JP2770840B2 - Base paper for coated paper for gravure printing - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001] The present invention is used for producing coated paper for printing, in which a coating liquid containing a pigment and an adhesive as a main component is coated on one or both sides of base paper made of cellulose pulp using a coater. Regarding the base paper, more specifically, it has excellent ink deposition property and coater operability during gravure printing.
The present invention relates to base paper for producing coated paper for gravure printing.

[0002]

2. Description of the Related Art Base paper for coated paper for printing (hereinafter, simply referred to as "coated base paper") is made from lignocellulosic material, especially cellulose pulp (hereinafter, simply referred to as "pulp") made from wood chips. ing. However, in recent years, protection of forest resources has been promoted from the viewpoint of global environmental protection, and therefore, recycled pulp, that is, deinked waste paper pulp (DIP)
The use of deinked pulp is also being promoted in coated base paper.

[0003] Waste paper used as a raw material of deinked waste paper pulp is roughly classified into cardboard waste paper, high quality waste paper, and newspaper magazine waste paper. The waste paper for deinked waste paper pulp used in the production of coated base paper is of high quality. Waste paper and newspaper / magazine waste paper are used. Many techniques for pulping such waste paper, removing ink (deinking), removing foreign matter, and further adjusting the whiteness to a desired level have already been reported. For example, "Handbook of Waste Paper" (edited by Paper Science Research Institute, Showa Published April 25, 1986, 65-2
52).

[0004] Pulp constituting deinked waste paper pulp mainly consists of chemical pulp and mechanical pulp obtained by an alkaline cooking method. The freeness (CSF, the same applies hereinafter) of the deinked waste paper pulp after adjusting the whiteness varies depending on the type of paper contained in the waste paper, but is usually 150 to 400 ml.

[0005]

When such deinked waste paper pulp is used as a part of the raw material pulp of the coated base paper, the Bekk smoothness and the center line average roughness of the coated base paper (see "Papermaking Science"). The Chugai Industrial Research Council, published June 25, 1982, pp. 684-685) can obtain coated base paper within a certain standard, but it is possible to obtain clumps and removal of small fibers mixed in deinked waste paper pulp. Fine black clumps of hardened foreign substances and adhesives such as gum tape are made into the coated base paper, and the inlaid part slightly protrudes from the surface of the coated base paper Sometimes. In the past, machine calender processing was strengthened to remove this slight surface protrusion on the coated base paper.However, not all small protrusions were crushed. When the coating liquid is applied with a coater, fine blisters remain on the coating surface. For this reason, the fine blisters cause poor gravure printing ink deposition,
The product value of coated paper for printing was reduced. Many techniques have been proposed to improve the inking property of gravure printing ink on coated paper for printing.However, there are many techniques mainly on the composition of the coating solution and the physical properties of the coating layer. No technique has been proposed to reduce the minute protrusions on the surface of a coated base paper containing the above to improve the gravure printing ink adhesion of coated paper.

On the other hand, coated base paper containing deinked waste paper pulp is
The penetration rate of the aqueous adhesive solution contained in the coating liquid into the base paper for coating varies depending on the content of the deinked waste paper pulp and the freeness of the deinked waste paper pulp. As a result, after the coating liquid is applied to the coating base paper by the coater, phenomena such as wrinkling and breakage of the coated paper are observed. Fluctuations in the operation of the coater has been a factor.

As a technique focusing on the penetration rate of water (aqueous solution) into coated base paper, for example, the dynamic wetting value of the coated base paper is specified to improve the stiffness and glossiness of the coated paper. A technique (Japanese Patent Application Laid-Open No. 3-199491) has been proposed, but the relationship between the penetration rate of water (aqueous solution) into the coated base paper and the operability in a coater is clarified for the coated base paper containing deinked waste paper pulp. No such technique has been proposed so far.

As described above, when the deinked waste paper pulp is used as a part of the raw material pulp of the coated base paper, the aforementioned defects as the coated base paper are conspicuous, and the deinked waste paper pulp is sufficiently satisfied with the coated base paper. Had not been used.

Therefore, the present invention is excellent in operability with a coater because even a coated base paper containing deinked waste paper pulp is less wrinkled or cut when coated with a coating liquid. The purpose of the present invention is to provide a base paper for printing coated paper, wherein the coated paper for printing has excellent gravure printing ink inking property.

[0010]

Means for Solving the Problems In order to solve the above-mentioned problems, the present inventors have developed a technique for reducing minute protrusions on the surface of a coated base paper containing deinked waste paper pulp, and a method for reducing water on the coated base paper. As a result of studying the relationship between the permeation rate of (aqueous solution) and the occurrence of wrinkles and paper breaks when applying a coating liquid with a coater, the deinked waste paper pulp is included in deinked waste paper pulp by beating it to a specific freeness value. Because the small fiber clumps and foreign matter that could not be removed are crushed or torn, the coated base paper using the deinked waste paper pulp that has been beaten in this way has reduced fine protrusions on its surface. To do,
In addition, the coating liquid is applied to the coated base paper by a coater by adjusting the penetration rate (water absorption) of water (aqueous solution) of the coated base paper including the beaten-treated deinked waste paper pulp to a specific range. It has been found that the occurrence of wrinkles and breaks in the later coated paper is reduced, and the present invention has been completed.

That is, the present invention relates to a base paper for coated paper for gravure printing, wherein 5-80% by weight (absolutely dry) of the pulp component constituting the base paper is adjusted to a freeness of 50-250 ml by beating. A base paper for coated paper for gravure printing, characterized in that the base paper is made of used deinked waste paper pulp, and the transfer length of the base paper by the Bristow method is adjusted to 10 to 50 cm.

As used herein, the term "transition length of a liquid by the Bristow method" refers to the Bristow method for measuring the wetting of a liquid on a paper surface in a short time and the subsequent permeation behavior into the paper.
(Bristow's Method), in which the transition length of the liquid transferred to the test piece is expressed in cm. Tappi No. 51-87. The measuring device used was a Bristow test machine type II (pressurized type) (manufactured by Kumagai Riki Co., Ltd.).
The peripheral speed of the disk was kept constant at 25.0 mm / sec, and distilled water (malachite green 0.1% coloring) was used as the liquid.

As the raw material used for the deinked waste paper pulp used as the raw material for the coated base paper of the present invention, it is generally preferable to use 50 to 95% of newspaper and magazine waste paper and 5 to 50% of high quality waste paper. . The deinked waste paper pulp is a recycled pulp obtained by defibrating this waste paper by a known device, removing foreign matter, deinking and bleaching, and usually has a whiteness of 50 to 50%.
Adjusted to 75%. The conditioned deinked waste paper pulp has a freeness of 150-400 ml.

In the present invention, the deinked waste paper pulp is beaten to break up clumps of mixed fibers and foreign matters that cannot be completely removed. When beating deinked waste paper pulp, if the drop in freeness is less than 40 ml, clumps of fibers and foreign matter will not be effectively cracked, and if the drop in freeness is more than 150 ml, the short fibers of the deinked waste paper pulp will increase. Pulp quality is reduced. When the freeness of the deinked waste paper pulp constituting the coated base paper of the present invention is less than 50 ml, the drainage of the wire part becomes poor when the coated base paper is made, and the production amount of the coated base paper is reduced. If the freeness of the deinked waste paper pulp exceeds 250 ml, there is a high possibility that foreign materials are not effectively cracked.

[0015] In order to break up clumps of fibers and foreign substances contained in unbeaten deinked waste paper pulp by beating, it is advantageous to carry out beating with a strong cutting tendency. From such a viewpoint, it is preferable to perform the beating process using a double desk refiner or a deluxe finer.

As described above, it is advantageous to perform beating with a strong cutting tendency in order to break up clumps of fibers and foreign substances contained in the deinked waste paper pulp by beating. Pulp quality is reduced due to a decrease in the proportion of long fibers. Therefore, it is preferred in the present invention that the beating is performed to such an extent that the long fibers do not excessively decrease after the beating and the pulp quality does not significantly deteriorate. Accordingly, the present inventors have further studied the degree of beating of deinked waste paper pulp, and as a result, a pulp screening test (JIS)
P8207), the relationship between the ratio of the total pulp content of the remaining 150 mesh and the pulp quality, in particular, the breaking length and the specific tear strength, was found. The degree of beating without extreme deterioration in quality was determined by the pulp screening test. It turned out that it is preferable that the ratio of the total pulp of the mesh residue is 60 to 85%. If this proportion is less than 60%, the proportion of long fibers is reduced, resulting in a decrease in pulp quality. If it exceeds 85%, there is a high possibility that the foreign matter has not been completely cracked, which is not preferable. In the pulp sieving test of unbeaten deinked waste paper pulp, the ratio of the total pulp content of the remaining 150 mesh is usually 65 to 92%.

As described above, the coated base paper of the present invention containing the beaten-treated deinked waste paper pulp is coated with a coater by adjusting the permeation rate (absorbance) of water (aqueous solution) to a specific range. The occurrence of wrinkles and breaks in the coated paper after the coating liquid is applied to the coated base paper is reduced. When the transition length of the liquid by the Bristow method is used as an index of the water absorption of the coated base paper, the freeness is 50 to 250 ml, and the ratio of the total pulp of 150 mesh residue in the pulp screening test is 6%.
The transfer length of the coated base paper, which is 5 to 80% of the pulp in the coated base paper by the deinked waste paper pulp beaten to 0 to 85% by the Bristow method, is 10 to 50 cm, preferably 15 to 50%. When it was adjusted to 45 cm, it was found that the occurrence of wrinkles and the frequency of breakage of the coated paper after coating the coating base paper with the coating liquid by the coater were minimized. If the transition length of the liquid by the Bristow method is less than 10 cm, wrinkles and breaks frequently occur after the coating liquid is applied to the base paper for coating. On the other hand, if it is more than 50 cm,
Lack of familiarity between the coating liquid and the coating base paper causes a decrease in the adhesive strength between the coating layer and the coating base paper, and also causes a decrease in the drying property of the coated paper and uneven coating.

As a method of adjusting the water absorption of the coated base paper, that is, the transition length of the solution by the Bristow method, for example,
A method of adding various internal sizing agents such as rosin, petroleum resin, alkyl ketene dimer, alkenyl succinic anhydride and stearic anhydride to the pulp slurry to form a paper, Press, gate roll, bill blade, spray, etc., for example, various starches obtained from raw materials such as corn, potato, tapioca, wheat, etc., polyvinyl alcohol, carboxymethyl cellulose, polyacrylamide and the like, and aqueous solutions containing derivatives or denatured products thereof For example, a method of applying a conductive polymer and sizing the surface may be employed. Of course, in the method of surface sizing, various synthetic sizes such as alkyl ketene dimer system, styrene-acrylic system, α-olefin maleic anhydride system, styrene maleic anhydride system, etc. are used alone or in combination with the above water-soluble polymer. Agents, pigments, and other backside treatment agents can be used in appropriate combination. Further, by appropriately selecting the composition of the raw pulp, beating conditions, types and amounts of fillers and paper strength agents, pH conditions, drying conditions, and the like according to individual papermaking conditions, the water absorption of the coated base paper can be adjusted. Is possible.

In making the coated base paper of the present invention,
As raw pulp, in addition to deinked waste paper pulp, lignocellulosic materials such as softwood and hardwood chips, and non-wood cellulose materials from annual plants such as bagasse, kenaf, reed and straw are obtained by alkaline cooking such as kraft cooking. Pulp obtained by bleaching pulp to be used, pulp obtained by bleaching mechanical pulp, or the like is used. In the present invention, 5 to 80% by weight of the pulp component constituting the coated base paper is deinked waste paper pulp. When the ratio of the deinked waste paper pulp is less than 5% by weight (per the weight of the pulp constituting the coated base paper), the performance is as good as that of the coated base paper containing no deinked waste paper pulp. It is not necessary to apply the present invention, and if the ratio of the deinked waste paper pulp exceeds 80% by weight , the quality of the coated paper, such as the interlayer strength and whiteness , is reduced, and the product value of the coated paper is significantly reduced. The usage ratio of various bleached pulp other than the deinked waste paper pulp can be appropriately selected according to the quality required for the coated base paper.

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, acidic papermaking performed at a papermaking pH of about 4.5 or so-called neutral papermaking performed at a weakly acidic to weakly alkaline pH of about 6 to 9, containing an alkaline filler such as calcium carbonate as a main component, may be employed. Good.

The coated base paper of the present invention can be formed into paper having a rice tsubo of about ²⁰ to 400 g / m ² depending on its use and purpose.

In addition, in making the coated base paper of the present invention, if necessary, a commonly used filler for internal addition can be used. 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, white carbon, aluminosilicate One or more kinds of mineral fillers such as silica, bentonite, etc., and organic synthetic fillers (plastic pigments) such as polystyrene resin fine particles, urea formalin resin fine particles, fine hollow particles, etc. can be appropriately selected and used. The fillers contained in the broke and broke can also be used effectively.

In addition to these, various paper-making internal additives such as various anionic, cationic, nonionic or amphoteric retention improvers, drainage improvers, and paper strength enhancers which have been conventionally 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. The coating composition generally has a solid content of 40 to 75% by weight, preferably 45 to 70% by weight.
It is adjusted to the extent of the degree.

In forming a coating layer by coating a coating liquid on a base paper for coating, a coating layer may be formed by coating the coating liquid once, or divided into an undercoat layer and an overcoat layer. To form a multilayer structure. 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 solution on the base paper for coating is usually about ² to 50 g / m ² per one side in terms of dry weight, but in consideration of blank paper quality, printability and the like of the obtained coated paper. ~ 3
It is desirable to adjust it in the range of about 0 g / m ² .

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 calendar to be added. Pressure finishing is performed.

[0029]

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 method for producing the raw pulp used in Examples and Comparative Examples and the method for adjusting the transition length of the liquid in the Bristow method are described below.

Deinked waste paper pulp A : 92% waste paper from newspapers and magazines
And waste paper consisting of high-quality waste paper 8% is defibrated with a drum pulper and foreign matter is removed, and then deinked with a diffuser-type floatator.
It was then dewatered and H ₂ O ₂ was 2.1% (relative to pulp),
2.2% of OH and 0.7% of Na ₂ SiO ₃ were added thereto, bleached at 60 ° C. for 3 hours, and further deinked with a diffuser-type floatator to produce unbeaten deinked waste paper pulp A. The obtained unbeaten deinked waste paper pulp A had a hunter whiteness of 69%, a freeness of 210 ml, and a ratio of a total pulp content of 150 mesh residue in a pulp sieving test of 80%.

Deinked waste paper pulp B: 55% of newspaper and magazine waste paper
An unbeaten deinked waste paper pulp B was produced in the same manner as described above using waste paper consisting of 45% high-quality waste paper. The obtained unbeaten deinked waste paper pulp B had a hunter whiteness of 69%, a freeness of 310 ml, and a ratio of a total pulp content of 150 mesh residue in a pulp sieving test of 90%.

Raw material pulp other than deinked waste paper pulp : softwood chips (15% Douglas fir and 85% domestic pine)
In addition, unbleached pulp was produced from a hardwood chip produced in Japan using a kraft cooking liquor in a continuous digester manufactured by Kamiya Co., Ltd., and then subjected to multistage bleaching (CEHD) to obtain a Hunter whiteness of 84.5. % Softwood bleached pulp (NBKP) and hardwood bleached pulp (LBKP).

[0034]Control of liquid transition length in Bristow method
section： Below so that the coated base paper has the desired liquid transition length
The addition rate or coating amount of the sizing agent was simultaneously adjusted. What
The typical addition rate of internal sizing agent or external sizing agent
Is also shown.

Neutral sizing agent (manufactured by Oji National) 0.03% ^* Sulfuric acid band (manufactured by Oji National ) 0.5% ^* Cationized starch (manufactured by Oji National ) 0.6% ^* Size press coated starch (Oji Constarch) 1.5 g / m ² size press coated alkyl ketene dimer (manufactured by Kao Corporation) 0.02 g / m ² *% are based on absolute dry weight of papermaking raw materials.

Example 1 Bleached deinked pulp A was beaten using a double desk refiner to reduce the freeness by 60 ml to 150 ml, and the ratio of the total pulp of the remaining 150 mesh in the pulp screening test was from 80% to 8%. 72% reduction
It became.

On the other hand, NBKP was beaten using a deluxe finer to make the freeness 490 ml. Filler (light calcium carbonate / talc = 80/20) is added to pulp slurry with 75/25 deinked waste paper pulp / NBKP.
Was added to the pulp based on the absolute dry weight, and the above sizing agents were further added.
A coated base paper having an m ² and a water content of 4% was produced. The transition length of the solution in the Bristow method of this coated base paper was 12 cm.

The coating base paper thus obtained 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 / m² of rice. A coated paper having m ² and a water content of 6% was produced.

Kaolin 70 parts Heavy calcium carbonate 30 parts Starch 1.5 parts ^** Styrene butadiene latex 10.8 parts ^** Includes other dispersants, preservatives, and dyes. ** Per 100 parts of pigment. The coating liquid was used in each of the following Examples and Comparative Examples.

Example 2 The deinked waste paper pulp A was beaten using a double desk refiner to reduce the freeness from 210 ml to 60 ml to 150 ml, and the ratio of the total pulp of the remaining 150 mesh in the pulp screening test was as follows: A coated base paper was manufactured in the same manner as in Example 1 except that the coating base paper was reduced by 8% from 80% to 72%, and the transfer length of the liquid in the Bristow method of the coated base paper was adjusted to 48 cm. A coated paper was manufactured in the same manner as in Example 1 using the coated base paper.

Example 3 The deinked waste paper pulp B was beaten using a Deluxe Finer to reduce the freeness by 70 ml to 240 ml.
The ratio of the total pulp content of the 150 mesh residue in the pulp sieving test was reduced by 8% to 82%. On the other hand, NBKP and LBKP were beaten using a Deluxe Finer to reduce the freeness to 460 ml and 4 ml, respectively.
The volume was 50 ml. Deinked waste paper pulp / NBKP / LBKP
Was used in the same manner as in Example 1 using a pulp slurry having a ratio of 7/23/70. The transition length of the solution in the Bristow method of this coated base paper was 12 cm.
A coated paper was manufactured in the same manner as in Example 1 using the coated base paper thus obtained.

Example 4 The deinked waste paper pulp A was beaten using a double desk refiner to reduce the freeness by 140 ml to 70 ml, and the ratio of the total pulp of the remaining 150 mesh in the pulp screening test was 18%. 62% reduction
A coating base paper was manufactured in the same manner as in Example 1 except that the transfer length of the solution in the Bristow method of the coating base paper was adjusted to 48 cm. A coated paper was produced in the same manner.

Comparative Example 1 A coated base paper was manufactured in the same manner as in Example 1 except that the deinked waste paper pulp B was used without being beaten, and the coated base paper was used in the same manner as in Example 1 using this coated base paper. Manufactured paper.

Comparative Example 2 The deinked waste paper pulp A was beaten using a double desk refiner to reduce the freeness by 175 ml to 35 ml. In the pulp screening test, the ratio of the total pulp with the remaining 150 mesh in the pulp screening test was 25%. 55% reduction
A coated base paper was manufactured in the same manner as in Example 1 except that the above conditions were used. A coated paper was manufactured in the same manner as in Example 1 using this coated base paper.

Comparative Example 3 The transfer length of the coating base paper in the Bristow method was 6 cm.
A coated base paper was manufactured in the same manner as in Example 1 except that the above conditions were used. A coated paper was manufactured in the same manner as in Example 1 using this coated base paper.

Comparative Example 4 The transition length of the solution in the Bristow method of the coated base paper was 70c.
A coated base paper was manufactured in the same manner as in Example 1 except that m was used, and a coated paper was manufactured in the same manner as in Example 1 using this coated base paper.

Comparative Example 5 A coated base paper was produced in the same manner as in Example 1 except that a pulp slurry in which the deinked waste paper pulp / NBKP was 88/12 was used. A coated paper was produced in the same manner.

With respect to the coated papers obtained in each of the above Examples and Comparative Examples, the occurrence of wrinkles and paper breaks after application of the coating liquid by a coater, the inking property of gravure printing ink, and the surface strength were as follows. And the quality was evaluated. Table 1 shows the results. In Table 1, the deinked waste paper pulp is abbreviated as "DIP".

[0049]

Note * 1: In Comparative Example 1, unbeaten DIP was used as it is. * 2: The ratio of the total pulp of 150 mesh residue in the pulp screening test.

* 3: The occurrence of wrinkles and paper breaks in the coater
Evaluation was made based on the number of wrinkles or breaks per day. Small: Less than once / day Medium: More than once / day, less than 3 times / day Many: More than 3 times / day.

* 4: The ink inking property was visually evaluated on the following four scales for the degree of white spots on the printed matter printed by the gravure printing suitability test method (printing authority type). ◎: particularly excellent ○: excellent △: slightly poor ×: poor

* 5: The surface strength was evaluated visually on the printed matter printed using an M3 printing machine (manufactured by Miyakoshi Iron and Steel Works) and a polybutene-mixed ink. ◎: particularly excellent ○: excellent △: slightly poor ×: poor

[0054]

As can be seen from the above description, according to the present invention, the deinked waste paper pulp is beaten to a predetermined extent to break up clumps of small fibers contained therein and foreign substances that cannot be completely removed. Then, by making the coated base paper using the beaten-treated deinked waste paper pulp, it is possible to effectively reduce the minute protrusion on the surface of the coated base paper, and as a result, the coated base paper An excellent gravure printing ink inking property can be imparted to a printing coated paper manufactured using the same.

Further, by adjusting the water absorption of the coated base paper to a predetermined range, a coating liquid is applied to the base paper using a coater to produce a coated paper. It is possible to reduce the occurrence of wrinkles and breaks in the coated paper after the work, and as a result, it is possible to improve the operability of the coater.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) D21H 11/14 D21H 21/14-21/16

Claims (1)

(57) [Claims] 1. A base paper for coated paper for gravure printing, wherein the base paper comprises 5-80% by weight of a pulp component.
Consists of deinked waste paper pulp whose freeness (CSF) is adjusted to 50-250 ml by beating.
Further, the transfer length of the base paper by the Bristow method was set to 10
Gras, characterized in that is obtained by adjusting the ~50cm
Base paper for coated paper for via printing.