JP2001219642A - Highly glossy ink jet recording paper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a highly glossy ink jet recording paper, excellent in ink absorbing property, capable of distinct printing without oozing substantially, prominent in fade resistance, excellent in the smoothness and lustrous property of the surface of the same and capable of contriving the reduction of a cost compared with a case wherein silica is employed as a pigment. SOLUTION: An ink absorbing pre-coat layer, whose principal constituent is the pigment, is provided on a substrate while an ink receptor layer consisting of an acrylic cation base water absorbing and releasing urethane resin is laminated on the pre-coat layer sequentially.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high gloss ink jet recording paper.

[0002]

2. Description of the Related Art An ink jet recording system is widely used because it has an advantage that full color printing is easy and noise during recording is small.

[0003] Ink-jet recording papers for this purpose are required to have no bleeding, excellent ink absorbency, excellent smoothness and gloss on the paper surface, high print density, high print water resistance, and the like.

In general, ink jet recording paper is prepared by coating a base paper with a coating liquid containing a pigment and a binder as main components, using a blade coater, an air knife coater, a roll coater, a bar coater, a gravure coater, a rod blade coater, a lip coater, a curtain coater, It is obtained by coating using a die coater or the like.

[0005] As the pigment used here, amorphous silica or synthetic silica, clay, calcium carbonate and the like are used. It is preferable to use silica having a large specific surface area in that the ink absorbency is increased.

[0006]

However, conventional ink jet recording papers do not always have sufficient ink absorbency and are not satisfactory in preventing bleeding.

Accordingly, the main object of the present invention is to provide excellent ink absorption, clear printing with almost no bleeding, extremely excellent fading resistance, and excellent recording paper surface smoothness and gloss. Another object of the present invention is to provide a high-gloss ink jet recording paper which can reduce the cost as compared with the case where silica is used as a pigment.

[0008]

Means for Solving the Problems The inventors of the present invention have succeeded in forming an ink-absorbing pre-coat layer containing a pigment as a main component and an ink-receiving layer made of an acrylic cation-based water-absorbing and releasing resin on a base paper in order. It has been found that the ink exhibits excellent ink absorbency, enables clear printing with almost no bleeding, and is extremely excellent in fading resistance. Such advantages are particularly remarkable when the proportion of light calcium carbonate in the pigment is large. However, when this type of coating liquid is applied by the above-described coating method, the smoothness and glossiness of the recording paper surface are not good. It was also found. The present invention that has solved the above problems is as follows.

<Invention according to claim 1> A base paper is provided with an ink-absorbing precoat layer containing a pigment as a main component, and a transparent or semi-transparent resin containing an acrylic cation-based water-absorbing and releasing resin as a main component is provided on the ink-absorbing precoat layer. High gloss ink jet recording paper characterized by sequentially laminating transparent ink receiving layers.

(Function and Effect) A. Unlike the highly water-absorbent resin represented by general acrylic resin, the acrylic cation-based water-absorbent resin is transparent or translucent, exhibits a water absorption of about 50 to 100% of its own weight, and absorbs water over time. Since the ink has a property of releasing, when ink is received, the ink component is left between the resin pores on the surface of the ink receiving layer, and only the water in the ink is passed through the pores to form the ink absorbing precoat layer and the base paper. Infiltrate Therefore, clear printing is obtained with excellent ink absorbency.

<Invention according to claim 2> The pigment is light calcium carbonate having a specific surface area of 50 to 130 g / m ² , and is contained in the ink-absorbing precoat layer in an amount of 70% by weight or more, and the light calcium carbonate is 100% by weight. The high gloss ink jet recording paper according to claim 1, wherein the binder contains 5 to 50 parts by weight of the binder.

(Function and Effect) The specific surface area of general light calcium carbonate is 0.5 m ²
/ G to 10 m ² / g or less. However, the specific surface area of the light calcium carbonate used in the present invention is 50 to 130 m.
² / g is very high. As a result, the ink absorbing layer penetrates into the ink absorbing precoat layer through the resin pores on the surface portion of the ink receiving layer, has extremely excellent water absorbability, and prevents bleeding due to the diffusion of water. In order to sufficiently exhibit this effect, it is preferable that the light calcium carbonate according to the present invention is contained in the pigment in an amount of 70% by weight or more.

C. Since the light calcium carbonate of the present invention is excellent in binding property, the amount of the binder used is 5 to 50 parts by weight, preferably 20 to 30 parts by weight, based on 100 parts by weight of the pigment, because of the possibility of powder falling. As a result, the amount of the binder used is not excessive, and as a result, the resistance to fading due to the binder is increased.

<Invention according to claim 3> The high gloss ink jet recording paper according to claim 1 or 2, wherein the ink absorbing precoat layer is formed by a cast coating method.

(Function and Effect) In the present invention, the above A
The following advantages are provided in addition to -C.

D. Since a large number of pores are formed in the ink-absorbing precoat layer, the smoothness and gloss of the surface of the recording paper are not good in the ordinary coating method. Therefore, according to the present invention, when the ink-absorbing precoat layer is applied by a cast coating method, higher smoothness and glossiness of the recording paper surface can be obtained as compared with ordinary coated paper,
Moreover, it can be obtained at low cost.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, an ink-absorbing precoat layer containing a pigment as a main component is provided on a base paper, and an ink-receiving layer made of an acrylic cation-based water-absorbing and releasing resin is sequentially laminated on the ink-absorbing precoat layer. This is a high gloss ink jet recording paper characterized in that:

Hereinafter, the present invention will be described in detail. First, the acrylic cationic water-absorbing and desorbing resin used in the present invention is a water-dispersed acrylate copolymer.
-Polymerization of acrylic monomers such as ethylhexyl acrylate, acrylic acid and β-hydroxyethyl acrylate. By changing the ester used for polymerization,
A hard and soft acrylic ester copolymer can be easily obtained.

The acrylic cationic water-absorbing and dewatering resin used in the present invention has good miscibility with various pigments as compared with the conventional high water-absorbing resin represented by polyacrylic acid. Shows less increase in viscosity and strong adhesion to pigments. Particularly when a calcium carbonate or silica pigment is used, strong adhesiveness is exhibited. Furthermore, it has very good compatibility with aqueous compositions such as water-soluble polymers and cationic polymers, and has very little water-thickening and extremely excellent water resistance.

Further, the characteristic feature of the acrylic cationic water-absorbing and releasing resin used in the present invention is exhibited when used in combination with an ink-absorbing precoat layer containing a pigment as a main component.
That is, the compatibility with the above-mentioned ink-absorbing precoat layer is improved, and as a result, a strong adhesive strength is obtained, the surface strength of the ink-receiving layer is improved, and an ink-receiving layer having extremely excellent water resistance is obtained.

Conventionally, an ink jet recording sheet using both a pigment and an adhesive has a water-soluble polymer adhesive such as polyvinyl alcohol (hereinafter referred to as PVA), modified PVA.
A, hydroxyethylcellulose, CMC, cellulose derivatives, starch, cationic starch and the like have been used. When only these water-soluble polymers were used as the adhesive, not only the surface strength as in the present invention was not obtained, but also the water resistance after printing was poor.

When an ordinary aqueous emulsion type polymer latex, for example, SBR, polyvinyl acetate, acrylic resin, styrene-acryl copolymer, ethylene-vinyl acetate polymer, polyvinyl butyral is used as an adhesive, The dry film, that is, the ink receiving layer has water resistance, but on the other hand, there is a disadvantage that the absorbability of the aqueous ink is deteriorated, and the dry film causes a whitening phenomenon peculiar to latex and the resolution ability is reduced. is there.

When the acrylic cationic water-absorbing and releasing resin of the present invention is used for the ink receiving layer of an ink jet recording sheet, the difficulties inherent in latex are solved, and the water resistance is extremely improved, which is not seen in the conventional latex system. The effect and the effect of improving the absorptivity of the aqueous ink are exhibited.

In the present invention, the pigment has a specific surface area of 50 to 130 m ² / g, more preferably 70 to 90 m ² / g.
Use light calcium carbonate.

In the present invention, it is necessary to include a pigment in the ink absorbing precoat layer, and to use the light calcium carbonate as a pigment in the pigment in an amount of 70% by weight or more, especially when synthetic silica is not used. In order to improve the ink absorbency, it is preferable to use 90% by weight or more.

As the content of the light calcium carbonate increases, the dot density increases, the sharpness improves, and the roundness also improves. In this case, an excellent recorded image can be obtained. But 70% by weight
If the content is less than 1, the density of the dots may be insufficient and the reproducibility of the color from the original may be poor.

In the present invention, the pigment which can be used in combination with the above-mentioned light calcium carbonate is preferably synthetic silica. When synthetic silica, especially synthetic silica having a specific surface area of 150 m ² / g or more, is used, the ink absorbency can be improved. However, other pigments can also be used, and pigments used for ordinary paper coating can be appropriately selected and used. As the pigment, for example, kaolin,
Inorganic pigments such as clay, talc, ordinary light calcium carbonate, heavy calcium carbonate, aluminum hydroxide, titanium dioxide, and satin white, and organic pigments such as plastic pigment can also be used. When an organic pigment is used, its content is preferably set to 6% by weight or less in the pigment. The pigment can be easily contained in the ink absorbing precoat layer by mixing and dispersing the pigment in a coating liquid by a known method.

In the present invention, a binder is added to the coating liquid in order to impart a binding property to the base paper to the pigment and uniformly form the ink absorbing precoat layer. Examples of the binder include oxidized starch, starches such as esterified starch, carboxymethylcellulose, cellulose derivatives such as hydroxyethylcellulose, polyvinyl alcohol and derivatives thereof, casein, gelatin, soy protein, styrene-maleic acid resin and derivatives thereof, and styrene.・ Conjugated diene polymer latex such as butadiene copolymer, methyl methacrylate butadiene copolymer, acrylic polymer latex such as acrylate and methacrylate polymer or copolymer, ethylene vinyl acetate copolymer, etc. And vinyl acetate-based emulsions or mixtures of two or more of these.

The amount of binder used is 100 pigments.
5 to 50 parts by weight, more preferably 20 to 3 parts by weight based on parts by weight
8 parts by weight. In addition, the coating liquid, if necessary, a pigment dispersant, a water retention agent, a thickener, a foaming agent, a release agent, a preservative,
Color pigments, water-proofing agents, wetting agents, fluorescent dyes, ultraviolet absorbers and the like can be added.

In the present invention, it is preferable that the ink receiving layer contains a cationic polymer in order to improve the water resistance of the recorded image. Such a cationic polymer electrolyte reacts with a water-soluble direct pigment in an ink to be used or a —SO ₄ Na group, a —SO ₄ H group, a —NH ₄ group, or the like in an acid dye molecule to be insoluble in water. This prevents the dye in the ink from dissolving in water and improves the water resistance of the recorded image.

The above cationic polymer electrolyte includes:
For example, polyvinylbenzyltrimethylammonium halide, boridiacryldimethylammonium halide, polydimethylaminoethyl methacrylate hydrochloride, polyethyleneimine, dicyandiamide formalin condensate, epichlorohydrin-modified polyalkylamine,
Examples thereof include polyvinyl pyridinium halide, polyethyleneimine quaternary ammonium salts, and polyamine.

The coating amount of the coating solution prepared as described above is 5 to 50 g / m ^{2 in} terms of solid content per one side of the base paper.
However, it is particularly preferably 10 to 30 g / m ² . The pigment is preferably 3 to 30 g / m ² .

In the present invention, the ink absorbing precoat layer is provided on the base paper by the cast coating method. This cast coating method is the same as the method for producing ordinary cast coated paper. That is, in the present invention, a wet cast coating method of finishing the paper surface in a glossy state by pressing a heated drum having a mirror-finished cylindrical outer surface to the ink absorbing precoat layer in a wet state provided on the base paper surface, After the ink absorbing precoat layer in a wet state provided on the base paper surface is in a gel state, a gelled cast coating method in which a heated drum having a mirror-finished cylindrical outer surface is pressed against to finish the paper surface in a glossy state, And after drying the wet ink absorbing precoat layer provided on the base paper surface, the coating layer plasticized by applying a rewet liquid,
An ink-absorbing precoat layer is provided by any one of rewet cast coating methods in which a heated drum having a mirror-finished cylindrical outer surface is brought into pressure contact with the surface to make the surface of the ink-absorbing precoat layer glossy.

The coating amount is 0.5 to 50 as a dry film thickness.
μm. In order to obtain a higher gloss ink jet recording paper, the acrylic cationic water-absorbing and releasing resin according to the present invention may be applied by the same cast coating method as described above.

The base paper used in the present invention is not particularly limited, and may be appropriately selected from known papers such as neutral paper mainly composed of wood pulp and recycled paper which are generally used for ink jet recording paper. Can be used.

Recycled paper is particularly preferred because of its high opacity and excellent prevention of strike-through when compared at the same basis weight.

When synthetic silica is used as the pigment, it is desirable to include a cationic agent having an aluminum group in the coating liquid in order to adjust the viscosity and obtain a high image density.

As the cationic agent having an aluminum group, an organic aluminum compound, an inorganic salt of aluminum, an aluminum oxide, an aluminum compound such as aluminum hydroxide, or the like, or the above compound is electrically or otherwise applied to the surface of the above-mentioned pigment. Or the one treated by reacting with the hydroxyl group on the surface can be used.

The organoaluminum compound may be any of the conventionally known organoaluminum compounds, but preferred are aluminum compounds such as aluminum alcoholate compounds, aluminum chelate compounds and cyclic aluminum oligomers. It has reactivity with the adsorption component and the surface functional group present on the surface.

Preferred specific examples of the organoaluminum compound include, for example, aluminum alcoholate compounds such as aluminum ethylate, aluminum isopropylate, monosec-tetoxyaluminum diisopropylate, and aluminum sec-butylate: ethyl acetoacetate aluminum Aluminum chelate compounds such as diisopropylate, aluminum tris (ethyl acetoacetate), alkyl acetoacetate aluminum diisopropylate, aluminum monoacetylacetonate bis (ethyl acetoacetate), aluminum tris (acetylacetonate): cyclic aluminum oxide isopropylate And cyclic aluminum oligomers such as cyclic aluminum oxide stearate. Alternatively, aluminum stearate or laurate may be used.

Examples of the inorganic salts of aluminum include chlorides, sulfates, nitrates, ammonium salts, acetates, carbonates, and nitrates, as well as aluminates such as sodium aluminate and potassium aluminate, and alum. And these may also have water of crystallization.

Aluminum oxide refers to aluminum hydroxide obtained by subjecting bauxite which is a natural mineral to hot caustic soda treatment industrially or aluminum hydroxide obtained by spark discharge of metal aluminum pellets in pure water. It is obtained by calcining, and its production method is conventionally known, and various crystal systems (α-form, γ-form, σ-form, η-form,
(θ-type) and those having various particle diameters, high density and specific surface area are commercially available, and the present invention includes all of these aluminas.

[0043]

EXAMPLES (Example 1) Freeness as raw pulp
(CSF) 370 ml of LBKP 85 parts (hereinafter “parts”)
Means parts by weight and "%" means% by weight
You. ), Freeness (CSF) 440ml NBKP1
80 g / m2 of rice tsubo obtained by mixing 5 parts ^TwoThe following paper
Ink absorption pre-coat layer coating solution is mirror-finished in wet condition
Pressed to a drum having a cylindrical outer surface heated to 80 ° C
To make the surface of the ink absorbing precoat layer glossy
8g / m coating amount by wet cast coating method
^TwoCoated and dried so that Air knife coater
By applying a cationic water-absorbing and releasing resin,
A light receiving layer was formed.

As the coating liquid for the ink absorbing precoat layer,
Light calcium carbonate as pigment (BET specific surface area 80m
² / g, product name: 70 parts of jet coat 30), and synthetic amorphous silica (Mizuka Seal P-78A: manufactured by Mizusawa Chemical Co., Ltd.)
30 parts, polyvinyl alcohol (r-
1130: Kuraray Co., Ltd., solid content concentration 10%) 400 parts,
Against a cationic dye fixing agent (Sumireze Resin 1
001: Sumitomo Chemical Industries, solid content concentration 30%)
And a solid content of 4 parts by weight of alkyl acetoacetate aluminum diisopropylate (aluminum chelate M: manufactured by Kawaken Fine Chemical Co., Ltd.).

IJC-9C (manufactured by YAS Corporation) was used as the aklelu cationic water-absorbing and releasing resin.

(Other Examples, Comparative Examples and Reference Examples) The amounts of the light calcium carbonate, the binder and the synthetic amorphous silica used in Example 1 were changed, and other light calcium carbonate (TP) was used as a pigment. -121, manufactured by Okutama Industry Co., Ltd.) to obtain various examples of high gloss ink jet recording paper. Furthermore, the case where alkyl acetoacetate aluminum diisopropylate as a cationic agent having an aluminum group was not added was also examined. In addition, super-calendered products were also examined.

<Evaluation Method> The recording density, ink absorbency, glossiness, and bleeding of the high gloss ink jet recording papers obtained in Examples and Comparative Examples were evaluated by the following methods. Table 1 shows the results.

[0048]

[Table 1]

Note: * 1: Light calcium carbonate (TP-
* 2: Super calender treatment without using the wet cast coating method * 3: Polyacrylic acid-based water-absorbent resin is used in place of the acrylic cation-based water-absorbent resin.

[Recording density]: Solid recording of four colors (black, cyan, magenta, yellow) using a Canon full-color printer BJF600 at a temperature of 20 ° C. and a humidity of 20% (size: 3.0 cm × 3.0 cm). 0cm)
The recording density of the recorded portion was measured with a Macbeth densitometer (RD915) in a state where the ink permeation was stable 30 minutes after printing. The table shows the total of the measured values of the four colors, and 3.3 or more was regarded as good.

[Ink absorption]: Yellow, magenta,
Each single color of cyan is imprinted, and high quality paper is stuck on the printed surface printed every 5 seconds immediately after printing, and it is observed whether or not the ink is transferred to the high quality paper. (○: less than 10 seconds, Δ: 10
(Less than 30 seconds, x: 30 seconds or more) An ink drying time of less than 10 seconds is excellent in ink absorbency.
[Glossiness of print portion (shine)]: The glossiness of the print portion is visually observed from a lateral angle of 20 ° with respect to the print portion, and is 4 as follows.
Dan evaluation. ：: There is the same level of shine as a silver halide color photograph. ：: Inferior to color photograph, but with high shine. Δ: comparable to coated paper print product. X: comparable to general PPC.

"Bleed": Canon full color printer B
Using JF600 at a temperature of 20 ° C. and a humidity of 20%, red, green, and purple, which are formed by superimposed colors of three primary colors (cyan, magenta, and yellow inks), are each alternately solid-recorded (3.0 cm in size). × 3.0 cm) was continuously recorded, and the degree of occurrence of bleeding between adjacent ink jet inks on one side or the other was evaluated in a state where the ink permeation was stable 30 minutes after printing. Evaluation A- No bleeding of ink. Evaluation B-Slight bleeding of the ink was observed. Evaluation C- There is a clear bleeding of the ink. Precipitated calcium carbonate versus specific surface area and use is 50~130m ² / g of use and over般軽calcium carbonate in precipitated calcium carbonate <Consideration> - specific surface area of 50~130m ² / g, the synthetic amorphous The specific surface area comparable to porous silica and the fact that calcium carbonate has cationic properties improve the fixability of the ink (anion). Calcium carbonate, which has a small specific surface area, has insufficient adsorbing power for the dye of the inkjet ink, and the dye penetrates deeply from the surface of the ink receiving layer together with the water in the inkjet ink. I can't. The use gives a glossy feeling, but the ink-jet ink is inferior in absorbency and drying property. In addition, poor drying and fixing of ink may occur. The reason why the use amount of the light calcium carbonate having a specific surface area of 50 to 130 m ² / g is 70% by weight or more, particularly 90% by weight or more. In order to obtain the setting property, it is preferable that the particles are porous and are in the form of secondary aggregates of fine particles. Specific surface area is 50 to 130
The use of light calcium carbonate of m ² / g shows high ink receptivity. If the amount used is less than 70% by weight, the dispersibility and stability at the time of preparing the coating liquid may deteriorate,
Operability deteriorates extremely. In particular, the stability in the preparation of the paint was obtained at 90% by weight or more. The reason why the binder is contained in an amount of 5 to 50 parts by weight based on 100 parts by weight of the pigment is to prevent the powder from falling off the pigment and to ensure high ink receptivity. That is, if the amount is too large, the formation of the porous surface is hindered, and if the amount is too small, the fixation of the pigment is deteriorated, which causes problems such as powder dropping. -Synthetic silica is excellent in ink absorption and drying properties, and exhibits an effect of preventing print strikethrough due to the opacity of the pigment. Excessive content of synthetic silica impairs the appearance of gloss. In addition, although calcium carbonate is excellent in the fixability, color developability and glossiness of the ink-jet ink, it is inferior in ink drying property and may cause a problem during high-speed printing. It is also intended to compensate. The reason why the content of the synthetic silica is less than 30% by weight is to ensure the maintenance of the color development and gloss of the ink. When containing a cationic agent having an aluminum group,
The ink fixability and the dispersion stability effect at the time of adjusting the coating liquid are extremely enhanced.・ Comparison between cast coating method and other coating methods Coated paper for ink jet manufactured by the conventional coating and drying methods mainly has low smoothness and gloss on the coated surface and unclear dot edges. Met. This is attributable to the addition of amorphous silica, fine silica powder, or the like as a pigment component to the ink jet recording coating liquid in order to increase the ink absorption speed and absorption amount. Further, if the treatment is carried out with a calender, a super calender or the like in order to improve these drawbacks, the porous structure of the coating layer will be crushed, and the absorption rate and the absorption amount of the ink will be reduced. Further, when the ink jet recording paper is manufactured by a conventional coating and drying method, the immersion elongation is higher than that of the base paper, and deformation such as wrinkles and waving is likely to occur during multicolor recording, and in terms of dimensional stability. The fact is that it is not possible to obtain a satisfactory one. That is,
In the conventional method, the base paper expands in the coating step and shrinks rapidly in the drying step, so that uneven distortion occurs in the paper layer, which is a factor of poor dimensional stability. For this reason, in the conventional method, the base paper used for the multicolor and high-quality ink jet recording paper is unsatisfactory in terms of dimensional stability unless a base paper having extremely low water elongation is selected and used.
In this regard, reference is made to the contents described in JP-B-6-94229.

On the other hand, according to the cast coating method of the present invention, such a problem can be solved at once.

[0054]

As described above, according to the present invention, excellent ink absorbency, clear printing with almost no bleeding, extremely excellent fading resistance, and smoothness and glossiness of the recording paper surface are obtained. And the cost can be reduced as compared with the case where silica is used as a pigment.

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Akira Takeda 5-1 Kamiyacho, Iyo Mishima City, Ehime Prefecture Daio Paper Co., Ltd. F-term (reference) 2C056 EA05 EA13 FC06 2H086 BA16 BA33 BA34 BA35 BA48 4J002 AA011 AB021 AB031 AB041 AD001 AD011 AD021 BB061 BC051 BE021 BF021 BG041 BG051 BG061 BH011 DE236 FD096 GK03

Claims (3)

[Claims] An ink-absorbing precoat layer containing a pigment as a main component is provided on a base paper, and a transparent or translucent ink-receiving layer containing an acrylic cationic water-absorbing and releasing resin as a main component is provided on the ink-absorbing precoat layer. High gloss inkjet recording paper characterized by being sequentially laminated. 2. The pigment has a specific surface area of 50 to 130 m ^2.
2 g / g of light calcium carbonate, contained in the ink absorbing precoat layer in an amount of 70% by weight or more, and containing 5 to 50 parts by weight of a binder based on 100 parts by weight of the light calcium carbonate. The high gloss ink jet recording paper as described. 3. The high gloss ink jet recording paper according to claim 1, wherein said ink absorbing precoat layer is formed by a cast coating method.