JPH11334199A - Inkjet recording sheet - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To harden a hard copy obtained by ink jet recording in a file and store it, or to adhere to an ink-receiving layer with an adhesive tape to yellowish white paper or pigment ink. To obtain an ink jet recording sheet having improved fixability. A non-coating type ink jet recording sheet obtained by making a slurry containing natural or synthetic fibers as a main component is made to contain porous starch particles in the sheet. Further, in a coating type ink jet recording sheet provided with an ink receiving layer on at least one surface of a support, the ink receiving layer contains porous starch particles.

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 good ink absorbency, particularly improved yellowing of white paper, and excellent fixability of pigment ink. It is a recording sheet.

[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 salt 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 closed and stored in a file or when an adhesive tape is adhered to the surface of an 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 BET, 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 particular, in order to pursue image density and color development, simply using synthetic amorphous silica having a large specific surface area,
When the colloidal particles of alumina hydrate having a pseudo-boehmite structure were used, the yellowing of the white paper was particularly deteriorated.

The yellowing of the white paper of such an ink jet recording sheet is caused, for example, when the recording sheet is inserted into a clear file containing BHT and stored, the BHT is transferred from the clear file to the ink receiving layer of the recording sheet. It can be guessed that it will occur after migration. Therefore, when a familiar article containing a phenolic antioxidant represented by BHT comes into contact with an ink jet recording sheet, yellowing proceeds, and secondary factors such as ozone, NO _x , SO _x and temperature and humidity in the air. It is thought that it will be further promoted by

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. In the proposal, in an ink jet recording sheet, [4,4′-methylene-bis-2,6- (di-tert-butylphenol)] (hereinafter referred to as B
A method of evaluating the catalytic activity of the porous ink receiving layer when the dye in the ink is decomposed by oxygen by a spot test performed using HT ₂ ) is described. This BHT ₂ spot test is based on the fact that BHT is oxidized and colored yellow when a stilbenequinone structure is formed, and the correlation between the results of the test and indoor discoloration of a printed image on an ink jet recording material is found. I have.

Further, in the proposal, as a preferred coat layer, that is, a form of the ink receiving layer, which has little yellowing in the BHT ₂ spot test, a metal selected from the group consisting of Mg, Ca, Zn, and Ba is used in an amount of 0.1% by weight. % Of the silicon-containing pigment in the recording surface, that is, in the ink receiving layer, but is described as having a side effect of reducing 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 a hard copy obtained by ink-jet recording, for example, by storing the hard copy in a file, for example, or by attaching an adhesive tape to an ink-receiving layer. An object of the present invention is to provide a high-quality ink jet recording sheet in which yellowing is improved and the fixability of the pigment ink is excellent.

[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 closed and stored in a file. Or the yellowing of white paper, which occurs when an adhesive tape is adhered to the ink receiving layer, is caused by the occurrence of 2,6-di-tert-butyl-4-methyl-phenol (hereinafter referred to as "file") contained in the file or the adhesive tape. , BHT) was estimated to be due to a phenolic antioxidant.

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-t-butyl-4'-hydroxyphenyl) propionate (Irganox 1076: Ciba-Geigy, Adekastab AO-50: Asahi Denka, Sumilizer BP-76: Sumitomo Chemical, Tominox SS: Yoshitomi Pharmaceutical) ), 4,4'-butylidenebis- (3-methyl-6
-T-butylphenol) (ADK STAB AO-40:
Asahi Denka, Sumilizer BBM-S: Sumitomo Chemical, Yoshinox BB: Yoshitomi Pharmaceutical, Antage W300: Kawaguchi Chemical,
Knock riser NS30: Emerging Ouchi, non-flex B
B: Seiko Chemical Co., Ltd.).

The inventors of the present invention have further studied the method for improving the yellowing of white paper caused by the phenolic antioxidant as described above. As a result, the conventionally known pigments and colloid particles constituting the ink receiving layer were porous. It has been found that the yellowing of white paper can be improved without impairing the ink jet recording characteristics such as image density and ink absorbability by changing to the basic starch particles.

Further, it has been found that the 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. 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, magnesium hydroxide, etc. In many cases, the pigment (filler) represented by
By replacing all or part of these pigments with porous starch particles, the yellowing of white paper could be improved.

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. In general, when the pigment having a particle size of about 0.05 to 0.5 μm flies and lands on the recording sheet surface, many pigments do not penetrate into the sheet and accumulate on the surface. Met.

According to the present inventors' earnest studies, such a problem could be improved by using porous starch particles. The porous starch particles are larger than conventionally known pigments and colloidal particles, and have appropriate pores, so that the pigment can be quickly penetrated, and as a result, the fixability of the pigment ink can be improved. .

That is, the first ink jet recording sheet of the present invention is a non-coating type ink jet recording sheet obtained by making a slurry containing natural or synthetic fibers as a main component, wherein the sheet contains porous starch particles. Is an ink jet recording sheet characterized by containing.

Further, the surface pH of the first ink jet recording sheet of the present invention specified in TAPPI T529
Is 6.0 or less, the yellowing of white paper can be further improved.

When a paper made from a slurry containing natural pulp as a main component is used as the ink jet recording sheet, the paper is made acidic paper to obtain an ink jet recording sheet in which the yellowing of white paper is further improved. be able to.

In the case where a neutral paper made from a slurry containing natural pulp as a main component is used as the ink jet recording sheet, pseudo-acid paper in which a sulfuric acid band solution is permeated on the neutral paper is further used. A preferable ink jet recording sheet can be obtained.

The second ink jet recording sheet of the present invention is a coating type ink jet recording sheet comprising an ink receiving layer provided on at least one surface of a support.
An ink jet recording sheet for ink, wherein the ink receiving layer contains porous starch particles.

Further, when the surface pH defined by TAPPI T529 of the ink receiving layer of the second ink jet recording sheet of the present invention is 6.0 or less, the yellowing of white paper can be further improved.

In the case where a paper made from a slurry containing natural pulp as a main component is used as the support, the paper is made into an acidic paper, whereby an ink jet recording sheet in which the yellowing of white paper is further improved can be obtained. Obtainable.

Alternatively, in the case where neutral paper made from a slurry containing natural pulp as a main component is used as the support, pseudo-acid paper in which a sulfuric acid band solution is impregnated on the neutral paper is further used. A preferable ink jet recording sheet can be obtained.

[0033]

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 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.

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 isolated 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. 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,
Water 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 the temperature and the treatment time of the enzyme reaction.
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, when the porosity is less than 30%, the image density and the ink absorbency are unfavorably reduced, and the fixability of the pigment ink may be deteriorated. On the other hand, when the porosity exceeds 80%, the mechanical strength of the porous starch particles is remarkably reduced, so that the porous starch particles are mixed and dispersed with various materials as a coating liquid for the ink receiving layer, and various kinds of calendering treatments described below are performed. In the step, the particles are easily 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.

The porous starch particles may contain fine synthetic amorphous silica particles having an average particle diameter of, for example, about 0.1 to 3 μm in the pores within a range that does not adversely affect the effects of the present invention. And alumina 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 sol, 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 / isoprene resin, methyl methacrylate / butyl methacrylate resin, polycarbonate resin, silicone resin, urea resin, melamine resin, epoxy Polymer beads such as resin, phenolic resin and diallyl phthalate resin can also be embedded. For example, by embedding minute alumina particles in the pores of the porous starch particles, it is possible to obtain an ink jet recording sheet with improved color and color development. In addition, by embedding polymer beads or the like having high lipophilicity or oil swelling property, particularly in ink jet recording using an oil-soluble ink, an ink jet recording sheet with improved image bleeding and image strikethrough can be obtained. It is possible to obtain. The embedding method includes, for example, a method of mechanically mixing the porous starch particles and the particles to be embedded with a paint conditioner, a ball mill, or the like.

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. The porous starch particles are contained in the slurry in which is dispersed, and obtained by making a paper using various devices such as a fourdrinier paper machine, a circular net paper machine, a twin wire paper machine, or on the surface of a sheet that has already been made. The target inkjet recording sheet can be obtained by infiltrating the porous starch particles using a size press method such as a calendar size or a tab size.

The content of porous starch particles 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. 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 also be used in combination.

The first ink jet recording sheet of the present invention can be subjected to calendar processing such as machine calender, super calender, gloss calender, mat calender, friction calender and brush calender. 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. . In the ink receiving layer, a binder resin is preferably contained in addition to the porous starch particles 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. Here, when the content of the binder resin is less than 0.1% by weight, the adhesive force between the porous starch particles or between the particles and the support is weak, and adverse effects such as falling off of the particles are likely to occur. If it exceeds 100% by weight, the pores of the porous starch particles are buried in the binder resin, and adverse effects such as a decrease in image density and ink absorbency are likely to occur.

Examples of the binder resin which can be preferably used include, for example, polyvinyl alcohol, silanol-modified polyvinyl alcohol, polyvinyl acetate, oxidized starch, etherified starch, cellulose derivatives such as carboxymethylcellulose, hydroxyethylcellulose, 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.

The ink jet recording sheet has a high image density, a bright and vivid color tone, a quick ink absorption, and prevents the ink from flowing or bleeding even when the dots are overlapped. 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. Although it can be generally achieved by using particles, in some cases, a more preferable ink jet recording sheet can be obtained by including a pigment, a colloid particle, or a mixture thereof together with the porous starch particles.

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.

According to the results of intensive studies by the present inventors,
Among the above-mentioned pigments, it is preferable to use synthetic amorphous silica in combination with porous starch particles from the viewpoint of color and color reproducibility.

Here, synthetic amorphous silica refers to an electric arc method,
It can be manufactured by a method such as a dry method or a wet method (precipitation method, gel method), and has a particle size of 0.1 to 30 μm by a Coulter counter method and a specific surface area of 2 by a BET method.
0 m ² / g or more, more preferably 50 to 400 m ² / g, and the oil absorption is 0.3 ml / g or more, more preferably 1.0 ml / g.
g or more, and Hunter whiteness of 90 or more are preferable. Specific examples of such synthetic amorphous silica 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)

4) Measured by Coulter counter method
It has a median diameter of １５15 μm, an oil absorption of 180 ml / 100 g, a refractive index of 1.450 or more as measured by a solvent method, and a water absorption of 35 under the conditions of 90% relative humidity and 200 hours of moisture absorption at 25 ° C. % Amorphous silica (JP-A-62-292476)

5) Measured by Coulter counter method
It has a median diameter of １５15 μm, an oil absorption of 180 ml / 100 g, a refractive index of 1.450 or more as measured by a solvent method, and a water absorption of 35 under the conditions of 90% relative humidity and 200 hours of moisture absorption at 25 ° C. % Of the amorphous silica particles in the range of 0.5% to 20% by weight based on the oxide based on the oxide of the Group 2 metal compound of the periodic table (Japanese Patent Laid-Open No. 63-306074). Gazette)

6) The specific surface area measured by the BET method is 200
m ² / g or more and the uniform number n of the rosin-Rammler distribution is 1.1
Zero or more fine silica (Japanese Patent Publication No. 3-26665)

7) When the BET specific surface area is 200 m ² / g or more,
Oil absorption of 180ml / 100g or more and acid strength (H0) +
Alkali-doped amorphous silica having an acid content up to 4.8 of 0.1 mmol / g or less (JP-A-5-64953)
And the like.

On the other hand, as the colloidal particles, for example, alumina hydrate (pseudo boehmite sol) and JP-A-60-21
Nos. 9083, 61-19389, 61-
Colloidal silica as described in JP-A-188183, JP-A-63-178074, JP-A-5-51470, and the like, described in JP-B-4-19037, and JP-A-62-286787. Such as silica / alumina hybrid sol, smectite clay such as hectite and montmorillonite (JP-A-7-81210), zirconia sol, chromia sol, yttria sol, ceria sol, iron oxide sol, zircon sol, antimony oxide sol and the like. It can be mentioned as a typical thing.

According to the results of intensive studies by the present inventors,
Among the colloidal particles as described above, it is preferable to use alumina hydrate (pseudo boehmite sol) in combination from the viewpoint of color and color reproducibility. Here, the pseudo-boehmite sol is an alumina hydrate that can be represented by a composition formula of Al ₂ O ₃ .nH ₂ 0 (n = 1 to 1.5), and USP
2,656,321, a synthesis method as described in JP-A-4-92,913, a hydrolysis method of aluminum alkoxide, a hydrolysis method of sodium aluminate, and a pH swing method. These are colloidal particles having a cilia-like or plate-like shape. More specifically,

1) 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 that has been hydrophilized and dried, the particle shape has 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 with 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 hydrophilic collodion film 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. 4-92913)

4) An aqueous solution consisting 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 for 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) A cation other than a hydrogen ion is contained in a range of 2.0 × 10 ^{-4 to} 1.0 × 10 ^-1 N in the sum of specified 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 spacing between the (020) planes 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 (Japanese Patent Laid-Open No. 7-232473)
And the like.

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 pigment dispersant, a thickener, a flow improver, and an antifoaming agent , Foam inhibitor, release agent, foaming agent, penetrant,
Coloring dyes, coloring pigments, fluorescent brighteners, ultraviolet absorbers, preservatives, antibacterial agents, waterproofing 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 . If the coating amount is less than 1 g / m ^2, it is not preferable because sufficient image density and ink absorbency cannot be obtained, and if the coating amount is more than 50 g / m ² , the curl property of the inkjet recording sheet is deteriorated. 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 flat pigment or hydrohaloysite. Even when a back coat is not provided, curling can be forced 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 recording sheet and ink receiving layer is 6.0 or less, yellowing of blank paper is further suppressed. Is done. 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, the ink receiving layer is made of hydrochloric acid, nitric acid, sulfuric acid, acetic acid,
It is also preferable to lower the pH using an acidic substance such as 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 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 6-136311. 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, Benzidine 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, isoveolane Vat dye pigments such as thulon violet, thioindigo bordeaux, thioindigo maroon, perinone orange, maroon, scarlet, etc., condensed azo pigments, isoindolinone pigments and 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 in the dye (oil-soluble) ink or the pigment (oil-based) ink is selected from the group consisting of:
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 Oil), Solutol (manufactured by Philips Petroleum), Exsol (manufactured by Exxon Chemical), Isopar (manufactured by Exxon),
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 in the environment for 4 months. 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 pigment ink, and Macbeth RD
At 919, the optical density was measured.

(3) Ink Absorbability A black thin line (5 cm long) of one pixel is image-recorded on each ink jet recording sheet at intervals of two pixels using a drop-on-demand type ink jet printer equipped with a pigment ink. 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.

Examples and comparative examples of the first ink jet recording sheet of the present invention will be described below.

Example 1 80 parts of LBKP (freeness 400 mlcsf) and NBKP
(Freeness: 480 ml csf) Porous starch particles (porous starch: porous starch particles produced by treating raw corn starch particles with a raw starch-degrading enzyme, per 100 parts of wood pulp consisting of 20 parts, porosity) 45%, Sanei Saccharification) 20 parts, commercially available alkyl ketene dimer 0.10 part,
After preparing 0.03 part of a commercially available cationic acrylamide, 1.0 part of a commercially available cationized starch, and 0.5 part of a sulfuric acid band, a sheet was formed using a sheet former. Further, a calendering treatment was performed to obtain a non-coated type ink jet recording sheet of Example 1 having a basis weight of 100 g / m ² and a thickness of 115 μm. After conditioning the recording sheet at 20 ° C. and 65% RH for 3 days, TAPP
The surface pH measured according to IT529 was 6.5.

Example 2 80 parts of LBKP (freeness 400 mlcsf) and NBKP
(Freeness: 480 ml csf) Porous starch particles (porous starch: porous starch particles produced by treating raw corn starch particles with a raw starch-degrading enzyme, per 100 parts of wood pulp consisting of 20 parts, porosity) 45%, manufactured by Sunei Saccharification Co., Ltd.) 20 parts, pigment having a ratio of light calcium carbonate / heavy calcium carbonate of 1/1, 10 parts of commercial alkyl ketene dimer, 0.10 part of commercial cationic acrylamide 0.0
3 parts, commercial cationized starch 1.0 part, sulfate band 0.5
After preparing the part, the sheet was formed by a sheet former. Further calendered, basis weight 100 g / m ² , thickness 120 μm
Of Example 2 was obtained.

Example 3 80 parts of LBKP (freeness 400 mlcsf) and NBKP
(Freeness: 480 ml csf) Porous starch particles (porous starch: porous starch particles produced by treating raw corn starch particles with a raw starch-degrading enzyme, per 100 parts of wood pulp consisting of 20 parts, porosity) After preparing 20 parts of 45%, manufactured by Sanei Saccharification Co., Ltd., 10 parts of talc, 3 parts of sulfate band, 0.2 parts of a commercially available rosin sizing agent, and 0.3 parts of a commercially available cationized starch, they were sheeted using a sheet former. Further, a calendering treatment was performed to obtain an uncoated type ink jet recording sheet of Example 3 having a basis weight of 100 g / m ² and a thickness of 120 μm.
This recording sheet is an acidic paper using a large amount of a sulfuric acid band using talc.

Example 4 A 10% aqueous solution of a sulfuric acid band was applied to the front and back surfaces of the uncoated type ink jet recording sheet prepared in Example 2 using a one-step processor so that the dry coating amount was 1 g / m ^2. After drying, an uncoated inkjet recording sheet of Example 4 was obtained. This recording sheet neutralizes the alkali of light calcium carbonate / heavy calcium carbonate by applying a sulfuric acid band, and can be regarded as a pseudo acidic paper.

Comparative Example 1 80 parts of LBKP (freeness 400 mlcsf) and NBKP
(Freeness: 480 mlcsf) 25 parts of pigment having a ratio of light calcium carbonate / heavy calcium carbonate of 1/1 to 100 parts of wood pulp composed of 20 parts, 25 parts of commercially available alkyl ketene dimer, 0.10 parts of commercially available cationic acrylamide After preparing 0.03 part, 1.0 part of commercially available cationized starch, and 0.5 part of a sulfate band, the sheet was formed using a sheet former. Further, it is subjected to a calendering treatment to obtain a basis weight of 100 g / m ² and a thickness of 12 g.
A non-coated ink jet recording sheet of Comparative Example 1 having a thickness of 0 μm was obtained.

Comparative Example 2 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 calendered, basis weight 100g /
An uncoated ink jet recording sheet of Comparative Example 2 having an m ² and a thickness of 120 μm was obtained.

Comparative Example 3 80 parts of LBKP (freeness 400 mlcsf) and NBKP
(Freeness: 480 mlcsf) 25 parts of pigment having a ratio of alumina particles (AKPG015, manufactured by Sumitomo Chemical) / talc of 2/1 to 100 parts of wood pulp consisting of 20 parts, 25 parts of sulfuric acid band, 3 parts of sulfuric acid band, commercial rosin sizing agent 0 After preparing 2 parts and 0.3 parts of a commercially available cationized starch, it was paper-formed with a sheet former. Further calendered, basis weight 100 g / m ² ,
An uncoated ink jet recording sheet of Comparative Example 3 having a thickness of 120 μm was obtained.

Comparative Example 4 The procedure of Comparative Example 4 was repeated except that the porous starch particles were replaced by starch particles having no pores (corn starch particles, manufactured by Sanwa Starch Kogyo Co., Ltd.). An uncoated ink jet recording sheet was obtained.

The evaluation results of the first ink jet recording sheet of the present invention shown in Examples 1 to 4 and Comparative Examples 1 to 4 are summarized in Table 1.

[0117]

[Table 1]

(Evaluation) In the case of the ink jet recording sheet of the present invention shown in Examples 1 to 4, as shown in Table 1, while maintaining the image density and the ink absorbency at the same level as Comparative Examples 2 and 3, And the fixability of the pigment ink could be improved. Particularly, in Examples 3 and 4, since the surface pH of the ink receiving layer was 6.0 or less, the yellowing of the white paper could be further suppressed.

On the other hand, Comparative Examples 1 to 3 were uncoated ink jet recording sheets containing conventionally known light calcium carbonate, heavy calcium carbonate, synthetic amorphous silica or alumina particles. The yellowing was remarkable, and the fixability of the pigment ink was poor. Comparative Example 4
Has low image density due to the use of ordinary starch particles having no pores, and is inferior in ink absorbency and pigment ink fixability.

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

Example 5 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, papermaking was carried out with a fourdrinier paper machine, and the basis weight was 120 g /.
to obtain a neutral paper m ^2.

On this neutral paper, a coating solution (pH: 6.5) of the ink receiving layer having the following composition was applied using a rod bar so that the dry coating amount was 11 g / m ^2, and the coating was dried. To obtain a coated paper type ink jet recording sheet of Example 5. The recording sheet was heated at 20 ° C. and 65% RH.
, And the surface pH of the ink receiving layer defined by TAPPI T529 was measured and found to be 7.0. An electron micrograph of the surface of the ink receiving layer of the recording sheet is shown in FIG. In the figure, one white line is 100 μm
Is equivalent to <Formulation of coating liquid for ink receiving layer> 100 parts of porous starch particles (porous starch: porous starch particles produced by reacting corn starch particles with raw starch-degrading enzyme, porosity 45%, manufactured by Sanei Saccharification) PVA (PVA117, 10% aqueous solution made by Kuraray) 50 parts Water 270 parts

Example 6 A coating type ink jet recording sheet of Example 6 was obtained in the same manner as in Example 5, except that the ink receiving layer was changed to the following composition. <Formulation of ink receiving layer coating liquid> 80 parts of porous starch particles (porous starch: porous starch particles produced by reacting raw starch degrading enzyme on corn starch particles, porosity 45%, manufactured by Sanei Saccharification) Synthetic amorphous silica (Fine Seal X37B, manufactured by Tokuyama Soda) 20 parts PVA (PVA117, Kuraray, 10% aqueous solution) 100 parts Water 350 parts

Examples 7 and 8 The same procedures as in Example 5 were carried out except that a 0.1% aqueous solution of sulfuric acid was appropriately added to the ink receiving layer coating solution to adjust the pH of the coating solution to 5.0 and 4.3. In the same manner, coating type ink jet recording sheets of Examples 7 and 8 were obtained.

Example 9 90 parts of LBKP (freeness: 380 mlcsf) and NBKP
(Freeness: 480 mlcsf) For 100 parts of wood pulp consisting of 10 parts, 20 parts of talc, 3 parts of sulfuric acid band, 0.2 parts of commercially available rosin sizing agent, 0.3 parts of commercially available cationized starch
After preparing the part, it was paper-made with a fourdrinier paper machine to obtain an acidic base paper having a basis weight of 120 g / m ² . Except for using this acidic base paper as the support,
A coating type ink jet recording sheet of Example 9 was obtained in the same manner as in Example 5.

Example 10 A 10% sulfuric acid band was applied to the front and back surfaces of the neutral paper used in Example 5.
The aqueous solution was permeated using a one-step processor so that the dry coating amount was 1 g / m ^2, and then dried to obtain a pseudo acidic paper. A coating type inkjet recording sheet of Example 10 was obtained in the same manner as in Example 5 except that this pseudo acidic paper was used as a support.

Comparative Example 5 A coating type ink jet recording sheet of Comparative Example 5 was obtained in the same manner as in Example 5, 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 Soda) 100 parts PVA (PVA117, Kuraray, 10% aqueous solution) 300 parts Water 320 parts

Comparative Example 6 A coating type ink jet recording sheet of Comparative Example 6 was obtained in the same manner as in Example 5, 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

Comparative Example 7 The procedure of Comparative Example 7 was repeated except that the porous starch particles were replaced by starch particles having no pores (corn starch particles, manufactured by Sanwa Starch Kogyo Co., Ltd.). A coating type ink jet recording sheet was obtained.

As described above, Examples 5 to 10 and Comparative Examples 5 to 7
Table 2 summarizes the evaluation results of the second ink jet recording sheet of the present invention shown in FIG.

[0131]

[Table 2]

(Evaluation) In the case of the ink jet recording sheets of the present invention shown in Examples 5 to 10, as shown in Table 2, while maintaining the image density and the ink absorbency at the same levels as Comparative Examples 4 and 5, And the fixability of the pigment ink could be improved. Particularly, in Examples 7 to 10, since the surface pH of the ink receiving layer was 6.0 or less, yellowing of blank paper could be further suppressed.

On the other hand, in both Comparative Examples 5 and 6, since the ink receiving layer was mainly composed of conventionally known synthetic amorphous silica or alumina particles, the white paper was significantly yellowed and the fixability of the pigment ink was poor. Was. Comparative Example 4 had a low image density due to the use of ordinary starch particles having no pores,
Ink absorption and pigment ink fixability were also poor.

[0134]

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 of silver halide photography, and stable long-term storage property of the ink-jet recording sheet and ink-jet recording suitability using a pigment ink will be extremely important. ADVANTAGE OF THE INVENTION According to this invention, yellowing of white paper and the fixability of pigment ink can be improved.

[Brief description of the drawings]

FIG. 1 is an electron micrograph of the surface of an ink receiving layer of a second inkjet recording sheet of the present invention.

Claims (8)

[Claims] 1. An ink-jet recording sheet of a non-coated type obtained by paper-making a slurry containing natural or synthetic fibers as a main component, characterized in that said sheet contains porous starch particles. 2. TAPPI of an ink jet recording sheet
2. The ink jet recording sheet according to claim 1, wherein the surface pH defined by T529 is 6.0 or less. 3. The ink jet recording sheet according to claim 1, wherein the ink jet recording sheet is an acidic paper made from a slurry containing natural pulp as a main component. 4. The ink jet recording sheet according to claim 1, wherein the ink jet recording sheet is a pseudo acidic paper obtained by coating a sulfuric acid band solution on neutral paper made from a slurry containing natural pulp as a main component. Ink jet recording sheet. 5. An ink jet recording sheet of a coating type comprising an ink receiving layer provided on at least one surface of a support, wherein the ink receiving layer contains porous starch particles. 6. The ink jet recording sheet according to claim 5, wherein the surface pH of the ink receiving layer specified by TAPPI T529 is 6.0 or less. 7. The ink jet recording sheet according to claim 5, wherein the support is an acidic paper made from a slurry containing natural pulp as a main component. 8. The ink-jet printer according to claim 5, wherein the support is a pseudo-acid paper in which a sulfuric acid band solution is impregnated on neutral paper made from a slurry containing natural pulp as a main component. Recording sheet.