JP2964785B2 - Base paper for coated paper for printing - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a base paper for coated paper for printing. More specifically, the present invention relates to a base paper made of cellulose pulp coated on one or both sides with a coating liquid containing a pigment and an adhesive as a main component. Regarding the base paper used for the coated paper for printing formed by using the coating paper, in more detail, it is excellent in the operability of the paper machine for coated base paper, and the printing coated paper excellent in the ink deposition property for gravure printing. It relates to base paper for manufacturing.

[0002]

2. Description of the Related Art Base paper for printing coated paper (hereinafter simply referred to as coated base paper) is made from lignocellulose, especially cellulose pulp made from wood chips. The pulp that constitutes cellulose pulp is softwood bleached kraft pulp, hardwood bleached kraft pulp, or paper obtained by coating a coating base paper using a coater with a coating liquid mainly containing a pigment and an adhesive (hereinafter referred to as coated paper). Pulp), which is a recycled pulp made of coated waste paper consisting of cutting waste remaining after being cut to the size determined for each product, high yield pulp and waste paper used for improving printability, opacity and economy It is deinked waste paper pulp made from pulp.

[0003] In the pulp obtained by disintegrating coated waste paper, white pitch having a viscosity of about 0.01 to 5 mm derived from pigment and adhesive (mainly latex, a small amount of calcium carbonate, etc.) , Hereinafter simply referred to as “pitch”), and when a coated base paper is made using a pulp containing pulp obtained by disintegrating coated paper, felt, wire,
Pitch adheres to a press roll or the like, which causes problems such as a decrease in operability of a paper machine and a hole in a coated base paper. However, it is difficult to completely remove the pitch from the pulp mechanically because the pitch has little difference in specific gravity from the fiber component.

For this reason, techniques for detoxifying the pitch mixed in the raw pulp have been studied in the past, and a method of finely dispersing the pitch using a surfactant, adsorbing the pulp and removing the pitch out of the system, talc and cations A method in which the pitch is adsorbed using a system resin and removed as paper out of the system, and a method in which the tackiness of the pitch is eliminated using a water-soluble zirconium compound and the paper is removed out of the system (JP-A-55-122094, " ALPHA ", September 1991, pp. 83-85).

[0005] However, the method using a surfactant, talc, or a cationic resin is a method for stabilizing pitch particles ionically or stabilizing pitch by physical adsorption force. Thus, the pulp and white water are easily aggregated by the shearing force or the like when filtering (papermaking) from the pulp slurry, so it is hard to say that this is an effective method for solving the problem caused by pitch.

On the other hand, the method using a water-soluble zirconium compound utilizes the fact that the pitch loses tackiness by reacting the water-soluble zirconium compound with a functional group such as a carboxyl group or a hydroxyl group in the pitch component. Things. This method is effective for most sticky cohesive pitches generated in paper mills, and is a very effective method for solving the problem of sticking of pitch. The method using a compound is becoming the most common method for pitch control.

In the above-mentioned method using a water-soluble zirconium compound, the method of adding the water-soluble zirconium compound is not particularly limited as long as it can be mixed with the pulp in the step 15 to 30 minutes before papermaking and can be sufficiently stirred and mixed. Addition to previous processes, such as pulper for disintegrating coated broke, can cause cost problems without a significant increase in the water-soluble zirconium compound to achieve the desired effect. Therefore, it is common to add a water-soluble zirconium compound to pulp in a process 15 to 30 minutes before papermaking.

[0008]

In the method of adding a water-soluble zirconium compound, the pitch in the pulp obtained by disintegrating the coated paper does not lose its tackiness by reacting with the water-soluble zirconium compound. A part or all of the pitch is mixed with the pulp without adhering to the pulp, and is made into a base paper for coating to be removed outside the papermaking process system. As described above, when the pitch is formed in the coated base paper, the portion where the pitch is formed slightly protrudes from the surface of the coated base paper. In the past, machine calender processing was strengthened to eliminate this slight protrusion.However, not all small protrusions were crushed.The coating liquid was applied to the surface of such a coating base paper with a coater. When coated, fine blisters remain on the surface of the coated base paper. These minute bulges cause poor gravure printing ink deposition, which has reduced the product value of coated paper for printing.

[0009] The present invention is a coated base paper containing pulp from coated broke, which stabilizes the operation of a paper machine by eliminating the stickiness of pitch mixed in pulp from coated broke. It is an object of the present invention to provide a base paper for a coated printing paper, which is intended to have excellent gravure printing ink inking properties.

[0010]

In view of this situation, the present inventors have conducted intensive studies on the detoxification of pitch generated by disintegrating coated paper, and have found that the operability of a paper machine for making coated base paper. It is essential to use a water-soluble zirconium compound in the pulp from coated broke to ensure that the pitch having tackiness is difficult to be finely divided, but the pitch having lost tackiness It is easy to cut finely, the fineness of the pitch that has lost the adhesiveness improves the gravure printing ink coating of coated paper, and the method of finely dividing the pitch is most effective by beating treatment with a refiner. It was found to be expensive and completed the present invention.

The present invention relates to a base paper for coated paper for printing, wherein the pulp component constituting the base paper is 3 to 30% by weight (absolutely dry).
Added a water-soluble zirconium compound to the pulp slurry from which the coated paper was disintegrated,
The present invention relates to a base paper for coated paper for printing, wherein the base paper has a reduced content of 0 to 200 ml (CSF).

The coated broke used for making the coated base paper of the present invention includes cellulose pulp, talc, kaolin,
Inorganic pigments such as clay and calcium carbonate, and styrene
Butadiene copolymer latex (SBR), methyl methacrylate / butadiene copolymer latex (MB
It is a normal printing coated paper containing a latex such as R).

The defibration step of the coated damaged paper, which is performed in the papermaking process of the coated base paper of the present invention, is performed by a pulper or a defibrating machine used for ordinary waste paper processing. In the pulp slurry obtained from this defibration step, the latex used in the coated paper for printing forms a spherical white pitch having the above-mentioned viscosity of 0.01 to 5 mm together with a small amount of inorganic substances. Included.

The coated base paper of the present invention uses, as a part of the raw pulp, a pulp slurry obtained by adding a water-soluble zirconium compound to the pulp slurry to lose the stickiness of the pitch and then beaten. . Examples of the water-soluble zirconium compound to be added to the pulp slurry include ammonium zirconium carbonate, zirconium acetate, zirconium oxychloride, zirconium sulfate, zirconium nitrate, zirconium chloride, zirconium iodide, zirconium fluoride, zirconium oxysulfate, oxysulfate, Zirconium chloride, zirconium oxynitrate, zirconium oxybromide can be applied, but ammonium zirconium carbonate is most suitable for the present invention from the balance of price, ease of handling, effect of losing tackiness, time to effect manifestation, etc. I have. The addition ratio of the water-soluble zirconium compound is bone dry weight of the pulp zirconium oxide (ZrO ₂₎ is converted from 0.001 to 0.3 wt%.

If the rate of addition of the water-soluble zirconium compound is less than 0.001% by weight of zirconium oxide based on the weight of the dried pulp, the pitch loses its tackiness and the effect of the present invention cannot be obtained. If it exceeds 0.3% by weight, there is no difference in the effect and ammonium zirconium carbonate is wasted, so that the content is preferably 0.003 to 0.25% by weight.

The place where the ammonium zirconium carbonate is added is not particularly limited as long as a residence time (reaction time) of 15 minutes or more, preferably 20 minutes or more is provided until the paper is made after the addition. Since the desired effect cannot be obtained unless ammonium zirconium carbonate is sufficiently dispersed in the pulp slurry, it is necessary to sufficiently stir and mix the mixture by, for example, adding the zirconium carbonate to the suction of a pump for transferring the pulp slurry.

When the ammonium zirconium carbonate is added, the concentration of the pulp slurry is 0.3 to 15% by weight. If the concentration is less than 0.3% by weight, the desired effect can be obtained because the ammonium zirconium carbonate becomes too thin with the water of the pulp slurry. If it exceeds 15% by weight, it is difficult to mix it uniformly with the pulp slurry. Preferably it is 0.5 to 12% by weight.

Next, in order to remove the pitch from the coated waste paper in the pulp which has lost the tackiness, first, a treatment is performed using a screen for removing foreign matter in a known shape or a cleaner for removing foreign matter with a specific gravity difference. Is done. However, a pitch of 1 mm or less is difficult to remove with a screen, and the specific gravity of the pulp and the specific gravity of the pitch do not change so much that the pitch cannot be sufficiently removed even by a cleaner. If a pitch of this size is mixed into the raw pulp for papermaking, the coated paper manufactured from the coated base paper having the pitch formed thereon will have poor gravure printing ink depositability.

As described above, it is impossible to completely remove the pitch even if ammonium zirconium carbonate is added to the pulp from the coated broke to lose the adhesiveness.

Therefore, the present invention relates to a method for adjusting the pitch, which has lost the tackiness, to a pitch whose major axis is smaller than the fiber width of the pulp.
The particles are not shredded to a size of less than 5 mm and do not cause a decrease in the gravure printing ink adhesion of the coated paper. The cracking of the pitch is carried out by adding ammonium zirconium carbonate to the pulp from the coated waste paper, and after 15 minutes or more, preferably 20 minutes or more, beat the whole pulp.

Pulp from coated broke has a freeness of 350
It is about 500 ml (CSF). The pitch decreases as the freeness of the pulp decreases after the beating is increased. If the decrease in the freeness is less than 20 ml (CSF), the pitch is not sufficiently shredded. This is not preferable because the pulp fibers may be fined and the quality of the coated paper may be degraded, though the fibers are split. Beating reduces freeness by 20-200
It is preferred to adjust the pitch in the range of 30 ml (CSF), preferably 30-180 ml (CSF), to shred the pitch and render it harmless.

Since the tacky pitch is not shredded to a desired size even if it is treated with a refiner, it is essential for the present invention to add ammonium zirconium carbonate in a step before the refiner treatment so as to lose the tackiness. It is.

The pulp from the coated broke has a freeness of about 350 to 500 ml (CSF) after the screen treatment.
Since it is close to 500 ml (CSF), beating is not generally performed. However, in the case of the present invention, by performing the above-described beating, the freeness of the pulp from the coated waste paper is kept constant, and as a result, the freeness of the stock is stabilized and the formation of the coating original ground is reduced. Secondary effects such as improvement can also be achieved.

As described above, the pulp containing the pitch that has been beaten and detoxified is blended so as to occupy 3 to 30% by weight (absolutely dry) of the pulp component constituting the coated base paper. 3
When the amount is less than 30% by weight, the present invention does not need to be applied since the performance is as good as that of the beaten-treated pulp-free coated base paper, and when the amount exceeds 30% by weight, the filler contained in the pulp from the coated base paper ( Influences of the above-mentioned inorganic components) and the like become large, and the compounding ratio of the filler contained in the coated base paper material cannot be adjusted to a desired range, and the quality deteriorates such as a decrease in interlayer strength and a decrease in opacity of the coated base paper. Causes the
As mentioned above, it is important that the content is 3 to 30% by weight, preferably 5 to 25% by weight.

In making the coated base paper of the present invention,
In addition to pulping coated damaged paper as raw material pulp and detoxifying pitch, lignocellulose materials such as softwood and hardwood chips and non-wood cellulose from annual plants such as bagasse, kenaf, reeds, straws are crafted. Pulps obtained by bleaching pulp obtained by alkaline cooking such as pulping and pulp obtained by bleaching high yield pulp can be used. The usage ratio of various bleached pulp other than pulp from coated broke can be appropriately selected according to the quality required for the coated base paper.

Adding ammonium zirconium carbonate,
The effect of the present invention can also be obtained by a method in which pulp from coated waste paper that has been held (reacted) for 15 minutes or more, preferably 20 minutes or more, and the other pulp are mixed and beaten.

The papermaking method of the coated base paper of the present invention is not particularly limited, and a conventionally used papermaking method can be employed. For example, an acidic papermaking method performed at a papermaking pH of about 4.5 or a weakly acidic papermaking pH of about 6 to 9 containing an alkaline filler such as calcium carbonate as a main component.
A so-called neutral papermaking method, which is carried out with a weak alkali, may be employed. The coated base paper of the present invention can be formed into a paper having a rice area of about ²⁰ to 400 g / m ² , depending on the use and purpose.

When the coated base paper of the present invention is formed, a commonly used filler for internal addition can be used as needed. For example, talc, kaolin, clay, calcined kaolin, delamikaolin, heavy calcium carbonate, light calcium carbonate, magnesium carbonate, aluminum hydroxide, titanium dioxide, magnesium silicate, magnesium sulfate, calcium sulfate, satin white, white carbon, alumino One or two or more mineral fillers such as silicate, silica, bentonite and organic synthetic fillers (plastic pigments) such as polystyrene resin fine particles, urea formalin resin fine particles, and fine hollow particles can be appropriately selected and used. In addition, fillers contained in waste paper, broke (broken paper), kyogami, and the like can also be used effectively.

In addition to these, various internal additives such as anionic, cationic, nonionic or amphoteric retention improvers, drainage improvers, and paper strength enhancers which have been conventionally used are used. If necessary, it may be appropriately added to the pulp slurry. As an internal additive for papermaking, for example, a basic aluminum compound such as a sulfuric acid band, aluminum chloride, sodium aluminate and basic aluminum chloride and basic polyaluminum hydroxide, and a water-soluble aluminum such as an alumina sol easily dispersible in water. Compounds or various starches, polyacrylamide, polyethyleneimine, polyamine, polyamide / polyamine, polyethylene oxide, vegetable gum,
Examples thereof include urea formalin resin, melamine formalin resin, polyvinyl alcohol, latex, polyamide resin, dispersion of hydrophilic crosslinked polymer particles and the like, and derivatives or modified products thereof and compounds such as bentonite. Furthermore, a dye, a pH adjuster, a pitch control agent, a slime control agent, an antifoaming agent and the like can be appropriately added as needed.

The coated paper for printing is produced by coating one or both surfaces of the coated base paper of the present invention with a coating liquid containing a pigment and an adhesive as main components. This coating liquid composition is generally adjusted to have a solid concentration of 40 to 75% by weight, preferably about 45 to 70% by weight. In forming a coating layer by applying a coating liquid on a coating base paper, a coating layer in which the coating liquid has been applied once may be formed, or a multi-layer structure may be formed by dividing into an undercoat layer and an overcoat layer. It may be formed as. In the case of a multilayer structure, the coating compositions of the undercoat layer and the overcoat layer do not need to be the same, and the coating composition can be appropriately changed according to the required quality level.

As a method of forming a coating layer, a conventionally used coating apparatus such as a blade coater, an air knife coater, a roll coater, a reverse roll coater, a bar coater, a curtain coater, a die slot coater, a gravure coater, etc. The coating liquid is applied to the surface of the coating base paper using various coaters such as a chaplex coater, a brush coater, and a size press coater.
These coating apparatuses may be used in any form of on-machine or off-machine coater. The coating amount of the coating liquid on the coating base paper is usually 2 to 50 g / side on a dry weight basis.
Although it is about m ^2, it is desirable to adjust it in the range of about 5 to 30 g / m ² in consideration of blank paper quality, printability and the like of the obtained coated paper. The coated printing paper thus obtained is dried so that the water content is usually in the range of about 3 to 10% by weight, and then passed through an on or off super calender to perform pressure finishing. Done.

[0032]

EXAMPLES The present invention will be described more specifically with reference to examples and comparative examples below, but of course the present invention is not limited to these examples. Unless otherwise specified,% and parts in Examples and Comparative Examples are% by weight and parts by weight, respectively.

The pulp from the coated broke is a double coated paper having a coating amount of 10 g / m ² per one side,
The coated broke of m ² was pulverized by pulverizing with a pulper. The freeness of this pulp is 490 ml (CS
F), having a whiteness of 79.5% (Hunter whiteness) and containing a white pitch having a diameter of 0.01 to 5 mm, a pigment such as kaolin, and a filler such as calcium carbonate and talc. .

As zirconium ammonium carbonate, BACOTE 20 manufactured by Nippon Light Metal Co., Ltd. was used.

As other pulp, unbleached pulp is produced from softwood chips (15% Douglas fir and 85% domestic pine) and domestic hardwood chips using a kraft cooking liquor in a continuous digester manufactured by Kamiya Corporation. This was subjected to multi-stage bleaching (CEHD) to obtain a Hunter whiteness of 84.5.
% Bleached softwood bleached pulp (NBKP) having a freeness of 710 ml (CSF) and bleached hardwood pulp (LBKP) having a hunter brightness of 85.0% freeness (CSF) were used.

Example 1 0.04% by weight of ammonium zirconium carbonate (based on absolute dry pulp weight) at the suction port of a pump for adjusting the concentration of pulp from coated waste paper to 3.5% by weight and transferring it to a chest (As ZrO ₂ ). 20 in the chest
After a minute reaction, part of the pitch was removed with a 10-cut slit screen. After that, the pulp concentration was adjusted to 3.2% by weight, and the freeness was increased by 4 with a double desk refiner.
Adjusted to 65 ml (CSF) (freeness reduction amount 25 ml
(CSF)). Freeness from the coated broke is 460
490ml (CSF) pulp and freeness
460 ml of NBKP and freeness adjusted to (F) (CS
F) The LBKP adjusted to F) is mixed with 5% by weight: 25% by weight: 70% by weight based on the absolute dry weight of the pulp constituting the coated base paper, and the following fillers and chemicals are added or coated to form a long steel multi-cylinder dryer. Coating base paper was produced using a paper machine.

The base paper for coating was 41 g / m ^{2 of} rice tsubo and the water content was 5.5.
%Met. Filler (light calcium carbonate / talc = 80/20): 12% alkenyl succinic anhydride-based neutral sizing agent (manufactured by Oji National Co., Ltd., Fibran 68): 0.03% Sulfuric acid band: 0.5% cationized starch ( Oji National Co., Ltd., Kate F): 0.6% size press coated starch (Oji Constarch Co., Oji Ace A): 1.5 g / m ² size press coating alkyl ketene dimer (Kao Co., Cyclean) ): 0.02 g / m ²

In each of the following Examples and Comparative Examples, the above fillers and chemicals were added. The obtained base paper was coated on both sides with a coating liquid having the following composition using a blade coater, dried with an air foil dryer at 150 ° C., and further subjected to a super calender treatment to obtain 55.5 g /
A coated paper having m ² and a water content of 6% was produced. Kaolin (manufactured by EMC, HT clay): 70 parts Light calcium carbonate (average particle size: 1.2 μm): 30 parts Starch oxide (manufactured by Oji Constarch, Oji Ace A): 1.5 parts Styrene butadiene latex (Nihon Gosei) JSR-2294 manufactured by Rubber Co., Ltd.): 10.8 parts Including other dispersants, preservatives, and dyes The coating solution was used in each of the following Examples and Comparative Examples.

Example 2 0.2% by weight of ammonium zirconium carbonate (based on absolute dry pulp weight) at the suction port of a pump for adjusting the concentration of pulp from coated waste paper to 3.5% by weight and transferring it to a chest (As ZrO ₂ ). After reacting in the chest for 20 minutes, a part of the pitch was removed with a 10-cut slit screen. After that, the pulp concentration was adjusted to 3.2% by weight, and the freeness was adjusted to 31 by a double desk refiner.
Adjusted to 0 ml (CSF). (Freeness decrease 180
ml (CSF)) The freeness from the coated broke is 310.
520ml (CSF) pulp and freeness
F) Adjusted NBKP and Freeness (CSF) to 48
Coated paper was prepared in the same manner as in Example 1 except that LBKP adjusted to 0 ml was mixed with 28% by weight: 7% by weight: 65% by weight based on the absolute dry weight of the pulp constituting the coated base paper to produce a coated base paper. Was manufactured.

Example 3 The concentration of pulp from coated broke was adjusted to 3.5% by weight, and 0.2% by weight of ammonium zirconium carbonate was added at the suction port of a pump for transferring to a chest (based on the absolute dry pulp weight). (As ZrO ₂ per). 20 in the chest
After a minute reaction, a part of the pitch was removed with a 10-cut slit screen. 5% by weight: 25% by weight: 70% by weight based on the absolute dry weight of the pulp constituting the coated base paper with pulp from the coated broke from which a part of the pitch has been removed and NBKP and LBKP
After mixing, beat the mixture with a double desk refiner to obtain a freeness of 465 ml (CSF) (freeness reduction 25 ml (C
SF)). A coated paper was manufactured in the same manner as in Example 1 except that this pulp was used.

Example 4 A coated paper was produced in the same manner as in Example 1, except that zirconium acetate was used instead of ammonium zirconium carbonate.

Example 5 A coated paper was produced in the same manner as in Example 1 except that zirconium sulfate was used instead of ammonium zirconium carbonate.

Example 6 A coated paper was produced in the same manner as in Example 1, except that zirconium oxychloride was used instead of ammonium zirconium carbonate.

Comparative Example 1 In Example 1, the pulp from the coated broke was not treated with ammonium zirconium carbonate and beaten, but was simply treated with a screen to remove pitch, and used as raw pulp for coated base paper. Then, a coated paper was manufactured in the same manner as in Example 1.

Comparative Example 2 In Example 1, the pulp from the coated broke was treated with ammonium zirconium carbonate, then screened, and the freeness was 475 ml with a double desk refiner.
After adjusting to (CSF) (freeness reduction amount 15ml (CS
F)) A coated paper was produced in the same manner as in Example 1 by using it as base paper pulp of the coated base paper.

Comparative Example 3 In Example 2, the pulp from the coated broke was treated with ammonium zirconium carbonate, then screened, and the freeness was changed to 270 ml with a double desk refiner.
After adjusting to (CSF) (Freeness reduction amount 220ml (CS
F)), used as base paper pulp for coated base paper;
A coated paper was manufactured in the same manner as described above.

Comparative Example 4 In Example 2, the pulp from the coated broke was treated with ammonium zirconium carbonate, screened, and beaten to adjust the freeness to 310 ml (CSF). 520ml freeness
480ml of NBKP and freeness adjusted to (CSF)
Example 2 was prepared by mixing LBKP adjusted to (CSF) with 32% by weight: 7% by weight: 61% by weight based on the total dry weight of pulp.
A coated paper was manufactured in the same manner as described above.

With respect to the coated papers obtained in each of the above Examples and Comparative Examples, the operability of a paper machine for producing coated base paper, the gravure printing ink adhesion of coated paper, and the interlayer strength of coated base paper are as follows. And the quality was evaluated.

The operability of the paper machine The number of times the paper machine had to be stopped in order to remove the sticky substance attached to the paper machine was evaluated. ◎: The paper machine was not stopped at all for 7 days. 〇: The paper machine was stopped once in 7 days. Δ: The paper machine was stopped two or three times in 7 days. X: The paper machine was stopped 4 to 5 times in 7 days. XX: The paper machine was stopped six times or more in 7 days.

The degree of white spots on the printed matter printed by the ink inking property gravure printing adequacy test method (printing bureau system) was visually evaluated on a five-point scale. ◎: Excellent 〇: Excellent △: Normal ×: Slightly poor XX: Poor

Interlayer strength It measured by the following method based on TAPPI NO.19-77. Adhesive tape (Beiersdorf (Germany) tesa No. 4863, width 38 mm) is evenly pressed on both sides of the coated base paper, cut into a 15 mm wide scrambled shape, and then the adhesive tape on both sides of the scrambled tensilon is versatile. The interlaminar strength of the coated base paper was evaluated based on the tensile strength (g) required to peel off the paper layer of the coated base paper, using a mold tensile tester (manufactured by Toyo Bold-In Co., Ltd.). The higher the tensile strength (g), the higher the interlayer strength of the coated base paper. Table 1 shows the results.

The freeness of the pulp from which the coated waste paper was disintegrated was measured by diluting the pulp slurry (including the white pitch, pigment and filler) after disintegrating the coated waste paper with water to a predetermined concentration. Freeness (CSF) was measured.

[0053]

[Table 1]

Table 1 shows that Examples 1 to 6 are all excellent in the evaluation of each evaluation item. On the other hand, in Comparative Example 1 in which no water-soluble zirconium compound was used and no beating treatment was performed, the evaluations of the ink deposition property and the operability of the paper machine were extremely poor. In addition, even if a water-soluble zirconium compound was used, the beating treatment was not sufficiently performed, and thus the freeness reduction amount was 15%.
In the case of Comparative Example 2 having a small amount of ml (CSF), the evaluation of the operability and the interlaminar strength was good, but the evaluation of the ink inking property was low. As a result of excessive performance, the freeness reduction amount was 220 ml (CS
F) and the pulp from the coated broke used in Comparative Example 3, which is too much, satisfy the requirements of the present invention. It can be seen that any of Comparative Examples 4 which are out of the range of the mixing amount specified in the above results in a remarkable decrease in interlayer strength.

[0055]

As can be understood from the above description, according to the present invention, a pulp from a coated broke is treated with a water-soluble zirconium compound, and then beaten to lose the tackiness contained therein. After pulverizing the pulp from the beaten coated waste paper, a predetermined amount of pulp is used to form a coated base paper, whereby the decrease in operability due to adhesion of the sticky substance of the paper machine can be improved, and As a result of effectively reducing the fine protrusion of the gravure printing ink on the coated paper for printing manufactured using this coated base paper without lowering the interlayer strength. can do.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) D21H 17/66 D21C 5/02 D21D 1/20

Claims (1)

(57) [Claims] 1. A pulp component constituting a base paper having a content of 3 to 30.
(B) a water-soluble zirconium compound is added to the pulp slurry obtained by disintegrating the coated waste paper, and then the freeness is reduced by 20 to 200 ml (CSF) by beating to obtain a coating composition for printing. Base paper for industrial paper.