JP2003211822A - Inkjet recording sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet recording sheet with excellent ink absorption and with excellent color developing density, water resistance, light-resistance and yellowing resistance. <P>SOLUTION: The inkjet recording sheet is characterized by a recording sheet having a layer comprising cationic organic particles in at least one layer on a sheet-like substrate and cationic degree of the cationic organic particles being +100 to +3,000 μeq/g. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to printers and plotters using an ink jet recording system, and in particular, the outermost surface does not have photographic-like gloss,
The present invention relates to a so-called matte ink jet recording sheet.

[0002]

2. Description of the Related Art An ink jet recording system is a system for recording images, characters, etc. by ejecting minute droplets of ink by various operating principles and adhering them to a recording sheet such as paper. The recording method is characterized by high speed, low noise, easy multicoloring, great flexibility in recording patterns, no need for development and fixing, and various recording devices for various figures including Kanji and color images. Is rapidly spreading in the use of.
Furthermore, the image formed by the multicolor inkjet method is
By expanding the resolution and color reproduction range, it is possible to obtain records that are comparable to multicolor printing by the plate making method and printing by the color photographic method, and for applications that require less number of copies than those by photographic technology. Since it is inexpensive, it is being widely applied to the field of full-color image recording.

Further, printers and plotters using the ink jet system have been required to have a higher resolution and a wider color reproduction range due to the demand for further improvement in image quality from the market. This is dealt with by increasing the discharge amount. Therefore, an increase in the ink receiving capacity commensurate with the ejection amount has become an important technical subject for the recording sheet, and it is essential to secure a high ink receiving capacity and to apply a coating layer having good color development.

In general, the ink liquid used in the ink jet recording method has an anionic water-soluble dye dissolved in a solvent containing water as a main component. When the ink absorbability is improved by using a large amount of the dye and increasing the voids, the dye deeply penetrates into the inside of the recording sheet, resulting in a problem that the coloring density is lowered. In order to improve the color density, it is necessary to fix the dye in the ink on the surface layer of the recording sheet as much as possible. Further, in order to improve the water resistance, that is, to prevent the dye from being released when the recording sheet comes into contact with water, it is necessary to fix the dye on the surface layer of the recording sheet.
In order to solve this problem, a cationic polymer is contained in the coating layer, and a method of fixing the anionic dye has been proposed, but if the amount of the cationic polymer is increased, the content of the inorganic particles decreases, There is a problem that it becomes difficult to secure ink absorbency.

Further, in recent years, due to the technical progress of the ink jet recording system, it has become possible to obtain a clear image and excellent print quality, and it has become possible to obtain an image quality comparable to that of a photograph. However, compared with photographs, there is a problem in light resistance, that is, fading of a printed image when stored for a long period of time, and yellowing resistance, that is, yellowing of the surface of a recording sheet when stored for a long period of time. However, the recording sheet currently contains a large amount of fine inorganic particles in the coating layer to exhibit ink absorbency and color density, and in order to further improve performance, finer inorganic particles should be selected. Is becoming. Generally, silica and alumina are preferably used as the inorganic particles, but the finer the surface area, the more dramatically the surface area increases, and the high surface activity of the inorganic particles significantly reduces light resistance and yellowing resistance. There is such a problem.

From the above, it is currently difficult to obtain an ink jet recording sheet satisfying all of the ink absorbency, color density, water resistance, light resistance, and yellowing resistance by the current technology. An example of the current technology is as follows.

For example, Japanese Patent Laid-Open No. 11-11011 discloses that
An inkjet recording sheet is disclosed in which a coating composition comprising cationic colloidal particles containing alumina as a main component and a cationic latex is cast-coated at a temperature higher than the glass transition temperature of the latex.
The amount of the cationic colloidal particles containing alumina as the main component and the latex is preferably 2 to 70 parts by weight, and most preferably 3 to 30 parts by weight, based on 100 parts by weight of the cationic colloidal particles. Further, although the detailed definition as a cationic latex is not clear, it is cationized using a cationic group, or the latex surface is cationized with a cationic surfactant. In the examples, the cationic surfactant is used. The cationic latex produced in. Has been evaluated.

Further, in Japanese Patent Laid-Open No. 11-123867,
An inkjet recording sheet is disclosed in which a white pigment layer contains a cationic acrylic resin emulsion. The white pigment is inorganic particles such as clay / calcium carbonate and titanium oxide, or organic particles such as polyethylene, polystyrene and polyacrylate, and the ratio of the cationic acrylic resin emulsion mixed in the white pigment layer is 100 weight of the white pigment. 100 parts by dry weight solid content per part
5 parts by weight, most preferably 50 to 30 parts by weight. Further, the amount of the cationic monomer used for obtaining the cationic acrylic resin emulsion is preferably 1 to 5% by weight based on all the monomers.

Further, JP-A No. 11-58943 discloses an ink jet recording material obtained by coating a support with a coating solution containing non-spherical silica and a water-dispersible cationic polymer and drying the coating solution. ing. The content of the water-dispersible cationic polymer in the ink receiving layer is 1 to 30% by weight.
Then, it is preferable that the content of the inorganic particles is 75 to 95% by weight.

Further, JP-A No. 11-20306 discloses an ink jet recording paper having an ink absorption layer containing a cationic mordant having a mordant power for anionic dyes on a support. Inorganic fine particles of silica or alumina are contained in the ink absorbing layer, and the amount of the cationic mordant is 0.01 to 0.3 by weight ratio with respect to the inorganic particles, and the cationic mordant is an aqueous solution having an average molecular weight of 50,000 or less. It is preferably a mordant.

Further, Japanese Patent Publication No. 7-53469 discloses an ink jet recording sheet having a coating layer composed of a pigment and a binder resin on a support, wherein the binder contains (a) a component containing a fatty acid vinyl ester, b) 0.05-
Disclosed is an inkjet recording sheet which is a cationic copolymer comprising 0.4 mol% of a cationic monomer having an ethylenically unsaturated group and a tertiary amino group or a quaternary ammonium group. The pigment is fine particle silica, etc., and the content of the cationic copolymer in the coating layer is 5
It is preferably ˜50% by weight.

Further, JP-A-9-59898 discloses that an ethylene structural unit is 80 to 98.5 mol%, an acrylate structural unit is 0.5 to 10 mol%, and a cationic acrylamide structural unit is 1 to 10 mol% on a paper substrate. Disclosed is a resin-coated paper for printing, which is provided with a coating layer containing a copolymer emulsion having a weight average molecular weight of 1,000 to 50,000. The printing resin-coated paper has good offset printing suitability.

[0013]

DISCLOSURE OF THE INVENTION An object of the present invention is to solve the above problems by providing an ink jet recording sheet which is excellent in ink absorption and is excellent in color density, water resistance, light resistance and yellowing resistance. To provide.

[0014]

DISCLOSURE OF THE INVENTION As a result of intensive studies aimed at solving the above problems, the present inventors have found that at least one layer on a sheet-like support has at least one layer of cationic organic particles having a specific degree of cationization. The present invention has been completed by finding that the ink-jet recording sheet containing the composition is excellent in ink absorbability, and also excellent in color density, light resistance and yellowing resistance.

That is, the present invention is an ink jet recording sheet having at least one layer containing cationic organic particles on a sheet-like support, wherein the cationic organic particles have a cationization degree of +100 to +3000 μeq.
/ G, and the 75 ° specular glossiness based on JIS-Z-8741 of the outermost surface of the inkjet recording sheet is 5
It is an ink jet recording sheet characterized by being 0% or less, wherein the cationic organic particles are (co) polymers of (meth) acrylic acid ester, styrene- (meth).
Acrylic ester (co) polymer, methylmethacrylate-butadiene copolymer, styrene-butadiene copolymer, urethane polymer, epoxy polymer, ethylene-vinyl acetate copolymer, melamine polymer, urea polymer or olefin polymer Organic particles selected from materials of one kind or two or more kinds of copolymers selected from polymers, those polymerized using an initiator having an amidino group, (A) (Meth) acrylic acid alkyl ester and / or styrene, (B) amino group-containing (meth) acrylate-based monomer and / or amino group-containing (meth) acrylamide-based monomer, and (C) another copolymerizable monomer Characterized in that it is a cationic emulsion particles obtained by copolymerizing Ink is a jet recording sheet.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION The ink jet recording sheet of the present invention is characterized by having at least one layer containing cationic organic particles having a specific degree of cationization on a sheet-like support. It is a recording sheet for.

The details will be described below. [Measurement method of degree of cationization] A particle surface charge measuring device (PC
D meter; German PC model PC
D03 pH) for colloid titration 1 / 400N
Polyvinyl potassium sulfate solution (manufactured by Wako Pure Chemical Industries, Ltd.)
It was determined by titration with. The range of the degree of cationization of the cationic organic particles in the present invention is +100 to +3000 μ.
eq / g, preferably +100 to +1500 μe
q / g. If the degree of cationization is less than +100 μeq / g, the dye cannot be sufficiently fixed, the water resistance may decrease, and the color density may be poor. In addition, the light resistance is also reduced. When the degree of cationization exceeds +3000 μeq / g, it becomes difficult to produce the organic particles, and the ink absorbability decreases.

[Measurement Method of Specular Glossiness] The specular glossiness in the present invention is a measurement of the specular glossiness of the recording sheet surface at 75 ° based on JIS Z8741. For example, it can be measured with a variable angle gloss meter GM-3D (manufactured by Murakami Color Research Laboratory Co., Ltd.) or the like. The recording sheet of the present invention relates to a so-called matte ink jet recording sheet having a specular gloss of 50% or less at 75 °.

[Cationic Organic Particles] A preferred embodiment of the cationic organic particles in the present invention is water-insoluble thermoplastic polymer particles having a cationic functional group such as an amino group, and the polymer species is (meth). Acrylic polymer ((meth) acrylic ester (co) polymer), styrene- (meth) acrylic polymer (styrene and (meth) acrylic ester (co) polymer),
MBR-based polymer (methyl methacrylate-butadiene copolymer), SBR-based polymer (styrene-butadiene copolymer), urethane-based polymer, epoxy-based polymer, EVA-based polymer (ethylene-vinyl acetate copolymer), melamine-based polymer, It is a urea polymer or an olefin polymer. Furthermore, since the acrylic polymer and the styrene- (meth) acrylic polymer are excellent in yellowing resistance of the recording sheet for a long period of time,
This is a more preferable aspect.

In a further preferred embodiment of the cationic organic particles, (A) (meth) acrylic acid alkyl ester-based monomer and / or styrene and (B) amino group-containing (meth) acrylate-based monomer and / or amino group-containing It is obtained by copolymerizing a (meth) acrylamide monomer and (C) another copolymerizable monomer.
It is a cationic organic particle.

Hereinafter, each thermoplastic polymer will be described more specifically. Specific examples of the (A) (meth) acrylic acid alkyl ester-based monomer include acrylic acid esters; methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, n-amyl acrylate, isoamyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate, octyl acrylate, decyl acrylate, dodecyl acrylate, octadecyl acrylate, cyclohexyl acrylate, phenyl acrylate, benzyl acrylate, methacrylic acid esters; methyl methacrylate, ethyl methacrylate,
Isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-amyl methacrylate, isoamyl methacrylate, n-hexyl methacrylate, 2-ethylhexyl methacrylate, octyl methacrylate, decyl methacrylate, dodecyl methacrylate, octadecyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, benzyl methacrylate, etc. , Other carbon atoms 1 to 12
Alkyl acrylates, other C1-C1
The methacrylate of 2 etc. are mentioned, These 1 type, or 2 or more types can be selected. As (A), methyl acrylate, n-butyl acrylate, isobutyl acrylate, ethyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, ethyl methacrylate and 2-ethylhexyl methacrylate are preferable. Specific examples of the (B) amino group-containing (meth) acrylate-based monomer and / or amino group-containing (meth) acrylamide-based monomer include, for example, N, N-dimethylaminoethyl acrylate, N, N-dimethylaminoethyl methacrylate, N, N-dimethylaminopropyl acrylate, N, N-dimethylaminopropyl methacrylate, N, Nt-butylaminoethyl acrylate,
N, N-t-butylaminoethyl methacrylate, N,
Aminoalkyl acrylates or aminoalkyl methacrylates such as N-monomethylaminoethyl acrylate and N, N-monomethylaminoethyl methacrylate;
N, N-dimethylacrylamide, N, N-dimethylmethacrylamide, N, N-diethylacrylamide,
N, N-diethylmethacrylamide, N, N-dimethylaminopropylacrylamide, N, N-dimethylaminopropylmethacrylamide, N, N-dimethylaminoethylacrylamide, N, N-dimethylaminoethylmethacrylamide, N-isopropylacrylamide N-aminoalkyl acrylamides or N-aminoalkyl methacrylamides such as; quaternary chlorides with halogenated methyl groups such as chlorine, bromine, iodine, etc., halogenated ethyl groups, halogenated benzyl groups, etc. Quaternary salts of alkyl acrylates or aminoalkyl methacrylates and N-aminoalkylacrylamides or N-aminoalkylmethacrylamides;
Acryloylmorpholine, 2- (2'-hydroxy-
5'-methacryloyloxyethylphenyl) -2H-
Benzotriazole, 2- (2'-hydroxy-5'-
Methacryloyloxyphenyl) -benzotriazole, 2-hydroxy-4- (2-methacryloyloxy) ethoxybenzophenone, 2- (2'-hydroxy-5'-methacryloyloxyphenyl) -5-chlorobenzotriazole, 1,2,2 , 6,6-Pentamethyl-4-piperidyl methacrylate, 2,2,6,6-
Tetramethyl-4-piperidyl methacrylate and the like can be mentioned, and one or more of these can be selected. (C) Specific examples of other copolymerizable monomers include, for example, acrylic acid, methacrylic acid, itaconic acid,
Unsaturated carboxylic acids such as maleic acid, fumaric acid, maleic anhydride, itaconic anhydride, fumaric anhydride; 2-hydroxyethyl acrylate, hydroxypropyl acrylate, 4-hydroxybutyl acrylate, 2-hydroxyethyl methacrylate, hydroxypropyl methacrylate, Hydroxyl group-containing vinyls such as 4-hydroxybutylmethacrylate; aromatic vinyls such as 2-methylstyrene, t-butylstyrene, chlorostyrene, vinylanisole, vinylnaphthalene and divinylbenzene; acrylamide, methacrylamide, N-methylolmethacryl Amides, amides such as N-methylol acrylamide, diacetone acrylamide, maleic amide;
Vinyl esters such as vinyl acetate and vinyl propionate; vinylidene halides such as vinylidene chloride and vinylidene fluoride; vinyl chloride, vinyl ether, vinyl ketone, vinylamide, chloroprene, ethylene, propylene, isoprene, butadiene, chloroprene, vinylpyrrolidone, 2 -Methoxyethyl acrylate, 2-ethoxyethyl acrylate, glycidyl acrylate,
Glycidyl methacrylate, allyl glycidyl ether, acrylonitrile, methacrylonitrile, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, polypropylene glycol dimethacrylate, neopentyl glycol dimethacrylate, 1,3-butylene glycol Dimethacrylate, 1,6-hexanediol dimethacrylate, neopentyl glycol dimethacrylate, polyethylene glycol diacrylate, 1,6
-Hexanediol diacrylate, neopentyl glycol diacrylate, tripropylene glycol diacrylate, polypropylene glycol diacrylate, trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, tetramethylolmethane triacrylate, tetramethylolmethane tetraacrylate, allyl methacrylate , Dicyclopentenyl acrylate, dicyclopentenyl oxyethyl acrylate, isopropenyl-α, α-dimethylbenzyl isocyanate, allyl mercaptan, etc., and one or more of them can be selected.

Further, (A) (meth) acrylic acid alkyl ester-based monomer and / or styrene, (B) amino group-containing (meth) acrylate-based monomer and / or amino group-containing (meth) acrylamide-based monomer, and (C) ) The composition ratio of other copolymerizable monomers is such that (A) is 10% by weight to 99% by weight, (B) is 1% by weight to 90% by weight, and (C) is 0 based on the total weight. weight%
Is preferably 30% by weight to 30% by weight, more preferably 40% by weight to 99% by weight of (A) and 1% by weight of (B).
60% by weight, (C) 0% by weight to 30% by weight, more preferably (A) 60% by weight to 98% by weight, (B) 2% by weight to 40% by weight, (C) 0% by weight. % -30% by weight
Is.

If the content of (A) is less than 10% by weight, the hydrophilicity of the cationic organic particles may be increased and the water resistance and ink absorbability may be lowered. If the content of (A) exceeds 98% by weight, the ink content may be reduced. Since the fixation of the dye is likely to be poor, the color density may decrease. If (B) is less than 1% by weight, the degree of cationization is less than +100 μeq / g, immobilization of the ink dye is likely to be insufficient, and thus the color density and water resistance may decrease, and If it exceeds 90% by weight, the degree of cationization will greatly exceed +3000 μeq / g, the hydrophilicity of the cationic organic particles will increase and the water resistance will decrease, and the ink absorbency will decrease due to the reduction of fine voids. There are cases.

[Molecular Weight of Cationic Organic Particles] The weight average molecular weight of the cationic organic particles of the present invention is 600.
00 or more is preferable, and 100,000 or more is more preferable. When the weight average molecular weight is less than 60,000, the cationic organic particles are likely to be deformed, the voids are reduced, and the ink absorbability may be lowered.

[Particle Size of Cationic Organic Particles] The average particle size of the cationic organic particles of the present invention is 0.01 μm.
m-5 μm is preferable, and more preferably 0.05 μm-
It is 1 μm. If the average particle size is less than 0.01 μm, fine voids may be reduced and ink absorbability may be reduced.
If it exceeds 5 μm, the color density may decrease.

[Glass Transition Temperature (Tg) of Cationic Organic Particles] The glass transition temperature of the cationic organic particles of the present invention is preferably 60 ° C. or higher. When the glass transition temperature is lower than 60 ° C, fine voids in the surface layer are likely to be reduced, and the ink absorbability may be lowered. Further, when the coating layer is dried, if the drying temperature is high, fine voids are reduced. Therefore, the drying temperature must be lowered, which may reduce the production efficiency. The glass transition temperature in this specification can be obtained from a DSC curve based on JIS K7121.

[Method for Producing Cationic Organic Particles] The cationic organic particles used in the present invention can be produced by a conventionally known emulsion polymerization method or mechanical emulsification method. For example, in the emulsion polymerization method, in the presence of a dispersant and an initiator, a method of charging and polymerizing various monomers at once,
There is a method of polymerizing while continuously supplying a monomer.
The polymerization temperature at that time is usually 30 to 90 ° C.,
An aqueous dispersion of substantially organic particles is obtained.

The dispersant preferably used here includes a cationic surfactant and / or a nonionic surfactant. The details will be described below.

Specific examples of the cationic surfactant include:
For example, lauryl trimethyl ammonium chloride,
Stearyl trimethyl ammonium chloride, cetyl trimethyl ammonium chloride, distearyl dimethyl ammonium chloride, alkylbenzyl dimethyl ammonium chloride, lauryl betaine, stearyl betaine, lauryl dimethylamine oxide, lauryl carboxymethyl hydroxyethyl imidazolinium betaine, coconut amine acetate, stearyl amine Examples thereof include acetate, alkylaminganidin polyoxyethanol, alkylpicolinium chloride and the like, and one or more of these can be selected.

Specific examples of the nonionic surfactant include:
For example, polyoxyethylene lauryl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene oleyl phenyl ether, polyoxyethylene nonyl phenyl ether, oxyethylene / oxypropylene block copolymer, tert-octylphenoxyethyl polyethoxyethanol, nonylphenoxyethyl poly Ethoxy ethanol and the like can be mentioned, and one or more of these can be selected.

Further, a cationic water-soluble polymer and / or a nonionic water-soluble polymer can be used as the dispersant. Examples of the cationic water-soluble polymer include cationized polyvinyl alcohol, cationized starch, cationized polyacrylamide, cationized polymethacrylamide, polyamide polyurea, polyethyleneimine, a copolymer of allylamine or a salt thereof, and epichlorohydrin-
Dialkylamine addition polymer, diallylalkylamine or its salt polymer, diallyldialkylammonium salt polymer, diallylamine or its salt and sulfur dioxide copolymer, diallyldialkylammonium salt-sulfur dioxide copolymer, diallyldialkylammonium salt And a diallylamine or a salt or derivative thereof, a polymer of a quaternary salt of dialkylaminoethyl (meth) acrylate, a diallyldialkylammonium salt-acrylamide copolymer, an amine-carboxylic acid copolymer, and the like. 1 type, or 2 or more types can be selected.

As the nonionic water-soluble polymer, polyvinyl alcohol or its derivative; starch derivative such as oxidized starch, etherified starch, phosphoric esterified starch; polyvinylpyrrolidone such as polyvinylpyrrolidone or polyvinylpyrrolidone copolymerized with vinyl acetate. Derivatives; derivatives thereof Cellulose derivatives such as carboxymethylcellulose and hydroxymethylcellulose; polyacrylamide or derivatives thereof; polymethacrylamide or derivatives thereof; gelatin, casein, etc., and one or more of these can be selected. .

The amount of the dispersant used is not particularly limited, but is usually 0.0 based on the total weight of the monomers to be copolymerized.
It is 2 to 20% by weight.

As the initiator used for the polymerization, a usual radical initiator can be used, and specific examples thereof include
Hydrogen peroxide; persulfates such as ammonium persulfate and potassium persulfate; cumene hydroperoxide, t-butyl hydroperoxide, benzoyl peroxide,
t-butylperoxy-2-ethylhexanoate, t
-Organic peroxides such as butyl peroxybenzoate and lauroyl peroxide; azobisisobutyronitrile, 2,2'-azobis (2-amidinopropane) dihydrochloride, 2,2'-azobis [2- (N -Phenylamidino) propane] dihydrochloride, 2,2'-azobis {2-
[N- (4-chlorophenyl) amidino] propane} dihydrochloride, 2,2′-azobis {2- [N- (4-hydroxyphenyl) amidino] propane} dihydrochloride, 2,
2'-azobis [2- (N-benzylamidino) propane] dihydrochloride, 2,2'-azobis [2- (N-allylamidino) propane] dihydrochloride, 2,2'-azobis {2- [ N- (2-hydroxyethyl) amidino] propane} dihydrochloride, 2,2′-azobis {2-methyl-N
-[1,1-bis (hydroxymethyl) -2-hydroxyethyl] propionamide}, 2,2'-azobis {2-methyl-N- [1,1-bis (hydroxymethyl) ethyl] propionamide}, 2,2'-azobis [2-methyl-N- [2-hydroxyethyl) propionamide], 2,2'-azobis (isobutyramide)
Azo compounds such as dihydrates; or redox obtained by combining these with metal ions such as iron ions and reducing agents such as sodium sulfoxylate, formaldehyde, sodium pyrosulfite, sodium bisulfite, L-ascorbic acid and Rongalit Examples thereof include an initiator, and one or more of these can be selected.

Typical amounts of initiators used are from 0.1 to 5% by weight, based on the total weight of monomers to be copolymerized.

If necessary, mercaptans such as t-dodecyl mercaptan and n-dodecyl mercaptan,
It is also possible to use allyl compounds such as allyl sulfonic acid, methallyl sulfonic acid and their soda salts as a molecular weight regulator.

[Content of Cationic Organic Particles] The content of the cationic organic particles in the layer containing the cationic organic particles of the present invention is preferably from 3 to 80% by weight, more preferably from 5 to 50% by weight. %. If it is less than 3% by weight, immobilization of the ink dye tends to be insufficient, and the color density and water resistance may decrease. If it is 80% by weight or more, the ink absorptivity may decrease.

[Other Additives] In the layer containing the cationic organic particles of the present invention, for the purpose of improving the surface strength,
A polymer having a binder function may be contained.
Examples of the polymer having a binder function include water-soluble polymers and water dispersions of water-insoluble polymers. The details will be described below.

Examples of the water-soluble polymer include cationic water-soluble polymers such as cationized polyvinyl alcohol, cationized starch, cationized polyacrylamide, cationized polymethacrylamide, polyamide polyurea, polyethyleneimine, allylamine and salts thereof. Copolymer, epichlorohydrin-dialkylamine addition polymer, diallylalkylamine or its salt polymer, diallyldialkylammonium salt polymer, diallylamine or its salt and sulfur dioxide copolymer, diallyldialkylammonium salt-sulfur dioxide copolymer Coalesce, copolymer of diallyldialkylammonium salt and diallylamine or its salt or derivative, polymer of quaternary salt of dialkylaminoethyl (meth) acrylate, diallyldialkylacetate Moniumu salt - acrylamide copolymer, amine - carboxylic acid copolymer and the like.

Further, it is a nonionic water-soluble polymer,
Polyvinyl alcohol or its derivatives; oxidized starch,
Starch derivatives such as etherified starch and phosphoric acid esterified starch; polyvinylpyrrolidone derivatives such as polyvinylpyrrolidone obtained by copolymerizing polyvinylpyrrolidone or vinyl acetate; derivatives thereof cellulose derivatives such as carboxymethylcellulose and hydroxymethylcellulose; polyacrylamides or derivatives thereof; Polymethacrylamide or a derivative thereof; gelatin, casein and the like can be mentioned.

Further, as the water dispersion of the water-insoluble polymer, for example, a cationic and / or nonionic acrylic polymer ((co) polymer of (meth) acrylic acid ester), styrene-acrylic polymer (styrene and (Co) polymer of (meth) acrylic acid ester), MBR
-Based polymer (methyl methacrylate-butadiene copolymer), SBR-based polymer (styrene-butadiene copolymer), urethane-based polymer, epoxy-based polymer, EV
Examples thereof include an aqueous dispersion of an A-based polymer (ethylene-vinyl acetate copolymer).

In particular, polyvinyl alcohol, cationized polyvinyl alcohol, acrylic polymers ((meth) acrylic acid ester (co) polymers), styrene-acrylic polymers (styrene and (meth)) are used because of their excellent yellowing resistance. Acrylic ester (co) polymer)
The water dispersion of is preferred. In the case of an aqueous dispersion, the glass transition temperature of the polymer is preferably 60 ° C or lower.

The amount of the polymer having a binder function used is preferably 0 to 50 parts by weight, more preferably 0 to 35 parts by weight, and further preferably 0 to 35 parts by weight, based on the total weight of the cationic organic particles and the inorganic particles described below. Preferably 0-2
0 parts by weight. If the amount is more than 50 parts by weight, the voids are likely to be reduced and the ink absorbency may be lowered.

Further, the layer containing the cationic organic particles of the present invention may contain inorganic particles. As the inorganic particles, specifically, for example, light calcium carbonate, heavy calcium carbonate, magnesium carbonate, kaolin, clay, talc, calcium sulfate, barium sulfate, titanium dioxide, zinc oxide, zinc hydroxide, zinc sulfide, carbonic acid. Zinc, hydrotalcite, aluminum silicate, diatomaceous earth,
Examples thereof include calcium silicate, magnesium silicate, synthetic amorphous silica, colloidal silica, alumina, colloidal alumina, pseudo-boehmite, aluminum hydroxide, lithobone, zeolite and magnesium hydroxide. In order to obtain a high porosity and improve ink absorbency, silica or alumina is preferable.

In addition to the above, the layer containing the cationic organic particles of the present invention contains an antistatic agent, an antioxidant, a dry paper strength enhancer, a wet paper strength enhancer, a water resistance agent, a preservative, and an ultraviolet ray. Absorbers, light stabilizers, optical brighteners, colored pigments, colored dyes, penetrants, foaming agents, release agents, foam suppressors, defoamers, fluidity improvers, thickeners, pigment dispersants, It may contain a cationic fixing agent or the like.

[Structure of Recording Sheet] A preferable example of the structure of the recording sheet of the present invention is that the layer containing the cationic organic particles is used as a layer related to ink reception, and more preferably. It is preferably on the outermost layer on the recording surface side of the recording sheet.

The amount of the layer containing the cationic organic particles of the present invention is usually 1 as a basis weight on a sheet-like support.
It is up to 300 g / m ² , but is not particularly limited.

[Sheet support type] In the present invention, the support is a support conventionally used for ink jet recording sheets, for example, plain paper, art paper, coated paper, cast coated paper, resin coated paper, resin. Paper support such as impregnated paper, non-coated paper, coated paper, paper support with both sides coated with polyolefin, plastic support, non-woven fabric, cloth, woven fabric, metal film, metal plate, and composites obtained by laminating these. A support can be used.

Examples of the plastic support include plastic sheets and films of polyethylene, polypropylene, polystyrene, polyethylene terephthalate, polyethylene naphthalate, triacetyl cellulose, polyvinyl chloride, polyvinylidene chloride, polyimide, polycarbonate, cellophane, polynylon and the like. Etc. are preferably used. These plastic supports may be transparent, translucent, or opaque depending on the application.

It is also preferable to use a white plastic film as the support. As the white plastic support, a small amount of white pigment such as barium sulfate, titanium oxide or zinc oxide is contained in the plastic, a foamed plastic support provided with a large number of fine voids to provide opacity, and a white plastic support. A support provided with a layer having a pigment (titanium oxide, barium sulfate) can be used.

In the present invention, the shape of the support is not limited, but in addition to the commonly used film, sheet, plate, etc., it has a cylindrical shape such as a beverage can, a disk shape such as CD or CD-R, Other materials having a complicated shape can also be used as the support.

[0052]

EXAMPLES Examples of the present invention will be described below.
However, the present invention is not limited to these examples.
The parts and% shown in the examples are unless otherwise specified.
Parts by weight and% by weight. [Example 1] <Preparation of cationic organic particles> 195.9 parts of deionized water
And stearyl trimethyl ammonium chloride 0.1
Parts into a reaction vessel and heated to 70 ° C. under a nitrogen stream,
2,2'-azobis (2-amidinopropane) dihydrochloride
0.6 parts was added. Apart from this, methylmethacry
Rate 74.0 parts, n-butyl acrylate 10.0
Part of N, N-dimethylaminopropyl acrylamide
Methyl chloride quaternary salt 16.0 parts with deionized water 40 parts
Stearyl trimethyl ammonium chloride
Make an emulsified mixture that is emulsified using 3 parts and
The mixture was dropped into the reaction vessel in 4 hours, and then at the same temperature.
Hold for 4 hours. Continuously 2,2'-azobis (2-
0.1 part of amidinopropane) dihydrochloride was added, and
The temperature was maintained for 3 hours to complete the polymerization. as a result,
Emulsion composition in which cationic organic particles are dispersed in water
Is obtained, the cationization degree +832 μeq / g, non-volatile content
30%, pH 5, average particle size 199n by light scattering measurement
m, and from the DSC curve based on JIS K 7121
The determined glass transition temperature was 85.0 ° C. <Preparation of recording sheet> 30 parts of the above cationic organic particles,
Silica (Fineseal X-37B; Tokuyama Corporation)
100 parts, polyvinyl alcohol (PVA117;
Mix 20 parts by Kuraray Co., Ltd. so that the solid content becomes 20%.
Combined, the resulting coating liquid has a basis weight of 105 g / m ²On fine paper,
20 g / m in an absolutely dry state²So that the coating amount is
It was dried at 60 ° C. for 100 seconds. As a result,
A recording sheet was obtained.

[Comparative Example 1] <Preparation of cationic organic particles> 195.9 parts of deionized water
And stearyl trimethyl ammonium chloride 0.1
Parts into a reaction vessel and heated to 70 ° C. under a nitrogen stream,
2,2'-azobis (2-amidinopropane) dihydrochloride
0.6 parts was added. Apart from this, methylmethacry
Rate 74.0 parts, n-butyl acrylate 10.0
Part of N, N-dimethylaminopropyl acrylamide
Methyl chloride quaternary salt 1.0 part in deionized water 40 parts
Stearyl trimethyl ammonium chloride 0.3
Part to make an emulsified mixture that has been emulsified
The product was added dropwise to the reaction vessel in 4 hours, and then at the same temperature.
Held for 4 hours. Continuously, 2,2'-azobis (2-a
(Midinopropane) dihydrochloride 0.1 part was added, and
The temperature was maintained for 3 hours to complete the polymerization. As a result,
An emulsion composition in which thione organic particles are dispersed in water
Obtained, cationization degree +81 μeq / g, nonvolatile content 30
%, PH 5, average particle size 210 nm by light scattering measurement,
And from the DSC curve based on JIS K 7121
The glass transition temperature was 83.0 ° C. <Preparation of recording sheet> 30 parts of the above cationic organic particles,
Silica (Fineseal X-37B; Tokuyama Corporation)
100 parts, polyvinyl alcohol (PVA117;
Mix 20 parts by Kuraray Co., Ltd. so that the solid content becomes 20%.
Combined, the resulting coating liquid has a basis weight of 105 g / m ²On fine paper,
20 g / m in an absolutely dry state²So that the coating amount is
It was dried at 60 ° C. for 100 seconds. As a result, in Comparative Example 1
A recording sheet was obtained.

[Evaluation Method] The quality evaluation results of the recording sheet are shown in Table 1 [Table 1]. The evaluation was performed by the following method.

<Measurement Method of Degree of Cationization> A sample emulsion whose solid content concentration was adjusted to 1% was used as a particle surface charge measuring device (PCD meter; Mo manufactured by Mutec, Germany).
del PCD 03 pH) and titrated with a 1/400 N polyvinyl potassium sulfate solution for colloid titration (manufactured by Wako Pure Chemical Industries, Ltd.).

<Measurement Method of Coloring Density> Commercially available ink jet printer (PM2000 manufactured by Seiko Epson Corporation)
C) was used to perform solid printing of black ink, and the optical reflection density of the solid portion was measured with a Macbeth densitometer (RD-918).

<Measurement Method of Ink Absorption> Commercially available ink jet printer (PM20 manufactured by Seiko Epson Corporation)
00C), yellow ink, magenta ink,
Solid printing of cyan ink and black ink in the vertical direction,
Immediately after being discharged from the printer, the PPC paper was pressed on the upper portion, and the degree of transfer of the ink to the PPC paper was visually evaluated. The evaluation criteria are as follows. ◯: No ink transfer and excellent ink absorbability. Δ: The ink is slightly transferred, but the ink absorbency is at a practical level. X: A large amount of ink was transferred, and the ink absorbency was below the practical level. <Water resistance measuring method> Using a commercially available inkjet printer (PM2000C, manufactured by Seiko Epson Corporation),
Characters were printed with black ink, and this was immersed in city water at 30 ° C. for 2 minutes for evaluation. The printing state after immersion such as bleeding was visually determined. The evaluation criteria are as follows. ◯: Almost no bleeding or color density change. Δ: Practical level with slight bleeding and reduction in color density. X: There is bleeding and a decrease in color density, which is below the practical level. <Method of measuring light resistance> Using a commercially available inkjet printer (PM2000C manufactured by Seiko Epson Corporation),
Solid printing of magenta ink was performed. The printed recording sheet was irradiated with light for 100 hours using a xenon fade meter, and the residual ratio of the optical reflection density after the light irradiation to that before the light irradiation was defined as the light resistance. The optical reflection density was measured with a Macbeth densitometer (RD-918).

<Measurement Method of Yellowing Resistance> Using a carbon arc fade meter, the unprinted recording sheet was irradiated with light for 7 hours, and the color difference before and after the light irradiation was measured. Color difference (ΔE) is L ^* a ^* b ^* (display method according to CIE)
According to the above, based on the results of color measurement before and after light irradiation, ΔE = {(ΔL ^* ) ² + (Δa ^* ) ² + (Δb ^* ) ² } ^1/2 was calculated. The larger the color difference, the more the color deterioration occurs.

[0059]

[Table 1]

[0060]

According to the present invention, ink absorption is excellent,
Further, it is possible to provide an inkjet recording sheet excellent in color density, water resistance, light resistance, and yellowing resistance.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Takahiro Shikuma             580-32 Nagaura, Sodegaura-shi, Chiba Mitsui Chemicals, Inc.             Inside the company F-term (reference) 2C056 EA13 FC06                 2H086 BA01 BA15 BA19 BA21 BA31                       BA33 BA36 BA41                 4F006 AA02 AA12 AA17 AA35 AA36                       AA38 AB24 AB56 AB76 BA01                       BA03 BA15 CA01 DA04

Claims (7)

[Claims] 1. A recording sheet for inkjet having at least one layer containing cationic organic particles on a sheet-like support, wherein the cationic organic particles have a degree of cationization of +100 to +3000 μeq / g. An ink jet recording sheet characterized by the above. 2. The cationic organic particles are (co) polymers of (meth) acrylic acid ester, styrene- (meth).
Acrylic ester (co) polymer, methylmethacrylate-butadiene copolymer, styrene-butadiene copolymer, urethane polymer, epoxy polymer, ethylene-vinyl acetate copolymer, melamine polymer, urea polymer or olefin The inkjet recording sheet according to claim 1, wherein the recording sheet is an organic particle selected from the group consisting of one or two or more copolymer materials selected from the group of polymers. 3. The cationic organic particles, wherein (A) (meth) acrylic acid alkyl ester and / or styrene, (B) amino group-containing (meth) acrylate-based monomer and / or amino group-containing (meth) acrylamide. 3. The inkjet recording sheet according to claim 1, which is a cationic emulsion particle obtained by copolymerizing a base monomer and (C) another copolymerizable monomer. 4. The glass transition temperature of the cationic organic particles is 60 ° C. or higher.
The inkjet recording sheet according to any one of 1. 5. The weight average molecular weight of the cationic organic particles is 60,000 or more.
5. The inkjet recording sheet according to any one of 4 to 4. 6. The layer containing the cationic organic particles contains inorganic particles, and the outermost surface of JIS-Z-874.
The inkjet recording sheet according to any one of claims 1 to 5, wherein the 75 ° specular glossiness based on 1 is 50% or less. 7. The ink jet recording sheet according to claim 1, wherein the sheet-shaped support is a paper or a plastic sheet.