American appeal for help securing top quality insulating material (8)
I believe the answer is:
asbestos
'insulating material' is the definition.
(I've seen this before)
'american appeal for help securing top' is the wordplay.
'american' becomes 'a' (common abbreviation - e.g. in organisation names).
'appeal for help' becomes 'sos' (I've seen this before).
'securing' indicates putting letters inside.
'top' becomes 'best' ('best' can be similar in meaning to 'top'**).
'sos' enclosing 'best' is 'sbestos'.
'a'+'sbestos'='ASBESTOS'
'quality' acts as a link.
This may not be right. It may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for asbestos that I've seen before include "I might end up lagging" , "Fire-resistant material dangerous to health" , "you can't inflame this" , "Fire-resistant material, injurious to health" , "Heat-resistant fibre" .)