English to Portuguese Law/Patents Electronics / Elect Eng

My doubt is related to the use of "first" and "second" here... Even though this could indicate "first particles" or "second particles", something tells me that this is related to the order in which these particles become electrically conductive... Any hints?

"The material has a substantially non-conductive polymer with first electrically conductive particles that have void-bearing structures in combination with second electrically conductive particles that are acicular in shape"