A kind of electrothermal film with PTC effect and preparation method thereof

An electrothermal film and effect technology, applied in electrothermal devices, ohmic resistance heating, electrical components, etc., can solve problems such as difficulty in achieving PTC effect, poor mechanical properties, poor dimensional stability, and poor film formation

Active Publication Date: 2021-07-13
EAST CHINA UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The disadvantage of this type of technology is that: as the supporting material of the electrothermal film, the polymer needs to have good mechanical properties and dimensional stability, and the realization of the PTC effect depends on the volume expansion of the support after being heated, and the polymer support needs to be simultaneously Provide thermal expansion ability and mechanical properties and dimensional stability of the system, which is difficult to balance in actual use
Generally, materials with a large volume thermal expansion rate have poor mechanical properties and heat resistance, and the thermal stability of the electrothermal film is poor and film-forming properties are relatively poor; while materials with good mechanical properties and film-forming properties have a small volume thermal expansion rate. , it is even difficult to realize the PTC effect
For example, the common electric heating rubber and electric heating nylon, the former uses rubber as the matrix, has good thermal expansion performance, and can effectively realize the PTC effect, but the mechanical properties and dimensional stability are poor; the latter uses nylon as the matrix, the mechanical properties and dimensions Excellent stability, but the volumetric thermal expansion rate is very small, only conductive heat generation can be realized, and PTC effect and self-limiting temperature cannot be realized

Method used

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  • A kind of electrothermal film with PTC effect and preparation method thereof
  • A kind of electrothermal film with PTC effect and preparation method thereof
  • A kind of electrothermal film with PTC effect and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0043] The preparation steps and formula of this embodiment are as follows:

[0044] 1. Hydrophilic surface treatment of carbon fiber short fibers: the carbon fiber short fibers used have a length of 150 microns and a diameter of 7 microns. Get 100 grams of carbon fiber short fiber and add it to deionized water to immerse the carbon fiber, and treat it ultrasonically for 30 minutes; place the carbon fiber after the ultrasonic treatment in a solution of Tris (Tris) to immerse the carbon fiber, and the tris in the solution The concentration of methane is 0.015 mol / liter; add 40 g of dopamine hydrochloride and stir to dissolve the dopamine hydrochloride; add 1 mol·L-1 of HCl to adjust the pH of the solution to 8.5; stir at room temperature and allow it to react for 20 hours. Finally, the surface-treated short carbon fiber is repeatedly rinsed with deionized water until the washing liquid is colorless, and then the short carbon fiber is dried to obtain the short carbon fiber whose...

Embodiment 2

[0049] Different from Example 1, in the second step, it is:

[0050] 2. Prepare conductive carbon paste: in the reactor equipped with stirring device, add 21 grams of short carbon fiber through dopamine surface treatment, then add 37.4 grams of poly(N-isopropylacrylamide), and add 30 grams of water, Stir until the carbon fibers can be uniformly dispersed in the mixing system without settling, and the conductive carbon paste is prepared.

[0051] All the other steps are the same as in Example 1.

[0052] The finished product in this embodiment is subjected to a performance test, and the results of the power-on test are shown in the attached image 3 .

Embodiment 3

[0054] Different from Example 1, in the second step and the third step, it is:

[0055] 2. Preparation of conductive carbon paste: In a reaction kettle equipped with a stirring device, add 21 grams of carbon fiber short fibers treated with dopamine surface, then add 47 grams of polymethacrylamide, and add 30 grams of water, stir to prepare conductive carbon paste .

[0056] 3. Preparation of electric heating film: add 100 grams of prepared conductive carbon paste to 190 grams of polyurethane emulsion, the solid content of polyurethane emulsion is 50%, and stir for 30 minutes; operate the coating machine to coat on the non-woven fabric, coating The thickness is 120μm, and it is dried after coating.

[0057] All the other steps are the same as in Example 1.

[0058] The finished product in this embodiment is subjected to a performance test, and the results of the power-on test are shown in the attached Figure 4 .

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Abstract

The invention belongs to the technical field of electrothermal materials, and relates to an electrothermal film with PTC effect and a preparation method thereof. The method: firstly treat the surface of the short carbon fiber with dopamine; add the treated carbon fiber into the hydrophilic polymer with a weight ratio of 25-60%, make it evenly distributed, and make a carbon slurry; Add 70% to the polyurethane emulsion with a solid content of 50‑65%, mix evenly, and coat it on the substrate to prepare an electric heating film with a film thickness of 50‑150 μm. Dopamine forms a hydrophilic coating on the surface of carbon fiber staple fibers. Since the hydrophilic polymer is incompatible with polyurethane, the system is a bicontinuous phase. Carbon fiber staple fibers are mainly distributed in hydrophilic polymers, and polyurethane is the supporting material for electric heating membranes. . In the present invention, since the supporting material does not need to provide volume expansion effect, polyurethane with small thermal expansion coefficient and good dimensional stability can be selected, and the finished product has better PTC effect and dimensional stability.

Description

technical field [0001] The invention belongs to the technical field of electrothermal materials, and relates to an electrothermal film with a PTC effect and a preparation method thereof, in particular to a technology and method for preparing an electrothermal film with carbon fiber short fibers as conductive fillers and polymers as supporting materials. The invention is used to prepare a high molecular electric heating film capable of heating and self-limiting temperature when energized, and is used to replace the traditional high molecular electric heating film which cannot self-limit temperature. Background technique [0002] The material with PTC (Positive Temperature Coefficient) effect refers to a kind of thermistor material with positive temperature coefficient. Its main feature is that when the temperature of the material rises to a certain temperature, the resistivity of the material will increase rapidly. Conductors become poor conductors or even insulators. Becaus...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H05B3/14H05B3/20H05B3/34D06N3/14D06N3/00
CPCD06N3/0063D06N3/14H05B3/145H05B3/20H05B3/347
Inventor 刘小云朱鹏飞谭正洪林
Owner EAST CHINA UNIV OF SCI & TECH
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