Moisture-proof processing method for filter stick capsules

The invention provides a moisture-proof processing method for filter stick capsules. The method comprises the following steps: (1) firstly, preparing Pulullan into aqueous solution according to a proportion of 1:10-200 and using the aqueous solution as coating liquid for later use; (2) coating semi-finished filter stick capsules; (3) placing coated filter stick capsules into a rotary cage and performing sizing and pre-drying; (4) placing the filter stick capsules, subjected to the sizing and the pre-drying, into a drying room with the humidity which is 20-40%, laying, standing and drying for 24h; gathering and removing interior-quality filter stick capsules, thereby obtaining finished filter stick capsules. According to the moisture-proof processing method for the filter stick capsules, a Pulullan coating membrane is formed on the external surface of a wall material of each filter stick capsule, thus waterproof and moisture-proof properties can be improved; under an influence of air humidity or moisture in main stream smoke of cigarettes, the filter stick capsules are still fragile and give out rattling voices during breaking.