Ronald always content with the material (5)
I believe the answer is:
rayon
'the material' is the definition.
(rayon is a kind of material)
'ronald always content' is the wordplay.
'ronald' becomes 'ron' (I've seen this in other clues).
'always' becomes 'ay'.
'content' indicates putting letters inside.
'ron' enclosing 'ay' is 'RAYON'.
'with' is the link.
(Other definitions for rayon that I've seen before include "Artificial material" , "Synthetic fibre" , "Viscose fibre" , "Man-made fibre" , "No ray (anag)" .)