JP2005280294A - Sheet for inkjet recording - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet for inkjet recording whose long-term image conservation properties are significantly improved. <P>SOLUTION: This sheet contains a polymer having an ammonium salt unit represented by formula (1) wherein, R<SP>1</SP>is a hydrogen atom or a methyl group; R<SP>2</SP>is a divalent organic group; R<SP>3</SP>and R<SP>4</SP>are independently one kind selected from among a hydrogen atom, a 1-8C alkyl group and a benzyl group; Y- is an anionic residue; and n is an integer of 0 to 8. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an ink jet recording sheet, and more particularly, to an ink jet recording sheet having high image quality, high gloss, excellent ink absorbability, and excellent suppression of aging of recorded images over time in a high temperature and high humidity environment. .

The ink jet recording method that forms an image by ejecting liquid ink from a fine nozzle onto a recording body has low noise during recording, easy colorization, high-speed recording, and other printing It is widely used not only in offices such as terminal printers, facsimiles, plotters, and form printing, but also for so-called home use because it is more compact and relatively inexpensive than the apparatus. In addition, rapid progress in technology such as high-definition and high-speed printers has enabled commercial printing, further accelerating its spread.
On the other hand, as the performance of printers has improved, the appearance of digital cameras has been combined with the demand for advanced characteristics on the recording medium side. That is, there is a strong demand for an ink jet recording body that has both image absorbability and recording density, as well as image quality and storage stability comparable to silver salt photography.
In particular, the dye that is the main component of the ink decomposes in a relatively short period of time even when exposed to light from the sun, fluorescent lamps, and other oxidizing gases such as ozone, nitrogen oxides and sulfur oxides. However, ink-jet ink has the disadvantage that the recorded image is faded, and an approach to suppress or eliminate this is strongly desired for the recording medium. Similarly, since inkjet ink is generally water-soluble, it has a defect that the recorded image is inferior in moisture resistance and water resistance, and an improvement effort by a recording medium is indispensable.

  Therefore, in order to improve ink absorptivity, recording density, image quality, etc., for example, Japanese Patent Application Laid-Open Nos. 55-51583 (Patent Document 1) and 56-157 (Patent Document 2) disclose amorphous materials. A method of providing inorganic fine particles such as silica on a support together with a binder has been proposed.

  In order to obtain gloss and high image quality, it is proposed in Japanese Patent Publication No. 3-56552 (Patent Document 3), Japanese Patent Application Laid-Open No. 2-188287 (Patent Document 4) and the like to use synthetic silica fine particles. .

  Furthermore, in order to improve the storability of images, Japanese Patent Application Laid-Open No. 57-87987 (Patent Document 5) describes metal oxides such as phosphotungstic acid, phosphomolybdic acid, and chromic chloride, metal chlorides, or tannins. A method of adding at least one of the acids is described. JP-A-57-74192 (Patent Document 6), JP-A-61-14659 (Patent Document 7), JP-B 04-34512 (Patent Document 8) describes a method of adding an antioxidant such as hindered phenols and hindered amines, and JP-A-57-74193 (Patent Publication 9) and 57-87988. (Patent Publication 10) and 63-2222885 Publication (Patent Publication 11) disclose ultraviolet absorption such as benzophenone, benzotriazole, and phenylsalicylic acid. In addition, a method for adding a thiourea compound, a specific mercapto compound such as 2-mercaptobenzothiazole, 2-mercaptobenzimidazole, and the like is added to Japanese Patent Application Laid-Open No. 61-163886 (Patent Publication 12). Method, dithiocarbamate, thiuram salt, JP-A-7-314882 (Patent Publication 13), thiocyanate or thiocyanate, JP-A-60-257286 (Patent Publication 14) A method of adding basic polyaluminum hydroxide and a method of adding a zirconium oxychloride-based active inorganic polymer have been proposed in JP-A-4-7189 (Patent Publication 15).

  In order to improve water resistance, Japanese Patent Application Laid-Open No. 56-84992 (Patent Publication 16) proposes a method of incorporating a cationic polymer or basic latex in an ink receiving layer.

  Further, JP 2000-280611 A (Patent Publication 17) uses a hindered amine compound having a molecular weight in a specific range, so that the fixing of the dye and the water resistance of the recorded image can be achieved without including a cationic polymer in the ink receiving layer. In addition, there is disclosed a technique that can improve light resistance.

However, although full-color inkjet recording images formed using these techniques are excellent in image quality and ink absorbability, they are still insufficient for long-term storage, especially storage under high-temperature and high-humidity environments. Met.
JP-A-55-51583 JP-A-56-157 Japanese Patent Publication No. 3-56552 Japanese Patent Laid-Open No. 2-188287 JP-A-57-87987 JP-A-57-74192 JP-A 61-146591 Japanese Patent Publication No. 04-34512 JP-A-57-74193 JP-A-57-87988 Japanese Patent Laid-Open No. 63-222885 JP 61-163886 A JP 7-314882 A JP-A-60-257286 Japanese Patent Laid-Open No. 4-7189 JP 56-84992 A JP 2000-280611 A

  The present invention is an ink jet which has excellent image absorbability with high image quality, high gloss, excellent ink absorbability, and has greatly improved long-term storage stability of images, particularly in the suppression of blurring of recorded images over time in a high temperature and high humidity environment. An object is to provide a recording sheet.

The present inventors disclosed in Japanese Unexamined Patent Publication No. 2000-280611 “By adding a hindered amine compound having a molecular weight in a specific range to an ink jet recording sheet, fixing of a dye and water resistance of a recorded image can be achieved. As a result of intensive investigations to develop and improve the technology to achieve ", by including a polymer having an ammonium salt unit of a specific structure in an inkjet recording sheet, it is possible to achieve high image quality comparable to silver salt photography. The inventors have found that an ink jet recording sheet that is excellent in long-term image storage, particularly in suppressing blurring of recorded images over time in a high-temperature and high-humidity environment, has resulted in the completion of the present invention.
The present invention includes the following embodiments.
[1] An ink jet recording sheet comprising a polymer having an ammonium salt unit represented by the following general formula (1).

〔式中、Ｒ1は水素原子、またはメチル基を、Ｒ２は二価の有機基を表し、Ｒ３、およびＲ４はそれぞれ互いに独立に水素原子、炭素数が１〜８のアルキル基、ベンジル基から選ばれる一種を表し、Ｙ−は陰イオン残基を表し、ｎは０〜８の整数を表す。〕
［２］前記アンモニウム塩単位を有する重合体を含んでなるインクジェット記録用シートにおいて、前記アンモニウム塩単位を有する重合体が一般式（１）で表されるアンモニウム塩単位と、下記一般式（２）〜（４）で表される単位から選ばれる少なくとも一種類と、の共重合体であることを特徴とする［１］記載のインクジェット記録用シート。

[Wherein R1 represents a hydrogen atom or a methyl group, R2 represents a divalent organic group, and R3 and R4 are each independently selected from a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, and a benzyl group. Y- represents an anion residue, and n represents an integer of 0-8. ]
[2] In an inkjet recording sheet comprising a polymer having the ammonium salt unit, the polymer having the ammonium salt unit is an ammonium salt unit represented by the general formula (1), and the following general formula (2): The sheet for inkjet recording according to [1], which is a copolymer of at least one selected from units represented by (4) to (4).

〔式中、Ｒ５は水素原子、またはメチル基を表し、Ｒ６は、水素原子、または炭素数が１〜８の低級アルキル基から選ばれる一種を表す。〕

[Wherein, R5 represents a hydrogen atom or a methyl group, and R6 represents one selected from a hydrogen atom or a lower alkyl group having 1 to 8 carbon atoms. ]

〔式中、Ｒ７は水素原子、またはメチル基を表し、Ｒ８、およびＲ９は、互いに独立に水素原子、炭素数が１〜８の低級アルキル基から選ばれる一種を表すか、あるいはＲ８、およびＲ９は、互いに結合して、各々が結合している窒素原子とともに含窒素五員環構造、または含窒素六員環構造を形成していることを表す。〕

[Wherein R7 represents a hydrogen atom or a methyl group, and R8 and R9 each independently represent a hydrogen atom or a lower alkyl group having 1 to 8 carbon atoms, or R8 and R9] Are bonded to each other to form a nitrogen-containing five-membered ring structure or a nitrogen-containing six-membered ring structure together with the nitrogen atoms to which they are bonded. ]

〔式中、Ｒ１０は水素原子、またはメチル基を表し、Ｚは、水素原子、ヒドロキシル基、フェニル基、アセトキシ基、ホルムアミド基、アセトアミド基、カーバメート基、２−ピロリドニル基、またはシアノ基から選ばれる一種を表す。〕
［３］前記アンモニウム塩単位を有する重合体を含んでなるインクジェット記録用シートにおいて、前記アンモニウム塩単位を有する重合体の重量平均分子量が１０００以上、１００００００以下であることを特徴とする［１］、または［２］記載のインクジェット記録用シート。
［４］前記アンモニウム塩単位を有する重合体を含んでなるインクジェット記録用シートにおいて、インクジェット記録用シートが、無機微粒子と、水性高分子バインダーと、を各々少なくとも一種以上含有することを特徴とする［１］〜［３］記載のインクジェット記録用シート。
［５］前記無機微粒子のうち少なくとも一種が、一次粒子の平均粒経が３０ｎｍ以下である［４］記載のインクジェット記録用シート。
［６］前記無機微粒子のうち少なくとも一種が、気相法シリカである［４］、または［５］記載のインクジェット記録用シート。
［７］ 前記無機微粒子が、活性ケイ酸を縮合させて製造された湿式法微細シリカである［４］、または［５］記載のインクジェット記録用シート。
［８］前記無機微粒子のうち少なくとも一種が、一次粒子の平均粒経が３０ｎｍ以下であるシリカと、下記一般式（１）で表されるアンモニウム塩単位を有する重合体とのカチオン性複合微粒子であることを特徴とする［４］記載のインクジェット記録用シート。

[Wherein R10 represents a hydrogen atom or a methyl group, and Z is selected from a hydrogen atom, a hydroxyl group, a phenyl group, an acetoxy group, a formamide group, an acetamide group, a carbamate group, a 2-pyrrolidonyl group, or a cyano group. Represents a kind. ]
[3] In the inkjet recording sheet comprising the polymer having an ammonium salt unit, the polymer having the ammonium salt unit has a weight average molecular weight of 1,000 or more and 1,000,000 or less [1], Or the sheet | seat for inkjet recording as described in [2].
[4] The inkjet recording sheet comprising the polymer having an ammonium salt unit, wherein the inkjet recording sheet contains at least one or more inorganic fine particles and an aqueous polymer binder. The sheet for inkjet recording according to 1] to [3].
[5] The inkjet recording sheet according to [4], wherein at least one of the inorganic fine particles has an average primary particle size of 30 nm or less.
[6] The inkjet recording sheet according to [4] or [5], wherein at least one of the inorganic fine particles is gas phase method silica.
[7] The inkjet recording sheet according to [4] or [5], wherein the inorganic fine particles are wet process fine silica produced by condensing activated silicic acid.
[8] At least one of the inorganic fine particles is a cationic composite fine particle of silica having an average primary particle size of 30 nm or less and a polymer having an ammonium salt unit represented by the following general formula (1). The sheet for inkjet recording according to [4], which is characterized in that it exists.

〔式中、Ｒ1は水素原子、またはメチル基を、Ｒ２は二価の有機基を表し、Ｒ３、およびＲ４はそれぞれ互いに独立に水素原子、炭素数が１〜８のアルキル基、ベンジル基から選ばれる一種を表し、Ｙ−は陰イオン残基を表し、ｎは０〜８の整数を表す。〕
［９］前記無機微粒子のうち少なくとも一種が、一次粒子の平均粒経が３０ｎｍ以下であるシリカと、一般式（１）で表されるアンモニウム塩単位と、下記一般式（２）〜（４）で表される単位から選ばれる少なくとも一種類との共重合体、とのカチオン性複合微粒子であることを特徴とする［４］のインクジェット記録用シート。

[Wherein R1 represents a hydrogen atom or a methyl group, R2 represents a divalent organic group, and R3 and R4 are each independently selected from a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, and a benzyl group. Y- represents an anion residue, and n represents an integer of 0-8. ]
[9] At least one of the inorganic fine particles includes silica having an average primary particle size of 30 nm or less, an ammonium salt unit represented by the general formula (1), and the following general formulas (2) to (4). [4] The inkjet recording sheet according to [4], which is a cationic composite fine particle with at least one copolymer selected from units represented by:

〔式中、Ｒ５は水素原子、またはメチル基を表し、Ｒ６は、水素原子、または炭素数が１〜８の低級アルキル基から選ばれる一種を表す。〕

[Wherein, R5 represents a hydrogen atom or a methyl group, and R6 represents one selected from a hydrogen atom or a lower alkyl group having 1 to 8 carbon atoms. ]

〔式中、Ｒ７は水素原子、またはメチル基を表し、Ｒ８、およびＲ９は、互いに独立に水素原子、炭素数が１〜８の低級アルキル基から選ばれる一種を表すか、あるいはＲ８、およびＲ９は、互いに結合して、各々が結合している窒素原子とともに含窒素五員環構造、または含窒素六員環構造を形成していることを表す。〕

[Wherein R7 represents a hydrogen atom or a methyl group, and R8 and R9 each independently represent a hydrogen atom or a lower alkyl group having 1 to 8 carbon atoms, or R8 and R9] Are bonded to each other to form a nitrogen-containing five-membered ring structure or a nitrogen-containing six-membered ring structure together with the nitrogen atoms to which they are bonded. ]

〔式中、Ｒ１０は水素原子、またはメチル基を表し、Ｚは、水素原子、ヒドロキシル基、フェニル基、アセトキシ基、ホルムアミド基、アセトアミド基、カーバメート基、２−ピロリドニル基、またはシアノ基から選ばれる一種を表す。〕
［１０］支持体が、紙であることを特徴とする［１］〜［９］のいずれか一項に記載のインクジェット記録用シート。
［１１］支持体が、耐水性支持体である［１］〜［９］のいずれか一項に記載のインクジェット記録用シート。
［１２］前記耐水性支持体が、紙の両面をポリオレフィン樹脂で被覆された支持体である［１１］記載のインクジェット記録用シート。
［１３］インクジェット記録用シートがキャスト処理されたインク受容層を有する［１］〜［１２］のいずれか一項に記載のインクジェット記録用シート。
［１４］インクジェット記録用シートがインク受容層よりも上層にキャスト処理によって形成された光沢発現層を有する［１］〜［１３］のいずれか一項に記載のインクジェット記録用シート。

[Wherein R10 represents a hydrogen atom or a methyl group, and Z is selected from a hydrogen atom, a hydroxyl group, a phenyl group, an acetoxy group, a formamide group, an acetamide group, a carbamate group, a 2-pyrrolidonyl group, or a cyano group. Represents a kind. ]
[10] The ink jet recording sheet according to any one of [1] to [9], wherein the support is paper.
[11] The ink jet recording sheet according to any one of [1] to [9], wherein the support is a water resistant support.
[12] The inkjet recording sheet according to [11], wherein the water-resistant support is a support in which both surfaces of paper are coated with a polyolefin resin.
[13] The ink jet recording sheet according to any one of [1] to [12], wherein the ink jet recording sheet has an ink receiving layer subjected to a cast treatment.
[14] The ink jet recording sheet according to any one of [1] to [13], wherein the ink jet recording sheet has a glossy expression layer formed by a casting process above the ink receiving layer.

  An ink jet recording sheet comprising a polymer having an ammonium salt unit having a specific structure according to the present invention has a high recording density, forms a high-quality image, and is capable of recording images over time even in a high-temperature and high-humidity environment. The ink jet recording sheet was excellent in storability and excellent in water resistance with little occurrence of blurring or discoloration.

  The ink jet recording sheet of the present invention is characterized by comprising a polymer having a specific ammonium salt unit. Hereinafter, the polymer which has a specific ammonium salt unit is demonstrated first.

  The polymer having a specific ammonium salt unit used in the present invention is a polymer having an ammonium salt unit represented by the following general formula (1).

一般式（１）中、Ｒ1は、水素原子、またはメチル基から選ばれることが好ましく、Ｒ２は、二価の有機基を表すが、例えば、アルキレン基、アリ−レン基、アラルキレン基などから選ばれる二価の有機基であり、エチレン基、またはプロピレン基であることが好ましい。また、式中、ｎは０〜８の整数を表すが、好ましくは、０〜４の整数である。さらに、Ｒ３、およびＲ４は、式中で、それぞれ互いに独立に水素原子、炭素数が１〜８のアルキル基、ベンジル基から選ばれる一種を表すが、具体的には、水素原子、メチル基、エチル基、アリル基、ｎ−プロピル基、イソプロピル基、ｎ−ブチル基、イソブチル基、ｓｅｃ−ブチル基、ｔ−ブチル基、ｎ−ヘキシル基、シクロヘキシル基、オクチル基、２−エチルヘキシル基、ベンジル基などから選ばれる置換基であって、好ましくは、Ｒ３、Ｒ４が共に水素原子、メチル基、エチル基、ベンジル基から選ばれる一種であるか、または、Ｒ３とＲ４とが、各々、水素原子、メチル基、エチル基、ベンジル基から選ばれる異なる置換基の組み合わせである。
この他、一般式（１）で、Ｙ−は陰イオン残基を表すが、特に限定はなく、例えば、有機酸残基、あるいは無機酸残基を表す。有機酸残基としては、例えば、Ｒ−ＣＯＯ-、Ｒ−ＯＳＯ2-、などの一般式で示されるカルボン酸類、スルホン酸類などが挙げられ（上記Ｒは、アルキル基、例えばメチル基、エチル基、ｎ−プロピル基、イソプロピル基、ｎ−ブチル基、イソブチル基、ｓｅｃ−ブチル基、ｔ−ブチル基、ｎ−ヘキシル基、シクロヘキシル基、２−エチルヘキシル基、ｎ−デシル基、ｎ−ドデシル基、オクタデシル基と、これらの誘導体置換基など、アラルキル基、例えばベンジル基、フェニルエチル基、ビニルベンジル基、１−フェニルビニル基、ヒドロキシフェニルメチル基など、あるいは、アリール基、例えばフェニル基、ナフチル基、トリル基、クロロフェニル基、ジクロロフェニル基、トリクロロフェニル基、ブロモフェニル基、ヒドロキシフェニル基、メトキシフェニル基、アセトキシフェニル基、シアノフェニル基、ビニルフェニル基などから選ばれる置換基を表す）、より具体的には、ぎ酸残基、酢酸残基、ハロゲン化酢酸残基、メタンスルホン酸硫酸残基、トルエンスルホン酸残基などを挙げることができる。また、無機酸残基としては、ハライド類（Ｃｌ-、Ｆ-、Ｂｒ-、Ｉ-）、ＮＯ_３-、ＨＳＯ_４-、ＣＨ_３ＳＯ_４-、ＥｔＳＯ_４-、Ｈ_２ＰＯ_４-、ＣｌＯ_４-、ＢＦ_４-、ＰＦ_６-などを挙げることができる。

In the general formula (1), R 1 is preferably selected from a hydrogen atom or a methyl group, and R 2 represents a divalent organic group, and is selected from, for example, an alkylene group, an arylene group, an aralkylene group, and the like. The divalent organic group is preferably an ethylene group or a propylene group. In the formula, n represents an integer of 0 to 8, and preferably an integer of 0 to 4. Furthermore, R3 and R4 each independently represent a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or a benzyl group independently of each other, specifically, a hydrogen atom, a methyl group, Ethyl group, allyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, t-butyl group, n-hexyl group, cyclohexyl group, octyl group, 2-ethylhexyl group, benzyl group Preferably, R3 and R4 are both selected from a hydrogen atom, a methyl group, an ethyl group, and a benzyl group, or R3 and R4 are each a hydrogen atom, A combination of different substituents selected from a methyl group, an ethyl group, and a benzyl group.
In addition, in the general formula (1), Y- represents an anion residue, but is not particularly limited, and represents, for example, an organic acid residue or an inorganic acid residue. Examples of the organic acid residue include carboxylic acids and sulfonic acids represented by general formulas such as R-COO- and R-OSO2- (wherein R represents an alkyl group such as a methyl group, an ethyl group, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, t-butyl, n-hexyl, cyclohexyl, 2-ethylhexyl, n-decyl, n-dodecyl, octadecyl And aralkyl groups such as benzyl, phenylethyl, vinylbenzyl, 1-phenylvinyl, hydroxyphenylmethyl, or aryl groups such as phenyl, naphthyl, and tolyl Group, chlorophenyl group, dichlorophenyl group, trichlorophenyl group, bromophenyl group, hydroxyphenyl Represents a substituent selected from a group, a methoxyphenyl group, an acetoxyphenyl group, a cyanophenyl group, a vinylphenyl group, and the like. More specifically, a formic acid residue, an acetic acid residue, a halogenated acetic acid residue, methanesulfone An acid sulfuric acid residue, a toluenesulfonic acid residue, etc. can be mentioned. Examples of the inorganic acid residues, halides (Cl-, F-, Br-, I -), NO 3 -, HSO 4 -, CH 3 SO 4 -, EtSO 4 -, H 2 PO 4 -, ClO _{4 -, BF 4 -, PF} 6 - and the like.

  The polymer having a specific ammonium salt unit used in the inkjet recording sheet of the present invention is a kind of cationic polymer that captures and fixes a basic dye in an inkjet ink called a fixing agent or a mordant. As represented by the formula (1), it is important to have a structure in which the ammonium salt portion is surrounded by four methyl groups substituted on adjacent carbon atoms. Excellent recorded image storability under is achieved. Although there are many uncertainties in the preservation of excellent recorded images under high temperature and high humidity, the ammonium salt moiety that captures the dye is surrounded by four methyl groups substituted on adjacent carbon atoms. Therefore, it is assumed that the vicinity is hydrophobized and the approach of moisture is suppressed.

  The polymer having an ammonium salt unit contained in the ink jet recording sheet of the present invention represented by the general formula (1) can be easily synthesized by a conventional method. For example, the polymer represented by the following general formula (5) It can be obtained by polymerizing the ammonium salt monomer represented, or polymerizing the monomer represented by the following general formula (6) to form a polymer having an amino group, and then treating with an acid or halide. .

  In addition, the polymer having an ammonium salt unit of the present invention is not particularly limited except that it contains an ammonium salt unit represented by the general formula (1), and a polymer composed only of the ammonium salt unit of the general formula (1). Even if it is a polymer (a homopolymer or a copolymer comprising two or more different units of R1 to R4, n, and Y-), or as long as the performance as an inkjet recording sheet is not impaired, It may be a copolymer obtained by polymerizing the ammonium salt unit of the general formula (1) and other components. That is, for the synthesis of the polymer containing the ammonium salt unit represented by the general formula (1) of the present invention, only the monomer represented by the general formula (5) or (6) can be used alone. In addition, two or more different monomers represented by the general formulas (5) and / or (6) of R1 to R4, n, and Y- may be used at the same time. Other monomers that can be copolymerized with the monomer represented by the general formula (5) and / or (6) may be used together as long as the performance as a polymer is not impaired.

In order to obtain a polymer containing an ammonium salt unit represented by the general formula (1), a hindered amine type antioxidant (reactive HALS) having a (meth) acryloyl group can be suitably used. As a commercial item, ADK STAB LA-82 (Asahi Denka), ADK STAB LA-87 (Asahi Denka), etc. can be used. As another method, T.W. Kurosaki et.al. , J .; Poly. Sci. Part A-1, 10 (11), 3295 (1972), W.M. Liang et. al. , Polymer Degradation and Stability, 31 (3), 353 (1991), X. Liu et. al. , Polymers for Advanced Technologies, 13 (3-4), 247 (2002), and the like, and a monomer represented by the general formula (5) or (6) is synthesized and subjected to a polymerization reaction. The polymer containing the ammonium salt unit represented by the general formula (1) of the present invention can also be obtained.

  As described above, the polymer containing an ammonium salt unit represented by the general formula (1) of the present invention includes a monomer represented by the general formula (5) or (6) and other monomers copolymerizable therewith. The other monomer that can be copolymerized with the monomer represented by the general formula (5) or (6) is an ammonium represented by the general formula (1) of the present invention. The monomer is not particularly limited as long as it is a monomer capable of forming a polymer containing a salt unit. Examples thereof include olefins such as ethylene and propylene, styrenes such as styrene, α-methylstyrene and vinyltoluene, and vinyl acetate. , Ethylenically unsaturated esters of fatty acids such as allyl acetate, methyl (meth) acrylate, ethyl (meth) acrylate, benzyl (meth) acrylate, hydroxyethyl (meth ) Acrylate, methoxypolyethylene glycol (meth) acrylate, methoxypolypropylene glycol (meth) acrylate, (meth) acrylic acid esters such as (meth) acryloylmorpholine, (meth) acrylamide, N -(Meth) acrylamides such as methyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diisopropyl (meth) acrylamide, acrylonitrile, N-vinylpyrrolidone, N-vinylformate, N-vinyl Examples thereof include monoethylenically unsaturated compounds such as acetonate, N-vinyl-methyl carbamate, N-vinyl-ethyl carbamate, and N-vinyl-phenyl carbamate.

  When the polymer containing an ammonium salt unit represented by the general formula (1) of the present invention is used as a copolymer, the monomer represented by the general formula (5) or (6) and other monomers to be copolymerized are used. The copolymerization ratio with-can be arbitrarily set within a range that does not impair the performance as an inkjet recording sheet. However, when the content of the ammonium salt unit represented by the general formula (1) is smaller than 5 mol% in the entire copolymer, water resistance and moisture resistance may be insufficient.

  The polymer containing an ammonium salt unit represented by the general formula (1) of the present invention polymerizes the monomer represented by the general formula (5) or (6) by a conventional method, or the general formula (5), Alternatively, it can be obtained by copolymerizing the monomer represented by (6) and another monomer, and its (weight average) molecular weight can be arbitrarily set. However, when the molecular weight is less than 1000, the water resistance and moisture resistance tend to be insufficient, and when it is 1000000 or more, the viscosity becomes high, and the handling ability may be poor.

  Synthesis and production of the polymer containing an ammonium salt unit represented by the general formula (1) of the present invention is carried out by a known polymerization method. For example, solution polymerization, emulsion polymerization, reverse phase emulsion polymerization, suspension polymerization, It is made by bulk polymerization, precipitation polymerization or the like. The polymerization is started by conventional methods and various methods. For example, the polymerization is performed by a thermal polymerization method, a cationic polymerization method, an anionic polymerization method, a method of irradiating light or energy rays, and suitable for each method. Various polymerization initiators such as radical polymerization initiators and redox polymerization agents are used.

  The ink jet recording sheet of the present invention is required to contain a polymer containing an ammonium salt unit represented by the general formula (1) of the present invention. In addition to containing a polymer containing an ammonium salt unit represented by the general formula (1), there is no particular limitation on its embodiment. The polymer containing an ammonium salt unit represented by the general formula (1) of the present invention can be contained in an ink jet recording sheet by any method, and for example, absorbability such as paper, cloth, or nonwoven fabric. A method of directly applying, impregnating or spraying a solution / dispersion containing a polymer containing an ammonium salt unit represented by the general formula (1) on a substrate having the general formula (1), and a general formula (1) on a support A method of coating an ink receiving layer containing a polymer containing an ammonium salt unit, or a polymer containing an ammonium salt unit represented by the general formula (1) on an ink receiving layer provided on a support The ink jet recording sheet of the present invention can be produced by a method of applying, impregnating, or spraying a solution / dispersion solution containing the above.

  In the production of the ink jet recording sheet of the present invention, an adhesive is applied to a water-absorbing substrate such as paper (acidic paper, neutral paper, coated paper), cloth, or non-woven fabric, coated paper or high-quality paper. Suitable for low water-permeable substrates laminated with plastic film, or water-resistant substrates such as laminated paper with plastic film, sheet, synthetic paper, and paper as the core, and the surface covered with plastic Can be used.

  In recent years, in order to give the inkjet recording sheet of the present invention image quality and gloss comparable to silver salt photographs, which have been increasing in demand, as a base material, a water-resistant base material, in particular, both sides of the base paper are made of polyethylene or the like. So-called RC paper laminated with a polyolefin resin is particularly preferably used.

In the ink jet recording sheet of the present invention, for example, a polymer solution / dispersion liquid containing an ammonium salt unit represented by the general formula (1) directly based on water-absorbing paper or coated paper is used. The content of the polymer containing the ammonium salt unit represented by the general formula (1) in the ink jet recording sheet of the present invention obtained by coating, impregnating, or spraying has the performance as a sheet for ink jet recording. Although it can be arbitrarily set within a range not to be damaged, if the dry solid content per 1 m ^{2 of} the base material is less than 0.05 g, not only the water resistance and moisture resistance of the recorded image become insufficient, but also ink (dye). However, when the dry solid content per 1 m ^{2 of the} substrate exceeds 5 g, the effect is saturated and may not be practical, which is not preferable.

As another aspect of the ink jet recording sheet of the present invention, for example, the ink jet recording sheet of the present invention contains a polymer containing an ammonium salt unit represented by the general formula (1), and is exemplified above. In the case of a substrate comprising a substrate and an ink receiving layer containing inorganic fine particles and an aqueous polymer binder on the surface thereof, the ink receiving layer does not necessarily need to be a single layer, and there are two or more layers. In addition, a gloss developing layer may be provided for the purpose of imparting and developing gloss to an upper layer than the ink receiving layer, and the coating amount of each layer after drying is the sheet for inkjet recording. In the case of an ink receiving layer, the total coating amount of each layer is about ² to 50 g / m ² , and in the case of a glossy layer, it is 0.2 to 30 g / m. ² It is preferable that it is a grade. Incidentally, if the total coating amount of each layer of the ink receiving layer is less than 2 g / m ² , not only the recording image quality and the coating film strength may be inferior, but also the fixing property of the ink (dye) may not remain. On the other hand, if it is attempted to increase the coating amount beyond 50 g / m ² , the ink receiving layer is likely to crack, and the recording image quality may be drastically deteriorated. Similarly, when the coating amount of the glossy layer is less than 0.2 g / m ² , the glossiness may be impaired, and light interference fringes due to the Newton effect are likely to occur. However, if the coating amount exceeds 30 g / m ² , the ink absorptivity may be remarkably deteriorated.

  An ink jet recording sheet containing a polymer containing an ammonium salt unit represented by the general formula (1) of the present invention includes, for example, a support, inorganic fine particles on the surface thereof, and an aqueous polymer binder. In the case where it is composed of a receiving layer, examples of inorganic fine particles to be contained in the ink receiving layer include zeolite, light calcium carbonate, heavy calcium carbonate, magnesium carbonate, kaolin, talc, calcium sulfate, barium sulfate, titanium oxide, and oxidation. Zinc, zinc sulfide, zinc carbonate, satin white, aluminum silicate, diatomaceous earth, calcium silicate, magnesium silicate, silica, aluminum hydroxide, alumina, alumina hydrate, aluminosilicate, boehmite, pseudoboehmite, etc. However, silica is particularly preferable in terms of ink absorbability.

  Synthetic silica is classified into a wet method and a gas phase method. As the wet process silica, (1) silica sol obtained through acid decomposition of sodium silicate and ion exchange resin layer, (2) colloidal silica obtained by heating and aging silica sol, (3) porous obtained by condensation of silica sol Silica fine particles (4) Silica gel, which is gelled from silica sol and formed into three-dimensional secondary particles of several to 10 microns, with primary particles bonded to siloxane, (5) Heating silica gel, sodium silicate, sodium aluminate, etc. A synthetic silicic acid compound mainly composed of silicic acid obtained, and (6) after adding alkali to a colloidally dispersed silica seed solution, the seed solution is at least selected from an active silicic acid aqueous solution and an alkoxysilane. Secondary obtained by growing silica fine particles by adding a small amount of one kind of feed liquid Rika dispersion (JP 2001-354408) and the like.

  Vapor phase method silica is called dry method for wet method and is made by flame hydrolysis method. Specifically, silicon tetrachloride is produced by burning with hydrogen and oxygen. Instead of silicon tetrachloride, silanes such as methyltrichlorosilane and trichlorosilane may be used alone or mixed with silicon tetrachloride.

The average particle size of the primary particles of the inorganic fine particles used in the present invention is not particularly limited, but it is preferably 30 nm or less, more preferably 3 to 3 nm in consideration of printing quality such as transparency and low granularity. 15 nm. On the other hand, the specific surface area of the inorganic fine particles used in the present invention is not particularly limited, but the specific surface area by the BET method is 200 m in order to minimize the granularity of the recorded image due to the ink absorption speed and the ink absorption amount. It is preferably ² / g or more, more preferably 250 to 500 m ² / g. Although there is no upper limit to the specific surface area by the BET method, it is preferably about 1000 m ² / g or less.
The BET method referred to in the present invention is one of powder surface measurement methods by vapor phase adsorption, and is a method for determining the total surface area, that is, the specific surface area of a 1 g sample from an adsorption isotherm.
In addition, from the viewpoint of obtaining ink absorbability, transparency, and high gloss, the inorganic fine particles used in the present invention are preferably vapor-phase process silica. Further, when inorganic fine particles such as synthetic silica are aggregated, the aggregated particle diameter is not particularly limited, but is preferably 0.05 to 10 μm in consideration of glossiness of the inkjet recording sheet itself or the recorded image. More preferably, it is 0.05-7.0 micrometers.

  In the ink jet recording sheet of the present invention, the amount of inorganic fine particles used in the ink receiving layer is not particularly limited, but the coating strength of the ink receiving layer, the ink absorbability, the ink drying property, and the ink jet recording sheet. In view of the recording image quality, it is preferably about 20 to 95% by mass, more preferably about 30 to 90% by mass with respect to the solid content of the ink receiving layer.

In the inkjet recording sheet having the support and the ink receiving layer on the support of the present invention, the content of the polymer containing the ammonium salt unit represented by the general formula (1) in the ink receiving layer is it is not particularly limited, that in order to stably exhibit an excellent inhibitory effect against bleeding with time of the recorded images in high-temperature, high-humidity environment is 0.02g / m ² ~25g / m ² Preferably, it is 0.05 g / m ² to ²⁰ g / m ² . When the content of the polymer containing an ammonium salt unit represented by the general formula (1) used in the present invention is within this range, the ink jet recording sheet of the present invention is an ink receiving layer. It is possible to provide a high-quality recorded image having an excellent appearance with no cracks on the surface and excellent ink absorbability.

  In the inkjet recording sheet of the present invention having a support and an ink-receiving layer on the support, the inkjet recording sheet contains a polymer containing an ammonium salt unit represented by the general formula (1). Is, for example, a method of coating an ink receiving layer containing a polymer containing an ammonium salt unit represented by the general formula (1) on a support, or a general formula on an ink receiving layer provided on a support. As described above, there is a method of applying, impregnating, or spraying a solution / dispersion containing a polymer containing an ammonium salt unit represented by (1). As an example of a method for incorporating a polymer containing an ammonium salt unit into an ink receiving layer, a polymer containing an ammonium salt unit represented by the general formula (1) is added to the ink receiving layer coating material. More specifically, for example, a method of adding a polymer containing an ammonium salt unit represented by the general formula (1) at the time of dispersion of inorganic fine particles to be contained in a prepaint, or a general method for a final paint Examples thereof include a method of adding a polymer containing an ammonium salt unit represented by the formula (1), and it is preferable to determine the addition method, the order of addition, etc. in consideration of the stability of the coating material.

  In the present invention, various known cationic polymers can be contained in the substrate, the support or the ink receiving layer as long as the performance as an ink jet recording sheet is not impaired. The known cationic polymer is usually a homopolymer of a monomer (monomer) having a primary to quaternary ammonium salt, a monomer having the primary to quaternary ammonium salt, and other than these. It can be easily obtained as a copolymer with a monomer or a condensation polymer. The known cationic polymer can be used in the form of either an aqueous solution or an aqueous dispersion (body), and an aqueous solution and / or dispersion (body) of two or more kinds of cationic polymers can be used simultaneously.

  There is no restriction | limiting in particular in the cationic polymer used for this invention, Various well-known cationic polymers can be used.

Specific examples of various known cationic polymers include 1) polyalkylene polyamines such as polyethylene polyamine and polypropylene polyamine or derivatives thereof, and 2) acrylics having secondary amino groups, tertiary amino groups, and quaternary ammonium groups. Polymers, 3) Polyvinylamine and polyvinylamidines, 4) Dicyan cationic polymer represented by dicyandiamide / formalin copolymer, 5) Polyamine cationic polymer represented by dicyandiamide / polyethyleneamine copolymer, 6) Epichlorohydrin dimethylamine copolymer, 7) diallyldimethylammonium -S0 ₂ double condensate, 8) diallylamine salt-S0 ₂ double condensate, 9) diallyldimethyl ammonium chloride polymers, 10) diallyldimethylammonium Ride-acrylamide copolymer, 11) Allylamine salt copolymer, 12) Dialkylaminoethyl (meth) acrylate quaternary salt copolymer, 13) Acrylamide-diallylamine copolymer, 14) 5-membered ring amidine structure And cationic polymers.

  Among these various known cationic polymers, diallyldimethylammonium chloride polymer, diallyldimethylammonium chloride-acrylamide copolymer, and alkyl (including aralkyl) halide of poly (meth) acryloyloxyalkyldialkylamine, which are excellent in color development characteristics and color reproducibility. Of (meth) acryloyloxyalkyldialkylamine alkyl (including aralkyl) halide salt / acrylamide copolymer, poly (meth) acrylamide alkyldialkylamine alkyl (including aralkyl) halide salt, (meth) acrylamide alkyldialkylamine Cationic polymers containing quaternary ammonium salts such as alkyl (including aralkyl) halide salts and acrylamide copolymers, and excellent storage stability of recorded images Polydiallylamine hydrochloride, polydiallylamine sulfate, polydiallylamine phosphate, polydiallylamine acetate, polydiallylamine propionate, polydiallylamine methanesulfonate, poly (di-2-methylallylamine) Hydrochloride), poly (di-2-methylallylamine sulfate), diallylamine hydrochloride / acrylamide copolymer, diallylamine sulfate / acrylamide copolymer, diallylamine phosphate / acrylamide copolymer, diallylamine methanesulfonic acid Salt / acrylamide copolymer, diallylamine hydrochloride / sulfur dioxide copolymer, diallylamine sulfate / sulfur dioxide copolymer, polyallylamine hydrochloride, polyallylamine sulfate, polyallylamine methanesulfonate, allyl Mine hydrochloride / acrylamide copolymer, allylamine sulfate / acrylamide copolymer, allylamine methanesulfonate / acrylamide copolymer, allylamine hydrochloride / diallylamine hydrochloride copolymer, allylamine methanesulfonate / diallylamine Methanesulfonate copolymer, polyvinylamine hydrochloride, vinylamine hydrochloride / acrylamide copolymer, polyvinylamine hydrochloride / polyvinyl alcohol copolymer, poly-N-vinylacrylamidine hydrochloride, N-vinylacrylamidine hydrochloride・ Acrylamide copolymer, N-vinylacrylamidine hydrochloride, acrylonitrile, N-vinylacrylamide, vinylamine hydrochloride, N-vinylformamide copolymer, N-vinylacrylamidine hydrochloride, acrylamide, Acrylonitrile / N-vinylacrylamide / vinylamine hydrochloride / N-vinylformamide copolymer, dicyandiamide / formalin polycondensate, polyalkylenepolyamine / dicyandiamide polycondensate, polyethyleneimine hydrochloride, poly (meth) acryloyloxyalkylamine hydrochloride , (Meth) acryloyloxyalkylamine hydrochloride / acrylamide copolymer, poly (meth) acrylamide alkylamine hydrochloride, (meth) acrylamide alkyldialkylamine hydrochloride / acrylamide copolymer, etc. A cationic polymer containing a quaternary ammonium salt is also preferably used in the present invention.

When a cationic polymer is used in the present invention, the molecular weight is preferably about 5,000 to 1,000,000, more preferably about 10,000 to 300,000.
When using a cationic polymer for this invention, as its usage-amount, 1-1000 mass parts is preferable with respect to 100 mass parts of polymers containing the ammonium salt unit represented by General formula (1) of this invention, More preferably Is 10 to 900 parts by mass.

When the ink jet recording sheet of the present invention is composed of a support, an ink receiving layer containing inorganic fine particles on the surface thereof, and an aqueous polymer binder, the aqueous polymer binder used in the ink receiving layer Is not particularly limited, for example, starch derivatives such as oxidized starch and etherified starch, cellulose derivatives such as carboxymethylcellulose and hydroxyethylcellulose, proteins such as casein, gelatin and soy protein, completely (partially) saponified polyvinyl alcohol , Polyvinyl alcohols such as silicon-modified polyvinyl alcohol, acetoacetyl group-modified polyvinyl alcohol, cation-modified polyvinyl alcohol, styrene-butadiene latex, acrylic latex, polyester latex, polyurethane latex , Synthetic latex such as a vinyl acetate-based latex, other, polyvinylpyrrolidone, styrene - salts of maleic anhydride copolymers, and the like can be used.
Among these aqueous binders, polyvinyl alcohols such as completely (partially) saponified polyvinyl alcohol, silicon-modified polyvinyl alcohol, acetoacetyl group-modified polyvinyl alcohol, and cation-modified polyvinyl alcohol, or polyurethane latex are more preferably used.

  When polyvinyl alcohols are used in the present invention, among saponified polyvinyl alcohols, partially saponified polyvinyl alcohol having a saponification degree of 80% or more, fully saponified polyvinyl alcohol, or silicon-modified polyvinyl alcohol is preferable. 200-5,000 are preferable and 500-5,000 are more preferable.

Polyvinyl alcohol is preferable because it has high transparency and water resistance among water-based binders, is nonionic, can be mixed with various materials, and has a relatively low swellability around room temperature. In addition, there is an advantage that the ink does not swell at the initial permeation of the ink and does not block the gap.
The reason why partially saponified polyvinyl alcohol having a saponification degree of 80% or more or completely saponified polyvinyl alcohol is preferable is excellent water resistance, and silicon-modified polyvinyl alcohol is preferable because of its high water resistance and inorganic pigment. Good adhesion to fine particles.
The reason why the average degree of polymerization of partially saponified polyvinyl alcohol having a saponification degree of 80% or more, fully saponified polyvinyl alcohol, or silicon-modified polyvinyl alcohol is preferable among the polyvinyl alcohols is that the degree of polymerization in this range. This is because when a product is used, the viscosity is excellent in water resistance and easy to handle.

  The polyurethane latex is preferably a self-emulsifying cationic polyurethane latex having a primary to quaternary ammonium base in the main chain or side chain.

  These aqueous polymer binders are generally used in an amount of about 1 to 100 parts by mass, preferably about 5 to 50 parts by mass with respect to 100 parts by mass of the inorganic fine particles.

  In the present invention, a crosslinking agent can be used together with the aqueous polymer binder. The crosslinking agent is not particularly limited, but specific examples include boric acid, borax, borate, glyoxal, melamine / formaldehyde, glutaraldehyde, methylol urea, polyisocyanate compound, epoxy compound, aziridine compound, carbodiimide compound, dihydrazide Examples thereof include a compound and a zirconium compound. Of these, boric acid, borax, or borate is preferable.

  In the present invention, it is also possible to use a phosphorus oxoacid salt as a stabilizer for the coating material forming the ink receiving layer. As the stabilizer, there is no particular limitation on the phosphorus oxoacid salt. Specific examples thereof include phosphoric acid, phosphorous acid, hypophosphorous acid, metaphosphoric acid, metaphosphorous acid, pyrophosphoric acid, pyrophosphorous acid. And alkali metal salts such as polyphosphoric acid, alkaline earth metal salts, ammonium salts, and zinc salts.

  Of these, hypophosphite is preferably used because it is particularly effective in coating stability. Specific examples of hypophosphites include sodium hypophosphite, potassium hypophosphite, calcium hypophosphite, magnesium hypophosphite, barium hypophosphite, ammonium hypophosphite, zinc hypophosphite In particular, sodium hypophosphite is most preferably used because it has the highest effect on paint stability.

  Further, when the ink jet recording sheet of the present invention has an ink receiving layer, various known pigment dispersants, thickeners, fluidity modifiers, antifoaming agents, antifoaming agents, release agents are contained in the ink receiving layer. Molding agents, foaming agents, penetrants, coloring dyes, coloring pigments, fluorescent brighteners, preservatives, antibacterial agents, water resistance agents, image stabilizers, and the like can be added as appropriate.

When the ink jet recording sheet of the present invention has an ink receiving layer, the ink receiving layer is formed by coating the ink receiving layer with a coating method such as a bar coater, a blade coater, an air knife coater, a gravure coater, a die coater, or a curtain coater. It is formed by coating and drying on at least one side of the support so that the coating amount after drying is about ² to 50 g / m ² . Incidentally, when the coating amount is within this range, the recording image quality and the coating film strength are excellent.
For the purpose of imparting high gloss after the ink receiving layer is formed, it is also possible to impart surface smoothness through the roll nip under pressure with a super calender, gloss calender, or the like.

  In addition, an ink jet recording sheet having a higher surface glossiness can be produced by providing a glossy expression layer above the ink receiving layer and casting, or by directly casting the ink receiving layer itself. it can. This gloss-expressing layer contains a resin or a pigment and a resin, and is porous or liquid-permeable so long as the gloss does not decrease so that the ink can be absorbed and passed quickly and does not hinder the absorption in the ink receiving layer. It is preferable to make it. For that purpose, the gloss developing layer is formed by selecting a drying condition that does not completely form the resin blended in the gloss developing layer by adding a pigment to the gloss developing layer within a range not deteriorating the gloss. Is preferred.

  Examples of the pigment used for the glossy layer include the same pigments as those used for the ink receiving layer, but in terms of gloss, transparency and ink absorbability, colloidal silica, amorphous silica, aluminum oxide, aluminosilicate, Zeolite, synthetic smectite and the like are preferable. These pigments are desirably contained in the glossy layer in an amount of 10 to 95% by mass. The average particle diameter of the pigment (in the case of aggregated particles, the diameter of the aggregated particles) is preferably 0.001 to 1 μm, and more preferably 0.005 to 0.5 μm. When the particle diameter is in this range, excellent ink absorbability, glossiness, and printing density can be obtained.

  Examples of the resin used for the glossy layer include water-soluble binders (for example, polyvinyl alcohols such as polyvinyl alcohol, cation-modified polyvinyl alcohol, and silicon-modified polyvinyl alcohol, casein, soy protein, synthetic proteins, starch, carboxymethyl cellulose, and methyl cellulose). Cellulose derivatives), styrene-butadiene copolymers, conjugated diene polymer latexes such as methyl methacrylate-butadiene copolymers, water-dispersible resins such as vinyl copolymer latexes such as styrene-vinyl acetate copolymers, In addition, various publicly known resins (adhesives) such as water-based acrylic resins, water-based polyurethane resins, and water-based polyester resins can be exemplified, and these can be used alone or in combination of two or more.

  In the case of forming a glossy expression layer mainly composed of a resin, a polymer or copolymer (hereinafter collectively referred to as a polymer) obtained by polymerizing a monomer having an ethylenically unsaturated bond (hereinafter referred to as an ethylenic monomer). Resin), and a substituted derivative of these polymers may be used. In addition, the above ethylenic monomer is polymerized in the presence of colloidal silica to form a composite by Si—O—R (R: polymer component) bond, or the polymer is colloidal silica such as SiOH group and the like. A functional group capable of reacting may be introduced and used in the form of a composite by reacting with colloidal silica. When this composite is used, it tends to be excellent in gloss and ink absorbability.

  When forming a glossy expression layer by a casting method, the glass transition point of the resin is preferably −25 ° C. or higher, more preferably −20 to 100 ° C. If the glass transition point is too low, the film formation proceeds too much during drying, resulting in a risk of decreasing the ink absorption rate, but conversely, if the glass transition point is too high, A large number of unintentional cracks are generated, and not only the surface gloss is lowered, but also the ink absorption is made non-uniform, and as a result, the recording image quality may be lowered. In addition, when forming a glossy layer by the cast method, the processing / drying temperature is also important, and if the processing / drying temperature is too high, the film formation proceeds too much and the surface porosity decreases, resulting in a decrease in the ink absorption rate. Conversely, if the drying temperature is too low, the gloss tends to be poor, and the productivity also decreases.

  Examples of the method for forming the gloss developing layer on the inkjet recording sheet of the present invention by a casting method include a wet casting method, a gelation casting method, and a rewet casting method, all of which are coating liquid layers of the gloss developing layer on the mirror drum surface. A step of constrained drying. That is, the wet method is a technique for performing a high gloss finish by pressing the gloss developing layer against a heated mirror drum surface while the gloss developing layer coating solution applied on the substrate is in a wet state. In the gelation method, while the gloss developing layer coating solution applied on the substrate is in a wet state, the gloss developing layer coating solution is brought into contact with the gelling solution to heat the gloss developing layer in a gelled state. A high gloss finish is applied by pressing against the mirror drum surface. Further, the rewet method is a method in which a glossy layer in a wet state is once dried and then brought into contact with a dampening liquid again, and then pressed against the heated mirror drum surface to perform a high gloss finish.

Further, as another method of providing the glossy expression layer on the ink jet recording sheet of the present invention, while the glossy expression layer coating applied on the ink receiving layer is in a wet state or a semi-dry state, the support surface is applied to the support surface. The substrate is passed between the mirror drum and the press roll while being pressed so as to come into contact with the mirror-finished heated mirror drum to form a coating liquid layer that becomes a glossy expression layer on the ink receiving layer, and then immediately after the mirror finish. A technique according to a casting method comprising a step of peeling the coating liquid layer from the drum is preferred.
However, in this method, the coating liquid layer is instantaneously brought into close contact with the ink receiving layer by press pressure and temperature, and the gloss developing layer is formed as a uniform film without cracks. It is different from the general casting process that performs constrained drying.
Further, it is possible to separately dry the formed glossy expression layer in a drying zone such as a dryer after this step.

  When forming a glossy layer by the cast method, the processing / drying temperature is also important, and if the processing / drying temperature is too high, the film formation proceeds too much and the surface porosity decreases, resulting in a decrease in the ink absorption rate. On the contrary, if the drying temperature is too low, the gloss tends to be poor, and the productivity also decreases.

It is also possible to add a cationic compound to the glossy layer in order to increase the printing density, improve the water resistance, or add various auxiliaries to improve the light resistance and gas resistance.
The coating amount of the glossy layer is preferably 0.2 to 30 g / m ² on a dry solids, more preferably from 0.5 to 20 g / m ^2. When the dry solid content is within this range, the gloss, ink drying property and recording density are excellent.

  In addition, the ink jet recording sheet of the present invention may be formed by coating the ink receiving layer in multiple layers, providing an intermediate layer between the support and the ink receiving layer, or providing a protective layer on the back surface of the support, It is also possible to perform adhesive processing on the back surface of the support, and various known techniques in the field of ink jet recording sheet production can be added.

  The liquid ink for forming a recording image is a recording liquid composed of a colorant, a liquid medium, and other additives. Examples of the colorant include various water-soluble dyes such as direct dyes, acid dyes, and reactive dyes. The liquid medium of the water-based ink includes water alone or a combination of water and a water-soluble organic solvent. Examples of water-soluble organic solvents include monohydric alcohols such as ethyl alcohol and isopropyl alcohol, polyhydric alcohols such as ethylene glycol diethylene glycol, polyethylene glycol and glycerin, triethylene glycol monomethyl ether, triethylin, triethylene glycol monomethyl ether, and triethylene glycol. And lower alkyl ethers of polyhydric alcohols such as monoethyl ether. Examples of the additive include a pH adjuster, a metal sequestering agent, a rust preventive agent, a viscosity adjuster, a surface tension adjuster, a surfactant, and a rust preventive agent.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples. In the examples, “parts” and “%” respectively indicate parts by mass and mass% unless otherwise specified.

(Synthesis of polymer (P) containing ammonium salt unit)
Although the synthesis example of the polymer (P) containing the ammonium salt unit of this invention is shown below, it is not limited to these. The polymer (P) containing an ammonium salt unit of the present invention has an ammonium salt monomer as a starting material, or a combination of an amine monomer and an acid, selection of a copolymerization component, and control of reaction conditions. Can be varied.

<Synthesis Example 1> Synthesis of P-1
In a 1 L three-necked flask, LA-82 (4-methacryloxy-2,2,6,6-tetramethylpiperidine, manufactured by Asahi Denka) 50 g (262 mmol), 36% hydrochloric acid aqueous solution 26.6 g (corresponding to 262 mmol), water 423.4 ml And heated to 60 ° C. After replacing the system with nitrogen, 0.25 g of [2,2′-azobis (2-amidinopropane) hydrochloride] was added, and the reaction was completed while stirring at 60 ° C. for 8 hours. After cooling to room temperature, 500 g of an aqueous solution (concentration 11.9%) containing the target P-1 was obtained.
The Brookfield viscosity of a 10 wt% aqueous solution of P-1 at 25 ° C. was 6.1 mPa · s.

<Synthesis Example 2> Synthesis of P-2
In a 1 L three-necked flask, 45 g (196.6 mmol) of LA-82 (4-methacryloxy-2,2,6,6-tetramethylpiperidine, manufactured by Asahi Denka), 19.9 g of 36% aqueous hydrochloric acid (corresponding to 196.6 mmol) Then, 380.3 ml of water was added, heated to 60 ° C., and the inside of the system was replaced with nitrogen. Then, 0.30 g of [2,2′-azobis (2-amidinopropane) hydrochloride] was added. While maintaining the reaction solution at 60 ° C., 54.8 g (corresponding to 65.4 mmol) of an 8% aqueous solution of acrylamide was dropped over 6 hours, and the mixture was further stirred at 60 ° C. for 2 hours to complete the reaction. The reaction solution was cooled to room temperature to obtain 500 g of an aqueous solution (concentration 11.3%) containing the target P-2.
The Brookfield viscosity at 25 ° C. of a 10 wt% aqueous solution of P-2 was 8.9 mPa · s.

<Synthesis Example 3> Synthesis of P-5
In a 1 L three-necked flask, LA-82 (4-methacryloxy-2,2,6,6-tetramethylpiperidine, manufactured by Asahi Denka) 45 g (196.6 mmol), 36% hydrochloric acid aqueous solution 19.9 g (corresponding to 196.6 mmol), After adding 425.6 ml of water to make a uniform solution, 9.5 g (65.4 mmol) of ACMO (acryloylmorpholine, manufactured by Kojin) was added. The inside of the system was replaced with nitrogen, heated to 60 ° C., added with [2,2′-azobis (2-amidinopropane) hydrochloride] 0.3 g, and stirred for 8 hours while maintaining the reaction solution at 60 ° C. After cooling to room temperature, 500 g of an aqueous solution (concentration 12.3%) containing the target P-5 was obtained.
The Brookfield viscosity at 25 ° C. of a 10 wt% aqueous solution of P-5 was 7.7 mPa · s.

<Synthesis Example 4> Synthesis of P-6
In a 1 L three-necked flask, LA-82 (4-methacryloxy-2,2,6,6-tetramethylpiperidine, manufactured by Asahi Denka) 45 g (196.6 mmol), 36% hydrochloric acid aqueous solution 19.9 g (corresponding to 196.6 mmol), After adding 395.6 ml of water to make a uniform solution, 9.5 g (65.4 mmol) of ACMO (acryloylmorpholine, manufactured by Kojin) was added. After replacing the system with nitrogen, the system was heated to 60 ° C., 15 g of a 2% aqueous solution of [2,2′-azobis (2-amidinopropane) hydrochloride] was added over 1 hour, and the mixture was further stirred at 60 ° C. for 7 hours. To complete the reaction. The reaction solution was cooled to room temperature to obtain 500 g of an aqueous solution (concentration 12.2%) containing the target P-5 ′.
The Brookfield viscosity at 25 ° C. of a 10 wt% aqueous solution of P-6 was 14.3 mPa · s.

<Synthesis Example 5> Synthesis of P-10
In a 500 mL three-necked flask, 50 g (218.3 mmol) of LA-82 (4-methacryloxy-2,2,6,6-tetramethylpiperidine, manufactured by Asahi Denka), 6.4 g (72.8 mmol) of methyl methacrylate, and 300 ml of tetrahydrofuran were added. The system was replaced with nitrogen and heated to 60 ° C., and 0.3 g of 2,2′-azobis (isobutyronitrile) was added. After reacting at 60 ° C. for 8 hours, the mixture was cooled to room temperature and poured into 2 L of hexane with stirring to form white precipitate. The white precipitate was filtered off, washed with a small amount of hexane, and then dried to obtain 50.8 g of a copolymer of LA-82 and methyl methacrylate. Subsequently, 50.8 g of this copolymer was dispersed in 427.1 mL of water, and 22.1 g (corresponding to 218.3 mmol) of 36% hydrochloric acid aqueous solution was added to make a uniform solution, and an aqueous solution containing the target P-10 (concentration) 11.8%) 500 g was obtained.
The Brookfield viscosity of a 10 wt% aqueous solution of P-10 at 25 ° C. was 9.1 mPa · s.
By the way, the molecular weight of the copolymer of LA-82, which is a precursor of P-10, and methyl methacrylate was determined by gel palmtation method (TSK-Gel G1000H XL, TSK-Gel G4000H XL / Tosoh Corporation), developing solvent: Tetrahydrofuran), the styrene equivalent weight average molecular weight was 44,000.

<Synthesis Example 6> Synthesis of P-14
First, N-benzyl-4-methacryloxy-1,2,2,6,6-pentamethylpiperidine chloride was synthesized according to a conventional method. That is, a 500 mL three-necked flask equipped with a cooler and a thermometer and purged with nitrogen was added to 300 ml of dry acetonitrile, LA-87 (4-methacryloxy-1,2,2,6,6-pentamethylpiperidine, manufactured by Asahi Denka ) 45 g (185.2 mmol) and 24.6 g (194.5 mmol) of benzyl chloride were added, and the reaction was performed for 8 and a half hours while refluxing. When the reaction solution was cooled to room temperature, a pale yellow solid was precipitated, which was filtered off and recrystallized from acetonitrile to give the desired N-benzyl-4-methacryloxy-1,2,2,6,6-pentachloride. 67.0 g (yield 98%) of methylpiperidine was obtained.
Subsequently, P-14 (75/25 copolymer of N-benzyl-4-methacryloxy-1,2,2,6,6-pentamethylpiperidine and acrylamide) was synthesized in Synthesis Example 2 (Synthesis of P-2). ) To obtain the same operation. That is, 60.0 g (183.2 mmol) of N-benzyl-4-methacryloxy-1,2,2,6,6-pentamethylpiperidine chloride obtained in the previous synthesis and 388.8 ml of water were obtained in a 1 L three-necked flask. The mixture was heated to 60 ° C. and the system was replaced with nitrogen, and 0.3 g of [2,2′-azobis (2-amidinopropane) hydrochloride] was added. While maintaining the reaction solution at 60 ° C., 51.2 g (corresponding to 61.1 mmol) of an 8% aqueous solution of acrylamide was added dropwise over 6 hours, and the mixture was further stirred at 60 ° C. for 2 hours to complete the reaction. The reaction solution was cooled to room temperature to obtain 500 g of an aqueous solution (concentration 12.8%) containing the target P-14.
Brookfield viscosity at 25 ° C. of a 10 wt% aqueous solution of P-14 was 6.4 mPa · s.

<Synthesis Example 7> Synthesis of P-18
First, the synthesis of 4-acryloxy-2,2,6,6-tetramethylpiperidine was performed according to Peng et. al. , Polym. Bull. 1 , 37 (1981). That is, a 500 mL three-necked flask equipped with a condenser and a thermometer and purged with nitrogen was added to 250 ml of dry methanol, 40 g (254.8 mmol) of 2,2,6,6-tetramethylpiperidin-4-ol, methyl acrylate 23 0.02 g (267.5 mmol) and 20.2 g of 10% methanol solution of magnesium dimethoxide (equivalent to 233.6 mmol) were added, and the reaction was carried out for 8 and a half hours while refluxing. After cooling the reaction solution to room temperature, methanol was distilled off with an evaporator and the residue was recrystallized with acetone / water to obtain 45.5 g of the desired 4-acryloxy-2,2,6,6-tetramethylpiperidine ( Yield 83%) was obtained.
Subsequently, P-18 (75/25 copolymer of 4-acryloxy-2,2,6,6-tetramethylpiperidine and acryloylmorpholine) was subjected to the same operation as in Synthesis Example 3 (synthesis of P-5). Obtained by doing. That is, 4-acryloxy-2,2,6,6-tetramethylpiperidine (42.2 g, 196.6 mmol), 36% hydrochloric acid aqueous solution (19.9 g, equivalent to 196.6 mmol), and water (428.4 ml) were added, and uniform. After preparing the solution, 9.5 g (65.4 mmol) of ACMO (acryloylmorpholine, manufactured by Kojin) was added. The inside of the system was replaced with nitrogen, heated to 60 ° C., added with [2,2′-azobis (2-amidinopropane) hydrochloride] 0.3 g, and stirred for 8 hours while maintaining the reaction solution at 60 ° C. After cooling to room temperature, 500 g of an aqueous solution (concentration: 11.8%) containing the target P-18 was obtained.
Brookfield viscosity at 25 ° C. of a 10 wt% aqueous solution of P-18 was 7.2 mPa · s.

(Preparation of inkjet recording sheet and performance evaluation)
Preparation of inkjet recording sheet:
The ink jet recording sheet containing the polymer (P) containing the ammonium salt of the present invention was prepared as in the following examples, but the method is not limited, and a known publicly used technique or those may be arranged. Can also be produced.
Performance evaluation of the prepared inkjet recording sheet:
An ink-jet recording sheet produced in the examples and comparative examples was subjected to an ISO-400 image (“high-definition color digital standard image data ISO / JIS-SCID”, p13, image) using an Epson inkjet printer PM-950C. Name: Portrait, issued by the Japan Planning Association), solid printing with an output setting of Bk = 100%, and solid printing with a composite black optical density of 1.0. [Optical density], [Image quality], [Heat and humidity resistance] and [Water resistance] were evaluated by the following methods.

[Optical density]
The solid-printed image with an output setting of Bk = 100% was measured with a Macbeth reflection densitometer RD-914, and the optical density was compared and evaluated.
(Evaluation criteria)
The higher the optical density, the more preferable. If OD> 2.25 (OD> 1.85 in the case of mat type), it is advantageously used practically.
〔image quality〕
The image quality of the obtained ISO-400 image was evaluated by visual observation.
(Evaluation criteria)
◎: Image quality is very good ○: Image quality is good and has no practical problem △: Image quality is inferior and practically problematic ×: Image quality is inferior

[Heat and humidity resistance]
The obtained ISO-400 image, a solid print image with a Bk = 100% output setting, and a solid black print image of composite black were left for 24 hours after printing, and then placed in a constant temperature and humidity chamber at 40 ° C. and 90% relative humidity for 24 hours. Stored and visually observed and evaluated the level of heat and humidity resistance.
(Evaluation criteria)
A: Occurrence of blurring and discoloration over time was hardly observed, and the print quality before processing was maintained. ○: A slight blurring and discoloration over time were observed, but at a level where there was no problem in practical use. Δ: aging blurring and discoloration were observed, and there was a practically problematic level. X: aging blurring was remarkably observed, and discoloration was also remarkable, which was a practically problematic level.

〔water resistant〕
The resulting ISO-400 image, solid print image with Bk = 100% output setting, and composite black solid print image are left for 24 hours after printing, then ISO-400 image, solid print with output setting of Bk = 100% Distilled water was dropped drop by drop on each of the image and the composite black solid print image, the droplets were air-dried, and the blisters were visually observed to evaluate the level of water resistance.
(Evaluation criteria)
◎: Image distortion and ink blur were not observed, and the print quality before processing was maintained. ○: Slight image distortion and ink blur were observed, but there was no practical problem. : Clearly disturbed image and ink blurring were at a level that was problematic in practical use. ×: Disturbance of image and ink blurring were remarkable and at a practically problematic level.

Example 1
(Preparation of coating liquid A for ink receiving layer)
Gas phase method silica (trade name: Aerosil 300, average particle size of primary particles 7 nm, specific surface area 300 m ² / g by BET method, manufactured by Nippon Aerosil Kogyo Co., Ltd.), P- prepared in Synthesis Example 1 150 parts of 10% aqueous solution of 1 (4-methacryloxy-2,2,6,6-tetramethylpiperidine hydrochloride homopolymer, Brookfield viscosity of 10% aqueous solution = 6.1 mPa · s) and 750 ion-exchanged water After adding a part and disperse | distributing with a stirring apparatus, it processed using the wet super atomizer nanomizer. Next, 360 parts of 5% aqueous solution of polyvinyl alcohol (trade name: PVA-145, manufactured by Kuraray Co., Ltd., saponification degree 99%, average polymerization degree 4,500) and a small amount of antifoaming agent, dispersant and water were added. An ink receiving layer coating solution A having a solid content concentration of 8% was obtained.

(Adjustment of coating liquid B for undercoat layer)
500 parts of a 20% dispersion of a wet process synthetic amorphous silica (trade name: Silojet 703A, manufactured by Grace Devison), 400 parts of a 5% aqueous solution of polyvinyl alcohol (trade name: PVA-145, manufactured by Kuraray Co., Ltd.) A small amount of an antifoaming agent, a dispersant and water were added to obtain an undercoat layer coating solution B having a solid concentration of 15%.

(Creation of inkjet recording sheet)
Solid undercoat layer coating liquid B on laminate coated paper (commercially coated paper (trade name: OK coated paper, 127.9 g / m 2, Oji Paper Co., Ltd.) with 15 μm of polyethylene laminated) Apply and dry with a Mayer bar so that it becomes 20 g / m @ 2 in minutes, and then provide an undercoat layer. Then, after applying water, apply and dry the coating liquid A for ink-receiving layer with a Mayer bar so that the solid content becomes 7 g / m @ 2. Thus, an ink receiving layer was provided to prepare an ink jet recording sheet.

Examples 2 to 21
In Example 1, instead of the homopolymer of P-1: 4-methacryloxy-2,2,6,6-tetramethylpiperidine hydrochloride (Brookfield viscosity of a 10% aqueous solution = 6.1 mPa · s), An ink jet recording sheet was prepared in the same manner as in Example 1 except that the compounds shown in Table 1 were used.

  In addition, the polymer (P) containing an ammonium salt unit in the examples selects various amine monomers, various copolymerization components, and various acids according to Synthesis Examples 1 to 5 described above, and reaction conditions. It adjusted and adjusted suitably.

LA-82: 4-Methacryloxy-2,2,6,6-tetramethylpiperidine
LA-87: 4-Methacryloxy-1,2,2,6,6-pentamethylpiperidine
MPMP-EO adduct: 4-methacryloxyethoxy-1,2,2,6,6-pentamethylpiperidine
ATMP: 4-acryloxy-2,2,6,6-tetramethylpiperidine
AAM: Acrylamide
MAAM: Methacrylamide
ACMO: Acryloylmorpholine
NVP: N-vinylpyrrolidone
MMA: Methyl methacrylate
MsOH: Methanesulfonic acid
BnCl: benzyl chloride

Example 22
In Example 1, the homopolymer of P-1 (4-methacryloxy-2,2,6,6-tetramethylpiperidine hydrochloride prepared in Synthesis Example 1 above, Brookfield viscosity of 10% aqueous solution = 6.1 mPa -Instead of 150 parts of 10% aqueous solution of s), P-2 (4-methacryloxy-2,2,6,6-tetramethylpiperidine hydrochloride-acrylamide copolymer prepared in Synthesis Example 2 above, molar ratio = 75/25, 10% aqueous solution Brookfield viscosity = 8.9 mPa · s) 75% 10% aqueous solution and N-vinylacrylamidine hydrochloride-acrylamide copolymer (molar ratio 2: 1, molecular weight about 20,000) An ink jet recording sheet was prepared in the same manner as in Example 1 except that 25 parts of the 30% aqueous solution was used.

Example 23
(Preparation of silica fine particle dispersion)
Distilled water was added to a sodium silicate solution having a SiO ₂ concentration of 30% by mass and a SiO ₂ / Na ₂ O molar ratio of 3.1 (manufactured by Tokuyama Corp., No. 3 sodium silicate) to obtain a SiO ₂ concentration of 4.0% by mass. After preparing a dilute sodium silicate aqueous solution, an active silicic acid aqueous solution was prepared through a column packed with a hydrogen-type cation exchange resin (manufactured by Mitsubishi Chemical Corporation, Diaion SK-1BH). A 5 liter glass reaction vessel equipped with a reflux, stirrer, and thermometer was charged with 500 g of distilled water, heated to 100 ° C., and kept at 100 ° C., the active silicic acid aqueous solution prepared earlier was 1.5 g / min. 450 g was added at a rate of 1 to prepare a seed solution. The average secondary particle diameter of the seed particle aggregate in the seed solution was 184 nm. Next, after stabilizing by adding 0.9 g of 28% ammonia aqueous solution, 550 g of active silicic acid aqueous solution was further added at a rate of 1.5 g / min at 100 ° C. After completion of the addition, the mixture was heated to reflux at 100 ° C. for 9 hours and then concentrated to obtain a 10% by mass silica fine particle dispersion. The silica particles had an average primary particle size of 11 nm, an average secondary particle size of 130 nm, and a specific surface area of 257 m ² / g.
(Preparation of coating liquid C for ink receiving layer)
To 1000 parts of the 10% by mass silica fine particle dispersion obtained earlier, P-2 (4-methacryloxy-2,2,6,6-tetramethylpiperidine hydrochloride-acrylamide copolymer prepared in Synthesis Example 2 above, After adding 150 parts of a 10% aqueous solution having a molar ratio of 75/25, Brookfield viscosity of 10% aqueous solution = 8.9 mPa · s) and dispersing with a stirrer, the mixture was processed using a wet micronizer Nanomizer. Next, 360 parts of 5% aqueous solution of polyvinyl alcohol (trade name: PVA-145, manufactured by Kuraray Co., Ltd., saponification degree 99%, average polymerization degree 4,500) and a small amount of antifoaming agent, dispersant and water were added. An ink receiving layer coating solution C having a solid content concentration of 8% was obtained.

(Creation of inkjet recording sheet)
Coating liquid B for undercoat layer on laminate coated paper (commercially coated paper (trade name: OK coated paper, 127.9 g / m ² , Oji Paper Co., Ltd.) with 15 μm of polyethylene laminated) Apply and dry with a Mayer bar so that the solid content is 20 g / m ^2, and then provide an undercoat layer. Then, after applying water, the ink receiving layer coating solution D is applied to the Mayer bar so that the solid content is 5 g / m ^2. The ink receiving layer was provided by coating and drying to prepare an ink jet recording sheet.

Example 24
(Creation of inkjet recording sheet)
Prepared in Synthesis Example 2 above on laminated coated paper (commercially-coated paper (trade name: OK coated paper, 127.9 g / m ² , Oji Paper Co., Ltd.) with 15 μm of polyethylene laminated) P-2 (4-methacryloxy-2,2,6,6-tetramethylpiperidine hydrochloride-acrylamide copolymer, molar ratio = 75/25, Brookfield viscosity of 10% aqueous solution = 8.9 mPa · s) The ink receiving layer coating liquid A was applied and dried with a Mayer bar so that the solid content was 20 g / m ^2, and an ink receiving layer was provided to prepare an ink jet recording sheet.

Comparative Examples 1-2
In Example 1, instead of the homopolymer of P-1: 4-methacryloxy-2,2,6,6-tetramethylpiperidine hydrochloride (Brookfield viscosity of a 10% aqueous solution = 6.1 mPa · s), An ink jet recording sheet was prepared in the same manner as in Example 1 except that the following ammonium salt polymer was used.

Comparative Example 1
PAS-J-81 (copolymer of dimethyldiallylammonium chloride and acrylamide, manufactured by Nittobo Co., Ltd.)

Comparative Example 2
Sumilace resin SR-1001 (copolymer of diallylammonium chloride and acrylamide, manufactured by Sumitomo Chemical Co., Ltd.)

  Table 2 summarizes the performance of the ink jet recording sheet produced as described above.

  As is apparent from Table 2, when the ink jet recording sheet is prepared using the polymer (P) of the present invention containing an ammonium salt unit having a specific structure (Examples 1 to 24), the stability of the ink receiving layer coating material is improved. Therefore, there is no difficulty in producing an ink jet recording sheet, the recording density is high, the recorded image is clear, and the water / moisture resistance is excellent. On the other hand, when the ammonium salt polymer of Comparative Example 1 is used, inkjet recording sheets can be easily produced, but there is room for improvement in the water resistance and moisture resistance of recorded images. In addition, when the ammonium salt polymer of Comparative Example 2 is used, the stability of the ink-receiving layer coating material is remarkably reduced, making the ink jet recording sheet relatively difficult, and lowering the recording density and the print quality. However, the water resistance and moisture resistance of the recorded image are extremely inferior.

Example 25
(Preparation of coating liquid D for ink receiving layer)
Gas phase method silica (trade name: Aerosil 300, manufactured by Nippon Aerosil Industrial Co., Ltd.) 100 parts, N-vinylacrylamidine hydrochloride-acrylamide copolymer (molar ratio 2: 1, molecular weight about 20,000) 30% After adding 50 parts of aqueous solution and 750 parts of ion-exchanged water and dispersing with a stirrer, the mixture was processed using a wet ultrafine atomizer Nanomizer. Next, 360 parts of 5% aqueous solution of polyvinyl alcohol (trade name: PVA-145, manufactured by Kuraray Co., Ltd., saponification degree 99%, average polymerization degree 4,500) and a small amount of antifoaming agent, dispersant and water were added. An ink receiving layer coating liquid D having a solid content concentration of 8% was obtained.

(Creation of inkjet recording sheet)
Coating liquid B for undercoat layer on laminate coated paper (commercially coated paper (trade name: OK coated paper, 127.9 g / m ² , made by Oji Paper Co., Ltd.) with 15 μm of polyethylene laminated) P-1 (4-methacryloxy-2,2,6,6-tetramethyl) prepared in Synthesis Example 1 was prepared by applying and drying with a Mayer bar so that the solid content was 20 g / m ^2. A 1% aqueous solution of a piperidine hydrochloride homopolymer, a 10% aqueous solution of Brookfield viscosity = 6.1 mPa · s) is applied so that the solid content is 0.5 g / m ^2, and an ink receiving layer is formed thereon. The coating liquid D was applied and dried with a Mayer bar so that the solid content was 7 g / m ² , an ink receiving layer was provided, and an ink jet recording sheet was prepared.

Examples 26-33
In Example 25, instead of P-1 (4-methacryloxy-2,2,6,6-tetramethylpiperidine hydrochloride homopolymer, Brookfield viscosity of 10% aqueous solution = 6.1 mPa · s), An ink jet recording sheet was prepared in the same manner as in Example 25 except that the compounds shown in Table 3 were used.

Comparative Examples 3-5
In Example 25, instead of a homopolymer of P-1: 4-methacryloxy-2,2,6,6-tetramethylpiperidine hydrochloride (Brookfield viscosity of a 10% aqueous solution = 6.1 mPa · s), An ink jet recording sheet was prepared in the same manner as in Example 25 except that the following ammonium salt polymer was used.

Comparative Example 3
PAS-J-81 (copolymer of dimethyldiallylammonium chloride and acrylamide, manufactured by Nittobo Co., Ltd.)

Comparative Example 4
Sumilace resin SR-1001 (copolymer of diallylammonium chloride and acrylamide, manufactured by Sumitomo Chemical Co., Ltd.)

Comparative Example 5
In Example 25, without using a homopolymer of P-1: 4-methacryloxy-2,2,6,6-tetramethylpiperidine hydrochloride (Brookfield viscosity of 10% aqueous solution = 6.1 mPa · s) In the same manner as in Example 25, an inkjet recording sheet was prepared.

  The performance of the inkjet recording sheet produced as described above is summarized in Table 4.

  As is apparent from Table 4, when the ink jet recording sheet is produced using the polymer (P) of the present invention containing an ammonium salt unit having a specific structure (Examples 25 to 33), the recording density is also high and obtained. The recorded image is clear and has excellent water and moisture resistance. On the other hand, even if the ammonium salt polymers of Comparative Examples 3 and 4 are used, the water resistance and moisture resistance of the recorded image cannot be improved. In Comparative Example 5, recording can be performed at a sufficiently high concentration without using the polymer (P) of the present invention containing an ammonium salt unit having a specific structure at all. However, the water resistance and moisture resistance of the recorded image are still not good. Is complete.

Example 34
(Preparation of coating liquid E for undercoat layer)
Wet process synthetic amorphous silica (trade name: Fine Seal X-30, manufactured by Tokuyama Co., Ltd.) 100 parts, silicon-modified polyvinyl alcohol (trade name: R-1130, manufactured by Kuraray Co., Ltd., degree of saponification 98.5) %, Average polymerization degree 3,000) 10% aqueous solution 200 parts and a small amount of antifoaming agent, dispersant and water, solid content concentration 15% undercoat layer coating solution E was obtained.

(Preparation of coating liquid F for ink receiving layer)
Gas phase method silica (trade name: Aerosil 300, manufactured by Nippon Aerosil Industrial Co., Ltd.) 100 parts, P-1 (4-methacryloxy-2,2,6,6-tetramethylpiperidine) prepared in Synthesis Example 1 Hydrochloric acid homopolymer, Brookfield viscosity of 10% aqueous solution 300 parts of 10% aqueous solution and 600 parts of ion-exchanged water were added and dispersed with a stirrer. Processed. Next, 200 parts of a 10% aqueous solution of polyvinyl alcohol (trade name: PVA-117, manufactured by Kuraray Co., Ltd., degree of saponification 98.5%, average degree of polymerization 1,700) and a small amount of antifoaming agent, dispersing agent and water Was added to obtain an ink-receiving layer coating solution f having a solid concentration of 10%.

(Preparation of casting coating solution G)
Solid content concentration consisting of 95 parts of a styrene-2-ethylhexyl acrylate copolymer and colloidal silica having a glass transition point of 75 ° C. (copolymer and colloidal silica are 20:80 by weight) and 5 parts of potassium stearyl phosphate. A 10% cast coating solution G was obtained.

(Creation of inkjet recording sheet)
Coated and dried on a high-quality paper of 200 g / m ² by Mayer bar so as the undercoat layer coating liquid E becomes 10 g / m ² on a solids subbing layer, and then the solid coating liquid F for the ink receiving layer The ink receiving layer was provided by applying and drying with a Mayer bar so that the amount was 5 g / m ² per minute. Furthermore, after applying the coating liquid G for cast coating with a Mayer bar, immediately after pressing and drying on a mirror drum having a surface temperature of 85 ° C., a cast coating layer was formed to prepare an ink jet recording sheet. . The coating amount of the cast coating layer at this time was 2 g / m ² in terms of solid content.

Examples 35-42
In Example 34, the homopolymer of P-1 (4-methacryloxy-2,2,6,6-tetramethylpiperidine hydrochloride prepared in Synthesis Example 1 above, Brookfield viscosity of 10% aqueous solution = 6.1 mPa An ink jet recording sheet was prepared in the same manner as in Example 25 except that the compounds shown in Table 5 were used instead of s).

Comparative Examples 6-7
In Example 34, instead of P-1: Homopolymer of 4-methacryloxy-2,2,6,6-tetramethylpiperidine hydrochloride (Brookfield viscosity of 10% aqueous solution = 6.1 mPa · s), An ink jet recording sheet was prepared in the same manner as in Example 34 except that the following ammonium salt polymer was used.

Comparative Example 6
PAS-J-81 (copolymer of dimethyldiallylammonium chloride and acrylamide, manufactured by Nittobo Co., Ltd.)

Comparative Example 7
Sumilace resin SR-1001 (copolymer of diallylammonium chloride and acrylamide, manufactured by Sumitomo Chemical Co., Ltd.)

  Table 6 summarizes the performance of the ink jet recording sheet produced as described above.

  As is apparent from Table 6, when the ink jet recording sheet is prepared using the polymer (P) of the present invention containing an ammonium salt unit having a specific structure (Examples 34 to 42), the stability of the ink receiving layer coating material is improved. Therefore, there is no difficulty in producing an ink jet recording sheet, the recording density is high, the recorded image is clear, and the water / moisture resistance is excellent. On the other hand, when the ammonium salt polymer of Comparative Example 6 is used, inkjet recording sheets can be easily produced, but there is room for improvement in water resistance and moisture resistance of recorded images. In addition, when the ammonium salt polymer of Comparative Example 7 is used, the stability of the ink-receiving layer paint is inferior, and the ammonium salt is eluted from the ink-receiving layer during the casting process. In addition to the difficulty in producing the sheet for printing, the recording density and the printing quality are lowered, and the water resistance and moisture resistance of the recorded image are remarkably impaired.

Example 43
(Preparation of coating liquid H for ink receiving layer)
Wet process synthetic amorphous silica (trade name: Fine Seal X-60, manufactured by Tokuyama Corporation) 100 parts, silicon-modified polyvinyl alcohol (trade name: R-1130, manufactured by Kuraray Co., Ltd., degree of saponification 98.5) 300 parts of a 10% aqueous solution with an average degree of polymerization of 3,000), a homopolymer of P-1 (4-methacryloxy-2,2,6,6-tetramethylpiperidine hydrochloride prepared in Synthesis Example 1; 400 parts of a 10% aqueous solution having a 10% aqueous solution Brookfield viscosity = 6.1 mPa · s) and a small amount of an antifoaming agent, a dispersing agent, and water, and a solid content concentration of 20% of an ink receiving layer coating liquid H were obtained. .

(Creation of inkjet recording sheet)
After coating the ink receiving layer coating solution H to fine paper of 200 g / m ² by Mayer bar so that the 10 g / m ² in solid content was dried, the ink jet recording sheet having an ink-receiving layer of the mat type It was created.

Examples 44-51
In Example 43, instead of P-1 (4-methacryloxy-2,2,6,6-tetramethylpiperidine hydrochloride homopolymer, Brookfield viscosity of 10% aqueous solution = 6.1 mPa · s), An ink jet recording sheet was prepared in the same manner as in Example 43 except that the compounds shown in Table 7 were used.

Comparative Examples 8-9
In Example 43, instead of P-1: Homopolymer of 4-methacryloxy-2,2,6,6-tetramethylpiperidine hydrochloride (Brookfield viscosity of 10% aqueous solution = 6.1 mPa · s), An ink jet recording sheet was prepared in the same manner as in Example 43 except that the following ammonium salt polymer was used.

Comparative Example 8
PAS-J-81 (copolymer of dimethyldiallylammonium chloride and acrylamide, manufactured by Nittobo Co., Ltd.)

Comparative Example 9
Sumilace resin SR-1001 (copolymer of diallylammonium chloride and acrylamide, manufactured by Sumitomo Chemical Co., Ltd.)

Comparative Examples 10-11
In the same manner as in Example 49, mat type ink jet recording sheets were prepared as in Comparative Examples 10 and 11 below. However, the ink jet recording sheets prepared in the following Comparative Examples 10 and 11 do not include the polymer having the specific ammonium salt unit of the present invention, but include an amine polymer corresponding to the matrix. .
In addition, since most of the amine polymers corresponding to the matrix of the polymer having the specific ammonium salt unit of the present invention are hardly soluble to insoluble in water, it is not an aqueous solution but an aqueous emulsion or a solution dissolved in an organic solvent. It was used for preparation of the sheet | seat for inkjet recording in the form.

Comparative Example 10
(Preparation of Emulsion E-1)
Emulsion E-1 (copolymer emulsion of 4-methacryloxy-2,2,6,6-tetramethylpiperidine and acryloylmorpholine, copolymerization ratio = 75/25) was obtained by emulsion polymerization in water by a conventional method. . That is, 230.6 g of water and 3.4 g of emulsifier (manufactured by Kao: Emulgen 950) are added to a 500 ml three-necked flask to dissolve the emulsifier. Thereafter, 42.2 g of 4-methacryloxy-2,2,6,6-tetramethylpiperidine and 14.1 g of methyl methacrylate were added to the flask and heated to 50 ° C. with sufficient stirring. Next, the system was replaced with nitrogen, and 9.8 g of 4% potassium persulfate aqueous solution was added, followed by reaction with stirring at 50 ° C. for 20 hours to obtain 300 g of the target polymer emulsion E-1 (concentration 20%). It was.

(Preparation of coating solution I for ink receiving layer)
Wet process synthetic amorphous silica (trade name: Fine Seal X-60, manufactured by Tokuyama Corporation) 100 parts, silicon-modified polyvinyl alcohol (trade name: R-1130, manufactured by Kuraray Co., Ltd., degree of saponification 98.5) %, Average polymerization degree 3,000) 10% aqueous solution, 200 parts of 20% aqueous solution of emulsion E-1 synthesized as described above, water, and a small amount of antifoaming agent and dispersing agent, solid content concentration 20% of the ink receiving layer coating liquid H was obtained.

(Creation of inkjet recording sheet)
After coating the ink receiving layer coating solution I in fine paper of 200 g / m ² by Mayer bar so that the 10 g / m ² in solid content was dried, the ink jet recording sheet having an ink-receiving layer of the mat type It was created.

Comparative Example 11
(Preparation of coating liquid J for ink receiving layer)
A synthetic solution of 4-methacryloxy-2,2,6,6-tetramethylpiperidine and acryloylmorpholine (copolymerization ratio = 75/25) synthesized by a conventional method was mixed with ethyl acetate / toluene. Silica-copolymer composite pigment (silica / copolymer = 100 parts / 40 parts) 100 obtained by spraying and drying on crystalline silica (trade name: Fine Seal X-60, manufactured by Tokuyama Corporation) Parts, 214 parts of a 10% aqueous solution of silicon-modified polyvinyl alcohol (trade name: R-1130, manufactured by Kuraray Co., Ltd., saponification degree 98.5%, average polymerization degree 3,000), water, and a small amount of antifoaming agent An ink-receiving layer coating liquid J having a solid content concentration of 20% was prepared.

(Creation of inkjet recording sheet)
After coating the ink receiving layer coating solution J in fine paper of 200 g / m ² by Mayer bar so that the 10 g / m ² in solid content was dried, the ink jet recording sheet having an ink-receiving layer of the mat type It was created.

  Table 8 summarizes the performance of the ink jet recording sheet prepared as described above.

  As is apparent from Table 8, when the ink jet recording sheet is prepared using the polymer (P) of the present invention containing an ammonium salt unit having a specific structure (Examples 43 to 51), the stability of the ink receiving layer coating material is improved. Therefore, there is no difficulty in producing an ink jet recording sheet, the recording density is high, the recorded image is clear, and the water / moisture resistance is excellent. On the other hand, when the ammonium salt polymer of Comparative Example 8 is used, the ink jet recording sheet can be easily produced, but there is room for improvement in the water resistance and moisture resistance of the recorded image. In addition, when the ammonium salt polymer of Comparative Example 9 is used, the ink-receiving layer coating material has a relatively high viscosity and exhibits a slightly strong thixotropic property, so that it is relatively difficult to produce an inkjet recording sheet. Both the print quality and the water resistance and moisture resistance of the recorded image are significantly impaired. Further, since Comparative Examples 10 and 11 do not contain a cationic compound, both the recording density and the printing quality are low, and the water resistance and moisture resistance of the recorded image cannot be exhibited.

The ink jet recording sheet is particularly suitable for an ink jet recording sheet that has high image quality, high gloss, excellent ink absorbability, and excellent suppression of blurring of recorded images over time in a high temperature and high humidity environment.

Claims (14)

An ink jet recording sheet comprising a polymer having an ammonium salt unit represented by the following general formula (1).

[Wherein R1 represents a hydrogen atom or a methyl group, R2 represents a divalent organic group, and R3 and R4 are each independently selected from a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, and a benzyl group. Y- represents an anion residue, and n represents an integer of 0-8. ] In the inkjet recording sheet comprising the polymer having the ammonium salt unit, the polymer having the ammonium salt unit is an ammonium salt unit represented by the general formula (1), and the following general formulas (2) to (4): 2. The ink jet recording sheet according to claim 1, which is a copolymer of at least one selected from units represented by

[Wherein, R5 represents a hydrogen atom or a methyl group, and R6 represents one selected from a hydrogen atom or a lower alkyl group having 1 to 8 carbon atoms. ]

[Wherein R7 represents a hydrogen atom or a methyl group, and R8 and R9 each independently represent a hydrogen atom or a lower alkyl group having 1 to 8 carbon atoms, or R8 and R9] Are bonded to each other to form a nitrogen-containing five-membered ring structure or a nitrogen-containing six-membered ring structure together with the nitrogen atoms to which they are bonded. ]

[Wherein R10 represents a hydrogen atom or a methyl group, and Z is selected from a hydrogen atom, a hydroxyl group, a phenyl group, an acetoxy group, a formamide group, an acetamide group, a carbamate group, a 2-pyrrolidonyl group, or a cyano group. Represents a kind. ] The inkjet recording sheet comprising the polymer having an ammonium salt unit, wherein the polymer having the ammonium salt unit has a weight average molecular weight of 1,000 or more and 1,000,000 or less. Inkjet recording sheet. In the inkjet recording sheet comprising the polymer having an ammonium salt unit, the inkjet recording sheet has at least one or more inorganic fine particles and an aqueous polymer binder on the support surface, and the ammonium salt. The ink jet recording sheet according to any one of claims 1 to 3, further comprising at least one ink-receiving layer containing a polymer having a unit. The inkjet recording sheet according to claim 4, wherein at least one of the inorganic fine particles has an average primary particle size of 30 nm or less. 6. The ink jet recording sheet according to claim 4, wherein at least one of the inorganic fine particles is vapor phase silica. The inkjet recording sheet according to claim 4 or 5, wherein the inorganic fine particles are wet-process fine silica produced by condensing activated silicic acid. At least one of the inorganic fine particles is a cationic composite fine particle of silica having an average primary particle size of 30 nm or less and a polymer having an ammonium salt unit represented by the following general formula (1). The inkjet recording sheet according to claim 4, wherein

[Wherein R1 represents a hydrogen atom or a methyl group, R2 represents a divalent organic group, and R3 and R4 are each independently selected from a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, and a benzyl group. Y- represents an anion residue, and n represents an integer of 0-8. ] At least one of the inorganic fine particles is represented by silica having an average primary particle size of 30 nm or less, an ammonium salt unit represented by the general formula (1), and the following general formulas (2) to (4). The inkjet recording sheet according to claim 4, which is a cationic composite fine particle with at least one kind of copolymer selected from the above units.

[Wherein, R5 represents a hydrogen atom or a methyl group, and R6 represents one selected from a hydrogen atom or a lower alkyl group having 1 to 8 carbon atoms. ]

[Wherein R7 represents a hydrogen atom or a methyl group, and R8 and R9 each independently represent a hydrogen atom or a lower alkyl group having 1 to 8 carbon atoms, or R8 and R9] Are bonded to each other to form a nitrogen-containing five-membered ring structure or a nitrogen-containing six-membered ring structure together with the nitrogen atoms to which they are bonded. ]

[Wherein R10 represents a hydrogen atom or a methyl group, and Z is selected from a hydrogen atom, a hydroxyl group, a phenyl group, an acetoxy group, a formamide group, an acetamide group, a carbamate group, a 2-pyrrolidonyl group, or a cyano group. Represents a kind. ] The ink jet recording sheet according to claim 1, wherein the support is paper. The inkjet recording sheet according to any one of claims 1 to 9, wherein the support is a water-resistant support. 12. The ink jet recording sheet according to claim 11, wherein the water resistant support is a support having both sides of paper coated with a polyolefin resin. The ink jet recording sheet according to claim 1, wherein the ink jet recording sheet has an ink receiving layer subjected to a cast treatment. The inkjet recording sheet according to any one of claims 1 to 13, wherein the inkjet recording sheet has a glossy expression layer formed by a casting process above the ink receiving layer.