Filler Pigments Designed for Recyclability

Abstract

Printing and writing paper represents 30% by weight of all domestically made paper products. Today, however, less than 50% of that paper is recycled. The problem with waste paper from homes and offices is that it contains dyes, inks, and chemicals. If these additives are not removed properly—with no fiber degradation—the recycled paper will be of an inferior quality for writing and printing.Recycling, however, is the future. In 1990, 28.9 million tons of paper were collected for recycling, representing a collection rate of 33.5%. By the year 1995, the collection rate goal is 40%, with favorable economics supporting increased utilization of recovered paper. For example, a ton of paper made from 100% waste paper saves 17 trees, 4,100 kWh of energy (approximately 6 months of power used by the average home), 7,000 gallons of water, 60 pounds of air-polluting effluents, and 3 cubic yards of landfill.Two of the issues facing recycled fiber utilization are the cost and visual quality of the final sheet. Paper brightness, opacity, and printability are the industry's biggest concerns when comparing the quality of recycled fibers to that of virgin fibers. The common approach to increasing brightness is to add a white filler pigment such as precipitated calcium carbonate (PCC), ground limestone, clay, and/or titanium dioxide. Chemical optical brighteners have also been used, but their use will decline as consumers ask what impact the brightening chemicals have on the environment.