JPH05279984A - One-side mat-coated paper - Google Patents

Abstract

PURPOSE:To provide a coated paper having mat surface on one side and glossy surface on the other side. CONSTITUTION:A surface of a coated paper is pressed twice with a roughened roll 1 of a supercalender A (having a surface roughness Rmax of 8-35mum defined by JIS B0601), the reverse surface of the paper is pressed five times with chilled rolls 3 and finally the paper is passed between a pair of elastic rolls 2 to obtain the objective single-side mat-coated paper by a simultaneous single pressing process. The obtained paper has a mat surface having a glossiness of <45% measured in conformity with JIS P8142 at an angle of 75 deg. and a gloss-finished surface on the reverse face surface-treated with chilled rolls and having a glossiness of >=45% measured by the above method.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a one-sided matte coated paper, and more particularly to a one-sided matte coated with excellent surface texture and the opposite side having a glossy luster. Is.

[0002]

2. Description of the Related Art A conventional matte coated paper is manufactured by applying the same paint on both sides of a base paper, and after drying, lightly surface-treating both sides with a chilled roll. It has a matte surface. Further, the one developed by the surface treatment using the recently developed hard roughening roll is also a double-sided matte product.

[0003]

DISCLOSURE OF THE INVENTION The present invention is intended to provide a market for a single-sided matte and single-sided gloss coated paper as a new product field. Is, for example, the outer surface of the glossy surface as the cover of a book,
Demand is expected to grow in the future because it has the advantage that the matte side can be used on the back side.

The inventors of the present invention have conducted various studies on the surface treatment after coating the base paper with a coating material and drying the same, and as a result of various studies, a method of simultaneously exhibiting different treatment effects on one surface and the opposite surface is treated. Different types of rolls are used on the front and back sides of the paper. Especially for the matte side, use a roughened roll with an appropriate surface roughness, and for the polished side, use a chilled roll for excellent surface properties. One-sided matte, one-sided matte coated paper is obtained.

[0005]

According to the present invention, one side of coated paper has a surface roughness (R _max ) 8 to 35 defined by JIS B 0601.
The surface is treated with a surface roughening roll of μm, the glossiness measured at an angle of 75 ° according to JIS P 8142 is less than 45%, and the other surface is treated with a chilled roll. It is a one-sided matte coated paper that is said to be 45% or more.

[0006]

The present invention comprises the above-mentioned constitution. More specifically, the one-sided matte coated paper having a gloss of less than 45% on one side and 45% or more on the opposite side is a coated paper. Otherwise, the surface feels bad, so it is not suitable for high-end applications, especially for multicolor printing, and the glossiness of white paper is extremely important in achieving calm printing. It is less than 45%, preferably 40%. This is because the matte effect is obtained below, and conversely, when it is desired to make the printed surface glossy, the glossiness of the white paper needs to be 45% or more, preferably 50% or more.

In the present invention, as a method for simultaneously allowing different surface treatments on one side and the opposite side, a roughening roll is applied to the surface to be matted and a chilled roll is applied to the polished surface. It is the skeleton to apply, but instead of passing it through the nip between the roughening roll and the chilled roll, the combination of the roughening roll and the elastic roll and the combination of the chilled roll and the elastic roll are the same super calender. By arranging the sheets in a different manner and devising the paper passing method, it is possible to impart matte to one side and gloss to the opposite side by one treatment.

In this case, the chilled roll may be a conventional one for double-sided gloss coated paper, but for the surface to be matted, the surface roughness (R
_It is necessary to use a roughening roll having a _{maximum of 8} to 35 μm, preferably 10 to 30 μm. In other words, even if the matte surface is treated with a chilled roll, it will have the same luster as the matte surface. Can only be the same as

Therefore, by using the roughening roll only for the matte surface, it is possible to impart the matte effect to only one surface simultaneously with the chilled roll treatment for the matte surface and under the same pressure.

However, the texture of the matte surface varies depending on the surface roughness of the roughening roll to be used. If it exceeds 35 μm, the surface becomes rough, and if it is less than 8 μm, a satisfactory matting effect cannot be obtained, resulting in uneven gloss. So-called gross mottle is also likely to occur, and the effects of the present invention cannot be exhibited.

The material of the roughening roll is made of steel or an alloy, and its surface is roughened by sandblasting or corrosion, or its surface is plated with chromium. The elastic roll used in combination with the surface-roughening roll and the chilled roll may be a known one such as cotton, asbelt, wool, plastic, etc., but the hardness is Shore D of 80 to 90 °. It is preferable in that a matte surface can be provided.

Further, it is best to press the roughening roll against the matte surface two or more times, and finally press the elastic roll. The surface temperature of the roughening roll, the chilled roll, and the elastic roll during the surface treatment is 60 ° C. or lower, preferably 40.
The temperature is preferably 55 to 55 ° C. Therefore, if necessary, a cooling device to which air cooling, water cooling, etc. are applied is provided.

When the coated paper is pressed and passed through, the press conditions of the nip include the composition of the paint of the coated paper, the roughness of the roughened roll surface, the temperature of the roll, and the gloss required for the product. Although it is determined by a combination of degrees and the like, a pressure in the range of 100 to 300 kg / cm is appropriately selected and used.

The coating liquid pigments used in the present invention include kaolin, calcium carbonate, titanium oxide, aluminum hydroxide, satin white, zinc oxide, barium sulfate, calcium sulfate, calcium sulfite, talc, silica, active. Examples include pigments that are generally used in paints for coated paper, such as clay, diatomaceous earth, and plastic pigments, and those obtained by appropriately selecting and combining these pigments are preferably used.

Further, examples of adhesives for coating liquid include casein, soybean protein, yeast protein, starch, oxidized starch, esterified starch, etherified starch, cationized starch, modified starch such as enzyme-modified starch, and cellulose derivatives. Such as natural adhesives and styrene-butadiene copolymers, methylmethacrylate-butadiene copolymers and other conjugated diene copolymer latexes, acrylic ester, methacrylic acid ester polymers or copolymers and other acrylic polymers Examples include coalescing latex, vinyl acetate-based polymer latex such as ethylene-vinyl acetate copolymer, synthetic adhesive such as polyvinyl alcohol, and one or two of these adhesives.
One or more kinds are used, and 5 to 30 parts by weight are blended per 100 parts by weight of the pigment.

For rotary printing, a latex having a large particle size, a low melting point of a polymer, or a low gel content is commercially available in order to impart blister resistance, and these are appropriately used. It is also effective to increase the strength of the base paper by lowering the ash content of the base paper, which contributes to the improvement of the folding resistance. In preparing the coating liquid of the present invention, various auxiliaries usually used for coated paper such as a dispersant, a flow modifier, an antifoaming agent and a coloring agent are appropriately selected and used as necessary.

In addition, when the different glossinesses required for the product on the front side and the back side cannot be ensured by using the same coating solution on the front and back sides, different coating solutions on the front side and the back side may be used.

The coating method is not particularly limited,
A blade coater, an air knife coater, a bar coater, a roll coater, a chanplex coater, etc., which are used for the production of general coated paper, are appropriately selected and used, and are coated in a single layer or multiple layers, and 3 to 8%. It is dried up to the water content and rolled up.

[0019]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is of course not limited thereto. In the following, parts and% mean parts by weight and% by weight.

Example 1 As a pigment, kaolin [manufactured by Engelhard Minerals and Chemicals (EMC), trade name: Ultra White 90] 50 parts and heavy calcium carbonate having an average particle diameter of 2 μm (manufactured in-house, ground carbonate) 40 parts of calcium, 7 parts of precipitating calcium carbonate (manufactured by Shiraishi Kogyo Co., Ltd., Brilliant 15) and 3 parts of satin white (made in-house) having an average particle diameter of 2 μm are placed in a mixer and oxidized starch ( Oji Constarch Co., Ltd., trade name: Oji Ace A) 5 parts and latex (Asahi Kasei Co., trade name: L-1537) 12 parts, 0.3% sodium polyacrylate as a dispersant per pigment, and calcium stearate 0.5 as a lubricant. % And fluorescent dye 0.2% were sequentially added and thoroughly mixed and dispersed, and then the pH was adjusted to alkaline with a 25% aqueous ammonia solution to produce coated paper.

This coated paper was coated with a blade coater on both sides of a base paper having a basis weight of 80 g / m ² produced by a known Fourdrinier paper machine using a bleached hardwood kraft pulp, 20 g / m ² per side, A coated paper having a paper moisture content of 6% was produced by drying with a known dryer.

Next, the coated paper was one roughening roll having a surface roughness (R _max ) defined by JIS B 0601 of 10 μm,
The back side of the coated paper (the wire side of the paper machine) is roughened with a super calendar A as shown in Fig. 1 in which 4 chilled rolls and 5 elastic rolls with Shore D hardness of 88 ° according to ASTM standard D-2240 are arranged. Pressed twice with the chemical roll 1, pressed the opposite side 5 times with the chilled roll 3, and finally passed between the elastic rolls 2 to simultaneously deluster one side with the same pressure and polish the opposite side. Processed.

At this time, the temperature of the roughening roll 1 was 50 ° C., the nip pressure was 200 kg / cm, and the paper was passed at a speed of 700 m / min.
In FIG. 1, reference numeral 3 is a chilled roll, 4 is a paper roll, and 5 is a coated paper. The quality of the obtained coated paper was evaluated by the following method.

Method of quality evaluation 1) White paper glossiness: Measured at an angle of 75 degrees in accordance with JIS P 8142. 2) Blank two-dimensional surface roughness: Center line average roughness (Ra) using a surface roughness measuring instrument (model: SE-3AK) manufactured by Kosaka Laboratory
It showed with. 3) White paper surface property: Matte-coated paper was visually evaluated, and indicated by ◯, □, Δ, and × in order from the best. ○ □ 、 □
Δ and Δx indicate the middle of each. 4) Surface property after printing: Matte coated paper was printed with a Mitsubishi diamond printer (manufactured by Mitsubishi Heavy Industries, Ltd.) and visually indicated by ◯, □, Δ, and × in order from the best. ◯ □, □ △, and Δx indicate the middle of each.

Example 2 A coating liquid prepared in the same manner as in Example 1 except that kaolin (35 parts), heavy calcium carbonate (55 parts), precipitated calcium carbonate (7 parts) and satin white (3 parts) were used as a pigment. The back side of the base paper to be erased was coated with the coating liquid of Example 1 on the opposite side in the same manner as in Example 1.

The coated paper obtained was subjected to JIS B for roughening roll.
Using the same supercalender as in Example 1, except that the surface roughness defined by 0601 is 32 μm, the surface to be matted is the roughening roll twice, and the surface to be glossed is the chilled roll. Paper is passed so that it hits five times, and the nip pressure is 140K.
Surface treatment was performed at g / cm and a speed of 700 m / min.

Example 3 The coated paper obtained in the same manner as in Example 2 was the same as in Example 2 except that the surface roughness of the roughening roll defined by JIS B 0601 was 25 μm. Was subjected to a surface treatment in the same manner as in Example 2 with a nip pressure of 200 kg / cm.

Comparative Example 1 The coated paper obtained in the same manner as in Example 1 was treated with the super calendar shown in FIG. 2 consisting of 5 chilled rolls having no roughening roll and 5 elastic rolls. It was produced in the same manner as in Example 1.

Comparative Example 2 The coated paper obtained in the same manner as in Example 1 was treated with two roughening rolls having a surface roughness (R _max ) defined by JIS B 0601 of 25 μm, and Example 1 The surface treatment was carried out under the same conditions as in Example 1 using the super calender of FIG. 3 consisting of three chilled rolls and five elastic rolls.

Comparative Example 3 A coated paper was produced in the same manner as in Example 1 except that a roughening roll having a surface roughness of 37 μm defined by JIS B 0601 was used for the surface treatment.

Comparative Example 4 A coated paper was produced in the same manner as in Example 1 except that a surface roughening roll having a surface roughness of 7 μm defined by JIS B 0601 was used.

Table 1 shows the quality evaluation of the coated papers obtained in Examples 1 to 3 and Comparative Examples 1 to 4.

[0033]

[Table 1]

As is clear from Table 1, a roughening roll, a chilled roll and an elastic roll having an appropriate surface roughness were used, and the surface of the coated paper on which the matte treatment was desired was polished on the roughening roll. By subjecting the surface to be treated to a chilled roll for surface treatment, a one-sided matte / one-sided gloss coated paper having an excellent surface texture can be obtained (Examples 1 to 1).
3).

On the other hand, when the coated paper is surface-treated, when a super calender (FIG. 2) having only a chilled roll and an elastic roll is used without a roughening roll, both surfaces show almost the same glossiness. However, one side cannot be matted and one side cannot be glossed (Comparative Example 1).

Also, when both surfaces hit the roughening roll (FIG. 3), both surfaces are both delustered and cannot be matted on one side or polished on one side (Comparative Example 2). One side is a roughening roll, even when the other side hits a chilled roll, if the roughening roll does not have an appropriate surface roughness, the texture of the matte-treated surface is extremely poor, and the effect of the present invention is obtained. It cannot be demonstrated. For example, if the surface roughness of the roughening roll is too rough, the matte surface is rough (Comparative Example 3). On the contrary, if it is too fine, the matting effect is unsatisfactory and gloss mottle easily occurs (Comparative Example 4).

[0037]

INDUSTRIAL APPLICABILITY As described above, the present invention is a coated paper having a matte surface on one side and a glossy surface on the other side and a difference in glossiness between the front and back sides, and is most suitable for the cover of a book. . Further, in the present invention, a roughening roll having an appropriate surface roughness is applied to the surface to be matted and a chilled roll is applied to the opposite surface to be matted, and at the same time surface treatment is performed under the same pressure. As a result, a one-sided matte / one-sided gloss coated paper having an excellent texture can be obtained.

[Brief description of drawings]

FIG. 1 is an explanatory diagram for passing a sheet through an example of a calendar device for producing the present invention.

FIG. 2 is an explanatory diagram for passing a sheet through a calendering device having no roughening roll.

FIG. 3 is an explanatory diagram of a case where both surfaces of the coated paper are pressed against a roughening roll of a calendar to pass the paper.

[Explanation of symbols]

 A, B, C: Super calendar device 1: Roughening roll 2: Elastic roll 3: Chilled roll 4: Paper roll 5: Coated paper

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kusumi Kusumi 373 Yoshioka, Yonago City, Tottori Prefecture Oji Paper Co., Ltd. Yonago Mill

Claims (1)

[Claims] 1. A single-sided coating after the paper is surface treated with a roughening roll surface roughness (R _{ma x)} 8~35μm defined in JIS B 0601, at an angle 75 ° according to JIS P 8142 A one-sided matte coated paper characterized in that the measured gloss is less than 45% and the other surface is surface-treated with a chilled roll and the same gloss as described above is 45% or more.