JP6688023B2 - Inkjet recording paper - Google Patents

Description

  The present invention relates to an inkjet recording paper. In particular, the present invention relates to an inkjet recording sheet that can be suitably used as a book sheet.

  The inkjet recording method is a method in which dots are formed by ejecting ink droplets and adhering them onto recording paper to perform recording. In recent years, technological advances in inkjet printers, inks, and recording media have enabled recording with high print quality.

  The inkjet printer technology has been used not only in personal printers used at home, but also in fields such as commercial printing in which variable information is digitized and printed at high speed. That is, in recent years, in the field of commercial printing, a so-called on-demand printing method has been introduced, and many inkjet printers that employ the on-demand printing method have also appeared. The on-demand printing method is suitable for printing a small number of copies because information can be printed directly on a medium such as paper without making a plate.

  In recent years, the on-demand printing method has been adopted also in the field of manufacturing books (texts, comics, literary works, etc.). As the book paper, a paper that is soft and lightweight is used from the viewpoint of ease of turning the paper. The "strain" of paper here is the property that the paper supports its own weight, that is, the resistance when a bending force is applied to the paper. For example, it is also called "stiffness" or "stiffness". is there. As the paper used as the book paper, for example, it is preferable that the paper is hard to stand up when the book is opened. Therefore, the book paper is preferably a low-dough (soft) paper. Ink-jet printers are being introduced even in on-demand printing in the field of book manufacturing. Paper that can be used in this commercial inkjet printer includes coated paper type paper having a coating layer containing an inorganic pigment and non-coated paper type paper having no coating layer containing an inorganic pigment. Although there is paper, it is a non-coated paper that does not have a coating layer containing an inorganic pigment from the viewpoints of ease of turning the paper when used as book paper, lightness, low light reflection, and low eye strain. Engineered paper is often used. On the other hand, as the paper used in the conventional offset printing, coated paper is generally used, but like uncoated paper, it is easy to flip the paper, soft, and has a light feeling of uncoated paper. There is no paper with characteristics. In addition, when printing with an inkjet printing machine on a non-coated paper type book paper used in conventional offset printing, the ink fixability is poor and the ink is bleeding or printing unevenness occurs, which is not practical. There was a problem.

  As a paper suitable for a commercial inkjet printing machine, a printing paper using calcium carbonate having an oil absorption in a specific range in a coating layer of the inkjet recording paper in order to improve the ink absorbability (for example, Patent Document 1). However, it is a coated paper type paper, and it is easy to flip the paper like conventional non-coated paper type book paper, has a soft texture and is lightweight. Cannot be provided, and it is difficult to suitably use it as a book paper. In addition, as a so-called non-coated paper type paper, an inkjet paper (for example, see Patent Document 2) in which the type of starch, which is a paper strength agent, is limited to improve the ink absorbability has been proposed. It is hard and heavy, and it is difficult to use it as a book paper. Therefore, there is no optimum inkjet paper that is compatible with commercial inkjet printers and has a soft and light weight like conventional book papers.

JP, 2008-238612, A JP, 11-334199, A

  Therefore, an object of the present invention is to have a soft and light feeling, has a texture similar to uncoated paper having no coating layer containing an inorganic pigment, and has good ink fixability, and ink Another object of the present invention is to provide an inkjet recording paper that is less likely to cause blurring of printing and uneven printing. That is, although it is a non-coated paper type, it has good ink jet recording suitability for a commercial high speed ink jet printing machine (for example, a printing machine having a printing speed of more than 50 m / min), and a book paper. An inkjet recording sheet that can be suitably used as the above is provided.

The ink jet recording paper according to the present invention is a non-coated paper type ink jet recording paper having no coating layer containing an inorganic pigment, containing an ink fixing agent, a bulking agent and a cationic sizing agent. The fixing agent is a cationic polymer, and is an inkjet recording paper having a specific volume (specific volume) of 1.25 to 2.00 cm ³ / g.

The inkjet recording paper according to the present invention preferably has a basis weight of 50 to 100 g / m ² from the viewpoint of the lightweight feeling of the paper and the stiffness.

  According to the present invention, it is possible to provide an ink jet recording sheet having good ink jet recording suitability, having a soft feeling and light weight, and having no coating layer containing an inorganic pigment. Further, the inkjet paper according to the present invention is suitable for being used as a book paper, and can be applied to a commercial inkjet printing machine.

  Next, the present invention will be described in detail by showing embodiments, but the present invention is not construed as being limited to these descriptions. The embodiments may be variously modified as long as the effects of the present invention are exhibited.

  The inkjet recording book paper of the present invention contains pulp as a main component. Examples of the pulp used here include chemical pulp such as LBKP (hardwood bleached kraft pulp) and NBKP (softwood bleached kraft pulp), GP (groundwood pulp), PGW (pressurized groundwood pulp), RMP (refiner mechanical pulp), Mechanical pulp such as TMP (thermo-mechanical pulp), CTMP (chemi-thermo-mechanical pulp), CMP (chemi-mechanical pulp) and CGP (chemi-ground pulp), wood pulp such as DIP (deinking pulp) and kenaf, bagasse, bamboo, Non-wood pulp such as cotton. These can be used alone or mixed in any proportion. For example, it is preferable that LBKP is mainly contained and LBKP is contained in an amount of 80 to 100% by mass with respect to the total mass of pulp. Among these, it is also preferable that the main component is chemical pulp from the viewpoint of suitability for inkjet recording. Furthermore, it is desirable to mix ECF (Elemental Chlorine Free) pulp or TCF (Totally Chlorine Free) pulp with a low environmental load. Further, the pulp constituting the base paper according to the present invention is preferably a stock having an appropriate beating degree as an inkjet printing paper. An appropriate beating degree is, for example, a Canadian standard freeness (freeness) (JIS P 8121: 1995 “Pulp freeness test method”) and 350 to 650 ml CSF. In the paper, known fillers such as heavy calcium carbonate, light calcium carbonate, magnesium carbonate, titanium oxide, synthetic silica, alumina, talc, calcined kaolin clay, kaolin clay, bentonite, zeolite, aluminum hydroxide, zinc oxide, etc. Well-known paper-strengthening agents, sulfuric acid bands, retention aids, dyes, fluorescent dyes, and other various paper-making chemicals may be appropriately used. In the present invention, light calcium carbonate is preferable as the filler from the viewpoints of bulkiness and prevention of ink bleeding. The preferable amount of light calcium carbonate added is such that the ash content of the paper after papermaking is 10 to 30% by mass. More preferably, it is 12 to 28%. The preparation method of each stock, the mixing method, and the addition method of each paper-making chemical are not particularly limited as long as the effects of the present invention are not impaired. Further, it is possible to make paper by using a known paper machine such as a cylinder paper machine, a fourdrinier paper machine, a twin wire paper machine, etc. using a paper material, and either single-layer papermaking or multi-layer papermaking may be used. . Further, it is also possible to mix waste paper pulp as pulp as long as the effect of the present invention is not impaired. Further, a known water-soluble polymer such as starch, polyvinyl alcohol, polyacrylamide, etc. can be applied with a size press or a gate roll coater.

  In the present invention, it is essential that the paper contains a cationic polymer as an ink fixing agent, a bulking agent, and a cationic sizing agent. As a method of containing it in the paper, it may be added to the stock, or may be added to a size press liquid or a gate roll coater coating liquid applied by a size press or a gate roll coater, and the bulking agent is It is good to add it to the stock. This is because the specific volume can be adjusted appropriately. Further, the cationic polymer and the cationic sizing agent may be added to the size press liquid or the gate roll coater coating liquid. This is because the optimum ink fixability can be obtained. Further, the cationic sizing agent and the cationic polymer can be added together to the solution to be applied with a size press or a gate roll coater. For example, the cationic polymer and the cationic sizing agent can be added to a size press liquid containing 2 to 7% by mass of oxidized starch. This is because the cationic sizing agent has good compatibility with the cationic polymer and thus has the effect of improving the stability of the solution applied by a size press or a gate roll coater.

Examples of the bulking agent used in the present invention include ester compounds of higher alcohols or polyhydric alcohols and fatty acids, polyoxyalkylene adducts of ester compounds of polyhydric alcohols and fatty acids, fatty acid polyamide amines, and saturated fatty acid polyamide polyamines epichloro. Known bulking agents such as hydrin reaction products, higher alcohol ethylene oxide adducts, higher alcohol propylene oxide adducts, higher alcohol or higher fatty acid polyoxyalkylene adducts, higher fatty acid ester polyoxyalkylene adducts, etc. It is possible to use. These may be used alone or in combination of two or more. In the present embodiment, the bulking agent is preferably contained in an amount of 0.01 to 2.0 parts by mass with respect to 100 parts by mass of pulp. When the content of the bulking agent is less than 0.01 parts by mass, the bulkiness effect cannot be satisfactorily obtained, and the specific volume of the inkjet paper becomes low. If it exceeds 2.0 parts by mass, the bulkiness effect is obtained, but the strength of the paper layer is lowered and the paper is easily broken. More preferably, the bulking agent is contained in an amount of 0.05 to 1.5 parts by mass with respect to 100 parts by mass of pulp. Further, in the present invention, it is necessary to adjust the specific volume of the inkjet recording paper to 1.25 to 2.00 cm ³ / g by adding the bulking agent. If the specific volume is less than 1.25 cm ³ / g, it will be stiff and unsuitable for book paper, and if the specific volume exceeds 2.00 cm ³ / g, there will be too many voids in the paper and ink jet The unevenness of the solid portion at the time of printing increases, and the strength of the paper layer decreases, and the paper is easily torn. In the present invention, the specific volume of the inkjet recording paper is preferably 1.30 to 1.95 cm ³ / g. The specific volume (cm ³ / g) referred to in the present invention is a value obtained by dividing the thickness (μm) of the inkjet recording paper by the basis weight (g / m ² ).

In the present invention, the inkjet recording paper contains a cationic sizing agent. The inkjet recording paper of the present invention does not have a coating layer having an inorganic pigment, has a relatively high specific volume, and may contain a bulking agent, so that the ink easily penetrates into the paper when printed by the inkjet recording method. Has become. However, by incorporating the cationic sizing agent, it is possible to prevent the ink from seeping into the paper. As the cationic sizing agent used here, known sizing agents such as alkyl ketene dimer (AKD), alkenyl succinic anhydride (ASA), styrene-acryl copolymer, styrene-methacryl copolymer, rosin sizing agent, etc. It is preferable that the ionic property is cationic. These may be used alone or in combination of two or more. Since the ink is anionic, by containing a cationic sizing agent, it is possible to suppress ink bleeding and printing unevenness by suppressing ink bleeding into the paper while improving ink fixability moderately. It will be possible. In the present invention, the content of the cationic sizing agent in the paper is preferably 0.001 to 0.1 g / m ² , and more preferably 0.005 to 0.05 g / m ² . When the content of the cationic sizing agent is less than 0.001 g / m ² , it is not possible to sufficiently prevent the ink from seeping into the paper, and the ink may become bleed. If it exceeds 0.1 g / m ² , ink penetration into the paper is excessively suppressed, and uneven printing is likely to occur. In addition, a nonionic sizing agent and an anionic sizing agent can be used in combination as long as the effects of the present invention are not impaired.

Further, in the present invention, the inkjet recording paper further contains a cationic polymer as an ink fixing agent. By combining a cationic polymer and a cationic sizing agent, ink bleeding and printing unevenness can be prevented even though it is an inkjet recording paper that contains a bulking agent and has a high specific volume and does not have a coating layer. Further, it can be suppressed. As described above, in the ink jet recording paper of the present invention, the cationic sizing agent is contained so that the ink fixability is improved while suppressing the ink from seeping into the paper. However, the ink jet recording paper of the present invention, which is a so-called non-coated paper having no coating layer having an inorganic pigment, further contains a bulking agent and has a relatively high specific volume. Satisfactory inkjet recording suitability cannot be obtained only by adding a functional sizing agent. Specifically, it is not possible to satisfactorily suppress ink bleeding and printing unevenness. Therefore, in the present invention, the inkjet recording paper further contains a cationic polymer as an ink fixing agent. Examples of the cationic polymer used as the ink fixing agent in the present invention include polyethyleneimine, epichlorohydrin-modified polyalkylamine, polyamine, polyamine polyamide epichlorohydrin, dimethylamine ammonia epichlorohydrin, polyvinylbenzyltrimethylammonium halide, polydiacryldimethylammonium halide. , Polydimethylaminoethyl methacrylate hydrochloride, polyvinylpyridium halide, cationic polyacrylamide, cationic polystyrene copolymer, diallyldimethylammonium chloride polymer, diallyldimethylammonium chloride sulfur dioxide copolymer, diallyldimethylammonium chloride amide copolymer , Dicyandiamide formalin polycondensate, dicyandia Dodiethylenetriamine polycondensate, polyallylamine, polydiallylamine, polyallylamine hydrochloride, polyacrylamide resin, polyamide epoxy resin, melamine resin acid colloid, urea resin, cation-modified polyvinyl alcohol, amino acid amphoteric surfactant, betaine compound , Polyamidine compounds, other quaternary ammonium salts, and cation-modified polyurethane resins. These may be used alone or in combination of two or more. In the present embodiment, the content into the paper of the cationic polymer is preferably 0.1 to 5.0 g / ^{m 2,} more preferably at 0.2~4.0g / ^{m 2} . When the content of the cationic polymer is less than 0.1 g / m ² , the ink easily bleeds, and when it exceeds 5.0 g / m ² , uneven printing is likely to occur.

The inkjet paper according to the present invention preferably has a grammage of 50 to 100 g / m ² from the viewpoint of lightness and stiffness. More preferably, it is 60 to 90 g / m ² . When the basis weight is less than 50 g / m ² , strikethrough or show-through occurs after inkjet printing, and when it exceeds 100 g / m ² , the feeling of lightness is poor.

  In the production method of the present invention, pulp and a bulking agent, for example, a stock containing 0.01 to 2.0 parts by mass of fatty acid polyamidoamine per 100 parts by mass of pulp is used in a Fourdrinier paper machine. It is preferable that after papermaking and obtaining a web, the aqueous solution containing the cationic polymer and the cationic sizing agent is applied to the web and then dried. In the present invention, it is also possible to carry out a smoothing process by performing a calendar process such as a machine calendar, a soft calendar or a super calendar.

  Next, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples. Further, “parts” and “%” in the examples represent “parts by mass” and “mass%”, respectively, unless otherwise specified. The number of parts added is a value in terms of solid content.

( Reference example 1)
To 100 parts of hardwood bleached kraft pulp (Canadian standard freeness 490 ml CSF), 0.3 parts of starch (NeoTack 30T: manufactured by Nippon Food Processing Co.), 0.2 parts of nonionic rosin sizing agent (CC167: Seikou PMC) Light calcium carbonate (PC-700: manufactured by Shiraishi Industry Co., Ltd.) whose amount added is adjusted so that the ash content of the paper after papermaking is 15%, and fatty acid polyamidoamine as a bulking agent (Mask-K300: manufactured by Nika Chemical Co., Ltd.) 0.5 parts and were mixed to obtain a paper stock. Papermaking was carried out using a Fourdrinier paper machine using this stock material (single-layer papermaking). Then, as a size press liquid, 5% of oxidized starch (MS # 3800: manufactured by Nippon Shokubai Co., Ltd.), 3% of a cationic polymer polyamine resin (DK6810: manufactured by Seikou PMC) as an ink fixing agent, and a cationic An aqueous solution prepared by mixing 0.05% of a styrene-acrylic copolymer (Harsize CP-960E: manufactured by Harima Kasei Co., Ltd.), which is a sizing agent, was applied to both sides of the paper web at a dry coating amount of 2.0 g / m per side. ^It was applied by a size press so as to be ^2, and dried by a cylinder dryer to prepare an inkjet recording paper having a basis weight of 60 g / m ² and a thickness of 90 μm (specific volume 1.50 cm ³ / g).

( Reference example 2)
An inkjet recording paper was produced in the same manner as in Reference Example 1 except that the amount of the bulking agent fatty acid polyamidoamine (Muskut K300: manufactured by Nichika Chemical Co., Ltd.) was changed to 0.05 parts by mass. The basis weight of the obtained paper was 60 g / m ² , and the thickness was 76 μm (specific volume 1.27 cm ³ / g).

( Reference example 3)
An ink jet recording paper was prepared in the same manner as in Reference Example 1 except that the amount of the bulking agent fatty acid polyamidoamine (Maskuto K300: manufactured by Nichika Chemical Co., Ltd.) was changed to 2.0 parts by mass. The basis weight of the obtained paper was 60 g / m ² , and the thickness was 120 μm (specific volume 2.00 cm ³ / g).

( Reference example 4)
In Reference Example 1, the cationic sizing agent to be added to the size press liquid is a styrene-acrylic copolymer (Harsize CP-960E: manufactured by Harima Kasei) and a cationic alkyl ketene dimer (SE2360: manufactured by Seikou PMC). An inkjet recording paper was produced in the same manner as in Reference Example 1 except that The basis weight of the obtained paper was 60 g / m ² , and the thickness was 90 μm (specific volume 1.50 cm ³ / g).

(Example 5)
In Reference Example 1, a cationic polymer as an ink fixing agent to be added to the size press liquid was prepared from polyamine resin (DK6810: manufactured by Seikou PMC) and diallyldimethylammonium chloride polymer (Unisense CP-103: manufactured by Senka). An inkjet recording paper was produced in the same manner as in Reference Example 1 except that The basis weight of the obtained paper was 60 g / m ² , and the thickness was 90 μm (specific volume 1.50 cm ³ / g).

(Example 6)
In Reference Example 1, the cationic polymer as an ink fixing agent added to the size press liquid was changed from a polyamine resin (DK6810: manufactured by Seikou PMC) to a cationic polyamidine resin (SC-700L: manufactured by Hymo). An inkjet recording paper was produced in the same manner as in Reference Example 1 except for the above. The basis weight of the obtained paper was 60 g / m ² , and the thickness was 90 μm (specific volume 1.50 cm ³ / g).

( Reference example 7)
An inkjet recording paper was produced in the same manner as in Reference Example 1 except that the basis weight of the paper was adjusted to 80 g / m ² . The basis weight of the obtained paper was 80 g / m ² , and the thickness was 120 μm (specific volume 1.50 cm ³ / g).

(Reference example 8)
An inkjet recording paper was produced in the same manner as in Reference Example 1 except that the basis weight of the paper was adjusted to 100 g / m ² . The obtained paper had a basis weight of 100 g / m ² and a thickness of 150 μm (specific volume 1.50 cm ³ / g).

( Reference example 9)
An inkjet recording paper was produced in the same manner as in Reference Example 1 except that the amount of the bulking agent fatty acid polyamidoamine (Muskut K300: manufactured by Nichika Chemical Co., Ltd.) was changed to 1.0 part by mass. The basis weight of the obtained paper was 60 g / m ² , and the thickness was 117 μm (specific volume 1.95 cm ³ / g).

(Example 10)
Reference Example 1, the cationic polymer as an ink fixing agent added to the size press liquor, dicyandiamide polycondensates: was changed to (Parakon PJ-O Ohara manufactured palladium Co.) in the same manner as in Reference Example 1 inkjet A recording paper was prepared. The basis weight of the obtained paper was 60 g / m ² , and the thickness was 90 μm (specific volume 1.50 cm ³ / g).

( Reference example 11)
In the same manner as in Reference Example 1, except that the cationic polymer as the ink fixing agent added to the size press liquid was changed to dimethylamine ammonia epichlorohydrin polycondensate (Papiogen P-103: manufactured by Senka Co.). Thus, an inkjet recording paper was prepared. The basis weight of the obtained paper was 60 g / m ² , and the thickness was 90 μm (specific volume 1.50 cm ³ / g).

(Comparative Example 1)
Reference Example 1, the size styrene cationic sizing agent to press liquor - acrylic copolymer: except for not adding the (hard size CP-960E Harima Kasei Co., Ltd.) is the same manner as in Reference Example 1, an ink jet recording Paper was made. The basis weight of the obtained paper was 60 g / m ² , and the thickness was 90 μm (specific volume 1.50 cm ³ / g).

(Comparative example 2)
An inkjet recording paper was prepared in the same manner as in Reference Example 1 except that the cationic polymer polyamine resin (DK6810: manufactured by Seikou PMC) was not added to the size press liquid as an ink fixing agent. did. The basis weight of the obtained paper was 60 g / m ² , and the thickness was 90 μm (specific volume 1.50 cm ³ / g).

(Comparative example 3)
In Reference Example 1, a styrene-acrylic copolymer which is a cationic sizing agent (Harsize CP-960E: manufactured by Harima Kasei Co., Ltd.), which is a cationic sizing agent, is added to the size press liquid, and a styrene-acrylic copolymer which is an anionic sizing agent. An inkjet recording paper was prepared in the same manner as in Reference Example 1 except that the product (Polymaron 1308S: manufactured by Arakawa Chemical Industry Co., Ltd.) was used. The basis weight of the obtained paper was 60 g / m ² , and the thickness was 90 μm (specific volume 1.50 cm ³ / g).

The following evaluation was performed on the obtained inkjet recording paper, and the results are shown in Table 1. Further, the specific volume (cm ³ / g) referred to in the present invention is a value obtained by dividing the thickness (μm) of the inkjet recording paper by the basis weight (g / m ² ).

(1) Character blurring:
Using a commercial inkjet printer (HP T300 Color InkjetPress: manufactured by Hewlett Packard), characters were printed on the obtained inkjet recording paper with black, cyan, magenta and yellow at a printing speed of 120 m / min. The degree of bleeding of the printed characters was visually determined and evaluated according to the following four grades.
⊚: Characters do not bleed at all and can be used practically.
◯: Characters are slightly blurred, but practical.
Δ: Characters are blurred and not practical.
X: Practically impractical because the characters are markedly blurred.

(2) Solid area unevenness:
Using a commercial inkjet printer (HP T300 Color InkjetPress: manufactured by Hewlett Packard), solid images were printed on the obtained inkjet recording paper with black, cyan, magenta and yellow at a printing speed of 120 m / min. The unevenness of the printed solid portion was visually determined and evaluated according to the following four grades.
⊚: There is no unevenness and it can be used practically.
◯: Practical use with slight unevenness.
Δ: There is unevenness and it is not practical.
Poor: Practical use is not possible due to remarkable unevenness.

As is clear from Table 1, the inkjet recording papers obtained in Examples 5 , 6 and 10 and Reference Examples 1 to 4 , 7 to 9 and 11 were excellent in inkjet recording suitability. Further, any of the inkjet recording papers was easy to turn over, had a soft texture, and had a light weight feeling, and was suitable for being used as a book paper.

  On the other hand, the ink jet recording paper obtained in Comparative Example 1 did not contain a cationic sizing agent, so the ink bleeded and the solid portion was uneven. Further, the ink jet paper obtained in Comparative Example 2 did not contain a cationic polymer, so that the ink remarkably bleeded and the solid portion was remarkably uneven. Since the ink jet recording paper obtained in Comparative Example 3 used the anionic sizing agent instead of the cationic sizing agent, the ink bleeded and unevenness was generated in the solid portion.

Claims (5)

An ink jet recording paper as a book paper having no coating layer containing an inorganic pigment, comprising an ink fixing agent, a bulking agent which is a fatty acid polyamidoamine, and an alkyl ketene dimer (AKD) or a styrene-acrylic copolymer. contain certain cationic sizing agent, an ink fixing agent is cationic polymer, wherein the cationic polymer is diallyldimethylammonium chloride polymer, polyamidine compound, or a polycondensate of dicyandiamide, specific volume Is 1.25 to 2.00 cm ³ / g, and the basis weight is 50 to 80 g / m ² . Basis weight 50~60g / m are ^two der, ink-jet recording sheet according to claim 1, wherein the ink-jet recording sheet is high commercial ink jet recording paper exceeding the printing speed 50 m / min. Ink fixing agent, the ink jet recording sheet according to claim 1 or 2, characterized in that diallyldimethylammonium chloride polymers or polyamidine compound.   The inkjet recording paper according to claim 1, wherein the cationic sizing agent is a styrene-acrylic copolymer.   It is a manufacturing method of the inkjet recording paper as a book paper as described in any one of Claims 1-4, Comprising: Pulp, and fatty acid polyamidoamine as a bulking agent are 0.01-100 mass parts of pulp. Inkjet, characterized in that 2.0 parts by mass of paper stock is made into paper, a web is obtained, an aqueous solution containing a cationic polymer and a cationic sizing agent is applied to the web, and then dried. Recording paper manufacturing method.