Introduction Paper and paperboard Paperboard, boxboard, cardboard, and cartonboard are all terms used to describe heavier paper stock The International Organization for Standardization(Iso) states that material weighing more than 250 grams per square metre(511b per 1,000 sq ft )shall be known as paperboard. U.S. practice calls material that is more than 300(0.012 in. thick paperboardIntroduction Paper and paperboard · Paperboard, boxboard, cardboard, and cartonboard are all terms used to describe heavier paper stock. · The International Organization for Standardization (ISO) states that material weighing more than 250 grams per square metre (511b per 1,000 sq. ft.) shall be known as paperboard. U.S. practice calls material that is more than 300(0.012 in.) thick paperboard