JPH0441797A - Coated paper for printing - Google Patents

Abstract

PURPOSE:To obtain the title coated paper having excellent light resistance and high whiteness, effectively utilizing old paper of a pressure-sensitive duplicating paper by adding a specific compound to a regenerated pulp slurry of the pressure-sensitive duplicating paper, making the slurry into paper to give a base paper and forming a coated layer on the base paper. CONSTITUTION:(A) An amine compound and/or a quaternary ammonium salt compound is added to a stage of regenerated pulping of old paper of a pressure- sensitive duplicating paper or a prepared pulp slurry of regenerated pulp, which is made into paper to give a base paper. The base paper is provided with a coated layer containing (B) alkaline pigment to give the objective coated paper. The base paper preferably comprises 5-95wt.% old paper of the pressure-sensitive duplicating paper, 0.05-10wt.% component A and >=5wt.% component B.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a coated paper for printing that uses waste paper, and in particular, a coated paper for printing that effectively utilizes waste paper of pressure-sensitive copying paper and has good light resistance. It is related to.

[Conventional technology]

Generally, coated paper for printing is manufactured by coating a base paper obtained by paper-making pulp fibers with a coating composition containing a pigment and an adhesive as main components, drying it, and then finishing it with a super calender.

The base paper for coated paper for printing is made by beating so-called virgin pulp, which is obtained by chemically bleaching pulp obtained by chemically, mechanically, biochemically or semi-mechanically treating wood. A base paper obtained by adding filler, sizing agent, fixing agent, dye, etc. to pulp slurry and making paper is used. In this papermaking process, the surface of the paper is often treated with an adhesive in order to increase its surface strength.

Coated paper for printing obtained using such base paper can be printed by lithographic printing, letterpress printing, flexo printing, gravure printing, etc., and can be used for calendars, posters, magazines, etc.
Although it is used in a wide range of fields such as books, leaflet advertisements, and catalogs, it is generally prone to photofading (yellowing), and improvements in this problem are desired.

In addition, the demand for paper continues to increase as the economy develops. For this reason, in recent years, from the perspective of effective resource utilization, there has been an increasing trend toward converting waste paper into recycled pulp and its effective use.

Currently, the amount of used paper used in Japan exceeds 50x of the raw material for paper and paperboard production, and there is a growing demand for recycling even more used paper from the standpoint of effective resource utilization.

Waste paper that can be made into recycled pulp includes newspapers, cardboard, magazines, imitations, colored clay (including art), white paper, cards, special white paper,
White inside, white manila, cut out, old middle aged, brown imitation paper (including floating), mount, ground certificate, ball, thermal paper, pressure sensitive copying paper, C,
P, 0. etc.

In general, the method for recycling and pulping used pressure-sensitive copy paper from these used papers is to disintegrate the used paper in an alkaline solution,
Disintegration process to obtain a pulp suspension, rough selection and separation to separate foreign substances
A method of regenerating pulp through a selection process, a flocheater process to separate the microcapsules containing the dye and the color developer into foam, a washing process to wash the microcapsules containing the dye and the color developer, a bleaching process to whiten the color, etc. is taken.

Since the recycled pulping method for waste pressure-sensitive copying paper requires a very complicated process as described above, the use of waste pressure-sensitive copying paper is still only partially used.

[Problem to be solved by the invention]

The present invention relates to coated paper for printing using waste paper, and in particular, an object of the present invention is to provide coated paper for printing with good light resistance by effectively utilizing recycled pulp from waste paper for pressure-sensitive copying paper. It is.

[Means to solve problems]

The present invention provides an alkaline pigment to base paper made by adding an amine compound and/or a quaternary ammonium salt compound to the recycled pulping stage of used pressure-sensitive copying paper or to the pulp slurry containing the obtained recycled pulp. A coated paper for printing characterized by forming a coating layer containing:

[Effect]

In the present invention, the recycled pulp contained in the base paper is recycled pressure-sensitive copying paper, and this pressure-sensitive copying paper contains microcapsules containing an electron-donating dye on one side of the base paper. "Top paper" coated with a layer, "Bottom paper" coated with a layer containing an electron-accepting compound (developer) that develops color upon contact with electron donating properties, and a layer containing microcapsules on one side of the base paper. ``Medium paper'' which is coated with a layer containing a color developer on the other side, and ``self-coloring paper'' where a color developer such as microcapsules is layered or mixed on the same side of the base paper are known. , used paper made by appropriately combining them, and semi-finished products and horizontal paper generated in the process of manufacturing these pressure-sensitive copying papers.

When disintegrating the pressure-sensitive copy paper used above, it is best to use an alkaline aqueous solution to accelerate disintegration. Examples of alkaline agents include sodium hydroxide, potassium hydroxide, calcium hydroxide, sodium silicate, and sodium carbonate. ,
Examples include potassium carbonate, sodium hypochlorite, calcium hypochlorite, and the like. Among these, hypochlorite is particularly effective and preferred for used paper that has already developed a color, since it promotes disintegration and oxidizes and decomposes dyes and bleaches them.

Furthermore, when disintegrating waste pressure-sensitive copying paper, it often contains foreign substances such as plastics and adhesives, which may be broken into small pieces by an agitator or the like during disintegration, which may impair the separation effect in the sorting process. . Therefore, it is preferable to adjust the degree of disaggregation.

If the foreign matter is crushed into small pieces by a stirrer, etc.,
Not only does the separation effect in the screening process deteriorate, but when paper is made using recycled pulp, the pressure-sensitive adhesive can block the wire openings during the paper-making process, stain press rolls and blankets, cause paper breakage, and reduce paper-making efficiency. A problem arises in that the Further, there is a problem that spots are formed on the paper surface, which adversely affects the formation of the paper layer or the quality of the paper. The degree of disintegration can be adjusted by adjusting the length of disintegration time, pulp concentration, water temperature,
It may be adjusted by adjusting the amount of alkali added, etc., and is not particularly limited.

The recycled pulp slurry of pressure-sensitive copying paper waste thus obtained is further sent to a screening process, where it is screened to separate foreign substances. Incidentally, if a rough screening step is provided above the fine selection step, large foreign substances can be removed in the rough screening step before proceeding to the fine selection step, and clogging of the screen in the fine selection step can be prevented.

In the present invention, the recycled pulp of used pressure-sensitive copying paper obtained by the disintegration treatment as described above is used by blending it with other pulp, such as so-called virgin pulp. The base paper obtained by blending this recycled pulp with virgin pulp and making paper has low tension and good smoothness. Preferably 10
It is desirable to contain it in a range of 90% by weight. Incidentally, if it is less than 5% by weight, the desired effect will not be sufficient, and if it is more than 95% by weight, it will be difficult to obtain a base paper with excellent paper strength even if it is used in combination with softwood virgin pulp. Also,
If this recycled pulp is used without beating, base paper with sufficient paper strength cannot be obtained. For this reason, it is desirable to treat it with a beating machine in the previous process of the paper machine. In the case of beating treatment, this recycled pulp may be treated alone,
It is also good to mix it with gin pulp and beat it together.

The degree of beating may be appropriately selected depending on the amount of recycled pulp blended, the type of paper machine, the physical properties of the coating composition, the type of coater, the required quality of the product, etc.

As the refining machine, a conical refiner, a single refiner, a double disc refiner, etc. are used, but in consideration of power, it is more preferable to use a double disc refiner.

Therefore, in the present invention, an amine compound and/or a quaternary ammonium salt compound is added to the stage of converting waste pressure-sensitive copying paper into a recycled pulp or to the pulp slurry containing the obtained recycled pulp. An important requirement is to use certified base paper.

By the way, if recycled pulp from pressure-sensitive copying paper is used as is, the remaining microcapsules will be destroyed by the pressure during the smoothing process in the paper machine's calender or the super calender after the coater, and they will react with the color developer. This results in coloring and lowering the product value.

When an amine compound and/or a quaternary ammonium salt compound is added to the recycled pulping stage of pressure-sensitive copying paper waste paper and/or to the pulp slurry containing the obtained recycled pulp, these compounds become electron-donating dyes. This prevents the contact reaction between the electron-accepting compound (color developer) and the color development.

The amine compounds and/or quaternary ammonium salt compounds used in the present invention include aliphatic amine salts, aliphatic quaternary ammonium salts, benzalkonium salts, benzethonium chloride, pyridinium salts, imidazolinium salts, carboxybetaine type, Examples include cationic surfactants such as aminocarboxylate salts and amphoteric surfactants. Furthermore, cation-modified starch, cation-modified latex, cation-modified polyvinyl alcohol, cation-modified vegetable gum, polyethyleneimine, polyamine, polyamide/polyamine, polyacrylamide, urea-formalin resin, melamine-formalin resin, polyamide resin, etc. generally have low yields. Some of those used as improvers and paper strength enhancers are also effective.

The specific substance of the amine compound and/or quaternary ammonium salt compound to be used varies depending on the type and amount of the electron-donating dye and the electron-accepting substance (developer), so they should be selected and used as appropriate. Become. An effective amount of addition is 0.05 to 10% by weight based on the dry pulp.

It is effective to add the amine compound and/or the quaternary ammonium salt compound at the regenerated pulping stage or into the pulp slurry containing the obtained regenerated pulp before paper making.

Paper making from pulp slurry to which an amine compound and/or quaternary ammonium salt compound has been added may be made using either normal acidic papermaking or neutral papermaking, but in consideration of waste paper recovery and light resistance, neutral papermaking is preferred. is preferable. In the case of neutral papermaking, calcium carbonate is added as a filler to lower the papermaking pH to 6.
- Adjust to 9 and make paper. When the pH is lower than 6, the solubility of calcium carbonate increases and the yield during papermaking becomes poor. Moreover, when the pH becomes 9 or more, alkaline burning of the pulp occurs, and the whiteness decreases.

In addition to calcium carbonate, fillers that are generally known and used in the paper industry, such as talc, kaolin, clay,
Mineral fillers such as calcined kaolin, delamic kaolin, titanium dioxide, calcium sulfate, calcium hydroxide, aluminum hydroxide, zinc hydroxide, magnesium hydroxide, magnesium carbonate, magnesium sulfate, magnesium silicate, white carbon, bentonite, and polystyrene resin fine particles. , urea-formalin resin fine particles, organic synthetic fillers such as fine hollow particles, etc. are also appropriately selected and used in combination. Furthermore, fillers contained in waste paper, blocks, etc. can also be used effectively.

Internal additives for papermaking include various conventionally used anionic, nonionic, cationic, or amphoteric retention aids, freeness improvers, paper strength enhancers, sizing agents, etc. , alkyl ketene dimer sizing agents, alkenyl succinic anhydride sizing agents, styrene-acrylic sizing agents, stearic anhydride sizing agents, petroleum resin sizing agents, rosin sizing agents, various starches, polyesters, etc. Organic compounds such as acrylamide, polyethyleneimine, polyamine, polyamide/polyamine, vegetable gum, urea-formalin resin, melamine-formalin resin, polyvinyl alcohol, latex, polyethylene oxide, polyamide resin, derivatives or modified products thereof, or aluminum sulfate, etc. water-soluble aluminum salt of
Inorganic compounds such as colloidal silica and bentonite are used alone or in appropriate combinations of two or more, and dyes, pH adjusters, antifoaming agents, pitch control agents,
Internal additives for papermaking, such as slime control agents, are added as appropriate depending on the purpose of the paper.

As the paper machine, commonly used fourdrinier paper machines, twin wire paper machines, circular wire paper machines, etc. can be used.

A multi-barrel dryer or a Yankee dryer can be used in the drying section of the paper machine.

In the present invention, a coating layer containing a pigment and an adhesive as main components is formed on the base paper thus obtained, but the present invention requires the formation of a coating layer containing an alkaline pigment. The reason why it is required is that, as mentioned above, the base paper has
An amine compound and/or a quaternary ammonium salt compound are added to the recycled pulping stage of pressure-sensitive copy paper waste paper and/or to the pulp slurry containing the obtained recycled pulp to prevent coloring. If a coating layer consisting only of non-alkaline pigments such as kaolin or clay is formed on such base paper, the whiteness and light resistance of the coated paper will deteriorate, resulting in a decrease in commercial value.

On the other hand, the alkaline pigment in the coating layer accounts for 5% of the total pigment.
By containing more than % by weight, the whiteness of the coated paper is improved, the light resistance is also improved, and a coated paper with excellent printability can be obtained.

Examples of the alkali pigment include heavy calcium carbonate, light calcium carbonate, satin white, aluminum hydroxide, and magnesium carbonate.

These alkaline pigments have high whiteness, and when a coating composition containing these pigments is provided on base paper, a coated paper with high whiteness can be obtained. Among these, sachinshiro, heavy calcium carbonate, light calcium carbonate, etc. are preferable.

The content of these pigments is preferably 5% by weight or more based on the solid weight of the total pigment in order to obtain the above effects, and preferably 10% by weight or more in order to obtain more effects.

Examples of adhesives include proteins such as casein, soybean protein, and synthetic proteins; conjugated diene copolymer latex such as styrene/butadiene copolymer, methyl methacrylate/butadiene copolymer, and acrylic ester and/or methacrylic acid. Acrylic polymer latex such as ester polymer or copolymer, vinyl polymer latex of ethylene/vinyl acetate polymer, or various polymer latexes modified with monomers containing functional groups such as carboxyl groups. Various synthetic resin polymers called alkali-soluble, alkali-swellable, or alkali-insoluble polymer latex and binder pigment; synthetic resin adhesives such as polyvinyl alcohol, olefin, maleic anhydride resin, melamine resin, oxidized starch , starches such as positive starch, esterified starch, and dextrin; and cellulose derivatives such as carboxymethyl cellulose and hydroxycellulose. One or more types of common adhesives for coated paper are appropriately selected and used.

Generally, the adhesive is used in an amount of 4 to 50 parts by weight per 100 parts by weight of the pigment.
It is blended in an amount of about 10 to 30 parts by weight, more preferably about 10 to 30 parts by weight. Various auxiliaries such as antifoaming agents, coloring agents, mold release agents, flow modifiers, preservatives, etc. are appropriately blended into the coating liquid as necessary. For example, amine, amide, polyacrylamine, etc., or a salt of a polyvalent metal such as zinc, aluminum, magnesium, calcium, barium, etc., is added in an amount of 0.1 to 10% per 100 parts by weight of the pigment.
Parts by weight may be added.

The coating liquid can be applied to a blade coater, an air knife coater, a roll coater, etc., which are used in general coated paper manufacturing.
One layer or multiple layers can be coated on base paper using an on-machine or off-machine coater equipped with double-sided or single-sided coating equipment such as a reverse coater, bill blade coater, curtain coater, die slot coater, gravure coater, chambrex coater, size press coater, etc. coated. The solid content concentration at that time is generally about 40 to 75% by weight, but in consideration of operability, a range of 45 to 70% by weight is preferable. The amount of coating liquid applied to the base paper is generally about 3 to 50 g/bo on dry weight per side, but when considering the whiteness, light resistance, and printability of the resulting coated paper, it is about 5 to 4 g per side.
A range of about 0 g/rrf is preferable.

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

The coated paper thus obtained has excellent light resistance and printability.

〔Example〕

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

Note that parts and % in the examples indicate parts by weight and % by weight, respectively, unless otherwise specified.

Example 1 <Preparation of base paper> A pulper was charged with pressure-sensitive copying paper waste and water so that the pulp concentration was 5%, and 2% sodium hydroxide solution was added to the waste paper and disintegrated for 30 minutes. .

This suspension was adjusted to a pulp concentration of 3.5%, and was carefully selected using a screen with a slit width of 0.5 mm (CH type high-density screen manufactured by Soyo Iron Works Co., Ltd.).

To this accepted pulp, polyethyleneimine (manufactured by BASF; Polymin SK) was added as an amine compound in an amount of 1% based on the dry pulp, and the pulp was beaten with a double desfret refiner to obtain a recycled pulp with a freeness of 400 ml. Four parts of this recycled pulp were each beaten to a freeness of 500ml, and to a pulp slurry prepared by blending 90 parts of BKP and 6 parts of NBKP, heavy calcium carbonate was added so that the ash content was 10%, and sulfate band 0.5%, cationic starch [manufactured by Tamago National ■; product name 0NL-4
In addition, 0.1% of alkyl ketene dimer (manufactured by Dick Bercules; trade name: Burcon) and 0.1% of cationic polyacrylamide (manufactured by Allied Colloids; trade name: Percoll 155) were added as sizing agents.
0.05% was added and mixed to adjust.

The pulp slurry thus prepared was made into paper using a fourdrinier cylinder dryer paper machine, and the oxidized starch was added to 2 g/rr.
Size press to make f, basis weight 64g/rrI
A coated base paper was obtained.

<Preparation of coating composition> 80 parts of kaolin [manufactured by EMC; trade name 1UW-90],
10 parts of heavy calcium carbonate (manufactured by Bihoku Funka Kogyo ■; trade name: Softon 1800), 10 parts of Satin White, 0.1 part of sodium hydroxide, and 0.3 part of sodium polyacrylate were placed in a Coles disperser and dispersed. , furthermore, 5 parts of oxidized starch,
Add 13 parts of styrene-butadiene latex and 0.05 part of a silicone antifoaming agent, stir and mix to obtain a solid concentration of 6.
A 0% coating solution was prepared.

<Coating> The coating composition obtained as described above was coated on both sides of the base paper using a blade coater so that the dry weight was 20 g/rrf per side, dried with a dryer, and coated with a super calender. Pressure treatment was performed to obtain double-sided coated paper.

The quality of the thus obtained coated paper was evaluated and the results are shown in Table 1.

Example 2 <Preparation of base paper> A pulper was charged with pressure-sensitive copy paper waste paper and water so that the pulp concentration was 5%, and a sodium hypochlorite solution was added to the waste paper in an amount of 1% based on the waste paper. and disintegrated for 30 minutes.

This suspension was adjusted to a pulp concentration of 3.5% and carefully selected using a screen with a slit width of 0.5 mm (CO type high concentration screen manufactured by Aiyo Tekko ■).

This accepted pulp was coated with cationic polyacrylamide [manufactured by Kurita Kogyo ■; product name: Kurifix CP-662].
) was added to the dry pulp in an amount of 1%, and the mixture was beaten in a double despray refiner to obtain recycled pulp with a freeness of 400 ml. 10 parts of this recycled pulp, 80 parts of LBKP, 80 parts of NB, each beaten to a freeness of 500ml.
To the pulp suspension prepared by blending the KPIO part, heavy calcium carbonate was added so that the paper ash content was 10%, and 0.5% of sulfate and cationic starch [manufactured by Tamago National ■; product name 1ONL-400] were added. ) 0.5%, and further 0.1% of alkyl ketene dimer [manufactured by Dick Bercules ■; trade name: Burcon] as a sizing agent.
, 0.05% of cationic polyacrylamide (manufactured by Allied Colloid Co., Ltd.; trade name: Percoll 155) was added.

The pulp slurry thus prepared was made into paper using a long-length multi-cylinder cylinder dryer paper machine, and the oxidized starch was added to 2 g/nf.
A coated paper base paper having a basis weight of 64 g/rrf was obtained by size pressing so that the following was obtained.

<Preparation of coating composition> Kaolin [manufactured by EMC; trade name; UW-90: 170 parts; heavy calcium carbonate [manufactured by Bihoku Funka Kogyo ■; trade name; Softon 1800] 10 parts; Satin White 10 parts and water. 0.1 part of sodium oxide and 0.3 part of sodium polyacrylate were placed in a Coles disperser and dispersed, and further 5 parts of oxidized starch,
Add 13 parts of styrene-butadiene latex and 0.05 part of a silicone antifoaming agent, stir and mix to obtain a solid concentration of 6.
A 0% coating solution was prepared.

<Coating> The coating composition obtained as described above was coated on both sides of the base paper using a blade coater at a dry weight of 20 g/I per side, dried with a dryer, and coated with a super calender. Pressure treatment was performed to obtain double-sided coated paper.

The quality of the thus obtained coated paper was evaluated and the results are shown in Table 1.

Example 3 <Preparation of base paper> A pulper was charged with pressure-sensitive copy paper waste paper and water so that the pulp concentration was 5%, and a sodium hypochlorite solution was added to the waste paper in an amount of 1% based on the waste paper. and disintegrated for 30 minutes.

This pulp slurry was adjusted to a pulp concentration of 3.5%,
Selection was made using a screen with a slit width of 0.5 m (CH type high concentration screen manufactured by Aiyo Tekko ■).

This accepted pulp was coated with cationic polyacrylamide [manufactured by Kurita Kogyo ■; product name: Kurifix CP-662].
1 was added to the dry pulp in an amount of 1%, and the mixture was beaten in a double despray refiner to obtain a recycled pulp with a freeness of 400 ml. 30 parts of this recycled pulp, 60 parts of LBKP and NB, each beaten to a freeness of 500 m1.
To the pulp suspension prepared by blending the KPIO part, heavy calcium carbonate was added so that the paper ash content was 10%, and 0.5% of sulfate and polyacrylamide (manufactured by Ayu Kagaku ■; trade name: KW677) were added. .5% and further alkyl ketene dimer [Arayo Kagaku ■] as a sizing agent.
0.1% of 5PK-902, manufactured by Allied Colloid Co., Ltd., and 0.05% of cationic polyacrylamide (trade name, Percoll 155, manufactured by Allied Colloid Co., Ltd.) were added.

The thus prepared pulp slurry was made into paper using a Fourdrinier multi-tube cylinder dryer paper machine to obtain a base paper for coated paper having a basis weight of 65 g/cm2.

<Preparation of coating composition> 50 parts of kaolin (manufactured by EMC; trade name: UW-90),
30 parts of heavy calcium carbonate (manufactured by Bihoku Funka Kogyo, trade name: Softon 1800), 20 parts of Sachin White, 0.1 part of sodium hydroxide, and 0.3 part of sodium polyacrylate were placed in a Coles disperser and dispersed. Furthermore, 5 parts of oxidized starch, 13 parts of styrene-butadiene latex, and 0.05 part of silicone antifoaming agent were added and mixed with stirring until the solid concentration was 60.
% coating solution was prepared.

<Coating> The coating composition obtained as described above was coated on both sides of the base paper using a blade coater at a dry weight of 20 g/if per side, dried with a dryer, and coated with a super calender. Pressure treatment was performed to obtain double-sided coated paper.

The quality of the thus obtained coated paper was evaluated and the results are shown in Table 1.

Example 4 <Preparation of base paper> A pulper was charged with pressure-sensitive copy paper waste paper and water so that the pulp concentration was 5%, and a sodium hypochlorite solution was added to the waste paper in an amount of 1% based on the waste paper. and disintegrated for 30 minutes.

This pulp slurry was adjusted to a pulp concentration of 3.5%,
Careful selection was performed using a screen with a slit width of 0.5 mm (C8 type high-density screen manufactured by Aiyo Tekko ■).

A cationic surfactant [Kao ■] is added to this accepted pulp.
Product name: Koutamine 24P] was added at 1% to the dry pulp, and the pulp was beaten with a double desfretfiner.
Regenerated pulp with a freeness of 400 ml was obtained. To a pulp suspension prepared by blending 60 parts of this recycled pulp with 30 parts of LBKP and NBKPIO parts each beaten to a freeness of 500 ml, heavy calcium carbonate was added so that the ash content was 10%, and sulfate band 0 was added. .5
%, polyacrylamide [manufactured by Arayo Kagaku ■; product name; KW
677) 0.7% and further alkyl ketene dimer [manufactured by Aurayo Kagaku ■; trade name; 5PK-] as a sizing agent.
902) 0.1%, cationic polyacrylamide (manufactured by Allied Colloid; trade name: Percoll 155) 0.
05% was added.

The thus prepared pulp slurry was made into paper using a Fourdrinier multi-tube cylinder dryer paper machine to obtain a base paper for coated paper having a basis weight of 65 g/-2.

<Preparation of coating composition> 30 parts of kaolin [manufactured by EMC; trade name: UW-90],
40 parts of heavy calcium carbonate (manufactured by Bihoku Funka Kogyo, trade name: Softon 1800), 30 parts of Satin White, 0.1 part of sodium hydroxide, and 0.3 part of sodium polyacrylate were placed in a Coles disperser and dispersed. Further, 5 parts of oxidized starch, 13 parts of styrene-butadiene latex, and 0.05 part of silicone antifoaming agent were added, and the mixture was stirred and mixed until the solid concentration was 60.
% coating solution was prepared.

<Coating> The coating composition obtained as described above was coated on both sides of the base paper using a blade coater so that the dry weight was 20 g/rrf per side, dried with a dryer, and coated with a super calender. Pressure treatment was performed to obtain double-sided coated paper.

The quality of the thus obtained coated paper was evaluated and the results are shown in Table 1.

Comparative Example 1 <Preparation of base paper> A pulper was charged with waste pressure-sensitive copying paper and water so that the pulp concentration was 5%, and disintegrated for 30 minutes.

This pulp slurry was adjusted to a pulp concentration of 3.5%,
Screen with a slit width of 0.5 m (CH manufactured by Aiyo Iron Works)
The products were carefully selected using a high-density screen (type high-density screen).

This accepted pulp was beaten with a double desfret refiner to obtain recycled pulp with a freeness of 400 ml. 10 parts of this recycled pulp, each with a freeness of 500m
Pulp suspension benzidine prepared by blending 30 parts of LBKP and 10 parts of NBKP, which have been beaten into 1, has a low ash content of 10.
% of talc, then 0.5% of rosin sizing agent and 3% of sulfuric acid were added.

The thus prepared pulp slurry was made into paper using a long-length multi-tube cylinder dryer paper machine, and the oxidized starch was added to 2 g/m".
A base paper for coated paper having a basis weight of 65 g/w'' was obtained by size pressing.

<Preparation of coating composition> Kaolin manufactured by CEMC; trade name: UW-90) 80 parts;
10 parts of heavy calcium carbonate (manufactured by Bihoku Funka Kogyo, trade name: Softon 1800), 10 parts of Sachin White, 0.1 part of sodium hydroxide, and 0.3 part of sodium polyacrylate were placed in a Coles disperser and dispersed. Furthermore, 5 parts of oxidized starch, 13 parts of styrene-butadiene latex, and 0.05 part of silicone-based defoaming side were added and mixed with stirring until the solid concentration was 60.
% coating solution was prepared.

Coating> The coating composition obtained as described above was coated on both sides of the base paper using a blade coater so that the dry weight was 20 g #rf per side, dried with a dryer, and coated with a super calender. Pressure treatment was performed to obtain double-sided coated paper.

The quality of the thus obtained coated paper was evaluated and the results are shown in Table 1.

Comparative Example 2 <Preparation of Base Paper> In the same manner as in Example 1, coated Kawabase paper with a basis weight of 65 g/m'' was obtained.

<Preparation of Coating Composition> A coating liquid with a solid concentration of 60% was prepared in the same manner as in Example 1, except that 100 parts of kaolin (manufactured by EMC Corporation, UW-90) was used as the pigment.

<Coating> The coating composition obtained as described above was coated on both sides of the base paper using a blade coater to give a dry weight of 20 g/rd per side, dried with a dryer, and coated with a super calender. Pressure treatment was performed to obtain double-sided coated paper.

The quality of the thus obtained coated paper was evaluated and the results are shown in Table 1.

〔effect〕

As is clear from the results in Table 1, the coated paper for printing obtained in each Example of the present invention had high whiteness and was transparent and light-fast.

Claims (5)

[Claims] (1) An alkaline pigment is contained in the base paper made by adding an amine compound and/or a quaternary ammonium salt compound to the recycled pulping stage of used pressure-sensitive copying paper or to the pulp slurry containing the obtained recycled pulp. A coated paper for printing characterized by forming a coating layer. (2) 5 to 95% recycled pulp from pressure-sensitive copying paper used in the base paper
The coated paper for printing according to claim 1, characterized in that it contains % by weight. (3) The coated paper for printing according to claim (1), wherein the base paper is made by adding 0.05 to 10% by weight of an amine compound and/or a quaternary ammonium salt compound. (4) The coated paper for printing according to claim (1), characterized in that the coating layer contains 5% by weight or more of an alkaline pigment in all the pigments. (5) Base paper hot water extraction pH (JISP8133) is 6~
9. The coated paper for printing according to claim 1, wherein the coated paper is 9.