Increasing Bulk and Reducing Basis Weight in Current Paper and Paperboard Grades

Posted June 02, 2016 in Pulp and Paper Industry by Elizabeth Tischer

The production of paper and paperboard begins with the raw materials used. These can be either virgin plant material or recycled material such as other paper or plant material repurposed to meet the need of a rapidly growing industry that has specific demands as to the required paper grades and basis weight needed for the final product. Materials such as wood from a tree are transformed by mechanical and chemical methods to form different thicknesses and weights of paper designed for use as containers, packing materials, stationary, copying paper and a whole host of other products.

The basis weight of the product being produced is determined in part by the method used in production as well as the material being used. Certain species of plants have varying densities that effect the paper being manufactured. Hardwood, due to the short fibers, is hard to work with but is very effective in products that need to have a corrugated surface or those where an opaque surface is need for printing. Softwoods, such as spruce and pine, on the other hand, have longer fibers that lend themselves admirably to paperboards used for lining and in products where strength is used.

Recycled paper products often include materials from both hardwood and softwoods, as well as paper products of many varying thicknesses and basis weights. These are usually combined and the ink is not removed, which makes the resulting product a dull gray in color and uncertain in strength and weight.

The paper grades are designed to meet specific criteria as far as the end product is used for packaging, printing and writing. Thinner layers of paper are combined to make larger, stronger types of paperboard. The hardest part of the manufacturing processes is the fact that the expense and labor intensive methods used add to the cost and time in production. Research using different plant materials is underway to find better ways to increase bulk of paper products without overwhelming the industry costs. The machines used to make a specific type of paperboard are costly and over eighty percent of the industry is handled by a handful of manufacturers.

The use of superheated steam is one method to increase bulk in paper products. Others involve the application of filler ingredients when the material is being formed from wet pulpy basic material. Calcium carbonate is one of the filler materials used in the chemical methods of increasing bulk are being researched and tested as to their effects on the thickness of the end product. Paper products are being manufactured and used at an astonishing rate around the globe. In many countries, regulations as the to the type of materials used in the papermaking process have delayed the advancement of cutting edge techniques to reduce basis weight and standardize paper grades. As a result, there are differences between more advanced countries and those who are still refining the process. As technology changes and better methods are developed, the industry as a whole will improve. 

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