JPH02112499A - Paper making - Google Patents

Abstract

PURPOSE:To improve paper force regardless of acidic paper making system and neutral paper making system by adding an ionic polymer compound to a pulp slurry in the presence of a specific iron polysulfate and then making paper. CONSTITUTION:A pulp slurry is blended with an ionic polymer compound (preferably anionic acrylamide-based polymer or Mannich modified material of acrylamide-based polymer) in the presence of an iron polysulfate shown by the formula [when iron is ferric, k is 2 and l is 3; when iron is ferrous, k and lare 1; n changes with content of (OH); m is degree of polymerization] and made into paper.

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention relates to a paper manufacturing method that improves paper strength regardless of whether it is an acidic papermaking system or a neutral papermaking system, and exhibits an unprecedented paper strength enhancement effect. It is.

[Prior Art] Various paper strength enhancing agents are used in the paper manufacturing process, and these paper strength enhancing agents are broadly classified into natural polymeric substances and synthetic polymeric substances.

Starch and its derivatives are the most commonly used natural polymers.

On the other hand, commonly used synthetic polymers include polyethyleneimine, polyvinyl alcohol, polyamine polyamide shrimp chlorohydrin, and polyacrylamide. Among these, polyacrylamide is the most commonly used because there are many types of polyacrylamide because the degree of polymerization and cation/anion modification rate can be freely adjusted.

Such paper strength enhancers can be classified into ionic, nonionic, anionic, cationic, and amphoteric types that have a cationic group and an anionic group. However, since pulp fibers are negatively charged in water, nonionic and
Since anionic paper strength enhancers do not have self-fixing properties, sulfuric acid is usually used as a fixing aid (for acidic papermaking systems).

Of course, cationic and amphoteric paper strength enhancers having self-fixing ability are also used in acidic papermaking systems where sulfuric acid is used as a fixing aid.

On the other hand, in neutral papermaking systems in which sulfuric acid is not used as a fixing aid, cationic and amphoteric paper strength enhancers that do not require a fixing aid are predominant.

In recent years, neutral paper making has attracted attention from the viewpoint of the problem of oral deterioration of acidic paper in acidic papermaking systems, resource saving, energy saving, cost reduction, and ensuring novelty.

[Problem to be solved by the invention] A. Recent conversion rate of raw materials from softwood to hardwood.

Decrease in pulp quality due to increase in pulp and waste paper utilization ratio;
Furthermore, due to factors such as increased machine speed and closed papermaking systems, demands for paper strength enhancers are becoming increasingly sophisticated, and there is a desire to develop papermaking methods that are highly effective in increasing paper strength.

In response to these demands, single formulations of amphoteric paper strength agents or combination formulations of anionic paper strength agents and cationic paper strength agents have become popular, but these requirements have not been fully satisfied.

In particular, in neutral papermaking systems that do not use sulfate as a fixing aid, cationic polymers with fixing ability are used alone, or cationic polymers are used as fixing aids instead of sulfate, and other polymers are used as paper strength agents. However, in order to obtain sufficient paper-forming strength, these cationic polymers have to be used in extremely large amounts, which is a problem.

[Problem of invention]

An object of the present invention is to provide a paper manufacturing method in which an ionic polymer compound can exhibit a high paper strength reinforcing effect even when added in a relatively small amount in place of a conventional cationic polymer.

(Means for Solving the Problems) The present invention provides that, when adding an ionic polymer compound as a paper strength enhancer, when inorganic polymer flocculants, especially polyferric sulfate, are used in combination, the ionic polymer compound increases in strength. This was completed after discovering that it was possible to achieve a paper manufacturing method that improved the distillation rate and had a high paper strength enhancement effect.The paper was made by adding an ionic polymer compound to the pulp slurry in the presence of polyferrous sulfate. The main point is the paper manufacturing method.

The polyferric sulfate used in the present invention has the formula: CFek(OH)n(S04) ff
−n/2) m (for trivalent iron = 2. ffi
・In the case of 3.2-valent iron, =1. It is ff.l. n
changes depending on the content ratio of (011), the positive sign is the degree of polymerization,
Therefore, the values of 2, n, and - will change depending on the change in the ratio of divalent and trivalent iron, the content ratio of (0■), and the degree of polymerization.)
Typical divalent polyferric sulfate has a specific gravity of 1.45 or more, iron content of 11% or more, sulfate ion of 350 g/1 or more,
It has a viscosity of 10 cpS or more and a freezing property of -12°C+l'C, and is commercially available as a flocculant for water treatment.
There is no example of it being used in combination with an ionic polymer paper strength enhancer as a fixing aid in a paper manufacturing method, and it is characterized in that it improves its yield rate.

The ionic polymer compound used in the present invention is a water-soluble or water-dispersible polymer compound in which an anionic group alone, a cationic group alone, or both an anionic group and a cationic group coexist in the molecule. Copolymers prepared using the following monomers include monocarboxylic acids such as acrylic acid and methacrylic acid, maleic acid, and fumaric acid. , dicarboxylic acids such as itaconic acid, or alkali metal salts or ammonium salts thereof such as sodium salts and potassium salts.

On the other hand, typical monomers that provide cationic groups include dimethylaminoethyl (meth)acrylate,
Vinyl monomers having a tertiary amino group, such as diethylaminoethyl (meth)acrylate, dimethylaminopropyl (meth)acrylamide or diethylaminopropyl (meth)acrylamide, or their hydrochloric acid;
Quaternary ammonium obtained by reaction with a salt of an inorganic or organic acid such as sulfuric acid or acetic acid, or a quaternizing agent such as methyl chloride, hensyl chloride, dimethyl sulfate, or epichlorohydrin of the vinyl monomer containing a tertiary amino group. Examples include vinyl monomers containing salts.

In particular, the ionic polymer compound that most effectively acts for the purpose of the present invention is a derivative of acrylamide (or methacrylamide), and these can be added to acrylamide (or methacrylamide) by a known method and an anionic group alone. A cationic group alone or an anionic group,
It is a water-soluble or water-dispersible molecular compound that has both cationic groups introduced.

In particular, as the ionic polymer compound, it is preferable to use an anionic or amphoteric acrylamide-based polymer, and as the amphoteric acrylamide-based polymer, a Mannich-modified acrylamide-based polymer is used, or (A) acrylamide) Monomer 99°6~40
Using a copolymer of 0.2 to 30 mol % of (B) a water-soluble canon monomer/or its salt and (C) 0.2 to 30 mol % of a water-soluble anionic monomer/or its salt. is desirable in combination with polyferrous sulfate.

In carrying out the present invention, the amount or ratio of the ionic polymer compound and polyferric sulfate to be added can be set as desired in consideration of the strength of the target paper, but usually pulp slurry 100 0.05 to 5 parts by weight of an ionic polymer compound in the presence of 0.05 to 5 parts by weight of iron polysulfate
．． Add 05 to 10 parts by weight.

When carrying out the process during the paper manufacturing process, it is recommended to use a regular raw material [can be applied during the manufacturing process, but a mixing chest, mannchest, seed box, etc., where the raw material valve, ionic polymer compound, and polyallylamine resin are well mixed. It is desirable to add both at the same time or at separate locations before papermaking.

[Effect] Although the mechanism by which a high paper strength enhancing effect is obtained in a combined formulation of iron polysulfate and an ionic polymer compound is not clear, it is currently believed to be the result of the following functions.

In other words, - if there is no problem with formation of paper strength agents in the shell, the higher the retention rate (adsorption) for pulp fibers, the better the paper strength effect.Therefore, polyferric sulfate Because of its low molecular weight and high cationic charge, it promotes the aggregation of ionic polymer compounds when adsorbed at a higher density on the surface of pulp fibers than other cationic polymers. It is presumed that a strong bond with the polymer compound is realized, the yield rate of the ionic polymer compound is improved, and an excellent paper strength enhancing effect is obtained.

Hereinafter, the method of the present invention will be specifically explained based on Examples.

(Ionic polymer compound proboscis preparation example 1) In a 500 ml four-bottle flask equipped with a stirrer, a thermometer, and a reflux condenser, take the specified amounts of 40% acrylamide, 98% acrylic acid, and ion-exchanged water, and add 48% sodium hydroxide. The pH was adjusted to 6.0 and 15% monomer was dissolved in water. 1. At 80°C after the polymerization exotherm has stopped. The mixture was held for 5 hours to obtain an approximately 15% aqueous solution of anionic polyacrylamide.

Next, a part of the above anionic polyacrylamide aqueous solution was placed in another four-bottle flask, and a predetermined amount of 37% formalin and 50% dimethylamine aqueous solution were added thereto, and the mixture was heated at 50°C for 2 hours.
A time Mannich reaction was performed.

Table 1 shows the anionic polyacrylamide aqueous solution and the amphoteric polyacrylamide aqueous solution in the above preparation examples.

(Adjustment Example 2) Into a 500 ml four-bottle flask equipped with a stirrer, thermometer, and reflux condenser, take a specified amount of 40% acrylamide, dimethylaminoethyl methacrylate, 98% acrylic acid, and ion-exchanged water, and adjust the pH with hydrochloric acid. Adjust to 4.0 and set 15
% monomer aqueous solution, and then an ammonium persulfate aqueous solution and an acidic sodium sulfite aqueous solution were added as double polymerization initiators to initiate polymerization. 85°C after polymerization exotherm has stopped
of the amphoteric polyacrylamide for 1.5 hours.
%water? Eight liquids were obtained. Table 2 shows the amphoteric polyacrylamide aqueous solutions obtained in the above preparation examples.

(Preparation Example 3) 40% acrylamide 2-hydroxy-3 in a 500 ml four-bottle flask equipped with a stirrer, thermometer, and reflux condenser.
- Take predetermined amounts of methacryloxypropyltrimethylammonium chloride, 98% acrylic acid, and ion-exchanged water, adjust the pH to 4.0 with hydrochloric acid, and use 15% heptamine water (g as a polymerization initiator) Polymerization was started by adding an ammonium persulfate aqueous solution and an acidic sodium sulfite aqueous solution.After the polymerization exotherm stopped, the temperature was 1°5 at 85°C.
Hold for about 15% water + 8 hours of amphoteric polyacrylamide
I got the liquid. Table 2 shows the amphoteric polyacrylamide aqueous solutions obtained in the above preparation examples.

(Example 1-10 and Comparative Examples 1-12) Canadian Standard Freeness (abbreviated as C, S, F) 385ml corrugated pole waste paper beaten pulp 2.5%
Add ferric polysulfate [manufactured by Nippon Steel Mining Co., Ltd.] to the concentrated slurry.
Product name: Borinane] at 0.25% based on pulp solid content
A predetermined amount of the polymer obtained in Preparation Examples 1-1 to 1-10 was added.

After thoroughly stirring the above pulp slurry, paper was made using a TAPP standard square sheet machine (the pH at the time of paper making was
is 5.5). The obtained wet paper was dehydrated using an automatic press and then dried using a rotary drum dryer at 105 to 110'C for 3 minutes.

These will be referred to as Examples 1 to 10.

In Comparative Examples 1 and 2, ferric polysulfate was added to the pulp slurry at 0.25% and 0.5% based on the pulp solid content.
% was added, and the same operation as in the example was performed.

In Comparative Examples 2 to 12, the same mulberry cultivation as in Examples 1 to 1O was carried out, but papermaking was performed without adding polyferrous sulfate.

51,100 g/m obtained as above
The "specific bursting strength" of the paper was measured according to JIS P-8112.

The results are summarized in Table 3.

Examples 11-16 and Comparative Examples 13-18C, S, F3
A preparation example was prepared by adding 0.25% of polyferric sulfate (manufactured by Nittetsu Mining Co., Ltd., trade name: POLYTERRA) to 5 ml of corrugated cardboard defiberized valve 2.5% 4 degree slurry based on the pulp solid content. 2-1 to 23. A predetermined amount of the polymer obtained in 3-1 to 3-3 was added. After thoroughly stirring the above pulp slurry, paper was made using a TAPP standard square sheet machine (pH at the time of paper making was 5.5). The obtained wet paper was dehydrated using an automatic press, and then dried using a rotary drum dryer at 105 to 110''C for 3 minutes. Examples 11 to 16 were obtained.

In Comparative Examples 13 to 18, the same operations as in Examples 11 to 16 were performed, but papermaking was performed without adding polyferrous sulfate.

The specific bursting strength J of the paper of ffiloOg/rn obtained as described above was measured according to JIS P-8112.

The results are summarized in Table 3.

Table 1 (Wholesale Tsukuda 11) AM Niacrylamide To A; acrinois suggestion Polyferric sulfate addition amount: As Fe2O3/pulp solid content Table 2 (Silence [2° AM Niacrylamide AA Niacrylic Acid DM dimethylaminoethyl methacrylate = 2 hydroxy methacryloxypropyltrimethyl ammonium chloride Table 4 Amount of prepared polyacrylamide added = Weight%/solid content of bulk Amount of polycarbonate lamp:

Claims (5)

[Claims] (1) In the pulp slurry, the formula: [Fek(OH)n(SO_4)l-n/2]m(
For trivalent iron, k=2, l=3, for divalent iron, k
=1, l=1. A paper manufacturing method comprising adding an ionic polymer compound in the presence of polyferrous sulfate (n varies depending on the content of (OH) and m is the degree of polymerization) and then making paper. (2) The paper manufacturing method according to claim 1, wherein the ionic polymer compound is an anionic acrylamide polymer. (3) The paper manufacturing method according to claim 1, wherein the ionic polymer compound is an amphoteric acrylamide polymer. (4) The paper manufacturing method according to claim 3, wherein the amphoteric acrylamide polymer is a Mannich-modified acrylamide polymer. (5) The amphoteric acrylamide polymer contains (A) 99.6 to 40 mol% of an acrylamide monomer and (B) 0.2 to 3 of a water-soluble cationic monomer/or a salt thereof.
The paper manufacturing method according to claim 3, wherein the copolymer is a copolymer of 0 mol % and (C) a water-soluble anionic monomer/or a salt thereof.