JP5200089B2 - Inkjet recording material and electric signboard using the same - Google Patents

Description

  The present invention relates to a recording material for an ink jet printer, and to a material suitably used for an electric signboard.

  In recent years, the development of inkjet recording technology has been remarkable, and many models from monochrome to full color have been put on the market. It has come to be used for the production of a so-called display board.

  On the other hand, many display boards are installed on wall surfaces of underpasses, train platforms, etc., for product advertisements of various companies and various information transmission. Among them, there is an electric signboard in which a rear light source such as a fluorescent lamp, a transmissive display board, an acrylic board, and the like are arranged inside a rectangular box. In such a case, characters, figures, and the like applied to the transmissive display board are recognized as a transmissive image by light emission from the back light source. In recent years, an ink jet recording material has been used as the transmission display plate.

  Since such an electric signboard mainly observes a transmission image, it is desired that an ink jet recording material used as a transmission display board has a good image density of the transmission image.

  Therefore, in order to improve the image density of the transmission image, means for adding a relatively large amount of pigment to the ink receiving layer of the ink jet recording material is employed.

  However, when a relatively large amount of pigment is added to the ink receiving layer, the image density of the transmitted image is improved, but fine print omissions occur in some parts of the image. This fine print omission is not so problematic when observing the reflected image, but if the transmission image is observed by emitting light from the back light source, light leaks from the print omission part and the appearance of the transmission image is reduced. There was a problem.

  Therefore, as a result of pursuing the above problems, the present inventor has found that the cause of fine print omission is a fine crack generated in the ink receiving layer. As a result of further research, such cracks occur when only pigments having a general shape such as an irregular shape are used as pigments to be contained in the ink receiving layer. It has been found that cracks generated in the ink receiving layer can be reduced by including a pigment, and this has been solved.

That is, the ink jet recording material for an electric signboard of the present invention contains a binder resin and a pigment in the ink receiving layer, and contains 50 to 200 parts by weight of the pigment with respect to 100 parts by weight of the binder resin. Among the pigments, 20 to 80 parts by weight are needle-like pigments having a major axis of 2.5 μm or more .

Preferably, the long diameter of the acicular pigment is 5.0 μm or more.

  The ink jet recording material of the present invention is preferably characterized in that the ink receiving layer is formed on a support and the ink receiving layer is located on the outermost surface. Moreover, the electric signboard of the present invention uses the inkjet recording material for electric signboards of the present invention as the transmissive display board in the electric signboard having a back light source, a transmissive display board, and an acrylic board in order inside the box. It is characterized by this.

  The ink jet recording material of the present invention is characterized in that the ink receiving layer contains needle-like and / or plate-like pigments. Therefore, cracks in the ink receiving layer are reduced, and fine print omissions are prevented from occurring in the image, and the appearance of the transmitted image can be improved while having a sufficient image density.

  The ink jet recording material of the present invention contains a pigment in the ink receiving layer, and includes an acicular and / or plate shaped pigment as the pigment. Hereinafter, embodiments of each component will be described.

  The ink receiving layer can be classified into those that can be handled by the ink receiving layer alone, such as those obtained by forming a resin having an ink receiving property, and those that are difficult to handle by the ink receiving layer alone. When it is difficult to handle the ink receiving layer alone, the ink receiving layer is formed on the support. The support can be used without particular limitation as long as it has optical transparency, but plastic films such as polyester, polycarbonate, polyvinyl chloride, polyethylene, polypropylene, and polystyrene are preferably used. Although the thickness of a support body is not specifically limited, From points, such as the conveyance property to an inkjet printer, the thing of 5-300 micrometers is used suitably.

  The ink receiving layer is composed of at least a binder resin and a pigment.

  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 water-soluble or hydrophilic resins include natural resins such as albumin, gelatin, casein, starch, arabic gum, sodium alginate, carboxymethyl cellulose, hydroxyethyl cellulose, polyamide, polyacrylamide, polyphenylacetoacetal, polyvinyl acetal, polyvinyl formal. , Synthetic resins such as polyethyleneimine, polyvinylpyrrolidone, melamine resin, polyurethane, polyvinyl alcohol, polyester, poly (meth) acrylic acid soda, (meth) acrylic acid ester copolymer, and these may be used alone or in combination of two or more. Can be used as a mixture.

  The thickness of the ink receiving layer is preferably 5 to 70 μm when the ink receiving layer is provided on the support. When the thickness is 5 μm or more, ink absorbability can be improved, and when the thickness is 70 μm or less, curling can be prevented. When the ink receiving layer is handled alone without a support, the thickness of the ink receiving layer is preferably 5 to 300 μm in consideration of transportability and handling properties to an ink jet printer.

  The pigment is added mainly for improving the image density of the transmission image.

  The shape of the pigment is generally indefinite or spherical, but the present invention is characterized in that the pigment in the ink receiving layer contains a needle-like and / or plate-like pigment. Both needle-like pigments and plate-like pigments can reduce cracks in the ink-receiving layer, but needle-like pigments are preferred because they are more effective in reducing cracks. The needle-like or plate-like pigment has a major axis of 2.5 μm or more, preferably 5.0 μm or more. By setting the major axis to 2.5 μm or more, the ink receiving layer can be effectively prevented from cracking.

  The added amount of the pigment is 50 to 200 parts by weight, preferably 70 to 150 parts by weight with respect to 100 parts by weight of the binder resin of the ink receiving layer. By setting it to 50 parts by weight or more, the image density of the transmission image can be made sufficient, and by making it 200 parts by weight or less, the coating strength of the ink receiving layer can be made sufficient. Here, out of 50 to 200 parts by weight of the pigment, it is desirable that a total of 10 to 100 parts by weight, preferably 20 to 80 parts by weight, of the needle-like and / or plate-like pigments are contained. By setting it to 10 parts by weight or more, it is possible to effectively prevent cracking of the ink receiving layer, and by setting it to 100 parts by weight or less, needle-like and / or plate-like pigments protrude from the ink receiving layer. It is possible to prevent image defects due to the above.

  The above-mentioned pigments are inorganic such as silica, clay, talc, calcium carbonate, calcium sulfate, barium sulfate, aluminum silicate, titanium oxide, synthetic zeolite, alumina, smectite, regardless of amorphous, spherical, needle-like, or plate-like. In addition to pigments, there are organic pigments such as resin beads made of styrene resin, urethane resin, benzoguanamine resin, silicone resin, acrylic resin, or hollow resin beads made of these as raw materials. These may be used alone or in combination of two or more. Can be used. In addition, an inorganic pigment whose surface is coated with a conductive agent can be used, and such a pigment is preferable in that a charging pattern generated during recording of an ink jet printer can be effectively prevented.

  In the ink receiving layer, additives such as a leveling agent, an ultraviolet absorber, an antioxidant, and a chelating agent may be added.

  As a method for forming the ink receiving layer, a coating liquid is prepared by dissolving or dispersing the constituents of the ink receiving layer in an appropriate solvent, and the coating liquid is roll coating, bar coating, spray coating, air knife coating. The method of apply | coating and drying on a support body by known methods, such as a method, is mention | raise | lifted.

  In order to adjust the adhesion of the ink receiving layer, an anchor coat layer is provided between the ink receiving layer and the support, or the surface of the support opposite to the ink receiving layer is used to prevent the occurrence of curling. In order to prevent the charging, a backcoat layer may be provided on the ink receiving layer or on the surface of the support opposite to the ink receiving layer.

  As described above, the ink jet recording material of the present invention is characterized in that the ink receiving layer contains needle-like and / or plate-like pigments. Therefore, cracks in the ink receiving layer are reduced, and fine print omissions are prevented from occurring in the image, and the appearance of the transmitted image can be improved while having a sufficient image density.

  The following examples further illustrate the present invention. “Parts” and “%” are based on weight unless otherwise specified.

[Example 1]
On a transparent polyester film (Lumirror T60: Toray Industries, Inc.) having a thickness of 100 μm, an ink receiving layer coating liquid having the following composition is applied by a bar coating method so that the thickness after drying is 40 μm, and dried to form an ink receiving layer. The ink jet recording material was obtained.

<Ink-receiving layer coating solution>
・ 10 parts of polyvinyl alcohol (solid content: 100%) (Gohsenol AH-17: Nippon Synthetic Chemical Industry Co., Ltd.)
・ Atypical pigment 10 parts (Silicia 740: Fuji Silysia Chemical Co., Ltd.)
-5 parts of acicular pigment (FT-3000: Ishihara Sangyo Co., Ltd., major axis 5.2 μm)
・ 225 parts of pure water

[Example 2]
An ink jet recording material was obtained in the same manner as in Example 1 except that the needle pigment of the ink receiving layer coating liquid was changed to a needle pigment (FT-2000: Ishihara Sangyo Co., Ltd., major axis 2.9 μm).

[Example 3]
An ink jet recording material was obtained in the same manner as in Example 1 except that the needle pigment of the ink receiving layer coating liquid was changed to a plate pigment (plate barium sulfate A: Sakai Chemical Industry Co., Ltd., major axis 7.5 μm). .

[Comparative example]
An ink jet recording material was obtained in the same manner as in Example 1 except that the ink-receiving layer coating liquid did not contain a needle pigment.

  For the ink jet recording materials obtained in Examples 1 to 3 and the comparative example, the ink receiving layer was evaluated for cracks. In the evaluation method, the ink jet recording material was watermarked on a fluorescent lamp, and the degree of cracking of the ink receiving layer was visually measured. As a result, “◎” indicates that no crack was generated, and “◯” indicates that the crack was slightly generated but was less than that of the comparative example. The results are shown in Table 1.

  As can be seen from the results in Table 1, the ink receiving layers in Examples 1 to 3 contain a needle-like and / or plate-like pigment in the ink receiving layer, so that the ink receiving layer cracks in comparison with the comparative example. Was reduced. In particular, Example 1 contained a needle-like pigment and had a major axis of 5.0 μm or more, so no cracks in the ink receiving layer were observed.

  On the other hand, in the comparative example, since the ink-receiving layer does not contain a needle-like and / or plate-like pigment, many cracks in the ink-receiving layer are observed.

  In addition, when an image was output to the inkjet recording materials of Examples 1 to 3 using an inkjet printer (PM-700C: Seiko Epson Corporation), the transmission image density was good and the transmission image looked good. No print omission was observed to the extent that it was reduced. Particularly, in the case of Example 1, no omission of printing was observed. On the other hand, when an image was similarly output to the inkjet recording material of the comparative example, the transmission image density was the same as that of the example, but many printing omissions were observed, and the appearance of the transmission image was reduced. It was.

Claims (4)

An ink jet recording material containing a binder resin and a pigment in an ink receiving layer, the pigment containing 50 to 200 parts by weight with respect to 100 parts by weight of the binder resin, and 20 to 80 parts by weight of the pigment having a major axis of 2 An inkjet recording material for electric signboards, characterized by being a needle-shaped pigment having a diameter of 5 μm or more . 2. The ink jet recording material for an electric signboard according to claim 1, wherein a major axis of the needle-shaped pigment is 5.0 [ mu] m or more.   The inkjet recording material for an electric signboard according to claim 1 or 2, wherein the ink receiving layer is formed on a support, and the ink receiving layer is located on the outermost surface.   In the electric signboard which has a back light source, a transmissive display board, and an acrylic board in order inside a box, the inkjet recording material for an electric signboard according to any one of claims 1 to 3 is used as the transmissive display board. A featured electric signboard.