JPS616397A - Enhancement of filler yield in neutral papermaking - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for improving filler retention in neutral paper making in the paper industry.

(Prior art) To manufacture paper, especially printing paper, conventionally, clay, kaolin, talc, etc. are added as fillers, a ronone-based sizing agent is added, and sulfuric acid/gundo is added to this to adjust the pH on the acidic side. 4.
It was made into paper with a size of about 5.

The purpose of adding fillers is to improve the printing effect and increase opacity, but the low pH reduces the durability of the product, and when stored for a long time, the paper deteriorates and becomes colored, resulting in extreme In some cases, it had the disadvantage that it would fall apart into pieces.

Furthermore, acidic papermaking has the disadvantage that the equipment is severely corroded, so it has been desirable to make paper in neutral or alkaline conditions.

The reason why sulfate band is used to make it acidic is that sulfate band is absolutely necessary to fix the Ronon sizing agent to paper, and it was not possible to replace it with other fixing agents such as cationic polymers. . However, in recent years, neutral sizing agents such as alkyl ketene dimers have been developed, and paper manufacturing methods are shifting to neutral papermaking, and more than 50% of Yorotsu and P papermaking processes have already converted to neutral papermaking.

The advantages of carbonation are that in addition to improving the durability of the paper and reducing corrosion of equipment, it also allows the use of calcium carbonate as a filler.

Talc, kaolin, used as fillers in acid paper making,
Domestically produced products are inferior both in quantity and quality, and currently most of them rely on imports. However, in the case of neutral papermaking, calcium carbonate, which is abundantly available in Japan, can be used, which is advantageous in terms of cost.

The biggest problem in neutral papermaking is improving the yield of carbonate cal/rum filler. Talc and kaolin, which are used as fillers in acidic papermaking, have very strongly negatively charged surfaces, so
While cationic polymers can form flocs well and improve yield, calcium carbonate has a weak surface charge, and some are positively charged.
Aggregation by polymer is extremely weak.

Conventionally, most of the retention aids used as retention aids in acidic papermaking were Mannich acrylamide, and
Since it is a class cation, it loses its effectiveness at pH 8.5 and cannot be used.

Therefore, this tertiary cation is
If graded, it is effective at pH 8.5, but this polymer decomposes in alkaline conditions and generates an extremely unpleasant amine odor, so it cannot be used, so CH3CH3 CH=C, -C-0-CH-N+ A copolymer of -CHX- and 1]10CH3 acrylamide has been used, but this polymer does not have a sufficient retention effect and requires a fairly high degree of polymerization to be effective.

Moreover, it also has the disadvantage of deteriorating reactor water properties.゛Since most of the calcium carbonate produced in Sudan is positively charged, anionic polymers have also been used, but these polymers are surprisingly less effective and are only effective if they are made with an extremely high degree of polymerization. This causes problems with workability and soiling of tools, and the reactor water quality becomes extremely poor.

(Objective of the Invention) The object of the present invention is to provide a method for improving the yield in neutral paper making, which eliminates the above-mentioned drawbacks.

(Problems to be Solved by the Invention) That is, the important point of the present invention is to find a polymer that exhibits a high yield effect with an extremely low amount of cations and a low degree of polymerization, and to improve reactor water properties.

(Means for Solving the Problems) The present invention is intended to solve the problems as described above.
indicates an anion)11. The monomer content is 3
~Kasumi Morti, (B) The retention of filler in neutral paper making is improved by adding a copolymer containing 40 to 97 moles of acrylamide to the paper stock.

(Effect) The addition of this polymer shows a revolutionary effect as a retention improver in neutral papermaking, and shows a high retention effect with an extremely low amount of cations.However, in the actual papermaking process, various substances are used. Basically, a good effect is obtained with a cation amount of 3 molar ratio, but in reality, a cation amount of 5 molar ratio or more is desirable.

A high amount of cations does not have a significant effect,
Since the cost increases, the limit seems to be (a) about mol%. The selection of the amount of cations is determined by the nature of the stock to be applied. For paper stock that consumes a large amount of cations, it is necessary to increase the degree of cation.

, l The degree of polymerization is mainly determined by paper-making conditions. If the degree of polymerization is too high under conditions of low shearing force, the formation will deteriorate, while if the degree of polymerization is too low in a paper machine operating at high speed and high shearing force, a sufficient yield effect cannot be obtained.

Another feature of the present invention is that it has the effect of improving reactor water properties. In the case of neutral papermaking, since p)I is 8.5, which is on the alkaline side, the pulp fibers swell and the furnace water resistance becomes worse than in the case of acidic papermaking. ,.

Therefore, the retention agent must also have the effect of improving the aqueous properties. In this respect, the polymer of the present invention can be said to be an extremely excellent neutral papermaking retention aid because it also has the effect of improving furnace water properties.

(Implementation fli) Disintegrate and beat the LBKP sheet to O8F 350 r
n! Make iJ' Ruzo slurry, add calcium carbonate to a content of 30g, and add cationic starch.
0.5% was added to Glube to make paper stock. The yield effect was determined using a single dynamic jar. The results of adding 0.3 g of an alkyl ketene dimer cation sizing agent and 0.02% of a retention agent to the above paper stock were as shown in the following table.

(revised)

Claims (1)

[Claims] (A) General formula ▲ Numerical formula, chemical formula, table, etc. ▼ (In the formula, R_1 and R_2 are alkyl groups having 1 to 2 carbon atoms,
A copolymer containing 3 to 60 mol% of the monomer (X^- indicates an anion) and 40 to 97 mol% of (B) acrylamide is added to the paper stock. A method for improving filler retention in neutral papermaking.