JP4041664B2 - Inkjet recording sheet manufacturing method - Google Patents

Description

【０１１３】
上記表１の結果から、含水率５００％の塗膜に対する乾燥を、乾燥風の膜面風速、乾燥風温度及び膜面温度を本発明に規定する条件で行った実施例１〜６では、高速生産が行え、しかも得られたインクジェット記録用シート（１）及び（３）〜（５）は色材受容層のひび割れや光沢ムラ等の発生を伴うこともなかった。即ち、生産性の向上が図れ、安価で品質の良好なインクジェット記録用シートを製造することができた。また、負圧型ノズルを用いた場合（実施例３〜５）が乾燥ムラの点でより良好であった。
一方、本発明に規定する乾燥条件とせずに得たインクジェット記録用シート（７）〜（１２）では、ひび割れ及び光沢ムラを生じてしまい、生産性の向上を達成することはできなかった。
【０１１４】
（参考例１〜６）
−色材受容層用塗布液Ｂの調製−
下記組成中の下記(1)〜(3)を混合し、高速回転式コロイドミル（クレアミックス、エム・テクニック（株）製）を用いて、回転数１００００ｒｐｍで２０分間分散させた後、下記(4)〜(8)を含む溶液を加え、更に回転数１００００ｒｐｍで２０分間再分散して、色材受容層塗布液Ｂを調製した。
シリカ微粒子と水溶性樹脂との質量比（ＰＢ比／(1)：(4)）は、４．５：１であり、色材受容層塗布液ＢのｐＨは３．５（酸性）であった。
【０１１５】
〔色材受容層塗布液Ｂの組成〕
(1)気相法シリカ微粒子（無機顔料微粒子） …１０．０部
（平均一次粒子径７ｎｍ；レオロシールＱＳ３０、（株）トクヤマ製）
(2)イオン交換水 …５１．７部
(3)ＰＡＳ−Ｍ−１（分散剤；日東紡（株）製） … ０．８３部
(4)ポリビニルアルコール８％水溶液（水溶性樹脂） …２７．８部
（ＰＶＡ１２４、（株）クラレ製、鹸化度９８．５％、重合度２４００）
(5)ジエチレングリコールモノブチルエーテル … ０．７２部
(6)ポリオキシエチレンラウリルエーテル（界面活性剤） … １．２部
（エマルゲン１０９Ｐ(１０％)、花王（株）製、ＨＬＢ値１３．６）
(7)イオン交換水 …３０．７４部
(8)ホウ酸 … ０．０９部
【０１１６】
−インクジェット記録用シートの作製−
上記作製した支持体のオモテ面にコロナ放電処理を行った後、上記より得た色材受容層塗布液Ｂ（固形分濃度１０％）を、該オモテ面にスライドビード塗布法で塗布量が２００ｍｌ／ｍ²となるように塗布し（塗布工程）、塗布された塗膜の含水率が５００％になるまで熱風乾燥機にて６０℃（風速３〜８ｍ／ｓｅｃ）の熱風で乾燥させた。この期間、塗膜は恒率乾燥速度を示した（恒率乾燥工程）。
その後、下記組成の架橋剤溶液Ｂを、ナイフコーターを用いて塗布量２０ｇ／ｍ²となるように前記塗膜の表面に塗工し、下記表２に示す乾燥条件にしたがって、更に４０〜１４０℃の熱風で４０秒間乾燥させた（乾燥工程）。
以上より、乾燥膜厚２０μｍの色材受容層が設けられたインクジェット記録用シート（ａ）〜（ｆ）を得た。
【０１１７】
〔架橋剤溶液Ｂの組成〕
・硼酸（６％；架橋剤） …２５部
・ＰＡＡ−１０Ｃ（１０％）水溶液 …２０部
（媒染剤；日東紡（株）製）
・イオン交換水 …５２．８部
・塩化アンモニウム（表面ｐＨ調整剤） … ０．２部
・ポリオキシエチレンラウリルエーテル（界面活性剤） … ２部
（エマルゲン１０９Ｐ(１０％)、花王（株）製、ＨＬＢ値１３．６）
【０１１８】
上記より得たインクジェット記録用シート（ａ）〜（ｆ）の各々について、前記実施例と同様の評価を行った。評価結果は下記表２に示す。
【０１１９】
【表２】

【０１２０】
上記表２の結果から、架橋剤溶液付与後、塗膜の膜面温度を３０〜４５℃として乾燥を行って得たインクジェット記録用シート（ｂ）〜（ｅ）では、ひび割れ及び乾燥ムラの発生がなく良好な面状が得られた。一方、膜面温度４５℃を超える場合（参考例１）では膜面にひび割れが生じ、２５℃未満の場合（参考例６）では乾燥を完了し得なかった。
【０１２１】
【発明の効果】
本発明によれば、インク受容性能等のインクジェット記録用シートに要求される諸特性を有し、色材受容層のひび割れや光沢ムラ等の発生を招来することなく生産性（生産効率）の向上が図れ、低コスト化の可能なインクジェット記録用シートの製造方法を提供することができる。
【図面の簡単な説明】
【図１】 スリットノズルを備えるドライヤーの構成例を示す概略図である。
【図２】 負圧型ノズルを備えるフロータードライヤーの構成例を示す概略図である。
【図３】 (ａ)は正圧型ノズルをウェブの両側に配置したフロータードライヤーの構成例を、(ｂ)は正圧型ノズルをウェブの片側に配置したフロータードライヤーの構成例を示す図である。
【符号の説明】
１…スリットノズル
２…支持体上の塗膜面
３…ローラ
４…塗膜が設けられた支持体（ウェブ）
５ａ，５ｂ，５ｃ…ノズル
６…正圧型ノズル[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ink jet recording sheet which is a recording material suitable for ink jet recording using a liquid ink such as a water-based ink or an oil-based ink, or a solid ink which is solid at room temperature and is melt-liquefied and used for printing. It relates to the manufacturing method.
[0002]
[Prior art]
Inkjet recording methods are widely used in offices and so-called home use because they can be recorded on various types of recording materials, the hardware (device) is relatively inexpensive, compact, and quiet. It has been used.
Recently, with the development of inkjet printers (hardware), higher resolution has been achieved, and there is a situation where higher-quality image output is required.
[0003]
The characteristics required for a recording sheet for ink jet recording are generally (1) high ink absorption speed, (2) no ink dot bleeding, (3) good graininess, (4) High color density (color developability), (5) High chroma (no dullness), (6) Light resistance and water resistance of the printed area, (7) Whiteness of the unprinted area (9) In addition to ink receiving performance such as (8) good storage stability of the recording sheet (long-term storage and no yellowing coloration), (9) good deformation resistance and good dimensional stability (Curl must be sufficiently small), (10) Good hard runability, and (11) Photo glossy paper used for the purpose of obtaining so-called photographic-like high-quality recorded matter includes glossiness, Surface smoothness, photographic paper-like texture similar to silver halide photography It is necessary to satisfy all of these requirements.
However, as a basic performance, it is important that the colorant-receiving layer does not crack, and even a recording sheet that satisfies the above-mentioned characteristics deteriorates quality due to the occurrence of cracks, leading to a reduction in commercial value. Further, when drying unevenness occurs during drying, appearance such as glossiness is also impaired.
[0004]
In recent years, there has been a tendency for the demand for recording sheets for ink jets to increase, and various techniques have been studied and proposed for producing recording sheets that satisfy the above-mentioned characteristics and have basic performance with high production efficiency and low cost. Yes.
In the ink jet recording sheet, the colorant receiving layer formed on the support is formed from inorganic fine particles and a water-soluble resin so as to have a high porosity. Small and high content. Therefore, as shown in JP-A-11-115308, JP-A-2001-10207, etc., when a coating liquid containing a material for forming such a colorant receiving layer is applied, It is known that cracks occur during the drying of the membrane.
In addition, it has been found that cracks in the colorant-receiving layer are likely to occur when it is dried at a relatively high temperature in order to shorten the drying time after application, in particular. Moreover, when drying is not performed uniformly, drying unevenness (gloss unevenness) also occurs.
[0005]
For example, in Japanese Patent Application Laid-Open No. 2001-10207, a method of drying the coating film with a film surface temperature of 30 ° C. or lower during the drying process in which the moisture content of the applied coating is 200 to 30%, the moisture content of the coating is During drying at 1000 to 500%, the film surface temperature is 20 ° C. or less and the film surface wind speed is 30 m / sec or less, and the film surface temperature is 1000 to 500% during drying. And a method of using a slit nozzle in a drying apparatus is disclosed. However, these are all methods of drying with low-temperature air over a long period of time, and although a good surface shape can be obtained, it is difficult to improve productivity because the production speed is low and it is difficult to increase productivity. A problem arises in that the production cost increases.
[0006]
On the other hand, in Japanese Patent Application Laid-Open No. 11-115308, as a method for making it difficult for cracks to occur during coating and drying, a coating solution containing inorganic fine particles and a water-soluble resin is coated on a support, and simultaneously with the coating or coating. There has been proposed a method of applying and curing a solution containing a cross-linking agent capable of cross-linking the water-soluble resin before the applied coating film exhibits a reduced rate of drying.
In the above method, although the drying temperature is higher than that of the conventional method of mixing and applying inorganic fine particles and water-soluble resin and a crosslinking agent, it is generally used as a dryer for coated paper in production. When a pressure type floater dryer or a single-side slit nozzle type dryer is used, there is a problem that cracks and uneven gloss are likely to occur, which is insufficient in terms of improving production efficiency.
[0007]
[Problems to be solved by the invention]
As described above, an inkjet recording sheet that has various properties required for the above-described inkjet recording sheet but also satisfies basic performance such as no cracks and uneven glossiness is manufactured at high speed and with high production efficiency. The technology that can be used has not been established yet.
Accordingly, the present invention solves the above-mentioned conventional problems, has various properties required for an ink jet recording sheet such as ink receiving performance, and causes the occurrence of cracks in the colorant receiving layer and uneven gloss. It is an object of the present invention to provide a method for manufacturing an inkjet recording sheet that can improve productivity (production efficiency) and reduce costs, and to achieve the object.
[0008]
[Means for Solving the Problems]
In the drying process in which the coating film before the solution containing the crosslinking agent and the mordant is applied is in a fluid state, when drying is performed by supplying a drying air at a low speed and a high temperature, cracks, gloss unevenness, etc. are generated. This is based on the fact that the drying efficiency can be improved without causing odor.
Means for solving the above-mentioned problems are as follows. That is,
[0009]
  <1> In a method for producing an ink jet recording sheet having a colorant receiving layer formed by applying and drying a coating liquid containing inorganic pigment fine particles and a water-soluble resin on a support, the water content after coating is 1000 to 500%. For the coating film ofThe drying is divided into the first half, the film surface wind speed of the drying air in the first half of drying is 10 m / sec or less, and the film surface wind speed of the drying air in the second half of drying is made larger than the film surface wind speed of the drying air in the first half of drying.And a drying air temperature is set to a temperature exceeding 30 ° C., and drying is performed at a film surface temperature exceeding 20 ° C.
  <2> The method for producing an inkjet recording sheet according to <1>, wherein at least one of a dryer including a slit nozzle having a nozzle tip located at a distance of 20 mm or more from the film surface and a floater dryer including a negative pressure type nozzle is used. It is.
[0010]
  <3> A coating liquid containing inorganic pigment fine particles and a water-soluble resin is applied onto the support, and the water content is 1000 to 200% during the drying after the application and before the reduced rate drying rate is exhibited. The method for producing an inkjet recording sheet according to <1> or <2>, wherein a solution containing a crosslinking agent capable of crosslinking the water-soluble resin and a mordant is applied to the coating film.
  <4> A coating liquid containing inorganic pigment fine particles and a water-soluble resin is applied on a support, and the water content is 1000 to 200% during the drying after the application and before the reduced rate of drying is exhibited. <1>, after applying a solution containing a crosslinking agent capable of crosslinking the water-soluble resin and a mordant to the coating film, and drying the coating film to which the solution has been applied at a film surface temperature of 25 to 50 ° C. It is a manufacturing method of the sheet | seat for inkjet recording in any one of <3>.
  <5> The drying air temperature in the first half of the drying is 30 ° C. or higher, and the drying air temperature in the second half of the drying is lower than the drying air temperature in the first half of the drying. A method for producing an ink jet recording sheet according to claim 1.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
  In the method for producing an inkjet recording sheet of the present invention, the coating film having a moisture content of 1000 to 500% after coating is dried.The drying is divided into the first half and the film surface speed of the drying air in the first half of the drying is 10 m / sec or less, and the film surface speed of the drying air in the second half of the drying is made larger than the film surface speed of the drying air in the first half of the drying.The drying air temperature is set to a temperature exceeding 30 ° C., and the film surface temperature is set to a temperature exceeding 20 ° C.
  Hereafter, the manufacturing method of the sheet | seat for inkjet recording of this invention is explained in full detail.
[0012]
[Method for producing inkjet recording sheet]
  In the method for producing an inkjet recording sheet of the present invention, a colorant receiving layer is formed on a support by applying and drying a coating liquid containing inorganic pigment fine particles and a water-soluble resin, and other layers as necessary. Is formed.
-Formation of colorant receiving layer-
  The color material receiving layer according to the present invention is applied on a support by applying a coating liquid containing inorganic pigment fine particles and a water-soluble resin (hereinafter sometimes referred to as “color material receiving layer coating liquid”). In the drying process, drying of the coating film in a state of water content of 1000 to 500%,The drying is divided into the first half and the film surface speed of the drying air in the first half of the drying is 10 m / sec or less, and the film surface speed of the drying air in the second half of the drying is made larger than the film surface speed of the drying air in the first half of the drying.The drying air temperature is set to a temperature exceeding 30 ° C., and the film surface temperature is set to a temperature exceeding 20 ° C.
[0013]
The moisture content here refers to the ratio (%) of moisture (mass) to the solid content (mass) in the coating film to which the colorant-receiving layer coating solution is applied. For example, the solid content coating amount is 20 g / m.²The amount of water contained in this is 200 g / m²Then, the water content in this case is set to 1000%.
The film surface refers to the surface of the coating film on which the colorant-receiving layer coating solution is applied, and the film surface wind speed is measured at the position of the support (web) on which the coating film is formed. The wind speed.
[0014]
When drying is started after application of the colorant-receiving layer coating solution, the coating film on the support is gradually dried, and the moisture content of the coating film reaches 1000 to 500%. In the stage of the fluid state at the initial stage of drying, in this state, the speed of the drying air supplied to the coating film surface (film surface air speed) is reduced to 10 m / sec or less, and drying is performed with high-temperature air exceeding 30 ° C. That is, the coating film having a water content of 500% or more is dried under the above conditions.
In addition, the drying until the coating film water content reaches 1000% can be performed without any particular limitation.
[0015]
When the film surface wind speed exceeds 10 m / sec, the surface of the coating film is dried faster than the inside, thereby deteriorating the drying efficiency and causing cracks in the coating film and uneven gloss, which is not preferable. Among the film surface wind speeds (10 m / sec or less), 2 to 5 m / sec is particularly preferable in terms of ensuring drying efficiency. Further, the drying performed at this time (constant rate drying) may be performed in half in the first and second half. In this case, the film surface wind speed in the first half is 1 to 3 m / sec, and the film surface wind speed in the second half is 3 m / sec. -5 m / sec is preferable. An embodiment in which the film surface wind speed in either the first or second half is 10 m / sec or less is preferable, but an embodiment in which only the film surface temperature in the first half is 10 m / sec or less may be used.
As described above, as a means for lowering the film surface wind speed, a method using a slit nozzle in which the distance between the coating film surface and the nozzle tip is increased to 20 mm or more is preferable as described later.
[0016]
Further, when the drying air temperature is low-temperature drying of less than 30 ° C., it takes too much drying time and is inferior in productivity. Among the drying air temperatures (30 ° C. or higher), 35 to 150 ° C. is preferable, and 40 to 125 ° C. is more preferable.
Furthermore, it is desirable that the drying performed at this time (constant rate drying) is performed in half in the first and second half, and it is more preferable that the first half is dried as high as possible and the second half is dried at low temperature. At this time, the drying air temperature in the first half is more preferably 70 to 125 ° C, and the drying air temperature in the second half is more preferably 40 to 90 ° C. In this case, the drying air temperature is preferably 30 ° C. or higher in both the first and second half, but the embodiment may be such that the drying air temperature only in the first half is 30 ° C. or higher.
[0017]
When drying with the film surface wind speed and drying air temperature within the above ranges, the film surface temperature of the coating film is further set to a temperature exceeding 20 ° C. In so-called low-temperature drying in which the film surface temperature is 20 ° C. or less, drying takes a long time and sufficient productivity cannot be obtained. Moreover, as an upper limit of film surface temperature, it is desirable that it is 50 degrees C or less. When the film surface temperature exceeds 50 ° C., cracks and drying unevenness (gloss unevenness; hereinafter, also referred to as “gloss unevenness”) may occur in the coating film. Among the above ranges, 30 to 40 ° C. is particularly preferable.
Moreover, when drying is carried out in half in the first half as described above, the film surface temperature in the first half is preferably 30 to 40 ° C., and the film surface temperature in the second half is preferably 20 to 35 ° C. In this case, an aspect in which the film surface temperature in both the first and second half exceeds 20 ° C. is preferable, but an aspect in which only the film surface temperature in the first half exceeds 20 ° C. may be employed.
[0018]
As described above, the drying performed on the coated film having a moisture content of 1000 to 500% is at least one of a dryer having a slit nozzle (see FIG. 1) and a floater dryer having a negative pressure type nozzle (see FIG. 2). It can carry out suitably using.
[0019]
The dryer provided with the slit nozzle can be appropriately selected from dryers having a nozzle tip formed in a slit shape, and the slit nozzle is a distance between the tip of the nozzle 1 and the film surface 2 of the coating film as shown in FIG. It can be used by being disposed at a position where A is 20 mm or more. The nozzle 1 may be provided at least on the side where the coating film of the support is formed (single-sided slit nozzle), and may be provided on the opposite side (double-sided slit nozzle).
The distance A is preferably closer from the viewpoint of increasing the drying speed. However, in the present invention, by setting the distance A within the above range, the film surface wind speed of the drying air is preferably 10 m / sec or less. be able to. Among these, the distance A between the film surface and the nozzle tip is particularly preferably 30 to 50 mm. The direction of the drying air supplied from the slit nozzle is not particularly limited, and is preferably substantially parallel to the normal direction of the film surface of the coating film.
An embodiment using a perforated plate nozzle instead of the slit nozzle is also suitable.
[0020]
A plurality of slit nozzles 1 are preferably arranged. In this case, the slit interval B (see FIG. 1) is preferably 200 mm or less, and particularly preferably 50 to 200 mm. If the distance exceeds 200 mm, the distribution of the heat transfer coefficient in the longitudinal direction of the coating film may not be uniform, and drying unevenness may not be sufficiently prevented.
In addition, when using the dryer provided with a slit nozzle or a perforated plate nozzle, as shown in FIG. 1, it is preferable that the support body in which the coating film 2 was provided is supported by the roll 3 grade | etc.,.
[0021]
Depending on the location of the dryer and the surface state of the support where the coating film is not provided, it may be desired to handle the support (web) on which the coating film is formed without contact. A floater dryer equipped with a negative pressure type nozzle is suitable.
The floater dryer provided with the negative pressure type nozzle may be configured as shown in FIG. 2, for example, while applying tension to the support (web) 4 on which the coating film is formed in parallel with the conveying direction. The drying air can be supplied along the web 4 from the nozzles 5a to 5c. That is, a weak negative pressure area is formed between the nozzle and the web with respect to the positive pressure area to which the drying air is supplied, and the web can be stabilized at a certain distance from the carrier surface and dried without contact. In this configuration, high-speed drying air is not locally supplied, and the coating surface is not dried more rapidly than the inside, so that the heat in the longitudinal direction of the coating It is difficult for the transmission rate distribution to occur, and the drying can be performed satisfactorily without causing uneven drying and cracking.
There is no restriction | limiting in particular as a floater dryer provided with the said negative pressure type nozzle, It can select from a well-known thing suitably and can be used.
[0022]
On the other hand, in a dryer having a positive pressure type nozzle 6 as shown in FIGS. 3A to 3B among the floater dryers, a strong jet is generally generated from the membrane surface substantially parallel to the normal direction of the web 4. Since the contact is from 5 to 15 mm close, this causes an uneven distribution of heat transfer coefficient, that is, a distribution of the drying speed in the longitudinal direction of the coating film, which tends to cause drying unevenness and cracks, and performs drying well. There are times when you can't.
[0023]
Drying performed on the coating film having a moisture content of 1000 to 500% after coating may be performed by dividing it into the first and second half. For example, a slit nozzle or a perforated plate nozzle is used in the first half of drying, and a negative pressure type nozzle is used in the second half of drying. For example, the drying form may be changed in the first and second half.
[0024]
In the present invention, the colorant receiving layer can be most suitably formed according to the following embodiment.
That is, a mode according to the WET ON WET method (WOW method) in which a mordant and a cross-linking agent are introduced in the process of applying a solution containing a cross-linking agent and a mordant, that is, inorganic pigment fine particles and a water-soluble resin on a support. The water-soluble resin is applied to a coating film having a water content of 1000 to 200% in the course of drying after coating, and before the coating liquid (coloring material receiving layer coating liquid) is dried, and before the reduced rate drying rate is exhibited. It is an embodiment obtained by applying a solution containing a crosslinking agent capable of crosslinking the resin and a mordant (hereinafter sometimes referred to as a “crosslinking agent solution”) and crosslinking and curing the coating film provided with the crosslinking agent solution. .
Here, the coating film having a water content of 1000 to 200% refers to a coating film before being provided with a crosslinking agent solution in the course of constant rate drying, which does not show a decreasing rate drying rate of the coating film. Is performed at a film surface wind speed of 10 m / sec or less, a drying air temperature exceeding 30 ° C., and a film surface temperature exceeding 20 ° C. Is preferred.
[0025]
As described above, in the present invention, the water resistance of the colorant receiving layer can be improved by simultaneously applying the mordant together with the crosslinking agent. That is, when the mordant is added directly to the colorant-receiving layer coating solution, the mordant is cationic, and thus may cause aggregation in the presence of inorganic pigment fine particles having an anionic charge on the surface, such as silica. However, if a solution containing a mordant and a colorant-receptive layer coating solution are prepared independently and applied individually, there is no need to consider agglomeration of inorganic pigment fine particles, and the range of mordant selection is expanded. can do.
[0026]
The colorant receiving layer coating solution can be prepared, for example, as follows.
That is, the specific surface area by the BET method is 200 m.²/ G or more fine particles of gas phase method silica are added to water (for example, 10 to 20% by mass), and using a high-speed rotating wet colloid mill (for example, Claremix (M Technique Co., Ltd.)), For example, after being dispersed for 20 minutes (preferably 10 to 30 minutes) under high-speed rotation conditions of 10,000 rpm (preferably 5000 to 20000 rpm), an aqueous polyvinyl alcohol solution (for example, PVA having a mass of about 1/3 of silica) ) And further dispersing under the same rotation conditions as described above. The obtained coating liquid is a uniform sol, and a porous colorant receiving layer having a three-dimensional network structure can be formed by coating and forming this on a support by the following coating method.
If necessary, a surfactant, a pH adjuster, an antistatic agent and the like can be added to the colorant-receiving layer coating solution.
[0027]
The colorant receiving layer coating solution can be applied by a known coating method such as an extrusion die coater, an air doctor coater, a bread coater, a rod coater, a knife coater, a squeeze coater, a reverse roll coater, or a bar coater.
[0028]
After the colorant-receiving layer coating solution is applied, a cross-linking agent solution is applied to the coating film. The cross-linking agent solution is in the middle of drying after the application, and before the reduced rate drying rate is exhibited. It is suitable to be applied to a coating film having a water content of 1000 to 200%. That is, after the colorant-receiving layer coating solution is applied, it is preferably produced by introducing a crosslinking agent and a mordant while the coating film exhibits a constant rate of drying. At this time, if the moisture content of the coating film is greater than the above range, gloss unevenness may occur or the surface may have a crusty skin shape. If the moisture content is less than the above range, cracks may occur in the coating film. Among these water content ranges (1000 to 200%), the case of 500 to 300% is more preferable.
[0029]
Here, “before the coating film shows a decreasing rate of drying” usually means several minutes immediately after the application of the colorant-receiving layer coating solution, and during this time, the solvent in the coated coating film The constant rate drying rate which is a phenomenon in which the content of is decreased in proportion to time. About the time which shows this constant rate drying rate, it describes in chemical engineering manual (p.707-712, Maruzen Co., Ltd. issue, October 25, 1980).
[0030]
The coating film is dried until it shows a reduced rate of drying as described above. At this time, the film surface wind speed is set to 10 m / sec or less, and the drying air temperature is set to a temperature exceeding 30 ° C. Then, the film surface temperature is set to a temperature exceeding 20 ° C. for drying. Details are as described above.
[0031]
As a method of giving before the coating film shows a decreasing rate of drying, (1) a method of further applying a crosslinking agent solution onto the coating film, (2) a method of spraying by a spraying method, 3) A method of immersing the support on which the coating film is formed in the crosslinking agent solution.
In the above method (1), as a coating method for applying the crosslinking agent solution, for example, curtain flow coater, extrusion die coater, air doctor coater, bread coater, rod coater, knife coater, squeeze coater, reverse roll coater, bar coater, etc. A known coating method can be used. However, it is preferable to use a method in which the coater does not come into direct contact with the already formed coating film, such as an extrusion die coater, curtain flow coater, bar coater or the like.
The amount of the crosslinking agent solution applied on the colorant receiving layer is 0.01 to 10 g / m in terms of crosslinking agent.²Is generally 0.05 to 5 g / m²Is preferred.
[0032]
In this invention, after providing the said crosslinking agent solution, it is preferable to dry the said coating film to which this solution was provided with the film surface temperature of 25-50 degreeC. Especially, 30-40 degreeC is especially preferable.
If the film surface temperature at the time of drying after application of the crosslinking agent solution is less than 25 ° C., the production efficiency may be lowered more than necessary, and if it exceeds 50 ° C., the coating film may be cracked. In addition, after a coating film dries, the surface temperature may exceed 50 degreeC.
[0033]
At this time, the dryer used for drying can be appropriately selected from a slit nozzle dryer, a floater dryer, and the like. In the case of the floater dryer, either a positive pressure type nozzle or a negative pressure type nozzle may be used. Specifically, it is as described above.
However, when a slit nozzle is used, the slit interval is preferably 200 mm or less, more preferably 50 to 200 mm, from the viewpoint of making the distribution of the heat transfer coefficient in the longitudinal direction of the coating film as uniform as possible and preventing uneven drying. preferable.
[0034]
The drying after the application of the crosslinking agent solution is performed in the range of the film surface temperature in the range of 25 to 50 ° C. as described above. At the same time, the film surface air speed of the drying air is set to 10 m / sec or more, and the drying air temperature is set to 40 ° C. It is preferable to set the temperature to exceed.
When the film surface wind speed is less than 10 m / sec, it may take a long time to complete drying, and among them, 10 to 20 m / sec is preferable.
When the drying air temperature is 40 ° C. or lower, drying may be poor, and among them, 60 to 120 ° C. is preferable.
[0035]
Further, after the coating film is dried, it may be further heated at a temperature of 40 to 180 ° C. to be dried and cured. Especially, it is preferable to heat at 40-150 degreeC for 1 to 20 minutes. For example, when borax or boric acid is used as the cross-linking agent in the cross-linking agent solution, heating at 60 to 100 ° C. is preferably performed for 5 to 20 minutes.
[0036]
After the colorant receiving layer is formed on the support, the colorant receiving layer is made of, for example, a super calender, a gloss calendar, etc., and subjected to a calendering process between the roll nips under heat and pressure, so that surface smoothness, gloss It is possible to improve the degree, transparency and coating strength. However, the calendar process may cause a decrease in the porosity (that is, the ink absorptivity may be decreased), so it is necessary to set the conditions under which the decrease in the porosity is small.
[0037]
As roll temperature in the case of performing a calendar process, 30-150 degreeC is preferable and 40-100 degreeC is more preferable.
Moreover, as a linear pressure between rolls at the time of a calendar process, 50-400 kg / cm is preferable and 100-200 kg / cm is more preferable.
[0038]
The layer thickness of the colorant receiving layer needs to be determined in relation to the void ratio in the layer because it needs to have an absorption capacity sufficient to absorb all droplets in the case of inkjet recording. For example, the ink amount is 8 nL / mm²In the case where the porosity is 60%, a film having a layer thickness of about 15 μm or more is required.
Considering this point, in the case of inkjet recording, the thickness of the colorant receiving layer is preferably 10 to 50 μm.
[0039]
The pore diameter of the colorant receiving layer is preferably 0.005 to 0.030 μm, more preferably 0.01 to 0.025 μm in terms of median diameter.
The porosity and pore median diameter can be measured using a mercury porosimeter (bore sizer 9320-PC2, manufactured by Shimadzu Corporation).
[0040]
The color material receiving layer is preferably excellent in transparency. As a guide, the haze value when the color material receiving layer is formed on a transparent film support is 30% or less. Preferably, it is 20% or less.
The haze value can be measured using a haze meter (HGM-2DP, manufactured by Suga Test Instruments Co., Ltd.).
[0041]
Since the coating film (preferably a coating film by the WOW method) to which the colorant-receiving layer coating solution has been applied as described above is dried, the surface is uniform and has a strong three-dimensional network without occurrence of cracks or uneven drying. A colorant receiving layer having a structure can be formed, and productivity (production efficiency) can be improved and production cost can be reduced. In addition, the formed colorant receiving layer has the above-described various properties such as ink absorptivity, color density, water resistance, and storage stability, and can form sharp and high-quality images without bleeding.
[0042]
-Support-
As the support, either a transparent support made of a transparent material such as plastic or an opaque support made of an opaque material such as paper can be used. In order to make use of the transparency of the colorant receiving layer, it is preferable to use a transparent support or a highly glossy opaque support.
[0043]
The material that can be used for the transparent support is preferably a material that is transparent and can withstand radiant heat when used in an OHP or a backlight display. Examples of the material include polyesters such as polyethylene terephthalate (PET); polysulfone, polyphenylene oxide, polyimide, polycarbonate, polyamide and the like. Of these, polyesters are preferable, and polyethylene terephthalate is particularly preferable.
Although there is no restriction | limiting in particular as thickness of the said transparent support body, 50-200 micrometers is preferable at the point of handleability.
[0044]
As the highly glossy opaque support, one having a glossiness of 40% or more on the surface on which the colorant receiving layer is provided is preferable. The glossiness is a value determined according to the method described in JIS P-8142 (75-degree specular gloss test method for paper and paperboard). Specifically, the following supports are mentioned.
[0045]
For example, high gloss paper support such as art paper, coated paper, cast coated paper, baryta paper used for silver salt photographic support, etc .; polyesters such as polyethylene terephthalate (PET), nitrocellulose, cellulose acetate , Cellulose esters such as cellulose acetate butyrate, and plastic films such as polysulfone, polyphenylene oxide, polyimide, polycarbonate, and polyamide are made opaque by adding a white pigment or the like (surface calendering may be applied). Glossy film; or a support in which a polyolefin coating layer containing or not containing a white pigment is provided on the surface of a highly glossy film containing the various paper supports, the transparent support or the white pigment. Is mentioned.
Furthermore, a white pigment-containing foamed polyester film (for example, foamed PET containing polyolefin fine particles and forming voids by stretching) can also be suitably exemplified.
[0046]
Although there is no restriction | limiting in particular also about the thickness of the said opaque support body, 50-300 micrometers is preferable at the point of handleability.
[0047]
The support may be subjected to corona discharge treatment, glow discharge treatment, flame treatment, ultraviolet irradiation treatment or the like.
[0048]
Next, the base paper used for the paper support will be described in detail.
As the base paper, wood pulp is used as a main raw material, and paper is made using synthetic pulp such as polypropylene or synthetic fibers such as nylon or polyester in addition to wood pulp as necessary. As the wood pulp, any of LBKP, LBSP, NBKP, NBSP, LDP, NDP, LUKP, and NUKP can be used, but it is preferable to use more LBKP, NBSP, LBSP, NDP, and LDP with a large amount of short fibers. preferable.
However, the ratio of LBSP and / or LDP is preferably 10% by mass or more and 70% by mass or less.
[0049]
The pulp is preferably a chemical pulp (sulfate pulp or sulfite pulp) with few impurities, and a pulp having a whiteness improved by bleaching is also useful.
[0050]
In the base paper, sizing agents such as higher fatty acids and alkyl ketene dimers, white pigments such as calcium carbonate, talc and titanium oxide, paper strength enhancing agents such as starch, polyacrylamide and polyvinyl alcohol, fluorescent whitening agents, polyethylene glycols A water retaining agent such as a dispersant, a softening agent such as a quaternary ammonium, and the like can be appropriately added.
[0051]
The freeness of the pulp used for papermaking is preferably 200 to 500 ml as defined by CSF, and the fiber length after beating is a 24 mesh residual mass% defined by JIS P-8207 and a 42 mesh fraction. 30 to 70% of the sum with the mass% of is preferable. In addition, it is preferable that the mass% of 4 mesh remainder is 20 mass% or less.
[0052]
The basis weight of the base paper is preferably 30 to 250 g, and particularly preferably 50 to 200 g. The thickness of the base paper is preferably 40 to 250 μm. The base paper can be given a high smoothness by calendering at the paper making stage or after paper making. Base paper density is 0.7-1.2g / m²(JIS P-8118) is common.
Furthermore, the base paper stiffness is preferably 20 to 200 g under the conditions specified in JIS P-8143.
[0053]
A surface sizing agent may be applied to the surface of the base paper. As the surface sizing agent, a sizing agent similar to the size that can be added to the base paper can be used.
The pH of the base paper is preferably 5 to 9 when measured by a hot water extraction method defined in JIS P-8113.
[0054]
The polyethylene covering the front and back surfaces of the base paper is mainly low-density polyethylene (LDPE) and / or high-density polyethylene (HDPE), but some other LLDPE, polypropylene, etc. can also be used.
[0055]
In particular, the polyethylene layer on the side on which the colorant-receiving layer is formed has improved opacity and whiteness by adding rutile or anatase type titanium oxide into polyethylene, as is widely done in photographic paper. Those are preferred. Here, as a titanium oxide content, about 3-20 mass% is preferable with respect to polyethylene, and 4-13 mass% is more preferable.
[0056]
Polyethylene-coated paper can be used as glossy paper, or matte or silky surface that can be obtained with ordinary photographic printing paper by applying a so-called molding process when polyethylene is melt-extruded and coated on the base paper surface. Can also be used.
[0057]
[Structural component]
Next, each component which comprises a color material receiving layer coating liquid and a crosslinking agent solution is explained in full detail.
-Inorganic pigment fine particles-
The color material receiving layer coating liquid according to the present invention contains inorganic pigment fine particles, and the color material receiving layer is formed into a porous structure containing inorganic pigment fine particles by coating the coating liquid on a support. A layer can be formed.
[0058]
Examples of the inorganic pigment fine particles include silica fine particles, colloidal silica, titanium dioxide, barium sulfate, calcium silicate, zeolite, kaolinite, halloysite, mica, talc, calcium carbonate, magnesium carbonate, calcium sulfate, boehmite, pseudoboehmite and the like. Can be mentioned.
[0059]
Since the silica fine particles have a particularly large specific surface area, the ink absorbency and retention efficiency are high, and the refractive index is low. Therefore, if the dispersion is made to an appropriate particle size, transparency can be imparted to the receiving layer and high color density can be obtained. And good color developability is preferred. The transparent colorant-receiving layer provides high color density and good color development gloss not only for applications that require transparency, such as OHP, but also when used for recording sheets such as photo glossy paper. Important in terms.
[0060]
The silica fine particles are roughly classified into wet method particles and dry method particles according to the production method.
In the wet method, a method is mainly used in which active silica is produced by acid decomposition of silicate, and this is appropriately polymerized and coagulated and precipitated to obtain hydrous silica. On the other hand, the dry method (gas phase method) is a method using high-temperature gas phase hydrolysis of silicon halide (flame hydrolysis method), and silica sand and coke are heated and reduced by an arc in an electric furnace by means of an arc. The method of obtaining anhydrous silica by the oxidation method (arc method) is the mainstream.
The hydrous silica and anhydrous silica obtained by these methods are different in the density of silanol groups on the surface, the presence or absence of vacancies, etc., and show different properties, respectively, especially in the case of anhydrous silica (anhydrous silicic acid). It is particularly preferable because a three-dimensional structure having a high porosity is easily formed. The reason for this is not clear, but in the case of hydrous silica, the density of silanol groups on the surface of the fine particles is 5 to 8 / nm.²In the case of anhydrous silica, the density of silanol groups on the surface of the fine particles is 2 to 3 / nm.²Therefore, it is presumed that the structure becomes sparsely soft agglomerated (flocculated), and as a result, has a structure with a high porosity.
Therefore, in the present invention, silica fine particles obtained by the gas phase method (the density of silanol groups on the surface of the fine particles is 2 to 3 / nm).²It is preferable to use (silica).
[0061]
Therefore, when the silica fine particles are used, the particles are likely to adhere to each other due to hydrogen bonding due to silanol groups on the surface thereof, so that a porous structure having a large porosity can be formed particularly when the average primary particle diameter is 30 nm or less. Ink absorption characteristics can be effectively improved.
[0062]
Furthermore, the specific surface area according to the BET method is 200 m from the point that it is easy to make a porous material and can form a colorant receiving layer excellent in ink absorbability.²/ G or more of vapor phase silica (hereinafter sometimes simply referred to as “vapor phase silica”) is preferred.
The BET method refers to a method for measuring the average diameter of primary particles described in items 2 and 2 of “Technical Document No. 10 of Nippon Aerosil Co., Ltd.”. As the vapor phase silica in the present invention, the specific surface area calculated using the BET method is 200 m.²/ G or more is preferable, 220 m²/ G or more is more preferable, and further 300 m²/ G or more is particularly preferable.
In addition, as an average primary particle diameter of the said inorganic pigment fine particle, 30 nm or less is preferable, 10 nm or less is preferable and 3-10 nm is more preferable.
[0063]
From the viewpoint of transparency, the type of resin to be combined with the silica fine particles is important. When anhydrous silica is used, the water-soluble resin is preferably polyvinyl alcohol (PVA), and particularly, a saponification degree of 70 to 99%. PVA is more preferable, and PVA having a saponification degree of 70 to 90% is most preferable.
[0064]
The PVA has a hydroxyl group in its structural unit, and this hydroxyl group and a silanol group on the surface of the silica fine particle form a hydrogen bond, thereby making it easy to form a three-dimensional network structure in which the secondary particle of the silica fine particle is a chain unit. . By forming the three-dimensional network structure, it is considered that a color material receiving layer having a porous structure with a high porosity can be formed.
The porous colorant-receiving layer thus obtained can rapidly absorb ink by capillary action in ink jet recording and form dots with good roundness without ink bleeding.
[0065]
The content ratio of the inorganic pigment fine particles (preferably silica fine particles; i) to the water-soluble resin (p) [PB ratio (i: p), the mass of the inorganic pigment fine particles relative to 1 part by mass of the water-soluble resin] The film structure is greatly affected. That is, as the PB ratio increases, the porosity, pore volume, and surface area (per unit mass) increase.
Specifically, the PB ratio (i: p) is preferably 1.5: 1 to 10: 1. When the PB ratio exceeds 10: 1, that is, when the PB ratio is too large, the film strength may be reduced, and cracking may occur during drying. The ratio is less than 1.5: 1, that is, the PB ratio is too small. As a result, the voids are likely to be blocked by the resin, and as a result, the void ratio may decrease and the ink absorbability may decrease.
[0066]
Since stress may be applied to the recording sheet when passing through the conveyance system of the ink jet printer, the colorant receiving layer needs to have sufficient film strength. Further, when cutting into a sheet shape, it is necessary that the color material receiving layer has sufficient film strength in order to prevent the color material receiving layer from being cracked or peeled off.
In this case, the PB ratio is preferably 5: 1 or less, and preferably 2: 1 or more from the viewpoint of securing high-speed ink absorbability with an inkjet printer.
For example, a coating liquid in which anhydrous silica fine particles having an average primary particle size of 30 nm or less and a water-soluble resin are completely dispersed in an aqueous solution at a PB ratio of 2: 1 to 5: 1 is applied onto a support, When dried, a three-dimensional network structure is formed with the secondary particles of silica fine particles as chain units, the average pore diameter is 30 nm or less, the porosity is 50% or more, the pore specific volume is 0.5 ml / g or more, the specific surface area Is 100m²A translucent porous film of at least / g can be easily formed.
[0067]
-Water-soluble resin-
Examples of the water-soluble resin include a resin having a hydroxyl group as a hydrophilic structural unit, such as polyvinyl alcohol (PVA), cation-modified polyvinyl alcohol, anion-modified polyvinyl alcohol, silanol-modified polyvinyl alcohol, polyvinyl acetal, and cellulose resin [ Methyl cellulose (MC), ethyl cellulose (EC), hydroxyethyl cellulose (HEC), carboxymethyl cellulose (CMC), etc.], chitins, chitosans, starch; polyethylene oxide (PEO) and polypropylene oxide (PPO) which are resins having an ether bond , Polyethylene glycol (PEG), polyvinyl ether (PVE); polyacrylamide (PAAM) which is a resin having an amide group or an amide bond, poly Nirupiroridon (PVP) and the like.
In addition, polyacrylates, maleic resins, alginates, and gelatins having a carboxyl group as a dissociable group can be exemplified.
Among the above, polyvinyl alcohols are particularly preferable.
[0068]
The polymerization degree of the water-soluble resin is preferably 1800 or more, and more preferably 2000 to 4000.
When the degree of polymerization is less than 1800, the viscosity of the colorant-receiving layer coating solution becomes too low and it becomes difficult to make it porous.
[0069]
As content of the said water-soluble resin, 9-40 mass% is preferable with respect to the total solid content mass of a color material receiving layer, and 16-33 mass% is more preferable.
When the content is less than 9% by mass, the film strength is lowered, and cracking is likely to occur during drying. When the content exceeds 40% by mass, the voids are easily blocked by the resin. May decrease and the ink absorbency may decrease.
[0070]
The inorganic pigment fine particles and the water-soluble resin, which mainly constitute the color material receiving layer, may be a single material or a mixed system of a plurality of materials.
[0071]
-Crosslinking agent-
In the colorant receiving layer of the ink jet recording sheet of the present invention, a coating solution (porous layer) containing inorganic pigment fine particles and a water-soluble resin is further provided with a solution containing a crosslinking agent and preferably a mordant (crosslinking agent solution). The water-soluble resin is preferably cured by a crosslinking reaction with the crosslinking agent.
[0072]
The application of the crosslinking agent solution is performed before the coating film formed by applying the coating liquid for forming the porous color material receiving layer (color material receiving layer coating liquid) exhibits a reduced rate of drying. To be done. By this operation, it is possible to effectively prevent the generation of cracks that occur during the drying of the coating film. That is, the cross-linking agent solution penetrates into the coating film at the same time as the coating solution is applied or before the coating film shows a reduced rate of drying, and reacts quickly with the water-soluble resin in the coating film, By gelling (curing) the water-soluble resin, the film strength of the coating film is immediately and greatly improved.
[0073]
As the cross-linking agent capable of cross-linking the water-soluble resin, a suitable material may be selected as appropriate in relation to the water-soluble resin used in the colorant receiving layer. Among these, boron is used because of its rapid cross-linking reaction. Compounds are preferred, such as borax, boric acid, borates (eg orthoborate, InBO_Three, ScBO_Three, YBO_Three, LaBO_Three, Mg_Three(BO_Three)₂  , Co_Three(BO_Three)₂Diborate (eg Mg₂B₂O_Five, Co₂B₂O_Five), Metaborates (eg LiBO)₂, Ca (BO₂)₂, NaBO₂, KBO₂), Tetraborate (eg, Na₂B_FourO₇・ 10H₂O), pentaborate (for example, KB)_FiveO₈・ 4H₂O, Ca₂B₆O₁₁・ 7H₂O, CsB_FiveO_Five), Glyoxal, melamine / formaldehyde (for example, methylolmelamine, alkylated methylolmelamine), methylolurea, resol resin, polyisocyanate, epoxy resin and the like.
Among these, borax, boric acid and borates are preferable, borates are more preferable, and a water-soluble resin is particularly preferably used in combination with polyvinyl alcohol in that a rapid crosslinking reaction is caused.
[0074]
When gelatin is used as the water-soluble resin, the following compounds known as gelatin hardeners can be used as a crosslinking agent. For example, aldehyde compounds such as formaldehyde, glyoxal and glutaraldehyde; ketone compounds such as diacetyl and cyclopentanedione; bis (2-chloroethylurea) -2-hydroxy-4,6-dichloro-1,3,5- Active halogen compounds such as triazine and 2,4-dichloro-6-S-triazine sodium salt; divinylsulfonic acid, 1,3-vinylsulfonyl-2-propanol, N, N′-ethylenebis (vinylsulfonylacetamide) ), Active vinyl compounds such as 1,3,5-triacryloyl-hexahydro-S-triazine; N-methylol compounds such as dimethylolurea and methyloldimethylhydantoin;
[0075]
Isocyanate compounds such as 1,6-hexamethylene diisocyanate; aziridine compounds described in US Pat. Nos. 3,017,280 and 2,983611; carboximide compounds described in US Pat. No. 3,100,704; glycerol triglycidyl Epoxy compounds such as ether; Ethyleneimino compounds such as 1,6-hexamethylene-N, N′-bisethyleneurea; Halogenated carboxaldehyde compounds such as mucochloric acid and mucophenoxycyclolic acid; 2,3-dihydroxy Dioxane compounds such as dioxane; chromium alum, potash alum, zirconium sulfate, chromium acetate and the like.
In addition, the said crosslinking agent may be single 1 type, or may combine 2 or more types.
[0076]
The crosslinking agent solution is prepared by dissolving the crosslinking agent in water and / or an organic solvent.
As a density | concentration of the crosslinking agent in a crosslinking agent solution, 0.05-10 mass% is preferable with respect to the mass of a crosslinking agent solution, and 0.1-7 mass% is especially preferable.
As a solvent constituting the crosslinking agent solution, water is generally used, and an aqueous mixed solvent containing an organic solvent miscible with water may be used.
The organic solvent can be arbitrarily used as long as it can dissolve the cross-linking agent. For example, alcohols such as methanol, ethanol, isopropyl alcohol, and glycerin; ketones such as acetone and methyl ethyl ketone; methyl acetate, ethyl acetate, and the like An aromatic solvent such as toluene; an ether such as tetrahydrofuran; and a halogenated carbon-based solvent such as dichloromethane.
[0077]
-Mordant-
In the present invention, a mordant is contained in the colorant receiving layer from the viewpoint of preventing ink bleeding of the formed image, further improving water resistance and aging resistance.
The mordant is a cationic polymer (cationic mordant), and when present in the colorant receiving layer, it interacts with the liquid ink having an anionic dye as a colorant to stabilize the colorant. Water resistance and aging blur can be improved.
[0078]
However, if this is added directly to the coating solution for forming the colorant-receiving layer, there is a possibility of causing agglomeration with inorganic pigment fine particles having an anionic charge such as silica. If a method of preparing and applying as a solution is used, there is no need to worry about aggregation of inorganic pigment fine particles. Therefore, in the present invention, it is preferable to use it in a crosslinking agent solution.
[0079]
As the cationic mordant, a polymer mordant having a primary to tertiary amino group or a quaternary ammonium base as a cationic group is preferably used, but a cationic non-polymer mordant may also be used. it can.
Examples of the polymer mordant include a homopolymer of a monomer having a primary to tertiary amino group and a salt thereof, or a quaternary ammonium base (mordant monomer), and the mordant monomer and other monomers (hereinafter, What is obtained as a copolymer or condensation polymer with "non-mordant polymer") is preferred. These polymer mordants can be used in any form of a water-soluble polymer or water-dispersible latex particles.
[0080]
Examples of the monomer (mordanting monomer) include trimethyl-p-vinylbenzylammonium chloride, trimethyl-m-vinylbenzylammonium chloride, triethyl-p-vinylbenzylammonium chloride, triethyl-m-vinylbenzylammonium chloride, N , N-dimethyl-N-ethyl-Np-vinylbenzylammonium chloride, N, N-diethyl-N-methyl-Np-vinylbenzylammonium chloride, N, N-dimethyl-Nn-propyl-N -P-vinylbenzylammonium chloride, N, N-dimethyl-Nn-octyl-Np-vinylbenzylammonium chloride, N, N-dimethyl-N-benzyl-Np-vinylbenzylammonium chloride, N, N-die Ru-N-benzyl-Np-vinylbenzylammonium chloride, N, N-dimethyl-N- (4-methyl) benzyl-Np-vinylbenzylammonium chloride, N, N-dimethyl-N-phenyl-N -P-vinylbenzylammonium chloride,
[0081]
Trimethyl-p-vinylbenzylammonium bromide, trimethyl-m-vinylbenzylammonium bromide, trimethyl-p-vinylbenzylammonium sulfonate, trimethyl-m-vinylbenzylammonium sulfonate, trimethyl-p-vinylbenzylammonium acetate, trimethyl-m-vinyl Benzylammonium acetate, N, N, N-triethyl-N-2- (4-vinylphenyl) ethylammonium chloride, N, N, N-triethyl-N-2- (3-vinylphenyl) ethylammonium chloride, N, N-diethyl-N-methyl-N-2- (4-vinylphenyl) ethylammonium chloride, N, N-diethyl-N-methyl-N-2- (4-vinylphenyl) ethylammonium chloride Tate,
[0082]
N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, N, N-diethylaminopropyl (meth) acrylate, N, N- Methyl chloride, ethyl chloride, methyl bromide of dimethylaminoethyl (meth) acrylamide, N, N-diethylaminoethyl (meth) acrylamide, N, N-dimethylaminopropyl (meth) acrylamide, N, N-diethylaminopropyl (meth) acrylamide , Quaternized products of ethyl bromide, methyl iodide or ethyl iodide, or sulfonates, alkyl sulfonates, acetates or alkyl carboxylates substituted with their anions.
[0083]
Specifically, for example, trimethyl-2- (methacryloyloxy) ethylammonium chloride, triethyl-2- (methacryloyloxy) ethylammonium chloride, trimethyl-2- (acryloyloxy) ethylammonium chloride, triethyl-2- (acryloyloxy) ) Ethylammonium chloride, trimethyl-3- (methacryloyloxy) propylammonium chloride, triethyl-3- (methacryloyloxy) propylammonium chloride, trimethyl-2- (methacryloylamino) ethylammonium chloride, triethyl-2- (methacryloylamino) ethyl Ammonium chloride, trimethyl-2- (acryloylamino) ethylammonium chloride, triethyl-2- ( Acryloylamino) ethylammonium chloride, trimethyl-3- (methacryloylamino) propylammonium chloride, triethyl-3- (methacryloylamino) propylammonium chloride, trimethyl-3- (acryloylamino) propylammonium chloride, triethyl-3- (acryloyl) Amino) propylammonium chloride,
[0084]
N, N-dimethyl-N-ethyl-2- (methacryloyloxy) ethylammonium chloride, N, N-diethyl-N-methyl-2- (methacryloyloxy) ethylammonium chloride, N, N-dimethyl-N-ethyl- 3- (acryloylamino) propylammonium chloride, trimethyl-2- (methacryloyloxy) ethylammonium bromide, trimethyl-3- (acryloylamino) propylammonium bromide, trimethyl-2- (methacryloyloxy) ethylammonium sulfonate, trimethyl-3- And (acryloylamino) propylammonium acetate.
In addition, examples of copolymerizable monomers include N-vinylimidazole and N-vinyl-2-methylimidazole.
[0085]
The non-mordant polymer does not contain a basic or cationic moiety such as a primary to tertiary amino group and a salt thereof, or a quaternary ammonium base, and does not show an interaction with a dye in an inkjet ink. Or the monomer which interaction is substantially small is said.
Examples of the non-mordant monomer include (meth) acrylic acid alkyl ester; (meth) acrylic acid cycloalkyl ester such as cyclohexyl (meth) acrylate; (meth) acrylic acid aryl ester such as phenyl (meth) acrylate; Aralkyl esters such as (meth) benzyl acrylate; Aromatic vinyls such as styrene, vinyl toluene and α-methylstyrene; Vinyl esters such as vinyl acetate, vinyl propionate and vinyl versatic acid; Allyl esters such as allyl acetate Halogen-containing monomers such as vinylidene chloride and vinyl chloride; vinyl cyanide such as (meth) acrylonitrile; olefins such as ethylene and propylene; and the like.
[0086]
The (meth) acrylic acid alkyl ester is preferably a (meth) acrylic acid alkyl ester having 1 to 18 carbon atoms in the alkyl moiety, such as methyl (meth) acrylate, ethyl (meth) acrylate, (meth) Propyl acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, hexyl (meth) acrylate, octyl (meth) acrylate, Examples include 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, and the like. Of these, methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, and hydroxyethyl methacrylate are preferable.
The non-mordant monomers can also be used singly or in combination of two or more.
[0087]
Further, as a polymer mordant, polydiallyldimethylammonium chloride, polymethacryloyloxyethyl-β-hydroxyethyldimethylammonium chloride, polyethyleneimine, polyallylamine, polyallylamine hydrochloride, polyamide-polyamine resin, cationized starch, dicyandiamide formalin condensate Dimethyl-2-hydroxypropylammonium salt polymer, polyamidine, polyvinylamine and the like can also be mentioned as preferable examples.
[0088]
The molecular weight of the polymer mordant is preferably 1000 to 200000, more preferably 3000 to 40000.
When the molecular weight is less than 1000, the water resistance tends to be insufficient, and when it exceeds 200,000, the viscosity becomes too high and handling suitability may be lowered.
[0089]
As the cationic non-polymer mordant, for example, water-soluble metal salts such as aluminum sulfate, aluminum chloride, polyaluminum chloride, and magnesium chloride are preferable.
[0090]
Among these, polyallylamine having a molecular weight of 3000 to 40000 is particularly preferable from the viewpoints of excellent ink retention, high-resolution images without aging blur, and long-term retention.
[0091]
-Other ingredients-
The color material receiving layer may contain the following components as needed.
Various ultraviolet absorbers, antioxidants, singlet oxygen quenchers and the like may be included for the purpose of suppressing deterioration of the color material.
Examples of the ultraviolet absorber include cinnamic acid derivatives, benzophenone derivatives, benzotriazolylphenol derivatives, and the like. For example, α-cyano-phenyl cinnamate butyl, o-benzotriazole phenol, o-benzotriazole-p-chlorophenol, o-benzotriazole-2,4-di-t-butylphenol, o-benzotriazole-2,4 -Di-t-octylphenol etc. are mentioned. A hindered phenol compound can also be used as an ultraviolet absorber, and specifically, a phenol derivative in which at least one of 2-position or 6-position is substituted with a branched alkyl group is preferable.
[0092]
Moreover, a benzotriazole type ultraviolet absorber, a salicylic acid type ultraviolet absorber, a cyanoacrylate type ultraviolet absorber, an oxalic acid anilide type ultraviolet absorber, etc. can be used. For example, JP-A 47-10537, 58-111942, 58-21284, 59-19945, 59-46646, 59-109055, 63-53544, and JP-B 36-36. 10466, 42-26187, 48-30492, 48-31255, 48-41572, 48-54965, 50-10726, U.S. Pat.No. 2,719,086, 3,707,375, 3,754,919, 4,220,711 and the like.
[0093]
A fluorescent brightening agent can also be used as an ultraviolet absorber, and examples thereof include a coumarin fluorescent brightening agent. Specific examples are described in JP-B Nos. 45-4699 and 54-5324.
[0094]
Examples of the antioxidant include European Patent Publication No. 223739, Publication No. 309401, Publication No. 309402, Publication No. 310551, Publication No. 310552, Publication No. 4594416, Publication of German Patent No. 3435443, JP-A-54-48535, JP-A-60-107384, JP-A-60-107383, JP-A-60-125470, JP-A-60-125471, JP-A-60-125472, JP-A-60-287485. 60-287486, 60-287487, 60-287488, 61-160287, 61-185483, 61-2111079, 62-146678, 62-146680, 62-146679, 62-282885, JP same 62-262047, JP-same 63-051174, JP-same 63-89877, JP-same 63-88380, JP-same 66-88381, JP-same 63-113536, JP-
[0095]
JP-A-63-163351, JP-A-63-203372, JP-A-63-224989, JP-A-63-251282, JP-A-63-267594, JP-A-63-182484, JP-A-1-239282, JP-A-2-262654, JP-A-2-71262, JP-A-3-121449, JP-A-4-29185, JP-A-4-291684, JP-A-5-61166, JP-A-5-119449, 5-188687, 5-188686, 5-110490, 5-110437, 5-170361, JP 48-43295, 48-33212, Examples thereof include those described in U.S. Pat. Nos. 4,814,262 and 4,980,275.
[0096]
Specifically, 6-ethoxy-1-phenyl-2,2,4-trimethyl-1,2-dihydroquinoline, 6-ethoxy-1-octyl-2,2,4-trimethyl-1,2-dihydroquinoline 6-ethoxy-1-phenyl-2,2,4-trimethyl-1,2,3,4-tetrahydroquinoline, 6-ethoxy-1-octyl-2,2,4-trimethyl-1,2,3 4, -tetrahydroquinoline, nickel cyclohexane acid, 2,2-bis (4-hydroxyphenyl) propane, 1,1-bis (4-hydroxyphenyl) -2-ethylhexane, 2-methyl-4-methoxy-diphenylamine, Examples include 1-methyl-2-phenylindole.
[0097]
The light resistance improvers may be used alone or in combination of two or more. This light resistance improver may be water-solubilized, dispersed, emulsified, or included in microcapsules.
The addition amount of the light fastness improver is preferably 0.01 to 10% by mass of the colorant receiving layer coating solution.
[0098]
In addition, for the purpose of improving the dispersibility of the inorganic pigment fine particles, various inorganic salts, pH adjusting agents, and the like may contain acids and alkalis.
In addition, various surfactants are used for the purpose of improving coating suitability and surface quality, and surfactants having ionic conductivity and metal oxide fine particles having electronic conductivity are used for the purpose of suppressing surface frictional charge and peeling charge. Various matting agents may be included for the purpose of reducing the frictional properties of the surface.
[0099]
【Example】
EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these Examples. In the examples, “parts” and “%” all represent “parts by mass” and “% by mass”.
[0100]
-Production of support-
Wood pulp composed of 100 parts of LBKP is beaten to 300 ml Canadian freeness with a double disc refiner, 0.5 parts of epoxidized behenamide, 1.0 part of anionic polyacrylamide, 0.1 part of polyamide polyamine epichlorohydrin, 0.5 part of cationic polyacrylamide All parts were added at an absolute dry weight ratio to the pulp, and weighed by a long paper machine to be 170 g / m.²Paper was made.
[0101]
In order to adjust the surface size of the base paper, 0.04% of a fluorescent whitening agent (Whitetex BB, manufactured by Sumitomo Chemical Co., Ltd.) is added to a 4% aqueous solution of polyvinyl alcohol, and this is 0.5 g in terms of absolute dry weight. / M²The base paper was impregnated so as to become, dried, and then subjected to calendar treatment to obtain a base paper adjusted to a density of 1.05.
[0102]
After the corona discharge treatment was performed on the wire surface (back surface) side of the obtained base paper, high-density polyethylene was coated to a thickness of 19 μm using a melt extruder to form a resin layer composed of a mat surface. (Hereinafter, the resin layer surface is referred to as “back surface”). The resin layer on the back side is further subjected to corona discharge treatment, and then, as an antistatic agent, aluminum oxide (alumina sol 100, manufactured by Nissan Chemical Industries, Ltd.) and silicon dioxide (Snowtex O, manufactured by Nissan Chemical Industries, Ltd.) ) And water in a 1: 2 ratio (mass ratio) with a dry weight of 0.2 g / m²It applied so that it might become.
[0103]
Furthermore, after the corona discharge treatment is applied to the felt surface (surface) side where the resin layer is not provided, anatase-type titanium dioxide 10%, a trace amount of ultramarine blue, and a fluorescent whitening agent 0.01% (vs. polyethylene) Low-density polyethylene containing MFR (melt flow rate) 3.8 is melt-extruded to a thickness of 29 μm using a melt extruder, and a high-gloss thermoplastic resin layer is formed on the surface side of the base paper. (Hereinafter, this highly glossy surface is referred to as a “front side”), which is used as a support.
[0104]
Example 1
-Preparation of coating solution for colorant receiving layer-
(1) Gas phase method silica fine particles and (2) ion-exchanged water in the following composition are mixed, and using a high-speed rotating colloid mill (CLEAMIX, manufactured by M Technique Co., Ltd.) for 20 minutes at a rotational speed of 10,000 rpm. After the dispersion, the following (3) polyoxyethylene lauryl ether, (4) aqueous ammonia, (5) 9% polyvinyl alcohol aqueous solution, and (6) diethylene glycol monobutyl ether were added, and further dispersed under the same conditions as above. A colorant receiving layer coating solution A was prepared.
The mass ratio of the silica fine particles to the water-soluble resin (PB ratio / (1) :( 5)) is 3.5: 1, and the pH of the colorant-receiving layer coating solution A is 9.5 (alkaline )Met.
[0105]
[Composition of Color Material Receiving Layer Coating Liquid A]
(1) Vapor phase silica fine particles (inorganic pigment fine particles) 9.9 parts
(Average primary particle diameter: 7 nm; Aerosil 300, manufactured by Nippon Aerosil Co., Ltd.)
(2) Ion exchange water: 72.6 parts
(3) Polyoxyethylene lauryl ether (surfactant) 7.2 parts
(Emulgen 109P (10%), manufactured by Kao Corporation, HLB value 13.6)
(4) 17 g / l ammonia aqueous solution (pH adjusting agent) 5.3 parts
(5) Polyvinyl alcohol 9% aqueous solution (water-soluble resin) 31.4 parts
(PVA-420, manufactured by Kuraray Co., Ltd., saponification degree 81.8%, polymerization degree 2000)
(6) Diethylene glycol monobutyl ether: 0.6 parts
[0106]
-Preparation of inkjet recording sheet-
After the corona discharge treatment is applied to the front surface of the support, the coating material A (solid content concentration 10%) obtained above is applied to the front surface by a slide bead coating method at a coating amount of 200 ml / m.²It applied so that it might become (application process). Thereafter, as shown in FIG. 1, the support after the application is provided with a nozzle interval (interval B in FIG. 1) of 200 mm on the side where the support is applied (that is, the membrane surface 2 side), the nozzle tip and the membrane surface 2 A plurality of slit nozzles 1 are arranged at a distance A of 50 mm (first half) / 10 mm (second half), and the drying in Table 1 below is performed in a drying zone in which rollers 3 are appropriately disposed on the side of the support that does not have a coating film. The condition A (front / second half 30 seconds each) was passed through and dried so that the moisture content of the coated film formed was 500%. During this period, the coating film showed a constant rate of drying (constant rate drying step).
Thereafter, a crosslinking agent solution A having the following composition was applied at a coating amount of 20 g / m using a knife coater.²It was applied to the surface of the coating film so as to be, and further dried with hot air at 80 ° C. for 40 seconds (drying step).
From the above, an inkjet recording sheet (1) of the present invention provided with a colorant receiving layer having a dry film thickness of 20 μm was obtained.
[0107]
[Composition of cross-linking agent solution A]
・ Boric acid (6%; crosslinking agent): 25 parts
PAS-F5000 (20%) aqueous solution 7.15 parts
(Mordant; Nittobo Co., Ltd.)
・ Ion exchange water: 68.98 parts
・ Ammonium chloride (surface pH adjuster): 0.2 parts
Aqueous ammonia solution (25%; pH adjuster) ... 1.67 parts
・ Polyoxyethylene lauryl ether (surfactant) 2 parts
(Emulgen 109P (10%), manufactured by Kao Corporation, HLB value 13.6)
[0108]
(Example 24)
  In Example 1, the present invention was carried out in the same manner as in Example 1 except that the drying conditions A in the drying before the application of the crosslinking agent solution A were changed to the drying conditions B to F in Table 1, respectively. Inkjet recording sheet (3) ~ (5) In addition, Example 35Then, it replaced with the drying zone provided with a slit nozzle, and set it as the drying zone provided with the negative pressure type nozzle floater comprised similarly to FIG.
[0109]
(Comparative Examples 1-6)
In Example 1, after the coating step, the drying condition A in the drying before the application of the crosslinking agent solution A was changed to the drying conditions G to L in Table 1, respectively. Inkjet recording sheets (7) to (12) were obtained. In Comparative Examples 3 to 6, a drying zone including a negative pressure type nozzle floater configured in the same manner as in FIG. 2 was used instead of the drying zone including the slit nozzle.
[0110]
(Evaluation)
  Inkjet recording sheet of the present invention obtained from the above (1)And (3) to (5)The following evaluation was performed for each of the inkjet recording sheets (7) to (12). The evaluation results are shown in Table 1 below.
-1. Cracks
  The surface state of the colorant receiving layer of each ink jet recording sheet was visually observed, and the presence or absence of cracks on the surface and the size thereof were evaluated according to the following criteria.
    [Standard]
    AA: No cracks were observed and it was good.
    BB: Cracks of about 1 to 2 mm in length were observed.
    CC: Cracks having a length of 3 mm or more were remarkably observed.
[0111]
-▲ 2 ▼ Glossiness (dry unevenness)-
The surface state of the colorant receiving layer of each ink jet recording sheet was visually observed, and the presence or absence of gloss unevenness on the surface was evaluated according to the following criteria.
[Standard]
○: Gloss unevenness was not recognized at all and was good.
Δ: Slight uneven gloss was observed at the edge of the colorant receiving layer.
X: Gloss unevenness was remarkably recognized.
[0112]
[Table 1]

[0113]
  From the results of Table 1 above, in Examples 1 to 6, in which the coating film having a moisture content of 500% was dried under the conditions that the film surface wind speed, the drying air temperature, and the film surface temperature of the drying air were defined in the present invention, Inkjet recording sheet that can be produced and is obtained (1)And (3) to (5)In addition, the colorant receiving layer was not accompanied by cracks or uneven glossiness. That is, productivity could be improved, and an inexpensive and good quality inkjet recording sheet could be manufactured. Further, when a negative pressure type nozzle is used (Examples 3 to 3)5) Was better in terms of drying unevenness.
  On the other hand, in the ink jet recording sheets (7) to (12) obtained without using the drying conditions defined in the present invention, cracks and gloss unevenness occurred, and improvement in productivity could not be achieved.
[0114]
(Reference Examples 1-6)
-Preparation of coating material B for colorant receiving layer-
The following (1) to (3) in the following composition were mixed and dispersed at a rotational speed of 10,000 rpm for 20 minutes using a high-speed rotating colloid mill (CLEAMIX, manufactured by M Technique Co., Ltd.), then the following ( A solution containing 4) to (8) was added, and further redispersed for 20 minutes at a rotational speed of 10000 rpm to prepare a colorant receiving layer coating solution B.
The mass ratio of the silica fine particles to the water-soluble resin (PB ratio / (1) :( 4)) was 4.5: 1, and the pH of the colorant-receiving layer coating solution B was 3.5 (acidic). It was.
[0115]
[Composition of Color Material Receiving Layer Coating Liquid B]
(1) Gas phase method silica fine particles (inorganic pigment fine particles) 10.0 parts
(Average primary particle size: 7 nm; Leorosil QS30, manufactured by Tokuyama Corporation)
(2) Ion exchange water: 51.7 parts
(3) PAS-M-1 (dispersing agent; manufactured by Nittobo Co., Ltd.) 0.83 parts
(4) Polyvinyl alcohol 8% aqueous solution (water-soluble resin) 27.8 parts
(PVA124, manufactured by Kuraray Co., Ltd., saponification degree 98.5%, polymerization degree 2400)
(5) Diethylene glycol monobutyl ether: 0.72 parts
(6) Polyoxyethylene lauryl ether (surfactant) 1.2 parts
(Emulgen 109P (10%), manufactured by Kao Corporation, HLB value 13.6)
(7) Ion exchange water: 30.74 parts
(8) Boric acid: 0.09 part
[0116]
-Preparation of inkjet recording sheet-
After the corona discharge treatment is performed on the front surface of the prepared support, the colorant receiving layer coating solution B (solid content 10%) obtained above is applied to the front surface by a slide bead coating method with a coating amount of 200 ml. / M²Then, the coating film was dried with hot air at 60 ° C. (wind speed 3 to 8 m / sec) with a hot air dryer until the moisture content of the coated film was 500%. During this period, the coating film showed a constant rate of drying (constant rate drying step).
Thereafter, a crosslinking agent solution B having the following composition was applied at a coating amount of 20 g / m using a knife coater.²Then, the coating was applied to the surface of the coating film and further dried with hot air at 40 to 140 ° C. for 40 seconds according to the drying conditions shown in Table 2 below (drying step).
From the above, inkjet recording sheets (a) to (f) provided with a colorant receiving layer having a dry film thickness of 20 μm were obtained.
[0117]
[Composition of cross-linking agent solution B]
・ Boric acid (6%; crosslinking agent): 25 parts
PAA-10C (10%) aqueous solution: 20 parts
(Mordant; Nittobo Co., Ltd.)
・ Ion-exchanged water: 52.8 parts
・ Ammonium chloride (surface pH adjuster): 0.2 parts
・ Polyoxyethylene lauryl ether (surfactant) 2 parts
(Emulgen 109P (10%), manufactured by Kao Corporation, HLB value 13.6)
[0118]
Each of the inkjet recording sheets (a) to (f) obtained as described above was evaluated in the same manner as in the above example. The evaluation results are shown in Table 2 below.
[0119]
[Table 2]

[0120]
From the results of Table 2 above, the ink jet recording sheets (b) to (e) obtained by drying with the film surface temperature of the coating film of 30 to 45 ° C. after the application of the cross-linking agent solution generated cracks and drying unevenness. A good surface shape was obtained. On the other hand, when the film surface temperature exceeded 45 ° C. (Reference Example 1), cracks occurred on the film surface, and when it was less than 25 ° C. (Reference Example 6), drying could not be completed.
[0121]
【The invention's effect】
According to the present invention, the ink receiving performance and other characteristics required for an ink jet recording sheet are provided, and the productivity (production efficiency) is improved without causing the colorant receiving layer to crack or gloss unevenness. Therefore, it is possible to provide a method for manufacturing an ink jet recording sheet capable of reducing the cost.
[Brief description of the drawings]
FIG. 1 is a schematic diagram illustrating a configuration example of a dryer including a slit nozzle.
FIG. 2 is a schematic diagram illustrating a configuration example of a floater dryer including a negative pressure type nozzle.
3A is a diagram showing a configuration example of a floater dryer in which positive pressure type nozzles are arranged on both sides of a web, and FIG. 3B is a diagram showing a configuration example of a floater dryer in which positive pressure type nozzles are arranged on one side of a web.
[Explanation of symbols]
1 ... Slit nozzle
2 ... Coating surface on support
3 ... Laura
4 ... Support with web (web)
5a, 5b, 5c ... Nozzle
6 ... Positive pressure type nozzle

Claims (5)

In the method for producing an inkjet recording sheet having a colorant receiving layer formed by applying and drying a coating liquid containing inorganic pigment fine particles and a water-soluble resin on a support,
The coating film having a water content of 1000 to 500% after coating is divided into two parts in the first half of the drying, the film surface speed of the drying air in the first half of the drying is 10 m / sec or less, and the film surface wind speed of the drying air in the second half of the drying is An ink jet recording sheet characterized in that drying is performed at a temperature higher than the film surface wind speed of the drying air in the first half of the drying , at a drying air temperature exceeding 30 ° C., and at a film surface temperature exceeding 20 ° C. Production method.   The method for producing an inkjet recording sheet according to claim 1, wherein at least one of a dryer having a slit nozzle having a nozzle tip located at a distance of 20 mm or more from the film surface and a floater dryer having a negative pressure type nozzle is used.   A coating liquid containing inorganic pigment fine particles and a water-soluble resin is coated on a support, and is in the middle of drying after coating, and a coating film having a water content of 1000 to 200% before the reduced drying rate is exhibited. The manufacturing method of the sheet | seat for inkjet recording of Claim 1 or 2 which provides the solution containing the crosslinking agent which can bridge | crosslink the said water-soluble resin, and a mordant.   A coating liquid containing inorganic pigment fine particles and a water-soluble resin is coated on a support, and is in the middle of drying after coating, and a coating film having a water content of 1000 to 200% before becoming a reduced rate drying rate. The solution according to any one of claims 1 to 3, wherein after applying a solution containing a crosslinking agent capable of crosslinking the water-soluble resin and a mordant, the coating film provided with the solution is dried at a film surface temperature of 25 to 50 ° C. A method for producing an ink jet recording sheet according to claim 1. 5. The inkjet recording according to claim 1, wherein the drying air temperature in the first half of the drying is 30 ° C. or more, and the drying air temperature in the second half of the drying is lower than the drying air temperature in the first half of the drying. Sheet manufacturing method.

Images