floor and loft Kingspan insulation equivalents

[nanuuk]

Hi,
I was wondering if there are any equivalents to Kingspan K7, K18, K3 that might be a lot cheaper but just as good?
Does any of them have acoustic insulation properties or which Kingspan does?
Cheers, much appreciated.

 

[mointainwalker]

Sound-insulation properties of stiff boards are generally reckoned to be poor as the board acts like a membrane and transmits rather than damps sound. Fibre-wool is better.

 

[cpm25]

quin therm a good alternative