JP2000127610A - Ink-jet recording sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent yellowing of a white sheet and to obtain good fixability of a pigment ink, excellent durability of an image and a high quality by using porous starch particles in an ink receptive layer, and further embedding inorganic or organic fine particles in pores of the porous starch particles. SOLUTION: Porous starch particles are subjected to a water repellent treatment by covering the particles with water repellent resin such as a silicone resin, fluororesin, acrylic resin or the like. The particles can be modified and improved by charging the particles to a cation by using a cationic substance such as γ-glycidyl-propyltrimethyl ammonium chloride or the like. In the case of water repellent-lipophilizing treatment, an ink absorbency of an oil soluble ink can be improved. A dot diameter of the water soluble ink is regulated to obtain the ink-jet recording sheet having a high definition and a high resolution. At the time of cationizing treatment, since fixability of a color material of the water soluble ink is improved, the recording sheet having excellent water resistance of an image can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording sheet, and more particularly to an ink jet recording sheet having good image density and ink absorbability, improved yellowing of white paper, improved fixability of pigment ink, and improved water resistance of the image. The present invention relates to an ink jet recording sheet having excellent properties.

[0002]

2. Description of the Related Art Ink jet recording systems are based on various operating principles typified by a deflection system, a cavity system, a thermojet system, a bubble jet system, a thermal inkjet system, a slit jet system and a spark jet system. In this method, droplets are made to fly and adhere to an ink jet recording sheet such as paper to record images and characters. It has the advantages of high speed, low noise, easy multi-coloring, great flexibility in recording patterns, no need for development-fixing, and various other uses as a recording device for various figures and color images including kanji. Spreading rapidly.

Further, an image formed by an ink jet recording method using a multicolor ink containing a coloring material such as yellow, magenta, cyan, and black in a solvent such as water or a hydrophilic solvent is often used in a plate making method. It is possible to obtain a recorded image comparable to color printing. Further, in applications requiring a small number of copies, it is being widely applied to the field of full-color image recording because it is less expensive than development by silver halide photography.

With the recent technological development, the ink jet recording system is applied to various uses. However, if it is limited to the output use as a hard copy, (1) general use (home use, hobby), (2) OA use (Office use) and (3) business use (EA, FA)
Especially, 400 dpi (16 dots / mm) for business use
The above-mentioned high-definition hard copy is required, and the penetration rate of the ink jet recording system is also increasing.

In particular, high-definition hard copies obtained by the ink-jet recording method are effective as substitutes for silver halide photography, and the storage stability of the ink-jet recording sheet as well as the color reproducibility and gradation of the image is improved. This is an important required characteristic. Here, the storage stability of the ink jet recording sheet is roughly classified into, for example, fading, discoloration and bleeding of the image area (storage stability of the image area), fading and discoloration of white paper (storage stability of white paper), and the like. .

[0006] The storage stability of the image area in particular is known from the conventionally known water-soluble dyes, for example, as disclosed in
Nos. 10660, 57-10661, JP-A-4-234467, 5-156189,
JP-A-5-179183, JP-A-5-202324, JP-A-5-263029, JP-A-5-331313, JP-A-6-122846, and JP-A-6-1363111
It is known that the light fastness, ozone fastness and water fastness are drastically improved by changing to a pigment having a high fastness as proposed in Japanese Patent Application Laid-Open No. H10-163,078.

Further, for example, Japanese Patent Publication Nos. 7-78187, 7-78188, 8-6057,
Naphthol dyes, azo dyes, metal complex dyes, anthraquinone dyes, quinoimine dyes, indigo dyes, cyanine dyes, such as those proposed in JP-A-8-26259, JP-A-6-247034 and JP-A-6-306319. By changing to oil-soluble dyes such as quinoline dyes, nitro dyes, nitroso dyes, benzoquinone dyes, carbonium dyes, naphthoquinone dyes, naphthalimide dyes, phthalocyanine dyes, and perinine dyes, the image density is high, the coloration is excellent, and water resistance is high. And an ink jet recording sheet having good cockling resistance is obtained.

As described above, regarding the storage stability of the image area, it has been recognized that it is important to comprehensively study not only the ink jet recording sheet but also the improvement of the ink, and the storage stability has been substantially improved.

On the other hand, with respect to the storage stability of white paper, improvement of yellowing is a main subject to be studied. Here, the yellowing of the blank paper is
It can be caused not only by light, ozone, NO _x , heat, humidity, etc. but also by certain antioxidants.
In particular, the latter is known to occur when a high definition hard copy is bound to a file and stored, or when an adhesive tape is adhered to the surface of the ink receiving layer. This problem is very important in that the ink jet recording system can substitute for silver halide photography, and although various improvements have been studied, in reality, sufficient ink jet recording sheets have not yet been obtained. Was.

As an ink jet recording sheet, the image density is high, the color tone is bright and vivid, the ink absorption is fast, the ink does not flow or bleed even when the dots overlap, It is necessary to satisfy various requirements such as that the diffusion does not become larger than necessary, that the dot shape is close to a perfect circle, the periphery is smooth and not blurred, and that the whiteness is high. Japanese Patent Application Laid-Open No. 60-232990 discloses a method in which a synthetic amorphous silica or a salt thereof, or a mixture thereof is coated on a paper surface together with a binder resin as necessary, or is filled therein. High-quality cationic hydrated aluminum oxide, and further disclosed in JP-A-60-204390 and JP-A-2-198889. Etc. The publication, by allowed to contain a large synthetic amorphous silica and a cationic hydrated aluminum oxide is cationic colloidal particles of specific surface area by the BET method, it is possible to achieve the object.

However, in these conventionally known ink jet recording sheets, the yellowing of the white paper as described above was strong. In order to pursue image density and color development, simply using synthetic amorphous silica with a large specific surface area,
When the colloidal particles of alumina hydrate having a pseudo-boehmite structure were used to improve the water resistance of the image, the yellowing of the white paper was particularly deteriorated. In general, when a cationic material is used for the purpose of improving the water resistance of an image, yellowing of white paper is severe, and there has been no ink jet recording sheet that can satisfy both of these problems.

[0012] The yellowing of white paper of such an ink jet recording sheet is, for example, 2,6-di-tert-butyl-
When the recording sheet is bound and stored in a clear file containing 4-methyl-phenol (hereinafter, referred to as BHT), it can be assumed that BHT is generated by transferring from the clear file to the ink receiving layer of the recording sheet. Therefore,
When a familiar article containing a phenolic antioxidant typified by BHT comes into contact with an ink jet recording sheet, yellowing proceeds, and the yellowing progresses due to secondary factors such as ozone, NO _x , SO _x and temperature and humidity in the air. It is expected to be promoted.

Incidentally, the yellowing caused by BHT is described in, for example, Polymer Degradation.
and Stability 50 (1995) 31
3-317, Textil Praxis Inter
national Oktober (1980) 121
3-1215, Textil Praxis Inte
national Marz (1983) 261-
264, Textile Chemist and C
orolist April (1983) Vol. 1
5 No4 52-56 and Text. Progr. Fifteen
(1987) 16, etc., and especially in the textile and apparel industries, there has been a history of being taken up as a problem for a long time, and has been found to be a compound having a stilbenequinone structure through an oxidation reaction. .

As an interesting proposal, in particular, Japanese Patent Laid-Open Publication No. 1-22
2987 gazette. According to the proposal, the dye in the ink is tested by a spot test using [4,4'-methylene-bis-2,6- (di-tert-butylphenol)] (hereinafter referred to as BHT2) on an ink jet recording sheet. A method for evaluating the catalytic activity of a porous ink receiving layer when is decomposed by oxygen is described. In this BHT2 spot test, BHT2 was oxidized,
This is due to the fact that the stilbenequinone structure is colored yellow when it is formed, and a correlation has been found between the results of the test and indoor discoloration of a printed image on an inkjet recording material.

Further, in the proposal, as a preferred coat layer, that is, a form of the ink receiving layer, which has a small yellowing in the BHT2 spot test, a metal selected from the group consisting of Mg, Ca, Zn, and Ba is 0.1% by weight. It is described that the above-mentioned silicon-containing pigment is contained in the recording surface, that is, in the ink receiving layer, but it is described that it also has the side effect of lowering the image density. In order to improve this side effect, it has also been proposed to use a cationic substance in combination.However, it is described that light resistance is reduced, and the problem of storage stability of an image in an ink jet recording sheet is described. It has been known for some time that a phenolic antioxidant represented by BHT is involved.

Further, when the BHT transferred to the ink receiving layer turns yellow, the degree of the yellowing varies depending on the material and composition of the ink jet recording sheet, but particularly greatly affects the pigments and colloid particles constituting the ink receiving layer. What is done can be seen from what is stated in the proposal above.

Further, when the pigment ink as described above is used, there is a problem that the fixability of an image is poor. In particular, in the latter problem, the pigment ink may be scraped off even when the image portion is lightly touched, and it may not be usable for hard copy use.

[0018]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an ink jet recording sheet having a good image density and ink absorbency as well as a conventionally known ink jet recording sheet. In particular, a hard copy obtained by ink jet recording is bound to a file, for example. A high-quality inkjet recording sheet with improved yellowing of white paper that occurs when storage is performed or when an adhesive tape is adhered to the ink-receiving layer, good fixability of the pigment ink, and excellent image water resistance. Is to provide.

[0019]

As a result of the present inventors' intensive studies on the above-mentioned problems in the ink jet recording sheet, the high definition hard copy obtained by the ink jet recording is bound in a file and stored. Or
Alternatively, it could be inferred that the yellowing of white paper, which occurs when the adhesive tape is attached to the ink receiving layer, is due to a phenolic antioxidant represented by BHT contained in the file or the adhesive tape. .

Typical examples of these phenolic antioxidants include BHT (Sumilyzer BHT: Sumitomo Chemical, Yoshinox BHT: Yoshitomi Pharmaceutical,
Andage BHT: Kawaguchi Chemical), n-octadecyl-3
-(3 ', 5'-di-tert-butyl-4'-hydroxyphenyl) propionate (Irganox 107
6: Ciba-Geigy, ADK STAB AO-50: Asahi Denka,
Sumilizer BP-76: Sumitomo Chemical, Tominox S
S: Yoshitomi Pharmaceutical), 4,4′-butylidenebis- (3-methyl-6-tert-butylphenol) (ADEKA STAB AO-40: Asahi Denka, Sumilizer BBM-S: Sumitomo Chemical, Yoshinox BB: Yoshitomi Pharmaceutical, Antage W30
0: Kawaguchi Chemical, Knock Riser NS30: Ouchi Emerging, Non-Flex BB: Seiko Chemical), and the like.

As a result of further intensive studies by the present inventors on a method for improving the yellowing of white paper caused by the above-mentioned phenolic antioxidant, it was found that instead of the conventionally known pigment and colloid particles constituting the ink receiving layer, It has been found that the use of porous starch particles can improve the yellowing of white paper without impairing inkjet recording characteristics such as image density and ink absorbency. Further, by embedding inorganic or organic fine particles in the pores of the porous starch particles, the water resistance of the image could be improved. this is,
The coloring material (dye) in the ink that penetrates into the pores of the porous starch particles and is absorbed by the embedded fine particles bleeds between the embedded fine particles even when carelessly wetted with water or the like. However, it can be inferred that the porous starch particles do not diffuse and bleed even in the starch membrane wall.

Further, such porous starch particles are effective not only in a so-called coated paper type ink jet recording sheet provided with an ink receiving layer but also in a non-coated type ink jet recording sheet. Was found. In the non-coated type ink jet recording sheet, usually, for the purpose of improving opacity and improving image density and ink absorption, synthetic amorphous silica, light calcium carbonate, heavy calcium carbonate, kaolin, talc,
Calcium sulfate, barium sulfate, titanium dioxide, zinc oxide, zinc sulfide, zinc carbonate, satin white, aluminum silicate, diatomaceous earth, calcium silicate, magnesium silicate, aluminum hydroxide, alumina, lithopone, zeolite, hydrohaloisite, magnesium carbonate, water Pigments (fillers) typified by magnesium oxide are often included, but by replacing all or part of these pigments with the porous starch particles as described above, high quality can be achieved as in coated paper types. Thus, a non-coating type ink jet recording sheet could be obtained.

In recent ink jet recording systems, light fastness, water fastness, ozone fastness, NO _x ,
In order to improve the storage stability, such as SO _x resistance, the use of pigment ink as described above is increasing. However, when inkjet recording is performed using a pigment ink, there has been a problem in the fixability of image recording in a conventionally known inkjet recording sheet. Generally, when the ink containing the pigment having a particle diameter of about 0.05 to 0.5 μm flies and lands on the recording sheet surface, many of the pigments do not penetrate into the inside of the sheet and accumulate on the surface. This is a problem that arises.

According to the intensive studies of the present inventors, such a problem could be improved by using the above-described porous starch particles. Since the pores of the porous starch particles are appropriately larger than conventionally known pigment and colloid particles, the penetration of the pigment ink is performed quickly. Here, the solvent of the pigment ink is absorbed by the fine particles embedded in the pores of the porous starch particles, while most of the pigment is deposited on the surface of the embedded fine particles. Therefore, for example, even when rubbed with a hand, the pigment that has entered the pores of the porous starch particles is not scraped off, and the image density is high.

That is, the first ink jet recording sheet of the present invention is an ink jet recording sheet obtained by making a slurry containing natural or synthetic fibers as a main component. In the sheet, inorganic or organic fine particles are contained in pores. An ink jet recording sheet comprising porous starch particles having embedded therein.

Here, the fine particles are JIS-K5101.
When the fine particles have an oil absorption of 30 ml / 100 g or more, more preferable image density, ink absorbency, pigment fixability and water resistance of the image can be achieved.

In particular, when the fine particles are at least one kind of fine particles of silica or alumina, more excellent image density, ink absorbency, pigment fixing property and image water resistance can be achieved.

The second ink jet recording sheet of the present invention is an ink jet recording sheet having an ink receiving layer provided on at least one surface of a support, wherein the ink receiving layer is mainly composed of inorganic or organic pores. An ink jet recording sheet comprising a porous starch particle having fine particles embedded therein and a binder resin.

Here, the fine particles are JIS-K5101.
When the fine particles have an oil absorption of 30 ml / 100 g or more, more preferable image density, ink absorbency, pigment fixability and water resistance of the image can be achieved.

In particular, when the fine particles are at least one kind of fine particles of silica or alumina, more excellent image density, ink absorbency, pigment fixability and water resistance of the image can be achieved.

[0031]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The ink jet recording sheet of the present invention will be described below in detail. Porous starch particles used in the inkjet recording sheet of the present invention, for example, (1)
Monma, Kainuma et al .: Starch Chemistry, Vol. 37, no. 1, p
13-19 (1990), (2) Gate: Starch Chemistry, Vo
l. 38, no. 1, p45-50 (1991), (3)
Monma, Kainuma: Agric. Biol. Chem. , 5
3,1503-1508 (1989), (4) Fuwa, Tanaka et al .: Starke, 30, 186 (1978), (5) Tanaka, Sugimoto et al. Jap. Soc. Starch Sc
i. , 29, 287 (1982), (6) Suzuki: Reprinted monthly edition of Food Chemical October (1997), (7) Suzuki: Food and Chemistry, Vol. 37, no. 1 (1995), (8) Hasegawa: Abstracts of the 3rd and 4th Granulation Subcommittee Technical Discussion Meeting, 1997, (9) JP-A-5-112469 and (10) 8
These are starch particles having a plurality of holes formed on the surface as illustrated in, for example, Japanese Patent Application No. -277230.

The porous starch particles illustrated in the above-mentioned documents include, for example, modified corn such as wheat, corn, hydroxypropylated corn, potato, non-glutinous rice, rice cake, waxy corn, sweet potato, sago, tapioca, Peas, red beans, mung bean, cycads,
For various starch particles such as sorghum and banana, for example, α-amylase, β-amylase, glucoamylase, pullulanase, R enzyme, isoamylase, phosphorylase, transglucosidase, amylo-1,6-glucosidase, oligo-1, 6-glucosidase, maltase, takamaltase, γ-amylase, takaamylase B, glucamylase, amyrosinase, phosphorylase, D enzyme, amylosucrase, glycogen transglucosidase, amylose isomerase,
It is obtained by reacting a raw starch-degrading enzyme such as Q enzyme, Z enzyme, limiting dextrinase, amylose isomerase and the like.

Here, the raw starch-degrading enzyme is, specifically, α-amylase, which can be purified from pig pancreas, human saliva, human pancreas, barley malt, etc.
-Amylase can be purified from barley malt, sweet potato, wheat flour and the like. Also, for example,
Aspergillus awamori, Rhizo
pus sp. A. awamori var. kaw
achii, A .; cinnamomeus, Bacil
plus cruculans F-2, Chalara
paradoxa or Aspergillus sp.
It can also be produced from a group of microorganisms represented by K-27 and the like.

The porous starch particles used in the ink jet recording sheet of the present invention can be satisfactorily achieved as long as they are porous starch particles. Therefore, the production method is not particularly limited. Suitable for large-volume productivity such as simplicity of the reaction, and because the pore size and porosity of the resulting porous starch particles are also appropriate, particularly, for corn starch particles, waxy corn starch particles, It is a raw starch-degrading enzyme separated from sago palm stems against porous starch particles and corn starch particles produced by the action of glucoamylase or α-amylase produced by microorganisms represented by Chalara paradoxa and corn starch particles. Porous starch particles having pores formed by the action of glucoamylase can be suitably used.

An example of a method for producing such porous starch particles will be described. The aqueous suspension solution of corn starch particles was adjusted to pH 4
Adjust to ５5, keep the temperature at 30-40 ° C., then add the amylolytic amylase enzyme. The decomposition of the starch particles progresses with time, the pores gradually increase, and the porosity also increases. The enzymatic reaction is completed in about 15 to 30 hours. After the reaction, the decomposed sugars are removed by washing, and dried at 60 ° C. or lower using a spray drier or a flash jet drier to obtain porous starch particles.

One example of the physical properties of the porous starch particles thus obtained is as follows: a particle diameter of 1 to 30 μm, and an average pore diameter of 0.1.
-10 μm, porosity 10-90%, pore volume 1-8 ml
/ 100g, pore area 100~300m ² / 100g,
The oil absorption specified in JIS-K5101 is 50 to 200
ml / 100 g.

As described above, the porosity of the porous starch particles can be adjusted by adjusting the temperature of the enzyme reaction and the treatment time.
In the ink jet recording sheet of the present invention, it is particularly preferable to use porous starch particles having a porosity of 30 to 80%. Here, if the porosity is less than 30%, it becomes difficult to efficiently embed the inorganic or organic fine particles as described below, and the image density and the ink absorbency decrease. Not only does the image quality deteriorate, but it becomes impossible to develop sufficient water resistance of the image. On the other hand, when the porosity exceeds 80%, the mechanical strength of the porous starch particles is remarkably reduced. Therefore, when the fine particles are embedded or mixed and dispersed with various materials as a coating liquid for the ink receiving layer, the starch is used. The particles are liable to be crushed, which is not preferable.

Further, the above-mentioned porous starch particles are
For example, the surface of the particles can be modified or modified by using a spray dryer equipped with a coating nozzle. If you show a typical example of modification / modification,
The particles are coated with a water-repellent resin such as a silicone resin, a fluorine-based resin, or an acrylic resin, and subjected to a water-repellent treatment, and a cationization treatment is performed using a cationic substance such as γ-glycidylpropyltrimethylammonium chloride. Modification / modification such as application can be performed. here,
When water-repellent / lipophilic treatment is applied, it is possible to improve the ink absorbency of the oil-soluble ink as described below, and to adjust the dot diameter of the water-soluble ink to achieve high-definition and high-resolution inkjet recording. You can also get a sheet. On the other hand, when the cationization treatment is performed, the fixability of the coloring material in the water-soluble ink is improved, so that an ink jet recording sheet having excellent water resistance of an image can be obtained.

Inorganic or organic fine particles are embedded in the pores of the porous starch particles as described above. Here, the fine particles include, for example, fine light calcium carbonate, heavy calcium carbonate, kaolin, talc, calcium sulfate, barium sulfate, titanium dioxide, zinc oxide, zinc sulfide, having an average particle diameter of about 0.1 to 5 μm. Conventionally known pigments (fillers) such as zinc carbonate, satin white, aluminum silicate, diatomaceous earth, calcium silicate, magnesium silicate, aluminum hydroxide, alumina, lithopone, zeolite, hydrohaloysite, magnesium carbonate, magnesium hydroxide, silica and alumina Fine particles, alumina hydrate (pseudo-boehmite sol), colloidal silica, silica / alumina hybrid sol, smectite clay such as hectite, montmorillonite, zirconia sol, chromia sol, yttria sol, ceria sol, iron oxide sol, zircon , Colloidal particles such as antimony oxide sol, acrylic or methacrylic resin, vinyl chloride resin, vinyl acetate resin, polyester resin, styrene / acrylic resin, styrene / butadiene resin, polystyrene / acrylic resin, polystyrene Polymer beads such as / isoprene resin, methyl methacrylate / butyl methacrylate resin, polycarbonate resin, silicone resin, urea resin, melamine resin, epoxy resin, phenol resin and diallyl phthalate resin. it can. These fine particles can be embedded by mixing two or more kinds.

Here, in particular, by embedding polymer beads or the like having high lipophilicity or oil swelling property,
In ink jet recording using an oil-soluble ink, it is also possible to obtain an ink jet recording sheet with improved image bleeding and image strikethrough.

Of the inorganic or organic fine particles as described above, the use of fine particles having an oil absorption of 30 ml / 100 g or more specified in JIS-K5101 is particularly preferred in the first and second ink jet recording of the present invention. The image density of the sheet, the fixability of the pigment ink, and the water resistance of the image are further improved.

Further, among the above-mentioned inorganic or organic fine particles, when fine particles selected from at least one of silica and alumina are used, the first and second ink jet recording sheets of the present invention can be used. Improves image density, pigment ink fixability and image water resistance. Accordingly, silica or alumina fine particles having an oil absorption of 30 ml / 100 g or more specified in JIS-K5101 are even more preferable.

Here, the silica fine particles can be produced by a method such as an electric arc method, a dry method, a wet method (precipitation method or gel method), and have a particle diameter of 0.1 to 5 μm by a Coulter counter method. , Specific surface area by BET method is 20m ²
/ G, more preferably 50 to 400 m ² / g, and a Hunter whiteness of 90 or more is preferred. Specific examples of such silica fine particles include:

1) For example, synthetic silica or a salt thereof or a mixture thereof (JP-A-55-51583,
JP-A-57-157786.

2) Synthetic silica having an average particle size of 2.5 to 3.5 μm, a specific particle size distribution, and having pores in the range of 60 to 130 angstroms of 20% or more of all the pores (JP-A No. No. 61-141584)

3) The pH of the 4% by weight aqueous suspension is 9-1.
2. Electric conductivity 400 to 1,000 micromho / cm
And the chemical composition ratio of Ni / SiO ₂ is 0.02
~ 0.04 synthetic amorphous silica (JP-A-61-23)
0979 publication)

6) The specific surface area measured by the BET method is 200
Fine-grained silica having m ² / g or more and a number n of 1.10 or more such as rosin-Rammler distribution (JP-B-3-26665)

7) Alkali impregnation having a BET specific surface area of 200 m ² / g or more, an oil absorption of 180 ml / 100 g or more, and an acid amount up to acid strength (H ₀ ) +4.8 of 0.1 mmol / g or less. Amorphous silica (JP-A-5-6495)
No. 3).

Examples of the alumina fine particles include crystalline alumina fine particles such as α-alumina, β-alumina, and γ-alumina, and alumina hydrate fine particles represented by a composition formula of Al ₂ O ₃ .nH ₂ O ( In the formula, when n is 1, it represents an alumina hydrate having a boehmite structure, and n is 1
When n is more than 3 and less than 3, the alumina hydrate has a pseudo-boehmite structure, and when n is more than 3, the alumina hydrate has an amorphous structure. Here, the particle diameter of the α, β, γ-alumina fine particles by the Coulter counter method is 0.1 to 5 μm,
Specific surface area according to law 20 m ² / g or more, more preferably one having 50 to 400 m ² / g.

On the other hand, as the alumina hydrate, an average particle diameter of 1 to 10 nm, BET specific surface area of 70m ² / g or more, more preferably one having a 70~300m ² / g. Such an alumina hydrate can be obtained by hydrolysis of an aluminum alkoxide such as aluminum isopropoxide, neutralization of an aluminum salt with an alkali, hydrolysis of an aluminate, as described in JP-A-56-120508. A method in which the pH is alternately changed to the acid and base sides to grow alumina hydrate crystals, alumina hydrate obtained from an inorganic salt of aluminum, as described in JP-B-4-33728, Alumina obtained by the Bayer method is mixed with a sol of alumina hydrate produced by a known method such as a method of rehydrating alumina, and those obtained by pulverizing the sol using a granular dryer such as a spray dryer. Can be mentioned. More specifically about alumina hydrate,

1) When a sol diluted to a solid content of 0.01 to 0.1% by weight with water is dropped on a hydrophilic collodion film and dried, the particles have an aspect ratio of 2 to 10%.
Alumina sol in the form of a plate (Japanese Patent Laid-Open No. 3-285814)

2) Alumina sol having a columnar particle shape having an aspect ratio of 2 or less in a state where a sol diluted to a solid content of 0.01 to 0.1% by weight with water is dropped on a collodion film hydrophilized and dried. (JP-A-3-285815)

3) Alumina sol produced by a method for producing a boehmite organosol in which a surfactant is added to a boehmite hydrosol and then transferred into a non-polar organic solvent (Japanese Patent Application Laid-Open No. Hei 4-92913).

4) An aqueous solution of alkali aluminate is introduced into a desalting chamber of an electrodialysis tank having an alkali-resistant anion exchange membrane and a cation exchange membrane alternately, and a caustic alkali aqueous solution is introduced into a concentration chamber. Sol produced by a method of obtaining alumina sol by performing
No. 2, No. 7-803)

5) A sol in which colloidal particles of alumina hydrate are dispersed in an aqueous solvent, containing a compound having a sulfonic acid group in the molecule and having a pH of 4 or less when converted to a 1% by weight aqueous solution. Alumina sol (JP-A-8-33315)

6) In a method of producing an alumina sol by hydrolyzing an aluminum alkoxide in an aqueous solvent to obtain a precipitate of alumina hydrate, and further pulverizing the precipitate to form an alumina sol, the aluminum alkoxide is hydrolyzed while removing alcohol in the solvent. Alumina sol produced by a method for producing an alumina sol that undergoes decomposition (Japanese Patent Application Laid-Open No. 6-64918)

7) When cations other than hydrogen ions are contained in the range of 2.0 × 10 ^{-4 to} 1.0 × 10 ^-1 N in the sum of the specified number of ions, and when the concentration of alumina is 10% by weight or more, Alumina sol having a viscosity of 5000 cps or less measured with a Brookfield viscometer (Japanese Patent Laid-Open No. 8-295509)

8) The plane interval of the (020) plane of the alumina hydrate is more than 0.167 nm and 0.620 nm or less;
And the crystal thickness in the direction perpendicular to the (010) plane is 6.0 to 1
Alumina sol having a boehmite structure characterized by being in the range of 0.0 nm (JP-A-9-99627)

9) Alumina hydrate having an average pore radius of 20 to 200 angstroms and a pore size distribution having a half width of 20 to 150 angstroms (JP-A-7-2324)
No. 75)

10) 0.01 to 1.00 titanium dioxide
% By weight of alumina hydrate (JP-A-7-23247)
No. 4)

11) Alumina hydrate having two or more maxima in the pore radius distribution (JP-A-7-232473)
And the like.

As a method of embedding the above-mentioned various fine particles in the pores of the porous starch particles, for example, a method of mechanically mixing the fine particles to be embedded with the porous starch particles using a paint conditioner, a ball mill or the like. For the purpose of increasing the embedding efficiency, for example, water, methanol, ethanol, lower alcohols such as isopropanol, ethylene glycol, diethylene glycol, glycols such as propylene glycol and other organic solvents may also be added. it can. After the mixing treatment, it is preferable to classify and separate the various fine particles remaining without being embedded to remove them.

The porous starch particles having various fine particles embedded therein may be added to a slurry for producing the first ink jet recording sheet of the present invention, or may be added to the second ink jet recording sheet of the present invention. When embedded in the ink receiving layer coating solution for producing the sheet, the embedded fine particles are porous so that the fine particles do not flow out or fall out of the pores of the porous starch particles. A binding treatment can be performed on the pores of the starch particles. Here, the binding treatment can be performed, for example, by spraying a binder resin using a spray drier equipped with a coating nozzle or the like, or by infiltrating the binder resin.
Here, as the binder resin for binding the fine particles, the following binder resins used for the ink receiving layer of the second inkjet recording sheet of the present invention can be suitably used.

The preferred embodiment of the ink jet recording sheet of the present invention will be described below. The first ink jet recording sheet of the present invention is a non-coating type having no ink receiving layer, and is a chemical pulp such as LBKP, NBKP; SGW, CGW, TRMP, SCMP, TANDE.
MTMP, GP, PGW, RMP, TMP, CTMP,
Mechanical fibers such as CMP and CGP; natural fibers such as wood pulp such as waste paper pulp such as DIP; synthetic fibers such as polyester, polyurethane, aromatic polyamide, polypropylene, polyethylene, and acrylic; and synthetic fibers such as glass fiber. In the slurry in which the dispersed starch particles contain porous starch particles embedded therein, a fourdrinier paper machine,
It can be obtained by making a paper using various devices such as a round paper machine and a twin wire paper machine, or by using a size press method such as a calendar size or a tab size on the surface of a sheet that has already been made, and embedding fine particles in the porous sheet. The desired inkjet recording sheet can be obtained by infiltrating the basic starch particles.

The content of the porous starch particles in which fine particles are embedded in the first ink jet recording sheet of the present invention is 1 to 200% by weight, more preferably 10 to 100% by weight based on the total amount of natural or synthetic fibers. % By weight. Here, if the content is less than 1% by weight, the ink absorbency is poor, so that it is not preferable. If it exceeds 200% by weight, the characteristic hand of paper or synthetic fiber is impaired, which is not preferable. The difference in the ink absorbency between the part containing the particles and the part not containing the particles is remarkable and not only tends to cause spots in solid images and halftone images, but also decreases the strength of the sheet stiffness, bending property, etc. Disadvantages may be seen.

In the first ink jet recording sheet of the present invention, a sizing agent, a fixing agent, an ink fixing agent, a retention agent, a cationizing agent, a paper-strengthening agent, a fiber deflocculant, a defoaming agent may be used, if necessary. Agents, drainage aids, optical brighteners, bluing agents, pitch inhibitors, bactericides, special chemicals, and other various additives, and the basis weight of the first inkjet recording sheet. Usually, 50 to 30
The one having about 0 g / m ² is used.

Further, for the purpose of making the rigidity, bendability and opacity of the ink jet recording sheet more satisfactory, for example, synthetic amorphous silica, light calcium carbonate, heavy calcium carbonate, kaolin, talc, sulfuric acid Calcium, barium sulfate, titanium dioxide, zinc oxide,
Zinc sulfide, zinc carbonate, satin white, aluminum silicate, diatomaceous earth, calcium silicate, magnesium silicate,
Conventionally known pigments (fillers) such as aluminum hydroxide, alumina, lithopone, zeolite, hydrohaloysite, magnesium carbonate, and magnesium hydroxide can be used in combination as long as the object of the present invention is not hindered.

The first ink jet recording sheet of the present invention can be subjected to calendar processing such as a machine calendar, a super calendar, a gloss calendar, a mat calendar, a friction calendar, and a brush calendar. Further, a size press such as a calendar size or a tab size can be appropriately performed for the purpose of penetrating a drug such as a dot diameter adjusting agent and a release agent into the sheet surface.

The second ink jet recording sheet of the present invention is of a coating type in which an ink receiving layer is provided on a support, and the ink receiving layer contains porous starch particles having fine particles embedded therein. It becomes. In the ink receiving layer, in addition to the porous starch particles in which fine particles are embedded, it is necessary to contain a binder resin in order to enhance the adhesion between the particles or between the particles and the support. The content of the binder resin is preferably from 0.1 to 100% by weight, more preferably from 1 to 50% by weight, based on the porous starch particles in which the fine particles are embedded. Here, when the content of the binder resin is less than 0.1% by weight, the adhesive force between the porous starch particles in which the fine particles are embedded or between the particles and the support is weak, and such a problem that the particles fall off occurs. easy. Also 10
When the content exceeds 0% by weight, the pores of the porous starch particles in which the fine particles are embedded are buried with the binder resin, and adverse effects such as a decrease in image density and ink absorbability are likely to occur.

Examples of binder resins that can be suitably used include polyvinyl alcohol, silanol-modified polyvinyl alcohol, polyvinyl acetate, oxidized starch, etherified starch, cellulose derivatives such as carboxymethyl cellulose and hydroxyethyl cellulose, casein, gelatin, acidic Gelatin, soy protein, silyl-modified polyvinyl alcohol, etc .; maleic anhydride resin, styrene-butadiene copolymer, methyl methacrylate-
Conjugated diene copolymer latex such as butadiene copolymer; acrylic polymer latex such as acrylic acid and methacrylic acid ester polymer or copolymer, acrylic acid and methacrylic acid polymer or copolymer; ethylene -Vinyl polymer latex such as vinyl acetate copolymer; or functional group-modified polymer latex by monomer containing functional group such as carboxyl group of these various polymers; Thermosetting synthetic resin such as melamine resin and urea resin -Based water-soluble adhesives; synthetic resin-based adhesives such as polymethyl methacrylate, polyurethane resin, unsaturated polyester resin, vinyl chloride-vinyl acetate copolymer, polyvinyl butyral, and alkyd resin, used alone or in combination. be able to. In addition, the use of a known natural or synthetic resin binder alone or in combination is not particularly limited.

As an ink jet recording sheet, the image density is high, the color tone is bright and vivid, the ink absorption is fast, the ink does not flow or bleed even when the dots overlap, It is necessary to satisfy various requirements, such as that the diffusion does not become larger than necessary, the shape of the ink dots is close to a perfect circle, the periphery is smooth and not blurred, and the whiteness is high. In general, it can be achieved by using the porous starch particles prepared as described above, but in some cases, more preferable ink jet recording is carried out by including pigments or colloid particles, or a mixture thereof, together with the porous starch particles having embedded fine particles. You can also get a sheet.

Here, pigments can be broadly classified into inorganic pigments and organic pigments. As inorganic pigments, for example, synthetic amorphous silica, light calcium carbonate, heavy calcium carbonate, kaolin, talc, calcium sulfate, barium sulfate, titanium dioxide, zinc oxide, zinc sulfide, zinc carbonate, satin white, aluminum silicate, Diatomaceous earth, calcium silicate, magnesium silicate, aluminum hydroxide, alumina, lithopone, zeolite, hydrohaloysite, magnesium carbonate, magnesium hydroxide and the like can be mentioned. In the second inkjet recording sheet of the present invention, one or more of these inorganic pigments may be mixed and contained in the ink receiving layer.

On the other hand, white or colorless polymer beads can be suitably used as the organic pigment.
For example, acrylic or methacrylic resin, vinyl chloride resin, vinyl acetate resin, polyester resin,
Styrene / acrylic resin, styrene / butadiene resin, polystyrene / acrylic resin, polystyrene / isoprene resin, methyl methacrylate / butyl methacrylate resin, polycarbonate resin, silicone resin, urea resin, melamine resin, epoxy Spherical or amorphous non-porous or porous beads made of at least one resin such as a series resin, a phenol series resin, and a diallyl phthalate series resin. Of course, one or more of the above-mentioned inorganic pigments and one or more of the organic pigments can be mixed and contained together with the porous starch particles in which fine particles are embedded.

Further, in the ink receiving layer of the second ink jet recording sheet of the present invention, other additives such as a cationic dye fixing agent, a crosslinking agent, a pigment dispersant, a thickener, a fluidity improver, Antifoaming agent, foam inhibitor, release agent, foaming agent,
Penetrants, coloring dyes, coloring pigments, fluorescent whitening agents, ultraviolet absorbers, preservatives, anti-binders, water-proofing agents, antioxidants and the like can also be added as appropriate.

Examples of the support of the second ink jet recording sheet of the present invention include: a) Chemical pulp such as LBKP, NBKP, GP, PG
Mechanical pulp such as W, RMP, TMP, CTMP, CMP, CGP, natural pulp such as waste paper pulp such as DIP, and conventionally known pigments as main components, binder, sizing agent, fixing agent, retention improver, cationizing agent Papers (base papers) made by using a slurry obtained by mixing one or more kinds of additives such as a paper strength enhancer with various apparatuses such as a fourdrinier paper machine, a circular net paper machine, and a twin wire paper machine;

B) Paper (base paper) such as base paper having a size press with starch or polyvinyl alcohol or an anchor coat layer, art paper, coat paper, cast coat paper or the like having a coat layer provided thereon; Coated papers;

C) Machine calendar, TG calendar,
Paper (base paper) that has been subjected to a smoothing process using a calendar device such as a soft calendar;

D) resin-coated paper in which high-density, low-density polyethylene, polypropylene, polyester, or the like is coated on both sides or one side of paper (base paper) or coated paper by a melt extrusion method or the like;

E) (Transparent) synthetic resin films such as polyethylene terephthalate, polypropylene, polyethylene, polyester, polycarbonate, norbornene, vinylon, polyvinyl alcohol, nylon and the like, and pigments and foaming agents are contained in these materials to reduce the transparency. Translucent or opaque synthetic resin films;

F) Thermoplastic resins such as polyethylene, polypropylene, ethylene / propylene copolymer, ethylene / vinyl acetate copolymer, polystyrene and polyacrylates and inorganic pigments such as calcium carbonate, talc, silica and calcined clay Mixed paper stretched and laminated;

G) Alternatively, it is possible to suitably use those having improved adhesion, such as a corona discharge treatment, a flame treatment, a plasma treatment, and an anchor layer coating treatment, on the surface of these supports.

Further, these supports can be subjected to calender treatment such as machine calender, super calender, gloss calender, mat calender, friction calender, brush calender and the like. The support has a basis weight of usually about 50 to 300 g / m ² .

The coating amount of the ink receiving layer is not particularly limited, but is preferably 1 to 50 g / m ² . A coating amount of less than 1 g / m ² is not preferable because sufficient image density and ink absorbency cannot be obtained, and a coating amount of more than 50 g / m ² deteriorates curl properties of the ink jet recording sheet, and is therefore preferable. Absent.

As a method of providing the ink receiving layer on the support, water, a hydrophilic organic solvent, a mixed solvent thereof, or an organic solvent may be used, for example, a conventionally known air knife coater, curtain coater, die coater, or the like. Coating can be performed on the support by various devices such as a lip coater, blade coater, gate roll coater, bar coater, rod coater, roll coater, bill blade coater, short dwell blade coater, size press, and shim sizer.

Here, the ink receiving layer may be applied in a certain amount of application in several times. Here, as a method of applying the ink receiving layer by dividing it into several times, a method of drying and applying each layer and a method of applying a plurality of layers simultaneously by wet-on-wet are mentioned. Can be.

Further, after coating the ink receiving layer, a machine calendar, a TG calendar, a super calendar,
The smoothing process can be performed using a calendar device such as a soft calendar.

When paper (base paper) is used as the support, a back coat layer for imparting curl aptitude can be applied to the opposite surface of the ink receiving layer with the support interposed therebetween. In this case, the pigment is preferably a plate-like pigment or hydrohaloysite. Even when a back coat is not provided, the curl can be corrected by injecting water vapor with a humidifier such as Fludex.

In the first and second ink jet recording sheets of the present invention, when the surface pH defined by TAPPI T529 of each of the recording sheet and the ink receiving layer is 6.0 or less, the yellowing of blank paper is further increased. Is suppressed. This is because the yellowing reaction of a phenolic antioxidant represented by BHT or the like is further suppressed in the acidic pH region in combination with the action of the specific porous starch particles of the present invention. Therefore, hydrochloric acid, nitric acid, sulfuric acid,
It is also preferable to lower the pH using an acidic substance such as acetic acid, a sulfuric acid band, aluminum chloride, or polyaluminum chloride.

Here, in the case of the first ink jet recording sheet of the present invention, or in the case of the second ink jet recording sheet, the support is paper (base paper) made from a slurry mainly composed of natural pulp. In this case, press the sulfuric acid band solution on an acid paper or a neutral paper with a tab size press.
By using pseudo acid paper impregnated with a simsizer, air knife coater, blade coater, gate roll coater, bar coater, rod coater, roll coater, bill blade coater, short dwell blade coater, etc. An improved ink jet recording sheet can also be obtained. Paper (base paper) made from a slurry mainly composed of natural pulp
However, in the case of using so-called neutral paper mixed with heavy calcium carbonate or light calcium carbonate as an internal pigment (filler), the pH of the surface of the ink-jet recording sheet or the surface of the ink-receiving layer is changed with time. It gradually shifts to the alkaline region. This is because the pigment (filler) is a solid alkali, which affects the pH of the entire inkjet recording sheet. Therefore, it is a preferable embodiment to use acidic paper or pseudo acidic paper.

As the ink used for ink jet recording in the present invention, conventionally known inks can be suitably used, and dye (water-soluble) ink using dye as dye, dye (oil-soluble) ink, coloring material Can be broadly classified into four types: pigment (aqueous) ink using a pigment, and pigment (oil-based) ink.

Due to the problems of image vividness and the safety of the ink itself, the following dye (water-soluble) inks are often used. For example, CIDirect Yellow 12, CID
irect Yellow 24, CIDirect Yellow 26, CIDirect Ye
llow 44, CIDirect Yellow 86, CIDirect Yellow 98,
CIDirect Yellow 100, CIDirect Yellow 142, CIDi
rect red 1, CIDirect red 4, CIDirect red 17, CI
Direct red 28, CIDirect red 83, CIDirect Orenge
34, CIDirect Orenge 39, CIDirect Orenge 44, CID
irect Orenge 46, CIDirect Orenge 60, CIDirect Vi
olet 47, CIDirect Violet 48, CIDirect Blue 6, C.
I.Direct Blue 22, CIDirect Blue 25, CIDirect Blu
e 71, CIDirect Blue 86, CIDirect Blue 90, CIDir
ect Blue 106, CIDirect Blue 199, CIDirect Black
17, CIDirect Black 19, CIDirect Black 32, CIDir
ect Black 51, CIDirect Black 62, CIDirect Black
71, CIDirect Black 108, CIDirectBlack 146, CIDi
direct dyes such as rect Black 154, CIAcid Yellow 11,
CIAcid Yellow 17, CIAcid Yellow 23, CIAcid Yel
low 25, CIAcid Yellow 29, CIAcid Yellow 42, CIA
cid Yellow 49, CIAcid Yellow 61, CIAcid Yellow 7
1, CIAcid red 1, CIAcid red 6, CIAcid red 8, C.
I.Acid red 32, CIAcid red 37, CIAcid red 51, CI
Acid red 52, CIAcid red 80, CIAcid red 85, CIAc
id red 87, CIAcid red 92, CIAcid red 94, CIAcid
red 115, CIAcidred 180, CIAcid red 256, CIAcid
red 317, CIAcid red 315, CIAcid Orenge 7, CIAc
id Orenge 19, CIAcid Violet 49, CIAcid Blue 9, C.
I.Acid Blue22, CIAcid Blue 40, CIAcid Blue 59, C.I.
I.Acid Blue 93, CIAcid Blue 102, CIAcid Blue 10
4, CIAcid Blue 113, CIAcid Blue 117, CIAcid Blu
e 120, CIAcid Blue 167, CIAcid Blue 229, CIAcid
Blue 234, CIAcid Blue 254, CIAcid Black 2, CIA
cid Black 7, CIAcid Black 24, CIAcid Black 26, C.
I.Acid Black 31, CIAcid Black 52, CIAcid Black 6
3, acidic dyes such as CIAcid Black 112 and CIAcid Black 118, and other basic dyes, reactive dyes, and food colorants.

On the other hand, for example, JP-A-57-10660, JP-A-57-10661, and JP-A-4-2344.
Nos. 67, 5-156189, 5-179
Nos. 183, 5-202324, 5-26
Nos. 3029, 5-331313 and 6-1
Particularly suitable ink jet recording can be performed using a pigment (aqueous or oil-based) ink using a pigment as a coloring material as proposed in JP-A Nos. 22846 and 6-1363111. Here, as the pigment, for example, paranitroaniline red, toluidine red,
Azo pigments such as Fire Red, Naphthyramine Bordeaux, Orthonitroaniline Orange, Permanent Red G, Lake Fast Orange 3GL, Resor Red, Lake Red C, Lake Red D, Watching Red, Brilliant Carmine 6B, Bordeaux 10B, Maroon Light , Yellow GL, Orange G, Naphthol A
Poorly soluble azo pigments such as SITR, permanent red FR, permanent red FRLL, permanent red FGR, permanent red FBL, permanent red FRR, carmine BS, fast ero G, fast ero G, fast ero 3G, fast ero 5
G, Fast Yellow 10G, Fast Yellow GR, Benzine Yellow, Benzidine Yellow R, Benzidine Yellow GR, Benzidine Yellow G, Benzidine Yellow 5G and other insoluble azo pigments, copper phthalocyanine, chlorinated copper phthalocyanine, metal-free Phthalocyanine-based pigments such as phthalocyanine, synchasia red Y, synchasia red B,
Quinacridone pigments such as Synchasia Red R, dioxazine pigments such as trifendioisazine, carbazole diisazine violet, violet, anthrapyrimidine yellow, flavanthrone yellow, anthuanthrone scarred, indanthrone blue, isoveoran Vat dye pigments such as thulon violet, thioindigo bordeaux, thioindigo maroon, perinone orange, maroon, and scarlet, condensed azo pigments, isoindolinone pigments, carbon black, titanium oxide,
Examples include inorganic pigments such as zinc white, lead chromate pigments, and cadmium pigments.

Further, for example, JP-B-7-78187, JP-B-7-78188, JP-A-8-6057, JP-A-8-26259, JP-A-6-247034, JP-A-6-306319, etc. As coloring materials, for example, naphthol dyes, azo dyes, metal complex dyes, anthraquinone dyes, quinoimine dyes, indigo dyes, cyanine dyes, quinoline dyes, nitro dyes, nitroso dyes, benzoquinone dyes, carbonium dyes Ink jet recording can also be suitably performed using a dye (oil-soluble) ink using an oil-soluble dye such as a naphthoquinone dye, a naphthalimide dye, a phthalocyanine dye, or a perinine dye.

Specifically, examples of the oil-soluble dye include, for example,
CISolvent Yellow 1,2,3,4,6,7,8,10,12,13,14,16,1
8,19,21,25,25: 1,28,29,30,32,33,34,36,37,38,40,42,4
3,44,47,48,55,56,58,60,62,64,65,72,73,77,79,81,82,
83,83: 1,85,88,89,93,94,96,98,103,104,105,107,109,1
12,114,116,117,122,123,124,128,129,130,131,133,13
4,135,138,139,140,141,143,146,147,148,149,150,151,
152,153,157,158,159,160: 1,161,162,163,164,165,167,
168,169,170,171,172 etc .; CISolvent Red 1,2,3,4,
7,8,13,14,17,18,19,23,24,25,26,27,29,30,33,35,37,3
9,41,42,43,45,46,47,48,49,49: 1,52,68,69,72,73,74,8
0,81,82,83,83: 1,84,84: 1,89,90,90: 1,91,92,106,109,1
11,117,118,119,122,124,125,127,130,132,135,138,14
0,143,145,146,149,150,151,152,155,160,164,165,166,
168,169,172,175,176,177,179,180,181,182,185,188,18
9,195,198,202,203,204,205,206,207,208,209,210,212,
213,214,215,216,217,218,219,220,221,222,223,224,22
5,226,227,228,229 etc .; CISolvent Blue 2,4,5,7,1
0,11,12,22,25,26,35,36,37,38,43,44,45,48,49,50,51,
59,63,64,66,67,68,70,72,79,81,83,91,94,95,97,98,9
9,100,102,104,105,111,112,116,117,118,122,127,128,
129,130,131,132,133,134 etc .; CISolvent Black3,5,
6,7,8,13,22,22: 1,23,26,27,28,29,33,34,35,39,40,41,
42, 43, 45, 46, 47, 48, 49, 50 and the like.

Among these oil-soluble dyes, CISo
lvent Yellow 3,14,16,33,56, CISolvent Red 18,24,2
7,122,135, CISolvent Blue 14,25,35,48,108, CISol
ventBlack 3,7,22,34,50 has high dye fastness,
It can be suitably used.

The solvent used for the dye (oil-soluble) ink or pigment (oil-based) ink may be selected from the following so as to conform to the characteristics of the ink ejection head of the ink jet recording apparatus.
Alternatively, various solvents are selected from the viewpoint of safety, and in some cases, a mixture of plural kinds of solvents may be used.

Representative examples of such solvents are as follows: Pegazol (Mobil Petroleum), Shell S
Petroleum naphtha-based solvents such as BR and Shellsol (manufactured by Shell Petroleum); aromatic petroleum solvents such as Hysozol (manufactured by Nippon Petroleum);
Aliphatic petroleum solvents such as IP solvent (manufactured by Idemitsu Petrochemical); naphthenic petroleum solvents such as ink solvent (manufactured by Mitsubishi Petroleum); aromatics such as mono- or di-substituted alkylnaphthalene, alkyl derivatives of biphenyl, xylylethane, and phenethyl cumene Hydrocarbon solvent; methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-
C1-C4 alkyl alcohols such as butyl alcohol, tert-butyl alcohol and isobutyl alcohol; amides such as dimethylformamide and dimethylacetamide; ketones or ketone alcohols such as acetone and diacetone alcohol; tetrahydrofuran and dioxane Ethers; polyalkylene glycols such as polyethylene glycol and polypropylene glycol; ethylene glycol, propylene glycol, butylene glycol, triethylene glycol,
1,2,6-hexanetriol, thiodiglycol,
Alkylene glycols having 2 to 6 alkylene groups such as hexylene glycol and diethylene glycol; lower alkyl ethers of polyhydric alcohols such as glycerin, ethylene glycol methyl ether, diethylene glycol methyl (or ethyl) ether, and triethylene glycol monomethyl ether; Tributyl phosphate, tri-2-ethylhexyl phosphate, triphenyl phosphate,
Phosphates such as tricresyl phosphate; dimethyl phthalate, diethyl phthalate, dibutyl phthalate, diheptyl phthalate, di-n-octyl phthalate, di-2-ethylhexyl phthalate, diisononyl phthalate, octyl decyl phthalate Phthalic acid esters such as butylbenzyl phthalate; aliphatic monobasic acid esters such as butyl oleate and glycerin monooleate; dibutyl adipate, di-2-ethylhexyl adipate, alkyl adipate 610, azelaic acid Jee
Aliphatic dibasic acid esters such as 2-ethylhexyl, dibutyl sebacate and di-2-ethylhexyl sebacate; oxyacids such as methyl acetyl ricinoleate, butyl acetyl ricinoleate, butyl phthalyl butyl glycolate and acetyl tributyl citrate Esters: Plasticizers such as chlorinated paraffin, chlorinated biphenyl, 2-nitrobiphenyl, dinonylnaphthalene, o- and p-toluenesulfonethylamide, show brain, and methyl abietic acid.

Also, for example, inks for so-called hot-melt type ink jet recording proposed in Japanese Patent Publication Nos. 6-247034 and 6-306319 can be suitably used for ink jet recording. it can. The following solvents are generally used in hot-melt type inkjet recording inks.

For example, polyethylene wax, ozokerite, ceresin, candelilla wax, rice wax, jojoba solid wax, beeswax, lanolin, whale wax, Fischer-Tropsch wax, carnauba wax, paraffin wax, sasol wax, microcrystalline wax, ester wax Waxes and the like;
Diols such as 1,8-octanediol, 1,10-decanediol and 1,12-dodecanediol; fatty acids such as lauric acid, stearic acid and palmitic acid; lauric amide, stearic amide, oleic amide; Erucamide, ricinoleamide, 12
-Fatty acid amides such as hydroxystearic acid amide and special fatty acid amide; a general formula RCONHR 'or R
N-substituted fatty acid amides represented by NHCOR'CONHR;alkylolamides; higher alcohols such as cetyl alcohol and stearyl alcohol; aromatic compounds such as aromatic esters and aromatic alcohols; methyl laurate and methyl myristate , Methyl palmitate,
Monohydric alcohol fatty acid esters such as methyl stearate, palm fatty acid methyl, isopropyl myristate, butyl stearate, octadecyl stearate, oleyl oleate; glycerin fatty acid ester, sorbitan fatty acid ester, propylene glycol fatty acid ester, ethylene glycol fatty acid ester And polyhydric alcohol fatty acid esters such as polyoxyethylene fatty acid esters; epoxy resins; polyamide resins; polyester resins; polyacrylic resins; polyurethane resins;

In the various inks described above, for the purpose of improving the storage stability and the abrasion resistance after inkjet recording, for example, polyacrylic acid ester, linseed oil-modified alkyd resin, polystyrene, rosin resin,
Polar resins such as terpene phenolic resins and alkylphenol-modified xylene resins are added, sequestering agents,
Surface tension adjuster, surfactant, viscosity adjuster, defoamer, defoamer, release agent, foaming agent, penetrant, optical brightener, ultraviolet absorber, preservative, waterproofing agent, rheology modifier Further, additives such as an antioxidant can be appropriately contained.

[0101]

EXAMPLES The present invention will be described below with reference to examples of the present invention, but the present invention is not limited to these examples. Further, “parts” and “%” shown in the examples are parts by weight and% by weight unless otherwise specified.

The ink-jet recording sheets of the following examples and comparative examples were evaluated by the following methods.

(1) Blanking paper yellowing A plastic file bag (A4 size) made of polypropylene containing 1.0% by weight of BHT has a center of one side of 5 cm ×
Cut into 5 cm squares, put them in a file bag so that the surface of the ink receiving layer of each ink jet recording sheet is in contact with the perforated file surface, and 30 ° C., 80% R
H was left for 3 months in an environment. On the surface of the ink receiving layer after standing, the portion corresponding to the cut square of the plastic film turned yellow. The L * a * b * (CIE1976) before and after the treatment of the yellowing portion was measured with a color difference meter, CR-100 manufactured by Minolta. The degree of yellowing of the white paper can be represented by the difference between b * before and after the treatment (△ b *), and a smaller value indicates less yellowing.

(2) Image Density A black solid image was recorded on each ink jet recording sheet using a drop-on-demand type ink jet printer equipped with a dye ink, and Macbeth RD
At 919, the optical density was measured.

(3) Ink Absorbability A black thin line of 1 pixel (5 cm long) is recorded on each ink jet recording sheet at intervals of 2 pixels using a drop-on-demand type ink jet printer equipped with a dye ink, and the grid is printed. An eye-like evaluation pattern was created. This pattern was visually evaluated as follows. When the ink absorbency is poor, the edges of the fine lines are disturbed, and when the ink absorbency is poor, the blank portions of the grid are filled. ：: The fine line has a clean edge, and the grid is clearly visible. Δ: Disturbance is observed at the edge of the fine line, and the size of the grid is partially different. X: The edge of the fine line is largely disturbed, and blank portions of the grid are buried.

(4) Fixability of Pigment Ink A thin line of 1 pixel (5 cm long) is recorded on each ink jet recording sheet at intervals of 2 pixels using a drop-on-demand type ink jet printer equipped with a pigment ink. An eye-like evaluation pattern was created. Disturbance of the image after touching this pattern was visually evaluated as follows. If the fixability of the pigment ink is poor,
The pigment is scraped off and the edges of the fine lines are disturbed and bleed, and in severe cases, blank portions of the grid cannot be confirmed. ：: The fixation is good, the fine line has a clear edge, and the grid is clearly visible. Δ: The edge of the thin line was disturbed and blurred, and a blank portion of the grid could not be partially confirmed. X: The edge of the fine line was largely disturbed due to poor fixing, and almost no blank portion of the grid was observed.

(5) Water resistance of image A thin line of 1 pixel (5 cm length) is recorded on each ink jet recording sheet at intervals of 2 pixels using a drop-on-demand type ink jet printer equipped with a dye ink. An eye-like evaluation pattern was created. On this pattern, 10 ml of tap water was dropped and left for 12 hours. Regarding the evaluation pattern after standing, the degree of bleeding of the fine line was visually evaluated as follows. A: There is no bleeding. ：: Although very slight bleeding is observed, the thin line has a clear edge, and the cross-cut is clearly visible. Δ: The edge of the thin line was slightly disturbed and blurred, and a blank portion of the grid was not able to be confirmed partially. ×: The bleeding of the edge of the fine line is large, and a blank portion of the grid cannot be confirmed.

A method for producing porous starch particles in which various fine particles are embedded will be described below. (Porous Starch Particles A) 100 parts of porous starch particles (porous starch: porous starch particles produced by reacting a raw starch-degrading enzyme on corn starch particles, porosity 50-60%, manufactured by Sanei Saccharification) And heavy calcium carbonate (NS600, particle size 1.5 μm, manufactured by Nitto Powder Chemical Co., Ltd.) 30 having an oil absorption of 30 ml / 100 g specified in JIS-K5101
The mixture was filled in a paint shaker and mixed for 3 hours. After mixing, the mixture was gently passed through a mesh to separate heavy calcium carbonate that was not embedded and porous starch particles in which the heavy calcium carbonate was embedded. The porous starch particles in which heavy calcium carbonate is embedded are sprayed from the upper part of a spray dryer equipped with a coating nozzle, while a 5% aqueous solution of polyvinyl alcohol (PVA117, polymerization degree 1700, manufactured by Kuraray) is sprayed from the coating nozzle. It was sprayed and dried and finely divided to obtain porous starch particles A in which heavy calcium carbonate was embedded and bound. When the porous starch particles A were observed with a scanning electron microscope, fine particles of heavy calcium carbonate filled and buried in the holes opened in the porous starch particles could be seen. Moreover, the embedding rate (%) of heavy calcium carbonate was calculated using the following mathematical formula 1, and it was 30.5%.

[0109]

Embedded image embedded ratio (%) = 100 × (γ−α) / (β−α) where α = A ′ / A, β = B ′ / B and γ = C ′ /
C. A: Absolute dry weight (g) when porous starch particles before embedding treatment were dried at 105 ° C. for 1 hour A ′: Ash content when baking porous starch particles before embedding treatment at 500 ° C. for 1 hour ( g) B: Absolute dry weight when the embedded fine particles are dried at 105 ° C. for 1 hour (g) B ′: Ash content when the embedded fine particles are baked at 500 ° C. for 1 hour (g) C: Burial treatment Absolute dry weight (g) when the subsequent porous starch particles A were dried at 105 ° C. for 1 hour C ′: Ash content (g) when baking the porous starch particles A after embedding at 500 ° C. for 1 hour

(Porous Starch Particles B) The heavy calcium carbonate of the porous starch particles A was converted into calcined kaolin (HYC) having an oil absorption of 80 ml / 100 g specified in JIS-K5101.
AL, particle size 0.7 μm, manufactured by Nissei Kyoei), except that porous starch particles A were prepared. The burial rate was 32.5%.

(Porous Starch Particles C) The heavy calcium carbonate of the porous starch particles A was replaced with light calcium carbonate (Tamapearl TP123, particle size 0.8 μm, Okutama having an oil absorption of 135 ml / 100 g specified in JIS-K5101). Porous starch particles C were prepared in the same manner as the porous starch particles A except that the amount was changed to 40 parts (manufactured by Kogyo). Burial rate is 35.9%
Met.

(Porous Starch Particles D) The heavy calcium carbonate of the porous starch particles A was converted to silica particles (fine seal X37B, particle size 2.6 μm, Tokuyama having an oil absorption of 260 ml / 100 g, specified in JIS-K5101). Made) 40
The procedure was the same as that for the porous starch particles A except that the parts were changed to parts. The burial rate was 22.1%.

(Porous Starch Particles E) The heavy calcium carbonate of the porous starch particles A was mixed with alumina fine particles having an oil absorption of 100 ml or more / 100 g (AS-3: 10% aqueous dispersion as specified in JIS-K5101). Porous starch particles E were obtained in the same manner as the porous starch particles A, except that the powder was changed to 40 parts by pulverization by a spray-dry method and a particle size of 1.0 μm, manufactured by Catalyst Chemicals Co., Ltd. The burial rate was 37.1%.

(Porous Starch Particles F) The heavy calcium carbonate of the porous starch particles A was replaced with calcium carbonate (FA) having an oil absorption of 25 ml / 100 g specified in JIS-K5101.
Porous starch particles F were obtained in the same manner as the porous starch particles A, except that XE82 was changed to a particle size of 2.3 μm (manufactured by Nissei Kyoei). The burial rate was 33.4%.

Hereinafter, Examples and Comparative Examples relating to the first ink jet recording sheet of the present invention will be described. Example 1 80 parts of LBKP (freeness 400 mlcsf) and NBKP
(Freeness: 480 mlcsf) 20 parts of wood pulp composed of 20 parts, 20 parts of porous starch particles A, 0.10 part of commercially available alkyl ketene dimer, 0.03 part of commercially available cationic acrylamide, and 1.0 part of commercially available cationized starch And 0.5 part of a sulfuric acid band, and then sheet-formed with a sheet former. Further calendered, basis weight 100 g / m
^2. An ink jet recording sheet of Example 1 having a thickness of 115 μm was obtained.

Examples 2 to 6 Porous starch particles A were prepared in the same manner as in Example 1 except that the porous starch particles A were changed to porous starch particles B to F, respectively. Obtained.

Comparative Example 1 An ink jet recording sheet of Comparative Example 1 was obtained in the same manner as in Example 1 except that the slurry was not added and the paper was made by mixing the slurry.

Comparative Example 2 Porous starch particles A were prepared by using porous starch particles having no fine particles embedded therein (porous starch: corn starch particles produced by reacting a raw starch-degrading enzyme with porous starch particles, voids). The production was performed in the same manner as in Example 1 except that the ratio was changed to 50 to 60% (manufactured by Sunei Saccharification Co., Ltd.), and an ink jet recording sheet of Comparative Example 2 was obtained.

Comparative Example 3 The same procedure as in Example 1 was carried out except that the porous starch particles A were changed to starch particles having no pores (corn starch particles, manufactured by Sanwa Starch Kogyo Co., Ltd.). A recording sheet was obtained.

Comparative Example 4 80 parts of LBKP (freeness 400 mlcsf) and NBKP
(Freeness: 480 mlcsf) Pigment having a synthetic amorphous silica (fine seal X37B, manufactured by Tokuyama) / light calcium carbonate / heavy calcium carbonate in a ratio of 2/1/1 to 100 parts of wood pulp consisting of 20 parts. 25 parts, commercially available alkyl ketene dimer 0.10 part, commercially available cationic acrylamide 0.03 part, commercially available cationized starch 1.0 part,
After preparing 0.5 part of a sulfuric acid band, it was paper-formed with a sheet former. Further, it is subjected to a calendering treatment to obtain a basis weight of 100 g /
An ink jet recording sheet of Comparative Example 4 having an m ² and a thickness of 120 μm was obtained.

Comparative Example 5 80 parts of LBKP (freeness 400 mlcsf) and NBKP
(Freeness: 480 ml csf) Alumina fine particles (AKPG015,
25 parts of a pigment having a ratio of 2/1 (Sumitomo Chemical Co., Ltd.) / Talc, 3 parts of a sulfuric acid band, 0.2 parts of a commercially available rosin sizing agent, and 0.3 parts of a commercially available cationized starch were prepared and then sheeted using a sheet former. Further, it is subjected to a calendering treatment to obtain a basis weight of 100 g /
An inkjet recording sheet of Comparative Example 5 having an m ² and a thickness of 120 μm was obtained.

The results of evaluation of the first ink jet recording sheet of the present invention shown in Examples 1 to 6 and Comparative Examples 1 to 5 are shown in Table 1.

[0123]

[Table 1]

(Evaluation) For the first ink jet recording sheet of the present invention shown in Examples 1 to 6, as shown in Table 1,
The yellowing of the white paper, the fixability of the pigment ink, and the water resistance of the image were able to be improved while maintaining the image density and the ink absorbency at the same levels as Comparative Examples 4 and 5. In particular, in Examples other than Example 6, since the fine particles embedded in the pores of the porous starch particles were fine particles having an oil absorption of 30 ml / 100 g or more, fine silica particles or fine alumina particles, the image density and water resistance of the images were low. The properties became even better.

On the other hand, in Comparative Example 1 or Comparative Example 3, ordinary starch particles which did not contain porous starch particles in which fine particles were embedded or did not have pores were used.
All of the characteristics such as image density, ink absorbency, fixability of pigment ink and water resistance of the image were inferior. Comparative Example 2 contained only porous starch particles without embedded fine particles.
In particular, the water resistance of the image could not be satisfactorily improved. In Comparative Examples 4 and 5, since the ink jet recording sheet was formed by directly adding silica fine particles or alumina fine particles to the slurry, the yellowing of the white paper was not improved at all, and the water resistance and the like were poor.

Hereinafter, Examples and Comparative Examples relating to the second ink jet recording sheet of the present invention will be described.

Example 7 90 parts of LBKP (freeness: 380 mlcsf) and NBKP
(Freeness: 480 mlcsf) 20 parts of a pigment having a ratio of light calcium carbonate / heavy calcium carbonate of 1: 1 to 100 parts of wood pulp consisting of 10 parts, 10 parts of commercially available alkyl ketene dimer, and commercially available cationic acrylamide After preparing 0.03 part, commercially available cationized starch 1.0 part, and sulfuric acid band 0.5 part, it is paper-made with a fourdrinier paper machine, and has a basis weight of 120 g.
/ M ² neutral paper was obtained.

On this neutral paper, an ink receiving layer coating liquid having the following composition was applied by a rod bar so as to have a dry coating amount of 11 g / m ² , dried, and then subjected to a calendering treatment. An ink jet recording sheet was obtained. <Ink receiving layer coating liquid formulation> Porous starch particles A 100 parts PVA (PVA117, Kuraray, 10% aqueous solution) 50 parts Water 270 parts

Examples 8 to 12 The same procedures as in Example 7 were carried out except that the porous starch particles A in the ink receiving layer were changed to porous starch particles BF, respectively. Was obtained.

Comparative Example 6 Porous starch particles A were prepared by mixing porous starch particles without embedded fine particles (porous starch: porous starch particles produced by reacting raw starch-degrading enzyme on corn starch particles, voids). The production was performed in the same manner as in Example 7, except that the ratio was changed to 50 to 60% (manufactured by Sunei Saccharification Co., Ltd.). Thus, an ink jet recording sheet of Comparative Example 6 was obtained.

Comparative Example 7 The same procedure as in Example 7 was carried out except that the porous starch particles A were changed to starch particles having no pores (corn starch particles, manufactured by Sanwa Starch Kogyo Co., Ltd.). A recording sheet was obtained.

Comparative Example 8 An ink jet recording sheet of Comparative Example 8 was obtained in the same manner as in Example 7, except that the ink receiving layer was changed to the following composition. <Ink receiving layer coating liquid formulation> Synthetic amorphous silica (Fine Seal X37B, manufactured by Tokuyama) 100 parts PVA (PVA117, Kuraray, 10% aqueous solution) 300 parts Water 320 parts

Comparative Example 9 An ink jet recording sheet of Comparative Example 9 was obtained in the same manner as in Example 7, except that the ink receiving layer was changed to the following composition. <Ink receiving layer coating liquid composition> Alumina powder (AKPG015, manufactured by Sumitomo Chemical) 100 parts PVA (PVA117, Kuraray, 10% aqueous solution) 250 parts Water 380 parts

As described above, Examples 7 to 12 and Comparative Examples 6 to 9
Table 2 summarizes the evaluation results of the second ink jet recording sheet of the present invention shown in FIG.

[0135]

[Table 2]

(Evaluation) For the second ink jet recording sheet of the present invention shown in Examples 7 to 12, as shown in Table 2,
The yellowing of the white paper, the fixability of the pigment ink, and the water resistance of the image were able to be improved while maintaining the image density and the ink absorbency at the same level as Comparative Examples 8 and 9. In particular, in Examples other than Example 12, since the fine particles embedded in the pores of the porous starch particles had an oil absorption of 30 ml / 100 g or more, or were silica fine particles or alumina fine particles, the image density and the water resistance of the image were low. Has become even better.

On the other hand, in Comparative Example 6, since only the porous starch particles having no fine particles embedded therein were contained, the water resistance of the image in particular could not be improved sufficiently. Comparative Example 7
Then, because normal starch particles without pores were used,
All of the characteristics such as image density, ink absorbency, fixability of pigment ink and water resistance of the image were inferior. In Comparative Examples 8 and 9,
Since the ink jet recording sheet contained silica fine particles or alumina fine particles as they were in the ink receiving layer, the yellowing of the white paper was not improved at all and the water resistance was poor.

[0138]

In the ink jet recording system, devices such as printers and plotters have been improved, and high-definition and high-quality images can be output at low cost. In the future, it is expected that the ink-jet recording sheet will be widely used as an alternative method for silver halide photography, and stable long-term storage properties of the ink-jet recording sheet and ink-jet recording suitability using a pigment ink will be extremely important. According to the present invention, yellowing of white paper, fixability of pigment ink, and water resistance of an image can be improved.

Claims (6)

[Claims] 1. An ink jet recording sheet obtained by paper-making a slurry containing natural or synthetic fibers as a main component, wherein said sheet contains porous starch particles having fine inorganic or organic particles embedded in pores. An ink jet recording sheet, characterized in that: 2. The ink jet recording sheet according to claim 1, wherein the fine particles have an oil absorption of 30 ml / 100 g or more specified in JIS-K5101. 3. The ink jet recording sheet according to claim 1, wherein the fine particles are at least one kind of fine particles of silica or alumina. 4. An ink jet recording sheet comprising an ink receiving layer provided on at least one side of a support, wherein the ink receiving layer comprises porous starch particles having inorganic or organic fine particles embedded mainly in pores. An ink jet recording sheet comprising a binder resin. 5. The ink jet recording sheet according to claim 4, wherein the fine particles have an oil absorption of 30 ml / 100 g or more specified in JIS-K5101. 6. The ink jet recording sheet according to claim 4, wherein the fine particles are at least one kind of fine particles of silica or alumina.