JP2002219865A - Ink jet recording medium - Google Patents

Abstract

[PROBLEMS] To provide an ink jet recording medium having excellent light fastness, high print density and no bleeding problem. An ink jet recording medium comprising an ink receptive coating layer containing a porous pigment, an adhesive and a cationic ink fixing agent provided on at least one surface of a substrate, wherein the surface pH of the substrate is 5. 0 to 8.0, containing at least one of amorphous silica, alumina, and zeolite as the porous pigment, containing silanol-modified polyvinyl alcohol as the adhesive, and having a molecular weight as the cationic ink fixing agent. An ink jet recording medium comprising 30,000 to 250,000 polydiallyldimethylammonium chloride.

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 medium for recording using an aqueous ink, and more particularly to an ink jet recording medium excellent in ink absorbency, print density and light resistance.

[0002]

2. Description of the Related Art An ink jet recording system using an aqueous ink has a low noise at the time of recording, is easy to colorize, and is capable of high-speed recording. Applications to form printing and the like are being promoted. However, high-quality paper and coated paper used for general printing have poor ink absorbency, so the printed ink does not dry on the paper surface and remains for a long time, contaminating the equipment and continuously printed sheets. Practicality is poor because the image becomes dirty or the image becomes dirty. In order to solve such a problem, a method using a recording paper having a small size (Japanese Patent Laid-Open No. 52-53012) or a method of impregnating a base paper containing a urea-formalin resin with a water-soluble polymer (Japanese Patent Laid-Open No. 53-49113) has been proposed.

Further, recording papers coated with various porous inorganic pigments such as amorphous silica on the surface thereof for the purpose of enhancing the color developability and reproducibility of the ink (JP-A-55-51583; No. 56-148585), and the physical properties of these porous pigments are specified for the purpose of obtaining a high-definition image with reduced bleeding (JP-A-58-110287).
JP, JP-A-59-185690, JP-A-sho 61
(Japanese Patent Application Laid-Open No. 141584) has been proposed. Further, a method using a cationic ink fixing agent has also been proposed for the purpose of improving image reproducibility and water resistance, and polydiallyldimethylammonium chloride is used as a particularly excellent cationic ink fixing agent (Japanese Patent Application Laid-Open No. −
68926, JP-A-11-227316).

[0004] On the other hand, as the application range of the ink jet recording system is widened, the opportunities for exposing the recording medium to fluorescent light or sunlight are increasing, and there are many situations where light resistance, which has not been so much neglected, is required. It has become. In order to cope with such a situation, several methods for improving light resistance have been disclosed. For example, a method using an ultraviolet absorber (Japanese Patent Application Laid-Open No. 57-87988), a method using a hindered amine compound as a light fastness improver (Japanese Patent Application Laid-Open No. 61-146591), a method using a transition metal in the ink receiving layer. Method of adding ultrafine powder of a compound (Japanese Patent Laid-Open No. Hei 4-201594), resin binder 1 comprising polyvinyl alcohol and cationic water-soluble resin
A method of blending a compound having a phenolic hydroxyl group as a lightfastness improving additive in an amount of 0.1 to 30 parts by weight with respect to 00 parts by weight (JP-A-1-241487); A method in which a complex is added to an ink receiving layer (Japanese Patent Application Laid-Open No. 8-132727), a method in which magnesium sulfate having a dry adhesion amount of 0.2 to 2.0 g / m ² is adhered to a support (Japanese Patent Application Laid-Open No. 9-290)
No. 556) is disclosed.

However, the technical development of ink jet printers has been remarkable, and most of recent ink jet printers have improved dot granularity by miniaturizing ink droplets and ink per nozzle, in order to obtain high image quality comparable to silver halide photographs. In addition to improving the gradation expression by making the ejection amount variable, the gradation expression is also improved by using a new low print density ink (so-called light color ink or photo ink). It was very difficult to obtain high lightfastness for all inks. In particular, recording paper using polydiallyldimethylammonium chloride as a cationic ink fixing agent is excellent in image reproducibility and water resistance, but may be poor in light resistance depending on the type of ink.

[0006]

An object of the present invention is to use polydiallyldimethylammonium chloride as a cationic ink fixing agent, to use a substrate having a surface pH of 5 to 8, to provide excellent light fastness and to provide printing. An object of the present invention is to provide an ink jet recording medium having a high density and free from bleeding and other problems.

[0007]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above problems, and as a result, by selecting a specific material, an ink jet recording medium having remarkably improved ink jet recording characteristics and light resistance. Was obtained, and the present invention was completed. That is, the present invention
In an ink jet recording medium provided with an ink receptive coating layer containing a porous pigment, an adhesive and a cationic ink fixing agent on at least one surface of a substrate, the surface pH of the substrate is 5.0 to 8 The porous pigment contains at least one of amorphous silica, alumina, and zeolite as the porous pigment, contains silanol-modified polyvinyl alcohol as the adhesive, and has a molecular weight of 30,000 to 250,000 as the cationic ink fixing agent. An ink jet recording medium comprising: polydiallyldimethylammonium chloride. The porous pigment is preferably amorphous silica. The coating amount of the ink receptive coating layer is
A range of ^{2 to} 15 g / m ² is preferred. The content of the silanol-modified polyvinyl alcohol is preferably 10 to 50 parts by weight based on 100 parts by weight of the amorphous silica.
The content of the polydiallyldimethylammonium chloride is preferably 5 to 30 parts by weight based on 100 parts by weight of the amorphous silica. The base material is a paper base material having a pulp and a filler, the proportion of softwood pulp is 60% by weight or less in the whole pulp, and the filler is zeolite, silica,
It is preferably at least one selected from calcium carbonate and calcined kaolin. It is preferred that the substrate has a Stockigt sizing degree (JIS P8112) of 40 seconds or less.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The substrate used in the present invention is not particularly limited, and synthetic papers, films, laminated papers and the like can be used in addition to papers mainly composed of cellulose pulp. Above all, papers containing cellulose pulp as a main component are preferable because they are excellent in ink absorbency and cost.

The pulp component of the paper used as the base material of the present invention includes chemical pulp such as bleached softwood kraft pulp and bleached hardwood kraft pulp, mechanical pulp such as GP, BCTMP and MP, and non-wood raw material such as kenaf. Papermaking pulp represented by the obtained pulp and the like can be mentioned, and these can be used in combination. Although the kind of wood is not particularly limited, since a high blend of softwood (N wood) may induce feathering, the blending ratio of softwood (N wood) should be 60% or less of the total pulp component. Is preferred.

It is also possible to use waste paper pulp as the pulp. The raw material of the waste paper pulp is not particularly limited, and may be used newspaper, used printing paper, used corrugated cardboard,
Arbitrary waste paper such as wrapping paper, office waste paper and the like can be used. The method for obtaining recycled pulp from waste paper is not particularly limited, but in general, a defibration step of defibrating waste paper to obtain a pulp suspension, a rough selection for separating foreign substances in the pulp suspension, and a fine selection The recycled pulping is performed through a process, a deinking process for separating printing ink, and a bleaching process for whitening the color. In addition, waste paper that has not been subjected to printing, etc. as a raw material,
It is also possible to use disintegrated pulp that does not require a deinking process.

Freeness of pulp is 200-550ml
Is preferred. If the freeness exceeds 550 ml, the uniformity of the paper may deteriorate, and the uniformity of ink jet recording may be impaired. On the other hand, if the freeness is less than 200 ml, bleeding may be deteriorated.

The filler to be internally added is zeolite, silica such as amorphous silica, calcined kaolin, talc, kaolin, calcium carbonate, white carbon, diatomaceous earth, titanium oxide,
At least one selected from inorganic pigments such as activated clay and barium sulfate, and organic pigments such as urea formalin resin, nylon powder and polyethylene powder can be used. Preferably, it is zeolite, silica, calcined kaolin or calcium carbonate. The compounding amount of the filler is 1 to 30% by weight, preferably 5 to 25% by weight based on the whole pulp. If it is less than 1% by weight, bleeding may worsen,
If it exceeds 30% by weight, the print density may be reduced.

[0013] The base paper of the present invention is made of polyolefin fibers such as polyethylene, polypropylene, ethylene-propylene copolymer, polystyrene, ethylene-vinyl acetate copolymer, halogen-containing polymers such as polyvinyl chloride, polyvinylidene chloride, etc. -Polyamide fibers such as nylon and 6,6-nylon, polyethylene succinate, polycaprolactone, polylactic acid, polyhydroxybutyrate.
An aliphatic polyester fiber such as a valerate copolymer, a vinylon fiber, or the like may be contained.

The base paper of the present invention can be prepared by an ordinary method using an acidic or neutral paper. If necessary, a yield improving agent such as a sulfuric acid band can be used. Further, sizing agents represented by rosin-based sizing agents, alkenyl succinic anhydrides, alkyl ketene dimers, etc., starches such as oxidized starch, enzyme-modified starch, cation-modified starch, esterified starch, etherified starch, methylcellulose, ethylcellulose , Carboxymethylcellulose, methoxycellulose, hydroxycellulose, completely or partially saponified polyvinyl alcohol, carboxy-modified polyvinyl alcohol, polyvinyl alcohols such as silicon-modified polyvinyl alcohol, polyacrylamide, polyvinylpyrrolidone, acrylic acid amide-acrylate copolymer, Acrylic acid amide / acrylic ester / methacrylic acid copolymer, styrene / maleic anhydride copolymer alkali salt, isobutylene / maleic anhydride copolymer alkali salt, Water-soluble polymers zein etc., polyvinyl acetate, polyurethane, polyacrylic acid,
Polyacrylate, polybutyl methacrylate,
An adhesive represented by a latex such as a styrene / butadiene copolymer, a vinyl chloride / vinyl acetate copolymer, and a styrene / butadiene / acrylic copolymer may be contained.

The papermaking method is not particularly limited.
Paper is made using a fourdrinier machine, a round net machine, a twin-wire machine, or the like. Degree of Sekihito size of base paper (JIS
P8122) is preferably 40 seconds or less. By setting the time to 40 seconds or less, bleeding can be effectively prevented.

Although the tension of the base paper is not particularly limited, it is preferably 0.5 to 1.2 g / cm ³ .
If it is less than 0.5 g / cm ³ , the transportability may be deteriorated, and if it exceeds 1.2 g / cm ³ , bleeding may be worsened.

The method for adjusting the surface pH of the base paper to 5.0 to 8.0 is not particularly limited, but the surface pH is adjusted to 5.0 by controlling the pH of the filler used and the amount of the sulfate band added. ８8.0. Further, by controlling the pH of the material included in the externally added size, the surface pH is adjusted to 5.0.
It is also possible to set it to 8.0. The surface pH is
It can be measured using a paper surface measurement PH meter Model MPC manufactured by Kyoritsu Riken.

As the porous pigment used in the ink-receiving coating layer of the present invention, at least one of amorphous silica, alumina and zeolite is preferable, and amorphous silica is particularly preferable. The structure of the amorphous silica is not particularly limited, but preferably has a porous structure obtained by manufacturing via xerogel because of easy control of ink receptivity. Further, a xerogel-based porous pigment other than silica can be used in combination.
The xerogel-based porous pigment includes, for example, (1) a hydrogel-forming substance such as aluminum hydroxide, alumina, or magnesium oxide as a raw material in addition to silica, and drying such hydrogel to form a xerogel, followed by pulverization and classification. Method to use. (2) In the state of a hydrogel, granules are formed into appropriate secondary and tertiary agglomerates, dried, and further heated to promote sintering, crystallization, etc., so that the oxide primary particles Method to strengthen the use of (3) At the stage of producing urea-formalin resin, melamine-formalin resin, etc. in a suspension of fine particles such as colloidal silica, colloidal alumina, etc., the production conditions are adjusted to produce the desired secondary particle diameter. A method in which, after being formed into fine particles, they are dried and then used as sintered particles if necessary. And the like, and are commercially available.

The pigment contained in the ink-receiving coating layer may be, for example, calcium carbonate, kaolin, talc, calcium sulfate, barium sulfate, titanium dioxide, zinc oxide, or carbon dioxide, if necessary, in addition to the xerogel-based porous pigment. Inorganic pigments such as zinc, satin white, aluminum silicate, diatomaceous earth, calcium silicate, magnesium silicate, white carbon, alumina, aluminum hydroxide, etc., and organic pigments of styrene, acrylic, urea resin, melamine resin, and benzoguanamine resin Can also be used in combination.

The adhesive used in the ink-receptive coating layer of the present invention includes starch and its derivatives, natural or semi-synthetic polymers such as carboxymethylcellulose, hydroxyethylcellulose, casein, gelatin, soybean protein, polyvinyl alcohol and the like. Derivatives, polyvinyl butyral resin, polyethylene imine resin, polyvinyl pyrrolidone resin, poly (meth) acrylic acid resin, acrylate ester resin, polyamide resin, polyacrylamide resin, polyester resin, urea resin, melamine resin, styrene An aqueous or aqueous dispersion of a vinyl copolymer resin such as butadiene copolymer, methyl methacrylate-butadiene copolymer, ethylene-vinyl acetate copolymer, or an anionic or cationic residue on the above resins To Known material such as off to modified polymer can be used as appropriate. Above all, silanol-modified polyvinyl alcohol is preferable because a high coating film strength can be obtained.

Further, for the purpose of improving the water resistance of a printed image with an aqueous ink, a polyethyleneimine resin, a polyamine resin, a polyamide resin, a polyamide epichlorohydrin resin, a polyamine epichlorohydrin resin, a polyamide polyamine epichlorohydrin resin,
Cationic resins such as polydiallylamine-based resins and dicyandiamide condensates can also be used in combination.

If necessary, a pigment dispersant, a thickener,
Antifoaming agents, foam inhibitors, foaming agents, release agents, penetrants, wetting agents, thermal gelling agents, lubricants, dyes, optical brighteners, and various other auxiliaries known in the art may also be used. it can.

The ink receptive coating layer may be composed of two or more layers for the purpose of preventing the recording medium after printing from being uneven or wavy, so-called cockling. It is preferable to use a xerogel-based porous pigment and a non-xerogel-based pigment together in the coating layer close to the support.

Means for applying the ink receptive coating layer include commonly used coatings such as a size press, a gate roll, a roll coater, a bar coater, an air knife coater, a rod blade coater, a blade coater, a die coater, and a curtain coater. It can be appropriately selected from the construction means.

[0025] Although the coating weight can be determined depending on the recording quality seeking, 2 g / ^{m 2} or more and 15 g / ^{m 2} or less. If it is less than 2 g / m ² , the ink jet recording quality may be insufficient, and may be 15 g / m ^2.
If it exceeds, the print density may be insufficient. Degree of Stekhito sizing of ink jet recording medium (JIS P812
2) is preferably 40 seconds or less. In the case of 40 seconds or more, when the ink application amount of the printer is large (for example, the ink application amount 2
0 to 40 g / m ² ), the bleeding may be worsened.

After coating, it is preferable to carry out a super calender treatment for the purpose of improving image reproducibility and transportability.

[0027]

The present invention will be described in more detail with reference to the following examples, but it should be understood that the present invention is by no means restricted to these examples. In the examples, parts and% mean parts by weight and% by weight, respectively. The methods for measuring various physical properties in the examples are shown below.

(1) Print density Ink jet printer PM- manufactured by Seiko Epson Corporation
Printing was performed at a recording density of 720 dpi using 700C, and the print density was measured (the amount of ink applied was about 30 g / m
² ). As a result, those which exhibited excellent print density were ranked A, those which were slightly thin but had no practical problems, and those which were too thin to withstand practical use were ranked C.

(2) Bleed Bleed was evaluated to evaluate the ink absorbency. Seiko Epson Inkjet Printer PM-70
200% density printing was performed at 720 dpi recording density using 0C, and the bleeding state of adjacent portions of different colors was visually evaluated. As a result, those with little bleeding were rated A, those with some bleeding but no practical problem were rated B, and those with too much bleeding and were not practical.

(3) Lightfastness An image of ISO-400 (“High-definition color digital standard image data ISO / JIS-SCD” image name: Fruit basket issued by the Japan Standards Association) is used for an inkjet printer PM- manufactured by Seiko Epson Corporation. Printing at a recording density of 720 dpi using 700C, a xenon lamp type F
ADE-OMETER (ATLAS ELECTRIC
DEVICES Co. Model: C135
Using F), print samples were prepared at 63 ° C and 50% for 24 hours.
It was processed continuously for hours. The processed image was compared with the unprocessed image. A for which almost no fading was observed, B for a case where slight fading was observed but there was no practical problem, and C for a case where remarkably fading was not practical. And ranked.

Example 1 (1) Production of base paper A preparation liquid having the following composition was hand-made according to the method for preparing hand-made paper according to JIS P8222, and a Stockigt size of 10 seconds was prepared.
A base paper having a strength of 0.8 g / cm ³ was obtained. Pulp (LBK
P, 100 ml of freeness, 100 parts, zeolite (Tixolox 17, manufactured by RHODIA KOFRAN),
Oil absorption 150 ml / 100 g) 10 parts (prepared to be 10% of the total pulp in the manufactured paper), acid rosin size 0.5 part, sulfuric acid band 1.5 parts. The surface pH of the obtained base paper was 5.5. The measurement was carried out using a pH meter model MPC manufactured by Kyoritsu Riken Co., Ltd.
It was measured in the environment of 50 ° C. and 50% RH according to the method described in the PH meter. However, the drying time of the test solution was set to 2 seconds after the test solution was spread.

(2) Production of Inkjet Recording Medium A coating liquid for an ink receptive coating layer having the following composition was applied to one surface of the obtained base paper so that the coating amount after drying was 7 g / m ^2. After applying and drying using, a super calendar treatment was performed to obtain an ink jet recording medium. 100 parts of xerogel type porous amorphous silica (Fine Seal X-60, manufactured by Tokuyama), 20 parts of silanol-modified polyvinyl alcohol (R-1130, manufactured by Kuraray), 5 parts of SBR latex (JSR0617, manufactured by Asahi Kasei), Polydiallyl dimethyl ammonium chloride (molecular weight 5000
0, CP-102, manufactured by Senka) 5 parts

Example 2 An ink jet recording medium was obtained in the same manner as in Example 1.
However, in the production of base paper, silica (Tokusil GU-N, manufactured by Tokuyama, oil absorption 190 to 240 ml / 100 g) was used instead of zeolite as a filler. The Stockecht sizing degree of the base paper was 8 seconds, and the surface pH was 5.5.

Example 3 An ink jet recording paper was obtained in the same manner as in Example 1. However, in the production of base paper, calcium carbonate (Softon 2200, manufactured by Shiraishi Calcium Co., oil absorption 38/100 g) is used instead of zeolite as filler, and 0.5 parts of neutral rosin size is used instead of acid rosin size. Then, the added amount of the sulfuric acid band was 0.3 parts. The Stockecht sizing degree of the base paper was 11 seconds, and the surface pH was 6.0.

Example 4 An ink jet recording medium was obtained in the same manner as in Example 1.
However, in the production of base paper, an externally added starch size was applied. A 2% aqueous solution of Oji Ace A (manufactured by Oji Constarch) was used as an externally added starch-size paint, and the coating was dried using a Meyer bar so that the coating amount after drying was 1 g / m ^{2 on} both sides. The base paper size of the Stekicht is 13
Seconds, the surface pH was 5.5.

Example 5 An ink jet recording medium was obtained in the same manner as in Example 1.
However, in the production of the ink jet recording medium, Carplex FPS-101 (manufactured by Shionogi Pharmaceutical Co., Ltd.) instead of Fine Seal X-60 (manufactured by Tokuyama Co., Ltd.) was used as the xerogel-based porous amorphous silica of the receptive coating layer. Was used.

Example 6 An ink jet recording medium was obtained in the same manner as in Example 1.
However, in the production of an ink jet recording medium, polydiallyldimethylammonium chloride (CP-10
2. Polydiallyldimethylammonium chloride (molecular weight 100,000, Unisense CP-103, manufactured by SENKA) was used instead of (2, manufactured by SENKA).

Example 7 An ink jet recording paper was obtained in the same manner as in Example 1. However, in the production of the ink jet recording medium, the coating amount was 4 g / m ² .

Example 8 An ink jet recording medium was obtained in the same manner as in Example 1.
However, in the production of an ink jet recording medium, polydiallyldimethylammonium chloride (CP-10
2. Polydiallyldimethylammonium chloride (molecular weight: 200,000, Unisense CP-104, manufactured by SENKA) was used instead of (2, manufactured by SENKA).

Comparative Example 1 An ink jet recording medium was obtained in the same manner as in Example 1.
However, in the production of the base paper, the added amount of the sulfuric acid band was 2 parts. The base paper Stekigt sizing degree is 11 seconds, surface pH
Was 3.0.

Comparative Example 2 An ink jet recording medium was obtained in the same manner as in Comparative Example 1.
However, in the production of base paper, an externally added starch size was applied. A 2% aqueous solution of Oji Ace A (manufactured by Oji Constarch) was used as an externally added starch-size paint, and the coating was dried using a Meyer bar so that the coating amount after drying was 1 g / m ^{2 on} both sides. Base paper Stekihito sizing degree is 12
Seconds, the surface pH was 3.0.

Comparative Example 3 An ink jet recording medium was obtained in the same manner as in Comparative Example 1.
However, in the production of base paper, silica (Tokusil GU-N, manufactured by Tokuyama, oil absorption 190
２４０240 ml / 100 g). The Stockecht sizing degree of the base paper was 11 seconds, and the surface pH was 3.0.

Comparative Example 4 An ink jet recording medium was obtained in the same manner as in Comparative Example 1.
However, in the production of an ink jet recording medium, polydiallyldimethylammonium chloride (CP-10
Acrylamide / diallylamine copolymer (Sumilez Resin 1001, manufactured by Sumitomo Chemical Co., Ltd.) was used in place of (Senka Co., Ltd.), and the coating amount was 1.5 g / m ² .

Comparative Example 5 An ink jet recording medium was obtained in the same manner as in Comparative Example 1.
However, in the production of an ink jet recording medium, polydiallyldimethylammonium chloride (CP-10
2. Polydiallyldimethylammonium chloride (molecular weight: 20,000, Unisense CP-101, manufactured by SENKA) was used instead of (2, manufactured by SENKA).

Comparative Example 6 An ink jet recording medium was obtained in the same manner as in Comparative Example 1.
However, in the production of an ink jet recording medium, polydiallyldimethylammonium chloride (CP-10
2. Polydiallyldimethylammonium chloride (molecular weight: 500,000, Unisense CP-105, manufactured by SENKA) was used instead of (2, manufactured by SENKA).

Table 1 shows the results of evaluating the recording density, bleeding, and light fastness of the above 14 types of ink jet recording media.

[0047]

[Table 1]

[0048]

As is clear from Table 1, the examples of the present invention were excellent in print density, print bleeding, and light resistance in all of the ink jet recording media as compared with the comparative examples.

Claims (4)

[Claims] 1. A porous pigment on at least one surface of a substrate,
In an ink jet recording medium provided with an ink receptive coating layer containing an adhesive and a cationic ink fixing agent, the substrate has a surface pH of 5.0 to 8.0, and the porous pigment is an amorphous pigment. It contains at least one of porous silica, alumina and zeolite, contains silanol-modified polyvinyl alcohol as the adhesive, and contains polydiallyldimethylammonium chloride having a molecular weight of 30,000 to 250,000 as the cationic ink fixing agent. Inkjet recording medium. 2. The content of the silanol-modified polyvinyl alcohol is 10 to 50 parts by weight based on 100 parts by weight of the amorphous silica.
2. The ink jet recording medium according to claim 1, which is in parts by weight. 3. The ink jet recording medium according to claim 1, wherein the content of the polydiallyldimethylammonium chloride is 5 to 30 parts by weight based on 100 parts by weight of the amorphous silica. 4. The base material is a paper base material having pulp and filler, wherein the proportion of softwood pulp is not more than 60% by weight in the whole pulp, and the filler is selected from zeolite, silica, calcium carbonate, and calcined kaolin. Is at least one of the following, and the degree of Sechigt sizing of the substrate (JIS P811
The inkjet recording medium according to any one of claims 1 to 3, wherein 2) is 40 seconds or less.