JP3025773B2 - Recording sheet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a recording sheet, in particular, has excellent ink absorbency, has gloss without requiring post-printing treatment, and has a protected image surface. The present invention relates to a recording sheet that can provide a recorded matter.

[Related Art] Ink-jet printers have been rapidly spreading in recent years due to the fact that full-color printing is easy and printing noise is low. In this method, ink droplets are ejected from a nozzle toward a recording material at a high speed, and the recording material is required to quickly absorb the ink and have excellent color developing properties.

In order to satisfy such demands, it has been proposed to apply fine powdered silica or the like together with a binder on a base material, and to use a material provided with a porous layer as a recording material, and a part thereof has been put to practical use.

[Problems to be Solved by the Invention] However, these recording materials have a drawback that they have no surface gloss and that only printed matter with low surface strength can be obtained.

In order to solve such a drawback, it has been proposed to perform a lamination process after printing, but such a post-process has disadvantages in terms of labor and cost. or,
As a means for solving the problem without post-treatment, there has been proposed a sheet in which a porous surface layer is formed on a transparent support, printing is performed from the surface side, and the sheet is visible from the support side (back side) (Japanese Patent Laid-Open No.
61-197285).

However, this method has a disadvantage that the ink does not sufficiently penetrate from the printing side to the support side, and a sufficient color density cannot be obtained. Further, as a means for improving this, it has been proposed to provide an ink transport layer and an ink holding layer on a base material so as to effectively penetrate the ink (Japanese Patent Application Laid-Open No. 62-242575).

However, in this method, non-porous particles are used for the ink holding layer, and the entire holding layer is non-porous, and the ink is colored by a reaction with the non-porous layer. Is not maintained, and sufficient coloring cannot be desired.

[Means for Solving the Problems] The present inventor has eliminated the drawbacks of these conventional methods, has gloss, has a high strength on the printed surface, and has a clear image. As a result of various studies and examinations for the purpose of obtaining a sheet, a transparent substrate was used, and a porous adsorption layer for the dye and a layer for adsorbing the solvent were separately provided on the transparent substrate. It has been found that the object can be achieved by allowing the image to be visually recognized from the material side.

Thus, the present invention provides a porous layer comprising alumina hydrate and a binder of 10 to 50% by weight with respect to the alumina hydrate on a transparent substrate, and further comprising a porous layer mainly comprising finely divided silica. It is another object of the present invention to provide a recording sheet provided with a layer.

The transparent substrate used in the present invention is not particularly limited, and for example, an organic film or sheet of polyethylene terephthalate, polyester, diacetate or the like, various types of glass and the like are used.

The thickness of these substrates is selected depending on the purpose, and is not particularly limited. These substrates, if necessary for the purpose of improving the adhesion with the alumina hydrate serving as a dye-supporting medium described below,
A surface treatment such as a corona discharge treatment or a precoat layer may be provided. First, a porous layer (hereinafter referred to as alumina hydrate layer) comprising alumina hydrate and a binder in an amount of 10 to 50% by weight based on the alumina hydrate is provided on the surface of such a transparent substrate.

In such an alumina hydrate layer, a radius of 40 to 100Å
It is preferable that the total volume of the pores having the following is not less than 0.1 cc / g and less than 0.4 cc / g. When the physical properties are less than the above-mentioned range, the absorption of the dye becomes insufficient, and when the physical properties are more than the above-mentioned range, the transparency is impaired and whitish color may be formed. In addition to the above physical properties, it is preferable that the alumina hydrate layer has a total volume of pores having a radius of 100 to 1000 ° of 0.1 cc / g or less because a clearer image can be obtained. And a radius of 10-40 to add more
It is particularly preferable that the total volume of the pores having a diameter of less than Å is 0.2 to 1.0 cc / g, since an even clearer image can be obtained. The measurement of the pore size distribution in the present invention was performed by a nitrogen adsorption / desorption method using Omnisorp 100 manufactured by Omicron Technology Co., Ltd. The thickness of the alumina hydrate layer is strictly determined by the amount of ink used for printing and the like, but it is generally appropriate to employ about 1 to 20 μm.
When the thickness is less than the above range, the coloring becomes insufficient, and when the thickness exceeds the above range, the mechanical strength of the layer may be reduced or the transparency may be impaired. A variety of alumina hydrates can be employed, and in particular, pseudo-boehmite is preferred because of its excellent color development. Examples of such pseudo-boehmite include “Cataloid AS-3” (trade name) which is commercially available from Catalysis Kasei Kogyo Co., Ltd. as shown in Example 1 described below.
Alumina sol containing 7% by weight in terms of Al ₂ O ₃ solid content is diluted 100 times with pure water and dropped onto a hydrophilic collodion film and dried. An alumina sol that forms an aggregate of the formed hairy bundle of alumina hydrate is most suitable. Actually, as a means for providing the alumina hydrate layer on the transparent substrate, various methods can be adopted, but a mixed slurry of alumina hydrate and a binder is prepared in advance, and this is roll-coated, air-knife-coated, A method of applying and drying on a substrate by various coaters such as a blade coater, a rod coater, and a bar coater is preferable. As the alumina hydrate, the use of a so-called alumina sol is preferable because it is easy to obtain a preferable form as the color-forming layer, but a powdery raw material can be used if desired.

As a binder, generally, starch or a modified product thereof,
Organic substances such as PVA and its modified products, SBR latex, NBR latex, hydroxycellulose and polyvinylpyrrolidone can be used.

The amount of the binder used is 10 to 50% by weight of the alumina hydrate. When the amount of the binder used is less than the above range, the mechanical strength of the alumina hydrate layer becomes insufficient. On the contrary, when the amount exceeds the above range, the absorption of the dye may be impaired. Appropriate. The porous alumina hydrate layer thus provided is dried, and a porous layer mainly composed of fine silica (hereinafter referred to as a fine silica layer) is provided on the surface thereof.

As the finely divided silica to be used, it is appropriate to employ an average particle diameter of about 1 to 50 μm and a pore volume of about 0.5 to 3.0 cc / g. When the average particle diameter and the pore volume are less than the respective ranges, the solvent absorbency of the dye becomes insufficient, and when the average particle diameter and the pore volume exceed the above range, the absorbency becomes too high, and the dye is absorbed. Either of them is not preferable because there is a risk of being carried.

The thickness of the finely divided silica layer is strictly determined by the type of ink and solvent used, the amount of ink, and the like, but it is generally appropriate to employ about 5 to 50 μm. If the thickness is less than the above range, the absorbency is insufficient and the image is blurred.If the thickness is more than the above range, the absorbency becomes too high and the dye is absorbed and carried, so that an image may not be formed. Are not preferred.

Actually, as a means for providing the finely divided silica layer on the alumina hydrate layer, the above-described means for forming the alumina hydrate layer can be substantially adopted.

Thus, in the recording sheet according to the present invention, when the ink is supplied from the fine silica layer side, only the solvent is supported on the fine silica layer, and the dye can be supported on the alumina hydrate layer below. As a result, when the printed matter is viewed from the transparent substrate side (the back side of the printing side), the transparency of the transparent substrate is maintained almost as it is, and a clear image can be seen.

The recording sheet according to the present invention can use either water-based or oil-based ink, and is particularly excellent as an ink-jet recording sheet, but is not limited thereto and is useful as various recording sheets.

[Examples] The recording sheets obtained in Examples and Comparative Examples were evaluated by the following methods.

Printing: Using a Canon full color printer FP-510, a black 1 cm × 1 cm pattern was printed.

Color density: The reflected color density on the back side of the recording surface of the sheet printed with was measured with a Sakura densitometer PDA45.

Resolution: The resolution was evaluated in four steps based on the degree of bleeding of the pattern of the printed sheet.

(Evaluation results are indicated by 順 に>○>△> × in order of higher resolution.) Parts and% in the text are parts by weight and% by weight, respectively.

Example 1 A coating solution having a solid content of about 10% consisting of 5 parts (solid content) of pseudo-boehmite sol AS-3 (manufactured by Catalyst Kasei Co., Ltd.), 1 part (solid content) of polyvinyl alcohol PVA117 (manufactured by Kuraray Co., Ltd.) and water was prepared. Then, a polyethylene terephthalate film (100 μm manufactured by Toray Industries, Inc.) was dried with a bar coater to a thickness of 5
It was applied to a thickness of μm and dried. Further, a white carbon carplex # 80 (manufactured by Shionogi & Co., Ltd.) 10
(Solid content), 1 part (solid content) of polyvinyl alcohol PVA117 (manufactured by Kuraray Co., Ltd.), and a coating solution having a solid content of about 15%, which was coated with water, was applied so that the coating amount when dried was 7 g / m ² . After drying, a recording sheet was prepared.

Example 2 A sheet was prepared in the same manner as in Example 1, except that AS-3 used in Example 1 was replaced with alumina sol AL100 (manufactured by Nissan Chemical Industries, Ltd.).

Example 3 A sheet was prepared in the same manner as in Example 1 except that pseudo-boehmite AS-1 (manufactured by Catalyst Kasei Co., Ltd.) was used instead of AS-3 used in Example 1.

Comparative Example 1 AS-3 used in Example 1 was replaced with silica sol, Cataloid SI
A sheet was prepared in the same manner as in Example 1 except that -40 (manufactured by Catalyst Kasei Co., Ltd.) was used.

Comparative Example 2 A sheet was prepared in the same manner as in Example 1 except that Carplex # 80 used in Example 1 was replaced with calcium carbonate (average particle diameter: 0.6 μm).

Continuation of the front page (56) References JP-A-2-276671 (JP, A) JP-A-2-139275 (JP, A) JP-A-3-67684 (JP, A) JP-A-61-135785 (JP) JP-A-2-276670 (JP, A) JP-A-62-264987 (JP, A) JP-A-58-136481 (JP, A) JP-A-58-136480 (JP, A) 59-3020 (JP, A) JP-A-59-78925 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B41M 5/00

Claims (1)

(57) [Claims] A porous layer comprising alumina hydrate and a binder in an amount of 10 to 50% by weight based on alumina hydrate is provided on a transparent substrate, and a porous layer mainly comprising finely divided silica is further provided thereon. A recording sheet provided with a material layer.