JP3784239B2 - Backlit inkjet recording material - Google Patents

Description

【００８６】
結果；実施例２は、実施例１で支持体として用いたポリエチレンテレフタレートフィルムの上にプライマー層を設けた場合であるが、実施例１よりインク受容層のヘーズ値は小さく透明性が向上しており、透過光による画像鮮鋭性は実施例１，２ともに良好であった。実施例２で気相法シリカを平均一次粒径が１２ｎｍの気相法シリカに代えた実施例３は、写像性が若干下がりギラギラ感が低下傾向で、インク吸収性は向上し、画像鮮鋭性は良好であったが、ヘーズ値が増えてインク受容層の透明性は低下傾向であった。実施例４は実施例２で平均一次粒径が７ｎｍと１２ｎｍの気相法シリカを３０／７０の比率で混合した場合であるが、ヘーズ値が若干高くなったが、インク吸収性は良化し、画像鮮鋭性は良好であった。参考例１は実施例２でインク受容層の湿式法シリカを１６部まで増やした場合であるが、写像性は低下してギラギラ感は良好であるが、インク吸収性が低下し、ヘーズ値は高く、透過光による画像の鮮鋭性は実使用で下限であった。実施例５は平均粒径１０μｍの湿式法シリカを２部使用した場合であるが、写像性が高くギラギラ性は実使用下限であり、ヘーズ値が高目で画像鮮鋭性、表面強度も低下傾向であり、平均粒径２μｍの湿式法シリカを１６部まで増やした参考例１より手触りのざらつきが増大し、実使用下限のレベルであった。実施例６は実施例１で酢酸ジルコニウムを抜いた場合であるが、ヘーズ値が若干高く透明性は低下したが画像鮮鋭性等は問題の無いレベルであった。参考例２はゼラチンとポリビニルアルコ−ルの系に平均粒径２μｍの湿式法シリカを５部含有させた場合であるが、実施例１よりヘーズ値は低く透明性は良好であったがインク吸収性は低目であり、印字画像再現性の低下により画像鮮鋭性は低下し、写像性は高目でギラギラ感も実施例１より増大したが実使用可能であった。
【００８７】
比較例１は、実施例１で湿式法シリカを抜いた場合であるが、ヘーズ値は良好で画像鮮鋭性も良好であるが、写像性が高く、ギラギラ感に劣った。比較例２は、参考例２で湿式法シリカを抜いた場合であるが、ヘーズ値は非常に良好であるが写像性が高く、ギラギラ感が増大して実使用では問題のレベルであった。比較例３は実施例１で一次粒子の平均粒径７ｎｍの気相法シリカと平均粒径１０μｍの湿式法シリカとの重量比を８１／１９とした場合であり、写像性は低く良好であるが、インク吸収性が悪く、インク受容層のヘーズ値が高く透過光による画像鮮鋭性も実使用で問題の有るレベルであった。
【００８８】
【発明の効果】
上記結果から明らかなように、本発明により、特に医療用途でバックライト方式で使用しても戻り光によるギラギラ性の問題が無い、透明性が高く（ヘーズ値が低い）、インク吸収性が高く、画像再現性や表面強度の良好なバックリット用インクジェット記録材料が得られる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ink-jet recording material for backlit, particularly for medical use, having high ink absorbency and excellent transparency, and in use in a backlight system in which an image is viewed by transmitted light from the opposite side of the printed surface. The present invention relates to an ink-jet recording material for backlit which has sufficient transparency and does not have a problem of unsightly image appearance due to reflected light (returned light) of external light other than transmitted light.
[0002]
[Prior art]
As a recording material used in the ink jet recording method, a porous material composed of a water-soluble binder and a pigment such as a hydrophilic polymer ink receiving layer or amorphous silica on a support called ordinary paper or ink jet recording paper. Recording materials provided with an ink receiving layer are known.
[0003]
For example, as disclosed in JP-A-56-080489, JP-A-59-174381, JP-A-60-220750, JP-A-61-32788, JP-A-63-160875, JP-A-3-69388, etc. A recording material in which a hydrophilic polymer such as alcohol is coated on a support has been proposed.
[0004]
For example, JP-A Nos. 55-51583, 56-157, 57-107879, 57-107880, 59-230787, 62-160277, 62-184879, 62-183382 And a recording material obtained by applying a silicon-containing pigment such as silica or an alumina sol together with an aqueous binder to a paper support as disclosed in JP-A-64-11877, JP-A-3-21508, and JP-A-4-67986. Has been proposed.
[0005]
In addition, JP-B-3-56552, JP-A-2-188287, JP-A-8-132728, JP-A-10-81064, JP-A-10-119423, JP-A-10-175365, JP-A-10-203006, 10-217601, 11-20300, 11-20306, 11-34481 use synthetic silica fine particles by a vapor phase method (hereinafter referred to as vapor phase method silica). A recording material is disclosed.
[0006]
On the other hand, production of a transparent recording sheet or a medical film by an ink jet recording method has also been studied. It is important for these recording sheets to have high transparency in addition to the ink absorptivity generally required for ink jet recording materials. In particular, in medical applications, reflected light of external light other than transmitted light (return light) There is a problem that the image is difficult to see due to the glare.
[0007]
Japanese Patent Application Laid-Open No. 7-276789 discloses a recording material in which the average particle diameter of primary particles is 10 nm or less and the weight ratio of silica fine particles to water-soluble resin is 1.5: 1 to 10: 1. However, there was no description about the improvement of the glare property due to the reflected light (returned light) of the external light that is particularly important for medical use.
[0008]
[Problems to be solved by the invention]
The object of the present invention is to have high ink absorption and transparency, good image reproducibility, and particularly for use in a backlight system in which light is irradiated from the surface opposite to the print surface and the image is observed from the print surface in medical applications. However, an object of the present invention is to provide an ink jet recording material for backlit which is not difficult to view an image due to return light of external light.
[0009]
[Means for Solving the Problems]
As a result of sincerity studies, it has been found that the above object of the present invention can be achieved by the following means.
[0011]
In a backlit inkjet recording material for providing an ink receiving layer on a light-transmitting support and irradiating light from the surface opposite to the printing surface to observe an image from the printing surface , the ink receiving layer comprises secondary particles. Gas phase method silica and hydrophilic polymer as inorganic fine particles having an average particle size of less than 0.5 μm, and wet method silica as an inorganic pigment having an average particle size of 0.5 μm or more, and the inorganic pigment has a recording material unit area An ink jet recording material for backlit, characterized in that it contains 0.1 to 5 g / m ² and the haze value defined by JIS-K-7105 of the ink receiving layer is 18% or less .
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail.
In the present invention, the ink receiving layer coated on the light-transmitting support has inorganic fine particles with an average secondary particle size of less than 0.5 μm, inorganic pigments with an average particle size of 0.5 μm or more, and hydrophilic containing sex polymer, timely crosslinking agent, a cationic polymer, you containing a surfactant (hereinafter referred to as "void ink-receiving layer"). The ink receiving layer coating solution is applied so that a coating layer having a thickness of several tens to several hundreds of μm is formed on the support, and then dried. In a preferred example of the production method, the ink receiving layer applied to the light-transmitting support is once cooled in an atmosphere of 20 ° C. or lower and then dried in a drying step. Usually, the ink-receiving layer coating liquid before coating is kept at a temperature of about 30 to 50 ° C., and high transparency can be obtained by cooling once after coating.
[0019]
In comparison between a general swellable ink receiving layer and a void ink receiving layer, the former tends to be inferior in ink absorptivity and has a characteristic that the surface is likely to have a glare. In particular, when used for medical purposes, ink absorbency is an important characteristic because an image printed with an ink jet must sufficiently reproduce the actual product. In addition, an increase in surface glare is not desirable when using the backlight method in which light is irradiated from the opposite surface to observe the image from the printed surface, because it becomes difficult to see the image due to the return light of the external light. . As described above, the void ink receiving layer is preferable for medical use and the like used in the backlight system.
[0021]
As the inorganic pigment having an average particle size of 0.5 μm or more used in the present invention, wet-process silica is selected because of the effect of reducing ink absorbability and surface glare. If the average particle size is smaller than 0.5 μm, the effect of reducing the return light due to light reflection cannot be obtained. Preferably, the average particle size is larger than 1 μm from the effect of improving the glare feeling. The upper limit of the average particle diameter is not particularly limited, but if it is increased, the roughness of the surface of the ink receiving layer is increased, and when printing is repeated, it becomes difficult to slip and the touch becomes worse. The average particle diameter of the inorganic pigment means the average particle diameter of secondary particles when used in the state of secondary particles. The content of the average particle size is more than 0.5μm inorganic pigments are common in the present invention is limited by the haze value, 0.1-5 g / m ² is contained in the recording material per unit area in. Preferably 0.1 to ² g / m ^{2 is} contained.
[0022]
In the present invention, the inorganic fine particles having an average secondary particle size of less than 0.5 μm used in the case of the void ink receiving layer include silica vapor phase method in terms of high printing density, clear image, and low production cost. Is selected . The average particle size of the primary particles is preferably about 3 to 50 nm from the transparency of the ink receiving layer and the print image reproducibility. Particularly for medical use, since the reproducibility of a printed image is required, the average particle size of the inorganic fine particles used is preferably small.
[0023]
Synthetic silica is classified into a wet method and a gas phase method. In general, silica fine particles often refer to wet process silica. As the wet method silica, (1) a silica sol obtained through metathesis with an acid of sodium silicate or through an ion exchange resin layer, or (2) colloidal silica obtained by heating and aging this silica sol, or (3) gelling the silica sol By changing the production conditions, silica gel in which primary particles of several to 10 μm are converted into three-dimensional secondary particles having siloxane bonds, and (4) silica sol, sodium silicate, sodium aluminate, etc. There are synthetic silicic acid compounds mainly composed of silicic acid such as those obtained by heating.
[0024]
Vapor phase silica is also called a dry method as opposed to a wet method, and is generally made by a flame hydrolysis method. Specifically, a method of making silicon tetrachloride by burning with hydrogen and oxygen is generally known, but silanes such as methyltrichlorosilane and trichlorosilane can be used alone or silicon tetrachloride instead of silicon tetrachloride. Can be used in a mixed state. Vapor phase method silica is commercially available as Aerosil from Nippon Aerosil Co., Ltd. and QS type from Tokuyama Co., Ltd., and can be obtained.
[0025]
The vapor-phase process silica used in the present invention has an average primary particle diameter of 3 to 30 nm in terms of transparency and gloss. However, surface glare tends to be easily generated by external light.
[0026]
In particular, at least one kind of silica belonging to monodispersed silica A having an average primary particle size of 3 nm or more and less than 10 nm and a dispersity of 1 or less, and a single particle having an average primary particle size of 10 to 30 nm and a dispersity of 1 or less. When at least one kind of silica belonging to the dispersed silica B is used in combination, the ink receiving layer has transparency and good ink absorbability. The combined effect is that the difference in average particle size between the silica having the largest average particle size of the primary particles belonging to the vapor-phase process silica A and the silica having the smallest average particle size of the primary particles belonging to the silica B is 2 nm or more. It is preferable when taking out.
[0027]
The average particle size of the primary particles of the present invention is the diameter of a circle equal to the projected area of each of 100 particles existing in a certain area by electron microscope observation of particles dispersed to such an extent that the primary particles can be discriminated. The average particle size and standard deviation were determined as the particle size. Similarly, the secondary particles were obtained by observing the particles dispersed with a gentle shear force with an electron microscope. The degree of dispersion is obtained as a ratio of standard deviation / average particle diameter. The smaller the value, the smaller the number of particles deviating from the average particle diameter, and the higher the monodispersibility.
[0028]
In the present invention, the weight ratio of the inorganic fine particles having an average secondary particle size of less than 0.5 μm and the inorganic pigment having an average particle size of 0.5 μm or more is roughly determined mainly by the haze value, image clarity and ink absorbability of the ink receiving layer. Generally, it is 82/18 to 99/1, preferably 90/10 to 98/2. When the amount of the inorganic pigment exceeds 18 parts, the decrease in transparency is large, and when the amount is less than 1 part, the effect of reducing the return light decreases.
[0029]
In the present invention, the solid content per unit area of the ink receiving layer and is generally at 10 g / m ² or more, the range of 13~35g / m ² is preferred.
[0030]
The void ink receiving layer of the present invention has a binder in order to maintain the properties as a film. As the binder, a hydrophilic polymer that has high transparency and high ink permeability is preferably used. In using the hydrophilic polymer, it is important that the hydrophilic polymer does not swell at the initial permeation of the ink and block the gap. From this viewpoint, the hydrophilic polymer is exemplified as the hydrophilic polymer used in the swellable ink receiving layer. A hydrophilic polymer having a low swelling property at a relatively near room temperature is preferably used from among various types. Particularly preferred hydrophilic polymers are fully or partially saponified polyvinyl alcohol or cation-modified polyvinyl alcohol.
[0031]
Particularly preferred among the polyvinyl alcohols are those having a saponification degree of 80 or more or those having been completely saponified. Polyvinyl alcohol having an average degree of polymerization of 500 to 5000 is preferred.
[0032]
The cation-modified polyvinyl alcohol has a primary to tertiary amino group or a quaternary ammonium group in the main chain or side chain of the polyvinyl alcohol as described in, for example, JP-A-61-10383. Polyvinyl alcohol.
[0033]
Moreover, although other hydrophilic binders can be used in combination, it is preferably about 20% by weight or less with respect to polyvinyl alcohol.
[0034]
In the present invention, the weight ratio of the hydrophilic binder to the inorganic fine particles and the inorganic pigment in the void ink-receiving layer is mainly determined by the transparency, ink absorbability and surface strength of the ink-receiving layer. It is 60-100 / 8, Preferably it is the range of 100 / 50-100 / 10. When the ratio of the inorganic fine particles to the hydrophilic binder is increased, the ink absorbability is improved, but the transparency is lowered, cracking at the time of drying tends to occur, the surface strength is lowered, and the powder falls easily. Conversely, when the ratio is lowered, the transparency and the surface strength are improved, but the ink absorbability is lowered.
[0035]
In the ink jet recording material of the present invention, the haze value defined in JIS-K-7105 of the ink receiving layer is 18% or less. When the numerical value is high, the sharpness of the image is deteriorated particularly when used in a medical backlight system, and the glare is increased, which makes it easy to make a mistake.
[0036]
In the present invention, when the haze value of the ink jet recording material is Ha, the haze value of the support used is Hb, and the haze value of the ink receiving layer is Hc, it is simply Ha−Hb to obtain Hc. calculate.
[0037]
Glittering, which is a problem particularly in medical applications, occurs when external light is reflected from the surface of the ink receiving layer, but even when evaluated at a gloss value of 60 degrees or 75 degrees, a sufficient correlation with the glittering is not obtained. It was. As a result of various examinations of the evaluation method, it was found that the relationship between the image clarity C value obtained by the measurement of image clarity and the feeling of glare due to the return light as reflected light is deep.
[0038]
The image clarity of the present invention is an index of how sharply the image is projected when an object appears on the surface of the coating film, and is defined in JIS-H-8686. In this invention, Suga Test Instruments Co., Ltd. image clarity measuring device is used, and it evaluates by the image clarity C value obtained using the width | variety of 2.0 mm of an optical comb. The larger the image clarity C value is, the better the surface property is, and it is preferable for general photography, printing and publishing applications, but in the case of an ink jet recording material for backlit using a light-transmitting support, the surface of the ink receiving layer It was found that when the image clarity of the image was high, the image of the transmitted light was glaring and difficult to see due to light reflection by external light. In particular, when it is necessary to make a serious judgment from the image content, such as medical use, improvement of the glittering is particularly important. In the present invention, the image clarity C value is generally 85% or less, preferably 83% or less, and more preferably 80% or less.
[0039]
The ink receiving layer of the present invention preferably contains a cationic compound. Examples of the cationic compound used in the present invention include cationic polymers and water-soluble metal compounds used for the purpose of improving water resistance. Cationic polymers tend to decrease transparency when used in combination with vapor phase silica, but water-soluble metal compounds suppress the occurrence of fine cracks and conversely improve transparency. Therefore, the present invention has the advantages that the ink absorption is good, the water resistance is high, and the transparency is high due to the mixing of the two kinds of vapor phase silica and the water-soluble metal compound.
[0040]
Examples of the cationic polymer used in the present invention include polyethyleneimine, polydiallylamine, polyallylamine, JP-A-59-20696, 59-33176, 59-33177, 59-1555088, and 60-11389. No. 60-49990, No. 60-83882, No. 60-109894, No. 62-198493, No. 63-49478, No. 63-115780, No. 63-280681, JP-A-1-40371. No. 6-234268, No. 7-125411, No. 10-193376, and the like, and polymers having a primary to tertiary amino group and a quaternary ammonium base are preferably used. The molecular weight of these cationic polymers is preferably 5,000 or more, more preferably about 5,000 to 100,000.
[0041]
The amount of these cationic polymers used is 1 to 10% by weight, preferably 2 to 7% by weight, based on the inorganic fine particles.
[0042]
Examples of the water-soluble metal compound used in the present invention include water-soluble polyvalent metal salts. Examples include water-soluble salts of metals selected from calcium, barium, manganese, copper, cobalt, nickel, aluminum, iron, zinc, zirconium, chromium, magnesium, tungsten, and molybdenum. Specifically, for example, calcium acetate, calcium chloride, calcium formate, calcium sulfate, barium acetate, barium sulfate, barium phosphate, manganese chloride, manganese acetate, manganese formate dihydrate, manganese ammonium sulfate hexahydrate, chloride chloride Dicopper, ammonium copper (II) chloride dihydrate, copper sulfate, cobalt chloride, cobalt thiocyanate, cobalt sulfate, nickel sulfate hexahydrate, nickel chloride hexahydrate, nickel acetate tetrahydrate, nickel sulfate Ammonium hexahydrate, nickel amidosulfate tetrahydrate, aluminum sulfate, aluminum sulfite, aluminum thiosulfate, polyaluminum chloride, aluminum nitrate nonahydrate, aluminum chloride hexahydrate, ferrous bromide, ferric chloride Ferrous, ferric chloride, ferrous sulfate, ferric sulfate, zinc bromide, zinc chloride, zinc nitrate six Japanese, Zinc sulfate, Zirconium acetate, Zirconium chloride, Zirconium chloride octahydrate, Hydroxy zirconium chloride, Chromium acetate, Chromium sulfate, Magnesium sulfate, Magnesium chloride hexahydrate, Magnesium citrate nonahydrate, Phosphorus tungsten Sodium tungstate, sodium tungsten citrate, 12 tungstophosphoric acid n hydrate, 12 tungstosilicic acid 26 hydrate, molybdenum chloride, 12 molybdophosphoric acid n hydrate, and the like. In view of characteristics, a zirconium-based compound is preferable.
[0043]
Examples of the cationic compound include a basic polyaluminum hydroxide compound that is an inorganic aluminum-containing cationic polymer. The basic polyaluminum hydroxide compound has a main component represented by the following general formula 1, 2, or 3, for example, [Al ₆ (OH) ₁₅ ] ³⁺ , [Al ₈ (OH) ₂₀ ] ⁴⁺ , [ It is a water-soluble polyaluminum hydroxide that stably contains a basic and high-molecular polynuclear condensed ion such as Al ₁₃ (OH) ₃₄ ] ⁵⁺ , [Al ₂₁ (OH) ₆₀ ] ³⁺ , and the like.
[0044]
[Al ₂ (OH) _n Cl _6-n ] _m ·· Formula 1
[Al (OH) ₃ ] _n AlCl ₃ .. Formula 2
Al _n (OH) _m Cl _(3n-m) 0 <m <3n Formula 3
[0045]
These are water treatment agents from Taki Chemical Co., Ltd. under the name of polyaluminum chloride (PAC), from Asada Chemical Co., Ltd. under the name of polyaluminum hydroxide (Paho), and from Riken Green Co., Ltd. It is marketed under the name of Purachem WT and from other manufacturers for the same purpose, and various grades can be easily obtained. In the present invention, these commercially available products can be used as they are, but there are also products having an inappropriately low pH, and in that case, the pH can be appropriately adjusted and used.
[0046]
In the present invention, the content of the ink receiving layer of the water-soluble metal ^{compound, 0.1g / m 2 ~10g / m} 2, and preferably from ^{0.2g / m 2 ~5g / m 2} .
[0047]
Two or more of the above cationic compounds can be used in combination. For example, a cationic polymer and a water-soluble metal compound may be used in combination.
[0048]
The ink receiving layer in the present invention preferably contains various oil droplets in order to improve the brittleness of the film, but such oil droplets have a solubility in water at room temperature of 0.01% by weight or less. Hydrophobic high-boiling organic solvents (for example, liquid paraffin, dioctyl phthalate, tricresyl phosphate, silicone oil) and polymer particles (for example, styrene, butyl acrylate, divinylbenzene, butyl methacrylate, hydroxyethyl methacrylate, and other polymerizable monomers) Particles obtained by polymerizing one or more of the above. Such oil droplets can be preferably used in the range of 5 to 50% by weight based on the hydrophilic binder.
[0049]
In the present invention, the ink receiving layer can be hardened with a suitable hardener for the purpose of improving water resistance and dot reproducibility. Specific examples of the hardener include aldehyde compounds such as formaldehyde and glutaraldehyde, ketone compounds such as diacetyl and chloropentanedione, bis (2-chloroethylurea) -2-hydroxy-4,6-dichloro-1 , 3,5 triazine, a compound having a reactive halogen as described in US Pat. No. 3,288,775, divinyl sulfone, a compound having a reactive olefin as described in US Pat. No. 3,635,718, N-methylol compounds as described in Japanese Patent No. 2,732,316, isocyanates as described in US Pat. No. 3,103,437, US Pat. Nos. 3,017,280 and 2,983,611 described Aziridines such as carbodiimide compounds as described in US Pat. No. 3,100,704, Epoxy compounds as described in No. 3,091,537, halogen carboxaldehydes such as mucochloric acid, dioxane derivatives such as dihydroxydioxane, chromium alum, zirconium sulfate, boric acid and inorganic hardeners such as borate, etc. These can be used alone or in combination of two or more. The addition amount of the hardener is preferably 0.01 to 40 g, more preferably 0.1 to 30 g with respect to 100 g of the hydrophilic polymer constituting the ink receiving layer.
[0050]
In the present invention, in addition to the surfactant and the hardener, the ink receiving layer further includes a coloring dye, a coloring pigment, an ink dye fixing agent, an ultraviolet absorber, an antioxidant, a pigment dispersant, and an antifoaming agent. , Various known additives such as leveling agents, preservatives, optical brighteners, viscosity stabilizers, and pH adjusters may be added.
[0051]
In the present invention, the coating method is not particularly limited, and a known coating method can be used. For example, there are a slide bead method, a curtain method, an extrusion method, an air knife method, a roll coating method, a Ked bar coating method, and the like.
[0052]
In the present invention, the ink receiving layer may be composed of a single layer or a plurality of layers. In the case of multiple layers, the layers may be divided according to function. When two or more ink-receiving layers are simultaneously applied, it means the total solid content ratio and the total application amount of all layers.
[0053]
Examples of the light-transmitting support used in the present invention include polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate, diacetate resins, triacetate resins, cellulose ester resins such as nitrocellulose and cellulose acetate, and polyolefin resins. And plastic resin films such as acrylic resin, polycarbonate resin, polyvinyl chloride, polyimide resin, polysulfone, polyphenylene oxide, cellophane, and celluloid. In particular, a polyester film is preferably used in terms of properties such as heat resistance and price. The thickness of these resin film supports is preferably about 50 to 250 μm from the viewpoint of curling property and ease of handling.
[0054]
When adjusting the transparency and color tone of the light-transmitting support, for example, it is prepared by blending inorganic fine particles and the like with a thermoplastic resin. Examples of the inorganic fine particles include calcium carbonate, titanium dioxide, talc, silica, and carbon black. Color pigments such as can be used. In the present invention, the support preferably has an opacity of 60% or less. When it is larger than 60%, the light transmittance is inferior and the image becomes unclear. If it is lower than 5%, the transmitted light becomes strong and it becomes difficult to see the image depending on the illumination of the light source. Particularly for medical use, a blue PET film colored in blue is preferably used.
[0055]
When the ink receiving layer coating solution is applied to the plastic resin film support, corona discharge treatment, flame treatment, ultraviolet irradiation treatment, plasma treatment and the like are usually performed prior to coating.
[0056]
In the present invention, a primer layer mainly composed of a synthetic resin is preferably provided on a light-transmitting support such as a plastic resin film. Transparency is further improved by applying a coating liquid for the ink receiving layer on the primer layer, then cooling and drying at a relatively low temperature.
[0057]
The primer layer provided on the film is mainly composed of synthetic resin. Examples of such synthetic resins include acrylic resins, polyester resins, vinylidene chloride, vinyl chloride resins, vinyl acetate resins, polystyrene, polyamide resins, polyurethane resins, and the like. Among these, acrylic resins, polyester resins, vinylidene chloride resins, and polyurethane resins are particularly preferable. As acrylic resins, homopolymers of acrylic acid alkyl esters and methacrylic acid alkyl esters or copolymers thereof are common. As the polyester resin, a polycondensate of a glycol (for example, ethylene glycol or diethylene glycol) and a polybasic acid such as an aliphatic or aromatic dibasic acid is generally used. The vinylidene chloride resin is preferably a homopolymer or a copolymer with an acrylic acid alkyl ester, a methacrylic acid alkyl ester and / or acrylonitrile. As the polyurethane resin, a water-dispersed polyurethane emulsion is preferable. These resins can be applied on the support as a solution or an aqueous solution of an organic solvent, but are preferably water-dispersible polymers, and are applied on the support as an emulsion or latex.
[0058]
These synthetic resins contain 60% by weight or more based on the total solid content constituting the primer layer. Preferably, 80% by weight or more is contained. Furthermore, the primer layer can contain a surfactant, a crosslinking agent such as isocyanate and epoxy, fine particles such as colloidal silica, and a water-soluble polymer such as gelatin and polyvinyl alcohol.
[0059]
The primer layer is provided on the support with a film thickness (dry film thickness) of 0.01 to 5 μm. Preferably it is the range of 0.05-5 micrometers.
[0060]
Various back coat layers can be coated on the support in the present invention for antistatic properties, transport properties, anticurling properties, and the like. In the backcoat layer, an inorganic antistatic agent, an organic antistatic agent, a hydrophilic binder, latex, a curing agent, a surfactant and the like can be appropriately combined.
[0061]
【Example】
EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, the content of this invention is not restricted to an Example.
[0062]
Examples 1 and 2
The light transmissive support shown below was prepared.
<Support A>
A surface of a polyethylene terephthalate film (opacity 15%) having a thickness of 175 μm and containing a blue inorganic pigment, which has been subjected to oxygen plasma treatment.
<Support B>
A primer layer having the following composition was provided on a polyethylene terephthalate film (opacity 15%) having a thickness of 175 μm and containing a blue inorganic pigment so as to have a dry film thickness of 0.3 μm.
Primer layer: Latex (weight average molecular weight 42000) of vinylidene chloride: methyl acrylate: acrylic acid (90: 9: 1, wt%).
[0063]
On the above two types of supports, an ink receiving layer coating solution having the following composition was coated with a slide bead coating device and dried. The ink receiving layer coating liquid shown below was prepared so as to have a solid content concentration of 10% by weight, and applied so that the solid content coating amount was 20 g / m ² . The one using the support A was used as the ink jet recording material of Example 1, and the one using the support B was used as the ink jet recording material of Example 2.
[0064]
<Ink-receiving layer coating solution>
Vapor phase method silica 95 parts (average primary particle size 7 nm, average secondary particle size 0.15 μm, dispersity 0.4)
Wet process silica 5 parts (Nippon Silica Co., Ltd., nip seal E-220A, average particle size 2 μm)
Dimethyldiallylammonium chloride homopolymer 3 parts Boric acid 4 parts Polyvinyl alcohol 20 parts (saponification degree 88%, average polymerization degree 3500)
Surfactant 0.3 part Zirconium acetate 2 parts
The drying conditions after coating are shown below.
After cooling at 5 ° C. for 30 seconds, the total solid concentration was dried at 45 ° C. and 10% RH until the total solid concentration was 90% by weight, and then dried at 35 ° C. and 10% RH.
[0066]
The ink jet recording material prepared as described above was evaluated as follows. The results are shown in Table 1.
[0067]
<Image clarity>
Using a Suga Test Instruments Co., Ltd. sex image clarity measuring device, the image clarity C value defined by JIS-H-8686 was measured with an optical comb width of 2.0 mm. The sample is fixed to the sample mount by a suction method so that the measured value does not decrease due to curling or the like. Each sample was measured 5 times and the average value was adopted. When the image clarity C value is greater than 85%, the visual sensation of glare is great. Preferably it is 83% or less.
[0068]
<Ink absorbability>
Using a plotter (Novajet-PRO42e manufactured by ENCAD) and GS ink, C, M, and Y are printed at 100% each. Immediately after printing, PPC paper is layered on the printing part and lightly pressed and transferred to PPC paper. The degree of ink amount was visually observed and evaluated according to the following criteria.
A: No transfer at all.
○: Slightly transferred.
Δ: Transfer is possible but actual use is possible.
X: Transfer is large and actual use is impossible.
[0069]
<Haze value of ink receiving layer>
The haze value specified by JIS-K-7105 of the polyethylene terephthalate film support used and the ink jet recording material obtained was measured using a Poick integrating sphere haze meter (manufactured by Nippon Seimitsu Optical Co., Ltd.). Calculated from
[0070]
<Surface strength>
A scotch clear tape (CH-24 manufactured by Sumitomo 3M Co., Ltd.) was bonded to the surface of the ink jet recording material, and it was quickly peeled off by hand, and the degree of peeling from the ink receiving layer on the tape adhesive surface was visually evaluated.
○: No peeling at all.
Δ: Slightly peeled off.
X: Peeling severely impractical.
[0071]
Example 3
An ink jet recording material of Example 3 was obtained in the same manner as in Example 2 except that the composition of the ink receiving layer in Example 2 was changed as follows. The evaluation results are shown in Table 1.
[0072]
<Ink-receiving layer coating solution>
Gas phase method silica 95 parts (average primary particle size 12 nm, average secondary particle size 0.2 μm, dispersity 0.3)
Wet process silica 5 parts (Nippon Silica Co., Ltd., nip seal E-220A, average particle size 2 μm)
Dimethyldiallylammonium chloride homopolymer 3 parts Boric acid 4 parts Polyvinyl alcohol 20 parts (saponification degree 88%, average polymerization degree 3500)
Surfactant 0.3 part Zirconium acetate 2 parts
Example 4
Table 1 shows the evaluation results of obtaining the ink jet recording material of Example 4 in the same manner as in Example 2 except that the formulation of the ink receiving layer in Example 2 was changed to the following.
[0074]
<Ink-receiving layer coating solution>
Gas phase method silica 28.5 parts (average primary particle size 7 nm, average secondary particle size 0.15 μm, dispersity 0.4)
Gas phase method silica 66.5 parts (average primary particle size 12 nm, average secondary particle size 0.2 μm, dispersity 0.3)
Wet process silica 5 parts (Nippon Silica Co., Ltd., nip seal E-220A, average particle size 2 μm)
Dimethyldiallylammonium chloride homopolymer 3 parts Boric acid 4 parts Polyvinyl alcohol 20 parts (saponification degree 88%, average polymerization degree 3500)
Surfactant 0.3 part Zirconium acetate 2 parts
Reference example 1
An ink jet recording material of Reference Example 1 was obtained in the same manner as in Example 2 except that the formulation of the ink receiving layer in Example 2 was changed to the following. The evaluation results are shown in Table 1.
[0076]
<Ink-receiving layer coating solution>
Gas phase method silica 84 parts (average primary particle size 7nm, average secondary particle size 0.15μm, dispersity 0.4)
Wet process silica 16 parts (Nippon Silica Co., Ltd., nip seal E-220A, average particle size 2 μm)
Dimethyldiallylammonium chloride homopolymer 3 parts Boric acid 4 parts Polyvinyl alcohol 20 parts (saponification degree 88%, average polymerization degree 3500)
Surfactant 0.3 part Zirconium acetate 2 parts
Example 5
An inkjet recording material of Example 5 was obtained in the same manner as in Example 2 except that the formulation of the ink receiving layer in Example 2 was changed to the following. The evaluation results are shown in Table 1.
[0078]
<Ink-receiving layer coating solution>
Gas phase method silica 98 parts (average primary particle size 7 nm, average secondary particle size 0.15 μm, dispersity 0.4)
Wet process silica 2 parts (manufactured by Tokuyama, Fine Seal X-12, average particle size 10 μm)
Dimethyldiallylammonium chloride homopolymer 3 parts Boric acid 4 parts Polyvinyl alcohol 20 parts (saponification degree 88%, average polymerization degree 3500)
Surfactant 0.3 part Zirconium acetate 2 parts
Example 6
An ink jet recording material of Example 6 was obtained in the same manner as in Example 1 except that zirconium acetate was removed by blending the ink receiving layer in Example 1. The evaluation results are shown in Table 1.
[0080]
Reference example 2
The ink jet recording material of Reference Example 2 was obtained in the same manner as in Example 1 except that the formulation of the ink receiving layer in Example 1 was changed to the following, and the solid content was 18 g / m ² . The evaluation results are shown in Table 1.
[0081]
<Ink-receiving layer coating solution>
Gelatin 50 parts Polyvinyl alcohol 45 parts (Kuraray Co., Ltd., KM-618)
Wet process silica 5 parts (Nippon Silica Co., Ltd., nip seal E-220A, average particle size 2 μm)
Surfactant 0.1 part [0082]
Comparative Example 1
The ink jet recording material of Comparative Example 1 was obtained in the same manner as in Example 1 except that the wet process synthetic silica blended with the ink receiving layer in Example 1 was omitted. The evaluation results are shown in Table 1.
[0083]
Comparative Example 2
Ink except that receiving layer disconnect the wet method synthesis silica formulation to obtain an ink jet recording material of Comparative Example 2 in the same manner as in Reference Example 2 in Reference Example 2. The evaluation results are shown in Table 1.
Comparative Example 3
An inkjet recording material of Comparative Example 3 was obtained in the same manner as in Example 1 except that the formulation of the ink receiving layer in Example 1 was changed to the following. The evaluation results are shown in Table 1.
[0084]
<Ink-receiving layer coating solution>
Gas phase method silica 81 parts (average primary particle size 7 nm, average secondary particle size 0.15 μm, dispersity 0.4)
Wet process silica 19 parts (manufactured by Tokuyama, Fine Seal X-12, average particle size 10 μm)
Dimethyldiallylammonium chloride homopolymer 3 parts Boric acid 4 parts Polyvinyl alcohol 20 parts (saponification degree 88%, average polymerization degree 3500)
Surfactant 0.3 part Zirconium acetate 2 parts
[Table 1]

[0086]
Results: Example 2 is a case where a primer layer was provided on the polyethylene terephthalate film used as a support in Example 1, but the haze value of the ink receiving layer was smaller than Example 1 and the transparency was improved. The image sharpness by transmitted light was good in both Examples 1 and 2. In Example 3, gas phase method silica was replaced with gas phase method silica having an average primary particle diameter of 12 nm. In Example 3, the image clarity was slightly lowered and the glare was apt to be lowered, the ink absorbability was improved, and the image sharpness was improved. The haze value increased, but the transparency of the ink receiving layer tended to decrease. Example 4 is a case where vapor phase method silica having an average primary particle size of 7 nm and 12 nm was mixed at a ratio of 30/70 in Example 2, but the haze value was slightly increased, but the ink absorbability was improved. The image sharpness was good. Reference Example 1 is a case where the wet process silica of the ink receiving layer is increased to 16 parts in Example 2, but the image clarity is lowered and the glare feeling is good, but the ink absorbability is lowered, and the haze value is The sharpness of the image by the transmitted light was the lower limit in actual use. Example 5 is the case where 2 parts of wet process silica having an average particle size of 10 μm is used, but the image clarity is high and the glare is the actual lower limit, the haze value is high and the image sharpness and surface strength tend to decrease. The roughness of the hand increased from Reference Example 1 where the wet process silica having an average particle diameter of 2 μm was increased to 16 parts, and was at the level of the actual lower limit of use. Example 6 is a case where zirconium acetate was removed in Example 1, but the haze value was slightly high and the transparency was lowered, but the image sharpness and the like were at a level with no problem. Reference Example 2 is a case where 5 parts of wet-process silica having an average particle diameter of 2 μm is contained in a gelatin / polyvinyl alcohol system. The haze value is lower than that in Example 1, but the transparency is good. The image sharpness was lowered due to a decrease in the reproducibility of the printed image, and the image clarity was high and the glare feeling was increased as compared with Example 1, but it was practically usable.
[0087]
Comparative Example 1 is a case where wet method silica was removed in Example 1, but the haze value was good and the image sharpness was good, but the image clarity was high and the glare was inferior. Comparative Example 2 was a case where wet method silica was removed in Reference Example 2 , but the haze value was very good, but the image clarity was high, the glare feeling increased, and it was at a problem level in actual use. Comparative Example 3 is a case where the weight ratio of the gas phase method silica having an average primary particle size of 7 nm and the wet method silica having an average particle size of 10 μm is 81/19 in Example 1, and the image clarity is low and good. However, the ink absorptivity was poor, the haze value of the ink receiving layer was high, and the image sharpness due to transmitted light was at a level causing problems in actual use.
[0088]
【The invention's effect】
As is apparent from the above results, according to the present invention, there is no problem of glaring due to the return light even when used in a backlight system for medical use, high transparency (low haze value), and high ink absorption. In addition, an ink jet recording material for backlit having good image reproducibility and surface strength can be obtained.

Claims (1)

In a backlit inkjet recording material for providing an ink receiving layer on a light-transmitting support and irradiating light from the surface opposite to the printing surface to observe an image from the printing surface , the ink receiving layer comprises secondary particles. Gas phase method silica and hydrophilic polymer as inorganic fine particles having an average particle size of less than 0.5 μm, and wet method silica as an inorganic pigment having an average particle size of 0.5 μm or more, and the inorganic pigment has a recording material unit area An ink jet recording material for backlit, characterized in that it contains 0.1 to 5 g / m ² and the haze value defined by JIS-K-7105 of the ink receiving layer is 18% or less .