Q.1033: How is paper made waterproof?

Ans. Paper can be made waterproof or water resistant by one of the following methods, depending on the end use.

By heavily beating the pulp and forming a compact and dense sheet which will resist water or other fluid penetration. e.g. Greaseproof paper
By coating with a waterproof material layer. e.g. wax paper
By lamination with a waterproof material film such as plastic or aluminum. e.g. Aluminum Foil Paper
By soaking paper in chemical such as mineral oil.