Palmin is the same as Copha, except there are two varieties: one comes in a tub, which is almost spreadable, and the other comes in a block like Copha.
The blocks come in 250g (1/2 pound) portions. Available in many European delicatessens in North America.
Substitutes
Coconut butter or 2 parts shortening or lard, with 1 part creamed coconut.