JPH09314985A - Ink jet recording paper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain recording paper suitable for use in both ink jet and electrophotographic method by applying coating liquid containing an alumina hydrate, a chelating agent, and a cationic substance as in effective components on the support body to be a predetermined value or less in terms of at dry weight. SOLUTION: On the support body surface, applied is coating liquid containing an alumina hydrate, an chelating agent, and a cationic substance as effective components in a manner that it is to be 20g/m<2> less in terms of weight. A water dispersion liquid of 300g prepared by an 18 pts. alumina hydrate, 9 pts. imidazolium compound, 6 pts. ethylenediamine-tetraacetic acid sodium, 17.6 pts. polyacrylamide, and 249.4 pts. water is stirred by a stirrer for 30min. After that, it is dispersed for 30min by TK homomixer at 8,000rpm to obtain coating liquid. The coating liquid is taken out by means of a dropping pipet while being stirred to subsequently be coated and dried on a base weight of 80g/m<2> , 56sec Steckigt sizing degree, 100μm thickness, and 81.2% brightness by Hunter.

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 sheet for recording using ink, and more specifically, it has excellent ink absorbency, high density and sharpness of recorded image, The present invention relates to an inkjet recording sheet having excellent water resistance.

[0002]

2. Description of the Related Art Ink jet recording methods include various ink (recording liquid) ejection methods, for example, an electrostatic suction method, a method of applying mechanical vibration or displacement to ink by using a piezoelectric element,
By using a method that heats and foams the ink and uses its pressure, small droplets of the ink are generated and ejected,
Alternatively, all of the recording is performed by adhering it to a recording material such as paper, but it is attracting attention as a recording method that can perform high-speed printing and multicolor printing with less noise.

An image formed by the multicolor ink jet system can obtain a print comparable to that of the multicolor printing by the plate making system or the printing by the color photographic system. When the number of copies is small, Since it is cheaper than ordinary multicolor printing and printing, it is being widely applied to the field of full-color image recording. Although the recording apparatus and recording method have been improved along with the improvement of recording characteristics such as high-speed recording, high definition, and full-color recording, high-level characteristics are also required for recording paper. Came.

Various recording papers have been proposed so far in order to satisfy the required characteristics. For example, JP-A-55-
Japanese Patent Laid-Open No. 5830 discloses an ink jet recording paper having a support surface provided with an ink absorbing coating layer.
JP-A-55-14678 discloses an example in which amorphous silica is used as a pigment in a coating layer.
No. 6 discloses an example using a water-soluble polymer coating layer.

However, these conventional ink jet recording papers have the following drawbacks as compared with commercially available high-quality papers generally called plain papers. (1) There is a sticky feeling peculiar to the resin coming from the coating layer, and the texture of the paper is not present. (2) Since the base paper as the base material is expensive and a coating process is required, the manufacturing cost is high and the cost cannot be low. (3) When ink jet recording is performed on a recording sheet, the coating layer is peeled off due to a mechanical frictional force between the recording sheet and the sheet feeding portion of the recording apparatus, so-called powder drop occurs. Further, if the coating layer component thus generated adheres to the head of the inkjet recording apparatus, it may cause clogging of the nozzles of the head. (4) When recording is performed on a recording sheet with an electrophotographic copying machine, the same powder drop as described above occurs, and the recording apparatus is contaminated. Further, when the recording paper is passed through the fixing device for fixing the electrophotographic toner, the coat layer is heat-fused to the surface of the fixing roller, which causes jamming and contamination of the fixing device. (5) Defects such as cracks are easily generated on the surface of the coating layer, and the image quality is degraded. (6) Curling occurs due to the difference in shrinkage between the coating layer and the base material, which is troublesome to handle, and the amount of curling changes due to changes in temperature and humidity, resulting in lack of environmental stability. (7) When writing with a normal writing tool such as a pencil or a ballpoint pen, the coating layer is scraped off, and writing cannot be performed normally.

On the other hand, when plain paper for a general copying machine is used as it is as an ink jet recording paper, it has the following drawbacks. (1) When the ink that has not been received and overflows because it has a low ink receptivity, it is smeared with other objects and stains, tailing and the like, and the color development is insufficient, the image quality is extremely low. (2) After the ink adheres to the recording paper, a whisker-like thing (feathering) occurs around the print dot, resulting in a dot having extremely low circularity. (3) Since the ink is water-soluble, the water resistance after printing on the recording paper is remarkably poor, and the image quality is deteriorated due to the bleeding of the ink due to the adhesion of water, the occurrence of flow, and the like.

Therefore, there is a demand for a recording paper which has a texture similar to that of plain paper and which has high color developability and which is excellent in water resistance.

Among these attempts, the recording paper described in JP-A-52-74340 is particularly excellent. This is a non-coated paper with a large porosity, the ink fixability is improved compared to conventional plain paper, and it does not have the drawbacks found in coated paper, but compared to inkjet coated paper, the quality of recorded matter is much higher. Inferior.

As described above, it is the current situation that a recording paper which has a coloring property comparable to that of coated paper, is excellent in water resistance, and has a texture equivalent to that of plain paper has not yet been obtained.

Further, conventionally, in the papermaking of special purpose paper which requires specific electric characteristics, for example, insulating paper, conductive metal ions in the paper forming material are sequestered by using a sequestering agent (chelating agent). It is known to do.

Further, Japanese Patent Laid-Open No. 63-211397 discloses a method for making a neutral paper from a neutral aqueous slurry containing pulp and a chelating agent for the purpose of improving the paper making yield.

However, it has been known at all that a recording paper containing a chelating agent on the surface and inside thereof enhances the color developability of a printed matter of ink jet recording by applying the chelating agent to a support. There wasn't.

[0013]

SUMMARY OF THE INVENTION The object of the present invention is to solve the above-mentioned problems of the prior art, to have rapid ink absorbability, and in particular to have excellent color developability, image density and water resistance of image. An object of the present invention is to provide an inkjet recording sheet and a recording sheet that can be commonly used in a general electrophotographic copying machine.

[0014]

The above objects can be achieved by the following means.

That is, in the present invention, a coating liquid containing an alumina hydrate, a chelating agent and a cationic substance as active ingredients is coated on the surface of a support so that the dry weight is 20 g / m ² or less, and the support is obtained. The present invention proposes an inkjet recording paper characterized in that an active ingredient of the coating liquid is present on the body surface and inside thereof, wherein the pH of the chelating agent is 7 or more, and the chelating agent is ethylenediamine. Tetraacetic acid (EDTA), hydroxyethylethylenediaminetriacetic acid (HEDTA), hydroxyethylethylenediaminediacetic acid (DHEDDA), 1,3 propanediaminetetraacetic acid (1,3PDTA), diethylenetriaminepentaacetic acid (DTPA), triethylenetetraminehexaacetic acid ( TTHA), nitrilotriacetic acid (NTA), gluconic acid, dihydroxyethyl At least one selected from glycine (DHEG), hydroxyethyliminodiacetic acid (HIMDA, HIDA), uramyldiacetic acid (VDA), dimethylglyoxime, phytic acid, water-soluble salts of the above acids, and potassium sodium tartrate. The hydrated alumina is pseudo-boehmite, the cationic substance is quaternary ammonium, the cationic substance is a benzalkonium compound, and the cationic substance is an imidazolium compound. Including that.

Hereinafter, the present invention will be described in more detail.

First, as the support to be applied in the present invention, suitable sized paper having a basis weight of 50 to 120 g / m ² or non-sized paper can be used without particular limitation.

Next, it is added to the coating liquid used in the present invention.
The alumina hydrate used is an Iwayu which is amorphous in X-ray.
Those obtained from amorphous alumina hydrate are preferable.
Among them, amorphous alumina preferably used in the present invention
The hydrate initially has a particle size of 20 to 30 angstroms.
Strom, whose composition is Al_Two O_Three ・ 3H_Two O chemical
Cα amorphous, which is unstable to water and easily dissolves in acids and alkalis
A gel is generated, and / or in a neutral or weak alkaline aqueous solution.
Or it changes into Cβ gel by heating, and boehmite gel
Is called Al and its composition is Al_Two O_Three ・ 1.0 to 2.0H_Two 
It is considered to be O and is clearly different from crystalline boehmite.
Become. The X-ray diffraction pattern has a larger half-value width than crystalline boehmite.
It is called pseudo-boehmite. Also, pseudo-boehmite
Is a compound with low crystallinity, such as Rosek et al. (Collec
t. Czech. Chem. Commun. , Volume 56,
1253-1262, 1991), the composition is A
l _Two O_Three ・ XH_Two Considered to be O (1.0 <x <2.0)
available.

A typical example of this pseudo-boehmite is the alumina hydrate A described in the example of JP-A-7-89221. This alumina hydrate A was first manufactured into aluminum alkoxide by the method described in US Pat. No. 4,242,271, and the aluminum alkoxide was hydrolyzed by the method described in US Pat. No. 4,202,870. Disassemble and oven 30 ℃,
After aging for 2 hours, a colloidal sol of alumina is obtained.
Alumina hydrate A is obtained by spray drying this colloidal sol at 75 ° C. This alumina hydrate A is amorphous and has a flat plate shape, and has a BET specific surface area of 76 g / m ² , B
The ET pore volume is 0.57 cc / g.

The reason why such pseudo-boehmite has a high ink receptivity is considered to be due to the fact that its pore radius and pore size distribution are in a range very suitable for ink receptivity. The pore size distribution of pseudo-boehmite has two or more maximums. The solvent component in the ink is absorbed by the relatively large pores, and the dye in the ink is adsorbed by the relatively small pores. One of the maximum pore size distributions of pseudo-boehmite is 100
It is preferably angstrom or less, more preferably 10
~ 60 angstroms. The other maximum is a pore radius of 1
The range from 00 to 200 Angstroms is preferred.

In the recording medium using these alumina hydrates, since the alumina hydrate has a positive charge, the ink dye having a negative charge can be well fixed and an image with good color development can be obtained. Conventionally, there are no problems such as brown discoloration of black ink, light resistance, etc., which have been caused by using a silica compound in the past, and further, it is preferable compared to conventional recording media in terms of image quality, especially in full color image. is there.

On the other hand, so-called plain paper used in general copying machines and conventional ink jet coated paper contain clay, talc, calcium carbonate, kaolin and the like as inorganic fillers, and these are alumina. Ink receptivity is low because it has no pore radius and pore size distribution suitable for ink reception such as hydrate (pseudo-boehmite). Further, since these fillers do not have a positive charge or have a negative charge, fixing of the ink dye having a negative charge is not sufficient and only an image having low color developability can be obtained.

The addition amount of the alumina hydrate and the alumina hydrate containing a metal oxide other than alumina in the coating liquid used in the present invention is preferably 3 to 15% by weight based on the weight of the coating liquid.

The alumina hydrate used in the present invention may be one containing a metal oxide, for example, titanium dioxide, and has a dispersibility and adsorption of a dye in an ink which have been difficult to achieve in the past. Both properties can be further improved over conventional alumina hydrates.

The content ratio of titanium dioxide is preferably 0.01 to 1.00% by weight of the alumina hydrate, more preferably 0.13 to 1.00% by weight. Further, the titanium dioxide preferably has a titanium valence of +4.

As metal oxides other than titanium dioxide,
Oxidation of magnesium, calcium, strontium, barium, zinc, boron, silicon, germanium, tin, lead, zirconium, indium, phosphorus, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, manganese, iron, cobalt, nickel, ruthenium, etc. Although it can be used by containing a substance, titanium dioxide is most preferable from the viewpoint of the adsorption and dispersibility of the ink dye. Many of the above metal oxides are colored, but titanium dioxide is colorless, which is also preferable.

Next, chelating agents used in the present invention include ethylenediaminetetraacetic acid (EDTA), hydroxyethylethylenediaminetriacetic acid (HEDTA), hydroxyethylethylenediaminediacetic acid (DHEDDA),
1,3 Propanediaminetetraacetic acid (1,3PDTA), Diethylenetriaminepentaacetic acid (DTPA), Triethylenetetraminehexaacetic acid (TTHA), Nitrilotriacetic acid (NT
A), gluconic acid, dihydroxyethylglycine (DH
EG), hydroxyethyliminodiacetic acid (HIMDA,
HIDA), uramyl diacetic acid (VDA), dimethylglyoxime, phytic acid, water-soluble salts of the above acids, and at least one selected from potassium sodium tartrate. Among such chelating agents, p
Alkaline having H of 7 or more, especially pH of 9 to 13,
If a more specific substance name is selected from the above-listed substances and used, a better color developability is surely obtained.
The pH of the chelating agent is a value when the pH of a saturated aqueous solution of the chelating agent is measured.

The coloring property of ink jet recording which is enhanced by the chelating agent means the image density where the yellow, magenta, cyan and black colors are in the image and the sharpness showing the vividness of the color. It is a comprehensive performance and one of the most important performances in inkjet recording.

In the method of the present invention, the reason why the chelating agent has the effect of enhancing the coloring property of the recording paper for ink jet recording is not yet clear. However, considering that the dye ion of the dye of the inkjet ink is an anion and the counter ion is a metal ion, and that the ink contains metal ions such as Ca, Mg and Si as impurities, these are usually used. A metal ion is involved in the dye ion in some form, and by blocking such a metal ion with a chelating agent (sequestering agent), the ionization tendency of the dye is enhanced and the coloring function is promoted. it is conceivable that.

Regarding the type and amount of the chelating agent used in the present invention, the type and amount of the various additives contained in the coating liquid are properly taken into consideration as long as they exhibit desired effects. Can be specified.

The amount of the chelating agent added to the coating liquid is preferably 0.1 to 10% by weight, more preferably 0.5 to 7% by weight, based on the weight of the coating liquid. If the addition amount is less than 0.1% by weight, the sufficient effect of improving the color developability cannot be obtained, and even if the addition amount is more than 10% by weight, the effect is no longer improved.

The chelating agent is effective when added before, during, or after the dispersion of the alumina pigment.

When the alumina pigment and the chelating agent are mixed to cause coagulation and precipitation, which causes troubles during coating, the coating solution is changed to a dispersion containing the alumina pigment and an aqueous solution containing the chelating agent. After dividing and coating one liquid, the other liquid may be coated on the same surface. At this time, the order of coating may be either first (undercoating) and either later (topcoating), but in order to keep the effect of improving color development at a higher level, use an alumina pigment. It is preferable to apply the dispersion containing liquid first, and then apply the aqueous solution containing the chelating agent on the same surface. Further, the number of times of coating is not limited to this, and it is also possible to apply a large number of times of 3 or more.

The recording paper of the present invention contains a cationic substance as a waterproofing agent in order to improve the water resistance after recording by ink jet. The term "cationic substance" as used in the present invention refers to a substance that dissociates and exhibits a cationic property when dissolved in water, and corresponds to an organic substance such as a quaternary ammonium monomer or polymer, or an inorganic substance such as a metal salt. It is considered that when ink-jet recording is performed on a paper coated and impregnated with this cationic substance, the dye of the printed ink reacts with the cationic substance to enhance the water resistance of the dye. That is, the ink-jet ink is usually a water-soluble dye and has an anionic property, and the cationic substance contained in the recording paper and the dye in the ink electrically react to become insoluble and bleed when water adheres. It is thought that no flow will occur.

Further, it is preferable to use organic quaternary ammonium as the cationic substance. Fourth in the present invention
The quaternary ammonium is any one of a monomer, an oligomer and a polymer having a quaternary ammonium group, or a condensate or polymer thereof, and dissociates to exhibit a cationic property when dissolved in water. The quaternary ammonium reacts more strongly with the dye in the ink as compared with an inorganic cationic substance such as a metal salt, and can further improve the water resistance of the inkjet recorded image.

The quaternary ammonium which can be applied to the present invention is not particularly limited as long as it is a substance having a quaternary ammonium group, and specifically, benzalkonium compounds, imidazolium compounds, polyamines, Polyamine sulfone, polyamide, polyamidoamine, polyethyleneimine, polyamide epichlorohydrin, polyallylamine, dicyandiamide cationic resin, dimethyldiallylammonium, cationic cellulose, cationic modified polyvinyl alcohol, cationic surfactant, simple substance such as cationic polyacrylamide, Mixtures, derivatives, condensates and the like are included. Among these specific examples, monomers such as benzalkonium compounds and imidazolium compounds are more preferable. Compared to other quaternary ammonium and cationic polymers, these enhance the water resistance of the ink jet recorded image, obtain an image with more excellent color developability, and have a lower viscosity than the polymer and easy coating. The points are excellent.

The amount of these cationic substances added is preferably 0.1 to 15% by weight in the coating solution, and is 0.5.
More preferably, it is from 10% by weight. If the addition amount of the cationic substance in the coating liquid is less than 0.1% by weight, the water resistance effect is not sufficiently obtained, and if it exceeds 10% by weight, the effect of further improving the water resistance is recognized. Absent.

The cationic substance can be used by dissolving it in a coating solution and coating it on a base paper to allow it to penetrate not only to the surface of the paper but also to some extent inside to obtain a recording paper.

The coating liquid preferably contains a binder, if necessary. As the binder, for example, polyacrylic amide, polyvinyl alcohol, vinyl acetate, oxidized starch, etherified starch, cellulose derivatives such as carboxymethyl cellulose, hydroxyethyl cellulose, casein, gelatin, soybean protein, silyl modified polyvinyl alcohol, etc .; maleic anhydride resin, Styrene
Conjugated diene-based copolymer latex such as butadiene copolymer and methylmethacrylate-butadiene copolymer; acrylic-based polymer latex such as polymer or copolymer of acrylic acid ester and methacrylic acid ester; ethylene-vinyl acetate copolymer Or other vinyl-based polymer latex; or functional group-modified polymer latex with a functional group-containing monomer such as carboxyl group of these various polymers; water-based binder such as thermosetting synthetic resin system such as melamine resin or urea resin; Synthetic resin binders such as polymethylmethacrylate, polyurethane resins, unsaturated polyester resins, vinyl chloride-vinyl acetate copolymers, polyvinyl butyral, and alkyd resins are mentioned, and they are used in one kind or more.
Of these, water-soluble polymer binders are preferably used in the present invention.

The addition amount of the binder in the coating liquid is preferably 0.1% by weight to 5% by weight.

As the inorganic filler in the coating liquid, for example, kaolin, clay, calcium carbonate, magnesium carbonate, talc, baryta, zinc white, titanium, magnesium hydroxide, chalk, silicates and the like can be used. These inorganic fillers may be used alone or in combination of two or more. The amount of addition is preferably 0.2% by weight to 10% by weight in the coating liquid.

Further, if necessary, a pigment dispersant, a thickener,
The flow modifier, the defoaming agent, the foam suppressor, the release agent, the colorant and the like may be appropriately blended as long as the characteristics are not impaired.

Water is preferably used as the dispersion solvent for the coating liquid, and if necessary, water may be added to polyhydric alcohols such as glycerin and ethylene glycol and their derivatives, alcohols, nitrogen such as diethyllamine, DMSO and acetonitrile. A mixture of compounds and the like is preferable. The addition amount of the dispersion solvent is preferably 60 to 98% by weight based on the weight of the coating liquid.

The coating method of the present invention includes a blade coater, an air knife coater, a roll coater, a brush coater, a curtain coater, a chamber coats coater, which are generally used in the production of pigment-coated paper.
Both a bar coater and a gravure coater can be applied.

Drying after coating is carried out by an ordinary drying method such as a gas heater, an electric heater, a steam heating heater, or hot air heating to obtain a coated paper. The drying temperature is preferably 70 ° C to 220 ° C and 1 second to 30 minutes.

After coating and drying as described above, surface smoothness and coating layer strength can be imparted by, for example, calendering, passing between roll nips under heat and pressure.

The coating amount of the coating liquid described above is the dry weight.
20g / m in quantity^Two Or less, more preferably 0.3 to 10 g
/ M^Two It may be applied so that 0.3g coating amount
/ M ^Two When it is less than the above, the effect aimed at by the present invention is sufficiently
Could not be obtained, 20g / m^Two When it exceeds,
It is preferable because powder drops and jams will occur during paper feeding
Absent.

The above coating amount may be completed by one coating, but the total dry coating amount is 20 g / m even if the same surface is coated two or more times. ^It does not matter if it is ² or less. Further, the coating liquids used for coating two or more times may be the same, or two or more different coating liquids may be coated on the same surface.

The coating liquid may be applied to only one side of the base paper or both sides. If curling occurs when only one side is coated, a backing layer may be provided if necessary.

[0050]

EXAMPLES Next, the present invention will be described in more detail with reference to examples, but these examples do not limit the present invention in any way. Further, "parts" and "%" shown in the examples represent parts by weight and% by weight of the active ingredient, unless otherwise specified.

Example 1 Pigment: Alumina hydrate (Alumina hydrate A described in JP-A No. 7-89221, 18 parts, pseudo-bead (6%)-mite) Water resistant agent: imidazolium compound 9 parts (Shikoku Kasei Co., Ltd., trade name Curezol SFZ) (3%) Chelating agent: sodium ethylenediaminetetraacetate (EDTA 6 parts.4Na.4H ₂ O) pH 11.0 (2%) (Crest Co., Ltd. trade name CREST -400) Binder: polyacrylic amide 17.6 parts (manufactured by Hoshiko Kagaku Co., trade name X coat P-170, (1%) active ingredient concentration 17%) Solvent: water (ion exchanged water) 249.4 parts The above formulation 300 g of the water dispersion of above was stirred with a stirrer for 30 minutes, and then with a TK homomixer at 8000 rpm, 30
It was dispersed for a minute to obtain a coating liquid. This coating liquid is removed with a dropper while stirring, weighed 80 g / m ² , Steckigt size 56 seconds, thickness 100 μm, Hunter whiteness 81.2
% Base paper was evenly coated with a bar coater (No. 5) and dried in an oven at 90 ° C. for 15 minutes to obtain a recording paper.

Example 2 Of the coating liquid formulations used in Example 1, the chelating agent of the second liquid was hydroxyethyliminodiacetic acid pH 11.7 (HI).
DA ・ 2Na) (Product made by Kirest, brand name Kirest E-2
Substituting 5), a coating liquid was prepared by the same method, coated on the same base paper and dried to obtain a recording paper.

Example 3 Among the coating solution formulations used in Example 1, the chelating agent was ethylenediaminetetraacetic acid trisodium (EDTA.H.3N).
a) A coating liquid was prepared in the same manner by substituting pH 7.0 (Chillest C, trade name, CREST C.), coated on the same base paper and dried to obtain a recording paper.

Example 4 Of the coating liquid formulations used in Example 1, the chelating agent was ethylenediaminetetraacetic acid disodium salt (EDTA.2H.2N).
a) pH 4.4 (manufactured by Kirest, trade name Kirest 20)
0) to prepare a coating solution by the same method, and the same base paper was coated and dried to obtain a recording paper.

Example 5 Among the coating liquid formulations used in Example 1, the pigment was alumina hydrate (aluminum hydroxide: manufactured by Sumitomo Chemical Co., Ltd., trade name C-3).
Substituting 1), a coating solution was prepared by the same method, coated on the same base paper and dried to obtain a recording paper.

Example 6 In the coating liquid formulation used in Example 1, the waterproofing agent was replaced with polyamine sulfone (quaternary ammonium: manufactured by Nitto Boseki Co., Ltd., trade name PAS-A-1) and coated in the same manner. A working solution was prepared, coated on the same base paper and dried to obtain a recording paper.

Example 7 A similar method was carried out by substituting the water resistant agent in the coating liquid formulation used in Example 1 with polyallylamine hydrochloride (quaternary ammonium: Nitto Boseki Co., trade name PAA-HCl-3L). To prepare a coating solution, which was coated on the same base paper and dried to obtain a recording paper.

Example 8 A coating solution was prepared in the same manner as in Example 1 except that the water resistant agent was replaced with polyaluminum chloride (cationic substance: manufactured by Asada Chemical Co., Ltd., trade name PAC). It was prepared, coated on the same base paper and dried to obtain a recording paper.

The substances replaced in Examples 4 to 8 were adjusted to the same active ingredient concentration (% by weight) as in Example 1.

Example 9 A coating solution was prepared in the same manner by substituting benzalkonium (manufactured by Lion Corporation, trade name Cation O8B) for the waterproofing agent in the coating solution formulation used in Example 1 and using the same method. A recording paper was obtained by coating on a base paper and drying.

Reference Example 1 A coating liquid was prepared by adjusting the following formulation except the chelating agent (tetrasodium ethylenediaminetetraacetate) in the coating liquid formulation used in Example 1 by the same method.

Pigment: Alumina hydrate used in Example 1 18 parts (6%) Water resistance agent (quaternary ammonium): Imidazolium compound 9 parts (Shikoku Kasei, trade name Curezol SFZ) (3%) Binder: polyacrylic amide 17.6 parts (manufactured by Hoshiko Kagaku Co., trade name X coat P-170, active ingredient concentration 17%) (1%) Solvent: water (ion exchanged water) 255.4 parts The above coating liquid A base paper was coated and dried in the same manner as in Example 1 to obtain a recording paper.

Reference Example 2 Pigment (alumina hydrate) of the coating solutions used in Example 1
The following formulation except for was prepared in the same manner to obtain a coating liquid.

Water-proofing agent (quaternary ammonium): imidazolium compound 9 parts (trade name: CUREZOL SFZ, manufactured by Shikoku Kasei Co., Ltd.) (3%) Chelating agent: tetrasodium ethylenediaminetetraacetate (EDTA 6 parts / 4Na / 4H ₂ O) ) PH 11.0 (2%) (CHIRESTO, trade name CHIREST 400) Binder: polyacrylic amide 17.6 parts (Hoshiko Kagaku Co., trade name X coat P-170, active ingredient concentration 17%) (1 %) Solvent: Water (ion-exchanged water) 267.4 parts The above coating liquid was applied onto a base paper in the same manner as in Example 1 and dried to obtain a recording paper.

Reference Example 3 A coating solution was prepared by the same method except that the water resistant agent (imidazolium) was removed from the coating solution used in Example 1.

Pigment: Alumina hydrate used in Example 1 18 parts (6%) Chelating agent: Tetrasodium ethylenediaminetetraacetate 6 parts (EDTA.4Na.4H ₂ O) (2%) Binder: Polyacrylic amide 17 0.6 parts (trade name: X-Coat P-170, manufactured by Seikou Kagaku Co., active ingredient concentration: 17%) (1%) Solvent: Water (ion-exchanged water) 258.4 parts The same coating solution as in Example 1 was used. A base paper was coated by the method and dried to obtain a recording paper.

Reference Example 4 A coating solution was prepared in the same manner as in Example 1 except that calcium carbonate (trade name CS, manufactured by Calceed Co.) was used as the pigment in the coating solution formulation used in Example 1 and the same. A base paper was coated and dried to obtain a recording paper.

Each of the recording sheets of Examples 1 to 9 and Reference Examples 1 to 3 was recorded with an ink jet printer (Macintosh, color style writer pro) for yellow, magenta, cyan and black. The printed matter thus obtained was evaluated for color developability, image density, and water resistance. As an evaluation method, the color developability was visually inspected, and the evaluation was performed in three stages of A, B, and C in order from the one having a good cyan tint.

The image density is OD (Optical Den) by a reflection densitometer DM-800 manufactured by Dainippon Screen Co., Ltd.
The site) was measured. (Hereafter, the image density is OD
The water resistance is evaluated by leaving the obtained printed matter at room temperature for 5 hours, then immersing it in tap water for 3 seconds, leaving it at room temperature for drying, and visually observing the degree of image flow. I observed. The results were evaluated in 3 grades (○ -good, Δ-slightly bad, × -bad).

Table 1 shows the evaluation results of the recording sheets prepared in Examples and Reference Examples based on the above evaluation criteria.

[0071]

[Table 1] From the above results, only the inkjet recording paper coated with the coating solution of alumina hydrate in combination with the chelating agent and the water-proofing agent (quaternary ammonium) on the base paper is related to the color developability, image density and water resistance. It is obvious that all the characteristics are satisfied.

It can be seen that the chelating agent described in the present invention having a pH of 7 or more is more preferable.

It is understood that pseudo-boehmite is more preferable as the alumina hydrate, and quaternary ammonium, further benzalkonium and imidazolium are more preferable as the cationic substance.

[0074]

INDUSTRIAL APPLICABILITY As described above, the ink jet recording paper of the present invention has a texture similar to that of conventional plain paper, but is suitable not only for ink jets but also for electrophotographic copying machines, and is generally used for pencils, ballpoint pens and the like. The writing with a writing instrument can be done smoothly. The effects of the inkjet recording paper of the present invention are as follows. (1) Since the water-based ink has high absorptivity, it immediately becomes a dry state after the ink is attached, good color development is achieved, and a clear image having a sufficiently high image density can be formed. (2) It has excellent water resistance even after forming an image with a water-based ink, and does not cause image bleeding or flow due to water wetting. (3) Since the coating amount of the coating liquid is 20 g / m ² or less, which is significantly smaller than that of general coated paper, the material cost is low,
Suitable for mass production, inexpensive recording paper can be obtained.

Claims (7)

[Claims] 1. A support surface is coated with a coating liquid containing an alumina hydrate, a chelating agent and a cationic substance as active ingredients so that the dry weight is 20 g / m ² or less. An ink jet recording paper, characterized in that the active ingredient of the coating liquid is present inside. 2. The ink jet recording paper according to claim 1, wherein the chelating agent has a pH of 7 or more. 3. The chelating agent is ethylenediaminetetraacetic acid (EDTA), hydroxyethylethylenediaminetriacetic acid (HEDTA), hydroxyethylethylenediaminediacetic acid (DHEDDA), 1,3propanediaminetetraacetic acid (1,3PDTA), diethylenetriaminepentaacetic acid. Acetic acid (DTPA), triethylenetetramine hexaacetic acid (TT
HA), nitrilotriacetic acid (NTA), gluconic acid, dihydroxyethylglycine (DHEG), hydroxyethyliminodiacetic acid (HIMDA, HIDA), uramildiacetic acid (VDA), dimethylglyoxime, phytic acid,
The inkjet recording paper according to claim 1, comprising at least one selected from the above-mentioned water-soluble salts of acids and potassium sodium tartrate. 4. The ink jet recording paper according to claim 1, wherein the alumina hydrate is pseudo-boehmite. 5. The ink jet recording paper according to claim 1, wherein the cationic substance is quaternary ammonium. 6. The ink jet recording paper according to claim 1, wherein the cationic substance is a benzalkonium compound. 7. The ink jet recording paper according to claim 1, wherein the cationic substance is an imidazolium compound.