Mill rolls are one of the most important and yet least understood parts of a paper mill. They’re essential for turning raw wood into paper pulp, but they also play an integral role in producing finished products like toilet tissue, napkins, and paper towels.
Mill rolls have many different applications throughout a production process that can be divided into two major processes: The preparation stage and the finishing stage. In this article, we’ll explore three ways mill rolls are used during these stages to produce some common household items you might find in your bathroom or kitchen right now.
1) They Make Paper
This is the most obvious and oldest application of mill rolls. Many people don’t realize that most paper products are made using recycled paper with a high percentage of post-consumer waste (PCW). This means that almost all toilet tissue, napkins, and even paper towels are made with recycled paper. To make this recycled paper, a large percentage of the wood pulp is used to create other products or even burned to create electricity.
The basic process for creating paper on a roll mill uses cellulase that breaks down the cellulose fibers in wood into glucose molecules that can be filtered out from all the contaminants and then dissolved into water. This paper slurry is then mixed with water and passed between a series of rotating cylinders. The pressure created by the cylinders causes the mixture to push through tiny holes in the form of a continuous sheet which is partially dried and finally wound onto large rolls.
2) They Make Tissue Paper
After that process, tissue paper is made by taking these large rolls of paper and mechanically tearing it into a smaller sheet by passing it through sets of high tension metal wires. These machines are referred to as wire breakers.
Once the sheet is finally torn down from the roll, it’s sprayed with a thin layer of adhesive and then rolled onto another spool in a giant machine known as a rewinder. This final machine uses thousands of pounds of pressure to squeeze the adhesive through the paper and create a sheet-ready sheet packaging.
There are many different types of tissue products on the market, but they all use this simple process in some way or another as it’s the most cost-effective method available today.
3) They Make Napkins
The final process we’ll look at is how napkins are made. Unlike tissue paper, they don’t use a wire breaker to tear the sheet from the roll. Instead, the roll of toilet tissue is mechanically cut into specific sizes using shear knives. Then holes are punched into these sheets to create a “linting effect,” which causes small particles from the wood pulp to stick onto the paper. This was originally done by hand, but today most mills have specialized machines with rotating drums that use pressure and centrifugal force to punch these tiny holes into the paper.
Smaller napkins are then made in a similar process using the same large rolls of paper. The only difference is that they’re cut into smaller pieces using a slitter rewinder machine thatches sheets into more manageable sizes. In addition to these three uses, mill rolls are also used to produce the scotch tape, waxed paper, and even corrugated boxes that line the inside of cardboard boxes.