JP3136097B2 - Manufacturing method of inkjet recording paper - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates not relate jet recording sheet, more particularly, excellent ink absorbency, with showing the fixability, high-quality image quality of an ink jet recording paper obtained with a high gloss It relates to a manufacturing method.

[0002]

2. Description of the Related Art Inkjet printers have features such as clearness of recording, quietness of sound, and ease of colorization.
Ink jet printers use ink that is difficult to dry in order to prevent clogging of the jet nozzle due to drying of the ink. In general, such an ink is obtained by dissolving or dispersing a binder, a dye, a solvent, an additive, and the like in water. Therefore, an ink jet recording paper used in an ink jet printer is required to have water absorbency. Therefore, an ink jet recording sheet provided with a performance of sufficiently absorbing ink is usually used.

[0003] Such an ink jet recording paper is mainly composed of polyvinyl alcohol and glycerin, lithium chloride, starch, gelatin, hydroxyethylcellulose or carboxymethylcellulose in order to obtain good receptivity to aqueous ink, that is, ink absorption. And the like, an ink-receiving layer is formed by applying a water-based paint containing a material having a wettability to the ink for an ink jet printer on a substrate. However, with the spread of ink jet printers capable of full-color printing in recent years, ink jet recording papers having high glossiness, particularly art paper, have been demanded. Ink jet recording paper provided with an ink receiving layer having such a high gloss is generally produced by a cast coating method or a highly calendered treatment, and therefore has a high air permeability, and has an ink absorbing property (drying property). ) Tended to be inferior, and the print density was lowered, so that the recording characteristics were not sufficiently satisfactory. In short, the ink jet recording paper according to the prior art cannot achieve both high glossiness, ink absorbency and good recording characteristics.

[0004]

SUMMARY OF THE INVENTION In view of the circumstances described above, an object of the present invention is to provide a full-color print for a high-gloss image having a high print density and a high gloss, and excellent ink absorptivity. A method for producing paper is provided.

[0005]

According to the present invention , an ink receiving layer is provided by applying and drying a paint containing a pigment and a binder as main components on the surface of a paper substrate, and a pigment and a pigment are provided on the ink receiving layer. After applying the coating material for the gloss layer containing a binder as a main component, the resin film was overlaid in a state where the coating material for the gloss layer was not dried, and then the coating material for the gloss layer was dried to form a gloss layer. After that, the resin film is peeled off and the surface of the gloss layer is removed.
With glossiness of 35 or more and Oken type smoothness of 120-300 seconds
Yes, and the air permeability is 60 to 120 seconds / 100 cc
A method for producing an ink jet recording sheet.

As the paper substrate used in the present invention, paper made of pulp raw material mainly composed of natural cellulose fibers is applied, and its composition and production method are not particularly limited. For example, it is produced by a wet papermaking method. Paper is appropriately used. Specifically, softwood as a pulp raw material, kraft pulp produced by blending hardwood alone or appropriately,
Wood pulp such as sulfite pulp and semi-chemical pulp is used, and bleached pulp is preferable for obtaining clear printing. Further, non-wood pulp such as waste paper pulp, bagasse, kenaf, cotton, hemp, espart, bamboo, straw, etc. can also be used.

In the present invention, in order to control the air permeability of the ink jet recording paper to 60 to 120 seconds / 100 cc, the air permeability of the paper substrate should be 80 seconds / 100 cc or less, especially 30 to 60 seconds / 100 cc. Is preferred. In order to obtain such air permeability, a sizing agent, a wet strength agent, a filler, and the like are used as internal chemicals by using a stock obtained by adjusting the degree of beating of the pulp raw material to 30 to 50 ° SR as described above. The papermaking may be carried out by appropriately blending it with the ingredients. The air permeability can also be controlled by applying a surface paper strength enhancer by size press coating or coating after papermaking during papermaking.

The paper substrate has a Steckigt sizing degree of 1%.
It is preferably from 0 to 100 seconds. If the Stekigt sizing degree is less than 10 seconds, the ink-receiving layer coating material may be soaked when the ink-receiving layer is provided, the air permeability may be too high and the ink-accepting property may be impaired.
If the time exceeds 00 seconds, the adhesion of the ink receiving layer to the paper substrate may be deteriorated. The sizing agent used in the present invention is not particularly limited. An acrylic resin, a styrene-maleic acid-based resin, and the like can be given. In addition,
The sizing agent was added in an amount of 0.1 to 100 parts by weight of pulp.
To 1.0 part by weight.

[0009] Wet paper strength agents are used to improve the Stechig sizing of the paper base and to impart water resistance to the pulp.
It is used in an amount of 0.01 to 1.0 part by weight with respect to 0 part by weight, and examples thereof include, but are not limited to, melamine resin, polyamide epichlorohydrin resin, urea resin and the like. In addition, the filler controls the smoothness to facilitate formation of the ink receiving layer, and enhances the opacity to contribute to the concealing property. If necessary, 10 parts by weight or less based on 100 parts by weight of the pulp. Preferably 0
~ 5 parts by weight are added. As the filler, for example, kaolin, clay, talc, titanium dioxide, calcium carbonate and the like are used.

[0010] The surface paper strength enhancer is intended to improve the air permeability of the paper substrate and the degree of stiffen size, and is, for example, oxidized starch, esterified starch, polyacrylamide, acrylic resin, polyvinyl alcohol, SBR, NBR. ,
A vinyl oxide resin or the like can be used after being coated with a size press of a paper machine or an off-machine coater.
The amount of coating is preferably about 0.5 to 2.5 g / m ² .

[0011] Further, as a chemical additive for internal addition to the pulp raw material, an internal paper strengthening agent such as starch, modified starch, carboxymethyl cellulose, polyacrylamide, and styrene resin, a coloring agent, a fixing agent such as a sulfuric acid band and polyacrylamide, Further, as a coating chemical, in addition to the surface paper strength enhancer, a dialdehyde starch, a melamine resin, a water-resistant agent such as a polyamide resin, an antistatic agent, a water repellent, a lubricant, a surface sizing agent, a pigment, and the like are required. Can be used accordingly.

The ink jet recording paper of the present invention has a structure in which an ink receiving layer and a gloss layer are sequentially laminated on at least one surface of the paper substrate as described above. Here, the ink receiving layer contains a pigment and a binder as main components, and there is no particular limitation on the mixing ratio, the forming method, the layer configuration, and the like. As an example of the ink receiving layer,
For example, acrylic resin, polyester resin, polyurethane resin, styrene-butadiene copolymer resin, acrylonitrile-butadiene copolymer resin, polyvinyl alcohol resin, water-soluble polyvinyl acetal resin, polyvinyl butyral resin, other vinyl resins, and amide resins Water-soluble resins and aqueous emulsion resins such as oxidized starch, casein, polyethylene oxide, polyvinylpyrrolidone, silicone resin, rosin-modified maleic resin, rosin-modified phenol resin, alkyd resin, and cumarone-indene resin as binders Used, silica, clay, mica, swellable mica, talc, kaolin, diatomaceous earth, calcium carbonate, barium sulfate, aluminum silicate, synthetic zeolite, alumina, zinc oxide, lithopone,
It is composed of a pigment such as satin white and an organic or inorganic coloring pigment.

The composition of the ink receiving layer in the present invention may be a binder such as polyvinyl alcohol resin, water-soluble polyvinyl acetal resin, polyvinyl pyrrolidone, etc., from the viewpoints of ink absorption, ink drying, and clearness of recorded images. Is preferable, using a water-soluble resin of the formula (1) and silica as a pigment. In this case, the mixing ratio is preferably resin: silica = 1: 1 to 1:15, and particularly preferably 1: 2 to 1:15.
10 is preferred. Such silica is not particularly limited, but those having an average particle diameter of 1 to 25 μm (volume average particle diameter by a Coulter counter method) are preferred, and those having an average particle diameter of 5 to 25 μm are particularly preferably used.

In the ink receiving layer in the present invention, melamine formaldehyde resin, urea formaldehyde resin, acrylamide resin, glyoxal, zirconium ammonium carbonate and the like are used as other additives for improving the water resistance and imparting the function of preventing ink bleeding. May be added. In order to further improve the productivity, recording characteristics, or storage stability of the ink jet recording paper, a dispersant, a fluorescent dye, a pH adjuster, a defoaming agent, a lubricant,
Various additives such as preservatives may be added.

In providing the ink receiving layer, a coating liquid prepared by dissolving or dispersing the material for forming the ink receiving layer in water or a suitable solvent is used, for example, by a roll coating method, a blade coating method, or an air knife coating method. It can be formed by coating on a substrate by using a method such as a rod bar coating method, a gravure coating method, a comma coating method, and a die coating method as appropriate. The coating amount after drying of the ink receiving layer, 5 to 30 g / m ² are preferred, particularly preferably 10 to 20 g / m ^2. Here, the application amount is 30 g /
neither shall also characteristic it is particularly well with more than m ^2,
If it is less than 5 g / m ² , the ink absorbency may not be sufficient.

The gloss layer according to the present invention contains a pigment and a binder as main components, and has a surface glossiness of 35 or more (as measured by 60 ° specular glossiness specified in JIS Z8741). Oken type smoothness is 120 ~
300 seconds (JAPAN TAPPI paper pulp test method N
o. 5), preferably 1
60 to 240 seconds. Here, when the glossiness is less than 35 or when the Oken type smoothness is less than 120 seconds, the appearance is insufficient in glossiness, not only inferior as a high gloss ink jet recording paper, but also the printing density is insufficient. This is inferior in recording characteristics such as blurring in printing. Also,
If the Oken type smoothness is greater than 300 seconds, there is a problem that the ink drying property is impaired. The characteristics of the surface of the gloss layer can be controlled as described above by forming the gloss layer with the following composition by the following production method.

The composition of the glossy layer contains a pigment and a binder as main components. As the pigment and the binder, those similar to those used for the ink receiving layer can be applied. The mixing ratio of the pigment and the binder is
The binder is preferably used in an amount of 5 to 50% by weight, more preferably 5 to 30% by weight, based on the pigment. Further, it is preferable to use colloidal silica as a pigment because glossiness, ink drying property, print clarity and the like are particularly excellent. The dry coating amount of the gloss layer is preferably 5 to ²⁰ g / m ² . If the coating amount is less than 5 g / m ² , gloss and smoothness cannot be obtained. If the coating amount is more than 20 g / m ² , the coating will protrude from the edge of the sheet when a resin film described later is overlaid, causing a problem in manufacturing. May be present.

The ink jet recording paper of the present invention has the above-mentioned constitution, and is formed by appropriately controlling the composition and application amount of the paper substrate, the ink receiving layer and the gloss layer, and the production conditions for forming the gloss layer described later. Air permeability is 60-1
20 seconds / 100 cc (using a Japan TAPPI paper pulp test method No. 5 Oken type air permeability tester). If the air permeability is less than 60 seconds / 100 cc, the ink absorbency is too good, causing problems such as print bleeding and so-called show-through where the ink has penetrated to the back surface of the recording paper. If it is too large, the ink absorbency will be impaired.

The ink jet recording paper of the present invention having the above constitution can be manufactured as follows. First, a paint for an ink receiving layer having the above composition is applied to the surface of a paper substrate and dried to form an ink receiving layer. The formation method in this case is not particularly limited as described above. Further, the ink receiving layer may have a laminated structure of two or more layers.

Next, a paint for a gloss layer having the above composition is applied on the ink receiving layer, and a resin film is overlaid in a state where the paint for the gloss layer is not dried. In this case, the undried state of the gloss layer coating refers to a state in which a coating is not formed on the surface of the coating, and particularly a state in which the coating contains 70% by weight or more of a dry volatile component in the coating, that is, the coating in the coating. Is preferably in a state in which the solid content concentration is 5 to 30% by weight. If the solid content concentration in the paint is more than 30% by weight, the glossiness of the surface of the glossy layer may not be sufficiently obtained, or the air permeability may be too high to impair the ink drying property, which is not preferable. In addition, a paint having a solid content of 5% by weight or less has a large amount of volatile components and requires a long time for drying, which is not preferable in production.

The method for applying the gloss layer is not particularly limited, and for example, a method such as an air knife coating method, a rod bar coating method, a gravure coating method, and a reverse roll coating method can be used as appropriate. In order to overlap the resin film after the application of the glossy layer paint, it is sufficient that the resin film is at least undried as described above. preferable. In addition, the superposition can be performed by appropriately controlling the conditions (pressure, temperature, etc.) through two rolls (nip rolls). The nip roll pressure is about 3 to 5 kg / cm ² as described above. Preferred for achieving the value. The resin film to be superimposed is not particularly limited, but has a high smoothness (Beck smoothness of 5).
2,000 seconds or more), a resin film of polyester, polypropylene, polyethylene, polyimide, or the like, or a resin film obtained by subjecting these to releasable silicone processing can be used as appropriate.

After laminating the resin films as described above, the glossy layer paint is dried to form a glossy layer, and then the resin film is peeled off to produce the ink jet recording paper of the present invention. it can. In the drying of the gloss layer paint, the solvent evaporates from the paper substrate side because the resin film is overlaid, and the drying conditions affect the air permeability and the smoothness of the gloss layer surface. Therefore, it is necessary to appropriately control the drying conditions (temperature, speed, etc.) according to the composition of the glossy layer paint. In addition, the peeling conditions (angle, speed, etc.) of the resin film also affect the glossiness of the surface of the gloss layer and the Beck smoothness.

[0023]

Next, the present invention will be described with reference to examples. Example 1 A pulp raw material composed of 50% by weight of NBKP and 50% by weight of LBKP was prepared with a beater to a beating degree of 45 ° SR, and a fourdrinier paper machine was used with a raw material obtained by adding an internal additive to the pulp at the following ratio. After papermaking, a coating liquid comprising the following coating chemicals was applied at 1.0 g / m ² by a size press and dried to prepare a paper substrate. (Internally added chemicals) Clay (manufactured by Kanaya Kogyo Co., Ltd., special grade clay) 2.25% by weight Talc (manufactured by Nippon Talc, SWB) 2.25% by weight Melamine resin (Sumitomo Chemical Co., Ltd., Sumireze resin 607SY) 0.23 Weight% Rosin sizing agent (Arakawa Chemical Co., Size Pine E) 0.5% by weight Sulfuric acid band (Nippon Light Metal Co., Ltd.) 2.7% by weight (coating chemical) Oxidized starch (Nippon Cornstarch, SK-20) 20 parts by weight Polyacrylamide (Arakawa Chemical Co., Polymer Set 305) 40 parts by weight Normal salt 0.5 part by weight Water 500 parts by weight

On one side of the above-mentioned paper base material, a paint for an ink receiving layer having the following composition is applied and dried to obtain a dry coating amount of 15%.
g / m ² of the ink receiving layer was provided. <Paint for ink receiving layer> 150 parts by weight of silica (trade name “Carplex BS304F” manufactured by Shionogi & Co., Ltd., average particle size 5.3 μm) ・ Polyvinyl alcohol (trade name “T-330” Nippon Gohsei Melamine-based crosslinking agent (trade name "SUMIREZ Resin SR613" manufactured by Sumitomo Chemical Co., Ltd., solid content 80%) 3.2 parts by weight

Next, a gloss layer paint having the following composition is applied on the ink receiving layer by a microgravure coater, and immediately thereafter (solid content: about 18.3%), a 25 μm-thick polyester film is overlaid. Nip roll (pressure 4
kg / cm ² ) and then through a floating drier (temperature: 120 ° C.) to obtain a dry coating amount of 12
A gloss layer of g / m ² was formed, and the polyester film was peeled off to obtain an ink jet recording paper of the present invention. <Coating for glossy layer>-250 parts by weight of silica (trade name "Snowtex UP" manufactured by Nissan Chemical Co., Ltd., solid content 20%)-Polyvinyl alcohol (trade name "Gohsenol T-330" manufactured by Nippon Synthetic Chemical Co., Ltd.) 50% by weight)

Example 2 An ink jet recording sheet of the present invention was produced in the same manner as in Example 1 except that the amount of the glossy layer dried was changed to 18 g / m ² . Example 3 An ink jet recording paper of the present invention was produced in exactly the same manner as in Example 1 except that the dry coating amount of the glossy layer was changed to 8 g / m ² .

Comparative Example 1 An ink jet recording sheet for comparison was prepared in exactly the same manner as in Example 1 except that the coating for the glossy layer was applied and then the polyester film was dried without overlapping. Comparative Example 2 A comparative inkjet recording sheet was prepared in exactly the same manner as in Example 1 except that the dry coating amount of the glossy layer was changed to 3 g / m ² .

Comparative Example 3 Example 1 was repeated except that polyvinyl alcohol was used alone without using silica as the coating material for the glossy layer in Example 1.
In the same manner as above, a comparative inkjet recording paper was produced. Comparative Example 4 Example 1 was repeated except that the polyester film was not superimposed immediately after the gloss layer coating was applied, but was dried once to a semi-dry state having a solid concentration of about 50% by weight, and then the polyester film was superimposed. In the same manner as in Example 1, a comparative inkjet recording paper was produced.

Comparative Example 5 A comparative inkjet recording paper was prepared in exactly the same manner as in Example 1 except that the glossy layer was formed directly on the paper substrate without forming the ink receiving layer. Comparative Example 6 A high-gloss inkjet recording paper (a glossy postcard manufactured by Canon Inc.) manufactured by a commercially available cast coating method was used for comparison as it was.

The glossiness, Oken-type smoothness and air permeability of the ink jet recording papers obtained in Examples 1 to 3 and Comparative Examples 1 to 6 were measured and cut into A4 size papers. Color printing was performed using “MJ-5000C” (manufactured by Seiko Epson Corporation) and ink for an inkjet printer (trade name “MJIC2C”, manufactured by Seiko Epson Corporation), and the results of evaluating various image characteristics are shown in the table. It is shown in FIG. As is evident from Table 1, the ink jet recording paper of the present invention has excellent glossiness and ink absorbency, and exhibits color development, print density,
Image characteristics such as bleeding were also good. On the other hand, the comparative inkjet recording paper had insufficient gloss and poor image characteristics.

[0031]

[Table 1]

The methods for evaluating various characteristics in Table 1 are as follows. (1) Ink absorption: After printing, the state of the ink remaining in the form of beads on the printing surface was visually observed and touched with a finger to evaluate the dryness. The evaluation criteria are as follows. ：: Little ink remains and no ink adheres to the finger. X: The ink is in the form of beads and remains much, and the ink adheres to the finger. Δ: Intermediate state between ○ and × (2) Coloring property: The printed sample was visually evaluated for image clarity and ink coloring property. The evaluation criteria are as follows. ：: good image quality ×: poor image quality △: intermediate state between ○ and ×

(3) Print density: The density of the black image portion was measured by Macbeth RD-914. (4) Bleeding: The dot reproducibility of the printed portion was visually evaluated using a stereoscopic microscope of 40 times. The evaluation criteria are as follows. ：: Printed dot is a circle or a shape close to a circle. ×: Dramatically bleeds and does not form a dot.

[0034]

According to the present invention, excellent ink absorptivity, high print density and high ink density are obtained, while having excellent glossiness, the ink does not adhere to the finger even when the recorded portion is touched with the finger. The present invention provides a recording sheet suitable for an ink jet printer which is excellent in printing characteristics and which can obtain clear image quality without blur or the like.

Claims (7)

(57) [Claims] 1. An ink receiving layer is provided by applying and drying a paint containing a pigment and a binder as main components on the surface of a paper substrate, and a pigment and a binder are contained as main components on the ink receiving layer. After applying the gloss layer paint, the resin film is overlaid with the gloss layer paint being undried, and then the gloss layer paint is dried to form a gloss layer, and then the resin film is peeled off. And the surface of the gloss layer has a glossiness of 35 or more and Oken type
Smoothness is 120 to 300 seconds, and air permeability is 60 to
A method for producing ink jet recording paper, characterized in that the recording time is 120 seconds / 100 cc . 2. The glossy layer contains colloidal silica as a pigment, and the compounding ratio of the binder to the pigment is 5 to 3.
2. The method according to claim 1, wherein the amount is 0% by weight . 3. A method of manufacturing an ink jet recording sheet according to claim 1, wherein the waterproofing agent is blended in the ink-receiving layer. 4. The solid content of the coating material for the glossy layer is 5 to 30% by weight.
Method for producing an ink jet recording sheet according to claim 1, wherein the superposition of the resin film in an undried state. 5. The method according to claim 1, wherein the air permeability of the paper substrate is 80 seconds / 100 cc or less. 6. A method for producing an ink jet recording sheet according to claim 1, wherein the paper substrate is those papermaking from a pulp feedstock of freeness 30-50 ° SR. 7. The paper substrate has a Stöckigt sizing degree of 10-1.
Method for producing an ink jet recording sheet according to claim 1, wherein the 00 seconds.