JP2002160440A - Ink jet recording paper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet recording paper, which can apply to both a dye-based ink and a pigment-based ink, is excellent in an image density, simultaneously develops no blur in an image and, at the same time, suppresses the development of a cockling. SOLUTION: In the ink jet recording paper, which is produced by providing an ink accepting layer on a base material, a paper having a density of 0.6 to 1.1 g/cm3 and a basis weight of 120 to 250 g/m2 is employed as a base material. At the same time, the ink accepting layer includes an acrylamide- diallylamine copolymer material and a dimethylamine-epichlorohydrin copolymer material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink-jet recording sheet, and more particularly, to an ink-jet recording sheet having an ink-receiving layer on a substrate, which can be applied particularly to both dye-based inks and pigment-based inks and has excellent image density. Also, there is no bleeding of the image,
The present invention also relates to an ink jet recording sheet in which cockling (undulation or wrinkling) is suppressed.

[0002]

2. Description of the Related Art In recent years, with the widespread use of computer technology, materials created by computers have been frequently printed out using a printer or the like. As a printer used at that time,
A dot impact printer, a laser printer, a thermal printer, an ink jet printer, and the like can be mentioned, but an ink jet printer is widely used because there is almost no mechanical noise at the time of printout and the running cost associated with the printout is low. In addition, by using an ink for an ink jet printer or an ink jet plotter as a pigment ink, printouts have been exhibited indoors or outdoors for a long period of time. In the ink jet recording sheet used in this ink jet printer, the unfavorable phenomenon called cockling, in which waviness and wrinkles are caused due to non-uniform volume change caused by absorbing water and solvent in the ink in the past. Often occurred. Therefore, development of an ink jet recording sheet free of such cockling has been desired.

Further, in the ink jet recording system, a dye-based ink containing a dye is used as a coloring material. In response to this, the coloring property of the printing portion and the fixing property of the ink are improved, and the bleeding of the ink is improved. In order to suppress this, ink jet recording sheets in which various ink receiving layers are provided on a substrate have been devised. For example, those in which the ink receiving layer contains a dye fixing agent, those containing a resin that absorbs the solvent and moisture of the ink, and those that provide fine voids on the surface to absorb the ink are used. On the other hand, in recent years, pigment-based inks containing a pigment as a coloring material have also been used, and since these pigment-based inks have different properties from dye-based inks, various inkjet recording sheets applicable to the pigment-based inks have been developed. .

Further, in order to improve user's convenience, an ink jet recording sheet applicable to both dye-based ink and pigment-based ink has been developed. For example, an ink jet recording sheet is disclosed in which a receiving layer for fixing a dye-based ink and a receiving layer for fixing a pigment-based ink are laminated (Japanese Patent Application Laid-Open No. 10-119417). However, it is not easy to produce both a dye-based ink and a pigment-based ink having excellent image density and no image bleeding. Further, in addition to the above, the fact is that an ink jet recording sheet that suppresses the occurrence of cockling and sufficiently satisfies all the conditions has not yet been found. In addition, for the purpose of cost reduction,
It is very difficult to accommodate both types of ink with one layer without providing a separate receiving layer.

[0005]

In this situation, the present invention can be applied to both dye-based inks and pigment-based inks, and has excellent image density, no image bleeding, and cockling. It is an object of the present invention to provide an ink jet recording sheet in which occurrence of ink is suppressed.

[0006]

Means for Solving the Problems The present inventor has conducted intensive studies to develop an ink jet recording paper having the above-mentioned excellent functions, and as a result, a base material having a density and a basis weight within a predetermined range. And that an ink-receiving layer containing a specific copolymer is provided thereon, which is suitable for the purpose. The present invention has been completed based on such findings. That is, the present invention provides an ink jet recording paper having an ink receiving layer provided on a base material, wherein the base material has a density of 0.6 to 1.1 g / cm ³ ,
An ink jet recording sheet using a paper having a basis weight of 120 to 250 g / m ² and an ink receiving layer containing an acrylamide / diallylamine copolymer and a dimethylamine / epichlorohydrin copolymer. It is.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The ink jet recording paper of the present invention has an ink receiving layer on at least one surface of a substrate. In the present invention, paper is used as the base material. As this paper, a normal paper using pulp as a main raw material is used, but as long as the conditions of the present invention are satisfied,
It may contain a substance other than pulp such as chemical fiber. Suitable papers include high quality papers, art papers, coated papers and the like. The substrate used in the present invention has a density of
0.6 to 1.1 g / cm ³ . This density is 0.6 g / cm
^If it is less than ³ , cockling is likely to occur, and 1.1
If it exceeds g / cm ³ , bleeding tends to occur in both the dye-based ink and the pigment-based ink, but in particular, bleeding is more likely to occur in the pigment-based ink. Accordingly, the preferred density is in the range of 0.8~1.0g / cm ^3. Further, the base material needs to have a basis weight in a range of 120 to 250 g / m ² . If the basis weight is less than 120 g / m ² , cockling tends to occur, while 250 g / m ²
If it exceeds m ² , the rigidity becomes too high, the flexibility of the ink jet recording paper is reduced, and handling is hindered. For these reasons, the preferred basis weight is 120-200 g /
m ² .

In the present invention, the ink receiving layer provided on at least one surface of the base material includes an acrylamide / diallylamine copolymer (hereinafter, sometimes referred to as an acrylamide resin) and dimethylamine / epichlorohydroxide. It is necessary to contain a phosphorus copolymer (hereinafter, sometimes referred to as epichlorohydrin-based resin). By using the base material and including both the acrylamide-based resin and the epichlorohydrin-based resin, the image density is improved for both the dye-based ink and the pigment-based ink, and the image bleeding is prevented. And the occurrence of cockling can be suppressed. Although the reason for this is not necessarily clear, it is assumed that the reason is that the time required for fixing the pigment and the dye and for absorbing the solvent is appropriately balanced.

The content of the acrylamide / diallylamine copolymer and the content of the dimethylamine / epichlorohydrin copolymer in the ink receiving layer is preferably 1 to the total solid weight of the ink receiving layer in view of the above effects. The range is preferably from 20 to 20% by weight, and particularly preferably from 3 to 15% by weight. The ink receiving layer usually contains a binder resin and a filler. Examples of the binder resin include polyvinyl alcohol, polyvinyl butyral, gelatin, polyvinyl acetal, carboxymethyl cellulose, polyvinyl pyrrolidone, styrene-acryl copolymer, ethylene-vinyl acetate copolymer, styrene-butadiene rubber, polyurethane resin, acrylic resin, and the like. Is mentioned. These may be used alone or in a combination of two or more. The content of the binder resin in the ink receiving layer is preferably in the range of 10 to 30% by weight based on the total solid weight of the ink receiving layer. If the content is less than 10% by weight, the strength of the ink receiving layer may be insufficient, and if it exceeds 30% by weight, image bleeding may occur. Considering the strength of the ink receiving layer and the bleeding of the image, the more preferable content of the binder resin is in the range of 15 to 25% by weight.

On the other hand, the filler is a water-insoluble filler such as silica, synthetic and natural zeolite, calcium carbonate, magnesium carbonate, diatomaceous earth, talc, titanium oxide,
Examples include white carbon, kaolin clay, calcined clay, and organic pigments, and these can be used alone or as a mixture. In particular, silica is preferred from the viewpoints of ink fixability, suppression of bleeding, and ink absorption ability. As the filler, one kind may be used alone, or two or more kinds may be used in combination. The content of the filler in the ink receiving layer is usually 40% based on the total solid weight of the ink receiving layer.
It is in the range of ％ 80% by weight, preferably 50-70% by weight.

In the present invention, the ink receiving layer includes:
Various additives such as a surfactant, an antistatic agent, and an ultraviolet absorber can be contained, if necessary, as long as the object of the present invention is not impaired. This ink receiving layer is usually 3
-20 g / m ² , preferably 5-15 g / m ² . In the present invention, in order to form an ink receiving layer on a substrate, first, the acrylamide-based resin, epichlorohydrin-based resin, filler, binder resin and various additives used as necessary, It is dissolved or dispersed in an aqueous solvent to prepare a coating liquid having a solid concentration suitable for coating. Then, this coating liquid, on one or both surfaces of the substrate, spray method, dipping method, or using a known device such as an air knife coater, bar coater, roll coater, the thickness after drying becomes a predetermined value By coating and drying as described above, a desired ink receiving layer can be formed. The above-mentioned drying treatment is carried out by a usual method such as hot-air drying, for example, 100 to 12 days.
It is preferable to carry out at a temperature of about 0 ° C. Note that an anchor layer can be provided between the substrate and the base material.

In the present invention, when the ink receiving layer is provided on one side of the base material, a mat layer or an ink receiving layer may be provided on the back surface (the surface opposite to the ink receiving layer) of the base material, if desired. it can. The mat layer is formed by a binder and a matting agent, and as the binder,
For example, there are thermoplastic resins, thermosetting resins, photocurable resins, and the like. Specific examples include acrylic, urethane, polyester, and vinyl chloride resins. As the matting agent, for example, silica, zirconia, clay, kaolin, alumina, titania, zeolite, calcium carbonate, barium sulfate, magnesium hydroxide, calcium phosphate, inorganic powders such as glass, acrylic resin, urethane resin, Synthetic resin powders such as vinyl chloride resin, benzoguanamine resin, and benzoguanamine / melamine / formaldehyde condensate are exemplified. The average particle size of this matting agent is 0.1 to 20 μm, preferably 2 to 10
The range of μm is preferred. When the ink receiving layer is also formed on the back surface of the base material, the same material as that provided on the front surface of the base material may be provided, or another material, for example, containing no matting agent, or A transparent ink receiving layer containing a small amount may be provided. The thickness of the mat layer is advantageously in the range of 1 to 10 μm, preferably 3 to 7 μm, from the viewpoint that curl prevention and good writability are obtained. Further, the mat layer may contain those conventionally used as additives, for example, a surfactant, a lubricant, a stabilizer, and a colorant.

[0013]

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. In addition, the performance of the produced inkjet recording paper was evaluated according to the following procedure. (1) Image Density The image density of the portion printed with magenta ink was measured with a Macbeth reflection densitometer RD-918. (2) Image bleeding Continuous printing of blue (mixed color of cyan and magenta) and yellow is performed, and the bleeding degree of the ink at the boundary is determined.
Evaluation was made according to the following criteria. ：: no ink bleeding Δ: Some bleeding of the ink was observed. X: Ink bleeding is large. (3) Cockling Solid printing of blue (mixed color of cyan and magenta), red (mixed color of magenta and yellow), and green (mixed color of cyan and yellow) was performed, and the degree of cockling was evaluated according to the following criteria. . ：: Cockling is small and there is no practical problem. ×: Cockling is large and there is a problem in practical use.

Example 1 A filler containing 8% by weight of an inorganic filler and having a basis weight of 128 g / m 2
^In Example ² , ^high quality paper having a density of 0.85 g / cm ³ was used as a base material. On the other hand, synthetic amorphous silica [“Mizukasorb C-1” manufactured by Mizusawa Chemical Industries, solid content 100% by weight] 100
Parts by weight, 35 parts by weight of a silanol group-modified polyvinyl alcohol [“Kuraray R Polymer R1130” manufactured by Kuraray Co., Ltd., solid content 100% by weight], an acrylamide-diallylamine copolymer [“SUMIREZ Resin 1 manufactured by Sumitomo Chemical Co., Ltd.”
001 ", solid content 30% by weight] 10 parts by weight, dimethylamine / epichlorohydrin copolymer [Showa Polymer Co., Ltd." Polyfix 700 ", solids content 60% by weight] 5 parts by weight, alumina sol [Nissan Chemical Industries "Alumina Sol 200", solid content 10% by weight] 7 parts by weight, fluorescent brightener [Bayer "Branco Four UW Liquid"] 1.3 parts by weight, nonionic surfactant [SN Deformer 480 manufactured by San Nopco Co.] 1.6 parts by weight of water and 126 parts by weight of water were homogeneously mixed to prepare a coating liquid A. Next, the coating liquid A was applied to one surface of the high-quality paper and dried to form an ink receiving layer of 8 g / m ² , thereby producing an ink jet recording paper.

Comparative Example 1 The procedure of Example 1 was repeated except that high-quality paper containing 8% by weight of an inorganic filler, a basis weight of 128 g / m ² and a density of 1.50 g / cm ³ was used. Similarly, an ink jet recording paper was produced. Comparative Example 2 In the same manner as in Example 1, except that 8 wt% of the inorganic filler was used as the base material, high-quality paper having a basis weight of 105 g / m ² and a density of 0.85 g / cm ³ was used. Inkjet recording paper was produced. Example 1 and Comparative Example 1
Each of the ink-jet recording papers obtained in Nos. 1 to 2 was printed with a color ink-jet printer using a commercially available dye-based ink and a color ink-jet printer using a pigment-based ink, and the image density, image bleeding, and cockling were evaluated. Table 1 shows the results.

[0016]

[Table 1]

[0017]

According to the present invention, ink jet recording which is particularly applicable to both dye-based inks and pigment-based inks, has excellent image density, has no image bleeding, and suppresses cockling. Paper can be provided.

Claims (2)

[Claims] 1. An ink jet recording paper comprising an ink receiving layer provided on a base material, wherein the base material has a density of 0.6.
~ 1.1 g / cm ³ , basis weight of 120 ~ 250 g / m ² , and the ink receiving layer contains acrylamide / diallylamine copolymer and dimethylamine / epichlorohydrin copolymer. Inkjet recording paper. 2. The method according to claim 1, wherein the acrylamide
The content of the diallylamine copolymer and the dimethylamine / epichlorohydrin copolymer is 1 to 20% by weight based on the total solid weight of the ink receiving layer.
The ink jet recording paper according to the above.