JP3581023B2 - Ink jet recording sheet - Google Patents

Description

【００５４】

【００５５】
【表１】

【００５６】
更に比較例として、本発明１の下層を上層に、上層を下層に逆転して塗布したものを比較例７とした。これらの１０種類の記録シートについて、インクジェットプリンター（エプソン社製のＭＪ９３０） を用いて、インク吸収容量、乾燥性、光沢度を下記の方法で試験した。結果を表２に示す。
【００５７】
＜インク吸収容量＞
Ｙ、Ｍ、Ｃ、Ｋの各インクの最大インク量の１００％吐出時のインクの溢れの状態を目視で観察し、下記の基準で評価した。
◎：印字直後に全く溢れない。
○：印字直後に僅かに溢れているが、約１０秒後以内に吸収する。
△：印字直後に溢れており、約２０秒後以内に吸収する。
×：印字直後に溢れており、吸収するのに３０秒以上かかる。
【００５８】
＜乾燥性＞
上記条件で印字後、一定時間経過後、普通紙を重ねて放置し、インクが普通紙に転写しなくなるまでの時間を測定し以下の基準で評価した。
◎：２分以内
○：２〜４分
△：４〜６分
×：６分以上
【００５９】
＜光沢度＞
鏡面光沢度測定方法（ＪＩＳ−Ｚ８７４１）による６０度鏡面光沢を光沢計（日本電色工業（株）製ＶＧＳ−１Ｄ）を用いて測定した。
【００６０】
【表２】

【００６１】
上記結果より、本発明の記録シートは、インク吸収容量が多く、かつ乾燥性及び光沢性に優れていることが分かる。
【００６２】
実施例２
実施例１の本発明２の記録シートに用いた気相法シリカＡに代えて、平均一次粒子径が７ｎｍの気相法シリカ、もしくは平均一次粒子径が２０ｎｍの気相法シリカを用いた以外は本発明２の記録シートと同様にして、本発明の２種類の記録シートを作成した。実施例１と同様に試験した結果、前記２種類の記録シートはいずれも本発明２の記録シートと同様な結果が得られた。
【００６３】
実施例３
実施例１の本発明２の記録シートに用いたゼラチンに代えて、
（１）ポリビニルピロリドンを５ｇ／ｍ^２
（２）カルボキシメチルセルロースを５ｇ／ｍ^２
（３）ゼラチン２．５ｇ／ｍ^２とポリビニルピロリドン２．５ｇ／ｍ^２
（４）ゼラチン２．５ｇ／ｍ^２とカルボキシメチルセルロース２．５ｇ／ｍ^２
を、それぞれ用いる以外は本発明２の記録シートと同様にして、本発明の４種類の記録シートを作成した。実施例１と同様に試験した結果、前記４種類の記録シートはいずれも本発明２の記録シートと同様な結果が得られた。
【００６４】
実施例４
実施例１に従って、表３に示すような本発明の記録シートを作成した。
【００６５】
【表３】

【００６６】
上記記載の方法で作成した記録シートをインク量の多いインクジェットプロッター（エンキャド社製のＮｏｖａｊｅｔ ＰＲＯ、ＧＡインク）を用いて、Ｙ、Ｍ、Ｃ、Ｋの各インクの最大インク量の９０％吐出で印字し、インク吸収容量、乾燥性及び光沢性を実施例１と同様な方法で評価した。その結果を表４に示す。
【００６７】
【表４】

【００６８】
上記結果から、（Ａ×２）＋（Ｂ×８）≧４０を満足する層構成にすることによって、更にインク量の多いプロッターに充分適用できることが分かる。特に（Ａ×２）＋（Ｂ×８）≧５０を満足させることによって、更に大きな効果が得られる。
【００６９】
実施例５
実施例４の本発明４〜９の記録シートにおいて、下層にコハク酸をゼラチン量に対して１０重量％、あるいはリンゴ酸を５重量％添加する以外同様にして本発明１０〜２１の記録シートを作成した。これらの記録シートをインク量の多いインクジェットプロッター（エンキャド社製のＮｏｖａｊｅｔ ＰＲＯ、ＧＡインク）を用いて、Ｙ、Ｍ、Ｃ、Ｋの各インクの最大インク量の１００％吐出で印字し、インク吸収容量、乾燥性及び光沢性を実施例１と同様な方法で評価した。その結果を表５に示す。
【００７０】
【表５】

【００７１】
上記結果から、コハク酸、リンゴ酸のような炭素数４以下の脂肪族カルボン酸を下層の水溶性ポリマー層に含有させることによって、インク吐出量を更に増やしても、十分に対応できることが分かる。
【００７２】
実施例６
実施例４の本発明９の記録シートの上層に、架橋剤としてホウ酸あるいはグリオキザールをポリビニルアルコールに対して１重量％添加した以外、本発明９と同様にして本発明の記録シート２２、２３を作成した。実施例４と同様の方法でインク吸収容量、乾燥性及び光沢性を評価した。その結果、インク吸収容量及び乾燥性は、本発明２２、２３の記録シートは本発明９と同程度であり、光沢性は、更に５％上昇した。この光沢の上昇は、上層に硬膜剤を含有させることによって、インク吸収時に下層が膨潤するのに伴う上層の歪みによる微小な亀裂の発生が防止できたためである。
【００７３】
【発明の効果】
本発明のインクジェット記録シートによれば、インク吸収容量、乾燥性及び光沢度を同時に満足することができる。特にインク量の多い高速プロッターに好適に用いられる。また下層に水溶性ポリマーとともに特定のカルボン酸を含有させることによって、更にインク吸収容量及び乾燥性が向上する。また、上層に気相法シリカとともにバインダーとその架橋剤を含有させることによって、微小な亀裂を防止し、光沢を更に向上させることができる。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an ink jet recording sheet, and particularly to an ink jet recording sheet excellent in ink absorption capacity, dryness after printing, and glossiness.
[0002]
[Prior art]
As a recording sheet used in the ink jet recording system, a porous ink made of a water-soluble binder such as polyvinyl alcohol is coated with a pigment such as amorphous silica on a support usually called paper or ink jet recording paper. Recording sheets provided with a layer have been used.
[0003]
For example, JP-A Nos. 55-51583, 56-157, 57-107879, 57-107880, 59-230787, 60-204390, 62-160277, 62-62. As disclosed in JP-A-184879, JP-A-62-183382 and JP-A-64-11877, a recording sheet obtained by applying a silicon-containing pigment such as silica to a paper support together with an aqueous binder has been proposed.
[0004]
JP-A-3-215082, JP-A-4-67986, JP-A-5-32037 and JP-A-10-81064 disclose a recording sheet obtained by applying silica fine particles or alumina sol together with a water-soluble binder to the surface of a support. Has been described.
[0005]
On the other hand, many recording sheets provided with an ink receiving layer mainly composed of a water-soluble polymer have been proposed. For example, in JP-A-60-168651, use of polyvinyl alcohol and a polyacrylic acid-based water-soluble polymer is used, in JP-A-60-262885, use of hydroxyethyl cellulose is used, and in JP-A-61-181679, carboxymethyl cellulose is used. In JP-A-61-193879, a mixture of water-soluble cellulose and polyvinylpyrrolidone is used. In JP-A-62-263084, a receptor layer formed from an aqueous gelatin solution having a specific pH is used. JP-A-1-146784 proposes the use of a mixture of gelatin and a surfactant, respectively.
[0006]
Also, many recording sheets containing a pigment such as amorphous silica and a specific binder have been proposed. For example, JP-A-6-32046, JP-A-6-143800, JP-A-7-32725, JP-A-7-149037, and JP-A-8-34160 all propose a combination of a pigment, a specific binder, and a specific compound. Have been.
[0007]
Further, a recording sheet having a water-soluble polymer swelling layer provided on a void layer composed of silica fine particles or alumina sol is disclosed in JP-A-9-323475, and a hydrophobic polymer is provided on a water-soluble polymer ink holding layer. A recording sheet having a microporous ink-permeable layer is described in JP-A-61-35275 and JP-A-62-196175, and has a porous layer made of a pigment on a layer made of a water-soluble polymer. Recording sheets are described in JP-A-62-140878, JP-A-62-222887, JP-A-3-72460, JP-A-7-186521, JP-A-10-29369, and the like.
[0008]
The above-mentioned conventional recording sheets do not simultaneously satisfy important performances such as ink absorption capacity, dryness after printing, and glossiness. In particular, in recent years, high-speed plotters having a large amount of ink and having a large amount of ink have become widespread, and the above performance has become increasingly important.
[0009]
[Problems to be solved by the invention]
Therefore, an object of the present invention is to provide an ink jet recording sheet having a large ink absorption capacity, a high drying property after printing, and a high gloss.
[0010]
[Means for Solving the Problems]
The object of the present invention is to use a waterproof support as a support, and to add a water-soluble polymer from a side closer to the support to 2 g / m 2.^Two5 g / m 2 of a silica containing a layer containing the above and synthetic silica by a gas phase method having an average particle diameter of primary particles of 50 nm or less.^TwoHaving at least a layer containingThe water-soluble polymer layer is a layer for absorbing ink by swelling of the water-soluble polymer, andThis is achieved by an ink jet recording sheet, wherein the water-soluble polymer is at least one selected from gelatin, polyvinylpyrrolidone, and a water-soluble cellulose derivative.
[0011]
Furthermore, a layer containing a water-soluble polymer and a layer containing synthetic silica by a gas phase method can be applied to printing of a large amount of ink by an ink jet recording sheet satisfying the following conditional expression 1.
Conditional expression 1 (A × 2) + (B × 8) ≧ 40
In the formula, A is 1 m of the silica synthesized by the gas phase method.²B represents 1 m of the water-soluble polymer.²Per unit weight.
[0012]
Use of synthetic silica fine particles by a gas phase method (hereinafter referred to as gas phase silica) is disclosed in the above-mentioned JP-A-60-204390, JP-A-10-81064, and the like. The use thereof is also described in the above-mentioned Japanese Unexamined Patent Publication and is well known. However, the present inventor has found that the above configuration of the present invention satisfies the ink absorption capacity, drying property and glossiness at the same time.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail.
Synthetic silica includes those obtained by a wet method and those obtained by a gas phase method. Usually, silica fine particles often refer to wet process silica. Examples of the wet process silica include: (1) a silica sol obtained by double decomposition of sodium silicate with an acid or the like through an ion exchange resin layer; (2) a colloidal silica obtained by heating and aging this silica sol; and (3) a gelation of the silica sol. By changing the formation conditions, silica gel in which primary particles of several μm to 10 μm have become siloxane-bonded three-dimensional secondary particles, and (4) silica sol, sodium silicate, sodium aluminate, etc. There are synthetic silicon compounds mainly composed of silicic acid, such as those obtained by heat generation.
[0014]
The fumed silica used in the present invention is also called a dry method as opposed to the wet method, and is generally produced by a flame hydrolysis method. Specifically, a method of making silicon tetrachloride by burning it with hydrogen and oxygen is generally known, but instead of silicon tetrachloride, silanes such as methyltrichlorosilane and trichlorosilane can be used alone or by silicon tetrachloride. And can be used in a mixed state. The fumed silica is commercially available as Aerosil from Nippon Aerosil Co., Ltd. and can be obtained.
[0015]
The average particle size of the primary particles of the fumed silica used in the present invention is 50 nm or less, preferably 5 to 30 nm. The feature of the fumed silica is that the primary particles are present in a state of being secondary aggregated by being connected in a network structure or a chain shape, whereby high ink absorption is obtained. Also, since the primary particle diameter is very small, high gloss can be maintained even when used for the uppermost layer of the recording sheet.
[0016]
Colloidal silica by a wet method has a very small primary particle diameter of several nm to several tens of nm, but because it exists as a primary particle in isolation, when a coating film is formed, the particles are present in a dense state. When used in the ink receiving layer, the gloss is high, but the porosity is poor and the ink absorption is reduced. In addition, secondary aggregated silica particles of several μm to 10 μm have high ink absorbency but reduce gloss. Alumina sol does not have the desired ink absorbency, and requires high-temperature heat treatment at about 120 ° C. for film formation and water resistance. Melts to form blisters).
[0017]
According to the present invention, by arranging fine-particle fumed silica on a layer made of a water-soluble polymer, the printed ink is quickly transmitted to the lower layer, and the transmitted ink is absorbed by swelling of the water-soluble polymer. It is based on the basic concept, and sets the fumed silica layer and the water-soluble polymer layer under specific conditions so as to be adaptable to a high-speed plotter with a large amount of ink. That is, it has been found that by satisfying the following conditional expression 1, it can be sufficiently applied to a high-speed plotter.
[0018]
Conditional expression 1 (A × 2) + (B × 8) ≧ 40
Here, A is 1 m²Weight of fumed silica per unit, at least 5 g / m²is necessary. B is 1m²Weight of water-soluble polymer per unit, at least 2 g / m²is necessary. The fumed silica has about twice the ink holding capacity per unit weight, and the water-soluble polymer (the polymer that dissolves in water at 5% by weight or more at normal temperature and pressure) has about 8 times the capacity per unit weight. The above conditional expression 1 was derived by empirically finding that there is an ink absorption capacity.
[0019]
The water absorption capacity of the water-soluble polymer was 4 g / m on a paper support coated with a polyethylene resin.²Apply the dried sample to a printer with an ink volume of 32 ml / m²Is determined empirically by visually observing whether or not the ink overflows when printing is performed under the conditions described above. It has been confirmed that any polymer that dissolves in water at 5% by weight or more at normal temperature and normal pressure has the above-mentioned ink absorption capacity.
[0020]
Simply providing only a layer containing a large amount of fumed silica or providing only a layer containing a large amount of a water-soluble polymer cannot simultaneously satisfy ink absorption, drying properties, and gloss. It is important to use both in combination, and it is also important to balance them. Therefore, in the above conditional expression 1, the ratio of (A × 2) to (B × 8) is preferably in the range of 5: 1 to 1: 5, particularly preferably in the range of 4: 1 to 1: 4, and more preferably 3: 1. : 1 to 1: 3 is preferred.
[0021]
The content of fumed silica is 1m²5 to 30 g is preferable, and 5 to 20 g is particularly preferable. The content of the water-soluble polymer is 1 m²The amount is preferably 2 to 10 g, particularly preferably 3 to 8 g.
[0022]
It is more preferable that the following conditional expression 2 be satisfied among the conditional expressions 1.
Conditional expression 2 (A × 2) + (B × 8) ≧ 50
[0023]
In the present invention, the upper layer containing fumed silica preferably has a binder in order to maintain the properties as a film. As the binder, various known binders can be used, but polyvinyl alcohol or cation-modified polyvinyl alcohol having a good binding property to fumed silica is preferably used.
[0024]
Among the polyvinyl alcohols, particularly preferred are those having a degree of saponification of 80 or more or completely saponified, and having an average degree of polymerization of 200 to 5,000, preferably 500 to 3,000 from the viewpoint of improving film formability and film brittleness. Things are used.
[0025]
Examples of the cation-modified polyvinyl alcohol include polyvinyl alcohols having a primary to tertiary amino group or a quaternary ammonium group in the seed chain or side chain of polyvinyl alcohol as described in, for example, JP-A-61-10483. Alcohol.
[0026]
Further, other hydrophilic binders can be used in combination, but the content is preferably 20% by weight or less based on polyvinyl alcohol. The amount of the hydrophilic binder used together with the fumed silica is 50% by weight or less, preferably 30 to 1% by weight, based on the fumed silica.
[0027]
Further, in order to improve the brittleness of the film, it is preferable to contain various oil droplets. As such oil droplets, a hydrophobic high boiling organic solvent having a solubility in water at room temperature of 0.01% by weight or less ( For example, particles obtained by polymerizing one or more polymerizable monomers such as liquid paraffin, dioctyl phthalate, tricresyl phosphate, and silicone oil) and polymer particles (for example, styrene, butyl acrylate, divinylbenzene, butyl methacrylate, and hydroxyethyl methacrylate). ) Can be contained. Such oil droplets can be preferably used in the range of 10 to 50% by weight based on the hydrophilic binder.
[0028]
In the case of the layer constitution of the present invention, when the lower water-soluble polymer layer absorbs ink and swells, fine cracks are likely to be formed in the upper layer of the fumed silica layer. This crack causes a reduction in gloss. In order to avoid this, it is preferable that the layer containing the fumed silica contains a hydrophilic binder together with a crosslinking agent for the binder. As the crosslinking agent, an inorganic or organic one known in the field of photographic materials can be used. For example, aldehyde compounds such as formaldehyde, glyoxal and glutaraldehyde, ketone compounds such as diacetyl and chloropentanedione, bis (2-chloroethyl urea) -2-hydroxy-4,6-dichloro-1,3,5 triazine, United States No. 3,288,775, compounds having a reactive halogen, divinyl sulfone, compounds having a reactive olefin as described in U.S. Pat. No. 3,635,718, N-methylol compounds as described in U.S. Pat. No. 2,732,316, U.S. Pat. Isocyanates as described in U.S. Pat. No. 3,103,437, aziridine compounds as described in U.S. Pat. Nos. 3,017,280 and 2,983,611, carbodiimide compounds as described in U.S. Pat. No. 3,100,704, and U.S. Pat. Poxy compounds, halogen carboxaldehydes such as mucochloric acid, dioxane derivatives such as dihydroxydioxane, chromium alum, potassium alum, zirconium sulfate, boric acid, inorganic hardeners such as borax, and the like. Two or more kinds can be used in combination. In particular, when polyvinyl alcohol is used as a binder, glyoxal, boric acid, and borax are preferred. The amount of the crosslinking agent added is preferably 0.5% by weight or more, particularly preferably 0.5 to 5% by weight, based on the water-soluble binder.
[0029]
In the present invention, as the water-soluble polymer used for the lower layer,One or more water-soluble polymers are used in combination from gelatin, polyvinylpyrrolidone and water-soluble cellulose derivatives.Particularly, it is preferable to use gelatin and another water-soluble polymer (for example, polyvinylpyrrolidone, carboxymethylcellulose, etc.) in combination.
[0030]
Among the above water-soluble polymers, gelatin is particularly preferably used. As the gelatin, any gelatin can be used as long as it is a collagen made of animal collagen, but gelatin made of collagen made from pig skin, cow skin, and cow bone is preferred. There is no particular limitation on the type of gelatin, but lime-treated gelatin, acid-treated gelatin, and gelatin derivatives (for example, Japanese Patent Publication Nos. 38-4854, 39-5514, 40-12237, and 42-345) No. 2,525,753, No. 2,594,293, No. 2,614,928, No. 2,763,639, No. 3,118,766, No. 3,132,945, No. 3,186,846, No. 3,31,553, No. 3,861,414, No. No. 1033189) can be used alone or in combination. Further, the jelly strength of gelatin (measured by a PAGI method and a bloom-type jelly strength meter) is preferably 150 g or more, particularly preferably 200 g or more.
[0032]
In the present invention, examples of the water-soluble cellulose derivative preferably used include water-soluble cellulose derivatives such as methyl cellulose, carboxymethyl cellulose, hydroxymethyl cellulose, hydroxyethyl cellulose, and hydroxypropyl cellulose. Among these water-soluble cellulose derivatives, carboxymethylcellulose, hydroxyethylcellulose, and methylcellulose are more preferable from the viewpoints of ink receptivity, dot reproducibility, and prevention of stickiness of a printed portion.
[0033]
In the present invention, the lower layer containing the water-soluble polymer preferably contains an aliphatic carboxylic acid having 4 or less carbon atoms (excluding the carbon number of the carboxyl group). This further improves the ink absorbency. Among the above carboxylic acids, dicarboxylic acid or tricarboxylic acid is particularly preferred, and examples thereof include malonic acid, succinic acid, malic acid, tartaric acid, and citric acid. The content of these carboxylic acids is at least 1% by weight, preferably 3 to 20% by weight, based on the water-soluble polymer.
[0034]
In the lower layer, together with the water-soluble polymer, amorphous porous silica, calcium carbonate, talc, clay, kaolin, calcium sulfate, barium sulfate, titanium oxide, zinc oxide, aluminum silicate, magnesium silicate, calcium silicate, and other inorganic pigments, colloidal silica, Colloidal inorganic fine particles such as colloidal alumina, thermosetting organic resin particles, and the like may be appropriately added. The lower layer may further contain the above-mentioned hardener, but it is preferable that the hardener is not substantially contained in consideration of ink absorbability. Even if it is contained, it is 0.5% by weight or less based on the water-soluble polymer.
[0035]
In the present invention, a surfactant can be added to the upper layer containing fumed silica or the lower layer containing a water-soluble polymer. The surfactant used may be any of anionic, cationic, nonionic and betaine types, and may be of low molecular weight or high molecular weight. One or two or more surfactants are added to the ink receiving layer coating solution. When two or more surfactants are used in combination, an anionic surfactant and a cationic surfactant are used in combination. It is not preferable. The amount of the surfactant added is preferably 0.001 g to 5 g, more preferably 0.01 to 3 g, per 100 g of the binder constituting the ink receiving layer.
[0036]
In the present invention, the upper layer or the lower layer may further contain, in addition to a surfactant and a hardener, a coloring dye, a coloring pigment, a fixing agent for an ink dye, an ultraviolet absorber, an antioxidant, a pigment dispersant, and a defoaming agent. Various known additives such as a leveling agent, a preservative, an optical brightener, a viscosity stabilizer, and a pH adjuster can also be added.
[0037]
In the present invention, the lower layer and the upper layer may be simultaneously coated in multiple layers, or the lower layer may be coated and dried, and then the upper layer may be coated and dried. The coating method in that case is not particularly limited, and a known coating method can be used. For example, there are a slide lip system, a curtain system, an extrusion system, an air knife system, a roll coating system, a rod bar coating system, and the like.
[0038]
Further, the drying after the application of the lower layer containing the water-soluble polymer and the upper layer containing the fumed silica is preferably carried out by a so-called cold drying method in which the gel is once brought into a gel state and then dried at a low temperature. This is a method of drying at a low temperature in order to form a uniform film surface by using the gelatin sol and gelation phenomena. The drying process is carried out in accordance with Yuji Harazaki, "Coating Engineering" (Asakura Shoten, 1975), as described in pages 278 to 281 of the material preheating period, the amount of evaporation of the solvent per unit time, that is, the evaporation rate of the solvent. After the constant-rate drying period of the drying process where is constant, the evaporation rate of the solvent gradually decreases, and almost no vapor is left (that is, the coating film has an equilibrium moisture content under almost ambient temperature and humidity conditions). The drying process is divided into three processes of a decreasing rate drying period, and a humidity control period may be provided if necessary. Normally, drying is completed when the equilibrium water content of about 5 to 8% is reached. However, if the temperature of the film surface during the drying process (this temperature is referred to as surface wet bulb temperature) is lowered, a uniform coating film is obtained. And a high quality ink receiving layer is obtained. After applying the ink receiving layer coating liquid, the coating layer is cooled and set (gelled) when the surface wet bulb temperature is below the gelling temperature of the coating liquid, and then the receiving layer is gradually cooled at a temperature below the gelling temperature of the coating liquid. To dry. After the solvent evaporates and the solid content concentration increases, the temperature may be raised to such an extent that the set does not return, and the solid content may be dried.
[0039]
In the present invention, the ink recording sheet has at least a two-layer structure including an upper layer containing fumed silica and a lower layer containing a water-soluble polymer, and further includes an ink absorbing layer, an ink fixing layer, an intermediate layer, a protective layer, and the like. You may.
[0040]
The support used in the present invention is a waterproof supportIs used.As the waterproof support, both a transparent support and an opaque support can be used. As the transparent support, any conventionally known ones can be used, for example, polyester resin, diacetate resin, triacetate resin, acrylic resin, polycarbonate resin, polyvinyl chloride, polyimide resin, cellophane, film or plate such as celluloid and A glass plate and the like are exemplified, and among these, a film made of polyethylene terephthalate is most preferably used.
[0041]
Such a transparent waterproof support preferably has a thickness of about 10 to 200 μm.
[0042]
As the opaque waterproof support, any of conventionally known ones such as synthetic paper, resin-coated paper, opaque film containing pigment, and foam film can be used. From the viewpoint of gloss and smoothness, resin-coated paper and various films are more preferable.However, a film made of resin-coated paper similar to a photographic support from the feeling of touch and luxuriousness and a pigmented polyethylene terephthalate having high whiteness and strength is preferred. More preferably used.
[0043]
The base paper constituting the resin-coated paper as the waterproof support preferably used in the present invention is not particularly limited, and generally used paper can be used. More preferably, for example, the base paper is used for a photographic support. Such a smooth base paper is preferable. As the pulp constituting the base paper, natural pulp, recycled pulp, synthetic pulp or the like may be used alone or in combination of two or more. The base paper is blended with additives generally used in papermaking, such as a sizing agent, a paper strength enhancer, a filler, an antistatic agent, a fluorescent whitening agent, and a dye.
[0044]
Further, a surface sizing agent, a surface strength agent, a fluorescent whitening agent, an antistatic agent, a dye, an anchoring agent and the like may be applied on the surface.
[0045]
The thickness of the base paper is not particularly limited, but preferably has good surface smoothness such as compressing the paper by applying pressure during or after papermaking with a calender or the like, and its basis weight is 30 to 250 g. / M²Is preferred.
[0046]
As the resin of the resin-coated paper, a polyolefin resin or a resin that is cured by an electron beam can be used. The polyolefin resin is a low-density polyethylene, high-density polyethylene, polypropylene, polybutene, a homopolymer of olefins such as polypentene or a copolymer of two or more olefins such as an ethylene-propylene copolymer and mixtures thereof, Those having various densities and melt viscosity indices (melt index) can be used alone or in combination.
[0047]
Also, in the resin of the resin-coated paper, white pigments such as titanium oxide, zinc oxide, talc, calcium carbonate, fatty acid amides such as stearic acid amide and arachidic amide, zinc stearate, calcium stearate, aluminum stearate, stearin Fatty acid metal salts such as magnesium oxide, antioxidants such as Irganox 1010 and Irganox 1076, blue pigments and dyes such as cobalt blue, ultramarine blue, cecilian blue, phthalocyanine blue, and magenta such as cobalt violet, fast violet, and manganese purple It is preferable to add various additives such as pigments and dyes, fluorescent brighteners and ultraviolet absorbers in an appropriate combination.
[0048]
In the case of polyolefin resin on a running base paper, the resin-coated paper that is preferably used in the present invention is manufactured by a so-called extrusion coating method in which a heated and molten resin is cast, and both surfaces thereof are coated with the resin. You. In the case of a resin that is cured by an electron beam, the resin is applied by a commonly used coater such as a gravure coater or a blade coater, and then irradiated with an electron beam to cure and coat the resin. Further, it is preferable to perform an activation treatment such as a corona discharge treatment or a flame treatment on the base paper before coating the resin on the base paper. The surface (surface) of the support on which the ink receiving layer is applied has a glossy surface, a matte surface, and the like, depending on the application, and the glossy surface is used particularly favorably. Although it is not necessary to coat the back surface with a resin, it is preferable to coat the resin from the viewpoint of preventing curling. The back surface is usually a matte surface, and the front surface or both front and back surfaces can be subjected to activation treatment such as corona discharge treatment and flame treatment as required. The thickness of the coating resin layer is not particularly limited, but is generally 5 to 50 μm thick on both the front and back surfaces.
[0049]
The support in the present invention may be coated with various back coat layers for antistatic properties, transport properties, curling prevention properties, and the like. The back coat layer can contain an inorganic antistatic agent, an organic antistatic agent, a hydrophilic binder, a latex, a curing agent, a pigment, a surfactant and the like in an appropriate combination.
[0050]
【Example】
Hereinafter, the present invention will be described in detail with reference to examples, but the contents of the present invention are not limited to the examples.
[0051]
Example 1
As a support, a pulp blend of LBKP (50 parts) and LBSP (50 parts) of 120 g / m 2²25 g / m 2 of a resin composition comprising low-density polyethylene (70 parts), high-density polyethylene (20 parts) and titanium oxide (10 parts) on the surface of the base paper²A resin composition composed of high-density polyethylene (50 parts) and low-density polyethylene (50 parts) was applied on the back surface at 25 g / m²A coated resin-coated paper was prepared.
[0052]
The following lower layer coating solution was applied and dried on the support, and the upper layer coating solution was applied and dried to prepare various ink jet recording sheets. Various recording sheets were prepared as shown in Table 1 with respect to the type and amount of the water-soluble polymer and the type and amount of the inorganic fine particles.
[0053]

[0054]

[0055]
[Table 1]

[0056]
Furthermore, as Comparative Example 7, Comparative Example 7 was obtained by applying the lower layer of the present invention 1 to the upper layer and coating the upper layer to the lower layer. These 10 types of recording sheets were tested for ink absorption capacity, drying property, and glossiness using an inkjet printer (MJ930 manufactured by Epson Corporation) by the following methods. Table 2 shows the results.
[0057]
<Ink absorption capacity>
The state of ink overflow at the time of discharging 100% of the maximum ink amount of each of the Y, M, C, and K inks was visually observed and evaluated according to the following criteria.
A: No overflow immediately after printing.
：: Slight overflow immediately after printing, but absorbed within about 10 seconds.
Δ: overflowed immediately after printing and absorbed within about 20 seconds.
×: overflowing immediately after printing, it takes 30 seconds or more to absorb.
[0058]
<Dryability>
After a certain period of time after printing under the above conditions, plain paper was overlaid and allowed to stand, and the time until ink was not transferred to plain paper was measured and evaluated according to the following criteria.
◎: within 2 minutes
○: 2 to 4 minutes
Δ: 4 to 6 minutes
×: 6 minutes or more
[0059]
<Gloss>
The 60-degree specular gloss according to the specular gloss measurement method (JIS-Z8741) was measured using a gloss meter (VGS-1D manufactured by Nippon Denshoku Industries Co., Ltd.).
[0060]
[Table 2]

[0061]
From the above results, it can be seen that the recording sheet of the present invention has a large ink absorption capacity and is excellent in drying property and glossiness.
[0062]
Example 2
Except that the fumed silica A having an average primary particle diameter of 7 nm or the fumed silica having an average primary particle diameter of 20 nm was used instead of the fumed silica A used for the recording sheet of the present invention 2 in Example 1. Prepared two types of recording sheets of the present invention in the same manner as the recording sheet of the present invention 2. As a result of a test performed in the same manner as in Example 1, the same results as those of the recording sheet of the second embodiment were obtained for each of the two types of recording sheets.
[0063]
Example 3
Instead of the gelatin used for the recording sheet of the present invention 2 in Example 1,
(1) 5 g / m of polyvinylpyrrolidone²
(2) 5 g / m of carboxymethyl cellulose²
(3) Gelatin 2.5g / m²And polyvinylpyrrolidone 2.5 g / m²
(4) Gelatin 2.5 g / m²And carboxymethylcellulose 2.5 g / m²
Was used in the same manner as the recording sheet of the present invention 2 except that each was used, to thereby prepare four types of recording sheets of the present invention. As a result of the test performed in the same manner as in Example 1, the same results as those of the recording sheet of the second embodiment were obtained for all of the four types of recording sheets.
[0064]
Example 4
According to Example 1, recording sheets of the present invention as shown in Table 3 were prepared.
[0065]
[Table 3]

[0066]
The recording sheet created by the method described above was ejected at 90% of the maximum ink amount of each of the Y, M, C, and K inks using an ink-jet plotter having a large ink amount (Novajet PRO, GA ink manufactured by Encad). Printing was performed, and the ink absorption capacity, drying property, and glossiness were evaluated in the same manner as in Example 1. Table 4 shows the results.
[0067]
[Table 4]

[0068]
From the above results, it is understood that a layer configuration satisfying (A × 2) + (B × 8) ≧ 40 can be sufficiently applied to a plotter having a larger amount of ink. Particularly, by satisfying (A × 2) + (B × 8) ≧ 50, a greater effect can be obtained.
[0069]
Example 5
The recording sheets of the inventions 10 to 21 were prepared in the same manner as in the recording sheets of the inventions 4 to 9 of Example 4 except that succinic acid was added to the lower layer in an amount of 10% by weight based on the amount of gelatin or malic acid in an amount of 5% by weight. Created. These recording sheets were printed using an ink-jet plotter having a large amount of ink (Novajet PRO, GA ink manufactured by Encad) at 100% of the maximum ink amount of each of the Y, M, C, and K inks, and the ink was absorbed. The capacity, drying property and glossiness were evaluated in the same manner as in Example 1. Table 5 shows the results.
[0070]
[Table 5]

[0071]
From the above results, it can be seen that by including an aliphatic carboxylic acid having 4 or less carbon atoms such as succinic acid and malic acid in the lower water-soluble polymer layer, it is possible to sufficiently cope with a further increase in the ink ejection amount.
[0072]
Example 6
The recording sheets 22, 23 of the present invention were prepared in the same manner as in the ninth embodiment except that boric acid or glyoxal was added as a crosslinking agent to the upper layer of the recording sheet of the ninth embodiment in an amount of 1% by weight based on polyvinyl alcohol. Created. In the same manner as in Example 4, the ink absorption capacity, drying property, and glossiness were evaluated. As a result, the ink absorbing capacity and the drying property of the recording sheets of the present invention 22 and 23 were almost the same as those of the present invention 9, and the glossiness was further increased by 5%. This increase in gloss is due to the fact that the inclusion of a hardener in the upper layer prevented the generation of minute cracks due to distortion of the upper layer due to swelling of the lower layer during ink absorption.
[0073]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to the inkjet recording sheet of this invention, an ink absorption capacity, drying property, and glossiness can be simultaneously satisfy | filled. Particularly, it is suitably used for a high speed plotter having a large amount of ink. By including a specific carboxylic acid together with the water-soluble polymer in the lower layer, the ink absorption capacity and the drying property are further improved. In addition, by including a binder and a crosslinking agent thereof together with fumed silica in the upper layer, fine cracks can be prevented and gloss can be further improved.

Claims (4)

A waterproof support was used as a support, and a layer containing ² g / m ² or more of a water-soluble polymer and 5 g / m ² of synthetic silica by a gas phase method having an average primary particle size of 50 nm or less were used from the side closer to the support. ^At least a layer containing at least ^two, wherein the water-soluble polymer layer is a layer for absorbing ink by swelling of the water-soluble polymer , and the water-soluble polymer is gelatin, polyvinylpyrrolidone, water-soluble cellulose. An ink jet recording sheet, which is at least one selected from derivatives. 2. The sheet according to claim 1, wherein the layer containing the water-soluble polymer and the layer containing the fumed silica satisfy the following conditional expression 1.
Conditional expression 1 (A × 2) + (B × 8) ≧ 40
In the formula, A represents the content weight per m ^{2 of the} silica synthesized by the gas phase method, and B represents the content weight per m ^{2 of the} water-soluble polymer. The ink jet recording sheet according to claim 1, wherein the layer containing the silica synthesized by the gas phase method contains a binder and a crosslinking agent thereof. The inkjet recording sheet according to claim 1, wherein the layer containing the water-soluble polymer contains an aliphatic carboxylic acid having 4 or less carbon atoms.