JP4998131B2 - Manufacturing method of coated paper - Google Patents

Description

The present invention uses a rod metering size press type coating apparatus, improves operability, which is a problem in the manufacturing process of coating a coating solution under high-speed conditions, and coated paper for offset printing excellent in quality. It is in providing the manufacturing method and coated paper of this.

In recent years, the demand for coated paper for printing has increased in the commercial printing field for the purpose of advertising and advertising such as flyers, catalogs, pamphlets and direct mail. Although these commercial printed materials have low commercial value, it is important that the purpose is achieved as an advertising medium, and therefore, there is a demand for low-cost and high-quality printed products. In order to meet such demand for coated paper, paper manufacturers are working to increase the width and speed of coating equipment in order to increase productivity and reduce costs while maintaining high quality. Under such circumstances, it is an important technical issue to increase productivity while maintaining high quality.
Conventional coated paper production methods include the off-machine coating method in which papermaking and coating are performed in separate processes, and the on-machine coating method in which papermaking and coating are performed simultaneously on a single machine. The coating method can reduce the manufacturing cost of the product and has the feature that a product with price competitiveness can be manufactured.
As described above, in order to further improve productivity in recent years, attempts have been made to produce products at a higher speed with an on-machine coating apparatus. Generally, a gate roll coater or a rod metering size press coater, which is a film transfer system, is used as an on-machine coating apparatus. Using these coaters, a pigment coating liquid usually containing a pigment and an adhesive is applied. Double coated paper that is coated with a pigment coating solution is produced at high speed using a blade coating type coater on the fine coated paper. It is demanded. In the film transfer method, since there is no problem of boiling, it is preferable to use a rod metering size press coater.
If such a pigment coating solution is applied at a higher speed with an on-machine coating device, a mist generation trouble may occur in which the coating solution mists and scatters at the applicator roll nip exit. It tends to occur at a speed of 1300 m / min or more. In order to solve these problems, various proposals have been made (see Patent Documents 1 to 3).

Japanese Patent Laid-Open No. 10-46496 JP-A-9-324395 JP-A-9-170195

On the other hand, with regard to the improvement of productivity, particularly when manufacturing low-basis weight coated paper, the above-mentioned rod metering size press coater is used to apply a pigment coating solution containing a pigment and an adhesive. Instead, after using a clear coating solution such as starch, it may be possible to produce coated paper at a high speed using a blade coating method. However, when a clear coating solution such as starch is applied with a rod metering size press coater at a papermaking speed of 1300 m / min or more, mist is generated and there is a problem in operability.
In view of the situation as described above, an object of the present invention is to use a rod metering size press type coating apparatus and apply a clear coating solution under high speed conditions, particularly at a high speed condition of 1300 m / min or more. It is an object of the present invention to provide a method for producing a coated paper for printing and a coated paper, which are improved in operability, which is a problem, and excellent in quality after top coating.

In a method for producing a coated paper in which a coating liquid containing a pigment and an adhesive is coated and dried on a base paper to provide one or more coating layers, the papermaking speed is 1300 m / min or more, and the undercoating For the work, a rod metalling size press-type coating device having a grooved rod with a rod groove width of 0.30 mm or less was used, and 0.5 g / m ² or more of starch coating solution was applied on both sides, and a pigment was added. And a coating liquid comprising an adhesive and a method for producing a coated paper.

By using the rod metering size press type coating device according to the present invention, improvement in operability, which is a problem in the manufacturing process in which the coating liquid is applied at a high speed condition, and offset with excellent quality such as blister resistance. A coated paper for printing and a method for producing the same can be obtained.

In the present invention, a paper coating speed is 1300 m / min or more, and a starch coating is performed using a rod metering size press type coating apparatus having a grooved rod with a rod groove width of 0.30 mm or less on the base paper. This is a method for producing coated paper, characterized in that a coating liquid having a pigment and an adhesive is further applied after coating the liquid on both sides at 0.5 g / m ² or more.
Further, the present invention provides a method for producing a coated base paper in which a clear coating solution is applied and dried on a base paper, and the paper making speed is 1300 m / min or more and the groove width of the rod is 0.30 mm or less. A method for producing a coated base paper, wherein a starch coating solution is coated on both sides at 0.5 g / m ² or more using a rod metering size press type coating device having a rod.
When an on-machine coater is used to manufacture at a high speed of 1300 m / min or more and a large amount of starch coating solution is applied to the undercoat, there is a problem that mist is likely to occur.
In order to solve this problem, as a result of repeated studies on the shape of the rod, when the starch coating solution is operated under a high speed condition of 0.5 g / m ² or more on both sides and a paper making speed of 1300 m / min or more, 0.30 mm By using the following groove width, mist does not occur, paper breakage hardly occurs, drying load is reduced, and operability is improved.
As these mechanisms, when a rod having a narrow groove width is used, the coating film formed on the applicator roll is thin, and almost 100% is transferred to the base paper, so that almost no mist is generated. On the other hand, if the groove width is wide, the film thickness of the paint formed on the applicator roll becomes large, and an excessive amount that is not transferred to the base paper is likely to be generated, which is presumed to be generated as mist.
The pulp raw material of the coated base paper of the present invention is not particularly limited, and is generally used as a papermaking raw material for printing paper such as mechanical pulp (MP), deinked pulp (DIP), and softwood kraft pulp (NKP). Any one may be used as long as it is used, and one or two or more of these may be used as appropriate. Examples of mechanical pulp include groundwood pulp (GP), refiner groundwood pulp (RGP), thermomechanical pulp (TMP), chemithermomechanical pulp (CTMP), chemiground pulp (CGP), and semi-chemical pulp (SCP). . The deinked pulp may be any deinked pulp made from high-quality paper, medium-quality paper, low-grade paper, newspaper, flyers, magazines, etc., or unselected waste paper mixed with these. Absent. In the present invention, even when the mechanical pulp is 10% by weight or more with respect to the pulp, effects such as good blister resistance and less roughening can be exhibited.
The filler used in the present invention can be arbitrarily used known, for example, heavy calcium carbonate, light calcium carbonate, clay, silica, light calcium carbonate-silica composite, kaolin, calcined kaolin, deramikaolin, magnesium carbonate, Inorganic fillers such as amorphous silica produced by neutralization by mineral production of barium carbonate, barium sulfate, aluminum hydroxide, calcium hydroxide, magnesium hydroxide, zinc hydroxide, zinc oxide, titanium oxide, sodium silicate, Organic fillers such as urea-formalin resin, melamine resin, polystyrene resin and phenol resin can be used alone or in combination. Among these, calcium carbonate and light calcium carbonate-silica composite, which are typical fillers for neutral papermaking and alkaline papermaking, are preferably used. The filler content in the paper is 1-40% solids by weight. From the viewpoint of improving the surface property, the filler content in the paper is preferably 10 to 40% by weight, more preferably 12 to 35% by weight.

As the internal additive, chemicals such as a dry paper strength improver, a wet paper strength improver, a drainage improver, a dye, and a neutral sizing agent may be used as necessary. Examples of the dry paper strength improver include polyacrylamide and cationized starch, and examples of the wet paper strength improver include polyamidoamine epichlorohydrin. These chemicals are added within a range that does not affect the formation and operability. Examples of neutral sizing agents include alkyl ketene dimers, alkenyl succinic anhydrides, and neutral rosin sizing agents.
As the paper machine used for the coated base paper of the present invention, a normal paper machine such as an on-top former or a gap former is used. However, the paper jetted from the head box is sandwiched between two wires and travels. It is more suitable to use a gap former type paper machine that dehydrates almost evenly from both sides of the wet paper at a high paper making speed of 1300 m / min or more, preferably 1500 m / min or more, more preferably 1600 m / min or more. About 2500 m / min. Also, among the gap former paper machines, the use of a roll and blade former type gap former paper machine having a dewatering mechanism with a dewatering blade immediately after the initial dewatering with the forming roll further reduces the occurrence of roughening, and the front and back sides. Good surface properties with no difference can be obtained. Further, the press part of the paper machine of the present invention preferably uses a shoe press. When the paper making speed is high, it is preferable to process a tandem type shoe press in one or more stages in consideration of moisture after pressing. Preferably, the interlayer strength and blister resistance are improved by treating in two or more stages. The processing conditions of the shoe press are preferably 100 KN / m to 1100 KN / m, more preferably 500 KN / m to 1100 KN / m. When two or more shoe presses are used, passing the paper so that the transfer belt is in contact with the shoe press on the dryer part side is less likely to cause paper breakage and has excellent high-speed operability.

The paper machine pre-dryer and after-dryer can also use a public apparatus, and the drying conditions are not particularly limited, and can be appropriately set within the normal operating range.
In the present invention, on the base paper made as described above, a rod metering size press type coating apparatus is used, and the starch coating solution is applied on both sides at a high speed of 0.5 g / m ² or more and 1300 m / min or more. When coating, there is no occurrence of mist, paper breakage is difficult to occur, the drying load is reduced, and good operability is obtained, so it is necessary to use a grooved rod with a rod groove width of 0.30 mm or less There is also a smooth plain rod. The rod width is preferably 0.05 to 0.30 mm, more preferably 0.05 to 0.20 mm, and still more preferably 0, from the viewpoint of improving the strength because it is easy to suppress the mist and apply the starch. 0.05 to 0.15 mm. The rod diameter is preferably 10 to 50 mm from the viewpoint of coating suitability. In the case of a rod having a diameter smaller than 10 mm, the film-forming ability of starch is lowered and the surface shape tends to be inferior.
The starch coating solution of the present invention is a clear coating solution containing starch as a main component, and contains 50% by weight or more, preferably 80% by weight or more of starch as a solid content. As the starch used, starch such as oxidized starch, hydroxyethyl etherified starch and enzyme-modified starch can be used alone or in combination. Moreover, polyacrylamide, polyvinyl alcohol, etc. can also be mixed and used. If necessary, auxiliary agents such as surface sizing agents, water-resistant agents, water-retaining agents, thickeners, lubricants, etc. may be added. From the viewpoint of blister resistance and roughening, the starch coating solution may be applied. Koryou is at 0.5 g / ^{m 2} or more, preferably from 0.5 to 4.0 g / ^{m 2,} more preferably from 1.0 to 3.0 g / ^{m 2.}
In the present invention, on the base paper, using a rod metering size press type coating apparatus, after applying a starch coating solution of 0.5 g / m ² or more on both sides, a top coating having a pigment and an adhesive. Apply liquid.

According to the desired quality, the topcoat coating solution is used by appropriately changing the pigment in the paint, the type of the adhesive, or the amount ratio of the pigment to the adhesive.
As the pigment used in the pigment coating layer of the present invention, conventionally used kaolin, clay, delaminated clay, heavy calcium carbonate, light calcium carbonate, talc, titanium dioxide, barium sulfate, calcium sulfate, oxidation Inorganic pigments such as zinc, silicic acid, silicate, colloidal silica, and satin white, and organic pigments such as plastic pigments can be used alone or in combination of two or more. As the adhesive used in the pigment coating layer of the present invention, conventionally used styrene / butadiene, styrene / acrylic, ethylene / vinyl acetate, butadiene / methyl methacrylate, vinyl acetate / butyl acrylate, etc. Synthetic adhesives such as polyvinyl alcohol, maleic anhydride copolymer, acrylic acid / methyl methacrylate copolymer, casein, soybean protein, synthetic protein proteins, oxidized starch, positive starch, urea Appropriate selection of one or more common adhesives for coated paper such as phosphated starch, etherified starch such as hydroxyethyl etherified starch, starches such as dextrin, cellulose derivatives such as carboxyethylcellulose, hydroxyethylcellulose, hydroxymethylcellulose Used. These adhesives are used in an amount of about 5 to 50 parts by weight, more preferably about 5 to 25 parts by weight per 100 parts by weight of the pigment. In addition, various assistants to be blended in ordinary coating paper coating compositions such as dispersants, thickeners, water retention agents, antifoaming agents, water resistance agents, colorants, and printability improvers as necessary. Agents are used as appropriate.

The coating amount of the overcoat coating layer of the present invention, preferably per side 2 to 30 g / ^{m 2,} more preferably from 5 to 15 g / ^{m 2,} more preferably from 5~12g / ^{m 2.}
The coated paper thus obtained can be subjected to a calendar process. The calendar process may be a super calendar, a gloss calendar, a soft calendar, or the like that is usually used for smoothing coated paper, and these may be used in combination. The treatment temperature of the calendar is preferably 100 ° C. or higher, and more preferably 150 ° C. or higher.
In the present invention, mist is generated when producing coated paper using an on-machine coater in which a coating layer containing a pigment and an adhesive is coated and dried on a base paper to provide a coating layer. Accordingly, it is possible to produce a coated paper for printing that is less likely to break paper, reduces the drying load, improves operability, and has excellent blister resistance and roughening suppression. In addition to papermaking and coating, productivity can be improved by further adding a calendar process and integrating them, and continuously feeding the paper to produce coated paper.

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to the examples. In addition, unless otherwise indicated, all the parts and% shown in an Example mean the solid content weight part and solid content weight%.
<Evaluation methods>
(1) High-speed operability: The suitability of high-speed operability was evaluated, with no mist generated during coating and low drying load.
◎ Very good, ○ Good, △ Slightly bad, × Bad (2) Blister resistant RI-I type printing machine (Ming Seisakusho), offset printing ink (Toyo Ink Manufacturing Co., Ltd .: TK Mark V617) Was used, and both sides were printed at a constant ink amount of 0.8 cc, and the humidity was adjusted all day and night. The test piece was then immersed in a constant temperature oil bath set at a temperature of 140 ° C., and the occurrence of blisters was visually determined.
◎ = Not generated at all, ◯ = Not generated at all, Δ = Generated, × = Significantly generated (3) Roughing Measured with a paper surface analyzer FIBRO1000 manufactured by Fibro. This measuring instrument is a measuring instrument that applies water to the surface of a sample, and after drying with an infrared lamp, evaluates the degree of swell of surface fibers by performing image analysis with a CCD camera. The measurement was performed under the conditions of a water application amount of 8.0 g / m 2 and a drying temperature of 150 ° C., and the roughening amount was evaluated by a Qty value (lines / m) that is the number of fibers raised to 0.1 mm or more from the reference line (Qty The smaller the value, the better the roughening.)
[Example 1]
Light calcium carbonate as a filler is added to a pulp slurry consisting of 70 parts of LBKP and 30 parts of DIP (containing 35% by weight of TMP), and 4 parts of cationized starch is added as an internal paper strength agent. The paper stock was adjusted. Using this stock, paper was made at 1700 m / min with a roll and blade former type gap former type paper machine having two tandem shoe presses, followed by a rod with a rod groove width of 0.10 mm (rod diameter 15 mm). Using an on-machine rod metering size press equipped with a coating of 1.6 g / m ² of oxidized starch solution with a solid content of 10% on both sides, and drying, a 45.6 g / m ² coated base paper is obtained. It was. Next, 100 parts of pigment containing 73 parts of heavy calcium carbonate and 27 parts of kaolin were mixed with 4.5 parts of oxidized starch and 8.2 parts of carboxy-modified styrene / butadiene copolymer latex as an adhesive. A coating solution having a partial concentration of 64% was prepared, and 8.3 g / m ² per side of the base paper was overcoated on both sides and dried.
Further, a high temperature soft calender of 2 rolls and 6 stacks having an elastic roll with a Shore D hardness of 91 ° was used, and all the 1 to 6 nips were calendered under conditions of a metal roll surface temperature of 150 ° C. and a linear pressure of 400 kN / m.
[Example 2]
In Example 1, instead of using a rod groove width of 0.10 mm, a coated paper was prepared in the same manner as in Example 1 except that 1.6 g / m 2 of oxidized starch was applied using a rod groove width of 0.30 mm. Manufactured.
[Comparative Example 1]
In Example 1, instead of using a rod groove width of 0.10 mm, a coated paper was prepared in the same manner as in Example 1 except that 1.6 g / m 2 of oxidized starch was applied using a rod groove width of 0.40 mm. Manufactured.
[Comparative Example 2]
In Example 1, coated paper was produced in the same manner as in Example 1 except that 0.3 g / m ^{2 was} applied instead of 1.6 g / m ^{2 of} oxidized starch.
Table 1 shows the results.

As is clear from Table 1, the coated paper for printing of the present invention showed little occurrence of mist, excellent high-speed operability, blister resistance and roughening compared to the comparative example. On the other hand, although Comparative Example 1 was excellent in blister resistance and roughening, mist generation was remarkable and high-speed operability was inferior. Moreover, although the comparative example 2 is excellent in high-speed operation property, it is inferior to blister resistance and roughening.

Claims (4)

In a method for producing a coated paper in which a coating liquid containing a pigment and an adhesive is applied and dried on a base paper to provide one or more coating layers, the paper making speed is 1300 m / min or more, For undercoating, a rod metering size press type coating device having a grooved rod with a rod groove width of 0.10 to 0.30 mm is used, and 0.5 g / m ² or more of starch coating solution is applied on both sides. A method for producing a coated paper, characterized in that a coating liquid having a pigment and an adhesive is applied. 2. The coating according to claim 1, wherein the base paper is made using a gap former type paper machine which is a roll and blade former type having a dewatering mechanism with a dewatering blade immediately after initial dewatering with a forming roll. Paper manufacturing method. The method for producing coated paper according to claim 2, wherein the gap former type paper machine has one or more tandem shoe presses. In a manufacturing method of a coated base paper in which a clear coating liquid is applied and dried on a base paper, the paper making speed is 1300 m / min or more, and the groove width of the rod is 0.10 to 0.30 mm. A method for producing a coated base paper, characterized in that a starch coating solution is coated on both sides at 0.5 g / m ² or more using a rod metering size press type coating device.