JPH03234894A - Production of coated paper for printing - Google Patents

Abstract

PURPOSE:To obtain the subject coated paper for printing having excellent printability by applying a coating composition containing a pigment and an adhesive to a base paper containing a specific regenerated waste paper pulp as a pulp component and subjecting the surface to calendering. CONSTITUTION:The base paper used in the present process has a kinetic wettability of from -0.32 to +0.15 and a surface smoothness of >=12% measured by specular reflection smoothness tester under 20kg/cm<2> pressure and contains >=3wt.% of a pulp regenerated by deinking process including a mechanical agitation procedure under the application of compressive force to waste paper in the presence of a surfactant-based deinking agent. The objective coated paper can be produced by coating the base paper with a coating composition composed mainly of a pigment and an adhesive, drying the coating layer and calendering the surface.

Description

Detailed Description of the Invention "Industrial Application Field" The present invention relates to a method for manufacturing coated paper for printing, and in particular, the present invention relates to a method for producing coated paper for printing, and in particular, the present invention relates to a method for producing coated paper for printing. This invention relates to coated paper for printing with excellent printability, which is obtained using base paper blended with recycled pulp.

``Traditional Techniques'' In recent years, with the progress of office automation, it is predicted that a ``paperless'' society will be brought about, but office buildings and factories still produce large amounts of information paper called OA paper. is being discharged. On the other hand, the consumption of coated paper for printing is rapidly increasing due to the increase in visual, color, and luxury of newly developed insert advertisements, magazines, and advertisements. Garbage disposal is currently a serious social problem.

Japan's waste paper recovery rate is approximately 50%, which is higher than other developed countries. Looking at the breakdown, 90% of paper is recovered for new paper, and approximately 40% is used for newsprint production.
of waste paper pulp is reused.

However, when attempting to reuse waste paper such as OA paper or coated paper for printing as recycled pulp, various problems arise in terms of quality, so the actual situation is that it is hardly reused.

Therefore, the reality is that OA paper and coated paper for printing are collected and incinerated after use. For this reason, we are not only concerned with increasing incineration costs in each local government and the limited capacity of landfills, but also with the protection of global resources (preventing the decline of forest resources), and the problem of global warming caused by carbon dioxide generated from waste paper incineration. As part of the solution to international environmental problems such as
There is an urgent need to recycle these used papers.

A recovery method for obtaining recycled pulp has been proposed as a way to reuse recycled pulp from these waste papers. Among these proposals, the so-called high-concentration kneading system method (hereinafter referred to as "high-concentration kneading system method") uses a hydrophilic surfactant-based deinking agent while applying mechanical agitation while applying compression with a kneader or disperser. (referred to as the HDK method) is attracting attention. However, in this method, the pulp fibers in the waste paper treated are strongly treated with a special surfactant under heat and pressure, so the recycled pulp obtained has physical properties that are quite different from ordinary pulp fibers. show. For example, coated paper for printing using Kawahara paper, which is a coated paper blended with recycled pulp obtained by the HDK method, has problems such as reduced printing smoothness.

[Problems to be Solved by the Invention] The present invention aims to solve the problem of the coated paper surface, which is generated when recycled pulp obtained from waste OA paper or printing paper is reused for printing coated paper by the HDK method. The purpose is to improve smoothness.

``Means to solve the problem'' Conventional newsprint and corrugated paper, which are coated on base paper with pigments and adhesives as their main ingredients, have already reached their limits, so until now they have not been covered. There is a strong desire for the application of recycled paper pulp to office automation paper, printing paper, etc.

However, it is quite difficult to obtain pulp similar to normal bleached pulp from used OA paper, printed paper, etc.

In other words, most office computers, personal computers, word processors, printer paper for fax machines, and office paper such as copy paper are printed with toner containing resin components, and even printing paper does not have offset printing. As it is printed with printing ink containing a large amount of resin components (especially in the case of rotary offset printing),
It is extremely difficult to peel and remove colored ink (printing and printing pigments) from paper. In addition, when these papers are coated papers, chemicals in the coating layer often develop color during the waste paper processing process, and the coating layer often interferes with repulping.

On the other hand, in a method for producing coated paper for printing, in which various types of OA paper and waste paper for printing are coated with an acid, dried, and then finished with a calender, the paper is produced as a pulp component in the base paper under the following conditions. The base paper contains 3% by weight or more of recycled pulp, and the dynamic wetting value of the base paper is -0.32 to +0.1.
5 g, and the surface smoothness of the base paper as measured by a specular reflection smoothness meter under a pressure of 20 Kg/cm2 is 12% or more.

[Conditions for producing recycled pulp from used paper]

``Recycled pulp of waste paper obtained by a deinking process that includes a mechanical stirring process that applies compressive force to waste paper in the presence of a surfactant-based deinking agent'' We conducted intensive research on a method for introducing recycled pulp obtained by waste paper processing into coated paper base paper for printing.As a result, we found that the cause of the decrease in printing smoothness that is observed when using recycled pulp from used paper is different from that of conventional paper. Even virgin pulp or waste paper valves, waste paper valves that do not comply with the HD K method, and even common loss paper generated at paper mills,
When compared with conventional base paper obtained by blending simple recovered pulp obtained from unprinted waste paper, the coatability of the base paper is poorer, especially its wettability and smoothness for coating liquids. It was determined that this was the main cause of the decrease in printing smoothness of the resulting coated printing paper.

By the way, as a method for obtaining recycled pulp from used paper, it is carried out by appropriately combining - boat fishing with a disintegration process, a rough selection process, a selection process, a deinking process, and a bleaching process.

In the disintegration step, a low-density pulper, a high-density pulper, etc. are used, and in the rough selection and selection steps, a flotation method, a main selection method, and a compromise method are appropriately selected depending on the type and/or quality of the recycled pulp.

Here, the waste paper processing method using the HD K method is based on the conventional processing methods, such as the combination of sodium sulfite and caustic soda, the earth kettle high-pressure cooking and cleaning method, the solvent method, the pulper immersion cleaning method, the pulper immersion flotation method, etc., and the use of chemicals and heat. Unlike the conventional deinking method, which melts or emulsifies and disperses printing ink, resin, etc., it has lower wetting suitability and faster wetting between prints), and is finished as a coated paper for printing. It was also found that the smoothness during subsequent printing pressurization was also reduced.

In addition, Paper and Pulp Technology Times, August 1986 issue, page 29, describes the case of using the HDK method and the case of deinking pulp (DIP) obtained by the conventional pulper immersion floatation method without using the HDK method. A comparison of the quality of the paper produced is shown. This experimental example relates to double embossed toilet roll paper, which is different from the coated paper base paper of the present invention, but the Klemm water absorbency (mm per minute) measured value, which is common to paper in general, was higher than that of the comparative paper at 22 mm. The size is 25 to 28 mm, indicating that the property has changed to absorb water more easily in this case as well. In this way, the phenomenon of increased water absorption of paper is a desirable property for toilet roll paper and other uses and is not a problem. It causes a decrease in the smoothness of the coated paper obtained by coating objects, and is critical for the quality of coated paper for printing.The high concentration paper stock (waste paper) of about 15% or more is agitated with a strong force such as a Ni-Goo. The mechanical stirring action of the machine applies strong and uniform friction and compressive force to the waste paper fibers, and at the same time, the printing ink is removed by the action of the surfactant-based deinking agent that has already been added. A method of converting foreign matter such as printing ink into uniform ultrafine particles and removing the foreign matter such as printing ink that has become uniform ultrafine particles using the flotation method (Paper Paper Technology Association Journal, June 1988 issue 1-
Page 17, Paper and Pulp Technology Times; August 1988 issue 25
~31 pages, Japanese Patent Publication No. 61-11353, etc.), and the present inventors believe that this HDK method can be applied to general waste paper and especially waste paper such as OA paper and printing paper, which are difficult to recycle and have recently become a social problem as mentioned above. We believe that this is an excellent method for obtaining recycled pulp from.

That is, although the physical properties of base paper for coated paper using recycled pulp obtained by the HDK method are not yet well understood, according to the experimental results of the present inventors, it is possible to A base paper containing this is not preferable because it will cause defects in the water-based paint applied as a post-process.

The reason why the water absorption and wettability of recycled pulp obtained by the HDK method increases is that during the deinking process, the surfactant-based deinking agent is subjected to strong agitation compression force such as kneading along with the waste paper. Because the surfactant not only adsorbs to the surface of the waste paper pulp but also penetrates into the inside of the pulp fibers, the surfactant is not completely removed even after thorough washing and dehydration in the post-process. This is thought to be because the hydrophilic surfactant cannot be removed and remains in the recycled pulp.

Therefore, when the concentration of waste paper pulp treated while applying compressive force such as kneading becomes so large as to exceed 20% by weight, a significant decrease in coating suitability is observed.

The present inventors have developed base paper for coated paper manufactured using recycled pulp obtained by the HDK method in order to improve the coatability without affecting the smoothness of base paper for coated paper. Klemm water absorption, Cobb water absorption,
When the correlation with the printing smoothness of coated paper was investigated by varying the Steckigt sizing degree, etc., no satisfactory correlation could be found. Therefore, as a result of further intensive research, we discovered that there is a good correlation between the dynamic wettability value of base paper.
We have finally completed the present invention.

Here, the dynamic wettability value of the base paper represents the change in the magnitude of the adhesion force to water over time as a measure of wettability.
/Resca ■). That is, 2
A test piece of
It measures the degree of wetting over time (adhesion force) when immersed in a depth of mm for 10 seconds, and the smaller the value of the degree of wetting (hereinafter referred to as dynamic wetting value), the harder it is to get wet. The larger the value, the easier it is to get wet. As a result of further research on this wetting value, it was found that, as a temporal wetting value measured with this tester, the wetting value 2 seconds after immersion in water has a very large effect on the smoothness of the coated paper. In other words, it has become clear that when the value is large (the wettability of the base paper is high), a coating device such as a blade is applied onto the base paper, resulting in a decrease in quality such as a weakening of the surface strength. In the case of base paper made from recycled pulp, special care must be taken as the fibers themselves have poor wet beatability and tend to become short fibers, reducing the surface strength of the base paper itself.

Therefore, in the present invention, the dynamic wetting value of the base paper is set to 0.32.
〜+0.15 g, more preferably −0.30〜+OL
It is specified in the range of og. By the way, 1015g
If it exceeds 0.32g, the coating property with the coating liquid will decrease and the smoothness of the coated paper will be inferior.On the other hand, if it is less than -0.32g, the adhesive force between the base paper and the coating layer will decrease, which is preferable. do not have.

On the other hand, the dynamic wetting value of base paper can be controlled by controlling the pulp composition, beating conditions, type and amount of filler, paper strength agent, internal sizing agent, pH1 surface sizing agent, surface treatment agent, paper density, wire mesh, This can be carried out by manipulating various conditions such as hydrofoil arrangement, paper filler distribution, smoother pressure, press pressure, and drying temperature. These measures also apply to papermaking speed 3. During the heating drying process after coating, measuring and smoothing, the coating liquid loses fluidity and solidifies for a short period of time (usually several seconds). Furthermore, since the coating liquid flows into the fiber gaps of the base paper, the smoothness of the surface of the coating layer smoothed by a blade or the like decreases. Conventional methods to prevent the coating liquid from flowing into the fiber gaps of the base paper during the coating process include adding cationic acrylamide, aluminum metal salt, etc. to the coating liquid as an auxiliary agent to promote solidification of the coating liquid. Although methods have been proposed, there are almost no examples of this being put into practical use because the fluidity and stability of the coating liquid are significantly reduced.

However, the relationship between the dynamic wettability of the base paper and the dynamic wettability of the base paper is unknown.
When using recycled paper pulp obtained by the DK method, the pulp fibers are treated with a surfactant and a strong mechanical stirring action, so there is a particular correlation with the smoothness of the resulting coated paper. It is well recognized. Also,
When the value is small, the compatibility between the coating layer (liquid) and the base paper often affects the reduction in low 2 degree, and it is determined by appropriately selecting the optimal paper-making conditions specific to each paper machine.

On the other hand, when lowering the dynamic wetting value of the base paper, not only does the surface strength of the coated paper decrease as described above, but also the air permeability, curling suitability, etc. tend to decrease, and furthermore, the papermaking speed decreases and the sizing agent This tends to result in increased costs, such as increasing the amount of internal filler.

Therefore, as a workaround, the optimum value is determined as appropriate in accordance with the quality target of each product, also taking into consideration the specular reflection type smoothness of the base paper, which will be described below.

Generally, as the amount of recycled pulp obtained by the HDK method is increased, it is preferable to set the dynamic wettability value of the resulting base paper to be successively lower.

Furthermore, in the method of the present invention, as described above, 3% by weight or more of recycled pulp obtained by the HDK method is blended into the pulp composition of the base paper for coated paper, and the dynamic wetting value of the base paper is determined. In addition, a specular reflection type smoothness meter (measurement pressure;
If the treatment is performed so that the measured value at 20 kg/cm2) is 12% or more, more preferably 14% or more, an extremely excellent smoothness improvement effect can be obtained. Incidentally, when the content is 14% or more, even better smoothness of the coated paper can be obtained compared to the case of the prior art which does not contain recycled waste paper pulp.

The recycled pulp obtained by the HDK method is beaten twice to make paper, and is then subjected to powerful mechanical treatments such as disintegration using a waste paper pulper and high-concentration two-densing treatment to make the pulp into short fibers. As a result, recycled pulp has the advantage of good smoothness of the resulting paper, but on the other hand, recycled pulp has a history of being made into paper and dried to a moisture content of approximately 3 to 7%, so recycled pulp cannot be used in normal paper making. It has the disadvantage that it is stiffer than the wet pulp used in wet pulp, is less susceptible to smoothing treatment, and the base paper is bulkier, reducing the micro-smoothness of the finished base paper.

The present inventors focused on this point, and in the method of the present invention, if the measured value of base paper containing recycled pulp with a specular reflection type smoothness meter (measurement pressure: 20 Kg/cm2) is 12% or more, the base paper It was discovered that the effect of improving the smoothness of coated paper can be obtained using this method. Of course, if the base paper is coated with an undercoat using an on-machine size press or coater, the measurement is performed in the state of the coated base paper.

The specular reflection type smoothness meter referred to here is a device that measures the smoothness of paper by pressing it against the glass surface under constant pressure conditions. The printing smoothness of coated paper for printing obtained by the method of the present invention is not affected by the air permeability of the paper, as is the case with the Heck smoothness meter and Barker Printsurf, which are air leakage type smoothness measuring instruments. This shows an extremely high correlation with improvement.

The most preferred method for smoothing the surface of the base paper of the present invention is a smoothing treatment in a wet bar during the papermaking process, such as pulp composition, beating conditions, wire mesh, felt mesh, press pressure, smoothing roll treatment, etc. Furthermore,
Machine calender It is also good to add soft calender, gross calender, super calender treatment, etc. on machine or off machine. In the invention, the measurement value of the base paper with a specular reflection type smoothness meter is 1
Merely specifying 2% or more cannot significantly improve the smoothness of coated paper, and it is only when combined with the specification of the dynamic wetting value of the base paper that the synergistic effect achieves the desired excellent smoothness. This results in the effect of improving smoothness.

In other words, although the smoothness improvement principles of the two (the dynamic wettability value of the base paper and the smoothness measured by a specular reflection type smoothness meter) are different from each other as mentioned above, it is rather assumed that the effects act synergistically. Conceivable. The upper limit of the value measured by a specular reflection type smoothness meter (measurement pressure: 20 kg/cm") on base paper is not particularly stipulated, but if this value is increased, a blade coater may be used in the coating process. If this is done, streaks, scratches, etc. tend to occur easily, and the thickness of the coated paper tends to decrease, so it is preferable to keep it at 30% or less.

Therefore, the higher the regular reflection type smoothness value of the base paper, the better, but it is better to appropriately determine the optimum value in consideration of the dynamic wetting value and the desired quality characteristics of the corresponding product.

The regular reflection type smoothness of the base paper is 6 layer is more effective.

As mentioned above, the coated paper base paper for printing of the present invention contains 3% by weight or more of waste paper recycled pulp obtained by the HDK method in its pulp composition. % or less, there is almost no change in the water absorption, wettability, rigidity, etc. of the resulting base paper, so no particular improvement effect on the base paper is observed, and the recycled pulp content is 3% by weight or more. In this case, the desired improvement effect of the present invention becomes noticeable.

The recycled pulp obtained by the HD K method in the present invention refers to the method described in the above-mentioned Paper Bag Technology Association Journal, Paper Pulp Technology Times, Japanese Patent Publication No. 11353/1983, etc. A method for deinking waste paper, which includes the step of mechanically treating the pulp in the presence of one or more surfactant-based deinking agents while applying compressive force with a refiner, kneader, two-wheel mixer, disperser, etc. at a pulp concentration of obtained by.

As the surfactant, those having an HLB value of 11 to 14 are often used in order to obtain a high white color. Waste paper 8 In terms of information-related paper, uncoated printer paper for computer computers, word processors, fax machines, etc., coated printer paper such as thermal paper and pressure-sensitive copying paper, and copy paper such as Xerox paper, etc. O
A Waste paper, cast paper, art paper, coated paper, lightly coated paper,
Coated paper such as matte paper or high-quality paper, colored high-quality paper, notebooks, stationery, wrapping paper, fancy paper, medium-quality paper, newsprint,
Saragi and Super Kake are paper, imitation paper, pure white roll paper, uncoated paper such as milk cartons, used paperboard, acidic paper,
Neutral paper, chemical pulp paper, high yield pulp (SGP, BS
C: Paper containing P, BCTMP, TMP, RGPCNP, etc.), waste paper standard quality specification table; Used paper as listed in the Waste Paper Recycling Promotion Center Summary, including printing, copying, printing, and non-printing. Regardless, it is not particularly limited.

Furthermore, the coated paper for printing obtained by the present invention includes ordinary coated paper for printing, in which a coating composition mainly composed of pigments and adhesives is coated on a base paper, and after drying, a calender finish is applied. It is manufactured through the same manufacturing process.

In the method of the present invention, some coated printing paper base papers necessarily contain high-yield pulp due to the quality specifications of the coated printing paper used as the product.

In this case, the content of high-yield pulp is arbitrary and is not particularly stipulated. For example, if high-yield pulp is included in recycled pulp, this point should be taken into consideration in product quality specifications, etc. The required amount of high-yield pulp is determined accordingly.

However, according to the study results of the present inventors, based on the method of the present invention (in the base paper of coated paper for printing, when high-yield pulp is contained in the base paper, the content rate of high-yield pulp is It has become clear that the desired effects of the present invention are particularly pronounced when the content is adjusted to 20% by weight or less, more preferably 10% by weight or less, in the pulp composition constituting the base paper.

The reason why the method of the present invention is particularly effective when applied to base paper containing a large amount of bleached chemical pulp is not necessarily clear, but first, the smoothness of the coated paper obtained is This refers to processed base paper that involves printing, such as tank paper and metallized paper, which are said to have a high degree of hardness, and includes all coated papers that are printed using various printing methods such as offset, gravure, letterpress, and flexography. . For example, super art paper, art paper, coated paper, lightly coated paper, label paper, bulky coated paper, packaging paper, fancy paper, coated paper for metallization, and matte coated paper such as dull and cloaked paper. The paper is coated on one or both sides, and the base paper contains bleached or unbleached chemical pulp, high-yield pulp (SGP, BSCP, PGP, TMP, CTMPB).
CTMP, RGP, CGP, CMP, SCP, etc.) are coated papers such as base paper and paperboard.

Calender finishing methods include super calender, gross calender, soft calender, and soft compact calender (Paper Valve Technology Times/1932)
August 2, pp. 31-36; PP1 / November 1987
Monthly issue, pp. 45-47, WFP/1985, 2
2.873-877) can be applied on-machine or off-machine. Note that the calender roll temperature in this case should be adjusted appropriately within the range of about 20 to 350°C, and that the physical properties such as dynamic wettability and rigidity of the recycled pulp obtained by the HD K method are better than those of chemical pulp. Because it is closer to high-yield pulp than high-yield pulp, the smoothness improvement effect is more clearly seen in base paper with a higher content of chemical pulp that is replaced with chemical pulp than when replaced with high-yield pulp. It is assumed that.

The coating composition used in the method of the present invention contains pigments and adhesives as main components, similar to conventional coating liquids for coated paper. Examples of pigments include clay, kaolin, aluminum hydroxide, lucium carbonate, titanium dioxide,
One or more of the usual pigments for coated paper, such as barium sulfate, zinc oxide, satin white, calcium oxide, talc, plastic pigments, etc., may be appropriately selected and used.

Examples of adhesives include proteins such as casein, soy protein, and synthetic proteins; conjugated diene copolymer latex such as styrene-butadiene copolymer and methyl methacrylate-butadiene copolymer; acrylic ester and/or methacrylic acid. Acrylic polymer latex such as a polymer or copolymer of ester 2, vinyl polymer latex such as ethylene/vinyl acetate polymer, or various polymer latexes thereof with a monomer containing a functional group such as a carboxyl group. Modified alkali-soluble, alkali-swellable, or alkali-insoluble polymer latex and various synthetic resin polymers called binder pigments; synthetic resin adhesives such as polyvinyl alcohol, olefin/maleic anhydride resin, and melamine resin; Oxidized starch, positive starch, esterified starch, de:)-strine, etc. are used in one category; one or more of the usual adhesives for coated paper, such as carboxin methyl cellulose derivatives, etc., are selected and used as appropriate. .

Generally, the amount of adhesive is 4 to 5 parts by weight per 100 parts by weight of pigment.
It is blended in an amount of about 0 parts by weight, more preferably about 10 to 30 parts by weight. Furthermore, antifoaming agents,
Various auxiliary agents such as colorants, mold release agents, flow modifiers, etc. are blended as appropriate.As auxiliary agents that promote solidification of the coated layer, for example, amine, amide, poly-3, paperboard machines using a combination of the three, Yankee, etc. There are dryer machines, etc., and either acidic papermaking or alkaline papermaking may be used.Of course, medium base paper containing high-yield pulp can also be used. Additionally, base paper pre-coated with a size press, bill blade, etc. can also be used.

The amount of coating liquid applied to the base paper is generally about 3 to 50 g/rrf per side in terms of dry weight, but it is 5 to 30 g when considering the blank quality of the resulting coated paper, printability, etc.
It is desirable to adjust within a range of about / m.

In addition, various methods for drying the wet coating layer include conventionally known methods such as steam heating, air heating, gas heater heating, high frequency heating, electric heater heating, infrared heater heating, laser heating, and electron beam heating. A drying method can be adopted as appropriate.

"Example" The present invention will be described in more detail with reference to Examples below, but of course the scope is not limited thereto. In addition, unless otherwise specified, "part" and "%" in the examples respectively refer to "part" and "%".
5 parts by weight and 5% by weight, 100 parts by weight of acrylamide, salts of polyvalent metals such as zinc, aluminum, magnesium, calcium, barium, etc.
It may be added in an amount of 0.1 to 10 parts by weight.

The coating liquid can be used in general coated paper manufacturing processes, such as blade coaters, air knife coaters, roll coaters, etc.
Reverse roll coater, bar coater, bill blade coater, curtain caulk, die slot coater,
The base paper is coated in one layer or in multiple layers using an on-machine or off-machine coater equipped with a double-sided or single-sided coating device such as a gravure coater, a Champlex coater, or a size press coater.

The solid content concentration at that time is generally about 40 to 75% by weight, but in consideration of repeatability, a range of 45 to 70% by weight is preferable. As the base paper, paper-based or board-based base paper with a weight of about 30 to 400 g/rd, which is used for general coated paper, is used, but the paper making method is not particularly limited, and generally known and publicly used top wire etc. Including fourdrinier machine, round net machine, 4 shown.

Examples 1 to 3 A mixture of OA waste paper, high-quality coated paper, and uncoated printed paper was disintegrated using a pulper together with an alkaline aqueous solution, and screened to remove foreign substances such as plastics and adhesives. The pulp was dehydrated until the pulp concentration was 30%. In the pulp thus obtained, NaO was added in an amount relative to the pulp.
H3%, NazSi034%, H20□3%, and 0.4% of a surfactant-based deinking agent (trade name: DI 600/manufactured by Kao Corporation) were added, mixed with a mixer, and then mixed with a heated knee gun. After compression stirring treatment, heat at approximately 60°C for 2 hours.
Holds time. Next, dilute this pulp liquid to about 1%,
After flotation treatment and deinking, foreign matter was removed with a cleaner and dewatered with a filter to obtain recycled pulp with a whiteness of 78%.

The recycled pulp obtained in this way was beaten in a double disc refiner, with 40% NBKP and 30% NBKP.
A pulp blend slurry consisting of 20% LBKP and 10% loss paper contains heavy calcium carbonate as a filler, alkyl ketene dimer 6 as a sizing agent (trade name: Barcon/manufactured by Disoku Hercules), and polyamide epichlorohydrin (manufactured by Disoku Hercules) as a fixing agent. Product name: Kaimen/manufactured by Disoku Hercules), cationic starch (
(manufactured by Tamago National Co., Ltd.) was added, treated with a mixture of oxidized starch and styrene/maleic anhydride surface sizing agent in a size press, and the dynamic wetting value was -0.28 g on a fourdrinier paper machine with a papermaking speed of 500 m/min. (Example 1) , -0.05g
(Example 2), +0.10 g (Example 3), and 20 Kg each 7 cm2 Paper was made so that the specular smoothness value under pressure was 15%, and 70 g/m2 base paper for coated paper was prepared. I got it.

Next, kaolin (product name: UW-90/manufactured by EMC) 8
A pigment consisting of 0 parts and 20 parts of fine particle heavy calcium carbonate (trade name: Cargotal 90/manufactured by Fuji Kaolin Co., Ltd.) was mixed with sodium polyacrylate-0.2 as a dispersant for the pigment.
Dispersed with a Coles dispersion machine using
% pigment slurry was adjusted. The pigment slurry thus obtained was mixed with 5 parts of oxidized starch (solid content) and styrene-bookdiene copolymer latex (trade name, JS RO69).
6/manufactured by Japan Synthetic Rubber Co., Ltd. - 13 parts of solid content) was added, and water was further added to obtain a coating liquid with a solid content concentration of 60%.

The coating liquid thus obtained was applied to both sides of the base paper at a dry coating rate of 80 g/m2 per side.
Coated with a blade coater at a speed of about 12 m/min.
It was dried in a dryer at 0°C to obtain a coated paper with a moisture content of 6%.

This coated paper was subjected to super calendering at a surface temperature of 60° C. and a linear pressure of 200 kg/cm. The quality of the coated paper for printing thus obtained was measured, and the results are shown in Table 1.

Example 4 A coated paper for printing was obtained in the same manner as in Example 1, except that the paper was made so that the value measured by a specular reflection type smoothness meter was 12%. The quality measurement results of the obtained coated paper for printing are shown in Table 1.

Comparative Example 1 As the base paper of the comparative example, NB was used without using recycled paper pulp.
The valve composition consists of 40% KP, 50% LBKP, and 10% common loss paper, with the addition of heavy calcium carbonate as a filler to make the paper ash content 12%, and alkyl ketene dimer (size UL) 0 per bulb.
．． 05%, and polyamide epichlorohydrin 0.02
Coated paper for printing was obtained in the same manner as in Example 1, except that the paper was treated with a 2% oxidized starch solution in a size press and paper was made using a Fourdrinier paper machine at a papermaking speed of 800 m/min. . The quality measurement results of the obtained base paper and coated paper for printing are shown in Table 1.

Comparative Example 2 In the process of obtaining regenerated pulp, a mixer was used instead of a kneader and the agitation treatment was carried out at a valve concentration of 10%.
A coated paper for printing was obtained in the same manner as in Comparative Example 1, except that the bulb composition was made of 30% BKP, 20% LBKP, and 10% co-horizontal paper. The quality measurement results of the obtained base paper and coated paper are shown in Table 1.

In this case, the whiteness of the recycled bulbs obtained was as low as 72%, and therefore the whiteness of the coated paper obtained was low (and the paper surface also appeared cloudy, and colored foreign matter appeared in spots). Because it was widely recognized as a coated paper for printing, it lost its commercial value as a coated paper for printing.

Comparative Example 3 As base paper, 40% recycled pulp obtained in the same manner as in Example 1, 30% NBKP, 20% LBKP, 10% loss paper
A coated paper for printing was obtained in the same manner as in Comparative Example 1 except that a valve formulation of % was used. The quality measurement results of the obtained base paper and coated paper for printing are shown in Table 1. In this case, although the wettability was significantly reduced, no colored foreign matter in the arrangement as in Comparative Example 2 was observed.

Comparative Example 4 Coated paper for printing was obtained in the same manner as in Example 1, except that the base paper was made so that the dynamic wetting value was -0.35 g and the value measured by a specular reflection type smoothness meter was 15%. Ta. Table 1 shows the quality measurement results of the obtained coated paper for printing.

Comparative Example 5 A coated paper for printing was obtained in the same manner as in Example except that the base paper was made to have a dynamic wettability value of +0.17 g and a specular reflection smoothness value of 11%. The quality measurement results of the obtained coated paper for printing are shown in Table 1.

90 Example 5 In the processing step for obtaining the recycled pulp of Example 1 as base paper, a refiner was used instead of a kneader, the pulp treatment concentration was 20%, the surfactant was replaced with a score roll, and Triton N -101 (Rohm&Has
(manufactured by S Company) 0.3% and oleic acid soap 0.3% were used. The whiteness of the recycled pulp at this time was 76%. Recycled pulp thus obtained: 8%, NBKP: 40%
, 32% LBKP, and 20% 5GP, and the paper was made so that the dynamic wettability value of the base paper was -0.10g, the specular smoothness value was 28%, and the base paper weight was 48g/m. As a result, coated paper Kawahara paper was obtained.

Next, kaolin (product name: UW-90/manufactured by EMC)
In a pigment consisting of 60 parts and 40 parts of fine particle heavy calcium carbonate (trade name: Carbicle 90/manufactured by Fuji Kaolin Co., Ltd.),
Sodium polyacrylate as a dispersant for pigments 0
．． 2 parts were added and dispersed using a Coles disperser to prepare a pigment slurry with a solid content concentration of 68%. The oxidized starch (solid content) in this pigment slurry was 11% on a Type 31 smoothness meter. Next, a medium quality coated paper for printing was obtained in the same manner as in Example 5. The quality measurement results of the obtained coated paper are shown in Table 2.

Comparative Example 7 Regenerated pulp was obtained in the same manner as in Example 5, except that in the process of obtaining regenerated pulp, the pulp concentration in the refiner was set to 10% and stirring was performed. The recycled pulp thus obtained was 8%, NBKP40%, LBKP32%, 5GP2.
A base paper for coated paper was obtained in the same manner as in Comparative Example 6 except that the pulp composition was 0%. The dynamic wetting value of this base paper is +0
．． It had a specular reflection type smoothness of 11%. This base paper was coated in the same manner as in Example 5 to obtain coated paper for medium quality printing. The quality measurement results of the obtained coated paper are shown in Table 2.

In this case, the whiteness of the recycled pulp obtained is as low as 70%, and therefore the whiteness of the coated paper obtained is low, the paper surface also appears cloudy, and colored foreign matter appears in spots. Because it was widely recognized, it lost its commercial value as a coated paper for printing.

Comparative Example 8 3 parts, styrene-butadiene copolymer latex (trade name, JS RO696/manufactured by Japan Synthetic Rubber Co., Ltd. - solid content)
18 parts were added, and water was further added to obtain a coating liquid with a solid content concentration of 60%.

This coating liquid was coated on both sides of the base paper using a blade coater at a speed of 800 m/min so that the dry coating amount was 6 g/m2 per side, and dried with a dryer at 130°C to reduce the moisture content to 6%. A coated paper was obtained.

The thus obtained coated paper was subjected to a super calender treatment under the conditions of a surface temperature of 90° C. and a linear pressure of 280 Kg/am to obtain a medium-quality coated paper for printing. The quality measurement results of the obtained coated paper are shown in Table 2.

Comparative Example 6 NBKP40 without using recycled pulp as base paper
%, LBKP 40%, GP 20%, and paper was made by adding 0.05% modified rosin size, 3% sulfuric acid, and talc to 10% paper ash per bulb. A base paper for coated paper was obtained in the same manner as in Comparative Example 1. The dynamic wetting value of the base paper at this time was +0.17 g, specular reflection 2. As the base paper, recycled pulp obtained in the same manner as in Example 5 was 8%, NBKP 40%, LBKP 32%, 5GP 20%.
A coated paper for printing was obtained in the same manner as in Comparative Example 6 except that a pulp composition consisting of the following was used. The quality measurement results of the obtained base paper and coated paper for printing are shown in Table 2. In this case, although the wettability was lowered, no colored foreign matter like that in Comparative Example 7 was observed.

Example 6 A mixture of newly developed waste paper and printed waste paper was disintegrated using a pulper in an alkaline aqueous solution, and screened to remove foreign substances such as plastics and adhesives, resulting in a pulp density of 2.
It was dehydrated to 7%. In addition, N per pulp
aOH2%, NazSiOs 4%, 11□0□3%,
Surfactant-based deinking agent (trade name: DI600R/manufactured by Kao Corporation) 0.4%, and (trade name, DI300/manufactured by Kao Corporation)
0.3% was added, compressed and stirred with a heated niegu, left for about 70 minutes, diluted to about 1%, deinked by flotation, and dehydrated to achieve a whiteness of 72%.
4 recycled pulp with a freeness of 350 cc was obtained. The recycled pulp thus obtained was 10% by weight, 40% by weight of NBKP, and 30% by weight of LBKP.
A paper stock is prepared by adding 0.5 parts of rosin size, 4 parts of sulfuric acid hand, and 5 parts of talc as a filler to the pulp in a pulp composition consisting of 20% by weight of 5GP, and this paper stock is made into paper. Dynamic wetting value -0.15g, specular smoothness 14% using on-machine soft calender
A matte coated paper base paper having a base paper basis weight of 45 g/m2 was obtained.

Next, 20 parts of kaolin (trade name i HT/manufactured by EMC) and 80 parts of heavy calcium carbonate having an average particle diameter of 1.2 μm were placed in a Coles dispersion machine using 0.2 parts of polyacrylic acid soda as a dispersant. A pigment slurry having a solid content concentration of 70% was prepared. Add to this slurry 5 parts of acrylic alkali-sensitive synthetic resin emulsion as an adhesive and 1 part of carboxymethyl cellulose as a thickener.
The pH was adjusted to 9.5 with caustic soda, and water was further added to obtain a coating liquid with a solid content concentration of 60%.

A paper stock was prepared by applying this coating liquid to both sides of the above-mentioned base paper for matte coated paper, and paper was made from this stock to obtain base paper for coated paper. The dynamic wetting value of this base paper was +0.17 g, and the specular smoothness was 11%. This base paper was coated in the same manner as in Example 6 to obtain a matte coated paper for gravure printing. The quality measurement results of the obtained coated paper are shown in Table 3. In this case, the whiteness of the recycled pulp obtained was as low as 71%, the white paper appearance of the obtained coated paper was cloudy, and many colored foreign substances were observed as spots, so it was considered to have no product value. became.

Comparative Example 10 A matte coated paper for gravure printing was obtained in the same manner as in Comparative Example 9, except that recycled pulp obtained in the same manner as in Example 6 was used as the base paper. The quality measurement results of the obtained base paper and matte coated paper for gravure printing are shown in Table 3. Although the dynamic wetting value of the base paper in this case was lower, colored foreign matter in the arrangement as in Comparative Example 9 was not observed.

In addition, each measurement method in Table-1, Table-2, and Table-3 is as follows.

7 was coated with a blade coater at a speed of 80 parts m/min so that the dry coating amount was 13 g/m2 on one side.
After drying in a dryer at °C, a coated paper with a moisture content of 6% was obtained.

The thus obtained coated paper was subjected to a super calender treatment under conditions of a surface temperature of about 100° C. and a linear pressure of 250 kg/cm to obtain a matte coated paper for gravure printing. As a quality test method for the matte coated paper for gravure printing obtained in this way, halftone dot reproducibility called misdot was measured using J, TAP.
PI paper pulp test method, No. 24 m r paper gravure printing suitability test method (Printing Bureau type)", and the resulting prints were evaluated visually and by enlarged photographs, and the results are shown in Table 3.

Comparative Example 9 In the process of obtaining recycled pulp, the pulp concentration in the kneader was set to 10% and the resulting recycled pulp 10
%, 50% NBKP, 15% LBKP, and 25% 5GP. To this pulp, 0.05% rosin size, 2% band sulfate, and 10% talc as a filler were added to the pulp. Wetting value] Dynamic wettability tester (WET-3000/manufactured by Resca)
It was measured by Measured value 2 seconds after immersion in water. The larger the value, the easier it is to wet (unit: g).

[Specular reflection type smoothness]

Using a specular reflection type smoothness meter manufactured by Toyo Seiki, the measurement pressure was 20.
Measured at Kg 7cm2. The larger the number, the better the smoothness (unit: %).

[Smoothness]

Measurement was performed using a Smoostar smoothness meter DSM01 manufactured by Toei Denshi ■. The smaller the number, the better the smoothness (cm Hg)
.

[Printing (surface) strength]

Printing was performed at a speed of 5000 sheets/min using an offset four-color printing machine, and the surface of the printed matter was visually observed and evaluated.

○; Good.

×: Partial lifting or peeling of the coating layer was observed, making it defective.

[Print smoothing]

8 The printed matter used for the above evaluation of printed surface strength was visually observed, and the smoothness of the printed surface was visually evaluated.

◎; The smoothness of the printed surface is very good.

○: Good smoothness of the printed surface.

×: The smoothness of the printed surface decreased and deteriorated.

[Gravure suitability]

J, TAPPI Paper Valve Test Method, No. 24 m
Printing was carried out using the "Gravure Printing Suitability Test Method for R Paper (Printing Bureau Method)" and the resulting printed matter was relatively evaluated by visual inspection and enlarged photographs.

◎: Excellent ○: Average ×: Many halftone misdots and poor “effect” As is clear from the results in Table-1, Table-2, and Table-3,
The coated paper containing pulp recycled by the HD K method obtained by the method of the present invention is a coated paper for printing that has improved smoothness of the coated layer surface and has extremely excellent blank paper quality and printing quality. there were.

Claims (4)

[Claims] (1) In a method for producing coated paper for printing, in which a coating composition containing pigments and adhesives as main components is applied onto a base paper, dried, and then calendered, a pulp component is added to the base paper under the following conditions. The waste paper recycled pulp to be produced is contained in an amount of 3% by weight or more, and the dynamic wettability value of the base paper is -0.32 to +0.
15 g, and the surface smoothness of the base paper as measured by a specular reflection smoothness meter under a pressure of 20 Kg/cm^2 is 12% or more. [Conditions for producing recycled pulp from used paper] "Recycled pulp from used paper obtained through a deinking process that includes a mechanical stirring process that imparts compressive force to waste paper in the presence of a surfactant-based deinking agent." (2) The method for producing a coated paper for printing according to claim (1), wherein the base paper has a dynamic wettability value of -0.30 to +0.10 g. (3) The method for producing coated paper for printing according to claim (1) or (2), wherein the pulp composition constituting the base paper contains 20% by weight or less of high-yield pulp. (4) The method for producing coated paper for printing according to claim (1) or (2), wherein the pulp composition constituting the base paper contains 10% by weight or less of high-yield pulp.