You could probably get some filter material at Home Depot or Lowes and cut your own. If your filter looks like what I suspect, it's just rectangular and would be easy to replicate.
I'm surprised it did disintegrate though. I cleaned the one in my '94 a couple times and it was still like new. Put it under running water and scrubbed it with my hands and some soap.
2007 T-286SR Cherry/Granola, #6236, original owner, current mileage: 9473.8 (as of 6/18/21)
1997 T-2653 Blue Denim, #5471
1979 12 1/2' MC, Beige & Avocado, #4639
Past Sunlines: '97 T-2653 #5089, '94 T-2251, '86 T-1550, '94 T-2363, '98 T-270SR