Conservative certainly believe in free association and that has to go for trade unions as well.
The history is muccy and they bare corrupt in many cases but there are plenty of good unionn workers that belong due to thier locale or job and will vote with us if not made to feel outside the fold.
What part of free are you speaking about? In my world, it is a MERITOCRACY. Excellence begets superior results. Superior results beget profits, and it usually reaps a reward. Unions are socialist, not free association. You need to get a better conservative dictionary.
"Workers of the world, unite". Sound familiar?