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At Sappi, the papermaking process starts with responsibly managed forests, renewable energy-powered mills, and ends with our coated fine papers being shipped off to merchants and print shops all over the globe. If you want to learn more about what it takes to turn raw materials into the beautiful magazine or catalog on your desk, simply read through the diagram below.
At Sappi Fine Paper North America we buy wood from responsible landowners who practice sustainable forestry. This ensures a healthy and vibrant forest through the use of Best Management Practices appropriate for the conditions. BMPs address the ecosystem as a whole and take into consideration water quality, soil stabilization, regeneration, wildlife, harvest techniques, as well as relevant social concerns.
Our paper contains fiber from several sources—virgin pulp that we produce on-site, purchased virgin pulp and purchased fiber derived from post-consumer waste (PCW). To make kraft pulp, the first step in the process is to remove all of the bark from logs. After chipping the logs, we cook the wood chips in a large vessel under pressure with heat and chemicals. When the cooking is complete, the pulp is washed to separate the fiber from the lignin and cooking chemicals. The dissolved portion of the wood, including the lignin, and the cooking chemicals are called black liquor. The black liquor goes through a chemical recovery process, regenerating the cooking chemicals for use again and again. Both the black liquor and the bark get burned on-site to generate energy for the mill. These are both renewable energy sources that do not contribute to greenhouse gas emissions. Throughout these processes, there is very little waste — essentially everything from the tree either gets burned to create energy or converted to fiber for paper.
Sappi uses a chemical pulping process to produce our coated papers. During the chemical pulping process, lignin, the natural ‘glue' that holds the wood fibers together, is dissolved, freeing the wood fibers, which is why papers made with chemical pulp are called wood-free papers. We do this to ensure that the fibers we use are clean, undamaged and of the highest quality.
When the cooking process is complete, the pulp is still brown, so it has to be bleached before it can be used to make white paper. Historically, the paper industry used elemental chlorine bleaching processes that generated chlorinated compounds such as dioxins. Sappi uses only Elemental Chlorine Free (ECF) bleaching in its North American operations. ECF bleaching is considered by the EPA to be the best available control technology for minimizing the formation of chlorinated byproducts. Fiber derived from post-consumer waste is also processed chlorine free (PCF).
The whitened pulp is then combined with various additives to further define the final characteristics of each paper. Pigments such as calcium carbonate (chalk), are added for opacity, brightness and smoothness; dyes are added for shade control; optical brighteners are added for whiteness and sizing agents are added to control liquid penetration.
Once our pulp has been prepared to meet the exacting standards of a specific brand of Sappi paper, it moves onto the paper machine. The pulp mixture is evenly distributed on a high–speed mesh belt, called a wire, where water is removed and the fibers begin to bond and form a sheet of paper. Then it is transferred to the press section, where the paper is carried by an absorbent felt through a series of rolls that continue to remove more water. Afterwards, each side of the paper is passed over a series of steam heated drying cylinders. Finally, if the paper machine does not have online coating stations, the paper is wound into a large roll, called a reel, at the end of the machine. A base sheet of paper has now been manufactured.
To optimize the printing characteristics of our papers, special coatings are applied. The coatings consist of pigments (primarily calcium carbonate and clay) and binding agents (such as starch and latex) to uniformly cover the surface of the base paper.
Each side is coated and dried in sequence—with drying being performed by either infrared heat, hot air or drying cylinders. The number of coating applications used is dependent on how many layers and the unique ingredients that are required for each particular brand. The coating is applied to the base paper on a separate machine called a coater, or it is applied at coating stations that are part of the paper machine.
To optimize the smoothness or gloss of the coated paper, the coated surface is calendered. Calendering may be performed off–line on supercalenders or it may be performed online at the end of the papermachine. The paper passes through a series rolls that apply pressure and temperature to the paper. A combination of steel and soft rolls apply the desired finish to the surface of the paper.
Once our paper is packaged, it is sent to merchants and printers all across the country. From here it will be used to showcase the talents of the world's best graphic designers and printers and help tell the story of the world's finest brands and journalistic content. From car catalogs to glossy, internationally–published magazines, and elegant annual reports to sought–after photobooks, the possibilities of our paper are limited only by the imaginations of the people who use it.
All of Sappi's Fine Paper products can be recycled and we actively encourage designers and end-users to incorporate a "please recycle" logo or statement on their printed pieces whenever possible.
Ultimately, recycled fiber is best suited when used in the manufacture of paper products that are not used for high-quality graphic reproduction such as tissue, corrugated containers and egg cartons. Coated fine paper mills must buy the cleanest, highest quality de-inked fiber in order to maintain the quality that our customers demand, the yield (or percent recovery) of the recycled fiber is lower than recycled fiber used in lower quality paper grades.