JPH0820160A - Ink jet recording paper - Google Patents

Abstract

PURPOSE:To provide ink jet recording paper excellent in color developability, ink absorbability and transparency. CONSTITUTION:Ink jet recording paper consists of base paper based on cellulose pulp and the ink receiving coating layer formed on one surface of the base paper and containing white pigment and a resin as main components and the opacity of the base paper is 50% or less and a stearic acid type lubricant is added to the ink receiving coating layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is an ink jet recording sheet for use in printers, plotters and the like using aqueous inks, capable of recording images having excellent color development and dot shape characteristics. In addition, the present invention relates to a water-based inkjet recording sheet that can be used as tracing paper for drawings and the like because the recording sheet is translucent.

[0002]

2. Description of the Related Art Improvements in ink jet printer performance and inks that use aqueous ink have made it possible to obtain clear images and print quality using plain paper as the ink jet paper. However, on the other hand, in order to make print quality, saturation, appearance, and images more attractive, recording materials having more advanced characteristics are required. In particular, due to improvements in printing speed, resolution, saturation, etc., higher-level characteristics such as high-speed absorption, high absorption capacity, and regular ink bleeding are required for recording materials as well, and ink receptivity is increased. So-called coated paper having a coating layer on its surface has been developed. For example, Japanese Patent Application Laid-Open No. 62-158084 discloses a method for producing an inkjet recording medium having high water-based ink absorbency, color reproducibility and color density, which uses fine particle synthetic silica.
That is, in order to comply with the above-mentioned required characteristics, a coating layer containing a white pigment having an excellent liquid absorbing property such as fine particle synthetic silica as a main component may be provided on the surface of a base paper containing cellulose pulp as a main component. It is usually practiced.

On the other hand, in recent years, due to the expansion of the use of ink jet printers, especially the market development of ink jet plotters, in the field of design and drawing, a drawing method using a CAD system using a computer has been generally used instead of a conventional drawing method by handwriting. It's starting. As an inkjet drawing paper, a general plain paper / coated paper type to a translucent type for diazo copy (for example, tracing paper) is required. As a translucent type inkjet paper, for example, in JP-A-5-246130, transparent ink jet paper obtained by coating a transparent polymer with a hydrophilic polymer compound containing silica and an emulsion type cationic conductive agent having a particle size of 3 to 10 μm. Paper is disclosed. On the other hand, as a film for an overhead projector (hereinafter abbreviated as OHP), for example, JP-A-60-1458 is used.
No. 79 discloses a sheet in which a mixture of polyvinyl alcohol and polyvinylpyrrolidone having a saponification degree of 75% or more is coated on a polyethylene terephthalate film, and also JP-A-6-63.
JP-A No. 1-193879 discloses a sheet in which a mixture of water-soluble cellulose and polyvinylpyrrolidone is applied onto a polyester film.

However, in these recording sheets, a hydrophilic resin is used as the ink receiving layer, and the ink is fixed by the water absorbing / swelling action of the resin, so that the sheet surface becomes sticky or sweat due to moisture in the atmosphere. When touching the sheet with a hard hand, fingerprints may be transferred, or problems such as blocking between sheets may occur. Therefore, translucent paper capable of inkjet recording that solves these problems has been desired. .

[0005]

DISCLOSURE OF THE INVENTION The present invention is capable of printing high-quality images at high speed using an ink jet printer and plotter using water-based ink, and the paper is semi-transparent. It is an object of the present invention to provide a water-based inkjet recording paper that can be used as a printed material such as a diazo copy original.

[0006]

In view of the above situation, the present inventors have made earnest studies on a recording paper having transparency of the base paper and the ink-receptive coating layer, water absorption of the coating layer, and ink jet recording suitability. By providing an ink-receptive coating layer containing a white pigment, a hydrophilic resin, and a stearic acid-based lubricant as a main component on a base paper having a low opacity of cellulose pulp as a main component, printing can be performed by an inkjet printer / plotter, Moreover, since the opacity of the printed matter is low, it can be used for drawings and the like, and the stickiness of the paper is eliminated. Further, generally, the smaller the particle size of the white pigment, the more the ink-receptive coating layer using the pigment becomes Although the opacity increases, the opacity decreases again when the thickness is 1 μm or less, and the refractive index of the pigment is changed to that of cellulose (about 1.
It was found that the opacity of the ink-receptive coating layer can be suppressed to a low level by approaching 49), and the present invention has been completed.

That is, the ink jet recording paper of the present invention comprises a base paper containing cellulose pulp as a main component, and an ink receptive coating layer formed on one surface of the base paper and containing a white pigment and a resin as main components. And the opacity of the base paper is 50% or less, and a stearic acid-based lubricant is contained in the ink-receptive coating layer. Preferably, the particle size of the white pigment in the ink-receptive coating layer is 1 μm or less, and the refractive index is 1.4 to.
It is characterized in that it is in the range of 1.6, and that polyvinylpyrrolidone is contained as a resin in the ink receiving coating layer.

The pulp material contained in the sheet support used in the present invention is a softwood such as Akamatsu, Kuromatsu, Ezomatsu, Todomatsu, Japanese cedar, and hardwood such as beech, hippopotamus, and Japanese cypress. , Kraft pulp, semi-chemical pulp, chemi-ground pulp, refiner ground pulp, or used paper pulp. The base paper as the sheet support used in the present invention includes clay, talc, light calcium carbonate, calcined kaolin, aluminum oxide, aluminum hydroxide, inorganic pigments such as titanium oxide, alkyl as an additive in addition to the above wood pulp. Ketene dimer, internal sizing agent such as alkenylsuccinic acid, fixing agent such as sulfuric acid band, cationic starch,
A base paper produced by a known paper machine by appropriately selecting and internally adding a paper strength enhancer such as a polyacrylamide polymer and starch is preferably used. In addition, in order to increase the transparency of the base paper, pulp fibers are beaten to a high degree to extremely reduce voids, and paper is made. , Polyester resin, styrene resin, acrylic resin, amino resin, urethane resin, etc. after impregnated with a resin generally called a clarifying agent, and if necessary, it is processed by known equipment such as machine calender and super calender To be done.
The base paper of the present invention preferably has an opacity of 50% or less. When the opacity exceeds 50%, it becomes difficult to use it for diazo copy, which is one of the uses of the recording paper of the present invention, and thus it is not suitable.

The white pigment used in the ink-receptive coating layer used in the present invention is porous and has a high ink absorptivity,
It is preferable that the main component is one that enables clear color development. Such pigments include finely divided synthetic silica, precipitated calcium carbonate, ground calcium carbonate, calcium silicate, aluminum hydroxide, zeolite, calcined clay,
Examples include pigments generally used for paper coating, such as kaolin clay, talc, white carbon, and organic pigments (plastic pigments).

In particular, the white pigment used in the present invention has an average particle size of 1 μm or less and a refractive index of 1.4 to 1.6.
Is preferred. When the average particle diameter exceeds 1 μm, the opacity increases as described above, and when the refractive index is out of the above range, the opacity also increases, which is not suitable. The use ratio of such a white pigment is 10 to 50% by weight based on 100 parts by weight of the total amount of the white pigment and the resin in the total solid content of the coating layer. If it is less than 10%, the ink absorbency may be insufficient,
Stickiness occurs in the ink-receptive coating layer, and if it exceeds 50%, the opacity of the ink-receptive coating layer increases, which is not suitable.

As the resin of the present invention, it is desirable to use polyvinylpyrrolidone having good water absorption. In addition to polyvinylpyrrolidone, polyvinyl alcohol and polyvinyl alcohol derivatives modified with silanol groups, proteins such as casein, starch, and derivatives such as oxidized starch, styrene-butadiene copolymer, methyl methacrylate-butadiene copolymer Conjugated diene polymer latex such as, acrylic polymer latex such as polymer or copolymer of acrylic acid ester and methacrylic acid ester, vinyl polymer latex such as ethylene-vinyl acetate copolymer, or various of these Polymeric carboxyl group, functional group-containing modified polymer latex such as cationic group, melamine resin, synthetic resin-based water-based adhesive such as thermosetting resin such as urea resin, maleic anhydride copolymer resin system,
Polyacrylamide type, polymethylmethacrylate type, polyurethane resin type, unsaturated polyester resin type,
Polymers such as polyvinyl butyral-based and alkyd resin-based synthetic resin adhesives have good adhesiveness with pigments and good affinity with water-based inks, so they can be used together to prevent stickiness and blocking. it can. .

The ratio of the resin used in the ink-receptive coating layer is 10 in total of the white pigment and the resin in the total solid content of the coating layer.
It is 50 to 90% by weight with respect to 0 part by weight. If it is less than 50%, the water absorbency and adhesiveness will be insufficient, and there is a concern that the ink absorption capacity and strength of the coating layer will decrease. On the other hand, if it exceeds 90%, the adhesiveness is increased, but the use ratio of the pigment is reduced, and as described above, tackiness or blocking occurs due to moisture in the atmosphere, which is not suitable.

The stearic acid-based lubricant used in the present invention is appropriately selected from barium stearate, calcium stearate, zinc stearate, aluminum stearate, magnesium stearate and composites thereof. The use ratio of the stearic acid-based lubricant in the ink receiving coating layer is 1 in total of the white pigment and the resin.
It is 5 to 50% by weight with respect to 00 parts by weight. If it is less than 5%, the effect of preventing blocking cannot be expected. On the other hand, if it exceeds 50%, the ink absorbency is affected, which is not suitable.

In addition, as additives, pigment dispersants, defoamers, antioxidants, ultraviolet absorbers, viscosity modifiers, surfactants, wetting agents, cross-linking agents, and water resistance of prints after ink jet recording. A cationic resin or the like for improving is appropriately used according to production conditions, printing quality, and required performance.

Known coating equipment such as a bar coater, an air knife coater, a blade coater and a gravure coater is applied to apply the coating material of the present invention. The sheet provided with the ink-receptive coating layer on the base paper can be used as it is as the recording sheet of the present invention, but it can be treated with, for example, a super calendar or a gloss calendar to give the surface smoothness. Is.

The coating amount of the ink absorbing coating layer of the present invention is
Determined by end use, ink absorbency, recording properties,
It is not necessary to increase the amount unnecessarily as long as the storability and the like are satisfied, and it is appropriately selected and used from the range of 1 to ²⁰ g / m ² . If the ink-receptive coating layer is less than 1 g / m ² , the ink absorption capacity is insufficient in many cases, the image runs out, the drying is slow, and the ink adheres to the roll and becomes dirty. Also,
Since the amount of ink absorbed by the base paper is large, there is a problem that curling and unevenness are likely to occur. However, when an ink-receptive coating layer having a thickness of more than 20 g / m ² is provided, the adhesiveness with paper is weakened due to the thick coating layer, and the coating layer that has peeled off causes problems such as clogging of the head nozzle. In many cases, the cost is high. In addition, the opacity of the entire sheet is high, which is not suitable.

[0017]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto. In addition, "part" in Examples and Comparative Examples is "part by weight of solid content" unless otherwise specified.

Example 1 In a slurry of 100 parts of hardwood bleached kraft pulp beaten to 120 ml of Canadian standard freeness,
Cationic starch 0.9 parts, was added 0.12 parts of alkyl ketene dimer-based neutral sizing agent, thoroughly mixed and a paper stock, long net multi-cylinder type paper machine basis weight 68 g / m ² of the semi using A clear wood free paper was prepared. The quality paper obtained has an opacity of 4
5%. 11 g / m of the paint-1 was applied to one side of the obtained high-quality paper in a laboratory using a test bar coater.
^A coating layer was formed by coating at a ratio of ² and drying to prepare an inkjet recording paper.

Paint-1 Calcium carbonate 30 parts (trademark: soften, particle size 0.7 μm, refractive index 1.5, made by Bihoku Kogyo Kogyo Co., Ltd.) Polyvinylpyrrolidone 70 parts (trademark: rubiscol, made by BASF) Zinc stearate 10 Part (Trademark: High Micron F-930, Chukyo Yushi Co., Ltd.)

Example 2 On one side of the semitransparent high-quality paper produced in Example 1, 12 g / g of Paint-2 was used in a laboratory using a test bar coater.
A coating layer was formed by coating at a ratio of m ² and drying to form an inkjet recording paper.

Paint-2 Kaolin 30 parts (Trademark: Hydragross, particle size 0.2 μm, refractive index 1.56, manufactured by Nissei Kyoyasu) Polyvinylpyrrolidone 70 parts (Trademark: rubiscol, manufactured by BASF) Zinc stearate 25 parts (Trademark: High Micron F-930, Chukyo Yushi)

Example 3 70 parts of hardwood bleached kraft pulp, softwood bleached kraft pal
1.0 part of alkyne starch and alkly in 30 parts of slurry
Add 0.2 parts of luketene dimer type neutral size,
Mix into minutes to make a papermaking raw material, using a fourdrinier multi-cylinder paper machine
Tsubo 63g / m ² A fine paper was produced. The obtained fine paper
, An aliphatic saturated hydrocarbon clearing agent (trademark: Clariten
40% toluene diluted solution of DC, manufactured by Daiwa Chemical Industry Co., Ltd.
Impregnation using a strike impregnation machine, drying, curing, and impermeable
A semi-transparent high-quality paper having a brightness of 38% was produced. The obtained fine paper
Using a test bar coater in the laboratory on one side of
Paint-2 10g / m² Coating, drying and coating
An ink jet recording paper was prepared by forming a tank.

Example 4 On one side of the woodfree paper obtained in Example 1, in a laboratory,
The coating material-3 was applied at a rate of 11 g / m < ² > using a test bar coater and dried to form a coating layer, thereby manufacturing an inkjet recording paper.

Paint-3 Calcium carbonate 30 parts (trademark: Univer 70, particle size 2.5 μm, refractive index 1.57, manufactured by Shiraishi Industry) Polyvinylpyrrolidone 70 parts (trademark: rubiscol, manufactured by BASF) Zinc stearate 25 parts (Trademark: High Micron F-930, Chukyo Yushi)

Example 5 On one side of the woodfree paper obtained in Example 1, in a laboratory,
Paint-4 was applied at a rate of 10 g / m ² using a test bar coater and dried to form a coating layer, to produce an inkjet recording paper.

Paint-4 Calcium carbonate 30 parts (trademark: soften, particle size 0.7 μm, refractive index 1.5, made by Bihoku Kogyo Kogyo) Polyvinyl alcohol 70 parts (trademark: PVA-403, made by Kuraray) Zinc stearate 20 parts (Trademark: High Micron F-930, Chukyo Yushi)

Example 6 On one side of the woodfree paper obtained in Example 1, in a laboratory,
Coating material-5 was applied at a rate of 11 g / m < ² > using a test bar coater and dried to form a coating layer, thus producing an inkjet recording paper.

Paint-5 Titanium oxide 30 parts (Trademark: Taipaque, particle size 0.15 μm, refractive index 2.52, manufactured by Ishihara Sangyo) Polyvinylpyrrolidone 70 parts (trademark: rubiscol, manufactured by BASF) Zinc stearate 25 parts ( Trademark: High Micron F-930, Chukyo Yushi)

Comparative Example 1 On one side of the woodfree paper obtained in Example 1, in a laboratory,
The coating material 6 was applied at a rate of 9 g / m ² using a test bar coater and dried to form a coating layer, thus producing an inkjet recording paper.

Paint-6 Calcium carbonate 30 parts (trademark: soften, particle size 0.7 μm, refractive index 1.5, made by Bihoku Kogyo Kogyo Co., Ltd.) Polyvinylpyrrolidone 70 parts (trademark: rubiscol, made by BASF)

Comparative Example 2 Canadian Standard Freeness (CSF) 180
70 parts hardwood bleached kraft pulp beaten to ml and CSF
To a slurry prepared by mixing 30 parts of bleached softwood kraft pulp beaten to 150 ml, 0.9 parts of katin starch and 0.1 part of an alkyl ketene dimer neutral sizing agent were added and sufficiently mixed to prepare a papermaking raw material. Using a net multi-cylinder type paper machine, semi-transparent high-quality paper with a weight of 75 g / m ² was produced. The opacity of the obtained high-quality paper was 62%. On one side of the obtained high-quality paper, in a laboratory, a paint-1 was applied at a rate of 11 g / m ² using a test bar coater and dried to form a coating layer, thereby producing an inkjet recording paper.

Table 1 shows the evaluation results of these coated papers. The inkjet recording characteristics were evaluated by the following methods. Inkjet printer (trademark: BJC-600
J, manufactured by Canon) was used for the ink absorption and the vividness of color development. To evaluate the ink absorbency, the number of seconds until the printed ink dries was measured. 30 seconds or less is indicated by O, 30 to 90 seconds is indicated by Δ, and 90 seconds or more is indicated by X. For the vividness of color development, the color development of yellow, magenta and cyan color inks was visually evaluated. Good color development is indicated by O, insufficient color development is indicated by Δ, and defective color is indicated by X. The suitability for tracing paper is that the character or pattern is placed under the ink jet recording paper of the present invention, and the characters and patterns underneath can be seen well. The ones were evaluated as Δ, and those difficult to recognize were evaluated as x. For the blocking of the paper, the ink-receptive coating layer was touched by hand, and the non-sticky one was marked with ◯, the slightly sticky one was marked with Δ, and the sticky one with hand was marked with x. The opacity was determined by the method described in JIS-P-8138.

[0033]

[Table 1]

As is clear from Table 1, according to the present invention, the ink absorbency, the vividness of color development, the suitability for tracing paper, and the blocking are all very excellent (Examples 1, 2, 3). . In addition, a white pigment having a large particle size or a high refractive index was slightly inferior in the suitability for tracing paper (Examples 4 and 6), and one in which polyvinylpyrrolidone was not used as a resin had a slightly poor ink absorbing property (Implementation). Example 5) had no problem in practical use. However, as can be seen from Comparative Examples, those without the stearic acid type lubricant caused blocking (Comparative Example 1), and those with high opacity of the base paper were inferior in tracing paper suitability (Comparative Example 2).

[0035]

INDUSTRIAL APPLICABILITY The ink jet recording paper of the present invention is not only excellent in ink absorption and color development, but also semitransparent, so that it can be used as a tracing paper for drawings and the like. Has the effect of doing.

Claims (4)

[Claims] 1. A base paper comprising cellulose pulp as a main component, and an ink-receptive coating layer formed on one surface of the base paper and containing a white pigment and a resin as main components. The inkjet recording paper is characterized by having an opacity of 50% or less and containing a stearic acid-based lubricant in the ink-receptive coating layer. 2. The ink jet recording paper according to claim 1, wherein the particle size of the white pigment in the ink receptive coating layer is 1 μm or less. 3. The ink jet recording paper according to claim 1, wherein polyvinyl pyrrolidone is contained as a resin in the ink receptive coating layer. 4. The ink jet recording paper according to claim 1, wherein the white pigment in the ink receptive coating layer has a refractive index of 1.4 to 1.6.