JP2002254798A - Material for inkjet recording - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a material for inkjet recording that can prevent blocking without getting air bubbles mixed at the time of laminating a protective film. SOLUTION: The material for the inkjet recording 3 having an ink receiving layer 2 on a backing 1 has a surface of the ink receiving layer 2 whereon the number of a convex part at a height of more than 5 μm is more than 50 per 1 mm<2> and the number of a convex part at a height of more than 10 μm is less than 10 per 1 mm<2> .

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording material for an ink jet printer, and more particularly to a recording material suitable for laminating a protective film.

[0002]

2. Description of the Related Art In recent years, digitization has become widespread, and opportunities for outputting digital data such as image images from computers have been increasing. There are various output methods such as dot impact and laser.
Among them, the ink jet recording method has been widely used because of its advantages such as low hardware and running cost, and the possibility of color output.

The performance required of such an ink jet recording material is not only that it can be simply recorded by an ink jet printer, but also that it is often stored in a laminated state after recording. , "Blocking").

[0004] In order to prevent blocking, means for improving the ink absorption rate and improving the amount of undried ink by improving the binder resin have been used, but the blocking has not been sufficiently prevented. Therefore, it is common practice to include a pigment in the ink receiving layer and to provide a surface with irregularities to prevent blocking.

On the other hand, when the ink-jet recording material after image recording is used in the field of graphic arts, especially when used outdoors, a protective film is laminated on the recording surface to impart durability and weather resistance to the image. It is common to be done.

[0006]

However, when a protective film is laminated on an ink jet recording material containing a pigment in the ink receiving layer as described above, air bubbles are mixed during lamination and the appearance of an image becomes poor. If a small hole is made in the surface of the protective film to remove the mixed air bubbles, there is a problem that the image deteriorates due to rainwater entering from the place.

Accordingly, an object of the present invention is to provide an ink jet recording material capable of preventing blocking without air bubbles when laminating a protective film and preventing blocking.

[0008]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies in order to solve the above-mentioned object, and as a result, have found that the inclusion of bubbles is caused by a high elevation on the surface of the ink receiving layer. . Then, as a result of earnestly studying a surface shape capable of preventing blocking without mixing bubbles, they were completed.

That is, in the ink jet recording material of the present invention, the surface of the ink receiving layer has a height of 5 μm in an ink jet recording material having an ink receiving layer on a support.
m is 50 or more per 1 mm ² of convex parts,
The number of protrusions having a height of 10 μm or more is less than 10 per 1 mm ² .

Preferably, the ink receiving layer comprises at least a binder resin and a pigment, and includes a urethane resin as the binder resin and urethane resin beads as the pigment.

Preferably, the average particle diameter of the urethane resin beads is not less than -6 μm and less than 8 μm with respect to the thickness of the ink receiving layer.

[0012] Preferably, the content of the urethane resin beads is equal to or less than the binder resin 1 constituting the ink receiving layer.
The amount is 0.1 to 10 parts by weight with respect to 00 parts by weight.

[0013] Preferably, the support is a roughened support.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The ink jet recording material of the present invention has an ink receiving layer on a support, and the surface of the ink receiving layer has a convex portion having a height of 5 μm or more per 1 mm ^2. The number of protrusions is 50 or more, and the number of protrusions having a height of 10 μm or more is less than 10 per 1 mm ² . Hereinafter, embodiments of each component will be described.

FIGS. 1 to 4 are views showing an embodiment of the ink jet recording material 3 of the present invention. 1 to 3
The ink jet recording material 3 is composed of a support 1, a binder resin 21, and an ink receiving layer 2 composed of a pigment 22. In addition, in FIG. 1 to FIG.
Indicates the thickness of the ink receiving layer. The ink jet recording material 3 shown in FIG.
Consists of

The support can be used without any particular limitation, but plastic films such as polyester, polycarbonate, polyvinyl chloride, polyethylene, polypropylene and polystyrene are preferably used. Although the thickness of the support is not particularly limited, a support having a thickness of 5 to 300 μm is preferably used from the viewpoint of transportability to an ink jet printer.

The ink receiving layer is mainly composed of a binder resin, and mainly has a role of receiving an ink jet ink.

The binder resin is mainly composed of a water-soluble resin and a hydrophilic resin generally used as a binder resin for the ink receiving layer. Examples of such a water-soluble or hydrophilic resin include albumin, gelatin, casein, starch, arabic gum, natural resins such as sodium alginate, carboxymethylcellulose, hydroxyethylcellulose, polyamide, polyacrylamide,
Synthetic resins such as polyhydroxyethyl methacrylate, polyphenyl acetoacetal, polyvinyl acetal, polyvinyl formal, polyethylene imine, polyvinyl pyrrolidone, melamine resin, polyurethane, polyvinyl alcohol, polyester, sodium polyacrylate, acrylate copolymer and the like. These can be used alone or in combination of two or more.

On the surface of the ink receiving layer, the number of projections having a height of 5 μm or more is 50 or more per 1 mm ² , and the height is 10 μm.
The number of protrusions of μm or more is less than 10 per 1 mm ² . Blocking can be prevented by setting the number of protrusions having a height of 5 μm or more to 50 or more per 1 mm ² , and reducing the number of protrusions having a height of 10 μm or more to less than 10 per 1 mm ² during lamination of the protective film. It is possible to prevent air bubbles from being mixed. That is, the surface of the ink receiving layer has a protrusion of 5 μm or more in height of 1 mm ^2.
Even if the number of protrusions is 50 or more, if the number of protrusions having a height of 10 μm or more is 10 or more per 1 mm ² , blocking can be prevented but air bubbles cannot be mixed. Further, even if the surface of the ink receiving layer has less than 10 convex portions having a height of 10 μm or more per 10 mm ² ,
When the number of the above convex portions is not 50 or more per 1 mm ² , air bubbles can be prevented from being mixed, but blocking cannot be prevented.

It is to be noted that the height on the surface of the ink receiving layer is 5 μm.
m or more, the number of protrusions is more preferably 1 per mm ^2.
Desirably, the number is from 00 to 1000. When the number is 100 or more, blocking can be more effectively prevented, and when the number is less than 1000, a decrease in gloss of the surface of the ink receiving layer is prevented, and an inkjet recording material suitable for the field of graphic arts is provided. can do.

The height and the number of the convex portions on the surface of the ink receiving layer are measured by a stylus type three-dimensional surface roughness measuring device (SA).
(S-2010 SAU-II: Meishin Koki Co., Ltd.) to measure the number of “mountain peak counts”. Specifically, a constant reference level is provided in the positive direction from the average line of the obtained data extraction curve (when measuring the number of protrusions having a height of 5 μm or more, the reference level is set to 5 μm). The number of points (mountain peak counts) that exceeded the reference level after falling to the negative side from the average line was defined as the number of protrusions having a certain height or more.

The thickness of the ink receiving layer is selected in the range of 2 to 50 μm, preferably 5 to 30 μm. When the thickness is 2 μm or more, the ink absorptivity can be made sufficient, and when the thickness is 50 μm or less, the occurrence of curling can be prevented.

In order to impart the surface shape as described above to the surface of the ink receiving layer, a method of adding a pigment to the ink receiving layer (FIGS. 1 to 3) is used. A method of forming (FIG. 4) and the like can be mentioned, but a method of adding a pigment to the ink receiving layer is preferable. The roughened support can be obtained by sandblasting in which fine sand is blown onto the support surface at high speed, chemical etching in which the support surface is treated with a chemical, formation of a mat layer on the support surface, and the like. .

When a pigment is added to the ink receiving layer, the pigment to be added includes silica, clay, talc, diatomaceous earth, calcium carbonate, calcium sulfate, barium sulfate, aluminum silicate, titanium oxide, zinc oxide, synthetic zeolite, In addition to inorganic pigments such as alumina and smectite, organic pigments such as styrene resin beads, urethane resin beads, benzoguanamine resin beads, silicone resin beads, and acrylic resin beads can be used. These may be used alone or in combination of two or more. be able to.

Although the average particle size of the pigment is not necessarily unconditional, it is not less than −6 μm and less than +8 μm, preferably −3 μm, with respect to the thickness of the ink receiving layer.
It is desirably at least m and less than 5 μm. For example, when the thickness of the ink receiving layer is 20 μm, the average particle size of the pigment is preferably 14 to 28 μm, and more preferably 17 to 25 μm. By setting the average particle diameter in the range of −6 μm or more to less than +8 μm with respect to the thickness of the ink receiving layer, it is possible to form a projection having a height of 5 μm or more that can prevent blocking, and to cause bubbles. It is possible to make it difficult to form a projection having a height of 10 μm or more. Here, in order to facilitate the control of the surface shape, it is preferable that the particle size distribution of the pigment is narrow. In addition, the thickness of the ink receiving layer in the present invention means “a” in FIGS. 1 to 3.

The amount of the pigment added is 0.1 to 10 parts by weight per 100 parts by weight of the binder resin constituting the ink receiving layer.
It is desirable that the amount be in the range of 0.5 to 5 parts by weight. When the amount is 0.1 parts by weight or more, blocking can be prevented, and when the amount is 10 parts by weight or less, a decrease in gloss on the surface of the ink receiving layer is prevented, and the inkjet recording material is suitable for the field of graphic arts. can do.

When the pigment is added to the ink receiving layer, the above-mentioned desired surface shape cannot always be obtained just because the average particle size and the amount of the pigment are within the above-mentioned ranges. Absent. The obtained surface shape differs depending on the types of the binder resin and the pigment constituting the ink receiving layer. Although the cause is not clear, it is considered that the difference in the specific gravity between the binder resin and the pigment has an influence.

Here, it is desirable to use urethane resin as a binder resin and urethane resin beads as a pigment. First, by using urethane resin as a binder resin and urethane resin beads as a pigment, the above-described surface shape can be easily obtained. This is probably because the pigment is uniformly dispersed in the ink receiving layer because the components of the binder resin and the pigment are the same system. Second, by using urethane resin as a binder resin and urethane resin beads as a pigment, air bubbles can be completely prevented from being mixed during lamination. This is because urethane resin has excellent flexibility, so urethane resin beads sink into the binder resin consisting of urethane resin due to the pressure during lamination, and the urethane resin beads themselves are slightly deformed. It is considered that the cause is that the protrusions having a height of 10 μm or more are completely eliminated on the surface of the layer. In other words, by using urethane resin as a binder resin and urethane resin beads as a pigment, even if the ink receiving layer before lamination had 1 to 9 protrusions with a height of 10 μm or more per 1 mm ² , the lamination Sometimes 10 μm high
It is considered that the cause is that the above-mentioned protrusions have completely disappeared.

When urethane resin is used as the binder resin and urethane resin beads are used as the pigment, more preferably, the average particle size and the amount of the urethane resin beads are set in the above-mentioned ranges (average particle size: thickness of the ink receiving layer). On the other hand, minus 6 μm or more and less than plus 8 μm, preferably minus 3 μm or more and less than plus 5 μm.
0.1 to 10 parts by weight, preferably 0.5 to 5 parts by weight, based on 100 parts by weight of the binder resin constituting the ink receiving layer. ) Is desirable.

Additives such as a leveling agent, an ultraviolet absorber, an antioxidant, a chelating agent, and an antistatic agent can be added to the ink receiving layer as long as the above performance is not impaired.

As a method for forming the ink receiving layer, for example, the above-mentioned binder resin, pigment and additives to be added as necessary are dissolved or dispersed in an appropriate solvent to prepare a coating liquid, and the coating liquid is prepared. Is applied on a support by a known method such as a roll coating method, a bar coating method, a spray coating method, an air knife coating method, and the like, and a method of hot melt coating the above mixture.

In the ink jet recording material of the present invention, the above-mentioned ink receiving layer needs to be on the outermost surface side of the ink jet recording material, but the ink receiving layer may have another ink receiving layer between the ink receiving layer and the support. The layer may be composed of two or more layers.

Further, an anchor coat layer is provided between the ink receiving layer and the support to adjust the adhesiveness of the ink receiving layer, and the ink receiving layer is opposite to the ink receiving layer of the support to prevent curling. It is no problem to provide a back coat layer on the side surface.

Further, in order to prevent charging at the time of discharge from the ink jet printer, an antistatic layer may be provided on the surface of the support opposite to the ink receiving layer or between the ink receiving layer and the support. . Since the antistatic layer is only required to be very thin, even if it is provided on the ink receiving layer, the above performance is not particularly impaired.

As described above, according to the present invention, the surface of the ink receiving layer has a protrusion of 5 μm or more in height of 1 mm ^2.
The number of protrusions having a height of 10 μm or more is less than 10 per 1 mm ² . This prevents bubbles from entering when laminating the protective film,
Blocking can be prevented.

[0036]

The present invention will be further described with reference to the following examples.
Note that “parts” and “%” are based on weight unless otherwise specified.

Example 1 A 100 μm-thick transparent polyester film (Lumilar T60: Toray Industries, Inc.) was dried to a thickness of 2 after drying an ink receiving layer coating liquid having the following composition.
It was applied by a bar coating method so as to have a thickness of 0 μm and dried to form an ink receiving layer, thereby obtaining an ink jet recording material.

<Coating liquid for ink receiving layer> 6 parts of hydrophilic acrylic resin (Chemry LH-448: Soken Chemical Co., Ltd.) 0.2 parts of urethane resin beads (average particle size 21 μm) (Art Pearl C300: Negami Kogyo)・ 90 parts of water

Example 2 On a 100 μm-thick transparent polyester film (Lumilar T60: Toray Industries, Inc.), an ink receiving layer coating liquid having the following composition was dried to a thickness of 2 μm.
It was applied by a bar coating method so as to have a thickness of 0 μm and dried to form an ink receiving layer, thereby obtaining an ink jet recording material.

<Coating liquid for ink receiving layer> 10 parts hydrophilic urethane resin (Pateracol IJ-70: Dainippon Ink and Chemicals, Inc.) 0.2 parts urethane resin beads (average particle diameter 21 μm) 0.2 parts (Artpearl C300) : Negami Industry Co., Ltd.) ・ 90 parts of water

Comparative Example 1 The pigment of Example 1 was replaced with acrylic resin beads (Art Pearl G800: Negami Kogyo Co., Ltd., average particle size 6).
μm) to obtain an ink jet recording material in the same manner as in Example 1.

Comparative Example 2 The pigment of Example 2 was replaced with acrylic resin beads (Art Pearl G300: Negami Kogyo Co., Ltd., average particle size 2).
An ink jet recording material was obtained in the same manner as in Example 2 except that the thickness was 1 μm).

With respect to the ink jet recording materials obtained in Examples 1 and 2 and Comparative Examples 1 and 2, the surface of the ink receiving layer was measured with a stylus type three-dimensional surface roughness measuring device (SAS-2010 SA).
U-II: Meishinkoki Co., Ltd.) was used to count the number of “mountain peak counts”. Table 1 shows the results. The measurement range is 1.024 mm (X axis) × 0.400 mm (Y
Axis), and the measurement pitch of the Y axis was 5 μm.

[0044]

[Table 1]

The following items were evaluated for the ink jet recording materials obtained in Examples and Comparative Examples. Table 2 shows the results.

(1) Blocking Printing was performed using an ink jet printer (PM750C: Seiko Epson), and a polyester film (Lumirror T60: Toray) was laminated on the printing surface after 12 hours. After that, as a result of rubbing the laminated polyester film with a hand, “も の” indicates that the film was not blocked, and “X” indicates that the film was blocked. (2) Bubble mixing A laminator (SR-IV M.
Protective film (Duratect) using KK
After laminating PVG80Y (Kimoto Co.), the state of air bubbles was visually evaluated. As a result, "◎" indicates that no air bubbles were mixed, "O" indicates that almost no air bubbles were mixed, and "X" indicates that many air bubbles were mixed.

[0047]

[Table 2]

In Example 1, the surface of the ink receiving layer had 50 or more protrusions with a height of 5 μm or more per 1 mm ² , and the number of protrusions with a height of 10 μm or more was 10 or more per 1 mm ^2. It is less than pieces. Therefore, blocking can be prevented while preventing air bubbles from being mixed.

In Example 2, the surface shape of the ink receiving layer is the same as that of Example 1, but urethane resin is used as the binder resin and urethane resin beads are used as the pigment. Therefore, blocking could be prevented while completely preventing air bubbles from being mixed.

In the case of Comparative Example 1, the surface of the ink receiving layer had a height of 10 μm or more in the number of projections per 10 mm ^2.
While the number of protrusions having a height of 5 μm or more is 1 mm
Less than 50 per ² Therefore, although the incorporation of air bubbles can be prevented, blocking cannot be prevented.

In the case of Comparative Example 2, the surface of the ink receiving layer had 50 or more protrusions having a height of 5 μm or more per 1 mm ² , while the surface of the ink receiving layer had 1 mm or more protrusions having a height of 10 μm or more.
It is 10 or more per ² pieces. Therefore, although blocking can be prevented, mixing of air bubbles cannot be prevented.

[0052]

As described above, according to the ink jet recording material of the present invention, the surface of the ink receiving layer has 50 or more protrusions having a height of 5 μm or more per 1 mm ² and a height of 10 μm.
Since the number of protrusions of μm or more is less than 10 per 1 mm ² , blocking can be prevented while preventing air bubbles from being mixed during lamination of the protective film.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing one embodiment of an ink jet recording material of the present invention.

FIG. 2 is a sectional view showing another embodiment of the ink jet recording material of the present invention.

FIG. 3 is a sectional view showing another embodiment of the ink jet recording material of the present invention.

FIG. 4 is a sectional view showing another embodiment of the ink jet recording material of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Support 11 ... Roughened support 2 ... Ink receiving layer 21 ... Binder resin 22 ... Pigment 3 ... Ink jet recording material a ... Ink receiving Layer thickness

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Tomokazu Takahashi 4-6-35 Suzuya, Yono-shi, Saitama F-term in Kimoto R & D Center (reference) 2C056 EA13 FC06 HA44 2H086 BA15 BA17 BA33 BA34 BA44 BA45 4J038 DG001 DG002 EA011 KA08 KA20 NA01 NA10 PB11

Claims (5)

[Claims] 1. An ink jet recording material having an ink receiving layer on a support, wherein the surface of the ink receiving layer is
An ink jet recording material, wherein the number of protrusions having a height of 5 μm or more is 50 or more per 1 mm ² , and the number of protrusions having a height of 10 μm or more is less than 10 per 1 mm ² . 2. The ink-jet recording method according to claim 1, wherein the ink receiving layer is composed of at least a binder resin and a pigment, and includes a urethane resin as the binder resin and urethane resin beads as the pigment. Recording material. 3. The ink jet recording material according to claim 2, wherein the average particle diameter of the urethane resin beads is not less than −6 μm and less than 8 μm with respect to the thickness of the ink receiving layer. 4. The ink jet recording material according to claim 2, wherein the content of the urethane resin beads is 0.1 to 10 parts by weight based on 100 parts by weight of the binder resin constituting the ink receiving layer. . 5. The ink jet recording material according to claim 1, wherein said support is a roughened support.