Trade secret of composition so as not to be copied/modified by the competition. Polymer technology is special indeed and $ELTP's R&D knew exactly how to interconnect to prevent attacks against all the body fluids. But then you know this as the reason why $ELTP was granted Patent 8,703,186 for their original invention.
But but but... it is not the composition of the polymer itself that is so unique to Elites application doctor. We have been through this matter over and over and over. Please pay attention to what has been discussed.