JP2000043406A - Inkjet recording sheet - Google Patents

Abstract

(57) [Problem] To provide an ink jet recording sheet which has high ink absorbency and low bleeding in an ink jet recording sheet, and has no sticky printing portion. An image receiving layer contains a water-soluble polymer and 1% by weight or more of a carboxylic acid based on the water-soluble polymer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image receiving member used for a printer or a plotter in an ink jet recording system, and more particularly, it can be used as an ink jet image receiving member having a photographic paper-like gloss of a photograph which is highly demanded in color recording. Related to a simple image receiving body.

[0002]

2. Description of the Related Art In recent years, the demand for ink jet printers has increased with the spread of computers and digital photographs. However, the image quality has also been sharply improved and is now approaching that of silver halide photography. Applications include digital photo and poster output, advertising, billboards, drafting, and presentations, but especially for small copies.
It is a great advantage that output can be performed at lower cost than using photographs and prints.

In the ink jet system using water-based ink, the quality has been improved due to the design of the print head, the improvement of the ink, and the speed of printing, and the reliability has been improved. At the same time, the recording material also has high ink absorption and high color. A design that satisfies the density and color reproducibility is required.

[0004] Ink-jet recording materials are generally those in which an ink absorbing layer is provided on a support. The absorbing layer has a porous structure, which absorbs ink by capillary action, and absorbs ink by swelling. Known polymer types are known. In particular, the polymer type is characterized by being capable of obtaining a photographic image with high gloss.

Examples of ink-jet recording materials using polymers include, for example, JP-A-57-38185 and JP-A-57-38185.
Polyvinylpyrrolidone, vinylpyrrolidone-vinyl acetate copolymer described in JP-A-2-184879, JP-A-60-168651, and JP-A-60-17114.
Nos. 3 and 61-134290, resin compositions mainly composed of polyvinyl alcohol, and copolymers of vinyl alcohol and olefin or styrene and maleic anhydride described in JP-A-60-234879. Coalescence, crosslinked product of polyethylene oxide and isocyanate disclosed in JP-A-61-74879, mixture of carboxymethyl cellulose and polyethylene oxide described in JP-A-61-181679, JP-A-61-132377 A polymer obtained by grafting methacrylamide to polyvinyl alcohol shown in
Acrylic polymer having a carboxyl group disclosed in JP-A-62-220383;
Various ink-absorbing polymers such as a polyvinyl acetal polymer disclosed in JP-A-82-82 and a cross-linkable acrylic polymer described in JP-A-4-282282 and JP-A-4-285650 have been proposed. Gelatin, which is a natural polymer, is often used because a strong film can be obtained. As described in JP-A-2-1359, an image receptor using a phthalated gelatin derivative in which the amino group of gelatin is inactivated has been proposed.
In Japanese Patent Application Laid-Open No. H11-264, an image receiver using a carbonyl-modified gelatin having a residual amount of free amino groups of 50% or less is proposed.

However, an ink jet recording sheet comprising an ink image receiving layer containing the above-mentioned water-soluble polymer as a main component has a problem that fine lines are blurred after printing. In particular, the above problem became remarkable when printing was performed with pigment ink.

[0007]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an ink jet recording sheet having a polymer ink jet image receiving layer, which is excellent in absorptivity even when printed with a pigment ink and has no bleeding. It is to provide.

[0008]

An object of the present invention is to provide an ink-jet recording sheet characterized in that the image-receiving layer contains a water-soluble polymer and 1% by weight or more of a carboxylic acid based on the water-soluble polymer. This was achieved by providing an ink jet recording sheet.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The water-soluble polymer used in the present invention is gelatin,
Examples thereof include polyvinylpyrrolidone, polyvinyl alcohol, polyacrylamide, carboxymethylcellulose, and hydroxypropylcellulose, and it is preferable to use gelatin. Its content is 5 to 15 g / m ^2, preferably a 8-12 g / m ^2.

The carboxylic acid used in the present invention is preferably water-soluble, and preferably has 6 or less carbon atoms other than a carboxy group. For example, monocarboxylic acid having one carboxy group in one molecule such as acetic acid, propionic acid, benzoic acid, etc., dicarboxylic acid having two carboxy groups such as phthalic acid, succinic acid and malic acid, monomethyl succinate A half ester in which one of two carboxy groups such as an ester is esterified is exemplified. These carboxylic acids may be salts with alkali metals, but preferably those which are not salts.

Among the above carboxylic acids, the carboxylic acid represented by the above formula 1 is particularly preferred. In the formula, L is an aliphatic group or aromatic group having 6 or less carbon atoms. These groups may be further substituted with a hydroxyl group, a carboxy group, an amino group and the like. Specific examples of Chemical Formula 1 include malonic acid, succinic acid, maleic acid, glutaric acid, adipic acid, suberic acid, malic acid, tartaric acid,
Citric acid and the like. Among them, L is more preferably one having 2 or less carbon atoms. For example,
Malonic acid, succinic acid, malic acid, tartaric acid, citric acid and the like can be mentioned. The effect is exhibited when the content of these carboxylic acids is 1% by weight or more based on the polymer, and preferably 3% by weight.
Not less than 20% by weight.

In the present invention, the ink receiving layer may be composed of only one layer composed of a water-soluble polymer.
It may have a configuration of more than layers. Examples of two or more layers include an embodiment in which two or more layers made of a water-soluble polymer are stacked and an embodiment in which a layer made of a porous pigment such as silica or alumina sol and a layer made of a water-soluble polymer are stacked.
When the ink receiving layer has two or more layers, the total amount of the carboxylic acid is adjusted to 1% by weight or more based on the total amount of the water-soluble polymer. In the case of the two-layer structure, the water-soluble polymer and the carboxylic acid may be contained in separate layers, but are preferably contained in the same layer. In an embodiment in which two or more layers made of a water-soluble polymer are laminated, any layer may contain a carboxylic acid, but it is preferable to contain it in a lower layer.

In the present invention, gelatin is particularly preferred as the water-soluble polymer as described above. The combination of gelatin and carboxylic acid can further improve ink absorbency and improve bleeding of fine lines. However, on the other hand, a combination of gelatin and 1% by weight or more of a carboxylic acid tends to cause stickiness of a printed portion. It is considered that this stickiness occurs because only the water component of the ink is selectively absorbed immediately after printing, and the solvent component of the ink is not absorbed and remains on the surface. This stickiness may further contain a water-soluble polymer other than gelatin, that is, a vinyl polymer such as polyvinyl alcohol, polyvinylpyrrolidone, or polyacrylamide, or a cellulosic polymer such as carboxymethylcellulose or hydroxypropylcellulose. Can be improved by Among these water-soluble polymers, polyvinylpyrrolidone is particularly preferred. When the content of other water-soluble polymers other than gelatin is increased, the film strength is weakened, and there is a risk of being redissolved by the ink when printing.Therefore, the content ratio of gelatin and other water-soluble polymers is by weight, Preferably between 80:20 and 20:80, more preferably between 70:30 and 40:60.

In the present invention, when gelatin is used as a polymer, a hardener may be used to impart film strength or water resistance. As the type of the hardener, an aldehyde compound, an epoxy compound, an aziridine compound, a halogen carboxy compound and the like can be used. The hardener is added in an amount of 0.01 to 10% by weight, preferably 0.1 to 5% by weight, based on gelatin.

In the present invention, a surfactant may be added to the coating solution. Any of nonionic, anionic, cationic, and betaine surfactants may be used. The amount of the surfactant added is 0.0
It is between 1% and 1% by weight, preferably between 0.1% and 0.3% by weight.

In the present invention, when a recording material for ink-jet recording is produced, as a support to be used, for example, a polyester film, a resin-coated paper, a coated paper or the like is mainly used. ,
The support is not particularly limited as long as it is a support on which an ink absorbing layer such as a vapor-deposited paper or a vapor-deposited film can be provided.

The ink-absorbing layer is provided on at least one side of the support.
It may be provided on both sides of the support.

When a polyester film is used as the support in the present invention, the thickness thereof is not particularly limited, but is preferably about 10 to 200 μm from the viewpoint of handling properties and aptitude for passing a printer.

Specific examples of the polyester include polyethylene terephthalate, polyethylene butylene terephthalate, polyethylene-2,6-naphthalate and copolymers thereof with other components, but the present invention is not limited to these. .

When a white polyester film is used as a support, as a method for increasing the whiteness of the polyester film, inorganic fine particles such as barium sulfate, titanium dioxide, calcium carbonate, silicon dioxide, aluminum oxide, kaolin and talc are used. There are a method of containing the polyester film inside the polyester film and a method of applying a white paint to the surface.

The base paper for the resin-coated paper is not particularly limited.
Generally used paper can be used, but preferably,
For example, a smooth base paper as used for a photographic support is preferable. As the pulp constituting the base paper, a natural pulp, a recycled pulp, a synthetic pulp, or the like is used alone or in combination of two or more. The base paper is blended with additives generally used in papermaking, such as a sizing agent, a paper strength enhancer, a filler, an antistatic agent, a fluorescent whitening agent, and a dye. Furthermore,
Surface sizing agent, surface paper strength agent, optical brightener, antistatic agent,
A dye, an anchoring agent or the like may be applied on the surface.

As the coating resin for the resin-coated paper, a polyolefin resin is preferable, and a polyethylene resin is particularly preferable. Further, low density polyethylene, medium density polyethylene, high density polyethylene or a mixture thereof can be used. The thickness of the coating resin layer of the resin-coated paper is not particularly limited, but is generally coated to a thickness of 5 to 50 μm only on the surface or on both the front and back surfaces.

In the resin of the resin-coated paper, white pigments such as titanium oxide, zinc oxide, talc and calcium carbonate; fatty acid amides such as stearamide and arachidic amide;
Fatty acid metal salts such as zinc stearate, calcium stearate, aluminum stearate, magnesium stearate, Irganox 1010, Irganox 1
076 or the like; an antioxidant such as cobalt blue, ultramarine blue, cecilian blue, a blue pigment or dye such as phthalocyanine blue, cobalt violet, fast violet,
Various additives such as magenta pigments and dyes such as manganese purple, fluorescent brighteners and ultraviolet absorbers can be added in appropriate combinations.

The surface (surface) of the support on which the ink absorbing layer is applied has a glossy surface, a matte surface, and the like, and a glossy surface is particularly preferably used, depending on the use. It is not always necessary to coat the back surface with a resin, but it is preferable to coat the resin from the viewpoint of curling prevention. The back is usually matte,
Corona discharge treatment on the surface or on both sides if necessary,
Activation treatment such as flame treatment can be performed.

For applying the coating liquid of the present invention to the above-mentioned substrate, conventionally known techniques such as a roller method, a gravure method, a blade method, an air knife method, a slide bead method, and a curtain method are used.

[0026]

EXAMPLES The present invention will be described below in detail with reference to examples, but the contents of the present invention are not limited to the examples.

Example 1 A low-density polyethylene (70 parts) and a high-density polyethylene (20 parts) were provided on the surface of a 100 g / m ² base paper comprising a pulp blend of LBKP (50 parts) and LBSP (50 parts).
And a titanium oxide (10 parts) resin composition at 25 g /
m ² , and a resin composition composed of high-density polyethylene (50 parts) and low-density polyethylene (50 parts) was applied to the back surface at 25 g /
Resin-coated paper coated with m ² was used. The following coating solution was coated on the support with a slide bead coater at a coating amount of 1
Immediately after the application so as to be 00 cc / m ² , it is cooled and set for 10 seconds, and then passed through the drying zone where the temperature is gradually higher, and the temperature and humidity of the drying zone are controlled so that the surface wet bulb temperature becomes 20 ° C. or less. Thus, an ink jet recording sheet was prepared. Samples were prepared in which the type of polymer, the type of carboxylic acid and the amount of addition of the following ink receiving layer coating liquid composition are shown in Table 1.

<Coating liquid composition> Pure water 800 g Polymer 100 g Carboxylic acid Xg Adjusted to a total of 1000 g with pure water

With respect to the ink jet recording sheet sample prepared as described above, the bleeding of the fine line after printing was evaluated by the following test method. Table 1 shows the results.

<Evaluation of Fine Line Bleeding> Printing was performed with GO ink (pigment ink) using a plotter Novajet PRO manufactured by ENCAD. After printing, the sheet was sufficiently dried, and evaluated by the following method. A test pattern including a pattern of fine lines of Y and M + Y was printed in a solid color solid of 300% of C + M + Y, and the visual evaluation was made to see how much the fine lines could be observed without bleeding. ◎ indicates that the thin line was clearly observable, ○ indicates that the thin line was slightly hidden, △ indicates that the thin line was barely visible, and X indicates that the ink could not be absorbed and flowed.

[0031]

[Table 1]

As is clear from Table 1, bleeding is remarkably improved by adding 1% by weight or more of carboxylic acid to the water-soluble polymer. Use of gelatin as a water-soluble polymer has a large effect, and carboxylic acid is more effective when malic acid or succinic acid, which is a dicarboxylic acid having a small number of carbon atoms, is used.

Example 2 An ink jet recording sheet was prepared using the same support and coating method as in Example 1. Samples were prepared such that the amounts of gelatin and polyvinylpyrrolidone added in the following ink receiving layer coating composition were as shown in Table 2, and the bleeding of the fine lines and the stickiness were evaluated. Table 2 shows the results.

<Coating liquid composition> Pure water 800 g Gelatin Yg Polyvinylpyrrolidone (PVP K-90, manufactured by BASF) Zg Malic acid 10 g Adjusted to a total of 1000 g with pure water

<Fine line bleeding> The same method as in Example 1 was used. <Evaluation of stickiness> Plotter Novaj manufactured by ENCAD
Printing was performed with GO ink (pigment ink) using etPRO. After printing, the sheet was sufficiently dried, and evaluated by the following method. P for C + M + Y + K 400% solid color solid printing area
Lay the PC paper and leave it for a while. Stickiness was determined based on the degree of peeling of the PPC paper and the degree of transfer of the printing portion to the PPC paper.

[0036]

[Table 2]

From the above results, it is possible to improve the tackiness without reducing bleeding by combining gelatin and other water-soluble polymers.

[0038]

As shown in Example 1, the ink absorbency was remarkably improved and no bleeding was observed. Example 2
As described above, the stickiness of the printed portion was also improved while maintaining the ink absorbency.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (reference) D21H 5/00 Z F term (reference) 2C056 EA05 FC06 2H086 BA15 BA31 BA35 4D075 CA35 DA06 DB18 DC27 EA06 EB56 4L055 AG19 AG34 AG53 AG57 AG59 AH02 AH37 AH48 AJ02 AJ04 BE09 EA32 FA12 GA09

Claims (4)

[Claims] 1. An ink jet recording sheet comprising:
An ink jet recording sheet, wherein the image receiving layer contains a water-soluble polymer and 1% by weight or more of a carboxylic acid based on the water-soluble polymer. 2. The ink jet recording sheet according to claim 1, wherein the water-soluble polymer is gelatin. 3. The ink jet recording sheet according to claim 2, further comprising another water-soluble polymer. 4. The ink jet recording sheet according to claim 1, wherein the carboxylic acid is represented by the following general formula. Embedded image In the formula, L represents a divalent linking group comprising an aliphatic group having 6 or less carbon atoms or an aromatic group.