JPH0781213A - Ink jet recording sheet - Google Patents

Abstract

PURPOSE:To enhance a sheet in ink absorbing and drying properties, ink fixing properties, transparency, color image forming properties, image sharpness, and anti-blocking properties by a method wherein an accepting layer made of a water soluble resin having a specific pH value when being taken into a water solution is provided on at least one surface of a substrate sheet. CONSTITUTION:An accepting layer 3 is provided on one surface of a substrate sheet 2 of a recording sheet. A back layer 4 is provided on the other surface, as required, for improving slipperiness and preventing curling this invention, the accepting layer 3 is made of a water soluble resin having a 5 or less pH value when being taken into a 10wt.% solid content solution in water. An inorganic filler having a particle diameter of 1-300nm is incorporated in the accepting layer 3 in the range of 1-80wt.% of the solid content of the composition of the accepting layer. As the inorganic filler, a colloidal silica or an alummna solid is used. As the water soluble resin, a polyacrylic acid, a polyacrylic acid copolymer, a cation-modified polyvinyl, alcohol, or the like is used. As the substrate sheet 2, a transparent material, is used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording sheet, and more particularly to a recording sheet having a receiving layer capable of recording with an ink jet printer on at least one surface of a base sheet.

[0002]

2. Description of the Related Art A conventional ink jet printer is a recording method for printing information obtained from a personal computer, word processor, etc., in addition to quietness and high-speed printing at the time of recording, sharpness of a picture and ease of colorization. And so on. And for presentations at conferences and conferences, overhead projectors (OH
P) is often used, and various demands for inkjet recording sheets used therefor are increasing.

Ink used in an ink jet printer is one in which the evaporation rate of the solvent is slowed in order to prevent defective ejection of the ink due to increase in viscosity due to evaporation of the ink solvent in the jet nozzle. This ink component is generally a dye, a polyhydric alcohol, various additives, etc. dissolved or dispersed in water. Therefore, in a recording sheet to be printed by an inkjet printer, particularly in the case of a plastic sheet, the receptive layer provided on the sheet surface is formed so as to have rapid water absorption, and accelerates the drying of the ejected ink. It was

In particular, the properties required for the receiving layer of the OHP sheet recorded by an ink jet printer are as follows. Good ink receptivity, dryness (rapid water absorption), and fixability. High transparency. When the recording sheets are stored in a laminated state, the receptive layer surface and the back surface layer or the receptive layer surface and the sheet surface do not adhere to each other (blocking), which lowers the receptive performance and causes no trouble in running on a printer. In order to prevent white spots in the image, the ink dots should spread appropriately and should not have excessive bleeding. The formed image is clear and has no discoloration. There should be no stickiness, dust, or fingerprints.

[0005]

In order to achieve these required characteristics, conventionally, a base sheet is coated with a water-soluble resin, or the water-soluble resin has a particle size of several μm as follows.
A composition coated with a certain amount of an inorganic filler was used. Some conventional recording sheets coated with a water-soluble resin as the ink receiving layer have some improvement in ink drying property, but they are not suitable for high speed printing.
Further, since it has high hygroscopicity and poor water resistance, it is apt to cause blocking, and there is a problem that the receptor layer peels off due to the adhesion of moisture and falls off. Further, when a water-proofing agent or the like is added, there is a problem that the absorbability of ink is lowered and the printed image is disturbed.

Further, in the case where the inorganic filler is added to the water-soluble resin, if the addition ratio of the filler is low, the high speed drying property of the ink cannot be satisfied, so that the ratio of the filler is increased. Therefore, the ink absorbency is improved,
Although high-speed drying property can be satisfied, conversely, when the receiving layer is applied and dried, cracks easily occur, the receiving layer becomes brittle, cracks occur, and it becomes difficult to obtain a uniform sheet. there were.

On the other hand, Japanese Patent Application Laid-Open No. 57-14091 discloses an invention in which 60% or more of organic fine particles are filled to form a porous layer as an ink receiving layer.
However, this product did not have cracks, but lacked transparency, and since a hydrophobic resin was used as the binder resin, the drying property was not satisfactory. Further, Japanese Patent Laid-Open No. 61-19389 discloses an invention in which a water-soluble neutral resin such as polyvinyl alcohol or gelatin is filled with colloidal silica having a particle size of 8 to 30 nm as an ink receiving layer. However, according to the present invention, the fixing property and the drying property of the ink using the anionic dye were not sufficient.

The recording sheet of the present invention solves the above problems and is used for ink jet printers excellent in ink absorption and drying properties, fixing properties, sheet transparency, image color development, sharpness and blocking resistance. The purpose is to provide a recording sheet.

[0009]

The above objects have been achieved by the present invention described below. That is, according to the invention of claim 1, at least one surface of the substrate sheet has a solid content of 1%.
An ink jet recording sheet, comprising a receiving layer made of a water-soluble resin having a pH of 5 or less in an aqueous solution at 0% by weight.

According to the second aspect of the present invention, the receptive layer contains an inorganic filler having a particle size of 1 to 300 nm in a range of 10 to 80% by weight based on the solid content of the receptive layer composition. The inkjet recording sheet according to claim 1. In the invention of claim 3, at least one of the inorganic fillers is colloidal silica or
The inkjet recording sheet according to claim 2, wherein the recording sheet is an alumina sol.

The invention of claim 4 is characterized in that at least one of the water-soluble resins is any one of polyacrylic acid, polyacrylic acid-based copolymer, and cation-modified polyvinyl alcohol. The recording sheet for inkjet according to 1, 2, and 3. The invention according to claim 5 is the inkjet recording sheet according to any one of claims 1, 2, 3, and 4, wherein the base material sheet is transparent.

[0012]

In the ink jet recording sheet of the present invention, a water-soluble resin having a pH of 5 or less in an aqueous solution at a solid content of 10% by weight is used for a receptive layer. Also has good fixability, and since the particle size of the inorganic filler is 1 to 300 nm, even if a large amount of this is included, the film of the receiving layer does not crack, and the transparency, drying property, and blocking resistance are high. It has the effect of being excellent in properties.

The present invention will be described in more detail below with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing one embodiment of the constitution of the inkjet recording sheet of the present invention. That is, the structure shows that the receiving layer 3 is provided on one surface of the base material sheet 2, and the back surface layer 4 is provided on the other surface for the purpose of improving slipperiness and preventing curling, if necessary.

The base sheet 2 is preferably formed of a thermoplastic sheet having transparency, heat resistance, dimensional stability against humidity, and moderate rigidity. For example, 2
Axial stretched polyethylene terephthalate, cellulose triacetate, polycarbonate, polyvinyl chloride, etc. 50
A sheet of ˜250 μm can be mentioned. And
More preferred is a 75-180 μm biaxially oriented polyethylene terephthalate film. If transparency is not particularly required, clay-coated paper, polypropylene-based or polystyrene-based synthetic paper, etc. can be selected according to the application.

The recording sheet of the present invention is provided with a primer layer after surface activation by corona discharge treatment or a primer layer in order to stabilize the adhesiveness depending on the type of substrate sheet and the type of receiving layer coating liquid. A receiving layer can also be provided. As the primer layer, an acrylic resin or urethane resin such as a one-component or two-component curable polyacrylic acid derivative, which is a commonly used material, depending on the type of the base sheet, or
Linear polyester resin, vinyl chloride / vinyl acetate copolymer, nitrified cotton, etc. can be used. The coating is carried out by a usual gravure coating, reverse roll coating, direct roll coating or the like, and the thickness of the coating film after drying is preferably about 0.1 to 1.0 μm.

Further, the non-receptive layer side is provided with a slip property for improving feed suitability in an ink jet printer, and at the same time, for the purpose of preventing curling caused by adhesion of foreign matter and expansion / contraction of the receptive layer due to expansion and contraction. It is also possible to provide a back surface layer formed of a varnish of the same type as the above or a varnish of a fibrin derivative or the like.

The ink receiving layer is formed mainly of a water-soluble resin having a PH of 5 or less, preferably PH2-4, when the solid content is 10% by weight. When the pH is 5 or more, the fixability of the ink using the anionic dye is particularly impaired, and when the PH is 2 or less, the color developability may be impaired depending on the properties of the ink. As these water-soluble resins, polyacrylic acid, polyacrylic acid copolymer, polymethacrylic acid, cation-modified polyvinyl alcohol and the like can be used, and particularly preferred are polyacrylic acid, polyacrylic acid copolymer, cation-modified It is polyvinyl alcohol.

Further, as a film forming aid for the coating liquid for the receptive layer mainly composed of a water-soluble resin, ethylene glycol, ethylene glycol n-butyl ether, diethylene glycol n-butyl ether, propylene glycol n-butyl ether, dipropylene glycol n-butyl ether. Etc. can also be added.

If necessary, inorganic fine particles may be added to the ink receiving layer of the present invention. The fine particles have a particle diameter of 1 to 300 nm, and those having a refractive index of around 1.4 do not impair transparency even if the content is increased, and therefore are effective when used for a transparent sheet. is there. The amount of the inorganic filler in the receiving layer is 10 to 8 based on the solid content ratio of the receiving layer composition.
It is 0% by weight, preferably 60 to 80% by weight.
Depending on the kind of the filler, when the content is 60% by weight or less, there is little effect on improving the blocking resistance and surface tackiness, and when it is 80% by weight or more, the transparency is impaired,
It is not preferable because fine cracking may occur.

In the above ink receiving layer, the pH can be controlled by adding a pH adjusting agent such as amine, and the fixing property and color forming property can be set according to the properties of the ink. The ink receiving layer can be formed by appropriately selecting from the usual coating methods such as gravure coating, roll coating, knife coating, curtain coating, and air knife coating. The coating thickness of the ink receiving layer is preferably about 1 to 50 μm.

[0021]

EXAMPLES The present invention will now be described in detail with reference to examples. In addition, "part" or "%" in the text is based on weight unless otherwise specified. (Example 1) As a base material sheet, a biaxially stretched polyethylene terephthalate sheet having a thickness of 100 μm [Toray Industries, Inc.]
The coating composition for a primer having the following composition was applied to one side of the sheet by gravure coating so that the coating amount was 1 g / m ² (solid content). Coating solution for layer is coated with bar coater at 15 g /
The ink receiving layer was provided by coating so as to have a m ² (solid content). Further, the sheet is sheeted to a desired size and then the first embodiment is used.
To obtain an inkjet recording sheet. Composition of coating liquid for primer Polyester polyol Adcoat [manufactured by Toyo Morton Co., Ltd.] 15 parts Mixed solvent methyl ethyl ketone / toluene (weight ratio 2: 1) 85 parts Composition of coating liquid for receiving layer Polyacrylic acid AQ-3930 Molecular weight 800,000 solid Min 10% [Nippon Shokubai Co., Ltd.] 100 parts

(Example 2) In the constitution of Example 1, only the coating liquid for the ink receiving layer was changed to the coating liquid having the following composition, and the other processing conditions were the same as those of Example 1, and An inkjet recording sheet was obtained. Composition of Receptor Layer Coating Liquid Polyacrylic acid HL-521 Molecular weight 200,000 Solid content 20% [manufactured by Nippon Shokubai Co., Ltd.] 100 parts

(Example 3) In the constitution of Example 1, only the coating liquid for the ink receiving layer was changed to the coating liquid of the following composition, and the other processes were carried out in the same manner as in Example 1 to prepare the ink for inkjet of Example 3. A recording sheet was obtained. Composition of coating liquid for receiving layer Polyacrylic acid AQ-3930 Molecular weight 800,000 Solid content 10% [Nippon Catalyst Co., Ltd.] 40 parts Colloidal silica O-40 Particle size 10-20 nm Solid content 40% [Nissan Chemical Industry Co., Ltd. ) Made 30 parts

(Example 4) In the constitution of Example 1, only the coating liquid for the ink receiving layer was changed to the coating liquid having the following composition, and the other processes were carried out in the same manner as in Example 1 to prepare the ink for inkjet of Example 4. A recording sheet was obtained. Composition of coating liquid for receptor layer Polyacrylic acid AQ-3930 Molecular weight 800,000 Solid content 10% [Nippon Shokubai Co., Ltd.] 40 parts Colloidal silica ST-OL Particle size 40-50 nm Solid content 20% [Nissan Chemical Industry Co., Ltd. ) Made] 15 parts

(Example 5) In the constitution of Example 1, only the coating liquid for the ink receiving layer was changed to the coating liquid having the following composition, and the other processes were carried out in the same manner as in Example 1 to prepare the ink for the ink jet of Example 5. A recording sheet was obtained. Composition of Receptor Layer Coating Liquid Polyacrylic acid HL-521 Molecular weight 200,000 Solid content 20% [manufactured by Nippon Shokubai Co., Ltd.] 20 parts Alumina sol 520 Particle size 10-20 nm Solid content 20% [manufactured by Nissan Chemical Industries, Ltd.] 60 copies

(Example 6) In the constitution of Example 1, only the coating liquid for the ink receiving layer was changed to the coating liquid of the following composition, and the other processes were carried out in the same manner as in Example 1 to prepare the ink for the ink jet of Example 6. A recording sheet was obtained. Composition of coating liquid for receptor layer Cation-modified polyvinyl alcohol K-210 Solid content 10% Polymerization degree 1700 [Nippon Gosei Kagaku Kogyo Co., Ltd.] 25 parts Colloidal silica O-40 Particle size 10-20 nm Solid content 40% [Nissan Chemical Industrial Co., Ltd.] 75 parts

(Example 7) In the constitution of Example 1, only the coating liquid for the ink receiving layer was changed to the coating liquid having the following composition, and the other processes were carried out in the same manner as in Example 1 for the ink jet recording of Example 7. A recording sheet was obtained. Composition of coating liquid for receiving layer Polyacrylic acid AQ-3930 Molecular weight 800,000 Solid content 10% [manufactured by Nippon Shokubai] 40 parts Colloidal silica PST-3 Particle size 300 nm Solid content 20% [manufactured by Nissan Chemical Industries, Ltd.] ] 15 copies

(Example 8) In the constitution of Example 1, only the coating liquid for the ink receiving layer was changed to the coating liquid having the following composition, and the other processes were carried out in the same manner as in Example 1 to prepare the ink for ink jet of Example 8. A recording sheet was obtained. Composition of Receptor Layer Coating Liquid Polyacrylic acid copolymer AC-20L Polymerization degree 600 Solid content 40% [Nippon Pure Chemical Co., Ltd.] 100 parts

(Comparative Example 1) In the constitution of Example 1, only the coating liquid for the ink receiving layer was changed to the coating liquid having the following composition, and the other processes were carried out in the same manner as in Example 1 to prepare the ink composition for inkjet of Comparative Example 1. A recording sheet was obtained. Composition of Receptor Layer Coating Liquid Polyacrylic acid AQ-3930 Molecular weight 800,000 Solid content 10% [manufactured by Nippon Shokubai Co., Ltd.] 97 parts Silica powder Silysia 456 Particle size 5.5 [mu] m [manufactured by Fuji Silysia Chemical Ltd.] 3 parts

(Comparative Example 2) In the constitution of Example 1, only the coating liquid for the ink receiving layer was changed to the coating liquid having the following composition, and the other processing was carried out in the same manner as in Example 1 to prepare the ink for the ink jet of Comparative Example 2. A recording sheet was obtained. Composition of Receptor Layer Coating Liquid Sodium Polyacrylate HL-522 Molecular Weight 200,000 Solid Content 30% [Nippon Shokubai Co., Ltd.] 100 Parts

(Comparative Example 3) In the constitution of Example 1, only the coating liquid for the ink receiving layer was changed to the coating liquid having the following composition, and the other processes were carried out in the same manner as in Example 1 to prepare the ink composition of Comparative Example 3. A recording sheet was obtained. Composition of Receptor Layer Coating Liquid Sodium polyacrylate HL-522 Molecular weight 200,000 Solid content 30% [Nippon Shokubai Co., Ltd.] 20 parts Colloidal silica ST-C Particle size 10 to 20 μm Solid content 20% [Nissan Chemical Industry ( Co., Ltd.] 90 parts

(Comparative Example 4) In the constitution of Example 1, only the coating liquid for the ink receiving layer was changed to the coating liquid having the following composition, and the other processing was carried out in the same manner as in Example 1 to prepare the ink for the inkjet of Comparative Example 4. A recording sheet was obtained. Composition of coating liquid for receiving layer Polyacrylic acid AQ-3930 Molecular weight 800,000 Solid content 10% [manufactured by Nippon Shokubai Co., Ltd.] 40 parts Colloidal silica PST-5 Particle size 500 μm Solid content 20% [Nissan Chemical Industry Co., Ltd.] ] 15 copies

(Evaluation and Results) Using each of the recording sheets of Examples 1 to 8 and Comparative Examples 1 to 4 as a sample, the performance of the ink receiving layer was evaluated by the ink drying property, blocking resistance, transparency, and ink coloring. Each of the items of releasability and fixability was evaluated, and the results are shown in Table 1.

[0034]

[Table 1] (Note) ◎: Excellent ○: Good △: Slightly inferior, but practical
X: Inferior * PH is indicated by a value measured with an aqueous solution of a water-soluble resin having a solid content of 10% by weight.

The results in Table 1 are evaluated by the following method. 1) Ink drying property: 3 minutes and 5 minutes after the completion of printing on the recording sheet, a high-quality paper is placed on the black solid print portion, and the ink is applied from the top 20
After applying a load of g / cm ² , the presence or absence of transfer of ink to the paper was evaluated. ◯: None was transferred. Δ: Transferred only after 3 minutes. ×:
Transferring occurs even after 5 minutes 2) Blocking resistance: 10 recording sheets are stacked so that the receiving layer and the back surface face each other, 10 g / cm ²
Under a constant temperature and humidity of 30 ° C and 90% RH.
After standing for a day, the adhesion state of the sheet was evaluated. ◎: No adhesion at all ○: Very light adhesion △: Light adhesion
X: Slightly strong adhesion 3) Transparency: Haze meter 10 manufactured by Nippon Denshoku Industries Co., Ltd.
The turbidity of the sheet was measured by 01DP and evaluated. ◯: Turbidity of 7.0 or less ×: Turbidity of 7.0 or more 4) Ink coloring: A color image was recorded on a recording sheet, and the coloring and vividness were visually evaluated. ◯: Good x: Inferior 5) Ink fixability: A test pattern was printed on a recording sheet and allowed to stand for 1 week at 50 ° C. in a dry state, and then the presence or absence of ink bleeding was evaluated. ○: No bleeding ×: There is bleeding

[0036]

As described above, the ink jet recording sheet of the present invention is mainly composed of a water-soluble resin having a PH of 5 or less in an aqueous solution at a solid content of 10% by weight on at least one surface of a substrate sheet. The ink receiving layer in which an inorganic filler having a particle diameter of 300 nm or less is dispersed as a component is provided. By adopting such a constitution, it is possible to provide an ink jet recording sheet which is extremely excellent in ink fixing property, color developing property, drying property, sheet transparency and blocking resistance.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing an example of the configuration of an inkjet recording sheet of the present invention.

[Explanation of reference numerals] 1 inkjet recording sheet 2 base sheet 3 receiving layer 4 back surface layer

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Masafumi Hayashi 1-1-1 Ichigaya-Kagacho, Shinjuku-ku, Tokyo Dai Nippon Printing Co., Ltd.

Claims (5)

[Claims] 1. An ink jet recording characterized in that a receiving layer composed of a water-soluble resin whose pH of an aqueous solution at a solid content of 10% by weight is 5 or less is provided on at least one surface of a substrate sheet. Sheet. 2. An inorganic filler having a particle size of 1 to 300 nm is contained in the receiving layer in a solid content ratio of the receiving layer composition of 10 to 8.
The inkjet recording sheet according to claim 1, wherein the content is 0% by weight. 3. The ink jet recording sheet according to claim 2, wherein at least one of the inorganic fillers is colloidal silica or alumina sol. 4. The method according to claim 1, wherein at least one of the water-soluble resins is any one of polyacrylic acid, polyacrylic acid-based copolymer, and cation-modified polyvinyl alcohol. Recording sheet for inkjet. 5. The inkjet recording sheet according to claim 1, wherein the base sheet is transparent.