JPH0999637A - Recording sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a recording sheet high in the adhesiveness of an ink receiving layer and a base material, excellent in ink absorbability, high in ink drying properties and generating no curl in use environment, that is, excellent in curl resistance. SOLUTION: In a recording sheet 1 wherein an ink receiving layer is provided on at least the single surface of a base material sheet 2, the ink receiving layer 3 consists of a water-soluble resin and a hydrophilic resin with Tg of -100-50 deg.C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is excellent in sharpness of an image without peeling of the ink receiving layer and protrusion of the ink receiving layer during ink absorption, that is, slow drying of the ink in the ink receiving layer. The present invention relates to an inkjet recording sheet.

[0002]

2. Description of the Related Art Conventionally, as an output print of a computer or a word processor, a wire dot recording system,
Various systems such as a thermosensitive coloring recording system, a thermosensitive transfer recording system, a thermosensitive sublimation transfer recording system, an electrophotographic recording system, and an ink jet recording system have been developed. Among them, the ink jet recording method is characterized in that plain paper can be used as a recording sheet, the printing cost is low, the apparatus is compact and there is no noise, and high speed recording is possible. For this reason, attention has been paid to the use as a printer for quickly and accurately outputting image information such as characters and figures produced by a computer or the like. Also,
Since it is easy to colorize and the picture is clear, there is also a request to record image information produced by a computer on a transparent recording sheet with an inkjet printer and use it as a manuscript such as OHP at conferences and various academic conference presentations. It is rising.

In general, an ink jet printer ejects recording ink from a nozzle by pressure of a fine piezoelectric element (piezo element) or air pressure (bubble jet) generated by heating a thermal head, and adheres to a recording sheet. The recording is performed by causing the recording. For this reason, as a recording ink used for ink jet recording, an ink that is difficult to dry is used in order to prevent ink ejection failure from nozzles due to an increase in viscosity due to drying of the ink. In general, the ink component is generally a dye, resin, additive, etc. dissolved in water and alcohol. Therefore, a recording sheet on which recording is performed by an inkjet printer is required to absorb the liquid component of the attached ink and dry and solidify the ink.
For this reason, a recording sheet in which an ink receiving layer is formed on a base sheet to enhance ink absorption is used.

In particular, the ink receiving layer of a recording sheet for an ink jet printer is required to have the following characteristics. Drying property: Excellent ink absorbency and fast ink drying property. Image clarity: An appropriate dot spread is obtained, and a clear image without blur is obtained. Water resistance: The image does not blur or run out even if moisture adheres. Adhesion: The ink receiving layer does not easily peel off. Curling resistance: Curling does not occur in the recording sheet including the ink receiving layer in the use environment. From such a point of view, conventional recording sheets have an ink receiving layer on a base sheet, and as the receiving layer, one using a water-soluble resin, one using a hydrophilic resin, etc. have been devised. .

[0005]

However, although the ink receiving layer formed by coating a water-soluble resin such as polyvinyl alcohol or polyvinylpyrrolidone has high hydrophilicity and good image sharpness, the hydrophilicity of the resin is high. Therefore, there is a problem in that the adhesiveness to the plastic film used as the substrate is poor and the film is easily peeled off. Further, the ink receiving layer formed from the water-soluble resin contains a large number of hydrophilic groups, so that the dyeing of the water-soluble dye is good and the image clarity is good, but since the resin dissolves in water,
There is a problem that the recorded ink is easily sticky and the drying property is poor. Further, even in the ink receiving layer formed by applying a hydrophilic resin which is appropriately hydrophobized such as polyvinyl acetal, the adhesiveness with the plastic film used as the base material is poor, and it is hydrophilic but water-soluble. On the contrary, since it also has hydrophobicity, it has a problem that it is not well compatible with ink and image sharpness is poor.

The present invention was devised in view of the above circumstances, and has strong adhesion between the ink receiving layer and the base sheet, excellent ink absorbability, and quick ink drying property.
Further, it is an object of the present invention to provide a recording sheet that does not curl in the environment in which it is used, that is, has excellent curl resistance.

[0007]

In order to achieve the above object, the present invention provides a recording sheet in which an ink receiving layer is provided on at least one side of a substrate sheet, wherein the ink receiving layer comprises a water-soluble resin and Tg. Is composed of a hydrophilic resin having a temperature of -100 ° C to 50 ° C. Further, the ink receiving layer is characterized by using a polyvinyl resin as the water-soluble resin. Further, the substrate sheet is transparent.

The operation of the present invention is as follows. The water-soluble resin and Tg are -10 on at least one side of the base sheet.
By providing an ink receiving layer mainly composed of a hydrophilic resin of 0 ° C. to 50 ° C., it is a mixture of a resin having a Tg of −100 ° C. to 50 ° C. and a water-soluble resin. Stronger adhesion. Further, since the ink receiving layer is a mixture of a hydrophilic resin having a Tg of −100 ° C. to 50 ° C. and a water-soluble resin, not only the function as a primer layer but also the layer itself has ink absorbability. . Further, the ink receiving layer has a Tg of -100 ° C to 50 ° C.
Since it contains the above resin and has flexibility, curling does not occur in the usage environment. Therefore, the recording sheet of the present invention has excellent adhesiveness, ink drying properties, image clarity, and curl resistance.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing one embodiment of the recording sheet of the present invention. In FIG. 1, a recording sheet 1 is a base sheet 2
And an ink receiving layer 3 formed on one surface of the base sheet 2.

(Base Sheet) As the base sheet 2 used in the recording sheet of the present invention, the same base sheet as used in conventional recording sheets can be used as it is, and other base sheets can be used. Those can also be used and are not particularly limited. Synthetic paper such as polystyrene, fine paper, art paper, coated paper, cast coated paper, wallpaper,
Backing paper, synthetic resin impregnated paper, emulsion resin impregnated paper,
Examples include various colored or white papers such as synthetic rubber latex-impregnated papers, synthetic resin internal papers, paperboards, base materials for labels and plastic films. Further, a composite base material in which two or more of these materials are bonded together is also used. The thickness of these base material sheets is appropriately selected in consideration of strength and the like according to the application and is not particularly limited, but, for example, usually 5
It is about 0 to 200 μm.

The plastic film is preferably made of thermoplastic resin having heat resistance, dimensional stability and rigidity. For example, polyethylene terephthalate resin, polycarbonate resin, acrylic resin, polyvinyl chloride resin, polypropylene resin, polystyrene resin, polyvinyl alcohol resin, polyethylene resin,
The thickness of diacetate resin, triacetate resin, polyimide resin, etc. is about 5 to 250 μm, preferably 50 to 18 μm.
A film or plate having a thickness of about 0 μm may be used. In particular, when used for an overhead projector (OHP), a transparent substrate sheet is used even for these plastic films. Opaque plastic films and papers are used for applications that do not require transparency other than OHP applications. Further, one or both surfaces of the base sheet may be subjected to a corona discharge treatment or an easy adhesion treatment as necessary. Furthermore, a curl prevention layer may be provided on the surface of the base sheet on which the ink receiving layer is not formed.

(Ink Receiving Layer) The ink receiving layer 3 formed on one surface of the base sheet has a water-soluble resin and Tg of -1.
It is made of a hydrophilic resin at 00 ° C to 50 ° C. As described above, the ink receiving layer 3 has a water-soluble resin and Tg of −10.
Since it is a mixture with a hydrophilic resin at 0 ° C to 50 ° C, the adhesiveness to a base sheet, particularly a plastic base sheet becomes strong. The water-soluble resin used in the present invention is soluble in an aqueous solvent such as water or alcohol, and various conventionally known resins can be used. For example, polyvinyl alcohol, polyvinylpyrrolidone, poly (meth) acrylic acid, cellulose resin (CMC, HEC, HPC, etc.), polyacrylamide, polyethylene oxide, polyethylene glycol, polyvinyl acetal resin, polyvinyl methyl ether, polyamine, polyethyleneimine At least one of water-soluble resins such as casein, gelatin, and starch, and / or copolymers thereof, and cation / anion modified products are used.

Tg used in the present invention is -100 ° C to 50 ° C.
As the hydrophilic resin of, for example, alkyd resin, polyester resin, polyvinyl acetate resin, vinyl chloride vinyl acetate copolymer resin, NBR resin, SBR resin, polyurethane resin, acrylic resin, polyamide, etc., alone or as a mixture or modified product Used. The modified product is, for example, one having improved adhesion and hydrophilicity by copolymerizing or grafting a hydroxyl group, carboxylic acid, or quaternary ammonium salt-containing monomer (having improved compatibility with a water-soluble resin), etc. Is. Furthermore, the Tg of these resins is −100 ° C.
It is desirable that the temperature is -50 ° C. If the Tg exceeds this range, the adhesiveness between the base sheet and the ink receiving layer will deteriorate, which is not preferable. In addition, the curl resistance (cushioning property) is also reduced, and the ink drying property is also reduced. (In order to obtain sufficient adhesiveness, the amount of low Tg resin has to be increased, so that the hydrophobicity increases and the ink absorbability decreases.)

The above water-soluble resin and Tg are -100 ° C to 5
The mixing ratio of the water-soluble polyester resin, which is a hydrophilic resin at 0 ° C., is water-soluble resin / polyester resin = 20/1 to 1 /
20 is used, and particularly preferably 10/1 to 1/10
Is preferred. In addition, the range of 4/6 to 1/10 is preferable from the viewpoint of importance of adhesiveness, curl resistance and water resistance, and 10/1 to 10 from the viewpoint of importance of ink drying property and image clarity. A range of 6/4 is preferred.

Further, various polymers and additives may be added to the above composition for the purpose of improving blocking resistance, coating film strength, adhesion and dye fixing property. Examples thereof include silica, colloidal silica, clay, calcium carbonate, titanium oxide, organic fine particles, and fine particle fillers such as alumina sol. The particle size is preferably 0.1 to 20 μm, and it is preferable to add 0.1 to 10% of the total solid content. If it is less than 0.1%, a sufficient effect for preventing blocking cannot be obtained, and if it exceeds 10%, the transparency is deteriorated, which is not preferable for OHP applications. In addition, various surfactants, antioxidants, ultraviolet absorbers, antifoaming agents, various types of highly hydrophilic modified oils, and the like can be mixed and used as long as the effects of the present invention are not impaired.

The method for forming the above-mentioned ink receiving layer may be various conventionally known methods, for example, gravure coat, gravure reverse coat, roll coat, wire bar coat, blade coat, knife coat, air knife coat, comma coat. Any method such as slot die coating and dip coating may be used. If necessary, additives are added to the resin constituting the ink receiving layer, and a liquid dissolved or dispersed in a suitable solvent is coated on the base sheet,
Dry to provide the ink receiving layer. In addition, in order to secure the coating amount, the liquid having the same composition may be coated plural times. The thickness of the ink receiving layer is
The thickness is 0.1 to 50 μm, preferably 3 to 30 μm. If the thickness is less than 0.1 μm, the ink absorption amount is not sufficient, while if it exceeds 50 μm, the economical demerit increases, that is, the manufacturing cost increases, which is not preferable.

Further, an anti-curl layer, an antistatic layer or the like may be provided on the surface of the substrate sheet opposite to the surface on which the ink receiving layer is formed. As the anti-curl layer, it is possible to use the same water-soluble resin as the ink receiving layer, an acrylic resin, a polyester resin, or the like. In particular, when an acrylic resin, a modified acrylic resin, or a polyester resin is used, It is also useful in terms of imparting blocking property and slip property. The thickness of the anti-curl layer is 0.
The thickness is preferably about 1 to 50 μm, and the same method as the above-mentioned method for forming the ink receiving layer can be selected.

Further, an antistatic layer containing the following antistatic agent can be provided in order to prevent the recording sheet from being contaminated by dust and to stabilize the conveyance in the printer.
As the antistatic agent, conventionally known cations, anions,
Either a zwitterionic or nonionic antistatic agent can be used. Examples thereof include cationic antistatic agents such as quaternary ammonium salts and polyamine derivatives, anionic antistatic agents such as alkyl phosphates, and nonionic antistatic agents such as fatty acid esters. The antistatic layer may be added with the above antistatic agent and a lubricant such as an organic or inorganic filler, and a compounded solution obtained by dissolving or dispersing them in a solvent by a known method, that is, gravure coating, gravure reverse coating. , Roll coating, etc.,
Dry and form. The thickness of the antistatic layer is about 0.001 to 0.1 μm when dried.

[0019]

(Composition of ink receiving layer)

 Water-soluble resin: Polyvinyl alcohol 5 parts (solid content) (Kuraray Co., Ltd. PVA 210, polymerization degree 1000, saponification degree 88 mol%) Hydrophilic resin: Water-soluble polyester 5 parts (solid content) (Nippon Gosei Chemical Co., Ltd. ) Polyester WR950, Tg 34 ° C)

(Example 2) A recording sheet was prepared in the same manner as in Example 1 except that the composition of the ink receiving layer was changed as follows. [Composition of ink receiving layer] Water-soluble resin: polyvinyl alcohol 5 parts (solid content) (Kuraray Co., Ltd. PVA 217, degree of polymerization 1700, degree of saponification 88 mol%) Hydrophilic resin: styrene-butadiene copolymer 5 parts (Solid content) (Nihon ZEON Corporation Nipol SX1107, Tg 17 ° C)

Example 3 A recording sheet was prepared in the same manner as in Example 1 except that the composition of the ink receiving layer was changed as follows. [Composition of ink receiving layer] Water-soluble resin: polyvinylpyrrolidone 5 parts (solid content) (Kuraray Co., Ltd., Rubiscol K-90, molecular weight 70,000) Hydrophilic resin: acrylic acid ester 5 parts (solid content) (Nippon Zeon Corporation) Nipol SX1706 (Tg0 ° C)

(Example 4) A recording sheet was prepared in the same manner as in Example 1 except that the composition of the ink receiving layer was changed as follows. [Composition of ink receiving layer] Water-soluble resin: polyvinyl alcohol 10 parts (solid content) (Kuraray Co., Ltd. PVA 210, polymerization degree 1000, saponification degree 88 mol%) Hydrophilic resin: water-soluble polyester 1 part (solid content) ) (Nippon Gosei Kagaku Co., Ltd. Polyester WR950, Tg 34 ° C)

(Example 5) A recording sheet was prepared in the same manner as in Example 1 except that the composition of the ink receiving layer was changed as follows. [Composition of ink receiving layer] Water-soluble resin: polyvinyl alcohol 7 parts (solid content) (Kuraray Co., Ltd. PVA 210, polymerization degree 1000, saponification degree 88 mol%) Hydrophilic resin: water-soluble polyester 3 parts (solid content) ) (Nippon Gosei Kagaku Co., Ltd. Polyester WR950, Tg 34 ° C)

Example 6 A recording sheet was prepared in the same manner as in Example 1 except that the composition of the ink receiving layer was changed as follows. [Composition of ink receiving layer] Water-soluble resin: polyvinyl alcohol 3 parts (solid content) (Kuraray Co., Ltd. PVA 210, polymerization degree 1000, saponification degree 88 mol%) Hydrophilic resin: water-soluble polyester 7 parts (solid content) ) (Nippon Gosei Kagaku Co., Ltd. Polyester WR950, Tg 34 ° C)

Example 7 A recording sheet was prepared in the same manner as in Example 1 except that the composition of the ink receiving layer was changed as follows. [Composition of ink receiving layer] Water-soluble resin: polyvinyl alcohol 1 part (solid content) (Kuraray Co., Ltd. PVA 210, polymerization degree 1000, saponification degree 88 mol%) Hydrophilic resin: water-soluble polyester 10 parts (solid content) ) (Nippon Gosei Kagaku Co., Ltd. Polyester WR950, Tg 34 ° C)

Comparative Example 1 A recording sheet was prepared in the same manner as in Example 1 except that the composition of the ink receiving layer was changed as follows. [Composition of ink receiving layer] Water-soluble resin: polyvinyl alcohol 5 parts (solid content) (Kuraray Co., Ltd. PVA 217, degree of polymerization 1700, saponification degree 88 mol%) Hydrophilic resin: water-soluble polyester 5 parts (solid content) ) (Polyester WR901 manufactured by Nippon Synthetic Chemical Industry Co., Ltd., Tg 67 ° C.)

A test pattern was printed on the recording sheets of the above Examples and Comparative Examples using an inkjet printer (BJC-400J manufactured by CANON), and the results shown in Table 1 below were obtained. In addition, the evaluation method of each performance shown in Table 1 is as follows.

(1) Dryability After printing the test pattern, a sensory test was conducted by lightly rubbing the printed surface of the recording sheet with a finger. ◯: Dry within 1 minute after printing. Δ: Dry within 3 minutes after printing X: Drying takes 3 minutes or more.

(2) Image sharpness After printing the test pattern, the solid image uniformity, dot reproducibility, and character bleeding state were visually confirmed and evaluated. -Solid uniformity ：: Uniform ink spread is obtained. Δ: The spread of the ink was slightly uneven and unevenness was observed. X: The spread of the ink is non-uniform, and a pool of ink is observed.・ Dot reproducibility ○: The outline of overlapping dots can be clearly observed. Δ: The outline of overlapping dots can be almost observed. X: The outline of the overlapping dots is unclear and difficult to observe.・ Bleeding of characters ○: No bleeding of characters is observed even when characters are printed on the solid print part. Δ: When a character is printed on the solid print portion, some character bleeding is observed. X: When characters are printed on the solid print portion, character bleeding is observed.

(3) Adhesiveness The adhesiveness between the substrate sheet and the ink receiving layer was visually confirmed and evaluated. ○: Nichiban Cellotape, Elepack LP-1
The layer does not drop even if the tape is peeled off by rubbing 2 with the thumb 3 times back and forth on the ink receiving layer surface of the recording sheet. △: Sumitomo 3M Mending Tape, Sc
Even if an ochch810 11 mm width is rubbed on the ink receiving layer surface of the recording sheet with the thumb three times and the tape is peeled off, the layer hardly drops. ×: Sumitomo 3M Mending Tape, Sc
When the otch810 11 mm width is rubbed on the ink receiving layer surface of the recording sheet with the thumb three times and the tape is peeled off, the layer is easily dropped.

[0031]

[Table 1]

[0032]

The recording sheet of the present invention has a water-soluble resin and a Tg of -100 ° C to 5 on at least one side of the substrate sheet.
By providing an ink receiving layer mainly composed of a hydrophilic resin at 0 ° C., since it is a mixture of a hydrophilic resin having a Tg of −100 ° C. to 50 ° C. and a water-soluble resin, both the plastic substrate and the ink receiving layer can be obtained. Adhesiveness to ink is strong, ink absorbency is excellent, ink dryness is fast, and curling does not occur in the environment in which it is used.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing one embodiment of a recording sheet of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Recording sheet 2 Base sheet 3 Ink receiving layer

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[Procedure amendment]

[Submission date] January 30, 1996

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] Name of invention

[Correction method] Change

[Correction contents]

Title of the invention Recording sheet

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical display location B41M 5/04 B41M 5/04 D21H 19/20 D21H 1/34 F

Claims (3)

[Claims] 1. A recording sheet in which an ink receiving layer is provided on at least one surface of a base sheet, wherein the ink receiving layer is composed of a water-soluble resin and a hydrophilic resin having a Tg of −100 ° C. to 50 ° C. And a recording sheet. 2. The ink receiving layer as described above, wherein the polyvinyl resin is used as the water-soluble resin.
Recording sheet described in 1. 3. The recording sheet according to claim 1, wherein the base sheet is transparent.