JP3960297B2 - Inkjet recording medium - Google Patents

Description

  The present invention relates to an ink jet recording method for recording on a recording medium using water-based ink, and in particular, excellent reproducibility of high-definition images without damaging the texture of a substrate such as calibration paper such as fancy paper and newspaper. An ink jet recording medium having good fixability is provided.

  The ink jet recording method using water-based ink is suitable for terminal printers, facsimiles, POSs, form printings, etc. because of the low noise during recording, easy colorization, and high-speed recording. Application is underway. High-quality paper and coated paper used for general printing have poor ink absorbability, so the printed ink will not dry on the paper surface for a long time, contaminating the device and continuously printed sheets. Or the image becomes dirty, it is not practical. In order to solve these problems, a recording paper having a low sizing degree is used (for example, JP-A-52-53012), or a base paper in which urea-formalin resin is internally added is impregnated with a water-soluble polymer (for example, Japanese Patent Laid-Open No. 53-49113) has been proposed.

  On the other hand, with the improvement in performance of inkjet recording devices and the expansion of applications, such as higher speed, higher definition, and full color, the recording media are also required to have advanced characteristics, resulting in higher ink dot density. In addition, the color tone should be clear, and ink should not flow out or bleed even when the ink is absorbed quickly and the dots overlap. There is a demand for performance in which the diffusion of ink dots to the periphery does not become larger than necessary, and the dot shape is smooth and does not blur.

  Inks used for recording are mostly water-based inks that use water-soluble dyes, and when water is applied to the image formed on the recording medium, the dyes are redissolved and ooze out, which impairs the value of the recorded matter. In order to prevent this, a metal water-soluble salt is added to the recording surface (Japanese Patent Laid-Open No. 55-53591), and a polycation polymer electrolyte is contained on the surface of the recording medium (Japanese Patent Laid-Open No. 56-84992). In addition, techniques such as a technique for imparting a water-proofing agent that forms a lake with a dye in ink (Japanese Patent Laid-Open No. 55-150396) have been proposed. Further, a water-resistant agent having a specific molecular structure is selected for the purpose of obtaining superior water resistance and light resistance (Japanese Patent Laid-Open Nos. 59-33176, 60-49990, 61-61). No. 58788, etc.) have also been proposed. In addition, an improvement in light resistance by selecting quaternary ammonium hydroxide (Japanese Patent Laid-Open No. 59-198187) has been proposed. On the other hand, resolution and water resistance can be improved by applying a cationic surfactant to the substrate by a method such as internal addition or coating (Japanese Patent Laid-Open No. 56-99693).

  In order to obtain excellent printing performance, for example, recording paper (Patent Document 1, Patent Document 2, etc.) in which various porous inorganic pigments such as amorphous silica are coated on the surface has been proposed. The reproducibility of diameter, dot shape, dot density and color tone is improved. Many techniques for selecting the characteristics of such porous inorganic pigments have been disclosed.

For recording paper coated with porous pigments as described above, setting the coating amount is an important factor along with the characteristics of the porous inorganic pigment in order to obtain the desired printing performance. In this case, a coating amount of about 5 g / m ² or more is used. In this case, since the surface of the paper is coated with a porous pigment, it becomes matt and has a variety of properties utilizing the texture of the substrate. A recording medium could not be formed.

In order to leave the texture of plain paper, as a technique for adjusting the coating amount to a small value, the coating amount is set to 1 to 3 g / m ² and the critical surface tension of the recording layer surface is adjusted to between 32 dynes and 42 dynes. However, when using a base material that emphasizes texture, such as proof paper such as fancy paper or newspaper, the texture is improved. In order to leave it, it is desirable that the coating amount of the ink receiving layer is smaller. A preferable coating amount is less than 1.0 g / m ² , but generally ink absorbability is also lowered, so that ink jet recording suitability tends to deteriorate. Therefore, there is a recording medium (for example, Patent Document 4) having a printability with water-based ink and an appearance of plain paper by defining the Bristow water absorption of the base paper, and the coating amount is 0.5 to 5 g. Although it can be selected within the range of / m ² , there is a problem that an arbitrary substrate cannot be selected.

In addition, an ink jet paper having a color pigment dispersed by a surfactant in an ink receiving layer has been introduced as a printing proof paper (for example, Patent Document 5 and Patent Document 6), but the color pigment is contained in the ink receiving layer. Therefore, the color tone of the base material can be reproduced, but since the surface activity is used only for the purpose of dispersing the pigment, the film thickness of the ink receiving layer must be set to exhibit good ink absorption performance. 5 μm or more, preferably 10 μm or more is required, and the texture of the substrate cannot be reproduced.
JP-A-55-51583 JP-A-56-148585 JP 2002-46343 A JP-A-4-49086 JP 2002-292991 A JP 2002-225426 A

  The present invention is an ink jet recording method such as an ink jet printer, and the present invention is particularly excellent in ink absorption capability without damaging the texture and color tone of the base material, can print high quality images, and has high print density. An ink jet recording sheet free from bleeding is provided.

The present invention includes the following inventions.
(1) In an inkjet recording medium having an ink-receiving layer on a water-absorbing support, the ink-receiving layer has a porous pigment having an average particle size of 0.5 to 2.0 μm, a binder, and an HLB value of 10.0. The surfactant is contained in an amount of 10 to 30% by weight of the ink receiving layer, and the dry coating amount of the ink receiving layer is 0.2 to 1.0 g / m ^2. An ink jet recording medium characterized in that it is provided in the range described above.

  (2) The ink jet recording medium according to (1), wherein the water-absorbing support is paper having an ash value of less than 5% according to JIS-P8128.

  The ink receiving layer in the ink jet recording medium described in (1) and (2) above contains about 50 to 85% by mass of a 0.5 to 2.0 μm porous pigment and 10 to 45% by mass of a binder. It is preferable.

  The present invention provides an ink jet recording medium excellent in print density, print fineness, and texture reproducibility of a substrate.

  The ink receiving layer of the ink jet recording medium of the present invention preferably contains a pigment that is porous, has high ink absorbability, and enables clear color development as a porous pigment. As such pigments, synthetic silica, zeolite, calcium carbonate, calcium silicate, aluminum hydroxide, calcined clay, kaolin, clay, talc, white carbon, organic pigment (plastic pigment), etc. are generally used for paper coating. In particular, it is preferable to use synthetic silica because of good ink absorbability.

The average particle diameter of the pigment is preferably 0.5 to 2.0 μm. If the average particle size is less than 0.5 μm, the ink absorption rate is lowered and printing blurring occurs. In the present invention, since the coating amount of the ink receiving layer is 1.0 g / m ² or less for the purpose of leaving the texture of the substrate, if the average particle diameter exceeds 2.0 μm, the pigment is removed from the coated ink receiving layer. (For example, silica particles) protrude, the surface of the ink receiving layer becomes rough, and the texture of the substrate cannot be reproduced.

  The use ratio of the pigment is not limited, but is about 50 to 85% by mass of the solid content of the receiving layer. If it is less than 50%, the ink absorbability is insufficient, and if it exceeds 85%, the strength of the ink receiving layer may be lowered.

  Examples of the surfactant in the ink receiving layer include nonionic surfactants, cationic surfactants, anionic surfactants, and amphoteric surfactants, but the use of nonionic surfactants is preferred. Specifically, polyoxyethylene alkyl ether, oxyethyleneoxypropylene block copolymer, sugar alcohol fatty acid ester, polyoxyethylene sugar alcohol fatty acid ester, fatty acid monoglyceride, polyoxyethylene alkylamine, monoalkyltrimethylammonium chloride, dialkyldimethylammonium chloride And benzalkonium chloride or a mixture thereof, and those having an HLB value of 10.0 to 15.0 are used. If the HLB value is less than 10.0, a sufficient ink absorption speed cannot be obtained. If the HLB value exceeds 15.0, the ink is absorbed in the Z-axis direction of the ink jet recording paper and at the same time, the ink is also absorbed in the XY direction. Spreading, resulting in blurring. By using these surfactants, good ink absorption performance can be obtained with a small coating amount.

  The use ratio of the surfactant is about 10 to 30% by mass of the solid content of the receiving layer. If it is less than 10%, the ink absorption performance is insufficient, and if it exceeds 30%, there is a concern that the strength of the ink receiving layer may be reduced.

  Examples of the binder in the ink receiving layer include polyvinyl alcohol and cationic polyvinyl alcohol, polyvinyl alcohol derivatives such as silyl-modified polyvinyl alcohol, proteins such as polyvinyl pyrrolidone and casein, starch and derivatives thereof, styrene-butadiene copolymer, and methyl methacrylate. -Conjugated diene polymer latex such as butadiene copolymer, acrylic polymer latex such as acrylate ester and methacrylate ester polymer or copolymer, ethylene-vinyl acetate copolymer, ethylene-vinyl chloride copolymer Vinyl polymer latex such as these, or functional group-containing modified polymer latex such as carboxyl groups and cationic groups of these polymers, synthetic resin-based aqueous adhesives such as melamine resin and urea resin, maleic anhydride polymerization Polymers such as oil-based, polyacrylamide-based, polymethylmethacrylate-based, polyurethane-resin-based, unsaturated polyester-resin-based, polyvinylbutyral-based, alkyd-resin-based synthetic resin adhesives can adhere to pigments or substrates In addition, since the liquid-absorbing property is improved because it has good affinity with water-based ink, it is preferably used.

  The ratio of the adhesive used in the ink receiving layer is not limited, but is about 10 to 45% by weight, preferably 10 to 40% by weight, of the solid content of the receiving layer. If it is less than 10%, the adhesive strength is insufficient, and there is a concern that the strength of the receiving layer is lowered. On the other hand, if it exceeds 45%, the adhesive strength increases, but the use ratio of the pigment decreases, and there may be a problem in the ink absorbency as described above.

  Also, for the purpose of improving the water resistance of printed images with water-based ink, polydiallyldimethylammonium resin, polyethyleneimine resin, polyamine resin, polyamide resin, polyamide epichlorohydrin resin, polyamine epichlorohydrin resin, polyamide polyamine epichlorohydrin A cationic polymer compound such as a resin, a polydiallylamine resin, or a dicyandiamide condensate can be suitably used.

  If necessary, pigment dispersants, thickeners, antifoaming agents, antifoaming agents, foaming agents, mold release agents, penetrating agents, wetting agents, thermal gelling agents, lubricants, and other various types known in the art. Auxiliaries can be used.

  The water-absorbing support in the ink jet recording medium of the present invention may be a support having a function of absorbing the ink solvent, for example, silica, talc, kaolin, calcined kaolin, carbonic acid as required for papermaking pulp. Examples thereof include papers prepared by a method commonly used in acidic or neutral papermaking by adding a filler such as calcium, and dry or wet nonwoven fabrics. In the case of paper, the ash value according to JIS-P8128 is preferably less than 8%, and more preferably less than 5%. When the ash value increases, the ink absorption performance tends to slightly decrease although there is no practical problem.

  As means for coating the ink-receiving layer on these water-absorbing supports, size press, gate roll, roll coater, bar coater, gravure coater, air knife coater, rod blade coater, blade coater, die coater, or It can be appropriately selected from commonly used coating means such as curtain coaters.

The coating amount of the ink receiving layer is 0.2 to 1.0 g / m ² . If it is less than 0.2 g / m ² , sufficient ink absorption performance cannot be obtained, and if it exceeds 1.0 g / m ² , the texture of the support cannot be reproduced because the ink receiving layer covers the support.

  The water-based ink used for the ink jet recording medium of the present invention contains at least one of a water-soluble direct dye and a water-soluble acid dye as a dye, and in addition, a wetting agent, a dye dissolving agent, and a preservative. Contains antifungal agents and the like. Examples of water-soluble direct dyes include CI. Direct black, CI. Direct yellow, CI. Direct Blue, CI. Direct red and the like, and water-soluble acid dyes include CI. Acid Black, CI. Acid Yellow, CI. Acid Blue, CI. Acid red and the like can be mentioned, but are not necessarily limited to these.

  Hereinafter, the present invention will be described more specifically by way of examples. However, the present invention is not limited to these examples. In addition, the number of parts and% in an Example mean a mass part and mass%.

Example 1
“Creation of coated base paper for inkjet paper (Creation of water-absorbing support)”
90 parts of LBKP with a freeness of 450 mlcsf is mixed with 10 parts of NBKP with a freeness of 480 mlcsf, 4 parts of calcium carbonate, 0.1 part of alkyl ketene dimer, 0.05 part of cationic poly (meth) acrylamide, 1 part of cationized starch Then, 0.5 parts of a sulfuric acid band was added, a base paper having a basis weight of 110 g / m ² was made with a long net paper machine, and a 2% starch solution was applied to a coating amount of 0.4 g / m ² after drying on one side. As described above, coating and drying were performed using a size press apparatus, and a coated base paper for inkjet paper having an ash content value of 3.8% according to JIS-P8128 was obtained.

"Creation of ink jet recording medium (formation of ink receiving layer)"
55 parts of an amorphous silica pigment [trade name: Cylicia 310; manufactured by Fuji Silysia Co., Ltd., particle size 1.4 μm] is dispersed in 600 parts of water, and polyvinyl alcohol as a binder (trade name: Kuraray Poval). PVA-117, manufactured by Kuraray Co., Ltd.] 10 parts of 10% aqueous solution, cationic resin [trade name: Unisense CP103, manufactured by Senka Co., Ltd.] 10 parts, polyoxyalkylene alkyl ether as a surfactant [trade name: Neugen ET -143 Daiichi Kogyo Seiyaku Co., Ltd., HLB value 12.1] 15 parts was added to obtain an ink-receiving layer coating solution. The coating liquid is applied and dried on the above-mentioned base paper for inkjet paper using a Mayer bar so that the coating amount after drying is 0.5 g / m ² , and then super calendering is performed to prepare an inkjet recording medium. Obtained.

Example 2
“Preparation of base paper for inkjet paper (preparation of water-absorbent support)”
In the same manner as in Example 1, a coated base paper for inkjet paper was obtained.
"Creation of ink jet recording medium (formation of ink receiving layer)"
Polyoxyethylene lauryl ether [trade name: Neugen ET-143 Daiichi Kogyo Seiyaku Co., Ltd., HLB value 12.1] 15 parts of polyoxyethylene lauryl ether [trade name: Neugen ET-102 Daiichi Kogyo Seiyaku ( Co., Ltd., an HLB value of 10.8] was used in the same manner as in Example 1 except that 15 parts were used to obtain an inkjet recording medium.

Example 3
“Preparation of base paper for inkjet paper (preparation of water-absorbent support)”
In the same manner as in Example 1, a coated base paper for inkjet paper was obtained.
"Creation of ink jet recording medium (formation of ink receiving layer)"
Polyoxyethylene lauryl ether [trade name: Neugen ET-143 Daiichi Kogyo Seiyaku Co., Ltd., HLB value 12.1] 15 parts polyoxyethylene alkyl ether [trade name: Neugen ET-165 Daiichi Kogyo Seiyaku ( Co., Ltd., HLB value 14.5] An ink jet recording medium was obtained in the same manner as in Example 1 except that 15 parts were used.

Comparative Example 1
“Preparation of base paper for inkjet paper (preparation of water-absorbent support)”
In the same manner as in Example 1, a coated base paper for inkjet paper was obtained.
"Creation of ink jet recording medium (formation of ink receiving layer)"
Polyoxyethylene lauryl ether [trade name: Neugen ET-143 Daiichi Kogyo Seiyaku Co., Ltd., HLB value 12.1] 15 parts of polyoxyethylene lauryl ether [trade name: Neugen ET-83 Daiichi Kogyo Seiyaku ( Co., Ltd., HLB value 6.4] An ink jet recording medium was obtained in the same manner as in Example 1 except that 15 parts were used.

Comparative Example 2
“Creation of coated base paper for inkjet paper (Creation of water-absorbing support)”
In the same manner as in Example 1, a coated base paper for inkjet paper was obtained.
"Creation of ink jet recording medium (formation of ink receiving layer)"
Polyoxyethylene lauryl ether [trade name: Neugen ET-143 Daiichi Kogyo Seiyaku Co., Ltd., HLB value 12.1] 15 parts of polyoxyethylene lauryl ether [trade name: Neugen ET-190 Daiichi Kogyo Seiyaku ( Co., Ltd., HLB value 16.5] An ink jet recording medium was obtained in the same manner as in Example 1 except that 15 parts were used.

Comparative Example 3
“Creation of coated base paper for inkjet paper (Creation of water-absorbing support)”
In the same manner as in Example 1, a coated base paper for inkjet paper was obtained.
"Creation of ink jet recording medium (formation of ink receiving layer)"
5 parts of polyoxyethylene lauryl ether [trade name: Neugen ET-143 Daiichi Kogyo Seiyaku Co., Ltd., HLB value 12.1] is used, and an amorphous silica pigment [trade name: Silicia 310; manufactured by Fuji Silysia Ltd., Particle size 1.4 μm] An ink jet recording medium was obtained in the same manner as in Example 1 except that 75 parts were used.

“Creation of coated base paper for inkjet paper (Creation of water-absorbing support)”
In the same manner as in Example 1, a coated base paper for inkjet paper was obtained.
"Creation of ink jet recording medium (formation of ink receiving layer)"
Polyoxyethylene lauryl ether [trade name: Neugen ET-143 Daiichi Kogyo Seiyaku Co., Ltd., HLB value 12.1] 35 parts of amorphous silica pigment [trade name: Silicia 310; manufactured by Fuji Silysia Ltd., Particle diameter 1.4 μm] An ink jet recording medium was obtained in the same manner as in Example 1 except that 45 parts were used.

Example 4
“Creating base paper for inkjet paper (base material creation)”
In the same manner as in Example 1, a coated base paper for inkjet paper was obtained.
"Creation of ink jet recording medium (formation of ink receiving layer)"
75 parts of amorphous silica pigment [trade name: Cylicia 310; manufactured by Fuji Silysia Co., Ltd., particle size 1.4 μm] was converted to amorphous silica pigment [trade name: Silojet 710C; manufactured by Grace Devison Co., Ltd., particle size 1. An ink jet recording medium was obtained in the same manner as in Example 1 except that it was changed to [0 μm].

Example 5
“Creating base paper for inkjet paper (base material creation)”
In the same manner as in Example 1, a coated base paper for inkjet paper was obtained.
"Creation of ink jet recording medium (formation of ink receiving layer)"
Amorphous silica pigment [trade name: Sirisia 310; manufactured by Fuji Silysia Co., Ltd., particle size 1.4 μm] to amorphous silica pigment [trade name: Siricia 350; manufactured by Fuji Silysia Co., Ltd., particle size 1.8 μm] An ink jet recording medium was obtained in the same manner as Example 1 except for the change.

Comparative Example 5
“Creating base paper for inkjet paper (base material creation)”
In the same manner as in Example 1, a coated base paper for inkjet paper was obtained.
"Creation of ink jet recording medium (formation of ink receiving layer)"
Amorphous silica pigment [trade name: Cylysia 310; manufactured by Fuji Silysia Co., Ltd., particle size 1.4 μm] was converted to an amorphous silica pigment [trade name: Silojet 703C; Grace Devison Co., Ltd., particle size 0.3 μm]. An ink jet recording medium was obtained in the same manner as in Example 1 except that the above was changed.

Comparative Example 6
“Creating base paper for inkjet paper (base material creation)”
In the same manner as in Example 1, a coated base paper for inkjet paper was obtained.
"Creation of ink jet recording medium (formation of ink receiving layer)"
Amorphous silica pigment [trade name: Sirisia 310; manufactured by Fuji Silysia Co., Ltd., particle diameter of 1.4 μm] is converted to amorphous silica pigment [trade name: Siricia 440; manufactured by Fuji Silysia Co., Ltd., particle diameter of 3.5 μm]. An ink jet recording medium was obtained in the same manner as Example 1 except for the change.

Example 6
“Creating base paper for inkjet paper (base material creation)”
90 parts of LBKP with a freeness of 450 mlcsf is mixed with 10 parts of NBKP with a freeness of 480 mlcsf, 10 parts of calcium carbonate, 0.1 part of alkyl ketene dimer, 0.05 part of cationic poly (meth) acrylamide, 1 part of cationized starch Then, 0.5 part of a sulfuric acid band is prepared, a base paper having a basis weight of 110 g / m ² is made with a long paper machine, and a 2% starch solution is applied after drying on one side to a coating amount of 0.4 g / m ² . As described above, coating and drying were performed using a size press apparatus, and a coated base paper for inkjet paper having an ash content value of 9.0% according to JIS-P8128 was obtained.

Comparative Example 7
“Creating base paper for inkjet paper (base material creation)”
In the same manner as in Example 1, a coated base paper for inkjet paper was obtained.
"Creation of ink jet recording medium (formation of ink receiving layer)"
An inkjet recording medium was obtained in the same manner as in Example 1 except that the coating amount was 0.1 g / m ² .

Comparative Example 8
“Creating base paper for inkjet paper (base material creation)”
In the same manner as in Example 1, a coated base paper for inkjet paper was obtained.
"Creation of ink jet recording medium (formation of ink receiving layer)"
An ink jet recording medium was obtained in the same manner as in Example 1 except that the coating amount was 1.3 g / m ² .

  Table 1 shows the results of evaluating the print density, print definition, print fixability, and print water resistance of the obtained ink jet recording medium.

"Evaluation"
1. Evaluation Printing A commercially available color inkjet printer, Hewlett-Packard Company's Design Jet 1055CM, was used to print black, cyan, magenta, yellow single colors and red, green, blue heavy solid and thin images.

2. Using a printed image density Macbeth reflection densitometer RD914, the reflection density of a black, cyan, magenta, and yellow single-color solid image printed with a Hewlett Packard Design Jet 1055CM was measured.

3. Sensitive evaluation was performed on the blur of 200% heavy color printed portions of 100% cyan and 100% magenta that were independently printed on a white paper portion with a contour jet Hewlett-Packard Design Jet 1055CM.
Evaluation criteria A: Excellent.
○: Good.
Δ: Slightly inferior
X: Inferior.

4). Border Jijimi Hewlett-Packard Design Jet 1055CM prints so that the 100% cyan and 100% magenta 200% overprinting part and the 100% cyan and 100% yellow printing part come into contact with each other. evaluated.
Evaluation criteria A: Excellent.
○: Good.
Δ: Slightly inferior
X: Inferior.

5). Reproducibility of base material The prepared inkjet recording paper was compared with the base material and judged visually.
Evaluation criteria A: Excellent.
○: Good.
Δ: Slightly inferior
X: Inferior.
Xx: Very inferior.

The present invention is an inkjet recording medium that does not impair the texture of the substrate, has excellent image reproducibility, and good print fixability. It is possible to provide recording papers having various textures such as recording paper using paper as a support.

Claims (3)

In an inkjet recording medium having an ink-receiving layer on a water-absorbing support, the ink-receiving layer has a porous pigment having an average particle diameter of 0.5 to 2.0 μm, a binder, and an HLB value of 10.0 or more and 15 0.0 or less of the surfactant, and the surfactant is contained in an amount of 10 to 30% by mass of the ink receiving layer, and the dry coating amount of the ink receiving layer is in the range of 0.2 to 1.0 g / m ² . An ink jet recording medium provided with the above.   2. The ink jet recording medium according to claim 1, wherein the water-absorbing support is paper having an ash value of less than 5% according to JIS-P8128. The ink jet recording medium according to claim 1 or 2, wherein the ink receiving layer contains 50 to 85% by mass of a porous pigment of 0.5 to 2.0 µm.