Studies on the Neutral Beater Sizing in the Process of Paper Manufacturing

Abstract

It has been a most common practice at the paper mills that the method called the acidic fixation in lower PH (PH 4-4.5) was applied to size the paper, however, due to the excess of aluminum sulphate would decompose alkaline earth filler such as calcium and magnesium carbonates and destroys its sizing effect.After a long carefull studies and experiments were carried out we have finally succeeded in produce the neutral sizing agent which produced excellent sizing effect even in the nearly neutrality (near to PH 7.0).For the example, we mixed with about 10-40% of precipitated calcium carbonate into the pulp in the beater adding with the neutral sizing of about 1-4% and the aluminum sulphate of 1-3%, then we are able to observe the perfect sizing effect on the tissues and printing papers. In other words, the test result of Stoickigt method was indicated about 30-50 seconds (60g/m2).Also, it is known to manufat cure the high grade none-filled paper (such as writing, bond, name-card paper etc.) made with the process called the acidic sizings, in this connection the required amount of aluminum sulphate is to be limited approximately between 1/4-1/5 as to compare with previous method. Assuming as to obtain size of 2 per cent it only required between 0.4-0.5 percent of aluminum sulphate are sufficient.Many tests carried by actual operation at the various paper mills, we are convinced more from those data and results, this is more effective medium for paper sizing than any other sizing agents. In this field and many Japanese paper mills are to start using and adopting the neutral sizing for the purpose, therefore we are prepared to state the merit and advantages of this material as follows.1) In the past a most important filler for the papers are those of various clays, however to obtain with the whiteness (above 95 %) and perfect filling effect many paper mills are able to use of those calcium carbonate and magnesium carbonate as the filler from now on.We recommend to use it for high grade tissue paper such as air mail and india paper which are required more translucent. It also can be used for a suitable common writing paper making because resistance against the Perker's fountain ink which consist of high degree of PH2) In the manufacturing Japaness paper by the cylinder paper machine, this neutral sizing agent will give much satisfaction for the reason of it's nature which will not destroy the fibre dispersing ability of mucilages (abelmoschus manihot) which will be able to adjust the uniform suspension of long fibres to coagulation in the acidic reaction of rosin and aluminum sulphate sizing.3) On account of the neutral nature in sizing, the durability and preservation of paper could be maintained and gain many other benefits by using it.4) It is known fact that a close relationship exists between the rate of dryness of paper and or printing ink and in this connection the expert on this subject recently recommended of the neutral slightly alkaline fixation for the sizing. (Ref. A. Voet : Ink and Paper, Part II pp 193 5) 5) This neutral sizing agent is a quite effective and ideal method and proceed with the method of neutral size, it will not only save a larger amount of aluminum sulphate but also save a big amount of fluorescent dye which intended to improve the whiteness of papers thus by using it themanufacturing cost will be sufficiently reduced. (In the case of the size produced under the acid condition will have a tendency of change of the red shade) 6) Due to the neutral nature of itself, this will definitely help to reduce the erosive action on the machine wire thus prolong the life of the wire.The neutral size is a sort of high-free rosin soap which is produced under a special saponification, process and it was prevented the coagulation of rosin particles by using the protective colloids.