CHEMICALS USED IN PULP &PAPER MANUFACTURING AND COATING. Silicate of Magnesia.
Common Name. Two major chemical pulping processes are cur- rently in commercial use: 1) kraft (sulfate) pulping, and 2) sulfite pulping. Chemical Name. Coating binders – Added to provide paper with the surface that will increase water retention, and thus make paper more durable. Used For. Agalite or Talc. While there are about 3000 or so different types of chemicals which "can be used" in papermaking, in practice only about 200 individual chemicals are typically used, each satisfying a specific need. MgO-32%, SiO 2-42%. Chemical processes may yield only half the fiber that can be recovered by the use of mechanical pulping techniques. Paper strength and durability is gained at the expense of fiber yield. Under these highly basic conditions, the negatively charged sulfide ions react with the lignin polymer chains to break them down … Paper makers must remove the lignin from the wood pulp. Chemical Formula. Most commonly used agents are dextrin, oxidized starch, styrene butadiene latex, and styrene acrylic.
To accomplish this, one of the main chemical reactions used in industry is the Kraft process, in which wood chips are combined with a mixture of sodium hydroxide and sodium sulfide in water at high temperature and pressure. The steps in the process are as follows: (1) a suspension of cellulosic fibre is prepared by beating it in water so that the fibres are thoroughly separated and saturated with water; (2) the paper stock is filtered on a woven screen to form a matted sheet of fibre; (3) the wet sheet is pressed and compacted to squeeze out a large proportion of water; (4) the remaining water is removed by evaporation; and (5) … Mineral Fillers – They enhance internal structure of the paper, most commonly used substances are calcium carbonate and china clay.