Hydrophilic nichrome heating wire, its preparation method and application

Abstract

The application discloses a hydrophilic nickel-chromium heating wire, and belongs to the technical field of the nickel-chromium heating wire.The hydrophilic nickel-chromium heating wire is characterized in that a titanium dioxide / Ti3C2Tx composite coating layer is coated on the surface of the nickel-chromium heating wire, and the thickness of the titanium dioxide / Ti3C2Tx composite coating layer is 1-5 microns.The application further discloses a preparation method of the hydrophilic nickel-chromium heating wire and a cleaning application of the hydrophilic nickel-chromium heating wire for electronic cigarette liquid adhesive.

Description

Technical Field

[0001] This invention belongs to the field of tobacco technology, specifically relating to a hydrophilic nickel-chromium heating wire, its preparation method, and its application in preventing the gelatinization and sintering of tobacco liquid. Background Technology

[0002] Electronic cigarettes are devices that atomize nicotine-containing or nicotine-free e-liquid into an aerosol for users to inhale. As a type of non-combustible, low-harm new tobacco product with great development potential, they have sparked a health consumption craze worldwide because they are similar to traditional cigarettes in terms of physiological sensations, psychological perceptions, and smoking methods. The global development of electronic cigarettes is very rapid, with market share increasing year by year and the consumer group growing and becoming younger.

[0003] Electronic cigarettes are activated by airflow sensors or mechanical buttons, which power the control circuitry to supply electricity to heating components such as metal heating wires or porous ceramic heating elements. This heats the e-liquid, causing it to atomize and produce an aerosol. Among the many heating components, nickel-chromium heating wires are widely used in commercially available electronic cigarettes due to their high electrothermal conversion efficiency and durability.

[0004] However, during use, e-liquid adheres to the surface of the nickel-chromium heating wire, and some of its components undergo cross-linking and gelatinization under high temperatures. These gelatinized products adhere to the surface of the heating wire, forming carbon deposits. This not only affects the heating efficiency of the wire but also produces a distinctive odor, impacting the user's vaping experience. The adhesion of e-liquid to the heating wire surface is a significant factor contributing to gelatinization and carbon buildup.

[0005] Patent CN111165904A designs a sol-gel layer and a low surface energy layer on the surface of the nickel-chromium wire, resulting in a contact angle of the e-liquid with the nickel-chromium heating wire greater than 150°, and an adhesion amount of the e-liquid to the surface of the nickel-chromium heating wire less than 5 wt%. However, after a period of use, CN111165904A still shows a relatively large amount of carbon buildup on the surface of the nickel-chromium wire.

[0006] Using a hydrophilic nickel-chromium wire makes it easier to wash away the e-liquid after it adheres to the wire, resulting in a more effective and efficient cleaning process.

[0007] The present invention is proposed to solve the above problems. Summary of the Invention

[0008] This invention discloses a hydrophilic nickel-chromium heating wire, its preparation method, and its applications. The invention involves coating the surface of the nickel-chromium heating wire with a titanium dioxide / Ti3C2Tx composite coating layer, which provides improved hydrophilicity and flue gas cleaning properties. The invention also discloses a method for preparing the nickel-chromium heating wire.

[0009] The technical solution of the present invention is as follows:

[0010] The first aspect of the present invention discloses a hydrophilic nickel-chromium heating wire, wherein a titanium dioxide / Ti3C2Tx composite coating layer is provided on the surface of the nickel-chromium heating wire, and the thickness of the titanium dioxide / Ti3C2Tx composite coating layer is 1-5 μm.

[0011] Preferably, the contact angle between water and the nickel-chromium heating wire is greater than 20°, and the amount of flue liquid adhering to the surface of the nickel-chromium heating wire after rinsing with water is less than 0.2 wt%.

[0012] Preferably, the water rinsing involves soaking in deionized water for a period of time, generally not less than 5 minutes.

[0013] Preferably, the titanium dioxide / Ti3C2Tx composite coating is a coating in which Ti3C2Tx nanosheets are mixed in with titanium dioxide; the Ti3C2Tx nanosheets have a size of 100nm-500nm and a thickness of 20-100nm.

[0014] Preferably, the amount of the Ti3C2Tx nanosheets is 1-10 wt% of the amount of titanium dioxide.

[0015] The second aspect of this invention discloses a method for preparing the hydrophilic nickel-chromium heating wire, comprising the following steps:

[0016] (1) After ultrasonicating the nickel-chromium wire in sodium hydroxide solution for a period of time, ultrasonically clean it with acetone and anhydrous ethanol for more than 10 minutes each, then rinse it with anhydrous ethanol several times and let it air dry at room temperature.

[0017] (2) Place the nickel-chromium wire from step (1) in an acid solution and etch it at a certain temperature, then wash it with water and let it air dry at room temperature.

[0018] (3) Prepare titanium dioxide / Ti3C2Tx composite sol, coat the nickel-chromium wire from step (2) with titanium dioxide / Ti3C2Tx composite sol, and then heat treat it at a certain temperature for a period of time to obtain the nickel-chromium heating wire.

[0019] Preferably, the sodium hydroxide solution in step (1) is 0.5M-2M and is sonicated at 20-40℃ for more than 30 minutes.

[0020] Preferably, the acid solution in step (2) is a 10-20 wt% hydrochloric acid solution or a 0.1-1 wt% HF solution; the etching temperature is 20-60℃ and the etching time is 1-60h.

[0021] Preferably, the heat treatment temperature in step (3) is 120-200℃ and the time is 1-12h.

[0022] Preferably, the preparation method of the titanium dioxide / Ti3C2Tx composite sol in step (3) includes the following steps:

[0023] (A) Add titanate to anhydrous ethanol, stir and react at room temperature for a period of time, then add glacial acetic acid and react at room temperature for a period of time to obtain titanium dioxide sol.

[0024] (B) Add the Ti3C2Tx ethanol solution to the sol obtained in step (A) and disperse it by ultrasonication for a period of time to obtain the titanium dioxide / Ti3C2Tx composite sol.

[0025] Preferably, the amount of the Ti3C2Tx nanosheets is 1-10 wt% of the amount of titanium dioxide.

[0026] The third aspect of this invention discloses the application of the hydrophilic nickel-chromium heating wire for cleaning adhesives in electronic cigarette liquid.

[0027] The beneficial effects of this invention are:

[0028] 1. The hydrophilic nickel-chromium heating wire of the present invention comprises a titanium dioxide / Ti3C2Tx composite coating layer with a thickness of 1-5 μm coated on the surface of the nickel-chromium heating wire. The contact angle of the e-liquid with the nickel-chromium heating wire having the composite coating layer is less than 30°, and the contact angle of water with the nickel-chromium heating wire is less than 20°. After rinsing with water (generally soaking in deionized water for no less than 5 mins), the amount of e-liquid adhering to the surface of the nickel-chromium heating wire is less than 0.2 wt%.

[0029] 2. The preparation method of the nickel-chromium heating wire of the present invention is simple. Detailed Implementation

[0030] The present invention will be further described in detail below through specific embodiments, but it should not be construed as limiting the scope of the invention to the following examples. Various substitutions and modifications made based on ordinary technical knowledge and conventional methods in the art without departing from the spirit of the invention should be included within the scope of the invention.

[0031] Example 1: Preparation of a hydrophilic nickel-chromium heating wire, the steps are as follows:

[0032] (1) After sonicating the nickel-chromium wire in a 1M sodium hydroxide solution at 30℃ for more than 30 minutes, it was ultrasonically cleaned with acetone and anhydrous ethanol for 20 minutes each, then rinsed three times with anhydrous ethanol and dried at room temperature.

[0033] (2) Place the nickel-chromium wire from step (1) in a 15wt% hydrochloric acid solution and etch it at 30°C for 30 hours. Then wash it with water and let it air dry at room temperature.

[0034] (3) Coat the nickel-chromium wire from step (2) with titanium dioxide / Ti3C2Tx composite sol, and then heat-treat it at 120°C for 12 hours to obtain the nickel-chromium heating wire.

[0035] The preparation method of titanium dioxide / Ti3C2Tx composite sol includes the following steps:

[0036] (A) Add 0.002 mol of tetrabutyl titanate to 200 ml of anhydrous ethanol and stir at room temperature for 24 h. Then add 0.1 ml of glacial acetic acid and react at room temperature for 96 h to obtain titanium dioxide sol.

[0037] (B) Add 5 ml of ethanol solution containing 1 wt% Ti3C2Tx to the titanium dioxide sol obtained in step (A) and sonicate for 30 mins to obtain the titanium dioxide / Ti3C2Tx composite sol.

[0038] The contact angle of water with the resulting hydrophilic nickel-chromium wire was 16°.

[0039] The results of evaluating the obtained nickel-chromium heating wire using commonly used e-cigarette liquids are as follows:

[0040]

[0041] [Note] The nickel-chromium substrate used for the contact angle test is a nickel-chromium sheet. The nickel-chromium substrate used for the e-liquid adhesion test is a nickel-chromium wire. The procedure is as follows: the nickel-chromium wire is heated 100 times in the e-liquid, then soaked in deionized water for 5 minutes, and dried in an oven at 80°C. The mass of the nickel-chromium wire before and after 100 heating cycles in the e-liquid is measured, and the percentage of the excess mass after sample cleaning is recorded.

[0042] Example 2: Preparation of a hydrophilic nickel-chromium heating wire, the steps are as follows:

[0043] (1) After sonicating the nickel-chromium wire in a 1M sodium hydroxide solution at 30℃ for more than 30 minutes, it was ultrasonically cleaned with acetone and anhydrous ethanol for 20 minutes each, then rinsed three times with anhydrous ethanol and dried at room temperature.

[0044] (2) Place the nickel-chromium wire from step (1) in a 15wt% hydrochloric acid solution and etch it at 30°C for 30 hours. Then wash it with water and let it air dry at room temperature.

[0045] (3) Coat the nickel-chromium wire from step (2) with titanium dioxide / Ti3C2Tx composite sol, and then heat-treat it at 200°C for 12 hours to obtain the nickel-chromium heating wire.

[0046] The preparation method of titanium dioxide / Ti3C2Tx composite sol includes the following steps:

[0047] (A) Add 0.002 mol of tetrabutyl titanate to 200 ml of anhydrous ethanol and stir at room temperature for 24 h. Then add 0.1 ml of glacial acetic acid and react at room temperature for 96 h to obtain titanium dioxide sol.

[0048] (B) Add 5 ml of ethanol solution containing 6 wt% Ti3C2Tx to the titanium dioxide sol obtained in step (A) and sonicate for 30 mins to obtain the titanium dioxide / Ti3C2Tx composite sol.

[0049] The contact angle between water and the resulting nickel-chromium wire is less than 18°.

[0050] The results of evaluating the obtained nickel-chromium heating wire with commonly used e-cigarette liquids are the same as in Example 1.

[0051] Example 3: Preparation of a hydrophilic nickel-chromium heating wire, the steps are as follows:

[0052] (1) After sonicating the nickel-chromium wire in a 1M sodium hydroxide solution at 30℃ for more than 30 minutes, it was ultrasonically cleaned with acetone and anhydrous ethanol for 20 minutes each, then rinsed three times with anhydrous ethanol and dried at room temperature.

[0053] (2) Place the nickel-chromium wire from step (1) in a 15wt% hydrochloric acid solution and etch it at 30°C for 30 hours. Then wash it with water and let it air dry at room temperature.

[0054] (3) Coat the nickel-chromium wire from step (2) with titanium dioxide / Ti3C2Tx composite sol, and then heat-treat it at 160°C for 12 hours to obtain the nickel-chromium heating wire.

[0055] The preparation method of titanium dioxide / Ti3C2Tx composite sol includes the following steps:

[0056] (A) Add 0.002 mol of tetrabutyl titanate to 200 ml of anhydrous ethanol and stir at room temperature for 24 h. Then add 0.1 ml of glacial acetic acid and react at room temperature for 96 h to obtain titanium dioxide sol.

[0057] (B) Add 5 ml of ethanol solution containing 10 wt% Ti3C2Tx to the titanium dioxide sol obtained in step (1) and sonicate for 30 mins to obtain the titanium dioxide / Ti3C2Tx composite sol.

[0058] The contact angle between water and the resulting nickel-chromium wire is less than 15°.

[0059] The results of evaluating the obtained nickel-chromium heating wire with commonly used e-cigarette liquids are the same as in Example 1.

[0060] The embodiments described are merely preferred embodiments of the present invention and are not intended to limit the invention. Various modifications and variations can be made to the invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A hydrophilic nickel-chromium heating wire, characterized in that, A titanium dioxide / Ti3C2Tx composite coating layer with a thickness of 1-5 μm is applied to the surface of the nickel-chromium heating wire; the contact angle of water with the nickel-chromium heating wire is less than 20°, and the amount of flue gas adhering to the surface of the nickel-chromium heating wire after water rinsing is less than 0.2 wt%; the water rinsing is performed by immersion in deionized water for 5 minutes. The preparation method of the hydrophilic nickel-chromium heating wire includes the following steps: (1) After ultrasonicating the nickel-chromium wire in sodium hydroxide solution for a period of time, ultrasonically clean it with acetone and anhydrous ethanol for more than 10 minutes each, rinse it with anhydrous ethanol several times, and then let it air dry at room temperature. (2) Place the nickel-chromium wire from step (1) in an acid solution and etch it at a certain temperature, then wash it with water and let it air dry at room temperature; (3) Prepare titanium dioxide / Ti3C2Tx composite sol, coat the nickel-chromium wire from step (2) with titanium dioxide / Ti3C2Tx composite sol, and then treat it at 120-200℃ for 1-12h to obtain the hydrophilic nickel-chromium heating wire. The preparation method of titanium dioxide / Ti3C2Tx composite sol includes the following steps: (A) Add titanate to anhydrous ethanol, stir and react at room temperature for a period of time, then add glacial acetic acid and react at room temperature for a period of time to obtain titanium dioxide sol. (B) Add the Ti3C2Tx ethanol solution to the sol obtained in step (A) and disperse it by ultrasonication for a period of time to obtain the titanium dioxide / Ti3C2Tx composite sol.

2. The hydrophilic nickel-chromium heating wire according to claim 1, characterized in that, The titanium dioxide / Ti3C2Tx composite coating consists of Ti3C2Tx nanosheets mixed in a titanium dioxide coating.

3. The hydrophilic nickel-chromium heating wire according to claim 2, characterized in that, The amount of the Ti3C2Tx nanosheets is 1-10 wt% of the amount of titanium dioxide.

4. The hydrophilic nickel-chromium heating wire according to claim 1, characterized in that, The sodium hydroxide solution in step (1) is 0.5M-2M, and the sodium hydroxide solution is sonicated at 20-40℃ for more than 30 minutes.

5. The hydrophilic nickel-chromium heating wire according to claim 1, characterized in that, The acid solution in step (2) is a 10-20 wt% hydrochloric acid solution or a 0.1-1 wt% HF solution; the etching temperature is 20-60℃ and the etching time is 1-60h.

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