Stone paper products, also referred to as bio-plastic paper, mineral paper or rich mineral paper, are strong and durable paper-like materials manufactured from calcium carbonate bonded with high-density polyethylene (HDPE) resin. They are used in many of the same applications as cellulose-based paper.[1][2]
Stone "paper" consists of roughly 80% calcium carbonate, 18% HDPE and 2% proprietary coating.[3]. It has a density range of 1.0–1.6 g/cm3 (0.58–0.92 oz/cu in), which is equal to or slightly higher than that of ordinary paper, and a texture somewhat like that of the outer membrane of a boiled egg. It is not biodegradable or compostable, but is photo-degradable by the ultraviolet (UVa) light in daylight.[4] Thus stone "paper" does not meet archival standards and requires special measures for long-term conservation.
Because it is not made from cellulose fibers, stone paper can have a smoother surface than most traditional products, eliminating the need for additional coating or lamination.[5] The calcium carbonate is mined from quarries or precipitated from limestone.[3] The production of stone paper uses no acid, bleach or optical brighteners.[6] It can be recycled into new stone paper, but only if recycled separately at dedicated civic amenity sites or other recycling/waste processing points.[7][6]
Stone paper products are compatible with inkjet or solid ink printers (e.g., offset, letterpress, gravure, flexographic) but do not respond well to very high temperature laser printers.[8][9]
Comparisons have been made between stone paper and traditional paper for applications like book printing in Europe.[10] If stone paper replaced coated and uncoated graphic printing stock in Europe, it could potentially reduce CO₂ emissions by 25% to 62%, water consumption by 89% to 99.2%, and wood usage by 100% compared to current European consumption, which is mostly of virgin paper.[3][11] The environmental benefits of stone paper relative to recycled paper are much less substantial.[3][12][13]