JPS6147290A - Ink jet recording medium - Google Patents

Abstract

PURPOSE:To improve the water resistance and light fastness of an image and to obtain a high speed recording medium with high accuracy and excellent storage stability, by containing a weak acid salt of an alkali metal and/or a double salt thereof in a recording medium forming a recording image by using aqueous ink containing a water-soluble dye. CONSTITUTION:In an ink jet recording medium forming a recording medium by using aqueous ink containing a water-soluble dye, the recording medium contains a weak acid salt of an alkali metal and/or a double salt thereof. As the weak acid salt of the alkali metal and/or the double salt thereof, carbonate, oxalate, acetate and silicate of lithium, sodium, potassium and rubidium or double salts thereof are designated but, pref., carbonate, oxalate and silicate of potassiim and/or sodium or double salts thereof are used and potassium carbonate and/or a double salt thereof is especially pref. By containing the weak acid salt of the alkali metal, light fastness, especially, the light fastness against black (BK) and magneta (M) is improved.

Description

Detailed Description of the Invention (5) Industrial Application Field The present invention relates to a recording medium recorded using ink, and in particular, the medium has high density images and characters recorded on the medium, and has high absorbency and recording properties. This invention relates to an inkjet recording medium that has excellent image storage stability.

CB) Prior art and its problems The inkjet recording method uses various operating principles to fly minute droplets of ink and attach them to a recording medium such as a piece of paper to record an image, such as a single character. high speed,
It has features such as low noise, easy multicolor printing, wide flexibility in recording patterns, and no need for development or fixing, making it suitable for a variety of applications 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 a plate-making method or printing using a color photographic method, making it ideal for applications that require fewer copies to be produced. In this case, since the process using photographic technology is inexpensive, 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, which are used for ordinary printing and writing, as the recording medium used in this inkjet recording method. However, as the performance of print/eject recording devices increases, such as faster speeds, higher definition, or full-color printing, and as the applications expand, the recording media are also required to have sophisticated characteristics. friend. In other words, the recording medium must have high ink dot density, bright and colorful tones, ink absorption is fast and the ink does not run out or smear even when ink dots overlap, and the ink dots are The lateral diffusion of the dye should not be excessively large, and the periphery should be smooth and not blurred, and the dye should be resistant to exposure to ultraviolet rays, oxygen in the air, or water. It is required not to reduce it, but preferably to increase it.

These problems? Several proposals have been made to solve this problem. For example, JP-A No. 52-53012 V
Is C a paint for surface treatment on low-sized base paper? Inkjet recording paper made by moistening the paper was published in Japanese Unexamined Patent Application Publication No. 53-4
No. 9113 discloses an inkjet recording paper in which a sheet containing urea-formalin resin powder is impregnated with a water bathing polymer. These patterned paper-type inkjet recording papers absorb ink quickly, but
The drawbacks are that the periphery of the dot tends to be blurred and the dot density is low.

Further, JP-A No. 55-5830 discloses a print recording paper in which an ink-absorbing coating layer is not provided on the surface of the support, and JP-A No. 55-51583 discloses an ink-absorbing coating layer on the surface of the support. Non-glue silica powder as pigment? Further, Japanese Patent Application Laid-open No. 11829/1983 discloses an example of a two-layered tone sheet smearing paper having different absorption rates. These coated paper type inkjet recording papers are improved in terms of dot diameter, dot shape, dot 6 degrees, and color tone reproducibility compared to general paper type inkjet paper, but these recording media Most of the inks used for this purpose are water-based inks that use water-bathable dyes, and if the image formed on the recording medium is exposed to water or holes, the dye will dissolve again and ooze out, resulting in the damage to the recorded material. Of course, there are problems that significantly reduce the value.

Therefore, the ninth step to improve this shortcoming is, for example, JP-A-55
No. 53591 has an example of applying a metal water-soluble salt to the recording surface, and Makoto JP-A No. 56-84992 has an example of a recording medium containing a polycationic polymer electrolyte on the surface.
JP-A-55-150396 discloses a method of applying a water-resistant agent that forms a lake with the dye in the ink after inkjet recording, and JP-A-56-58869 describes a method of applying a water-resistant agent to form a lake with the dye in the ink. Disclosed are methods for insolubilizing the water-bathable polymer and for making the sheet water resistant after inkjet recording on the recording sheet.

However, with these methods, the effect of water resistance is weak, or the water resistance ratio agent causes some kind of reaction with the dye, reducing the shelf life of the dye and causing fC9, making it impossible to achieve both sufficient water resistance and light resistance. A very difficult and hot sentence.

(Q. Purpose of the Invention The present invention improves the water resistance and light resistance of an aqueous ink image in an inkjet recording medium in which a recorded image is formed by injecting an inkjet aqueous ink onto the entire recording medium, and It is our objective to provide such high-speed, high-definition recording media with excellent storage stability.

(To) Structure and operation of the invention That is, the present invention provides an aqueous ink containing at least one water-soluble dye selected from direct dyes, acid dyes, reactive dyes, basic dyes, and food colorings. The recording medium used to form a recorded image is an inkjet recording medium characterized in that it contains a weak acid salt of an alkali metal and/or a double salt thereof.

In the present invention, the light fastness of the dye contained in the water-based ink is improved by containing a weak acid salt of an alkali metal and/or its double salt, but it is not clear why this happens. do not have.

In the present invention, in addition to weak alkali metal salts, the recording medium contains inorganic pigments, adhesives, and water-resistant dye rings.
It can be included. The inorganic pigment is preferably a porous inorganic pigment that has excellent ink absorption ability. -1.9 As a water resistance agent, cationic ceramic resin, especially light resistance? Quaternary cationic resins are preferably used because they cause less reduction.

The weak acid salts of alkali metals and/or their double salts as used in the present invention refer to carbonate-oxalates, acetates, silicates, and double salts of lithium, sodium, potassium, rubidium, etc., but preferably are potassium and/or sodium carbonates, oxalates, silicates, and double salts thereof, particularly preferably potassium carbonate and/or double salts thereof. The amount of these salts used varies depending on the salt, but is generally from 0.01 to 2017, preferably from 0.02 to 2017.
I owe you 10η.

The porous inorganic pigment preferably used in combination with the weak acid salt of the alkali metal in the present invention is made by aggregating primary particles of fusilica or water-containing aluminum oxide and having an average secondary particle size of 0.5 μm to 30 μm. These synthetic silicas or water-use aluminum oxides are made into dry powders, and when synthesized from water-bathable raw materials in a water-bath solution, their primary particles have a size of several micrometers to several hundred micrometers, and have self-cohesive properties. Porous inorganic pigments can be made into porous inorganic pigments by drying, pulverizing, and classifying, or by using a spray dryer or the like during drying to adjust the particle size to the desired size.

In addition, if synthetic silica or water-use aluminum oxide is a fine powder of 1 μm or less, it is dispersed in water, added with a binder or adhesive, dried, pulverized and classified71, and then spray-dried with a spray dryer. By doing so, it is also possible to obtain a porous inorganic pigment having an average secondary particle diameter of 0.5 μm to 30 μm.

Furthermore, in order to form fine water-dispersed substances such as colloidal silica and colloidal alumina into particles with a size of 0.5 μm or more, a fine particle suspension is used as disclosed in U.S.P-3,855,172. It is also possible to produce a urea-formalin resin or the like in turbid water, and then granulate it to a desired secondary particle size by adjusting the production conditions to form a porous inorganic pigment.

The synthetic silica referred to in the present invention refers to dry process silica produced by thermal decomposition of silicon tetrachloride, so-called white carbon such as double decomposition precipitation products produced by sodium silicate acid, carbon dioxide, ammonium salt, etc., and produced by sodium silicate acid. Silica sol obtained by thermal decomposition or seven layers of ion exchange resin, or colloidal silica obtained by heating and aging this silica sol, is gelled on the silica sol, and by changing the formation conditions t, it is possible to obtain particles with a size of several millimicrons to several tens of millimicrons. The primary particle becomes a three-dimensional secondary particle with silokinane bonding kL7, and furthermore, silica gel, silica sol, sodium silicate, aluminum/sodium acid, etc.8 as a starting material.
So-called synthetic molecular sheep produced by heating at 0°C to 120°C is a synthetic silicon compound mainly composed of silicon dioxide.

The porous aluminum oxide referred to in the present invention is an aluminum salt such as aluminum sulfate, aluminum nitrate, aluminum chloride and the like, or an alkali metal salt of aluminate such as sodium or potassium salt of aluminate, or both. Is this a gel obtained by neutralizing a water-soluble aluminum compound from a water bath solution or by ion-exchanging it using an ion-exchange resin? It is called hydrogel, but 7
Usually, it is washed, removed with salt, and then dried.

It is obtained by making it into xerogel. By using spray drying or the like for drying, it is possible to form a powder suitable for blending into a coating solution.

It is also possible to make it into a powder by pulverizing and classifying it after drying it in the form of an LC block. The water-conserving oxide obtained after drying in this way has most, if not all, of the free water removed, and some of the friendly bound water is usually removed, leaving most of the structure intact. is irreversibly set into a porous solid. The pore diameter of the porous solid thus obtained is usually 50A to 5000A, and the surface charge when the secondary particles are dispersed in water becomes a glass charge (cationic).

In the present invention, the above porous inorganic pigments can also be used in combination with the following inorganic or organic pigments. In this case, the porous inorganic pigment is used in an amount of at least 20% by weight of the total pigment, preferably at least 40 weight f1. Examples of inorganic pigments that can be used in combination include light calcium carbonate, heavy carbonate calcium, and kaolin (
white clay), Merck.

Calcium sulfate, barium sulfate, titanium oxide, zinc oxide-zinc sulfide, zinc carbonate, satin white.

aluminum silicate, diatomaceous earth, calcium silicate,
Examples of white pigments and organic pigments such as magnesium silicate, synthetic amorphous silica, aluminum hydroxide, alumina, and lithopone include styrene plastic pigments, acrylic glass pigments, microcapsules, and urea resin pigments.

The cationic resin referred to in the present invention refers to a monomer, oligomer or polymer dissolved in water that dissociates over time and becomes cationic, preferably containing a quaternary ammonium group, particularly preferably the following (1) to ( ) to the structure expressed by the general formula '! e e R1-N-Rs・Y In the formula, the ratio 1- R2, "3 is an alkyl group 1m is 1-7, n
represents 2 to io, and y represents an acid group.

(II) ~ (In the formula of M, R1 and 几2 are -0H5, -0H2
-0)(,, -0H2-OH2-0)(, Y represents an acid group.

(V) Polyalkylene/polyamine dicyandiamide ammonium salt condensate (B) Polyamide epichlorohydrin resin.

The compound represented by the general formula (1) is 1, for example, Nalpoly-
607 (manufactured by Nalco Chemical Co., Ltd.) or Polyfix 601 (manufactured by Showa Kobunshi Co., Ltd.).

The compounds represented by formulas (If) to (Foundation) are polysialylamine derivatives, which can be obtained by determining the ring specific gravity of diallylamine compounds, and are available from Percoll 1697 (Allied Colloid Co., Ltd.), Cat Floc (Calgon Corp.
), PAS (Nittobo Co., Ltd.), Neofix RPD (manufactured by NICCA Chemical Co., Ltd.), and the like.

Furthermore, examples of the compound represented by the general formula (V) include Neofix RP-70 (Nicca Chemical Co., Ltd.).

17' is represented by the general formula (VD), Evinox 1301A (7" Ikk Percules Co., Ltd.), Kaimen 557H (Ikk Percules Co., Ltd.), Polyfix 301 (Showa Kobunshi Co., Ltd.), etc. I can list them.

The content of these cationic resins represented by formulas (I) to (VD) is usually 0.1 to 4%, preferably 0.2 to 4%.
Water resistance can be improved by using 2θ.

What are the methods of applying these porous inorganic pigments, cationic resins, and alkali metal weak acid salts and/or their double salts to recording media? Disperse or dissolve in water, add commonly used adhesives, inorganic pigments and other additives if necessary to form a coating solution, and use size press equipment, gate roll coaters, air knife coaters, blade coaters, spray equipment, etc. Apply and dry. Examples of adhesives include:

Oxidized Ill, etherified starch, cellulose derivatives such as carboxymethylcellulose, hydroxyethylcellulose, casei/, gelati/, soybean protein.

Polyvinyl alcohol and its derivatives, maleic anhydride resin 1 Conjugated diene polymer latex such as ordinary styrene-butadiene copolymer, methyl methacrylate-butadiene copolymer, polymer or copolymer of acrylic ester and methacrylic ester acrylic polymer latex such as ethylene-vinyl acetate copolymer, vinyl polymer latex such as ethylene-vinyl acetate copolymer, functional group-modified polymer latex with monomers containing functional groups such as carboxyl groups of these various polymers, and melamine. Water-based adhesives such as thermosetting synthetic resins such as resins and urea resins, and synthetic resin adhesives such as polymethyl methacrylate, polyurethane/resin, unsaturated polyester resins, vinyl chloride-vinyl acetate copolymers, polyvinyl butyral, and alkyd resins. Agents may be used alone or in combination. These adhesives are used in an amount of 2 to 100 parts, preferably 5 to 30 parts, per 100 parts of the pigment, but as long as the amount is sufficient to bind the pigment, the ratio can be adjusted to reduce the frame structure or create a void. Number nine, which makes it extremely small.
Undesirable.

Other additives include pigment dispersants and thickeners.

Fluidity modifier, antifoaming agent, foam suppressor, mold release agent, foaming agent, penetrant 1 coloring dye 1 coloring pigment, fluorescent whitening agent, ultraviolet absorber,
Antioxidants, preservatives, anti-pepper agents, waterproofing agents, etc. can all be added as appropriate.

As the support, a sheet material such as 5 paper or a thermoplastic resin film is used. For paper, no sizing agent added or appropriate sizing? Good paper may or may not contain filler.

For thermoplastic films, polyester, polystyrene, polyvinyl chloride, polymethyl methacrylate,
Transparent films such as cellulose acetate, polyethylene/polycarbonate, and white opaque films filled with white pigment or formed by fine foaming are used. As a white pigment to be filled.

For example, many materials such as titanium oxide, calcium sulfate, carbonate, calcium, silica, clay, Merck, zinc oxide, etc. are used.

In addition, these resin films were pasted on the surface of the paper.
It is also possible to use so-called laminated paper, which is processed using molten resin. A subbing layer or corona discharge machining may be applied to improve the adhesion between the resin surface and the ink receiving layer.

A sheet coated on a support can be used as a recording sheet according to the present invention as it is, but it can be heated with a super calender/dar, cross calender, etc. and/or passed between roll nips under pressure to improve its surface smoothness. It is also possible to give.

In this case, the degree of processing may be limited because excessive processing by supercalender processing will reduce the ink absorbency due to the voids formed between the nine particles.

The water-based ink referred to in the present invention includes the following colorant and liquid medium,
A recording liquid consisting of other additives.

The coloring agent is a water-soluble dye selected from direct dyes, @-based dyes, basic dyes, reactive dyes, food colorings, and the like.

fcg, water and various water-soluble organic solvents 1 as the medium.
For example, 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, sequestering agents, antifungal agents, viscosity regulators, surface tension regulators, wetting agents, surfactants, antioxidants, ultraviolet absorbers, and rust inhibitors. I can do it.

Inkjet suitability was measured using the following method.

The color densities are for images obtained by solid printing using Sharp's Inkjet Color Image Gli/Tar (IO-700) with cyan (C), maze/li (foundation) to yellow (1), and black (Bk) inks. The concentration was measured using a Macbeth densitometer RD-514, and the critical value was used.

Light resistance is determined by Canon's inkjet printer (A-
1210) One xenon fade meter (manufactured by Suga Test Instruments, FAL-25X-HCL model) for the image area obtained by printing 4 peta marks with C, M, Y, and Bk inks using Kongo.
So 40 degrees Celsius, 60 inches, illuminance 41W/7? ! The color density before and after irradiation was measured using a Macbeth densitometer D514, and the color density after irradiation was divided by the color density before irradiation and expressed as a percentage of the irradiation value or light resistance (residual rate).几.

Water resistance was determined by printing with C, M, Y, and Bk inks using the same Canon inkjet printer. Measured with meter RD514, concentration after immersion? ! "90% divided by the concentration before immersion?Water resistance value. The higher the value, the better the water resistance.

The absorption speed is calculated by using a Sharp or Canon inkjet printer, feeding the paper immediately (about 1 second) after solid red printing (magenta - yellow), and applying it to the paper presser roll or finger. 90 Furthermore, the absorption capacity was determined by using a 1/10 solution of polyethylene glycol (PVA117)/water 71.
The solution was brought into contact with a fixed area of the ink-receiving layer for 10 seconds at 0°C, the excess liquid was removed with absorbent paper, and the weight of the solution absorbed into the ink-receiving layer was measured and calculated as grams per square meter. Use the value.

(G) Examples The present invention will be described below with reference to Examples, but the invention is not limited to these examples. In the examples, parts and parts are expressed as parts by weight and t%.

Example 1 LBKP 80 parts with water level 370 m 1 csf, p Fisheries 41
NBI of 0+n1csf (P2O part, talc for internal filling 10
Department.

3 parts of clay for internal filling, Kneefor 100 for rosin sizing agent
Deitsku Herkieles GmbH i) 0.5 g.

From a slurry consisting of 2.5 parts of band, a Fourdrinier paper machine is used to produce tsubo * 68 ? I-spine base paper was made into paper, and at the time of paper making, 1.5P or more of oxidized starch was attached using a size press machine to completely produce acid coated base paper. The Steckigt size degree of this paper is 33
A friend in seconds.

As a coating liquid, 100 parts of synthetic silica (Si-Uide 620. Fuji Deguiso/Company), which is a porous inorganic pigment, and polyvinyl alcohol (PVA117, manufactured by Kuraray Co., Ltd.), which is a water bathing resin.
90 parts, 10 parts of cationic resin Polyfix 601 (manufactured by Showa Kobunshi Co., Ltd.), 10 parts of potassium carbonate (K2COs)
An aqueous coating with a concentration of 16% consisting of a small amount of antifoaming agent and a fluorescent agent was prepared, and it was coated on the acidic base paper with an air knife coater to a solids content of 9%, and dried. Then, it was lightly passed through a super calendar and used as the recording paper of Example 1. The Beck smoothness of this recording paper was 105 seconds. Is this record sheet suitable for Inokjet? Evaluation and definite results? It is shown in Table 1.

Comparative Example 1 Potassium carbonate from the coating solution of Example 1? Nine pieces were removed in exactly the same manner as in Example 1 to obtain a recording sheet of Comparative Example 1. The Beck smoothness of this recording paper was 102 seconds. The inkjet suitability of this recording paper was evaluated and the results are shown in Table 1.
Shown below.

Example 2 The cationic resin was removed from the coating solution of Example 1, and the rest was *
Recording paper of Example 2 was obtained in exactly the same manner as in Stream Side 1.

The Beck smoothness of this recording paper is 95 seconds. This recording paper was evaluated for inkjet suitability, and the 7'C results are shown in Table 1.

Example 3 Potassium charcoal in the coating liquid of Example 1? The recording paper of Example 3 was prepared in exactly the same manner as in Example 1 except for the nine substituted potassium oxalate. The Bekk smoothness of this recording paper was 112 seconds. Table 1 shows the results of evaluating the inkjet suitability of this recording paper.

Comparative Example 2 A recording sheet of Comparative Example 2 was obtained in the same manner as in Example 1 except that potassium chloride r was used in place of potassium carbonate in the coating solution of Example 1. The Beck smoothness of this recording paper was 110 seconds. The results of inkjet suitability evaluation for this recording paper are shown in Table 1.

Examples 4 to 9 80 parts of LBKP with door water level of 370 m1 csf, reactor water level of 40
0m/! 20 parts of csf's NBKP, 13 parts of heavy calcium carbonate, 1 part of cationic starch, 0.
From a slurry consisting of 12 parts of polyalkylene/polyamine epichlorohydrin resin and 0.4 part of polyalkylene/polyamine epichlorohydrin resin, a fourdrinier paper machine was used to produce a tsubo fE of 68? /m'' base paper [was made], and during papermaking, oxidized starch was attached at a solid content of 1.!M/i using a size press machine to produce a neutral coated base paper.The Steckigt sizing degree of this base paper was 35 seconds. As the first degraded solution, mix 1 synthetic silica with 100 parts of Tsubu Seal LP1 (manufactured by Nippon Silikani Gyo Co., Ltd.), disperse it in 400 parts of water, pass the slurry through a Viscomill 7 times, grind the agglomerated particles, and add 15 parts of polyvinyl alcohol. An aqueous first coating solution with a concentration of 18% was prepared, and it was spread on the neutral coated base paper using an air knife coater so that the solid content was 131/R, and dried to prepare an undercoat paper 7. Then, it was synthesized as a second coating solution. 100 parts of silica (Zyroid 74, Fuji Deguison Co., Ltd. 1) - 40 parts of water-soluble resin polyvinyl alcohol-# (PVAI 17, manufactured by Kuraray Co., Ltd.), Neofix R as a cationic resin
7 parts of PD (manufactured by NICCA CHEMICAL CO., LTD.), 1 part, 5 parts, 10 parts to 20 parts, 40 parts, and 60 parts of potassium carbonate, and a small amount of other antifoaming agent. Then, use an air knife coater to coat the first coating solution on paper so that the solid content is 51 cm, and dry. Then, the sheets were supercalendered seven times to obtain recording sheets of Examples 4.5-37.8-9, respectively. Table 2 shows the results of evaluating the inkjet suitability of this recording paper.

Comparative Example 3 A recording paper binding box of Comparative Example 3 was prepared in the same manner as in Examples 4 to 9, except that no potassium carbonate was added to the fC second coating liquid used in Examples 4 to 9. This recording paper was evaluated for inkjet suitability, and the results are shown in Table 2.

Example 10 A recording sheet of Example 10 was obtained in exactly the same manner as in Examples 4 to 9, except that 10 parts of sodium silicate was used in place of potassium carbonate in Example 6. The inkjet suitability of this recording paper was completely evaluated and the ratio results are shown in Table 2.

Example 11 Recording paper 2 of Example 11 was obtained in exactly the same manner except that 10 i'i of sodium potassium carbonate was used in place of the potassium carbonate used in Example 6. This recording paper was evaluated for inkjet suitability, and the results are shown in Table 2.

Comparative Examples 4 to 7 K used in Example 10 in place of sodium phosphosilicate
C1, NaCL, Na2SO4, CaCl2' (others used were 51!), and recording sheets of Comparative Examples 4, 5, 6.7. were obtained in exactly the same manner as in the flow side 10. These recording sheets have inkjet suitability. The rW titer 7'C results are shown in Table 2.

CFI Effects of the Invention Weak Salt of Alkali Metal according to the Invention Kanakura M Shirinji Flow Side 1
In No. 11 to 11, the light resistance, especially the light resistance of black (Bk) and magenta (goods), was significantly improved compared to the comparative example that did not contain it, and it was recognized that it is excellent as an inkjet recording medium. It will be done.

Claims (5)

[Claims] (1) An inkjet recording medium that forms a recorded image using an aqueous ink containing a water-soluble dye, characterized in that the recording medium contains a weak acid salt of an alkali metal and/or a double salt thereof. recoding media. (2) The inkjet recording medium according to claim 1, wherein the alkali metal is potassium and/or sodium. (3) The inkjet recording medium according to claim 1, wherein the weak acid salt is at least one of carbonate, oxalate, and silicate. (4) Claim 1, wherein the alkali metal weak acid salt and/or its double salt is potassium carbonate and/or its double salt.
The inkjet recording medium described in Section 1. (5) The inkjet recording medium according to claim 1, 2, 3 or 4, wherein the recording medium contains a cationic resin.