Paper towels are made just like any other form of paper, from either trees, wood chips, sawdust or recycled paper that is mixed with water to soak. The mixture is then mashed and stirred to form a mush of fibers called pulp, which eventually becomes the paper towels.
Bleach is added at the pulp stage to make white paper towels while a variety of dyes can be added to make colored towels. Brown can even be added to off-colored pulp to give it a natural look. The pulp is then sprayed onto screens to allow water to drain off. The remaining pulp fibers stick to each other on the screen to make a mat, which is squeezed through felt rollers to extract even more water.
To put the cardboard in the middle they rap the papertowel around it. but somtimes they dont use no cardboard so they wont have to throwit away.also beacause it is easy to do other then throwing it away