JPH08104057A - Recording material - Google Patents

Abstract

(57) Abstract: [PROBLEMS] To provide a full-color recording material for inkjet recording which satisfies various requirements for inkjet recording, particularly has high ink absorbability and excellent color developability. SOLUTION: An ink receiving layer mainly composed of inorganic pigment particles fixed by a binder mainly composed of a water-soluble polymer and having a Bekk smoothness of the surface of 20 seconds or more and 120 seconds or less is formed on a support. The recording material for inkjet recording is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording material (recording paper) used in an inkjet recording method, and more particularly to a recording material having high ink absorbability and excellent ink color development.

[0002]

2. Description of the Related Art A method of recording using a recording liquid has been common since ancient times such as writing with a fountain pen, but recently, a so-called ink jet recording system has also appeared, and the recording liquid is used here. ing.

The ink jet recording method generates droplets of a recording liquid according to various operating principles and causes the droplets to fly and adhere to a recording material such as paper for recording. However, noise is less generated. , Has attracted attention as a recording method capable of high-speed printing and multicolor printing. As a recording liquid for inkjet recording, an aqueous liquid is mainly used from the viewpoint of safety and printability.

As a recording material used in this ink jet recording method, conventional ordinary paper has been generally used. However, with the improvement of the performance of the inkjet recording device such as high-speed recording or multi-color recording, more advanced characteristics are required for the recording material for inkjet recording. That is, as a recording material for ink jet recording for obtaining a high resolution and high quality recording image, 1) ink absorption should be as quick as possible, 2) ink dots should be adhered later when they overlap. Ink does not flow to the previous dot, 3) the diameter of the ink dot does not become larger than necessary, 4) the shape of the ink dot is close to a perfect circle, and its periphery is smooth, 5) ink It is necessary that the density of the dots is high and that the surroundings of the dots are not blurred and that the required performance such as is satisfied.

Further, in order to obtain a recording image quality comparable to that of a color photograph by the multi-color ink jet recording system, in addition to the above required performance, 6) high whiteness, 7) coloring property of ink coloring component 8) It is excellent, and 8) Ink droplets of the same number as the number of colors of the ink may adhere to the same place in piles, so that the ink absorption is particularly excellent. Required.

[0006]

However, the actual situation is that no recording material satisfying all of these required performances has been found yet. For example, in the ink jet recording paper described in JP-A-52-74304, the ink is absorbed quickly, but the dot diameter is apt to be large, the periphery of the dot is easily blurred, and the dimensional change of the paper after recording. Has the drawback of being large.

An object of the present invention is to provide a full-color recording material for ink jet recording which satisfies the above-mentioned requirements and has particularly high ink absorbency and excellent color developability.

[0008]

The recording material for ink jet recording of the present invention is a recording material for ink jet recording having a support provided with an ink receiving layer, wherein the ink receiving layer is water-soluble on the support. Inorganic pigment particles having a particle size of 3 to 20 μm fixed by a binder mainly composed of a polymer are mainly used, and the Beck smoothness of the ink receiving layer is in the range of 20 seconds to 120 seconds. Characterize.

The recording material of the present invention is characterized by a unique surface state exhibited by the ink receiving layer as a layer for receiving ink during recording. That is, the Beck smoothness of the ink receiving layer is in the range of 20 seconds or more and 120 seconds or less, and more specifically, this means that, for example, an irregular shape having a relatively large particle diameter which is the main component of the ink receiving layer. The inorganic pigment particles of No. 1 have a structure appearing on the surface of the coating layer in a state where they are randomly placed, and a structure in which a large number of large voids functioning as ink absorption holes are scattered between these particles It means to take, and is typically shown as a surface state in FIG. Of course, the inorganic pigment particles appearing on these surfaces are also fixed in the ink receiving layer by the binder and are not easily detached from the ink receiving layer. FIG. 1 shows about 150 of the ink receiving layer surface of the recording material of the present invention.
It is an enlarged view obtained from a 0X scanning electron microscope photograph, and shows well the surface condition of the ink receiving layer, which is represented by a specific smoothness, which should be expressed as if rubble of various sizes is scattered.

On the other hand, FIG. 2 is an enlarged view obtained from an electron micrograph of the same magnification of the surface of a recording material having a conventional ink receiving layer. The surface of this recording material has a large number of fine pores serving as ink absorption holes, and has a flat surface structure of the ink receiving layer. The value of Beck smoothness is large, and the recording material of the present invention is It is clearly distinguished from wood.

As described above, since the surface of the ink receiving layer of the recording material of the present invention has a large and large number of voids between the inorganic pigment particles which become the ink absorbing holes, the ink is not recorded when the ink is recorded. Is rapidly absorbed in the gaps between the inorganic pigment particles, and the ink absorption capacity is large.

When the Beck's smoothness value of the ink receiving layer is less than 20 seconds, the ink absorbency is insufficient, while when the Beck's smoothness value exceeds 120 seconds, the ink absorbency is good. However, the resolution of the recorded image decreases.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION As the support for the recording material of the present invention, it is suitable to use paper, but cloth, resin film or synthetic paper can also be used.

The ink receiving layer of the recording material of the present invention is mainly composed of inorganic pigment particles fixed on a support with a binder. The inorganic pigment particles include, for example, silica, clay, talc, diatomaceous earth, calcium carbonate, calcium sulfate, barium sulfate, titanium oxide, zinc oxide, satin white, aluminum silicate, lithopone, alumina, white amorphous such as zeolite. One or more types of particles composed of an inorganic pigment can be used.

In order for the irregular shape of the inorganic pigment particles to appear as scattered rubble on the surface of the ink receiving layer, and for the ink receiving layer to have a specific Beck's smoothness, the particle size is 3 to 20 μm.
Inorganic pigment particles of about m are used. If the particle size of the inorganic pigment particles is too large, the roundness of the ink dots will be impaired and the resolution of the recorded image will decrease, which is not preferable.

The inorganic pigment particles are preferably as high as possible in dye absorption, and more preferably have a porous structure. This is because the coloring property is better when the dye in the ink absorbed in the gaps between the inorganic pigment particles is captured on the outermost surface of the ink receiving layer of the recording material.

The binder for fixing the inorganic pigment particles on the support is mainly composed of a water-soluble polymer, and the water-soluble polymer includes starch, gelatin, casein,
One or more water-soluble polymers such as gum arabic, sodium alginate, carboxymethyl cellulose, polyvinyl alcohol, polyvinylpyrrolidone, sodium polyacrylate and polyacrylamide can be used. If necessary, a binder component other than the water-soluble polymer may be used in combination with the water-soluble polymer. Examples of such other binder component include, for example, synthetic resin latex such as synthetic rubber latex, polyvinyl butyral, polyvinyl chloride, polyvinyl acetate, polyacrylonitrile,
Examples thereof include organic solvent-soluble resins such as polymethyl methacrylate, polyvinyl formal, melamine resin, polyamide resin, phenol resin, polyurethane resin and alkyd resin, and one or more of these can be used in combination with a water-soluble polymer. .

The ink receiving layer contains a dispersant, a fluorescent dye, and p.
Various additives such as an H adjuster, an antifoaming agent, a lubricant, a preservative, and a surfactant can also be mixed.

For the recording material of the present invention, a coating liquid prepared by dispersing these components for forming the ink receiving layer in a medium such as water is used for roll coating, rod bar coating and spray coating. It can be produced by coating on a support by an air knife coating method or the like and then drying as quickly as possible.

The mixing ratio of the inorganic pigment particles and the binder in the coating liquid is preferably 10 to 100 parts by weight of the binder with respect to 100 parts by weight of the inorganic pigment particles. When the diameter is large, it is advantageous to use as little binder as possible.

The amount of the coating layer on the support is a dry coating amount, and can be usually about 1 to 50 g / m ² . The upper limit of the dry coating amount is preferably about 30 g / m ² . The lower limit is preferably about 2 g / m ² and 10 g
/ M ² is more preferable.

In this way, the recording material of the present invention in which the ink receiving layer having a specific Beck's smoothness is provided on the support has extremely high ink absorbency, and recording liquids of different colors are the same within a short time. Even if they are adhered to the portions in duplicate, the recording liquid does not flow out or bleed out, and a high-resolution clear image is provided. Moreover, it exhibits excellent properties in color development, and is suitable as a recording material for inkjet recording when full-color recording is performed.

[0023]

The present invention will be described in more detail below with reference to examples. Example 1 Silica as an inorganic pigment particle (Cyloid 404, trade name, manufactured by Fuji Devison Chemical Co., Ltd., average particle diameter: 10 μm)
m) and calcium carbonate (average particle diameter: 2 μm), polyvinyl alcohol and SBR latex were used as a binder to prepare an ink-receiving layer coating composition based on the following composition.

Silica 100 parts by weight Calcium carbonate 15 parts by weight Polyvinyl alcohol 30 parts by weight SBR latex 3 parts by weight Water 500 parts by weight On the other hand, as a support, a standard fine paper having a size degree of 35 seconds according to JIS P8122 (basis weight 65 g / M ² ), and the above coating composition is coated on the support at a dry coating amount of 1
Coating at a rate of 0 g / m ^{2 by} a blade coater method,
A recording material was obtained by drying by a conventional method. The surface of the ink receiving layer of this recording material as shown in a scanning electron microscope photograph at a magnification of about 1500 was as shown in FIG. The Beck's smoothness value of this recording material was 108 seconds. Beck's smoothness is measured by the Oken air permeability smoothness tester (Asahi Seiko Co., Ltd.).
Manufactured).

Example 2 Inorganic pigment particles were diatomaceous earth (Celite 281, trade name, manufactured by John Manville, average particle size: 8 μm), starch and SBR latex were used as binders, and an ink was prepared based on the following composition. A composition for coating the receiving layer was prepared.

Diatomaceous earth 100 parts by weight Starch 30 parts by weight SBR latex 10 parts by weight Water 800 parts by weight On the other hand, the same general fine paper as in Example 1 was used as a support, and the above coating composition was applied on this support. Dry coating amount 1
Coating at a rate of 0 g / m ^{2 by} a blade coater method,
A recording material was obtained by drying by a conventional method. The Beck's smoothness value of this recording material was 28 seconds.

Example 3 Zeolite (average particle size: 10 μm) as inorganic pigment particles
m) and talc (average particle diameter: 7 μm), and using casein as a binder, an ink-receiving layer coating composition was prepared based on the following composition.

Zeolite 100 parts by weight Talc 10 parts by weight Casein 20 parts by weight Water 500 parts by weight On the other hand, the same general fine paper as in Example 1 was used as a support, and the above coating composition was applied on this support. Dry coating amount 1
Coating at a rate of 5 g / m ^{2 by} a blade coater method,
A recording material was obtained by drying by a conventional method. The Beck's smoothness value of this recording material was 60 seconds.

Comparative Example 1 Commercially available art-coated paper (trade name: SK) as a recording material
The surface of the ink receiving layer shown in a scanning electron microscope photograph of about 1500 times that of Coat manufactured by Sanyo Kokusaku Pulp Co., Ltd. was as shown in FIG. The Bekk smoothness of the surface of the ink receiving layer of the recording material was 1200 seconds.

Comparative Example 2 Calcium carbonate (average particle size: 50) as inorganic pigment particles
μm) and polyvinyl alcohol as a binder to prepare a coating composition based on the following composition.

Calcium carbonate 100 parts by weight Polyvinyl alcohol 20 parts by weight Water 500 parts by weight On the other hand, the same general high-quality paper as in Example 1 was used as a support, and the above coating composition was dry-coated on this support. Effort 1
Coating at a rate of 5 g / m ^{2 by} a blade coater method,
A recording material was obtained by drying by a conventional method. The value of Beck's smoothness of this recording material was 10 seconds.

Reference Example Color ink jet recording was performed on these five types of recording materials using the four color inks shown in Table 1 below, and the recording characteristics were evaluated based on the criteria described below. The results are shown in Table 2. The colors shown in parentheses in the evaluation column of each recording property in Table 2 are the colors of the inks used in the evaluation.

[0033]

[Table 1] Evaluation Criteria for Recording Characteristics: (1) The dot density was measured using a Sakura Microdensimeter PDM-5 (manufactured by Konishi Rokusha Kogyo KK) for printed dots. (2) Regarding the dot shape, when the printed dots were observed with a stereoscopic microscope, the circle was almost circular, the circle was slightly distorted, and the irregular shape was x. (3) The degree of bleeding was measured by measuring the diameter of the printed dot with a stereoscopic microscope and indicated by the multiple of the ink droplet. (4) With regard to color vividness, the color vividness of ink jet recorded images was visually compared, and the best one was marked with ⊚ and the worst one was marked with x, and ranked as ⊚, ◯, Δ, and x. (5) The ink absorbency is cyan, magenta, yellow,
When four black inks were overprinted and recorded, the ink did not flow out and the image was clear.

[0034]

[Table 2]

[0035]

The recording material of the present invention comprises a support and a coating layer mainly composed of inorganic pigment particles and having a unique surface condition. Even if the ink is repeatedly attached to the same place within a short time, there is no outflow or bleeding phenomenon of the ink, it is possible to give a high-resolution clear image, and it also exhibits excellent characteristics in color development. It is suitable as a recording material for inkjet recording when full-color recording is performed.

[Brief description of drawings]

FIG. 1 is an enlarged view of about 1500 times the surface of a coating layer of a recording material of the present invention.

FIG. 2: About 150 of the surface of the coating layer of commercial art-coated paper
It is an enlarged view of 0 times.

Claims (9)

[Claims] 1. A recording material for inkjet recording, comprising a support having an ink receiving layer, wherein the ink receiving layer comprises:
Inorganic pigment particles having a particle size of 3 to 20 μm, which are fixed on the support by a binder mainly composed of a water-soluble polymer, are mainly composed, and the Beck smoothness of the ink receiving layer is 20.
A recording material for inkjet recording, which is in the range of 1 second or more and 120 seconds or less. 2. The recording material for ink jet recording according to claim 1, wherein the inorganic pigment particles are white amorphous inorganic pigment particles. 3. The inorganic pigment particles are silica, clay, talc, diatomaceous earth, calcium carbonate, calcium sulfate, barium sulfate, titanium oxide, zinc oxide, satin white,
The recording material for inkjet recording according to claim 1, which is selected from aluminum silicate, lithopone, alumina, and zeolite. 4. The recording material for ink jet recording according to claim 1, wherein the inorganic pigment particles are selected from silica, calcium carbonate, diatomaceous earth, zeolite and talc. 5. The water-soluble polymer is starch, gelatin,
The recording material for inkjet recording according to claim 1, which is selected from casein, gum arabic, sodium alginate, carboxymethyl cellulose, polyvinyl alcohol, polyvinylpyrrolidone, sodium polyacrylate, and polyacrylamide. 6. The recording material for inkjet recording according to claim 1, wherein the water-soluble polymer is selected from polyvinyl alcohol, starch, and casein. 7. The recording material for ink jet recording according to claim 1, wherein the inorganic pigment particles are silica and the water-soluble polymer is polyvinyl alcohol. 8. The amount of the ink receiving layer is 2 g as a dry coating amount.
/ M ² or more and 30 g / m ² or less, the recording material for inkjet recording according to claim 1. 9. The amount of the ink receiving layer is 10 in dry coating amount.
The recording material for inkjet recording according to claim 8, which has a g / m ² or more.