JP2003103914A - Ink jet recording glossy paper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide ink jet recording glossy paper which can have a recording image of high quality particularly with an ink jet dye ink, by a casting method having an excellent gloss quality. SOLUTION: The ink jet recording glossy paper comprises a coating liquid containing a pigment and a binding agent and coating on at least one surface of original paper in such a manner that the coating surface is solidified by a coagulant and the coating layer is cast processed while the coating surface remains in a wet state and the solidifying liquid contains a cationic polyallylamine condensed derivative of a pH of 8 or higher having primary and secondary ammonium salts within a molecule.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cast glossy paper for inkjet recording, and more particularly to a recording paper having a high printing surface gloss and excellent inkjet recording characteristics.

[0002]

2. Description of the Related Art The ink jet recording system is a system in which ink droplets are ejected and deposited on recording paper to form dots for recording. In recent years, technical improvements in inkjet printers, inks, and recording media have enabled recording with high print quality.

Recently, as the performance of ink jet recording type printers using water-based ink has been improved, characteristic requirements such as high absorbency, faithful dot reproducibility, and water resistance have been demanded even on recording paper. As a result, coated paper having an ink receiving layer provided on a support has been developed.

In addition to the high performance of ink jet printers, along with the expansion and popularization of peripheral devices such as digital cameras and scanners, ink jet recording paper as a recording medium is required to have further improved performance. Is coming. In other words, at present, with widespread applications such as high-speed inkjet recording, high-definition recording images, and full-color recording, inkjet recording papers with high surface gloss and excellent appearance are required in addition to good inkjet printing suitability. Is coming. Requirement items that can be added to it include gloss, hue, and texture, and it may be kept in mind that it is similar to photographic printing paper or printing paper for silver halide photography.

Generally, as a paper having a high surface gloss,
After coating a hollow plastic pigment or a plate-shaped or fine particle inorganic pigment, the coated paper surface is processed by a calender process to obtain a coated paper with high smoothness and excellent absorbency. Cast coated paper obtained by copying a mirror surface of a coated paper of a type coated with a synthetic resin having film-forming properties or a wet coating layer by pressing and drying it on a heating drum surface having a mirror surface. It has been known.

[0006] This cast coated paper has a higher surface gloss and smoothness than ordinary coated paper such as super calender whose surface has been smoothed, and has excellent printability. For many reasons, it is often used as a high-grade printing paper among printed materials. However, there are some disadvantages when the cast coated paper is used as an inkjet recording paper.

Some of the disadvantages are listed. First, in the case of cast coated paper, gloss is usually expressed by transferring the mirror surface of the drum, but in order to obtain high gloss, the presence of film-forming substances such as casein, polyvinyl alcohol, and urethane is essential. And, it must be used in large quantities. However, these film-forming substances impede the absorption of the inkjet ink into the coated paper, and as a result, they may become a factor that the printed surface bleeds or the drying property of the ink is significantly deteriorated. On the contrary, if the amount of the film-forming substance used is reduced, the ink absorbability is improved, but the gloss value is lowered.

Further, the pigments and binders used in cast paints are mainly nonionic or anionic ones. With this composition, the ink jet ink cannot be sufficiently fixed. However, it causes poor water resistance of the recorded image area and a decrease in print density.

In order to improve the water resistance of the ink jet recording paper and decrease the printing density, it is possible to improve the ink fixability by introducing an organic cation agent into the coating layer. However, in the cast coating liquid, the cationic substance is poorly compatible with the anionic release agent, the alkali-modified binder, and the like, and may cause thickening or aggregation. As described above, in applying the cationic substance to the cast coated paper, it is necessary to select appropriate conditions such as the kind of the cation, the addition amount, or the order of addition during preparation of the solution.

There are many reports of using an organic cationic agent such as a cationic polymer as a coagulant for a cast coating liquid, but the characteristic feature is that the use thereof imparts water resistance. Further, as a problem, there is a tendency that due to an excessively large amount thereof, ink absorbency is deteriorated and storage stability such as light resistance is deteriorated. further,
Although there is a cationic substance having a pH that is too low, the storage stability of recorded images may deteriorate. Depending on the type of the cationic polymer, the original color development of the ink may be impaired, or it may react with other substances at the time of preparing the coating liquid to cause aggregation or the formation of precipitates. Also,
Even if the preparation is good, the storage stability of the coating solution may deteriorate over time. The use of such a coating liquid makes it difficult to form a uniform glossy surface.

As described above, when the organic cationic agent is used as the coagulating liquid, in addition to the degree of gelation of the cast coating liquid, the printing density and color tone of the recorded image portion, and further the recording image portion such as water resistance and light fastness. It is necessary to decide the type and amount of the liquid used, taking into consideration the storage stability, the liquid preparation property, and the stability of the coating liquid. Generally, the gelling strength of the organic cation agent is weaker than that of the metal salt which is an inorganic substance. In addition, there are a wide variety of organic cation agents, among which there are excellent ink fixability and particularly good water resistance,
Some of them have poor water resistance, but also have excellent color development and light resistance of the ink. Therefore, it is necessary to select an organic cation agent so as to obtain a well-balanced printing quality for these requirements.

[0012]

The present invention has high quality recorded images, especially for inkjet dye inks,
In addition, we provide inkjet glossy paper by the casting method that excels in gloss quality.

[0013]

According to the present invention, a pigment and a coating liquid containing an aqueous binder are dissolved on at least one surface of a base paper, and then a coagulating liquid in which a coagulant is dissolved is used.
A cast coated paper obtained by pressure-bonding a coating layer to a heated mirror-finished metal surface while the coating layer is in a wet state after being coagulated, and has a pH of 8 or more in a coagulating liquid. Particularly preferred is a glossy paper for ink-jet recording, characterized by containing 10 or more and a cationic polyallylamine condensed derivative having primary and secondary ammonium salts in the molecule. 1 in the molecule used in the present invention
The cationic polyallylamine condensed derivative having a primary and secondary ammonium salt is a polycondensed derivative of an allyl compound in which one or more primary and secondary ammonium bases are added to a chain having a condensed skeleton of an allyl compound as a basic skeleton, respectively. It is a cationic polyallylamine condensed derivative having a methyl group as a substituent. In the present invention, it is advantageous to use borax as the coagulating substance of the gloss coating liquid. Even when borax is used together, the pH of the coagulant is 8 or more, preferably 10 or more.

The details of the present invention will be described below. The glossy paper of the present invention is produced by a known cast coating method using paper as a base material. The cast coating method can be classified into a wet method, a rewet method, and a coagulation method depending on the method of forming a glossy surface, and the method in the present invention is the coagulation method.

In this method, it is important to select the coagulant and the amount of the coagulant corresponding to the binder used in the gloss developing layer. As a coagulant, calcium salts such as formic acid, acetic acid, citric acid, tartaric acid, lactic acid, hydrochloric acid and sulfuric acid, salts such as zinc, barium, lead, magnesium, cadmium and aluminum, potassium sulfate, potassium citrate, borax and boric acid can be used. However, in the case of polyvinyl alcohol and polyvinyl acetal, a combination of boric acid or borax is preferable. The amount of the coagulant is preferably 5% by weight or more based on the resin component in the printing surface coating layer. If it is less than 5% by weight, a sufficiently glossy surface cannot be obtained.

The coagulating liquid contains an organic cationic agent and a coagulating agent. Here, the organic cation agent has a role of imparting ink fixability, but is a cationic polyallylamine condensed derivative having primary and secondary ammonium salts in the molecule, or polyethyleneimine, epichlorohydrin-modified polyalkylamine, polyvinylbenzyltrimethylammonium halide. , Polydiacryldimethylammonium halide, polydimethylaminoethylmethacrylate hydrochloride,
There are polyvinylpyridinium halides, other quaternary ammonium salts, polyamines and the like.

Although the concentration of the organic cation agent in the coagulant solution depends on the concentration of borax used together and the coating amount of the gloss-developing layer, the weight concentration of the organic cation agent depends on the quality of the coated paper, storage stability, and The following conditions are mentioned as a range which does not hinder suitability for cast coating. That is, 0.1 to 5.
It is 0% by weight, and more preferably 0.3 to 2.0% by weight.

The coating material forming the coating layer of the present invention contains a pigment, a binder and a release agent, and if necessary, an ink fixing agent. The pigment used in the present invention is, as an inorganic pigment, light calcium carbonate, magnesium carbonate, kaolin, barium sulfate, aluminum silicate, magnesium silicate, synthetic amorphous silica, colloidal silica, alumina, colloidal alumina, a composite of alumina and silica, zeolite. White pigments such as diatomaceous earth and magnesium hydroxide can be used. In the present invention, the glossy surface quality and the printing quality are good,
Alumina or a composite of alumina and silica is preferred. The particle diameter of the inorganic pigment is at most 1 μm or less, preferably 0.01 to 0.5 μm. If it exceeds 1 μm, the ink absorbability is good, but it becomes difficult to obtain gloss,
When it is less than 0.01 μm, gloss is easily obtained, but ink absorbability may be poor. It is also possible to add an organic pigment in combination with the inorganic pigment.

When an ink receiving layer provided below the gloss developing layer is provided, the pigment applicable to this layer is
From light calcium carbonate, magnesium carbonate, kaolin, barium sulfate, aluminum silicate, magnesium silicate, synthetic amorphous silica, colloidal silica, alumina, colloidal alumina, composite of alumina and silica, zeolite, diatomaceous earth, magnesium hydroxide, etc. It is preferable to choose.

The binder used in the coating layer in the present invention is polyvinyl alcohol, polyvinyl acetal,
Oxidized starch, etherified starch, carboxymethyl cellulose, hydroxyethyl cellulose, casein, gelatin, soybean protein, polyethylene imide resin, polyvinyl pyrohydrin resin, polyacrylic acid or its copolymer, maleic anhydride copolymer, acrylamide Resin, acrylic ester resin, polyamide resin, polyurethane resin, polyester resin, polyvinyl butyral resin, alkyd resin, epoxy resin,
Epichlorohydrin resin, urea resin, melamine resin,
Acrylic polymer latexes such as styrene-butadiene copolymer, methyl methacrylate-butadiene copolymer, acrylic acid ester, methacrylic acid ester polymer or copolymer, vinyl-based polymer such as ethylene-vinyl acetate copolymer Resins of the combined latex are exemplified, and they are used alone or in combination. Particularly preferred binders are polyvinyl alcohol and polyvinyl acetal, which are used alone or in combination with the above resins. When polyvinyl alcohol and polyvinyl acetal are used as binders, the use of boric acid or borax as a coagulant is effective for smoothing the surface of the gloss developing layer, as described above. The amount of binder used is
It is determined in consideration of the printability of the recording medium, the strength of the ink receiving layer, and the coating liquid property. Usually, it is added in the range of 1 to 200 parts by weight, preferably 5 to 100 parts by weight, based on the weight of the pigment.

In the present invention, the addition of the cationic polyelectrolyte reacts with the anion component in the dye used in the ink to form a salt insoluble in water. improves. Examples of such a cationic polyelectrolyte include polyethyleneimine, epichlorohydrin-modified polyalkylamine, polyvinylbenzyltrimethylammonium halide, polydiacryldimethylammonium halide, polydimethylaminoethylmethacrylate hydrochloride, polyvinylpyridinium halide, and other quaternary ammonium salts. And polyamines are used. The cationic polyelectrolyte can be added to the coating liquid or the coagulating liquid constituting the ink receiving layer.
The amount of addition is 1 to 50% by weight based on the total weight of the binder. A particularly preferable addition range is 5 to 30% by weight.

Commonly used mold release agents are polyethylene wax, stearic acid amide, calcium stearate, ammonium oleate, oleic acid amide, potassium oleate, paraffin wax, alkyl ketene dimer, higher alcohol and nonion. Specific examples include a surface active agent.

As other additives, a defoaming agent, a lubricant, a dispersant, a wetting agent and the like can be used if necessary.

The coating method for coating the coating layer of the present invention includes air knife, roll coater, bar coater,
Known coating machines such as a comma coater and a blade coater are used. The coating amount is 5 to 40 g / m ^{2 in} terms of solid content,
The range of 7 to 30 g / m ² is preferable. If the coating amount exceeds 40 g / m ² , there is an economic disadvantage and there is concern that the surface strength of the coated paper may deteriorate. On the contrary, the coating amount is 5g
If it is less than / m ² , it is difficult to form a sufficiently glossy surface.

The glossy surface in the present invention is formed by coating the coating material with the above coater, applying a coagulating liquid to the coated surface to solidify the coating material, and pressing the surface onto a cast drum. This step is an important step when forming a coating layer having a high gloss surface quality and high ink absorption performance in the glossy paper of the present invention.

The coagulant to be used is as described above. In addition, the time until the coagulant is applied to reach the cast drum, the temperature of the cast drum, the pressure at the time of pressure bonding, and the line speed are adjusted. An ink receiving layer surface with less surface cracks can be formed. It is necessary to optimize these various conditions by finding the optimum conditions according to the equipment and paint used.

As the base material used in the present invention, a paper base material such as ordinary high-quality paper, medium-quality paper, and white paperboard is used. Considering the case of recycling as fuel, it is desirable to use ECF pulp or TCF pulp with a low chlorine content as the raw material pulp. In order to prevent excessive penetration of the paint during cast coating, it is preferable to use a base paper coated with a water-soluble polymer such as starch or polyvinyl alcohol by a size press.

Further, as described above, it is also possible to provide an undercoat layer composed of a pigment and an adhesive on the substrate, and to provide the cast coat layer of the present invention on this.

[0029]

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. Further, “parts” and “%” shown in the examples represent solid parts by weight and solid weight% unless otherwise specified.

<Contents of Support> The base paper as the support has the following specifications. Mitsubo: 127 g / m ² , paper thickness: 130 μm,
It has a Bekk smoothness of 50 seconds and an air permeability of 18 seconds, and is made of wood pulp.

<Coating of ink receiving layer> An ink receiving layer was obtained by coating a coating composition having a porous inorganic pigment and a binder as main components on the support. The coating composition is a commercially available synthetic amorphous silica (Cyloid P as a porous inorganic pigment).
407: 100 parts of Grace Co., particle size 7 μm, commercially available polyvinyl alcohol (PVA-) as a binder
It was obtained by mixing 10 parts of 117K: manufactured by Kuraray Co., Ltd. and 40 parts of ethylene vinyl acetate (EVA AD-6K: manufactured by Showa High Polymer Co., Ltd.). The solid content concentration of the coating composition is 15%.
The coating composition was dried with an air knife coater to an absolute dry weight of 5 g /
It was coated on a support so as to have m ^2, and then dried by an air dryer to obtain an ink receiving layer.

Example 1 <Preparation of gloss layer coating liquid> As a pigment, 100 parts of a composite of alumina and silica (VP DOP 3375: manufactured by Nippon Aerosil Co., Ltd., particle size: 50 nm), and polyvinyl alcohol (PVA-235: as a binder: PVA-235: 5 parts (manufactured by Kuraray Co., Ltd.) were mixed to obtain a gloss layer coating solution having a concentration of 25%.

<Coating of gloss layer> The coating solution of the gloss layer is coated on a support by a roll coater so as to have an absolute dry weight of 10 g / m ^2, and is pressed onto a heated finished surface. A coagulation liquid containing a cationic agent is applied to the coating film. Then, a glossy paper for inkjet recording was obtained.

1.6% by weight of borax was used as a coagulating liquid, and the following formula was used as a cationic polyallylamine condensation derivative.

[Chemical 1] Cationic polyallylamine condensate having primary and secondary ammonium bases represented by (trade name: Paracon PJ-
F, manufactured by Ohara Palladium Co., Ltd., pH = 10.8) A 1.0 wt% mixed aqueous solution was used to coagulate the gloss layer coating solution to obtain a coated paper.

Example 2: Same as Example 1, except that the cationic polyallylamine condensate was changed to 0.3% by weight.

Example 3: The same as Example 1 except that the cationic polyallylamine condensate was changed to 2.0% by weight.

Comparative Example 1: In Example 1, the pigment was silica (trade name: Syloid 72W, manufactured by Grace, particle size 3).
The same as in Example 1 except that the thickness was changed to μm).

Comparative Example 2: In Example 1, a dimethylamine epichlorohydrin resin (trade name: Paracon PJ, manufactured by Ohara Palladium, pH = 6.50) was used as the organic cation agent.
Was changed to 1.0% by weight to prepare glossy paper for inkjet recording.

Comparative Example 3: In Example 1, a dimethyldiallylammonium chloride resin (trade name: Himax SC-600L, manufactured by Hymo Co., Ltd., was used as the organic cation agent.
pH = 7.50) was changed to 1.0% by weight to prepare glossy paper for inkjet recording.

Comparative Example 4 In Example 1, the organic cation agent was used as a dimethylamine epichlorohydrin resin (trade name: Papiogen P-103, manufactured by Senka Co., pH = 5.70).
Was changed to 1.0% by weight to prepare glossy paper for inkjet recording.

Comparative Example 5: In Example 1, dimethylamine epichlorohydrin resin (trade name: DA-108, manufactured by Hoshiko Kagaku Co., pH = 10.8) was used as the organic cation agent.
The content was changed to 0% by weight to prepare a glossy paper for inkjet recording.

Comparative Example 6 In Example 1, 1.0 wt% of acrylamide / diallylamine hydrochloride resin (trade name: Sumirez Resin SR-1001, manufactured by Sumitomo Chemical Co., Ltd., pH = 4.40) was used as the organic cation agent. It changed and created the glossy paper for inkjet recording.

Comparative Example 7: In Comparative Example 2, the dimethylamine epichlorohydrin resin was changed to 2.0% by weight to prepare a glossy paper for ink jet recording.

Comparative Example 8: In Comparative Example 3, the dimethyldiallylammonium chloride resin was changed to 2.0% by weight to prepare a glossy paper for ink jet recording.

Comparative Example 9: In Comparative Example 4, the dimethylamine epichlorohydrin resin was changed to 2.0% by weight to prepare a glossy paper for ink jet recording.

Comparative Example 10: In Comparative Example 5, the dimethylamine epichlorohydrin resin was changed to 2.0% by weight to prepare a glossy paper for ink jet recording.

Comparative Example 11: In Comparative Example 6, the acrylamide / diallylamine hydrochloride resin was changed to 2.0% by weight to prepare a glossy paper for ink jet recording.

Comparative Example 12: 1.6 g of borax was used as a coagulating liquid.
Only gloss% was used to prepare glossy paper for inkjet recording.

With respect to the ink jet recording papers of Examples 1 to 3 and Comparative Examples 1 to 12 described above, white paper glossiness and ink jet recording suitability were evaluated by the following methods. The result is
It shows in Table 1.

Uniformity of glossiness: The glossiness was judged by observing the surface condition of the glossy paper from the lateral direction with the naked eye. The one with the highest uniformity was marked with ⊚, which was at the same level as the glossy paper based on photographic paper. Also, the one with the lowest uniformity is evaluated as x.

Printing density: Printing was carried out using an ink jet printer "PM-770C" manufactured by Seiko Epson Corporation. Then, the solid print densities of Bk, C, M, and Y were measured with a reflection densitometer, and the total value of the four colors was calculated and summarized.

Water resistance: Printing was performed using an ink jet printer "PM-770C" manufactured by Seiko Epson Corporation. Then, the printed sample is dipped in running water for about 5 minutes, then dried at room temperature and atmospheric pressure, and then the solid print densities of Bk, C, M, and Y are measured with a reflection densitometer. The ink residual rate was calculated. Furthermore, the average value of the ink remaining rates of the four colors was calculated and summarized.

[0053]

[Table 1]

As shown in the results of Table 1, the glossy paper for ink jet recording according to the present invention was practically sufficient in terms of glossy surface quality, printing quality, water resistance and the like. However, none of the samples of Comparative Examples satisfy the required characteristics.

[0055]

As is apparent from the above examples, the glossy paper for ink jet recording of the present invention has excellent uniformity of surface glossiness, printability and water resistance.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Akihisa Meguro             3-5-1, Nishi-Zao, Nagaoka-shi, Niigata Hokuetsu             Research Institute of Paper Manufacturing Co., Ltd. F-term (reference) 2C056 EA13 FC06                 2H086 BA01 BA15 BA21 BA33 BA35                       BA41 BA45

Claims (3)

[Claims] 1. A coating solution containing a pigment and a binder is applied to at least one surface of a base paper, and then the coated surface is coagulated with a coagulant, while the coated surface is in a wet state. A cast coated paper obtained by press-bonding the coating layer to a heated mirror-finished metal surface, which has a pH of 8 or more in the coagulating liquid and a primary and secondary ammonium salt in the molecule. A glossy paper for inkjet recording, comprising a cationic polyallylamine condensed derivative having 2. The inkjet recording according to claim 1, wherein the content of the cationic polyallylamine condensed derivative is in the range of 0.3 to 2.0% by weight in the coagulating liquid. Glossy paper. 3. The glossy paper for inkjet recording according to claim 1, wherein the pigment in the coating solution for the glossy layer is a composite of alumina and silica having an average particle size of 1 μm or less. .