JPH06155892A - Ink-jet recording paper having intense gloss - Google Patents

Abstract

(57) [Summary] [Object] The object of the present invention is excellent in ink jet recording suitability (ink absorption and color development) as a jet recording paper, and a visual image of an image after ink jet recording.
This is where the luster is given a strong luster that can be especially raised. [Structure] The ink jet recording paper having strong gloss according to the present invention has a surface gloss of JIS P-8142 as a support.
Form a film containing 80% or more of cast-coal paper containing polyvinyl alcohol with a saponification degree of 50-90 mol% and crosslinking agent of 5-50 wt% with respect to polyvinyl alcohol (solid content). It was done.

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 having strong gloss, and more specifically, to a recording sheet having strong gloss used in an ink jet recording system, the surface of the recording sheet is water-soluble. The present invention relates to an ink jet recording paper having the above-mentioned strong gloss, which is formed with a film containing a polymer compound and a crosslinking agent thereof.

[0002]

2. Description of the Related Art As is well known, ink jet recording is a so-called non-impact recording method in which the printing method does not directly touch the recording nozzle and the ink jet recording paper (hereinafter referred to as jet recording paper). From
As the jet recording paper used in such a recording method, generally available paper having a low gloss (15% or less), such as general high-quality paper and medium-quality paper, is commonly used. For this reason, this type of jet recording paper is mainly concerned with the quality of ink absorption that is compatible with the above-mentioned method, and in reality, little improvement has been made in surface quality, especially in improvement of glossiness. Met. This means that the gloss of the applied paper is set to 15% or more through a super calender, for example, to make the paper surface extremely dense and smooth at the same time to prevent ink absorption. This is because the recording property of the paper is deteriorated, and in fact, this application paper (jet recording paper)
In order to improve the surface glossiness and smoothness in the production of, the resulting paper is subjected to a super calender or gloss calender treatment. Since it passes between the nip of the roll, it is given a strong compressive action to impart strong gloss and smoothness, and although it is one means of improving the surface property of the applied paper, it also improves the ink absorbability. However, it was not practical in this respect. In recent years, however, the jet recording paper, which is comparable to photographic printing paper, has appeared due to the increasing demand for dramatically improving the visual image quality of image quality after printing by the ink jet recording method, especially multicolor printing. However, it has become clear that the low-gloss papers that have been commonly used in the past could not satisfy the above-mentioned desired requirements.

[0003]

SUMMARY OF THE INVENTION In view of the above demands, the present invention provides a super calender treatment to a conventionally used jet recording paper (general high-quality paper having a low glossiness) so as to give a strong gloss as much as possible. When recording an ink jet on the surface of a jet recording paper or an art paper or coating paper having various strong gloss that is commercially available, the former (actively imparting high gloss to low gloss paper However, as the glossiness increases, the ability to absorb water-based ink deteriorates, and the above requirements are not satisfied, and in the latter case (commercial high-gloss paper), for example, a cast coated sheet is used. When paper is used, the absorption of the water-based ink is extremely good due to its characteristics, but on the other hand, the printing gloss is lowered, so that the above requirement was not satisfied as in the former case. Therefore, the problem to be solved by the present invention is to solve the above-mentioned drawbacks rationally and effectively and to be excellent in ink jet recording suitability (ink absorption and color development) as a jet recording paper. It is intended to have a strong luster that can particularly enhance the visual image of the image.

[0004]

SUMMARY OF THE INVENTION Here, the inventor of the present invention effectively solves the problem to be solved and improves the suitability for ink jet recording and a visual image after ink jet recording.
From the viewpoint that it is indispensable to simultaneously have the contradictory characteristics that the surface gloss of the jet recording paper to be applied must be very high and the ink absorption must be good in order to raise the image quality. As a result of earnestly advancing research based on the above, a sheet (recording paper) having a strong gloss used for an ink jet recording method (non-impact recording method), that is, a surface glossiness of 80 as JIS P-8142 as a support. %
By forming a film containing a water-soluble polymer compound and its cross-linking agent on the above cast coated paper, it was confirmed that a jet recording paper with good gloss and texture as strong glossy paper was obtained. It has been found that when the ink jet recording is performed by the ordinary method, the ink jet recording is excellent in properness, and the visual image of the image after recording can be greatly enhanced, and the problems to be solved can be solved at once. did it. That is, according to the present invention, the surface of the support is a cast coat having a surface gloss of 80% or more according to JIS P-8142.
Polyvinyl alcohol with a saponification degree of 50 to 90 mol% and polyvinyl alcohol (solid content conversion) 5 to
The ink jet recording paper has a strong gloss and has a film containing 50% by weight of a crosslinking agent.

As the water-soluble polymer compound used here, polyvinyl alcohol, polyacrylamide, polyvinylpyrrolidone, poloethylene oxide and various starch derivatives can be considered. According to the experiments of the present inventor, polyvinyl alcohol Compared with the case of using the above-mentioned other water-soluble compounds, the use of the resin has a far superior film-forming property and is effective in imparting strong gloss to the film surface. It is the best. In practical use of the polyvinyl alcohol, the polyvinyl alcohol is saponified by a conventional method, but it is important that the saponification degree is 50 to 90 mol% and the saponification degree is less than 50 mol%, or When the content is 90 mol% or more, the hydrophilicity of polyvinyl alcohol deteriorates, so that when a film containing this is formed on the surface of the recording sheet, the film cannot exhibit the desired ink absorbing ability. It is not suitable for practical use. Therefore, it is satisfied by applying a coating solution prepared by mixing the polyvinyl alcohol having a saponification degree of 50 to 90 mol% prepared as described above with an organic solvent to the surface of the recording sheet by a conventional method.

As the crosslinking agent used in the present invention, a copolymer of olefin or styrene having 2 to 4 carbon atoms such as glyoxal, epoxy resin, urea formaldehyde resin and maleic anhydride, or ammonium thereof. The use of one or two or more selected from salts or sodium salts is preferable, but isoban (trade name, manufactured by Kuraray Isoprene Chemical Co.), which is a copolymer of isobutylene and maleic anhydride, is used. Is optimum, and the amount thereof is 5 to 50% by weight (in terms of solid content) of polyvinyl alcohol, preferably 10 to 30% by weight. If the amount used is less than 5% by weight, the desired water resistance of the film cannot be obtained, and if it exceeds 50% by weight, the desired effect cannot be obtained due to deterioration of the ink absorption capacity of the film.

In the above, the polyvinyl alcohol and the cross-linking agent are mixed with the polyvinyl alcohol previously prepared to have a saponification degree of 50 to 90 mol% with respect to polyvinyl alcohol (solid content) 5 to. If 50% by weight is added and mixed with stirring with an organic solvent, a desired coating liquid can be easily obtained (see Examples). In this case, for the purpose of improving the coatability of the coating liquid including the coating liquid of the present invention and improving the quality and characteristics of the recording sheet after coating on the sheet substrate, methanol, ethanol, Organic solvents such as isopropyl alcohol, methylocerosolve, ethyl acetate, etc., or surfactants, auxiliary agents such as modified sodium polyacrylate, etc., and adsorbent pigments such as silica, calcium silicate, etc. within the range that does not impair glossiness. Can also be mixed.

The coating solution thus obtained is applied onto the surface of a recording sheet having strong gloss by a conventional method, and the coating amount is 1 g / m ^{2 to} 20 g / m ² (solid content conversion: the same) preferably ^{1g / m 2 ~10g / m 2} . If this coating amount is 1 g / m ² or less, when jet recording is performed on the sheet surface after coating, the presence of an excessive amount of ink that exceeds the ink absorption capacity at the printing area with a large amount of ink leads to complete fixing. Since it takes a long time, it is easy for ink to flow during this time, and continuous images with clear ink droplets cannot be obtained.
When it is more than m ² , not only does the drying become poor, but it is economically impractical. The coating of the coating liquid on the sheet substrate is carried out by a known air knife coater, bar coater, doctor coater, roll coater or a combination thereof. Be satisfied with. The recording sheet used in the present invention is a cast coated paper or a strong gloss paper obtained by using the manufacturing process of the cast coated paper.

However, as is well known, the above-mentioned commercially available cast-coated paper is mainly used for high-grade offset printing by using a cast drum having a mirror-finished surface and a special paint, which makes it difficult to obtain a mirror-finished gloss which is difficult to obtain by a normal calendering process. Therefore, when such a commercially available product is used as it is for ink jet recording of the present invention, the coloring of the ink dye adhering to the paper surface is so-called dull, and the degree of dullness is particularly large, so that it is preferable. Not only the color tone is not obtained, but also the tendency of lowering the surface gloss at the printed portion is recognized, and thus a jet recording which can obtain a beautiful printing effect with a high visual image comparable to the photographic printing paper intended in the present invention can be obtained. It should be understood that it is not suitable for paper. Therefore, as is clear from the above, the essential requirements to be especially noted in the present invention, the jet recording paper applied to the ink jet recording system has a surface glossiness of 80% or more according to JIS P-8142. When the glossiness is less than 80%, the ink jet recording property is good, but in terms of the visual image of the recorded image, the glossiness is good.
It is inferior to the case of 80% or more, so that a recorded image having an aesthetic appearance comparable to that of the photographic printing paper desired in the present invention cannot be obtained, and the use of this kind of glossy paper is not suitable.

[0010]

The present invention is capable of fully exerting the following unique effects that have not been heretofore achieved, and therefore, this has a great effect on the related industrial fields. (1) The surface gloss of the support is 80 according to JIS P-8142.
% Or more of the cast coated paper, polyvinyl alcohol having a saponification degree of 50 to 90 mol% and polyvinyl alcohol against polyvinyl alcohol.
Since it is an ink jet recording paper having a strong gloss with a film containing 5 to 50% by weight of a cross-linking agent (in terms of solid content), the obtained sheet has good gloss and texture as a high gloss paper, Moreover, it is possible to obtain a desired jet recording paper excellent in ink jet recording suitability (ink absorbability, color developability). (2) Therefore, when this jet recording paper is applied to an ink jet recording system and recording is performed on the paper surface by a conventional method, the visual image of the image after recording is dramatically enhanced and aesthetic elements are simultaneously provided. The obtained image can be obtained, and an image similar to that seen in a color photograph can be obtained. (3) Further, as described above, the present invention can be applied to the ink jet recording system to exert the above-mentioned effects, so that the ink jet recording apparatus used in this system can have high resolution and high gradation. Together, the visual image of the image after ink jet recording can be further enhanced.

[0011]

EXAMPLES The present invention will be described in more detail below with reference to examples (including comparative examples). Comparative Examples 1 to 4 include the case of the following (1), Examples 1 to 4 include the cases of the following (2) and (3), and the results are visually observed for color density, image quality, and ink. The results are shown in Tables 1 and 2 which are evaluated according to the drying property and the visual image. (1) Degree of saponification 78 to 81 mol% polyvinyl alcohol (PVA-420 (trade name), manufactured by Kuraray Co., Ltd.) 7% by weight Methyl alcohol 30% by weight was mixed by a conventional method, and the obtained coating liquid was obtained. Commercially available cast coated paper (Mariest (trade name), via a bar coater,
Hokuetsu Paper Mills) 80-88% gloss, 210 g / m ² -250 tsubo
g / m ² or commercially available cast coat paper (Miracoat K-Gold (trade name), manufactured by Kanzaki Paper Co., Ltd.) Gloss 83%, tsubo 8
A jet recording paper is obtained by applying 4.9 g / m ^{2 so} that the coating amount after drying is 5 g / m ² or 4 g / m ² .

(2) Saponification degree 71.5 to 75 mol% polyvinyl alcohol (KP-08 (trade name) manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) 6% by weight isobutylene, maleic anhydride copolymer: isoban-104 (trade name) (Manufactured by Kuraray Isoprene Chemical Co., Ltd.) 1.5 wt% isopropyl alcohol 30 wt% were mixed by a conventional method, and the obtained coating solution was put on a commercial cast coat paper (Mariest) via a bar coater. Gloss 80 ~
88%, tsubo 210 g / m ² to 250 g / m ² coating amount after drying
A jet recording paper is obtained by coating so as to be 3 g / m ² .

(3) The coating solution obtained under the same conditions as in the above (2) was put on a commercial cast coated paper (Miracoat K-Gold (trade name)) through a bar coater. , Kanzaki manufactured paper Co.) gloss 83%, the coating amount after drying basis weight 84.9 g / m ² to obtain a jet recording paper was coated to a 4g / m ^2.

[0014]

[Table 1]

[Table 2]

Comparative Examples 5 to 8 are the following (1) ', (2)',
The case (3) ′ was included, and the results were evaluated in the same manner as in the above-mentioned Examples and are shown in Table 3. (1) 'Commercially available cast coated paper (Mariest, manufactured by Hokuetsu Paper Mills), glossiness 88%, tsubo 210 g / m ² commercially available coated paper (SK-coat (trade name), Sanyo Kokusaku) Gloss 60%, tsubo 84.9 g / m ^{2 A} commercial product itself is used as a jet recording paper without applying the required coating liquid (see paragraphs (1) to (3) of the comparative example) on both surfaces.

(2) 'Commercially available coated paper (Perfect W)
(Product name), Hokuetsu Paper Mills) 48% gloss, 190 g / tsubo
A jet recording paper is prepared by applying a coating solution similar to the item (2) of the comparative example to m ² under the same conditions.

(3) 'Commercially available cast coated paper (Mariest, manufactured by Hokuetsu Paper Mills) has a gloss of 88%, a weight of 210 g / m ² , and a saponification degree of 98 to 99 mol% polyvinyl alcohol (PVA-117 ( (Trade name), manufactured by Kuraray Co., Ltd.) 4% by weight cross-linking agent (Isoban-104) 1% by weight Methyl alcohol 20% by weight A coating solution after drying through a bar coater has a coating amount of
And coated to a 3 g / m ² and jet recording paper.

[0018]

[Table 3]

The above jet recording paper (including (1) to (3))
The items (1) ′ to (3) ′) were evaluated under the same conditions through an ink jet recording device (image printer IO-700 (trade name), manufactured by Sharp Corporation). It depends on whether the image was recorded or not (visual observation). Evaluation criteria As follows. (B) Color density and image quality: -At the time when 24 hours have passed after recording, the color density and the image quality are good, and the color density and the image quality are slightly deteriorated. The color density and the image quality are deteriorated. If x is markedly recognized, it is marked with x. (B) Dryability of ink: − By pressing a high-quality paper on the recording part (printing part) to transfer the unfixed ink to the high-quality paper, the part where the ink is not transferred is completely fixed, and within 3 minutes at the mixed-color print part. When the fixing is completed in ⊚, when the fixing is completed within 10 minutes in the mixed color printing area, ■ is indicated in Δ, when the fixing is completed within 30 minutes in the mixed color printing area, and in 30 minutes at the mixed color printing area Those that require the above are marked with x. (C) Luminous image: -Once evaluated as excellent by comprehensive judgment considering aesthetic image of recorded image, ○ is evaluated as inferior. . The surface glossiness of the jet recording paper was measured with a GM-26D type gloss meter (manufactured by Murakami Color Research Laboratory). Examples 1 to 3 are comparative examples 1 to 3.
In comparison with Comparative Example 4, although the coating amount on the support was small, the glossiness was improved. In Example 4 as well, although the coating amount was the same as in Comparative Example 4, the glossiness was improved. It was seen.

Claims (2)

[Claims] 1. A support having a surface gloss of JIS P-81.
42, 80% or more of cast coated paper, saponification degree of 50 ~
An ink jet recording paper having a strong gloss, which is characterized in that a film containing 90 mol% of polyvinyl alcohol and 5 to 50 wt% of polyvinyl alcohol (based on solid content) of a crosslinking agent is formed. 2. The cross-linking agent is one or more selected from olefins having 2 to 4 carbon atoms or a copolymer of styrene and maleic anhydride, or an ammonium salt or sodium salt thereof. An ink jet recording paper having a strong gloss according to 1.