acid-free
adjective uk/ˌæs.ɪdˈfriː/ us/ˌæs.ɪdˈfriː/
无酸的
Acid-free paper does not contain any harmful acid that can damage documents, paintings, etc.
The books are printed on acid-free paper so they will last for generations. 这些书是用无酸纸印刷的，寿命很长。