JP2002144705A - Ink jet recording medium and coating liquid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet recording medium excellent in ink absorbency, film forming properties and transparency and a coating liquid therefor. SOLUTION: In the ink jet recording medium, an ink absorbing layer includes an inorganic porous substance having fine pores with pore diameters of 1 to 200 nm in the pore diameter distribution obtained by a nitrogen adsorption method and a latex polymer, which is produced by copolymerizing a hydroxyl group-containing monomer and another polymerizable monomer. In addition, the coating liquid for the ink jet recording medium is disclosed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording paper used for ink jet printing and recording.
The present invention relates to an ink jet recording medium such as a sheet, a film, and a cloth, and a coating liquid for an ink jet recording medium used for manufacturing the same.

[0002]

2. Description of the Related Art The ink jet recording system has been used in a wide range of fields because of low noise at the time of recording, easy coloration, and high speed recording. However, high-quality paper and the like used for general printing have poor ink absorbency and drying properties, and have poor image quality such as resolution.Therefore, special papers that have improved these properties have been proposed. Recording paper coated with various inorganic pigments such as amorphous silica in order to increase the printing quality is disclosed. (JP-A-55-51583, JP-A-56-1485)
85, etc.) However, with the recent progress in the performance of ink jet printers, further improvement in the performance of the recording medium has been required, and satisfactory performance has not always been obtained with the above technology alone. In particular, insufficient ink absorptivity and bleeding due to an increase in the amount of ink ejected per unit area of the recording medium in order to obtain high image quality comparable to that of silver halide photographs are raised. Further, if the amount of the binder is reduced in order to increase the ink absorbency, the film-forming properties tend to be deteriorated, and there has not been obtained a film which sufficiently satisfies both. Further, the transparency of the ink absorbing layer is also required for high image quality and color density development comparable to silver halide photography.

[0003]

SUMMARY OF THE INVENTION The present invention relates to an ink jet recording medium having excellent ink absorbency, film formability and transparency.
Further, an object of the present invention is to provide an inkjet recording medium coating liquid.

[0004]

Means for Solving the Problems The present inventors have conducted various studies to solve the above problems, and as a result, have found the following ink jet recording medium containing a specific inorganic porous substance and a specific latex polymer. The present invention has been accomplished. That is, the present invention is as follows. (1) In an ink jet recording medium provided with one or more ink absorbing layers on a support, at least one of the ink absorbing layers has a pore diameter of 1 to 200 nm in a pore diameter distribution determined by a nitrogen adsorption method. An ink jet recording medium comprising: an inorganic porous material having pores; and a latex polymer obtained by copolymerizing a hydroxyl group-containing monomer and another polymerizable monomer. (2) The ink jet recording medium according to (1), wherein the inorganic porous substance is substantially silicon oxide.

(3) The volume average particle diameter DL of the inorganic porous substance measured by the dynamic light scattering method is 10 to 200 nm.
And the difference SB-SL between the converted specific surface area SL of the inorganic porous substance obtained from the DL and the nitrogen adsorption specific surface area SB by the BET method is 100 m ² / g or more (1) to (2).
3. The ink jet recording medium according to claim 1. (4) The ink jet recording medium according to any one of (1) to (3), wherein the ink absorbing layer contains a water-soluble resin. (5) Ingredients of the ink absorbing layer according to (1) to (4),
And an ink jet recording medium coating solution containing a solvent.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be specifically described below. In the invention, at least one ink absorbing layer is provided on the support. If necessary, two or more ink absorbing layers can be provided. As described above, by forming the ink absorbing layer into multiple layers, it is possible to share functions such as imparting gloss to the surface to each layer. The inorganic porous material of the present invention and the latex polymer need to be contained in at least one layer.

The inorganic porous material used in the present invention has a pore diameter of 1 to 200 nm in a pore diameter distribution determined by a nitrogen adsorption method.
More preferably, it is a crystalline or amorphous porous substance made of an inorganic substance having pores at 2 to 100 nm. That the inorganic porous material has pores with a predetermined pore size distribution,
It can be confirmed that the pore diameter giving the maximum value observed in the pore diameter distribution diagram of the inorganic porous substance is within a predetermined range. If the pores are less than this range, the ink absorbency decreases, and if the pores are larger than this range, the transparency of the ink absorbing layer decreases, which is not preferable. The inorganic substance is not particularly limited, but for example, silicon, aluminum, zirconium, titanium, tantalum, niobium, tin, metal oxides such as tungsten,
Examples include metal phosphates such as aluminum, vanadium, zirconium, and tungsten, and silicon oxide is particularly preferably used. A substance whose surface has been modified by substituting a part of the inorganic substance with another element or modifying it with an organic substance can also be used. 1 to 200 by nitrogen adsorption method
It is not particularly limited as long as it is a porous substance in which pores are detected in nm, but mesoporous silica synthesized using a surfactant or the like as a template (US Pat. No. 3,556,725, JP-A-5-503499, JP-A-5-503499, And other mesoporous materials. Mesoporous silica is a porous silica material having an average pore size in a mesopore region of 2 to 50 nm, which has a regular structure in powder X-ray diffraction and has a substantially uniform pore size. In the present invention, not only a substance whose X-ray diffraction regularity is recognized in the arrangement of the pores of the porous substance, but also a substance whose X-ray diffraction regularity is not recognized can be used.

In the present invention, the inorganic porous material has a volume average particle diameter DL of 10 to 10 as measured by a dynamic light scattering method.
Converted specific surface area SL and BE obtained from DL at 200 nm
The difference SB-SL from the nitrogen adsorption specific surface area SB by the T method is 1
A substance having a content of at least 00 m ² / g is preferably used from the viewpoint of the transparency of the ink absorbing layer. The converted specific surface area SL (m ² / g) calculated from the volume average particle diameter DL (nm) measured by the dynamic light scattering method assumes that the particles are spherical, and SL = 6 × 10 ³ / ( Density (g / cm ³ ) × DL). The substance has a small particle size and thus has excellent transparency of the ink absorbing layer, and has pores not only between particles but also inside the particles, which is preferable in terms of ink absorbability.
When the DL is less than 10 nm, the ink absorbency decreases, and
If it is larger than nm, the transparency of the ink absorbing layer is undesirably reduced. SB-SL is 10 in terms of ink absorbency.
It is preferably 0 m ² / g or more, more preferably 250 m ² / g or more, and if it is less than 100 m ² / g, the ink absorbency decreases, which is not preferable. The BET specific surface area (nitrogen adsorption specific surface area SB) of the substance is preferably from 200 to 1500 m ² / g, and the pore volume is preferably from 0.5 to 4 ml / g.

As a method for synthesizing the inorganic porous material, for example,
(A) SiO of silicon source_TwoBalance to reduced mass
Weight ratio of rate in the range of 0.01 to 30, template
The weight ratio of water to the weight of
Mixing silicon source and template to produce composite
And (b) removing a template from the complex.
It can be synthesized from the process. Template used here
Nonionic surfactants are preferably used as
Structural formula HO (C_TwoH_FourO)_a− (C_ThreeH₆O)_b− (C _TwoH
_FourO)_cH (however, a and c are 10 to 110, b is 30 to 7
Non-ionic surfactants represented by 0) are particularly preferred.
It is used well. Specifically, Pluronic P103,
P123 and P85 (manufactured by Asahi Denka). pore
To change the diameter, as an organic auxiliary, e.g. carbon number
6-20 aromatic hydrocarbons, alicyclic carbons having 5-20 carbon atoms
Hydrogen, aliphatic hydrocarbons having 3 to 16 carbon atoms,
Min and halogen substitutions should be used with the template.
Can be. Increase the pore size by using the organic auxiliary in combination
It is possible to The reaction between the silicon source and the template is
Dissolve and disperse silicon source in solvent and template
The mixture is dissolved and dispersed in a solvent and mixed and stirred.
Water or organic solvent
The reaction temperature is not particularly limited, but 5 to 150 ° C.
The reaction time is preferably 0.5 to 100 hours.
Can be.

In general, as a method for removing the template from the inorganic porous material-template complex, there are a method of firing the complex at a high temperature and a method of extracting it with a solvent. The method of extracting with a solvent is preferable in that the aggregation of particles can be suppressed and the template can be reused. For example, a method of extracting and removing a template with a solvent such as water or alcohol using an ultrafiltration device is suitably used. The content of the inorganic porous material in the ink absorbing layer is not particularly limited, but is preferably 10 to 99% by weight based on each ink absorbing layer containing the inorganic porous material. Also, 1 to 99% by weight based on the whole ink absorbing layer
It is preferred to contain. If the content is low, the ink absorbency decreases, which is not preferable.

It is necessary that the ink absorbing layer of the present invention contains a latex polymer obtained by copolymerizing a hydroxyl group-containing monomer and another polymerizable monomer as a binder. Such a copolymer latex polymer is, for example, a resin particle component in a resin dispersion obtained by a usual emulsion polymerization method from a predetermined polymerizable monomer. By using the copolymer latex polymer, the film formability of the recording medium can be improved without impairing the ink absorbency of the inorganic porous material.

The hydroxyl group-containing monomer is not particularly limited as long as it has a structure containing a hydroxyl group in the monomer, but 4-hydroxybutyl acrylate and acrylic acid 2
-Hydroxyethyl, 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, allyl alcohol, hydroxystyrene and the like. One or more of these hydroxyl group-containing monomers can be used. The content of the hydroxyl group-containing monomer unit in the latex polymer is not particularly limited, but is preferably 0.1 to 90% by weight. If the content is low, the film-forming properties are undesirably reduced.

The other polymerizable monomer is not particularly limited as long as it can be copolymerized with the hydroxyl group-containing monomer.
For example, vinyl acetate, styrene, α-methylstyrene, ethylene, isoprene, butadiene, vinyl chloride,
Methacrylic acid, methacrylic acid ester such as methyl methacrylate, butyl methacrylate, cyclohexyl methacrylate, acrylic acid, ethyl acrylate, butyl acrylate, acrylic acid ester such as acrylic acid (2-ethylhexyl), amide derivative such as acrylamide, Acrylonitrile, methacrylonitrile and the like can be mentioned. One or more of these polymerizable monomers can be used.

When only a water-soluble binder such as a conventional polyvinyl alcohol is used as the binder for the inorganic porous material of the present invention, the ink absorption is reduced at a level where the film formability is good, and the amount of the ink is reduced. When the amount is reduced, the ink absorbency is improved, but the film formability is reduced. On the other hand, when the inorganic porous material of the present invention and a latex polymer are used in combination, it is possible to achieve both ink absorption and film formation. Although the reason for this is not clear, it is speculated that in the ink absorption layer, the particle diameter of the latex polymer is larger than the pores of the porous substance, so that the pores are not closed, and good ink absorbency is exhibited. I have.

The glass transition point and the average particle diameter of the latex polymer used in the present invention are not particularly limited, but those having a glass transition point of -30 to 100 ° C. and an average particle diameter of 5 to 200 nm are preferably used. The content of the latex polymer used in the present invention is not particularly limited, but is preferably 5 to 400 parts by weight, particularly preferably 5 to 100 parts by weight, based on 100 parts by weight of the inorganic porous material. If the content is small, the film-forming property is reduced, and if the content is large, the ink absorbency is reduced, which is not preferable.

In the present invention, it is preferable to use a water-soluble resin in combination with a latex polymer in the ink-absorbing layer in order to impart better film-forming properties. Examples of the water-soluble resin include, but are not particularly limited to, polyvinyl alcohol, cationically modified polyvinyl alcohol, polyvinyl alcohol derivatives such as silanol-modified polyvinyl alcohol, polyvinyl pyrrolidone, polyacrylamides, starch and starch derivatives, carboxymethyl cellulose, cellulose derivatives such as hydroxyethyl cellulose, casein. , Gelatin and the like, and polyvinyl alcohol derivatives such as polyvinyl alcohol, cationically modified polyvinyl alcohol, and silanol-modified polyvinyl alcohol are more preferably used. The content of the water-soluble resin used in the present invention is 1 to 100 parts by weight of the latex polymer.
The content is preferably 400 parts by weight, particularly preferably 5 to 100 parts by weight. If the content is small, the effect is not sufficient, and if the content is large, the ink absorbency decreases, which is not preferable.

In the present invention, there is also provided an ink jet recording medium coating liquid comprising the components of the ink absorbing layer described in (1) to (4) and a solvent. The solvent used is not particularly limited, but water-soluble solvents such as alcohols, ketones and esters, and / or water are preferably used. Further, a pigment dispersant, a thickener, a flow regulator, an antifoaming agent, a foam inhibitor, a release agent, a foaming agent, a colorant, and the like can be added to the coating liquid as needed. In the present invention, other organic binders can be used in combination. For example, polyvinyl acetates, polyacetals, polyurethanes, polyvinyl butyrals, poly (meth) acrylic acids (esters),
Examples include polyamides, polyester resins, urea resins, and melamine resins.

In the present invention, at least one of the ink absorbing layers preferably contains a cationic polymer. By containing the cationic polymer, the water resistance of the printed portion is improved. The cationic polymer is not particularly limited as long as it shows cationicity, and primary amine, secondary amine, tertiary amine substituent and salts thereof,
Those containing at least one quaternary ammonium salt substituent are preferably used. For example, dimethyldiallylammonium chloride polymer, dimethyldiallylammonium chloride-acrylamide copolymer, alkylamine polymer, polyaminedicyanic polymer, polyallylamine hydrochloride and the like can be mentioned. The molecular weight of the cationic polymer is not particularly limited, but the weight average molecular weight is 1,000.
~ 200,000 are preferably used.

In the present invention, at least one of the ink absorbing layers preferably contains an ultraviolet absorber, a hindered amine light stabilizer, a singlet oxygen quencher, and an antioxidant. The light resistance of the printed portion is improved by containing the substance. The UV absorber is not particularly limited, but may be a benzotriazole-based, benzophenone-based, titanium oxide,
Cerium oxide, zinc oxide and the like are preferably used. The hindered amine light stabilizer is not particularly limited, but the N atom of the piperidine ring is NR (R is a hydrogen atom, an alkyl group, a benzyl group, an allyl group, an acetyl group, an alkoxyl group, a cyclohexyl group, a benzyloxy group). Are preferably used. The singlet oxygen quencher is not particularly limited, but aniline derivatives, organic nickel compounds, spirochromane compounds, and spiroindane compounds are preferably used. The antioxidant is not particularly limited, but includes phenol-based, hydroquinone-based, organic sulfur-based, phosphorus-based,
An amine type is preferably used.

In the present invention, at least one of the ink absorbing layers preferably contains an alkaline earth metal compound. By containing an alkaline earth metal compound, light resistance is improved. As the alkaline earth metal compound, magnesium, calcium and barium oxides, halides and hydroxides are preferably used. The method for incorporating the alkaline earth metal compound into the ink absorbing layer is not particularly limited. It may be added to the coating liquid slurry, or may be added at the time of synthesizing the inorganic porous substance or after the synthesis, and may be used by adhering and containing. The amount of the alkaline earth metal compound to be used is from 0.5 to 0.5 in terms of oxide based on 100 parts by weight of the inorganic porous material.
20 parts by weight are preferred.

In the present invention, at least one of the ink absorbing layers preferably contains a nonionic surfactant. Image quality by containing nonionic surfactant,
Light resistance is improved. The nonionic surfactant is not particularly limited, but a higher alcohol, an ethylene oxide adduct of a carboxylic acid, an ethylene oxide-propylene oxide copolymer is preferably used, and an ethylene oxide-propylene oxide copolymer is more preferably used. . The method for incorporating the nonionic surfactant into the ink absorbing layer is not particularly limited. It may be added to the coating liquid slurry, or may be added at the time of synthesizing the inorganic porous substance or after the synthesis, and may be used by adhering and containing.

In the present invention, at least one of the ink absorbing layers preferably contains an alcohol compound. By containing an alcohol compound, image quality and light resistance are improved. The alcohol compound is not particularly limited, but an aliphatic alcohol, an aromatic alcohol, a polyhydric alcohol, and a hydroxyl group-containing oligomer are preferably used, and a polyhydric alcohol is more preferably used. The method for including the alcohol compound in the ink absorbing layer is not particularly limited.
It may be added to the coating liquid slurry, or may be added at the time of synthesizing the inorganic porous substance or after the synthesis, and may be used by adhering and containing.

In the present invention, at least one of the ink absorbing layers preferably contains alumina hydrate. The image quality and water resistance are improved by containing alumina hydrate. The alumina hydrate is not particularly limited, and a boehmite-structure, a pseudo-boehmite-structure, or an amorphous-structure alumina hydrate is used, and a pseudo-boehmite-structured alumina hydrate is preferably used. In the present invention, when at least one of the ink absorbing layers contains colloidal silica and / or dry silica, which preferably contains colloidal silica and / or dry silica, the image quality is improved and gloss can be imparted. No particular limitation is imposed on the colloidal silica, and ordinary anionic colloidal silica,
Cationic colloidal silica obtained by a method such as reacting a polyvalent metal compound such as aluminum ion is used. The fumed silica is not particularly limited, but fumed silica synthesized by burning silicon tetrachloride with hydrogen and oxygen is preferably used. The dry-process silica may be used as it is, or may be one whose surface is modified with a silane coupling agent or the like.

In the present invention, a gloss layer can be provided as the outermost layer. The means for providing the glossy layer is not particularly limited, but a method of containing an ultrafine particle pigment such as colloidal silica and / or dry silica, a super calender method, a gloss calender method, a casting method, and the like are used. The support used in the present invention is not particularly limited, but paper,
Polymer sheets, polymer films, and cloths are preferably used. These supports may be subjected to a surface treatment such as corona discharge, if necessary. The thickness of the ink absorbing layer is not particularly limited, but is 1 to 100 μm, and the coating amount is 1 to 100.
g / m ² is preferred. The coating method of the coating liquid is not particularly limited, but a blade coater, an air knife coater, a roll coater, a brush coater, a curtain coater, a bar coater, a gravure coater, a spray, or the like can be used.

Next, the present invention will be described based on embodiments.
The pore distribution, pore volume, and specific surface area were measured with Nitro using Autosorb-1 manufactured by Qantachrome. The pore size distribution was calculated by the BJH method. The specific surface area was determined by the BET method. The volume average particle diameter by the dynamic light scattering method is Lee
It was measured by a Microtrac UPA particle size distribution meter manufactured by ds & Northrup. X-ray powder analysis diagram is RIKEN RI
The measurement was performed using NT2500.

Evaluation of printing characteristics was performed using a commercially available inkjet printer (PM-800C manufactured by Seiko Epson) using yellow, magenta, cyan, black, green,
Red and blue solid prints were used. Evaluation items are shown below. (1) Ink absorbency: Judgment was made based on the degree of ink transfer after printing, and the degree of ink transfer, with the printed portion being pressed with white paper immediately after printing. ：: good, Δ: slightly good, ×: poor (2) Film-forming property: Cracking and adhesion of the coating film were visually judged. ○: good, Δ: slightly good, ×: poor

[0027]

Examples 1 to 3 A cation exchange resin (Amberlite, IR-120B) 100 previously converted to H @ + type
g water dispersed in 100 g of water, and water glass No. 3 (SiO
₂ = 29% by weight, Na ₂ O = 9.5% by weight) 33.3 g
Is diluted with 66.7 g of water. After sufficiently stirring this, the cation exchange resin was separated by filtration to obtain 200 g of an active silica aqueous solution. The aqueous SiO ₂ solution contained 5.0% by weight of SiO ₂ . 5 g of Pluronic P103 (ethylene oxide-propylene oxide copolymer) manufactured by Asahi Denka Co., Ltd. was dissolved in 1360 g of water, and 60 g of the above-mentioned active silica aqueous solution was added while stirring in a 35 ° C water bath. Further, 20 ml of a 0.015 mol / l NaOH aqueous solution was added. The pH of this mixture was 7.5.
The mixture was stirred at 35 ° C. for 15 minutes and then allowed to stand at 80 ° C. for 2 minutes.
The reaction was performed for 4 hours. Pluronic P103 was removed from this solution using an ultrafiltration apparatus, and the SiO ₂ concentration was 4% by weight.
Was obtained. The volume average particle diameter of the sample in this solution measured by the dynamic light scattering method is 6
At 0 nm, the converted specific surface area was 45 m ² / g. This solution was dried at 105 ° C. to obtain a porous substance. No peak was observed in the X-ray diffraction pattern of this sample. The maximum value in the pore diameter distribution diagram of this sample was observed at a pore diameter of 8 nm, and the pore volume was 1.21 ml / g. The nitrogen adsorption specific surface area by the BET method was 720 m ² / g, and the difference from the converted specific surface area was 675 m ² / g.

A coating liquid was prepared by mixing a hydroxyl group-containing monomer copolymer latex polymer with 100 parts by weight of SiO _{2 at} a ratio shown in Table 1 to this sol solution of the porous substance.
Polyethylene terephthalate sheet (thickness 100μ)
m) was coated with the coating liquid using a bar coater and dried to obtain a recording sheet provided with an ink absorbing layer having a thickness of about 25 μm.
All of the obtained recording sheets were transparent. Table 1 shows the evaluation results of these sheets.

[0029]

Example 4 A recording sheet was obtained in the same manner as in Example 1 except that the silanol-modified polyvinyl alcohol was mixed in the sol solution of the porous substance at the ratio shown in Table 1. The obtained recording sheet was transparent. Table 1 shows the evaluation results of this sheet.

[0030]

Comparative Examples 1 and 2 A recording sheet was obtained in the same manner as in Example 1 except that only the polyvinyl alcohol and the silanol-modified polyvinyl alcohol were mixed in the sol solution of the porous material at the ratios shown in Table 1. . All of the obtained recording sheets were transparent. Table 1 shows the evaluation results of these sheets.

[0031]

[Table 1]

[0032]

The ink jet recording medium of the present invention has excellent effects on ink absorption, film formation and transparency.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2C056 EA05 FC06 2H086 BA15 BA33 BA34 BA35 BA41 BA48 4J002 BG071 DE096 DE136 DE146 DH046 DJ016 FA096 FD206 GS00 HA06

Claims (5)

[Claims] 1. In an ink jet recording medium having one or more ink absorbing layers provided on a support, at least one of the ink absorbing layers has a pore diameter of 1 to 3 in a pore diameter distribution determined by a nitrogen adsorption method. An ink jet recording medium comprising: an inorganic porous substance having pores of 200 nm; and a latex polymer obtained by copolymerizing a hydroxyl group-containing monomer and another polymerizable monomer. 2. The ink jet recording medium according to claim 1, wherein the inorganic porous substance is substantially silicon oxide. 3. The inorganic porous material has a volume average particle diameter DL of 10 to 200 nm measured by a dynamic light scattering method, and the reduced specific surface area S of the inorganic porous material determined from the DL.
Difference between L and the specific surface area SB of nitrogen by the BET method SB−
The inkjet recording medium according to claim 1, wherein SL is 100 m ² / g or more. 4. The ink jet recording medium according to claim 1, wherein the ink absorbing layer contains a water-soluble resin. 5. An ink jet recording medium coating liquid comprising the ink absorbing layer constituent components according to claim 1 and a solvent.