JP2694771B2 - Recording medium and recording method using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a recording material suitably used in an ink jet recording method, and in particular, it is excellent in absorptivity and color development of a water-based ink and is excellent in sharpness of a recorded image obtained. An excellent recording material.

Further, the present invention relates to a recording material that provides a recorded image excellent in storability with less discoloration of the image indoors and the like, and an inkjet recording method that provides the recorded image.

(Prior Art) Conventionally, as a recording material for ink jet, (1) a general paper containing pulp as a main component, which is made into a low size degree, such as a filter paper or a blotter paper, ( 2) As disclosed in JP-A-56-148585, there is known a base paper having a low ink absorbability such as general high-quality paper, provided with an ink absorbing layer using a porous inorganic pigment. .

On the other hand, particularly in the ink jet recording method that requires formation of a high-quality and high-resolution color image, the following is required for the recording material used.

(1) good color developability of the ink adhered to the recording material, (2) good circularity of the ink dots, (3) even if a plurality of ink drops adhere to the same spot,
Good ink absorption capacity that the adhered ink does not flow out, (4) Good ink fixability that the adhered ink droplet does not bleed even if it is rubbed immediately afterwards, (5) Water resistance and light resistance of the formed image Good image storability.

However, a recording material satisfying all the above required performances has not yet been known.

(Problems to be Solved by the Invention) Particularly recently, the problem of indoor discoloration of recorded images has been highlighted as a problem peculiar to coated paper.

The problem of light resistance, which has been a problem in the past, is the problem of browning of images due to irradiation with sunlight, for example, ultraviolet light or visible light, and it can be applied to so-called general PPC paper and fine paper to coated paper for inkjet. Although it is a problem that occurs even in images printed on paper, the problem of indoor discoloration in the present invention occurs, for example, in images stored in a place not exposed to direct sunlight, and non-coating such as PPC paper. This is a separate issue from lightfastness, which does not occur in images printed on paper.

For example, the method described in JP-A-60-49990 is a method for improving the light resistance, and is not effective for indoor discoloration. As described above, the problem of indoor discoloration is a problem peculiar to coated paper, and it is presumed that the problem is caused by the pigment forming the coat layer.

That is, for example, the coated paper using silica having a strong activity as disclosed in JP-A-56-185690 provides an image with high optical density, but has a serious problem of indoor discoloration. Conversely, low specific surface area calcium carbonate, kaolin,
When a general filler for paper such as talc or silica is used, indoor discoloration is suppressed, but this time, there is a problem that the image density is reduced.

Thus, in particular, the problems of indoor discoloration and image density are contradictory problems, which are problems that cannot be solved by the conventional techniques.

Therefore, an object of the present invention is to provide a recording material which has a high density of a recorded image, is excellent in ink absorbability and color development of a dye, and can obtain a high-quality and high-resolution image.

Another object of the present invention is to provide a recording material which gives a recorded image with little storability of the recorded image, particularly less deterioration due to indoor discoloration, and an inkjet recording method for forming such an image.

(Means for Solving Problems) The above and other objects of the present invention are achieved by the following present invention.

That is, the present invention, the BET specific surface area is a recording material characterized by having a surface layer mainly composed of aluminum oxide particles in the range of 60 to 170 m ² / g and a lower layer having ink absorbability, and an aqueous ink. In the ink jet recording method in which the droplets are applied to a recording material, the water-based ink contains an acid dye and / or a direct dye, and the recording material is
The inkjet recording method is a recording material having a surface layer mainly composed of aluminum oxide particles having a BET specific surface area of 60 to 170 m ² / g and a lower layer having ink absorbability.

(Operation) The present inventors did not cause discoloration in the room on the non-coated paper,
Since it is a phenomenon that occurs only on coated paper, as a result of studying the relationship between the pigment that forms the ink receiving layer, the coat layer, and the room color change, it was identified as a pigment that forms the ink receiving layer, especially the recording surface that captures the dye. The present inventors have found that the problem of indoor discoloration is unlikely to occur when the above pigment is used, and thus the present invention has been accomplished.

(Preferred Embodiment) Next, the present invention will be described in more detail with reference to preferred embodiments.

The first feature of the recording material of the present invention is that the surface layer, which is the recording surface, is formed mainly of aluminum oxide particles having a BET specific surface area in the range of 60 to 170 m ² / g.

The aluminum oxide particles referred to in the present invention are usually called the Bayer method, and are produced by baking aluminum hydroxide obtained by treating natural mineral bauxite with hot caustic soda. In addition to this, metal aluminum pellets are also used. After spark discharge in water, a method of firing the obtained aluminum hydroxide, vaporizing aluminum chloride at high temperature,
Those produced by a method of oxidizing in a gas phase, a method of decomposing an inorganic aluminum salt (such as alum), or the like can also be used.

As the crystal structure of aluminum oxide particles, it is known that the aluminum oxide of kibsite type or boehmite type is transformed into γ, σ, η, θ, α type aluminum oxide depending on the temperature of heat treatment. Of course, any of these manufacturing methods and crystal structures can be used in the present invention.

The purity of the aluminum oxide particles varies depending on the production method and the degree of purification, but those usable in the present invention are not limited to those containing 99.99% aluminum oxide (Al ₂ O ₃ ) usually called high purity alumina, Al ₂ O ₃ 80 to 90%
It is sufficient to include the above.

The preferred BET specific surface area of the aluminum oxide particles used in the present invention is in the range of 90 to 170 m ² / g.
If the BET specific surface area of the aluminum oxide particles exceeds 170 m ² / g, the indoor discoloration of the recorded image becomes remarkable, which is not preferable.

According to the knowledge of the present inventor, the indoor discoloration of the recorded image is due to the oxidative decomposition of the dye, and when the dye is trapped on the surface layer of the recording material, the dye is more likely to be contacted with air and oxidized. In particular, when the pigment was captured by a pigment having a large specific surface area, the area of contact with the ventilation was maximized and the indoor discoloration was severe.

Therefore, in the present invention, it is desirable to use a pigment having a specific surface area of 170 m ² / g or less.

On the other hand, when pigments such as silica and calcium carbonate, which have been conventionally used for inkjet paper, and have a specific surface area of 170 m ² / g or less are used for the ink receiving layer, the adsorption of the pigment to the dye Due to the lack of strength, the dye in the attached ink penetrates deeply into the paper layer together with the solvent in the ink, and although the problem of indoor discoloration was solved, the color developability and image density of the dye were insufficient. .

This is the first reason why pigments having a BET specific surface area of 170 m ² / g or less have not heretofore been used for coated paper as described above.

However, according to the knowledge of the present inventor, even with a BET specific surface area of 170 m ² / g or less, for example, when aluminum oxide particles are used, a sufficient effect of suppressing indoor discoloration of an image can be obtained, and Excellent image density can be obtained.

Among various inorganic pigments as described above, only the aluminum oxide particles, while having a specific surface area of 170 m ² / g or less, it is unknown why it is possible to provide an image with excellent optical density, According to the inventor's imagination, the aluminum oxide particles have a surface having a positive charge and are likely to electrically adsorb an acidic dye and / or a direct dye,
The paper using such aluminum oxide particles can capture more dye near the surface of the ink receiving layer, that is, in the surface layer, and because the dye and the aluminum oxide particles are electrically bonded. , The dye near the surface is stabilized,
The reason why it is difficult to decompose is considered.

Further, when aluminum oxide particles having a BET specific surface area of less than 60 m ² / g are used, the density of the formed image becomes insufficient, so that one having a BET specific surface area of 60 m ² / g or more is used.

According to the knowledge of the present inventor, when silica is used as a pigment forming the recording surface (surface layer), the specific surface area of silica and the image density, and the strong correlation between the specific surface area and indoor discoloration,
Prevention of indoor discoloration and improvement of image density are not compatible, and it is difficult to improve both at the same time.

In this way, the two properties tend to contradict each other in the same manner as in the case of aluminum oxide particles, but in the case of using aluminum oxide particles, the tendency for the image density to increase relative to the specific surface area of the pigment is greater than that of silica. Remarkable and the desired image density is low compared to silica (170 m ² / g
The following particles have the advantages that can be achieved, which is the reason why the present invention can improve both the indoor discoloration preventing property and the image density improvement.

The average particle size of the aluminum oxide particles used in the present invention is preferably 5 μm or less, more preferably 3 μm or less, and further preferably 1 μm or less.

That is, by using the aluminum oxide particles having the specific surface area as described above, the image density and the indoor storability are improved by several steps as compared with the conventional inkjet paper, but the image density and the indoor storability are still traded. Have an off relationship.

That is, according to the knowledge of the present inventor, in order to have more excellent indoor storability while maintaining a high image density, the above-mentioned aluminum oxide particles having an average particle diameter of 5 μm or less should be used. Is preferable, and more preferably 3
μm or less, more preferably 1 μm or less.

Those having an average particle size of more than 5 μm are insufficient for suppressing indoor discoloration. The average particle size here is the particle size when the ink receiving layer is formed. Generally, the primary particle diameter of aluminum oxide particles is 1 nm to 1
Since it is about μm, it is preferable in the present invention that the particles do not form secondary particles. Further, from the viewpoint of ink absorbability, the average primary particle diameter of the aluminum oxide particles is preferably 0.5 μm or less. 0.5 μm
Those having a viscosity of more than 10% have insufficient ink absorbency.

Further, according to the knowledge of the present inventor, the correlation between the particle size of aluminum oxide particles and the image density is low, but the smaller the particle size, the better the indoor storability.

This is because when a recording surface is formed, it is larger when a pigment having a larger particle diameter is used than when particles having a small apparent surface area on the recording surface are stacked, and the dye adsorbed is easily oxidized. It seems that it is because it has become.

In the conventional recording material, secondary particles are formed from the viewpoint of improving ink absorbency, and a pigment having a large particle diameter has been used. In the present invention, there is no problem in ink absorbability even if the surface layer is formed by sub-micron-order particles that do not form secondary particles because the ink receiving layer has a special structure described later. by.

A second feature of the present invention is that the recording material of the present invention is composed of a surface layer containing the above-mentioned aluminum oxide particles and an ink absorbing lower layer.

The surface layer referred to in the present invention is a layer constituting the recording surface, which itself cannot absorb and hold the entire amount of the attached ink, but mainly adsorbs the dye in the received ink,
Most of the ink solvent has the function of migrating to the lower layer of the ink-absorbing material as it passes.

Therefore, the recording material of the present invention has a recording surface in which the pigment forming the surface layer and the fibrous substance of the base paper are mixed and / or the recording surface has a maximum thickness of 20 μm, more preferably 15 μm or less. It has a form covered with a surface layer.

The preferable coating amount of the surface layer in the present invention is in the range of 0.3 to 7 g / m ² as the total amount of pigment. Coating amount is 0.3g / m
If it is less than ² , it is ineffective compared to the case where the surface layer is not provided. On the other hand, if it is provided over 7 g / m ² or if the maximum thickness of the surface layer exceeds 20 μm, Similar to the case of the recording material (2), particularly when the above-mentioned aluminum oxide particles are used, problems such as a marked decrease in ink absorbency, a decrease in indoor discoloration prevention property, and generation of paper dust occur.

In the present invention, the more preferable coating amount of the pigment on the surface layer is in the range of 1 to 7 g / m ² , and more preferably 2 to 7 g / m ² .

The maximum thickness of the surface layer in the present invention is the maximum value of the thickness of the surface layer in the depth direction in the cross section of the recording material, and the pigment coating amount is the amount of the pigment coated as the surface layer. The coating amount of the pigment of the surface layer is obtained by the method of JIS-P-8128 and can be obtained as a value obtained by subtracting the ash content of the base paper from the ash content of the entire recording material.

In the present invention, the surface layer is formed mainly of the above-mentioned aluminum oxide particles, and, for example, conventionally known materials such as silica, aluminum silicate, magnesium silicate, calcium silicate, calcium carbonate, clay, kaolin, talc and diatomaceous earth. Inducing pigments such as inorganic pigments and urea resins in
You may mix and use it in the range which does not exceed 20 weight%.

As the pigment forming the surface layer as described above, it is desirable to contain 80% by weight or more of aluminum oxide particles,
When the content of aluminum oxide particles is less than 80% by weight, the image density decreases, and depending on the type of pigment used in combination, the problem of room storability cannot be solved, which is not preferable.

As described above, in the recording material of the present invention, by providing a relatively small amount of the surface layer, the recording material that can satisfy each required performance is obtained, because the ink absorbing lower layer as shown below By using in combination.

As described above, in the aspect of the present invention, the particle size is, for example, on a polyethylene terephthalate film as in Example 2 of JP-A-58-110287.
A pulp fiber was internally filled with alumina particles such as those in the prior art in which an amount of 15 g / m ² of an ink receiving layer was provided by using 30 μm alumina particles and those disclosed in JP-A-58-110288. It is separate from the example given above.

Specific examples of preferable recording materials having an ink-absorbent lower layer in the present invention include (1) a mode in which a surface layer is provided on a liquid-absorbent base paper, and the base paper also serves as the ink-absorbent lower layer; Examples include a mode in which a pigment layer having excellent ink absorbency is provided on paper and a surface layer is provided thereon.

 Each aspect will be specifically described below.

The aspect (1) is the most preferable aspect of the present invention in view of problems such as indoor discoloration, paper dust, etc., manufacturing stability, and cost.

The surface layer of this embodiment is composed of a pigment containing the aluminum oxide particles and a binder, and examples of the binder used in the present invention include conventionally known polyvinyl alcohol, starch, oxidized starch, cationized starch, casein, and carboxy. One or more of water-soluble polymers such as methyl cellulose, gelatin, hydroxyethyl cellulose and acrylic resins and water-dispersible polymers such as SBR latex and polyvinyl acetate emulsion can be mixed and used.

In this embodiment, the suitable use ratio (weight ratio) of all pigments and binders is 1/4 to 10/1, more preferably 1/2 to
The ratio is 4/1, and when the amount of the binder is larger than 1/4, the ink absorbency of the coat layer is lowered, and on the other hand, from 20/1, the powder of the pigment is greatly removed from the coat layer, which is not preferable.

The base paper on which the above-mentioned surface layer is provided needs to be ink-absorbent, and its preferable Steckigt sizing degree (JIS-
The range of P-8122) is 0 to 15 seconds, more preferably 0 to 15 seconds.
It is 10 seconds, more preferably 0 to 8 seconds. When a base paper having a Steckigt size of more than 15 seconds is used, the ink absorbency of the entire recording material is insufficient, which is not preferable.

It is desirable that the recording medium having the above-mentioned coating layer on the base paper has a Steckigt sizing degree in the range of 0 to 15 seconds.
When it exceeds the second, most of the ink absorption depends on the coat layer in the above range, and the ink absorption becomes insufficient.

In the present invention, the pulp constituting the base paper is not particularly limited, mainly wood pulp represented by conventionally known LBKP and NBKP, but may be mixed with synthetic fibers or glass fibers if necessary. .

Specific examples of the base paper filler used in the present invention include commonly used clay, talc, kaolinite, titanium oxide, calcium carbonate and the like, and particularly in the present invention,
To 1 These filler in terms of ash content 20 g / m ^2, more preferably contained in a range of 2 to 10 g / m ^2.

According to the knowledge of the present inventors, in particular, the bleeding and dot shape of ink droplets adhering to the recording material are greatly affected by the ash content of the base paper in this type of paper, and the ash content is less than 1 g / m ² . If there is no ink droplet, the adhered ink droplet largely bleeds along the fiber direction on the surface of the base paper, the dot shape is bad and the ink droplet bleeding becomes larger than necessary. On the other hand, when the amount exceeds 20 g / m ² , on the other hand, the recording material itself loses its elasticity, and in addition, powder is dropped from the base paper, which is not preferable.

Further, among the above-mentioned fillers, calcium carbonate is preferable because the dot shape and color developability are particularly good.

The ash content of the base paper in the aspect of the above (1) is determined by dissolving the ink receiving layer from the recording material by using a good solvent for the binder, and separating the ash content of the obtained base paper according to JIS-
It is obtained by the method of P-8128, and it is obtained as the mass of ash per unit area of paper at that time. For example, in general inkjet paper, polyvinyl alcohol is used as a binder. In this case, after the recording material is immersed in static hot water and the coating layer is removed, the ash content as the base paper is removed. The amount can be calculated.

The base paper used in the aspect of the above (1) is produced by using the above-mentioned materials and conventionally known paper making aids, sizing agents, yield improving agents, paper strength enhancers and the like as necessary.

The preferable basis weight range of the base paper used in the embodiment (1) is 60 to 120 g / m ² . That is, since the recording material of the aspect (1) absorbs ink by the base paper, when the basis weight of the base paper is less than 60 g / m ² , high density printing causes strikethrough and cockling. And so on. On the other hand, if it exceeds 120 g / m ² , the stiffness of the paper becomes too strong, which causes a problem in transportability in the recording apparatus.

Since the recording material of the aspect (2) absorbs ink only by the pigment layer, it is excellent in ink absorbency and dot shape, and is suitable for providing a high-resolution and high-quality image.

The feature of the recording material of the aspect (2) is that the ink receiving layer is 2
This is that it has a layer structure of at least one layer and includes an ink holding layer formed mainly of a pigment having a larger average particle size than the above-mentioned aluminum oxide particles.

The ink holding layer is preferably formed mainly of a pigment having a (average) particle diameter of 5 to 30 μm, more preferably a silicon-containing pigment, more preferably synthetic silica, and the aluminum oxide particles constituting the recording surface described above. Is disposed below the layer including.

In the above aspect (2), a pigment having a large particle size is used as the ink holding layer, and fine irregularities on the surface thereof are filled with a pigment having a small particle size in the layer constituting the recording surface to use the large pigment. By taking advantage of the case, it is possible to obtain an image having a better dot shape and no graininess without causing powder falling.

The specific surface area of the pigment forming the ink holding layer is preferably not less than that of the pigment mainly composed of the surface layer, more preferably not less than 200 m ² / g from the viewpoint of ink absorbability. In terms of color developability and ink absorbency, it is preferable that the ink absorbency of the surface layer is slow enough that the droplets adhering to the surface bleed to an appropriate size, and the ink absorbability of the ink holding layer is large. For this purpose, the use ratio of the pigment and the binder in the surface layer constituting the recording surface is 1/3 to 5/1, more preferably
1/2 to 3/1, total ink receiving layer is 1/1 to 10 /
A range of 1 is preferred. Further, any of the above-mentioned conventionally known binders can be used for forming the ink holding layer. The total coating amount of the ink receiving layer is preferably 2 to 50 g / m ² ,
More preferably, the coating amount of the ink holding layer is larger than that of the surface layer within the range of 8 to 30 g / m ² .

Further, in order to improve the ink absorbability of the recording material of the aspect (2), it is preferable to use a spherical pigment as disclosed in JP-A-62-183382 as a pigment for forming the ink holding layer. Porous silica particles having a particle shape can be used. In particular, when the spherical silica having an average particle diameter of 5 to 30 μm is used for the ink holding layer, it is possible to form an ink receiving layer having a higher void volume than that using a conventional amorphous pigment. It is possible to provide a recording material having excellent ink absorbency.

In preparing the recording material of the present invention in each of the above aspects, a coating solution containing the components as described above is prepared by a known method,
For example, the base material surface is coated by a roll coater method, a blade coater method, an air knife coater method, a gate roll coater method, a size press method or the like. Further, after the aqueous coating liquid comprising the pigment and the binder is applied on the substrate, it is dried using a conventionally known drying method, for example, a hot air drying oven, a heating drum or the like to obtain the recording material of the present invention. .

Further, in order to smooth the surface of the ink receiving layer or increase the surface strength of the ink receiving layer, a super calendar may be used in the process.

Further, in the present invention, a dye fixing material (waterproofing agent), a fluorescent whitening agent, a surfactant, a defoaming agent, a pH adjusting agent, an antifungal agent, an ultraviolet absorbing agent, an antioxidant is optionally added to the ink receiving layer. Etc. may be contained.

Using the ink jet recording method for the recording material of the present invention having the above-described structure, recording is performed with a multicolored water-based ink such as yellow (Y), magenta (M), cyan (C), black (Bk), etc. According to the recording method of the present invention, a color change does not occur in the obtained image in the room, and a recorded image excellent in storability can be obtained.

The method of the present invention is an inkjet recording method using the recording material of the present invention. In this recording method, the ink itself applied to the specific recording material as described above by the inkjet recording method may be a known one. The recording agent is a water-soluble dye represented by a direct dye, an acid dye, a basic dye, a reactive dye, an edible pigment, and the like, which is particularly suitable as an ink for an inkjet recording system, and is combined with the above-described recording material. The preferred ones that give images satisfying the required performances such as fixing property, color forming property, sharpness, stability, light resistance and the like are, for example, CI Direct Black 17, 19, 32, 51, 71, 108, 14
6, CI Direct Blue 6, 22, 25, 71, 86, 90, 106, 1
99, CI Direct Red 1, 4, 17, 28, 83, CI Direct Yellow 12, 24, 26, 86, 98, 142, CI Direct Orange 34, 39, 44, 46, 60, CI Direct Violet 47, 48, Direct dyes such as CI Direct Brown 109 and CI Direct Green 59, CI Acid Black 2, 7, 24, 26, 31, 52, 63, 11
2, 118, CI Acid Blue 9, 22, 40, 59, 93, 102, 104, 11
3, 117, 120, 167, 229, 234, CI Acid Red 1, 6, 32, 37, 51, 52, 80, 85,
Acid dyes such as 87, 92, 94, 115, 180, 256, 317, 315, CI Acid Yellow 11, 17, 23, 25, 29, 42, 61, 71, CI Acid Orange 7, 19 and CI Acid Violet 49 , CI Basic Black 2, CI Basic Blue 1, 3, 5, 7, 9, 24, 25, 2
6, 28, 29, CI Basic Red 1, 2, 9, 12, 13, 14, 37, CI Basic Violet 7, 14, 27 and CI Food Black 1, 2 can also be used.

The above dye examples are particularly preferable for the ink applicable to the inkjet recording method of the present invention, and the dye for the ink used in the present invention is not limited to these dyes.

Such a water-soluble dye is generally used at a ratio of about 0.1 to 20% by weight in a conventional ink, and the same may be used in the present invention.

The solvent used in the water-based ink used in the present invention is water or a mixed solvent of water and a water-soluble organic solvent, and particularly preferable are water and a mixed solvent of a water-soluble organic solvent, and as a water-soluble organic solvent. It contains a polyhydric alcohol having an ink drying prevention effect. As the water, it is preferable to use deionized water instead of general water containing various ions.

The content of the water-soluble organic solvent in the ink is generally 0 to 95% by weight, preferably 2 to 95% by weight based on the total weight of the ink.
It is 80% by weight, more preferably 5 to 50% by weight.

The preferred water content is 20 to total ink weight.
It is 98%, more preferably 50 to 95%.

In addition, the ink used in the present invention may include a surfactant, a viscosity modifier, a surface tension modifier, and the like, if necessary, in addition to the above components.

In the method of the present invention, a method for applying the above-mentioned ink to the recording material to perform recording is an ink jet recording method, and the method is a range-forming member that effectively separates ink from a nozzle. Any method may be used as long as it can apply ink to the recording material.

In particular, according to the method described in JP-A-54-59936, the ink subjected to the action of thermal energy causes a sudden change in volume, and the ink is ejected from the nozzle by the action force due to this state change. Can be used effectively.

(Effect) The recording material of the present invention as described above is particularly suitable as a recording material for inkjet recording using an aqueous ink, and has the following effects.

(1) Since the water-based ink has high absorbency, after applying the ink,
Immediately after drying, the same state is obtained, and even if a part of the recording device or fingers adhere to them, they are not contaminated or the recorded image is not stained.

(2) When used for inkjet recording, in addition to the effect of (1) above, the dots are close to a perfect circle and have a high density, and the dots do not excessively bleed and feathering does not occur, resulting in clear and high resolution. High-quality images can be formed.

(3) It is suitable for color printers because it has excellent color characteristics.

(4) The problem of image storability peculiar to coated paper is small, and in the ink jet recording method using the recording material and the multicolor ink of the present invention, the obtained image is stored in an office for one to several months without direct sunlight. The problem of indoor discoloration that occurred when stored in a wall or drawer does not occur.

(Examples) Next, the present invention will be described in more detail with reference to Examples and Comparative Examples. In the description, parts and% are based on weight unless otherwise specified.

Examples 1 to 4 As a substrate, a Steckigt sizing degree of 5 seconds, a basis weight of 66 g / m ² , JI
Using the one containing 9.0% (5.9g / m ² ) of calcium carbonate in terms of ash content according to S-P-8128, the coating liquid of the following composition should be 5g / m ² in dry coating amount. Was coated by a bar coater method and dried at 110 ° C. for 3 minutes to obtain a recording material of the present invention.

Composition of coating liquid Pigment 24 parts Polyvinyl alcohol (PVA-117, Kuraray) 8 parts Polyvinyl alcohol (PVA-105, Kuraray) 4 parts Water 200 parts The pigments used are shown in Table 1 below.

Comparative Example 1 PP with Steckigt sizing degree of 24 seconds and basis weight of 66 g / m ² as base paper
A recording material for comparison was prepared in the same manner as in Example 1 except that C paper (Canon NP dry paper) was used as the base paper.

Examples 5 to 8 and Comparative Examples 2 and 3 Base paper having a Steckigt sizing degree of 0 seconds, a basis weight of 65 g / m ² , and a calcium carbonate content of 2.4% (1.6 g / m ² ) in terms of ash content. A coating solution having the same composition as in Example 1 was applied by a bar coater method so that the dry coating amount would be 7 g / m ^2.
The recording material of the present invention and the comparative recording material were obtained by drying at 3 ° C for 3 minutes.

As the pigment, as shown in Table 2, alumina and other pigments were mixed and used.

The inkjet recording suitability of the above recording material is 1 in 1 mm.
Using an inkjet printer having four nozzles of Y, M, C, and Bk, each having an inkjet head having 128 nozzles at an interval of 6 nozzles, inkjet recording was performed using an ink having the following composition for evaluation.

Ink composition Dye 5 parts Diethylene glycol 20 parts Water 78 parts Dye Y: CI Direct Yellow 86 M: CI Acid Red 35 C: CI Direct Blue 199 Bk: CI Food Black 2 The following items were evaluated. The result is the third below.
It is shown in the table.

(1) Ink absorbency was evaluated using the above inkjet printer. Each of the print boundaries printed with the colors Y, M, C, and Bk had no color mixture and was clear.

(2) Image Density Using the same inkjet printer as above, the image density of a solid printed matter (BK) was evaluated using a Macbeth reflection densitometer RD-918.

(3) The indoor storage property is the printed matter (BK) used in (2) above.
Was stuck on the wall of the office and left for 6 months. Difference between the chromaticity of the image immediately after printing (before leaving) and the chromaticity of the image after leaving Δ
E ^* ab was calculated and used as the evaluation of indoor storability.

(4) Regarding paper dust, when the surface of the ink receiving layer was scratched with a pencil having a hardness of H, the coat layer was peeled off or scraped to cause a large amount of paper dust.
And

Examples 9 to 11 and Comparative Examples 4 and 5 A general high-quality paper (silver ring trade name, manufactured by Sanyo Kokusaku Pulp Co., Ltd.) was used as a base material, and a dry coating amount was 20 using the following coating liquid I.
It is coated by a bar coater method so as to be g / m ² and dried at 110 ° C. for 5 minutes to form an ink holding layer. On the ink holding layer, the following coating liquid II is used for dry coating. The amount of 7 g / m ² was applied by a bar coater method and dried at 110 ° C. for 3 minutes to form a surface layer to obtain a recording material of the present invention and a recording material for comparison.

Composition of coating liquid I Synthetic silica (spherical silica, BET specific surface area 700 m ² / g, average particle size 20 μm, made by Asahi Glass) 18 parts Polyvinyl alcohol (RVA-117 / R-1130, made by Kuraray) 6 parts Water 76 parts Coating Liquid II composition (Example 9) Porous alumina (RG-40, manufactured by Iwatani Chemical Co., BET specific surface area 48 m ² / g) 13 parts Polyvinyl alcohol (PVA-110, manufactured by Kuraray) 10 parts Water 77 parts (Example 10) ) Fine particle alumina (Aerosil Aluminum Oxide-C, manufactured by Nippon Aerosil, BET specific surface area 100 m ² / g) 13 parts Polyvinyl alcohol (PVA-110, manufactured by Kuraray) 10 parts Water 77 parts (Example 11) High-purity alumina (AKP) -G, manufactured by Sumitomo Chemical, BET specific surface area 130 m ² / g) 13 parts Polyvinyl alcohol (PVA-110, manufactured by Kuraray) 10 parts Water 77 parts (Comparative Example 4) Fine silica (Cyloid 74, manufactured by Fuji Devison, BET) Specific surface area 300 m ² / g) 13 parts Polyvinyl alcohol ( PVA-110, Kuraray) 10 parts Water 77 parts (Comparative Example 5) Zinc oxide (activated zinc flower AZO, manufactured by Shodo Kagaku, BET specific surface area 64 m ² / g) 13 parts Polyvinyl alcohol (PVA-110, manufactured by Kuraray) ) 10 parts water 77 parts Example 12 The following coating liquid III was applied to the same base paper as in Example 9 by the bar coater method so that the dry coating amount was 20 g / m ^2, and 110 An ink holding layer is formed by drying at 5 ° C. for 5 minutes, and the ink holding layer is coated with the following coating liquid IV by a bar coater method so that the dry coating amount is 7 g / m ² . 110
A surface layer was formed by drying at 3 ° C. for 3 minutes to obtain a recording material of the present invention.

Composition of coating liquid III Synthetic silica (Cyroid 620, BET specific surface area 300 m ² / g, average particle size 12 μm, made by Fuji Davison) 20 parts Polyvinyl alcohol (PVA-117, made by Kuraray) 5 parts Water 75 parts Coating liquid IV composition γ-alumina (Hijilite UA-5605, Showa Denko, BET specific surface area 64 m ² / g) 12 parts Polyvinyl alcohol (PVA-110, Kuraray) 11 parts Water 77 parts Comparative Example 6 On the base paper used in Example 10. Was coated by the bar coater method so that the coating amount was 15 g / m ² using the following coating liquid.
It was dried at 0 ° C. for 5 minutes to form a lower layer having low ink absorbability. On the lower layer, the coating liquid II used in Example 10 was applied and dried in the same manner as in Example 10, and the recording material 6 for comparison was used for comparison.
I got

Composition of coating solution Polyvinylpyrrolidone (PVP K-90, manufactured by GAF) 9 parts Isobutylene / maleic anhydride copolymer (isoban 10; manufactured by Kuraray Isoprene Chemical) 3 parts Dimethylformamide 88 parts Examples 9 to 12 above and comparison The evaluation of each recording material of Examples 4 to 6 was performed on the following items. The results are shown in Table 4 below.

(1) The ink absorbency was evaluated using the inkjet printer described above. In the mixed color portion of the two color inks of the recorded image, the line thicker than the single color portion, the one in which the outflow of the ink occurs was marked with X, the one without the line thickening was marked with O, and the one with a slight line thickening was marked with Δ. Furthermore, ◎ means that the line thickness does not occur even in the overlapping portion of the three colors.

(2) As for the room storability, a solid pattern of Bk was printed using the above printer, stuck on the wall of the office, and left for 6 months. The difference (ΔE ^* ab) between the chromaticity of this image and the chromaticity of the image immediately after printing was determined, and the indoor discoloration was evaluated.

(3) Colorability was measured by using a high-speed color analyzer CA-35 (manufactured by Murakami Color Science Co., Ltd.) to measure the saturation of the printed matter (Y, M, C) solidly printed using the above printer.

(4) The image density was measured by using the Macbeth densitometer RD-914 to measure the OD of the printed matter (Bk) solidly printed using the above printer.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Emi Munakata 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (56) References JP-A-60-260376 (JP, A) JP-A-62 -169680 (JP, A) JP-A-62-174182 (JP, A)

Claims (19)

(57) [Claims] 1. A recording material having a surface layer mainly composed of aluminum oxide particles having a BET specific surface area of 60 to 170 m ² / g and a lower layer having ink absorbability. 2. A BET specific surface area of aluminum oxide particles is 9
The recording material according to claim 1, which is in a range of 0 to 170 m ² / g. 3. The average particle diameter of aluminum oxide particles is 5.
The recording material according to claim 1, having a thickness of not more than μm. 4. The average particle diameter of aluminum oxide particles is 1.
The recording material according to claim 1, having a thickness of not more than μm. 5. Aluminum oxide particles are used for all pigments on the surface layer.
The recording material according to claim 1, which accounts for 80% by weight or more. 6. The recording material according to claim 5, wherein the coating amount of the pigment on the surface layer is in the range of 0.3 to 7 g / m ² . 7. The recording material according to claim 1, wherein the Steckigt sizing degree according to JIS-P-8122 is in the range of 0 to 15 seconds. 8. The recording material according to claim 1, wherein the lower layer is a base paper having a Steckigt sizing degree according to JIS-P-8122 in the range of 0 to 15 seconds. 9. The base paper contains 1 to 20 g / m ^{2 of} filler in terms of ash content.
The recording material according to claim 8, wherein the recording material is contained in the range of. 10. The recording material according to claim 9, wherein the filler is calcium carbonate. 11. The recording material according to claim 8, wherein the basis weight of the base paper is in the range of 60 to 120 g / m ² . 12. The recording material according to claim 1, wherein the lower layer is a layer mainly containing a pigment. 13. The recording material according to claim 12, wherein the average particle size of the pigment is larger than the average particle size of the aluminum oxide particles in the surface layer. 14. The recording material according to claim 13, wherein the average particle diameter of the pigment is in the range of 5 to 30 μm. 15. The recording material according to claim 12, wherein the pigment is synthetic silica. 16. The recording material according to claim 12, wherein the BET specific surface area of the pigment is 200 m ² / g or more. 17. The recording material according to claim 1, which is for inkjet recording. 18. An ink jet recording method comprising applying a small droplet of an aqueous ink to a recording material, wherein the aqueous ink contains an acid dye and / or a direct dye, and the recording material has a BET specific surface area of 60. To 170 m ² / g, the inkjet recording method is characterized by being a recording material having a surface layer mainly composed of aluminum oxide particles and a lower layer having ink absorbability. 19. The ink jet recording method according to claim 18, wherein heat energy is applied to the ink to apply the ink.