Paper producers in Japan use waste paper for more than 60% of their raw material. That is, waste paper is used for almost 100% of the raw material in cardboard manufacturing and for approximately 35% of that in printer paper manufacturing. Pulp made from waste paper is known as recycled pulp. Compared with recycled pulp used in paperboard manufacturing, which is made by removing trash from cardboard waste paper, recycled pulp used in printing paper manufacturing is made from waste paper of items such as newspapers and magazines. The printing ink on the waste paper must be removed in a process that is known as de-inking.
To create recycled pulp from waste paper, waste paper is pulverized in water. If de-inking is required, a de-inking agent is used to separate and remove the ink from the pulp. Ink can be removed through a method known as flotation, in which the ink is first changed into fine particulates that are then dispersed. The ink particles are then adsorbed onto the surfaces of air bubbles in a foam that is separated from the pulp for efficient de-inking in a process . De-inked pulp is cleaned and bleached, if necessary, to become recycled pulp, which is known as de-inked pulp. This de-inked pulp, together with wood pulp, is recycled into various types of paper including newsprint paper, copier paper, and recycled tissue paper. In addition, the discharged foam that adsorbed the ink must be returned to a liquid state by foam breaking for the next stage of processing. An excellent de-inking agent must excel in foaming and also in returning to liquid state by foam breaking. Kao has contributed to the recycling of waste paper by developing a de-inking agent using derivatives of fatty alcohols and fatty acid through the Kao’s advanced surfactant technology, which has the excellent ability to remove inks from pulp. Combined with excellent ink adsorption to foam and agglutination characteristics of ink particle, excellent foam-breaking characteristics of REJECT.
Waste paper is a valuable resource for which even more effective utilization is required. Kao has much knowledge related to de-inking and is offering total technical support in improving customer value and the development of de-inking systems and new products for improving the yield rate of de-inked pulp.
From this perspective, Kao is striving to develop new chemical agents with excellent features to be used in waste paper recycling.