How is Tissue Made?
Tissue paper products may seem simple, but manufacturing these specialty papers requires advanced science and technology. The first step in the tissue making process is to make pulp. The pulp can be made from either virgin fiber, which is wood chips, or from recycled paper products.
Wood chips (virgin fiber) are cooked using a chemical process is essentially a pressure cooker known as a digester. The wood fiber is separated into cellulose fibers, lignin (the wood glue that holds the tree together) and other substances such as sugars. Cellulose is an essential building block in the cell walls of trees and plants, helping to make them strong. The pulp is then washed to clean it and separate it from other substances such as lignin. After the pulp is washed, it is screened for further cleaning.
For mills using recycled materials, the pulp is made by mixing the recycled materials with water in what resembles a large blender called a pulper. In the pulper, the pulp is separated to create individual fibers in a slurry. From there, the pulp is washed and screened for further cleaning.
Screening the pulp removes oversized and unwanted chunks or pieces from the slurry, leaving the best fibers for tissue products. The cleaning process further removes any unwanted particles and debris like any dirt or dust.
The pulp then goes through a series of rollers where the water is squeezed and evaporated out, helping to dry out the pulp. Though lignin is removed during the washing process, some lignin remains together with the fiber and at this stage, it has a natural brown color. At this stage, the pulp is bleached, further separating the cellulose fibers from the lignin, increasing fiber strength while creating a bright white color.
After the pulp is bleached, it needs to be formed into a sheet by the paper machine. At the wet end of the paper machine, the pulp flows onto a moving endless belt with a screen to filter out water and form a web. Further down the line, in the press section, the pulp, which looks like a white sheet, goes through several presses to further remove excess water. At this point, the web of material still must shed water, so it passes into a dryer. The dryer is a large cylinder and uses steam to dry the pulp. The wet web of pulp is pressed against the cylinder tightly to dry it through evaporation, providing a consistent thickness prior to the paper being processed into a giant roll.
At this stage, many tissue papers are further processed or converted for consumer use. For example, tissue may be further embossed or creped. Embossing rolls create a textured design pattern onto the tissue like the dots and swirls on your paper towels or toilet tissue. Creping enhances the overall thickness, making it softer, and adding the stretch properties to the paper.
After the paper is creped, it is sent to a converting machine that turns the paper sheet into the tissue products you recognize. Converting machines can turn the paper into multiple plays, fold tissues and napkins, or otherwise transform large sheets or rolls into the final packaged configuration.