JP2706312B2 - Paper manufacturing method - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper manufacturing method, and in particular, has a remarkable effect of improving troubles caused by dirt in a preparation and paper making process, and furthermore, a paper such as a picking strength. The present invention relates to a method for producing paper which can be adapted to speeding up of a paper machine and high ash differentiation because the strength of the paper is improved and the drainage and the yield on a wire are extremely good.

"Conventional technology" Generally, in papermaking, in the pulp preparation process,
Fillers are added to pulp slurries to improve paper quality, such as whiteness, opacity, smoothness, writability, printability, and the like, and also to improve the feel and feel of paper.

In recent years, quality requirements for these papers have become strict, and on the other hand, high ash differentiation has been progressing to save pulp due to the deterioration of log conditions. Further, there is a demand for reduction in paper weight and correspondence to high-speed production, and there is an urgent need to establish technology for improving paper strength or yield.

Conventionally, in the acidic papermaking method of papermaking in the acidic range of pH 4 to 6,
Sulfuric acid bands have been widely used as fixing agents such as pulp fibers and fillers or as retention agents. On the other hand, in the neutral papermaking method in which the paper is made weakly acidic to weakly alkaline, an alkaline filler can be used, and as a typical example, it is now common to use calcium carbonate as a filler, and its demand is increasing year by year. In the direction.

By the way, in a papermaking method using, for example, calcium carbonate as an alkaline filler, a water-soluble polyvalent metal compound exhibiting acidic or weak acidity such as a sulfuric acid band is added to a pulp slurry containing calcium carbonate as an internal additive for papermaking. What is necessary is that carbon dioxide is generated by a chemical reaction with acid-calcium carbonate and foaming phenomenon occurs, or a hydroxide such as aluminum having stickiness is generated and becomes an adhered substance to prepare a raw material preparation system. This causes a so-called scale trouble that stains the inside of the paper machine system. Also, the addition of a sulfuric acid band or the like to a neutral papermaking system has a problem that the effect as a fixing agent or a paper strength enhancer as seen in acidic papermaking is significantly reduced, and polyvalent metals such as a sulfuric acid band. The use of the compounds in neutral papermaking systems was not aggressive. Therefore, in general, a large amount of expensive yield improvers, paper strength enhancers, and the like are used as substitutes for improving the yield or increasing the strength of the paper.

However, on the other hand, sulfuric acid bands are also inferior in the method of producing paper using an alkaline filler, due to circumstances such as being inexpensive and easy to handle, and being attractive and difficult to dispose of as a fixing agent and a paper strength enhancer as seen in acidic papermaking. It is also a fact that polyvalent metal compounds such as are used.

For example, a method of using a specific metal salt such as a sulfuric acid band after fixing a synthetic sizing agent (Japanese Patent Publication No. 6320/1988), a method of adjusting the zeta potential by adding an inorganic aluminum compound to a pulp slurry containing calcium carbonate (Japanese Patent Publication No. Sho 63-17958), a method of making paper containing a water-soluble aluminum salt together with a tertiary amine polyacrylamide paper strength agent (Japanese Patent Publication No. 62-24560), cationic aqueous dispersion of an organic ketene dimer A method of obtaining a neutral paper by adding a liquid, a water-soluble aluminum salt and a tertiary amine starch derivative (JP-A-59-199900) has been proposed. However, none of these methods is limited to a technique for improving the quality of paper, and is not sufficiently satisfactory as a technique for solving the problems, such as a foaming phenomenon and a stain, which should be originally considered as described above.

"Problems to be Solved by the Invention" In view of the current situation, the present inventors aimed at eliminating troubles caused by stains in the preparation and paper making process in a paper making method mainly using an alkaline amount, and picking. As a result of intensive studies on methods for improving the strength of paper such as strength, in particular, a water-soluble polyvalent metal compound excluding alkaline earth metals was previously added to the pulp slurry before adding the alkaline filler. By specifying the specific conductivity after the pulp slurry is well mixed, the polyvalent metal compound is sufficiently adsorbed on the pulp fiber, and as a result, the reaction with the alkaline filler is suppressed, and a very remarkable desired effect is obtained. It was found that it could be done.

[Means for Solving the Problems] The present invention relates to a method for making a paper by adding a filler mainly composed of an alkaline filler to a pulp slurry, wherein a water-soluble polyvalent resin in which an alkaline earth metal is previously removed from the pulp slurry. The metal compound is added within the range of 0.05 to 10 mmol per 100 g of the pulp fiber content, and the specific conductivity of the pulp slurry becomes
This is a method for producing paper, characterized in that an alkaline filler is added after adjustment to 15 mS / cm or less.

"Action" In general, pulp slurries for papermaking
P, NKP, waste paper, etc. are compounded, and various fillers, sizing agents,
Yield improvers, drainage improvers, paper strength enhancers, dyes, and other papermaking internal additives are added as needed, and a sheet is formed by a fourdrinier paper machine or a twin wire paper machine, etc. The paper is manufactured by being dried.

That is, the pulp slurry is prepared by mixing pulp fibers such as UKP, NKP and waste paper in a slurry state, alone or blended, and mixing with various preparation devices, that is, through a beating machine such as pulper, refiner, Jordan, etc. Pulp raw material chest, a pump for feeding liquid, and a selective process such as a screen and a cleaner.

Thus, according to the method of the present invention, a water-soluble polyvalent metal compound (hereinafter abbreviated as polyvalent metal compound) in which the alkaline earth metal has been previously removed is added to the pulp slurry before adding the alkaline filler.
Is added, and an alkaline filler is added after mixing and passing the pulp slurry by using at least one or more of the preparation devices described above. In order to maximize the effect of the compound, the specific conductivity of the pulp slurry after adding the polyvalent metal compound and the alkaline filler so that the concentration of the dissolved ionic substance does not increase (hereinafter abbreviated as SC) It has an extremely large feature in the specification of

Specifically, the polyvalent metal compound in the pulp slurry is 0.05 to 10 mmol, preferably 0.1 to 10 g, per 100 g of the pulp fiber.
It is added in the range of 1 to 8 mmol and specifies SC to 1.5 mS / cm or less, preferably 1.2 mS / cm or less,
Furthermore, it is necessary to specify SC after addition of the alkaline filler to 1.5 mS / cm or less, preferably 1.2 mS / cm or less. The SC is adjusted depending on the type of the polyvalent metal compound, the amount added, or the mixing conditions when adding to the pulp slurry, for the purpose of preparing the pulp slurry while the SC exceeds 1.5 mS / cm. When the process is carried out, a large amount of dissolved ionic substance reacts with or binds to the alkaline filler to cause contamination in the raw material preparation system and the paper machine system, and therefore, it must be avoided.

By preparing the pulp slurry by the method of the present invention in this way, the SC of the pulp slurry is maintained at 1.5 mS / cm or less in any system, and the zeta potential is adjusted to around 0. Is what it is.

The preparation device used in the mixing step is not particularly limited and can be used as appropriate. However, since the stirring of the device used is insufficient, the polyvalent metal compound and the alkaline filler to be added later come into direct contact. If a chemical reaction is caused to occur, it is difficult to obtain a desired effect. Therefore, it can be said that a device capable of providing a stirring force and a contact time such that the polyvalent metal compound is almost uniformly dispersed in the pulp slurry and sufficiently adsorbed to the pulp fiber is more preferable.

For example, a method of adding a polyvalent metal compound to a raw material chest containing a pulp slurry and stirring, and a method of further passing through a refiner or a liquid feed pump, or a method of providing a polyvalent metal compound addition port and providing a liquid feed pump A method of adding from the inlet side, a method of disintegrating pulp with water to which a polyvalent metal compound is added in advance, or a method of diluting and mixing a pulp slurry are included.

As the polyvalent metal compound used in the method of the present invention,
Although not particularly limited, for example, A1, Ti, Cr, Fe,
Co, Ni, Cu, Zn, Zr, Sn, Sb, Pb and other halides, oxyacid salts, organic acid salts, complex salts, etc. and colloids easily dispersible in water and basic compounds represented by the following general formula A polyvalent metal compound such as an aluminum compound is exemplified.

General formula [Al ₂ (OH) _n Cl _6-n ] _m General formula [Al ₂ (OH) _n (SO ₄ ) _{(6-n) / 2} ] _m (0 <n <6, 1 <m ≦ 20) Among these polyvalent metal compounds, Al, Fe, Sn, Zn chlorides, sulfates, organic acid salts and the like and colloidal liquids and the basic aluminum compounds represented by the above general formula particularly exhibit the desired effects of the present invention. Excellent in getting. In addition, from the viewpoint of toxicity, economy, whiteness, etc. of the metal compound, chlorides, sulfates, organic acid salts, alumina sol, sodium aluminate, and basic aluminum represented by the above general formula of Al Compounds are preferably used. If necessary, not only one kind but also two or more kinds of polyvalent metal compounds can be appropriately used in combination. In addition, it does not refuse to add various pH adjusters to adjust the pH of the slurry.

The filler is mainly composed of an alkaline filler, specifically, calcium carbonate, magnesium carbonate, or the like.Specifically, calcium carbonate has a large production amount and is economically inexpensive and industrially inexpensive. Useful for In addition, calcium carbonate, its type, manufacturing method, shape,
Regardless of the particle size and the like, for example, calcite-based light calcium carbonate, aragonite-based light calcium carbonate or dry-pulverized type, or wet-pulverized-type heavy calcium carbonate is appropriately selected depending on the use and quality of the paper, It can be used alone or in combination. Also, fillers generally known and used in the paper industry, such as talc, kaolin, clay, aluminum hydroxide,
Mineral fillers such as titanium dioxide, magnesium sulfate, silica, bentonite and the like, and organic synthetic fillers such as polystyrene resin fine particles, urea formalin resin fine particles, fine hollow particles and the like are appropriately selected and used in combination. Further, fillers contained in waste paper, broke, and the like can also be used effectively.

Of course, in addition to these, various anionic, nonionic, cationic or amphoteric retention improvers, drainage improvers, paper-strength enhancers, sizing agents, etc., are used in the pulp slurry. An internal additive for papermaking is appropriately selected and used. Specifically, various sizing agents such as petroleum resin sizing agent, alkyl ketene dimer sizing agent, alkenyl succinic anhydride sizing agent, rosin sizing agent, and styrene-acrylic sizing agent, polyacrylamide or its cationic And anionic and amphoteric modified products, polyethyleneimine and its derivatives, polyethylene oxide, polyamine, polyamide / polyamine and its derivatives, cationic starch, urea formalin resin, organic compounds such as polyamide resin and hydrophilic polymer particles, One or two or more of inorganic compounds such as colloidal silica and bentonite are appropriately used in combination, and further, an internal additive for papermaking such as a dye, a pH adjuster, a pitch control agent, a slime control agent, and an antifoaming agent. Can be appropriately added depending on the use of the paper. . It is also possible to apply starch, polyvinyl alcohol, latex, various surface sizing agents, pigments and the like to the surface of the paper using a device such as a size press, gate roll or bill blade.

On the other hand, as the pulp fiber, there is no particular limitation on the type and the like, but, for example, KP, SP, BCTMP, CTMP, CGP, in addition to chemical pulp and SCP such as softwood pulp and hardwood pulp obtained by AP, etc. Various types of mechanical pulp such as SGP, TMP, and RGP, non-wood pulp such as waste paper pulp such as DIP or hemp pulp, and synthetic pulp are used in appropriate combination.

The method of the present invention is applicable to all grades and types of paper products, for example, printing paper such as book paper, newsprint paper, gravure paper, art paper, coated paper, cast paper, lightly coated paper, and node paper. Writing paper and packaging paper,
It can be widely applied to information paper such as pressure-sensitive recording paper, heat-sensitive recording paper, electrostatic recording paper, and special paper such as tack paper.

As described above, the method of the present invention, particularly in a papermaking method using an alkaline filler as a main component, has been a problem in that it has conventionally been used for troubles caused by contamination in the preparation and papermaking process. This is an extremely preferable method for producing paper, since a metal compound can be positively used as an internal additive for papermaking, and further, a very remarkable effect can be obtained in terms of quality such as improvement in paper strength.

"Examples" Hereinafter, the present invention will be described more specifically with reference to examples, but is not limited thereto. The parts in the examples are parts by weight based on the pulp fiber content unless otherwise specified, and the amount of the polyvalent metal compound added is 100 g of pulp fiber.
Expressed in millimoles relative to

Example 1 A sulfate band was previously added to an LBKP chest containing LBKP.
Add 5 mmol and beat with a refiner to obtain 4 csf
50cc was set. To a pulp slurry composed of 75 parts of LBKP, 5 parts of NBKP of csf470cc, and 20 parts of coated paper broke, 20 parts of light calcium carbonate (trade name: TP-121, manufactured by Okutama Industry Co., Ltd.) and 10 parts of talc were added and mixed as fillers. And cationic starch (trade name: ONL-400, manufactured by Oji National)
0.5 parts and 0.1 part of an alkyl ketene dimer (trade name: Size Pine K-902, manufactured by Arakawa Chemical Industry Co., Ltd.) are added with good stirring, the pulp slurry is diluted with white water, and further anionic polyacrylamide (trade name: Percoll) 155,
Allied Colloid Co., Ltd.) was added to prepare an inlet raw material.

The obtained inlet material is paper-made with a fourdrinier
60 g / m ² of paper were obtained. Also, the pH and SC after LBKP passed through the refiner (measurement point A), the pH and SC after the filler was added (measurement point B), the yield of all raw materials (%), and the ash yield (%) , The picking strength of paper, and the state of stains due to scale-like deposits were measured and evaluated by the following methods, and the results are shown in Table 1.

[Specific conductivity (SC)]

100 samples of pulp slurry sampled at each measurement point
Filtration was performed using a mesh wire, and the filtrate was measured using a Laser Zee Model 500 (manufactured by PEM KEM), which is a method using a two-electrode cell.

[Yield of all raw materials]

 The concentration A (%) of the inlet raw material and the concentration B (%) of the white water were measured and calculated from the following equation.

[Yield of ash] Ash a (%) in the inlet material and ash b in the white water
(%) Was measured and calculated from the following equation.

[Picking Strength of Paper] Printing was performed using an RI printing adequacy tester (manufactured by Mei Seisakusho) and visually evaluated according to the following evaluation criteria.

A: Very good without picking.

：: good without picking

Δ: Picking slightly occurred.

X: Many picks occurred.

(Stain test)

The inlet material was filtered with a 100 mesh wire, and the filtrate 100 was circulated and poured onto a stainless steel plate at a flow rate of 100 ml / min for 10 days. The degree of staining after washing was visually evaluated according to the following evaluation criteria.

A: Excellent without any scale-like deposits.

：: Good dirt with no scale-like deposits.

Δ: Slightly stained with scale-like deposits.

×: Many stains due to scale-like deposits.

Example 2 In Example 1, the sulfate band 1 was previously added to the LBKP chest.
An inlet raw material was prepared and paper-made in the same manner as in Example 1 except that mmol was added. Table 1 shows the results of measurement or evaluation in the same manner as in Example 1.

Example 3 In Example 1, the sulfate band 3 was added to the LBKP chest in advance.
An inlet raw material was prepared and paper-made in the same manner as in Example 1 except that mmol was added. The results of measurement or evaluation in the same manner as in Example 1 are shown in Table-1.

Example 4 In Example 1, the sulfate band 5 was added to the LBKP chest in advance.
An inlet raw material was prepared and paper-made in the same manner as in Example 1 except that mmol was added. Table 1 shows the results of measurement or evaluation in the same manner as in Example 1.

Example 5 An inlet material was prepared and paper-made in the same manner as in Example 1 except that 2 mmol of ferrous sulfate was previously added to the LBKP chest instead of the sulfate band. Table 1 shows the results of measurement or evaluation in the same manner as in Example 1.
It was shown to.

Example 6 Example 1 was repeated except that, in place of the sulfuric acid band, 3 mmol of alumina sol (trade name: alumina sol-100, manufactured by Nissan Chemical Industries, Ltd.) was added to the LBKP chest in advance. Similarly, an inlet raw material was prepared and paper-made. Table 1 shows the results of measurement or evaluation in the same manner as in Example 1.

Example 7 An inlet raw material was prepared and paper-made in the same manner as in Example 1 except that 3 mmol of polyaluminum chloride was previously added to the LBKP chest instead of the sulfuric acid band. Table 1 shows the results of measurement or evaluation in the same manner as in Example 1.

Example 8 In Example 1, a basic polyaluminum hydroxide (trade name: Pah) was used instead of the sulfate band in an LBKP chest.
o # 2S, manufactured by Asada Chemical Industry Co., Ltd.) An inlet raw material was prepared and paper-made in the same manner as in Example 1 except that 3 mmol was added. Table 1 shows the results of measurement or evaluation in the same manner as in Example 1.

Example 9 In Example 8, the addition to the LBKP chest was stopped.
To the pulper for disintegrating LBKP, 8 mmol of the polyaluminum hydroxide used in Example 8 was added together with dilution water, and beaten with a refiner. An inlet raw material was prepared and paper-made in the same manner as in Example 8 except that the filler was replaced by 30 parts of heavy calcium carbonate (trade name: Softon 1200, manufactured by Bihoku Powder Chemical Industry Co., Ltd.). Table 1 shows the results of measurement or evaluation in the same manner as in Example 8.

Comparative Example 1 An inlet raw material was prepared and paper-made in the same manner as in Example 1 except that the sulfuric acid band was not added to the LBKP chest. Table 1 shows the results of measurement or evaluation in the same manner as in Example 1.

Comparative Example 2 The procedure of Example 1 was repeated, except that the sulfuric acid band was not added to the LBKP chest, but was beaten with a refiner, and 3 mmol of the sulfuric acid band was added to the same apparatus to which the filler was added. Inlet raw materials were prepared and paper-made. The pH and SC after LBKP passed through the refiner (measurement point A) and the pH and SC after addition of filler and sulfate band (measurement point B) were measured or evaluated in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 3 An inlet raw material was prepared and paper-made in the same manner as in Comparative Example 2 except that 5 mmol of the sulfuric acid band was added. Table 1 shows the results of measurement or evaluation in the same manner as in Comparative Example 2.

Comparative Example 4 An inlet raw material was prepared and paper-made in the same manner as in Comparative Example 2 except that ferrous sulfate was added in an amount of 2 mmol in place of the sulfate band. Table 1 shows the results of measurement or evaluation in the same manner as in Comparative Example 2.

Comparative Example 5 An inlet raw material was prepared and paper-made in the same manner as in Comparative Example 2 except that 3 mmol of the polyaluminum hydroxide used in Example 8 was added instead of the sulfuric acid band. Table 1 shows the results of measurement or evaluation in the same manner as in Comparative Example 2.

"Effects" As is clear from the examples in Table 1, the paper obtained by the present invention can significantly improve the stains in the preparation and paper making steps in its production, has a good raw material yield, and has a good picking strength. Improved paper was obtained.

Claims (4)

(57) [Claims] (1) A method for making a paper by adding a filler mainly composed of an alkaline filler to a pulp slurry, wherein a water-soluble polyvalent metal compound excluding an alkaline earth metal is previously added to the pulp slurry to a pulp fiber content of 100 g. The pulp slurry has a specific conductivity of 0.05 to 10 mmol.
A method for producing paper, comprising adding an alkaline filler after adjusting to 1.5 mS / cm or less. 2. The method for producing paper according to claim 1, wherein the specific conductivity of the pulp slurry after adding the alkaline filler is adjusted to 1.5 mS / cm or less. 3. The method according to claim 1, wherein the alkaline filler is calcium carbonate. 4. The method for producing paper according to claim 1, wherein the water-soluble polyvalent metal compound is an aluminum compound.