JP4890876B2 - Water-based gravure coated paper - Google Patents

Description

  The present invention relates to a coated paper for aqueous gravure printing which has good dimensional stability and excellent water gravure printing suitability.

  Patent Document 1 relates to a water-based gravure paper for building materials that is free from shrinkage of paper and wrinkles associated therewith, can prevent paper breakage, has excellent acceptability of water-based ink, and has a good appearance. The configuration is a paper that is bonded to the plywood surface and is gravure-printed with water-based ink on the surface, L-BKP: N-BKP = 75: 25-95: 5, freeness exceeding 200 mlcsf, 300 mlcsf Paper making with sizing agent as 20-40kg / T, paper strength enhancer as 185-220kg / T, wet paper strength enhancer as 35-45kg / T, sulfate band as 44-55kg / T as main internal additives The technology is described.

Patent Document 2 relates to a coated paper for water-based gravure printing that has good smoothness and glossiness of the coated paper and has excellent printability with a water-based gravure ink. The composition is a coating containing 20 to 80 parts by weight of kaolin having an average particle diameter of 1.0 to 2.0 μm and 80 to 20 parts by weight of cubic light calcium carbonate having an average primary particle diameter of 0.15 μm or less as a pigment component. An aqueous gravure coated with a coating solution containing 0.2 to 0.7 parts by weight of a dispersant as an auxiliary agent and 10 to 15 parts by weight of a latex as an adhesive with respect to 100 parts by weight of the composition. A coated paper for printing, wherein the water-based gravure-printed coated paper has an absorption coefficient Ka of 0.23 ml / m ² · ms ^1/2 or more measured using a Bristow tester and distilled water as an evaluation liquid. A water-based gravure-coated paper characterized by being.

Patent Document 3 relates to a coated paper for printing suitable for gravure printing using water-based ink. The composition is a printing coated paper in which a pigment coating layer mainly composed of a pigment and an adhesive is provided on at least one side of a base paper. As a characteristic of the coated paper, a water absorption amount at a contact time of 25 milliseconds is used. Is 10 ml / m ² or less, and the contact angle 0.1 seconds after water is dropped on the pigment coating layer of the coated paper is 75 degrees or less. TAPPI Paper Pulp Test Method No. 5. The coated paper for printing having the Oken type air permeability described in 5 above of 10,000 seconds or more.

Patent Document 4 relates to a cast-coated paper excellent in water-based gravure printing aptitude as a gravure printing paper, in particular, excellent in ink drying property and ink coloring property. The composition is a cast-coated paper provided with a coating layer comprising a pigment, a water-soluble and / or water-dispersible adhesive as a main component, and a specific sedimentation volume occupying 100 parts by weight of the total pigment as a pigment is 1.20 ml / g. The ratio of the above pigment is 10 to 80 parts by weight, and contains at least 1 to 30 parts by weight of an aqueous urethane resin as a water-soluble and / or water-dispersible adhesive per 100 parts by weight of the pigment. It is related with the cast coat paper for water-based gravure printing characterized by performing the cast finish after providing the coating layer which contains 1-25 weight part per 100 weight part of pigments.
Japanese Patent No. 3103631 JP 2004-043991 A JP 2003-201697 A Japanese Patent No. 2817643

  In the conventional aqueous gravure coated paper described above, when gravure printing is performed using water-based ink, the paper is wrinkled due to shrinkage against water, and the paper absorbs water to increase the wet strength. Wood pulp alone could not eliminate the occurrence of paper breakage due to the decline.

  An object of the present invention is to solve such problems of the conventional invention, preventing wrinkles generated on paper due to shrinkage against water, and wetting by absorbing water. An object of the present invention is to provide a coated paper for water-based gravure printing in which paper breakage due to a decrease in strength is prevented and ink acceptance failure is eliminated.

  As a result of intensive studies to solve the above problems, the present invention intends to solve the above problems by the following invention.

That is, in order to achieve the above object, the present invention uses a base paper made of a pulp mixture containing wood pulp and polyolefin-based pulp as a base paper for a water-based gravure printing coated paper. In this case, the polyolefin in the pulp mixture is used. The synthetic synthetic pulp is 20 to 60% by weight, and the particle size is 2.0 μm or less as a pigment component of a coating liquid (hereinafter, abbreviated as “coating liquid”) used for the aqueous gravure-coated paper. There the engineered kaolin is 75% or more and 100 wt% including aqueous gravure coated paper for printing of the pigment component, further, subjected to a calender treatment to the aqueous gravure coated paper for printing, JIS P 8119: According to 1998 The smoothness is 1480 seconds or more . Furthermore, another advantageous solution of the present invention is that the JAPAN TAPPI paper pulp test method no. 27: 2000 "Paper and board - elongation in water Test Method" in elongation in water of Method B by a vertical 0.3% or less, and Ru der those laterally less than 1.0%.

  The effect of the above problem solving means is on a coated paper that is gravure-printed with water-based ink on the surface, and by blending 20 to 60% by weight of synthetic pulp in the total pulp, heat melting with wood pulp Dimensional stability can be improved by the adhesive action of, and the generation of paper wrinkles due to water-based ink can be prevented. In addition, the paper can prevent paper breakage due to a decrease in wet strength by absorbing water. In a further advantageous embodiment, the obtained base paper is coated with engineered kaolin having a particle diameter of 2.0 μm or less as 75% or more as a pigment component and containing 20 to 100% by weight of the pigment component. As a result, surface smoothness is increased, and problems such as acceptability of aqueous gravure printing ink can be solved.

  As described above, the aqueous gravure printing coated paper of the present invention does not excessively beaten, is blended with a polyolefin-based synthetic pulp, and is dimensionally stable, i.e., stretched in water by the adhesive action by heat melting with wood pulp. Since the degree of adhesion is improved and wrinkles are not generated, it is possible to provide a coated paper for water-based gravure printing having no strength and good strength. In addition, by blending 20 to 100% by weight of engineered kaolin in the coating solution, the surface smoothness is increased, the printability with waterborne gravure ink is improved, and waterborne gravure printing has excellent printability. Can provide coated paper.

  The present invention is a water-based gravure-coated paper obtained by providing a coating layer mainly composed of a pigment, an auxiliary agent and an adhesive on a base paper containing synthetic pulp and performing a calendar treatment.

  The polyolefin-based synthetic pulp in the present invention is preferably a polyolefin-based synthetic pulp made of polyethylene or polypropylene having a branched fiber property suitable for a wet papermaking process using a general-purpose paper machine. In particular, those having excellent adhesiveness due to thermal melting with wood pulp due to the drying process during the production of the base paper and the heat history when the coating solution is applied and dried on-machine are preferable for dimensional stability, and the melting point is 100 to 180. Polyolefin synthetic pulp at 0 ° C. is inexpensive and is preferably used. For example, what is marketed under the trade name SWP from Mitsui Chemicals, Inc. can be used, but the present invention is not limited to this SWP.

  The form of these polyolefin synthetic pulps may be short fibers or long fibers as long as they can be made by a paper machine, but the fiber length is preferably in the range of 0.1 to 10 mm. If it is less than 0.1 mm, there is little entanglement between the fibers, and it is difficult to form a sheet substantially. If it exceeds 10 mm, it is difficult to make a uniform sheet by papermaking.

  As the wood pulp used in the present invention, wood bleached chemical pulp typified by N-BKP (conifer bleach bleached kraft pulp) is mainly used. If necessary, mechanical pulp such as L-BKP (hardwood bleached kraft pulp), GP (crushed wood pulp), TMP (thermomechanical pulp), BCTMP (bleached chemithermomechanical pulp), etc., and used paper pulp can be appropriately blended.

  The manufacturing method of the base paper used by this invention uses the pulp mixture which consists of a wood pulp and polyolefin synthetic pulp, and polyolefin synthetic pulp is 20 to 60 weight% in all the pulp, Preferably it is 25 to 55 weight%, Particularly preferably, 28 to 50% by weight is blended. If the polyolefin synthetic pulp compounding ratio is less than 20% by weight, the dimensional stability of the base paper is insufficient, and if the polyolefin synthetic pulp compounding ratio exceeds 60% by weight, the strength is insufficient, which is not preferable as the base paper.

  In the base paper, in addition to the above-mentioned pulp, various yield improvers, paper strength improvers, internal sizing agents, pitch control agents, antifoams are generally used within a range that does not impair the object effects of the present invention. Chemicals such as agents can be used as appropriate.

  The base paper is produced by a general paper machine such as a long net paper machine, a circular net paper machine, a Yankee paper machine, and a long net and circular net combination machine.

  The pigment used in the coating liquid of the present invention is engineered kaolin having a particle size of 2.0 μm or less of 75% or more, 20 to 100% by weight of the total pigment, preferably 50 to 100% by weight, particularly preferably 80 to By blending 100% by weight, especially 100% by weight, a coated paper for aqueous gravure printing having a smooth surface can be obtained. When the blending amount of engineered kaolin having a particle size of 2.0 μm or less of 75% or more is less than 20% by weight, the smoothness of the base paper is lowered and sufficient gravure printing suitability cannot be obtained.

  Latex can be used for the adhesive used in the coating solution of the present invention. The latex is a conjugated diene copolymer latex such as a styrene / butadiene copolymer, a methacrylate / butadiene copolymer, a vinyl polymer latex such as a polymer or copolymer of an acrylate ester and / or a methacrylate ester, Alternatively, these are further modified with a functional group-containing monomer such as a carboxyl group.

  In addition to the dispersant, the auxiliary agent used in the coating solution of the present invention can be appropriately added with a lubricant, an antiseptic, an antifoaming agent, a water resistant agent, a dye, and the like.

  The calendering process of the present invention is performed after forming a coating layer on the base paper, and is performed for the purpose of making the paper thickness uniform, improving the surface smoothness, and improving the glossiness. For calendar processing, machine calendars arranged on-machine, super calendars, friction calendars, gloss calendars, brush calendars, matte calendars, soft calendars, etc. can be used, and the types of calendars are not particularly limited Absent.

  The coating apparatus used for producing the aqueous gravure printing coated paper of the present invention is not particularly limited, and for example, a roll coater, a blade coater, a rod coater, a bar coater, an air knife coater, a gravure coater or the like is used. be able to.

  Regarding the method for producing a water-based gravure printing coated paper of the present invention, the coating liquid may be applied to the base paper off-machine, or the coating liquid may be applied to the base paper on-machine. From. It is preferable to carry out on-machine.

  In the coated paper for aqueous gravure printing of the present invention, JAPAN TAPPI paper pulp test method No. 27: 2000 “Paper and paperboard—in-water elongation test method”, the elongation in water of Method B is preferably 0.3% or less in length and less than 1.0% in width. A material having a height exceeding 0.3% and a width of 1.0% or more is not preferable because of problems such as printing double.

Example:
The present invention will be described in more detail with reference to examples, but the present invention is not limited thereto. In addition, unless otherwise indicated, the part and addition% in an example are a weight part or weight% in conversion of solid content.

<Manufacture of base paper>
L-BKP / N-BKP / SWP (polyethylene synthetic pulp; Mitsui Chemicals, Inc., E620) = 42/18/40% blended pulp was mixed and Canadian standard freeness (hereinafter abbreviated as “freeness”). 450 ml of pulp slurry was obtained, and rosin emulsion (manufactured by Seiko PMC, AL-120) as an internal sizing agent was 0.3% to pulp, sulfuric acid band was 1% to pulp, and cationized starch (manufactured by Nippon Shokuhin Kako). , Neotac 40T) was added to pulp 1%, and paper with a basis weight of 58g / m ² of each layer was made with a round net paper machine to make a paper of 232g / m ² , and with a size press, denaturing polyacrylamide resin (Seiko PMC Co., ST-5000) as a force agent 40 ml / ^{m 2} was coated on both sides at the size press solution of 2.5% solution, dryer After drying, the paper was produced.

<Manufacture of coated paper for aqueous gravure printing>
The coating liquid shown below was applied at 15 g / m ² per one side of the paper with an air knife coater installed in the round net paper machine without applying the size press liquid shown above and winding up the dried base paper. After coating (solid content) and drying, an on-machine calendar process was performed to produce a coated paper for aqueous gravure printing.

<Manufacture of coating liquid>
A dispersant (San Nopco, SN5034) is added to water in an amount of 0.1% with respect to the pigment, and engineered kaolin (Imeris Minerals Japan, Capim NP) (100% by weight of the pigment) as a pigment is 100%. A 68% concentration pigment slurry was prepared with a Cowles disperser. Add additional water to this pigment slurry, put 7.5 parts of SBR latex (Asahi Kasei Co., Ltd., G-1578), 0.2 part of caustic soda and 27% starch solution (manufactured by Nippon Food Processing Co., Ltd., MS-4600). 0.0 part, 1.9 parts of a lubricant (manufactured by San Nopco, NH-237) and 0.1 part of a water retention agent (manufactured by Somar, Somalex 300) were added to obtain a coating solution having a solid content of 63%. .

  The present invention will be described in more detail with reference to examples. In addition, the smoothness, the underwater elongation, and the aqueous gravure printability in the examples were evaluated as follows.

(Smoothness)
The smoothness of the coated surface was measured according to JIS P 8119: 1998 “Paper and paperboard—Smoothness test method using Beck smoothness tester”.

(Underwater elongation)
JAPAN TAPPI Paper Pulp Test Method No. 27: 2000 According to the B method according to “Paper and paperboard—extensibility test in water”, a horizontal test piece having a width of 15 mm and a length of 150 mm was immersed in water at 23 ° C. for 5 minutes using a Fenchel stretch tester. The elongation was expressed in%.

(Suitability for gravure printing)
Printed with water-based ink (Toyo Ink Co., Ltd., Acqua Plus F15) at a printing speed of 60 m / min, printing pressure of 100 kg / cm ² , and blade pressure of 2 kg / cm ^{2 using the} Ministry of Finance Gravure Printing Suitability Tester PM-9004GP. The dot missing rate on the surface of the printed material was counted by counting the number of missing dots in 4557 dots of 10% halftone gravure, and the missing rate was displayed in%.

L-BKP / N-BKP / SWP = 57/18/25% blended pulp was mixed to obtain a pulp slurry having a freeness of 450 ml, and 232 g / m by four-layer papermaking of 58 g / m ² using a round net paper machine. ^A coated paper for aqueous gravure printing was obtained in the same manner as in Example 1 except that paper No. ² was made.

  An aqueous gravure coated coated paper was obtained in the same manner as in Example 1 except that the pulp of the base paper of Example 1 was blended with L-BKP / N-BKP / SWP = 27/18/55%. .

(Comparative Example 1)
A coated paper for aqueous gravure printing was obtained in the same manner as in Example 1 except that L-BKP / N-BKP / SWP = 80/20/0% was blended in Example 1.

(Comparative Example 2)
A coated paper for aqueous gravure printing was obtained in the same manner as in Example 1 except that L-BKP / N-BKP / SWP = 20/10/70% in Example 1.

(Comparative Example 3)
In Example 1, a coating paper for aqueous gravure printing was obtained in the same manner as in Example 1 except that calcium carbonate (TP-123, manufactured by Okutama Kogyo Co., Ltd.) was used instead of engineered kaolin as the coating solution. .

  From the said Table 1, in the pulp which consists of a wood pulp and a synthetic pulp, the usage-amount of the polyolefin-type synthetic pulp in all the pulp is 40 weight% (Example 1), 25 weight% (Example 2), and 55 in all the pulp. In the case of weight% (Example 3), it can be seen that good smoothness, small elongation in water and good gravure suitability are achieved. In contrast, when the amount of polyolefin synthetic pulp used is 0% of the total pulp (Comparative Example 1), it can be seen that the smoothness is poor, the elongation in water is large, and the gravure suitability is remarkably poor. . And when the usage-amount of polyolefin synthetic | combination pulp is 70 weight% (comparative example 2) in all the pulp, it turns out that paper strength is weak and papermaking cannot be performed. Therefore, it can be seen that excellent smoothness, elongation in water, and gravure suitability can be obtained when the amount of polyolefin-based pulp in the total pulp is 20 to 60% by weight.

  From Table 2, engineered kaolin is used as a pigment in Examples 1 to 3 and calcium carbonate is used as a pigment in Comparative Example 3, and excellent smoothness in each example. Although the underwater elongation and gravure suitability were obtained, in the case of Comparative Example 3, with respect to the underwater elongation, only the longitudinal direction was comparable to the example of the present invention, but the lateral direction was too large, and the smoothness and It can be seen that the gravure suitability is remarkably inferior.

Claims (2)

As the base paper for the aqueous gravure printing coated paper, a base paper made of a pulp mixture in which a polyolefin pulp is blended with wood pulp is used, in which the polyolefin synthetic pulp in the pulp mixture is 20 to 60% by weight, and , engineered kaolin 100 wt% including aqueous gravure printing coated paper for pigment components 2.0μm particle size of less than a pigment component coated liquid used in aqueous gravure coated paper for printing is 75% or more Further, the water-based gravure printing coated paper is characterized in that the water-based gravure printing coated paper is calendered to have a smoothness according to JIS P 8119: 1998 of 1480 seconds or more . JAPAN TAPPI PAPER PULSE TEST METHOD NO. The aqueous gravure-coated paper according to claim 1, wherein the elongation in water by 27 is 0.3% or less in length and less than 1.0% in width.