Felt has a long association with the nomadic peoples of the Mongolian steppe - yurts (蒙古包), saddle blankets, and boots are classic 毡 products. Common compounds: 毡帽 felt hat, 毛毡 wool felt, 油毡 tar paper / asphalt felt.
memory
The radical 毛 'fur / wool' on the left tells you immediately the material is matted animal hair.
毛 on the lower-left is the indexing radical, picturing a tuft of hair. It tags 毡 as a wool product and groups it with other fur-and-fibre words; felt is precisely matted wool pressed flat without weaving.
占 supplies the reading zhān directly with no shift. The same phonetic appears in 沾 (moisten), 站 (stand), and 粘 (sticky), pinning a tight family around the zhan syllable.
