JPH07108754A - Recording sheet - Google Patents

Abstract

PURPOSE:To obtain a recording sheet improved in ink absorbing, drying and fixing properties by providing an ink receiving layer consisting of a polymeric compsn. and a mixture of two or more kinds of fine particles different in dye fixing properties on one surface of a base material sheet. CONSTITUTION:A recording sheet A is produced by providing an ink receiving layer consisting of a polymeric compsn. and a filler on at least one surface of a base material sheet 1. The filler is constituted of a mixture of two or more kinds of fine particles different in dye fixing properties and, concretely, there are org. ultrafine particles, a silica sol, an alumina sol or the like and the compounding amt. thereof is pref. 20-500wt.% of the solid of the polymeric compsn. The polymeric compsn. is constituted of polyvinyl alcohol and a cation modified substance thereof, polyvinyl acetal or a mixture of them. A silica powder with a particle size of 5-20mum is added to the ink receiving layer in an amt. of 0.1-5wt.% of the solid of the polymeric compsn.

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 transparent base sheet and a receiving layer on at least one surface of which a recording can be performed by an ink jet printer.

[0002]

2. Description of the Related Art A conventional ink jet printer is a recording method for printing information obtained from a personal computer, a word processor, etc., in addition to quietness and high speed printing at the time of recording, sharpness of a picture and easy colorization. It has excellent properties and the like. In addition, an overhead projector (OHP) is often used instead of a conventional slide projector for presentations at conferences and presentations at various academic conferences, and the demand for the sheet is increasing.

The ink used in the ink jet printer has a slower drying speed in order to prevent defective ejection of the ink due to increase in viscosity due to evaporation and drying 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, the receptive layer provided on the surface of the recording sheet, particularly the plastic sheet, which is printed by the ink jet printer is formed so as to have rapid water absorption, and accelerates the drying of the ejected ink.

In particular, the following properties are required for the receiving layer of an OHP sheet recorded by an ink jet printer. Good ink receptivity, dryness (rapid water absorption), and fixability. High transparency. When the recording sheets are stored in a laminated state, the coated surface and the sheet or the coated surface and the coated surface should be in intimate contact (blocking) to prevent running troubles in the printer. In order to prevent white spots in the image, the ink dots should spread appropriately and excessive bleeding should be avoided. The formed image is clear and has no discoloration. There should be no stickiness, dust, or fingerprints. In order to achieve these required properties, conventionally, a polymer composition coated or a polymer composition added with an inorganic filler has been used.

[0005]

In a conventional recording sheet coated with a polymer composition, the ink drying property is improved to some extent, but it is not suitable for high-speed printing, and
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. When a water-proofing agent or the like is added, there is a problem that the absorbability of the ink is lowered and the printed image is disturbed. Further, in the case where the inorganic filler is added to the polymer composition, when the proportion of the filler is small, the high speed drying property of the ink cannot be satisfied, and as the proportion of the filler is increased, Although the ink absorbency is improved and the high-speed drying property can be satisfied, cracks are likely to occur when the receiving layer is applied and dried, and the receiving layer becomes brittle and cracked, and a uniform sheet can be obtained. There was a problem that it would be difficult.

The recording sheet of the present invention is a recording material of an ink jet printer which is excellent in ink absorbing and drying property, fixing property, sheet transparency, image colorability, sharpness, durability, water resistance, blocking resistance and the like. The purpose is to provide a sheet for.

[0007]

In order to achieve the above object, a recording sheet having an ink receiving layer composed of a polymer composition and a filler on at least one surface of a base sheet is used. Is a mixture of two or more kinds of fine particles having different dye fixing properties. The filler is selected from organic ultrafine particles, silica sol, and alumina sol, and constitutes 20 to 500% by weight based on the solid content of the polymer composition. The polymer composition is polyvinyl alcohol and its cation modified product, polyvinyl acetal, acrylic resin and its cation modified product, or a mixture thereof. Further, it is a recording sheet in which the silica powder having a particle size of 5 to 20 μm is contained in the ink receiving layer in the range of 0.1 to 5% by weight based on the solid content of the polymer composition.

In the ink receiving layer composed of the polymer composition and the filler, when only the silica sol is used as the filler, a satisfactory drying property is obtained, but the following drawbacks occur. Since the silica sol has a low dye fixing property, the ink is not sufficiently absorbed, and the screen is disturbed by bleeding. When the proportion of the water-dispersed polymer composition is increased, the fixing of the dye is improved, but the ink drying speed is decreased. Weak adhesion to the base sheet.

Further, in the ink receiving layer composed of the polymer composition and the filler, when only alumina sol is used as the filler, the drying property is satisfactory, but the following drawbacks occur. Alumina sol has too strong dye fixing ability, so it is not possible to obtain a suitable dot spread, resulting in an image with thin lines,
In some cases, the color development of the ink is modulated, resulting in poor color reproducibility. When the proportion of the polymer composition is increased, an appropriate dye fixing property is obtained, but the drying property of the ink is lowered.

Therefore, a recording sheet used for an ink jet printer having excellent ink absorption and drying properties and fixing properties, sheet transparency, water resistance, blocking resistance, and image coloring properties, vividness, and durability is provided. In order to obtain it, it is preferable to use a combination of anionic fine particles having a weak dye fixing property as a filler and cationic fine particles having a strong dye fixing property. As shown in FIG. 1, the recording sheet of the present invention has a substrate sheet 1 on which an ink receiving layer 2 containing two or more kinds of fine particles having different dye fixing properties is provided.

The organic ultrafine particles used as one kind of filler in the present invention include vinyl polymers such as styrene, acrylic acid derivatives, methacrylic acid derivatives, vinyl acetate and the like, and copolymers. . These fine particles are carboxyl group, carboxylic acid anhydride, carboxylate salt, hydroxyl group, epoxy group, methylol group, alkoxymethylol group, amide group, amino group, isocyanate group,
By introducing a chloro group into a vinyl polymer, it can be provided as a functional group on the surface of fine particles, and the dye fixing property can be adjusted by selecting these functional groups. In particular, those having an amino group introduced therein can be used as dyeable particles having a strong adhesive force. Examples thereof include polymethyl methacrylate, polystyrene, poly n-butyl acrylate, polyvinyl acetate, benzoguanamine, polyamide, epoxy resin, polyglycidyl methacrylate and copolymers thereof. In addition, examples of the material having a low dye fixing property include polyethylene oxide and particles containing vinyl acetate. The primary particle diameter of these particles is preferably 1 μm or less. Especially when transparency is required, finer particles of 0.3 μm or less are preferable. The degree of crosslinking of particles is 5
It is preferable to adjust it to 0 mmol / g or less, and it is also possible to form layered particles.

When silica sol is used as one of the fillers, it is preferable that the surface of the silica sol is negatively charged, or the surface treatment is performed so as to have a positive charge of an aluminum compound or the like, and the dye fixing property is changed by this charge. You can also Generally, when the negative charge is strong, the dye fixability is weak, and when the positive charge is strong, the dye fixability is strong. The primary particle diameter of these particles is preferably 1 μm or less. Especially when transparency is required, a finer size of 0.3 μm or less is preferable. Further, the shape thereof is a spherical shape or a chain of these. In particular,
The chain-like material is also effective in that cracks hardly occur even when the proportion of the filler is increased.

When alumina sol is used as one of the fillers, it is composed of alumina hydrate. Alumina sol is effective as particles having a strong dye fixing property due to the cationic property of aluminum on its surface. The primary particle size of these particles is preferably 1 μm or less, and when the transparency is particularly required, a finer size of 0.3 μm or less is preferable. Further, the shape thereof is feathery, rod-like, or granular.

As the polymer composition, a conventionally known composition can be used as long as it can be dispersed by mixing a filler without causing aggregation and gelation. When alumina sol is used as the filler, cation and nonionic polymers are preferable, and polyvinylpyrrolidone, polyvinyl alcohol, polyvinyl acetal, cellulose and cation modified products thereof are suitable. Besides this, gelatin,
Cellulose derivative, styrene-butadiene latex,
Polyamide, polyamine, polyimine, polyacrylic acid, sodium polyacrylate, polyvinyl methyl ether, polyethyleneimine, water-soluble resin such as polyacrylamide, chitin, chitosan, starch, polyethylene oxide, or a mixture thereof, or a cation thereof, Alternatively, anion-modified one can be used. Particularly preferred are polyvinyl alcohol and its cation-modified product, polyvinyl acetal, acrylic resin and its cation-modified product, or a mixture thereof.

The proportion of the filler with respect to the solid content of the polymer composition is in the range of 2 to 2000% by weight, and in the range of 20 to 500% by weight in terms of ink absorbency, drying property and fixing property. Is preferred. If it is more than this range, the image tends to be disturbed, and if it is less than this range, the one which satisfies the ink drying property cannot be obtained.

The mixing ratio of only the filler particles varies depending on the type of particles used, but is in the range of strong dye fixing particles / weak dye fixing particles = 1/100 to 1 (weight ratio), and particularly ink. The range of 1/30 to 3 (weight ratio) is preferable from the viewpoints of absorptivity, drying property, and fixing property. If the amount of the strong dye fixing particles is too large, the image is disturbed, and if the amount of the weak dye fixing particles is too large, sufficient ink drying property cannot be obtained. From these viewpoints, when the polymer composition is mainly a resin having a low dye fixing property, the ratio of the strong dye fixing particles is increased, and conversely, the polymer composition is a resin having a high dye fixing property. When it is mainly, the ratio of the weak dye fixing particles should be increased.

The silica powder used as an antiblocking agent preferably has a particle size of 5 to 20 μm, and is preferably added in the range of 0.1 to 5% by weight based on the total solid content of the ink receiving layer. If it is less than this range, sufficient effect for preventing blocking cannot be obtained, and if it is more than this range, there is a problem that transparency is impaired.

Alcohols such as ethylene glycol, ethylene glycol n-butyl ether, diethylene glycol n-butyl ether, propylene glycol n-butyl ether and dipropylene glycol are used as film-forming aids in the coating solution for the receptor layer, which is mainly composed of the polymer composition. n
-Butyl ether and the like can also be added.

The additive for the purpose of improving the surface of the receptive layer formed from the receptive layer coating liquid mainly comprising a polymer composition is an alkylammonium acetate (R-NH ₂ H.0COCH) which is a surfactant. By adding ₃ ) and sizing agents such as rosin and starch to the coating solution, the wettability and drying properties of the ink are improved.

The receiving layer of the present invention is provided in the range of 5 to 50 g / m ² (solid content). Then, the coating method is a direct roll coating generally used,
It can be appropriately selected from reverse roll coating and air knife coating.

The base sheet 1 shown in FIG. 1 is preferably formed of a thermoplastic sheet having transparency, heat resistance, dimensional stability against humidity, and appropriate rigidity.
For example, a sheet of stretched polyethylene terephthalate, cellulose triacetate, polycarbonate, polyvinyl chloride or the like having a thickness of 50 to 250 μm can be used. And a preferable thing is a 75-180 micrometer polyethylene terephthalate sheet. The recording sheet of the present invention, in order to stabilize the adhesiveness depending on the type of base sheet and the type of receiving layer coating liquid, surface activation by corona discharge treatment, or a receiving layer on which a primer layer is provided. Can be provided. The primer layer, which depends on the type of the base sheet, is a commonly used material, linear polyester,
There is a varnish made of an acrylic resin such as a one- or two-component curable polyacrylic acid derivative, a polyurethane resin, a vinyl chloride / vinyl acetate copolymer, and nitrified cotton. The coating is carried out by a usual gravure coating, reverse roll coating, direct roll coating, etc., and the coating thickness after drying is preferably 0.1 to 1.0 μm.

Further, on the non-receptive layer side, the same as the receptive layer is provided for the purpose of improving the slip to give a feed suitability on a printing machine and preventing curling due to adhesion of foreign matter and expansion / contraction of the receptive layer due to moisture absorption / dehumidification. A back surface coating layer formed of a varnish of a system, or a varnish of a polyacrylic ester resin, a fibrin derivative or the like is provided.

[0023]

In the recording sheet having the above-described structure, the receiving layer thereof contains cationic fine particles having a good dye fixing property and anionic fine particles having a low dye fixing property but capable of promoting ink drying property. The receiving layer provided so that the coating liquid can be applied and formed in a stable state by being mixed into a polymer composition to have a dye fixing property, good ink drying property, and water resistance. It works so that there is no image distortion.

[0024]

【Example】

Example 1 As a base material sheet 1, polyethylene terephthalate sheet Q80D 100 μm manufactured by Toray Industries, Inc. was coated with “Receptor layer coating liquid 1” having the following composition by reverse roll coating at a coating amount of 10 g / m ² (solid content). The coating solution was applied as described above and dried at 80 ° C. for 5 minutes to provide the receiving layer 2, and a recording sheet A of the present invention was prepared. Hereinafter, the compounding ratio is based on weight unless otherwise specified. "Receptor layer coating liquid 1" Cation-modified polyvinyl alcohol 10% aqueous solution 30 parts (PVA K-210 manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) Silica sol Particle size 10 to 20 μm 15% sol 10 parts (Nissan Chemical Co., Ltd. Snowtex) OUP) Alumina sol Particle size 0.1-0.01 μm 10% sol 15 parts (Nissan Chemical Industry Feather Alumina sol-100)

Example 2 As the base sheet 1, a polyethylene terephthalate sheet Q80D100 manufactured by Toray Industries, Inc.
μm of “Receptor Layer Coating Liquid 2” having the following composition was applied by reverse roll coating so that the coating amount was 10 g / m ² (solid content), and dried at 80 ° C. for 5 minutes to obtain a receptor layer. 2 was provided to prepare a recording sheet A of the present invention. "Receptor layer coating liquid 2" Polyvinylpyrrolidone 10% aqueous solution 40 parts (BASF Corporation Rubiscol K-90) Silica sol particle size 10 to 20 μm 40% sol 5 parts (Nissan Chemical Co., Ltd. Snowtex-40) Organic ultrafine particles Particle size 0.1 μm 20% dispersion 10 parts (Nippon Paint Co., Ltd. surface functional group-NH ₂ ).

Example 3 As the base material sheet 1, a polyethylene terephthalate sheet Q80D100 manufactured by Toray Industries, Inc.
μm of “Receptor Layer Coating Liquid 3” having the following composition was applied by reverse roll coating so that the coating amount was 10 g / m ² (solid content), and dried at 80 ° C. for 5 minutes to obtain a receptor layer. 2 was provided to prepare a recording sheet A of the present invention. "Receptor layer coating liquid 3" Polyvinyl alcohol 10% aqueous solution 7 parts (Kuraray Co., Ltd. PVA 117) Silica powder particle size 5 μm 2 parts (Fuji Silysia Chemical Ltd. Syloid 162) Organic ultrafine particles particle size 0.06 μm 20% Dispersion 0.5 part (Nippon Paint Co., Ltd. surface functional group-COOH) Alumina sol Particle size 0.1 μm to 0.01 μm 10% sol 7 parts (Nissan Chemical Co., Ltd. Feather alumina sol 200)

Example 4 As the base material sheet 1, a polyethylene terephthalate sheet Q80D100 manufactured by Toray Industries, Inc.
μm of “Receptor Layer Coating Liquid 1” having the following composition was applied by reverse roll coating so that the coating amount was 10 g / m ² (solid content), and dried at 80 ° C. for 5 minutes to form a receptor layer. 2 was provided to prepare a recording sheet A of the present invention. "Receptor layer coating liquid 4" Cation-modified polyvinyl alcohol 10% aqueous solution 30 parts (PVA K-210 manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) Silica powder particle size 10 µm 0.035 parts (Fuji Silysia Chemical Co., Ltd. Cyloid 620) Silica sol Particle size 10 to 20 nm 15% sol 2 parts (Nissan Chemical Co., Ltd. Snowtex OUP) Alumina sol Particle size 0.1 to 0.01 μm 10% sol 3 parts (Nissan Chemical Industry Feather Alumina sol-100)

[Embodiment 5] As a base material sheet 1, a polyethylene terephthalate sheet Q80D100 manufactured by Toray Industries, Inc.
μm of “Receptor Layer Coating Liquid 5” having the following composition was applied by reverse roll coating so that the coating amount was 10 g / m ² (solid content), and dried at 80 ° C. for 5 minutes to obtain a receptor layer. 2 was provided to prepare a recording sheet A of the present invention. Some cracks were generated on the receiving layer surface during coating and drying. "Receptor layer coating liquid 5" Cation-modified polyvinyl alcohol 10% aqueous solution 30 parts (PVA K-210 manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) Silica sol Particle size 10-20 nm 15% sol 60 parts (Nissan Chemical Industry Snowtex Co., Ltd.) OUP) Alumina sol Particle size 0.1-0.01 μm 10% sol 60 parts (Nissan Chemical Industry Co., Ltd. Feather alumina sol-100)

[0029]

[Comparative example]

[Comparative Example 1] As a base material sheet 1, a polyethylene terephthalate sheet Q80D 100 µm manufactured by Toray Industries, Inc., was coated with "Receptor layer coating liquid 6" having the following composition by reverse roll coating at a coating amount of 10 g / m ² (solid content). The coating solution was applied as described above and dried at 80 ° C. for 5 minutes to provide the receiving layer 2, and a recording sheet A of the present invention was prepared. "Receptor layer coating liquid 6" Polyvinyl alcohol 10% aqueous solution 30 parts (Japan Synthetic Chemical Industry Co., Ltd. GH17) Silica sol Particle size 10 to 30 nm 20% sol 5 parts (Nissan Chemical Co., Ltd. Snowtex O)

[Comparative Example 2] As the base material sheet 1, a polyethylene terephthalate sheet Q80D100 manufactured by Toray Industries, Inc.
μm of “Receptive Layer Coating Liquid 7” having the following composition was applied by reverse roll coating so that the coating amount was 10 g / m ² (solid content), dried at 80 ° C. for 5 minutes, and then received. Layer 2 was provided to prepare recording sheet A of the present invention. "Receptor layer coating liquid 7" Polyvinyl alcohol 10% aqueous solution 30 parts (GH17 manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) Organic ultrafine particles particle size 0.06 µm 20% dispersion liquid 0.5 part (manufactured by Nippon Paint Co., Ltd. E 503) )

The above-described recording sheets of the examples of the present invention and the comparative example were recorded on an ink jet printer (YHP: D
A test pattern was printed using the Esk Writer C), and the results shown in Table 1 below were obtained.

[Table 1] The evaluation in Table 1 was performed according to the following criteria. After printing the dryness test pattern, the dryness of the surface was judged by touch with a finger. ⊚: Dry within 1 minute after printing. ◯: Dry in 1 to 2 minutes after printing. Δ: Dry 2 to 3 minutes after printing. X: Does not dry in 3 minutes after printing. After printing the image quality test pattern, the state of the dots in the image was visually determined. ⊚: There is no ink bleeding or runoff, and a suitable dot spread is shown. ◯: There is no ink bleeding or runoff, but the appropriate dot spread is small. Δ: There is slight ink bleeding, but there is no runoff and the appropriate spread of dots is large. X: Ink bleeds and flows out significantly. Thirty minutes after printing the water resistance test pattern, water droplets were dropped on the surface, and immediately after that, the surface was lightly rubbed with a fingertip and the change in the receiving layer was visually observed. ⊚: No change. B: Bleeding is recognized in a very small part. Δ: Ink stain is recognized on the receiving layer. X: Ink oozes out before touching with a fingertip.

[0032]

Since the present invention is configured as described above, it has the effects described below.
Since the ink is quickly absorbed in the receiving layer, the drying is fast, there is a suitable spread of dots without unevenness in the image, and recording with excellent color reproducibility is possible. Further, since the recording sheet of the present invention has good transparency and excellent water resistance, it can be suitably used for applications such as OHP sheets.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing a cross-sectional structure of the present invention.

[Explanation of symbols]

1 base material sheet 2 ink receiving layer A recording sheet

Continued Front Page (72) Inventor Shunichi Ebihara 1-1-1, Ichigayakacho, Shinjuku-ku, Tokyo Dai Nippon Printing Co., Ltd.

Claims (5)

[Claims] 1. A recording sheet in which an ink receiving layer comprising a polymer composition and a filler is provided on at least one surface of a base sheet, wherein the filler has two or more kinds of fine particles having different dye fixing properties. A recording sheet, which is a mixture of 2. A recording sheet, wherein the filler according to claim 1 is selected from organic ultrafine particles, silica sol and alumina sol. 3. A recording sheet, wherein the filler according to claim 1 is in the range of 20 to 500% by weight based on the solid content of the polymer composition. 4. A recording sheet, wherein the polymer composition according to claim 1 is polyvinyl alcohol and its cation modified product, polyvinyl acetal, acrylic resin and its cation modified product, or a mixture thereof. 5. The ink receiving layer according to claim 1, wherein the silica powder having a particle size of 5 to 20 μm is contained in the range of 0.1 to 5% by weight based on the solid content of the polymer composition. And a recording sheet.