Acid Resistant Calcium Carbonate for Sizing in Paper Manufacturing

摘要

The salient features of the process patented for production of acid resistant calcium carbonate, suitable to be used in acid sizing of paper manufacturing are given. Ground calcium carbonate (GCC) has been chemical treated and used at pH of 4.5 in alum- rosin sizing of bamboo-hard wood bleached pulp. The acid resistance property of the new product (SCC) has been established by titration against alum and the water repellency of the hand sheet made with the products from measurement of cobb values till circulations to 70 times in the laboratory . The optical, strength and printability properties of hand sheet loaded with the surface coated calcium carbonate have been determined and compared with that of uncoated PCC, GCC and talc. The surface coated product (SCC-Ⅰ) has higher brightness (by 5 per cent EI) than that of talc with improvement in retention and printability properties.