JPH1178209A - Image forming material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a high dye fixing property even under a high temperature high humidity environment while excellent transparency and glossiness are obtained by a method wherein a dye fixing compound in which a specific organic acid is adsorbed onto a hydrotalcite group compound expressed by the formula, is contained in an accepting layer. SOLUTION: There is used a dye fixing compound in which an organic acid 4 is adsorbed onto a hydrotalcite group compound 1 expressed by the formula I or formula II. The hydrotalcite group compound 1 is so-called a laminar composite hydroxide, which is a compound presenting a laminar structure in which many octahedral layers of metal hydroxide are laminated. As the organic acid 4 to be adsorbed onto the hydrotalcite group compound 1, any one of phthalic acid, isophthalic acid, terephtahlic acid and maleic acid is used. Further, there may be used the dye fixing compound in which the organic acid 4 is adsorbed onto a burnt material of the hydrotalcite group compound 1 expressed by the formula I or the formula II and hydrated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming material having a receptor layer to which a dye is fixed, and more particularly to an image forming material suitable for use in an ink jet recording system.

[0002]

2. Description of the Related Art In recent years, a display image displayed on a personal computer or the like has been recorded on photographic paper in the same manner as a silver halide photograph. As a recording method used for such recording, an image forming method called an ink jet recording method is known.

In the ink jet recording method, a solution-like ink liquid is ejected from a nozzle using an electric field, heat, pressure or the like as a driving source, and is transferred to a receiving layer of photographic paper.

Here, the ink liquid is composed of a dye, water, a polyhydric alcohol, and the like. As the dye, a water-soluble direct dye or an acidic dye is mainly used.

[0005] Further, the photographic paper is constituted by forming a receptor layer for receiving a dye on a support. The receiving layer is composed of a water-soluble polymer having an excellent affinity for the dye, an organic filler or an inorganic filler, and other auxiliary substances.The mixing ratio of these components is controlled from the viewpoint of controlling dye penetration and image bleeding. Has been adjusted.

In recent years, the quality of images obtained by such an ink jet recording system has been remarkably improved. The improvement in dot density and the improvement in glossiness of the receiving layer have led to higher definition. The quality of salt photography can be obtained.

By the way, direct dyes and acid dyes used in the ink jet recording system transfer to the receiving layer as indicated by the dyeing theory of the dye, and then, such as van der Waals force and hydrogen bonding with the components of the receiving layer. It is retained in the receiving layer by interaction.

For this reason, the image formed on the receiving layer is
Elution or migration of the dye is induced when it comes into contact with a solvent or resin that has a higher affinity for the dye, or when heat energy sufficient to cancel these interactions is induced, causing image blurring, etc. Disadvantages occur. In other words, there is a situation where perfect fixability is not exhibited as in silver halide photography. This means stationery using direct dyes or acid dyes,
The same applies to general printing materials used for printing and the like.

On the other hand, for example, Japanese Patent Publication No. 62-798
No. 4,694,302, Japanese Patent Laid-Open No. 1-22
No. 5,585, Japanese Patent Publication No. 63-11158, etc., have proposed a method of retaining a dye in a receptor layer by forming a chemical bond.

In these cases, a reactive dye and a reactive group form a covalent bond with an active group in the receptor layer, or a dye anion and an organic polymer cation in the receptor layer form an ionic bond, or The dye is held in the receiving layer by forming an ionic bond with the inorganic low molecular cation in the receiving layer.

However, the dye or the composition of the receptor layer that forms a chemical bond has a very high reactivity, and thus has poor storage stability. In addition, the reaction between the dye and the receiving layer composition is not completed in a short time, and it takes a long time to form a stable image, and there is a trouble that an auxiliary means such as heating is required for the reaction. In addition, there are drawbacks in that the preparation of the dye is difficult, the usable hue is limited, and it is difficult to secure the transparency and gloss of the image. Further, an image formed by using a chemical bond often has insufficient solvent resistance and light resistance even though it exhibits water resistance.

As described above, various fixing systems have been proposed for the ink jet recording system, but all have problems. For this reason, practical application in fields where image durability is strictly required, such as ID photos and outdoor exhibition printing, is greatly hindered, and further improvements in fixability, image saturation, and resolution are required.

In order to meet these demands, a dye image fixing system utilizing intercalation based on ion exchange as disclosed in JP-A-7-68925 has been proposed. In this fixing system, ions are previously adsorbed to the receiving layer composition, and when the dye is transferred to the receiving layer, the dye is retained by adsorbing the dye instead of the ions to the receiving layer composition. It is. According to this method, an image with high chroma and high resolution can be formed, and the formed image has excellent water resistance.

[0014]

However, the image formed by the intercalation tends to cause image bleeding in a severe environment such as high temperature and high humidity, and this bleeding is particularly remarkable in a high density portion having a high dyeing density.

[0015] For example, in a tropical climate, a subtropical climate, or even in a temperate zone, in the case of direct contact with air under rainy season conditions, an image bleeds during long-term storage even at room temperature, and image quality is significantly impaired. Will be.

Moreover, the receptor layer used in this intercalation cannot be said to have sufficiently high transparency and glossiness, and further improvement is required to form a high-quality image.

Therefore, the present invention has been proposed in view of such a conventional situation, and has a receiving layer excellent in transparency and gloss, and has a high dyeability even in a severe environment such as high temperature and high humidity. It is an object of the present invention to provide an image forming material capable of obtaining a fixing property.

[0018]

In order to achieve the above-mentioned object, the image-forming material of the present invention has a dye fixing property in which an organic acid is adsorbed on a hydrotalcite compound represented by the formula (5) or (6). It has a receptor layer containing a compound, and the organic acid is any one of phthalic acid, isophthalic acid, terephthalic acid, and maleic acid.

The calcined product of the hydrotalcite compound represented by the chemical formula (5) or (6) has a receptor layer containing a dye-fixing compound hydrated by absorbing an organic acid.
The organic acid is alkenyl acid, phthalic acid or a derivative thereof.

[0020]

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[0021]

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The hydrotalcite compound represented by Chemical Formula 5 or 6 is a crystalline compound having a layered structure. This crystalline compound has a single crystalline phase within the range of x represented by the above general formula, and is a submicron microcrystalline particle and its refractive index is close to that of a conventional polymer material or resin. Thereby, when used as a material for the receiving layer, a receiving layer having high transparency is formed.

Further, a predetermined organic acid is adsorbed on the crystal compound, and ions of the organic acid are held between the layers of the crystal compound, thereby increasing the distance between the layers of the crystal compound. For this reason, when a dye is provided to the receiving layer, the dye anion is rapidly transferred between the crystalline compound layers, and ion exchange between the inorganic anion and the dye anion held between the layers by ionic bonding, and in some cases, the organic acid ion Ion exchange of the dye anion or electronic interaction between the dye and the organic acid occurs, and the dye is strongly adsorbed to the crystalline compound layer. As a result, bleeding of an image is prevented in a high-density printing area even under a severe environment such as high temperature and high humidity, and an image having excellent fixability is formed.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described.

The image forming material of the present invention has a receptor layer containing a dye-fixing compound, and an image is formed by transferring and fixing the dye to the receptor layer.

As the dye-fixing compound, a compound obtained by adsorbing an organic acid to a hydrotalcite compound represented by the following formula (7) or (8) is used.

[0027]

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[0028]

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The hydrotalcite compounds are so-called layered double hydroxides and are compounds having a layered structure in which a large number of octahedral layers of metal hydroxide are laminated.

Here, the organic acid adsorbed on the hydrotalcite compound is any of phthalic acid, isophthalic acid, terephthalic acid and maleic acid.

As the dye-fixing compound, a compound obtained by adsorbing an organic acid and hydrating a calcined product of a hydrotalcite compound represented by the following formula (7) or (8) is also used.

This fired body is obtained by firing a hydrotalcite compound at a temperature of, for example, 500 to 800 ° C. When the hydrotalcite compound is calcined at such a temperature, it is thermally decomposed into a rock salt type oxide solid solution. When an organic acid is adsorbed on the mixture and injected into water, coexisting anions and water molecules are taken in and hydrated to form a layered double hydroxide having a layered structure again.

The organic acid adsorbed on the calcined product of the hydrotalcite compound is alkenyl acid, phthalic acid or a derivative thereof.

In the image forming material of the present invention, such a dye-fixing compound is contained in the receptor layer. In the receiving layer containing such a dye-fixing compound, a dye image is fixed by the following mechanism.

First, FIG. 1 schematically shows a layered structure of a hydrotalcite compound. As described above, the hydrotalcite compound 1 is a crystalline compound having a layered structure in which a large number of octahedral layers 2 of a metal hydroxide are stacked. In this hydrotalcite compound, an inorganic anion 3 such as a carbonate ion is held by an ionic bond between the layers 2 or at an end of an octahedral layer constituting the layer 2 when the organic acid is not adsorbed. . The interlayer distance in this state to d _1.

When this hydrotalcite compound 1 is suspended in water and an organic acid is added, ion exchange occurs. As shown in FIG. 2, the organic acid ion 4 replaces the inorganic anion 3 which was present beforehand. It is adsorbed and held between the layers 2. Interlayer distance d ₂ at this time is larger than the interlayer distance d ₁ in a state without the addition of organic acids.

In order to form an image on the receiving layer made of the hydrotalcite compound (dye-fixing compound) 1 holding the organic acid ions 4, ink droplets are dropped on a region corresponding to the image information. I do. As the ink droplets, those obtained by dissolving a direct dye or an acidic dye in a high dielectric constant solvent such as water or alcohol are used.

When an ink droplet is applied to the receiving layer, the hydrotalcite compound 1 holding the organic acid ions 4 has a large interlayer distance, so that the direct dye or acidic dye in the ink droplet is mixed with the solvent. Swiftly between layers 2 and so on.

Then, as shown in FIG. 3, ion exchange between the inorganic anion 3 and the dye anion 5 held between the layers 2, and in some cases, ion exchange between the organic acid ion 4 and the dye anion 5, or An electronic interaction with the organic acid (estimated as a π-π interaction) occurs, and the dye anion 5 is strongly adsorbed between the layers of the hydrotalcite compound 1. As a result, an image having excellent fixability is formed on the receiving layer.

Furthermore, in this case, excellent swelling properties can be obtained even with a non-aqueous solvent such as alcohol due to the hydrophobic nature of the organic acid ion. Migration and fixing are performed smoothly.

The dye fixing mechanism of the dye-fixing compound in which the organic acid is adsorbed on the hydrotalcite compound has been described above. The dye-fixing compound in which the organic acid is adsorbed on the calcined product of the hydrotalcite compound has been described. In this case, the dye transfer and fixing are performed by the same mechanism.

With this image forming material, excellent fixing properties can be obtained by the above fixing mechanism. However, in order to form an image having excellent transparency and glossiness as well as fixing properties, the composition of the hydrotalcite compound is required. Alternatively, it is necessary that the composition of the fired body before firing is a composition represented by Chemical Formula 7 or Chemical Formula 8. A hydrotalcite compound having such a composition has a single crystal phase within the range of x represented by the above general formula, and is a submicron microcrystalline particle and its refractive index is frequently used. When the material is used as a material for the receiving layer, a receiving layer having high transparency is formed because of being close to the polymer materials or resins. Therefore, high-quality image recording comparable to silver halide photography can be performed.

In order to obtain high fixability, it is important that the anion retained between the layers of the hydrotalcite compound or the hydrate of the calcined product thereof is a predetermined organic acid ion.

When the anion interposed between the layers of the hydrotalcite compound or the hydrate of the calcined product is only an inorganic anion, the fixability of the dye is insufficient, and the hue of the adsorbed dye changes with time. Will change.
However, in this case, if a large amount of the dye-fixing compound is added to the receiving layer, the fixing property is increased, but then the transparency, glossiness and film flexibility of the receiving layer are impaired.

Even when an organic acid is adsorbed, such as an organic carboxylic acid having a long carbon chain other than the one specified in the present invention, or a sulfonic acid, a sulfuric acid ester, a phosphoric acid ester or the like, Even if a surface to be adsorbed having excessively strong lipophilicity is formed to deprive the fixing seat (exchangeable anion) of the hydrophilic dye, and even if the dye is adsorbed, the electronic interaction with the dye molecule is weak on this surface. Bleeding occurs at high printing density portions. Further, when an organic acid other than the specified one is adsorbed, the dispersibility of the dye-fixing compound in the polymer binder or the hydrophilic solvent becomes low, and the gloss and transparency of the receiving layer are impaired.

The amount of the organic acid adsorbed on the hydrotalcite compound or the calcined product thereof is 0.2 to 1.1 in terms of the equivalent ratio of the organic acid to the anion exchange capacity of the hydrotalcite compound. Is desirable. If the amount of the organic acid adsorbed is smaller than this amount, the effect of improving the transfer and fixability of the dye by the organic acid cannot be sufficiently obtained. If the amount of organic acid adsorbed is larger than this amount, the number of dye fixing seats becomes extremely small, and the water absorbing capacity of the receiving layer increases to an impractical level, so that good image recording can be performed. Disappears.

The receiving layer containing such a dye-fixing compound is mainly composed of, for example, the above-mentioned dye-fixing compound and a polymer binder. To form this receptor layer, various additives are dispersed in a high-dielectric solvent together with these main components to prepare a paint, and the paint is applied on a support and dried.

As the polymer binder, a thermoplastic resin is used. However, the adsorptivity by ion exchange or the like to a substituent which inhibits fixing of a dye, for example, a dye fixing compound, is relatively larger than that of the dye. Those containing a substituent are not preferred.

Various additives may be added to the receiving layer as long as the fixing property is not impaired. Examples of the additives include a plasticizer that lowers the glass transition point Tg of the polymer binder, an auxiliary additive for controlling water absorption and chargeability, an ultraviolet absorber for improving light fastness, and a receptor layer. A fluorescent whitening agent or the like for improving glossiness and transparency is used.

In the receiving layer composed of the above-mentioned materials, the amount of the dye-fixing compound to be added is 10 to 90% by weight of the solid content (dye-fixing compound, polymer binder, solid additive) constituting the receiving layer. And more preferably 20 to 90% by weight. If the amount of the dye-fixing compound is below this range, the fixability will be insufficient. On the other hand, if the amount of the dye-fixing compound exceeds this range, a highly flexible receiving layer cannot be obtained.

The support for forming the receiving layer is
It is appropriately selected according to the use of the image forming material. For example, when an image forming material is used as a printing sheet, a film-like support is used. As a material for this support,
Paper, synthetic paper, plastic film, metal plate, metal foil,
A plastic film on which aluminum is deposited is exemplified. In the case of an image forming material used for an application such as an OHP (overhead projector), a film made of an optically transparent material is used.

The dyes to be fixed on such an image forming material include, for example, the following direct dyes and acid dyes.

Direct dyes and acid dyes include monoazo, disazo, anthraquinone, triphenylmethane and the like as chromophores, and have 1 to 3 anionic water-soluble groups such as sulfonic acid groups or carboxyl groups in the molecule. It has. However, the direct dye generally has a larger molecular weight than the acid dye.

To be more specific, the direct dyes include C.I. I Direct Yellow 1, 8,
11, 12, 24, 26, 27, 28, 33, 39, 4
4, 50, 58, 85, 86, 87, 88, 89, 9
8, 100, 110, etc., and C.I. I Direct Red 1, 2, 4, 9, 11, 13,
17, 20, 23, 24, 28, 31, 33, 37, 3
9, 44, 46, 62, 63, 75, 79, 80, 8
1, 83, 84, 89, 95, 99, 113, 197,
201, 218, 220, 224, 225, 226, 2
27, 228, 229, 230, 231 and the like. Cyan dyes include C.I. I Direct Blue 1, 2, 6, 8, 15, 22, 25, 41, 71, 7
6, 77, 78, 80, 86, 90, 98, 106, 1
08, 120, 158, 160, 163, 165, 16
8, 192, 193, 194, 195, 196, 19
9, 200, 201, 202, 203, 207, 22
5, 226, 236, 237, 246, 248, 249
And black dyes such as C.I. I. Direct Black 17, 19, 22, 32, 38, 51,
56, 62, 71, 74, 75, 77, 94, 105,
106, 107, 108, 112, 113, 117, 1
18, 132, 133, 146 and the like.

Acid dyes include C.I. I Acid Yellow 1, 3, 7, 11, 17,
19, 23, 25, 29, 36, 38, 40, 42, 4
4, 49, 59, 61, 70, 72, 75, 76, 7
8, 79, 98, 99, 110, 111, 112, 11
4, 116, 118, 119, 127, 128, 13
1, 135, 141, 142, 161, 162, 16
3, 164, 165 and the like, and C.I. I Acid Red 1, 6, 8, 9, 13, 14, 1
8, 26, 27, 32, 35, 37, 42, 51, 5,
2, 57, 75, 77, 80, 82, 83, 85, 8
7, 88, 89, 92, 94, 97, 106, 111,
114, 115, 117, 118, 119, 129, 1
30, 131, 133, 134, 138, 143, 14
5, 154, 155, 158, 168, 180, 18
3, 184, 186, 194, 198, 199, 20
9, 211, 215, 216, 217, 219, 24
9, 252, 254, 256, 257, 262, 26
5, 266, 274, 276, 282, 283, 30
3, 317, 318, 320, 321, 322 and the like. Cyan dyes include C.I. I Acid Blue 1, 7, 9, 15, 22, 23, 25, 27, 29,
40, 41, 43, 45, 54, 59, 60, 62, 7
2, 74, 78, 80, 82, 83, 90, 92, 9
3, 100, 102, 103, 104, 112, 11
3, 117, 120, 126, 127, 129, 13
0, 131, 138, 140, 142, 143, 15
1, 154, 158, 161, 166, 167, 16
8, 170, 171, 175, 182, 183, 18
4,187,192,199,203,204,20
5, 229, 234, 236 and the like. I Acid Black 1, 2, 7, 2
4, 26, 29, 31, 44, 48, 50, 51, 5
2, 58, 60, 62, 63, 64, 67, 72, 7
6, 77, 94, 107, 108, 109, 110, 1
12, 115, 118, 119, 121, 122, 13
1, 132, 139, 140, 155, 156, 15
7, 158, 159, 191 (black).

These direct dyes and acid dyes are dissolved in a solvent to form an ink liquid. However, as the dye, even if the counter cation of the dye is replaced with an organic ion for the purpose of controlling compatibility with solvents used as auxiliary additives of the ink and bleeding in the receiving layer. Good.

Such an ink liquid is transferred to the receiving layer by, for example, an ink jet recording method. In this ink jet recording method, a solution ink is discharged from a nozzle and transferred to a receiving layer of photographic paper. The drive source for ejecting ink from the nozzle may use a piezo element or a thermosensitive element whose volume changes by applying a voltage, and in addition, any of those commonly used in an ink jet recording method may be used. Can be used.
The means for transferring the ink liquid to the receiving layer may be a stationery such as a stamp or a writing instrument.

[0058]

EXAMPLES Hereinafter, specific examples of the present invention will be described based on experimental results.

Examination of Dye Adsorption of Dye Fixing Compound
(1) In the above chemical formula 7, M ^II is a divalent metal ion of Mg, M ^III is a trivalent metal ion of Al, A is a nitrate ion,
Synthetic hydrotalcite (Mg ₆ Al ₂ (OH) ₁₆ (NO ₃ ) ₂ .4H ₂ O) with x = 0.25 and m = 0.5 was prepared.

Then, 20 g of this hydrotalcite
Was dispersed in 1 liter of water, and an equal amount (equivalent number of organic acids per Al atom: 1.0) of Table 1 was added to the dispersion.
An aqueous solution in which various organic acids or alkali salts were dissolved was added dropwise with stirring. The amount of the organic acid added is equivalent to the anion exchange capacity of the hydrotalcite used. As a result, granular coagulation / sedimentation immediately occurred. The dispersion was allowed to stand for 24 hours, and then the precipitate was separated by filtration and washed with ethanol. Subsequently, the washed precipitate is brought to a temperature of 70 ° C.
, A pure white powder (dye-fixing compound) was obtained.

The average particle size of the obtained dye-fixing compound, specific surface area by BET method, XRD (X-Ray-D
Table 1 shows d _{(003) based} on the effect.
From the value of XRDd ₍₀₀₃₎ , it was determined that organic acid ions were adsorbed between the layers of the hydrotalcite compound.

[0062]

[Table 1]

Then, the adsorptivity of the dye-fixing compound to the dye was evaluated as follows.

First, 1.0 g of these dye-fixing compounds
Was dispersed in 100 g of pure water using an ultrasonic disperser to prepare a white suspension. Then, chlorazole black LF (manufactured by Tokyo Chemical Industry Co., Ltd.) as a black dye was added to the suspension of the dye-fixing compound, and the mixture was allowed to stand overnight at room temperature to reach adsorption equilibrium.

[0065]

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Next, the amount of the dye remaining in the aqueous solution (the amount of the dye that did not adsorb to the dye-fixing compound) was determined spectrophotometrically, and this amount was determined from the amount of the dye added to the suspension. The amount of the dye adsorbed on the dye-fixing compound was calculated by subtraction. The amount of the dye added to the suspension was 0.0
It was changed within a range of 10 mol / l or less. The relationship between the amount of dye in the aqueous solution and the amount of dye adsorbed on the dye-fixing compound (adsorption isotherm) is shown in FIGS. 4 and 5 for each dye-fixing compound. FIG. 4 also shows the adsorption isotherm of the dye-fixing compound to which the inorganic acid (HNO ₃ ) has been adsorbed.

Referring first to FIG. 5, the dye-fixing compound adsorbing an aromatic acid such as phthalic acid, isophthalic acid and terephthalic acid or maleic acid has a saturated adsorption amount of the dye of 2%.
It exceeds 0 mmol / 100 g, indicating that the absolute adsorption amount of the dye is larger than that of the dye-fixing compound to which another organic acid is adsorbed.

For example, a dye-fixing compound to which dodecylbenzenesulfonic acid is adsorbed even with an aromatic acid has a small saturated adsorption amount of the dye of 10 mmol / 100 g or less.
This is because in the case of dodecylbenzene sulfonic acid, an extremely hydrophobic surface is formed, so that the swelling property of the dye-fixing compound in water is impaired, and the contact between the dye molecule and the dye fixing seat is cut off. It is estimated to be.

In the dye-fixing compound having acrylic acid adsorbed thereon, the amount of dye adsorbed quantitatively increases in a range where the amount of dye added is extremely small. The amount is almost unchanged, and the saturated adsorption amount of the dye is 14 mmol / 100 g or less. Here, in the case of the dye-fixing compound in which acrylic acid is adsorbed, it is known that the interlayer distance is relatively large, and it is considered that the substitution amount of the dye is considered to be large, but as shown in this experiment, It is considered that the reason why the saturated adsorption amount becomes small is that ion exchangeability with the dye is inferior.

Further, the dye-fixing compound to which an aliphatic dibasic acid such as adipic acid or sebacic acid has been adsorbed exhibits a behavior in which the dye is desorbed when the dye is further added after the amount of adsorption reaches saturation. . Therefore, this dye-fixing compound is considered to be unsuitable when a large excess of dye is used.

From the above, it was found that phthalic acid, isophthalic acid, terephthalic acid and maleic acid were suitable as organic acids to be adsorbed on hydrotalcite compounds.

Investigation of printability (1) 30 g of the various dye-fixing compounds shown in Table 1 were put into 1 kg of an ethanol solution containing 1% by weight of polyvinyl butyral (trade name BL-1 manufactured by Sekisui Chemical Co., Ltd.), and the mixture was subjected to sand milling. The suspension for the receiving layer was prepared by dispersing for a time.

This suspension for receptor layer is applied and impregnated on one side of a transparent polyester film having a thickness of 110 μm using a doctor blade, and then dried with hot air at 110 ° C. for 1 minute to form a solid film (receptor layer). Was formed.

Then, the film on which the receiving layer is formed is pressure-bonded by a pair of elastic rollers having a surface temperature of 120 ° C. while sending the film at a speed of 10 cm / sec. A photographic sheet was prepared by cooling.

The printing sheet created in this way is
Printer (MJ-800, manufactured by Seiko Epson Corporation)
The ink jet recording was carried out in the black and white print mode by mounting on the paper feed tray of C). The composition of the ink liquid is shown below.

Composition of ink liquid: Dye: chlorazole black LF 2 parts by weight Triethylene glycol diacetate 5 parts by weight Propylene glycol 2 parts by weight Water 40 parts by weight The transparency, ink absorbency,
The light resistance, temperature and humidity resistance were evaluated. Table 2 shows the results. In addition, these characteristics were evaluated as follows.

Transparency: A printing sheet on which no black-and-white image was formed was irradiated with all light rays, and the transmittance thereof was measured. The case where the transmittance was 80% or more was represented by “○”, and the case where the transmittance was less than 80% was represented by “×”.

Ink Absorption: The black and white image formed on the printing sheet was visually observed, and the state of overflow of the ink liquid was evaluated. The case where no overflow was observed in the image was represented by “○”, and the case where overflow was observed was represented by “×”.

Light fastness: A black-and-white image formed on a printing sheet was exposed with a Xe lamp (Blue Sole Class 4). Then, ΔE (color difference) before and after exposure was determined.
The case of ΔE <5 was represented by “○”, and the case of ΔE ≧ 5 was represented by “x”.

Temperature and humidity resistance: The printing sheet on which a black-and-white image was formed was left for 24 hours in an environment of a temperature of 60 ° C. and a relative humidity of 90%. Then, ΔE (color difference) before and after standing was determined.
“○” when ΔE <10, “×” when ΔE ≧ 10
It was expressed by.

[0081]

[Table 2]

As shown in Table 2, the printing sheets using the dye-fixing compound to which phthalic acid, isophthalic acid, terephthalic acid or maleic acid was adsorbed were all transparent,
It has excellent temperature and humidity resistance, and also has good ink absorption and light resistance.

Thus, the dye-fixing compound obtained by adsorbing phthalic acid, isophthalic acid, terephthalic acid, and maleic acid to the hydrotalcite compound is superior as a material for the receiving layer of a printing sheet, as compared with other dye-fixing compounds. I understood that.

However, the amount of the organic acid adsorbed on the hydrotalcite compound is preferably such that the equivalent ratio of the hydrotalcite compound to the anion exchange capacity is 0.2 to 1.1. . Table 3 shows typical examples.
The characteristics of a printing sheet using a dye-fixing compound in which phthalic acid is adsorbed so that the equivalent ratio to the anion exchange capacity of the hydrotalcite compound is 0.05 or 2.00 are shown. When the ratio is as small as 0.05, transparency, light resistance, and temperature / humidity resistance are impaired. When the equivalence ratio is as large as 2.00, the ink absorbency is insufficient.

[0085]

[Table 3]

Examination of Dye Adsorption of Dye Fixing Compound
(2) was prepared synthesized oxide obtained hydrotalcite calcined solid solution Mg _0.7 Al _0.3 O _1.15 (manufactured by Kyowa Chemical Industry Co., Ltd. trade name Kyoward 2200). Then, 20 g of this oxide solid solution is dispersed in 1 liter of water,
Then, a solution in which malic acid was dissolved in 200 cc of water was added dropwise to the dispersion with stirring. The amount of malic acid added is 0.4 equivalent or 1.0 equivalent in equivalent ratio to the exchange capacity. As a result, immediately
Settling occurred. After allowing this dispersion to stand for 24 hours, the precipitate was filtered off and washed with water. Subsequently, the washed precipitate was dried at a temperature of 70 ° C. to obtain a pure white powder (dye-fixing compound).

X-ray diffraction analysis of the thus obtained dye-fixing compound showed that the dye-fixing compound treated with malic acid at an equivalent ratio of 0.4 had XRDd ₍₀₀₃₎ of 7.96 Å. And a dye-fixing compound treated with malic acid at an equivalent ratio of 1.0 and having an XRDd ₍₀₀₃₎ of 12.9.
1 angstrom. From this value, it was determined that adsorption of organic acid ions occurred between layers of the oxide solid solution.

Further, in the same manner as in the case of malic acid, any one of salicylic acid, acrylic acid, phthalic acid, p-toluenesulfonic acid (PTSA), adipic acid and succinic acid is adsorbed on the oxide solid solution to form various dye-fixing compounds. I got The amount of the organic acid adsorbed was 0.1 in an equivalent ratio to the exchange capacity.
It is 4 equivalents or 1.0 equivalent.

1.0 g of the dye-fixing compound thus obtained was dispersed in 100 g of pure water to prepare a white suspension. Acid Red 52 or chlorazole black LF was added as a dye in various amounts to the suspension of the dye-fixing compound, and the adsorption isotherm for the dye was examined in the same manner as described above. The results are shown in FIGS. FIG. 6 is an adsorption isotherm for Acid Red 52, and FIG. 7 is an adsorption isotherm for chlorazole black LF of a dye-fixing compound treated with an organic acid having an equivalent ratio of 0.4 among the dye-fixing compounds. is there.
6 and 7 also show the adsorption isotherm of the oxide solid solution not adsorbing the organic acid for comparison.

First, it can be seen from FIG. 6 that the dye-fixing compound treated with acrylic acid and phthalic acid is excellent in the adsorption characteristics of Acid Red 52. However, acrylic acid,
In the case of phthalic acid, experiments were conducted with different amounts of adsorption, but dye fixing compounds treated with acrylic acid at an equivalent ratio of 0.4 or dye fixing compounds treated with phthalic acid at an equivalent ratio of 1.0 The compound is most excellent in adsorption characteristics, and when the equivalent ratio is 1.0 for acrylic acid and 0.4 for phthalic acid, the adsorption characteristics are lower than this.

Therefore, it is suggested that the adsorption characteristics of the dye depend not only on the kind of the organic acid adsorbed on the dye-fixing compound but also on the amount of adsorption.

FIG. 7 shows that the adsorption isotherm of chlorazole black LF shows a tendency to increase even in the range of a large excess of the dye, especially in the dye-fixing compound to which phthalic acid is adsorbed. was gotten.

From the above, it was found that alkenyl acid such as acrylic acid and phthalic acid are suitable as the organic acid adsorbed on the oxide solid solution of hydrotalcite compounds.

The oxide solid solution hydrate that has not been treated with an organic acid has excellent dye adsorbing properties, but when left at room temperature with Acid Red 52 added, the acid The hue of red 52 changes to brown.

On the other hand, a dye-fixing compound in which acrylic acid or phthalic acid is adsorbed and hydrated on an oxide solid solution is
Although a slight change in hue was observed in the case where acrylic acid was adsorbed, it was a degree that hardly caused a problem in practical use.
This is presumed to be because the basicity of the surface of the oxide solid solution hydrate was relaxed by the adsorption of the organic acid.

Examination of printability (2) 20 g of a dye-fixing compound obtained by adsorbing and hydrating various organic acids on an oxide solid solution Mg _0.7 Al _0.3 O _1.15 (Kyowa 2200 manufactured by Kyowa Chemical Industry Co., Ltd.) was added Ethanol solution containing 2% by weight of propylcellulose 1
kg, and dispersed by a roll mill for 7 days.
Then, 1 g of an ultraviolet absorber (Cipro Kasei Co., Ltd.)
A suspension for a receiving layer was prepared by adding trade name (Cesolve 101S).

The suspension for receiving layer was applied to one side of a 110 μm thick white polyethylene terephthalate film using a wire bar. The film has been previously subjected to an antistatic treatment on the surface opposite to the surface coated with the receiving layer suspension. Then, the coating film was dried with hot air at 120 ° C. for 5 minutes to form a 10 μm-thick solid film (receptive layer), thereby preparing a printing sheet.

The printing sheet created in this way is
Printer (product name: HP Deskjet 1200)
C) was mounted on the paper feed tray, and ink jet recording was performed in a color printing mode of three primary colors. Here, in order to perform high-density recording, double printing was performed. In addition, three types of ink liquids were used for yellow, magenta, and cyan, respectively. The mixing ratio of each ink liquid is shown below.

Composition of Ink Liquid Dye 2 parts by weight Tetramethylammonium chloride 1 part by weight Diethylene glycol 5 parts by weight 2-pyrrolidone 15 parts by weight Water 50 parts by weight Any one of the following dyes was used.

Yellow: C.I. I. Acid Yellow 23 Magenta: C.I. I. Acid Red 52 Cyan: C.I. I. Acid Blue 9 The photographic printing paper was evaluated for glossiness, printing density, and temperature and humidity resistance. Table 4 shows the results. The gloss and the temperature and humidity resistance were measured as follows.

Gloss: The gloss of the photographic paper surface was measured by a gloss meter at an incident angle of 45 °.

Printing Density: The reflection optical density (O) of a printing sheet for one color printing and a printing sheet for two color printings
D value).

Temperature / humidity resistance: The printing sheet for one color printing and the printing sheet for two color printings were each heated to a temperature of 60.
It was left for 24 hours in an environment of 90 ° C. and a relative humidity of 90%. Then, ΔE (color difference) before and after standing was determined. The case of ΔE <10 is indicated by “○”, and the case of ΔE ≧ 10 is indicated by “x”.

[0104]

[Table 4]

As shown in Table 4, a printing sheet using a dye-fixing compound treated with 0.4 equivalent of acrylic acid, 1.0 equivalent of phthalic acid, and 0.4 equivalent of salicylic acid has gloss The properties, print density, and temperature / humidity resistance are all good, and superior characteristics can be obtained as compared with a printing sheet using a dye fixing compound treated with another organic acid. However, in the printing sheet using the dye-fixing compound treated with salicylic acid, the dye-fixing compound itself turns brown while the image does not bleed.

Thus, the dye-fixing compound obtained by adsorbing alkenylic acid such as acrylic acid or phthalic acid on the oxide solid solution of the hydrotalcite compound and hydrating it is more susceptible to printing than other dye-fixing compounds. It was found to be excellent as a material for the receiving layer of the sheet.

However, it is desirable that the amount of the organic acid adsorbed on the oxide solid solution is such that the equivalent ratio to the oxide solid solution is 0.2 to 1.1. Table 5 shows, as a typical example, that the equivalent ratio of phthalic acid to the oxide solid solution is 0.05.
The characteristics of a printing sheet using a dye-fixing compound adsorbed so as to be 2.00 are shown, but when the equivalent ratio is as small as 0.05, transparency is impaired. On the other hand, when the equivalent ratio is as large as 2.00, the absorbency of the dye and the resistance to heat and humidity are insufficient.

[0108]

[Table 5]

Investigation of printability (3) In the above experimental examples, the characteristics of the image forming material were evaluated in the form of a print sheet. However, as another form, an image forming material using a postcard as a support was prepared. And its properties were evaluated.

First, a resin solution was prepared by dissolving a polyamide resin (Versamide 725, manufactured by Henkel Hakusui Co., Ltd.) in a solvent according to the following composition. Then, a dye-fixing compound is added to the resin solution, and the mixture is sand-milled.
By dispersing for 4 hours, a spray liquid for the receiving layer was prepared. The dye-fixing compound was prepared by treating an oxide solid solution of a hydrotalcite compound with 0.4 equivalent of phthalic acid and then hydrating the same. Or hydrated by treating with succinic acid, or hydrotalcite oxide solid solution hydrate not treated with an organic acid.

Composition of Spray Solution for Receptive Layer Dye Fixing Compound 1 part by weight Polyamide resin 1 part by weight Solvent 40 parts by weight
A mixed solvent mixed at a weight ratio of 7) The spray liquid for various receptor layers was sprayed on a postcard made by an airbrush and left at room temperature for 20 minutes to form a receptor layer.

The postcard on which the receiving layer was formed in this manner was used as a printer (Printer BJC-trade name, manufactured by Canon Inc.).
420J), and ink jet recording was performed in the color printing mode on the side on which the receiving layer was formed.

As a result, a high-quality natural color image was formed on the receiving layer using the dye-fixing compound to which phthalic acid was adsorbed. The postcard on which this image was formed was left for one week in an environment at a temperature of 60 ° C. and a relative humidity of 90%.
No dot bleeding was observed.

When a stamp image was formed on the receiving layer of this postcard, no bleeding was observed.

On the other hand, in the receiving layer using the dye-fixing compound on which succinic acid is adsorbed, the density of each color is 1/2 to 1 compared with the receiving layer using the dye-fixing compound on which phthalic acid is adsorbed. About / 4. The dots clearly expanded to more than twice the diameter, indicating blurred images.

Further, in the receiving layer using a dye-fixing compound which has not been treated with an organic acid, the hue changes greatly when left at room temperature for one day, and an image far from the original image appears.

[0117]

As is clear from the above description, the image forming material of the present invention has a dye fixing property in which a predetermined organic acid is adsorbed on a hydrotalcite compound or a hydrated product thereof in the receiving layer. Since the compound is contained, it is excellent in transparency and glossiness, and high dye fixability can be obtained even in a severe environment such as high temperature and high humidity.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a layered structure of a hydrotalcite compound.

FIG. 2 is a schematic diagram showing a state in which organic acid ions are held between layers of a hydrotalcite compound.

FIG. 3 is a schematic diagram showing a state where a dye anion is held between layers of a hydrotalcite compound.

FIG. 4 is a characteristic diagram showing an adsorption isotherm of a hydrotalcite compound adsorbing various organic acids to chlorazole black LF.

FIG. 5 is a characteristic diagram showing an adsorption isotherm of a hydrotalcite compound adsorbing various organic acids to chlorazole black LF.

FIG. 6 is a characteristic diagram showing an adsorption isotherm for acid red 52 of a calcined hydrate of a hydrotalcite compound to which various organic acids are adsorbed.

FIG. 7 is a characteristic diagram showing an adsorption isotherm for chlorazole LF of a calcined hydrate of a hydrotalcite compound to which various organic acids are adsorbed.

[Explanation of symbols]

1 Hydrotalcite compounds, 2 layers, 3 inorganic anions, 4 organic acid ions, 5 dye anions

Claims (8)

[Claims] 1. A receiving layer containing a dye-fixing compound in which an organic acid is adsorbed to a hydrotalcite compound represented by the formula 1 or 2; Embedded image The image forming material, wherein the organic acid is any one of phthalic acid, isophthalic acid, terephthalic acid, and maleic acid. 2. The amount of organic acid adsorbed on the hydrotalcite compound is 0.2 to 1.1 in terms of an equivalent ratio of the organic acid to the anion exchange capacity of the hydrotalcite compound.
2. The image forming material according to claim 1, wherein: 3. The image forming material according to claim 1, wherein the receiving layer comprises at least a dye fixing compound, a polymer binder and a solvent. 4. The image-forming material according to claim 1, wherein the amount of the dye-fixing compound contained in the receiving layer is 10 to 90% by weight based on the total solid content in the receiving layer. 5. A fired body of a hydrotalcite compound represented by Chemical Formula 3 or 4 having an acceptor layer containing a dye-fixing compound obtained by hydrating an organic acid by adsorbing an organic acid. ] Embedded image The image forming material, wherein the organic acid is alkenyl acid, phthalic acid or a derivative thereof. 6. The amount of the organic acid adsorbed on the calcined product of the hydrotalcite compound is from 0.2 to 1 in an equivalent ratio of the organic acid to the anion exchange capacity of the regenerated hydrotalcite compound. 7. The method according to claim 5, wherein
The image forming material as described in the above. 7. The image forming material according to claim 5, wherein the receiving layer comprises at least a dye fixing compound, a polymer binder and a solvent. 8. The image-forming material according to claim 5, wherein the amount of the dye-fixing compound contained in the receiving layer is from 10 to 90% by weight based on the total solid content in the receiving layer.