JP2001010213A - Ink jet recording body and recording method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the ink absorbing capability, print an image of a high grade at a high speed, increase the printing density, and prevent bleeding from occuring in an ink jet recording method for an ink jet printer or protter or the like using a pigment ink. SOLUTION: This recording body is constituted by providing an ink receiving layer containing an amorphous silica of which the oil absorbing amount is 250 ml/100 g or higher and a binder, on a supporting body. In this case, the ink receiving layer further contains a cationic resin of a high cation strength, wherein the cation strength measured by a colloidal titration method is not less than 4.5 m equivalent, and not more than 8 m equivalent.

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 used for image recording and printing, and more particularly, to an ink-jet recording method using a pigment ink in which the drying speed of the ink is high, the bleeding is small, and the color development of printed matter is excellent. Regarding the recording method.

[0002]

2. Description of the Related Art The technical progress of an ink jet color printer for producing a color hard copy at a high speed has made it possible to obtain a clear image and excellent print quality. However, on the other hand, in order to further improve the print quality, saturation, appearance, and image, a recording material having higher characteristics has been required. In particular, due to improvements in printing speed, resolution, saturation, etc., more advanced properties such as quick drying of ink, high absorption capacity, control of dot diameter and bleeding are required for recording materials, and various types of recording are required. Sheets have been developed. JP-A-55-5183, JP-A-56-148585 and the like disclose that a receiving layer made of a porous inorganic pigment is provided on a substrate in order to improve ink absorption.

On the other hand, in recent years, ink jet printers have been used for printing wide-ranging advertisements, such as posters, from conventional printing of documents and the like. Inkjet printers are very easy to operate and, unlike printing such as plate making, are capable of printing in small quantities, so they can quickly print the required image in the required amount. In addition, for printing advertisements and the like, what is called a plotter or the like that can be printed in a wide width is usually used. Since these plotters are used for advertisements, images must be clearly visible even from a distance, and it is necessary to maintain clear images even in long-term posting. However, conventionally used ink jet inks are dye inks, which have been oxidized by ultraviolet rays, ozone, and the like in long-term display, causing a problem in that images are discolored and appearance is deteriorated. In order to solve such a problem, Japanese Patent Application Laid-Open No. Hei 9-157559 discloses that a pigment ink having higher light resistance than a dye ink is used as a plotter ink.
It is disclosed in JP-A-9-132740 and the like. However, dye inks "dye" the receiving layer with low molecular weight compounds
However, since the pigment ink develops the color by "laying" or "arranging" the pigment particles on the receiving layer, the characteristics required for the recording medium are different. In addition, pigments have a much larger molecular weight than dyes, so the fixing mechanism, such as bleeding control, is completely different from the low-molecular-level reaction of dyes. At present, sufficient characteristics cannot be obtained.

[0004] Further, also in label applications having a pressure-sensitive adhesive layer and a release paper on the back surface, in particular, storability of the recording portion is required, and therefore, a recording medium corresponding to pigment ink is required. However, in this method using a pigment ink, the recording density is hard to come out as compared with the method using a disperse dye, and conversely, if the ink is left on the recording medium surface in order to obtain the recording density,
There were drawbacks in that the image became thin or the background became dirty due to the rubbing of the recorded image surface. In addition, there is a disadvantage that when water is applied to the surface of the recorded image, the ink oozes out, that is, the so-called water resistance deteriorates. These problems are disadvantages caused by the fact that the pigment ink is not sufficiently fixed on the recording medium, and cannot be solved by a recording medium corresponding to a disperse dye type ink.

[0005] Regarding the water resistance of printing, when a disperse dye type ink is used, for example, Japanese Patent Laid-Open No. 9-188
No. 062, etc., a method of applying a waterproofing agent before and after printing, or as described in JP-A-55-66976, a recording medium using a volatile organic solvent as a solvent for ink. Although a method of spraying to provide water resistance has been proposed, for example, a method of applying a water-resistant agent complicates the mechanism, and if the liquid absorption capacity of the recording medium is not increased, so-called bleeding is performed. Bleeding occurs. On the other hand, according to this method, there is a problem that maintenance of the waterproofing agent is required together with the ink, and the running cost is increased.

As described above, there is an increasing demand for the use of pigment inks in industrial applications such as ink-jet label paper in which the preservability of the recorded portion is an absolute condition. As a characteristic of the pigment ink type, it is required that the ink is fixed on the surface of the recording medium at a point where the ink lands on the surface of the recording medium. As a fixing mechanism, a method is generally employed in which a cationic component is contained in the ink receiving layer and aggregated, noting that the dispersion of the pigment ink is anionic. The dye ink type requires a large amount of cationic components to fix the dye, whereas the pigment ink type has an excessive amount of cationic components that causes excessive coagulation on the surface, resulting in uneven ink distribution. Since a phenomenon called a ring causes a reduction in the recording density, excellent recording could not be obtained with a conventional recording medium for dye ink. Further, inkjet printers used in industrial applications tend to have higher printing speeds in order to increase processing speed. In printing with a high-speed inkjet printer, the inkjet paper is transported in the inkjet printer after the ink has not completely absorbed the ink after printing, and unabsorbed ink adheres to the feed rolls etc. in the transport mechanism, and the inkjet paper is not printed. Since the ink is transferred from the feed roll or the like to the printing portion and stains the unprinted portion, which is a phenomenon called so-called roll staining, and the recorded image is stained, excellent recording was not obtained with the conventional recording medium.

[0007]

SUMMARY OF THE INVENTION The present invention relates to an ink-jet recording system such as an ink-jet printer or a plotter using a pigment ink, which has an excellent ink-absorbing ability,
An object of the present invention is to provide an ink jet recording sheet which can print a high-quality image at a high speed, has a high print density, and has no bleeding. Further, the present invention is a recording material having excellent recording properties using a pigment type ink having particularly excellent printing weather resistance, and is particularly suitable for applications where printing water resistance or printing abrasion resistance is required, such as industrial use. Provided is a recording medium having a high ink fixing property and an excellent recording density.

[0008]

The present invention includes the following aspects. [1] An ink jet recording medium comprising an ink receiving layer containing an amorphous silica having an oil absorption of 250 ml / 100 g or more and a binder, and the ink receiving layer was further measured by a colloid titration method. Cation strength (cation equivalent per weight) is 4.5 m equivalent / g or more and 8 m
An ink jet recording medium containing a cationic resin having a high cation strength of not more than equivalent / g. [2] An ink jet recording medium comprising a support and an ink receiving layer containing amorphous silica having an oil absorption of 250 ml / 100 g or more and a binder, wherein the ink receiving layer was further measured by a colloid titration method. Cation strength (cation equivalent per weight) is 1.5 m equivalent / g or more and 4 m
An ink jet recording medium containing a low cation strength cationic resin having an equivalent weight / g or less and a high cation strength cationic resin having a cation strength of 4.5 m equivalent / g or more and 8 m equivalent / g or less. [3] The ink jet recording medium according to [2], wherein the low cation strength cationic resin is a polydiallyldimethylammonium salt. [4] The ink jet recording medium according to any one of [2] and [3], wherein the low cation strength cationic resin has a molecular weight of 30,000 or less.

[5] The amorphous silica has an average particle diameter of 4
μm or more and 15 μm or less [1] to
The inkjet recording material according to any one of [4]. [6] An ink jet recording method for performing recording by applying ink droplets containing a pigment as a coloring component to the ink jet recording medium according to any one of [1] to [5].

[0010] The ink jet recording method for pigment ink is as follows.
This is a recording method in which ink droplets are ejected to a receptor layer to form an image, similar to dye ink, and the difference in ink absorbency greatly affects print quality. As the amount of coating increased, the ink absorbency improved, but at the same time, the pigment component was taken in and the print density tended to decrease. On the other hand, when the coating amount was reduced to allow the pigment component to be present on the surface, the bleeding worsened, and the ink solvent was not sufficiently absorbed by the receiving layer, so that the pigment particles moved together with the solvent. Was uneven and the white portion of the receiving layer was exposed in the printed portion, resulting in a decrease in print density. Because dye molecules are very small in dye inks, the dye binds to the receiving layer and becomes colored as it moves with the solvent. Therefore, when the absorption capacity of the receiving layer is low, the print density tends to be improved, but such a phenomenon did not occur at all with the pigment ink. That is, the coloring mechanism of the pigment ink was completely different from that of the dye ink. In the recording method using the pigment ink, the printing density can be improved by uniformly “arranging” or “spreading” the pigment particles on the surface layer of the receiving layer. The properties to be achieved are that the pigment component is uniformly present in the surface layer of the receiving layer, and that the solvent of the ink is quickly absorbed into the receiving layer.

[0011]

DETAILED DESCRIPTION OF THE INVENTION In the present invention, amorphous silica having a high oil absorption is used in combination with a cationic resin having a high cation strength,
Preferably, a coating liquid is prepared by dispersing an amorphous silica having a high oil absorption in a cation resin-containing aqueous solution having a high cation strength to provide an ink jet recording medium having excellent ink absorbency, recording suitability, and recording surface appearance. provide. This is excellent in recording suitability with an ink containing a dye as a colorant. However, in the case of recording with an ink containing a pigment as a coloring agent, it is preferable to further include a cationic resin having a low cationic strength. As a result of intensive studies on the absorption and adsorption properties of the pigment ink in the receiving layer, in a preferred embodiment, the coloring and bleeding of the pigment ink are improved by including two or more types of the specific cationic resin in the receiving layer. It was found that the ink absorption speed was improved.

The ink receiving layer is made of JIS K-5101 which is porous, has high ink absorbency, and enables clear color development.
Amorphous finely-divided silica having an oil absorption of 250 ml / 100 g or more based on the description in above is contained. By using such amorphous finely divided silica, an ink jet recording sheet having good ink drying properties can be obtained. It is considered that the reason for this is that if the oil absorption of silica is 250 ml / 100 g or more, the ink absorption capacity of the coating layer increases because there are sufficient voids in the silica particles. Preferably 2
70 ml / 100 g or more, more preferably 290 ml / 100
g or more. If the oil absorption of silica is less than 250 ml / 100 g, the ink absorption capacity per unit volume of the coating layer becomes insufficient, and even if the coating amount is increased, the ink absorption speed does not increase and bleeding occurs. There is no upper limit to the oil absorption of silica, but it can be obtained up to about 400 ml / 100 g.

[0013] Such amorphous finely divided silica has poor dispersibility in water, and uses a conventional nonionic or cationic dispersant which is used in a cationic ink-jet paper coating layer coating material. When dispersed in water and then, non-dispersion of amorphous finely divided silica, problems such as aggregation occurs,
Good inkjet paper coating layer paint cannot be manufactured,
Ink-jet paper manufactured using such a paint has bleeding and roughened coating surface due to non-dispersion, aggregation, and the like of amorphous finely divided silica. Further, when an anionic dispersant is used, it reacts with a cationic resin used as an ink fixing agent to cause aggregation. As a dispersing agent for this amorphous finely divided silica, the cationic strength is 4.5 to 8 meq / g, preferably 5 to 8 meq / g, more preferably 5 to 7 meq / g. By using a cationic resin having a high cation strength as described above, good dispersion of amorphous fine powder silica can be achieved. In a preferred embodiment, a pigment having a high oil absorption is added to an aqueous solution in which a cationic resin having a high cationic strength is dissolved, and the pigment is dispersed. The timing of addition when using a cationic resin having a low cationic strength is not particularly limited.

The pigment used in the ink receiving layer of the present invention is preferably amorphous silica having an oil absorption of 250 ml / 100 g or more. Amorphous silica is a method of mixing high-purity silica sand with sodium silicate and sulfuric acid to form a silicate sol, a method of forming the silicate sol into a three-dimensional aggregate, temperature, ions, and secondary aggregates under the influence of a surfactant. It can be obtained by a method of stopping growth and sedimentation or a method of decomposing silicon tetrachloride.
By using these synthetic amorphous silica or the like for the ink receiving layer, a recording sheet having more excellent ink absorbability can be obtained.

The average particle size of the pigment contained in the ink receiving layer of the present invention is not particularly limited, but is about 1 to 20 μm, and the average particle diameter is preferably 4 μm to 15 μm, more preferably 6 μm to 15 μm. By using a pigment such as amorphous silica, a recording sheet having a higher print density can be obtained. When the average particle diameter is 4 μm or more, it is considered that the dots of the landed ink become large and the print density becomes higher. Average particle size of amorphous silica is 15
If it exceeds μm, the coated surface may be rough and the appearance may be deteriorated.

Amorphous silica having an oil absorption of 250 ml / 100 g or more, and a cationic resin having a low cation strength of preferably not less than 1.5 meq / g and not more than 4 meq / g as measured by a colloid titration method, A recording sheet excellent in color development and ink drying properties can be obtained by incorporating a cationic resin having a high cation strength of not less than 5.0 meq / g and not more than 8 meq / g. Colloid titration is a titration method that utilizes an ion association reaction between colloid particles. That is, a solution in which an ionic polymer having a known molecular structure is dissolved is defined as a prescribed solution,
This is a method for measuring the ionic strength (equivalent / g: the amount of ions per gram of a sample) of an unknown polymer sample having the opposite ionicity to the known sample ("Colloid titration method", by Chité, November 1966) 20th, see Nankodo). In the titration method, the cation strength of the cationic resin can be measured by using an anionic polymer for the prescribed liquid.

A low cation strength cationic resin having a cation strength of 1.5 meq / g or more and 4 meq / g or less and a cation strength of 5.0 meq / g or more and 8 meq / g or less as measured by the above-mentioned measuring method. It is not clear why the color development and ink drying property of the print are good in the ink jet recording using the pigment ink by using together with the cationic resin having a low cation strength, but it is speculated as follows. You.

The pigment in the ink is chemically ionic in order to be uniformly dispersed in the ink solution.
In particular, it is usually practiced to provide an anionic group such as a carboxylic acid, so that it can be ionically bonded to a cationic substance. When the cationic substance is a polymer, an aggregate of the polymer may be formed with a plurality of pigment particles. In particular, it is presumed that a polymer having a higher cation strength is more likely to undergo aggregation. The cationic resin conventionally used for an ink jet recording medium has a high cation strength. However, when only the cationic resin having a cation strength of more than 4 meq / g is contained in the receiving layer, when the pigment ink lands on the surface of the receiving layer, the pigment particles are combined with the cationic resin on the surface of the receiving layer and aggregated. It is considered that the pigment particles cannot uniformly cover the receiving layer, white spots occur partially, and the print density decreases. on the other hand,
When a cationic resin having a cationic strength of less than 1.5 meq / g is used, aggregation due to ionicity does not occur, so that the pigment component of the ink cannot be captured on the surface of the receiving layer, and therefore, bleeding may occur. Can be Therefore, in the present invention, in order to obtain the above-mentioned effects such as improvement of the coloring property of the pigment ink, a cationic resin having a cation strength of 1.5 meq / g to 4 meq / g, preferably 2.5 meq / g is used as the main cationic resin. To 4 meq / g of a low cation strength cationic resin.

The cationic resin used in the ink receiving layer of the present invention includes polyethyleneimine, polyvinylpyridine, polydialkylaminoethyl methacrylate,
Polydialkylaminoethyl acrylate, polydialkylaminoethyl methacrylamide, polydialkylaminoethyl acrylamide, polyepoxyamine, polyamideamine, dicyandiamide-formalin condensate,
Dicyandiamide polyalkyl-polyalkylenepolyamine condensate, diallyldimethylammonium polymer salt such as polydiallyldimethylammonium hydrochloride, polyvinylamine, polyallylamine, polyallylamine salt, polyvinylamine salt, poly (oxyethyl-1-)
Compounds such as methylene) amine salts, polyvinylbenzylamine salts, polyacrylamidopropylmethylamine salts, polydiallylamine salts, acrylamide / diallylamine salt copolymers, monoallylamine / diallylamine salt copolymers, polyaminedicyanic polymers, and the like; Modified products can be exemplified. Further, by using a polydiallyldimethylammonium salt such as polydiallyldimethylammonium hydrochloride as a cationic resin having a low cation strength, an ink jet recording sheet having more excellent coating strength can be obtained. Further, as the cationic resin having a high cationic strength, a polyoxypropyl quaternary ammonium salt is preferable.

In applications where the rubbing resistance of the recording is required, the specific cationic resin (particularly, a cationic resin having a low cation equivalent) preferably has a molecular weight of 30,000 or less. By setting the molecular weight of the cationic resin contained in the ink receiving layer to 30,000 or less, it is possible to obtain a recording medium having a higher recording density and excellent scratch resistance. The molecular weight is preferably 25,000 or less, more preferably 2
It is 1,000 or less, most preferably 20,000 or less. Although there is no particular lower limit, it may be about 1,000, but is preferably 2,000 or more. Although the cause is not necessarily clear, if the dispersed pigment in the pigment ink that has landed on the surface of the ink receiving layer is too agglomerated, the surface of the recording material that is not colored between the pigments remains and the recording density as a whole decreases. Further, since the color pigment component in the ink is less penetrated by the aggregation due to the aggregation, the color pigment component remaining on the surface is easily rubbed off. As a result, the recording portion is decolored by the rubbing. It is presumed that the molecular weight has an effect on the aggregation state. If the amount of the cationic resin is small, the effect of improving the printing water resistance and the scratch resistance may not be sufficient. On the other hand, if the amount of the cationic resin is too large, the printing density and the scratch resistance may be reduced. , The ink absorption capacity is reduced, and blurring of the recorded image, which is called bleeding, may occur.

The amount of the cationic resin having a low cation strength of 1.5 meq / g or more and 4 meq / g or less contained in the ink receiving layer of the present invention is 100 pigment / 100 g / g.
It is about 0.5 to 100 parts by weight, preferably 5 to 80 parts by weight, more preferably 10 to 50 parts by weight based on parts by weight. If the amount of the cationic resin is less than 0.5 part by weight, bleeding may occur. If the amount exceeds 100 parts by weight, the print density may be improved, but the drying property of the ink may be reduced. .
On the other hand, the cationic resin contained in the ink receiving layer of the present invention having a cation strength of 4.5 meq / g or more and 8 meq / g or less is compounded in an amount of 0.5 wt. Parts by weight to about 10 parts by weight, preferably 2 parts by weight to 7 parts by weight. If the amount of the cationic resin is less than 0.5 part by weight, poor dispersion of silica may occur. If the amount exceeds 10 parts by weight, aggregation of the pigment ink may occur and print density may decrease.

In the ink receiving layer, other pigments of the above-mentioned specific amorphous silica may be added in order to improve coating suitability, as long as the bleeding of the ink and the print density, which are the objects of the present invention, are not impaired. Other pigments that can be used in the ink receiving layer of the present invention include those having an oil absorption of 250
amorphous silica, colloidal silica less than ml / 100 g,
Inorganic pigments such as calcium carbonate, clay, calcined clay, diatomaceous earth, talc, aluminum oxide, magnesium aluminosilicate, magnesium carbonate, barium sulfate, zinc oxide, aluminum hydroxide, magnesium hydroxide, zeolite, urea-formalin resin filler, acrylonitrile Substances such as organic pigments such as plastic pigments are exemplified. These pigments can be used in combination of two or more as necessary.

Examples of the binder contained in the ink receiving layer of the present invention include polyvinyl alcohol, polyvinyl alcohol derivatives such as silyl-modified polyvinyl alcohol and cation-modified polyvinyl alcohol, proteins such as gelatin and casein, starch and oxidized starch. Derivatives, water-soluble polymer binders such as cellulose derivatives such as polyvinylpyrrolidone, hydroxyethylcellulose, hydroxypropylcellulose, and carboxymethylcellulose; conjugated diene-based polymers such as styrene-butadiene copolymer and methylmethacrylate-butadiene copolymer. Water-insoluble polymer binders such as coalescing latex, acrylic polymer latex such as polymer or copolymer of acrylic acid ester and methacrylic acid ester, and vinyl polymer latex such as vinyl acetate copolymer It can be used. One or more of these binders can be appropriately selected and used as needed.

The binder contained in the ink receiving layer of the present invention is preferably contained in an amount of 10 to 100 parts by weight based on 100 parts by weight of the pigment. If the content is less than 10 parts by weight, the strength of the coating film may be reduced due to insufficient adhesive strength of the binder. On the other hand, when the addition amount exceeds 100 parts by weight, the capillary may be blocked due to the increase of the binder component in the coating layer, and the drying property of the ink may be reduced. In addition, a pigment dispersant, an antifoaming agent, a viscosity modifier, a crosslinking agent, a fluorescent dye, a colorant, an antioxidant, an ultraviolet absorber and the like are appropriately used as additives according to production conditions and required performance.

As the support of the present invention, acid paper, neutral paper,
Papers such as coated paper and cast coated paper, resin films (including paper with resin laminated on the surface), synthetic papers (filling thermoplastic resin with fillers such as inorganic pigments, stretching and inorganic foaming Papers), transparent, translucent, white plastic films and films such as non-woven fabrics, cloths and their composites, metal foils, etc., and at least two or more selected from these. In combination, for example, a sheet-like substance processed for adhesion or decorated by printing or pasting may be used. The pulp material contained in the paper used as the support of the present invention includes red pine, black pine, spruce pine, fir pine, conifers such as cedar, beech,
It is appropriately selected and used from groundwood pulp, sulfite pulp, kraft pulp, semi-chemical pulp, chemical ground pulp, refiner ground pulp, and waste paper pulp mainly using hardwood such as birch and Shinoki.

The paper used as the support of the present invention may be made of clay, talc,
Contains inorganic pigments such as calcium carbonate, calcined kaolin, aluminum oxide, aluminum hydroxide, and titanium oxide, and organic pigments such as urea resin-based fine particles, and internally added rosin-based, alkyl ketene dimer, alkenyl succinic acid, etc. as additives A sizing agent, a sulfuric acid band, a fixing agent such as cationic starch, a polyacrylamide-based polymer, a paper strength enhancer such as starch, etc. are appropriately selected and internally added, and a base paper formed by a known paper machine is suitably used. . If necessary, rosin, petroleum resin, oxidized starch, acetylated starch, starch such as hydroxyethylated starch and derivatives thereof, polyvinyl alcohol and derivatives thereof, styrene, alkyd, polyamide, acrylic, olefin, maleic acid, The sizing treatment may be performed with a synthetic resin based on a polymer such as vinyl acetate or two or more copolymers, or a surface sizing agent such as a synthetic resin emulsion or wax based. In addition, in order to adjust the thickness, known equipment such as a machine calendar and a super calendar may be used as necessary.

As the resin film used for the support of the present invention, polyester resins and olefin resins which are thermoplastic resins can be used. As polyester resin,
Examples include polyethylene terephthalate, polybutylene terephthalate, and polycyclohexene terephthalate, and examples of the olefin resin include those made of polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, or those containing these as main components. it can. In addition, these thermoplastic resins are
A kind or two or more kinds can be appropriately selected and used, and polystyrene, an acrylate copolymer or the like can be mixed and used as another thermoplastic resin. A film formed by stretching these thermoplastic resins in the machine direction and / or the transverse direction may be used. In addition, a film may be formed by mixing inorganic fine powder in the thermoplastic resin, and the film may be subjected to, for example, uniaxial or biaxial stretching treatment to form a paper-like layer. In the present invention, using a multilayer film obtained by laminating a plurality of such films as a support,
For example, a paper-like layer provided on both sides or one side of a base material layer 2
A three-layer film or a three- to five-layer film in which a surface layer is formed on at least one surface of a paper-like layer may be used. What made a thermoplastic resin into a paper-like layer is generally known as synthetic paper. The opacity of such a film is not particularly limited in the present invention.

The method for providing the ink receiving layer on the support is not particularly limited, and a conventionally known method may be used.
It can be provided by a coating machine such as a bar coater, an air knife coater, a blade coater, a die coater, a curtain coater, a gravure coater, and a lip coater. The coating amount of the ink-receiving layer obtained in the present invention is determined by the final use, and need not be unnecessarily increased as long as the ink absorption, color development, and coating film strength are satisfied.
４０40 g / m ^2, preferably 8-30 g / m ² . If the ink receiving layer is less than 5 g / m ² , the ink absorption capacity is often insufficient, causing the image to flow out, drying slowly, and the ink adhering to the paper discharge roll of the printer and becoming dirty. However, 40 g / m
^{When an} ink receiving layer exceeding ² is provided, the strength of the ink receiving layer is weakened, and a problem such as clogging of a head nozzle may be caused by the peeled ink receiving layer,
Further, the cost is high.

The ink receiving layer of the present invention may be a single layer or a multilayer. Corona treatment or various anchor coating treatments can be performed on the support for the purpose of increasing the adhesion between the support and the ink receiving layer. The ink receiving layer can be formed by simultaneously forming a single layer or two or more layers, or by transferring a layer applied in another step to form an ink receiving layer on a support. The sheet provided with the ink receiving layer on the support can be used as it is as the recording sheet of the present invention. For example, the sheet can be treated with a super calender, a gloss calender or the like to impart surface smoothness. . In addition, an adhesive layer is provided on the back surface and processed as an adhesive, or a support is attached to each other to be processed as a double-sided recordable recording medium, and a film is laminated on the ink receiving layer surface after printing, and Known techniques such as protection of the recording surface can be applied.

The recording method applied to the recording paper of the present invention is an ink jet recording method using an ink liquid having a pigment as a coloring component. The recording liquid is a recording liquid in which an organic or inorganic pigment particle component is dispersed in an aqueous solution or an organic solution containing water, isopropyl alcohol, or the like using a dispersant or the like. Examples of the organic pigment include pigments such as azo, phthalocyanine, perlin, isoindolinone, imidazolone, pyranthrone, and thioindigo pigments.Examples of inorganic pigments include carbon black, graphite, and synthetic iron oxide yellow. , Transparent Bengal, Titanium Yellow, Molybdate Orange, Cuprous Oxide, Cobalt Blue, Ultramarine, CI Pigment Yellow (Yellow Ink), CI Pigment Blue (Cyan Ink), CI Pigme
Pigments such as nt Red (magenta ink) can be exemplified. As the dispersant, various surfactants, low molecular weight dispersant,
A resin-based dispersant having a hydrophilic functional group and a hydrophobic functional group is used. Further, an aqueous resin can be added for the purpose of adjusting the viscosity of the ink. The pigment and the dispersant are blended in a solution, crushed into fine dispersed particles using a disperser such as a paint shaker or a sand mill, and the coarse particles are filtered with a filter having a pore size of 1.0 μm or less to obtain a pigment ink. That is usually done. The solid content concentration in the pigment ink is not particularly limited, but is 0.5 to 30% by weight.

[0031]

EXAMPLES The present invention will be described more specifically with reference to the following examples, but it should be understood that the present invention is not limited by these examples. In the following, parts and% all indicate parts by weight and% by weight. Example 1 Wood pulp (LBKP: freeness 500 ml CSF) 10
0 parts, calcined kaolin (trade name: Ansilex, manufactured by Engelhard Minerals) 10 parts, commercial sizing agent 0.05
Using a papermaking material consisting of 1.5 parts by weight, a sulfuric acid band of 1.5 parts, a wet paper strength agent of 0.5 parts, and starch of 0.75 parts, a high quality paper having a basis weight of 80 g / m ² was produced by a fourdrinier paper machine. The Stechig sizing degree of this high quality paper was 6 seconds. All the paper base materials used in Examples and Comparative Examples of the present invention used this high-quality paper. One side of the high-quality paper produced by the above method was coated with paint-1 at an absolute dry weight of 8 g / m ² and then dried to obtain an ink jet recording sheet. Amorphous silica was dispersed in a liquid containing a cation resin having a cation equivalent of 6.2 meq / g, and other components were added.

Paint-1 amorphous silica (average particle diameter 4.3 μm, oil absorption 260 m
1/100 g; 100 parts of Fine Seal X-45 (trade name, manufactured by Tokuyama), cationic resin (cation strength: 2.9)
m equivalent / g, substance name: dicyandiamide / polyethyleneamine; trade name: Neofix, manufactured by Nichika Chemical Co., Ltd., 20 parts, cationic resin (cation strength: 6.2 m equivalent / g, molecular weight: 1)
00,000, 5 parts of diallyldimethylammonium hydrochloride (trade name, manufactured by Unisense, manufactured by Senka), and 60 parts of binder (completely saponified polyvinyl alcohol; trade name, PVA117, manufactured by Kuraray).

Example 2 One side of the high-quality paper used in Example 1 was coated with paint-2 in an absolutely dry amount of 2%.
After coating at 5 g / m ² , drying was performed to obtain an inkjet recording sheet. Amorphous silica was dispersed in a liquid containing a cationic resin having a cationic strength of 5.7 equivalents / g, and other components were added. Paint-2 amorphous silica (average particle diameter 3.5 μm, oil absorption 310 m
l / 100 g; trade name: Silojet P-405, manufactured by Grace Devison) 100 parts, cationic resin (cation equivalent: 3.4 m equivalent / g, substance: dicyandiamide / formaldehyde) 50 parts, cationic resin (cation strength: 5.0)
7 meq / g, substance name: polyoxypropyl quaternary ammonium salt, trade name: Saftomer, manufactured by Mitsubishi Chemical Corporation; 8 parts, binder (partially saponified polyvinyl alcohol; trade name: PVA42)
0, Kuraray) 30 parts.

Example 3 Paint-3 was applied to one side of the high-quality paper used in Example 1 in an absolutely dry amount.
After coating at 5 g / m ² , drying was performed to obtain an inkjet recording sheet. The oil absorption of the mixed-type amorphous silica of Paint-3 was 258 ml / 100 g. Cation strength5.
Oil containing 31 m equivalent / g of cationic resin
0 ml / 100 g of silica was dispersed, and oil absorption 180
ml / 100 g of silica was dispersed and other components were added. Paint-3 amorphous silica (average particle diameter 7.5 μm, oil absorption 310 m
1/100 g; trade name: Silojet P-412, manufactured by Grace Devison) 60 parts, amorphous silica (average particle size: 1)
2 μm, oil absorption: 180 ml / 100 g; trade name: Sylysia 470, manufactured by Fuji Silysia) 40 parts, cationic resin (cation equivalent: 3.5 m equivalent / g, molecular weight: 4,000,
Substance name diallyldimethylammonium hydrochloride) 35 parts,
2 parts of cationic resin (cation strength: 5.1 meq / g, molecular weight: 20,000, substance name: diallyldimethylammonium hydrochloride; manufactured by Senka), 40 parts of silanol-modified polyvinyl alcohol (trade name: R-1130, manufactured by Kuraray), acetic acid Vinyl-ethylene latex (Sumikaflex S
-473, manufactured by Sumitomo Chemical) 5 parts.

Example 4 Synthetic paper having a three-layer structure containing polypropylene and an inorganic pigment and having a central substrate layer and paper-like layers on both front and back surfaces (trade name: Yupo FPG-110, manufactured by Oji Oil Chemical Synthetic Paper, thickness: 110 μm)
After applying 15 g / m ² of paint-3 on one side in an absolutely dry amount, drying was performed to obtain an ink jet recording sheet.

Comparative Example 1 The cationic resin of Example 1 (cation strength: 2.9 meq / g, substance name: dicyandiamide / polyethyleneamine;
20 parts of Neofix, manufactured by Nikka Chemical Co., Ltd. and a cationic resin (cation strength: 6.2 meq / g, molecular weight: 100,
000, substance name diallyldimethylammonium hydrochloride,
5 parts PAA-
An ink jet recording sheet was obtained in the same manner as in Example 1, except that HCL-10L (cation strength: 9.2 meq / g, molecular weight: 80,000, substance name: polyallylamine hydrochloride, manufactured by Nitto Boshoku) was changed to 25 parts. .

Comparative Example 2 The cationic resin of Example 1 (cation strength: 6.2 meq /
g, molecular weight 100,000, substance name diallyldimethylammonium hydrochloride, trade name Unisense, manufactured by SENKA) 5 parts of cationic resin (cation strength 4.0 m equivalent / g, substance name dicyandiamide / polyethylene polyamine; manufactured by SENKA) 5 parts Was obtained in the same manner as in Example 1 except for changing to.

Example 5 The cationic resin of Example 3 (cation equivalent: 3.5 meq /
g, molecular weight of 4,000, substance name diallyldimethylammonium hydrochloride) was changed to trade name CM-318 (cation strength: 0.5 m equivalent / g, substance name: cation-modified polyvinyl alcohol, manufactured by Kuraray). Similarly, an ink jet recording sheet was obtained. Comparative Example 3 Inkjet printing was performed in the same manner as in Example 1 except that the amorphous silica having an oil absorption of 260 ml / 100 g was replaced with amorphous silica (average particle diameter: 12 μm, oil absorption: 180 ml / 100 g; trade name: Sylysia 470, manufactured by Fuji Silysia). A recording sheet was obtained.

Table 1 shows the evaluation results of the obtained coated sheet samples. The cation strength (cation equivalent per g) of the cationic resin is 0.4 ml of a 0.4 g / l cation resin solution.
, Add 2 drops of toluidine blue indicator, titrate with N / 400 solution of polyvinyl potassium sulfate (PVSK), read the titer at which the solution turned from blue to reddish purple, and calculate the cation strength of the cation resin from the following formula Was. Cation strength (m equivalent / g) = [{1/400 (equivalent / l) x PVSK titer (ml) x PVSK factor｝ ÷ {0.4 (g / l) x 10 (ml)}] x 1000 The PVSK factor was 1.108. The suitability for inkjet recording was evaluated by the following method.

(1) Print density (color development): Using an ink jet plotter (NOVA JET PRO, GO Ink ENCAD), print density of 100% of black, 100% of yellow, 100% of magenta, and 100% of cyan are measured. evaluated. Each ink is an ink containing a pigment as a color-forming component, the black ink has carbon black as a color-forming component, and the solvent is composed of 81.8% of water and 18.2% of diethylene glycol. The magenta ink has quinacridone magenta (CIPigment Red 122) as a coloring component, and the solvent is composed of 84.7% of water and 15.3% of diethylene glycol. ◎ ・ ・ ・ Excellent print density ○ ・ ・ ・ Good print density △ ・ ・ ・ Slightly low print density × ・ ・ ・ Extremely low print density

(2) Bleeding: The ink jet plotter (NOVA JET PRO, GO Ink ENC)
AD), 100% cyan and 100% magenta
Was subjected to a sensory evaluation of the bleeding of the 200% multicolor printed portion. ◎ ・ ・ ・ Excellent with no bleeding ○ ・ ・ ・ Good with almost no bleeding △ ・ ・ ・ Bleeding is recognized × ・ ・ ・ Poor and practically problematic

(3) Surface strength (coating film strength) was evaluated by sensory evaluation by performing a cellophane tape (Nichiban) peel test. ◎ ・ ・ ・ Excellent coating strength ○ ・ ・ ・ Good coating strength △ ・ ・ ・ Slightly poor coating strength

(4) Appearance: The surface of the coating layer was visually observed and evaluated organoleptically. ◎ ・ ・ ・ Appearance of coating layer surface is very smooth and very good ○ ・ ・ ・ Appearance is smooth and good × ・ ・ ・ Coating layer surface is rough

[0044]

[Table 1]

As is clear from Table 1, the ink jet recording sheets obtained in the examples have the following properties:
Excellent in both bleeding and coating strength. On the other hand, the ink jet recording sheet obtained by the comparative example did not show good results in terms of print color development, bleeding, and coating film strength.

[0046]

The ink jet recording sheet of the present invention is excellent as ink jet recording paper for pigment inks in color development of printing, bleeding and coating strength.

Claims (5)

[Claims] 1. An ink jet recording medium comprising a support and an ink receiving layer containing amorphous silica having an oil absorption of 250 ml / 100 g or more and a binder, wherein the ink receiving layer is further subjected to a colloid titration method. An ink jet recording medium containing a high cation strength cationic resin having a measured cation strength of 4.5 meq / g or more and 8 meq / g or less. 2. An ink jet recording medium in which the ink receiving layer further contains a low cation strength cationic resin having a cation strength of 1.5 to 4 meq / g as measured by a colloid titration method. 3. The ink jet recording medium according to claim 2, wherein said low cation strength cationic resin is a polydiallyldimethylammonium salt. 4. The ink jet recording medium according to claim 2, wherein the low cation strength cationic resin has a molecular weight of 30,000 or less. 5. An ink jet recording method for performing recording by applying ink droplets containing a pigment as a color forming component to the ink jet recording medium according to claim 1.