JPS60119299A - 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 The present invention relates to a paper-making method, and more particularly to a paper-making method in which wire wear in a paper machine that occurs when heavy calcium carbonate is used as a paper-making filler is greatly improved.

J Shinban for Sho NIL is based on paper whiteness, opacity, smoothness,
Kaolin is added to valve slurry for the purpose of improving ink receptivity, writing suitability, coating suitability, etc., or for the purpose of making the paper feel good, and also as a filler. Inorganic substances such as , clay, talc, diatomaceous earth, titanium dioxide, and calcium carbonate have been used conventionally, and organic synthetic polymer substances have also been used in some cases. Among these fillers for papermaking, calcium carbonate in particular is in increasing demand as a filler as neutral papermaking develops in place of acidic papermaking, which has some problems.

Such calcium carbonate is divided into light calcium carbonate, which is chemically produced by blowing carbon dioxide gas into milk of lime, and heavy calcium carbonate, which is produced by mechanically crushing limestone and then classifying it by elutriation or water droplets. Broadly classified. Among these, light calcium carbonate is expensive and generally has a small particle size, resulting in poor yield and inability to impart sufficient paper strength to paper. On the other hand, heavy calcium carbonate
Limestone, the main raw material, is produced in large quantities in Japan and is produced locally, so it is not only available at a low price, but also has the advantage of being able to obtain products with a larger average particle size than light calcium carbonate. ing. However, since heavy calcium carbonate is manufactured by mechanical means such as crushing and classification, it has to have a wide particle size distribution and has sharp edges. If it is used as a filler, there is a risk that the wire of the paper machine will be significantly worn. Particularly, when plastic wires are used, the wear is severe.

As is well known, wire wear in a paper machine has a significant impact on papermaking efficiency, and severely worn wires must be replaced with new wires, but during this time the paper machine is stopped, resulting in a significant drop in productivity. Particularly in the case of twin-wire paper machines, which have made remarkable progress in recent years, the increased size and faster wire running have a significant impact on the productivity of wire replacement.

The disadvantage of heavy calcium carbonate is that it is extremely abrasive to paper machine wire, especially plastic wire.
The use of heavy calcium carbonate as a filler for papermaking is severely restricted, and in particular, it is one of the major factors preventing the industrialization of neutral papermaking technology that relies on the use of heavy calcium carbonate for purposes such as cost reduction. It is one.

As methods for improving the wire abrasion properties of heavy calcium carbonate as described above, methods such as (a) using a grade with a small average particle diameter, and (b) using a wet-pulverized product have been proposed. Satisfactory effects have not necessarily been obtained.

In view of the current situation, the present inventors have completed the present invention as a result of repeated research on methods for eliminating the wire abrasion properties of heavy calcium carbonate, not only on processing methods for heavy calcium carbonate but also on the entire papermaking system. I ended up doing it.

The present invention is a papermaking method using heavy calcium carbonate as a papermaking filler, which is characterized in that the heavy calcium carbonate is mixed with a cation-modified starch aqueous solution in advance and then added to the paper stock.

More specifically, the present invention involves adsorbing cation-modified starch on the surface of particles of ground calcium carbonate by mixing ground calcium carbonate and an aqueous cation-modified starch solution, and then adding this to the paper stock as a filler for papermaking. It is added to.

According to the results of the tests conducted by the present inventors, starches other than cationically modified starch, such as raw starch or oxidized modified starch, can be adsorbed onto the surface of heavy calcium carbonate, but the amount of adsorption is small. It was revealed that even if the mixing ratio of .

As the cationically modified starch used in the present invention, for example, 2-diethylaminoethyl chloride is added to starch.

Alternatively, there may be mentioned various starches in which a tertiary amino group or a quaternary ammonium group is introduced into the molecule by reacting with a cationizing agent such as 2,3-epoxypropyltrimethylammonium chloride. Cation modification (m) is particularly modified with a tertiary amino group and/or a quaternary ammonium group, with a nitrogen content of 0.05 to 0.35%,
More preferably in the range of 0°08 to 0.2%,
In particular, the viscosity of a 2% aqueous solution of 4 J at 25°C is 20 cp.
Starch with a rating of s or more is particularly preferably used because it is adsorbed in large quantities by heavy calcium carbonate and has an extremely excellent effect of improving wire abrasion properties.

As mentioned above, the important feature of the present invention is that the ground calcium carbonate is mixed with the cationically modified starch aqueous solution in advance and then added to the paper stock. Since the adsorption reaction progresses relatively easily if both are mixed under stirring, the mixing method is not particularly limited. For example, a cation-modified starch aqueous solution is added to a heavy calcium carbonate dispersion, or a cation-modified starch aqueous solution is added to a cation-modified starch aqueous solution.
(powder), kneading powdered heavy calcium carbonate and cationically modified starch aqueous solution, and further heating a dispersion containing both cationically modified starch) powder and heavy calcium carbonate while stirring. Various methods are possible, such as adsorbing the 119 powder onto the surface of heavy calcium carbonate while gelatinizing it.

In addition, the mixing ratio of ground calcium carbonate and cation-modified starch is appropriately selected depending on the type, pulverization method, and average particle size of the ground calcium carbonate used, as well as the type and nitrogen content of the cation-modified starch. However, there is a tendency for the degree of improvement in wire abrasion resistance to correlate with the absolute amount of cation-modified M 153 adsorbed on ground calcium carbonate. It is preferable to adsorb starch.

In addition, in the present invention, in addition to the cation-modified starch, an anionic polymer such as sodium polyacrylate may be used as 4M within a range that does not impede the effects of the present invention. In addition, after adsorbing cation-modified stagnation on heavy calcium carbonate, the resulting heavy calcium carbonate is dried once and used by re-dispersing it in water before adding it to paper stock. It is also possible to add additional techniques such as treating heavy calcium carbonate dispersed in an aqueous starch solution with a crusher such as a Sun I mill, and simultaneously performing crushing, mixing, and adsorption.

The specific heavy calcium carbonate thus obtained is added to paper stock along with various known fillers for paper making, if necessary, and paper is made.

According to the papermaking method of the present invention, the wire abrasion resistance of heavy calcium carbonate used as a filler for papermaking is significantly improved compared to conventional dry-pulverized products as well as wet-pulverized products. This reduces the frequency of wire replacement in conventional paper machines by a factor of 1, making it possible to make paper with extremely high productivity.

The present invention will be described in more detail with reference to Examples below, but it is of course not limited thereto.

Note that % in the examples indicates weight % unless otherwise specified.

Examples 1 to 3 Heavy calcium carbonate (Loughton 1200. Bihoku 15) manufactured by Kasha, which is a dry-pulverized classified product with an average particle size of 4.4μ.
A 5% dispersion was prepared.

This dispersion was divided into three equal parts, each containing cationically modified starch modified with quaternary ammonium groups (Amylofax OO,
(manufactured by Abebe), 0.5% (Example ■) and 1.0% (Example 2) in terms of solid content based on heavy calcium carbonate.
), and 2.0% (Example 3), and then the solid content concentration of heavy calcium carbonate was 2%.
Dilute each dispersion liquid to give three types of dispersion liquids for evaluation of Wight abrasion properties.

The abrasion resistance is determined by fi'I' li[l
i L, ta.

+1] A weight of 1 kg was placed on a plastic paper making wire (O3-60, manufactured by Nippon Filcon Co., Ltd.) cut into a length of 50 mm and a length of 250 mm. While rotating the ceramic roll at a circumferential speed of 400 m/min, add 1q of the above wire abrasion resistance + 1& liquid so that the contact angle is I05°.
Circulate the wire LM IJ (with a flow rate of min.), weigh the wire weight decrease M after 1 hour, and take this value as the wire wear amount (IIlg). did.

The results are shown in Table 1.

The average particles of the ground calcium carbonate used, the nitrogen content of the cation-modified starch, the viscosity of the starch paste solution, and the dust absorption IN adsorbed on the ground calcium carbonate were each measured by the following methods. The results are also listed in Table 1.

■ A portion of the heavy calcium carbonate dispersion with an average particle size of 25% was taken, and a phosphoric acid-based dispersant was added thereto in an amount of 0.1% based on the weight of the heavy calcium carbonate, and the dispersion was sufficiently dispersed. Thereafter, the average particle diameter (μ) was measured using an X-ray transmission-natural sedimentation type particle size distribution analyzer (Sedigraph 500 (model 1-01, manufactured by Konsei Seisakusho).

■ Nitrogen content of cationically modified starch The nitrogen content (%) was measured by the Microkjöldahl method.

(2) Viscosity of cation-modified starch paste The starch paste was diluted to a concentration of 2%, and the viscosity (cps) at 60 revolutions per spindle was measured at 25°C using a Brookfield type viscosity needle 11.

■ A portion of the dispersion liquid was collected from the dispersion liquid for starch adsorption and wire abrasion evaluation.
Centrifuge this for 1 () minutes in a centrifuge (2500G) for 8 minutes.
It was 11. 5 g / 251 np of the obtained supernatant
R iodine solution 2.5 rrt Il and 1:3 hydrochloric acid solution 11
] m Add R and then add water to make a total of 59 m
The absorbance at 580 nm was measured using a spectrophotometer (UV I DEC-505 model).

(manufactured by JASCO Corporation).

From the obtained absorbance, calculate the amount of starch remaining after melting using a calibration curve prepared in advance with each paste ('/191tJ), subtract this from the amount of starch initially added and mixed, and add the remaining amount to heavy carbonate. This was regarded as the amount of R powder adsorbed on calcium, and was expressed as adsorbed liters (mg) per 1 g of heavy calcium carbonate.

Example 4.5 Instead of the ground calcium carbonate used in Examples 1 to 3, ground calcium carbonate (Nisscalon #8°O1 manufactured by Sankyo Seifun Co., Ltd.), which is a dry-pulverized classified product with an average particle size of 3.4 μm, was used.
and further cationically modified starch (Cato-3) modified with a tertiary amino group.
15, manufactured by Tamago National Starch Co., Ltd.), and the addition and mixing ratio of cod starch paste to heavy calcium carbonate was 0.5% (Example 4) and 1.0% (Example 5) in terms of solid content. Two types of dispersions for wire abrasion evaluation were prepared in the same manner as in Examples 1 to 3 except for the above.

Using the obtained dispersion liquid, the amount of wire wear was measured by the method described above, and the results are listed in Table 1.

In addition, the average particle diameter of heavy calcium carbonate, the nitrogen content of cation-modified starch, the viscosity of starch paste liquid, and the amount of starch adsorption were also measured by the above-mentioned method. The results are also listed in Table 1.

Example 6.7 In place of the cationically modified starch used in Examples 1 to 3, cationically modified starch modified with quaternary ammonium groups (
Bozamil E-7. (manufactured by Abebe), and the addition and mixing ratio of starch paste liquid was 0.5% (Example 6) and 1% (in terms of solid content).
．． Two types of dispersion liquids for wire abrasion evaluation were prepared in the same manner as Examples 1 to 3 except that the dispersion liquid was 0% (Example 7).

Using the obtained dispersion liquid, the amount of wire wear was measured by the method described above, and the results are shown in Table 1.

Further, the nitrogen content, starch paste viscosity, and R powder adsorption m of the cation-modified starch are also listed in Table 1.

Example 8 In addition to the cation-modified stagnation liquid in Example 7, anionic polymer polyacrylate monolithium (Aronhe-9, manufactured by Toagosei Co., Ltd.) was added to heavy calcium carbonate. A dispersion liquid for wire abrasion evaluation was obtained in the same manner as in Example 7 except that 0.05% in terms of solid content was added and mixed.
The amount of wire wear was measured and the results are listed in Table 1.

Example 9.10 Heavy calcium carbonate (-grade, manufactured by Sankyo Seifun Co., Ltd.), which is a dry-crushed product with an average particle size of 14.7μ, was prepared at a solid concentration of 50.
% dispersion, and this dispersion has an average grain diameter of 4.6μ.
After sand milling so that
% heavy calcium carbonate dispersion. Using this dispersion, the addition and mixing ratio of the cationic modified starch paste was 0.5% (Example 9) and 1.0% (Example 10) in terms of solid content.
) except that a dispersion liquid for wire abrasion evaluation was prepared in the same manner as in Examples 1 to 3, and the amount of wire abrasion was measured. The results are shown in Table 1.

Comparative Example 1 A dispersion liquid for wire abrasion evaluation was prepared in exactly the same manner as in Example 1 except that the cation-modified starch paste liquid was not added and mixed, and the amount of wire abrasion was measured. The results are shown in Table 2.

Comparative Example 2 The same procedure as in Example 4 was conducted except that the cation-modified starch paste liquid was not used, and the amount of wire wear was measured. The results are shown in Table 2.

Comparative Example 3 A heavy calcium carbonate dispersion (HydroCarbo 30. manufactured by Briuse-Stauffer, solid content concentration 72%), which is a wet-pulverized product with an average particle size of 1.8 μm, was mixed without adding anything, and the solid content concentration was reduced. The dispersion liquid was diluted to 2% to obtain a dispersion liquid for wire abrasion evaluation.

The amount of wire wear was measured using this dispersion, and the results are listed in Table 2.

Comparative Example 4.5 In Example 1, raw +
1W17) (cornstarch, manufactured by Tamago Cornstarch Co., Ltd.) was added and mixed at 1.0% (Comparative Example 4) and 3.0% (Comparative Example 5) in terms of solid content to heavy calcium carbonate. Type 4 Abrasion Evaluation Phase TL&Liquid was obtained. The amount of wire wear was measured using these dispersions, and the results are shown in Table 2.

Comparative Example 6 In Example 4, oxidation-modified υIt) (Ace A, manufactured by Tamago Cornstarch Co., Ltd.) was used instead of the cation-modified m powder paste liquid.
The wight abrasion loss was measured in the same manner as in Example 4, except that 2.0% solid content was added to the size liquid, and the results are shown in Table 2.

Patent applicant Kanzaki Paper Co., Ltd.

Claims (1)

[Claims] fll A papermaking method using heavy calcium carbonate as a rent for papermaking, characterized in that the heavy calcium carbonate is mixed with an aqueous solution of Yme cation-modified starch and then added to the paper stock. Paper making method. (2) Cation modified stagnant) is modified with tertiary amino group and/or quaternary ammonium group,
．． Claim No. 1, which is starch with a nitrogen content of 35% (
Paper making method described in section 1).