy resin and an ethylenediamine curing agent into a reactor, stirring at high speed, and then adding graphene oxide thereto, wherein the mass ratio of the water-based epoxy resin, the ethylenediamine curing agent, and the graphene oxide is 1:0.03:1.2, and ultrasonically treating for 55 minutes to obtain a graphene oxide-modified epoxy resin;

[0038] (5) 6 parts by weight of graphene oxide modified epoxy resin, 17.5 parts by weight of fluorine-modified epoxy resin, and 50 parts by weight of tetrafluoroethylene-vinylidene fluoride copolymer are added into a twin-screw extruder at an extrusion temperature of 175° C. and an extrusion speed of 55 min. The extrudate is crushed, extracted with acetone for 7.5 h, filtered, and dried to obtain a high-temperature resistant fluoroelastomer processing aid for a slurry polyethylene process.

[0039] Example 4

[0040] (1) adding p-hydroxybenzaldehyde and o-aminotrifluorotoluene to N,N-dimethylformamide solvent, wherein the mass ratio of p-hydroxybenzaldehyde to o-aminotrifluorotoluene is 1:1.1, reacting at 75° C. for 8 h, and then distilling under reduced pressure, filtering and drying to obtain intermediate 1;

[0041] (2) adding intermediate 1 and 4-amino-3-fluorobenzenethiol to N,N-dimethylformamide solvent, stirring evenly, and then adding benzoin dimethyl ether photoinitiator thereto, wherein the mass ratio of intermediate 1, 4-amino-3-fluorobenzenethiol, and benzoin dimethyl ether photoinitiator is 1.2:1:0.02, irradiating with 365 nm ultraviolet light at 40° C. for 2 h, centrifuging, washing with distilled water, and drying to obtain intermediate 2;

[0042] (3) Add intermediate 2, polyethylene glycol, and epichlorohydrin to tetrahydrofuran solvent, stir and dissolve, then continue to add boron trifluoride etherate catalyst, react at 25° C. for 4 hours, and then continue to add sodium hydroxide to carry out a ring-closing reaction, wherein the mass ratio of intermediate 2, polyethylene glycol, epichlorohydrin, boron trifluoride etherate catalyst, and sodium hydroxide is 1.2:1:3.5:0.06:0.07, heat to 70° C. to react for 4 hours, centrifuge after completion, wash 3 times with n-hexane, and obtain a fluorine-modified epoxy resin;

[0043] (4) adding a water-based epoxy resin and an ethylenediamine curing agent into a reactor, stirring at high speed, and then adding graphene oxide thereto, wherein the mass ratio of the water-based epoxy resin, the ethylenediamine curing agent, and the graphene oxide is 1:0.04:1.3, and ultrasonically treating for 70 minutes to obtain a graphene oxide-modified epoxy resin;

[0044] (5) 6 parts by weight of graphene oxide modified epoxy resin, 17.5 parts by weight of fluorine-modified epoxy resin, and 50 parts by weight of tetrafluoroethylene-vinylidene fluoride copolymer are added into a twin-screw extruder at an extrusion temperature of 175° C. and an extrusion speed of 55 min. The extrudate is crushed, extracted with acetone for 7.5 h, filtered, and dried to obtain a high-temperature resistant fluoroelastomer processing aid for a slurry polyethylene process.

[0045] Example 5

[0046] (1) adding p-hydroxybenzaldehyde and o-aminotrifluorotoluene to N,N-dimethylformamide solvent, wherein the mass ratio of p-hydroxybenzaldehyde to o-aminotrifluorotoluene is 1:1.3, reacting at 90° C. for 12 h, and then distilling under reduced pressure, filtering and drying to obtain intermediate 1;

[0047] (2) adding intermediate 1 and 4-amino-3-fluorobenzenethiol to N,N-dimethylformamide solvent, stirring evenly, and then adding benzoin dimethyl ether photoinitiator thereto, wherein the mass ratio of intermediate 1, 4-amino-3-fluorobenzenethiol, and benzoin dimethyl ether photoinitiator is 1.3:1:0.03, irradiating with 365 nm ultraviolet light at 50° C. for 4 h, centrifuging, washing with distilled water, and drying to obtain intermediate 2;

[0048] (3) Add intermediate 2, polyethylene glycol, and epichlorohydrin to tetrahydrofuran solvent, stir and dissolve, then continue to add boron trifluoride etherate catalyst, react at 22.5° C. for 3 hours, and then continue to add sodium hydroxide to carry out a ring-closing reaction, wherein the mass ratio of intermediate 2, polyethylene glycol, epichlorohydrin, boron trifluoride etherate catalyst, and sodium hydroxide is 1.0:1:3.15:0.05:0.06, heat to 65° C. and react for 3.5 hours, then centrifuge and wash with n-hexane 2.5 times to obtain a fluorine-modified epoxy resin;

[0049] (4) adding a water-based epoxy resin and an ethylenediamine curing agent into a reactor, stirring at high speed, and then adding graphene oxide thereto, wherein the mass ratio of the water-based epoxy resin, the ethylenediamine curing agent, and the graphene oxide is 1:0.03:1.2, and ultrasonically treating for 55 minutes to obtain a graphene oxide-modified epoxy resin;

[0050] (5) 4 parts by weight of graphene oxide modified epoxy resin, 10 parts by weight of fluorine-modified epoxy resin, and 40 parts by weight of tetrafluoroethylene-vinylidene fluoride copolymer are added into a twin-screw extruder at an extrusion temperature of 170°C and an extrusion speed of 50 min. The extrudate is crushed, extracted with acetone for 6 h, filtered, and dried to obtain a high-temperature resistant fluoroelastomer processing aid for a slurry polyethylene process.

[0051] Comparative Example 1

[0052] Compared with Example 5, this comparative example does not add graphene oxide-modified epoxy resin.

[0053] Comparative Example 2

[0054] Compared with Example 5, this comparative example does not add fluorine-modified epoxy resin.

[0055] The fluoroelastomer processing aids of Examples 1-5 and Comparative Examples 1-2 were mixed with polyethylene and extrusion tests were carried out on a Haake rheometer. The test results of extrusion time, extrusion torque, die pressure, and melt fracture are shown in Table 1.

[0056] Table 1: Performance test of fluoroelastomer processing aids.

[0057]

[0058]

[0059] As can be seen from Table 1, compared with the fluoroelastomer processing aids prepared in Comparative Examples 1-2, the melt fracture elimination time of the fluoroelastomer processing aids prepared in Examples 1-5 of the present invention is shortened, and the die pressure and torque are greatly reduced, indicating that they have a better flow rate, improved melt fracture, and improved processing performance.

[0060] The oxygen index meter is used to test the limiting oxygen index of the material, and the horizontal and vertical combustion instrument is used to test the combustion grade of the mixed material of fluoroelastomer processing aid and polyethylene.

[0061] Table 2: Flame retardancy test.

[0062] project Limiting oxygen index (%) Combustion level Example 1 28 V-0 Example 2 35 V-0 Example 3 33 V-0 Example 4 29 V-0 Example 5 30 V-0 Comparative Example 1 24 V-1 Comparative Example 2 21 V-1

[0063] It can be seen from Table 2 that the fluoroelastomer processing aids prepared in Examples 1-5 of the present invention, compared with those prepared in Comparative Examples 1-2, are applied to polyethylene to give it a better flame retardant effect.

[0064] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A high temperature resistant fluoroelastomer processing aid for slurry polyethylene process, characterized in that: The invention comprises the following components by weight: 4-8 parts by weight of graphene oxide modified epoxy resin, 10-25 parts by weight of fluorine-containing modified epoxy resin, and 40-60 parts by weight of tetrafluoroethylene-vinylidene fluoride copolymer; Characterized in that, the preparation method of the graphene oxide modified epoxy resin is: S1. Adding a water-based epoxy resin and an ethylenediamine curing agent into a reactor, stirring at high speed, adding graphene oxide thereto, and ultrasonically treating for 40-70 min to obtain a graphene oxide-modified epoxy resin; The mass ratio of the waterborne epoxy resin, ethylenediamine curing agent and graphene oxide is 1:0.02-0.04:1.1-1.3; The preparation method of the fluorine-modified epoxy resin is: (1) adding p-hydroxybenzaldehyde and o-aminotrifluorotoluene to N,N-dimethylformamide solvent, reacting at 75-90° C. for 8-12 hours, and then distilling under reduced pressure, filtering and drying to obtain intermediate 1; (2) adding intermediate 1 and 4-amino-3-fluorobenzenethiol to N,N-dimethylformamide solvent, stirring evenly, then adding benzoin dimethyl ether photoinitiator thereto, irradiating with 365 nm ultraviolet light at 40-50° C. for 2-4 h, centrifuging, washing with distilled water, and drying to obtain intermediate 2; (3) Add intermediate 2, polyethylene glycol, and epichlorohydrin to tetrahydrofuran solvent, stir to dissolve, then continue to add boron trifluoride ether catalyst, react at 20-25° C. for 2-4 hours, then continue to add sodium hydroxide to carry out ring-closing reaction, heat to 60-70° C. to react for 3-4 hours, centrifuge after completion, wash with n-hexane 2-3 times, and obtain fluorine-modified epoxy resin; The mass ratio of p-hydroxybenzaldehyde to o-aminotrifluorotoluene in (1) is 1:1.1-1.3; The mass ratio of the intermediate 1, 4-amino-3-fluorobenzenethiol, and benzoin dimethyl ether photoinitiator in (2) is 1.2-1.3:1:0.02-0.03; The mass ratio of the intermediate 2, polyethylene glycol, epichlorohydrin, boron trifluoride etherate catalyst and sodium hydroxide in (3) is 0.8-1.2:1:2.8-3.5:0.04-0.06:0.05-0.

07.

2. A method for preparing a high temperature resistant fluoroelastomer processing aid for slurry polyethylene process as claimed in claim 1, characterized in that: The preparation method of the high temperature resistant fluoroelastomer processing aid for slurry polyethylene process is as follows: graphene oxide modified epoxy resin, fluorine-containing modified epoxy resin, and tetrafluoroethylene-vinylidene fluoride copolymer are added into a twin-screw extruder, the extrusion temperature is 170-180°C, the extrusion speed is 50-60min, the extrudate is crushed, acetone is extracted for 6-9h, filtered, and dried to obtain the high temperature resistant fluoroelastomer processing aid for slurry polyethylene process.

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