JPH10329290A - Recording sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve ink absorbing properties, water resistance and humidity resistance by specifying the gel molar fraction of an ink-receptive layer formed at least, on one of the faces of a base material. SOLUTION: A corona discharge treatment is applied to the surface of a biaxial oriented polyester film to form an ink receptive layer on a discharge- treated surface. This ink receptive layer shows a gel molar fraction of 50% or higher for one minute of exposure to water, preferably 80% or higher. When the gel molar fraction is 50% or lower, a print image runs so that it is hardly recognizable definitely and this phenomenon is not desirable. Further, the ink receptive layer is made up of a lower layer comprising a cationic copolymer and a crosslinked polyalkyleneoxide resin as principal components and an upper layer comprising a hydrophilic molecular resin as a principal component. This composition is desirable as the developing properties (brightness) can be improved. In addition, the thickness (d1) of the lower layer made up mainly of the cationic copolymer and the crosslinked polyalkyleneoxide resin and the thickness (d2) of the upper layer made up mainly of the hydrophilic polymer resin should preferably be d1>=d2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording sheet used for an electrophotographic copying machine, an ink jet printer, a thermal transfer printer, and the like. The present invention relates to a recording sheet having a high image density, a clear image color tone, and excellent water resistance and moisture resistance.

[0002]

2. Description of the Related Art With the spread of office automation in recent years, there has been an increasing demand for creating and recording documents in offices, and there has been a demand for a printer with low noise and excellent image quality. Electrophotographic copying machines, inkjet printers, and thermal transfer printers have been put to practical use to satisfy these requirements.
In recent years, color copying technology has reached the stage of completion, and color copiers / printers are gradually spreading. Above all, the spread of inkjet printers is remarkable.

[0003] Ink jet printers use ink that is difficult to dry in order to prevent clogging of nozzles, and the components of this ink are generally those in which binders, dyes, solvents, additives, and the like are dissolved in water. Therefore, it is necessary to use a recording sheet having good water absorption, and usually,
Special paper with good ink absorbency is used.

[0004]

In general, paper is inferior in water resistance, moisture resistance, and the like. If a plastic film not having these disadvantages can be applied, the advantages can be utilized in various fields.

When a sheet having low ink absorbency is used in recording by an ink jet printer, the ink may be insufficiently dried or not dried at all, and if a finger is rubbed or overlapped, a recording portion becomes dirty. And is virtually unusable. In order to improve these points, in order to improve the ink absorption of the substrate, for example, polyvinyl alcohol, starch, gelatin, cellulose derivatives such as hydroxyethylcellulose and methylcellulose, polyacrylic acid, polymethacrylic acid and salts thereof and the like It has been proposed to provide a water-soluble polymer recording layer, but even if the conventional recording layer satisfies the ink absorbency, the water resistance is poor, and the recording layer or the recording portion dissolves in water and a recorded image is formed. Disappears, the surface becomes sticky, the recorded image bleeds, and blocking occurs when sheets are laminated.

SUMMARY OF THE INVENTION An object of the present invention is to solve such a problem and to provide a recording sheet which is excellent in ink absorbency and excellent in water resistance and moisture resistance.

[0007]

According to the present invention, there is provided a recording sheet comprising a substrate having an ink receiving layer provided on at least one surface of a base material, wherein the ink receiving layer has a gel fraction per one minute of water immersion. Is 50% or more.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As a substrate, paper, synthetic paper, plastic film and the like are used. Among them, a plastic film is preferable from the viewpoint of water resistance and moisture resistance.

The plastic film may be made of polyester, polyolefin, polyamide, polyesteramide, polyether, polyimide, polyamideimide, polystyrene, polycarbonate, poly-ρ-phenylene sulfide, polyetherester, polyvinyl chloride, poly (meth). Acrylic esters are preferred. Further, these copolymers, blends, and further cross-linked ones can also be used.

Further, among the above plastic films, polyester, for example, polyethylene terephthalate,
Polyethylene 2,6-naphthalate, polyethylene α,
β-bis (2-chlorophenoxy) ethane 4,4′-dicarboxylate, polybutylene terephthalate and the like. Among them, mechanical properties, workability and other qualities, economic efficiency, etc. Polyethylene terephthalate and polyethylene 2,6-naphthalate are preferred.

The polyester in the present invention is specifically, for example, terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, bis-α, β (2-chlorophenoxy)
At least one of bifunctional carboxylic acids such as ethane 4,4'-dicarboxylic acid, adipic acid, and sebacic acid and at least one of glycols such as ethylene glycol, triethylene glycol, tetramethylene glycol, hexamethylene glycol, and decamethylene glycol. A polyester obtained by polycondensing with a seed can be used.
In addition, the polyester may be blended or copolymerized with various kinds of polymers as long as the object of the present invention is not impaired, and may include an antioxidant, a heat stabilizer, a lubricant, a pigment, an ultraviolet absorber and the like. It may be. The intrinsic viscosity (measured in orthochlorophenol at 25 ° C.) of the polyester is usually 0.1.
It is selected from the range of 4 to 2, preferably 0.5 to 1.

The polyester film used in the present invention comprises:
It is also possible to use those whitened by incorporating white inorganic particles into the polyester.

[0013] The white inorganic particles refer to inorganic particles which are almost uncolored, and include calcium carbonate, amorphous zeolite particles, anatase type titanium dioxide, calcium phosphate, calcium sulfate, barium sulfate, silica, alumina, kaolin,
Talc, clay and the like are used. In addition to such inorganic particles, fine particles precipitated by a reaction between a catalyst residue and a phosphorus compound in a polyester polymerization reaction system can also be used.

Further, it is also possible to use a film in which fine bubbles are contained inside the film and whitened by scattering light with the bubbles. The formation of these fine bubbles is caused by the incompatibility of polymers such as poly-3-methylbutene-1, poly-4 in the film matrix, such as polyester.
-Methylpentene-1, polypropylene, polyvinyl-
Finely disperse t-butane, 1,4-trans-poly-2,3-dimethylbutadiene, cellulose triacetate, cellulose tripropionate, polychlorotrifluoroethylene, etc. It is formed by stretching uniaxially or biaxially. Upon stretching, voids (bubbles) are formed around the immiscible polymer particles, which exhibit a light scattering action and are whitened. In addition, since it has fine bubbles, its specific gravity is low, and it also has cushioning properties, so that a clear image can be obtained.

When such a cell-containing polyester film is used, the apparent specific gravity of the cell-containing polyester film is desirably 0.4 or more and 1.3 or less, preferably 0.6 or more and 1.2 or less. If the apparent specific gravity is lower than the above range, mechanical properties and thermal dimensional stability are inferior, which is not preferable.

If the polyester film has been subjected to a surface treatment, that is, a film subjected to a corona discharge treatment (in air, nitrogen, carbon dioxide, etc.) or an easy adhesion treatment, the adhesion to the recording layer, the water resistance, and the water resistance It is more preferably used because its solvent properties and the like are improved. Various methods can be used for the easy adhesion treatment.Acrylic, urethane, polyester-based adhesives or the like applied in the film manufacturing process, or the film after uniaxial or biaxial stretching as described above. Those coated with various adhesives can be suitably used.

The base film may be a transparent film or a colored film.

The thickness of the substrate is not particularly limited, but is usually 10 μm or more and 500 μm or less, preferably 20 μm or more and 300 μm or less, more preferably 30 μm or more and 250 μm or less.
It is desirable that it is not more than μm.

As the crosslinked polyalkylene oxide resin in the present invention, a resin composition and the like described in JP-A-8-12871 can be effectively used.

As the cationic copolymer in the present invention, for example, a copolymer of a quaternary ammonium salt with styrene or an acrylic ester is used. As used herein, the acrylic ester refers to an acrylic ester and a methacrylic ester, and is preferably an ester of a fatty acid alcohol. For example, methyl acrylate, ethyl acrylate, butyl acrylate, propyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, propyl methacrylate, 2-hydroxylethyl methacrylate, 2-hydroxylethyl acrylate and the like are used. Among them, a cationic copolymer having a polyorganosiloxane unit is preferably used.

The cationic copolymer having a polyorganosiloxane unit has a general formula

Embedded image (Wherein, R may be the same or different. C 1-10
Represents an alkyl group or a phenyl group, and n represents an integer of 5 or more. ) Is a cationic copolymer having a polyorganosiloxane unit.

Specific examples of the cationic monomer copolymerized with the polyorganosiloxane unit include (meth) acryloyloxytrimethylammonium chloride, (meth) acryloyloxyhydroxypropyltrimethylammonium chloride, and (meth) acryloyl. (Meth) acrylic monomers such as oxytriethylammonium chloride, (meth) acryloyloxydimethylbenzylammonium chloride, (meth) acryloyloxytrimethylammonium methyl sulfate, (meth) acrylamidopropyltrimethylammonium chloride, (meth) acrylamidopropyldimethyl (Meth) acrylamide-based cationic monomers such as benzylammonium chloride are used.

Further, in order to improve the water resistance, it is preferable to copolymerize various alkyl (meth) acrylates, styrene, vinyl esters such as vinyl acetate and the like.

The colloidal silica in the present invention is a colloidal dispersion in which ultrafine silica particles are stably dispersed in water or a solvent. There are various methods for producing such colloidal silica, and a method using an ion exchange resin is generally used. Usually, these colloidal silicas have sufficient anionicity to cause each particle to repel each other.

The ionicity of the colloidal silica used in the present invention is desirably cationic. The cationic colloidal silica is obtained by reacting a mixture of a polyvalent metal ion such as aluminum ion with silica, and is a material in which at least the surface of the silica particles is cationically charged. When the ionicity of the colloidal silica is cationic, it is preferably used because the dye fixability in the ink is improved.

The hydrophilic resin used in the present invention includes:
Ethylene-vinyl acetate copolymer resin, ionomer resin,
Polyester resin, urethane resin, nylon resin, ethylene-acrylic acid copolymer resin, ethylene-ethyl acrylate copolymer resin, ethylene-methyl acrylate copolymer resin, ethylene-methacrylic acid copolymer resin, ethylene-vinyl alcohol copolymer resin , A polyvinyl alcohol resin, a polyvinyl butyral resin, a polystyrene resin, or the like, but is not limited thereto.

In the present invention, the gel fraction of the receptor layer per one minute of immersion in water is preferably 50% or more, more preferably 60% or more, and further preferably 80% or more. If the gel fraction is lower than 50%, the printed image will flow and it will be difficult to see, which is not preferable.

In addition, the receiving layer has a lower layer mainly composed of a cationic copolymer and a cross-linked polyalkylene oxide resin and an upper layer mainly composed of a hydrophilic polymer resin. Preferably, the thickness d1 of the lower layer mainly composed of the cationic copolymer and the crosslinked polyalkylene oxide resin and the thickness d1 of the upper layer mainly composed of the hydrophilic polymer resin
2 preferably satisfies d1 ≧ d2. When d2 exceeds d1, water resistance and moisture resistance decrease, which is not preferable.

Although the coating thickness of the receiving layer is not particularly limited,
It is 1 to 50 μm, preferably 2 to 30 μm. If the thickness is smaller than this, the ink absorbability of the obtained recording layer is inferior. If the thickness is larger than this, workability deteriorates and blocking tends to occur, which is not preferable.

In the present invention, when used as a recording sheet, it is preferable to impart an antistatic function from the viewpoint of adhesion of dust and the like due to static electricity and running properties. In order to impart antistatic properties, it is desirable to provide a receiving layer on one side of the substrate and provide an antistatic layer on the other side, or add an antistatic agent to the receiving layer.

The antistatic layer referred to in the present invention includes a coating layer made of an antistatic agent, a resin layer containing an antistatic agent, and a vapor-deposited layer made of a metal or metal oxide. Agent, conductive polymer, conductive carbon fine particles,
Metal or metal oxide fine particles are used.

In the present invention, an antistatic agent is applied to the surface of the substrate opposite to the receptor layer, or a coating agent containing inorganic or organic fine particles is applied in order to improve the running property and heavy running property of the recording sheet. May be.

The surface resistance of the antistatic layer opposite to the receptor layer of the present invention is preferably from 10 ⁵ to 10 ¹³ Ω / □.

In the present invention, inorganic and / or organic particles may be dispersed in the receiving layer or the antistatic layer in order to further enhance the recording characteristics. As the inorganic particles, for example, silica, clay, talc, diatomaceous earth, calcium carbonate, barium sulfate, aluminum silicate, synthetic zeolite, alumina, zinc oxide, mica and the like are used. As the organic particles, for example, polymethyl methacrylate, polystyrene,
Plastic pigments such as copolymers thereof, polyvinyl chloride, polyethylene, polypropylene, polyvinylidene chloride, and polycarbonate can be preferably used, but are not limited thereto.

In the receiving layer of the recording sheet according to the present invention,
Various additives within a range that does not impair the properties of the present invention, such as silicones, fluorine-based leveling agents, defoamers, thickeners,
It may contain an antistatic agent, an antioxidant, an ultraviolet inhibitor, a dye and the like.

The method for applying the recording layer is not particularly limited,
Gravure coating, reverse coating, kiss coating,
Methods such as a die coating method and a bar coating method can be used. At this time, not only the coatability is improved by applying a surface treatment such as a corona discharge treatment or a primer treatment in the air or other atmosphere as necessary before coating on the film, The receiving layer can be more firmly formed on the film. In addition, the coating agent concentration,
The conditions for drying the coating film are not particularly limited, but the drying conditions for the coating film are desirably performed within a range that does not adversely affect the properties of the substrate.

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a method for evaluating various characteristics according to the present invention will be described.

(1) Gel Fraction of Receiving Layer The recording sheet was cut into 10 cm × 10 cm and weighed (A).
Is measured. Next, immerse in water for 1 minute, dry and weigh (B)
Is measured. Next, the receiving layer was completely peeled off, the weight (C) of the substrate alone was measured, and the dissolution rate was calculated by the following equation.

Gel fraction (%) = [(BC) / (AC)] × 100

(2) Inkjet recording properties "98no" personal computer manufactured by NEC Corporation
te ”bubble jet printer B manufactured by Canon Inc.
JC-820J was connected, and a character / photograph image was inkjet-printed, the image quality and ink absorbability were evaluated, and the printability was determined as follows. The image quality was evaluated by visual observation using a magnifying glass, and the ink absorptivity was evaluated based on the degree of contamination of the recording layer with ink when the recording portion was rubbed once with a finger immediately after recording.

Image quality ：: very good (dots are uniform and clear) ：: good △: slightly poor ×: dot flow, repelling, bleeding, etc. Ink absorbency ：: very good (recording layer is completely dirty)な い: good △: slightly poor ×: ink removed, recording layer stained

(3) Water resistance of recorded image The recording sheet on which ink jet recording was performed was immersed in water for 1 minute, and the degree of image flow was evaluated.

：: Image does not flow at all Δ: Image flows slightly ×: Image flows

(4) Moisture resistance of the recorded image The recording sheet on which the ink jet recording was performed was subjected to 40 ° C./80% R
The sample was allowed to stand in an atmosphere of H for one day, and the degree of image bleeding was evaluated.

：: Image does not blur at all Δ: Image slightly blurs ×: Image blurs

(5) Surface resistance value ULTRA HIGH RESISTANCE MET
Using ER (“ADVANTEST” R8340)
20 ° C., 60 ° C. under the conditions of a voltage of 100 V and a Carge of 5 seconds.
% RH was measured.

(6) Specific Gravity The film was cut into a 100 × 100 mm square, and at least 10 pieces were mounted on a dial gauge (No. 2109-10, manufactured by Mitoyo Seisakusho Co., Ltd.) with a measuring element (No. 7002) having a diameter of 10 mm. The thickness of the point was measured and the average value of the thickness d (μ
m) is calculated. The film is weighed by a direct balance and the weight w (g) is read to the unit of 10 ^-4 g. At this time, the specific gravity was set to w / d × 100.

[0047]

Next, the present invention will be described in more detail with reference to Examples, but it should not be construed that the invention is limited thereto.

Example 1 A homopolymer chip of polyethylene terephthalate produced by a conventional method (intrinsic viscosity: 0.62, melting point: 25)
9 [deg.] C.) to obtain a biaxially oriented polyester film having a thickness of 100 [mu] m and a specific gravity of 1.4 by a conventional method. Corona discharge treatment was performed on the polyester film thus obtained. Next, the following composition was used as the receiving layer on the corona-discharge treated surface, applied with a reverse coater so that the thickness after drying was 20 μm, and dried at 120 ° C. for 2 minutes to obtain a recording sheet of the present invention. . The gel fraction of the receiving layer of the recording sheet thus obtained was as high as 95.8%,
The characteristics are as shown in Table 1, and the recording properties are good, water resistance,
The moisture resistance was also excellent. Further, when projected by an overhead projector, the image was clear and good as a sheet for an overhead projector.

[Coating composition] Methyl methacrylate 45
Part, a methacryloxyethyltrimethylammonium chloride, 45 parts, a cationic copolymer having a polyorganosiloxane unit consisting of 10 parts of one end methacryloxy-modified polyorganosiloxane and a crosslinked polyalkylene oxide resin (manufactured by Sumitomo Seika Co., Ltd. Coke ”) and melamine resin (“ Nikarac ”M, manufactured by Sanwa Chemical Co., Ltd.)
W12LF) in water / water so that the solid content ratio is 4/5/1.
IPA was dissolved in 1/1 solvent to obtain a solution having a solid content of 15%.

Example 2 In Example 1, a cationic copolymer ("Saftomer" ST2100 manufactured by Mitsubishi Chemical Corporation) and a crosslinked polyalkylene oxide resin ("Aqua Coke" manufactured by Sumitomo Seika Co., Ltd.) were used as the receiving layer composition. And butyral resin ("Eslec" manufactured by Sekisui Chemical Co., Ltd.) was dissolved in a water / IPA = 1/1 solvent so as to have a solid content ratio of 5/4/1 to obtain a solution having a solid content of 15%. Similarly, a recording sheet of the present invention was obtained. The gel fraction of the receiving layer of the recording sheet thus obtained was 94.
The properties were as high as 5%, and the characteristics were as shown in Table 1. The recording properties were good, and the water resistance and moisture resistance were excellent. Further, when projected by an overhead projector, the image was clear and good as a sheet for an overhead projector.

Example 3 Polyethylene Terephthalate Chip and Molecular Weight 40
After the master chip to which polyethylene glycol of No. 00 was added at the time of polymerization of polyethylene terephthalate was vacuum-dried at 180 ° C., it was mixed so as to be 89% by weight of polyethylene terephthalate, 1% by weight of polyethylene glycol, and 10% by weight of polymethylpentene. 300
Feed to extruder B heated to ° C. Further, after drying polyethylene terephthalate containing 10% by weight of calcium carbonate having an average particle diameter of 1.0 μm as described above,
Feed to extruder A. The polymers extruded from the extruders A and B were laminated so as to have a three-layer configuration of A / B / A, and formed into a sheet from a T die. Further, the unstretched film cooled and solidified by a cooling drum having a surface temperature of 25 ° C. was led to a group of rolls heated to 85 to 95 ° C., stretched 3.4 times in the longitudinal direction, and cooled by a group of rolls of 25 ° C.

Subsequently, the longitudinally stretched film was guided to a tenter while gripping both ends of the film with clips, and stretched 3.6 times in a direction perpendicular to the longitudinal direction in an atmosphere heated to 130 ° C. Thereafter, heat fixing at 230 ° C. was performed in a tenter, and after uniform cooling, the film was cooled to room temperature and wound up to obtain a white film having a thickness of 100 μm and a specific gravity of 1.0. The laminated structure of the film was 5/90/5 μm. The receiving layer coating composition used in Example 1 was applied as a lower layer composition of the receiving layer on the polyester film obtained by the above method using a reverse coater so that the thickness after drying became 10 μm, and dried at 120 ° C. for 2 minutes. I let it. Further, as the upper layer composition of the receiving layer, a cation-modified PVA (CM-318 manufactured by Kuraray Co., Ltd.) is dissolved in a solvent of water / methanol = 1/1 to form a solution having a solid content of 10%, and the thickness after drying is 1 μm. It was applied with a gravure coater and dried at 120 ° C. for 1 minute to obtain a recording sheet of the present invention. The gel fraction of the receiving layer of the recording sheet thus obtained was as high as 93.5%, and the characteristics were as shown in Table 1. The recording properties were good, and the water resistance and moisture resistance were excellent. .

Example 4 A recording sheet of the present invention was obtained in the same manner as in Example 3, except that PVA ("Denkapovar" W-24, manufactured by Denki Kagaku KK) was used as the upper layer composition of the receiving layer. The gel fraction of the receiving layer of the recording sheet thus obtained was as high as 94.2%, and the characteristics were as shown in Table 1. The recording performance was good, and the water resistance and moisture resistance were excellent. Was.

Example 5 In Example 3, the composition of the upper layer of the receiving layer was PVA (“DENKAPOVAL” W-24, manufactured by Denki Kagaku Co., Ltd.) and an anionic polystyrene resin (“Chemistat 6120”, manufactured by Sanyo Chemical Co., Ltd.). A recording sheet of the present invention was obtained in the same manner except that a solid content ratio of 6/4 was used. The dissolution rate of the receiving layer of the recording sheet thus obtained was as high as 93.7%.
The characteristics are as shown in Table 1, and the recording properties are good, water resistance,
The moisture resistance was also excellent.

Example 6 A homopolymer chip of polyethylene 2,6-naphthalate produced by a conventional method (intrinsic viscosity [η] = 0.7)
After sufficiently dried in a vacuum, fed to an extruder, melt-extruded at 295 ° C., filtered through a 10 μm-cut metal sintering filter, extruded into a sheet shape from a T-shaped die, and cooled to a cooling drum having a surface temperature of 50 ° C. It was cooled and solidified. In order to improve the adhesion between the sheet and the surface of the cooling drum during this time, a wire electrode was arranged on the sheet side, and a DC voltage of 6000 V was applied. The unstretched polyethylene 2,6-naphthalate film thus obtained was stretched 4.5 times in the longitudinal direction with a group of rolls heated to 120 ° C, and cooled to 25 ° C to obtain a uniaxially stretched film.

Further, the stretched film was guided to a tenter, stretched 4.3 times in the width direction in an atmosphere maintained at 125 ° C., heat-fixed at 225 ° C., and biaxial with a thickness of 75 μm and a specific gravity of 1.35. A stretched film was obtained. The film thus obtained was subjected to a corona discharge treatment, and a recording sheet of the present invention was obtained on the treated surface in the same manner as in Example 1. The dissolution rate of the receiving layer of the recording sheet thus obtained was as high as 95.7%, and the characteristics were as shown in Table 1. The recording property was good, and the water resistance and the moisture resistance were excellent.

Further, it has been found that since the biaxially stretched polyethylene 2,6-naphthalate film is used as the substrate, the heat resistance is excellent.

Comparative Example 1 PVA (PVA12 manufactured by Kuraray Co., Ltd.) was used as the receiving layer composition.
A recording sheet was obtained in the same manner as in Example 1 except that 4) was used. The dissolution rate of the receiving layer of the recording sheet was as low as 25.2%, and the characteristics were as shown in Table 1. The recording properties, water resistance, and moisture resistance were poor.

Comparative Example 2 A recording sheet was obtained in the same manner as in Example 1 except that a butyral resin ("Surec" manufactured by Sekisui Chemical Co., Ltd.) was used as the receiving layer composition. The dissolution rate of the recording sheet is 31.4%
And the properties are as shown in Table 1, recording properties, water resistance,
It was inferior in moisture resistance.

[0060]

[Table 1]

[0061]

The recording sheet of the present invention has excellent ink absorbency, printability, image quality, water resistance and moisture resistance, and is particularly preferably used as a recording sheet for a color ink jet printer. Further, it can be preferably used in electrophotographic copying machines, fabric ink receivers, carbon ink receivers, heat-sensitive ink receivers including sublimation types, and applications such as offset printing and flexographic printing.

Claims (13)

[Claims] 1. A recording sheet comprising an ink receiving layer provided on at least one side of a substrate, wherein the ink receiving layer has a gel fraction of 50% or more in one minute of water immersion. 2. The recording sheet according to claim 1, wherein the ink receiving layer contains a crosslinked polyalkylene oxide resin. 3. The recording sheet according to claim 1, wherein the ink receiving layer contains a cationic copolymer and a crosslinked polyalkylene oxide resin as main components. 4. The recording sheet according to claim 1, wherein the ink receiving layer mainly comprises a cationic copolymer, a crosslinked polyalkylene oxide resin, and a hydrophilic polymer resin. 5. The recording sheet according to claim 1, wherein the ink receiving layer contains a cationic copolymer, a crosslinked polyalkylene oxide resin, a hydrophilic polymer resin and colloidal silica as main components. 6. A recording sheet comprising an ink receiving layer provided on at least one side of a base material, wherein the ink receiving layer comprises a lower layer mainly composed of a cationic copolymer and a crosslinked polyalkylene oxide resin, and a hydrophilic polymer. The recording sheet according to claim 1, comprising an upper layer mainly composed of a resin. 7. The thickness d1 of a lower layer mainly composed of a cationic copolymer and a cross-linked polyalkylene oxide resin, and the thickness d of an upper layer mainly composed of a hydrophilic polymer resin.
7. The recording sheet according to claim 1, wherein d2 satisfies d1 ≧ d2. 8. The recording sheet according to claim 3, wherein the cationic copolymer is a cationic copolymer having a polyorganosiloxane unit. 9. The recording sheet according to claim 1, wherein the substrate is a polyester film. 10. The recording sheet according to claim 9, wherein the substrate is a white polyester film. 11. The recording sheet according to claim 10, wherein the base material is a white polyester film having an apparent specific gravity of 0.4 or more and 1.3 or less. 12. The recording sheet according to claim 1, wherein the base material is polyethylene 2,6-naphthalate. 13. The recording sheet according to claim 1, wherein the recording sheet is for inkjet recording.