PAPER MADE OF STONE
In the late 1990s, Taiwanese company Lung Meng Tech developed a papermaking technology using calcium carbonate and high-density polyethene instead of cellulose. The new technology soon gained considerable popularity and in the years that followed, stone paper, as it was named because of the mineral powder used to make it, was patented in 40 different countries around the world.
The main component of stone paper – approx. 80% – is calcium carbonate (CaCO3). In nature, calcium carbonate makes up more than 4% of the Earth’s crust and it is an essential component of many minerals, such as calcite and aragonite, which play an important role in rock formation processes. It also occurs in large quantities in water, usually in the form of calcium bicarbonate Ca(HCO3)2. Through water, it is absorbed into the body of animals and used in the formation of bones.
The second basic component of stone paper is HDPE (High-Density Polyethylene). This polymer is widely used in the manufacture of plastic products such as bottles, caps and more. Due to its elasticity and strength, it serves as a binder in the production of stone paper.
Stone paper is similar in thickness to traditional paper but has a smoother surface. It can be successfully used in inkjet printers – it is not suitable for laser printers due to its sensitivity to high temperatures. It is used in the production of all kinds of paper products, especially packaging, maps, notebooks, trays, etc. It is resistant to water and grease and is more difficult to tear than ordinary paper. For this reason, it is used in products that are designed to be more resistant to damage and wear.
Stone paper is also environmentally friendly, which is one of its main advantages. The production of traditional paper requires the use of large amounts of water and the need to cut down trees. The production of stone paper, on the other hand, does not require the use of water at all, and if the paper is left in nature for about a year, it breaks down into a completely natural and harmless mineral powder that can be reused in paper production. Its combustion does not release any toxic compounds into the atmosphere. It can also be recycled. In addition, it is photodegradable, i.e. it degrades due to prolonged exposure to sunlight.
Several advantages can be attributed to stone paper that speak strongly in favour of its use. It is pleasant to the touch while appearing to be velvety – marketers immediately called it “luxurious to the touch” – and it is also an interesting curiosity among promotional items. It has an eye-pleasing shade of white. Its tear resistance is noticeably higher than traditional paper. For people who pay attention to environmental issues, it is a good alternative to paper produced using traditional methods. The energy requirements for the production of stone paper are half that of traditional paper. Higher stiffness combined with a lower environmental burden may in the future lead to stone paper completely replacing its “big brother” and becoming the material of choice for most paper products. For now, it remains an interesting oddity waiting to awaken more interest from potential users.
Source: Kurier kamieniarski
Author: Jakub Zdańkowski | Published: 18.6.2015