JPH11138979A - Recording sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a recording sheet having a good ink absorbability, printability and image quality and an excellent water resistance and moisture resistance. SOLUTION: In the recording sheet comprising an ink receptive layer provided at least on one side surface of a base material, the layer has a layer containing a polyvinyl alcohol and a cationic polymer resin. The polyvinyl alcohol has a degree of saponification of 25 to 60 mol.%. And, the polymer resin has a -COOH group. The receptive layer may contain the polyvinyl alcohol having a degree of saponification of 25 to 60 mol.%, a polyvinylpyrrolidone and the polymer resin.

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. Specifically, in ink jet recording, it has excellent ink absorption, good color recording is possible, high image density, clear image color tone, good color development (gloss), and excellent water resistance and moisture resistance. Regarding the recording sheet.

[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. In particular, an ink-jet printer uses ink that is difficult to dry in order to prevent clogging of nozzles, and the component of this ink is generally one in which a binder, a dye, a solvent, an additive, and the like are dissolved in water. Therefore, it is necessary to use a recording sheet having good water absorbency, and special paper having good ink absorbency is usually used.

[0003]

In general, paper is a color which is inferior in water resistance and moisture resistance, and if plastic films which do not have these disadvantages can be applied, the advantages can be utilized in various fields.

When a sheet having low ink absorbency is used for recording by an ink jet printer, the ink may be insufficiently dried or may not be dried at all. If the finger is rubbed or overlapped, the recorded 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.

[0006]

According to the present invention, there is provided a recording sheet comprising a substrate having an ink receiving layer provided on at least one side of a substrate, wherein the ink receiving layer is formed of polyvinyl alcohol and a cationic polymer. It is characterized by containing a resin.

As the substrate, paper, cloth, synthetic paper, plastic film, paper / plastic film, cloth / plastic film and the like are used. Among them, a water-resistant and moisture-resistant point color plastic film is preferable. Examples of the material of the plastic film include polyester, polyolefin, polyamide, polyester amide, polyether, polyimide, polyamide imide, polystyrene, polycarbonate, poly-ρ-phenylene sulfide, polyether ester, polyvinyl chloride, and poly (meth) acrylate. Is 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 a well-known polyester, specifically, for example, terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, bis-α, β (2-chlorophenoxy) ethane 4,4′-dicarboxylic acid, Obtained by polycondensing at least one kind of bifunctional carboxylic acid such as adipic acid and sebacic acid and at least one kind of glycol such as ethylene glycol, triethylene glycol, tetramethylene glycol, hexamethylene glycol, and decamethylene glycol. Polyester can be mentioned. 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 of the polyester (measured in orthochlorophenol at 25 ° C) is generally 0.4 to 2.0, preferably 0.5 to 2.0.
A color range of 1.0 is selected.

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.

[0011] The white inorganic particles refer to inorganic particles that 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. 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, or the like, or add the above whitening fine particles and mix them. 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 preferably 0.4 or more and 1.3 or less, more 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, in nitrogen, in carbon dioxide gas, etc.) or an easy adhesion treatment, adhesion to the recording layer, water resistance, and 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 substrate 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.

Further, when the substrate is a paper / plastic film or a cloth / plastic film, it is preferable from the viewpoint of texture, and since the plastic film can be made thin, it is advantageous in terms of cost and is therefore preferable.

The polyvinyl alcohol used in the present invention is produced by a known production technique by hydrolysis of polyvinyl acetate, but the production method is not limited at all.

The degree of saponification of polyvinyl alcohol is 25 m
ol to 60 mol% is preferable, and 30 to 50 mol% is more preferable.

The degree of saponification of polyvinyl alcohol is 25 m
If the amount is less than 60 mol%, the ink absorbency becomes poor.
Exceeding the range is not preferred because the water resistance decreases.

Examples of the cationic polymer resin in the present invention include a copolymer of a quaternary ammonium salt with styrene or an acrylic acid ester. 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,
Examples thereof include propyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, propyl methacrylate, 2-hydroxylethyl methacrylate, and 2-hydroxylethyl acrylate. Specific examples of the cationic monomer include (meth) acryloyloxy-trimethylammonium chloride, (meth) acryloyloxyhydroxypropyltrimethylammonium chloride, (meth) acryloyloxy-triethylammonium chloride, and (meth) acryloyloxydimethylbenzyl. (Meth) acrylic monomers such as ammonium chloride and (meth) acryloyloxy-trimethylammonium methyl sulfate; (meth) acrylamides such as (meth) acrylamidopropyltrimethylammonium chloride and (meth) acrylamidopropyldimethylbenzylammonium chloride Series cationic monomers.

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.
Among the cationic polymer resins, those having a -COOH group are preferred because they improve water resistance and adhesion.

In the present invention, in order to improve the water resistance of the receptor layer, it is preferable to use a curing agent such as melamine, epoxy, isocyanate, oxazoline compound and zirconium compound.
It is more preferable than the color such as the stability of the coating liquid.

Further, in the present invention, the leveling property of the receptor layer,
It is preferable to use a fluorinated surfactant in order to improve the dyeing properties of the ink. Examples of the fluorine surfactant include perfluoroalkyl sulfonates, perfluoroalkyl carboxylate salts, perfluoroalkyl ethylene oxide adducts, perfluoroalkyltrimethylammonium salts, perfluoroalkylamino sulfonate and other perfluoroalkyl group-containing fluorine-based surfactants. Examples include, but are not limited to, surfactants. Among them, a perfluoroalkylethylene oxide adduct is preferable because of its excellent solubility in various solvents, low foaming property, surface tension lowering ability and the like.

Other hydrophilic resins can be mixed in the receiving layer of the present invention, if necessary. As the hydrophilic resin,
Ethylene-vinyl acetate copolymer resin, ionomer 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, polyvinyl Examples thereof include butyral resin, polystyrene resin, polyalkylene oxide resin, and gelatin, but are not limited thereto.

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 a function of preventing adhesion of dust and the like due to static electricity and a point color electrification of 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 in the present invention includes a coating layer of an antistatic agent color, a resin layer containing an antistatic agent, a vapor deposited layer of a metal or metal oxide color, and the like. Agent, conductive polymer, conductive carbon fine particles, metal or metal oxide fine particles, and the like.

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. You may.

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. Examples of the inorganic particles include silica, clay, talc, diatomaceous earth, calcium carbonate, barium sulfate, aluminum silicate, synthetic zeolite, alumina, zinc oxide, and mica. 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 such as a silicone-based leveling agent, an antifoaming agent, a thickener, an antistatic agent, an antioxidant, an ultraviolet inhibitor, a fluorescent brightener, a dye, etc., within a range not impairing the characteristics of the present invention. May be included.

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.

[0033]

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

(1) Inkjet recording properties Inkjet printer PM700 manufactured by Epson Corporation
Using C, a solid image and a photographic image were inkjet-recorded, the image quality and the ink absorbency were evaluated, and the recordability 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 absorption ◎: very good (recording layer is completely dirty) ○: good △: slightly poor ×: ink is removed and the recording layer is stained (2) Water resistance of the 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 X: Image flows (3) Moisture resistance of recorded image A recording sheet on which ink-jet recording was performed was heated at 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.

：: The image does not blur at all. Δ: The image blurs slightly. X: The image blurs. (4) Specific gravity The film is cut into a 100 × 100 mm square, and the diameter is 10 m in a dial gauge (No. 2109-10 manufactured by Mitoyo Seisakusho).
The thickness of at least 10 points is measured with a probe attached with an m measuring element (No. 7002), and the average value d (μm) of the thickness 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.

Next, the present invention will be described in 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 stretched 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, as a receiving layer on the corona discharge treated surface, polyvinyl alcohol (LM-15, manufactured by Kuraray Co., Ltd.) and cationic acrylic resin (Dulima-SPO-602, manufactured by Nippon Pure Chemical Co., Ltd.) of 35 mol% saponification were used. A zirconium-based curing agent (Zircozol ZC-2, Daiichi Kagaku Kagaku Kogyo Co., Ltd.) was dissolved in a water / methanol = 2/1 solvent so that the solid content ratio was 100/100/3, and the solid content was A 30% solution was prepared, applied by a reverse coater so that the thickness after drying became 15 μm, and dried at 120 ° C. for 1 minute to obtain a recording sheet of the present invention. The recording characteristics of the recording sheet thus obtained were as shown in Table 1, and the recording sheet was excellent and had excellent water resistance and moisture resistance. Also,
When projected by an overhead projector, the image was clear and good as a sheet for an overhead projector.

Example 2 In Example 1, as a receiving layer, polyvinyl alcohol having a saponification ratio of 35 mol% (LM-15 manufactured by Kuraray Co., Ltd.) was used.
And cationic acrylic resin (Julima-SPO-602 manufactured by Nippon Pure Chemical Co., Ltd.) and polyvinylpyrrolidone (BASF
(Rubiscol K-90) and zirconium-based curing agent (Zircosol ZC-, Daiichi Kazoku Kagaku Kogyo Co., Ltd.)
2) Solvent was dissolved in water / methanol = 2/1 so that the solid content ratio was 100/100/50/5, and the solid content was 30%.
The recording sheet of the present invention was obtained in the same manner except that the solution was applied as a solution.

The recording properties of the recording sheet thus obtained were as shown in Table 1, and the recording sheet was excellent, and had excellent water resistance and moisture resistance. 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
The master chip to which the polyethylene glycol of No. 00 was added at the time of polymerization of polyethylene terephthalate was vacuum-dried at 180 ° C., and then 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 holding 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. A recording sheet was obtained on the polyester film obtained by the above method as a receiving layer in the same manner as in Example 2. The recording characteristics of the recording sheet thus obtained are as shown in Table 1, and the recording properties are good.
The water resistance and moisture resistance were also excellent.

Example 4 In Example 1, as a receiving layer, polyvinyl alcohol containing 35 mol% of saponification (LM-15, manufactured by Kuraray Co., Ltd.) was used.
And cationic acrylic resin (Julima-SPO-602 manufactured by Nippon Pure Chemical Co., Ltd.) and polyvinylpyrrolidone (BASF
Rubiscol K-90) and a fluorine-based surfactant (Megafac F-142 manufactured by Dainippon Ink and Chemicals, Inc.)
D) and a zirconium-based curing agent (Zircosol ZC-2, Daiichi Kagaku Kagaku Kogyo KK) in a solid content ratio of 100 /
Water / methanol = 2 so as to be 50/100/1/5
/ 1 solvent to obtain a recording sheet of the present invention in the same manner except that the solution was applied as a solution having a solid content of 30%.

The recording characteristics of the recording sheet thus obtained were as shown in Table 1, and the recording sheet was excellent and had excellent water resistance and moisture resistance. Further, when projected by an overhead projector, the image was clear and good as a sheet for an overhead projector.

Comparative Example 1 In Example 1, 35 mol% of saponified was used as the receiving layer.
Polyvinyl alcohol (LM-1 manufactured by Kuraray Co., Ltd.)
A recording sheet was obtained in the same manner except that 5) was not included. The recording characteristics of the recording sheet thus obtained were as shown in Table 2, and were poor in image quality and ink absorption. Comparative Example 2 A recording sheet was obtained in the same manner as in Example 1 except that the receiving layer did not contain a cationic acrylic resin (Julima-SPO-602 manufactured by Nippon Pure Chemical Industries, Ltd.). The recording characteristics of the recording sheet thus obtained are as shown in Table 2,
The image quality and the ink absorption were poor.

Tables 1 and 2 below summarize the results of the above Examples and Comparative Examples, respectively.

[0048]

[Table 1]

[Table 2]

[0049]

As described above, the recording sheet according to the present invention is a recording sheet having an ink receiving layer provided on at least one surface of a substrate, wherein the ink receiving layer has a polyvinyl alcohol and a cationic polymer resin. , Which has excellent ink absorbency, printability, image quality, water resistance, and moisture resistance, and can be particularly preferably used as a recording sheet for a color inkjet printer.

Further, it can be preferably used in applications such as electrophotographic copying machines, fabric ink receivers, carbon ink receivers, heat-sensitive ink receivers including sublimation types, offset printing, and flexographic printing.

Claims (13)

[Claims] 1. A recording sheet comprising an ink receiving layer provided on at least one surface of a substrate, wherein the ink receiving layer contains polyvinyl alcohol and a cationic polymer resin. 2. Polyvinyl alcohol having a saponification degree of 25 to 6
The recording sheet according to claim 1, wherein the recording sheet is 0 mol% of polyvinyl alcohol. 3. A recording sheet having an ink receiving layer provided on at least one surface of a substrate, wherein the ink receiving layer contains polyvinyl alcohol having a saponification degree of 25 to 60 mol%, polyvinyl pyrrolidone, and a cationic polymer resin. A recording sheet, characterized in that: 4. The recording sheet according to claim 1, wherein the cationic polymer resin has a —COOH group. 5. The recording sheet according to claim 1, wherein said ink receiving layer contains at least one color selected from melamine, epoxy, isocyanate, oxazoline and zirconium-based curing agents. . 6. The recording sheet according to claim 1, wherein said ink receiving layer contains a fluorine-containing surfactant. 7. The recording sheet according to claim 1, wherein said fluorosurfactant is a perfluoroalkylethylene oxide adduct. 8. The recording sheet according to claim 1, wherein the substrate is a polyester film. 9. The recording sheet according to claim 1, wherein the substrate is a white polyester film. 10. The recording sheet according to claim 1, wherein the base material is a white polyester film having an apparent specific gravity of 0.4 or more and 1.3 or less. 11. The recording sheet according to claim 1, wherein the base material is polyethylene 2,6-naphthalate. 12. The recording sheet according to claim 1, wherein the substrate is a paper / plastic film or a cloth / plastic film. 13. The recording sheet according to claim 1, wherein the recording sheet is for ink jet recording.