JPH0415745B2 - - Google Patents

Description

[Detailed description of the invention]

(A) Industrial Application Field The present invention relates to a recording medium recorded using ink, and in particular, a recording medium that has high density of images and characters recorded on the medium, and has excellent absorbency and storage stability of recorded images. This invention relates to an inkjet recording medium. (B) Prior art and its problems The inkjet recording method uses various operating principles to fly minute droplets of ink and make them adhere to a recording medium such as paper, thereby recording images, characters, etc. , high speed, low noise, easy multicolor printing, great flexibility in recording patterns, and no need for development or fixing, making it suitable for a variety of uses as a recording device for various shapes and color images, including kanji. It is rapidly becoming popular. Furthermore, images formed using the multicolor inkjet method can produce records that are comparable to multicolor printing using the plate making method or printing using the color photographic method, making it ideal for applications that require fewer copies to be produced. Since it is cheaper than photographic technology, it is being widely applied to the field of full-color image recording. Efforts have been made in terms of equipment and ink composition to use high-quality paper or coated paper used for ordinary printing and writing as the recording medium used in this inkjet recording method. However, as the performance of inkjet recording devices has improved and their applications have expanded, such as higher speeds, higher definitions, and full-color inkjet recording devices, more sophisticated characteristics have come to be required of recording media. In other words, the recording medium must have high ink dot density, bright and colorful tones, ink absorption is fast and the ink will not run out or smudge even when ink dots overlap, and the ink dots must be The horizontal diffusion of the image should not be larger than necessary, and the surrounding area should be smooth and not blurry. Furthermore, it is required that the resistance of the dye when the recorded image is exposed to ultraviolet rays, oxygen in the air, or water be not reduced, but preferably increased. Several proposals have been made to solve these problems. For example, JP-A-52-
No. 53012 describes inkjet recording paper, which is made by moistening a low-size base paper with a coating for surface treatment.
Further, JP-A-53-49113 discloses an inkjet recording paper in which a sheet containing urea-formalin resin powder is impregnated with a water-soluble polymer. Although these general paper type inkjet recording papers absorb ink quickly, they have the disadvantage that the periphery of dots tends to become blurred and the dot density is low. Further, JP-A No. 55-5830 discloses an inkjet recording paper having an ink-absorbing coating layer on the surface of the support, and JP-A No. 55-51583 discloses a non-colloidal pigment as a pigment in the coating layer. An example using silica powder is disclosed in JP-A-55-11829, and an example of smear paper using a two-layer structure with different ink absorption speeds is disclosed. These coated paper-type inkjet recording papers are improved over general paper-type inkjet recording papers in terms of dot diameter, dot shape, dot density, and color tone reproducibility, but there are Many inks are water-based inks that use water-soluble dyes, and if the image formed on the recording medium is exposed to water, the dye may dissolve again and ooze out, significantly reducing the value of the recorded material. There is a problem. Therefore, in order to improve this drawback, for example, JP-A-55-53591 discloses an example in which a water-soluble metal salt is applied to the recording surface, and JP-A-56-84992 discloses a method in which a polycationic polymer electrolyte is applied. An example of a recording medium containing on the surface is disclosed in JP-A-55-150396, and a method of applying a water-resistant agent that forms a lake with the dye in the ink after inkjet recording, and JP-A-55-150396 describes No. 56-58869 discloses a method for making a recording sheet coated with a water-soluble polymer waterproof by insolubilizing the water-soluble polymer after inkjet recording. However, with these methods, the effect of water resistance may be weak, or the water resistance agent may cause some kind of reaction with the dye, reducing the shelf life of the dye, making it difficult to achieve both sufficient water resistance and light resistance. It was quite difficult. (C) Purpose of the Invention The present inventors have intensively studied methods for improving the water resistance and light resistance of inkjet recording paper on which characters and images are recorded with water-based ink using water-soluble dyes, and have developed methods for improving the water resistance and light resistance of the images. Achieved the purpose.
That is, an object of the present invention is to provide a recording paper suitable for inkjet recording that improves water resistance without reducing the light resistance of images recorded using water-soluble dyes. (D) Structure and operation of the invention In other words, the present invention provides an inkjet recording paper that obtains a recorded image by using a water-based ink containing a water-soluble dye on a recording paper made mainly of pulp fibers. This is an inkjet recording paper characterized by containing a soluble magnesium compound. The cationic resin referred to in the present invention refers to a monomer, oligomer, or polymer that dissociates and exhibits cationic properties when dissolved in water, preferably having a quaternary ammonium group, and particularly preferably one of the following () to (). A compound having a structure represented by the general formula. In the formula, R ₁ , R ₂ , R ₃ are alkyl groups, m is 1 to 7,
n represents 2 to 10, and Y represents an acid group. In the formulas () to (), R ₁ and R ₂ are −CH ₃ and −CH _2
-CH3 , _-CH2 - _CH2 -OH and Y represent acid groups. () Polyalkylene polyamine dicyandiamide ammonium salt condensate Examples of the compound represented by the general formula () include Nalpoly 607 (manufactured by Nalco Chemical Co., Ltd.) and Polyfix 601 (manufactured by Showa Kobunshi Co., Ltd.). The compounds represented by the general formulas () to () are polydiallylamine derivatives, obtained by cyclopolymerization of diallylamine compounds, and Percoll 1697
(Allied Colloid), Cat Floc (Calgon
Corp), PAS (Nitto Boseki Co., Ltd.), Neo Fixtures
Examples include RPD (manufactured by NICCA Chemical Co., Ltd.). Furthermore, examples of the compound represented by the general formula () include Neofix RP-70 (manufactured by NICCA Chemical Co., Ltd.). The content of the cationic resins represented by these general formulas () to () is usually 0.1 to 4.
g/m ² , preferably 0.2 to 2 g/m ² . The poorly soluble magnesium compound referred to in the present invention is
Magnesium oxide, magnesium hydroxide, magnesium carbonate, magnesium oxalate, magnesium silicate, magnesium hydroxide carbonate, magnesium calcium carbonate, etc. Usually have a solubility in water of 1% by weight or less, preferably 0.2% by weight or less, particularly preferably 0.05% by weight % or less of magnesium compounds. The content of these magnesium compounds is
0.01-20g/ ^m2 , preferably 0.05g/ ^m2-10g /
m ² , more preferably 0.1 g/m ² to 5 g/m ² . In the present invention, as a method for incorporating these cationic resins and sparingly soluble magnesium compounds into recording paper, when pulp fibers are disintegrated into a slurry and made into paper using a paper machine, the cationic resin and sparingly soluble magnesium compounds are added to the recording paper. At least one of them is mixed with pulp fibers to form a slurry, which is then made into a paper, or a coating liquid in which at least one of these cationic resins and poorly soluble magnesium compounds is dispersed or dissolved is applied using a size press machine. It can be included. In addition, inorganic pigments and organic pigments commonly used in paper making can be used as fillers or in a size press coating solution. Furthermore, there is no problem in using together water-soluble resins and adhesives that are normally used in size press liquids. Examples of inorganic pigments include light calcium carbonate,
Heavy calcium carbonate, kaolin (white clay), talc,
Calcium sulfate, barium sulfate, titanium oxide, zinc oxide, zinc sulfide, zinc carbonate, satin white,
White pigments and organic pigments such as aluminum silicate, diatomaceous earth, calcium silicate, synthetic silica, aluminum hydroxide, alumina, and lithopone include styrene plastic pigments, acrylic plastic pigments, microcapsules, and urea resin pigments. . Preferable examples include light or heavy calcium carbonate, talc, clay, and synthetic silica. Particularly preferred is synthetic silica, and the synthetic silica referred to here includes dry method silica produced by thermal decomposition of silicon tetrachloride, so-called white carbon such as double decomposition precipitation products of sodium silicate with acid, carbon dioxide, ammonium salt, etc. Silica sol obtained through thermal decomposition of sodium silicate with acid or through an ion-exchange resin layer, or colloidal silica obtained by heating and aging this silica sol. Silica gel, in which primary particles on the order of tens of millimeters and microns become three-dimensional secondary particles with siloxane bonds, as well as silica sol, sodium silicate, sodium aluminate, etc., are used as starting materials and heated at 80°C to 120°C. Refers to synthetic silicon compounds mainly composed of silicon dioxide, such as the so-called synthetic molecular sieves produced. Examples of water-soluble resins or adhesives include oxidized starch, etherified starch, cellulose derivatives such as carboxymethyl cellulose and hydroxyethyl cellulose, casein, gelatin, soy protein, polyvinyl alcohol and its derivatives, maleic anhydride resin, and ordinary styrene. - Conjugated diene polymer latex such as butadiene copolymer, methyl methacrylate-butadiene copolymer, acrylic polymer latex such as polymer or copolymer of acrylic acid ester and methacrylic acid ester, ethylene vinyl acetate copolymer Vinyl polymer latices such as, or functional group-modified polymer latices with monomers containing functional groups such as carboxyl groups of these various polymers, aqueous thermosetting synthetic resins such as melamine resins, urea resins, etc. Adhesives and synthetic resin adhesives such as polymethyl methacrylate, polyurethane resins, unsaturated polyester resins, vinyl chloride-vinyl acetate copolymers, polyvinyl butyral, and alkyd resins are used alone or in combination. Preferably, starch derivatives and/or polyvinyl alcohol and polyvinyl alcohol derivatives are used. Further, the pulp fiber is mainly composed of commonly used wood pulp, but inorganic or organic fibrous substances such as synthetic pulp, synthetic fiber, glass fiber, etc. can also be used in combination. The aqueous ink referred to in the present invention is a recording liquid comprising the following colorant, liquid medium, and other additives. As the coloring agent, water-soluble dyes such as direct dyes, acid dyes, basic dyes, reactive dyes, and food colorings are preferably used.

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【table】

[Table] In addition, water and various water-soluble organic solvents, such as methyl alcohol,
Ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol,
Alkyl alcohols having 1 to 4 carbon atoms such as sec-butyl alcohol, tert-butyl alcohol and isobutyl alcohol; Amides such as dimethylformamide and dimethylacetamide; Ketones or ketone alcohols such as acetone and diacetone alcohol; tetrahydrofuran and dioxane Ethers such as polyethylene glycol, polypropylene glycol, etc.; polyalkylene glycols such as ethylene glycol, propylene glycol, butylene glycol, triethylene glycol, 1,2,6-hexanetriol, thiodiglycol, hexylene glycol, diethylene glycol, etc. Alkylene glycols having 2 to 6 alkylene groups; examples include lower alkyl ethers of polyhydric alcohols such as glycerin, ethylene glycol methyl ether, diethylene glycol methyl (or ethyl) ether, and triethylene glycol monomethyl ether. Among these many water-soluble organic solvents, polyhydric alcohols such as diethylene glycol and lower alkyl ethers of polyhydric alcohols such as triethylene glycol monomethyl ether and triethylene glycol monoethyl ether are preferred. Examples of other additives include PH regulators, sequestrants, antifungal agents, viscosity regulators, surface tension regulators, wetting agents, surfactants, and rust preventives. Ink jet suitability was measured by the following method. Light resistance was measured using a xenon fade meter (Suga Test Instruments Co., Ltd.) for the image area obtained by solid printing with C, M, Y, and Bk inks using a Canon inkjet printer (A-1210). Manufactured by FML−
25X-HCL type) at 40℃, 60%, illuminance 41w/ ^m2
The color density before and after irradiation was measured using a Macbeth densitometer RD514, and the percentage of the color density after irradiation divided by the color density before irradiation was expressed as light resistance (residual rate). Water resistance was determined by using the same Canon inkjet printer to print solid images using C, M, Y, and Bk inks, immersing them in running water at 30°C for 3 minutes, and measuring the density before and after immersion using Macbeth density. The water resistance value was determined by dividing the concentration after immersion by the concentration before immersion. The higher the value, the better the water resistance. The ink absorption speed is measured immediately after solid red printing (magenta + yellow) (about 1 second) using a Sharp or Canon inkjet printer.
The paper was fed to the paper, and the paper was brought into contact with a paper presser roll or a finger, and judgment was made based on whether dirt appeared or not. (E) Examples The present invention will be described below with reference to Examples, but the invention is not limited to these examples. Note that parts and percentages shown in the examples mean parts by weight and percentages by weight. Example 1 70 parts of LBKP with a water content of 350 ml and a water content of 400 ml
A pulp slurry consisting of 30 parts of NBKP, 10 parts of synthetic silica (Nipseal LP manufactured by Nippon Silica Co., Ltd.), 5 parts of magnesium carbonate (Kenboshi manufactured by Kamishima Chemical Co., Ltd.), and a cationic resin (Neofix RP manufactured by Nicca Chemical Co., Ltd.)
-70) and 0.01 part of an anionic high molecular weight retention improver.
A paper of m ² was made. Oxidized starch (MS3800 manufactured by Nippon Shokuhin Co., Ltd.) was applied at a concentration of 5% using a size press installed in the middle of the paper making machine, and the paper was finished in a conventional manner to obtain the recording paper of Example 1. Table 1 shows the results of measuring the inkjet suitability of this recording paper. Example 2 70 parts of LBKP with a water level of 350 ml and a water level of 400 ml
Pulp slurry consisting of 30 parts of NBKP and 10 parts of talc
1 part, 10 parts of magnesium oxide (Star Mag M manufactured by Kamishima Chemical Co., Ltd.), and 0.01 part of an anionic high-molecular weight retention improver were added, and the basis weight was 74 g/m ² using a Fourdrinier paper machine.
paper was made. A size press installed in the middle of the paper machine uses polyvinyl alcohol (manufactured by Kuraray Co., Ltd.).
A size press solution consisting of 3% PVA 117) and 2% cationic resin (Polyfix 601 manufactured by Showa Kobunshi Co., Ltd.) was deposited at 60 g/m ² including water and finished in a conventional manner to obtain the recording paper of Example 2. Table 1 shows the results of measuring the inkjet suitability of this recording paper. Comparative Example 1 A recording sheet of Comparative Example 1 was prepared in exactly the same manner as in Example 2 except that the internally added magnesium oxide in Example 2 was replaced with calcium carbonate. Comparative Example 2 The cationic resin in the size press liquid of Example 2 was replaced with an anionic resin (manufactured by Seiko Kagaku Co., Ltd., Star Gum A).
A recording sheet of Comparative Example 2 was prepared in exactly the same manner as in Example 2, except that -15) was replaced. These, Comparative Examples 1 and 2
Table 1 shows the results of measuring the inkjet suitability of the recording paper. Examples 3 to 6 80 parts of LBKP at a water level of 350 ml and a water level of 400 ml
Talc 15 to pulp slurry consisting of 20 parts of NBKP
1 part, and 0.01 part of an anionic polymeric retention agent were added thereto, and a paper having a basis weight of 78 g/m ² was made using a Fourdrinier paper machine. A size press installed in the middle of the paper machine produces polyvinyl alcohol (manufactured by Kuraray Co., Ltd.).
PVA117) 5%, cationic resin (Polyfix 601 manufactured by Showa Kobunshi Co., Ltd.) 2%, and magnesium hydroxide (Kamishima Chemical Co., Ltd. #200) 0.1% and 1%, respectively.
%, 5%, and 10% concentration of size press solution including water was deposited at 50 g/m ² and finished by a conventional method to obtain recording sheets of Examples 3, 4, 5, and 6, respectively. Table 1 shows the results of measuring the inkjet suitability of these recording papers. Comparative Example 3 A recording sheet of Comparative Example 3 was prepared in exactly the same manner as in Example 3, except that magnesium hydroxide was removed from the size press liquid of Examples 3 to 6. Table 1 shows the results of measuring the inkjet suitability of this recording paper. Example 7 In place of the size press liquid used in Examples 3 to 6, 2% oxidized starch (MS3800 manufactured by Nippon Shokuhin Co., Ltd.) and 4% synthetic silica (Nipseal LP manufactured by Nippon Silica Co., Ltd.) were used.
%, 2% magnesium oxide (Star Mag M, manufactured by Kamishima Chemical Co., Ltd.), and 1.5% cationic resin (Neofix RPD, manufactured by NICCA Chemical Co., Ltd.) was used. The amount of adhesion was 48 g/m ² including water. Other than this, the recording paper of Example 7 was prepared in exactly the same manner as in Examples 3 to 6. Table 1 shows the results of evaluating the inkjet suitability of this recording paper.
Shown below. Comparative Example 4 A recording sheet of Comparative Example 4 was prepared in exactly the same manner as in Example 7 except that magnesium oxide was removed from the size press liquid of Example 7. Comparative Example 5 Comparative Example 5 was prepared in exactly the same manner as in Example 7 except that the cationic resin was removed from the size press liquid of Example 7.
It was used as a recording paper. Table 1 shows the results of evaluating the inkjet suitability of the recording papers of Comparative Examples 4 and 5. Comparative Example 6 A recording sheet of Comparative Example 6 was prepared in exactly the same manner as in Example 7 except that magnesium oxide in the size press liquid was replaced with calcium chloride. Comparative Example 7 A recording sheet of Comparative Example 7 was prepared in exactly the same manner as in Example 7, except that the magnesium oxide in the size press liquid of Example 7 was replaced with calcium chloride and the cationic resin was omitted. Table 1 shows the results of evaluating the inkjet suitability of the recording papers of Comparative Examples 6 and 7.

[Table] (F) Effect of the invention Examples of light resistance of magenta M in Example 2 and Comparative Example 1, Examples 3 to 6 and Comparative Example 3, and Example 7 and Comparative Example 4 or Comparative Example 6 are shown below. As can be seen, the examples according to the present invention containing both a cationic resin and a magnesium compound have good light resistance and water resistance, and the effect is particularly remarkable in magenta, where light resistance is difficult to obtain. It is also found that calcium has no such effect, and only the combination with magnesium has this effect.

Claims (1)

[Claims] 1. In an inkjet recording paper that is mainly made of pulp fiber and is used for recording using a water-based ink containing a water-soluble dye, the recording paper contains a cationic resin and magnesium having a solubility in water of 1% by weight or less. An inkjet recording paper characterized by containing a compound.