JP2004162198A - Gloss lightweight coated paper for rotary offset printing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain gloss lightweight coated paper for rotary offset printing which is produced in an excellent coated state in high-speed blade coating suitability while controlling occurrence of especially streak and has sufficient gloss while keeping excellent blister resistance. <P>SOLUTION: The gloss lightweight coated paper for rotary offset printing is obtained by coating one side of base paper (no size press base paper) not to be coated using a coating liquid with starch and pigment by a size press, a gate roll coater, etc., with 8-15g/m<SP>2</SP>of a pigment coating liquid mixed with ≥60mass% of wet ground calcium carbonate having ≤1.2μm average particle diameter and ≥30mass% of fine-grain kaolin having ≤0.8μm average particle diameter as pigment and ≥8mass% based on 100mass% of the pigment of a styrene-butadiene latex having ≥80% gel content as a binder using a blade coater. <P>COPYRIGHT: (C)2004,JPO

Description

【００４６】
【表２】

【００４７】
評価；
上記表２の結果より、実施例１および比較例１を比較すると、実施例１の場合はストリークが許容範囲内であるのに対して、重カル部数を減らした配合の比較例１ではストリークが多発してしまい、製品として好ましくない。実施例２および比較例２を比較すると、実施例２の場合は白紙光沢、印刷光沢が許容範囲内にあるのに対して、重カルの平均粒子径を大きくした配合である比較例２では白紙光沢、印刷光沢が低く、製品として好ましくない。実施例３および比較例３を比較すると、実施例３の場合は白紙光沢が許容内にあるのに対して、カオリンの平均粒子径を大きくした配合である比較例３では白紙光沢が低く、製品として好ましくない。実施例４および比較例４を比較すると、実施例４の場合は印刷光沢が許容内にあるのに対して、ラテックスのゲル含有量を減らした配合である比較例４では印刷光沢が低く、製品として好ましくない。実施例１および比較例５を比較すると、実施例１の場合は耐ブリスター性が許容内にあるのに対して、澱粉サイズの原紙を用いた比較例５では耐ブリスター性が悪く、製品として好ましくない。以上、実施例１〜４ではストリーク、ブリスター、白紙光沢、印刷光沢のいずれも許容範囲内にあり、良好な結果であることがわかる。
【００４８】
【発明の効果】
本発明のノーサイズプレス原紙を用いたオフ輪用グロス軽量コート紙は、高速ブレード塗工適性、特にストリークの発生を抑制して良好な塗工状態により製造することを可能とし、且つ優れた耐ブリスター性を維持しつつ、十分な光沢を備えたオフ輪用グロス軽量コート紙が得られる。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a light weight coated gloss paper for off-wheels, and more particularly, to high-speed blade coating aptitude, in particular, it enables production under a good coating state by suppressing the occurrence of streaks, and has excellent resistance. The present invention relates to an off-wheel glossy lightweight coated paper having sufficient gloss while maintaining blister properties.
[0002]
[Prior art]
Generally, when coating is performed using a pigment coating liquid with a blade coater on a base paper (no size press base paper) that is not subjected to a coating process using a coating liquid with starch or a pigment using a size press, a gate roll coater, or the like, Frequent streaks result in defective quality products.
[0003]
When the base paper is subjected to a coating process using a coating solution of starch or a pigment by a size press, a gate roll coater, or the like, streaks can be avoided when the coating of the pigment coating solution is performed by a blade coater.
[0004]
However, since the base paper surface is hardened by undercoating the base paper with starch and a starch coating layer is formed, when the paper surface is dried by web offset printing, the escape path of the water vapor in the base paper layer is blocked, and blisters are generated. There is a disadvantage that it becomes easier.
[0005]
In addition, since the frequency of blisters increases as the gel content of the latex increases, latex having a gel content of 50% or less is used in ordinary light-weight gloss coated paper for off-wheels. Reference 1).
[0006]
However, a latex having a low gel content has lower print gloss than a latex having a high gel content, and is not preferable in print quality.
[0007]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 08-049187
[Problems to be solved by the invention]
An object of the present invention is to provide high-speed blade coating aptitude, in particular, to enable production under a good coating state by suppressing the occurrence of streaks, and to have sufficient gloss while maintaining excellent blister resistance. It is intended to provide a gross lightweight coated paper for an off-wheel.
[0009]
[Means for Solving the Problems]
The present inventor has conducted intensive studies in view of the above, and as a result, has come to invent the gross lightweight coated paper for an off-wheel of the present invention.
[0010]
That is, the gross lightweight coated paper for off-wheels of the present invention is used as a pigment on a base paper (no-size press base paper) which is not subjected to a coating treatment using a coating liquid of starch or a pigment by a size press, a gate roll coater or the like. 60% by mass or more of wet heavy calcium carbonate having a particle size of 1.2 μm or less and 30% by mass or more of fine kaolin having an average particle size of 0.8 μm or less, and a styrene / butadiene latex having a gel content of 80% or more as a binder. It is characterized in that a pigment coating liquid containing 8% by mass or more per 100% by mass of a pigment is coated with 8 to 15 g / m ² on one side using a blade coater.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the gross lightweight coated paper for offset wheels of the present invention will be described in detail.
[0012]
Generally, streak is a phenomenon peculiar to the blade coater, and foreign matter such as pulp fiber and felt fiber of the base paper and agglomerates of the coating liquid are caught between the blade tip and the base paper. (Streaks) occur.
[0013]
Normally, a base paper is coated with a starch or pigment coating liquid using a size press, gate roll coater, etc. to provide a starch coating layer and prevent peeling of pulp fibers and felt fibers directly under the blade. Streak generation is suppressed.
[0014]
The present invention relates to the flow of a coating liquid directly below a blade by blending 60% by mass or more of wet heavy calcium carbonate having a lower viscosity than kaolin at a high shear rate into a pigment coating liquid using a no-size press base paper. In addition, foreign matter is prevented from being caught between the blade tip and the base paper. Also, even if it is interposed, it is easy to come off.
[0015]
When the wet heavy calcium carbonate content is less than 60% by mass, when high-speed blade coating is performed on a no-size press base paper, a foreign substance caught between the blade and the paper surface is hard to be removed, and a streak occurs.
[0016]
Paper coated with a pigment coating liquid containing a high amount of wet heavy calcium carbonate generally has a reduced white paper gloss. Therefore, by using wet heavy calcium carbonate pulverized to an average particle size of 1.2 μm or less, and further mixing 30% by mass or more of fine kaolin having an average particle size of 0.8 μm or less, sufficient white paper gloss can be obtained at present. Have secured.
[0017]
When the content of the fine kaolin is less than 30% by mass, the glossiness of the white paper is low as a gloss coated light weight paper for an off-wheel, resulting in a defective product. The same can be said for kaolin having an average particle diameter of 0.8 μm or more.
[0018]
By using the above-mentioned wet heavy calcium carbonate and the fine-grained kaolin in combination, the viscosity of the pigment coating liquid at a high shear rate is further reduced, the flowability of the coating liquid is further improved, and the generation of streaks is suppressed. I do. The coated paper thus obtained also has a sufficient white paper gloss.
[0019]
In the present invention, by using the no-size press base paper, since there is no starch coating layer on the base paper surface, there is an escape path for water vapor in the base paper layer, and blisters are hardly generated.
[0020]
By using the above-mentioned no-size press base paper, excellent blister resistance is maintained even when a latex having a gel content of 80% or more, in which blisters are frequently generated, is blended. Further, by using a latex having a high gel content, it is possible to obtain a coated gross lightweight coated paper having improved printing gloss and excellent printability.
[0021]
Further, by forming the base paper by a no-size press, there is no need for drying with an after-dryer as compared with the case of using a size press, so that there is an advantage that energy cost can be reduced and the cause of paper breakage can be reduced.
[0022]
The base paper used in the present invention includes pulp such as chemical pulp such as LBKP and NBKP, mechanical pulp such as GP, PGW, RMP, TMP, CTMP, CMP and CGP, and pulp such as waste paper pulp such as DIP. Includes various fillers such as calcium carbonate, talc, clay, kaolin, etc., sizing agents, fixing agents, retention agents, cationizing agents, paper strength agents, etc. .
[0023]
As the paper machine to be used, various types of paper machines such as a fourdrinier system, a circular net system, a twin-wire system, a hybrid system, a gap former type, and a roll former type can be used.
[0024]
Further, as the pigment of the coating liquid used in the present invention, a commonly used pigment can be used. Examples of the pigment include kaolin, calcium carbonate, clay, satin white, talc, titanium oxide, aluminum hydroxide, silica, zinc oxide, activated clay, acid clay, silicon clay, and plastic pigment.
[0025]
The method of coating is mainly applied to a high-speed blade coater, but the type of the blade coater is not particularly limited, and various blade coaters such as a short dowel coater, a roll applicator type, and a nozzle applicator type can be used. Yes, bevel coating and vent coating are also possible.
[0026]
The coated paper of the present invention can be subjected to a calendar treatment such as a super calendar, a soft calendar, and a machine calendar.
[0027]
【Example】
Hereinafter, the effects of the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto. In addition,% and part in an Example show the mass% and the mass part, respectively.
[0028]
Example 1
The pulp and internal chemicals described below were adjusted, and paper was formed by a no-size press using a twin-wire paper machine to obtain a base paper for coating having a basis weight of 45 g / m ² .
<Base paper>
LBKP 70 parts NBKP 30 parts Calcium carbonate 6 parts Commercial cationic starch 2 parts Commercial cationic polyacrylamide retention aid 0.02 parts
Following to adjust the solid content concentration of 64% of the coating solution in accordance with the amount, and double-sided coating one surface at a time 10 g / m ² at a speed of 1500 m / min Drying by means of a blade coater coating base paper for the above.
[0030]
<Pigment coating liquid>
60 parts of wet heavy calcium carbonate having an average particle diameter of 1.2 μm 30 parts of kaolin having an average particle diameter of 0.8 μm 10 parts of kaolin having an average particle diameter of 1.1 μm 8 parts of a copolymer latex having a gel content of 80% 8 parts of commercially available polyacrylic dispersion 0.1 part commercial starch 2 parts commercial calcium stearate 0.5 part sodium hydroxide adjusted to pH 9.7
The above-mentioned coated paper was subjected to a super calender treatment under the conditions of a linear pressure of 300 kg / cm and a speed of 700 m / min to obtain a gross lightweight coated paper for an off-wheel. The obtained light-weight gloss coated paper for off-wheel was subjected to humidity control for at least 24 hours in a constant temperature and humidity room at 23 ° C. and 50% RH, and then the paper quality was measured.
[0032]
Example 2
In the same manner as in Example 1, except that 40 parts of kaolin having an average particle diameter of 0.8 μm and 0 parts of kaolin having an average particle diameter of 1.1 μm were used in the formulation of the pigment coating liquid according to Example 1, Lightweight coated paper was manufactured.
[0033]
Example 3
In the same manner as in Example 1 except that 70 parts of wet heavy calcium carbonate having an average particle diameter of 1.2 μm and 0 parts of kaolin having an average particle diameter of 1.1 μm were used in the formulation of the pigment coating liquid according to Example 1. Gloss lightweight coated paper for off-wheel was manufactured.
[0034]
Example 4
A gross lightweight coated paper for an off-wheel was manufactured in the same manner as in Example 1 except that the gel content of the copolymer latex was changed to 90% and the number of parts was changed to 10 parts in the formulation of the pigment coating liquid according to Example 1. .
[0035]
Comparative Example 1
In the formulation of the pigment coating liquid according to Example 1, 40 parts of wet heavy calcium carbonate having an average particle diameter of 1.2 μm, 40 parts of kaolin having an average particle diameter of 0.8 μm, and kaolin having an average particle diameter of 1.1 μm were used. A gross lightweight coated paper for off-wheel was manufactured in the same manner as in Example 1 except that the amount was changed to 20 parts.
[0036]
Comparative Example 2
In the formulation of the pigment coating liquid according to Example 1, the average particle size of the wet heavy calcium carbonate was changed to 1.5 μm, and 40 parts of kaolin having an average particle size of 0.8 μm and kaolin having an average particle size of 1.1 μm were used. A gross lightweight coated paper for an off-wheel was manufactured in the same manner as in Example 1 except that the amount was changed to 0 part.
[0037]
Comparative Example 3
In the formulation of the pigment coating liquid according to Example 1, 70 parts of wet heavy calcium carbonate having an average particle diameter of 1.2 μm, 0 parts of kaolin having an average particle diameter of 0.8 μm, and 30 parts of kaolin having an average particle diameter of 1.1 μm were used. In the same manner as in Example 1 except that the above-mentioned parts were used, a light-weight gloss coated paper for an off-wheel was manufactured.
[0038]
Comparative Example 4
A gross lightweight coated paper for an off-wheel was manufactured in the same manner as in Example 1 except that the gel content of the copolymer latex was changed to 50% and the number of parts was changed to 10 parts in the formulation of the pigment coating liquid according to Example 1. .
[0039]
Comparative Example 5
A gross lightweight coated paper for an off-wheel was manufactured in the same manner as in Example 1 except that a base paper for coating formed by performing a starch size press was used.
[0040]
Table 1 shows the compounding amount, the gel amount of the latex, and the presence or absence of the size press according to Examples 1 to 4 and Comparative Examples 1 to 5 described above. In addition, the obtained gloss coated paper for off-wheel gloss was evaluated by the following evaluation method, and the results are shown in Table 2.
[0041]
1) The paper surface being coated with a streak blade coater was visually evaluated by transmission and evaluated in three stages (（, Δ, ×). △ and △ are within the allowable range.
[0042]
2) Blister resistance The printed matter was visually evaluated in three stages (○, Δ, ×). △ and △ are within the allowable range.
[0043]
3) Gloss of white paper According to JIS P8142, it was measured using a Murakami digital gloss meter (model GM-3D) (incident angle, reflection angle: 75 degrees). The blank gloss value of 55% or more is within the allowable range.
[0044]
4) Print Gloss The print gloss of the four-color solid printed portion of the printed matter was measured using a Murakami digital gloss meter (model GM-3D) according to JIS P8142 (incident angle, reflection angle 60 degrees). The print gloss value of 50% or more is within the allowable range.
[0045]
[Table 1]

[0046]
[Table 2]

[0047]
Evaluation;
From the results in Table 2 above, comparing Example 1 and Comparative Example 1, the streak was within the allowable range in Example 1, whereas the streak was reduced in Comparative Example 1 in which the number of heavy curls was reduced. It occurs frequently and is not preferable as a product. A comparison between Example 2 and Comparative Example 2 shows that, in Example 2, white paper gloss and print gloss were within the allowable range, whereas in Comparative Example 2 in which the average particle diameter of heavy particles was increased, white paper was used. The gloss and print gloss are low, which is not desirable as a product. Comparing Example 3 and Comparative Example 3, the white paper gloss was acceptable in the case of Example 3, whereas the white paper gloss was low in Comparative Example 3 in which the average particle size of kaolin was increased, and the product was low. Is not preferred. Comparing Example 4 with Comparative Example 4, the print gloss was acceptable in Example 4, whereas the print gloss was low in Comparative Example 4 in which the gel content of the latex was reduced. Is not preferred. Comparing Example 1 and Comparative Example 5, the blister resistance was acceptable in Example 1, whereas the blister resistance was poor in Comparative Example 5 using starch-size base paper, which was preferable as a product. Absent. As described above, in Examples 1 to 4, all of the streaks, blisters, glossiness of blank paper, and print gloss were within the allowable ranges, and it was found that the results were good.
[0048]
【The invention's effect】
The gross lightweight coated paper for off-wheels using the no-size press base paper of the present invention enables high-speed blade coating aptitude, in particular streaking can be suppressed, and can be manufactured in a good coating state. Gloss lightweight coated paper for off-wheel wheels having sufficient gloss can be obtained while maintaining blister properties.

Claims (1)

A wet heavy calcium carbonate having an average particle diameter of 1.2 μm or less as a pigment is coated on base paper (no-size press base paper) which is not subjected to a coating process using a coating solution of starch or a pigment by a size press, a gate roll coater, or the like. Pigment coating in which 30% by mass or more of fine kaolin having an average particle size of 0.8 μm or less and at least 8% by mass of a styrene / butadiene latex having a gel content of 80% or more are blended as a binder per 100% by mass of the pigment. gloss lightweight coated paper for web offset, characterized by comprising ^two coating one surface 8~15g / m using a blade coater liquid.