JP3300680B2 - Inkjet recording paper - Google Patents

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 recording using an ink comprising a water-soluble dye, and more particularly to an ink-jet recording sheet which is excellent in ink absorption and coloring, image light fastness and image water fastness. .

[0002]

2. Description of the Related Art The ink jet recording method is a method of forming an image by flying ink droplets by various methods, so that it is easy to achieve high speed and full color, and the apparatus is inexpensive. I'm doing it. In particular, recent full-color inkjet printers have realized high resolution and high gradation comparable to silver halide photography as a result of the miniaturization of ink droplets and the improvement of ink significantly, and digital images taken with a digital camera etc. The number of users who directly print with an inkjet printer is also increasing. In addition, since the recorded images are of high quality, they are often posted or stored for a long period of time. The demand for light fastness is increasing.

However, when recording is performed on an ordinary inkjet recording paper by an inkjet printer,
The recorded image is discolored by ultraviolet rays included in irradiation light such as sunlight or fluorescent light. Therefore, in order to improve long-term storage,
A method using a pigment ink or the like which is relatively resistant to fading due to ultraviolet rays may be employed. However, from the viewpoint of sharpness of color development, it is often attempted to improve image light fastness using a dye ink system.

Means for improving image light fastness include, for example, a method of adding an ultraviolet absorber such as a benzophenone type or a benzotriazole type (JP-A-57-87988 and JP-A-63-222885). A method of adding a hindered amine-based antioxidant (JP-A-61-146)
No. 5913) and a method using a combination of zinc oxide powder and a cationic polymer electrolyte (Japanese Patent Application Laid-Open No. 7-32725) have been proposed, but in these cases, it is difficult to disperse them uniformly. For this reason, a sufficient effect on image light fastness has not been obtained, and it has not always been sufficient in terms of improving image quality.

As means for realizing higher image quality (higher quality) by improving glossiness, for example, a method using cationic colloidal silica (JP-A-6-92)
No. 011) has been proposed, but has the disadvantage that the balance between high image quality and image storability is not satisfactory. Further, as an attempt to improve the water resistance of the recording layer, a method of providing a coating layer comprising a water-dispersible polymer, colloidal silica in a bead-like shape, and a water-soluble polymer (JP-A-5-51469) is known. Although it has been proposed, it has not yet achieved a sufficient effect on the water fastness of an image recorded by an ink jet printer, and also has an insufficient light fastness of the image.

[0006]

SUMMARY OF THE INVENTION Accordingly, the present invention relates to a recording material for recording using an ink comprising a water-soluble dye, and particularly to a recording material having excellent ink absorbency, color development, image light fastness, and image water fastness. It is another object of the present invention to provide an ink jet recording sheet which is excellent in ink jet recording quality and has a moderate glossiness.

[0007]

SUMMARY OF THE INVENTION The above objects of the present invention are as follows.
An intermediate layer mainly composed of anionic colloidal silica and zinc oxide fine particles having an average particle diameter of 15 to 380 nm as a main component, and a cationic colloidal silica and a cationic polymer electrolyte as main components on an ink-receiving support. This has been attained by an ink jet recording paper characterized by comprising a fixing layer.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The ink-receptive support in the present invention means a sheet-like support capable of absorbing an ink composed of a water-soluble dye. In particular, a pigment and a binder are provided on a base paper. It is preferable to use a support provided with an ink receiving layer as a main component. The base paper is mainly composed of papermaking pulp. As papermaking pulp, LBKP, N
Chemical pulp such as BKP and the like, mechanical pulp such as GP and TMP, and waste paper pulp may be mentioned. However, the present invention is not particularly limited thereto, and these pulp may be used alone or in combination as needed. Can be used.

The filler, sizing agent, and various internal chemicals such as a paper strength enhancer to be added to the base paper are not particularly limited, and may be appropriately selected from known fillers and various internal chemicals. Can be used. Also, starch or surface sizing agent may be size-pressed or coated, and if necessary, defoamer, pH adjuster, dye or color pigment for adjusting hue, improve visual whiteness For this purpose, a fluorescent dye or the like can be further used.

The ink receiving layer provided on these base papers is
Preferably the amount of coating is 5 to 25 g / ^{m 2} by solid content, it is particularly preferable to provide 7~20g / ^{m 2.} If the ink receiving layer is less than 5 g / m ² , sufficient ink absorbency cannot be obtained and bleeding or the like may occur. On the other hand, if the ink receiving layer exceeds 25 g / m ² , the ink absorption capacity becomes excessive, so that the recording density is lowered and it is difficult to obtain high quality image.

The ink receiving layer usually comprises a pigment and a binder as main components. Examples of the pigment in this case include light and heavy calcium carbonate, kaolin, clay, talc, titanium dioxide, zinc oxide, satin white, Magnesium silicate, calcium silicate, aluminum silicate, aluminum hydroxide, alumina, pseudoboehmite, synthetic amorphous silica,
White pigments such as magnesium carbonate and zeolite are preferred. In the present invention, it is particularly preferable to use synthetic amorphous silica as a pigment for the ink receiving layer in consideration of the balance between the ink coloring properties, absorption properties, and cost.

The binder used for the ink receiving layer is as follows:
There is no particular limitation as long as it has a strong adhesive force to the base paper and forms a film after drying. Such binders include oxidized starch, esterified starch, enzyme-modified starch, starches such as cationized starch, various polyvinyl alcohols having different degrees of saponification and derivatives thereof,
Casein, soy protein, carboxymethylcellulose, cellulose derivatives such as hydroxyethylcellulose, styrene-acrylic resin, isobutylene-maleic anhydride resin, acrylic emulsion, vinyl acetate emulsion, vinylidene chloride emulsion, polyester emulsion, styrene-butadiene latex, acrylonitrile butadiene latex And the like.

In the ink receiving layer, if necessary, an antifoaming agent, a surface sizing agent, a water-proofing agent, a pH adjusting agent, an ultraviolet absorber, an antioxidant, a dye for adjusting the hue and a colored Pigments, fluorescent dyes, and the like can be appropriately used in a range that does not impair the effects of the present invention. In the present invention, it is preferable to add a known cationic dye fixing agent to the ink receiving layer in order to improve the water resistance of the image.

The intermediate layer provided on the ink receptive support has an average particle size of 15 to 380 nm for absorbing ultraviolet rays in order to achieve both image light fastness and ink absorptivity.
m of zinc oxide fine particles and anionic colloidal silica having good compatibility with the zinc oxide fine particles. In the present invention, the zinc oxide fine particles particularly have an average particle diameter of 20 to
It is preferable to use zinc oxide fine particles of 300 nm.
Colloidal silica is a colloidal solution of silica that has been stabilized and made easy to use, as described in “Chemical Handbook Applied Chemistry” (published by Maruzen Co., Ltd. on October 15, 1986, edited by The Chemical Society of Japan). Things.

When the average particle diameter of the zinc oxide fine particles is less than 15 nm, the zinc oxide fine particles affect the fixing layer, and the density of the fixing layer is increased. Not only can not get,
Problems also arise in operation and cost. Conversely, if the average particle diameter of the zinc oxide fine particles exceeds 380 nm, the transparency of the coating layer is impaired by light scattering, the recording density is reduced, and sufficient image light resistance cannot be obtained. The average particle diameter of the zinc oxide fine particles is measured by observing the zinc oxide particles with a transmission electron microscope.

Since the surface of the above-mentioned zinc oxide fine particles necessary for imparting image light fastness is negatively charged, colloidal silica necessary for obtaining ink absorbability includes:
It is necessary to use anionic colloidal silica.
Since the anionic colloidal silica usually has an isoelectric point of around pH 2, it is negatively charged in most of the pH range above, and is very suitable for the present invention. Conversely, cationic colloidal silica formed by adsorbing cations generated by hydrolysis of metal salts on the surface and reversing the charge causes poor operation with zinc oxide fine particles, causing operational problems. . Further, the shape of the anionic colloidal silica is preferably a non-spherical shape in which beads are connected in a bead shape or a ring shape.

The content of the zinc oxide fine particles is preferably in the range of 2 to 25 parts by weight, more preferably in the range of 3 to 20 parts by weight, based on 100 parts by weight of the anionic colloidal silica. preferable. When the content of the zinc oxide fine particles is less than 2 parts by weight, the light resistance of the image may not be sufficiently provided.
If the amount is more than 5 parts by weight, the recording density may decrease, and a high-quality image may not be obtained.

If necessary, the intermediate layer may contain an antifoaming agent, a surface sizing agent, a pH adjuster, an ultraviolet absorber, an antioxidant,
Dyes, colored pigments, fluorescent dyes, and the like for adjusting the hue can be appropriately used together within a range that does not impair the effects of the present invention. The intermediate layer of the present invention has a solid content of 1 to 6 g / m2.
² is preferably provided, and particularly preferably 1.5 to 5 g / m ² . If the intermediate layer is less than 1 g / m ² , it may not be possible to obtain sufficient image light fastness. Conversely, if the intermediate layer exceeds 6 g / m ² , the ink absorption is poor and high quality image quality is obtained. You may not be able to get it.

The outermost fixing layer needs to contain cationic colloidal silica and cationic polymer electrolyte as main components in order to achieve both image water resistance, ink absorbency and high glossiness. From the viewpoint of improving ink absorption, the shape of the cationic colloidal silica is
It is particularly preferable that the particles have a non-spherical shape in which particles are connected in a bead shape or a ring shape. Anionic colloidal silica and synthetic amorphous silica have poor compatibility with the cationic polymer electrolyte, and thus cause operational problems.

The fixing layer is preferably provided with a solid content of 1 to 6 g / m ^2, particularly preferably 1.5 to 5 g / m ² . If the fixing layer is less than 1 g / m ² , sufficient water resistance and glossiness of the image may not be obtained. On the other hand, if the fixing layer exceeds 6 g / m ² , the ink absorption is poor and the quality is high. In some cases, high image quality cannot be obtained.

The content of the cationic polymer electrolyte is from 2 to 25 parts by weight based on 100 parts by weight of the cationic colloidal silica.
It is preferably in the range of parts by weight, particularly preferably in the range of 3 to 20 parts by weight. If the content of the cationic polyelectrolyte is less than 2 parts by weight, the water resistance of the image may not be sufficiently provided. On the contrary, if the content of the cationic polyelectrolyte exceeds 25 parts by weight, the ink absorption may be reduced. Properties and light resistance of the image may be reduced.

The cationic polymer electrolyte used in the present invention includes, for example, dicyandiamide / alkylamine polycondensate, dicyandiamide / formalin polycondensate, polyethyleneimine derivatives, alkylamine (.ammonia).
Epichlorohydrin polycondensate, polymethacrylic acid 4
It can be appropriately selected from known cationic polymer electrolytes such as quaternary ammonium salt derivatives and polydiallyldimethylammonium chloride. In addition, such a cationic polymer electrolyte can be used in combination as appropriate.

In the present invention, by applying a fixing layer containing the above-mentioned cationic colloidal silica and cationic polymer electrolyte as a main component to the outermost layer, it is possible to achieve both image water resistance and high quality of a recorded image. . In particular, when reproducing a silver halide photographic image, the 75-degree specular gloss of the fixing layer surface measured according to JISP8142 is 30%.
It is necessary to be at least 35%, and preferably at least 35%. In the fixing layer, if necessary, an antifoaming agent, a surface sizing agent, a pH adjuster, an ultraviolet absorber, an antioxidant,
Dyes, colored pigments, fluorescent dyes, and the like for adjusting the hue may be used in combination as long as the effects of the present invention are not impaired.

Means for providing an ink receiving layer, an intermediate layer, a fixing layer, and the like on a base paper include known coatings such as various blade coaters, roll coaters, air knife coaters, bar coaters, curtain coaters, gravure coaters, and gate roll coaters. Processing equipment can be used. Further, as the surface finish, various calenders such as a machine calender, a soft calender, and a super calender can be used alone or in combination.

[0025]

The ink jet recording paper of the present invention comprises, on the surface of an ink receptive support, a zinc oxide powder having a constant particle size which absorbs ultraviolet rays and an anionic colloidal silica which is excellent in compatibility with the powder. Having an intermediate layer, and a fixing layer containing cationic colloidal silica as a main component that imparts water resistance and gloss to the image, so that it not only has excellent ink absorption and coloring properties, but also has image light resistance and image water resistance. It is an extremely high-quality recording paper excellent in glossiness and gloss.

[0026]

EXAMPLES The specific structure of the recording sheet of the present invention will be described below with reference to examples, and the characteristics of the recording sheet will be further described in comparison with comparative examples. However, the present invention is limited by these examples. Not something. In the examples, “parts” all represent “parts by weight”. The average of each colloidal silica was 1
The secondary particle diameter is a value measured by the BET method, and the secondary particle length of the non-spherical octionic colloidal silica is a value measured by a laser scattering method.

Embodiment 1 FIG. Freeness 440 ml c. s. f.
93 parts of hardwood bleached kraft pulp (L-BKP) with a freeness of 520 mlc. s. f. Softwood bleached kraft pulp (N-BKP) 7 parts, talc 7 parts, sulfate band 1.5
Parts, a sizing agent of 0.4 parts, and a slurry of 0.02 parts of a retention aid were prepared, paper-making was carried out in a conventional manner with a twin-wire paper machine, followed by pre-drying with a cylinder dryer, and then a 2-roll size press. Using an apparatus, oxidized starch was coated on both sides so that the coating amount of both surfaces combined was 4 g / m ^{2 in} solid content, machine calendering was performed, the smoothness was 35 seconds, and the basis weight was 160 g / m ^2. Base paper was obtained.

On the base paper thus obtained, the following coating solution 1 was solidified at a solid content of 16 g / M using a Meyer bar coater.
After coating so that the m ^2, using a calender device,
An ink receiving layer was provided by treating at a linear pressure of 80 kg / cm, and the intermediate layer and the coating liquid 2 were further coated thereon using a Meyer bar coater so that the following coating liquid 2 and coating liquid 3 became ² g / m ² respectively. After being applied as a fixing layer, it was treated at a linear pressure of 100 kg / cm using a calender, and the basis weight was 180 g / cm2.
to obtain an ink jet recording paper of m ^2.

(Coating liquid 1) Synthetic silica (average secondary particle diameter 4 μm): 100 parts polyvinyl alcohol (PVA117: Kuraray Co., Ltd.)
): 20 parts Dye fixing agent (quaternary ammonium salt type polymer): 5 parts Water: 550 parts

(Coating liquid 2) Anionic spherical colloidal silica (average primary particle diameter 10
To 20 nm): 100 parts Zinc oxide fine particles (average particle diameter 20 nm): 5 parts Water: 420 parts

(Coating liquid 3) Non-spherical (beaded) cationic colloidal silica (average 1)
Secondary particle diameter 10 to 20 nm, secondary particle length 50 to 300 n
m): 100 parts Cationic polymer electrolyte (quaternary ammonium salt type polymer): 5 parts Water: 550 parts

Embodiment 2 FIG. Average particle size 2 used in coating liquid 2
Ink jet recording paper was obtained in exactly the same manner as in Example 1 except that zinc oxide fine particles of 0 nm were replaced with zinc oxide fine particles of 200 nm in average particle diameter.

Embodiment 3 FIG. An ink jet recording paper was obtained in exactly the same manner as in Example 1 except that the content of the zinc oxide fine particles used in the coating liquid 2 was changed to 15 parts.

Embodiment 4 FIG. The coating amount of the coating liquid 2 is 4.5 g / m
^The basis weight was 1 in exactly the same manner as in Example 1 except that
82.5 g / m ² of ink jet recording paper was obtained.

Embodiment 5 FIG. The coating amount of the coating liquid 2 is 10 g / m ²
Except that the basis weight was 18 in the same manner as in Example 1.
8 g / m ² of ink jet recording paper was obtained.

Embodiment 6 FIG. Other than not applying coating liquid 1,
In the same manner as in Example 1, an ink jet recording paper having a basis weight of 164 g / m ² was obtained.

Embodiment 7 FIG. An ink jet recording paper was obtained in exactly the same manner as in Example 1, except that the non-spherical cationic colloidal silica used in the coating liquid 3 was changed to spherical cationic colloidal silica (average primary particle diameter: 10 to 20 nm). .

Comparative Example 1 An ink jet recording paper was obtained in exactly the same manner as in Example 1 except that the zinc oxide fine particles used in the coating liquid 2 were zinc oxide fine particles having an average particle diameter of 520 nm.

Comparative Example 2 Average particle size 2 used in coating liquid 3
Ink jet recording paper was obtained in exactly the same manner as in Example 1, except that zinc oxide fine particles of 0 nm were replaced with zinc oxide fine particles of an average particle diameter of 10 nm.

Comparative Example 3 Other than not applying the coating liquid 2,
In the same manner as in Example 1, an ink jet recording paper having a basis weight of 178 g / m ² was obtained.

Comparative Example 4 Other than not applying the coating liquid 3,
In the same manner as in Example 1, an ink jet recording paper having a basis weight of 178 g / m ² was obtained.

Comparative Example 5 An ink jet recording paper was obtained in exactly the same manner as in Example 1 except that the anionic spherical colloidal silica used in the coating liquid 2 was not blended.

Comparative Example 6 An ink jet recording paper was obtained in exactly the same manner as in Example 1 except that the zinc oxide fine particles used in the coating liquid 2 were not blended.

Comparative Example 7 Example 1 except that the non-spherical cationic colloidal silica used in the coating liquid 3 was not blended.
In the same manner as in the above case, an ink jet recording paper was obtained.

Comparative Example 8 An ink jet recording paper was obtained in exactly the same manner as in Example 1 except that the cationic polymer electrolyte used in the coating liquid 3 was not blended.

Comparative Example 9 An ink jet recording paper was obtained in exactly the same manner as in Example 1 except that synthetic silica (average secondary particle diameter: 4 μm) was used instead of the spherical anionic colloidal silica used in the coating liquid 2.

The evaluation results of the ink jet recording papers obtained in Examples 1 to 9 are summarized in Table 1.
Regarding the evaluation symbols in the table, if they are ◎ and ○, they can be used without any particular problem.

[Table 1]

(1) 75-degree specular gloss 75-degree specular gloss was measured using a specular gloss meter (GM-26D, manufactured by Murakami Color Research Laboratory) according to JIS P8142. (2) Inkjet recording test The recording test was performed using an inkjet printer (PM-750).
C, manufactured by Seiko Epson Corporation), and a predetermined solid and image pattern were recorded and evaluated according to the following criteria.

A: Recording Density The recording density of a solid pattern using black ink was measured using a Macbeth densitometer (RD915, manufactured by Macbeth). b: Image light fastness Light fastness tester (Xenon Weather Meter SC700-
(WN, manufactured by Suga Test Instruments Co., Ltd.), the recording density of the magenta ink after the treatment was measured for 25 hours, and the remaining recording density before the treatment was evaluated according to the following criteria. A: Recording density residual rate of 90% or more. ：: Recording density residual rate of 70% or more and less than 90%. Δ: Recording density residual rate of 50% or more and less than 70%. ×: Residual recording density rate of less than 50%.

C: Ink Absorption A pattern in which solid images of magenta and green (mixed color of cyan and yellow) were printed adjacent to each other, and bleeding (bleed) at the boundary was visually evaluated based on the following criteria. Since the border between the magenta and the green becomes black, it can be strictly evaluated. A: No bleeding was observed at the boundary. ：: Almost no bleeding was observed at the boundary. Δ: Bleeding was slightly observed at the boundary. X: Bleeding is remarkably observed at the boundary.

D: Water resistance of the image After the recorded matter was naturally dried for one day, it was immersed in tap water adjusted to 20 ° C. for 5 minutes and dried naturally again, and the change of the image thereafter was visually observed according to the following criteria. Was evaluated by. ◎: No image change is observed. ：: Image change is slightly observed. ：: Image change is observed. X: Most of the image flows.

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yoshihiro Kuroyama 1-30-6 Kamiochiai, Shinjuku-ku, Tokyo Nippon Paper Industries Co., Ltd. Product Development Laboratory (56) References JP-A-10-279867 (JP, A) JP 2000-168226 (JP, A) JP 2000-37947 (JP, A) JP 4-201594 (JP, A) JP 7-32725 (JP, A) JP 2-274587 (JP, A A) JP-A-7-68921 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B41M 5/00

Claims (5)

(57) [Claims] An anionic colloidal silica and an average particle size of 15 to 380 are successively provided on an ink-receiving support.
An ink-jet recording paper comprising an intermediate layer mainly composed of fine particles of zinc oxide having a thickness of 10 nm and a fixing layer mainly composed of cationic colloidal silica and a cationic polymer electrolyte. 2. The ink jet recording paper according to claim 1, wherein the cationic colloidal silica in the fixing layer has a non-spherical shape in which particles are connected. 3. The fixing layer surface has a 75 ° specular gloss of 30%.
The inkjet recording paper according to claim 1 or 2, which is as described above. 4. The coating amount of the fixing layer is 1 to 6 g / m2 in solid content.
^The inkjet recording paper according to any one of claims 1 to 3, which is within the range of ( ² ). 5. The support according to claim 1, wherein the support of the ink receiving layer is a support having an ink receiving layer containing at least a pigment and a binder as main components on a base paper. Inkjet recording paper.