JPH06158596A - Paper for ink jet recording - Google Patents

Abstract

(57) [Abstract] [Purpose] A strong surface, clear printing, excellent ink absorption, uniform image quality, excellent water resistance of printed matter, high resolution, high speed and general-purpose inkjet An inkjet recording sheet that can be printed is provided. [Structure] A pigment having an oil absorption amount (described in JIS K 5101) of 60 to 290 ml / 100 g, an esterified starch, and a water-insoluble cationic polymer are main components on at least one surface of a paper mainly composed of cellulose pulp. And an ink receptive coating layer containing

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording paper, and more particularly to an aqueous ink jet recording paper having a high quality and ink receptive coating layer having excellent color image characteristics. .

[0002]

2. Description of the Related Art The performance of ink jet printers using water-based inks, especially in the case of color recording, has been improved by improving printing speed, resolution, saturation and the like, so that high-speed absorptivity, high absorptive capacity and evenness are achieved even on recording paper. With the demand for higher characteristics such as various dot diameters, so-called coating type inkjet recording paper having an ink-receptive coating layer on the surface has been developed.

For example, JP-A-57-36692 discloses a basic latex polymer, a polyamide-epichlorohydrin resin and gelatin as binders.
A method of coating or impregnating aluminum silicate, calcium carbonate or the like as an inorganic pigment is disclosed. However, in recent years, with the development of colorization, the ink absorption speed,
There has been a demand for a paper having uniform print dots, high-quality print quality, and coating strength.

Further, Japanese Unexamined Patent Publication (Kokai) No. 62-158084 discloses a method for producing an ink jet recording medium having high water-based ink absorbency, color reproducibility and color density, using synthetic fine particle silica as a highly oil absorbing pigment. ing. When a coating layer containing a liquid-absorbing pigment such as synthetic fine particle silica as a main component is provided on the surface of a paper containing cellulose pulp as a main component, the ink absorbency is high and uniform dots are obtained.
Since a highly oil-absorbing pigment is used, the strength of the coating film tends to decrease, and the amount of binder needs to be increased. However, if the amount of binder is increased, a new problem such as a decrease in ink absorption occurs, and the coating amount of the ink absorption layer is separately set to 15 to 20 g /
A method such as increasing to m ² is required.

On the other hand, from the viewpoint of cost, there is a strong demand for a so-called lightweight coating type ink jet recording medium which has an ink receptive coating layer on the surface particularly thinly and has sufficient performance. However, if the coating layer is thin, part of the pulp may be exposed on the surface or the coating layer may become thick, resulting in uneven absorption of ink. There has been a problem to improve the strength of the ink and the uniform absorption of the ink.

[0006]

DISCLOSURE OF THE INVENTION The present invention is an ink jet recording paper which uses an aqueous ink and is capable of printing a high quality image at high speed, has a uniform ink absorption, and is excellent in coating strength. Is to provide. As a result of various investigations by the present inventors to solve the above-mentioned drawbacks, an inkjet recording paper which can print high-quality images at high speed, has uniform ink absorption, and has excellent coating strength. The present invention has been completed and the present invention has been completed.

[0007]

An ink jet recording paper according to the present invention comprises a pigment having an oil absorption of 60 to 290 ml / 100 g according to JIS K 5101 and an ester on at least one surface of a paper containing cellulose pulp as a main component. It is obtained by providing an ink-receptive coating layer containing modified starch and a water-insoluble cationic polymer as main components.

In the case of color printing by an ink jet method using a water-based ink, since inks of 3 to 4 colors are printed at high speed, the ink receptive coating layer has a large ink absorption capacity and a high absorption speed in a short time. Is required. Further, recent inkjet recording papers are desired to be papers close to plain papers, and therefore, it is desired that the coating amount of the ink-receptive coating layer be as small as possible. When the ink-receptive coating layer has a low coating amount, the coating strength, the ink absorption speed, and the capacity are important factors. For this reason, it is preferable that the pigment used in the ink-receptive coating layer has a high oil absorption amount, which is considered as a measure of ink absorbency.

The pigment used in the present invention has a high ink absorptivity and gives a clear image when used in ink jet recording. For example, silica, clay, calcium carbonate, talc, barium sulfate and aluminum silicate are used. Inorganic pigments such as talc, talc, diatomaceous earth, and titanium oxide, and organic pigments such as urea resins, polystyrene pigments, and acrylic pigments with an oil absorption of 60 to 290 ml according to JIS K 5101.
/ 100 g of one or more pigments are used in combination. If the oil absorption of the pigment used is less than 60 ml / 100 g, the ink absorbency will decrease and the oil absorption will be 29
If it is larger than 0 ml / 100 g, the strength of the coating film is lowered, which is not preferable.

The binder used in the ink-receptive coating layer of the present invention has high absorptivity or penetrability with respect to ink and is capable of adhering a highly oil-absorbing pigment. It is necessary to record high-quality images without uneven absorption. As a result of diligent studies on various binders, the present inventors have found that the above performance is satisfied by using esterified starch as a water-soluble binder and a cationic polymer as a water-insoluble binder as main components. It was

Examples of the water-soluble esterified starch used in the present invention include organic acids such as acetic acid esterified starch, succinic acid esterified starch, phosphoric acid esterified starch, xanthogenic acid esterified starch and nitric acid esterified starch, and inorganic acids. Starch esterified with is preferred. The esterified starch is grafted with a synthetic polymer such as polyvinyl acetate, polymethylmethacrylate, polyacrylic amide, polyacrylonitrile or polyacrylic acid, or 2-dimethylaminoethyl chloride, 2-diethylaminoethyl chloride, 2- It is also possible to modify with a cationizing agent such as dimethylaminoisopropyl chloride.

The water-insoluble cationic polymer used in the present invention includes a cationic vinyl acetate copolymer emulsion, a cationic vinyl acetate / acrylic acid ester copolymer emulsion, a cationic vinyl acetate / veova copolymer emulsion, and the like. Represented by at least one cationic monomer having a copolymerization main component containing a fatty acid vinyl ester, an ethylenically unsaturated group, and a tertiary amino group or a quaternary ammonium group. , A cationic copolymer component and a cationic copolymer component.

The binder used in the ink receptive coating layer in the present invention is used in the range of 10 to 60% by weight based on the total coating solids. Even if the amount of the binder used is more than 60% by weight, the strength is not improved so much, the ink absorbency is rather lowered, and the image quality is deteriorated. If the amount of the binder used is less than 10% by weight, the strength of the coating film becomes insufficient, which is not preferable.

The ratio of the water-soluble esterified starch and the water-insoluble cationic polymer in the total binder is 40 in the former case.
.About.95% by weight, the latter 60 to 5% by weight are preferably used. When the content of the water-soluble esterified starch is more than 95% by weight, the coating film strength is reduced. Further, if the amount of the water-insoluble cationic polymer is more than 60% by weight, the ink absorbency is lowered, which is not preferable.

In the present invention, in addition to water-soluble esterified starch and water-insoluble cationic polymer, polyvinyl alcohol, modified polyvinyl alcohol such as silanol group-modified, and natural or water-based synthetic binder such as cellulose derivative are appropriately selected. It can be selected and used.

The paper as the support used in the present invention is produced by using ordinary wood pulp as a main raw material. The filler may or may not be internally added. Further, it is preferable to use a paper having a Steckigt sizing degree of 1 to 40 seconds [based on a basis weight of 64 g / m ² ] because the absorptivity is excellent. If the sizing degree is too low, there is concern that strike-through of printed images, irregular spreading of ink, and deterioration of water resistance of dyes may occur. If the sizing degree is too high, the ink absorbency becomes insufficient, and in order to maintain the absorbency, it is necessary to make the ink receiving layer much thicker than 10 g / m ² .

The thickness of the support is determined by the end use of the print, but is 15 to 200 μm, and the basis weight is 20 to 20.
0 g / m ² is preferably used. Mayer bar, air knife, blade on at least one surface of the support,
Ink-receptive coating layer 1 by coating method such as roll coater
Coating at a rate of 10 g / m ^{2 to} prepare an inkjet paper. When the coating amount of the ink-receptive coating layer is less than 1 g / m ² , the uniformity of the image is deteriorated, and when it is more than 10 g / m ² , the effect is saturated and the cost is increased, which is not preferable.

[0018]

The present invention will be described in more detail with reference to the following examples, but of course the present invention is not limited thereto. In the following examples,% means% by weight in terms of solid content.

Example 1 20 parts of light calcium carbonate was added to a suspension of 100 parts of bleached hardwood kraft pulp (whiteness 91%) in water, 1 part of cationic starch, alkenyl succinic anhydride neutral sizing agent. 05 parts were added to obtain a papermaking raw material. A fine paper of 64 g / m ² was produced by a conventional method using a Fourdrinier cylinder type paper machine. Whiteness 92%, calcium carbonate content 15.0%,
The Stoeckigt sizing degree was 5 seconds and the pH of the paper was 6.5. On the surface of the paper, 1 of paint-1 having the composition shown below is used.
An ink jet recording paper having an ink receptive coating layer was prepared by coating and drying at a rate of 0 g / m ² using a bar coater.

Paint-1 Fine silica (Fineseal manufactured by Tokuyama Soda, oil absorption amount 200 ml / 100 g) 60% Esterified starch MS5300 (acetate ester type, manufactured by Nippon Shokubai Co., Ltd.) 35% Cationic polymer K-13 (manufactured by Kanebo NSC) 5 %

Example 2 On the surface of the paper, 5 g of a paint-2 having the composition shown below was applied.
It was coated at a ratio of m ² using a bar coater and dried to prepare an ink jet recording paper having an ink receptive coating layer. Paint-2 Fine silica (Fineseal made by Tokuyama Soda Oil absorption 200ml / 100g) 60% Esterified starch MS5300 (Acetate ester type, made by Nippon Shokuhin Kako) 20% Cationic polymer K-13 (made by Kanebo NSC) 20%

Example 3 The surface of this paper was coated with 5 g of a paint-3 having the composition shown below.
It was coated at a ratio of m ² using a bar coater and dried to prepare an ink jet recording paper having an ink receptive coating layer. Paint-3 Fine silica (Fineseal, manufactured by Tokuyama Soda, oil absorption 200 ml / 100g) 60% Esterified starch MS5300 (acetate ester, manufactured by Nippon Shokubai Co., Ltd.) 20% Cationic polymer K-13 (manufactured by Kanebo NSC) 20%

Example 4 10 g of paint-4 having the composition shown below was applied to the surface of the paper.
An inkjet recording paper having an ink receptive coating layer was prepared by coating and drying at a ratio of / m ² using a bar coater. Paint-4 Fine silica (Fineseal manufactured by Tokuyama Soda Oil absorption 200ml / 100g) 60% Esterified starch MS4600 (phosphate ester type, manufactured by Nippon Shokuhin Kako) 30% Cationic polymer K-11 (manufactured by Kanebo NSC) 5% Polyethylene Imine quaternary ammonium salt (Nippon Shokubai Kagaku) 5%

Example 5 10 g of paint-5 having the composition shown below was applied to the surface of the paper.
An inkjet recording paper having an ink receptive coating layer was prepared by coating and drying at a ratio of / m ² using a bar coater. Paint-5 Precipitating calcium carbonate (Univers 70 Shiraishi Kogyo 70ml / 100g oil absorption) 60% Esterified starch Z300 (Acetate ester type, Nitto Kagaku) 20% Cationic polymer K-11 (Kanebo NSC) 20%

Comparative Example 1 10 g of paint-6 having the composition shown below was applied to the surface of the paper.
An inkjet recording paper having an ink receptive coating layer was prepared by coating and drying at a ratio of / m ² using a bar coater. Paint-6 Fine silica (Fineseal, manufactured by Tokuyama Soda, oil absorption 200ml / 100g) 60% Esterified starch MS5300 (acetic ester, manufactured by Nippon Shokubai Co., Ltd.) 40%

Comparative Example 2 10 g of paint-7 having the composition shown below was applied to the surface of the paper.
An inkjet recording paper having an ink receptive coating layer was prepared by coating and drying at a ratio of / m ² using a bar coater. Paint-7 Fine silica (Fineseal, manufactured by Tokuyama Soda, oil absorption 200 ml / 100g) 60% Cationic polymer K-13 (manufactured by Kanebo NSC) 40%

Comparative Example 3 10 g of paint-8 having the composition shown below was applied to the surface of the paper.
An inkjet recording paper having an ink receptive coating layer was prepared by coating and drying at a ratio of / m ² using a bar coater. Paint-8 Precipitating calcium carbonate (PC Shiraishi industry oil absorption 40ml / 100g) 60% Esterified starch MS5300 (acetate ester, Nippon Food Chemical Co., Ltd.) 20% Cationic polymer K-13 (Kanebo NSC) 20%

Comparative Example 4 10 g of the paint-9 having the composition shown below was applied to the surface of the paper.
An inkjet recording paper having an ink receptive coating layer was prepared by coating and drying at a ratio of / m ² using a bar coater. Paint-9 Fine silica (Zeosil Taki Chemical, oil absorption 300ml / 100g) 60% Esterified starch MS5300 (acetate ester, manufactured by Nippon Shokuhin Kako) 20% Cationic polymer K-13 (Kanebo NSC) 20%

Comparative Example 5 A paint-10 having the composition shown below was applied to the surface of the above-mentioned paper.
coating with a bar coater at a rate of g / m ² and drying,
An inkjet recording paper having an ink receptive coating layer was prepared. Paint-10 Fine silica (Fineseal manufactured by Tokuyama Soda Oil absorption 200ml / 100g) 60% Etherified starch GUM 295 (Hydroxyethyl 20% ether system, manufactured by Nissei Kyoyasu) Cationic polymer K-13 (Kanebo NSC) 20%

COMPARATIVE EXAMPLE 6 On the surface of the paper, 10 paints 11 having the composition shown below were prepared.
coating with a bar coater at a rate of g / m ² and drying,
An inkjet recording paper having an ink receptive coating layer was prepared. Paint-11 Fine silica (Zeo-Seal Taki Chemical Co., Ltd. oil absorption amount 300 ml / 100 g) 60% Oxidized starch Ace A (Oji Corn Starch) 20% Cationic polymer K-13 (Kanebo NSC) 20%

Table 1 shows the evaluation results of these ink jet recording sheets. Inkjet recording paper is a color inkjet printer (Hewlett Packard D
Esk Writer C) was used to print in blue and the uniformity of printing was visually evaluated.

In addition, with the sharp color inkjet printer IO735X, cyan, magenta, yellow, blue,
Red, green, and black were made to be adjacent to each other, and printed in a strip shape, and the degree of ink bleeding between the respective colors was visually evaluated as the ink absorbency.

The water resistance was evaluated by printing with the above color ink jet printer (DeskWriter C manufactured by Hewlett Packard), immersing in still water for 1 minute, and observing the state of re-elution of the printed matter.

The coating strength was evaluated by rubbing the ink receptive coating layer with black paper and visually evaluating the transfer of the coating to black paper.

The evaluation of the printing uniformity, ink absorbency, water resistance, and coating strength is ◯ for excellent performance, Δ for ordinary quality, and × for defects having problems in use. Show as.

[0036]

[Table 1]

As is apparent from Table 1, according to the present invention, a pigment having an oil absorption of 60 to 290 ml / 100 g, an esterified starch, and a water-insoluble cation are provided on at least one surface of a paper containing cellulose pulp as a main component. By providing an ink receptive coating layer containing a water-soluble polymer as a main component, it is possible to satisfy the uniformity of an image by ink jet recording, ink absorbency, water resistance and coating film strength (Example 1).
~ 5), the oil absorption of the pigment of the ink receptive coating layer is 60 ml
If it is less than 100 g / 100 g, the ink absorbency is lowered (Comparative Example 3), and if it is more than 290 ml / 100 g, the coating strength is lowered (Comparative Example 4).

If the esterified starch which is the binder of the ink-receptive coating layer is not added, the uniformity of the image and the ink absorption are lowered (Comparative Example 1), and the esterified starch and the oxidized starch are used instead of the esterified starch. If it is used, the uniformity of the image and the coating film strength are lowered (Comparative Examples 4 and 5). In addition, when the water-insoluble cationic polymer is not added, the coating film strength and water resistance decrease (Comparative Example 2).

[0039]

The ink jet recording paper of the present invention has a strong surface, clear printing, excellent ink absorption, uniform image quality, and excellent water resistance of the printed matter. It has the effect of enabling high-resolution, high-speed, and general-purpose inkjet printing systems that cannot be achieved with recording paper.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical display location D21H 27/00 7199-3B D21H 5/00 Z

Claims (1)

[Claims] 1. A pigment having an oil absorption of 60 to 290 ml / 100 g according to JIS K 5101, esterified starch and a water-insoluble cationic polymer are provided on at least one surface of a paper containing cellulose pulp as a main component. An ink jet recording paper, which is provided with an ink receptive coating layer containing a main component.