Method for preparing electrothermal heating sheet from carbon fiber braided fabric scraps

A method for preparing an electrothermal heating sheet from carbon fiber braided fabric scraps, comprising the following steps:

• step 1) trimming:
• cutting clumps of disordered carbon fiber braided fabric scraps with a cutting length controlled to be 5 mm to 10 mm to obtain chopped carbon fibers;
• step 2) standing:
• adding the chopped carbon fibers into a beaker containing acetone and standing the chopped carbon fibers in a ventilation environment for 10 h to 14 h;
• step 3) washing and drying:
• repeatedly washing the chopped carbon fibers after the standing by separately using acetone and deionized water, and drying in a drying oven to obtain dried chopped carbon fibers;
• step 4) preparation of a dispersion:
• adding deionized water and absolute ethyl alcohol into two containers, respectively;
• dispersing a sodium carboxymethyl cellulose powder in the absolute ethyl alcohol, wherein a ratio of the sodium carboxymethyl cellulose powder to the absolute ethyl alcohol is in a range of 1 g:10-13 mL, and a volume ratio of the deionized water to the absolute ethyl alcohol is in a range of 8:1 to 10:1;
• and fully mixing the absolute ethyl alcohol dispersed with the sodium carboxymethyl cellulose powder with the deionized water to form the dispersion;
• step 5) preparation of a chopped carbon fiber dispersion:
• adding 1 g to 2 g of the dried chopped carbon fibers obtained in step 3) into the dispersion and fully stirring to make the dried chopped carbon fibers be fully dispersed in the dispersion to form the chopped carbon fiber dispersion;
• step 6) formation of a chopped carbon fiber felt sheet:
• guiding the chopped carbon fiber dispersion into a Buchner funnel with a double-layer metal screen, fully stirring and standing for 10 min, and turning on a vacuum filtration device and performing vacuum filtration to obtain the chopped carbon fiber felt sheet, wherein a gram weight of the chopped carbon fiber felt sheet is in a range of 10 g/m2 and 80 g/m2;
• step 7) drying:
• taking down an upper metal screen with the chopped carbon fiber felt sheet, and drying in a drying oven to obtain a circular chopped carbon fiber felt, and cutting the circular chopped carbon fiber felt to obtain a cut chopped carbon fiber felt;
• step 8) making of electrodes:
• sticking electrodes to two ends of the cut chopped carbon fiber felt by uniformly coating a silver conductive adhesive onto the electrodes and sticking to the two ends of the chopped carbon fiber felt, and then drying a resulting chopped carbon fiber felt in a drying oven to obtain a carbon fiber felt sheet with the electrodes;
• step 9) preparation of a thermoplastic polyurethane (TPU) sheet:
• drying TPU particles in a drying oven to remove moisture to obtain dried TPU particles, and then preparing the dried TPU particles into a TPU sheet by using a vacuum laminator, wherein a thickness of the TPU sheet is controlled to be 0.1 mm to 2 mm;
• and
• step 10) forming of a product:
• sandwiching one layer of the chopped carbon fiber felt with the electrodes between two layers of the TPU sheet, and subjecting a resulting system to plastic packaging by a vacuum laminator to obtain the electrothermal heating sheet.