JP3058021B2 - Method for producing bulky matte coated paper - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a matt coated paper, and particularly to a method for producing a matte coated paper, which is strong, has excellent printability, and eliminates blanket piling and improper fixing of printing ink (printing off of printing ink). The present invention relates to a method for producing a bulky matte coated paper.

[0002]

2. Description of the Related Art In recent years, coated paper is widely used in various fields as various printing papers and industrial papers. Such a coated paper is finished as a coated paper having various characteristics, depending on the composition of the coating material to be coated (the type of pigment or adhesive), the coating method, or the finishing method.

For example, coated paper finished by a cast method has high gloss and high smoothness, and is used for printed matter, fashion bags, and the like that require a sense of quality. Further, versatile glossy coated paper is also widely used for various printed matter, industrial paper, and the like. On the other hand, there is a so-called matte coated paper which is hardly required to have a gloss on the surface of the coated paper. Since such matte coated paper intentionally suppresses its surface gloss, it has the power to appeal a visually elegant image as compared to a normal coated paper having a blank gloss, and furthermore, it becomes fatigued when printed. The range of use has been widely extended to high-quality art printing, catalogs, brochures, calendars, commercial publication text sheets, and the like because they can be viewed without feeling.

[0004] By the way, matte coated paper generally has a surface gloss of 40% or less with a gloss value of 75 ° as measured by a gloss meter in accordance with JIS P-8142. ing. In general, there are two types of matte coated paper, one of which is called mat-gloss type,
This is a dull matte coated paper that has a low blank gloss but a high ink (print) gloss, and the other is called a mat-mat type, and has a low mat gloss both in blank gloss and ink gloss. It is erased coated paper.

That is, in the former method of producing a dull matte coated paper, it is necessary to suppress the surface gloss of white paper and to develop an ink gloss. Therefore, it is important to provide a dense coated layer surface. It is. For this purpose, a coating composition using a relatively fine pigment having a needle-like or plate-like shape such as satin white, kaolin, and aluminum hydroxide and having an average particle diameter of about 0.5 to 1.5 μm is used as a base paper. Coating and finishing,
For example, it is a matte coated paper of low white paper gloss and high ink gloss in which the surface of a coated layer as proposed in JP-A-4-108199 is matted by a calender having a roughened metal roll. . Therefore, white paper gloss (JIS P
-8142 method) also shows a relatively high gloss value at about 25 to 40%.

[0006] The latter method for producing matte matte coated paper mainly uses a relatively coarse pigment of about 2 to 10 µm among the pigments for coated paper used in the production method of ordinary printed coated paper. The base material is coated with an aqueous coating composition as a component, dried and then finished as it is, or finished by applying a very light calendering treatment.
This is a matte coated paper having a low degree of so-called low white paper gloss and low ink gloss.

[0007] In the latter case, in particular, as compared with a coated paper exhibiting a normal gloss or a dull matte coated paper of the former, coarse heavy calcium carbonate is used as a main component of a pigment and calendering treatment is performed. Is very light, so the smoothness is limited and the printability is poor. Furthermore, when such matte matte coated paper is subjected to a printing process,
When the plain-printed paper is stacked in a stack after printing, the printing ink is transferred to a blank portion, so-called ink set-off tends to occur, and the quality of the printed matter tends to be significantly reduced.

After printing is completed, bookbinding is performed through a bookbinding process. In that case, the printed part and the blank part will come into contact with the folding machine or collating machine, the printing ink will transfer to the blank part, or the front cover and back cover will come into contact after stacking after binding. In fact, there is a problem that the printing ink is transferred to a blank paper surface, and the quality of printed matter is deteriorated.

[0009]

DISCLOSURE OF THE INVENTION The present invention provides good printability and print workability because both the gloss of blank paper and the gloss of printing ink are suppressed to a low level, no ink set-off or blanket pile occurs in the printing process. Have and bulky,
An object of the present invention is to provide a method for obtaining a matte matte coated paper having a firm paper.

[0010]

According to the present invention, an aqueous coating composition comprising a pigment and an adhesive as a main component is coated on a base paper.
In the method for producing a bulky matte coated paper which is calendered after drying, as the base paper, the tension is 0.7 g / cm.
Less than ³ , and Beck smoothness is 7 seconds / 10 cc to 20 seconds /
Using a base paper of 10 cc, as a pigment in the water-based coating composition, 5 to 25% by weight of satin white based on all pigments,
And 50 to 95% by weight of heavy calcium carbonate having an average particle diameter of 5 to 15 μm, and further, calendering is performed so that the finished product has a tension of 1.10 g / cm ³ or less. This is a method for producing a bulky matte coated paper.

[0011]

According to the present inventors, as described above, both the glossiness of blank paper and the glossiness of printing ink are suppressed to a low level, and there is no blanket piling or set-off phenomenon of printing ink in the printing process, and the printability is excellent. In order to obtain a matte matt coated paper with a bulky and stiff paper, we studied and studied intensively.

As a result, an aqueous coating composition mainly comprising satin white, heavy calcium carbonate having a specific particle size and an adhesive is coated on a base paper having a specific strength and smoothness, and dried. The matte coated paper made by this method has both low glossiness and print gloss, strong paper stiffness, excellent printability, eliminating blanket piling and poor ink fixation, and extremely excellent bulky matte coated paper. Was obtained, and finally the present invention was completed.

First, the base paper which is a feature of the present invention will be described. The tension of the base paper usually used for coated paper is not particularly limited, but is generally 0.7 to 0.95 g / c.
m ³ is used. In the present invention,
The desired effect can be obtained by using a base paper having a tension of less than 0.7 g / cm ³ and a Beck smoothness of 7 seconds / 10 cc to 20 seconds / 10 cc. By the way, if a base paper having a tension of 0.7 g / cm ³ or more is used, the bulkiness and paper stiffness are undesirably low when finished into a final product. When a base paper having a Beck smoothness of less than 7 seconds / 10 cc is used, the smoothness after providing the coating layer is poor,
Blanket piling occurs when finished into a product, and printability deteriorates. On the other hand, when a base paper exceeding 20 seconds / 10 cc is used, the ink gloss after the coating layer is provided tends to be developed, and the matte print finish becomes difficult in terms of printability and a desired matte effect cannot be obtained. . Therefore, the effect desired by the present invention is exhibited only when the conditions of both the tension and the smoothness specified above are satisfied as the base paper.

Incidentally, a method (means) for reducing the tension of the base paper
Examples include loosening the pulp, using bulky fillers, reducing initial dewatering in the paper machine press, reducing paper machine calender pressure, or selecting pulp fibers (eg, pulp with thick cell membranes). ) Can be used to adjust the tension of the base paper. The method for adjusting the Beck smoothness of the base paper can be adjusted by beating the pulp, adjusting the type and amount of filler internally added to the base paper, adjusting the calender pressure of the paper machine, and the like. Since the tension and smoothness of the base paper can be adjusted by the same method and by several kinds of requirements, it is easy to balance and one or two or more of the above means are taken into consideration in consideration of the quality specification of the final product. By appropriately combining them, the desired base paper conditions can be adjusted.

Next, an aqueous coating composition which is the second feature of the present invention will be described. Conventionally, as a method of obtaining a coated paper having high smoothness and high gloss and having excellent printability, there is a method of obtaining a coated paper by applying an aqueous coating composition containing satin white to a base paper. Are known. However, satin white is generally used for glossy coated paper because it exhibits high gloss based on a unique particle shape, particle size, and orientation. There is also an example in which satin white is used for matte coated paper, but this is also a matte-gloss type dull matte coated paper, and the manufacturing method is also performed by treatment with a roughening roll, etc. It is to suppress.

The present inventors have paid attention to characteristics such as the unique particle shape, particle diameter, and orientation of satin white, and further combined with calcium carbonate having a specific particle diameter to obtain white paper gloss and print gloss. , And high quality matte matte coated paper can be obtained.

That is, when various experiments were repeated focusing on the forming ability of a bulky coating layer and the high oil absorption performance of Sachin White as its characteristics, it was found that an extremely excellent effect was exhibited. However, on the other hand, satin white as described above has a disadvantage that the gloss is too high based on the unique particle shape, particle diameter, orientation tendency, etc., and it is understood that it is difficult to apply it as it is, and further studies are repeated. Was. As a result, it can be seen that matte matte coated paper can be obtained by combining with heavy calcium carbonate having a specific particle size that can suppress gloss, and gloss control can be sufficiently performed. The inventors have succeeded in obtaining an extremely excellent matte matte coated paper desired by the present invention.

Next, heavy calcium carbonate having a specific particle size, which is an important pigment in the present invention, will be described. It is important to use heavy calcium carbonate having an average particle diameter of 5 to 15 μm as measured by a Sedigraph 5000-1 (manufactured by Shimadzu Corporation) in the present invention. If the thickness is less than 5 μm, it is difficult to obtain low gloss. On the other hand, if it exceeds 15 μm, the microscopic smoothness of the coating layer is impaired, the printability is deteriorated, and furthermore, blanket piling and scratches on the surface of the coating layer are liable to occur, which is not preferable. It is important that the amount of heavy calcium carbonate is 50% by weight or more based on all pigments. By the way, 50% by weight
If it is less than 1, glossiness of white paper and ink gloss are easily developed, and it is difficult to obtain a product having a desired matte tone and excellent printability.

As described above, as a pigment for a coating layer on a specific base paper, a specific amount of satin white, which tends to produce gloss, and calcium carbonate having a specific average particle diameter, which is relatively low in gloss, are blended. By the balance effect,
For the first time, it is possible to obtain a mat-matte matte coated paper which is bulky and has excellent printability. In addition, as the pigment for the coating layer, in addition to the above-mentioned satin white and heavy calcium carbonate, the object of the present invention, for example, precipitated calcium carbonate, talc, aluminum hydroxide, titanium dioxide, titanium dioxide, in a range not impairing the effect, One or more of inorganic pigments used as general pigments for coated paper such as barium sulfate and zinc oxide, and organic pigments such as plastic pigments, synthetic resin hollow pigments and binder pigments can be suitably used. In particular, when the precipitated calcium carbonate having an average particle size in the range of 0.5 to 4 μm is blended in an amount of 10% by weight or more with respect to all the pigments, the coating layer tends to be bulky, and the effect of eliminating blanket piling is excellent. It has been found that high quality matte coated paper can be obtained.

The adhesive used in the aqueous coating composition is not particularly limited, and may be any of the adhesives used in ordinary coated paper manufacturing fields, such as various starches, casein, and soy protein. Proteins such as styrene-butadiene copolymer latex, synthetic polymers such as acrylic latex and polyvinyl alcohol can be suitably used, among which styrene-butadiene copolymer latex and acrylic latex are particularly preferred. .

Further, in addition to the above, various auxiliaries such as a dispersant, a preservative, a dye, a water retention agent, a curing agent and a water resistance agent can be added as required.

In the present invention, the desired matte coated paper is obtained by coating the aqueous coating composition (coating liquid) obtained as described above on the previously specified base paper. It is. The coating amount of the coating liquid in this case is 10 to 25 g in solid content per one side in consideration of the quality of the finished product.
/ M ² is preferably adjusted. Furthermore, the composition ratio between the coating layer and the base paper layer of the product obtained by the method of the present invention is as follows: coating layer / (coating layer + base paper layer) = 20 to 3
It was found that the composition having the ratio of 5% by weight was the most preferable range in terms of quality balance such as paper strength and printability.

The method of coating the coating liquid on the base paper is suitably performed by using a coating apparatus used in the field of ordinary coated paper, for example, an air knife coater, various blade coaters, a champlex coater and the like. Although it is not particularly limited, a coating method using a blade coater is most suitable in the present invention that requires smoothness of the coating layer.

The coated paper obtained by the above method is
The paper is passed through various known and publicly-applied finishing presses, for example, a super calender, a gloss calender, etc., to finish the product. In the case of the present invention, for the purpose, it is necessary to adopt a pressing method that facilitates smoothing and hardly develops gloss, and a method of finishing by passing the paper through a calender equipped with a hard resin roll or the like is desirable. It is particularly important that the pressing operation is performed so that the value of the final product does not exceed 1.10 g / cm ³ . By the way, 1.1
If it exceeds 0 g / cm ³ , the paper stiffness is remarkably reduced, and a desired bulky matte coated paper cannot be obtained.

[0025]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but it is needless to say that the present invention is not limited thereto.
Unless otherwise specified, parts and% in the examples indicate "parts by weight" and "% by weight" in terms of solid content, respectively.

Examples 1, 4 and 6, Comparative Examples 5 and 6 As pigments, 10 parts of satin white, 65 parts of heavy calcium carbonate having an average particle diameter as shown in Table 2 and 25 parts of precipitated calcium carbonate were used. (Total 100 parts), and an aqueous coating composition (coating liquid) having a concentration of 60% and comprising 5 parts of oxidized starch as an adhesive and 10 parts of a styrene-butadiene copolymer latex was prepared. The thus obtained coating liquid is applied to a high quality base paper having a tension of 0.65 g / cm ³ (medium tsubo 130 g / m ² )
The coated paper was coated on both sides with a blade coater so that the dry weight was 15 g / m ^{2 on} one side, and then dried to obtain a coated paper. Next, the coated paper was super-calendered so that the finishing tension was 0.95 g / cm ³ , to obtain a matte coated paper.

The bulky matte-coated paper thus obtained was evaluated for quality by the following evaluation method.
The results are summarized in Table 3.

Example 2, Comparative Examples 1-2 Tensions as shown in Table 1 (Comparative Example 1: 0.60 g / c
m^Three, Example 2: 0.68 g / cm^ThreeComparative Example 2: 0.
80g / cm^Three) Except for using high quality base paper with
A coated paper was obtained in the same manner as in Example 1. In addition, this coated paper
The finishing tension was as shown in Table 3 (Comparative Example 1: 0.9
0 g / cm^Three, Example 2: 0.98 g / cm ^Three, Comparative example
2: 1.05 g / cm^Three) To be a super carry
To obtain a bulky matte coated paper. Thus obtained
The quality of the coated paper was evaluated in the same manner as in Example 1.
The results were summarized in Table 3.

Comparative Example 3 65 parts of heavy calcium carbonate and 35 parts of precipitated calcium carbonate having an average particle size as shown in Table 2 were used as pigments.
A bulky matte coated paper in the same manner as in Example 1 except that a coating solution having a concentration of 65% consisting of 5 parts of oxidized starch and 10 parts of a styrene-butadiene copolymer latex per 100 parts of a pigment was used as an adhesive. I got The quality of the coated paper thus obtained was evaluated in the same manner as in Example 1, and the results are shown in Table 3.

Example 3 15 parts of satin white as a pigment, 65 parts of heavy calcium carbonate and 20 parts of precipitated calcium carbonate having an average particle size as shown in Table 2, 5 parts of starch oxide as an adhesive, styrene-butadiene A bulky matte coated paper was obtained in the same manner as in Example 1 except that a coating liquid of 10 parts of a copolymer latex having a concentration of 55% was used. The quality of the coated paper thus obtained was evaluated in the same manner as in Example 1, and the results are shown in Table 3.

Comparative Example 4 As a pigment, 30 parts of satin white, 65 parts of heavy calcium carbonate having an average particle diameter as shown in Table 2 and 5 parts of precipitated calcium carbonate, 5 parts of starch oxide as an adhesive, and styrene-butadiene were used. A bulky matte coated paper was obtained in the same manner as in Example 1 except that a coating liquid having a concentration of 50% consisting of 10 parts of a copolymer latex was used. The quality of the coated paper thus obtained was evaluated in the same manner as in Example 1, and the results are shown in Table 3.

Examples 7 to 9 Base paper having a tension of 0.65 g / cm ³ and a base paper as shown in Table 1 (Example 7: 144 g / m ² , Example 8: 140 g / cm ²⁾
m ² , Example 9: 100 g / m ² ), and the coating amount per one side (Example 7: 8 g / m ² )
² , Example 8: 10 g / m ² , Example 9: 30 g / m ²
m ² ), and a bulky matte coated paper was obtained in the same manner as in Example 1. The quality of the coated paper thus obtained was evaluated in the same manner as in Example 1, and the obtained results were shown in Table 3.
Are shown together.

Examples 10 to 11 and Comparative Example 7 In Example 1, the conditions of the final finished super calender were changed, and the product tension was changed in Example 1.
0 (0.90 g / cm ³ ), Example 11 (1.00 g / cm ³ )
cm ³ ) and Comparative Example 7 (1.15 g / cm ³ ), to obtain a bulky matte coated paper in the same manner as in Example 1. The quality of the coated paper thus obtained was evaluated in the same manner as in Example 1, and the results are shown in Table 3.

The quality of the matte coated paper was evaluated based on the following method. Table 3 summarizes the obtained results.

[Evaluation Items and Evaluation Methods]

(Tension of base paper) A rice tsubo was measured in accordance with JIS-P-8124, then a paper thickness was measured in accordance with JIS-P-8118, and the rice tsubo was divided by the paper thickness. (Degree: g / cm ³ ).

(Base paper smoothness) Measured using a Beck smoothness meter according to JIS-P-8119 method (unit: second / second).
10cc).

(Average Particle Diameter of Pigment) The particle size distribution was measured by a gravity sedimentation method (measurement device / SEDI-GRAPH 5000-1 / manufactured by Shimadzu Corporation), and the value when the accumulated weight was 50% was taken as the average particle diameter.

(Blank glossiness) The glossiness was measured at 75 degrees according to JIS-P-8142.

(White Paper Smoothness) Measured using a smoother smoothness meter (manufactured by Toei Electronics Co., Ltd.). The smaller the value, the higher the smoothness.

(Paper waist / stiffness) TAPPI No. 40
In accordance with the law, measure the sample in the vertical and horizontal eyes,
The obtained results were averaged to determine the rigidity. (Unit: mg
f)

(Printing Ink Gloss) Using a diamond offset printing machine (manufactured by Mitsubishi Heavy Industries, Ltd.), four-color printing was performed at a printing speed of 8,000 sheets / hour. The ink gloss of the four-color overlapping portion was visually determined. ◎: The ink sinks, there is no ink gloss, and the print finish is very soft and matte. ：: The ink settled moderately, there was no ink gloss, and the print was matte. X: Ink gloss is developed, and a mat-like print cannot be obtained.

(Offset of printing ink) Using a diamond offset printing machine (manufactured by Mitsubishi Heavy Industries), four-color printing (four colors of black, indigo, indigo, red, and yellow) was performed at a printing speed of 8,000 sheets / hour. After printing, about 2,000 printed materials were stacked on the printing surface, and allowed to stand at room temperature for about 24 hours.
Then, turn over the printed materials one by one,
The stained state (set-off) by the printing ink on the back side (blank paper part) of the printed portion in which the color was overprinted and the other printed matter in contact with the portion was visually determined. A: Ink fixation is fast, and no ink transfer (stain) to the white paper portion is observed. : Good fixation of ink, almost no ink transfer (stain) to white paper Δ: Poor fixing of ink, transfer of ink (stain) to white paper part is observed. ×: Very poor fixation of the ink, and considerable ink transfer (dirt) to the white paper part is observed.

(Blanket Piling for Printing) Using a diamond offset printing machine (manufactured by Mitsubishi Heavy Industries), 8000
3000 single-color printing was performed at a printing speed of sheets / hour, and after the printing was completed, the blanket and the printed matter were visually judged. ◎: No accumulation of the coating composition (coating layer) was observed on the blanket at the end of printing. : Although the coating layer was removed little by little on the blanket, it was enough to be covered by the automatic cleaning device, and the print and printed matter were not affected. Δ: The coating layer was taken on the blanket, but the effect on the printed matter was hardly recognized. X: The coating layer was taken on the blanket, and the printing surface was affected during the printing, and beautiful printing was not possible.

[0045]

[Table 1]

[0046]

[Table 2]

[0047]

[Table 3]

[0048]

As is clear from Table 3, the matte coated papers obtained in the examples of the present invention have low white paper gloss and low print gloss, particularly strong paper stiffness (rigidity), and blanket. It was a bulky matte coated paper excellent in printability with very little piling or ink set-off.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) D21H 19/00-27/42

Claims (3)

(57) [Claims] In a method for producing a bulky matte coated paper which is coated with an aqueous coating composition mainly containing a pigment and an adhesive on a base paper, dried and calendered, the base paper is used as a base paper. Using base paper having a degree of less than 0.7 g / cm ³ and a Beck smoothness of 7 seconds / 10 cc to 20 seconds / 10 cc,
As a pigment in the aqueous coating composition, satin white is 5 to 25% by weight based on all pigments, and an average particle diameter is 5 to 15%.
μm of heavy calcium carbonate in an amount of 50 to 95% by weight, and the finished product has a strength of 1.10 g /
A method for producing bulky matte-coated paper, characterized in that the paper is calendered so as to have a size of not more than cm ³ . 2. The pigment has an average particle size of 0.5 to 4 μm.
The method for producing a bulky matte-coated paper according to claim 1, wherein the precipitated calcium carbonate is contained in an amount of 10% by weight or more based on all pigments. 3. The coating composition according to claim 1, wherein the coating amount of the aqueous coating composition after drying is 10 to 25 g / m ² per side.
A method for producing the bulky matte-coated paper described above.