JPS616398A - Enhancement of filler yield in papermaking process - 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] (Industrial application field) The present invention is a method for improving filler retention in a paper manufacturing process.

(Conventional technology) Conventionally, when manufacturing printing paper, wood/Prusso, clay,
Paper is generally made by adding inorganic fillers such as talc and kaolin. This is for the purpose of improving the opacity of the product, making the surface smooth, and improving the transfer of printing ink. However, since these fillers are fine powders, if DOL is added alone, they hardly remain in the paper, and most of them pass through the paper-making wire and flow out into the white water. In the production of general printing paper, Ninon-Size, which is a modified product of Lono 7, is added as a rising agent to impart water resistance to the paper. Since this Ronone sizing agent is anionic, sulfuric acid is added to fix it to adjust the pH to 4.5.

- Although the filler is also aggregated by sulfuric acid band, it is hardly possible to expect a higher yield with this. Therefore, a method is generally practiced in which a retention improver is used to improve the filler retention direction -L. In this case, polyacrylamide cationized by Mannich reaction is most often used as the L agent for yield. It is believed that the -7-ninohylated polyacrylamide aggregates both the Parzo fibers and the filler to form a floc, thereby preventing them from flowing out from the wire mesh. Although it has been quite effective, its effectiveness is gradually decreasing due to the increase in the use of recycled water and the decline in the quality of raw materials and raw materials. Therefore, there has been a demand for the development of highly effective retention aids.

(Objective of the invention) Under the above circumstances, the present invention has a low cationization rate and excellent cohesive force, greatly improves the freeness of the paper stock, reduces the water content by pressing in a press, and reduces white water. The purpose is to maintain considerable effectiveness even under conditions of high usage rate, increase the yield of filler and morph 0, and improve wetability.

(Problems to be Solved by the Invention) In order to achieve the above object, a special polymer is added during the paper manufacturing process to improve the retention of filler/morph and increase the F water content.

(Means to solve the problem) What is the special polymer that achieves the above purpose (in the formula R
1+ R2 is an alkyl group having 1 to 2 carbon atoms, x-H anion) The content of the monomer represented by (a) molti is 3 to (a) molti, (B) the content of acrylamide is 40 to 97 molti It is a copolymer with a high molecular weight, and by adding it to the paper stock, it is intended to improve the filler retention in the papermaking process.

(Effect) This copolymer has excellent cohesive strength and greatly improves the freeness of the paper stock, as well as reduces the water content when squeezed in a press.Moreover, in Mannich polyacrylamide, a high degree of cation substitution is an important step. While required as a distillation improver and a reactor water properties improver, the polymer of the present invention can provide excellent effects with a low cationization rate.

Furthermore, when the rate of old white water is increased and the impurities in the system increase dramatically, the effectiveness of Mannich polymers is drastically reduced, sometimes to the point where they are almost ineffective. Polymers retain fairly good effectiveness even under such adverse conditions. This is an extremely important property when actually used in paper mills, and there is currently no example of a polymer that is effective under such adverse conditions.

The cationization rate of the polymer according to the present invention can be freely changed depending on the purpose and various conditions. A degree of cationization of at least 3 molty is sufficient, but a degree of cationization of 5 molty or more is somewhat unstable because of the accumulation of anionic substances in the papermaking stock due to circulating water. Furthermore, increasing the degree of cationization is not preferable because it increases the product cost, although the improvement in effectiveness is not significant. 60 molar ratio is considered to be the limit.

The degree of polymerization of the polymer according to the invention must be varied depending on the properties of the paper stock, papermaking conditions, etc.

Chemical products such as BKP? In factories where 100% Luso is used and the papermaking speed is slow, the shearing force is weak and the formation is likely to deteriorate due to agglomeration, so the degree of polymerization needs to be low. 1. In the case of large-scale high-speed paper machines, strong shearing force is applied, so it is difficult to achieve a sufficient effect with a low degree of polymerization, and in the case of paperboard etc. with a large amount of foreign substances, the coagulation effect is reduced and the degree of polymerization is high. Otherwise, it will not be effective.

The polymer according to the present invention not only improves the yield of filler, .gluzo, but also improves the θ5
It also has the effect of improving water quality. Therefore, extremely effective effects can be expected, especially in the production of cardboard.

(Example) Dry LBKP notes were disintegrated and beaten to produce csn3.
50 rnl of .P luzo slurry was prepared. To this, an amount of papermaking talc was added to give a content of 30%, and 3% sulfuric acid was added to the solution to adjust the pH to 4.5.

Various retention aids were added to this paper stock, and the yield was measured using the Guinamitsukunoya method. The amount of the retention aid added was 0.01% based on the amount of lug, and the results are shown in Table 1.

Table 1 (Note) Invention product A Cation 3 mol% R,, R2 are methyl groups B 5 mol% R1, R2
is a methyl group〃 C〃 15 mol% RIIR2 is a methyl group〃 D 〃 35 mol% R1+R
2 is an ethyl group 77 E II 60 moles R1+R2 is an ethyl group Commercial product A Mannich polymer, cation 40 moles B
Cation (a) Molch Commercial product C Mannich polymer, Cation blade Molch.

Example 2 The following experiment was conducted to reproduce the papermaking conditions at a medium-quality paper manufacturing site. LBKP 40%, (1!SP 30chi,
GP 20% of talc as a filler, 3 t of sizing agent, and 4 t of sulfuric acid are added to the pulp 0 paper stock with a proportion of 30%, and the mixture is filtered through a wire mesh made of Inmetsu Yu to make white water, and then the above-mentioned pulp 0 in this white water and add each chemical.

This operation was repeated twice to create an artificial field sample.

The yield of this paper stock was measured using the same Guinami Sokunoya method as in Example 1, and the results are shown in Table 2.

Table 2 Although an improvement in the total yield was obtained, in particular, the filler yield was observed to be in the direction of -F from the cutting edge to the cutting edge.

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,
＾- indicates an anion) monomer content is 3
60 mol%, and (B) a method for improving filler retention in a papermaking process by adding to paper stock a copolymer having an acrylamide content of 40 to 97 mol%.