JP2008261066A - Coated paper for double-sided printing, and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide double-side coated paper responsive to a perfecting press, particularly a double-deck type perfecting press without causing printing double and to provide a method for producing the double-side coated paper. <P>SOLUTION: The coated paper for double-sided printing is obtained by coating the surfaces of base paper prepared by beating raw material pulp at ≤500 ml CSF, Canadian freeness, and at a rate of ≥600 m/min with a coating composition consisting essentially of a pigment and an adhesive, drying the coated paper and then finishing the surfaces. The coated paper for double-sided printing has a ratio (long grain/short grain) of the machine direction to the cross direction of an ultrasonic propagation velocity of 1.0-1.6, measured by a sound velocity method, and the transverse elongation ratio after 5 min immersion in water to the machine direction of the double-side coated paper measured according to J-TAPPI-27(B), is within the range of 2.0-4.0%. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a double-sided sheet-fed printing press, particularly a double-deck type double-sided sheet-fed printing press, and relates to a coated paper for double-sided printing without printing doubling and a method for manufacturing the same.

In recent years, the printing industry has been faced with a harsh market environment such as smaller lots and shorter delivery times, and most of them have introduced double-sided sheet-fed printing presses that can print at the same time front and back at the same time with excellent productivity and efficiency. It became so.
There are three types of double-sided sheet-fed printing presses: (1) reverse type, (2) tandem type, and (3) double-deck type. It was possible to print without problems with the double-sided coated paper that had been used so far (the central part and the end face in the width direction of the base paper / the end face was easy to stretch). (3) Double-deck type double-sided sheet-fed printing machine has more dampening water than (1) and (2) type double-sided sheet-fed printing machines, and the front, back and double-sided coated paper Since dampening water is added to both sides, the paper stretch caused by the dampening water varies, and the halftone dot double where the printing halftone dot of the print double is shifted and overlaps at the position where it is transferred to the blanket of the next printing cylinder after printing. There is a problem.

So far, a method of suppressing printing doubling by adjusting the drying shrinkage, air permeability, and moisture permeability of a coated paper obtained by providing a polyvinyl alcohol coating layer on a base paper or base paper (Patent Documents 1 and 2). However, the applied polyvinyl alcohol is difficult to dry, and the coating liquid applied thereon is also difficult to dry because the penetration of the coating liquid into the base paper layer is suppressed. As a result, it often responds by slowing down the coating speed, which causes a significant deterioration in productivity. This prescription can be obtained by adjusting the ratio of the longitudinal and transverse directions of ultrasonic propagation velocity measured by the sound velocity method and the elongation after water immersion within a certain range. can do.

In addition, as a countermeasure against printing doubling, in order to eliminate variations in paper elongation due to the addition of fountain solution, it is supported by line judgment products that are cut at the same position of the base paper making width. Therefore, it was difficult to cut the sheet with the paper, and there was a demand for the development of double-sided coated paper with the same paper elongation at any position.
JP 2000-45199 A Japanese Patent Laid-Open No. 2003-155562

Provided is a double-sided sheet-fed printing machine, in particular, a double-deck type double-sided sheet-fed printing machine, and a coated paper for double-sided printing without printing duplication and a method for producing the same.

As a result of the above-mentioned circumstances, the present inventors have intensively studied and studied whether it is possible to have uniform paper elongation in the width direction of the base paper, and as a result, wire-shaking is performed when making the base paper used as the base of the coated paper. Using the apparatus, the paper was made with a shaking strength of 1800 to 12000, the ultrasonic wave propagation speed ratio of the base paper was 1.0 to 1.6 (hereinafter referred to as fiber orientation strength), and J-TAPPI-27 (B) Double-coated double-sided sheets by measuring the elongation after 5 minutes of water immersion in the horizontal direction of the double-sided coated paper (hereinafter referred to as elongation in water and description 9 to 2.0 to 4.0%) The inventors have found that a double-sided coated paper suitable for a leaf printing machine can be obtained, and have completed the present invention.

The present invention includes the following configurations.
(1) The raw material pulp is beaten to a Canadian freeness of 500 ml CSF or less, and a coating composition mainly composed of a pigment and an adhesive is coated on a base paper that has been made at a paper making speed of 600 m / min or more, and then dried. In the finished coated paper for double-sided printing, the ratio of the longitudinal direction and the transverse direction (longitudinal / lateral) of the ultrasonic propagation velocity measured by the sound velocity method is 1.0 to 1.6, and J-TAPPI- Double-sided printing in which the elongation after 5 minutes of water immersion in the horizontal direction is in the range of 2.0 to 4.0% with respect to the paper flow direction of the double-sided coated paper measured according to 27 (B) Coated paper.

(2) Using a wire shaking device that adjusts the shaking strength in the range of 1,800 to 12,000, vibrating the wire and making paper at a paper making speed of 600 m / min or more to obtain a base paper; Coated paper for double-sided printing, which has a step of applying a coating liquid containing a pigment and an adhesive and drying to obtain a coating layer and a step of smoothing the surface of the coating layer Manufacturing method.

  The present invention provides a coated paper for double-sided printing in which the double-sided coated paper has a uniform elongation and does not cause printing doubly even in a double deck type double-sided sheet-fed printing machine having a large amount of dampening water.

The double-deck type coated paper for double-sided sheet-fed printing of the present invention forms a base paper with a high-speed paper machine with a paper making speed of 600 m / min or more, and has a pigment and an adhesive as main components on the base paper. Unlike the conventional wire shaking device, this paper machine is characterized in that it is manufactured by applying a surface finish after coating and drying the coating composition. A device (Duo-shake / manufactured by Voith Co., Ltd.) is provided, and the shaking strength is adjusted to 1800 or more, preferably 3000 or more, more preferably 3500 or more. The shaking strength here is an index representing the energy of shaking represented by the following formula 1, and the larger the value, the larger the shaking energy. When shaking is performed, the pulp fibers are redispersed on the paper machine to improve the formation, and the pulp fibers oriented in the papermaking direction are randomized. When the shaking strength is adjusted to 1800 or more, even a paper machine having a paper making speed of 600 m / min or more can produce a base paper suitable for double-sided coated paper for double-sided sheet-fed printing machines. Incidentally, if the shaking strength is less than 1800, fiber orientation strength and elongation in water suitable for a double deck type double-sided sheet-fed printing press cannot be obtained. In addition, the upper limit of the shaking strength is not particularly defined, and is mainly limited by manufacturing conditions such as paper making speed and facilities such as breast roll weight, but the upper limit of the shaking strength is considered to be about 6000.

I = f ² × s / V (Equation 1)
I: Shaking strength f: Vibration frequency (times / minute)
s: Amplitude (mm)
V: Paper making speed (m / min)

In addition, as a result of various studies on the shaking conditions, the present inventors have found that, as a double-deck type coated paper for double-sided sheet-fed printing presses, the vibration frequency is increased by increasing the amplitude even at the same shaking strength. It has been found that the fiber orientation strength and the elongation in water are excellent when the amplitude is adjusted to 10 mm or more, preferably 15 mm or more, and more preferably 20 mm or more.
The upper limit of the shaking strength of the vibration frequency is determined depending on the equipment capacity, and the maximum value of the vibration frequency is naturally determined when the amplitude is determined, but it is desirable that the vibration frequency is adjusted in the range of 300 to 500 times / minute.

  As a result of intensive studies on characteristics suitable for double-sided coated paper for double-deck type double-sided sheet-fed printing presses, the fiber orientation strength of the base paper is 1.6 or less, preferably 1.5 or less, more preferably 1.0. When the double-coated paper sheet is adjusted so that the elongation in water of the double-coated paper product is 4.0% or less, preferably 3.0 or less, more preferably 2.0 to 2.5, It has been found that it is excellent in the countermeasure against halftone dot duplication of the printing press. When the underwater elongation exceeds 4.0%, the elongation of the paper becomes large, and the double is generated during printing. Moreover, it is difficult to make the underwater elongation 2.0% or less as a characteristic of paper. As a method of adjusting the fiber orientation strength and the elongation in water, not only the shaking device, but also the ratio of the flow rate of the paper to the wire and the wire speed (commonly called J / W ratio = jet / wire ratio) And the head box L / b value can be obtained by adjusting to the optimum conditions of the paper machine.

Examples of the cellulose fiber raw material forming the base paper include chemical pulps such as kraft pulp (KP), sulfite pulp (SP) and soda pulp (AP), semi-chemical pulp (SCP), and chemiground wood pulp (CGP). Semi-chemical pulp, ground pulp (GP), thermo-mechanical pulp (TMP, BCTMP) and other mechanical pulp, non-wood pulp made from cocoon, coconut, hemp, kenaf, etc., deinked pulp made from waste paper Is mentioned. These may be used alone or in combination of two or more.

In the present invention, a single pulp or a mixture of the above pulps is used after being beaten to a Canadian freeness of 500 ml CSF or less. Although it is preferable to proceed with beating for strength improvement, the fiber orientation is increased even if the pulp has been beaten by using the wire seeking device of the present invention, because the stretchability is increased and printing duplication is likely to occur. Is adjusted, and elasticity is suppressed.

In the base paper of the present invention, various fillers generally used for paper as necessary as fillers such as kaolin, calcined kaolin, calcium carbonate, calcium sulfate, barium sulfate, titanium dioxide, talc, zinc oxide, alumina, carbonate Mineral pigments such as magnesium, magnesium oxide, amorphous silicate, bentonite, zeolite, sericite, smectite, styrene resin, urea resin, melamine resin, acrylic resin, vinylidene chloride resin and their fine hollow particles Organic fillers such as may be added.

As the internal size of the base paper of the present invention, rosin type sizing agent such as rosin emulsion, alkyl ketene dimer type sizing agent, alkenyl succinic anhydride type sizing agent, stearic anhydride type sizing agent, petroleum resin type sizing agent, wax type There are sizing agents or cationic synthetic sizing agents. Examples of the surface sizing agent include various starches, polyacrylamide, polyvinyl alcohol, cellulose derivatives, acrylic esters, latex, α-olefin maleic anhydride copolymers, styrene acrylic copolymers, and higher fatty acid types. Examples thereof include a synthetic sizing agent and a cationic synthetic sizing agent. In the paper stock, various anionic, nonionic, cationic or amphoteric yield improvers, drainage improvers, paper strength enhancers, etc., various paper additives, dyes, Internal additives for papermaking such as fluorescent brighteners, pH adjusters, antifoaming agents, pitch control agents, slime control agents and the like can be appropriately added. The papermaking pH conditions are not particularly limited, and may be acidic or alkaline papermaking. Since the present invention is characterized by performing wire shaking, a base paper having a base paper weight of about 30 to 200 g / m ² is manufactured using a paper machine such as a long net paper machine or an on-top former. Usually, surface sizing is performed in an on-machine state.

The method for sizing the surface sizing agent on the surface of the base paper is not particularly limited. For example, a two-roll or rod metalling type size press, a gate roll, a bill blade, a short dwell coater, a roll coater, an air knife coater. Various devices such as a blade coater and a spray can be used as appropriate.

The double-deck type coated paper for double-sided sheet-fed printing machine according to the present invention has a coating layer having a printability and a glossiness on the surface of the coating layer because it is intended for a particularly high-quality printing finish. It is important to increase the degree and smoothness. As a pigment constituting the coating layer, for example, for coated paper such as clay, kaolin, light calcium carbonate, heavy calcium carbonate, titanium dioxide, satin white, barium sulfate, aluminum hydroxide, zinc oxide, plastic pigment, etc. Commonly used pigments are used.

Examples of the adhesive used in the coating layer together with the pigment include proteins such as casein and soybean protein; conjugated diene polymer latex such as styrene / butadiene copolymer and methyl methacrylate / butadiene copolymer. Acrylic polymer latex such as a polymer or copolymer of acrylic acid ester and / or methacrylic acid ester, ethylene / vinyl acetate polymer latex; or these various polymer latexes containing functional groups such as carboxyl groups. Polymer-modified alkali-soluble or alkali-insoluble polymer latex; synthetic resin adhesives such as polyvinyl alcohol, olefin / maleic anhydride resin, melanin resin; enzyme-modified starch, oxidation-modified starch, cationization Starch such as starch; carboxymethyl cellulose, hydroxyethyl cellulose Scan, etc. cellulose - one or more usual coated paper for adhesives, such as such as scan derivative is appropriately selected and used. Generally, the total amount of the adhesive is about 5 to 40 parts by weight with respect to 100 parts by weight of the pigment, and is usually adjusted in the range of 10 to 35 parts by weight.

In addition, in the coating composition mainly composed of a pigment and an adhesive as described above, various auxiliaries such as an antifoaming agent, a coloring agent, and a flow modifier are appropriately added. As an auxiliary for promoting the solidification of the construction layer, for example, an amine, amide, polyacrylamine or the like or a salt of a polyvalent metal such as zinc, aluminum, magnesium, calcium, barium or the like is added in an amount of 0.1 to 10 parts per 100 parts by weight of the pigment. About part by weight can also be added.

The coating composition comprising the above composition is used in the production of general coated paper, for example, a blade coater, an air knife coater, a roll coater, a brush coater, and a katenko. -On-machine or off-machine coater equipped with coating equipment such as coater, champlex coater, bar coater, gravure coater, size press coater, etc. Alternatively, it is applied in multiple layers. The solid content concentration of the coating composition at that time is generally about 40 to 75% by weight, but considering the operability and the like, the range of 45 to 70% by weight is preferable. Per side 5 to 30 g / ^{m 2} as coated amount of the coating layer is preferably in the range of 8~25g / ^{m 2} considering the quality and operability and the like.

As a method for drying the wet coating layer, conventionally known steam heating, hot air heating, gas heater heating, electric heater heating, infrared heater heating, high frequency heating, laser heating, and the like are known. Various methods such as thermal heating and electron beam heating can be appropriately employed.

Thus, the double-deck type double-sided sheet-fed printing press-coated double-sided printing paper coated on the base paper as described above has a surface finish such as smoothing after the coating layer has dried. As a smoothing device, for example, a metal roll such as a super calender or a gloss calender or various calenders composed of a drum and an elastic roll can be used for on-machine and off-machine specifications. Used as appropriate. The moisture content of the coated paper before entering the nip of the calendar is preferably about 3 to 10%, and the finishing speed of the calendar varies greatly depending on the paper basis weight, varieties, etc., but is generally about 100 to 1300 m / min. Adjusted in range. Further, as a surface finishing method, gloss finishing may be performed by pressing the cast drum while the coating layer is wet, such as a wet casting method, a rewet casting method, or a gelled casting method.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. In the examples, “parts” and “%” mean “parts by mass” and “% by mass” unless otherwise specified.

Example 1
NBKP 10% (freeness / CSF = 480 ml) and LBKP 90% (CSF = 460 ml) were used as the pulp, and alkenyl succinic anhydride sizing agent 0.02% (Fibran 81K / Arakawa Chemical Industries), sulfuric acid band A pulp slurry was prepared by adding 0.5% and 10% self-produced calcium carbonate as a filler, and a base paper was made at a speed of 650 m / min by neutral paper making using an on-top former. As conditions at this time, the J / W ratio was set to 0.990, the wire shaking was set to an amplitude of 24 mm, and a vibration frequency of 350 times / minute (shaking strength of 4,523). On the other hand, the base paper at this time was subjected to surface sizing with an on-machine specification two-roll size press. That is, a size press solution composed of 5% of enzyme-modified starch and 0.02% of a styrene / methacrylic acid copolymer surface sizing agent (Polymarlon 1308S / Arakawa Chemical Industries) is adjusted to a solid content of 2.2 g / m ^2. The base paper of 65 g / m < ² > was obtained by coating. In addition, the fiber orientation strength of this base paper was 1.29, and the underwater elongation after 2 minutes of the cross was 2.45.

Next, 100 parts of heavy calcium carbonate (trade name: FMT-90 / manufactured by Phimatech), 10 parts of oxidized modified starch (trade name: Ace A / manufactured by Oji Cons) (solid content), styrene-butadiene copolymer An undercoat coating composition liquid having a solid content concentration of 65% consisting of 5 parts of latex (trade name; manufactured by T-2581A / JSR) was prepared, and kaolin (trade name; UW-90 / Engel) was used as the topcoat coating composition. Hard part) 60 parts, heavy calcium carbonate (trade name; FMT-90 / Pimatec) 40 parts, oxidized modified starch (trade name; Ace A / Oji Cons) 3 parts (solid content), styrene -A coating composition liquid having a solid content concentration of 65% consisting of 12 parts of butadiene copolymer latex (trade name; manufactured by T-2581A / JSR) was prepared. This coating composition solution was coated on both sides using a blade coater and dried so that the coating amount after drying (undercoating / overcoating) was 10/10 g / m ^{2 on} one side of the base paper obtained above. Thereafter, a smoothing process was performed using a super calender to obtain a coated paper for double-sided printing having a weight of 104.7 g / m ² .

Example 2
A coated paper for double-sided printing was obtained in the same manner as in Example 1, except that the paper making speed was 800 m / min, the wire shaking conditions were 24 mm amplitude, and the vibration frequency was 350 times / min (shaking strength 3,675). .

Example 3
A coated paper for double-sided printing was obtained in the same manner as in Example 1 except that the paper making speed was 800 m / min, the wire shaking conditions were 17 mm in amplitude, and the vibration frequency was 350 times / min (shaking strength 2,603). .

Example 4
A coated paper for double-sided printing was obtained in the same manner as in Example 1 except that the paper making speed was 800 m / min, the wire shaking conditions were 12 mm amplitude, and the vibration frequency was 400 times / min (shaking strength 2,400). .

Example 5
A coated paper for double-sided printing was obtained in the same manner as in Example 1 except that the paper making speed was 800 m / min, the wire shaking conditions were amplitude 9 mm, and the vibration frequency was 550 times / min (shaking strength 3,403). It was.

Comparative Example 1
A coated paper for double-sided printing was obtained in the same manner as in Example 1 except that the paper making speed was 800 m / min and no wire shaking was performed.

Comparative Example 2
A coated paper for double-sided printing was obtained in the same manner as in Example 1 except that the paper making speed was 800 m / min, the wire shaking conditions were 9 mm amplitude, and the vibration frequency was 185 times / min (shaking strength 385).

Comparative Example 3
A coated paper for double-sided printing was obtained in the same manner as in Example 1 except that the paper making speed was 650 m / min, the wire shaking conditions were amplitude 9 mm, and the vibration frequency was 250 times / minute (shaking strength 865).

  The double-sided coated papers obtained in Examples 1 to 5 and Comparative Examples 1 to 3 were evaluated as follows, and the evaluation results are shown in Table 1.

-Ratio of ultrasonic propagation speed in vertical and horizontal directions The ratio of ultrasonic propagation speed in the vertical and horizontal directions of the base paper was measured with SST-3000 (Sonic Sheet Tester) manufactured by Nomura Corporation.

-Elongation of paper in water Using a Fencer stretch tester manufactured by Kumagai Riki Kogyo Co., Ltd., the elongation percentage of the paper after 5 minutes was measured according to J-TAPPI-27 (B).
The paper with less elongation is less stretched.

- dot doubling Evaluation 1) Kikuban wales double-sided coated paper 104.7g / ^{m 2} after printing when both sides of sheets of double-deck type-fed printing press of 1,000 sheets / a, printing the end portion (the tail edge portion) The size of the halftone dots of the black ink was measured using a printing double measuring device manufactured by MHI Solution Technology.
The larger the halftone dot size, the larger the halftone dot double.

2) The sensory evaluation of the printed matter was performed with a 15-fold magnifier.
○: There is no halftone dot.
Δ: Some halftone dots are observed.
X: Mostly halftone dots are observed.

Claims (2)

The raw material pulp is beaten to 500 ml CSF ml or less by Canadian Freeness, and the coating composition mainly composed of pigment and adhesive is coated on the base paper that has been made at a paper making speed of 600 m / min or more, dried, and then surface-finished. In the coated paper for double-sided printing, the ratio of the longitudinal direction and the transverse direction (longitudinal / lateral) of the ultrasonic propagation velocity measured by the sound velocity method is 1.0 to 1.6, and J-TAPPI-27 ( B) with respect to the paper flow direction of the double-sided coated paper measured in accordance with B), the elongation after 5 minutes after water immersion in the transverse direction is in the range of 2.0 to 4.0%. Coated paper for duplex printing. Using a wire shaking device that adjusts the shaking strength in the range of 1,800 to 12,000, vibrating the wire and making paper at a paper making speed of 600 m / min or more to obtain a base paper, and a pigment on the base paper And a coating liquid containing an adhesive and drying to obtain a coating layer, and a step of smoothing the surface of the coating layer. A method of manufacturing paper.