JP2693117B2 - Recording sheet - Google Patents

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 which can be commonly used for an output machine which is commonly used in offices and homes such as ink jet, PPC, and thermal fusion transfer.

[0002]

2. Description of the Related Art Conventionally, recording sheets suitable for printing means such as thermal fusion transfer, PPC, pen plotter, ink jet, etc. have been proposed as recording sheets. For example, as a material for inkjet recording, in addition to ordinary paper, a material having a porous surface or an ink receiving layer made of a water-soluble resin such as polyvinylpyrrolidone, polyvinyl alcohol, or gelatin is used on the surface of the paper. . Such an ink jet recording paper is
Good absorption of ink and water resistance are required. Therefore, a graft copolymer and / or a block copolymer is used as a resin for the ink receiving layer to satisfy both water absorption and water resistance. Has been proposed (Japanese Patent Laid-Open No. 61-21780).

However, such a block copolymer takes a lot of time and labor for the polymerization method, and has not yet obtained a sufficiently satisfactory performance. In addition, in order to have water resistance and hydrophilicity, hydrophilic polyvinylpyrrolidone (hereinafter referred to as PVP) as a resin for the ink receiving layer and a (meth) acrylic acid type polymer which is an acidic component are blended (Japanese Patent Laid-Open No. Sho 6-96).
No. 2-218181), and those using a specific polymer of (meth) acrylic acid as a resin for the ink receiving layer (JP-A-62-222884, JP-A-63-17).
However, there is a problem in that the (meth) acrylic acid-based polymer alone has poor ink absorptivity and an extremely slow ink drying speed. In addition, acidic (meth) acrylic acid type polymers have poor compatibility with PVP when mixed with PVP, making it difficult to form a uniform coating film, and it is easy to adjust the physical properties of the coating film. There is a difficulty that you cannot do it.

By the way, generally, the ink receiving layer of the ink jet recording material has been treated to absorb and retain only the aqueous ink, but in recent years, hydrophilic resin and lipophilic resin have been used as the resin of the ink receiving layer. By blending, a material that can be used for both inkjet and PPC (electrophotographic copying machine) has been proposed (Japanese Patent Laid-Open No. 5-1779).
No. 21). The ink receiving layer of such a recording paper is
Although toner adhesion is imparted in addition to water-based ink absorbency and water resistance, a general-purpose recording paper for heat-sensitive melt transfer and recording by a pen plotter has not yet been proposed.

The present invention has been made in view of such drawbacks of the conventional recording paper, and has the performance required as an inkjet recording paper, and further includes PPC, heat-sensitive fusion transfer,
The purpose is to provide a recording sheet that can be shared with pen plotters and the like.

[0006]

The recording paper of the present invention which achieves such an object comprises a base material and an ink receiving layer provided on at least one surface of the base material. The resin component uses polyvinylpyrrolidone as a hydrophilic resin and a basic (meth) acrylic acid ester copolymer composed of at least four kinds of monomers as a lipophilic resin.

As the base material, ordinary paper, tracing paper, coated paper, plastic film such as polyester, cloth and the like can be appropriately selected and used according to the application. When the recording paper is used as an original drawing or for OHP, a substantially transparent substrate such as a plastic film is used. Further, as a base material that replaces the tracing paper, a base material obtained by adhering Japanese paper to one side or both sides of a plastic film is preferably used. Such a base material has flatness and dimensional stability against moisture and heat during storage, and is excellent in writability. The Washi paper to be attached to the plastic film preferably has a basis weight of about 6 to 29 g / m ² . When Japanese paper is attached to a plastic film, urea resin-based, phenol-based, resorcinol-based, epoxy-based, urethane-based, polyester-based, acrylic-based, etc. adhesives may be used.

The thickness of the base material is not particularly limited as long as it has a thickness (for example, 38 to 250 μm) necessary for recording paper. The ink receiving layer is provided on one side or both sides of such a substrate, contains a hydrophilic resin and a lipophilic resin as a resin component, and preferably contains a matting agent.

Polyvinylpyrrolidone is used as the hydrophilic resin, and a basic (meth) acrylic acid ester copolymer composed of at least four kinds of monomers is used as the lipophilic resin. Polyvinylpyrrolidone is a hydrophilic resin, and is generally insoluble or hardly soluble in organic solvents used in oil-based inks used for pen plotters such as toluene, xylene, ketones, and esters. Even when recording is performed, the coating film is unlikely to be damaged and good recording can be performed. Furthermore, it has excellent ink absorption and color development for water-based inks such as inkjet.
In particular, by combining with a (meth) acrylic acid ester copolymer which will be described later, it is possible to improve the performance required as an inkjet recording paper, for example, ink adsorption, water resistance, weather resistance and the like.

Polyvinylpyrrolidone having a molecular weight of 100,000 or more, preferably 300,000 to 1,500,000 is used.
When the molecular weight is less than 100,000, the coating property is low and it is difficult to form a coating film. On the other hand, if it exceeds 1.5 million, the viscosity of the polymer solution becomes too high, and the leveling property of the coating film formed becomes unfavorable. The content of polyvinylpyrrolidone varies depending on the monomer composition of the (meth) acrylic acid ester copolymer described later, but the lower limit is 10% or more, preferably 50% or more of the resin component, and the upper limit is 90%.
% Or less, preferably 80% or less. With such a range, both the water resistance and the water absorption performance of the ink receiving layer can be satisfied.

The basic (meth) acrylic acid ester copolymer, which is a lipophilic resin, contains at least 2-hydroxyethyl (meth) acrylate (HEMA or HEA) and 2-dimethylaminoethyl methacrylate (DMMA). A copolymer of at least quaternary or more composed of a hydrophilic monomer containing and a water resistant (lipophilic) monomer containing at least methyl methacrylate (MMA) and n-butyl methacrylate (BMA). As long as they do not impair the characteristics of individual monomers in the invention, those having 5 or more elements can be used.

By using the basic (meth) acrylic acid ester copolymer as described above, the adhesiveness of the toner and the compatibility with polyvinylpyrrolidone can be enhanced. In addition, by combining at least two types of hydrophilic monomers and at least two types of water-resistant monomers into a quaternary or more, the compounding ratio of these monomers is appropriately selected to adjust the balance between hydrophilicity and water resistance. You can
Moreover, it becomes easy to adjust other properties such as physical properties of the coating film.

The ratio of the hydrophilic monomer to the water-resistant (lipophilic) monomer is about 1: 1 in terms of molar ratio, preferably, the content of the hydrophilic monomer (DMMA and HEMA or HEA) is 30 to 30 with respect to the total amount of the monomers. 70 mol%, preferably 40-60 mol%, more preferably 45-50 mol%
And When the amount of the hydrophilic monomer is too large, the adsorbing power of the ink is increased when mixed with PVP, but the coating film is easily dissolved even if the mixing ratio with PVP is adjusted, and the drying property of the ink is deteriorated. If the hydrophilic monomer content is 70 mol% or more, P
Adhesion of the PC toner deteriorates. On the other hand, when the amount of the lipophilic monomer is too large, the compatibility with PVP is reduced, the ink absorption speed is deteriorated, and the drying speed is decreased.

The hydrophilic monomer comprises at least DMMA and HEMA or HEA. Of the hydrophilic monomers, DMMA is a component that contains an amino group and makes the polymer basic, and can improve the ink absorption and adsorption. As a result, the weather resistance and the resolution can be improved, the color developability can be improved, and the adhesiveness between the toner binder of the PPC and the ink of the thermal melting transfer ribbon can be improved. Further, by using DMMA, the compatibility between the copolymer and polyvinylpyrrolidone can be increased.

On the other hand, the hydrophilic monomer HEMA or H
EA can improve water resistance without impairing hydrophilicity, and either one or both of HEMA and HEA can be used together. The molar ratio of DMMA to HEMA or HEA is in the range of 3: 1 to 1: 3, preferably 2: 1 to 1: 2. By setting it in such a range, it is possible to enhance the adhesiveness to the toner or the melted ink and the adsorptivity of the water-soluble ink, and to maintain an appropriate ink drying rate.

The lipophilic monomer is composed of at least MMA and BMA. Addition of MMA and BMA can improve the water resistance of the ink receiving layer and can maintain an appropriate hardness of the coating film. Therefore, by adding these lipophilic monomers, it is possible to impart the performance such as scratch resistance required for the recording paper for pen plotters. Among these lipophilic monomers, the molar ratio of MMA to BMA is 10: 1 to 2:
1, preferably 5: 1 to 4: 1. By setting the content in such a range, even if both are mixed, blocking does not occur, and the hardness of the coating film can be kept optimum.

In addition, lipophilic monomers such as ethyl (meth) acrylate (EMA) and 2-hydroxypropyl (meth) acrylate (HP) within a range that does not impair these performances.
A hydrophilic monomer such as MA) or 2-hydroxybutyl (meth) acrylate can be used in combination. Further, if necessary, a second ink receiving layer having a larger ink absorption amount than the first ink receiving layer can be formed between the substrate and the ink receiving layer (hereinafter referred to as the first ink receiving layer). The second ink receiving layer is for absorbing a large amount of the ink rapidly absorbed by the first ink receiving layer without causing the ink to overflow, and preventing a decrease in the absorption speed of the first ink receiving layer. That is, when a substance having a small ink absorption amount is used, the ink absorbed by the first ink receiving layer cannot be completely absorbed in the lower layer and the drying of the ink is delayed, or the ink penetrates and diffuses more than necessary in the lateral direction. This is because the resolution of the recorded image is reduced and it becomes impossible to form a high quality recorded image.

The second ink receiving layer satisfying the above requirements has a swelling property with respect to the water-based ink and is composed of a water-soluble or hydrophilic resin which is not dissolved or swollen when the first ink receiving layer is formed. Is preferred. Such resins include albumin, gelatin, casein, starch,
Natural resins such as gum arabic and sodium alginate, carboxymethyl cellulose, hydroxyethyl cellulose,
Synthesis of polyamide, polyacrylamide, polyhydroxyethylmethacrylate, polyphenylacetoacetal, polyethyleneimine, polyvinylpyrrolidone, polyvinylpyridinium halide, melamine resin, polyurethane, polyvinyl alcohol, polyester, polyacrylic acid soda, acrylic acid ester copolymer Resins may be mentioned, and one or more of these may be mixed and used. Particularly, polyvinyl alcohol is preferable in terms of absorbability and film forming property. Further, it is possible to use other resins together for improving the adhesion to the support, the film forming strength, and the like.

The polyvinyl alcohol preferably used in the second ink receiving layer preferably has a higher degree of saponification in order to increase the ink absorbability, but it can suppress stickiness due to moisture absorption of the coating film, In addition, 70% or more, preferably 90% or more is used to maintain the necessary hydrophilicity. As the thickness of the first ink receiving layer,
Although it cannot be generally stated depending on the amount of ink and the type of resin used, it is usually 5 to 50 μm, preferably 10 to 20 μm.
Is preferred. The reason why the thickness is 5 μm or more is that the ink adsorbability can be maintained, while the reason that the thickness is 50 μm or less is that curling can be prevented.

The recording paper of the present invention is preferably matted in order to impart writability. Therefore, the base material itself may be matted, a matting agent may be added to the resin forming the ink receiving layer, or both may be used in combination. As a matting method, when the substrate is a plastic film, known methods such as a sandblast method, a chemical matting method, and a method of adding a matting agent can be adopted.

Particularly, in the ink receiving layer of the present invention, the ink absorbing property of the ink receiving layer can be enhanced by adding a matting agent. Known matting agents such as silica (non-crystalline silica), clay, talc, diatomaceous earth, calcium carbonate, calcium sulfate, barium sulfate, aluminum silicate, titanium oxide, zinc oxide, synthetic zeolite, and alumina. Besides, smectite can be used, and these matting agents can be used alone or in combination of two or more kinds.

Among these matting agents, smectite is particularly preferable in terms of transparency and ink absorbability. Smectite has a layered structure with a small number of exchangeable cations between layers,
Usually, since it has two water molecule layers, it is easy to adsorb water molecules, and the ink absorbability especially during ink jet recording is remarkably improved. Further, since the surface area value is large (about 600 m ² / g in hectorite), it is effective also in that respect to enhance the ink absorbability. Furthermore, smectite has a much smaller particle size than known matting agents (about 1 in the thickness direction of the layer).
Since the thickness is 0 angstrom and μ order in the plane direction), even if added, the haze value (HAZE) does not increase, and a clear coating film having a high transmission density can be obtained. Therefore, it is particularly suitable when the recording sheet of the present invention is used for OHP or as the second original drawing.

The amount of matting agent added is usually 100% resin.
In contrast, it is about 5 to 200 parts. If the amount added exceeds 200, the binding ability of the resin will be lost, which is not preferable. In addition to the matting agent, the ink receiving layer of the present invention may contain additives such as a leveling agent, an ultraviolet absorber and an antioxidant. In particular, the addition of an ultraviolet absorber is preferable because it can withstand use as an outdoor display.

The recording paper of the present invention is prepared by dispersing or dissolving the above-mentioned resin, matting agent and other additives constituting the ink receiving layer in a suitable solvent, and coating and drying on one side or both sides of the substrate. Form. As the solvent, propylene glycol monomethyl ether, methylene glycol monomethyl ether, ethyl alcohol,
Methyl alcohol, isopropyl alcohol, etc. are used. The thickness of the ink receiving layer is not particularly limited,
Usually, it is about 0.1 to 50 μm, preferably about 1 to 20 μm. If it exceeds 50 μm, the absorption of ink is absorbed only on the surface of the recording layer, and a sufficient ink density cannot be obtained.

1 (a) to 1 (c) exemplify the structure of the recording paper of the present invention, in which (a) is a substrate 1 having an ink receiving layer 2 provided on one side thereof, (b) and (b). c) is provided on both sides. When the ink receiving layer 2 is provided on one surface of the base material 1, a back coat layer 3 for preventing curling, improving transportability, preventing electrification, etc. is formed on the opposite surface of the base material 1 as necessary.
Can be provided. The back coat layer 3 may also have a traceability, and examples of the material of the back coat layer 3 include polyurethane resin, cellulose resin, acrylic resin, water-soluble resin and the like.

When a plastic film is used as the substrate 1, a primer layer (not shown) is previously formed on the film surface of the layer in order to enhance the adhesiveness with the ink receiving layer 2 (and the back coat layer 3). ) Is preferably formed in advance. A plastic film that has been subjected to easy adhesion treatment may be used. Examples of the resin for the primer layer include polyester resin, vinylidene chloride, acrylonitrile, and acrylic resin.

When a plastic film 10 such as a polyester film to which Japanese paper or tracing paper 11 is adhered is used as the base material 1, the Japanese paper or tracing paper 11 is not provided with such a primer layer. The ink receiving layer 2 can be directly provided on the surface (FIG. 1 (c)). The recording paper of the present invention configured as described above can be used for ink jet recording, heat-sensitive fusion transfer recording, P
It has excellent fixability to ink and toner of recording means such as PC, and also has excellent absorbability and fixability of water-based or oil-based ink in recording means such as plotter, and also has water resistance and appropriate hardness of coating film. Since it has the physical properties described above and is excellent in ink absorbency, dryness, and color development for inkjet recording, it can be used as a recording sheet for these recording means.

[0028]

Embodiments of the present invention will be described below. In Examples 1 to 3 and Comparative Example 3, the (meth) acrylic acid ester copolymer was 45 mol% MMA, 10 mol% BMA, 30 mol% HEMA, and 15 mol% DMMA. A copolymerized product was used. Example 1 A polyester film (Lumirror S-14:
Toray Co., Ltd.) was used to apply a coating liquid for the ink receiving layer having the following formulation to the surface of the substrate with a bar coater so as to have a dry thickness of 8 μm, followed by drying to prepare a recording paper.

PVP (K-90: manufactured by ISP) 3 parts by weight (meth) acrylic acid ester copolymer 2 parts by weight Methyl cellosolve 45 parts by weight This recording paper is printed with an inkjet printer (DESKJET 50).
0J: Hewlett-Packard Company, PPC (RICOPY F
T-5500: manufactured by Ricoh Co., Ltd., heat-sensitive fusion transfer device (Oasis 30)
LXII: manufactured by Fujitsu Limited and color plotter (FPG-30)
(0: manufactured by Fujitsu Ltd.) was recorded, and performance such as ink receptivity was examined. As a result, the ink-jet ink was dried at a good rate, and the printing was obtained with practically no problem with the adhesiveness of the PPC toner and the adhesiveness of the molten ink. Good printing was also obtained with a color plotter.

Comparative Example 1 A polyester film (Lumirror S-14:
Toray Co., Ltd.) was used to apply a coating liquid for the ink receiving layer having the following formulation to the surface of the substrate with a bar coater so that the dry thickness was 8 μm, and a recording paper was prepared. In addition, performances such as ink receptivity were investigated.

PVP (K-90: manufactured by ISP) 3 parts by weight Styrene-acrylic acid copolymer 2 parts by weight Methyl cellosolve 45 parts by weight As a result, the drying speed of the inkjet ink was slower than that of the recording paper of Example 1, Further, the adhesiveness between the toner and the molten ink was inferior to that in Example 1.

Comparative Example 2 A polyester film (Lumirror S-14:
Toray Co., Ltd.) was used to apply a coating liquid for the ink receiving layer having the following formulation to the surface of the substrate with a bar coater so that the dry thickness was 8 μm, and a recording paper was prepared. In addition, performances such as ink receptivity were investigated.

PVP (K-90: manufactured by ISP) 3 parts by weight MMA polymer 2 parts by weight (Paraloid A-11: Rohm & Haas Co.) methyl cellosolve 45 parts by weight As a result, the drying speed of the inkjet ink was determined as in Example 1. The recording paper was slower than the recording paper of Example 1, and the adhesive properties of the toner and the molten ink were inferior to those of Example 1.

Comparative Example 3 A polyester film (Lumirror S-14:
Toray Co., Ltd.) was used to apply a coating liquid for the ink receiving layer having the following formulation to the surface of the substrate with a bar coater so that the dry thickness was 8 μm, and a recording paper was prepared. In addition, performances such as ink receptivity were investigated.

(Meth) acrylic acid ester copolymer 5 parts by weight Methyl cellosolve 45 parts by weight As a result, the drying speed of the inkjet ink was extremely low, and the ink was hardly absorbed. Example 2 A polyester film (Lumirror S-14:
Toray Co., Ltd.) was used to apply a coating liquid for the ink receiving layer having the following formulation to the surface of the substrate with a bar coater so as to have a dry thickness of 8 μm, followed by drying to prepare a recording paper.

PVP (K-90: manufactured by ISP) 3 parts by weight (meth) acrylic acid ester copolymer 2 parts by weight amorphous silica 4 parts by weight (Mizukasil P78A: manufactured by Mizusawa Chemical Co., Ltd.) Methyl Cellosolve 81 parts by weight Inkjet printer for recording paper (DESKJET 50
0J: Hewlett-Packard Company, PPC (RICOPY F
T-5500: manufactured by Ricoh Co., Ltd., heat-sensitive fusion transfer device (Oasis 30)
LXII: manufactured by Fujitsu Limited and color plotter (FPG-30)
(0: manufactured by Fujitsu Ltd.) was recorded, and performance such as ink receptivity was examined. As a result, the ink-jet ink dried at a high speed and did not cause blocking. Also, the adhesiveness of the PPC toner and the adhesiveness of the molten ink were good, and good printing was obtained in terms of fine lines, color reproduction, and the like in the plot by a color plotter. Example 3 A polyester film (Lumirror S-14:
Toray Co., Ltd.) was used to apply an ink receiving layer coating solution having the following formulation to the surface of the substrate with a bar coater to a dry thickness of 8 μm and then dried. A recording paper was prepared.

PVP (K-90: manufactured by ISP) 3 parts by weight (meth) acrylic acid ester copolymer 2 parts by weight Synthetic smectite 4 parts by weight (SWN: manufactured by Corp Chemical) Methyl Cellosolve 81 parts by weight This recording paper is used. Inkjet printer (DESKJET 50
0J: Hewlett-Packard Company, PPC (RICOPY F
T-5500: manufactured by Ricoh Co., Ltd., heat-sensitive fusion transfer device (Oasis 30)
LXII: manufactured by Fujitsu Limited and color plotter (FPG-30)
(0: manufactured by Fujitsu Ltd.) was recorded, and performance such as ink receptivity was examined. As a result, the ink-jet ink dried at a very high speed, and no blocking occurred. Also PP
The adhesiveness of the C toner and the adhesiveness of the molten ink were also good, and good printing was obtained in terms of fine lines, color reproduction, and the like in the plot by a color plotter. Comparative Example 4 A polyester film (Lumirror S-14:
Toray Co., Ltd.) was used to apply a coating liquid for the ink receiving layer having the following formulation to the surface of the substrate with a bar coater so that the dry thickness was 8 μm, and a recording paper was prepared. In addition, performances such as ink receptivity were investigated.

3 parts by weight of PVP (K-90: manufactured by ISP) 2 parts by weight of styrene-acrylic acid copolymer (John Kryl 586: manufactured by Johnson Polymer Co., Ltd.) 4 parts by weight of amorphous silica (Mizukasil P78A: Mizusawa Chemical Co., Ltd.) Methyl Cellosolve 81 parts by weight As a result, the ink-jet ink drying rate was high, but the adhesiveness of the PPC toner and the adhesiveness of the molten ink were extremely poor. Example 4 A polyester film (Lumirror S-14:
Toray Co., Ltd.) was used to apply a coating liquid for the ink receiving layer having the following formulation to the surface of the substrate with a bar coater so that the dry thickness was 8 μm, and a recording paper was prepared. In addition, performances such as ink receptivity were investigated. Incidentally, as the (meth) acrylic acid ester copolymer, 42 mol% of MMA,
BMA of 8 mol%, HEMA of 25 mol%, DMMA of 15 mol%, EMA of 5 mol%, and HPMA of 5 mol% were used for the copolymerization.

PVP (K-90: manufactured by ISP) 3 parts by weight (meth) acrylic acid ester copolymer 2 parts by weight Methyl cellosolve 45 parts by weight As a result, as in Example 1, the drying speed of the inkjet ink was good. In other words, the printability was practically satisfactory with respect to the adhesiveness of the PPC toner and the adhesiveness of the molten ink. Good printing was also obtained with a color plotter.

[0040]

As is apparent from the above examples, according to the present invention, polyvinylpyrrolidone is used as a resin for the ink receiving layer in combination with a basic (meth) acrylic acid ester copolymer containing a specific monomer. By doing so, it is possible to obtain a recording paper that is excellent in ink-jet ink absorbency and dryness, and that is also water resistant and weather resistant. In particular, by adding a matting agent to these resins, the ink absorbency can be significantly improved. Further, according to the present invention, it is possible to obtain a recording paper which has good adhesion to PPC toner and molten ink as well as ink jet, and has performances required for a pen plotter such as scratch resistance. Furthermore, according to the present invention, by using a specific matting agent, it is possible to provide a recording sheet which is transparent and can be used as an original drawing.

[Brief description of the drawings]

FIG. 1 is a diagram showing a structure of a recording sheet of the present invention.

[Explanation of symbols]

 1 ... Base material 2 ... Ink receiving layer 11 ... Japanese paper

Claims (1)

(57) [Claims] 1. A base material and an ink receiving layer provided on at least one surface of the base material, wherein the ink receiving layer contains 10 to 90% by weight of polyvinylpyrrolidone as a resin component, and at least two kinds. Basic (meth) consisting of a hydrophilic monomer and at least two lipophilic monomers
A recording sheet containing an acrylic ester copolymer.