JP2003251930A - Sheet for ink jet recording - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet for ink jet recording which is excellent particularly in the water resistance and strength of an ink receiving layer and in the density and water resistance of an image and suitable for the outdoor use, e.g. for a poster or the like, while having the fundamental characteristics of a usual sheet for ink jet recording. <P>SOLUTION: The sheet has the ink receiving layer provided on a base. The ink receiving layer contains silica, a calcium carbonate of an aragonite quality, silanol modified polyvinyl alcohol and a hydrated aluminum oxide, and the silica contains 50 wt.% or more of silica of which the capacities of pores are 0.9-1.5 ml/g and the average particle length 2-5 μm. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording sheet, and more specifically, it has an ink receiving layer on a substrate and is excellent in water resistance and strength of the ink receiving layer and in image density and water resistance. The present invention relates to an inkjet recording sheet suitable for outdoor use such as a poster.

[0002]

2. Description of the Related Art In recent years, due to the widespread use of computers, it has become common to print out materials created by computers using printers and the like. As a printer used at that time,
Examples include dot impact printers, laser printers, thermal printers, inkjet printers, and the like, but inkjet printers are widely used because they have almost no mechanical noise during printout and the running cost associated with printout is low.

In such an ink jet recording system, a recording sheet having an ink receiving layer provided on a base material is used. With the expansion of applications, not only image accuracy but also water resistance is required. ing. Conventionally, as the ink receiving layer, those containing silica, polyvinyl alcohol, aluminum oxide and a water-soluble cationic resin are often used, but the water resistance and strength of the ink receiving layer and the density and water resistance of the image (particularly, , When using the water-based pigment ink) was insufficient, and there was a problem in using it outdoors as a poster or the like.

[0004]

Under such circumstances, the present invention has the basic characteristics of the conventional ink jet recording sheet, and in particular, the water resistance and strength of the ink receiving layer and the density of the image. It is an object of the present invention to provide an inkjet recording sheet having excellent water resistance.

[0005]

As a result of earnest studies to develop an ink jet recording sheet having the above-mentioned excellent properties, the present inventor has found that silica containing silica having a specific pore volume and average particle diameter. It has been found that those provided with an ink receiving layer containing aragonite calcium carbonate, silanol-modified polyvinyl alcohol and hydrated aluminum oxide can meet the purpose. The present invention has been completed based on such findings. That is, the present invention comprises an ink receiving layer provided on a substrate, wherein the ink receiving layer is silica, aragonite calcium carbonate,
It contains silanol-modified polyvinyl alcohol and hydrated aluminum oxide, and the silica contains 50% by weight or more of silica having a pore volume of 0.9 to 1.5 ml / g and an average particle diameter of 2 to 5 μm. It is intended to provide an inkjet recording sheet characterized by being silica.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The ink jet recording sheet of the present invention has an ink receiving layer on at least one surface of a substrate. In the present invention, the base material is not particularly limited as long as it is in the form of a sheet.
Various materials such as plastic films, papers, non-woven fabrics and the like can be used, but plastic films are particularly preferable from the viewpoint of water resistance. As the plastic material, it is possible to select a general thermoplastic resin film such as vinyl chloride, polyethylene terephthalate, polypropylene, polystyrene, or polycarbonate, or an inorganic powder such as calcium carbonate or an organic pigment internally added. It is possible.

Foamed plastic films can also be used. Here, the foamed plastic film refers to a plastic film having cracks or voids formed on the surface or inside of the film, or fine bubbles or cavities, and these bubbles or cavities include those such as calcium carbonate. Formed by stretching a film containing inorganic powder and generating it around the inorganic powder (sometimes called a microvoid film), or foaming a foaming agent in a film containing a foaming agent, etc. The name, the forming method, or the generation form of bubbles or cavities does not matter.
The plastic film referred to here also includes what is called synthetic paper.

The substrate may have a single-layer structure or a multi-layer structure,
As the multilayer structure, for example, a method of laminating layers via an adhesive, a so-called co-extrusion method of extruding a plurality of raw materials from a plurality of extruders to join and form a film, a film directly from an extruder on a film. The so-called extrusion laminating method of laminating by laminating while extruding,
Those formed by any known method can be used.

If desired, one or both surfaces of the base material may be subjected to a surface treatment by an oxidation method or a concavo-convex method for the purpose of improving the adhesion or wettability with the ink receiving layer or the like. . Examples of the oxidation method include corona discharge treatment and hot air treatment, and examples of the concavo-convex method include sandblast method and solvent treatment method. These surface treatment methods are appropriately selected according to the type of the base material, but in general, the corona discharge treatment method is preferably used in terms of effects and operability. Also, an easy adhesion treatment can be applied.

In the present invention, the ink receiving layer provided on at least one surface of the substrate contains silica, aragonite calcium carbonate, silanol-modified polyvinyl alcohol and hydrated aluminum oxide.

The silica contained as a filler in the ink receiving layer has a pore volume of 0.9 to 1.5 ml / g,
A silica containing 50% by weight or more of silica satisfying the two conditions of the average particle diameter of 2 to 5 μm is used. When the content of silica having the pore volume and the average particle diameter is less than 50% by weight, the strength of the ink receiving layer, the water resistance of the image, and the bleeding prevention performance deteriorate. The silica to be contained as a filler is adjusted to 50% by weight of silica satisfying the above two conditions.
As described above, another silica may be mixed. At this time, in the silica having a pore volume of 0.9 to 1.5 ml / g and an average particle diameter of 2 to 5 μm, the pore volume exceeds 1.5 ml / g and 2.2 ml / g or less, and the average particle diameter is Is more than 5 μm, the bleeding preventing performance and the image density are further improved, which is preferable. In that case, the content of silica having a pore volume of 0.9 to 1.5 ml / g and an average particle diameter of 2 to 5 μm is 50 to 90% by weight, and the pore volume is 1.
The content of silica exceeding 5 ml / g and 2.2 ml / g or less and having an average particle size of more than 5 μm may be 10 to 40% by weight, and the particle size distribution of silica is in the range of 2 to 5 μm and 5 μm.
It has two peaks in a range exceeding m, or 2 to
It has a peak in the range of 5 μm and a shoulder in the range exceeding 5 μm. Further, silica is preferably produced by a gel method. The pore volume means that measured by the BET method, and the average particle size means that measured by the Coulter counter method.

The content of silica containing 50% by weight or more of silica having a pore volume of 0.9 to 1.5 ml / g and an average particle size of 2 to 5 μm in the ink receiving layer is 40 to 70% by weight, Particularly, 45 to 60% by weight is preferable. If the content is less than this range, the ink absorbency / dryability tends to decrease, and conversely, if the content exceeds the range, the strength of the ink receiving layer tends to decrease.

The calcium carbonate contained together with silica as a filler in the ink receiving layer is an aragonite calcium carbonate, and particularly preferably, the average particle diameter is 2 to 6.
It has a sea urchin shape that is three-dimensionally intertwined with
The oil absorption is 80 to 110 ml / 100 g. The content of aragonite calcium carbonate in the ink receiving layer is preferably 5 to 25% by weight, particularly preferably 8 to 20% by weight. If the content is less than this range, the image tends to bleed, and conversely, if it is more than this range, the water resistance of the ink receiving layer tends to decrease.

In the ink receiving layer, one or more kinds of fillers other than silica and calcium carbonate can be mixed and used within a range that does not impair the effects of the present invention. Examples of the filler include talc, clay, diatomaceous earth, aluminum hydroxide, polystyrene, polymethacrylate, titanium oxide, calcined kaolin and the like. The content ratio of the entire filler in the ink receiving layer is 45 to 95.
%, Especially 53 to 80% by weight is preferred. If the filler is less than this range, the ink absorbency tends to be insufficient,
On the other hand, if the amount is more than this range, the strength of the ink receiving layer tends to decrease.

The content of silanol-modified polyvinyl alcohol contained in the ink receiving layer as a binder in the ink receiving layer is preferably 20 to 50% by weight, more preferably 25 to 35% by weight. When the content is less than this range, the strength of the ink receiving layer tends to decrease, and conversely, when the content is more than this range, the ink absorbability and drying property of the ink receiving layer tend to decrease.

As the binder, one or two or more binders other than silanol-modified polyvinyl alcohol can be mixed and used as long as the effect of the present invention is not impaired. As such a binder, for example, polyvinyl butyral, gelatin, polyvinyl acetal, carboxymethyl cellulose, polyvinyl pyrrolidone, polyester, acrylic resin, urethane resin and their copolymers,
Examples thereof include styrene-acrylic copolymer, ethylene-vinyl acetate copolymer and the like. Content of the entire binder in the ink receiving layer (solid content in the ink receiving layer)
Is preferably 20 to 50% by weight, and particularly preferably 25 to 35% by weight.

The content of the hydrated aluminum oxide contained in the ink receiving layer in the ink receiving layer is preferably 2 to 15% by weight, more preferably 3 to 7% by weight. When the content is less than this range, the water resistance of the ink receiving layer tends to be lowered, and conversely, when the content is more than this range, the curl of the recording sheet tends to be strong.

If necessary, the ink-receiving layer contains an antifoaming agent, an antistatic agent, an ultraviolet absorber, an optical brightening agent, an antiseptic agent, a pigment dispersant, and an increasing agent as long as the object of the present invention is not impaired. Various additives such as a sticky agent can be contained. Further, the ink receiving layer is excellent in the bleeding prevention performance and the image density, but the bleeding prevention performance can be further improved by further containing a slight amount of a cationic substance. Examples of such cationic substances include dicyandiamide, dimethylamine epichlorohydrin, polyamine resins, and quaternary ammonium salts. To contain the cationic substance, it is appropriate to adopt a method of impregnating the layer formed by coating and drying an ink receiving layer forming material other than the cationic substance with the cationic substance. The method of impregnating the layer includes a method of immersing the layer in a solution containing a cationic substance, a method of applying a solution containing a cationic substance to the layer, a method of spraying a solution containing a cationic substance on the layer, and the like. However, in terms of ease of operation,
A method of applying a solution containing a cationic substance to the layer is preferable. When coating, conventionally known methods such as reverse roll coating, air knife coating, gravure coating and blade coating can be used.

Although the cationic substance is impregnated in the layer, it is preferable that the cationic substance is localized so as to be abundant in the upper portion of the layer. For that purpose, the coating solution should be diluted with water, a mixed solution of a water-soluble organic solvent and water to 1 to 15% by weight, particularly 3 to 6% by weight, and to be a solution containing no binder. Is preferable, and the coating liquid amount is 0.4 to 10 in terms of solid content weight of the cationic substance.
It is preferably 1.2 g / m ² . If the amount of the cationic substance is less than this range, image bleeding tends to occur and the image density tends to decrease, while if it is more than this range, the water resistance of the image tends to decrease. The thickness of the ink receiving layer is 20 to 50 μm, and particularly 25 to
The range of 40 μm is preferable. When the thickness is less than this range, the ink absorbing layer tends to deteriorate in ink absorbency and dryness,
On the other hand, if the thickness is larger than this range, the strength and water resistance of the ink receiving layer are likely to decrease.

The ink jet recording sheet of the present invention may be provided with a layer other than the ink receiving layer as long as the object of the present invention is not impaired. For example, an anchor coat layer may be provided in order to improve the adhesion between the base material and the ink receiving layer. The ink-receiving layer is formed by applying a coating solution obtained by dissolving or dispersing the constituent components in a suitable solvent by a known method such as reverse roll coating, air knife coating, gravure coating, blade coating, and drying. be able to.

[0021]

EXAMPLES Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. The performance of the inkjet recording sheet was evaluated according to the following procedure. In addition, printing was performed with an inkjet printer (model name: MC9000) manufactured by Seiko Epson Corporation using genuine pigment type ink.

(1) Water resistance of the ink receiving layer (scratch resistance in a wet state) With a cotton swab sufficiently wet, the surface of the ink receiving layer of the ink jet recording sheet is adjusted so that the load is 100 g. Was rubbed until it detached, and the number of times required for it was counted. In addition, one round trip (one way 50 mm) was counted as once. The operation was performed up to 100 times, and the number of times when the ink receiving layer was not detached at that time was 100 times.

(2) Strength of ink receiving layer Cellophane tape (“CT manufactured by Nichiban Co., Ltd.” is placed on the ink receiving layer.
405A-18 ", length 10 cm) was pasted with 3 kg of 2 kg pressure rolls, and the degree of peeling when peeling in the direction opposite to the angle of 45 ° was evaluated according to the following criteria. ◯: Area of coating layer adhered to cellophane tape is 30% or less Δ: Area of coating layer adhered to cellophane tape is more than 30% and 60% or less ×: Area of coating layer adhered to cellophane tape is 60% Super

(3) Water resistance of image (dripping) Black of cyan, magenta, yellow and black mixed color is solidly printed, and after 5 minutes of printing, one drop of distilled water is dropped on the printing part with a dropper so that the distilled water is completely absorbed. The degree of ink outflow was visually observed and evaluated according to the following criteria. ◎: No outflow ○: Some outflow occurred, but there was no problem in practical use △: Outflow occurred, there was a problem in practical use ×: Many outflow occurred, there was a practical problem

(4) Image density Cyan, magenta, and yellow colors and mixed color black (mixed color of cyan, magenta, yellow, and black)
Is printed solidly, and the reflection density of the image is measured by Macbeth densitometer RD-
It was measured at 918.

(5) Anti-bleeding performance Using red (mixed color of magenta and yellow) and green (mixed color of cyan and yellow), matte printing mode (rank of ink jetting amount in the used printer modes) Ink ejection amount 17
The state of ink bleeding when a blank character was printed at 0% was visually observed and evaluated according to the following criteria. ◎: No bleeding ○: Some bleeding occurred, but there was no problem in practical use △: Bleeding occurred and there was practical problem ×: Many bleeding occurred, there was practical problem

Example 1 As a base material, YUPO FPG80 [trade name, having a thickness of 80 μm,
A white foamed polypropylene film and a micro void film manufactured by YUPO Corporation were used. A uniform mixture of the following components was used as an anchor coating liquid. (a) ACRONAL YJ-6221D [trade name, BASF
Dispersion Co., Ltd. acrylic resin, solid content concentration 4
9% by weight, anionic] 60 parts by weight (b) Callite SA [trade name, calcium carbonate manufactured by Shiraishi Central Research Institute, solid content concentration 100% by weight, aragonite]
10 parts by weight (c) 30% by weight of water

A uniform mixture of the following components was used as the coating liquid for the ink receiving layer. (1) Silysia 440 [trade name, silica manufactured by Fuji Silysia Chemical Ltd., solid content concentration 100% by weight, average particle diameter 3.5 μm, pore volume 1.25 ml / g] 6.0 parts by weight (2) Silojet P412 [trade name, Grace Davison
Silica, solid content concentration 100% by weight, average particle size 6 to
8 μm, pore volume 2.05 ml / g] 2.4 parts by weight (3) Callite SA [trade name, calcium carbonate manufactured by Shiraishi Central Research Institute, solid content concentration 100% by weight, aragonite,
Average particle diameter of about 3 μm, shape: sea urchin three-dimensionally intertwined, oil absorption 95 ml / 100 g] 2.2 parts by weight (4) R polymer R-1130 [silanol-modified polyvinyl alcohol manufactured by Kuraray Co., Ltd., solid content] Concentration 100% by weight] 4.9 parts by weight (5) Alumina sol 200 [trade name, Nissan Chemical Industries, Ltd.
Made hydrated aluminum oxide, solid content concentration 10% by weight]
7.6 parts by weight (6) Water 76.7 parts by weight

Anchor coat coating liquid is applied on the base material to form an anchor coat layer having a thickness of 3 μm (after drying), and the ink receiving layer coating liquid is applied thereon. , Thickness 3
An inkjet recording sheet was produced by forming an ink receiving layer having a thickness of 0 μm (after drying).

Example 2 Silojet P412 in a coating liquid for an ink receiving layer
[Silica] 2.4 parts by weight of Silysia 440 [silica]
An ink jet recording sheet was produced in the same manner as in Example 1 except that 2.4 parts by weight, that is, 8.4 parts by weight of Silysia 440 [silica] was used as silica.

Example 3 Exactly the same as Example 1, and the thickness is 30 μm (after drying).
After forming the ink receiving layer of
A solution containing a cationic substance (dicyandiamide condensate) was applied to the ink receiving layer so that the solid content of the cationic substance in the ink receiving layer was 3% by weight. This solution did not form a new layer. (A) Neofix E117 [trade name, Nika Kagaku Co., Ltd.
Manufactured dicyandiamide condensate, solid content concentration 50% by weight] 9
Part by weight (b) Water 91 parts by weight

Comparative Example 1 Callite SA [calcium carbonate] in Example 2
Instead of 2.2 parts by weight, light calcium carbonate [calcium carbonate manufactured by Maruo Calcium Co., solid content concentration 100% by weight,
Calcite quality, average particle size about 1-2 μm, oil absorption 50 m
1/100 g] Example 2 except that 2.2 parts by weight were used.
An ink jet recording sheet was produced in the same manner as in.

Comparative Example 2 Callite SA [calcium carbonate] in Example 2
An inkjet recording sheet was produced in the same manner as in Example 2 except that 2.2 parts by weight was not used.

Comparative Example 3 An ink jet recording sheet was prepared in the same manner as in Example 2 except that 7.6 parts by weight of alumina sol 200 [hydrated aluminum oxide] in Example 2 was not used.

Comparative Example 4 Instead of 8.4 parts by weight of Sylysia 440 [silica] in Example 2, Mizukasil P78F [trade name, silica manufactured by Mizusawa Chemical Co., Ltd., solid content concentration 100% by weight, average particle size 12. 5 μm, pore volume 1.65 ml / g] An ink jet recording sheet was produced in the same manner as in Example 2 except that 8.4 parts by weight was used.

Comparative Example 5 In the coating liquid for the ink receiving layer of Example 2, 2.2 parts by weight of Callite SA [calcium carbonate] was not used, and the coating liquid for the ink receiving layer had a dicyandiamide condensation product [ Nichika Chemical Co., Ltd., trade name: Neofix E11
7, solid content concentration 50% by weight, water-soluble cationic substance]
An inkjet recording sheet was produced in the same manner as in Example 2 except that 4.1 parts by weight was mixed.

For each of the ink jet recording sheets obtained in Examples 1 to 3 and Comparative Examples 1 to 5, the water resistance of the ink receiving layer (rubbing resistance in a wet state), the strength of the ink receiving layer, the image Of water resistance (dripping), image density, and bleeding prevention performance were evaluated, and the results are shown in Table 1.

[0038]

[Table 1]

[0039]

The effect of the invention is that the pore volume is 0.9 to 1.5 ml / g,
The ink jet recording sheet of the present invention provided with an ink receiving layer containing silica containing 50% by weight or more of silica having an average particle diameter of 2 to 5 μm, aragonite calcium carbonate, silanol modified polyvinyl alcohol and hydrated aluminum oxide. Has the basic characteristics of conventional ink jet recording sheets, but is particularly suitable for outdoor use such as posters, because it is excellent in the water resistance and strength of the ink receiving layer and the image density and water resistance. Is.

Claims (4)

[Claims] 1. An ink receiving layer is provided on a substrate, and the ink receiving layer contains silica, aragonite calcium carbonate, silanol-modified polyvinyl alcohol and hydrated aluminum oxide, and the silica is , The pore volume is 0.9 to 1.5 ml / g, and the average particle size is 2 to 5 μ.
An ink jet recording sheet, which comprises 50% by weight or more of m silica. 2. The silica has a pore volume of 0.9-1.
50 ml of silica having an average particle size of 2 to 5 μm at 5 ml / g
˜90% by weight, the pore volume exceeds 1.5 ml / g and 2.
The inkjet recording sheet according to claim 1, which is a silica containing 10 to 40% by weight of silica having an average particle size of 5 μm or less at 2 ml / g or less. 3. The content of silica in the ink receiving layer is 40.
-70% by weight, the content of aragonite calcium carbonate is 5 to 25% by weight, the content of silanol-modified polyvinyl alcohol is 20 to 50% by weight,
The inkjet recording sheet according to claim 1, wherein the content of the hydrated aluminum oxide is 2 to 15% by weight. 4. The ink jet recording sheet according to claim 1, which is for a water-based ink using a pigment as a coloring material.