I have had problems with needles becoming dull very quickly when sewing batiks. I adore them--as the two shelves worth in my sewing room can attest to--but have found them hard to sew.
I have just discovered microtex needles and find that they sew thru batiks much better than my regular needles. Then, a few days ago, I started making a bag using Bosal interfacing--you know the stuff that makes your bags really really hold their shape? Today, I was doing the side seams, so I had to go thru 6 layers of fabric ( front, side and pocket plus 3 layers of lining fabric) 2 layers of Bosal, and a layer of the thinner batting I had used for the pocket. That microtex needle went thru it all with no problem at all. It will definitely be my go-to needle now.