JPH0632046A - Ink-jet recording paper - Google Patents

Abstract

PURPOSE:To provide aqueous ink-jet recording paper which is capable of high- speed printing. CONSTITUTION:This is aqueous ink-jet recording paper wherein an ink receptive coating layer consisting mainly of 60-90wt.% non-crystallizable pulverized silica of the whole coating of solid content, a viny alcohol copolymer containing a 5-30wt.% silanol group and a 0.1-10wt.% zirconium compound is provided on the surface of a substrate. With this construction, aqueous ink-jet recording paper wherein the surface is firm, printing is clear, ink absorption properties are excellent and water resistance and light resistance of a printed matter are improved is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording material for ink jet recording, which is used for a printer, a copy or the like using a water-based ink, and more specifically, color development, water resistance of an image,
The present invention relates to an improved color inkjet recording paper having excellent properties such as storage stability such as light resistance, dot shape, and coating strength.

[0002]

2. Description of the Related Art By improving the performance of an ink jet printer using water-based ink, especially the printing speed, resolution, gradation, etc., high speed absorption of ink, high absorption capacity, high density printing on recording materials , In addition to improving image quality,
Printed products are required to have higher properties such as water resistance and light resistance.

In order to meet such demands, for high density printing, the coating layer composed of non-silica and polymer binder is excellent in ink absorbability in printing with aqueous ink. JP-A-55-51583 discloses that a silyl group-containing modified polyvinyl alcohol is used as an inkjet recording medium having high water resistance, and JP-A-61-134290 discloses that a polycationic polymer electrolyte is used. JP-A-56-8
Japanese Patent Publication No. 4992 discloses a method using a polyvalent metal salt.
Japanese Unexamined Patent Publication (Kokai) No. 60-67190 discloses a method of using one or more kinds of water-soluble metal salts having a valence of 2 or more and a cationic organic substance.

[0004] However, silica is the best absorber at the present stage as an absorber capable of printing with high density and high image quality, having a high ink absorption speed, and not impairing the color development of the dye, and the From the viewpoint of improving the water resistance, it is known that the addition of a cationic resin can improve the water resistance by the ionic bond with a dye, but the light resistance is likely to decrease, and further, a polyvalent metal is used for improving the light resistance. Although a method of using a salt in combination has been proposed, none has been found that is satisfactory in performance.

[0005]

In view of the above situation, the present invention is capable of printing a high-resolution image having a high ink absorption speed, a large absorption capacity, and a sharp high resolution in an inkjet printer using a water-based ink. Moreover, it is an object of the present invention to provide an ink jet recording paper which is excellent in image storability and which solves the above-mentioned drawbacks of the prior art.

[0006]

Means for Solving the Problems As a result of various investigations to solve the above-mentioned drawbacks, the present inventors have found that a part of the pigment contains amorphous silica and a part of the adhesive contains Water resistance when an ink-receptive coating layer containing a vinyl alcohol copolymer containing a silanol group contains a zirconium compound in a specific proportion, and the ink-receptive coating layer is provided on at least one of the supports in a specific proportion. The inventors have found that an ink jet recording paper having excellent storage stability such as light resistance and capable of printing at high density and having excellent surface strength can be obtained, and completed the present invention.

The present invention comprises, on at least one surface of a support, 60 to 90% by weight of finely divided amorphous silica of total coating solids, and 5 to 30% by weight of a vinyl alcohol copolymer containing silanol groups. 2 to 20 g of an ink receptive coating layer containing 0.1 to 10% by weight of a zirconium compound as a main component
The present invention relates to a water-based inkjet recording paper characterized by being provided at a ratio of / m ² .

According to the present invention, by using a modified polyvinyl alcohol having excellent adhesiveness specifically to silica as a binder used in the ink-receptive coating layer, the amorphous component which is the main component of the pigment is used. By firmly adhering the finely divided silica and allowing the zirconium compound to exist,
At the same time that the printed water-based ink is adsorbed on the pigment, the effect of preventing redissolution in water can be exhibited.

The polyvinyl alcohol copolymer containing a silanol group as an adhesive used in the present invention is obtained by copolymerizing a vinyl compound containing silicon and vinyl acetate,
By saponification, vinyl acetate units are converted to vinyl alcohol and silicon-containing units are converted to silanol groups, respectively (JP-A-58-599203), in which the silicon-containing monomer is 0. .1 to 1.0 mol%
Only a very small amount should be copolymerized. Since the polyvinyl alcohol copolymer containing a silanol group specifically and firmly adheres to silica, a sufficient coating strength can be realized with a small amount that does not impair color development and resolution.

In the present invention, in addition to the polyvinyl alcohol copolymer containing a silanol group, a natural or processed adhesive such as polyvinyl alcohol, starch derivative, cellulose derivative or the like as an adhesive, and an acrylic adhesive,
It can be appropriately selected from water-based synthetic adhesives such as styrene-butadiene-based adhesives and used in combination.

The adhesive, including the amount of polyvinyl alcohol copolymer containing silanol groups, comprises 5 to 3 of the total coating solids.
It is in the range of 0% by weight. Even if the amount of the adhesive is 30% by weight or more, the strength does not improve so much, and the ratio of silica is lowered to deteriorate the image. On the other hand, if the amount of the adhesive is 5% by weight or less, the coating film strength is unsatisfactory. It becomes sufficient and is not preferable.

In the present invention, a zirconium compound is added as one of the components constituting the ink receptive coating layer in order to improve the water resistance of the image. This zirconium compound is selected from zirconium oxychloride, zirconium carbonate, ammonium zirconium carbonate, zirconium acetate, ammonium zirconium acetate and the like and is used as a mixture of one or more compounds.

The zirconium compound is added in an amount of 0.1 to 10% by weight, preferably 0.2 to 10% by weight, based on the total solid content of the coating material. If the content of the zirconium compound is more than 10% by weight, the ink absorbency is lowered and the ink drying property is insufficient, and if it is less than 0.1% by weight, the water resistance of the printed image is insufficient.

In addition to the zirconium compound, a quaternary ammonium salt of polyethyleneimine for the purpose of improving water resistance, an acrylic or methacrylic acid ester copolymer having a quaternary ammonium group introduced is used to the extent that the light resistance is not affected. Can also be added to.

The pigment used in the present invention is known to give a clear image when used in ink jet recording, has a high oil absorption and a high specific surface area, and has a secondary particle of 1
Amorphous finely divided silica of ˜6 μm is the best. This fine silica powder is used in an amount of 60 to 90% by weight based on the total solid content of the coating material, and if the fine silica powder is less than 60% by weight, the absorption capacity of the ink decreases, the ink bleeding and the dot diameter increase, which is not preferable. If it is more than 90% by weight, the image quality is good, but the strength of the coating film is lowered, which causes a problem in practical use.

Other white pigments can be used in combination depending on the purpose of use of the paper and the required performance of the printer. Examples of these white pigments include pigments generally used for paper coating, such as zeolite, calcium carbonate, diatomaceous earth, kaolin clay, calcined clay, talc, aluminum hydroxide, and organic pigments (plastic pigments). Further, it is necessary to uniformly disperse the pigment in water to form a coating material. For that purpose, for example, a usual dispersant such as sodium polyallylate, phosphate, and surfactant is added. It is suitable.

In the ink-receptive coating layer of the present invention, the above-mentioned constituents are uniformly dispersed in water by a conventional method to prepare a coating solution, which is applied to a bar coater, a blade coater, an air knife coater, a gravure coater or the like. According to the coating method used, a coating amount of 2 to 20 is applied to at least one surface of the support.
It is obtained by providing it at a ratio of g / m ² . If the coating amount is less than 2 g / m ² , the image uniformity and the image density will be insufficient, and if it is more than 20 g / m ² , the coating strength will decrease and at the same time the improvement in performance will saturate and the cost will increase. It is not preferable.

The support used in the present invention is a paper made of ordinary natural pulp, a plastic film sheet of polypropylene, polyethylene, polyester or the like, synthetic fiber,
Any of synthetic pulp and so-called synthetic paper obtained by converting a synthetic resin film into a pseudo paper may be used. The thickness of the support is 10-200μ
The m and the basis weight are preferably in the range of 10 to ²⁰⁰ g / m ² .

[0019]

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,% means% by weight in terms of solid content.

Example 1 A paint-1 having the following composition was prepared to a concentration of 18% by weight,
Basis weight of 65 g / m ² on one side of high quality paper
An ink jet recording paper having an ink-receptive coating layer was prepared by coating with a bar coater at a ratio of m ² and drying. Paint-1 Amorphous finely divided silica (Fineseal: Tokuyama Soda) 82.0% Silanolated polyvinyl alcohol (R-1130: Kuraray) 16.0% Zirconium acetate (Tokyo Kasei) 0.8% Polyacrylic acid Soda (dispersant: manufactured by Toagosei) 1.2%

Example 2 A paint-2 having the composition shown below was prepared to a concentration of 18% by weight,
Basis weight of 65 g / m ² on one side of high-quality paper 10 g in terms of solid content
Coated with a bar coater at a ratio of / m ² and dried,
An ink jet recording paper having an ink receptive coating layer was prepared. Paint-2 Amorphous finely divided silica (Fineseal: Tokuyama Soda) 75.0% Silanolated polyvinyl alcohol (R-1130: Kuraray) 23.6% Zirconium ammonium carbonate (Tokyo Kasei) 0.2% Polyacryl Acid soda 1.2%

Example 3 A paint-3 having the composition shown below was prepared to a concentration of 18% by weight,
20g in terms of solid content on one side of fine paper with a basis weight of 65g / m ^2.
Coated with a bar coater at a ratio of / m ² and dried,
An ink jet recording paper having an ink receptive coating layer was prepared. Paint-3 Amorphous finely divided silica (Mizukasil: manufactured by Mizusawa Chemical) 67.5% Silanolated polyvinyl alcohol (R-1130: manufactured by Kuraray) 30.0% Ammonium zirconium carbonate (manufactured by Tokyo Kasei) 1.0% Polyacrylic acid Soda 1.5%

Example 4 A paint-4 having the composition shown below was prepared to a concentration of 18% by weight,
Basis weight of 65 g / m ² on one side of high quality paper
An ink jet recording paper having an ink-receptive coating layer was prepared by coating with a bar coater at a ratio of m ² and drying. Paint-4 Amorphous finely divided silica (Fineseal: Tokuyama Soda) 60.0% Precipitating calcium carbonate (PZ: Shiraishi Kogyo) 26.5% Silanolated polyvinyl alcohol (R-1130: Kuraray) 10.0 % Zirconium acetate (manufactured by Tokyo Kasei) 2.0% Sodium polyacrylate 1.5%

Example 5 A paint-5 having the composition shown below was prepared to a concentration of 18% by weight,
Basis weight of 65 g / m ^{2 2} g / m solid surface on one side
An ink jet recording paper having an ink-receptive coating layer was prepared by coating with a bar coater at a ratio of m ² and drying. Paint-5 Amorphous finely divided silica (Fineseal: Tokuyama Soda) 90.0% Silanolated polyvinyl alcohol (R-1130: Kuraray) 5.0% Zirconium ammonium carbonate (Tokyo Kasei) 3.5% Polyacryl Acid soda 1.5%

Example 6 A paint-6 having the composition shown below was prepared to a concentration of 18% by weight,
Basis weight of 65 g / m ² on one side of high quality paper
An ink jet recording paper having an ink-receptive coating layer was prepared by coating with a bar coater at a ratio of m ² and drying. Paint-6 Amorphous fine powder silica (Fineseal: Tokuyama Soda) 78.5% Silanolated polyvinyl alcohol (R-1130: Kuraray) 10.0% Ammonium zirconium carbonate (Tokyo Kasei) 10.0% Polyacryl Acid soda 1.5%

Comparative Example 1 A paint-7 having the composition shown below was prepared to a concentration of 18% by weight,
Basis weight of 65 g / m ² on one side of high quality paper
An ink jet recording paper having an ink-receptive coating layer was prepared by coating with a bar coater at a ratio of m ² and drying. Paint-7 Amorphous finely divided silica (Fineseal: Tokuyama Soda) 82.5% Silanolated polyvinyl alcohol (R-1130: Kuraray) 16.5% Sodium polyacrylate 1.0%

Comparative Example 2 A paint-8 having the following composition was prepared to a concentration of 18% by weight,
Basis weight of 65 g / m ² on one side of high quality paper
An ink jet recording paper having an ink-receptive coating layer was prepared by coating with a bar coater at a ratio of m ² and drying. Paint-8 Amorphous fine silica (Fineseal: Tokuyama Soda) 73.5% Silanolated polyvinyl alcohol (R-1130: Kuraray) 10.0% Ammonium zirconium carbonate (Tokyo Kasei) 15.0% Polyacryl Acid soda 1.5%

Comparative Example 3 A paint-9 having the composition shown below was prepared to a concentration of 18% by weight,
Basis weight of 65 g / m ² on one side of high quality paper
An ink jet recording paper having an ink-receptive coating layer was prepared by coating with a bar coater at a ratio of m ² and drying. Paint-9 Amorphous fine powder silica (Fineseal: Tokuyama Soda) 50.0% Silanolated polyvinyl alcohol (R-1130: Kuraray) 35.0% Zirconium ammonium carbonate (Tokyo Kasei) 13.5% Polyacryl Acid soda 1.5%

Comparative Example 4 A coating material 10 having the composition shown below was prepared to a concentration of 18% by weight, and was added to one surface of a fine paper having a basis weight of 65 g / m ^{2 in} an amount of 5 in terms of solid content.
An inkjet recording paper having an ink-receptive coating layer was prepared by applying the composition at a rate of g / m ² using a bar coater and drying. Paint-10 Amorphous fine silica (Fineseal: Tokuyama Soda) 95.0% Silanolated polyvinyl alcohol (R-1130: Kuraray) 2.0% Zirconium ammonium carbonate (Tokyo Kasei) 1.5% Polyacryl Acid soda 1.5%

Comparative Example 5 A paint-11 having the composition shown below was prepared to a concentration of 18% by weight, and 5% in terms of solid content was applied to one side of a fine paper having a basis weight of 65 g / m ^2.
An inkjet recording paper having an ink-receptive coating layer was prepared by applying the composition at a rate of g / m ² using a bar coater and drying. Paint-11 Precipitable calcium carbonate (PZ: Shiraishi Kogyo) 82.0% Polyvinyl alcohol (PVA117: Kuraray) 17.0% Sodium polyacrylate 1.0%

Comparative Example 6 A paint-12 having the composition shown below was prepared to a concentration of 18% by weight, and 5% in terms of solid content was calculated on one side of a fine paper having a basis weight of 65 g / m ^2.
An inkjet recording paper having an ink-receptive coating layer was prepared by applying the composition at a rate of g / m ² using a bar coater and drying. Paint-12 Amorphous finely divided silica (Fineseal: Tokuyama Soda) 82.0% Silanolated polyvinyl alcohol (R-1130: Kuraray) 16.0% Polyethyleneimine quaternary ammonium salt (Nippon Shokubai Kagaku) 0 .8% Sodium polyacrylate 1.2%

Table 1 shows the evaluation results of these ink jet recording sheets. The recording characteristics of the inkjet recording paper were evaluated for color density and ink dryness using an inkjet printer (Canon word processor, α-40).

The color density was measured on the printed matter with a Macbeth densitometer. The light resistance of this printed material was evaluated by irradiating the recording paper with a xenon fade meter manufactured by Atlas Co., Ltd. at 55 ° C. and 65% RH for 80 hours, and measuring the residual density ratio with respect to the initial density. As for the evaluation, those with excellent performance are ○,
The ones with general quality are shown as Δ, and those with defects that cause problems in use are shown as x. A density higher than 1.2 is ◯, 1.1 to 1.2 is Δ, and a lower than 1.1 is x, and the light resistance is ◯ when the residual concentration rate is 80% or more, and 70% or more. Less than 80% is △, less than 70% is ×
And

Regarding the ink drying property, after 1 minute of printing, the printed surface was pressure-bonded with paper and the state of ink transfer was observed.
Water resistance was evaluated by printing characters with the above printer, immersing this recording paper in still water for 1 minute, and observing the state of re-elution of the printed matter into water. The strength of the ink-receptive coating layer was organoleptically evaluated by sticking a commercially available cellophane tape to the surface of the coating layer and observing the degree of peeling of the coating layer when peeling the tape. In the evaluation of ink drying property, water resistance and coating film strength, good performance is indicated by ◯, normal quality is indicated by Δ, and defects having problems in use are indicated by x.

[0035]

[Table 1]

As is apparent from Table 1, according to the present invention, 60 to 90% by weight of amorphous finely divided silica and 5 parts by weight of a silanol group-containing vinyl alcohol copolymer are used based on the total solid content of the coating material.
30% by weight and zirconium compounds by providing 2 to 20 g / m ² on at least one surface of a support an ink-receptive coating layer containing a 0.1 to 10 wt%, the recording of the image by the ink jet recording Density, ink absorption,
The light resistance, water resistance and coating film strength can be satisfied (Examples 1 to 6).

However, if the amount of amorphous fine silica is less than 60% by weight, the recording density and the ink absorbency are lowered (Comparative Example 3), and if the amount of amorphous fine silica is more than 90% by weight, the strength of the coating film is lowered. (Comparative example 4).

If the vinyl alcohol copolymer containing a silanol group is less than 5% by weight, the coating strength is lowered (Comparative Example 4), and if it is more than 30% by weight, the recording density and the ink absorptivity are lowered (comparison). Example 3).

Further, the zirconium compound is 0.1% by weight.
If it is less, the water resistance of the image is lost (Comparative Example 1), 1
When it is more than 0% by weight, the image density and the ink absorbency are insufficient (Comparative Examples 2 and 3).

Unless the above-mentioned amorphous fine powder silica and the silanol group-containing vinyl alcohol copolymer are used, the image density and the ink absorbency are lowered, which is not preferable (Comparative Example 5). When a cationic resin is used instead of the zirconium compound, the light resistance of the image is lowered (Comparative Example 6).

[0041]

EFFECT OF THE INVENTION The ink jet recording paper of the present invention has a strong surface, clear printing and excellent ink absorbency, improves the water resistance and light resistance of the printed matter, and eliminates the drawbacks of conventional recording papers. It has the effect of enabling a high-resolution, high-speed and general-purpose inkjet printing system.

Claims (1)

[Claims] 1. At least one surface of the support, and 60 to 90% by weight of total coating solids of amorphous finely divided silica, and 5 to 5.
An ink-receptive coating layer containing 30 wt% of a silanol group-containing vinyl alcohol copolymer and 0.1 to 10 wt% of a zirconium compound as main components was provided at a rate of ² to 20 g / m ^2. Characteristic water-based inkjet recording paper.