Paper core manufacturers make paper cores to suit many different needs. Paper cores and paper tubes are used by businesses for many consumer products. They can be used as fill to protect the contents of shipping containers, and sometimes they are used as the shipping containers themselves.
How Paper Core Manufacturers Make Paper Cores
A paper core is made from layers of rolled paper called plies. Manufacturers glue piles together to provide strength and structure.
Most paper cores have only two components: the paper that forms the core and the adhesives that hold it together. Kraft paper is the most common paper used to manufacture cores. Manufacturers can use other materials for specific applications, and they use waterproof or water-resistant cardboard when the cores may be used for a product that will get wet. Recycled paper and fiberboard are also common materials.
The innermost ply in a paper core is called the liner, and the outermost is called the wrap. Some applications call for alternative materials in the liner or the wrap, and metal foils or plastic films are common materials for these applications.
The adhesive used in the manufacturing process is another key component that manufacturers can change to alter the properties of the finished paper core. The manufacturer can use traditional and modern glues for this process, but common alternatives include dextrin-based adhesives derived from plant starches such as tapioca or maize. Additives such as sodium hydroxide and borax can also change the properties of the bond to suit the end goal needs.
Preparing the Paper
Manufacturers make paper cores from narrow rolls of paper. They layer this paper upon itself to form the plies that give the core strength and structure.
Manufacturers cut wide rolls of paper into narrow strips. They then feed the trimmed paper through a tank that contains the adhesive. The adhesive permeates the paper, preparing it for the next step. The water content of the adhesive is essential as too much water will make the core take longer to cure properly.
Shaping the Paper Core
Manufacturers coil the paper around a metal pole called a mandrel. The manufacturer chooses the mandrel’s diameter to meet their client’s needs. The mandrel’s diameter determines the inner diameter of the paper core. Mandrel shape is also essential. Most mandrels have a circular cross-section, but mandrels with other cross-sections are used to change the shape of the paper core. Triangular, square, and hexagonal cross-sections are some of the more common alternatives.
Controlling Ply Count
Manufacturers control the ply count of the core by adjusting the angle at which they feed the paper into the machine. Feeding the paper into the core-forming machine at a narrow angle allows the paper to move more quickly along the mandrel. Narrow angles create thinner cores. Thinner cores are ideal for consumer paper products like household paper towel rolls and paper straws.
Other products may require a thicker core for increased strength and rigidity. Manufacturers make thicker cores by using wider angles, allowing the paper to layer over itself more often. More plies make sturdier cores. Cores like this are ideal for plastic film, spools, and concrete forms.
Occasionally, manufacturers feed the paper into the machine perpendicular to the mandrel. These cores are called convolute wound paper tubes. Convolute wound cores are ideal for applications where crush resistance and dynamic strength are important considerations.
Finishing the Core
The paper core moves along the mandrel while the paper coils around it. This motion creates friction which adds heat to the system. Manufacturers use this heat to activate the adhesives and reduce the time it takes for the core to cure.
When the core reaches the desired length, a blade cuts the tube. The blade moves along the mandrel with the paper core to make an even cut. The completed core is now ready to be distributed.
The Right Paper Core for Your Business
Paper cores and tubes are versatile and cost-effective solutions for many business and industrial needs. Paper core manufacturers can achieve a variety of results by controlling a few simple variables. Whether your company manufactures consumer goods or needs to get those goods to a certain destination, paper cores may be your solution.