Corrosion-resistant, aging-resistant and flame-retardant ETFE film and preparation process thereof

Abstract

The invention relates to the technical field of high polymer materials, in particular to a corrosion-resistant, aging-resistant and flame-retardant ETFE film and a preparation process thereof. The preparation process comprises the following steps: preparing the ETFE polymer; preparing modified polytetrafluoroethylene microsphere powder; preparing a dopamine modified polytetrafluoroethylene emulsion; and preparing the corrosion-resistant, aging-resistant and flame-retardant ETFE film. According to the preparation method disclosed by the invention, the polytetrafluoroethylene is modified by utilizing dopamine, after the emulsion is prepared, the surface of the ETFE film is covered with a layer of coating, the dopamine can spontaneously polymerize into polydopamine in a natural environment, the polydopamine has relatively good adhesion and can be firmly combined with the ETFE film, and the polytetrafluoroethylene and the ETFE film have similar structures and chemical characteristics, so that the preparation method has the advantages that the preparation method is simple, the cost is low, and the application prospect is wide. The ETFE film does not fall off after being tightly bonded for a long time, but the two films are gradually fused, so that the aging resistance of the ETFE film is improved.

Description

Technical Field

[0001] The invention relates to the technical field of polymer materials, and in particular to a corrosion-resistant, aging-resistant and flame-retardant ETFE film and a preparation process thereof. Background Art

[0002] ETFE is a polymer material formed by copolymerization of ethylene (ETHYLENE) and tetrafluoroethylene (TETRAFLUOROETHYLENE). This copolymerization process requires precise catalyst technology and reaction condition control to ensure that the product has the expected performance balance, including excellent chemical stability and mechanical properties. ETFE film is widely used in modern architectural design, and is used in building ceilings, greenhouses, and transparent enclosures. It has the advantages of providing natural lighting while reducing structural burdens. Its light weight and high temperature resistance also have special applications in spacecraft components.

[0003] In the prior art, ETFE membrane is generally prepared by directly polymerizing ethylene and tetrafluoroethylene gas, and the obtained polymer is extruded into a film. The process is mature and simple. However, the thermal expansion coefficient of ETFE polymer is higher than that of other building materials. Therefore, regular maintenance is required to ensure long-term performance. Its aging resistance is average. Since the steps for preparing ETFE polymer in the prior art are simple and mature, other treatments of the ETFE membrane are not considered, but regular maintenance is used to ensure the long-term use of the ETFE membrane. Therefore, the present invention provides a corrosion-resistant, aging-resistant and flame-retardant ETFE membrane and a preparation process thereof. By treating the ETFE membrane, the aging resistance of the ETFE membrane is improved and the maintenance times are reduced. Summary of the invention

[0004] In view of the deficiencies in the prior art, the object of the present invention is to provide a corrosion-resistant, aging-resistant and flame-retardant ETFE film and a preparation process thereof.

[0005] A preparation process of a corrosion-resistant, aging-resistant and flame-retardant ETFE film comprises the following steps:

[0006] S1: Preparation of ETFE polymer

[0007] A silane coupling agent, sodium dihydrogen phosphate and ethylene diether are mixed and added into a reactor, an initiator is added, isopentyl bromide is introduced, and a mixed gas of ethylene and tetrafluoroethylene is introduced into the reactor for reaction to obtain an ETFE polymer, and the ETFE polymer is extruded into a film through an extruder to obtain an ETFE film;

[0008] S2: Preparation of modified polytetrafluoroethylene microsphere powder

[0009] First, deionized water is added to a reaction bottle, polytetrafluoroethylene and butyl acrylate are weighed in sequence and added to the reaction bottle, the reaction bottle is placed in a constant temperature water bath for heating and stirring, an ammonium persulfate solution is added to the reaction bottle, after the reaction, the product is collected by filtration and centrifugation to obtain modified polytetrafluoroethylene microspheres, the modified polytetrafluoroethylene microspheres obtained by centrifugation are dried, ground and sieved to obtain modified polytetrafluoroethylene microsphere powder, and the powder is stored in a dry environment for use;

[0010] S3: Preparation of dopamine-modified polytetrafluoroethylene emulsion

[0011] First, deionized water is added to a reaction bottle, tris(hydroxymethyl)aminomethane) is weighed into the reaction bottle, and hydrochloric acid is added to adjust the pH to obtain an acidic solution, modified polytetrafluoroethylene microsphere powder is weighed and added to the acidic solution, ultrasonically dispersed to obtain a modified polytetrafluoroethylene microsphere dispersion, dopamine hydrochloride is added to the modified polytetrafluoroethylene microsphere dispersion, and magnetic stirring is performed to obtain a dopamine-modified polytetrafluoroethylene emulsion;

[0012] S4: Preparation of corrosion-resistant, aging-resistant and flame-retardant ETFE film

[0013] The ETFE film was fixed on a dipping device and immersed in a dopamine-modified polytetrafluoroethylene emulsion, followed by drying, heating, annealing and cooling to obtain a modified ETFE film. The modified ETFE film was electron irradiated for 5 minutes at a irradiation dose of 10 Mrad to obtain a corrosion-resistant, aging-resistant and flame-retardant ETFE film.

[0014] Further, step S1 prepares the ETFE polymer, comprising the following steps:

[0015] S1.1: 10-12 parts by mass of silane coupling agent, 8-10 parts by mass of sodium dihydrogen phosphate and 8 parts by mass of ethylene diether were mixed and added to a reaction kettle, and then an initiator was added, and 5 parts by volume of isopentyl bromide were introduced, and the mixture was stirred at a speed of 200-220 r / min for 10-15 min, and the temperature was raised to 40-50°C;

[0016] S1.2: Add a mixed gas of ethylene and tetrafluoroethylene into the reactor until the pressure in the reactor reaches 4 MPa, and react for 4-4.5 hours. During the reaction, keep adding the mixed gas of ethylene and tetrafluoroethylene to keep the pressure in the reactor at 4 MPa to obtain ETFE polymer;

[0017] S1.3: Extruding the ETFE polymer into a film through an extruder to obtain an ETFE film.

[0018] Furthermore, step S2 of preparing modified polytetrafluoroethylene microsphere powder comprises the following steps:

[0019] S2.1: First, add 100 parts by mass of deionized water into a reaction bottle, and then weigh 25-30 parts by mass of polytetrafluoroethylene and 10-12 parts by mass of butyl acrylate and add them into the reaction bottle;

[0020] S2.2: Place the reaction bottle in a constant temperature water bath for heating and stirring. When the temperature of the reaction system rises to 75°C, add 5 parts by weight of ammonium persulfate solution into the reaction bottle;

[0021] S2.3: maintaining the temperature of the reaction system at 75°C and the stirring speed at 350-400 r / min, the reaction continued for 7-7.5 hours, and the product was collected by filtration and centrifugation to obtain modified polytetrafluoroethylene microspheres;

[0022] S2.4: Dry the modified polytetrafluoroethylene microspheres obtained by centrifugation, grind them and pass them through an 80-mesh sieve to obtain modified polytetrafluoroethylene microsphere powder, and store it in a dry environment for future use.

[0023] Furthermore, step S3 prepares the dopamine-modified polytetrafluoroethylene emulsion, comprising the following steps:

[0024] S3.1: First, add 50 parts by weight of deionized water into a reaction bottle, weigh 0.06-0.08 parts by weight of tris(hydroxymethyl)aminomethane into the reaction bottle, and add hydrochloric acid to adjust the pH to 8.5 to obtain an acidic solution;

[0025] S3.2: Weigh the modified polytetrafluoroethylene microsphere powder and add it to the acid solution, and disperse it by ultrasonic for 30-35 minutes to obtain a modified polytetrafluoroethylene microsphere dispersion;

[0026] S3.3: Finally, 20-40 parts by weight of dopamine hydrochloride is added to the modified polytetrafluoroethylene microsphere dispersion, and the reaction is continued for 20-24 hours at room temperature with a magnetic stirring speed of 250 r / min to obtain a dopamine-modified polytetrafluoroethylene emulsion.

[0027] Further, step S4 prepares the corrosion-resistant, aging-resistant and flame-retardant ETFE film, comprising the following steps:

[0028] S4.1: After fixing the ETFE membrane on the dipping device, immerse it vertically in the dopamine-modified polytetrafluoroethylene emulsion at a speed of 5 mm / min, and then vertically pull it up at a speed of 5 mm / min after the ETFE membrane is completely immersed for 20 seconds;

[0029] S4.2: then drying at 120°C for 10-12min, heating at 300-350°C for 4-5min, then annealing at 372°C for 4min, and finally naturally cooling at room temperature of 25°C to obtain a modified ETFE film;

[0030] S4.3: The modified ETFE film is subjected to electron irradiation for 5 minutes at an irradiation dose of 10 Mrad to obtain a corrosion-resistant, aging-resistant and flame-retardant ETFE film.

[0031] Furthermore, in step S1.1, the initiator is benzoyl peroxide, and the amount of the initiator added is 1-5% of the total mass of the system after the silane coupling agent and sodium dihydrogen phosphate are added.

[0032] Furthermore, the molar mass ratio of ethylene to tetrafluoroethylene in the mixed gas in step S1.2 is 7:10.

[0033] Furthermore, the ammonium persulfate solution in step S2.2 is prepared by dissolving 0.15-0.2 parts by mass of ammonium persulfate in 5 parts by mass of deionized water and stirring the mixture uniformly.

[0034] Furthermore, in step S3.2, the mass ratio of the modified polytetrafluoroethylene microsphere powder to the acidic solution is (0.1-0.5):50.

[0035] A corrosion-resistant, aging-resistant and flame-retardant ETFE film is prepared by any of the above-mentioned preparation processes for the corrosion-resistant, aging-resistant and flame-retardant ETFE films.

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

[0037] 1. The present invention utilizes dopamine to modify polytetrafluoroethylene, and after preparing into an emulsion, a coating is covered on the surface of the ETFE film. After dopamine and polytetrafluoroethylene are prepared into an emulsion, a micron-sized cluster structure can be formed, so that the coating made of the emulsion has both good adhesion and compatibility with the ETFE film. Dopamine can spontaneously polymerize into polydopamine under natural conditions. Polydopamine has good adhesion and can make the dopamine-modified polytetrafluoroethylene emulsion and the ETFE film firmly combined during coating. Moreover, after being used for a period of time, the viscosity is reduced due to a certain degree of decomposition of the dopamine-modified polytetrafluoroethylene molecules. At this time, the polytetrafluoroethylene and the ETFE film have similar structures and chemical characteristics. After the dopamine-modified polytetrafluoroethylene molecules and the ETFE film are tightly adhered for a long time, the surfaces of the two are fused, so that when the viscosity is reduced, it can still be ensured that the coating formed by the dopamine-modified polytetrafluoroethylene will not fall off, thereby increasing the aging resistance of the ETFE film.

[0038] 2. The present invention utilizes ethylene diether and isopentyl bromide to adjust the molecular weight of the ETFE polymer when preparing the ETFE polymer. The halogen atom of isopentyl bromide has high reactivity and reacts with the growing polymer chain in the free radical polymerization process, thereby transferring the growing chain and generating a new free radical. In this process, ethylene diether can select the free radical of the isopentyl bromide reaction and improve the selectivity of the free radical, thereby achieving the effect of effectively controlling the growth of the polymer chain and controlling the molecular weight of the polymer chain. Thus, the chain terminal function is selected by regulating the molecular weight and molecular weight distribution of the polymer, thereby achieving the purpose of improving the physical strength of the ETFE film, making the ETFE film less susceptible to corrosion and aging.

[0039] 3. The present invention prepares polytetrafluoroethylene into microspheres, grinds the microspheres into powders, and then combines the microspheres with dopamine. The polytetrafluoroethylene itself is stable and has a flame retardant function. The microspheres also have extremely low surface energy. Combined with the excellent adhesion of polydopamine, the microspheres are not easily decomposed by high temperatures, thereby improving the flame retardant properties of the ETFE film. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The accompanying drawings, which are incorporated herein and constitute a part of the specification, illustrate embodiments of the present disclosure and, together with the description, further serve to explain the principles of the present disclosure and to enable those skilled in the relevant art to make and use the present disclosure.

[0041] Figure 1 This is a process flow chart for preparing a corrosion-resistant, aging-resistant and flame-retardant ETFE film used in an embodiment of the present invention. DETAILED DESCRIPTION

[0042] The following is a detailed description of a corrosion-resistant, aging-resistant, flame-retardant ETFE film and its preparation process provided by the present invention in conjunction with the accompanying drawings and specific embodiments. At the same time, it is explained here that in order to make the embodiments more detailed, the following embodiments are the best and preferred embodiments, and those skilled in the art may also adopt other alternatives to implement some known technologies; and the accompanying drawings are only for more specific description of the embodiments, and are not intended to specifically limit the present invention.

[0043] Embodiment 1:

[0044] A preparation process of a corrosion-resistant, aging-resistant and flame-retardant ETFE film, such as Figure 1 As shown, the following steps are included:

[0045] S1: Preparation of ETFE polymer

[0046] S1.1: 10 parts by mass of silane coupling agent, 8 parts by mass of sodium dihydrogen phosphate and 8 parts by mass of ethylene diether were mixed and added to a reactor, and then benzoyl peroxide as an initiator was added, the amount of initiator added was 5% of the total mass of the system after the addition of the silane coupling agent and sodium dihydrogen phosphate, and 5 parts by volume of isopentyl bromide was introduced, stirred at a speed of 220 r / min for 15 min, and the temperature was raised to 40°C;

[0047] S1.2: Add a mixed gas of ethylene and tetrafluoroethylene into the reactor, the molar mass ratio of ethylene to tetrafluoroethylene is 7:10, until the pressure in the reactor reaches 4 MPa, and react for 4 hours. During the reaction, keep adding the mixed gas of ethylene and tetrafluoroethylene to keep the pressure in the reactor at 4 MPa to obtain ETFE polymer;

[0048] S1.3: Extruding the ETFE polymer into a film through an extruder to obtain an ETFE film.

[0049] S2: Preparation of modified polytetrafluoroethylene microsphere powder

[0050] S2.1: First, add 100 parts by mass of deionized water into a reaction bottle, and then weigh 25 parts by mass of polytetrafluoroethylene and 10 parts by mass of butyl acrylate and add them into the reaction bottle;

[0051] S2.2: placing the reaction bottle in a constant temperature water bath for heating and stirring, when the temperature of the reaction system rises to 75°C, adding 5 parts by weight of ammonium persulfate solution into the reaction bottle, wherein the ammonium persulfate solution is prepared by dissolving 0.15 parts by weight of ammonium persulfate in 5 parts by weight of deionized water and stirring uniformly;

[0052] S2.3: The temperature of the reaction system is maintained at 75°C and the stirring speed is 350 r / min. After the reaction is continued for 7 hours, the product is collected by filtration and centrifugation to obtain modified polytetrafluoroethylene microspheres;

[0053] S2.4: Dry the modified polytetrafluoroethylene microspheres obtained by centrifugation, grind them and pass them through an 80-mesh sieve to obtain modified polytetrafluoroethylene microsphere powder, and store it in a dry environment for future use.

[0054] S3: Preparation of dopamine-modified polytetrafluoroethylene emulsion

[0055] S3.1: First, add 50 parts by mass of deionized water into a reaction bottle, weigh 0.06 parts by mass of tris(hydroxymethyl)aminomethane into the reaction bottle, and add hydrochloric acid to adjust the pH to 8.5 to obtain an acidic solution;

[0056] S3.2: Weigh the modified polytetrafluoroethylene microsphere powder and add it to the acid solution, the mass ratio of the modified polytetrafluoroethylene microsphere powder to the acid solution is 0.5:50, and ultrasonically disperse for 30 minutes to obtain a modified polytetrafluoroethylene microsphere dispersion;

[0057] S3.3: Finally, 20 parts by weight of dopamine hydrochloride was added to the modified polytetrafluoroethylene microsphere dispersion, and the reaction was continued for 20 hours at room temperature with a magnetic stirring speed of 250 r / min to obtain a dopamine-modified polytetrafluoroethylene emulsion.

[0058] S4: Preparation of corrosion-resistant, aging-resistant and flame-retardant ETFE film

[0059] S4.1: After fixing the ETFE membrane on the dipping device, immerse it vertically in the dopamine-modified polytetrafluoroethylene emulsion at a speed of 5 mm / min, and then vertically pull it up at a speed of 5 mm / min after the ETFE membrane is completely immersed for 20 seconds;

[0060] S4.2: then drying at 120°C for 10 min, heating at 300°C for 4 min, then annealing at 372°C for 4 min, and finally naturally cooling at room temperature of 25°C to obtain a modified ETFE film;

[0061] S4.3: The modified ETFE film is subjected to electron irradiation for 5 minutes at an irradiation dose of 10 Mrad to obtain a corrosion-resistant, aging-resistant and flame-retardant ETFE film.

[0062] Embodiment 2:

[0063] A preparation process of a corrosion-resistant, aging-resistant and flame-retardant ETFE film, such as Figure 1 As shown, the following steps are included:

[0064] S1: Preparation of ETFE polymer

[0065] S1.1: 12 parts by mass of silane coupling agent, 10 parts by mass of sodium dihydrogen phosphate and 8 parts by mass of ethylene diether were mixed and added to a reactor, and then benzoyl peroxide as an initiator was added, the amount of initiator added was 1% of the total mass of the system after the addition of the silane coupling agent and sodium dihydrogen phosphate, and 5 parts by volume of isopentyl bromide was introduced, stirred at a speed of 220 r / min for 15 min, and the temperature was raised to 40°C;

[0066] S1.2: Add a mixed gas of ethylene and tetrafluoroethylene into the reactor, the molar mass ratio of ethylene to tetrafluoroethylene is 7:10, until the pressure in the reactor reaches 4 MPa, and react for 4 hours. During the reaction, keep adding the mixed gas of ethylene and tetrafluoroethylene to keep the pressure in the reactor at 4 MPa to obtain ETFE polymer;

[0067] S1.3: Extruding the ETFE polymer into a film through an extruder to obtain an ETFE film.

[0068] S2: Preparation of modified polytetrafluoroethylene microsphere powder

[0069] S2.1: First, add 100 parts by mass of deionized water into a reaction bottle, and then weigh 30 parts by mass of polytetrafluoroethylene and 12 parts by mass of butyl acrylate and add them into the reaction bottle;

[0070] S2.2: placing the reaction bottle in a constant temperature water bath for heating and stirring, when the temperature of the reaction system rises to 75°C, adding 5 parts by weight of ammonium persulfate solution into the reaction bottle, wherein the ammonium persulfate solution is prepared by dissolving 0.15 parts by weight of ammonium persulfate in 5 parts by weight of deionized water and stirring uniformly;

[0071] S2.3: The temperature of the reaction system is maintained at 75°C and the stirring speed is 350 r / min. After the reaction is continued for 7 hours, the product is collected by filtration and centrifugation to obtain modified polytetrafluoroethylene microspheres;

[0072] S2.4: Dry the modified polytetrafluoroethylene microspheres obtained by centrifugation, grind them and pass them through an 80-mesh sieve to obtain modified polytetrafluoroethylene microsphere powder, and store it in a dry environment for future use.

[0073] S3: Preparation of dopamine-modified polytetrafluoroethylene emulsion

[0074] S3.1: First, add 50 parts by mass of deionized water into a reaction bottle, weigh 0.08 parts by mass of tris(hydroxymethyl)aminomethane into the reaction bottle, and add hydrochloric acid to adjust the pH to 8.5 to obtain an acidic solution;

[0075] S3.2: Weigh the modified polytetrafluoroethylene microsphere powder and add it to the acid solution, the mass ratio of the modified polytetrafluoroethylene microsphere powder to the acid solution is 0.1:50, and ultrasonically disperse for 30 minutes to obtain a modified polytetrafluoroethylene microsphere dispersion;

[0076] S3.3: Finally, 40 parts by weight of dopamine hydrochloride was added to the modified polytetrafluoroethylene microsphere dispersion, and the reaction was continued for 20 hours at room temperature with a magnetic stirring speed of 250 r / min to obtain a dopamine-modified polytetrafluoroethylene emulsion.

[0077] S4: Preparation of corrosion-resistant, aging-resistant and flame-retardant ETFE film

[0078] S4.1: After fixing the ETFE membrane on the dipping device, immerse it vertically in the dopamine-modified polytetrafluoroethylene emulsion at a speed of 5 mm / min, and then vertically pull it up at a speed of 5 mm / min after the ETFE membrane is completely immersed for 20 seconds;

[0079] S4.2: then drying at 120°C for 10 min, heating at 300°C for 4 min, then annealing at 372°C for 4 min, and finally naturally cooling at room temperature of 25°C to obtain a modified ETFE film;

[0080] S4.3: The modified ETFE film is subjected to electron irradiation for 5 minutes at an irradiation dose of 10 Mrad to obtain a corrosion-resistant, aging-resistant and flame-retardant ETFE film.

[0081] Embodiment 3:

[0082] A preparation process of a corrosion-resistant, aging-resistant and flame-retardant ETFE film, such as Figure 1 As shown, the following steps are included:

[0083] S1: Preparation of ETFE polymer

[0084] S1.1: 10 parts by mass of silane coupling agent, 8 parts by mass of sodium dihydrogen phosphate and 8 parts by mass of ethylene diether were mixed and added to a reactor, and then benzoyl peroxide as an initiator was added, the amount of initiator added was 5% of the total mass of the system after the addition of the silane coupling agent and sodium dihydrogen phosphate, and 5 parts by volume of isopentyl bromide was introduced, stirred at a speed of 200 r / min for 10 min, and the temperature was raised to 50°C;

[0085] S1.2: A mixed gas of ethylene and tetrafluoroethylene is introduced into the reactor, the molar mass ratio of ethylene to tetrafluoroethylene is 7:10, until the pressure in the reactor reaches 4 MPa, and the reaction is carried out for 4.5 hours. During the reaction, the mixed gas of ethylene and tetrafluoroethylene is added to keep the pressure in the reactor at 4 MPa, to obtain ETFE polymer;

[0086] S1.3: Extruding the ETFE polymer into a film through an extruder to obtain an ETFE film.

[0087] S2: Preparation of modified polytetrafluoroethylene microsphere powder

[0088] S2.1: First, add 100 parts by mass of deionized water into a reaction bottle, and then weigh 25 parts by mass of polytetrafluoroethylene and 10 parts by mass of butyl acrylate and add them into the reaction bottle;

[0089] S2.2: placing the reaction bottle in a constant temperature water bath for heating and stirring, when the temperature of the reaction system rises to 75°C, adding 5 parts by weight of ammonium persulfate solution into the reaction bottle, wherein the ammonium persulfate solution is prepared by dissolving 0.15 parts by weight of ammonium persulfate in 5 parts by weight of deionized water and stirring uniformly;

[0090] S2.3: The temperature of the reaction system was maintained at 75°C and the stirring speed was 400 r / min. After the reaction lasted for 7.5 hours, the product was collected by filtration and centrifugation to obtain modified polytetrafluoroethylene microspheres;

[0091] S2.4: Dry the modified polytetrafluoroethylene microspheres obtained by centrifugation, grind them and pass them through an 80-mesh sieve to obtain modified polytetrafluoroethylene microsphere powder, and store it in a dry environment for future use.

[0092] S3: Preparation of dopamine-modified polytetrafluoroethylene emulsion

[0093] S3.1: First, add 50 parts by mass of deionized water into a reaction bottle, weigh 0.06 parts by mass of tris(hydroxymethyl)aminomethane into the reaction bottle, and add hydrochloric acid to adjust the pH to 8.5 to obtain an acidic solution;

[0094] S3.2: Weigh the modified polytetrafluoroethylene microsphere powder and add it to the acidic solution, the mass ratio of the modified polytetrafluoroethylene microsphere powder to the acidic solution is 0.5:50, and ultrasonically disperse for 35 minutes to obtain a modified polytetrafluoroethylene microsphere dispersion;

[0095] S3.3: Finally, 20 parts by weight of dopamine hydrochloride was added to the modified polytetrafluoroethylene microsphere dispersion, and the reaction was continued for 24 hours at room temperature with a magnetic stirring speed of 250 r / min to obtain a dopamine-modified polytetrafluoroethylene emulsion.

[0096] S4: Preparation of corrosion-resistant, aging-resistant and flame-retardant ETFE film

[0097] S4.1: After fixing the ETFE membrane on the dipping device, immerse it vertically in the dopamine-modified polytetrafluoroethylene emulsion at a speed of 5 mm / min, and then vertically pull it up at a speed of 5 mm / min after the ETFE membrane is completely immersed for 20 seconds;

[0098] S4.2: then drying at 120°C for 12 min, heating at 350°C for 5 min, then annealing at 372°C for 4 min, and finally naturally cooling at room temperature of 25°C to obtain a modified ETFE film;

[0099] S4.3: The modified ETFE film is subjected to electron irradiation for 5 minutes at an irradiation dose of 10 Mrad to obtain a corrosion-resistant, aging-resistant and flame-retardant ETFE film.

[0100] Comparative Example 1:

[0101] Compared with Example 1, the difference of Comparative Example 1 is that, instead of using dopamine to modify polytetrafluoroethylene, aramid fiber is modified with dopamine, and the aramid fiber is used to prepare a dispersion liquid, and the dopamine-modified aramid fiber emulsion is prepared and coated on the ETFE film, specifically, "S3: preparing dopamine-modified aramid fiber emulsion

[0102] S3.1: First, add 50 parts by mass of deionized water into a reaction bottle, weigh 0.06 parts by mass of tris(hydroxymethyl)aminomethane into the reaction bottle, and add hydrochloric acid to adjust the pH to 8.5 to obtain an acidic solution;

[0103] S3.2: Weigh aramid fiber powder and add it to the acid solution, the mass ratio of aramid fiber powder to acid solution is 0.5:50, and ultrasonically disperse for 30 minutes to obtain a modified aramid fiber dispersion;

[0104] S3.3: Finally, 20 parts by weight of dopamine hydrochloride was added to the modified aramid fiber dispersion, and the reaction was continued for 20 hours at room temperature with a magnetic stirring speed of 250 r / min to obtain a dopamine-modified aramid fiber emulsion.

[0105] S4: Preparation of corrosion-resistant, aging-resistant and flame-retardant ETFE film

[0106] S4.1: After fixing the ETFE membrane on the dipping device, vertically immerse it into the dopamine-modified aramid fiber emulsion at a speed of 5 mm / min, and then vertically pull it up at a speed of 5 mm / min after the ETFE membrane is completely immersed for 20 seconds;

[0107] S4.2: then drying at 120°C for 10 min, heating at 300°C for 4 min, then annealing at 372°C for 4 min, and finally naturally cooling at room temperature of 25°C to obtain a modified ETFE film;

[0108] S4.3: The modified ETFE film is subjected to electron irradiation for 5 min at an irradiation dose of 10 Mrad to obtain a corrosion-resistant, aging-resistant and flame-retardant ETFE film. The experimental results are used to evaluate whether the aramid fiber and the ETFE film can be combined. The prepared corrosion-resistant, aging-resistant and flame-retardant ETFE film is recorded as Comparative Example 1.

[0109] Comparative Example 2:

[0110] Compared with Example 1, the difference of Comparative Example 2 is that step S2 is not performed to prepare modified polytetrafluoroethylene microsphere powder, but dopamine hydrochloride is directly mixed with polytetrafluoroethylene, specifically: "S3.1: first, 50 parts by mass of deionized water are added to a reaction bottle, 0.06 parts by mass of tris(hydroxymethyl)aminomethane are weighed into the reaction bottle, and hydrochloric acid is added to adjust the pH to 8.5 to obtain an acidic solution;

[0111] S3.2: Weigh polytetrafluoroethylene and add it to the acidic solution, the mass ratio of polytetrafluoroethylene to the acidic solution is 0.5:50, and ultrasonically disperse for 30 minutes to obtain a modified polytetrafluoroethylene microsphere dispersion;

[0112] S3.3: Finally, 20 parts by weight of dopamine hydrochloride was added to the modified polytetrafluoroethylene microsphere dispersion, and the reaction was continued for 20 hours at room temperature with a magnetic stirring speed of 250 r / min to obtain a dopamine-modified polytetrafluoroethylene emulsion. The prepared corrosion-resistant, aging-resistant and flame-retardant ETFE film was recorded as Comparative Example 2.

[0113] Comparative Example 3:

[0114] Compared with Example 1, the difference of Comparative Example 3 is that step S2 and step S3 are not performed, and the ETFE film is directly used for testing instead of using dopamine-modified polytetrafluoroethylene emulsion to form a coating on the surface of the ETFE film, specifically: "S1: Preparation of ETFE polymer

[0115] S1.1: 10 parts by mass of silane coupling agent, 8 parts by mass of sodium dihydrogen phosphate and 8 parts by mass of ethylene diether were mixed and added to a reactor, and then benzoyl peroxide as an initiator was added, the amount of initiator added was 5% of the total mass of the system after the addition of the silane coupling agent and sodium dihydrogen phosphate, and 5 parts by volume of isopentyl bromide was introduced, stirred at a speed of 220 r / min for 15 min, and the temperature was raised to 40°C;

[0116] S1.2: Add a mixed gas of ethylene and tetrafluoroethylene into the reactor, the molar mass ratio of ethylene to tetrafluoroethylene is 7:10, until the pressure in the reactor reaches 4 MPa, and react for 4 hours. During the reaction, keep adding the mixed gas of ethylene and tetrafluoroethylene to keep the pressure in the reactor at 4 MPa to obtain ETFE polymer;

[0117] S1.3: Extruding an ETFE polymer into a film through an extruder to obtain an ETFE film, and subjecting the ETFE film to electron irradiation for 5 min at an irradiation dose of 10 Mrad to obtain a corrosion-resistant, aging-resistant, and flame-retardant ETFE film. The prepared corrosion-resistant, aging-resistant, and flame-retardant ETFE film is recorded as Comparative Example 3.

[0118] Comparative Example 4:

[0119] Compared with Example 1, the difference of Comparative Example 4 is that in step S1, pentane is directly added instead of brominated isopentane, specifically: “S1.1: 10 parts by mass of a silane coupling agent, 8 parts by mass of sodium dihydrogen phosphate and 8 parts by mass of ethylene diether are mixed and added to a reactor, and then an initiator benzoyl peroxide is added, the initiator addition amount is 5% of the total mass of the system after the silane coupling agent and sodium dihydrogen phosphate are added, and 5 parts by volume of pentane are introduced, stirred at a speed of 220 r / min for 15 min, and heated to 40° C.;

[0120] S1.2: Add a mixed gas of ethylene and tetrafluoroethylene into the reactor, the molar mass ratio of ethylene to tetrafluoroethylene is 7:10, until the pressure in the reactor reaches 4 MPa, and react for 4 hours. During the reaction, keep adding the mixed gas of ethylene and tetrafluoroethylene to keep the pressure in the reactor at 4 MPa to obtain ETFE polymer;

[0121] S1.3: Extruding the ETFE polymer into a film through an extruder to obtain an ETFE film, and recording the prepared corrosion-resistant, aging-resistant and flame-retardant ETFE film as Comparative Example 4.

[0122] The flame retardant properties of Examples 1-3 and Comparative Examples 1-4 were tested according to UL94, as shown in Table 1.

[0123] Examples 1-3 and Comparative Examples 1-4 were tested according to GB / T1865-2009 to test their aging resistance. The sample size was 150 mm*70 mm*2 mm, as shown in Table 2.

[0124] Table 1

[0125]

[0126] Table 2

[0127] Contact Angle Example 1 153.4 Example 2 153.2 Example 3 152.6 Comparative Example 1 122.5 Comparative Example 2 134.9 Comparative Example 3 133.4 Comparative Example 4 124.6

[0128] The UL94 vertical burning ratings of Examples 1-3 are all V-0, while the UL94 vertical burning ratings of Comparative Examples 1-4 are distributed between V-1 and V-2. V-0 has the best flame retardancy, V-1 is inferior to V-0, and V-2 is inferior to V-1. The contact angles of Examples 1-3 are 153.4°, 153.2°, and 152.6°, respectively, with little difference. After aging, the larger the contact angle, the smoother the film surface.

[0129] The emulsion used in Comparative Example 1 is a dopamine-modified aramid fiber emulsion. Although aramid fiber also has a certain flame retardant ability, and dopamine can provide viscosity to make the ETFE film surface coating, since aramid fiber does not have a similar structure to ETFE film like polytetrafluoroethylene, the two cannot be further combined. Therefore, it can be seen that the flame retardant performance of Comparative Example 1 is slightly lower than that of the embodiment. However, after the aging test of Comparative Example 1, the contact angle is only 122.5°, compared with the lowest 152.6° of Embodiments 1-3, it can be seen that the surface roughness of Comparative Example 1 increases after aging, and the aramid fiber cannot fuse with the ETFE film after aging. The separation of the two causes a significant increase in the surface roughness, and the aging resistance of the ETFE film decreases.

[0130] The contact angle of Comparative Example 2 is 134.9°, and the contact angle of Comparative Example 3 is 133.4°, which is not much different. After aging, the larger the contact angle, the smoother the film surface. The contact angle of Comparative Examples 2-3 is lower than that of the embodiment. It can be seen that after the aging test, the film surfaces of Comparative Examples 2 and 3 have increased roughness and decreased performance;

[0131] Comparative Example 2 directly uses polytetrafluoroethylene instead of modified polytetrafluoroethylene microsphere powder, and its flame retardant grade is V-1, and the contact angle is 134.9°. It can be seen that polytetrafluoroethylene microspheres have lower surface energy than polytetrafluoroethylene, and the bonding area between polytetrafluoroethylene microsphere powder and polydopamine is larger. Combined with the excellent adhesion performance of polydopamine, the coating and the ETFE film are tightly bonded, thereby improving the flame retardant performance and aging resistance of the ETFE film.

[0132] Comparative Example 3 directly uses ETFE film without any coating to assist in providing flame retardancy, so the flame retardancy is also the most reduced, only V-2 level.

[0133] The flame retardant performance of comparative example 4 is V-1 level, but the contact angle is only 124.6°, which is the smallest among all comparative examples and embodiments. It can be seen that when pentane is directly added instead of brominated isopentane, the molecular weight of the ETFE polymer changes, resulting in a decrease in the physical strength of the ETFE film, which is less resistant to aging.

[0134] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A preparation process of a corrosion-resistant, aging-resistant and flame-retardant ETFE film, characterized in that: The steps include: S1: Preparation of ETFE polymer A silane coupling agent, sodium dihydrogen phosphate and ethylene diether are mixed and added into a reactor, an initiator is added, isopentyl bromide is introduced, and a mixed gas of ethylene and tetrafluoroethylene is introduced into the reactor for reaction to obtain an ETFE polymer, and the ETFE polymer is extruded into a film through an extruder to obtain an ETFE film; S2: Preparation of modified polytetrafluoroethylene microsphere powder First, deionized water is added to a reaction bottle, polytetrafluoroethylene and butyl acrylate are weighed in sequence and added to the reaction bottle, the reaction bottle is placed in a constant temperature water bath for heating and stirring, an ammonium persulfate solution is added to the reaction bottle, after the reaction, the product is collected by filtration and centrifugation to obtain modified polytetrafluoroethylene microspheres, the modified polytetrafluoroethylene microspheres obtained by centrifugation are dried, ground and sieved to obtain modified polytetrafluoroethylene microsphere powder, and the powder is stored in a dry environment for use; S3: Preparation of dopamine-modified polytetrafluoroethylene emulsion First, deionized water is added to a reaction bottle, tris(hydroxymethyl)aminomethane) is weighed into the reaction bottle, and hydrochloric acid is added to adjust the pH to obtain an acidic solution, modified polytetrafluoroethylene microsphere powder is weighed and added to the acidic solution, ultrasonically dispersed to obtain a modified polytetrafluoroethylene microsphere dispersion, dopamine hydrochloride is added to the modified polytetrafluoroethylene microsphere dispersion, and magnetic stirring is performed to obtain a dopamine-modified polytetrafluoroethylene emulsion; S4: Preparation of corrosion-resistant, aging-resistant and flame-retardant ETFE film The ETFE film was fixed on a dipping device and immersed in a dopamine-modified polytetrafluoroethylene emulsion, followed by drying, heating, annealing and cooling to obtain a modified ETFE film. The modified ETFE film was electron irradiated for 5 minutes at a irradiation dose of 10 Mrad to obtain a corrosion-resistant, aging-resistant and flame-retardant ETFE film.

2. The preparation process of a corrosion-resistant, aging-resistant and flame-retardant ETFE film according to claim 1, characterized in that: Step S1 prepares ETFE polymer, comprising the following steps: S1.1: 10-12 parts by mass of silane coupling agent, 8-10 parts by mass of sodium dihydrogen phosphate and 8 parts by mass of ethylene diether were mixed and added to a reaction kettle, and then an initiator was added, and 5 parts by volume of isopentyl bromide were introduced, and the mixture was stirred at a speed of 200-220 r / min for 10-15 min, and the temperature was raised to 40-50°C; S1.2: Add a mixed gas of ethylene and tetrafluoroethylene into the reactor until the pressure in the reactor reaches 4 MPa, and react for 4-4.5 hours. During the reaction, keep adding the mixed gas of ethylene and tetrafluoroethylene to keep the pressure in the reactor at 4 MPa to obtain ETFE polymer; S1.3: Extruding the ETFE polymer into a film through an extruder to obtain an ETFE film.

3. The preparation process of a corrosion-resistant, aging-resistant and flame-retardant ETFE film according to claim 2, characterized in that: Step S2 prepares modified polytetrafluoroethylene microsphere powder, comprising the following steps: S2.1: First, add 100 parts by mass of deionized water into a reaction bottle, and then weigh 25-30 parts by mass of polytetrafluoroethylene and 10-12 parts by mass of butyl acrylate and add them into the reaction bottle; S2.2: Place the reaction bottle in a constant temperature water bath for heating and stirring. When the temperature of the reaction system rises to 75°C, add 5 parts by weight of ammonium persulfate solution into the reaction bottle; S2.3: maintaining the temperature of the reaction system at 75°C and the stirring speed at 350-400 r / min, the reaction continued for 7-7.5 hours, and the product was collected by filtration and centrifugation to obtain modified polytetrafluoroethylene microspheres; S2.4: Dry the modified polytetrafluoroethylene microspheres obtained by centrifugation, grind them and pass them through an 80-mesh sieve to obtain modified polytetrafluoroethylene microsphere powder, and store it in a dry environment for future use.

4. The preparation process of the corrosion-resistant, aging-resistant and flame-retardant ETFE film according to claim 3, characterized in that: Step S3 prepares dopamine-modified polytetrafluoroethylene emulsion, comprising the following steps: S3.1: First, add 50 parts by weight of deionized water into a reaction bottle, weigh 0.06-0.08 parts by weight of tris(hydroxymethyl)aminomethane into the reaction bottle, and add hydrochloric acid to adjust the pH to 8.5 to obtain an acidic solution; S3.2: Weigh the modified polytetrafluoroethylene microsphere powder and add it to the acid solution, and disperse it by ultrasonic for 30-35 minutes to obtain a modified polytetrafluoroethylene microsphere dispersion; S3.3: Finally, 20-40 parts by weight of dopamine hydrochloride is added to the modified polytetrafluoroethylene microsphere dispersion, and the reaction is continued for 20-24 hours at room temperature with a magnetic stirring speed of 250 r / min to obtain a dopamine-modified polytetrafluoroethylene emulsion.

5. The preparation process of the corrosion-resistant, aging-resistant and flame-retardant ETFE film according to claim 4, characterized in that: Step S4 prepares the corrosion-resistant, aging-resistant and flame-retardant ETFE film, comprising the following steps: S4.1: After fixing the ETFE membrane on the dipping device, immerse it vertically in the dopamine-modified polytetrafluoroethylene emulsion at a speed of 5 mm / min, and then vertically pull it up at a speed of 5 mm / min after the ETFE membrane is completely immersed for 20 seconds; S4.2: then drying at 120°C for 10-12min, heating at 300-350°C for 4-5min, then annealing at 372°C for 4min, and finally naturally cooling at room temperature of 25°C to obtain a modified ETFE film; S4.3: The modified ETFE film is subjected to electron irradiation for 5 minutes at an irradiation dose of 10 Mrad to obtain a corrosion-resistant, aging-resistant and flame-retardant ETFE film.

6. The preparation process of the corrosion-resistant, aging-resistant and flame-retardant ETFE film according to claim 5, characterized in that: In step S1.1, the initiator is benzoyl peroxide, and the amount of the initiator added is 1-5% of the total mass of the system after the silane coupling agent and sodium dihydrogen phosphate are added.

7. The process for preparing the corrosion-resistant, aging-resistant and flame-retardant ETFE film according to claim 6, characterized in that: In step S1.2, the molar mass ratio of ethylene to tetrafluoroethylene in the mixed gas is 7:

10.

8. The process for preparing the corrosion-resistant, aging-resistant and flame-retardant ETFE film according to claim 7, characterized in that: The ammonium persulfate solution in step S2.2 is prepared by dissolving 0.15-0.2 parts by mass of ammonium persulfate in 5 parts by mass of deionized water and stirring the mixture uniformly.

9. The process for preparing the corrosion-resistant, aging-resistant and flame-retardant ETFE film according to claim 8, characterized in that: In step S3.2, the mass ratio of modified polytetrafluoroethylene microsphere powder to acid solution is (0.1-0.5):

50.

10. A corrosion-resistant, aging-resistant and flame-retardant ETFE film, which is prepared by the preparation process of the corrosion-resistant, aging-resistant and flame-retardant ETFE film according to any one of claims 1 to 9.

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