Calendar gum is part of your everyday life, even if you may not know what it is. Calendered rubber is made by drawing rubber through the small space between two rollers. The extreme pressure forms the rubber into sheets. Calendered rubber can also be made with steel or fabric, creating a composite material.
To see how calendered rubber affects your life, take off your shoes and turn them inside out. The outsole with its rubber profile is most likely made of calendered rubber. When manufacturing shoes, outsoles are made in whole strips. The rubber is first passed through smooth rollers, which smooth it out so it can be used as an outsole, and then through a textured roller, which shapes the tread design and any manufacturer’s marks. After the calendering process is complete, the outsoles are cut from the rubber sheets – like cutting cookies from freshly rolled dough.
Another way calendered rubber improves your life is in the provision of transportation: your car’s tires are made of calendered rubber. You may not know this, but your tires have steel belts in the rubber that give them their shape and strength. The steel strips get into the rubber through calendering: The steel strips are fed through the rollers with the rubber on both sides. The rubber bonds to the steel due to the exceptional pressure that the rollers exert on the steel and rubber.
Calendered rubber can contain materials other than steel. For example, calendered rubber is sometimes made with fabric inside. As in tire manufacture, the rubber is placed on both sides of the fabric and the three plies are fed through the rollers together. As with tire rubber, the extreme pressure during calendering causes the rubber to bond to the fabric.
Even your heroes rely on calendered rubber to give them their “superpowers” – calendered rubber is used to make the strong, fire-resistant boots that firefighters wear. As you can see, calendar gum affects your life in many ways, whether you know it or not.
The calendering process is used to make things other than calendered rubber. For example, paper is calendered to give it a smooth surface. The coating used on the paper and the degree of calendering that the paper undergoes determine whether the end product has a matte or gloss appearance. For a coarser look, the paper can be left non-calendrical.