noun which may take the genitive case particle 'no'
for children; for use by children
Indicates that something is designed, intended, or suitable for children. Commonly used as a modifier before nouns.
This chair is for children.
I bought a toothbrush for children.
I bought him a child-sized bicycle.
This recipe has been made milder for children.
子供用 describes something made for children, while 大人用 describes the same kind of thing made for adults.
Compound of 子供 (child) and 用 (use, purpose). The reading is a straightforward combination of the two components.