JPS6049990A - Ink jet recording paper - Google Patents

Abstract

PURPOSE:To enhance water resistance of images, by a method wherein a water- base ink containing a water-soluble direct dye or the like is used for a recording material provided with a polyalkylene polyamine dicyandiamide ammonium salt condensate at least on a surface thereof. CONSTITUTION:An aqueous solution of a polyalkylene polyamine dicyandiamide ammonium salt condensate is applied to a base paper by a size press, a roll coater, an other-type coater or the like to produce an ink jet recording sheet. Ink jet recording is conducted on the recording sheet by using a water-base ink containing a direct dye or an acid dye having an anionic free radical. By this, the dye contained in the ink and a cationic resin contained in the sheet are coupled with each other, whereby the dye is prevented from being eluted, and fastness stability against sun light enhanced. The content of the cationic condensate in the recording sheet is ordinarily 0.1-4g/m<2>.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a recording sheet written using ink, and in particular, the images and characters recorded on the sheet have a high density, a clear color tone, and a fast ink absorption speed. The present invention relates to an inkjet recording sheet suitable for multicolor recording, which is fast and has improved weather resistance.

In recent years, the inkjet recording method is characterized by high speed, low noise, easy multi-color printing, great flexibility in recording patterns, and no need for development or fixing, and is suitable for hard copies of various figures including kanji and color images. It is rapidly becoming popular in various applications including equipment. Furthermore, the images formed by the multicolor inkjet method are comparable to those produced by normal multicolor printing, and when the number of copies to be produced is small, the multicolor inkjet recording method is cheaper than the normal plate making method. Attempts are being made to apply it to the fields of printing and color photographic printing.

The so-called baryta paper, which is used as a base for high-quality paper and coated paper used for general printing and photographic paper, has extremely poor ink absorption, so when used for inkjet recording, the ink remains on the surface for a long time. If a part of the device is touched by the operator, or if continuously ejected sheets overlap and the recording surface is rubbed, the image will be smeared with residual ink. In addition, if two to four color ink droplets overlap in the same place in high-density image areas or multicolor recording, the amount of ink may be large and there may be problems such as the ink mixing without being absorbed or flowing out. No, it's not practical.

This recording sheet can produce images with high density and clear tones, and it also absorbs ink quickly and does not run out, and does not smudge even if touched immediately after printing. At the same time, it is required to suppress the lateral diffusion of ink dots on the surface of the recording sheet and to obtain a high-resolution image without bleeding.

In order to solve these problems, several proposals have been made in the past. For example, Japanese Patent Application Laid-Open No. 52-53012 discloses an inkjet dispensing paper made by completely wetting a low-sized base paper with a paint for surface treatment. In particular, Japanese Patent Application Laid-Open No. 53-49113 discloses an inkjet recording paper in which a water-soluble polymer is completely coated on a sheet in which urea-formalin resin powder is completely entangled. In addition, JP-A-55
No. 5830 discloses an inkjet recording paper having an ink-absorbing coating layer on the surface of the support, and JP-A-55-51583 discloses an example in which non-colloidal silica powder is used as a pigment in the coating layer. Disclosed in Japanese Patent Publication No. 55-1467
No. 86 discloses an inkjet recording paper provided with a water-soluble polymer coating layer. Furthermore, JP-A-55-118
No. 29 has a layer structure of two or more layers, the outermost layer has an ink absorption of 1.5 to 5.5 mm/min, and the second layer has a total ink absorption of 5.5 to 60.0 mm/min. A method for adjusting the spread 9 of ink dots and absorption speed is disclosed.

However, the technical idea as typified by JP-A No. 52-58012 is to gain resolution by sacrificing a certain amount of ink absorbency;
The technical philosophy represented by No. 9113 is ink absorption, and although a certain degree of resolution can be obtained, the ink penetrates deep into the G layer, making it difficult to achieve ink density.Both are multicolor inkjet. It is unsatisfactory as a recording paper.

Therefore, as a method to improve these drawbacks, inkjet recording paper completely coated with non-colloidal silica powder was developed in Japanese Patent Application Laid-open No. 1983 (1983).
-51583, and Japanese Patent Publication No. 53-7') O discloses an optically readable barcode printing paper coated with finely powdered silicic acid.

By providing synthetic silica or other white fine powder on the surface of the layer, resolution, color properties, color density, absorption, roundness, etc. can be greatly improved, but it is not applicable to these recording media. Many inks are water-soluble, so if the image formed on the recording medium is exposed to water, it will dissolve again, and it is assumed that the image will not be stored when it is exposed to the outside air like a poster. It was still unsatisfactory for photographic applications.

Several proposals have been made to solve all of these problems. For example, Japanese Patent Application Laid-Open No. 55-53591 discloses a recording paper in which a water-soluble metal salt is applied to the surface on which recording is performed.

Furthermore, JP-A No. 56-84992 discloses an Infusiera recording method that prints on a recording medium containing a polycationic polymer electrolyte on its surface with a water-based ink containing a water-soluble direct dye or an acid dye. has been done. Further, JP-A No. 55-150396 discloses a method for making ink-jet recording water resistant by applying a water-resistance agent that forms a lake with the dye in the aqueous ink after ink-jet recording using an aqueous ink. discloses a method for making an inkjet recording sheet waterproof, in which a water-based ink is used to perform inkjet recording on an inkjet recording sheet completely coated with a water-soluble polymer, and then a waterproofing agent that makes the water-soluble polymer insolubilized is applied thereto.

However, in the methods of using various cationic resins to make images made with water-based inks water-resistant, dyes such as dicyandiamide-formalin condensate, polyamines, polyethyleneimine, and other dyes and mordants were used, but these mordants do not have sufficient water resistance. It has been found that if a satisfactory amount is used, the white paper will yellow in the air or when exposed to sunlight, and even if the white paper does not yellow, it will reduce the sunlight fastness of the dye in the recorded image. It was difficult and rare to achieve both durability (yellowing and light resistance).

In order to obtain an inkjet recording paper with improved water resistance and sunlight fastness of water-based ink images, the inventors of the present invention conducted intensive research on water-resistant agents, and as a result, they decided to improve water resistance and sunlight fastness at the same time. This was successful and led to the present invention.

That is, in an inkjet recording method in which a recorded image is obtained by jetting an aqueous inkjet ink onto an image-receiving sheet, the present inventors have proposed that the image-receiving sheet has a polyalkylene polyamine dicyandiamide ammonium salt condensate functionalized at least on its surface. It was discovered that a water-soluble dye can form a multicolor recorded image with excellent water resistance and sunlight fastness.

According to the present invention, when inkjet recording is performed on an inkjet recording sheet containing the polyalkylene polyamine dicyandiamide ammonium salt condensate with an aqueous ink containing a direct dye or an acid dye having an anionic dissociation group, the dye in the aqueous ink and the cationic resin in the recording sheet, preventing dye elution and providing good sunlight fastness.

The content of the cationic condensate is usually 0.1 to 4 mm,
Preferably, by using 0.2 to 2,000 μl, the water resistance and weather resistance according to the present invention can be improved. To apply these to recording materials, make them into an aqueous solution, mix with commonly used binders, such as oxidized starch, polyvinyl alcohol, CMC1 and other water-soluble cellulose derivatives, if necessary, and apply using a size press or roll coater. -1 Coated paper is coated onto base paper using other types of coaters, and a pigment with high ink absorption capacity, such as synthetic silica, synthetic alumina, or calcium carbonate, is used as the pigment, and a binder is added to form a coating layer. For narrow surface processing, apply the entire aqueous solution using an air knife coater, roll coater, blade coater, Suffu V-, etc.
It is possible to obtain a recording medium containing at least a cationic resin by directly adding 6 thorns into a coating liquid consisting of the above-mentioned pigment and admixture to form a complete coating layer.

On the other hand, the water-based ink used in the present invention contains at least one of a water-soluble fugitive dye and a water-soluble direct dye as a dye, and also contains a wetting agent, a dye solubilizer, a preservative,
Contains anti-piping agent, etc.

Water-soluble direct dyes include C, I direct black,
C, I direct yellow, C0 ■ direct blue,
Examples of water-soluble acid dyes include C1■Direct Red, C,I Acid Black, C0■Acid Yellow, C0■Acid Blue, C1■Acid Red,
C, I acid black, etc. are used, but of course the material is not limited to these.

Such dyes have 18o3Na, -805 in the dye molecule.
I (and which have water solubility due to -NH2 groups, etc.), such ink is attached to the surface of the recording medium,
When absorbed, the anionic group of the dye in the ink and the cationic condensate contained in the recording medium form an ionic bond to form a water-insoluble salt, improving the water resistance of the image. No reduction in sunlight fastness.

The present invention will be described below with reference to examples, but it is not limited to these examples. In addition, parts and 饅 shown in Examples refer to parts by weight and percentages by weight.

Methods for measuring various physical property values in Examples are shown below.

(1) Water resistance The image obtained by printing with cyan (C), magenta (M), yellow (Y), and black (Bt) inks is air-dried for 1 hour, then immersed in 30°C water for 3 minutes. The image density before and after dipping was measured using a Macbeth densitometer RD514, and the density after dipping was divided by the concentration of the dipping agent, which was used as a measure of the percentage total water resistance. The higher the value, the better the water resistance.

(2) Lightfastness Image 1 obtained by solid printing with cXM and yX Bt inks
Liao, xenon fade meter (manufactured by Suga Test Instruments)
FAL-25X-HCL type) at 40℃, 60 animals, illuminance 6
3W/n? The color density of the pre-irradiated product was measured using a Macbeth densitometer RD514, and the ambiguity after irradiation was divided by the density before irradiation, which was used as a measure of percentage total lightfastness. The higher the value, the better the light resistance.

(3) Blank yellowing recording paper was left in a room at 20°C and 65% RI for one month, and the degree of yellowing on the recording surface was visually judged. ○...Almost no discoloration.

Example 1 LBKP 80 parts at reactor water level 350-, N at door water level 400-
Light calcium carbonate (calcium carbonate PC manufactured by Shiroishi Kogyo Co., Ltd.) 2 as a filler to a pulp slurry consisting of 20 parts of BKP
All 5 parts were added, and 1 part of cationized diluted flour (CatoF manufactured by Tamako National Co., Ltd.) was added as a retention improver and paper direction agent, and a base paper with a basis weight of 60 V/silver was made using a Fourdrinier paper machine and size press. Oxidized starch with equipment (M83800 manufactured by Nihon Shokuhin Co., Ltd.)
4% and polyalkylene polyamine dicyandiamide ammonium salt condensate (Neofix RP manufactured by NICCA Chemical Co., Ltd.)
The recording paper of Example 1 was formed by adding a layer of 3.2 fβ with a size press 'e and h solids of -70Y) of 1%, and drying the sheet.

In addition, for comparison, the combination of Example 1 was used with polyethyleneimine (Epomin P100O, Nippon Shokubai Kagaku S) and dianediamide formalin condensate (Sunfix 70,
All of the sheets were manufactured in the same manner as in Example 1, except that the paper was replaced with the paper (manufactured by Sanyo Kasei Co., Ltd.), and were used as the recording sheets of Comparative Example 1 and Comparative Example 2, respectively, and the water resistance, light resistance, and white paper yellowing of these papers were measured. The results are shown in Table 1.

Table 1 It is clear from Table 1 that Example 1 is superior to the comparison in terms of white paper yellowing, water resistance, and light resistance.

Example 2 To a pulp slurry consisting of 90 parts of LBKP of F water 1i380d and NBKPiO parts of r Suisan 410-, 10 parts of Merck was added as a strength agent, 0.3 parts of rosin rho agent and 2.2 parts of band were added to make a pulp slurry. It is produced using a mesh paper machine, and the oxidized starch is produced using a size press machine at a solid content of 28 t/rr? Add 13 parts of polyvinylalnyl as an adhesive to a slurry consisting of 80 parts of synthetic silica, 20 parts of heavy calcium carbonate, and add antifoaming agents, flow modifiers, preservative hardening agents, etc. to the coated base paper produced by attaching pigments. Total solid content of paint with appropriate addition of 16y
/n? It was smeared with an air knife coater so that it became V-shaped, and was made into a base paper. A fabric solution consisting of polyvinyl alcohol at a concentration of 3% and the same condensate as used in Example 1 was prepared (9) and coated on the surface of the base layer with an air knife coater so that the solid content was as shown in (2). . The recording paper of Example 2 was then lightly supercalendered.

-3 (styrene-maleic acid-noalkyl ester-cation copolymer manufactured by Kindai Kagaku Kogyo), 2.

True Flock D100O (manufactured by Nippon Carbide Co., Ltd., 2゜) Tameko Recording paper of Comparative Example 3.4.5 was prepared in exactly the same manner as in Example 2. fC. Table 2 shows the results of all water resistance and weather resistance measurements of these recording papers.

From Table 2, Comparative Example 3 has insufficient water resistance, and Comparative Example 4.
It is clear that Example 2 has improved water resistance and light resistance, compared to Example 5, which has poor light resistance.

Claims (1)

[Claims] 1. In an inkjet recording method for recording on a recording medium containing a cationic resin at least on its surface using an aqueous ink containing a water-soluble direct dye and/or a water-soluble acidic dye, the cationic resin An inkjet recording paper characterized in that the resin is a polyalkylene polyamine dicyandiamide ammonium salt condensate.