JP2002347329A - INK JET RECORDING MEDIUM AND ITS MANUFACTURING METHOD - Google Patents

Abstract

(57) [Summary] [Problem] To be excellent in ink absorption speed of ink jet, to have a small color difference (ΔE) over time after recording an image or character by ink jet, and to print (offset or gravure printing). The present invention provides an ink jet recording medium which is suitable for ink jet recording in which the texture and the feeling of an image are visually similar to a printed matter, and can be a substitute for proof printing, and a method for manufacturing the same. At least two layers of a porous ink absorbing layer mainly composed of hydrotalcites and a porous ink dyeing layer mainly composed of alumina are laminated on one surface of a support in this order. Preferably, the recording medium for ink-jet recording is a crystalline alumina, for example, an alumina recording medium prepared by a dry method.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording medium for recording information such as images and characters by an ink-jet printer and a method for manufacturing the same. The present invention relates to an ink jet recording medium which is excellent in glossiness, good in appearance, good in coloring of a recording portion, and good in color gamut stability, and particularly suitable for use in, for example, offset printing and gravure printing.

[0002]

2. Description of the Related Art In recent years, various types of printers for computer output have become widespread. Above all, an ink jet printer is excellent in quietness, cost, and image quality, can reproduce a full-color image with high quality, has excellent performance not found in other systems, and can be expected to spread further. Especially in recent years,
With the control of ink droplets, the development of light and shade inks, and the improvement of the performance of the dye image receiving layer, the technology has advanced until an image equivalent to a silver halide photograph can be obtained. In particular, in recent years, ink jet printers are often used for proof printing of offset printing or gravure printing. Therefore, development of an ink jet receiving paper dedicated to proof printing has been desired.

[0003] The characteristics required of the ink-jet calibration paper are that the printing paper (real paper) must have a texture that is similar in appearance and a color density and a color gamut that can support offset printing and gravure printing. It is. The most important thing here is the change in color gamut.Even if the color gamut is changed after several hours or several days even if color matching is performed after printing with an inkjet printer, Not practical.

In an ink jet recording system, it is common to use an aqueous ink as the ink and a recording paper having a dye receiving layer formed on a support as a recording paper. Here, to give a general technical example of a recording medium,
By providing as a recording medium a cation component added to a receiving layer in which porous silica is dispersed in polyvinyl alcohol, the ink is absorbed into the silica pores by a physical action, and the cation component is added. A method of chemically fixing the dye, or a method of chemically fixing the dye with alumina while physically absorbing the ink using an alumina sol, or physically absorbing the ink by swelling using a cationic resin. There is a method in which the dye is chemically fixed by the cation portion while performing the above.

However, all of the methods have advantages and disadvantages, and none of them satisfy the characteristics required for the above-mentioned ink jet calibration paper. For example, JP-A-9-
According to Japanese Patent No. 5806, there is proposed an ink jet recording medium in which an organic acid acts on an interlayer compound to fix and hold a dye by an intercalation reaction. When we reproduced this, the ink fixability was recognized and the color difference (ΔE) value was relatively small. However, since the interlayer compound has a hiding property, an image has an impression of white spots, and is not similar to an offset printed matter or a gravure printed matter.

Further, in order to take advantage of the respective advantages, there is a case where each layer has a layered structure having characteristics. For example, JP-A-5-160094 proposes a recording sheet having a porous silica layer on a base material and a porous layer containing alumina or alumina hydrate on the porous layer. However, in the recording medium obtained by this method, the dye in the ink discharged from the ink jet is fixed only by the action of alumina or alumina hydrate in the upper layer. In particular, when this layer was reproduced and examined using dry alumina, when this layer was made thinner, the dye penetrated to the lower silica layer, and eventually, bleeding occurred during long-term storage. The color difference (Δ
The value of E) was also large. On the other hand, when the upper layer is thickened,
Cracks, haze increases,
It was not practical because of the problem of higher costs.

[0007]

That is, with the prior art, it has not been possible to obtain an ink jet recording medium suitable for use in proof printing of offset printing or gravure printing. The present invention has been made in view of the above-mentioned problems of the conventional technology, and particularly has an excellent ink-absorbing speed of an ink jet, and a color difference over time after recording an image or a character by the ink jet ( ΔE) is excellent in characteristics such as a small value, and further, compared with printed matter by normal printing (offset printing, gravure printing, etc.)
Provided are an ink jet recording medium capable of obtaining performance suitable for ink jet recording in which the texture and the feeling of an image are visually similar, and a method for manufacturing the same.

[0008]

Means for Solving the Problems The present invention has been made to solve the above problems, and the present inventors have made intensive studies and, as a result, have solved the problems. According to the present invention, it is possible to obtain an ink jet recording medium which is very suitable for use in providing an output of an ink jet printer as a substitute for a proof print in normal printing (such as offset or gravure printing).

That is, the means provided by the present invention are as follows. First, a porous ink absorbing layer mainly containing hydrotalcites and a porous ink mainly containing alumina are provided on at least one surface of a support. An ink jet recording medium characterized in that at least two dyeing layers are laminated in this order. (Claim 1)

The recording medium for ink jet recording according to claim 1, wherein said alumina is crystalline. (Claim 2)

3. The ink jet recording medium according to claim 1, wherein said alumina is prepared by a dry method. (Claim 3)

Further, the average primary particle diameter of the alumina is 1
The inkjet recording medium according to any one of claims 1 to 3, wherein the recording medium is in a range of 50 nm to 50 nm. (Claim 4)

The ink jet recording medium according to any one of claims 1 to 3, wherein the average particle diameter of the hydrotalcites is in the range of 0.5 to 10 µm. (Claim 5)

Further, the content of the alumina in the ink dyeing layer is 100 to 1000% by weight based on the components contained in the ink dyeing layer other than the alumina. An inkjet recording medium according to any one of 1 to 4. (Claim 6)

Further, the content of the hydrotalcites in the ink absorbing layer is 100 to 2 with respect to the components contained in the ink absorbing layer other than the hydrotalcites.
The inkjet recording medium according to any one of claims 1 to 5, wherein the content is 00% by weight. (Claim 7)

8. The method according to claim 1, wherein the amount of the ink dyeing layer and the ink absorbing layer formed is smaller in the ink dyeing layer. This is an inkjet recording medium. (Claim 8)

The amount of the ink-dyed layer formed is ² to 20 g / m ^2.
9. An ink jet recording medium according to any one of claims 1 to 8. (Claim 9)

Further, the amount of the ink absorbing layer is formed is 15 to 30 g / m ^2, is an inkjet recording medium according to any one of claims 1 to 9, wherein. (Claim 10)

Then, at least one surface of the support is coated with a coating liquid whose main component is hydrotalcite, and then coated with a coating liquid whose main component is alumina. , On the support, a porous ink absorption layer containing the hydrotalcites as a main component,
A method for producing an ink jet recording medium, characterized by obtaining an ink jet recording medium in which at least two layers of a porous ink dyeing layer containing alumina as a main component are laminated in this order. (Claim 11)

The method according to claim 11, wherein the alumina is crystalline. (Claim 12).

13. The method according to claim 11, wherein the alumina is formed by a dry method. (Claim 13).

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the ink jet recording medium of the present invention or a method for producing the same will be described in more detail. The ink jet recording medium according to the present invention exhibits excellent performance mainly when used in combination with an ink jet printer. Inkjet recording media is for normal printing (offset printing, gravure printing, etc.)
As compared with the printed matter according to the above, a texture and an image feeling similar to the appearance can be obtained, so that it can be suitably used for, for example, offset printing or gravure printing.

The basic structure is that at least one surface of the support has at least two layers of a porous ink absorbing layer mainly composed of hydrotalcites and a porous ink dyeing layer mainly composed of alumina. Are laminated in this order. (Claim 1) The inkjet recording medium according to claim 1, wherein the alumina is crystalline. (Claim 2) As a good example, the recording medium for inkjet according to any one of claims 1 and 2, wherein the alumina is formed by a dry method. (Claim 3)

According to this, by using alumina having an excellent ink fixing property and color developing property for the upper layer, the anionic dye in the inkjet ink is fixed to the cationic alumina particles, so that the color density is high and the color density is high. Because the area becomes wider, especially the color density of offset printing and gravure printing,
It can satisfy the color gamut range and is practical for proofreading use. Further, since the dye is fixed immediately, the variation of the color difference (ΔE) with the passage of time is relatively small, and is suitable for, for example, a proofreading conventionally used in the ordinary printing.

The lower layer is provided with a porous ink absorbing layer containing hydrotalcites as a main component. Solvents, dyes, and other additives of the ink that cannot be absorbed by the upper ink dyeing layer penetrate into the ink absorbing layer. Hydrotalcites are generally layered compounds having a base layer and an intermediate layer. Here, since the surface of the hydrotalcite particles is charged on the positive side, the dye can be fixed. Therefore, the dye is prevented from moving to the lower layer, and as a result, the reflection density on the surface of the image receiving layer shows a high value. Further, since the ink dye is fixed earlier and firmly, the change in the color difference (ΔE) is minimized.

Incidentally, for example, when a porous layer mainly composed of alumina produced by a dry method is used and the image receiving layer is constituted by only this single layer, the change in the color difference (ΔE) is small. In order to obtain a sufficient amount of ink absorbed, a considerable amount of coating is required, and there are problems such as cracking of the film and haze of the printed portion, which is not practical. Further, when the image receiving layer is composed only of a porous layer made of hydrotalcites, it is difficult to fix a large amount of dye quickly and the change in color difference (ΔE) is large. In addition, haze occurs, and the image has an impression of white spots, which is not practical.

According to a fourth aspect of the present invention, there is provided an ink jet recording medium in which the average primary particle diameter of the alumina used is 1 to 50 nm. If the average primary particle diameter is too large, the glossiness of the image receiving paper surface is reduced, and the printed image is not similar to offset printing or gravure printing. In addition, haze increases. On the other hand, if too small, the alumina particles are densely clogged, the ink absorbing ability is reduced, and the ink absorbing speed is reduced. More preferably, the average primary particle size is 5 to 20 nm.

According to the fifth aspect of the present invention, there is provided an ink jet recording medium wherein the average particle diameter of the hydrotalcites used is 0.5 to 10 μm. If too small is used, the ink absorbing ability is reduced and the ink absorbing speed is reduced. Conversely, if too large, the surface becomes brittle, making it difficult to apply the upper layer. More preferably, the average particle size is 2 to 8 μm.

According to the sixth aspect of the present invention, the alumina content of the ink dyeing layer is 20% less than the content of components other than alumina.
It is a recording medium for inkjet which is 0 to 1000% by weight. If the alumina content is low, the ink absorption capacity is poor, and the ink absorption speed is low. On the other hand, when the alumina content is high, the surface may be re-teared, and in some cases, the surface may be peeled off. More preferably, the alumina content is 400 to 900% by weight.

According to the seventh aspect of the present invention, there is provided an ink jet recording medium in which the content of hydrotalcites in the ink absorbing layer is 100 to 200% by weight based on the content of components other than hydrotalcites. If the amount is too small, the ink absorbing ability becomes poor, causing bleeding or a decrease in the absorbing speed, and the dye fixing ability is also inferior, resulting in a large change in color difference. On the other hand, if the amount is too large, the surface becomes brittle, so that application of the upper layer becomes difficult.

It is generally convenient to form the ink dyeing layer and the ink absorbing layer by coating. According to the invention of claim 8, when the state in which the ink-dyed layer is applied and dried is compared with the state in which the ink-absorbing layer is applied and dried, the ink-dyed layer is smaller than the ink-absorbing layer. It is a recording medium.

According to the ninth aspect of the present invention, the coating amount of the ink dyeing layer (after the coating liquid is dried) is ² to 20 g / m ² , and according to the tenth aspect of the present invention, the coating amount of the ink absorbing layer ( (After drying of the coating liquid) is 15 to 30 g / m ² .

The invention of claims 11 to 13 is a preferred method of manufacturing the ink jet recording medium according to the present invention.

The ink dyeing layer is a layer for fixing the dye, and the solvent, additives and the like of the ink mainly penetrate into the lower ink absorbing layer. Therefore, it is preferable to make the ink dyeing layer as thin as possible. However, if it is too thin, gloss is not exhibited, and the printed matter is completely different from an offset printed matter or a gravure printed matter, and is not preferable for proofreading use. In addition, bleeding occurs at the interface between the layers. In addition, the ink absorbing layer needs to have a sufficient coating amount capable of absorbing the ink. However, if the coating amount is too large, the upper layer becomes difficult to apply because the surface is cracked, which is not preferable.

The alumina produced by a dry method suitably used in the present invention refers to an alumina synthesized by a combustion method (gas phase method) in which ammonium chloride is burned in an atmosphere of hydrogen and oxygen, and θ-alumina Is an alumina having crystallinity mainly composed of

Hydrotalcites are layered compounds having a structure comprising a negatively charged intermediate layer between positively charged basic layers. The basic layer is composed of many divalent or trivalent metal ions, and the intermediate layer is composed of hydroxide ions, fluoride ions, chloride ions, acetate ions and the like. Hydrotalcites are generally anion-exchangeable, and it is considered that if a high molecular weight anion is used in the intermediate layer, the dye will be fixed by intercalation.However, since the particle surface also has a positive charge,
The dye settles slightly.

In the present invention, it is considered that the function of fixing the dye is mainly performed in the upper ink dyeing layer, and the dye fixing property by the intercalation in the lower ink absorbing layer is not required. May have a small molecular weight such as a carbonate ion or a hydroxide ion. The basic layer is preferably made of hydrotalcites made of aluminum, magnesium, and silicon.

Further, for both the ink dyeing layer and the ink absorbing layer, a resin is used as a binder, and additives such as a fixing agent, an antioxidant, an ultraviolet absorber, and a thickener are used as necessary. As the resin used here, for example, an acrylic resin, polyvinyl alcohols, urethane resin, polyester, SBR latex, hydroxycellulose, polyvinylpyrrolidone, or another resin can be used alone, or a mixture of two or more resins can be used.

In each layer, a known filler other than alumina and hydrotalcite may be mixed. For example, silica, magnesium oxide, kaolin, talc, calcium sulfate, titanium dioxide, hydrotalcite, zeolite, magnesium hydroxide, aluminum hydroxide, inorganic fillers such as barium sulfate, further polystyrene, polyacrylic, polyethylene,
Organic fillers such as microcapsules and hollow particles can be used.

Further, in order to obtain an ink jet recording medium particularly similar to the texture of a specific printing paper, a pigment is mixed with the ink intermediate layer to adjust the color. The pigment to be used is not particularly limited, but the kind and amount of the pigment which does not deviate from the original purpose of the intermediate layer are selected. For example, titanium yellow is used as a yellow pigment, red iron oxide is used as a magenta pigment, and cobalt blue is used as a cyan pigment.

As the support described in the present invention, a support of any available material can be used. For example,
For various kinds of paper such as synthetic paper, high quality paper, art paper, coated paper, cast coated paper or paperboard, and resins such as polyethylene terephthalate, polyethylene naphthalate, polyvinyl chloride, polycarbonate, cellophane, or polyethylene Resins that have been used, and those obtained by combining the above-mentioned papers and films by lamination or the like are appropriately used. In particular, the use of printing paper such as coated paper is preferable because the texture of the recording medium is more similar to the texture of the printing paper. The surface of the support may be subjected to a corona discharge treatment or a known easy adhesion treatment such as an anchor layer made of a polyurethane resin or the like for the purpose of improving the adhesion of the ink image receiving layer.

The smoothness of the support is irrelevant, and the hardness is not specified. Further, in order to obtain an ink jet recording medium particularly similar to the texture of a specific printing paper, a pigment is mixed with the intermediate layer to adjust the color. The pigment to be used is not particularly limited, but the kind and amount of the pigment which does not deviate from the original purpose of the intermediate layer are selected. For example, titanium yellow is used as a yellow pigment, red iron oxide is used as a magenta pigment, and cobalt blue is used as a cyan pigment.

In preparing the coating liquid constituting each layer of the ink jet recording medium of the present invention, alumina or hydrotalcites, and further, a resin, a filler and an additive are dispersed and mixed together with a solvent using a disperser or the like. A known method may be used.

In the coating, the material is coated on the surface of the support by a known method, for example, a roll coater method, a flade coater method, an air knife coater method, a gate roll coater method, a size press coater method, or the like. Thereafter, drying is performed using a hot-air drying furnace, a hot drum, or the like to obtain the ink jet recording medium of the present invention. As a method of coating, apply the ink absorbing layer, after drying, apply the ink dyeing layer,
Any method may be used, such as a method of drying to complete a two-layer structure, or a method of applying and drying the ink absorbing layer and the ink dyeing layer simultaneously or almost simultaneously.

Further, in order to further develop high gloss, a surface treatment such as a calendar may be performed.

[0046]

The present invention will be described below more specifically with reference to examples and comparative examples. In the description, “parts” are based on weight and based on solid content unless otherwise specified. Note that the present invention is not necessarily limited to the present embodiment.

<Support> The paper used for the support is a general coated paper for printing.

<Coating liquid> (Coating liquid A) Hydrotalcite compound 1 (analytical value: M
gO = 14%, Al2O3 = 34%, SiO2 = 17
%) 60 parts by weight, polyvinyl alcohol (degree of saponification 87)
~ 89%, degree of polymerization 1700) 10% by weight aqueous solution 400
In addition to the parts by weight, glass beads were added and dispersed. At this time,
The solids ratio of hydrotalcite compound 1 to polyvinyl alcohol is 6: 4.

(Coating liquid B) Polyvinyl alcohol (87-89% saponification, polymerization degree 17) was added to 100 parts by weight of a 40% by weight aqueous dispersion of dry alumina 1 (average primary particle diameter 7 nm).
50) by weight of a 10% by weight aqueous solution of
Thereafter, glass beads were added and dispersed. At this time, the solid content ratio of dry alumina 1 and polyvinyl alcohol is 8: 1.

(Coating liquid C) Silica 1 (average primary particle size: 3.
7 μm) in 100 parts by weight of a 40% by weight aqueous dispersion, polyvinyl alcohol (87-89% saponification degree, 170 degree polymerization degree).
50 parts by weight of a 10% by weight aqueous solution of 0) were added little by little, and then glass beads were added and dispersed. At this time, the solid content ratio of dry alumina 1 and polyvinyl alcohol is 8: 1.

(Preparation of Sample) The above coating liquid was applied on a substrate using a wire bar, and dried at 100 ° C. for 5 minutes to form an ink absorbing layer. Thereafter, water or alcohol is applied to the ink absorbing layer, and the above coating liquid is applied thereon without drying, and dried at 100 ° C. for 5 minutes.
An ink jet recording medium was obtained by forming an ink dyeing layer. In addition, an ink absorption layer, an ink dyeing layer,
The combination of the coating liquid and the coating amount used for each is shown in <Table 1.
>.

(Evaluation of Samples) The obtained ink jet recording medium was subjected to Y, M, C, and C using a Canon ink jet printer (product name: BJ-F870).
The ink absorption speed is high in all of the places where solid patterns of R, G, B, and Bk are printed, the examples, and the comparative examples, and the ink does not adhere to hands even if touched immediately after printing. Was.

30 minutes after printing, L, one day after leaving at room temperature,
The a and b values were measured using a colorimeter (Spectrorino, manufactured by Gretag Macbeth). Also, the glossiness of the unprinted area is measured by a 60 ° gloss meter (IG-320, manufactured by HORIBA).
It measured using. The evaluation criteria are shown below. The evaluation results are shown in Table 1.

[Color gamut] The L, a, and b values one day after printing are calculated as
The values were compared with a and b values. ；: Satisfies the color gamut of offset printing. ×: The color gamut of offset printing is not satisfied. [Color difference] ΔE from L, a, b values 30 minutes and 1 day after printing
Was calculated, and the average value of each color was shown. [Glossiness] A: The value of glossiness was 8 or more. X: The value of the glossiness was less than 8.

[0055]

[Table 1]

[0056]

As described above, according to the present invention, characteristics such as excellent ink-absorbing speed of ink-jet and small value of color difference (ΔE) over time after recording an image or a character by ink-jet are obtained. An ink jet recording medium that is excellent and can obtain a performance suitable for ink jet recording whose texture and image feel are visually similar to printed matter by ordinary printing (offset printing, gravure printing, etc.) And a method for producing the same.

[Brief description of the drawings]

FIG. 1 is an explanatory view using a longitudinal section for the outline of one embodiment relating to an ink jet recording medium of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Ink jet recording medium 2 ... Ink image receiving layer 3 ... Support 4 ... Ink absorption layer 5 ... Ink dyeing layer

Claims (13)

[Claims] 1. At least one surface of a support is provided with at least two layers of a porous ink absorbing layer mainly composed of hydrotalcites and a porous ink dyeing layer mainly composed of alumina in this order. An ink jet recording medium characterized by being laminated. 2. An ink jet recording medium according to claim 1, wherein said alumina is crystalline. 3. An ink jet recording medium according to claim 1, wherein said alumina is prepared by a dry method. 4. An alumina having an average primary particle diameter of 1 to 50.
The inkjet recording medium according to any one of claims 1 to 3, wherein the thickness is in the range of nm. 5. The ink jet recording medium according to claim 1, wherein the average particle diameter of the hydrotalcites is in the range of 0.5 to 10 μm. 6. The ink dyeing layer according to claim 1, wherein the content of said alumina in said ink dyeing layer is from 100 to 1000% by weight based on the components other than said alumina contained in said ink dyeing layer. 6. The recording medium for inkjet according to any one of 1 to 5. 7. The ink absorbing layer, wherein the content of the hydrotalcites is 100 to 200% by weight based on the components other than the hydrotalcites contained in the ink absorbing layer. The inkjet recording medium according to claim 1. 8. The ink-jet recording method according to claim 1, wherein the amount of the ink-dyed layer and the ink-absorbing layer is smaller in the ink-dyed layer. Recording media. 9. The amount of the ink-dyed layer formed is 2 to 9.
The ink jet recording medium according to any one of claims 1 to 8, characterized in that a 20 g / m ^2. 10. The amount of the formed ink absorbing layer is 1
The ink jet recording medium according to any one of claims 1 to 9, characterized in that a 5 to 30 g / m ^2. 11. A step of coating at least one surface of a support with a coating solution whose main component is hydrotalcites.
Thereafter, by passing a coating solution containing alumina as a main component, on the support, a porous ink absorption layer containing the hydrotalcites as a main component, and a porous ink absorbing layer containing the alumina as a main component. A method for producing an ink jet recording medium, comprising: obtaining an ink jet recording medium in which at least two high quality ink dyeing layers are laminated in this order. 12. The method according to claim 11, wherein said alumina is crystalline. 13. The method for manufacturing an ink jet recording medium according to claim 11, wherein said alumina is prepared by a dry method.