JPS6163796A - Papermaking method - 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 Field of Application) The present invention relates to a method for producing paper containing filler with an ash content of 40 inches or more.

BACKGROUND OF THE INVENTION In the production of printing paper, fillers are essential to increase the opacity of the paper. Recently, there has also been a demand for highly opaque paper as base paper for various types of processing.

Traditionally, kaolin, Merck, calcium carbonate, etc. have been used as fillers. However, as the amount of filler added increases, the strength of the paper decreases and the fixation rate of the filler to the paper also decreases, so there is a limit to the amount of filler that can be added.

In general, the amount of ash that can be contained in paper is 20% as the ash content of paper.
% or less is normal.

Fillers have a negative surface charge in water, similar to that of pulp, so when they coexist, they electrically repel each other and fixation is usually not very good.

Until now, the use of anionic polymeric substances or cationic polymeric substances or the adjustment of zeta potential have been proposed as internal additives, but in either case, the aim is to increase paper strength or filler yield. However, none of these methods have been applied to paper containing filler with an ash content of 40 inches or more and have been effective.

For example, JP-A-55-12868 discloses a method in which a cationizing agent is added to the pulp to raise the zeta potential to -10 to +5 mV, and then a cationic internal additive is added, but this method uses less cationizing agent. In other words, when the zeta potential is negative (no reversal of the zeta potential), there is poor fixing, and when there is a large amount of cationizing agent, fixing occurs at this point, but furthermore, when the cationic internal additive is Since the zeta potential of the system changes significantly upon addition, there is a drawback that electrical repulsion again causes poor fixing and poor formation due to pulp aggregation. Also, JP-A-5
No. 6-123498 relates to a method of making paper by adding a cationic polymer substance to pulp, then adding calcium carbonate, and then adding an anionic polymer substance having a carboxyl group. The paper has a filler addition rate of 20 fibers to the pulp and an ash content of 10 to 12 fibers, which is incomparably lower than the 0.40% or more ash of the present invention, and a cationic polymer substance, The amount of anionic polymer substance added is 0.01 to 0.2 yen and 0.05 yen, respectively.
The purpose and technical idea of the present invention are completely different from those of the present invention in that a small amount of ~0.51 makes it impossible to reverse the zeta potential of the system as in the present invention.

Furthermore, JP-A-56-159397 describes a method in which a cationic polymer substance and an anionic polymer substance are used in combination, sulfuric acid band is added, and the pulp is adsorbed in an acidic system, but the purpose is to improve the dry paper strength of paper. This has nothing to do with the inclusion of fillers.

The recent Japanese Patent Application Laid-Open No. 59-106598 relates to a method of papermaking by adding an anionic polymer to pulp and then adding a high molecular weight cationic polymer. Even if a neutral polymer is added, the zeta potential only shifts significantly to the negative side and does not have a good effect on fixing.

Furthermore, when a cationic polymer is added, when the amount is small, the zeta potential remains on the negative side, so fixing is not sufficient; when the amount is large, the zeta potential reverses to positive, and fixing occurs, but However, it has the disadvantage of causing problems on the paper making surface such as poor formation and staining of paper making tools.

In addition, although the purpose of the invention in this publication is to improve reactor water properties and improve the yield of fillers and fine fibers, there is no specific description of improving the yield of fillers, which is irrelevant to the present invention. It is something.

As mentioned above, various methods have been proposed for adding cationic polymeric substances and anionic polymeric substances to pulp, but none of them do not positively reverse the charge of the system.
2~-101! Usually, the filler is added in such a way that the filler becomes V, and the fixation of the filler cannot be achieved sufficiently.

For example, the amount of cationic polymer substance added is 0.1 to pulp.
~1% is common, reducing the zeta potential of the system to -2~'i'l
It was common to stop at OmV.

If this was reversed to the positive side, there were disadvantages such as a decrease in reactor water properties during paper making and a deterioration of paper formation.

(Means for solving the problem) On the other hand, the present invention adds a cationic polymer substance in a larger amount than the usual amount to a pulp suspension containing a large amount of filler to raise the zeta potential of the system to +5 to +10 mV. After inverting the charge to a positive charge and sufficiently fixing the filler, an anionic polymer substance is added to raise the data potential of the system to -5 to -10 mV.
This is intended to improve the fixation of the filler as well as improve the reactor water resistance and paper formation.
Even if a large amount of filler is blended, such as 0% or more, good paper-making properties and paper properties can be maintained.

As is clear from the examples, the amount of the cationic polymer substance added initially to fix the filler reaches 2 to 6 times the pulp, which is compared to the normally added amount of 0.1 to 1. This idea is unprecedented in the prior art.

The fillers used in the present invention may be those used in ordinary paper manufacturing, such as kaolin (clay), Merck, calcium carbonate, etc., which are added to have an ash content of 40% or more.

Of course, when calcium carbonate is used, paper is made using the neutral papermaking method.

In addition, as cationic polymer substances, cationically modified starch (tertiary or quaternary amide modified), cationically modified polyacrylamide (Mannich modified product or Hoffmann modified product), polyamide, polyacrylic/epichlorohydrin resin is used, and the zeta-based Apply until the potential is +5 to +10 mV.

The anionic polymer substance is generally anion-modified polyacrylamide, but starch, polyvinyl alcohol, and various other monomers having carboxyz groups, sulfone groups, etc., such as acrylic acid, methacrylic acid, maleic acid, There are homopolymers of their anhydrides, fumaric acid, itaconic acid, vinyl sulfo/acids or their salts or copolymers of these monomers with other monomers copolymerizable with them. Other seven polymers to be copolymerized include ethylene, butylene, diisobutylene, decene, dodecene, acrylonitrile, methyl acrylate, ethyl acrylate,
Methyl methacrylate, ethyl methacrylate, styrene,
Examples include vinyl acetate. These anionic polymer substances are added until the charge of the system reaches 15 to nomV.

In the paper manufacturing method of the present invention, in addition to adding the above-mentioned fillers, cationic polymeric substances, and anionic polymeric substances, sizing agents, coloring agents, wet paper strength agents, and furnace water properties improvers used for ordinary paper are added. These internal additives can be used in appropriate combinations depending on the purpose of the paper.

Note that the zeta potential in the present invention is 60% in the pulp suspension.
The mesh sieve fraction is the value measured by microelectrophoresis for the fraction that passed through the sieve.

(Example) Example 1, Comparative Example I A pulp suspension consisting of NBKP50s and LBKP50% was heated at a concentration of 10 cm to a water temperature (same as below the Canadian standard water temperature) of 3
Beating was performed in a PFr mill until it became 00-. The zeta potential of the pulp suspension diluted to 3 concentrations is -1
It was 9mV.

Next, 1 liter of alkyl ketene dimer (Varcon W manufactured by Dainippon Ink Chemical Co., Ltd.) was added as a sizing agent to the pulp, and 140% of heavy calcium carbonate was added to the pulp as a filler. Nippon Starch Chemical & 3 tapioca starch) was added. The amount of cationic starch added at this time was 6 times the amount of pulp.

Next, the pulp suspension was sufficiently stirred to fix the filler, and then anion-modified polyacrylamide (Polystron 117 manufactured by Arayo Kagaku Kogyo Co., Ltd.) was used until the zeta potential reached 15+ aV.
) was added. The amount added at the time of addition was 0.8% based on the pulp.

Using this raw material, handmade paper with an absolute dry equivalent weight of 502 sheets was prepared using a TAPPI handmade sheet machine. For comparison, the above-mentioned pulp mixture was beaten by the same method, and the sizing agent was 0.5 g of alkyl ketene die-r-, the filler was 160% of ground calcium carbonate, and the cationic starch was O, S.
I added a few.

The zeta potential at this time was -6 mV. Using this raw material, handmade paper was prepared in the same manner as in Example 1.

The filler yield and paper quality test results for the obtained handmade paper are shown in Table 1.

Table 1 Example 2, Comparative Example 2 A pulp suspension consisting of 90% NBKPI and LBKP was processed using a disc refiner.
QOdK was beaten and diluted to a concentration of 2 parts. To this, talc to pulp is 94% as a filler, and rosin size (Size Pine E50 manufactured by Arayo Kagaku Kogyo Co., Ltd.) to pulp is 0.7% as a sizing agent.
3% of sulfuric acid hand pulp was added, and to this was added cationically modified starch and pioca starch as a cationic polymer substance until the potential was +10 mV to invert the charge to positive. The amount added at this time was 5 parts to the pulp. Next, after the chemicals and fillers were sufficiently fixed on the pulp, anion-modified polyacrylamide as an anionic polymer substance was added until the zeta potential reached -7 mV. The amount added at this time was 0.5 ratio to the pulp.

Using this raw material, handsheet paper with an absolute dry equivalent weight of 70 fed was prepared using a TAPPI handsheet machine.

For comparison, a pulp suspension prepared using the same pulp was mixed with Merck 45% as a filler and rosin size 0.5911 as a sizing agent. Anion-modified polyacrylamide as an anionic polymer substance was added to 4% of sulfuric acid band to 0.0% of pulp.
Added 5 parts. The zeta potential after addition was -6 mV. Handmade paper was prepared in the same manner as in Example 2 using this raw material.

Filler yield and paper quality test results for the obtained handmade paper t-
It is shown in Table 12.

Table 2 Example 3, Comparative Example 3 Pulp consisting of 30% NBKP and 70% LBKP was
Beating was performed using an APPI beater to a furnace water level of 100.

To this pulp suspension, heavy calcium carbonate (130% based on the pulp) as a filler, alkyl ketene dimer 196% as a sizing agent, and Mannich modified polyacrylamide (HRC-882 manufactured by Showa Denko) as a cationic polymer substance were added. and increase the zeta potential of the system to +7WL.
Adjusted to V. The amount added at this time was 2 parts to the pulp.

Next, after the chemicals and waste materials were sufficiently fixed on the pulp, polyvinyl alcohol (Poval 117, manufactured by Kuraray Co., Ltd.) was added as an anionic polymer substance until the zeta potential reached -5 mV. The amount added at this time was 1 inch per pulp.

Using this raw material, handmade paper with an absolute dry equivalent weight of 402 sheets was prepared using a TAPPI handmade sheet machine.

For comparison, the same pulp was used, heavy calcium carbonate 160% was used as filler, and rosin size 0.5 was used as sizing agent.
%, and 0.5% of Mannich-modified polyacrylamide as a cationic polymer substance were added. The zeta potential after addition was -5 mV. Handmade paper was prepared in the same manner as in Example 3 using this raw material.

The filler yield and paper quality test results for the obtained handmade paper are shown in Table 3.

Table 3 Comparing the results of Examples 1 to 3 and Comparative Examples 1 to 3 using the data shown in Tables 11-1 to 3, it can be seen that each of the Examples conducted using the method of the present invention was compared to the results obtained using the conventional method. Compared to each of the comparative examples, the filler yield was significantly higher in all cases, and claws containing a large amount of filler with an ash content of 40% or more were obtained, whereas in the conventional method, the same amount of filler was added. However, paper containing a large amount of filler with an ash content of 40 parts or more could not be obtained. In addition, the opacity of the paper has been significantly improved, and the strength (tear length) has been reduced to the same level or only slightly, resulting in a paper containing a large amount of filler with high opacity and little strength loss, which cannot be obtained with conventional methods. I was able to do that.

(Effects of the Invention) As described above, the present invention adds a filler and a cationic polymer substance to a pulp suspension, moves the zeta potential of the negative amount system to the positive side, and then adds the anionic polymer substance to the pulp suspension. by adding
By changing the zeta potential of the system from -5 to -10 mV during paper making, the yield of a large amount of filler added is improved, the paper quality is also highly opaque, and even if a large amount of filler is included, there is no decrease in strength. Paper with a low ash content of 40 or more could be obtained.

The paper obtained by the paper manufacturing method of the present invention can be effectively used as a processed base paper for information paper and the like.

Claims (1)

[Claims] Add filler and cationic polymer substance to pulp suspension,
Once the zeta potential of the system is moved to the positive side, an anionic polymer substance is added to increase the zeta potential of the system from -5 to -
Ash content 4 characterized in that paper is made by changing the voltage to 10 mV.
0% or more paper manufacturing method.