JP3672363B2 - Method for producing cast coated paper for inkjet recording, cast coated paper and recording method using the same - Google Patents

Description

【００７５】
【発明の効果】
表１の結果から明らかなように、本発明のキャスト塗被紙は表面光沢度、インクジェット記録適性及び耐候性に優れ、かつ効率良く生産することができた。
【図面の簡単な説明】
【図１】インクジェット記録装置のヘッド部の縦断面図。
【図２】インクジェット記録装置のヘッド部の横断面図。
【図３】図１に示したヘッドをマルチ化したヘッドの外観斜視図。
【図４】インクジェット記録装置の一例を示す斜視図。
【図５】アルミニウムアルコキシドの加水分解法によるアルミナの製法を説明する。
【符号の説明】
１３ ： ヘッド
１４ ： インクを通す溝
１５ ： 発熱ヘッド
１６ ： 保護膜
１７−１： アルミニウム電極
１７−２： アルミニウム電極
１８ ： 発熱抵抗体層
１９ ： 蓄熱層
２０ ： 基板
２１ ： インク
２２ ： オリフィス
２３ ： メニスカス
２４ ： 記録小滴
２５ ： 記録シート
２６ ： マルチ溝
２７ ： ガラス板
２８ ： 発熱ヘッド
５１ ： 給紙部
５２ ： 紙送りローラー
５３ ： 排紙ローラー
６１ ： ブレード
６２ ： キャップ
６３ ： インク吸収体
６４ ： 吐出回復部
６５ ： 記録ヘッド
６６ ： キャリッジ
６７ ： ガイド軸
６８ ： モ−ター
６９ ： ベルト[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a cast coated paper for ink jet recording, and in particular, a method for producing a cast coated paper for ink jet recording having excellent white paper surface gloss, excellent ink jet recording suitability and storage stability of recorded images, and cast coated paper, It relates to the recording method.
[0002]
[Prior art]
In recent years, recording by an ink-jet printer has been used in many fields because of low noise, high-speed recording, and easy multi-coloring.
As paper for inkjet recording, high-quality paper devised so as to have high ink absorbability, coated paper with a porous pigment coated on the surface, and the like are applied. By the way, all of these sheets are mainly so-called matte ink jet recording sheets having a low surface gloss.
[0003]
However, recently, with the expansion of applications such as high speed inkjet recording, high definition of recorded images, and full color, inkjet recording papers having high surface gloss and excellent appearance characteristics are being demanded.
In general, as a paper having a high surface gloss, a coated pigment having a high gloss or a wet coating layer is applied by applying a plate-like pigment on the surface and, if necessary, applying a pressure treatment with a calendar. A so-called cast coated paper or the like is known which is obtained by copying a mirror surface of the heated drum surface having a mirror surface and then drying it.
[0004]
In general, cast coated paper has a high surface gloss and superior surface smoothness compared to ordinary coated paper pressure-finished by a super calender, and exhibits an excellent printing effect. Although it is exclusively used for applications such as high-quality printed materials, it has various difficulties when used as an inkjet recording medium.
[0005]
That is, cast coated paper generally has a high gloss because a film-forming substance such as an adhesive in the pigment composition constituting the coating layer copies the mirror drum surface of the cast coater. On the other hand, the presence of the film-forming substance loses the porosity of the coating layer, and has problems such as extremely reducing ink absorption during ink jet recording. And in order to improve the ink absorbability, it is important to make it porous so that the ink can be easily absorbed into the cast coating layer. To that end, it is necessary to reduce the amount of film-forming substance It becomes. On the other hand, reducing the amount of film-forming substance results in a decrease in white paper gloss. As described above, it has been extremely difficult to satisfy both the surface gloss of the cast coated paper and the suitability for ink jet recording (printing) at the same time.
[0006]
[Problems to be solved by the invention]
The present invention relates to a process for producing a cast coated paper which maintains the original high smoothness and excellent glossiness of the cast coated paper, and exhibits extremely excellent ink jet printing recordability and excellent recorded image storage, and cast coated paper And a recording method thereof.
[0007]
[Means for Solving the Problems]
The present invention includes but is not limited to the following embodiments.
[1] Bulk density (JISH-1902) on the base paper is 0.04 to 0.2 g / cm ³ Is provided with a coating layer containing alumina and an adhesive, and further on the coating layer , Obtained by polymerizing a monomer having an ethylenically unsaturated bond and having a glass transition point of 40 ° C. or higher A method for producing a cast coated paper for ink jet recording, wherein a cast coating layer formed by coating a coating solution containing a resin is pressed and dried on a heated mirror drum while the cast coating layer is wet.
[0008]
[2] BET specific surface area of alumina 1.0 200m ² / g A method for producing a cast coated paper for ink jet recording according to [1].
[0010]
[ 3 ] The bulk density (JIS H-1902) of the base paper is 0.04 to 0.2 g / cm. ³ Is provided with a coating layer containing alumina and an adhesive, and further on the coating layer , Obtained by polymerizing a monomer having an ethylenically unsaturated bond and having a glass transition point of 40 ° C. or higher A cast coated paper for inkjet recording, which is obtained by casting a layer obtained by coating a coating solution containing a resin.
[0011]
[ 4 ] BET specific surface area of alumina is 1.0-200m ² / G [ 3 ] The cast coated paper for inkjet recording described in the above.
[0013]
[ 5 ] [3] An ink jet recording method for forming an image by ejecting water-based ink from fine holes on the cast coated paper for ink jet recording described above.
[0014]
[ 6 ] The ink is ejected by applying thermal energy to the water-based ink [ 5 ] The inkjet recording method of description.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
In the present invention, alumina contained in the undercoat layer, which is important for obtaining desired properties as product quality, will be described.
In the case of conventional ink jet recording paper, silica-based pigments have been mainly used for the purpose of obtaining advanced characteristics such as ink acceptability, clearness of print recording, high print density, color developability and gradation. However, this silica pigment is accompanied by the difficulty that the recorded image is likely to be discolored or discolored by exposure to oxygen in the air or sunlight.
[0016]
The present inventors have intensively studied to improve various quality characteristics that the above-described conventional inkjet recording paper has as a difficulty. As a result, the ink receiving layer of the coated paper for inkjet recording has a two-layer structure, and the bulk density (JIS H-1902) is 0.2 g / cm as a pigment to be contained in the undercoat layer. ^Three When the following low bulk density alumina is used and a cast coating layer is formed thereon, the above-mentioned difficulties are completely eliminated or reduced, and particularly excellent storage stability and excellent gloss and image quality can be obtained. I understood. Although the minimum of the bulk density of an alumina is not specifically limited, 0.04 or more are preferable, More preferably, it is 0.05-0.15.
[0017]
The bulk density of the present invention is the same as the heavy bulk specific gravity according to JIS H-1902, and the unit is g / cm. ^Three Is attached.
Alumina often has a plate-like structure, but scaly alumina is preferable because it easily embeds voids between particles.
In addition, the commercially available alumina has a bulk density of 0.4 g / cm. ^Three Above, many are 0.6-1.5 g / cm ^Three Degree.
[0018]
As described above, it is not always clear why the low bulk density alumina can be used, but the use of the low bulk density alumina makes the undercoat coating layer exhibit a very porous shape. It is estimated that the ink absorbency is thereby improved.
[0019]
The present invention has a great feature in using alumina having the above bulk density. The method for producing alumina is not particularly limited.
However, according to the hydrolysis method of aluminum alkoxide illustrated in FIG. 5, fine high-purity alumina can be obtained. That is, it is a method in which metal aluminum is reacted with an alcohol such as methanol to produce an aluminum alkoxide, which is then hydrolyzed to obtain aluminum hydroxide and then calcined to obtain alumina.
[0020]
The method for producing the low bulk density alumina is not particularly limited, but the desired bulk density can be obtained by appropriately combining conditions such as the temperature and time during firing or the type of hydrated alumina used as a raw material. Can be adjusted.
Among the low bulk density aluminas as described above, the BET specific surface area is preferably 200 m. ² / G or less. Thereby, the storability (weather resistance) of the printed image in inkjet recording is further improved. The BET specific surface area is based on the BET one-point method using a direct reading BET specific surface area measuring device Monosorb manufactured by Cantachrome.
[0021]
The lower limit of the BET specific surface area is not particularly limited, but is usually 1.0 m ² / G or more is preferable. Further, if it is too low, the ink absorbability may be lowered. ² / G or more, more preferably 100 m ² / G or more.
The BET specific surface area is affected by the shape of the alumina primary particles. There is no correlation between the bulk density and the BET specific surface area.
Although the average particle diameter of the primary particles of alumina is not particularly limited, it is about 0.01 to 1 μm according to an electron micrograph. However, since the secondary agglomeration causes the particle size distribution to be about 0.05 to 10 μm when the particle size distribution is measured by other methods such as a sedimentation method, this value varies depending on the dispersion method of the pigment dispersion. That is, the dispersion state changes depending on the slurry concentration, the presence or absence of the dispersant, the type of the disperser, and the change over time after the slurry is prepared.
In the case of cationic alumina (manufactured by Sumitomo Chemical Co., Ltd., trade name: AKP-G015), the primary particles are 0.1 μm or less, but about 0.8 wt% alumina in 0.2 wt% sodium hexametaphosphate solution For 10 minutes, the average particle size is about 2 μm, and when dispersed with a high dispersion type sand mill, the average particle size is about 0.5 μm.
[0022]
The alumina is preferably contained in an amount of 50 to 100% by weight in the total pigment of the undercoat coating layer.
If necessary, other pigments are generally used in the coated paper manufacturing field, such as kaolin, clay, calcined kaolin, amorphous silica, zinc oxide, aluminum hydroxide, calcium carbonate, satin white, aluminum silicate, magnesium silicate, carbonate Magnesium, plastic pigments and the like can be used as appropriate.
[0023]
The reason why the specific alumina of the present invention is contained as an essential component in the undercoat layer is that the color developability of the ink may be lowered if it is contained in a large amount in the cast coating layer. Cast coated paper This is because there is a possibility that the surface glossiness of the film may be lowered.
[0024]
Next, examples of the adhesive used in combination with the alumina include proteins such as casein, soybean protein, and synthetic protein, various starches such as starch and oxidized starch, cellulose derivatives such as polyvinyl alcohol, carboxymethylcellulose and methylcellulose, styrene- Generally used for coated paper such as butadiene copolymer, conjugated diene polymer latex of methyl methacrylate-butadiene copolymer, acrylic polymer latex, vinyl polymer latex such as ethylene-vinyl acetate copolymer, etc. Conventionally known adhesives can be used alone or in combination of two or more. In addition, the compounding quantity of an adhesive agent is adjusted in the range of 5-50 weight part with respect to 100 weight part of pigments, More preferably, it is 10-30 weight part.
[0025]
A cationic resin can be added to the coated layer for inkjet recording coated paper for the purpose of improving its water resistance and printing color density. In the present invention, it is particularly preferable to add to the alumina-containing layer. As the cationic resin in this case, for example, polyalkylene polyamines such as polyethylene polyamine and polypropylene polyamine, or derivatives thereof, acrylic resins having tertiary amino groups and quaternary ammonium groups, diacrylamines, and the like are appropriately used. Two or more kinds may be used in combination.
[0026]
The addition amount of the cationic resin is not particularly limited, but is adjusted in the range of 1 to 30% by weight, preferably 5 to 20% by weight with respect to the pigment. In addition, various auxiliary agents such as a dispersant, a thickener, an antifoaming agent, a colorant, an antistatic agent, and an antiseptic used in the production of general coated paper can be appropriately added.
[0027]
Thus, the composition for an undercoat layer composed of the above materials is generally adjusted to a solid content concentration of about 1 to 65% by weight, and has a basis weight of about 20 to 400 g / m. ² 2 to 50 g / m in dry weight on about a base paper ² , Preferably 5 to 20 g / m ² It is coated and dried by a coating apparatus such as a blade coater, an air knife coater, a roll coater, a brush coater, a Chanplex coater, a bar coater, or a gravure coater. Furthermore, if necessary, after the undercoat coating layer is dried, a smoothing process such as super calendering, brushing, and cast finishing can be performed.
[0028]
The base paper used as the support is not particularly limited, and acid paper or neutral paper used for general coated paper is appropriately used.
[0029]
The bulk density thus formed is 0.2 g / cm. ^Three Examples of the resin to be contained in the coating layer for casting provided on the following alumina-containing layer include a polymer obtained by polymerizing a monomer having an ethylenically unsaturated bond. That is, as a polymer obtained by polymerizing a monomer having an ethylenically unsaturated bond (hereinafter referred to as an ethylenic monomer), for example, methyl acrylate, ethyl acrylate, butyl acrylate, 2- Acrylic acid ester having 1 to 18 carbon atoms such as ethylhexyl acrylate, lauryl acrylate, 2-hydroxyethyl acrylate, glycidyl acrylate, methyl methacrylate, ethyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, glycidyl methacrylate Methacrylates having 1 to 18 alkyl groups such as styrene, α-methylstyrene, vinyltoluene, acrylonitrile, vinyl chloride, vinylidene chloride, vinyl acetate, vinyl propionate, acrylamide, N-methylolacrylamide, ethylene, It is a polymer obtained by polymerizing ethylenic monomers such as butadiene.
[0030]
In this case, the polymer in this case may be a copolymer using two or more kinds of ethylenic monomers in combination, or may be a substituted derivative of these polymers or copolymers. Incidentally, examples of the substituted derivative include, for example, a carboxylated one, or an alkali-reactive one. It is also possible to polymerize the monomer having an ethylenically unsaturated bond in the presence of colloidal silica and use it in the form of a complex by Si—O—R (R: polymer component) bond. . Further, a pigment such as colloidal silica can be added in an amount of, for example, about 200 parts by weight or less with respect to 100 parts by weight of the resin within a range that does not impair the glossiness and the recordability.
Although the particle size of colloidal silica is not particularly limited, the average particle size is preferably about 0.01 to 0.2 μm.
[0031]
The polymer (resin) contained in the coating layer for casting preferably has a glass transition point of 40 ° C. or higher. More preferably, it is about 50-100 degreeC.
[0032]
That is, in the production of conventional cast coated paper, in order to obtain an excellent surface gloss, the resin (polymer) in the cast coating composition is sufficiently formed during casting to obtain a high gloss. Was getting. However, in such a conventional method, the porosity of the surface of the cast coating layer is reduced, and as a result, the ink absorbability at the time of inkjet recording is lowered, and a cast coated paper having desirable inkjet recording suitability is obtained. It is often difficult.
[0033]
Therefore, it is preferable to use a polymer having a relatively high glass transition point and perform cast finishing in a state in which the polymer does not completely form a film in order to make the ink absorbability superior. . This effectively maintains the porosity of the cast coated paper surface and is excellent ink The cast coated paper which has the absorptivity of this and the outstanding glossy surface can be obtained.
[0034]
On the other hand, if the glass transition point of the polymer is low, the heat of the cast drum surface makes it easier to form a resin component than necessary, resulting in a decrease in the porosity of the cast coating layer surface, Although the gloss value is high, ink Absorbability may be reduced. Therefore, in the present invention, when producing cast coated paper, it is preferable to dry finish the cast coated layer under a temperature condition lower than the glass transition point of the resin contained in the cast coated layer.
[0035]
In addition, Cast coating layer Some pigments, dispersants, thickeners, antifoaming agents, colorants, charging agents used in general coated paper for printing and inkjet recording paper are used to adjust whiteness, viscosity, fluidity, etc. Various auxiliary agents such as an inhibitor and a preservative can be appropriately added.
[0036]
Cast coating solution containing the above-mentioned polymer on the coating surface of the undercoat coated paper, various known methods such as blade coater, air knife coater, roll coater, brush coater, chamber coater, bar coater, gravure coater, etc. While the coating layer is in the wet state as described above, it is pressed against the heated mirror drum and dried to perform the cast finish. In this case, the coating amount of the cast coating solution is 0.2 to 30 g / m in terms of dry solid content. ² Preferably 1-10 g / m ² It is.
In a preferred embodiment of the present invention, the cast paper is adjusted to an air permeability (JIS-P-8117) of 300 sec / 100 cc or less, more preferably 10 to 200 sec / 100 cc. A record is obtained. Further, the Gurley air permeability after forming the undercoat layer (ASTM-D-726 B method using a Gurley high pressure type air permeability tester) is preferably 30 seconds / 10 cc or less.
[0037]
The ink jet recording method of the present invention using the cast coated paper for ink jet recording thus obtained can be any system as long as the ink can be effectively detached from the nozzle and the ink can be applied to the recording medium as a projectile. In particular, the method described in Japanese Patent Application Laid-Open No. 54-59936 causes an abrupt volume change of the ink subjected to the action of thermal energy, and the ink is ejected from the nozzle by the action force caused by this state change. An ink jet recording method for discharging more effectively can be used.
[0038]
An example of an ink jet recording apparatus suitable for the ink jet recording method of the present invention will be described below. Examples of the head structure, which is the main part of the apparatus, are shown in FIGS. That is,
The head 13 is bonded to a heat generating head 15 (head is shown in the figure, but is not limited to this) used for thermal recording, such as a glass, ceramic or plastic plate having a groove 14 through which ink passes. Is obtained. The heating head 15 includes a protective film 16 formed of silicon oxide or the like, aluminum electrodes 17-1 and 17-2, a heating resistor layer 18 formed of nichrome or the like, a heat storage layer 19, and a substrate 20 with good heat dissipation such as alumina. It has become more.
[0039]
The ink 21 reaches the ejection orifice (fine hole) 22, and a meniscus 23 is formed by the pressure P.
[0040]
Now, when an electrical signal is applied to the electrodes 17-1 and 17-2, the region indicated by n of the heat generating head 15 rapidly generates heat, bubbles are generated in the ink 21 in contact therewith, and the meniscus 23 is generated by the pressure. Protrudes and ink 21 is ejected to form recording droplets 24 from the orifice 22 and fly toward the recording sheet 25. FIG. 3 shows an external view of a multi-head in which a large number of heads shown in FIG. 1 are arranged. The multi-head is manufactured by adhering a glass plate 27 having multi-grooves 26 and a heating head 28 similar to that described in FIG.
[0041]
1 is a cross-sectional view of the head 13 along the ink flow path, and FIG. 2 is a cross-sectional view taken along line AB in FIG.
[0042]
FIG. 4 shows an example of an ink jet recording apparatus in which such a head is incorporated. In FIG. 4, reference numeral 61 denotes a blade as a wiping member. One end of the blade 61 is held by a blade holding member to become a fixed end, and forms a cantilever. The blade 61 is disposed at a position adjacent to the recording area by the recording head, and in this example, is held in a form protruding in the moving path of the recording head. Reference numeral 62 denotes a cap, which is disposed at a home position adjacent to the blade 61 and has a configuration in which it moves in a direction perpendicular to the moving direction of the recording head and comes into contact with the ejection port surface to perform capping. Further, 63 is an ink absorber provided adjacent to the blade 61 and is held in a form protruding in the moving path of the recording head, like the blade 61. The blade 61, the cap 62, and the absorber 63 constitute a discharge recovery portion 64, and the blade 61 and the absorber 63 remove moisture, dust, and the like from the ink discharge port surface.
[0043]
65 has a discharge energy generating means, and a recording head for recording by discharging ink onto a recording medium facing the discharge port surface on which the discharge port is arranged. 66 is mounted with the recording head 65 to move the recording head 65. Carriage for performing. The carriage 66 is slidably engaged with the guide shaft 67, and a part of the carriage 66 is connected to a belt 69 (not shown) driven by a motor 68. As a result, the carriage 66 can move along the guide shaft 67, and the recording area by the recording head 65 and the area adjacent thereto can be moved.
[0044]
51 is a paper feed section for inserting a recording medium, and 52 is a paper feed roller driven by a motor (not shown). With these configurations, the recording medium is fed to a position facing the ejection port surface of the recording head, and is discharged through the discharge roller 53 as recording progresses.
[0045]
In the above configuration, when the recording head 65 returns to the home position due to the end of recording or the like, the cap 62 of the head recovery unit 64 is retracted from the moving path of the recording head 65, but the blade 61 protrudes into the moving path. . As a result, the ejection port surface of the recording head 65 is wiped. When the cap 62 is in contact with the protruding surface of the recording head 65 to perform capping, the cap 62 moves so as to protrude into the moving path of the recording head.
[0046]
When the recording head 65 moves from the home position to the recording start position, the cap 62 and the blade 61 are in the same position as the above-described wiping position. As a result, the protruding opening surface of the recording head 65 is wiped even during the movement.
[0047]
The above-mentioned movement of the recording head to the home position is not only at the end of recording or at the time of ejection recovery, but also to the home position adjacent to the recording area at a predetermined interval while the recording head moves the recording area for recording. The wiping is performed along with the movement.
[0048]
On the other hand, the ink used in the ink jet recording method of the present invention includes a dye for forming an image and a liquid medium for dissolving or dispersing the dye as essential components, and various dispersants and interfaces as required. It is prepared by adding an activator, a viscosity modifier, a specific resistance adjuster, a pH adjuster, an antifungal agent, a recording agent dissolution (or dispersion) stabilizer, and the like.
[0049]
Examples of the recording agent used in the ink include direct dyes, acid dyes, basic dyes, reactive dyes, edible dyes, disperse dyes, oil-based dyes, and various pigments. be able to. The content of such a coloring matter is determined depending on the type of liquid medium component, the characteristics required for the ink, etc., but in the case of the ink in the present invention, the blending in the conventional ink, that is, There is no problem in particular when it is used in a proportion of about 0.1 to 20% by weight.
The alumina having a specific bulk density used in the present invention is preferably a cationic one. In this case, it is particularly preferable to use a direct dye or an acid dye in terms of color development and light resistance.
[0050]
The ink used in the present invention is a liquid solvent obtained by dissolving or dispersing the pigment as described above, and contains water or water and a water-soluble organic solvent containing a polyhydric alcohol having an effect of preventing drying of the ink. Is used.
The preferred surface tension range of the yellow, cyan, and magenta color inks used in the present invention is in the range of 25 to 40 dyne / cm. This range is effective for suppressing ink bleeding between different colors.
[0051]
【Example】
EXAMPLES The present invention will be described more specifically with reference to the following examples. However, the present invention is not limited to these examples. Moreover, unless otherwise indicated, the part and% in an example show a weight part and weight%, respectively.
[0052]
Example 1
High-purity alumina as a pigment (manufactured by Sumitomo Chemical Co., Ltd., trade name: AKP-G015, scaly alumina, bulk density 0.07 g / cm ^Three , Specific surface area 150m ² / G) 100 parts, 15 parts of polyvinyl alcohol as adhesive, 8 parts of polyethylene polyamine resin as cationic resin, condensate resin of dicyandiamide and formalin (trade name: Neofix FY / manufactured by Nikka Chemical Co., Ltd.) As a dispersant, 10 parts of sodium polyphosphate was added to prepare an undercoat coating solution having a solid content of 15%. This undercoat coating solution is 100 g / m2 ² 8g / m in dry weight on the base paper ² Then, it was coated with an air knife coater and dried to obtain an undercoat base paper.
[0053]
On the other hand, as a cast coating solution, for a cast having a solid content concentration of 30% comprising 40 parts of a styrene-2-methylhexyl acrylate copolymer having a glass transition point of 80 ° C., 60 parts of colloidal silica, and 2 parts of calcium stearate as a release agent. A coating solution was prepared. After coating this coating liquid on the above-mentioned base base paper using a roll coater, it is immediately pressed against a mirror drum having a surface temperature of 85 ° C., dried and then released to obtain a cast coated paper for inkjet recording. It was. The coating amount at this time is 7 g / m in terms of solid weight. ² Met.
[0054]
Example 2
In Example 1, a cast coated paper for inkjet recording was obtained in the same manner as in Example 1 except that the surface temperature of the mirror drum was changed from 85 ° C. to 70 ° C. in obtaining the cast coated paper. The coating amount at this time is 7 g / m in terms of solid weight. ² Met.
[0055]
Example 3
A casting coating solution having a solid content concentration of 35% comprising 100 parts of a styrene-methyl acrylate copolymer having a glass transition point of 50 ° C. as a casting coating solution and 5 parts of ammonium oleate as a release agent was prepared. After coating this coating solution on the base base paper obtained in Example 1 using a roll coater, it was immediately pressed against a mirror drum having a surface temperature of 60 ° C., dried and released, and cast coating for inkjet recording. A paper was obtained. The coating amount at this time is 3 g / m in terms of solid content. ² Met.
[0056]
Example 4
The cast coating solution has a solid content concentration of 100 parts of a styrene-methyl acrylate copolymer and colloidal silica (weight ratio 50:50) having a glass transition point of 70 ° C. and 3 parts of ammonium oleate as a release agent. A 40% casting coating solution was prepared. After coating this coating solution on the base base paper obtained in Example 1 using a roll coater, it was immediately pressed against a heated mirror drum having a surface temperature of 65 ° C., dried, released, and used for inkjet recording. A cast coated paper was obtained. The coating amount at this time is a solid content weight of 6 g / m. ² Met.
[0057]
Example 5
As a pigment, high-purity alumina (manufactured by Sumitomo Chemical Co., Ltd., trade name: AKP-G030, scaly alumina, bulk density 0.07 g / cm ^Three , Specific surface area 250m ² / G) 90 parts, 10 parts of amorphous silica, 15 parts of polyvinyl alcohol as adhesive, 8 parts of polyethylene polyamine resin as cationic resin, condensate resin of dicyandiamide and formalin (trade name: Neofix FY / Nikka) Chemical Co., Ltd. (10 parts) and 0.5 parts of sodium polyphosphate as a dispersant were added to prepare a coating solution for undercoating of a solid content concentration of 15%. This undercoat coating solution is 100 g / m2 ² 8g / m in dry weight on the base paper ² Then, it was coated with an air knife coater and dried to obtain an undercoat base paper.
[0058]
Next, the coating liquid for casting used in Example 1 was coated on this undercoat base paper, and a cast coated paper for inkjet recording was obtained in the same manner as in Example 1. The coating amount at this time is 7 g / m in terms of solid weight. ² Met.
[0059]
Example 6
In obtaining cast coated paper in Example 1, high-purity alumina (manufactured by Sumitomo Chemical Co., Ltd., trade name: AKP-G015, bulk density 0.07 g / cm ^Three , Specific surface area 150m ² / G) 100 parts of high-purity alumina (manufactured by Sumitomo Chemical Co., Ltd., trade name: AKP-G, plate-like alumina, bulk density 0.18 g / cm) ^Three , Specific surface area 150m ² / G) A cast coated paper for inkjet recording was obtained in the same manner except that the amount was 100 parts.
[0060]
Comparative Example 1
MgCO as a pigment for undercoating liquid _Three (Bulk density 0.26 g / cm ^Three , Specific surface area 50m ² / G) 70 parts, heavy calcium carbonate (bulk density 1.1 g / cm ^Three , Specific surface area 3.0m ² / G) 30 parts, 5 parts of oxidized starch as an adhesive, 10 parts of styrene-butadiene copolymer latex, dicyandiamide and formalin condensate resin as a cationic resin (trade name: Neofix FY / manufactured by Nikka Chemical Co., Ltd.) ) 5 parts, 0.4 part of sodium polyphosphate as a dispersant was added to prepare a coating solution for undercoating of 30% solid content. This undercoat coating solution is 100 g / m2 ² 15 g / m in dry weight on a base paper ² Then, it was coated with a blade coater and dried to obtain an undercoat base paper.
[0061]
Next, the coating liquid for casting used in Example 1 was coated on this undercoat base paper, and a cast coated paper for inkjet recording was obtained in the same manner as in Example 1. The coating amount at this time is a solid content weight of 6 g / m. ² Met.
[0062]
Comparative Example 2
High-purity alumina (manufactured by Sumitomo Chemical Co., Ltd., trade name: AKS-G, plate-like alumina, bulk density 0.4 g / cm) ^Three , Specific surface area 150m ² / G) 100 parts, 15 parts of polyvinyl alcohol as an adhesive, 8 parts of polyethylene polyamine resin (trade name: Neofix RP-70 / manufactured by Nikka Chemical Co., Ltd.) as a cationic resin, sodium polyphosphate as a dispersant 0.4 parts was added to prepare an undercoat coating solution having a solid concentration of 20%. This undercoat coating solution is made up of 80 g / m2 ² 7g / m in dry weight on the base paper ² Then, it was coated with an air knife coater and dried to obtain an undercoat base paper.
[0063]
The casting coating solution used in Example 1 was coated on this base base paper, and a cast coated paper for inkjet recording was obtained in the same manner as in Example 1. The coating amount at this time is 7 g / m in terms of solid weight. ² Met.
[0064]
Comparative Example 3
Amorphous silica (bulk density 0.05g / cm ^Three , Specific surface area 250m ² / G) 100 parts, 15 parts of polyvinyl alcohol as an adhesive, 8 parts of diacrylamine acrylamide resin (trade name: Sumirez Resin 1001 / Sumitomo Chemical Co., Ltd.) as a cationic resin, sodium polyphosphate 0 as a dispersant .4 parts were added to prepare a coating solution for undercoating of a solid content concentration of 30%. This coating solution is 80 g / m 2 ² 6 g / m by dry weight on a base paper ² Then, it was coated with a blade coater and dried to obtain an undercoat base paper. The casting coating liquid used in Example 1 was coated on this base base paper, and a cast coated paper for inkjet recording was obtained by the same method as in Example 1. The coating amount at this time is 5 g / m in terms of solid content. ² Met.
[0065]
Comparative Example 4
In Comparative Example 2, 100 parts of high-purity alumina (manufactured by Sumitomo Chemical Co., Ltd., trade name: AKS-G) in the undercoat coating solution was replaced with 100 parts of high-purity alumina (manufactured by Sumitomo Chemical Co., Ltd., trade name: AKP-). 3000, plate-like alumina, bulk density 0.7g / cm ^Three , Specific surface area 6m ² / G) A cast coated paper for inkjet recording was obtained in the same manner except that the amount was 100 parts.
[0066]
Comparative Example 5
In Comparative Example 2, 100 parts of high-purity alumina (AKS-G manufactured by Sumitomo Chemical Co., Ltd.) in the undercoat coating solution was prepared by using alumina obtained by treating bauxite with hot caustic soda (manufactured by Sumitomo Chemical Co., Ltd., Product name: A-11, plate alumina, bulk density 1.1 g / cm ^Three , Specific surface area 150m ² / G) A cast coated paper for inkjet recording was obtained in the same manner except that the amount was 100 parts.
[0067]
Comparative Example 6
As a pigment, kaolin (bulk density 0.85 g / cm ^Three , Specific surface area 20m ² / G) 50 parts, light calcium carbonate (bulk density 0.8 g / cm ^Three , Specific surface area 11.5m ² / G) 50 parts, 5 parts of oxidized starch as an adhesive, 20 parts of styrene-butadiene copolymer latex, 0.5 part of sodium polyphosphate as a dispersant are added, and an undercoat coating solution of 50% solid content is added. Prepared. This undercoat coating solution is 100 g / m2 ² Base paper with a dry weight of 12g / m ² Then, it was coated with an air knife coater and dried to obtain an undercoat base paper.
[0068]
Also, a casting coating solution having a solid content concentration of 45% comprising 100 parts of kaolin, 10 parts of casein, 10 parts of styrene-methyl methacrylate having a glass transition point of 30 ° C., and 10 parts of calcium stearate as a release agent. After coating with a roll coater on the above base base paper, it was immediately pressed against a mirror drum having a surface temperature of 85 ° C., dried, and released to obtain a cast coated paper for inkjet recording. . The coating amount at this time is 12 g / m in terms of solid weight. ² Met.
[0069]
The results of blank gloss, ink jet recording suitability, and weather resistance of the cast coated paper thus obtained are summarized in Table 1.
In addition, about said evaluation, it evaluated by the following methods.
[0070]
(White paper gloss)
It measured according to JIS-P8142.
[0071]
(Absorptivity of ink for inkjet recording)
Yellow, cyan, and magenta color inks containing a direct dye and having a surface tension of 35 dyne / cm were mounted on a bubble jet printer BJC600 (trade name) manufactured by Canon to perform printing, and the quick drying property of the ink was visually evaluated.
A: The ink is absorbed within 1 second after printing, and the boundary between the green portion which is a mixed color portion of magenta and cyan and the red portion which is a mixed color portion of yellow and magenta is clear.
○: Ink is absorbed within 5 seconds of printing, and the boundary between the green part and the red part is clear.
Δ: Ink absorption exceeds 5 seconds after printing, but the boundary between the green part and the red part is clear.
X: Ink absorption exceeds 20 seconds, and the boundary between the green part and the red part is slightly unclear.
XX: Absorption of ink exceeds 1 minute, boundary between green and red is unclear, and boundary between magenta, cyan, and yellow is slightly unclear.
[0072]
(Color development after ink-jet recording ink recording)
Printing was performed with the above-described bubble jet printer BJC600, and the ink density was visually evaluated. This evaluation reflects the sharpness in color recording.
○: Excellent color density.
Δ: The color density is slightly thin.
[0073]
(Weatherability)
The sample was left at room temperature for 3 months, and the decrease in print density was visually determined.
◯: Good with no decrease in print density.
Δ: Decrease in print density is observed.
X: Significant decrease in print density.
[0074]
[Table 1]

[0075]
【The invention's effect】
As is clear from the results in Table 1, the cast coated paper of the present invention was excellent in surface gloss, ink jet recording suitability and weather resistance, and could be produced efficiently.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a head portion of an ink jet recording apparatus.
FIG. 2 is a cross-sectional view of a head portion of an ink jet recording apparatus.
3 is an external perspective view of a head in which the head shown in FIG.
FIG. 4 is a perspective view illustrating an example of an ink jet recording apparatus.
FIG. 5 illustrates a method for producing alumina by a hydrolysis method of aluminum alkoxide.
[Explanation of symbols]
13: Head
14: Groove for ink
15: Heat generation head
16: Protective film
17-1: Aluminum electrode
17-2: Aluminum electrode
18: Heating resistor layer
19: Heat storage layer
20: Substrate
21: Ink
22: Orifice
23: Meniscus
24: Recording droplet
25: Recording sheet
26: Multi groove
27: Glass plate
28: Heat generation head
51: Paper feed unit
52: Paper feed roller
53: Paper discharge roller
61: Blade
62: Cap
63: Ink absorber
64: Discharge recovery section
65: Recording head
66: Carriage
67: Guide shaft
68: Motor
69: Belt

Claims (6)

A base paper is provided with a coating layer containing alumina and an adhesive having a bulk density (JIS H-1902) of 0.04 to 0.2 g / cm ³ , and the coating layer has an ethylenically unsaturated bond. While the cast coating layer formed by polymerizing the monomer and containing a resin containing a resin having a glass transition point of 40 ° C. or higher is in a wet state, it is pressed against the heated mirror drum. A method for producing a cast coated paper for inkjet recording, which is dried and finished. The method for producing a cast coated paper for ink jet recording according to claim 1, wherein the alumina has a BET specific surface area of 1.0 to 200 m ² / g. A base paper is provided with a coating layer containing alumina and an adhesive having a bulk density (JIS H-1902) of 0.04 to 0.2 g / cm ³ , and the coating layer has an ethylenically unsaturated bond. A cast coated paper for inkjet recording, which is obtained by casting a layer obtained by polymerizing a monomer and coating a coating solution containing a resin having a glass transition point of 40 ° C. or higher . The cast coated paper for ink jet recording according to claim 3 , wherein the alumina has a BET specific surface area of 1.0 to 200 m ² / g. An ink jet recording method for forming an image by ejecting water-based ink from fine holes on the cast coated paper for ink jet recording according to claim 3 . The ink jet recording method according to claim 5, wherein the ink is ejected by applying thermal energy to the water-based ink.

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