JPH11321069A - Ink jet recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet mechanism medium having excellent ink absorbability, high printing density and high coating film strength. SOLUTION: In the ink jet recording medium comprising an ink receptive coating layer containing a noncrystalline silica and an adhesive on a support; the silica is a noncrystalline silica aged under the conditions of 40 deg.C or higher and a relative humidity of 80% or more. Further, in the medium, its aging time is 8 hours or more.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording method for recording on a recording medium using an aqueous ink, and more particularly to an ink jet recording medium having excellent ink absorbency, print density and coating strength.

[0002]

2. Description of the Related Art An ink jet recording system using an aqueous ink has a low noise at the time of recording, is easy to colorize, and is capable of high-speed recording. Applications to form printing and the like are being promoted. However, high-quality paper and coated paper used for general printing have poor ink absorbency, so the printed ink does not dry on the paper surface and remains for a long time, contaminating the equipment and continuously printed sheets. Practicality is poor because the image becomes dirty or the image becomes dirty. In order to solve such a problem, a recording paper having a low size (Japanese Patent Laid-Open No.
No. 3012), and a recording paper in which a water-soluble polymer is impregnated into a base paper internally containing a urea-formalin resin (Japanese Patent Application Laid-Open No. 53-49113). Recording papers coated with various kinds of porous inorganic pigments such as amorphous silica on the surface for the purpose of enhancing the color development and reproducibility of the ink (JP-A-55-515)
No. 83, JP-A-56-148585). Further, in order to obtain a high-definition image with reduced bleeding, the physical properties of these porous pigments are specified (JP-A-58-110287, JP-A-59-185690, JP-A-61-141584). ) Has been proposed and some results have been obtained.

However, in recent years, the technical development of ink jet printers has been remarkable, and higher quality has been required on the recording medium side as well as printer performance has been improved, and satisfactory qualities have not always been obtained with the above technology alone.

[0004] Many recent ink jet printers improve dot granularity by miniaturizing ink droplets and use low print density inks (so-called light color inks and photo inks) in order to obtain high image quality comparable to silver halide photographs. To improve the gradation expression, and furthermore, to improve the gradation expression by making the ink ejection amount per nozzle variable. With the adoption of these printers' new technology, the amount of ink ejected per unit area of the recording medium is much larger than that of conventional printers. Insufficiency and bleeding and stains on the image tended to occur. In order to solve this problem, there have been proposed a recording medium in which the coating amount of the ink receptive coating layer is increased, a recording medium using a pigment having a high ink absorbency, and a recording medium in which the mixing ratio of the adhesive is reduced. However, these recording media tend to cause a decrease in print density and a decrease in coating film strength. A decrease in print density impairs image reproducibility, a decrease in coating strength impairs writability with a pencil, and also causes powder drop due to peeling of the coating layer during cutting. Therefore, there has been a strong demand for an ink jet recording medium which has solved such a problem and has high ink absorbency and also has high print density and coating strength.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide an ink jet recording medium which has excellent ink absorbency, and further has a high print density and a high coating strength.

[0006]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that the use of amorphous silica after aging treatment under high-temperature and high-humidity conditions significantly improves the ink jet recording characteristics and coating film strength. This led to the completion of the present invention. The present invention includes the following aspects. [1] In an ink jet recording medium having an ink receptive coating layer containing amorphous silica and an adhesive on a support, the amorphous silica has a temperature of 40 ° C. or higher and a relative humidity of
An inkjet recording medium comprising amorphous silica that has been aged under 80% or more.

[2] The ink jet recording medium according to [1], wherein the aging time is 8 hours or more. [3] The inkjet recording medium according to [1] or [2], wherein the amorphous silica is a xerogel-based porous pigment. [4] The ink jet recording medium according to [1], [2] or [3], wherein the adhesive in the ink receptive coating layer contains a silanol-modified polyvinyl alcohol.

[5] The ink receptive coating layer contains a cationic resin, [1], [2],
The inkjet recording medium according to [3] or [4]. [6] The ink jet recording medium according to [1], [2], [3], [4] or [5], wherein the ink receptive coating layer is composed of two or more layers.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS That is, in an ink jet recording medium having an ink receiving layer containing amorphous silica and an adhesive on a support, a temperature of 40 ° C. or more and a relative humidity of 80 ° C.
% By using amorphous silica which has been subjected to aging treatment under the above conditions, an ink jet recording medium having high ink absorbency, excellent print density and excellent coating film strength can be obtained. Although there is no upper limit on the aging temperature, for example, up to about 100 ° C. is sufficient. The upper limit of the relative humidity is 100%. The appropriate time for the aging treatment of the amorphous silica of the present invention depends on the temperature and humidity conditions, but is preferably 8 hours or more, and particularly preferably 15 hours or more. There is no particular upper limit, but usually about 2 weeks is sufficient. Aging can be performed in powder state,
For example, it can be performed by storing amorphous silica in a paper bag in a chamber under the above temperature and humidity conditions.

By aging treatment under high temperature and high humidity conditions,
The details of the reason why high ink absorbency, print density, and coating strength are obtained are unknown, but aging deactivates the active silanol groups of the amorphous silica, and the paint properties and the properties of the amorphous silica and the ink. It is considered that the affinity is improved.

[0011] The structure of the amorphous silica used in the present invention is not particularly limited, but it is easy to control the ink receptivity. It is desirable to have one having a neutral structure. Further, a xerogel-based porous pigment other than silica can be used in combination. The xerogel-based porous pigment refers to a gel in a dry state, and has excellent absorbability for aqueous ink. Xerogel-based porous pigments of amorphous silica and other pigments include, for example, (1) a silica-based or hydrogel-forming substance such as aluminum hydroxide, alumina, or magnesium oxide as a raw material, and drying such a hydrogel. After xerogel, pulverize and classify. (2) In the state of a hydrogel, granules are formed into appropriate secondary and tertiary agglomerates, dried, and further heated to promote sintering, crystallization, etc., so that the primary particles of oxide Method to strengthen the use of (3) At the stage of producing urea-formalin resin, melamine-formalin resin, etc. in a suspension of fine particles such as colloidal silica, colloidal alumina, etc., the production conditions are adjusted to produce the desired secondary particle diameter. A method in which, after being formed into fine particles, they are dried and then used as sintered particles as necessary. Can be manufactured using various known methods,
It is commercially available. Agglomerated particle size (secondary particle size) of amorphous silica
Although not limited, for example, it is about 0.5 to ²⁰ μm, and the specific surface area is about 10 to 500 m ² / g.

The pigment contained in the ink receptive coating layer may be, for example, calcium carbonate, kaolin, talc, calcium sulfate, barium sulfate, titanium dioxide, zinc oxide, carbonate carbonate, etc. Inorganic pigments such as zinc, satin white, aluminum silicate, diatomaceous earth, calcium silicate, magnesium silicate, white carbon, alumina, aluminum hydroxide, etc., and organic pigments based on styrene, acrylic, urea resin, melamine resin, and benzoguanamine resin Can also be used in combination.

Examples of the adhesive for the ink-receiving coating layer include starch and derivatives thereof, carboxymethylcellulose, hydroxyethylcellulose, casein, gelatin, natural or semi-synthetic polymers such as soybean protein, polyvinyl alcohol and silanol-modified polyvinyl. Alcohol, polyvinyl alcohols including modified polyvinyl alcohol such as cation-modified polyvinyl alcohol, polyvinyl butyral resin, polyethylene imine resin,
Polyvinyl pyrrolidone resin, poly (meth) acrylic acid resin, acrylate resin, polyamide resin, polyacrylamide resin, polyester resin, urea resin, melamine resin, styrene / butadiene copolymer, methyl methacrylate / butadiene Known materials such as copolymers, aqueous solutions or aqueous dispersions of vinyl copolymer resins such as ethylene / vinyl acetate copolymers, and modified polymers in which anionic or cationic residues have been introduced into the above resins Can be exemplified. Above all, silanol-modified polyvinyl alcohol is preferable because a high coating film strength can be obtained.

Further, polyethyleneimine resin, polyamine resin, polyamide resin, polyamide epichlorohydrin resin, polyamine epichlorohydrin resin, polyamide polyamine epichlorohydrin resin,
Cationic polymer compounds such as polydiallylamine resins and dicyandiamide condensates can also be used in combination. This makes it possible to improve the water resistance of the image printed with the water-based ink.

If necessary, a pigment dispersant, a thickener,
Antifoaming agents, foam inhibitors, foaming agents, release agents, penetrants, wetting agents, thermal gelling agents, lubricants, dyes, optical brighteners, and various other auxiliaries known in the art may also be used. it can.

The ink receptive coating layer may be composed of two or more layers for the purpose of preventing the recording medium after printing from being uneven or wavy, so-called cockling. It is preferable to use a xerogel-based porous pigment and a non-xerogel-based pigment together in the coating layer close to the support.

Means for coating the ink receptive coating layer include commonly used coatings such as a size press, a gate roll, a roll coater, a bar coater, an air knife coater, a rod blade coater, a blade coater, a die coater, and a curtain coater. It can be appropriately selected from the construction means. Coating weight not particularly limited and may be determined depending on the recording quality, 2 g / m ² or more and 40 g / m ² or less.

The support is not particularly limited, and may be acidic paper, neutral paper,
In addition to papers such as coated papers, synthetic papers, resin films, laminated papers and the like can be used.

As cellulose pulp as a main component of paper, chemical pulp such as softwood bleached kraft pulp (hereinafter, NBKP) and hardwood bleached kraft pulp (hereinafter, LBKP), G
Examples include mechanical pulp such as P, BCTMP, and MP, pulp obtained from non-wood raw materials such as kenaf, and pulp for papermaking represented by pulp such as DIP. Mainly this, polyethylene,
Polyolefin fibers such as polypropylene, ethylene / propylene copolymer, polystyrene, ethylene / vinyl acetate copolymer, halogen-containing polymers such as polyvinyl chloride and polyvinylidene chloride, and polyamide fibers such as 6-nylon and 66-nylon , Polyethylene succinate, polycaprolactone, polylactic acid, polyhydroxybutyrate
An aliphatic polyester fiber such as a valerate copolymer, a vinylon fiber or the like may be mixed.

Also, if necessary, inorganic pigments such as talc, kaolin, calcined kaolin, calcium carbonate, white carbon, amorphous silica, diatomaceous earth, titanium oxide, activated clay, barium sulfate, urea formalin resin, nylon powder, polyethylene powder The organic pigment can be prepared by a usual method using acidic or neutral papermaking by adding an organic pigment as a filler. Further, sizing agents represented by rosin-based sizing agents, alkenyl succinic anhydrides, alkyl ketene dimers, etc., starches such as oxidized starch, enzyme-modified starch, cation-modified starch, esterified starch, etherified starch, methylcellulose, ethylcellulose , Carboxymethylcellulose, methoxycellulose, hydroxycellulose, completely or partially saponified polyvinyl alcohol, carboxy-modified polyvinyl alcohol, polyvinyl alcohols such as silicon-modified polyvinyl alcohol, polyacrylamide, polyvinylpyrrolidone, acrylic acid amide-acrylate copolymer, Acrylic acid amide / acrylate / methacrylic acid copolymer, styrene / maleic anhydride copolymer alkali salt, isobutylene / maleic anhydride copolymer alkali salt, Water-soluble polymers zein etc., polyvinyl acetate, polyurethane, polyacrylic acid,
Polyacrylate, polybutyl methacrylate,
Paper to which an adhesive represented by a latex such as a styrene / butadiene copolymer, a vinyl chloride / vinyl acetate copolymer, a styrene / butadiene / acrylic copolymer or the like is internally added or coated can be used as appropriate.

[0021]

The present invention will be described in more detail with reference to the following examples, but it should be understood that the present invention is by no means restricted to these examples. In the examples, parts and% mean parts by weight and% by weight. The methods for measuring various physical properties in the examples are shown below. 1) Print density Seiko Epson inkjet printer PM-700
Printing was performed using C at a recording density of 720 dpi, and the printing density was measured. As a result, those that showed excellent print density
B was rated as slightly thin but at a level that was practically acceptable, and C was rated as too thin to withstand practical use.

2) Print Drying Property In order to evaluate the ink absorbency, the print drying property was evaluated.
Seiko Epson inkjet printer PM-700
Using C, a 100% density print was performed at a recording density of 720 dpi, the dry state of the portion was visually evaluated, and the time until the gloss disappeared was used as a measure of print dryness. A indicates that the gloss disappears within a few seconds after discharge, A indicates that the gloss remains for several seconds or more, but B indicates that there is no practical problem, and C indicates that the gloss remains for several tens seconds or more and may cause a practical problem. And ranked. 3) Bleed Bleed was evaluated for evaluation of ink absorbency. 200% density printing was performed at a recording density of 720 dpi using an inkjet printer PM-700C manufactured by Seiko Epson Corporation, and the bleeding state of adjacent portions of different colors was visually evaluated.
As a result, those with little bleeding
B is a level that is slightly bleeding but has no practical problem.
Rank C.

4) Coating strength The state of the surface of the recording medium when a scotch clear tape (trade name: CH-24, manufactured by Sumitomo 3M) was adhered to the surface of the coating layer of the ink jet recording medium, and the tape was immediately peeled off was adhered. It was evaluated visually. As a result, the film surface was hardly peeled, and the film surface was hardly peeled, A was rated, B was partially peeled, and C was completely peeled. 5) Cock ring Seiko Epson inkjet printer PM-700
Using C, printing was performed at a recording density of 720 dpi at a density of 200%, and the occurrence of cockling was visually evaluated. As a result, a case where cockling was not recognized at all was A, and a case where cockling was slightly recognized but there was no practical problem.
B, those with larger cock rings were ranked C.

[0024] Example 1 basis weight 144 g / m ink receptive coating layer coating solution 1 on one surface of woodfree paper of ² (Formulation 1) Meyer bar so as the coating amount after drying of 8 g / m ² and The coating amount after drying the coating liquid 2 (formulation 2) for the ink receptive coating layer is 8 g.
/ M ² by using a Mayer bar to apply and dry to obtain an ink jet recording medium. The xerogel-based porous amorphous silica had a temperature of 40 ° C and a relative humidity of 90 in advance.
%, Which was left in a chamber for 24 hours and subjected to aging treatment.

Prescription 1 Calcined Kaolin (Ansilex, Engelhard Co.)
60 parts, xerogel-based porous amorphous silica (Fine Seal X-45, manufactured by Tokuyama Corporation, average particle diameter 4.3 μm, specific surface area 29
0 m ² / g) 40 parts, polyvinyl alcohol (PVA117, manufactured by Kuraray) 5 parts, SBR latex (JSR0617, manufactured by Asahi Kasei Corporation) 10 parts. Formulation 2 xerogel-based porous amorphous silica (Fine Seal X-6
0, manufactured by Tokuyama Corporation, average particle size 5.9 μm, specific surface area 290 m
² / g) 100 parts, silanol-modified polyvinyl alcohol (R-1130, Kuraray) 20 parts, SBR latex (JSR0
617, Asahi Kasei Corporation) 5 parts, polydimethylammonium chloride-based cationic resin (PAS-H-10L, manufactured by Nitto Boseki)
5 copies.

Example 2 An ink jet recording medium was obtained in the same manner as in Example 1.
However, the aging treatment conditions for the xerogel-based porous amorphous silica were a temperature of 50 ° C., a relative humidity of 80%, and a treatment time of 20 hours. Example 3 An ink jet recording medium was obtained in the same manner as in Example 1.
However, the aging treatment conditions for the xerogel-based porous amorphous silica were a temperature of 55 ° C., a relative humidity of 90%, and a treatment time of 10 hours.

Example 4 An ink jet recording medium was obtained in the same manner as in Example 1.
However, Fine Seal X-45 (manufactured by Tokuyama) was used instead of Fine Seal X-60 (manufactured by Tokuyama) as the xerogel-based porous amorphous silica used in Formulation 2. Example 5 An ink jet recording medium was obtained in the same manner as in Example 1.
However, instead of Fine Seal X-60 (manufactured by Tokuyama) used in Formulation 2, carplex FPS-101 (manufactured by Shionogi & Co., Ltd., average particle size 1.
2 μm, specific surface area 260 m ² / g).

Example 6 An ink jet recording medium was obtained in the same manner as in Example 1.
However, instead of using Fine Seal X-60 (manufactured by Tokuyama), Fine Seal X-45 (manufactured by Tokuyama) was used as the xerogel-based porous amorphous silica used in Formulation 2. Aging treatment conditions for silica
The temperature was 50 ° C., the relative humidity was 90%, and the processing time was 24 hours. Example 7 An ink jet recording medium was obtained in the same manner as in Example 1.
However, instead of the polydimethylammonium chloride-based cation resin (PAS-H-10L, manufactured by Nitto Boseki) of Formulation 2, a polydiallyldimethylammonium chloride-based cation resin (Unisense CP-103, manufactured by SENKA) was used.

Example 8 An ink jet recording medium was obtained in the same manner as in Example 1.
However, the coating liquid 1 for the ink-receiving coating layer (Formulation 1) was applied without coating the coating liquid 1 for the ink-receiving coating layer (Formulation 1). Example 9 In the same manner as in Example 8, an ink jet recording medium was obtained.
However, instead of silanol-modified polyvinyl alcohol (R-1130, manufactured by Kuraray Co., Ltd.), polyvinyl alcohol (PVA117, manufactured by Kuraray Co., Ltd.) was used as the adhesive used in Formulation 2.

Comparative Example 1 An ink jet recording medium was obtained in the same manner as in Example 1.
However, the aging treatment conditions for the xerogel-based porous amorphous silica were a temperature of 25 ° C., a relative humidity of 80%, and a time of 24 hours. Comparative Example 2 An ink jet recording medium was obtained in the same manner as in Example 1.
However, the aging treatment conditions for the xerogel-based porous amorphous silica were a temperature of 40 ° C., a relative humidity of 50%, and a time of 24 hours.

Comparative Example 3 An ink jet recording medium was obtained in the same manner as in Example 1.
However, the aging treatment conditions for the xerogel-based porous amorphous silica were a temperature of 30 ° C., a relative humidity of 60%, and a time of 24 hours. Comparative Example 4 An ink jet recording medium was obtained in the same manner as in Example 1.
However, the coating liquid 1 for the ink-receiving coating layer (Formulation 1) was applied without coating the coating liquid 1 for the ink-receiving coating layer (Formulation 1). Also, as xerogel-based porous amorphous silica,
Fine Seal X-45 (manufactured by Tokuyama) was used instead of Fine Seal X-60 (manufactured by Tokuyama). Further, the aging treatment conditions of xerogel-based porous amorphous silica,
The temperature was 40 ° C., the relative humidity was 70%, and the time was 5 hours.

Comparative Example 5 An ink jet recording medium was obtained in the same manner as in Example 1.
However, as a xerogel-based porous amorphous silica used in Formulation 2, Carplex FPS-101 (manufactured by Shionogi & Co., Ltd.) was used instead of Fine Seal X-60 (manufactured by Tokuyama Corporation). The xerogel-based porous amorphous silica was subjected to aging treatment at a temperature of 40 ° C., a relative humidity of 70%, and a time of 10 hours. Comparative Example 6 An ink jet recording medium was obtained in the same manner as in Example 1.
However, the xerogel-based porous amorphous silica was not aged at all.

Table 1 shows the results of evaluating the recording density, print drying property, bleeding, cockling, and coating film strength of the above 15 types of recording media.

[0034]

[Table 1]

[0035]

As is clear from Table 1, the examples of the present invention were excellent ink jet recording media in all of the print density, print dryness, bleeding, cockling, and coating strength as compared with the comparative examples. . That is, the ink jet recording medium of the present invention is excellent in ink absorbency, and has high printing density and high coating film strength.

Claims (6)

[Claims] 1. An ink jet recording medium comprising an ink-receiving coating layer containing amorphous silica and an adhesive on a support, wherein the amorphous silica has a temperature of 40 ° C. or higher and a relative humidity of 80% or higher. An inkjet recording medium comprising amorphous silica that has been aged under the following conditions: 2. The ink jet recording medium according to claim 1, wherein the aging processing time is 8 hours or more. 3. The ink jet recording medium according to claim 1, wherein the amorphous silica is a xerogel-based porous pigment. 4. The ink jet recording medium according to claim 1, wherein the adhesive in the ink receptive coating layer contains a silanol-modified polyvinyl alcohol. 5. The ink receiving coating layer according to claim 1, wherein the ink receiving coating layer contains a cationic resin.
The ink-jet recording medium as described in the above. 6. The ink jet recording medium according to claim 1, wherein the ink receptive coating layer comprises two or more layers.