JP2009249430A - Modified inorganic pigment, method for producing modified inorganic pigment sol, inkjet recording unit and method for producing inkjet recording unit - Google Patents

Abstract

The present invention provides a modified inorganic pigment useful for a silver salt photographic glossy inkjet recording material, which is particularly difficult to blur images and has excellent light resistance.
The surface of an inorganic pigment is modified with a treatment liquid containing a hydrophilic resin having a cation equivalent of 4.0 meq / g or more, an amino group-containing silane coupling agent, an organic acid and an inorganic acid. It is a modified inorganic pigment. Moreover, after dissolving an amino group-containing silane coupling agent in a polar solvent, an organic acid and an inorganic acid are added, and selected from polymers containing polyvinylamine, polyallylamine, polydiallyldimethylammonium chloride, and 5-membered ring amidine structure. A method for producing a modified inorganic pigment sol, comprising dispersing an inorganic pigment in a treatment liquid to which at least one hydrophilic resin is added.
[Selection figure] None

Description

  The present invention relates to a modified inorganic pigment particularly useful for a silver salt photographic glossy ink jet recording material that is difficult to bleed and has excellent light resistance, a method for producing the same, and an ink jet recording material using the same.

  Various output systems such as a wire dot recording system, a thermal coloring recording system, a melt thermal transfer recording system, a sublimation recording system, an electrophotographic system, and an ink jet recording system have been developed so far. Above all, the inkjet recording method is recognized as a recording method suitable for personal use because of the fact that plain paper can be used as a recording sheet, the running cost is low, and the hardware is compact and inexpensive. Has stretched to. With the widespread use of hardware, full-color, high-speed, and high-quality images have rapidly advanced, so output applications can be expanded from simple monochrome text output to digital image output that can replace silver halide photography. However, the quality required for the recording sheet side is stricter.

  Among commercially available ink jet recording media, the sales volume of glossy paper is rapidly increasing as a medium capable of outputting a silver salt photographic full color image in recent years. In the production of glossy paper, how to “get close to a silver salt photograph” is an important key, and not only “print image quality” but also “can maintain the obtained image quality for a long time” is required. With regard to “print image quality”, recording that enables further improvement within the scope of demands for improvement in ink absorption speed, which became more severe as the printing speed of printers increased, and restrictions on raw material costs due to lower prices for glossy paper Body material development is needed. Among them, “image light resistance and ozone resistance”, which was greatly inferior to silver salt photography, has been improved to some extent by recent improvements in ink, but there is still an aspect that still needs improvement regarding image fixability. is there. Ink for ink jet printers has a dye or pigment dye dissolved or dispersed in a solvent. In order to sufficiently fix the dye after printing on the recording medium, it is necessary to remove the ink solvent by means such as vaporization. However, when trying to output a plurality of photographic images easily, glossy paper after printing will be in a state of being sequentially stacked (soon after the ink solvent is dried) on the printer's discharge tray. It is difficult to evaporate the solvent. If the ink solvent is confined in the recording paper, the dye that is not sufficiently fixed diffuses in the receiving layer as the ink solvent diffuses.Therefore, the sharpness of the printed image and blurring tend to occur. It is. In particular, a stronger ink fixing property is required in order to keep the skin color that is visually sensitive and the uniformity of the dark solid portion well even under severe output conditions.

  In order to obtain a vivid output image and retain it, a stable combination is required even when the ink solvent remains in a state that is highly reactive with the dye that is a dye or pigment contained in the ink. It is necessary to include a “cationic fixing agent” that can be formed in the inkjet recording medium on the receiving side. It is important that such a fixing agent can be quickly bonded and insolubilized when ink is printed. Currently, in many commercially available ink jet recording materials, a water-soluble cationic resin is generally used as the fixing agent. For example, as disclosed in JP-A-60-61887 (see Patent Document 1), polyallylamines that have long been known to have excellent ink fixing ability, and JP-A-2004-122769. A “water-soluble cationic resin containing a primary amine structure” such as a cationic resin containing a 5-membered ring amidine structure, which is disclosed in (Patent Document 2) and has good image storage stability of a dye ink, is suitable. However, recent high-quality ink for inkjet printers is a mixture made by combining multiple color components composed of various dyes or pigments with various structures, so it can fix a full-color image with a single fixing agent. It is a very difficult situation. Even if the fixing ability is improved simply by increasing the amount of the cationic resin, the effect cannot be expected so much, and there is a high possibility that the ink absorption, which is a capillary phenomenon, will be inhibited. Furthermore, these cationic resins are easy to absorb moisture and may move relatively easily in the ink receiving layer, and may be relatively deteriorated by changes in external environment and stimuli such as high temperature and high humidity, light and ozone. This is easy and may cause deterioration of image storability and blank sheet storability, so care must be taken when setting the addition amount. In addition, depending on the amount added, the image light resistance may be significantly reduced. In view of the above background, it has been desired to develop a fixing agent having a higher quality than the use of a cationic resin alone.

  In order to ensure the fixing ability while reducing the amount of the cationic resin used, Japanese Patent Application Laid-Open No. 2001-10209 (see Patent Document 3) proposes to use a silane coupling agent in combination with a cationic resin as a fixing agent. In particular, it is clearly stated that it is preferable to use a silane coupling agent having a cationic quaternary ammonium structure. The silane coupling agent itself is a material that has been used for a long time as a surface treatment agent for pigments used in ink jet recording materials, as described in JP-A-62-178384 (see Patent Document 4). When a cationic silane coupling agent is used as a fixing agent for the ink receiving layer, the cationic group is more strongly bonded or adsorbed to the surface of the pigment, which is the main component of the ink receiving layer, than the cationic resin, and is therefore resistant to external stimuli. It is expected that the ink absorption and image storage stability will be improved. However, even if this cationic silane coupling agent was used alone as an ink fixing agent, sufficient ink fixing ability could not be obtained, so the quality of the image tends to be inferior particularly in a high temperature and high humidity environment. there were.

  In JP-A-2003-127532, JP-A-2003-305944, and JP-A-2003-326843 (see Patent Documents 5 to 7), ink jet recording using a silane coupling agent and an organic mordant in various configurations. Bodies have been proposed and polyallylamine is mentioned as a preferred organic mordant. However, although the ink jet recording medium having these configurations has good ink fixing ability, the image light resistance is inferior, so that the intended quality is not satisfied.

JP-A-60-61887 JP, 2004-122769, A Claim 1 JP, 2001-10209, A Claims 1 and 2 JP, 62-178384, A Claim 1 JP, 2003-127532, A JP, 2003-305944, A Claims 4 and 13 JP, 2003-326843, A Claims 2 and 3

  The inventors of the present invention have made improvements in order to obtain a high-quality ink jet recording material that overcomes these drawbacks. As a means for obtaining a high ink fixing ability, various studies have been made on modifying the inorganic pigment, which is the main component of the ink receiving layer of the ink jet recording material, to be cationic.

  The present invention further improves the conventional ink fixing technology, and has a high fixing power for many types of inks, and even when the ink jet recording body formed thereby is laminated immediately after printing by continuous printing. The present invention provides a modified inorganic pigment which can be used suitably for an ink receiving layer of a silver salt photographic tone ink jet recording material, capable of forming a clear image and having good image light resistance. The present invention also provides a preferred method for producing the modified inorganic pigment sol, an ink jet recording material using the modified inorganic pigment, and a method for producing the same.

  The inventors of the present invention have worked on "a combination use of an amino group-containing silane coupling agent and a cationic resin" as a modification material of an inorganic pigment that is a main component of an ink receiving layer of a glossy ink jet recording medium as an alternative to silver salt photography. . However, as in the conventional knowledge, when a cationic resin is used in order to obtain sufficient ink fixing ability, image light resistance deteriorates.

However, as a result of further investigations, a strong cationic hydrophilic resin having a cation equivalent of 4.0 meq / g or more was selected as a treatment solution and an amino group-containing silane coupling agent as a treatment solution, and an organic acid It was found that when an inorganic pigment and an inorganic acid are mixed as essential components and the inorganic pigment is modified with this treatment liquid, a decrease in image light fastness is suppressed and an ink jet recording ability is excellent. The cation equivalent is an equivalent (mmol) of a cationic group (total of amino group and ammonium group) contained per 1 g of the polymer, and is a value represented by meq / g.
A polymer containing polyvinylamine, polyallylamine, polydiallyldimethylammonium chloride and a 5-membered ring amidine structure, which is excellent in ink fixing ability as long as the essential conditions of the treatment liquid are satisfied, but is likely to cause a decrease in image light resistance. Even when a cationic resin such as the above was used, good image light resistance was obtained. The reason why the image light resistance can be maintained even when these cationic resins are used is considered to be the combined use of an organic acid and an inorganic acid, although the reason is not clear.

Accordingly, this application includes the following inventions:
(1) A modification characterized by modifying the surface of an inorganic pigment with a treatment liquid containing a hydrophilic resin having a cation equivalent of 4.0 meq / g or more, an amino group-containing silane coupling agent, an organic acid and an inorganic acid. Quality inorganic pigments.
(2) Contains at least one hydrophilic resin selected from polymers containing polyvinylamine, polyallylamine, polydiallyldimethylammonium chloride and a 5-membered ring amidine structure, an amino group-containing silane coupling agent, an organic acid and an inorganic acid A modified inorganic pigment, wherein the surface of the inorganic pigment is modified with a treatment liquid.
(3) The modified inorganic pigment according to either (1) or (2), wherein the hydrophilic resin has a weight average molecular weight of 5,000 to 100,000.
(4) When the amino group-containing silane coupling agent is 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, N-2- ( It is at least one selected from aminoethyl) -3-aminopropyltriethoxysilane and N-2- (n-butyl) -3-aminopropyltrimethoxysilane or a hydrolyzate and polymer thereof ( The modified inorganic pigment according to any one of 1) to (3).
(5) The modified inorganic pigment according to any one of (1) to (4), wherein the organic acid and the inorganic acid are monovalent acids.
(6) The modified inorganic pigment according to any one of (1) to (5), wherein the organic acid is a carboxylic acid or a hydroxycarboxylic acid.
(7) The modified inorganic pigment according to any one of (1) to (6), wherein the inorganic pigment is gas phase method silica having primary particles of 40 nm or less.
(8) An ink jet recording material comprising the modified inorganic pigment according to any one of (1) to (7).

(9) After dissolving an amino group-containing silane coupling agent in a polar solvent, an organic acid and an inorganic acid are added, and a polymer containing polyvinylamine, polyallylamine, polydiallyldimethylammonium chloride and a 5-membered ring amidine structure is added. A method for producing a modified inorganic pigment sol, comprising dispersing an inorganic pigment in a treatment liquid to which at least one hydrophilic resin selected is added.
(10) The method for producing a modified inorganic pigment sol according to (9), wherein a mechanical share is given after adding an inorganic pigment to the treatment liquid.
(11) The method according to (9) or (10), wherein the ink receiving layer coating liquid is applied to the support and dried to form an ink receiving layer. A method for producing an ink jet recording material, comprising the modified inorganic pigment sol obtained in (1).

  The modified inorganic pigment of the present invention has excellent fixing ability with respect to many types of inks and excellent image light resistance. Therefore, the modified inorganic pigment of the present invention can be preferably used for the production of an ink receiving layer of an ink jet recording material, and the ink jet recording material has a clear image even when it is laminated immediately after printing by continuous printing. Since it can be formed, it is useful as an alternative to silver salt photography by glossy finishing.

[Modified inorganic pigment]
The modified inorganic pigment of the present invention is a treatment liquid containing a hydrophilic resin having a cation equivalent of 4.0 meq / g or more, an amino group-containing silane coupling agent, an organic acid and an inorganic acid, and modifies the surface of the inorganic pigment. Obtained. The conditions and preparation methods for the hydrophilic resin, amino group-containing silane coupling agent, organic acid, inorganic acid and inorganic pigment, which are raw materials for the modified inorganic pigment, having a cation equivalent of 4.0 meq / g or more are shown below.

“Hydrophilic resin with a cation equivalent of 4.0 meq / g or more”
The hydrophilic resin having a cation equivalent of 4.0 meq / g or more is not particularly limited as long as the cation equivalent of 4.0 meq / g or more is satisfied. For example, the hydrophilic resin generally called a cation resin is used. Examples thereof include homopolymers, copolymers, derivatives and the like of the conductive resin. The cation equivalent shown here is an equivalent (mmol) of a cationic group (total of amino group and ammonium group) contained per gram of the polymer, and is a value represented by meq / g.
For example, polyalkylene polyamines such as polyethylene polyamine and polypropylene polyamine or derivatives thereof, polymers of (meth) acrylates having primary to tertiary amino groups and quaternary ammonium groups, primary to tertiary amino groups and fourth Polymer of (meth) acrylamide derivative having secondary ammonium group, vinylamine polymer or derivative thereof, allylamine polymer or derivative thereof, diallylamine polymer, diallylmethylamine polymer, diallyldimethylammonium chloride polymer, diallylamine-sulfur dioxide Polymerization, diallyldimethylammonium chloride-sulfur dioxide copolymer, acrylamide-diallylamine copolymer, acrylamide-diallyldimethylammonium chloride copolymer, dicyandiamide-formalin polycondensation Dicyan-based cationic resin, dicyandiamide-diethylenetriamine polycondensated polyamine-based cationic resin, epichlorohydrin-dimethylamine addition polymer, acrylonitrile-N-vinylformamide copolymer hydrolyzate, polyvinylamidine resin Among them, those having a cation equivalent of 4.0 meq / g or more are used singly or in combination.
From the viewpoint of the ink fixing ability, polyallylamine (PAA-15C manufactured by Nittobo Co., Ltd.), polydiallyldimethylammonium colloid (Unisense CP-102 manufactured by Senka Co., Ltd.), Himax SC-700M manufactured by Hymo Co., Ltd., etc. A polymer containing a 5-membered ring amidine structure or polyvinylamine is preferred.

  The preferred molecular weight of the hydrophilic resin varies depending on the type and amount of the hydrophilic polymer and the formulation of the treatment liquid, and is not particularly limited. However, if it is too low, the ink fixing ability is lowered. Increases the viscosity of the dispersion. Accordingly, although not particularly limited, the weight average molecular weight is 1,000 to 400,000, more preferably 3000 to 200,000, and most preferably 5000 to 100,000.

"Amino group-containing silane coupling agent"
When the amino group-containing silane coupling agent is dissolved in a solvent containing water, a silanol group is generated by hydrolysis, and some silanol groups are condensed with each other to form a Si—O—Si bond. Therefore, a silane coupling agent usually has 2 or 3 silanol-forming groups in water, and usually exists as a polymer as a result of the progress of formation of Si—O—Si bonds. Since the treatment liquid of the present invention contains an acid as an essential component and has an effect of promoting the hydrolysis reaction of the amino group-containing silane coupling agent, the amino group-containing silane coupling agent is quickly used in the treatment liquid. It is presumed that the inorganic pigment is modified together with the cationic hydrophilic resin used together with the formation of a polymer.

The specific structure of the amino group-containing silane coupling agent is not particularly limited, but 3-aminopropyltrimethoxysilane (CAS number 4369-14-6), 3-aminopropyltriethoxysilane (CAS number). 21142-29-0), N-2- (aminoethyl) 3-aminopropyltrimethoxysilane (CAS number 1760-24-3), N-2- (aminoethyl) -3-aminopropyltriethoxysilane (CAS) No. 5089-72-5), N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane (CAS No. 3069-29-2), N-phenyl-3-aminopropyltrimethoxysilane (CAS No. 3086) 76-6), 3-triethoxysilyl-N- (1,3-dimethyl-butylidene) propyl Pyramine, N-2- (n-butyl) -3-aminopropyltrimethoxysilane and the like can be exemplified, and silane coupling agents from various companies such as Shin-Etsu Chemical Co., Ltd., GE Toshiba Silicone Co., Ltd. and Toray Dow Corning Co., Ltd. It is marketed with the name. Among them, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropyltriethoxy Silane, N-2- (n-butyl) -3-aminopropyltrimethoxysilane, among amino group-containing silane coupling agents, has a high cationic property and a silanol group because of its low molecular weight per amino group. Since there are many alkoxyl groups, the polymerization reactivity is high, and it is used suitably.
Also, commercially available hydrolysis solutions of amino group-containing silane coupling agents (for example, trade name: KBP-90, manufactured by Shin-Etsu Chemical Co., Ltd .: 32% aqueous solution), and polymers of amino group-containing silane coupling agents. A solution (for example, Sila Ace S-330, Sila Ace S-320, manufactured by Chisso Corporation) or the like can be used or used together.

The amino group-containing silane coupling agent is preferably hydrolyzed in advance in order to convert the alkoxyl group into a silanol group. However, since the acid which is an essential component of the present invention serves as a catalyst for hydrolysis, it is considered that the hydrolysis proceeds relatively quickly in the present invention.
The solvent for the hydrolysis is not particularly limited as long as the silane coupling agent after hydrolysis can be uniformly dissolved, but water that is an essential component of the reaction is most preferable. The concentration of the amino group-containing silane coupling agent at the time of hydrolysis is not particularly limited, but if it is too low, the concentration of the aqueous dispersion of the modified inorganic pigment obtained will decrease, and if it is too high, the temperature will increase due to reaction heat. Since it becomes intense, Preferably it is 0.1-50 mass%, More preferably, it is 0.5-45 mass%, Most preferably, 1-40 mass% is suitable. Moreover, when diluting an amino group containing silane coupling agent in a solvent in order to suppress generation | occurrence | production of the gel-like substance which is an excessive polymer, it is good to add it gradually in the state which stirred the solvent.

"Organic and inorganic acids"
In the present invention, an organic acid and an inorganic acid are used in combination as essential components of the treatment liquid. Due to the combined effect of the organic acid and the inorganic acid, it is considered that the ink fixing ability and the image light resistance of the ink jet recording material are compatible even if a cationic resin that tends to decrease the image light resistance is used together.
The type of acid is not particularly limited, but representative examples include hydrofluoric acid, hydrochloric acid, hydrobromic acid, nitric acid, sulfuric acid, phosphoric acid, formic acid, acetic acid, propionic acid, glycolic acid, lactic acid, oxalic acid, Citric acid, malic acid, phthalic acid, etc. can be exemplified. In addition, various kinds of inorganic acids, organics described in “Chemical Handbook Basic Edition, Revised 5th Edition (Chemical Society of Japan, published by Maruzen Co., Ltd.) Chapter 11” Acid can be used.

Among various acids, monovalent acids are preferably used as these acids because of less viscosity increase when the modified inorganic pigment is applied to a coating solution. Specific examples of suitable inorganic acids include nitric acid and hydrochloric acid. As the organic acid, carboxylic acid is preferable because coarse particles are not generated when the inorganic pigment is modified, and particle size control is relatively easy. Examples thereof include formic acid and acetic acid. Among carboxylic acids, hydroxycarboxylic acid having a hydroxyl group can be most suitably used. Specifically, α-lactic acid and glycolic acid can be said to be the most suitable materials in terms of price and performance.
These acids can be expected to have effects such as promoting the hydrolysis of the amino group-containing silane coupling agent and enhancing the stability of the silanol groups to be generated to suppress excessive polymerization. Therefore, it is good to mix the amino group-containing silane coupling agent and the acid before mixing with the cationic resin, but the order of addition is not particularly limited, and it is previously mixed with the solvent before dropping the silane coupling agent. Alternatively, the solution after dropping may be mixed later. However, when a gel-like product that is an excessive polymerization product of an amino group-containing silane coupling agent is likely to be generated, an acid may be added after the amino group-containing silane coupling agent is dropped into the solvent. In addition, you may add in the state which mixed the inorganic acid and the organic acid, or may add separately.

"Processing liquid"
As described above, a hydrophilic resin having a cation equivalent of 4.0 meq / g or more, an amino group-containing silane coupling agent, an organic acid and an inorganic acid are prepared as a treatment liquid using a polar solvent (for example, water) as a solvent. The mixing order, pH, temperature and time, or stirring conditions may be appropriately adjusted and are not particularly limited.

The mixing ratio of the hydrophilic resin having a cation equivalent of 4.0 meq / g or more, which is a cation component contained in the treatment liquid, and the amino group-containing silane coupling agent is the type of both components, specifically the type of cation resin. And the cation equivalent, the number of amino groups and alkoxyl groups of the amino group-containing silane coupling agent, the type of metal compound, etc. However, generally, when the mixing ratio of the cationic resin is too large, the light resistance of the image becomes insufficient, or the dispersion of the modified inorganic pigment tends to have a high viscosity, and the mixing ratio of the amino group-containing silane coupling agent is If the amount is too large, there is a tendency that the ink fixing ability tends to be insufficient, and if either of them is too small, the effect of using the two in combination cannot be obtained.
As an example of a specific mixing weight ratio, “an amino group-containing silane coupling agent is 10 to 500 parts by weight, preferably 50 to 400 parts per 100 parts by weight of the hydrophilic resin having a cation equivalent of 4.0 meq / g or more. Parts by weight, more preferably 100 to 300 parts by weight ", but is not limited thereto.
In addition to the hydrophilic resin having an cation equivalent of 4.0 meq / g or more, an amino group-containing silane coupling agent, an organic acid, and an inorganic acid, which are specified as essential components in the present invention, the treatment liquid may be various as required. A material may be used.

  If the amino group-containing silane coupling agent is added dropwise or acid is added, heat of dilution or heat of reaction is generated, which may promote inappropriate polymerization between the silane coupling agents. Therefore, the liquid temperature of the solution is preferably controlled so as not to rise excessively. In particular, when a high-concentration treatment liquid is used, the rise in liquid temperature due to heat of reaction during hydrolysis is significant. When the liquid temperature rises, a gel-like material that is an excessive polymer of the amino group-containing silane coupling agent tends to be generated. In such a case, after dissolving an amino group-containing silane coupling agent in a polar solvent in advance, an organic acid and an inorganic acid are added to contain a polyvinylamine, polyallylamine, polydiallyldimethylammonium chloride, and a 5-membered ring amidine structure. It is preferable to adjust the treatment liquid by adding at least one hydrophilic resin selected from polymers.

"Inorganic pigments"
As an inorganic pigment used as a raw material for the modified inorganic pigment, those having an average particle diameter of 1 μm or less are preferable, and by using a fine pigment having a particle size of 500 nm or less, it is excellent in ink absorbability, transparency and gloss. Although a receiving layer is obtained, it is not limited to this. Types are not limited, but commercially available pigments such as silica, aluminosilicate, kaolin, clay, calcined clay, zinc oxide, tin oxide, aluminum hydroxide, boehmite, pseudoboehmite, alumina, calcium carbonate, satin white, aluminum silicate, smectite, Various inorganic pigments known in the field of general coated paper or ink jet recording material, such as magnesium silicate, magnesium carbonate, magnesium oxide, and diatomaceous earth, can be used. Among these fine pigments, silica, aluminum hydroxide, boehmite, pseudoboehmite, and alumina are particularly suitable because they have a large pore volume and excellent ink absorbability.

  In order to obtain a highly glossy and highly transparent ink-receiving layer, as a fine pigment, primary particles having an average particle diameter of 3 to 40 nm aggregate to form secondary particles having an average particle diameter of 500 nm or less. Is preferably used. In particular, the particle diameter of the secondary particles is preferably 8 to 400 nm, more preferably 10 to 300 nm. Such secondary particles have a large pore volume because of voids inside the secondary particles. Furthermore, since the voids between the secondary particles can also be used for ink absorption, the ink absorption capability is high. In addition, since the primary particles are sufficiently smaller than the wavelength of light, there are advantages in that the light scattering ability is small and the transparency of the ink receiving layer is high as compared with pigments not forming secondary particles. If the primary particle size or the secondary particle size of the pigment is too small, it becomes difficult to form voids that contribute to ink absorption, so that the ink absorbability of the ink receiving layer may be inferior. On the other hand, if the primary particle size or the secondary particle size is too large, the transparency of the ink receiving layer is lowered, and it may be difficult to obtain a high print density. On the other hand, if the secondary particle size is too large, not only the gloss of the ink receiving layer is lowered, but also the surface may be roughened or the powder may fall off. In addition, all the primary particle diameters of the pigment as used in the field of this invention are the particle diameters (Martin diameter) observed with the electron microscope (SEM and TEM) (refer to "fine particle handbook", Asakura Shoten, p52). The secondary particle diameter is a particle diameter measured by a dynamic light scattering method.

  In order to obtain an ink-receiving layer having a high ink absorption capacity, the fine pigment preferably has a high pore volume, but the fine pigment suitably used in the present invention has a pore volume of 0.4-2. 5 ml / g. Preferably it is 0.4-2.0 ml / g, More preferably, it is 0.6-1.9 ml / g, Most preferably, it is 0.7-1.8 ml / g. The pore volume is a value obtained using a specific surface area / pore distribution measuring device by a gas adsorption method. In the present invention, the pore volume is the total pore volume of pores having a pore diameter of 100 nm or less.

  The method for producing these fine pigments is not particularly limited, and as one of the means, there is a method obtained by pulverizing and dispersing a commercially available pigment (several μm) by applying a strong force by mechanical means. That is, it can be obtained by the breaking down method (a method of subdividing the bulk material). Examples of the mechanical means include mechanical techniques such as a high-speed rotary homogenizer, a pressure homogenizer, an ultrasonic homogenizer, a roll mill, a ball mill, a vibration mill, a bead mill, a sand grinder, and a jet mill. The fine pigment obtained may be colloidal or slurry. Other preferable methods for producing fine pigments include hydrolysis by metal alkoxides disclosed in JP-A-5-32413 and JP-A-7-76161.

Among the inorganic pigments as described above, silica is particularly preferable because of its large pore volume. Silica includes wet-process silica using alkali silicate as a raw material, vapor-phase process silica produced by a dry process that decomposes volatile silicon compounds such as silicon tetrachloride in a flame, and mesoporous silica. Is also preferable. Vapor phase silica is a very bulky silica that can easily be made into an aqueous dispersion, and when used in an ink-receiving layer, has excellent ink absorptivity, gloss, and coating transparency. Various products with different surface areas are commercially available. Therefore, gas phase method silica having an average primary particle diameter of 40 nm or less is most preferably used in the present invention. The average particle size of the aqueous dispersion varies depending on the method for producing the dispersion, but is in the range of about 100 nm to 900 nm. When the aqueous dispersion was dried to measure the specific surface area and pore volume by the nitrogen adsorption method is about a specific surface area of ^{50m 2} / ^g~400m 2 / g, a pore volume of 0.6ml / g~1.8ml / G.

The specific surface area by the "nitrogen adsorption method is described in JP 2001-354408 is at 300m ² / g~1000m ² / g, pore volume is 0.4ml / g~2.0ml / g A liquid in which silica particles are colloidally dispersed is used as a seed solution. After adding alkali to the seed solution, a feed solution consisting of at least one selected from an aqueous solution of active silicate and alkoxysilane is added to the seed solution little by little. to wherein the growing silica particles, specific surface area measured by the nitrogen adsorption method 100m ² / g~400m ² / g, average secondary particle diameter of 20 nm to 300 nm, and a pore volume of 0.5 ml / g Also preferably used is fine silica produced by the “method for producing a silica fine particle dispersion in which silica fine particles of up to 2.0 ml / g are colloidally dispersed”. Kill.

The method based on the condensation of active silicic acid disclosed in JP-A-2001-354408 can directly produce fine silica having the above particle diameter and pore volume without using mechanical means, and has a particle size distribution. Since it is narrow, it becomes a coating layer with good transparency and gloss, so that it can be preferably used. Here, the activated silicic acid refers to an aqueous silicic acid solution having a pH of 4 or less obtained by ion exchange treatment of an aqueous alkali metal silicate solution with a hydrogen cation exchange resin, for example. The SiO ₂ concentration is preferably 1 to 6% by mass, more preferably 2 to 5% by mass and an active silicic acid aqueous solution having a pH of 2 to 4. The alkali metal silicate may be a commercially available industrial product, and more preferably a sodium water glass having a SiO ₂ / M ₂ O (where M represents an alkali metal atom) molar ratio of about 2 to 4. It is preferable to use it. As a method for condensing active silicic acid, an aqueous solution of active silicic acid is added dropwise to hot water, or the aqueous solution of active silicic acid is heated to produce seed particles. Before the dispersion liquid precipitates or gels, an alkali is added. to stabilize the seed particles was added and then in terms of SiO ₂ with respect to SiO ₂ 1 mole contained the active silicic acid solution to the seed particle while maintaining the stable state from 0.001 to 0.2 mol / min It is preferable that each primary particle constituting the seed particle is grown by adding at a rate of 5%. The average secondary particle size is 1 μm or less, preferably 20 nm to 800 nm, and most preferably 30 nm to 700 nm. The average secondary particle diameter is a value measured by a particle size meter employing a dynamic light scattering method and analyzed by a cumulant method.

"Preparation method and conditions of modified inorganic pigment"
Means for modifying the surface of the inorganic pigment with a treatment liquid containing a hydrophilic resin having a cation equivalent of 4.0 meq / g or more, an amino group-containing silane coupling agent, an organic acid and an inorganic acid is not particularly limited. Depending on the characteristics of the material, the fine conditions may vary, but as a suitable example, the slurry aggregated and thickened by adding an inorganic pigment to the treatment liquid is mechanically dispersed and pulverized again, and the secondary particle size of the aggregate For adjusting the particle size to a desired particle diameter. Alternatively, inorganic pigments are gradually added and dispersed while giving a strong mechanical share to a treatment liquid containing a hydrophilic resin having a cation equivalent of 4.0 meq / g or more, an amino group-containing silane coupling agent, an organic acid and an inorganic acid. Can also be achieved. By passing through this means, a highly stable modified inorganic pigment dispersion can be obtained in which the cationic component of the treatment liquid is stabilized in a state of surrounding the inorganic pigment. The bond between the cation component and the inorganic pigment in the treatment liquid may be an ionic bond, a hydrogen bond, or a covalent bond, but regardless of the type of bond, the cation component and the inorganic pigment move together, and the potential of the modified inorganic pigment surface If (Zeta potential) is positive as a whole, reforming is achieved. When the zeta potential is +5 mV or more, preferably +10 mV to +60 mV, the ink fixing ability is excellent.
In order to obtain this effect sufficiently, if the amount of the hydrophilic polymer or the polymer containing an amino group and M—O—Si bond in the molecule is too small relative to the inorganic pigment, the periphery of the inorganic pigment can be stabilized. Since it cannot surround, there exists a possibility that the stability of the slurry and coating liquid after compounding may fall. On the other hand, if the amount is too large, the ink absorptivity may be hindered, and the quality such as light resistance and ozone resistance may be deteriorated. Specifically, the amount of a cationic component (the sum of a hydrophilic resin having a cation equivalent of 4.0 meq / g or more and an amino group-containing silane coupling agent) in a preferable treatment liquid with respect to 100 parts by mass of the inorganic pigment is 0.00. 5 to 30 parts by mass, more preferably 2 to 20 parts by mass, most preferably 5 to 15 parts by mass, but the optimum amount varies depending on the type (composition), molecular weight, and shape of the inorganic pigment or cation component. It is not limited to this range.

  In particular, when a high-concentration treatment liquid is used, the rise in liquid temperature due to heat of reaction during hydrolysis is significant. When the liquid temperature rises, a gel-like material that is an excessive polymer of the amino group-containing silane coupling agent tends to be generated. In such a case, after dissolving an amino group-containing silane coupling agent in a polar solvent in advance, an organic acid and an inorganic acid are added to contain a polyvinylamine, polyallylamine, polydiallyldimethylammonium chloride, and a 5-membered ring amidine structure. A method of producing an inorganic pigment dispersion in which at least one hydrophilic resin selected from polymers is added to obtain a treatment liquid and an inorganic pigment is dispersed in the treatment liquid is preferred. When this method is employed, a uniform surface-modified inorganic pigment is obtained. be able to.

When the treatment liquid of the present invention and an inorganic pigment are mixed, a certain degree of aggregation / thickening occurs. The aggregated and thickened mixed slurry is preferably mechanically shared (for example, dispersed and pulverized) from the viewpoint of gloss and print density of the obtained ink jet recording material. As the method, it can be achieved with a weak mechanical force such as a rotary homomixer until the average secondary particle size is about 1 μm, but a stronger mechanical force is applied to pulverize the average secondary particle size to 1 μm or less. It is preferable to obtain a uniform modified inorganic pigment, and a pressure dispersion method is desirable as a technique. A preferred specific example is a method of pulverizing a slurry mixture of raw material particles by applying a high pressure through a narrow orifice, and the processing pressure is preferably 10 to 350 MPa, more preferably 20 to 300 MPa, and still more preferably. 30 to 200 MPa. Good dispersion or pulverization can be achieved by the above high-pressure pulverization. This type of device is called a high pressure homogenizer. Furthermore, it is more preferable to use a system in which a high-speed slurry mixture that has passed through the orifice at high pressure collides with each other or is dispersed or pulverized by colliding with a fixed wall. In the method of opposing collision, the dispersion is pressurized and guided to the inlet side, the dispersion is branched into two passages, the flow path is further narrowed by the orifice, the flow velocity is accelerated, and the opposing collision occurs, thereby causing the particles to collide. Disperse and crush by colliding. As a material constituting the portion where the dispersion is accelerated or collided, diamond is preferably used for the reason of suppressing wear of the material.
As the high-pressure type homogenizer, a microfluidizer (manufactured by Microfluidics), an optimizer (manufactured by Sugino Machine Co., Ltd.), a homogenizer (manufactured by Sanwa Kikai Co., Ltd.), and a nanomizer (manufactured by Yoshida Kikai Kogyo Co., Ltd.) are used. In particular, a microfluidizer and a nanomizer are preferable as the opposing collision type homogenizer. The modified inorganic pigment thus subjected to the composite treatment is generally obtained as an aqueous dispersion (slurry or colloidal particles) having a solid content concentration of 5 to 40% by mass, more preferably 10 to 30% by mass.

[Inkjet recording medium]
The modified inorganic pigment prepared as described above can be suitably used as a material constituting the ink receiving layer of an ink jet recording material. An ink jet recording body generally has a configuration in which an ink receiving layer is provided on a support. The ink jet recording material to which the modified inorganic pigment is applied is shown below.

"Support"
As the support, various supports can be used as long as the coating layer serving as the ink receiving layer can be applied. For example, fine paper, art paper, coated paper, paperboard, cardboard, plastic film, non-woven fabric, metal foil, glass and the like can be exemplified.
In particular, when a support having an air permeability of less than 500 seconds / 100 ml is used, the so-called cast treatment in which the outermost layer of the recording material is dried by a heated gloss roll is possible, so that high gloss is obtained. Can be obtained. In addition, the air-permeable support has a relatively low specific gravity and is generally highly liquid-absorbing, and is suitable in that the support can also contribute to ink absorption. Because of expansion, there is a side surface where wrinkles and unevenness are likely to occur. When troubles occur in this respect, it is effective to apply an undercoat layer or a back layer. Moreover, a low air permeability or a non-air-permeable support body can be used conveniently by the point that it is not necessary to worry about these.

In the present invention, the low air-permeable or non-air-permeable support means that the Oken type air permeability is 500 seconds / 100 ml or more, preferably 800 seconds / 100 ml or more, more preferably 1000 seconds / 100 ml or more. Means support. When such a support is used, it is possible to prevent water vapor and moisture from penetrating into the support itself, and it is possible to easily obtain an ink jet recording body having a photographic texture with reduced cockling and the like.
For example, a so-called synthetic paper, cellophane represented by YUPO (trade name: manufactured by YUPO Corporation), which is a so-called resin-coated paper in which polyethylene resin is coated on both sides of a paper support, and polypropylene is drawn and specially processed. (Registered trademark), polyethylene, polypropylene, soft polyvinyl chloride, hard polyvinyl chloride, polyester (such as PET), films such as polystyrene, metallized paper, and papers with controlled air permeability. Of these, the use of resin-coated paper, synthetic paper, and film is preferred.

  In particular, a resin-coated paper obtained by coating polyethylene on which the titanium oxide is kneaded on the paper surface is preferably used because the finished appearance is equivalent to that of a photographic printing paper. 3-50 micrometers is preferable and, as for the thickness of a polyethylene coating layer, 5-30 micrometers is more preferable. When the thickness of the polyethylene coating layer is less than 3 μm, defects such as holes in the polyethylene resin tend to increase during resin coating, and there are many cases where it is difficult to control the thickness, and smoothness is difficult to obtain. Conversely, if it exceeds 50 μm, the effect obtained is small and uneconomical for an increase in cost. In order to enhance the adhesion of an undercoat layer or ink receiving layer described later, it is preferable to subject the surface of the coating layer to corona discharge treatment or to provide a subcoat layer such as gelatin.

  As the paper support used for the resin-coated paper, one manufactured using wood pulp as a main material is used. As the wood pulp, various chemical pulps, mechanical pulps, regenerated pulps and the like can be used as appropriate, and these pulps can be adjusted in the beating degree by a beating machine in order to adjust paper strength, smoothness, papermaking suitability, and the like. The beating degree is not particularly limited, but generally about 250 to 550 ml (CSF: JIS-P-8121) is a preferable range. Also, chlorine-free pulp such as so-called ECF and TCF pulp can be preferably used. Moreover, a pigment can be added as needed. As the pigment, talc, calcium carbonate, clay, kaolin, calcined kaolin, silica, zeolite and the like are preferably used. Opacity and smoothness can be increased by adding a pigment, but if added excessively, paper strength may be reduced, and the amount of pigment added is preferably about 1 to 20% by mass with respect to wood pulp.

  In addition, if a plastic film with excellent transparency such as polyethylene terephthalate, polyvinyl chloride, polycarbonate, polyimide, cellulose triacetate, cellulose diacetate, polyethylene, polypropylene is used as a support, light transmission such as a back print or an OHP sheet is possible. An ink jet recording material that can be used as a recording medium can be produced. Since the ink receiving layer obtained in the present invention is highly transparent, it can be suitably used for these media.

The thickness of the support is preferably 50 to 500 μm in consideration of the paper passing property of the printer. In particular, in the case of a water-absorbing support, if the support is too thin, there is a concern that the strength and dimensional stability when wet will be lowered, so a relatively thick 100 to 500 μm is desirable. In addition, a back layer can be provided on the side of the support opposite to the ink receiving layer in order to suppress curling of the ink jet recording body and to improve transportability. In particular, when a support having high air permeability or high water absorption is used, it is desirable to coat the back surface layer so that the touch feeling can be brought closer to the silver salt photograph. The structure of the back surface layer and the accompanying easy adhesion treatment of the back surface of the support sheet can be selected depending on the application, and are not particularly limited. However, in view of coating property and cost, the pigment and the hydrophilic resin It is preferable to provide a back surface layer containing as a main component. A support provided with a resin coating of resin-coated paper only on the back side instead of the back layer is also preferably used. However, if the water absorption of the back layer is too high, it is not preferable because the recording medium laminated after printing is stuck or sticky.
Furthermore, assuming double-sided printing, a coating layer including an ink-receiving layer may be provided on both sides, and the back surface may be subjected to adhesive processing so as to correspond to a label or seal application.

"Undercoat"
In the ink jet recording material, an undercoat layer containing a pigment and a binder may be formed between the support and the ink receiving layer. The undercoat layer can be provided with functions such as adjusting the dimensional stability, smoothness, and color tone of the support, and quickly absorbing the solvent in the inkjet ink component. A colorant, that is, a dye in the ink-jet ink component that could not be fixed by the ink receiving layer may be fixed. In particular, when a water-absorbing support is used, it is desirable to coat an undercoat layer from the viewpoint of wet strength and dimensional stability as described above.

  Examples of the pigment used for the undercoat layer include transparent or white pigments such as colloidal silica, amorphous silica, alumina, aluminum hydroxide, magnesium carbonate, calcium carbonate, kaolin, and calcined kaolin. Pigments used in the ink receiving layer and the gloss layer such as the modified inorganic pigment of the present invention described later can also be used. Of these, an especially preferred pigment is amorphous silica.

  When amorphous silica is used, the amorphous silica preferably has an average primary particle diameter of 3 to 70 nm and an average secondary particle diameter of 20 μm or less, an average primary particle diameter of 10 to 40 nm, and an average of 2 Those having a secondary particle size of 15 μm or less are more preferred. The average secondary particle diameter of the amorphous silica used for the undercoat layer is preferably larger than the average secondary particle diameter of the amorphous silica used for the ink receiving layer. When the average secondary particle diameter of the amorphous silica used for the undercoat layer is smaller than the average secondary particle diameter of the amorphous silica used for the ink receiving layer, the ink absorbability may be lowered.

The binder resin for the undercoat layer includes proteins such as casein, gelatin and soybean protein, various starches such as starch, oxidized starch and processed starch, and modified polyvinyl alcohols such as polyvinyl alcohol, cationic polyvinyl alcohol and silyl-modified polyvinyl alcohol. Polyvinyl alcohols containing, cellulose derivatives such as carboxymethyl cellulose and methyl cellulose, styrene-butadiene copolymer, conjugated diene polymer latex of methyl methacrylate-butadiene copolymer, acrylic polymer latex, ethylene-vinyl acetate copolymer, etc. Conventionally known binders generally used for coated paper, such as vinyl polymer latex, are used singly or in combination of several kinds.
The blending ratio of the pigment and binder in the undercoat layer is generally adjusted in the range of 1 to 100 parts by weight, preferably 2 to 50 parts by weight with respect to 100 parts by weight of the pigment.

  A cationic compound that is an ink fixing agent is added to the undercoat layer as necessary in order to catch ink penetrating from the ink receiving layer, fix the dye, impart water resistance, and improve the recording density. be able to.

  The cationic compound to be added may be the modified inorganic pigment of the present invention or the processing liquid that is a raw material thereof, but is a general organic cation resin or inorganic fixing agent exemplified as a modified material of the inorganic pigment. May be. However, as described above, since the cationic resin may impair image storage stability other than fixing, it is desirable to suppress the amount used.

  In addition to the above components, the coating liquid for forming the undercoat layer further includes a dispersant, a thickener, an antifoaming agent, an antistatic agent, an antiseptic, a fluorescent dye used in the production of general coated paper. Various auxiliary agents such as a colorant are appropriately added.

The coating amount of the undercoat layer is about 0.5 to 30 g / m ² and can be formed by various known coating apparatuses such as a blade coater, an air knife coater, a roll coater, a bar coater, a gravure coater, a die coater, and a curtain coater. . In particular, the air knife coater is preferably used because it can handle a wide range of coating liquid properties and coating amounts. In addition, a die coater and a curtain coater are excellent in uniformity of coating amount, and are therefore preferable coating methods particularly for glossy ink jet recording materials for the purpose of high-definition recording.

"Ink receiving layer"
The ink receiving layer was modified according to the present invention with a treatment liquid containing a hydrophilic resin having a cation equivalent of 4.0 meq / g or more, an amino group-containing silane coupling agent, an organic acid and an inorganic acid. The coating liquid containing the modified inorganic pigment characterized by this can be formed on the support or the undercoat layer. The modified inorganic pigment exhibits its performance to the maximum by using it as a main component of the porous ink receiving layer, which is essential for ink absorption and fixing, in the inkjet recording medium.
The other materials for forming the porous ink receiving layer are shown below.

  The porous ink receiving layer includes a fine pigment and a binder resin required for film formation as essential components. In the present invention, a modified inorganic pigment is used as the fine pigment, but inorganic pigments exemplified as the raw material of the modified inorganic pigment, organic pigments such as styrene-based plastic pigments, urea resin-based plastic pigments, and benzoguanamine-based plastic pigments, Various pigments known in the field of general coated paper or ink jet recording material may be mixed. However, it is most desirable to use the modified inorganic pigment alone from the viewpoint of the quality of the recording medium and the stability of the coating solution, and even when other pigments are mixed, the amount added does not interfere with the quality of the modified inorganic pigment. The range is good. Further, various pigments may be pretreated before preparing the coating liquid.

  The binder resin component of the ink receiving layer is not particularly limited, but various resins exemplified as the material for the undercoat layer may be used singly or in combination.

  Among these, polyvinyl alcohol or a derivative thereof is most preferably used from the viewpoints of miscibility with the pigment as the main component, coating suitability, and quality of the obtained ink jet recording material. The degree of saponification is not particularly limited and can be appropriately used in the range of 70 to 99.9 mol%. However, if the degree of saponification is too low, the hydrophilicity is lowered, and if too high, there is a possibility of fibrillation, etc. Preferably it is 75-99.9%, More preferably, it is 78-99.8%. Also, the polymerization degree can be suitably used at 200 to 4500, but if it is too low, the coating liquid viscosity may be too low or cracking may not be suppressed, and if it is too high, the coating liquid viscosity is high. Since it becomes too much, Preferably it is 1000 or more, More preferably, it is 1000-4500.

  In order to change the color tone with time after printing, it is also effective to use a resin having a high affinity with the hydrophilic high-boiling solvent contained in the ink alone or in combination. The hydrophilic high-boiling solvents contained in the ink include glycerin, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, diethylene glycol monomethyl ether, 2-pyrrolidone, thiodiglycol, triethylene glycol mono Examples of resins having high affinity with these solvents include butyl ether, 1,5-pentanediol, etc., but include, but are not limited to, polyvinylpyrrolidone, polyacryloylmorpholine, polyhydroxyalkyl acrylate, and hydroxypropylcellulose. Is not to be done.

  Since the modified inorganic pigment used in the present invention has a high ink fixing ability, it is basically unnecessary to use another ink fixing agent in combination. However, within the range that does not interfere with the performance of the modified inorganic pigment with intentions other than fixing ability such as color tone adjustment, as a cationic compound, a general cationic resin exemplified as a modified material of inorganic pigment, or an emulsion type These may be blended as necessary, alone or in combination of several inorganic fixing agents such as cationic resins and polyvalent metal salt compounds. However, in this case, the amount of the cationic compound to be added is the minimum amount, and the addition means is to multilayer the ink receiving layer or laminate the ink fixing agent separately in order to suppress the opacification of the coating layer to the maximum. A configuration such as coating is desirable.

Among the inorganic fixing agents, zirconium compounds, titanium compounds, aluminum compounds, and zinc compounds can be preferably used from the viewpoint of ink fixing ability. In particular, a zirconium compound is particularly preferable because it has a good color tone when continuously printed in a printing density of an ink jet recording medium and in a constant temperature and high humidity environment.
Zirconium chloride (ZrCl ₄ ), zirconium oxychloride (ZrOCl ₂ · nH ₂ O), zirconium sulfate (Zr (SO ₄ ) ₂ · nH ₂ O), zirconium oxysulfate (ZrOSO ₄ · nH ₂ O) , Zirconium nitrate (Zr (NO ₃ ) ₄ .nH ₂ O), zirconium oxynitrate (ZrO (NO ₃ ) ₂ .nH ₂ O), zirconium diacetate (Zr (CH ₃ COO) ₂ ), zirconium tetraacetate (Zr) In addition to various zirconium salts such as (CH ₃ COO) ₄ ), zirconium oxyacetate (ZrO (CH ₃ COO) ₂ ), ammonium zirconium carbonate ((NH ₄ ) ₂ ZrO (CO ₃ ) ₂ ), zirconium alkoxides and the like Illustrated. However, among the zirconium compounds, zirconium alkoxides are very fast in hydrolysis and polymerization reaction, so the reaction is difficult to control. In particular, as the number of alkoxyl groups increases, coarse zirconium hydroxide precipitates due to rapid polymerization. Be careful because it tends to be easy to do. In view of the solubility in water, the most preferred solvent of the present invention, the pH of the compound itself, the cost, and the property of exhibiting a cationic property that bears the ink fixing ability when polymerized, etc., there is a unit of ZrO in the chemical formula. Zirconium salt, that is, oxyzirconium salt is preferred, and among these, zirconium oxychloride (also known as: zirconyl chloride, zirconium oxide chloride) is most preferred. This zirconium oxychloride can be purchased, for example, from Daiichi Rare Element Chemical Co., Ltd. as product names: zirconium oxychloride, zircozole ZC, zircozole ZC-20. Moreover, you may utilize the commercially available zirconium compound (For example, brand name: Zircosol ZC-2, the 1st rare element chemical industry company make) which raised content of a polynuclear ion.

On the other hand, aluminum compounds include aluminum chloride, tetrachloroaluminate (eg, sodium salt), aluminum bromide, tetrabromoaluminate (eg, potassium salt), aluminum iodide, aluminate (eg, Sodium salt, potassium salt, calcium salt, etc.), aluminum fluoride, hexafluoroaluminic acid (eg, potassium salt), aluminum sulfate, basic aluminum sulfate, potassium aluminum sulfate (alum), ammonium aluminum sulfate (ammonium alum), sulfuric acid Sodium aluminum, aluminum phosphate, aluminum nitrate, aluminum hydrogen phosphate, aluminum carbonate, polysulfuric acid aluminum silicate, aluminum formate, aluminum acetate, aluminum lactate, aluminum oxalate In addition to the various aluminum salts and the like, aluminum alkoxides and the like. Moreover, like a zirconium compound, the high molecular weight product (for example, the product made from Taki Chemical Co., Ltd., polyaluminum chloride: brand name PAC, highly basic aluminum chloride: Trade name tachyvine, highly basic aluminum lactate: trade name taxanelam, etc.) can also be preferably used.
Titanium compounds include titanium tetrachloride, titanium sulfate, basic titanium lactate, titanium lactate ammonium salt, various titanium salts, titanium alkoxides, etc., and zinc compounds include zinc chloride, zinc ammonium chloride, zinc sulfate, Various zinc salts such as zinc acetate, zinc nitrate, zinc pyrophosphate, zinc citrate, and zinc lactate are exemplified.
The above metal compounds may be used singly or in combination of two or more, and metal compounds other than the exemplified compounds may be used.

  The ink receiving layer of the present invention is preferably adjusted so as to be porous, specifically, the pore volume is in the range of 0.2 to 2.0 ml / g. It can be adjusted within this range by selecting the pore volume of the fine pigment and by appropriately adjusting the amount of the hydrophilic resin added. When the pore volume is less than 0.2 ml / g, the ink cannot be absorbed unless the coating amount is increased, so that the manufacturing cost of the ink jet recording body is increased. On the other hand, a pore volume exceeding 2.0 ml / g is not preferable because the mechanical strength of the ink receiving layer is lowered, and the ink receiving layer is easily scratched, peeled off or cracked. The pore volume of the present invention is the total pore volume of pores having a pore diameter of 100 nm or less.

  The suitable solid content concentration of the aqueous coating liquid used in the present invention varies greatly depending on the composition of the coating liquid, but it is preferably higher in the range in which the aqueous coating liquid can be stably and coated. This is because the higher the concentration of the aqueous coating liquid, the lighter the drying load. The solid content concentration of the aqueous coating liquid is preferably 3 to 40% by mass, more preferably 5 to 25% by mass.

  In addition to the main component, the coating properties of the aqueous coating liquid are not significantly deteriorated, the pores necessary for ink absorption are maintained, and the water resistance of the ink receiving layer is not significantly reduced. Other components can also be added to the ink receiving layer. Examples thereof include fluorescent whitening agents that have the effect of increasing the whiteness of ink jet recording materials and boron compounds such as boric acid and / or borates that have the effect of suppressing cracks in porous receptor layers that are prone to cracking. .

Examples of boric acid include orthoboric acid, metaboric acid, hypoboric acid, tetraboric acid, and pentaboric acid. Moreover, these sodium salt, potassium salt, and ammonium salt may be sufficient. Among these, orthoboric acid and disodium tetraborate are preferable. Incidentally, the sodium salt of boric acid is often referred to as borax, its composition is usually _{Na 2 B 4 O 7 · 10H} 2 O.

  The addition means is not only internally added to the aqueous coating liquid in advance as described above, but also is applied to the support or the undercoat layer before applying the ink receiving layer, or the ink is applied as long as the coated surface is not disturbed. It may be laminated on the aqueous coating liquid coating layer after drying of the receiving layer and before drying, and is not particularly limited thereto. In terms of uniform mixing, a method of internally adding to the aqueous coating liquid is preferable. When the boron compound is added by a method other than the internal addition to the aqueous coating liquid, the boron compound is internally added to the undercoat layer for the purpose of diffusion to the ink receiving layer, or the solution containing the boron compound and the ink receiving layer are added. Alternatively, the aqueous coating solution may be applied by wet-on-wet, or a solution containing a boron compound may be applied to the aqueous coating solution using a method such as lamination / spraying. The type of the solvent for dissolving the boron compound is not particularly limited, but water is most preferable from the viewpoints of cost and handling.

  A surfactant may be added to improve the workability during coating by mixing an antifoaming agent, or to improve the wettability of the support and obtain a uniform ink-receiving layer. High pore volume fine pigment-based coating liquids preferably used in the present invention tend to increase in viscosity and increase in thixotropy with time and often have poor coating suitability. In that case, it is preferable to add a certain amount of a surfactant to the coating solution because the coating suitability is improved. The addition amount is not particularly specified, but 0.001 to 5 parts by mass, and more preferably 0.01 to 1 part by mass is suitable for 100 parts by mass of the fine pigment that is the main component of the coating liquid. . If the addition amount of the surfactant is too small, the above-mentioned effect of improving the coating solution cannot be sufficiently obtained, which is inappropriate. On the other hand, if the amount added is too large, problems such as blocking and transfer to the back surface caused by the excessive amount of surfactant oozing out from the coated film become unsuitable.

The surfactant to be added may be any of an anionic surfactant, a cationic surfactant, and a nonionic surfactant.
Examples of anionic surfactants include sulfate ester salts, sulfonate salts, phosphate ester salts, and the like. Examples of the cationic surfactant include amine salt type and quaternary ammonium salt type. Nonionic surfactants include, for example, acetylene glycols, polyethylene glycols (higher alcohol ethylene oxide adducts, fatty acid ethylene oxide adducts, alkylphenol ethylene oxide adducts, polypropylene glycol ethylene oxide adducts, higher aliphatic amines and fatty acids. Amide ethylene oxide adducts), polyhydric alcohols (fatty acid esters of glycerin and pentaerythritol, fatty acid esters of sorbitol and sorbitan, fatty acid esters of sucrose, ethylene oxide adducts of polyhydric alcohols, fatty acid alkanolamides, etc.) Can be mentioned.

  Among the above surfactants, nonionic surfactants are preferred because of their high affinity with ink for ink jet printers. Furthermore, among nonionic surfactants, acetylene glycol surfactants are preferred. The acetylene glycol-based surfactant is nonionic and has a very strong polarity because oxygen atoms are bonded to adjacent carbon atoms that form an acetylenic triple bond in the molecule. Therefore, even when added in a small amount, the surface activity effect is high, and the wettability of the aqueous coating liquid with respect to the support can be improved. In general, a surfactant has a strong bubble forming property, which causes a problem of foaming. However, an acetylene glycol surfactant has a defoaming property and can suppress foaming. Among these, an addition reaction product of an alkynylene glycol compound and ethylene oxide is preferable.

  In addition, various additives may be added for the purpose of improving the quality of the ink jet recording material. Specifically, coloring dyes or pigments for color tone preparation, image preservability improving agents such as light stabilizers and ultraviolet absorbers, and the like are not limited thereto. In particular, it is preferable to add a blue color pigment to the aqueous coating liquid as a color tone adjusting agent together with the fluorescent whitening agent, because the whiteness of the recording medium is visually emphasized by a synergistic effect.

  As a method for adding these additives, they may be mixed in advance with the modified inorganic pigment sol, or may be mixed during preparation of the coating liquid. Moreover, after forming a coating layer first, you may add the solution containing an additive later by methods, such as top-coating, spraying, and impregnating with a well-known coating means.

The coating amount of the ink receiving layer is preferably about 1~60g / ^{m 2} as the mass after drying, more preferably about 3 to 50 g / ^{m 2.} Here, if it is less than 1 g / m ² , ink absorption tends to be insufficient, and if it is more than 60 g / m ² , curling tends to occur and the cost increases, which is not preferable. Two or more ink receiving layers may be formed. When it has two or more layers, the composition of the coating liquid may be different.

  The ink-receiving layer is coated by using the above-described known coating apparatus for the aqueous coating liquid for the receiving layer, such as a bar coater, a roll coater, a blade coater, an air knife coater, a gravure coater, a die coater, or a curtain coater. Yes, but not limited to. Moreover, you may implement multilayer coating using simultaneous multilayer coating apparatuses, such as a multilayer slot die coater, a multilayer slide die coater, a multilayer curtain coater. The undercoat layer and the ink receiving layer can be simultaneously applied in multiple layers.

  In addition, the active energy ray-curable material is mixed in advance with the coating layer to be the ink receiving layer, and the coating layer is gelated by irradiating the active energy ray to the coating layer before drying, You may suppress the crack of the coating layer which is easy to produce. The active energy ray to be used is not particularly limited, and examples thereof include α rays, β rays, γ rays, X rays, ultraviolet rays, and electron beams. However, it is preferable to use ultraviolet rays and electron beams which are easy to handle and are widely used. For ultraviolet rays, it is necessary to use a photopolymerization initiator or a specific hydrophilic resin having an active group, but it is preferable that the irradiation equipment is inexpensive. Alternatively, an electron beam that can form a hydrogel with many of general-purpose hydrophilic resins as described above can be most suitably used without adding an initiator or the like to the aqueous coating liquid. In addition, when an air-permeable support is used, the ink receiving layer can be subjected to a casting process in which the ink receiving layer is pressed against a heated gloss roll and dried while the ink receiving layer is in a wet state.

"Glossy layer formation"
The ink jet recording material of the present invention may form a gloss layer containing a fine pigment as a main component, if necessary. In the case where the cost is important or the gloss sufficient for the application is obtained, it is not necessary to form the gloss layer. However, in the case of photographic printing, it is preferable to coat a glossy layer. The glossy layer may be formed during the drying of the porous ink receiving layer or after the drying. Further, simultaneous multilayer coating with the ink receiving layer may be performed.

  The coating liquid for glossy layer contains arbitrary other components such as a fine pigment, a binder resin, and a cationic compound. The coating solution for forming the gloss layer is prepared by dispersing these components in a dispersion medium.

  Examples of the fine pigment used in the gloss layer include colloidal silica, amorphous silica, alumina, boehmite, aluminum hydroxide, magnesium carbonate, calcium carbonate, kaolin, calcined kaolin, and other transparent or white pigments. It is not limited and organic pigments can also be used. The modified inorganic pigment of the present invention may be used. Among these, colloidal silica, alumina, or amorphous silica is preferable because glossiness is particularly improved. When using colloidal silica or alumina, the average primary particle size is preferably 5 to 100 nm, more preferably 10 to 80 nm. More preferably, it is 20-70 nm. When the average particle diameter is less than 5 nm, the ink absorbability may be reduced, and when the average particle diameter exceeds 100 nm, the transparency tends to decrease and the print density tends to decrease.

  When amorphous silica is used, one having an average primary particle diameter of 5 to 100 nm, more preferably 5 to 40 nm is used. Amorphous silica preferably has an average secondary particle diameter of 1 μm or less, more preferably 10 to 700 nm.

When the binder resin component is added in order to enhance the adhesion of the fine pigment, the type is not particularly limited, but the above-described various water-soluble resins and emulsion type hydrophilic resins are preferably used. When using an emulsion type hydrophilic resin, the average particle size is preferably in the range of 20 to 150 nm. If the average particle size is less than 20 nm, the ink absorbency may be reduced, and if it exceeds 150 nm, the glossiness is reduced. There is a case. These glass transition temperatures are preferably in the range of 50 to 150 ° C. When the glass transition temperature is lower than 50 ° C., the gloss layer is excessively formed at the time of drying, and the porosity of the gloss layer is lowered and the ink absorbability may be lowered. When the temperature is higher than 150 ° C., film formation is insufficient, and gloss and strength may be insufficient.
In addition to the above, the gloss layer includes various dispersants and thickeners used in the production of organic and inorganic coarse particles and generally coated paper to prevent paper feeding suitability and blocking. Various auxiliary agents such as an antifoaming agent, a colorant, an antistatic agent, an antiseptic and a preservative may be added as appropriate.

The coating amount of the glossy layer is preferably 0.01 to 10 g / ^{m 2} as dry mass, more preferably 0.1-5 g / ^{m 2,} more preferably 0.3 to 3 g / ^{m 2.} When the coating amount is less than 0.01 g / m ² , it is advantageous in terms of ink absorbability and recording density, but it is difficult to form a sufficient gloss layer, so that the glossiness tends to be low. On the other hand, when the coating amount exceeds 10 g / m ² , the glossiness is easily obtained, but the ink absorbability and the recording density tend to decrease.
The thickness of the gloss layer varies greatly depending on the pore state of the ink receiving layer. Therefore, it is difficult to unconditionally define the thickness of the gloss layer, but it is preferably 5 nm to 5 μm, more preferably 10 nm to 3 μm, and most preferably 20 nm to 1 μm. In order to obtain sufficient gloss on the surface of the coating layer, it is most desirable that the gloss layer coating liquid completely covers the surface of the ink receiving layer while maintaining pores. Is equal to the diameter of the fine pigment used in the glossy layer coating solution. On the other hand, when the thickness of the glossy layer exceeds 5 μm, it is not preferable because there is a possibility that the ink absorbability and the strength of the coating film may be hindered.

The gloss layer can be produced by a known coating apparatus similar to the ink receiving layer. Multi-layer coating may be performed simultaneously with the ink receiving layer. Further, in order to further improve the glossiness, in the case of a gas-permeable support, a method of drying using a heated gloss roll (so-called casting treatment) is used, and in the case of a low-gas permeability or non-air-permeable support, WO2003 / It is possible to employ a method disclosed in Japanese Patent No. 039881 and the like, in which coating is performed while applying pressure at the nip portion between a heated gloss roll and a press roll, and drying is performed in the next step.
In addition, a release agent can be added to the coating liquid for forming the gloss layer in order to smoothly and stably peel the surface of the formed coating liquid layer from the gloss roll.
Release agents include fatty acids such as stearic acid, oleic acid, and palmitic acid, and salts thereof such as sodium, potassium, calcium, zinc, ammonium, stearic acid amide, ethylene bis stearic acid amide, and methylene bis stearic acid amide. Fatty acid amides such as, aliphatic hydrocarbons such as microcrystalline wax, paraffin wax and polyethylene wax, higher alcohols such as cetyl alcohol and stearyl alcohol, fats and oils such as funnel oil and lecithin, lipids, fluorine-containing surface activity Examples thereof include various surfactants such as agents, and fluorine-based polymers such as tetrafluoroethylene polymer and ethylene-tetrafluoroethylene polymer.

  Of these, aliphatic hydrocarbons or derivatives or modified products thereof, fatty acids or salts thereof, and lipids are particularly preferable. Among them, polyethylene wax is used as the aliphatic hydrocarbon, stearic acid or oleic acid is used as the fatty acid, and lipids are used. More preferably, lecithin is used.

  The surface temperature of the gloss roll is preferably in the range of 40 to 130 ° C., more preferably in the range of 70 to 120 ° C., more preferably in the range of 70 to 120 ° C., from the operational properties such as drying conditions, the adhesion to the ink receiving layer, and the gloss of the gloss layer surface. A range of 110 ° C. is more preferred. When the surface temperature of the gloss roll is less than 40 ° C., the coating strength due to insufficient indentation of the pigment may decrease or the gloss may decrease. When the surface temperature exceeds 130 ° C., the coating may crack. .

  Note that, instead of the fine pigment in the gloss layer, a pigment having an average particle diameter of more than 1 μm can be used as a matting agent to control the gloss low.

  Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples. Moreover, unless otherwise indicated, the part and% in an example are a mass part and the mass%, respectively.

"Creation of support A (paper base)"
Conifer bleached kraft pulp (NBKP) beaten to CSF (JIS P-8121) to 250 ml and hardwood bleached kraft pulp (LBKP) beaten to CSF to 250 ml are mixed at a mass ratio of 2: 8, and the concentration is 0. A 5% pulp slurry was prepared. In this pulp slurry, cationized starch 2.0%, alkyl ketene dimer 0.4%, anionized polyacrylamide resin 0.1% and polyamide polyamine epichlorohydrin resin 0.7% are added to the pulp dry weight. The mixture was sufficiently stirred and dispersed.
The pulp slurry having the above composition was made with a long net machine, and passed through a dryer, a size press, and a machine calendar to produce a base paper having a basis weight of 180 g / m ² and a density of 1.0 g / cm ³ . The size press solution used in the size press step was prepared by mixing carboxyl-modified polyvinyl alcohol and sodium chloride at a mass ratio of 2: 1, adding this to water and dissolving it by heating, and adjusting the concentration to 5%. A total of 25 ml / m ^{2 of} this size press solution was applied to both sides of the paper to obtain a support A (air permeability: 1000 seconds).

"Creation of support B (RC paper base)"
The following polyolefin resin composition 1 that has been subjected to corona discharge treatment on both sides of the base paper of the support A and then mixed and dispersed by a Banbury mixer is applied to the felt surface side of the support A so that the coating amount is 25 g / m ^2. The polyolefin resin composition 2 was applied to the wire side of the support A with a melt extruder (melting temperature: 320 ° C.) having a T-type die so that the coating amount was 20 g / m ^2, and felt. The surface side is cooled and solidified with a mirror surface cooling roll and the wire surface side is cooled with a rough surface cooling roll, smoothness (Oken type, J.TAPPI No. 5B) is 6000 seconds, and opacity (JIS P8138) is 93%. The resin was coated. Then, after corona discharge treatment was performed again on the side coated with the polyolefin resin composition 1, a 1% hot aqueous solution of commercially available photographic gelatin (manufactured by Miyagi Chemical Co., Ltd., product name: P-487) was reduced to a dry mass of 0.00. Coating was carried out to 1 g / m ² and drying with hot air at 60 ° C. gave Support B.

(Polyolefin resin composition 1)
35 parts long chain low density polyethylene resin (density 0.926 g / cm ³ , melt index 20 g / 10 min), 50 parts low density polyethylene resin (density 0.919 g / cm ³ , melt index 2 g / 10 min), anatase Type titanium dioxide (trade name: A-220, manufactured by Ishihara Sangyo Co., Ltd.) 15 parts, zinc stearate 0.1 part, antioxidant (trade name: Irganox 1010, manufactured by Ciba Geigy) 0.03 parts, ultramarine (trade name) : Aoguchi Ultramarine NO.2000, manufactured by Daiichi Kasei Co., Ltd.) 0.09 part, fluorescent whitening agent (trade name: UVITEX OB, manufactured by Ciba Specialty Chemicals Co., Ltd.) 0.3 part, and polyolefin resin composition 1 It was.

(Polyolefin resin composition 2)
65 parts of high-density polyethylene resin (density 0.954 g / cm ³ , melt index 20 g / 10 minutes) and 35 parts of low-density polyethylene resin (density 0.919 g / cm ³ , melt index 2 g / 10 minutes) are melt mixed. A polyolefin resin composition 2 was obtained.
Example 1
(Preparation of modified inorganic pigment sol)
3-aminopropyltrimethoxysilane (amino group-containing silane manufactured by Shin-Etsu Chemical Co., Ltd.) was added to 368.7 g of ion-exchanged water stirred at 2000 rpm with a commercially available high-speed disperser (Primix Corporation, TK Robotics). Coupling agent, product number: LS-1420) 3.3 g was added, and after sufficient stirring, 18.5 g of 10% formic acid aqueous solution and 4.6 g of 10% hydrochloric acid aqueous solution were added dropwise. After stirring for 10 minutes, 12.3 g of a polyallylamine aqueous solution (PAA-15C manufactured by Nittobo Co., Ltd., average molecular weight≈15000, solid content concentration 15%, cation equivalent = 17.5 meq / g) was added, and stirring was continued for 10 minutes. did. Next, 92.5 g of a commercially available specific surface area of 200 m ² / g gas phase method silica (trade name: Leorociol QS-102, average primary particle size 12 nm, manufactured by Tokuyama Corporation) was gradually added, and the stirring speed of the high-speed disperser was set to 15000 rpm. The mixture was stirred for 20 minutes to prepare a modified inorganic pigment sol A having a solid content concentration of 20%.
The resulting modified inorganic pigment had a pore volume of 1.5 ml / g and an average secondary particle size of 165 nm. The average secondary particle diameter and pore volume were measured as follows.

"Method for measuring average secondary particle size of modified inorganic pigments"
100 ml of the modified inorganic pigment sol A was placed in a 500 ml stainless steel cup, and dispersed (3,000 rpm, 5 minutes) using the above-described high-speed disperser to disperse the tertiary particles in the aqueous dispersion. The dispersion after treatment is sufficiently diluted with distilled water to obtain a sample solution, and averaged using a laser particle size meter by dynamic light scattering method (manufactured by Otsuka Electronics, FPAR-1000, measurable range: 3 nm to 5 μm). Secondary particle size was measured. As the average secondary particle size, a value calculated from an analysis using a cumulant method was used.

"Method for measuring pore volume of modified inorganic pigments"
The modified inorganic pigment sol A was dried as it was at 105 ° C. and measured after vacuum degassing at 200 ° C. for 2 hours as a pretreatment using a nitrogen gas adsorption specific surface area / pore distribution measuring device (SA3100 plus type manufactured by Coulter). did. As the pore volume, the value of the total pore volume (nitrogen relative pressure 0.9814) having a pore diameter of 100 nm or less was used.

(Manufacture of ink jet recording material)
5. 60 g of the above-described modified inorganic pigment sol A, 6.1 g of ion-exchanged water, 0.5 g of boric acid, 0.1% aqueous solution of acetylene glycol surfactant (trade name: Orphine E1004, manufactured by Nissin Chemical Industry Co., Ltd.) After mixing 00 g, 26.7 g of 9% aqueous solution of partially saponified polyvinyl alcohol (trade name: PVA-224, polymerization degree = 2400, saponification degree = about 88%, manufactured by Kuraray Co., Ltd.) was mixed, and the solid content concentration was 15%. A coating solution was prepared.
On the side of the support B on which the polyolefin resin composition 1 was laminated, the coating solution was applied with a die coater so that the coating amount was 24 g / m ² in dry mass, and dried with hot air at 110 ° C. for 10 minutes. An ink jet recording material was obtained.

Example 2
To 370.3 g of ion-exchanged water stirred at 2000 rpm, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane (amino group-containing silane coupling agent manufactured by Shin-Etsu Chemical Co., Ltd., product number: LS-2480) 3 .3 g was added, and after sufficient stirring, 16.7 g of 10% aqueous acetic acid solution and 4.6 g of 10% aqueous hydrochloric acid solution were added dropwise. After stirring for 10 minutes, 12.4 g of a polyallylamine aqueous solution (PAA-15C manufactured by Nittobo Co., Ltd., average molecular weight≈15000, solid content concentration 15%, cation equivalent = 17.5 meq / g) was added, and further stirred for 10 minutes. . Then, the same procedure as in Example 1 was conducted except that 92.7 g of a commercially available specific surface area of 200 m ² / g gas phase method silica (trade name: Leorociol QS-102, average primary particle size 12 nm, manufactured by Tokuyama Corporation) was sequentially added. A modified inorganic pigment sol B was obtained. Further, an ink jet recording material was prepared using the modified inorganic pigment sol B in the same manner as in Example 1.
The resulting modified inorganic pigment had a pore volume of 1.5 ml / g and an average secondary particle size of 162 nm.

Example 3
Instead of stirring for 20 minutes at a stirring speed of 15000 rpm with a high-speed disperser, Example 2 except that the pulverization dispersion treatment (pressure 50 MPa) was performed once with a microfluidizer (manufactured by Microfluidics, model number: M110 / EH). Similarly, a modified inorganic pigment sol C was prepared.
Further, an ink jet recording material was prepared using the modified inorganic pigment sol C in the same manner as in Example 1. The resulting modified inorganic pigment had a pore volume of 1.4 ml / g and an average secondary particle size of 147 nm.

Example 4
A modified inorganic pigment sol D was prepared in the same manner as in Example 3 except that lactic acid was used instead of acetic acid. Further, an ink jet recording material was prepared using the modified inorganic pigment sol D in the same manner as in Example 1.
The resulting modified inorganic pigment had a pore volume of 1.4 ml / g and an average secondary particle size of 142 nm.

Example 5
Example 4 and Example 4 except that instead of polyallylamine, a 15% aqueous solution of polydiallyldimethyldimethylammonium chloride (Unicens CP-102 manufactured by Senka Co., Ltd., average molecular weight ≈50000, cation equivalent = 5.9 meq / g) was used. Similarly, a modified inorganic pigment sol E was prepared. Further, an ink jet recording material was prepared using the modified inorganic pigment sol E in the same manner as in Example 1.
The resulting modified inorganic pigment had a pore volume of 1.5 ml / g and an average secondary particle size of 149 nm.

Example 6
Glycolic acid instead of acetic acid, 15% aqueous solution of methyldiallylamine hydrochloride polymer (PAS-M-1, manufactured by Nittobo Co., Ltd., average molecular weight≈20,000, cation equivalent = 6.2 meq / g) instead of polyallylamine A modified inorganic pigment sol F was prepared in the same manner as in Example 3 except that it was used. Further, an ink jet recording material was prepared using the modified inorganic pigment sol F in the same manner as in Example 1.
The resulting modified inorganic pigment had a pore volume of 1.4 ml / g and an average secondary particle size of 144 nm.

Example 7
An ink jet recording material was prepared in the same manner as in Example 4 except that the support A (paper base) was used instead of the support B (RC paper base) as the support.

Example 8
Example 4 is the same as Example 4 except that gas phase method silica (trade name: Leorociol QS-30, average primary particle size 7 nm, manufactured by Tokuyama Corporation) having a specific surface area of 300 m ² / g is used instead of Leorociol QS-102. Thus, a modified inorganic pigment sol G was prepared. Further, an ink jet recording material was prepared using the modified inorganic pigment sol G in the same manner as in Example 1.
The resulting modified inorganic pigment had a pore volume of 1.5 ml / g and an average secondary particle size of 138 nm.

Example 9
Commercially available gel method silica (trade name: Silojet P612, manufactured by Grace Devison) was dispersed in ion-exchanged water, pulverized and dispersed with a sand grinder, and then the above pulverization and dispersion treatment with a microfluidizer was repeated 10 times at a treatment pressure of 50 MPa. The mixture was pulverized and dispersed to obtain a 40% silica sol aqueous dispersion.
3.3 g of N-2- (aminoethyl) -3-aminopropyltrimethoxysilane was added to 138.6 g of ion-exchanged water stirred at 2000 rpm and sufficiently stirred. Next, after 16.7 g of 10% malic acid aqueous solution and 4.6 g of 10% sulfuric acid aqueous solution were added, PAA-15C: 12.4 g and the above 40% silica sol aqueous dispersion: 231.8 g were sequentially added. In the same manner as in Example 3, a modified inorganic pigment sol H was prepared. Further, an ink jet recording material was prepared using the modified inorganic pigment sol H in the same manner as in Example 1.
The resulting modified inorganic pigment had a pore volume of 1.1 ml / g and an average secondary particle size of 276 nm.

Comparative Example 1
A modified inorganic pigment sol J was prepared in the same manner as in Example 3 except that polyallylamine which was a cationic resin was not added. Further, an ink jet recording material was prepared using the modified inorganic pigment sol J in the same manner as in Example 1.
The resulting modified inorganic pigment had a pore volume of 1.4 ml / g and an average secondary particle size of 140 nm.

Comparative Example 2
Example 3 except that instead of polyallylamine, a 15% aqueous solution of methylvinylimidazolium vinylpyrrolidone chloride (30:70) copolymer liquid (BASF, Rubycut FC370, cation equivalent = 2.5 meq / g) was used. Similarly, a modified inorganic pigment sol K was prepared. Further, an ink jet recording material was prepared using the modified inorganic pigment sol K in the same manner as in Example 1.
The resulting modified inorganic pigment had a pore volume of 1.3 ml / g and an average secondary particle size of 148 nm.

Comparative Example 3
A modified inorganic pigment sol L was prepared in the same manner as in Example 3 except that N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, which is an aminosilane coupling agent, was not added. Further, an ink jet recording material was prepared using the modified inorganic pigment sol L in the same manner as in Example 1.
The resulting modified inorganic pigment had a pore volume of 1.2 ml / g and an average secondary particle size of 151 nm.

Comparative Example 4
A modified inorganic pigment sol M was prepared in the same manner as in Example 3 except that the same amount of acetic acid was added in place of hydrochloric acid, which is an inorganic acid. Further, an ink jet recording material was prepared using the modified inorganic pigment sol M in the same manner as in Example 1.
The resulting modified inorganic pigment had a pore volume of 1.3 ml / g and an average secondary particle size of 144 nm.

Comparative Example 5
A modified inorganic pigment sol N was prepared in the same manner as in Example 3 except that the same amount of hydrochloric acid was additionally added instead of acetic acid, which is an organic acid. Further, an ink jet recording material was prepared using the modified inorganic pigment sol N in the same manner as in Example 1.
The resulting modified inorganic pigment had a pore volume of 1.2 ml / g and an average secondary particle size of 142 nm.

"Evaluation methods"
The ink jet recording materials obtained in Examples and Comparative Examples were evaluated by the following methods. The production conditions of each recording material were shown in Table 1, and the evaluation results were shown in Table 2.

(Paint gloss)
The coated surface of the obtained ink jet recording material was measured based on ISO 8254-1 using a gloss meter (GM-26 PRO / AUTO) of Murakami Color Research Laboratory.

(Print density measurement)
Super photo paper recommended setting mode of Canon printer: PIXUS-iP8600 (machine installed with dye ink) in an environment of 23 ° C. and 50% humidity (ISO environment) on each sample cut to L size (89 mm × 127 mm) 100% black solid was printed with the setting (no matching), and was dried in an ISO environment for 24 hours. This printed part was measured using a black filter of a Macbeth reflection densitometer (manufactured by Macbeth, RD-914). The numbers shown in the table are average values of five measurements.

(Continuous printing evaluation test under high temperature and high humidity)
Samples were cut to L size (89 mm x 127 mm), and each two sheets were conditioned for 24 hours in an environment of 30 ° C and 80% humidity, then Canon Inc. inkjet printer: PIXUS-iP4200 Super Photo Paper recommended setting, JIS -X9201 "High-definition color digital standard image CMYK / SCID" Image identification number: N1 was printed in succession. The sample after printing was immediately sandwiched between two L-sized glass plates having a thickness of 5 mm and left in the same environment. After 24 hours, the print sample output on the first sheet (the one on which the second sheet was laminated) was taken out and dried in an environment of 23 ° C. and 50% humidity for 2 hours. As a normal image for comparison, a print sample was prepared after humidity control was performed in an environment of 23 ° C. and 50% humidity, followed by printing and drying without stacking. Similarly, in place of the N1 image, a pattern image “a pattern in which 100% red, green, and blue of 1 cm ² corners are connected horizontally and arranged in three rows vertically with an interval of 1 mm and 0.5 mm” is also used. A normal print sample was prepared. The color tone was mainly confirmed from the N1 image, and the blur was mainly confirmed from the pattern image, and was evaluated in five levels based on the following indices.

《Color tone evaluation index》
5 points: Even an image laminated by continuous printing under severe conditions of high temperature and high humidity has a clear color tone equivalent to that of a normal image.
4 points: Although the color tone is slightly different from that of a clear normal image, the layered image has a clear color tone with no unnaturalness when viewed alone.
3 points: The normal image is clear, but the color of the layered image is sunk, and there is an unnatural impression alone.
2 points: The sharpness of the normal image is slightly inferior, and the layered image has a more unnatural impression because the color further sinks.
1 point: The color tone of the normal image is clearly unnatural.

《Budget evaluation index》
5 points: There is no blur even in images laminated by continuous printing under severe conditions of high temperature and high humidity.
4 points: Although there is a slight blur at the printing boundary portion (solid portion to white paper, or solid portion to solid portion) of the laminated image, it is at a level with no problem.
3 points: There is blurring that can be discriminated at the printing boundary of the laminated image.
2 points: The laminated image is clearly blurred, but the normal image is not blurred.
1 point: Normal image is also blurred.

(Light resistance)
Using an ink-jet printer PM-G820 manufactured by Seiko-Epson Corporation, an ISO-400 image (“high-definition color digital standard image data ISO / JIS-SCID”, image name: portrait, 2) 70% solid magenta was output for each sample with the same setting (no color correction). The obtained images were left for 24 hours in an ISO environment without being laminated, and one piece was used with a xenon weather meter (Super Xenon Weather Meter SX75 manufactured by Suga Test Instruments Co., Ltd.), 23 ° C., humidity 50%, wavelength The exposure treatment was performed for 72 hours at a setting of 300 to 400 nm and 80 W / m2. After the processing, together with the unprocessed images stored in the dark place of the ISO environment, the remaining rate and the image quality were evaluated in five levels based on the following indices.
[Survival rate]
The 70% magenta solid print density of the treated and untreated products was measured, and the remaining rate was calculated.
Residual rate (%) = printed density of treated product / printed density of untreated product × 100
[Light fast image quality]
The hue change before and after the portrait image processing was evaluated according to the following criteria.
5 points: There is little fading in the entire processed image, and the color balance is good.
4 points: Although there is no particular sense of incongruity in the processed image alone, a trace of fading can be seen in comparison with the unprocessed image.
3 points: A trace of fading can be seen in the processed image alone.
2 points: The entire processed image is faded.
1 point: Since the color fading tendency of the processed image differs depending on the ink, the color balance is poor.

  As is clear from Examples 1 to 9 in Table 1 and Table 2, the ink jet recording material comprising the modified inorganic pigment of the present invention has a high printing density and is laminated by continuous printing because of good ink fixing ability. Even when kept in the same state, a clear image that is the same as the normal environment can be obtained, and the light resistance of the image was also good. Inkjet printers are now widely used as easy-to-use output devices, including those in ordinary homes, so they produce multiple photo-like outputs in a high-temperature, high-humidity environment and are stored in a stacked state, such as sunlight and fluorescent lights. It is highly assumed that they will be posted and stored in an environment where they are exposed to the rays of light. Even under such harsh conditions, the ink jet recording material using the modified inorganic pigment of the present invention is a main pigment, an aminosilane coupling agent used for modification, a cationic resin, an organic acid, a kind of inorganic acid, It was confirmed that good images could be retained regardless of the support.

  On the other hand, as shown in Comparative Example 1, when the inorganic pigment was modified only by an aminosilane coupling agent, which is a general technique, the ink fixing ability of the obtained ink jet recording material was insufficient. Further, even if a cation resin having a cation equivalent outside the specification of the present invention was used, the required ink fixing ability could not be obtained. On the other hand, when the aminosilane coupling agent was not used and only the cationic resin was used for modification, the resulting ink jet recording material was extremely inferior in image light resistance and was unsuitable (Comparative Example 3). Even when both an aminosilane coupling agent and a cationic resin are used as the cation component, if either the inorganic acid or the organic acid, which is an essential component of the present invention, is lacking, an inkjet recording material having sufficient quality could not be obtained. (Comparative Examples 4 and 5).

Claims (11)

A modified inorganic pigment characterized in that the surface of the inorganic pigment is modified with a treatment liquid containing a hydrophilic resin having a cation equivalent of 4.0 meq / g or more, an amino group-containing silane coupling agent, an organic acid and an inorganic acid. . Treatment liquid containing at least one hydrophilic resin selected from polymers containing polyvinylamine, polyallylamine, polydiallyldimethylammonium chloride, and 5-membered ring amidine structure, amino group-containing silane coupling agent, organic acid and inorganic acid A modified inorganic pigment characterized in that the surface of the inorganic pigment is modified. The modified inorganic pigment according to claim 1 or 2, wherein the hydrophilic resin has a weight average molecular weight of 5,000 to 100,000. Amino group-containing silane coupling agent is 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, N-2- (aminoethyl) It is at least one selected from -3-aminopropyltriethoxysilane and N-2- (n-butyl) -3-aminopropyltrimethoxysilane, or a hydrolyzate and polymer thereof. 3. The modified inorganic pigment according to any one of 3. The modified inorganic pigment according to claim 1, wherein the organic acid and the inorganic acid are monovalent acids. The modified inorganic pigment according to claim 1, wherein the organic acid is a carboxylic acid or a hydroxycarboxylic acid. The modified inorganic pigment according to any one of claims 1 to 6, wherein the inorganic pigment is gas phase method silica having primary particles of 40 nm or less. An ink jet recording material comprising the modified inorganic pigment according to claim 1. After dissolving an amino group-containing silane coupling agent in a polar solvent, an organic acid and an inorganic acid are added, and at least selected from a polymer containing polyvinylamine, polyallylamine, polydiallyldimethylammonium chloride, and a 5-membered ring amidine structure. A method for producing a modified inorganic pigment sol, comprising dispersing an inorganic pigment in a treatment liquid to which a kind of hydrophilic resin is added. The method for producing a modified inorganic pigment sol according to claim 9, wherein a mechanical share is given after adding the inorganic pigment to the treatment liquid. In the manufacturing method of the inkjet recording body which forms the ink receiving layer by apply | coating the coating liquid for ink receiving layers to a support body, and drying, the modification obtained by the method of Claim 9 or 10 in the coating liquid for ink receiving layers A method for producing an ink jet recording material, comprising an inorganic pigment sol.